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Sample records for bifunctional protein extremely

  1. sCD4-17b bifunctional protein: Extremely broad and potent neutralization of HIV-1 Env pseudotyped viruses from genetically diverse primary isolates

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    Dey Barna

    2010-02-01

    recombinant forms AE and AG. The neutralization breadth and potency were superior to what have been reported for the broadly neutralizing monoclonal antibodies IgG b12, 2G12, 2F5, and 4E10. The activity of sCD4-17b was found to be similar against isogenic virus particles from infectious molecular clones derived either directly from the transfected producer cell line or after a single passage through PBMCs; this contrasted with the monoclonal antibodies, which were less potent against the PMBC-passaged viruses. Conclusions The results highlight the extremely potent and broad neutralizing activity of sCD4-17b against genetically diverse HIV-1 primary isolates. The bifunctional protein has potential applications for antiviral approaches to combat HIV infection.

  2. Characterization of Afb, a novel bifunctional protein in Streptococcus agalactiae

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    Sanaz Dehbashi

    2016-03-01

    Full Text Available Background and Objectives: Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in newborns and results in pneumonia and bacteremia in adults. A number of S. agalactiae components are involved in colonization of target cells. Destruction of peptidoglycan and division of covalently linked daughter cells is mediated by autolysins. In this study, autolytic activity and plasma binding ability of AFb novel recombinant protein of S. agalactiae was investigated.Materials and Methods: The gbs1805 gene was cloned and expressed. E. coli strains DH5α and BL21 were used as cloning and expression hosts, respectively. After purification, antigenicity and binding ability to plasma proteins of the recombinant protein was evaluated.Results: AFb, the 18KDa protein was purified successfully. The insoluble mature protein revealed the ability to bind to fibrinogen and fibronectin. This insoluble mature protein revealed that it has the ability to bind to fibrinogen and fibronectin plasma proteins. Furthermore, in silico analysis demonstrated the AFb has an autolytic activity.Conclusions: AFb is a novel protein capable of binding to fibrinogen and fibronectin. This findings lay a ground work for further investigation of the role of the bacteria in adhesion and colonization to the host. Keywords: Streptococcus agalactiae, Fibrinogen, Fibronectin, Autolysin

  3. On the molecular basis of D-bifunctional protein deficiency type III.

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    Maija L Mehtälä

    Full Text Available Molecular basis of D-bifunctional protein (D-BP deficiency was studied with wild type and five disease-causing variants of 3R-hydroxyacyl-CoA dehydrogenase fragment of the human MFE-2 (multifunctional enzyme type 2 protein. Complementation analysis in vivo in yeast and in vitro enzyme kinetic and stability determinants as well as in silico stability and structural fluctuation calculations were correlated with clinical data of known patients. Despite variations not affecting the catalytic residues, enzyme kinetic performance (K(m, V(max and k(cat of the recombinant protein variants were compromised to a varying extent and this can be judged as the direct molecular cause for D-BP deficiency. Protein stability plays an additional role in producing non-functionality of MFE-2 in case structural variations affect cofactor or substrate binding sites. Structure-function considerations of the variant proteins matched well with the available data of the patients.

  4. Neurodegeneration in D-bifunctional protein deficiency: diagnostic clues and natural history using serial magnetic resonance imaging

    International Nuclear Information System (INIS)

    We report serial neurodegenerative changes on neuroimaging in a rare peroxisomal disease called D-bifunctional protein deficiency. The pattern of posterior to anterior demyelination with white matter disease resembles X-linked adrenoleukodystrophy. We feel this case is important to (1) highlight that D-bifunctional protein deficiency should be considered in cases where the neuroimaging resembles X-linked adrenoleukodystrophy, (2) to show different stages of progression to help identify this disease using neuroimaging in children, and (3) to show that neuroimaging suggesting a leukodystrophy can warrant peroxisomal beta-oxidation studies in skin fibroblasts even when plasma very long chain fatty acids are normal. (orig.)

  5. Neurodegeneration in D-bifunctional protein deficiency: diagnostic clues and natural history using serial magnetic resonance imaging

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    Khan, Aneal [University of Calgary, Department of Medical Genetics and Pediatrics, Alberta Children' s Hospital, Calgary, AB (Canada); Wei, Xing-Chang [University of Calgary, Department of Radiology, Alberta Children' s Hospital, Calgary, AB (Canada); Snyder, Floyd F. [Alberta Children' s Hospital, Biochemical Genetics Laboratory, Calgary, AB (Canada); Mah, Jean K. [University of Calgary, Division of Neurology, Department of Pediatrics, Calgary, AB (Canada); Waterham, Hans; Wanders, Ronald J.A. [University of Amsterdam, Academic Medical Center, Lab Genetic Metabolic Diseases, Amsterdam (Netherlands)

    2010-12-15

    We report serial neurodegenerative changes on neuroimaging in a rare peroxisomal disease called D-bifunctional protein deficiency. The pattern of posterior to anterior demyelination with white matter disease resembles X-linked adrenoleukodystrophy. We feel this case is important to (1) highlight that D-bifunctional protein deficiency should be considered in cases where the neuroimaging resembles X-linked adrenoleukodystrophy, (2) to show different stages of progression to help identify this disease using neuroimaging in children, and (3) to show that neuroimaging suggesting a leukodystrophy can warrant peroxisomal beta-oxidation studies in skin fibroblasts even when plasma very long chain fatty acids are normal. (orig.)

  6. Efficient refolding of the bifunctional therapeutic fusion protein VAS-TRAIL by a triple agent solution.

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    Fan, Jiying; Wang, Zhanqing; Huang, Liying; Shen, Yaling

    2016-09-01

    VAS-TRAIL is a bifunctional fusion protein that combines anti-angiogenic activity with tumor-selective apoptotic activity for enhanced anti-tumor efficacy. VAS-TRAIL is expressed as inclusion body in Escherichia coli, but protein refolding is difficult to achieve and results in low yields of bioactive protein. In this study, we describe an efficient method for VAS-TRAIL refolding. The solubilization of aggregated VAS-TRAIL was achieved by a triple agent solution, which consists of an alkaline solution (pH 11.5) containing 0.4M l-arginine and 2M urea. The solubilized protein showed high purity and preserved secondary structure according to fluorescence properties. VAS-TRAIL refolding was performed through stepwise dialysis and resulted in more than 50% recovery of the soluble protein. The function of l-arginine was additive with alkaline pH, as shown by the significant improvement in refolding yield (≈30%) by l-arginine-containing solubilization solutions compared with alkaline solubilization solutions without l-arginine. The refolded VAS-TRAIL also showed β-sheet structures and the propensity for oligomerization. Bioassays showed that the refolded fusion protein exhibited the expected activities, including its apoptotic activities toward tumor and endothelial cells, which proposed its promising therapeutic potential. PMID:26358405

  7. The use of bifunctional polyethyleneglycol derivatives for coupling of proteins to and cross-linking of collagen matrices.

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    Chen, J-S; Noah, E M; Pallua, N; Steffens, G C M

    2002-11-01

    The realization of three-dimensional (3D) degradable matrices which slowly release bio-active components represents a major challenge in the field of tissue engineering. In this paper we report on the usage of commercially available bifunctional agents for both the covalent coupling of proteins to and the cross-linking of collagen matrices. Proteins - horse radish peroxidase (HRP) was used as a model protein - were cross-linked with either a homobifunctional (disuccinimidyldisuccinatepolyethylene-glycol) or a heterobifunctional (N-hydroxysuccinimidylvinylsulfonepolyethyleneglycol) agent. In the case of the heterobifunctional cross-linking agent the collagen matrices were previously modified with succinimidylacetylthioacetate in order to introduce sulfhydryl groups. As compared with control experiments a 10-fold and 50-fold increase of immobilized proteins were achieved with the homobifunctional and heterobifunctional cross-linker resp. The HRP-PEG conjugates demonstrated a better long-term stability as compared to the non-treated HRP. The effects of the cross-linking agents and the thiolation reagent succinimidylacetylthio acetate on the in vitro degradation of the collagen matrices by collagenase were also investigated. In particular the reaction with succinimidylacetylthio acetate appears to offer interesting opportunities both for coupling active proteins and modulating the degradation times of collagen matrices. PMID:15348172

  8. Design of a bifunctional fusion protein for ovarian cancer drug delivery: single-chain anti-CA125 core-streptavidin fusion protein.

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    Wang, Welson Wen-Shang; Das, Dipankar; McQuarrie, Stephen A; Suresh, Mavanur R

    2007-03-01

    We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread. PMID:17257818

  9. Conversion of β-carotene into astaxanthin: Two separate enzymes or a bifunctional hydroxylase-ketolase protein?

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    Gudiña Eduardo

    2008-02-01

    Full Text Available Abstract Astaxanthin is a xanthophyll of great interest in animal nutrition and human health. The market prospect in the nutraceutics industries for this health-protective molecule is very promising. Astaxanthin is synthesized by several bacteria, algae and plants from β-carotene by the sequential action of two enzymes: a β-carotene, 3,3'-hydroxylase that introduces an hydroxyl group at the 3 (and 3' positions of each of the two β-ionone rings of β-carotene, and a β-carotene ketolase that introduces keto groups at carbons 4 and 4' of the β-ionone rings. Astaxanthin is also produced by the yeast-like basidiomycete Xanthophyllomyces dendrorhous. A gene crtS involved in the conversion of β-carotene to astaxanthin has been cloned simultaneously by two research groups. Complementation studies of X. dendrorhous mutants and expression analysis in Mucor circinelloides reveals that the CrtS enzyme is a β-carotene hydroxylase of the P-450 monooxygenase family that converts β-carotene to the hydroxylated derivatives β-cryptoxanthin and zeaxanthin, but it does not form astaxanthin or the ketolated intermediates in this fungus. A bifunctional β-carotene hydroxylase-ketolase activity has been proposed for the CrtS protein. The evidence for and against this hypothesis is analyzed in detail in this review.

  10. Construction of bifunctional molecules specific to antigen and antibody’s Fc-fragment by fusion of scFv-antibodies with staphylococcal protein A

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    Kolibo D. V.

    2009-06-01

    Full Text Available Aim. To develop approach for detection of scFv and their complexes with antigens. Methods. The fusion proteins, which include sequences of scFv and staphylococcal protein A, were constructed and the obtained bifunctional molecules were immunochemically analysed. Results. It was shown, that scFv fused with protein A and their complexes with antigens are effectively recognized by labelled immunoglobulins with unrestricted antigenic specificity. Conclusions. The fusion of scFv with protein A fragment is a perspective approach to increase the efficiency of application in ELISA. The obtained scFv, fused with protein A, could be used for development of test-systems for the detection of diphtheria toxin.

  11. Construction and evaluation of a novel bifunctional phenylalanine-formate dehydrogenase fusion protein for bienzyme system with cofactor regeneration.

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    Jiang, Wei; Fang, Bai-Shan

    2016-05-01

    Phenylalanine dehydrogenase (PheDH) plays an important role in enzymatic synthesis of L-phenylalanine for aspartame (sweetener) and detection of phenylketonuria (PKU), suggesting that it is important to obtain a PheDH with excellent characteristics. Gene fusion of PheDH and formate dehydrogenase (FDH) was constructed to form bifunctional multi-enzymes for bioconversion of L-phenylalanine coupled with coenzyme regeneration. Comparing with the PheDH monomer from Microbacterium sp., the bifunctional PheDH-FDH showed noteworthy stability under weakly acidic and alkaline conditions (pH 6.5-9.0). The bifunctional enzyme can produce 153.9 mM L-phenylalanine with remarkable performance of enantiomers choice by enzymatic conversion with high molecular conversion rate (99.87 %) in catalyzing phenylpyruvic acid to L-phenylalanine being 1.50-fold higher than that of the separate expression system. The results indicated the potential application of the PheDH and PheDH-FDH with coenzyme regeneration for phenylpyruvic acid analysis and L-phenylalanine biosynthesis in medical diagnosis and pharmaceutical field. PMID:26819086

  12. Sperm surface protein PH-20 is bifunctional: one activity is a hyaluronidase and a second, distinct activity is required in secondary sperm-zona binding.

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    Hunnicutt, G R; Primakoff, P; Myles, D G

    1996-07-01

    In previous studies, we have found that the sperm membrane protein PH-20 acts during two different stages of fertilization. On acrosome-intact sperm, PH-20 has a hyaluronidase activity that is required for sperm penetration through the cumulus cell layer that surrounds the oocyte. On acrosome-reacted sperm, PH-20 has a required function in sperm-zona binding (secondary binding). Because hyaluronic acid (HA) has been detected in the zona pellucida, secondary sperm-zona adhesion could depend on repetitive binding and hydrolysis of HA by PH-20 acting as a hyaluronidase. Alternatively, PH-20 may be bifunctional and have a second, different activity required for secondary binding. To distinguish between these two possibilities, in this study we used reagents that inhibit either PH-20's function in sperm-zona binding or its hyaluronidase activity. We found that an anti-PH-20 monoclonal antibody that inhibited sperm-zona binding (approximately 90%) had no effect on hyaluronidase activity. Conversely, apigenin, a hyaluronidase inhibitor, blocked PH-20 hyaluronidase activity 93% without inhibiting sperm-zona binding. Similarly, another anti-PH-20 monoclonal antibody that inhibited hyaluronidase activity 95% only partially inhibited sperm-zona binding (approximately 45%). We also extensively pretreated oocytes with hyaluronidase to remove all accessible HA on or in the zona pellucida and found little or no effect on secondary sperm-zona binding. Our results suggest that PH-20 is bifunctional and has two activities: a hyaluronidase activity and a second, separate activity required for secondary sperm-zona binding. PMID:8793062

  13. Cross-linking with bifunctional reagents and its application to the study of the molecular symmetry and the arrangement of subunits in hexameric protein oligomers.

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    Azem, Abdussalam; Tsfadia, Yossi; Hajouj, Omar; Shaked, Isabella; Daniel, Ezra

    2010-04-01

    Cross-linking with a bifunctional reagent and subsequent SDS gel electrophoresis is a simple but effective method to study the symmetry and arrangement of subunits in oligomeric proteins. In this study, theoretical expressions for the description of cross-linking patterns were derived for protein homohexamers through extension of the method used for tetramers by Hajdu et al. (1976). The derived equations were used for the analysis of cross-linking by glutardialdehyde of four protein hexamers: beef liver glutamate dehydrogenase (GDH), jack bean urease, hemocyanin from the spiny lobster Panulirus pencillatus (PpHc), Escherichia coli glutamate decarboxylase (GDC) and for analysis of published data on the cross-linking of hexameric E. coli rho by dimethyl suberimidate. Best fit models showed that the subunits in the first four proteins are arranged according to D(3) symmetry in two layers, each subunit able to cross-link to three neighboring subunits for GDH and urease, or to four for PpHc and GDC. The findings indicate a dimer-of-trimers eclipsed arrangement of subunits for GDH and urease and a trimer-of-dimers staggered one for PpHc and GDC. In rho, the subunits are arranged according to D(3) symmetry in a trimer-of-dimers ring. The conclusions from cross-linking of GDH and GDC, PpHc and rho are consistent with results from X-ray crystal structure, those for urease with findings from electron microscopy. PMID:20005307

  14. Protein Sequence Classification with Improved Extreme Learning Machine Algorithms

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    Jiuwen Cao

    2014-01-01

    Full Text Available Precisely classifying a protein sequence from a large biological protein sequences database plays an important role for developing competitive pharmacological products. Comparing the unseen sequence with all the identified protein sequences and returning the category index with the highest similarity scored protein, conventional methods are usually time-consuming. Therefore, it is urgent and necessary to build an efficient protein sequence classification system. In this paper, we study the performance of protein sequence classification using SLFNs. The recent efficient extreme learning machine (ELM and its invariants are utilized as the training algorithms. The optimal pruned ELM is first employed for protein sequence classification in this paper. To further enhance the performance, the ensemble based SLFNs structure is constructed where multiple SLFNs with the same number of hidden nodes and the same activation function are used as ensembles. For each ensemble, the same training algorithm is adopted. The final category index is derived using the majority voting method. Two approaches, namely, the basic ELM and the OP-ELM, are adopted for the ensemble based SLFNs. The performance is analyzed and compared with several existing methods using datasets obtained from the Protein Information Resource center. The experimental results show the priority of the proposed algorithms.

  15. Synthesis and evaluation of two new bifunctional carboxymethylated tetraazamacrocyclic chelating agents for protein labeling with indium-111

    Energy Technology Data Exchange (ETDEWEB)

    Ruser, G.; Ritter, W.; Maecke, H.R. (Univ. Hospital Basel (Switzerland))

    1990-09-01

    The synthesis of two new N- and C-functionalized tetraazamacrocyclic ligands intended to be covalently linked to biomolecules like monoclonal antibodies and to bind the gamma-emitting isotope indium-111 in a thermodynamically and/or kinetically inert way is described. 12-(p-Nitrobenzyl)-1,4,7,10-tetraazacyclotridecane-1,4,7,10-tetraa cetic acid (L1) was synthesized by means of bimolecular cyclization with the appropriate malonic acid diethyl ester and triethylenetetraamine, followed by reduction with diborane and alkylation of the cyclic tetraamine with bromoacetic acid. The corresponding triscarboxymethylated ligand L2 was made by statistical alkylation of the tetraamine. Both ligands fulfill the criteria for antibody labeling using the bifunctional chelate approach, namely fast chelate formation, high radiochemical yield, and high stability under physiological conditions. Surprisingly the heptadentate ligand L2 confers higher stability to In3+ and exhibits faster complex formation than octadentate L1. 13C NMR spectra in solution indicate that the difference in stability is not due to incomplete coordination of all four carboxylate groups in In-L1.

  16. Loss of allosteric control but retention of the bifunctional catalytic competence of a fusion protein formed by excision of 260 base pairs from the 3' terminus of pheA from Erwinia herbicola.

    OpenAIRE

    Xia, T.; Zhao, G.; Jensen, R A

    1992-01-01

    A bifunctional protein denoted as the P protein and encoded by pheA is widely present in purple gram-negative bacteria. This P protein carries catalytic domains that specify chorismate mutase (CM-P) and prephenate dehydratase. The instability of a recombinant plasmid carrying a pheA insert cloned from Erwinia herbicola resulted in a loss of 260 bp plus the TAA stop codon from the 3' terminus of pheA. The plasmid carrying the truncated pheA gene (denoted pheA*) was able to complement an Escher...

  17. Bifunctional alkaline oxygen electrodes

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    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

  18. Hierarchy and extremes in selections from pools of randomized proteins.

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    Boyer, Sébastien; Biswas, Dipanwita; Kumar Soshee, Ananda; Scaramozzino, Natale; Nizak, Clément; Rivoire, Olivier

    2016-03-29

    Variation and selection are the core principles of Darwinian evolution, but quantitatively relating the diversity of a population to its capacity to respond to selection is challenging. Here, we examine this problem at a molecular level in the context of populations of partially randomized proteins selected for binding to well-defined targets. We built several minimal protein libraries, screened them in vitro by phage display, and analyzed their response to selection by high-throughput sequencing. A statistical analysis of the results reveals two main findings. First, libraries with the same sequence diversity but built around different "frameworks" typically have vastly different responses; second, the distribution of responses of the best binders in a library follows a simple scaling law. We show how an elementary probabilistic model based on extreme value theory rationalizes the latter finding. Our results have implications for designing synthetic protein libraries, estimating the density of functional biomolecules in sequence space, characterizing diversity in natural populations, and experimentally investigating evolvability (i.e., the potential for future evolution). PMID:26969726

  19. Tight bifunctional hierarchical catalyst.

    Science.gov (United States)

    Højholt, Karen T; Vennestrøm, Peter N R; Tiruvalam, Ramchandra; Beato, Pablo

    2011-12-28

    A new concept to prepare tight bifunctional catalysts has been developed, by anchoring CoMo(6) clusters on hierarchical ZSM-5 zeolites for simultaneous use in HDS and hydrocracking catalysis. The prepared material displays a significant improved activity in HDS catalysis compared to the impregnated counterpart. PMID:22048337

  20. [Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

    International Nuclear Information System (INIS)

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III)

  1. [Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  2. (Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  3. Azidopropylvinylsulfonamide as a New Bifunctional Click Reagent for Bioorthogonal Conjugations: Application for DNA-Protein Cross-Linking

    Czech Academy of Sciences Publication Activity Database

    Daďová, Jitka; Vrábel, Milan; Adámik, Matěj; Brázdová, Marie; Pohl, Radek; Fojta, Miroslav; Hocek, Michal

    2015-01-01

    Roč. 21, č. 45 (2015), s. 16091-16102. ISSN 0947-6539 R&D Projects: GA ČR GBP206/12/G151 Institutional support: RVO:61388963 ; RVO:68081707 Keywords : biotransformations * click chemistry * conjugation * nucleic acids * proteins Subject RIV: CC - Organic Chemistry Impact factor: 5.731, year: 2014

  4. Specific combination of compound heterozygous mutations in 17β-hydroxysteroid dehydrogenase type 4 (HSD17B4 defines a new subtype of D-bifunctional protein deficiency

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    McMillan Hugh J

    2012-11-01

    Full Text Available Abstract Background D-bifunctional protein (DBP deficiency is typically apparent within the first month of life with most infants demonstrating hypotonia, psychomotor delay and seizures. Few children survive beyond two years of age. Among patients with prolonged survival all demonstrate severe gross motor delay, absent language development, and severe hearing and visual impairment. DBP contains three catalytically active domains; an N-terminal dehydrogenase, a central hydratase and a C-terminal sterol carrier protein-2-like domain. Three subtypes of the disease are identified based upon the domain affected; DBP type I results from a combined deficiency of dehydrogenase and hydratase activity; DBP type II from isolated hydratase deficiency and DBP type III from isolated dehydrogenase deficiency. Here we report two brothers (16½ and 14 years old with DBP deficiency characterized by normal early childhood followed by sensorineural hearing loss, progressive cerebellar and sensory ataxia and subclinical retinitis pigmentosa. Methods and results Biochemical analysis revealed normal levels of plasma VLCFA, phytanic acid and pristanic acid, and normal bile acids in urine; based on these results no diagnosis was made. Exome analysis was performed using the Agilent SureSelect 50Mb All Exon Kit and the Illumina HiSeq 2000 next-generation-sequencing (NGS platform. Compound heterozygous mutations were identified by exome sequencing and confirmed by Sanger sequencing within the dehydrogenase domain (c.101C>T; p.Ala34Val and hydratase domain (c.1547T>C; p.Ile516Thr of the 17β-hydroxysteroid dehydrogenase type 4 gene (HSD17B4. These mutations have been previously reported in patients with severe-forms of DBP deficiency, however each mutation was reported in combination with another mutation affecting the same domain. Subsequent studies in fibroblasts revealed normal VLCFA levels, normal C26:0 but reduced pristanic acid beta-oxidation activity. Both DBP

  5. Identification of antithrombin-modulating genes. Role of LARGE, a gene encoding a bifunctional glycosyltransferase, in the secretion of proteins?

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    María Eugenia de la Morena-Barrio

    Full Text Available The haemostatic relevance of antithrombin together with the low genetic variability of SERPINC1, and the high heritability of plasma levels encourage the search for modulating genes. We used a hypothesis-free approach to identify these genes, evaluating associations between plasma antithrombin and 307,984 polymorphisms in the GAIT study (352 individuals from 21 Spanish families. Despite no SNP reaching the genome wide significance threshold, we verified milder positive associations in 307 blood donors from a different cohort. This validation study suggested LARGE, a gene encoding a protein with xylosyltransferase and glucuronyltransferase activities that forms heparin-like linear polysaccharides, as a potential modulator of antithrombin based on the significant association of one SNPs, rs762057, with anti-FXa activity, particularly after adjustment for age, sex and SERPINC1 rs2227589 genotype, all factors influencing antithrombin levels (p = 0.02. Additional results sustained this association. LARGE silencing inHepG2 and HEK-EBNA cells did not affect SERPINC1 mRNA levels but significantly reduced the secretion of antithrombin with moderate intracellular retention. Milder effects were observed on α1-antitrypsin, prothrombin and transferrin. Our study suggests LARGE as the first known modifier of plasma antithrombin, and proposes a new role for LARGE in modulating extracellular secretion of certain glycoproteins.

  6. Discovery of Bifunctional Oncogenic Target Inhibitors against Allosteric Mitogen-Activated Protein Kinase (MEK1) and Phosphatidylinositol 3-Kinase (PI3K).

    Science.gov (United States)

    Van Dort, Marcian E; Hong, Hao; Wang, Hanxiao; Nino, Charles A; Lombardi, Rachel L; Blanks, Avery E; Galbán, Stefanie; Ross, Brian D

    2016-03-24

    The synthesis of a series of single entity, bifunctional MEK1/PI3K inhibitors achieved by covalent linking of structural analogs of the ATP-competitive PI3K inhibitor ZSTK474 and the ATP-noncompetitive MEK inhibitor PD0325901 is described. Inhibitors displayed potent in vitro inhibition of MEK1 (0.015 strategy toward combined MEK1/PI3K inhibition. PMID:26943489

  7. Behavior of whey protein concentrates under extreme storage conditions

    Science.gov (United States)

    The overseas demand for whey protein concentrates (WPC) has increased steadily in recent years. Emergency aid foods often include WPC, but shelf-life studies of whey proteins under different shipment and storage conditions have not been conducted in the last 50 yr. Microbial quality, compound form...

  8. Protein stability and enzyme activity at extreme biological temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Feller, Georges, E-mail: gfeller@ulg.ac.b [Laboratory of Biochemistry, Centre for Protein Engineering, Institute of Chemistry B6a, University of Liege, B-4000 Liege (Belgium)

    2010-08-18

    Psychrophilic microorganisms thrive in permanently cold environments, even at subzero temperatures. To maintain metabolic rates compatible with sustained life, they have improved the dynamics of their protein structures, thereby enabling appropriate molecular motions required for biological activity at low temperatures. As a consequence of this structural flexibility, psychrophilic proteins are unstable and heat-labile. In the upper range of biological temperatures, thermophiles and hyperthermophiles grow at temperatures > 100 {sup 0}C and synthesize ultra-stable proteins. However, thermophilic enzymes are nearly inactive at room temperature as a result of their compactness and rigidity. At the molecular level, both types of extremophilic proteins have adapted the same structural factors, but in opposite directions, to address either activity at low temperatures or stability in hot environments. A model based on folding funnels is proposed accounting for the stability-activity relationships in extremophilic proteins. (topical review)

  9. Catalysis and protein folding in extreme temperature environments

    OpenAIRE

    Gerday, C

    2013-01-01

    The diversity of life partially derives from the various characteristics of natural environments encountered on planet Earth suggesting that an organism, embedded in an environment exhibiting specific properties, will benefit from physiological and biochemical adjustments tending to optimize the adequacy between this environment and the overall characteristics of the organism. Some environments are extreme meaning that as such they are not suitable for organisms such as human being or Escheri...

  10. Isolation and characterization of bifunctional Escherichia coli TatA mutant proteins that allow efficient Tat-dependent protein translocation in the absence of TatB

    OpenAIRE

    Blaudeck, N.; Kreutzenbeck, P.; Müller, M; Sprenger, G.; Freudl, R

    2005-01-01

    In Escherichia coli, the Tat system promotes the membrane translocation of a subset of exported proteins across the cytoplasmic membrane. Four genes (tatA, tatB, tatC, and tatE) have been identified that encode the components of the E. coli Tat translocation apparatus. Whereas TatA and TatE can functionally substitute for each other, the TatB and the TatC proteins have been shown to perform distinct functions. In contrast to Tat systems of the ABC(E) type found in E. coli and many other bacte...

  11. Bifunctional redox flow battery

    International Nuclear Information System (INIS)

    A new bifunctional redox flow battery (BRFB) system, V(III)/V(II)-L-cystine(O2), was systematically investigated by using different separators. It is shown that during charge, water transfer is significantly restricted with increasing the concentration of HBr when the Nafion 115 cation exchange membrane is employed. The same result can be obtained when the gas diffusion layer (GDL) hot-pressed separator is used. The organic electro-synthesis is directly correlated with the crossover of vanadium. When employing the anion exchange membrane, the electro-synthesis efficiency is over 96% due to a minimal crossover of vanadium. When the GDL hot-pressed separator is applied, the crossover of vanadium and water transfer are noticeably prevented and the electro-synthesis efficiency of over 99% is obtained. Those impurities such as vanadium ions and bromine can be eliminated through the purification of organic electro-synthesized products. The purified product is identified to be L-cysteic acid by IR spectrum. The BRFB shows a favorable discharge performance at a current density of 20 mA cm-2. Best discharge performance is achieved by using the GDL hot-pressed separator. The coulombic efficiency of 87% and energy efficiency of about 58% can be obtained. The cause of major energy losses is mainly associated with the cross-contamination of anodic and cathodic active electrolytes

  12. Thermal adaptation analyzed by comparison of protein sequences from mesophilic and extremely thermophilic Methanococcus species

    OpenAIRE

    Haney, Paul J.; Jonathan H Badger; Buldak, Gerald L.; Reich, Claudia I.; Woese, Carl R.; Olsen, Gary J.

    1999-01-01

    The genome sequence of the extremely thermophilic archaeon Methanococcus jannaschii provides a wealth of data on proteins from a thermophile. In this paper, sequences of 115 proteins from M. jannaschii are compared with their homologs from mesophilic Methanococcus species. Although the growth temperatures of the mesophiles are about 50°C below that of M. jannaschii, their genomic G+C contents are nearly identical. The properties most correlated with the proteins of the thermophile include hig...

  13. [The effect of extremely low doses of the novel regulatory plant proteins ].

    Science.gov (United States)

    Krasnov, M S; Margasiuk, D V; Iamskov, I A; Iamskova, V P

    2003-01-01

    Searching and study on regulatory proteins, which can keep under control the scope of important processes as like as cell adhesion, proliferation, differentiation and morphogenesis, is an actual aim of the current biochemistry. Recently we have identified S-100 proteins in plants of following species: plantain (Plantago major L.), aloe (Aloe arborescens L.), and bilberry (Vaccinum myrtillus L.). Extraction and purification of S-100 proteins gotten from these plants were performed by the method we developed earlier for adhesion proteins of animal tissues. Homogeneity of the studied plant proteins was evaluated and confirmed by HPLC and SDS-electrophoresis in PAAG. Both, plant and animal proteins have appeared to be biologically active at extremely low doses. The tests were performed by adhesiometrical method in short-term tissue culture of mouse's liver in vitro. As a result it was established that the plant proteins insert a membranotropic effect being added in extremely low doses, corresponding to 10(-10)-10(-13) mg/ml. Keeping in mind that the plantain is well known remedy for wound protection and healing, in several experiments we studied the biological effect of plant S-100 proteins on animal cells. It was found that S-100 proteins obtained from plantain influences proliferation of human fibroblasts in vitro. It was found that after the treatment with this protein in low doses the cell growth rate increases essentially. PMID:12881977

  14. Eukaryotic evolutionary transitions are associated with extreme codon bias in functionally-related proteins.

    Directory of Open Access Journals (Sweden)

    Nicholas J Hudson

    Full Text Available Codon bias in the genome of an organism influences its phenome by changing the speed and efficiency of mRNA translation and hence protein abundance. We hypothesized that differences in codon bias, either between-species differences in orthologous genes, or within-species differences between genes, may play an evolutionary role. To explore this hypothesis, we compared the genome-wide codon bias in six species that occupy vital positions in the Eukaryotic Tree of Life. We acquired the entire protein coding sequences for these organisms, computed the codon bias for all genes in each organism and explored the output for relationships between codon bias and protein function, both within- and between-lineages. We discovered five notable coordinated patterns, with extreme codon bias most pronounced in traits considered highly characteristic of a given lineage. Firstly, the Homo sapiens genome had stronger codon bias for DNA-binding transcription factors than the Saccharomyces cerevisiae genome, whereas the opposite was true for ribosomal proteins--perhaps underscoring transcriptional regulation in the origin of complexity. Secondly, both mammalian species examined possessed extreme codon bias in genes relating to hair--a tissue unique to mammals. Thirdly, Arabidopsis thaliana showed extreme codon bias in genes implicated in cell wall formation and chloroplast function--which are unique to plants. Fourthly, Gallus gallus possessed strong codon bias in a subset of genes encoding mitochondrial proteins--perhaps reflecting the enhanced bioenergetic efficiency in birds that co-evolved with flight. And lastly, the G. gallus genome had extreme codon bias for the Ciliary Neurotrophic Factor--which may help to explain their spontaneous recovery from deafness. We propose that extreme codon bias in groups of genes that encode functionally related proteins has a pathway-level energetic explanation.

  15. The ProVIDe study: the impact of protein intravenous nutrition on development in extremely low birthweight babies

    OpenAIRE

    Bloomfield, Frank H.; Crowther, Caroline A; Harding, Jane E; Cathryn A. Conlon; Jiang, Yannan; Cormack, Barbara E.

    2015-01-01

    Background Preterm birth and very small size at birth have long-term effects on neurodevelopment and growth. A relatively small percentage of extremely low birthweight babies suffer from severe neurological disability; however, up to 50 % experience some neurodevelopmental or learning disability in childhood. Current international consensus is that increased protein intake in the neonatal period improves both neurodevelopment and growth, but the quantum of protein required is not known. This ...

  16. GST-TAT-SOD: Cell Permeable Bifunctional Antioxidant Enzyme—A Potential Selective Radioprotector

    OpenAIRE

    Jianru Pan; Huocong He; Ying Su; Guangjin Zheng; Junxin Wu; Shutao Liu; Pingfan Rao

    2016-01-01

    Superoxide dismutase (SOD) fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST), SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wi...

  17. Greater Mortality and Morbidity in Extremely Preterm Infants Fed a Diet Containing Cow Milk Protein Products

    OpenAIRE

    Abrams, Steven A.; Schanler, Richard J.; Lee, Martin L.; Rechtman, David J.

    2014-01-01

    Background: Provision of human milk has important implications for the health and outcomes of extremely preterm (EP) infants. This study evaluated the effects of an exclusive human milk diet on the health of EP infants during their stay in the neonatal intensive care unit.

  18. Bifunctional Chelates for Metal Nuclides

    OpenAIRE

    Brechbiel, Martin W.

    2007-01-01

    The use of “non-standard” metallic radionuclides continues to be an expanding field of investigation. Radiolabeling small molecules, peptides, proteins, and up to nano-particles are all areas of active investigation for both diagnostic and therapeutic applications. All require a common variable – the need for appropriate chelation chemistry for adequate sequestration of the metallic radionuclide that is equal to the intended application. A brief overview of the array of the chelation chemistr...

  19. Electrophoresis and isoelectric focusing of whole cell and membrane proteins from the extremely halophilic archaebacteria

    Science.gov (United States)

    Stan-Lotter, Helga; Lang, Frank J., Jr.; Hochstein, Lawrence I.

    1989-01-01

    The subunits from two purified halobacterial membrane enzymes (ATPase and nitrate reductase) behaved differently with respect to isoelectric focusing, silver staining and interaction with ampholytes. Differential behavior was also observed in whole cell proteins from Halobacterium saccharovorum regarding resolution in two-dimensional gels and silver staining. It is proposed that these differences reflect the existence of two classes of halobacterial proteins.

  20. Protein (Cyanobacteria): 392180 [

    Lifescience Database Archive (English)

    Full Text Available ZP_07113914.1 1117:24513 1150:7038 1158:3915 272129:3709 Bifunctional protein birA (Includes: Biotin ... otin operon repressor; Biotin --(acetyl-CoA-carboxylase) synthetase (Biotin --prot ...

  1. Prediction of hot spots in protein interfaces using extreme learning machines with the information of spatial neighbour residues.

    Science.gov (United States)

    Wang, Lin; Zhang, Wenjuan; Gao, Qiang; Xiong, Congcong

    2014-08-01

    The identification of hot spots, a small subset of protein interfaces that accounts for the majority of binding free energy, is becoming increasingly important for the research on protein-protein interaction and drug design. For each interface residue or target residue to be predicted, the authors extract hybrid features which incorporate a wide range of information of the target residue and its spatial neighbor residues, that is, the nearest contact residue in the other face (mirror-contact residue) and the nearest contact residue in the same face (intra-contact residue). Here, feature selection is performed using random forests to avoid over-fitting. Thereafter, the extreme learning machine is employed to effectively integrate these hybrid features for predicting hot spots in protein interfaces. By the 5-fold cross validation in the training set, their method can achieve accuracy (ACC) of 82.1% and Matthew's correlation coefficient (MCC) of 0.459, and outperforms some alternative machine learning methods in the comparison study. Furthermore, their method achieves ACC of 76.8% and MCC of 0.401 in the independent test set, and is more effective than the major existing hot spot predictors. Their prediction method offers a powerful tool for uncovering candidate residues in the studies of alanine scanning mutagenesis for functional protein interaction sites. PMID:25075532

  2. Structure-specific tRNA-binding protein from the extreme thermophile Aquifex aeolicus.

    OpenAIRE

    Morales, A. J; Swairjo, M A; Schimmel, P

    1999-01-01

    The genome of the bacterium Aquifex aeolicus encodes a polypeptide which is related to a small portion of a sequence found in one prokaryotic and two eukaryotic tRNA synthetases. It also is related to a portion of Arc1p, a tRNA-binding protein believed to be important for nuclear trafficking of tRNAs. Here we cloned, expressed and purified the 111 amino acid polypeptide (designated Trbp111) and showed by ultracentrifugation analysis that it is a stable dimer in solution. The protein was also ...

  3. Structural adaptation of extreme halophilic proteins through decrease of conserved hydrophobic contact surface

    Directory of Open Access Journals (Sweden)

    Siglioccolo Alessandro

    2011-12-01

    Full Text Available Abstract Background Halophiles are extremophilic microorganisms growing optimally at high salt concentrations. There are two strategies used by halophiles to maintain proper osmotic pressure in their cytoplasm: accumulation of molar concentrations of potassium and chloride with extensive adaptation of the intracellular macromolecules ("salt-in" strategy or biosynthesis and/or accumulation of organic osmotic solutes ("osmolyte" strategy. Our work was aimed at contributing to the understanding of the shared molecular mechanisms of protein haloadaptation through a detailed and systematic comparison of a sample of several three-dimensional structures of halophilic and non-halophilic proteins. Structural differences observed between the "salt-in" and the mesophilic homologous proteins were contrasted to those observed between the "osmolyte" and mesophilic pairs. Results The results suggest that haloadaptation strategy in the presence of molar salt concentration, but not of osmolytes, necessitates a weakening of the hydrophobic interactions, in particular at the level of conserved hydrophobic contacts. Weakening of these interactions counterbalances their strengthening by the presence of salts in solution and may help the structure preventing aggregation and/or loss of function in hypersaline environments. Conclusions Considering the significant increase of biotechnology applications of halophiles, the understanding of halophilicity can provide the theoretical basis for the engineering of proteins of great interest because stable at concentrations of salts that cause the denaturation or aggregation of the majority of macromolecules.

  4. Bifunctional electrocatalyst for oxygen/air electrodes

    International Nuclear Information System (INIS)

    Highlights: • Nano-Silver powder was prepared by chemical method. • Ag catalyst was characterized by SEM and XRD studies. • Ag was investigated as bi-functional electrocatalyst for oxygen/air electrodes. • Ag shows good electrochemical activity towards OER and ORR reactions. - Abstract: Nano-Silver powder has been studied as bi-functional electrocatalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline medium. Ag nano-powder has been prepared by a simple wet chemical method with Silver nitrate as precursor and Glucose as reducing agent. X-ray Diffraction and Scanning Electron Microscopy studies were carried out to characterize the Silver catalyst. Electrochemical oxygen evolution characterization shows anodic peak typically at the range between 0.350 and 0.514 V Vs Hg/HgO corresponding to Silver oxidation followed by the onset of oxygen evolution at 0.706 V. Oxygen reduction reaction studies carried out using Rotating Disc Electrode (RDE) confirm the four electron reaction mechanism. Ag catalyst shows promising characteristics for oxygen evolution and oxygen reduction

  5. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    OpenAIRE

    Zecevic, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan

    2015-01-01

    The ability to precisely control nanoscale features is increasingly exploited to develop and improve monofunctional catalysts1–4. Striking effects might also be expected in the case of bifunctional catalysts, which play an important role in hydrocracking of fossil and renewable hydrocarbon sources to provide high-quality diesel fuel5–7. Such bifunctional hydrocracking catalysts contain metal sites and acid sites, and for more than 50 years the so-called ‘intimacy criterion’8 has dictated the ...

  6. Nanoparticle Superlattices as Efficient Bifunctional Electrocatalysts for Water Splitting.

    Science.gov (United States)

    Li, Jun; Wang, Yongcheng; Zhou, Tong; Zhang, Hui; Sun, Xuhui; Tang, Jing; Zhang, Lijuan; Al-Enizi, Abdullah M; Yang, Zhongqin; Zheng, Gengfeng

    2015-11-18

    The solar-driven water splitting process is highly attractive for alternative energy utilization, while developing efficient, earth-abundant, bifunctional catalysts for both oxygen evolution reaction and hydrogen evolution reaction has remained as a major challenge. Herein, we develop an ordered CoMnO@CN superlattice structure as an efficient bifunctional water-splitting electrocatalyst, in which uniform Co-Mn oxide (CoMnO) nanoparticles are coated with a thin, continuous nitrogen-doped carbon (CN) framework. The CoMnO nanoparticles enable optimized OER activity with effective electronic structure configuration, and the CN framework serves as an excellent HER catalyst. Importantly, the ordered superlattice structure is beneficial for enhanced reactive sites, efficient charge transfer, and structural stability. This bifunctional superlattice catalyst manifests optimized current densities and electrochemical stability in overall water splitting, outperforming most of the previously reported single- or bifunctional electrocatalysts. Combining with a silicon photovoltaic cell, this CoMnO@CN superlattice bifunctional catalyst enables unassisted solar water splitting continuously for ∼5 days with a solar-to-hydrogen conversion efficiency of ∼8.0%. Our discovery suggests that these transition metal oxide-based superlattices may serve as a unique structure modality for efficient bifunctional water splitting electrocatalysts with scale-up potentials. PMID:26496655

  7. Influence of extremely low frequency magnetic field on total protein and –SH groups concentrations in liver homogenates

    Directory of Open Access Journals (Sweden)

    Elżbieta Ciejka

    2014-10-01

    Full Text Available Background: Free radicals are atoms, molecules or their fragments, whose excess leads to the development of oxidative stress, the cause of many neoplastic, neurodegenerative and inflammatory diseases, as well as aging of organisms. Industrial pollution, tobacco smoke, ionizing radiation, ultrasound and magnetic fields are the major exogenous sources of free radicals. The low frequency magnetic field is commonly applied in physiotherapy. The aim of the present study was to evaluate the effect of extremely low frequency magnetic field (ELF-MF on the concentration of sulfhydryl groups (–SH and proteins in liver tissues of experimental animals depending on the time of exposure to the field. Material and Methods: Twenty one Sprague-Dawley male rats, aged 3–4 months were randomly divided into 3 experimental groups (each containing 7 animals: controls (group I, the rats exposed to ELF-MF of 40 Hz, 7 mT (this kind of the ELF-MF is mostly used in magnetotherapy, 30 min/day for 2 weeks (group II and the rats exposed to 40 Hz, 7 mT for 60 min/day for 2 weeks (group III. The concentrations of proteins and sulfhydryl groups in the liver tissues were determined after exposure to magnetic fields. Results: Exposure to low magnetic field: 40 Hz, 7 mT for 30 min/day and 60 min/day for 2 weeks caused a significant increase in the concentration of –SH groups and total protein levels in the liver tissues. Conclusions: The study results suggest that exposure to magnetic fields leads to the development of adaptive mechanisms to maintain the balance in the body oxidation-reduction and in the case of the studied parameters does not depend on the time of exposure. Med Pr 2014;65(5:639–644

  8. A highly conserved glycine within linker I and the extreme C terminus of G protein alpha subunits interact cooperatively in switching G protein-coupled receptor-to-effector specificity

    DEFF Research Database (Denmark)

    Kostenis, Evi; Martini, Lene; Ellis, James; Waldhoer, Maria; Heydorn, Arne; Rosenkilde, Mette M; Norregaard, Pia K; Jorgensen, Rasmus; Whistler, Jennifer L; Milligan, Graeme

    2004-01-01

    Numerous studies have attested to the importance of the extreme C terminus of G protein alpha subunits in determining their selectivity of receptor recognition. We have previously reported that a highly conserved glycine residue within linker I is important for constraining the fidelity of receptor...... recognition by Galpha(q) proteins. Herein, we explored whether both modules (linker I and extreme C terminus) interact cooperatively in switching G protein-coupled receptor (GPCR)-to-effector specificity and created as models mutant Galpha(q) proteins in which glycine was replaced with various amino acids and...... the C-terminal five Galpha(q) residues with the corresponding Galpha(i) or Galpha(s) sequence. Coupling properties of the mutated Galpha(q) proteins were determined after coexpression with a panel of 13 G(i)-and G(s) -selective receptors and compared with those of Galpha proteins modified in only one...

  9. Cloning, expression, purification and preliminary crystallographic analysis of the RNase HI domain of the Mycobacterium tuberculosis protein Rv2228c as a maltose-binding protein fusion

    OpenAIRE

    Watkins, Harriet A.; Baker, Edward N.

    2008-01-01

    The ribonuclease HI domain of a bifunctional protein Rv2228c-CobC from M. tuberculosis has been crystallized as a fusion protein with maltose-binding protein in a form suitable for high-resolution crystallographic analysis.

  10. Trypanosoma brucei DHFR-TS Revisited: Characterisation of a Bifunctional and Highly Unstable Recombinant Dihydrofolate Reductase-Thymidylate Synthase.

    Science.gov (United States)

    Gibson, Marc W; Dewar, Simon; Ong, Han B; Sienkiewicz, Natasha; Fairlamb, Alan H

    2016-05-01

    Bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) is a chemically and genetically validated target in African trypanosomes, causative agents of sleeping sickness in humans and nagana in cattle. Here we report the kinetic properties and sensitivity of recombinant enzyme to a range of lipophilic and classical antifolate drugs. The purified recombinant enzyme, expressed as a fusion protein with elongation factor Ts (Tsf) in ThyA- Escherichia coli, retains DHFR activity, but lacks any TS activity. TS activity was found to be extremely unstable (half-life of 28 s) following desalting of clarified bacterial lysates to remove small molecules. Stability could be improved 700-fold by inclusion of dUMP, but not by other pyrimidine or purine (deoxy)-nucleosides or nucleotides. Inclusion of dUMP during purification proved insufficient to prevent inactivation during the purification procedure. Methotrexate and trimetrexate were the most potent inhibitors of DHFR (Ki 0.1 and 0.6 nM, respectively) and FdUMP and nolatrexed of TS (Ki 14 and 39 nM, respectively). All inhibitors showed a marked drop-off in potency of 100- to 1,000-fold against trypanosomes grown in low folate medium lacking thymidine. The most potent inhibitors possessed a terminal glutamate moiety suggesting that transport or subsequent retention by polyglutamylation was important for biological activity. Supplementation of culture medium with folate markedly antagonised the potency of these folate-like inhibitors, as did thymidine in the case of the TS inhibitors raltitrexed and pemetrexed. PMID:27175479

  11. Novel Bifunctional Natriuretic Peptides as Potential Therapeutics*

    Science.gov (United States)

    Dickey, Deborah M.; Burnett, John C.; Potter, Lincoln R.

    2008-01-01

    Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797

  12. Novel bifunctional natriuretic peptides as potential therapeutics.

    Science.gov (United States)

    Dickey, Deborah M; Burnett, John C; Potter, Lincoln R

    2008-12-12

    Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797

  13. Robust Control of PEP Formation Rate in the Carbon Fixation Pathway of C4 Plants by a Bi-functional Enzyme

    Directory of Open Access Journals (Sweden)

    Hart Yuval

    2011-10-01

    Full Text Available Abstract Background C4 plants such as corn and sugarcane assimilate atmospheric CO2 into biomass by means of the C4 carbon fixation pathway. We asked how PEP formation rate, a key step in the carbon fixation pathway, might work at a precise rate, regulated by light, despite fluctuations in substrate and enzyme levels constituting and regulating this process. Results We present a putative mechanism for robustness in C4 carbon fixation, involving a key enzyme in the pathway, pyruvate orthophosphate dikinase (PPDK, which is regulated by a bifunctional enzyme, Regulatory Protein (RP. The robust mechanism is based on avidity of the bifunctional enzyme RP to its multimeric substrate PPDK, and on a product-inhibition feedback loop that couples the system output to the activity of the bifunctional regulator. The model provides an explanation for several unusual biochemical characteristics of the system and predicts that the system's output, phosphoenolpyruvate (PEP formation rate, is insensitive to fluctuations in enzyme levels (PPDK and RP, substrate levels (ATP and pyruvate and the catalytic rate of PPDK, while remaining sensitive to the system's input (light levels. Conclusions The presented PPDK mechanism is a new way to achieve robustness using product inhibition as a feedback loop on a bifunctional regulatory enzyme. This mechanism exhibits robustness to protein and metabolite levels as well as to catalytic rate changes. At the same time, the output of the system remains tuned to input levels.

  14. Bifunctional mesoporous silicas with clearly distinguished localization of grafted groups

    Science.gov (United States)

    Roik, N. V.; Belyakova, L. A.

    2013-12-01

    Bifunctional mesoporous silicas with clearly distinguished localization of grafted groups on the surface of particles and inside their pores were obtained by means of sol-gel synthesis with postsynthetic vapor-phase treatment in vacuum. It was found that the synthesized materials have the hexagonally ordered porous structure typical of MCM-41 type silica.

  15. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    International Nuclear Information System (INIS)

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe3O4/PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe3O4 nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10-3 S·cm-1. The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe3O4 NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  16. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    NARCIS (Netherlands)

    Zecevic, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan A.

    2015-01-01

    The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts(1-4). Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon source

  17. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Sheng, Shujuan; Ma, Qianli; Lv, Nan; Yu, Wensheng; Wang, Jinxian; Dong, Xiangting; Liu, Guixia, E-mail: wenshengyu2009@sina.com, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2016-03-15

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe{sub 3}O{sub 4}/PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe{sub 3}O{sub 4} nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10{sup -3} S·cm{sup -1}. The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe{sub 3}O{sub 4} NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  18. Active-site remodelling in the bifunctional fructose-1,6-bisphosphate aldolase/phosphatase.

    Science.gov (United States)

    Du, Juan; Say, Rafael F; Lü, Wei; Fuchs, Georg; Einsle, Oliver

    2011-10-27

    Fructose-1,6-bisphosphate (FBP) aldolase/phosphatase is a bifunctional, thermostable enzyme that catalyses two subsequent steps in gluconeogenesis in most archaea and in deeply branching bacterial lineages. It mediates the aldol condensation of heat-labile dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP) to FBP, as well as the subsequent, irreversible hydrolysis of the product to yield the stable fructose-6-phosphate (F6P) and inorganic phosphate; no reaction intermediates are released. Here we present a series of structural snapshots of the reaction that reveal a substantial remodelling of the active site through the movement of loop regions that create different catalytic functionalities at the same location. We have solved the three-dimensional structures of FBP aldolase/phosphatase from thermophilic Thermoproteus neutrophilus in a ligand-free state as well as in complex with the substrates DHAP and FBP and the product F6P to resolutions up to 1.3 Å. In conjunction with mutagenesis data, this pinpoints the residues required for the two reaction steps and shows that the sequential binding of additional Mg(2+) cations reversibly facilitates the reaction. FBP aldolase/phosphatase is an ancestral gluconeogenic enzyme optimized for high ambient temperatures, and our work resolves how consecutive structural rearrangements reorganize the catalytic centre of the protein to carry out two canonical reactions in a very non-canonical type of bifunctionality. PMID:21983965

  19. RNA Secondary Structure Modulates FMRP's Bi-Functional Role in the MicroRNA Pathway.

    Science.gov (United States)

    Kenny, Phillip; Ceman, Stephanie

    2016-01-01

    MicroRNAs act by post-transcriptionally regulating the gene expression of 30%-60% of mammalian genomes. MicroRNAs are key regulators in all cellular processes, though the mechanism by which the cell activates or represses microRNA-mediated translational regulation is poorly understood. In this review, we discuss the RNA binding protein Fragile X Mental Retardation Protein (FMRP) and its role in microRNA-mediated translational regulation. Historically, FMRP is known to function as a translational suppressor. However, emerging data suggests that FMRP has both an agonistic and antagonistic role in regulating microRNA-mediated translational suppression. This bi-functional role is dependent on FMRP's interaction with the RNA helicase Moloney leukemia virus 10 (MOV10), which modifies the structural landscape of bound mRNA, therefore facilitating or inhibiting its association with the RNA-Induced Silencing Complex. PMID:27338369

  20. The amino acid sequence of a 20 kDa bifunctional subtilisin/alpha-amylase inhibitor from bran [correction of brain] of rice (Oryza sativa L.) seeds.

    Science.gov (United States)

    Ohtsubo, K; Richardson, M

    1992-08-31

    A 20 kDa bifunctional inhibitor of the microbial proteinase, subtilisin, and the alpha-amylase from the larvae of the red flour beetle (Tribolium castaneum) was purified from bran of rice seeds by saline extraction, precipitation with ammonium sulphate, ion-exchange chromatography on DEAE-Cellulose and Toyopearl CM-650, and preparative HPLC on Vydac C18. The complete primary structure was determined by automatic degradation of the intact, reduced and S-alkylated protein, and by manual DABITC/PITC micro-sequencing of peptides obtained from the protein following separate enzymic digestions with trypsin, pepsin, chymotrypsin, elastase and the protease from S. aureus V8. The protein sequence, which contained 176 residues, showed strong homology with similar bifunctional inhibitors previously isolated from wheat and barley which are related to the Kunitz family of proteinase inhibitors from legume seeds. PMID:1511747

  1. Defective DNA cross-link removal in Chinese hamster cell mutants hypersensitive to bifunctional alkylating agents

    International Nuclear Information System (INIS)

    DNA repair-deficient mutants from five genetic complementation groups isolated previously from Chinese hamster cells were assayed for survival after exposure to the bifunctional alkylating agents mitomycin C or diepoxybutane. Groups 1, 3, and 5 exhibited 1.6- to 3-fold hypersensitivity compared to the wild-type cells, whereas Groups 2 and 4 exhibited extraordinary hypersensitivity. Mutants from Groups 1 and 2 were exposed to 22 other bifunctional alkylating agents in a rapid assay that compared cytotoxicity of the mutants to the wild-type parental strain, AA8. With all but two of the compounds, the Group 2 mutant (UV4) was 15- to 60-fold more sensitive than AA8 or the Group 1 mutant (UV5). UV4 showed only 6-fold hypersensitivity to quinacrine mustard. Alkaline elution measurements showed that this compound produced few DNA interstrand cross-links but numerous strand breaks. Therefore, the extreme hypersensitivity of mutants from Groups 2 and 4 appeared specific for compounds the main cytotoxic lesions of which were DNA cross-links. Mutant UV5 was only 1- to 4-fold hypersensitive to all the compounds. Although the initial number of cross-links was similar for the three cell lines, the efficiency of removal of cross-links was lowest in UV4 and intermediate in UV5. These results suggest that the different levels of sensitivity are specifically related to different efficiencies of DNA cross-link removal. The phenotype of hypersensitivity to both UV radiation and cross-link damage exhibited by the mutants in Groups 2 and 4 appears to differ from those of the known human DNA repair syndromes

  2. High performance bi-functional quantum cascade laser and detector

    Science.gov (United States)

    Schwarz, Benedikt; Ristanic, Daniela; Reininger, Peter; Zederbauer, Tobias; MacFarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried

    2015-08-01

    An improved bi-functional quantum cascade laser and detector emitting and detecting around 6.8 μ m is demonstrated. The design allows a significantly higher laser performance, showing that bi-functional designs can achieve a comparable pulsed performance to conventional quantum cascade lasers. In particular, the device has a threshold current density of 3 kA / cm 2 , an output power of 0.47 W , and a total wall-plug efficiency of 4.5% in pulsed mode. Optimized electron extraction and the prevention of thermal backfilling allow higher duty cycles, operation up to 10%, with 15 mW average output power at room temperature without optimization of the laser cavity or coatings. At zero bias, the device has a responsivity of around 40 mA / W and a noise equivalent power of 80 pW / √{ Hz } at room temperature, which in on-chip configuration outperforms conventional uncooled discrete detectors.

  3. Investigation of new bifunctional agents. D-Penicillamine

    International Nuclear Information System (INIS)

    Somatostatin inhibits the release of growth hormone (somatotropin) from the Anterior Pituitary. The main use of derivatives of somatostatin is to diagnose growth hormone problems and to use against some forms of cancer which involve growth hormone. Also somatostatin suppresses gastric acid secretion, gallbladder contractions, and pancreatic enzyme secretion. The aim of the current study is to investigate new bifunctional agents for labeling with 99mTc. Therefore D-Penicillamine was used as a bifunctional agent and compared to DTPA in the labeling with 99mTc. Quality controls were established using thin layer radio chromatography (TLRC) and electrophoresis techniques. In addition, high performance liquid radio chromatography (HPLRC) was also performed for elimination of possible uncertainties. The radiolabeled complexes maintained their stabilities throughout the study. The results obtained showed that 99mTc-D-Penicillamine-somatostatin is a promising potential radiopharmaceutical and an alternative of 99mTc-DTPA-somatostatin for in vivo and in vitro applications. (author)

  4. Experimental verifications on chemical carcinogenesis, a bifunctional alkylation between DNA interstrands

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is evidenced by the filter elution method that two carcinogenic aromatic hydrocarbons, benzo[a]pyrene and dibenzo[a,h]anthracene, two carcinogenic metal salts, beryllium chloride and cadmium chloride, four carcinogenic aromatic amines, 2-aminofluorene, β-naphthylamine, 4-aminobiphenyl and benzidine, can all induce DNA interstrand and DNA-protein cross-link in L1210 culture. However, under the same condition, the corresponding non-carcinogenic compounds, including benzo[k]fluorancene, anthracene, magnesium chloride, zinc chloride, a -naphthylamine, 2-aminobiphenyl and m-toluidine, cannot produce any cross-link adducts. All these results are consistent with the di-region theory that carcinogens are bio-bifunctional alkylation agents. This method can also be used to discriminate carcinogens and non-carcinogens.

  5. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    Science.gov (United States)

    Zečević, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan A.

    2016-01-01

    The ability to precisely control nanoscale features is increasingly exploited to develop and improve monofunctional catalysts1–4. Striking effects might also be expected in the case of bifunctional catalysts, which play an important role in hydrocracking of fossil and renewable hydrocarbon sources to provide high-quality diesel fuel5–7. Such bifunctional hydrocracking catalysts contain metal sites and acid sites, and for more than 50 years the so-called ‘intimacy criterion’8 has dictated the maximum distance between the two site types beyond which catalytic activity decreases. The lack of synthesis and material characterization methods with nanometer precision has long prevented in-depth exploration of the criterion, which has often been interpreted simply as ‘the closer the better’ for positioning metal and acid sites8–11. Here we show for a bifunctional catalyst, comprised of an intimate mixture of zeolite Y and alumina binder and with platinum (Pt) metal controllably deposited20,21 on either the zeolite or the binder, that close proximity between metal and zeolite acid sites can be detrimental: the selectivity when cracking large hydrocarbon feedstock molecules for high-quality diesel production is optimized with the catalyst that contains Pt on the binder, i.e. with a larger distance between metal and acid sites. Cracking of the large and complex hydrocarbon molecules typically derived from alternative sources such as gas-to-liquid technology, vegetable oil or algal oil6–7 should thus benefit especially from bifunctional catalysts that avoid locating Pt on the zeolite as the traditionally assumed optimal location. More generally, we anticipate that the ability to spatially organize different active sites at the nanoscale demonstrated here will benefit the further development and optimization of the newly emerging generation of multifunctional catalysts12–15. PMID:26659185

  6. Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

    Science.gov (United States)

    Zecevic, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan A.

    2015-12-01

    The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts. Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon sources to provide high-quality diesel fuel. Such bifunctional hydrocracking catalysts contain metal sites and acid sites, and for more than 50 years the so-called intimacy criterion has dictated the maximum distance between the two types of site, beyond which catalytic activity decreases. A lack of synthesis and material-characterization methods with nanometre precision has long prevented in-depth exploration of the intimacy criterion, which has often been interpreted simply as ‘the closer the better’ for positioning metal and acid sites. Here we show for a bifunctional catalyst—comprising an intimate mixture of zeolite Y and alumina binder, and with platinum metal controllably deposited on either the zeolite or the binder—that closest proximity between metal and zeolite acid sites can be detrimental. Specifically, the selectivity when cracking large hydrocarbon feedstock molecules for high-quality diesel production is optimized with the catalyst that contains platinum on the binder, that is, with a nanoscale rather than closest intimacy of the metal and acid sites. Thus, cracking of the large and complex hydrocarbon molecules that are typically derived from alternative sources, such as gas-to-liquid technology, vegetable oil or algal oil, should benefit especially from bifunctional catalysts that avoid locating platinum on the zeolite (the traditionally assumed optimal location). More generally, we anticipate that the ability demonstrated here to spatially organize different active sites at the nanoscale will benefit the further development and optimization of the emerging generation of multifunctional catalysts.

  7. A Novel Bifunctional Hybrid with Marine Bacterium Alkaline Phosphatase and Far Eastern Holothurian Mannan-Binding Lectin Activities

    OpenAIRE

    Larissa Balabanova; Vasily Golotin; Svetlana Kovalchuk; Alexander Bulgakov; Galina Likhatskaya; Oksana Son; Valery Rasskazov

    2014-01-01

    A fusion between the genes encoding the marine bacterium Cobetia marina alkaline phosphatase (CmAP) and Far Eastern holothurian Apostichopus japonicus mannan-binding C-type lectin (MBL-AJ) was performed. Expression of the fusion gene in E. coli cells resulted in yield of soluble recombinant chimeric protein CmAP/MBL-AJ with the high alkaline phosphatase activity and specificity of the lectin MBL-AJ. The bifunctional hybrid CmAP/MBL-AJ was produced as a dimer with the molecular mass of 200 kDa...

  8. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    International Nuclear Information System (INIS)

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N2 adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m2 g−1) and pore volume (0.016 cm3 g−1), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m2 g−1 and 0.701 cm3 g−1, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH2) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH2 bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds

  9. Bifunctional RNAs Targeting the Intronic Splicing Silencer N1 Increase SMN Levels and Reduce Disease Severity in an Animal Model of Spinal Muscular Atrophy

    OpenAIRE

    Osman, Erkan Y; Yen, Pei-Fen; Lorson, Christian L.

    2011-01-01

    Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of survival motor neuron-1 (SMN1). A nearly identical copy gene, SMN2, is present in all SMA patients. Although the SMN2 coding sequence has the potential to produce full-length SMN, nearly 90% of SMN2-derived transcripts are alternatively spliced and encode a truncated protein. SMN2, however, is an excellent therapeutic target. Previously, we developed antisense-based oligonucleotides (bifunctional RNAs) that specifi...

  10. Expression, purification, crystallization and preliminary X-ray analysis of eCGP123, an extremely stable monomeric green fluorescent protein with reversible photoswitching properties

    International Nuclear Information System (INIS)

    eCGP123, an extremely stable GFP with photoswitching properties, has been expressed, purified and crystallized. A diffraction data set has been collected at 2.10 Å resolution. Enhanced consensus green protein variant 123 (eCGP123) is an extremely thermostable green fluorescent protein (GFP) that exhibits useful negative reversible photoswitching properties. eCGP123 was derived by the application of both a consensus engineering approach and a recursive evolutionary process. Diffraction-quality crystals of recombinant eCGP123 were obtained by the hanging-drop vapour-diffusion method using PEG 3350 as the precipitant. The eCGP123 crystal diffracted X-rays to 2.10 Å resolution. The data were indexed in space group P1, with unit-cell parameters a = 74.63, b = 75.38, c = 84.51 Å, α = 90.96, β = 89.92, γ = 104.03°. The Matthews coefficient (VM = 2.26 Å3 Da−1) and a solvent content of 46% indicated that the asymmetric unit contained eight eCGP123 molecules

  11. Highly sensitive optical detection of specific protein in breast cancer cells using microstructured fiber in extremely low sample volume

    Science.gov (United States)

    Padmanabhan, Saraswathi; Shinoj, Vengalathunadakal K.; Murukeshan, Vadakke M.; Padmanabhan, Parasuraman

    2010-01-01

    A simple optical method using hollow-core photonic crystal fiber for protein detection has been described. In this study, estrogen receptor (ER) from a MCF-7 breast carcinoma cell lysates immobilized inside a hollow-core photonic crystal fiber was detected using anti-ER primary antibody with either Alexa™ Fluor 488 (green fluorescent dye) or 555 (red Fluorescent dye) labeled Goat anti-rabbit IgG as the secondary antibody. The fluorescence fingerprints of the ERα protein were observed under fluorescence microscope, and its optical characteristics were analyzed. The ERα protein detection by this proposed method is based on immuno binding from sample volume as low as 50 nL. This method is expected to offer great potential as a biosensor for medical diagnostics and therapeutics applications.

  12. Self-assembly of cobalt-centered metal organic framework and multiwalled carbon nanotubes hybrids as a highly active and corrosion-resistant bifunctional oxygen catalyst

    Science.gov (United States)

    Fang, Yiyun; Li, Xinzhe; Li, Feng; Lin, Xiaoqing; Tian, Min; Long, Xuefeng; An, Xingcai; Fu, Yan; Jin, Jun; Ma, Jiantai

    2016-09-01

    Metal organic frameworks (MOF) derived carbonaceous materials have emerged as promising bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts for electrochemical energy conversion and storage. But previous attempts to overcome the poor electrical conductivity of MOFs hybrids involve a harsh high-template pyrolytic process to in situ form carbon, which suffer from extremely complex operation and inevitable carbon corrosion at high positive potentials when OER is operated. Herein, a self-assembly approach is presented to synthesize a non-precious metal-based, high active and strong durable Co-MOF@CNTs bifunctional catalyst for OER and ORR. CNTs not only improve the transportation of the electrons but also can sustain the harsh oxidative environment of OER without carbon corrosion. Meanwhile, the unique 3D hierarchical structure offers a large surface area and stable anchoring sites for active centers and CNTs, which enables the superior durability of hybrid. Moreover, a synergistic catalysis of Co(II), organic ligands and CNTs will enhance the bifunctional electrocatalytic performance. Impressively, the hybrid exhibits comparable OER and ORR catalytic activity to RuO2 and 20 wt% Pt/C catalysts and superior stability. This facile and versatile strategy to fabricating MOF-based hybrids may be extended to other electrode materials for fuel cell and water splitting applications.

  13. Dimerization and Bifunctionality Confer Robustness to the Isocitrate Dehydrogenase Regulatory System in Escherichia coli*

    Science.gov (United States)

    Dexter, Joseph P.; Gunawardena, Jeremy

    2013-01-01

    An important goal of systems biology is to develop quantitative models that explain how specific molecular features give rise to systems-level properties. Metabolic and regulatory pathways that contain multifunctional proteins are especially interesting to study from this perspective because they have frequently been observed to exhibit robustness: the ability for a system to perform its proper function even as levels of its components change. In this study, we use extensive biochemical data and algebraic modeling to develop and analyze a model that shows how robust behavior arises in the isocitrate dehydrogenase (IDH) regulatory system of Escherichia coli, which was shown in 1985 to experimentally exhibit robustness. E. coli IDH is regulated by reversible phosphorylation catalyzed by the bifunctional isocitrate dehydrogenase kinase/phosphatase (IDHKP), and the level of IDH activity determines whether carbon flux is directed through the glyoxylate bypass (for growth on two-carbon substrates) or the full tricarboxylic acid cycle. Our model, which incorporates recent structural data on IDHKP, identifies several specific biochemical features of the system (including homodimerization of IDH and bifunctionality of IDHKP) that provide a potential explanation for robustness. Using algebraic techniques, we derive an invariant that summarizes the steady-state relationship between the phospho-forms of IDH. We use the invariant in combination with kinetic data on IDHKP to calculate IDH activity at a range of total IDH levels and find that our model predicts robustness. Our work unifies much of the known biochemistry of the IDH regulatory system into a single quantitative framework and highlights the importance of constructing biochemically realistic models in systems biology. PMID:23192354

  14. A PerR-like protein involved in response to oxidative stress in the extreme bacterium Deinococcus radiodurans

    International Nuclear Information System (INIS)

    Highlights: • We report a novel PerR-like protein of Fur family in D. radiodurans that is not annotated in the current database. • drperR responses to H2O2 and functions as a negative regulator of katE and dps. • We provided implications on how to utilize sequenced genome data and the importance of genome data mining. • This study adds knowledge to complicated regulatory network that responds to ROS stress in D. radiodurans. - Abstract: Response and defense systems against reactive oxygen species (ROS) contribute to the remarkable resistance of Deinococcus radiodurans to oxidative stress induced by oxidants or radiation. However, mechanisms involved in ROS response and defense systems of D. radiodurans are not well understood. Fur family proteins are important in ROS response. Only a single Fur homolog is predicted by sequence similarity in the current D. radiodurans genome database. Our bioinformatics analysis demonstrated an additional guanine nucleotide in the genome of D. radiodurans that is not in the database, leading to the discovery of another Fur homolog DrPerR. Gene disruption mutant of DrPerR showed enhanced resistance to hydrogen peroxide (H2O2) and increased catalase activity in cell extracts. Real-time PCR results indicated that DrPerR functions as a repressor of the catalase gene katE. Meanwhile, derepression of dps (DNA-binding proteins from starved cells) gene under H2O2 stress by DrPerR point to its regulatory role in metal ions hemostasis. Thus, DrPerR might function as a Fur homolog protein which is involved in ROS response and defense. These results help clarify the complicated regulatory network that responds to ROS stress in D. radiodurans

  15. A PerR-like protein involved in response to oxidative stress in the extreme bacterium Deinococcus radiodurans

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chengzhi; Wang, Liangyan; Li, Tao; Lin, Lin; Dai, Shang; Tian, Bing, E-mail: tianbing@zju.edu.cn; Hua, Yuejin, E-mail: yjhua@zju.edu.cn

    2014-07-18

    Highlights: • We report a novel PerR-like protein of Fur family in D. radiodurans that is not annotated in the current database. • drperR responses to H{sub 2}O{sub 2} and functions as a negative regulator of katE and dps. • We provided implications on how to utilize sequenced genome data and the importance of genome data mining. • This study adds knowledge to complicated regulatory network that responds to ROS stress in D. radiodurans. - Abstract: Response and defense systems against reactive oxygen species (ROS) contribute to the remarkable resistance of Deinococcus radiodurans to oxidative stress induced by oxidants or radiation. However, mechanisms involved in ROS response and defense systems of D. radiodurans are not well understood. Fur family proteins are important in ROS response. Only a single Fur homolog is predicted by sequence similarity in the current D. radiodurans genome database. Our bioinformatics analysis demonstrated an additional guanine nucleotide in the genome of D. radiodurans that is not in the database, leading to the discovery of another Fur homolog DrPerR. Gene disruption mutant of DrPerR showed enhanced resistance to hydrogen peroxide (H{sub 2}O{sub 2}) and increased catalase activity in cell extracts. Real-time PCR results indicated that DrPerR functions as a repressor of the catalase gene katE. Meanwhile, derepression of dps (DNA-binding proteins from starved cells) gene under H{sub 2}O{sub 2} stress by DrPerR point to its regulatory role in metal ions hemostasis. Thus, DrPerR might function as a Fur homolog protein which is involved in ROS response and defense. These results help clarify the complicated regulatory network that responds to ROS stress in D. radiodurans.

  16. Xpf and not the Fanconi anaemia proteins or Rev3 accounts for the extreme resistance to cisplatin in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Xiao-Yin Zhang

    2009-09-01

    Full Text Available Organisms like Dictyostelium discoideum, often referred to as DNA damage "extremophiles", can survive exposure to extremely high doses of radiation and DNA crosslinking agents. These agents form highly toxic DNA crosslinks that cause extensive DNA damage. However, little is known about how Dictyostelium and the other "extremophiles" can tolerate and repair such large numbers of DNA crosslinks. Here we describe a comprehensive genetic analysis of crosslink repair in Dictyostelium discoideum. We analyse three gene groups that are crucial for a replication-coupled repair process that removes DNA crosslinks in higher eukarya: The Fanconi anaemia pathway (FA, translesion synthesis (TLS, and nucleotide excision repair. Gene disruption studies unexpectedly reveal that the FA genes and the TLS enzyme Rev3 play minor roles in tolerance to crosslinks in Dictyostelium. However, disruption of the Xpf nuclease subcomponent results in striking hypersensitivity to crosslinks. Genetic interaction studies reveal that although Xpf functions with FA and TLS gene products, most Xpf mediated repair is independent of these two gene groups. These results suggest that Dictyostelium utilises a distinct Xpf nuclease-mediated repair process to remove crosslinked DNA. Other DNA damage-resistant organisms and chemoresistant cancer cells might adopt a similar strategy to develop resistance to DNA crosslinking agents.

  17. Structural analysis of a recombinant plant bifunctional nuclease TBN1

    Czech Academy of Sciences Publication Activity Database

    Kovaľ, Tomáš; Lipovová, P.; Podzimek, Tomáš; Matoušek, Jaroslav; Dušková, Jarmila; Skálová, Tereza; Štěpánková, Andrea; Hašek, Jindřich; Dohnálek, Jan

    Vol. no 1. Praha : Czech and Slovak Crystallographic Association, 2011. s. 29. ISSN 1211-5894. [Discussions in Structural Molecular Biology /9./. 24.03.2011-26.03.2011, Nové Hrady] R&D Projects: GA ČR GA202/06/0757; GA ČR GA310/09/1407; GA ČR GA521/09/1214 Grant ostatní: AVČR(CZ) Praemium Academiae Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z50510513; CEZ:AV0Z40500505 Keywords : bifunctional nuclease * cancer * x-ray analysis Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Bifunctional chelating agents for targeted α-particle radiotherapy

    International Nuclear Information System (INIS)

    An α-emitting radionuclide is proposed as a better choice for application in radiotherapy of either leukemias or lymphomas due to very high cytotoxicity, short emission path length, and immediate energy deposition minimizing collateral cytotoxicity. Metallic α-emitters that have been studied are 212Bi and 213Bi. Bifunctional derivatives of diethylenetriamine pentaacetic acid (DTPA) were found to form Bi(III) complexes that were labile in vivo. Pre-clinical experiments confirmed both the stability of the CHX-DTPA ligands for the Bi(III) isotopes and the therapeutic applicability of these α-emitting isotopes

  19. Association between arterial elasticity, C-reactive protein and maximal oxygen consumption in well-trained cadets during three days extreme physical load: a pilot study

    International Nuclear Information System (INIS)

    Regular aerobic training has beneficial effects on inflammatory pathways and on arterial elasticity, which are both important cardiovascular risk factors. The aim of the present study was to evaluate the effect of extreme physical load on arterial elasticity and inflammatory markers in well-trained healthy men who participated in a high-ranking combat course. Seven well-trained male cadets were examined during an international military combat course of 3.5 days duration. Small (C2) and large (C1) artery elasticity was assessed using diastolic pulse wave analysis. Inflammatory markers and arterial elasticity measurement were performed before and after the competition. The extreme prolonged physical load caused individually different responses in arterial elasticity, C-reactive protein (CRP) and creatine kinase in individual cadets. Maximal oxygen consumption (VO2 max kg−1) correlated significantly with the change (Δ-difference between baseline and 24 h recovery period) of creatine kinase (r = −0.78; p = 0.04) and ΔC2 (r = 0.78; p = 0.04) and ΔC1 (r = 0.82; p = 0.02). In multivariate analysis (R2 = 0.89, p = 0.01) the ΔC2 correlated strongly with VO2 max kg−1 (p = 0.005) and with the ΔCRP (p = 0.03), whereas the ΔC1 correlated only with VO2 max kg−1 and did not correlate significantly with the ΔCRP. Changes in small arterial elasticity induced by extreme physical load were significantly related to VO2 max kg−1 and ΔCRP, whereas the change of large artery elasticity was only associated with VO2 max kg−1. Our preliminary results indicate that acute exercise-induced inflammation may affect small artery elasticity. However, further, more extensive studies are needed in this area

  20. Improved homing of endothelial progenitor cells by the bispecific protein GPVI-CD133

    OpenAIRE

    Schönberger, T.; H. Langer; Gauß, A; Hafner, R; von der Ruhr, J; Schumm, M.; Bühring, HJ; van Zandvoort, M; Jung, G; Skutella, T.; Gawaz, M

    2011-01-01

    We designed a bifunctional protein, capable of capturing circulating endothelial progenitor cells to collagen-rich vascular lesions. The protein consists of the soluble platelet collagen receptor glycoprotein VI and an antibody to CD133. This construct substantially mediates EPC homing to vascular lesions. Furthermore, it augments reendothelialization of vascular lesions and reduces the extent of myocardial infarction. Therefore, this bifunctional protein could be a potential new therapeutic ...

  1. GST-TAT-SOD: Cell Permeable Bifunctional Antioxidant Enzyme-A Potential Selective Radioprotector.

    Science.gov (United States)

    Pan, Jianru; He, Huocong; Su, Ying; Zheng, Guangjin; Wu, Junxin; Liu, Shutao; Rao, Pingfan

    2016-01-01

    Superoxide dismutase (SOD) fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST), SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wild SOD had little radioprotective effect on irradiated L-02 and Hep G2 cells while amifostine was protective to both cell lines. SOD-TAT or GST-TAT-SOD pretreatment 3 h prior to radiation protects irradiated normal liver cells against radiation damage by eliminating intracellular excrescent superoxide, reducing cellular MDA level, enhancing cellular antioxidant ability and colony formation ability, and reducing apoptosis rate. Compared with SOD-TAT, GST-TAT-SOD was proved to have better protective effect on irradiated normal liver cells and minimal effect on irradiated hepatoma cells. Besides, GST-TAT-SOD was safe for normal cells and effectively transduced into different organs in mice, including the brain. The characteristics of this protein suggest that it may be a potential radioprotective agent in cancer therapy better than amifostine. Fusion of two antioxidant enzymes and cell-penetrating peptides is potentially valuable in the development of radioprotective agent. PMID:27313832

  2. GST-TAT-SOD: Cell Permeable Bifunctional Antioxidant Enzyme—A Potential Selective Radioprotector

    Science.gov (United States)

    Pan, Jianru; He, Huocong; Su, Ying; Zheng, Guangjin; Wu, Junxin; Liu, Shutao; Rao, Pingfan

    2016-01-01

    Superoxide dismutase (SOD) fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST), SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wild SOD had little radioprotective effect on irradiated L-02 and Hep G2 cells while amifostine was protective to both cell lines. SOD-TAT or GST-TAT-SOD pretreatment 3 h prior to radiation protects irradiated normal liver cells against radiation damage by eliminating intracellular excrescent superoxide, reducing cellular MDA level, enhancing cellular antioxidant ability and colony formation ability, and reducing apoptosis rate. Compared with SOD-TAT, GST-TAT-SOD was proved to have better protective effect on irradiated normal liver cells and minimal effect on irradiated hepatoma cells. Besides, GST-TAT-SOD was safe for normal cells and effectively transduced into different organs in mice, including the brain. The characteristics of this protein suggest that it may be a potential radioprotective agent in cancer therapy better than amifostine. Fusion of two antioxidant enzymes and cell-penetrating peptides is potentially valuable in the development of radioprotective agent. PMID:27313832

  3. GST-TAT-SOD: Cell Permeable Bifunctional Antioxidant Enzyme—A Potential Selective Radioprotector

    Directory of Open Access Journals (Sweden)

    Jianru Pan

    2016-01-01

    Full Text Available Superoxide dismutase (SOD fusion of TAT was proved to be radioprotective in our previous work. On that basis, a bifunctional recombinant protein which was the fusion of glutathione S-transferase (GST, SOD, and TAT was constructed and named GST-TAT-SOD. Herein we report the investigation of the cytotoxicity, cell-penetrating activity, and in vitro radioprotective effect of GST-TAT-SOD compared with wild SOD, single-function recombinant protein SOD-TAT, and amifostine. We demonstrated that wild SOD had little radioprotective effect on irradiated L-02 and Hep G2 cells while amifostine was protective to both cell lines. SOD-TAT or GST-TAT-SOD pretreatment 3 h prior to radiation protects irradiated normal liver cells against radiation damage by eliminating intracellular excrescent superoxide, reducing cellular MDA level, enhancing cellular antioxidant ability and colony formation ability, and reducing apoptosis rate. Compared with SOD-TAT, GST-TAT-SOD was proved to have better protective effect on irradiated normal liver cells and minimal effect on irradiated hepatoma cells. Besides, GST-TAT-SOD was safe for normal cells and effectively transduced into different organs in mice, including the brain. The characteristics of this protein suggest that it may be a potential radioprotective agent in cancer therapy better than amifostine. Fusion of two antioxidant enzymes and cell-penetrating peptides is potentially valuable in the development of radioprotective agent.

  4. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan

    2011-01-01

    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  5. Characterization of Multiple Heat-Shock Protein Transcripts from Cydia pomonella: Their Response to Extreme Temperature and Insecticide Exposure.

    Science.gov (United States)

    Yang, Xue-Qing; Zhang, Ya-Lin; Wang, Xiao-Qi; Dong, Hui; Gao, Ping; Jia, Ling-Yi

    2016-06-01

    The economically important fruit pest Cydia pomonella (L.) exhibits a strong adaptability and stress tolerance to environmental stresses. Heat-shock proteins (HSPs) play key roles in insects in coping with environmental stresses. However, little is known about the spatiotemporal expression patterns of HSPs and their response to stresses in C. pomonella. In this study, a thermal treatment-recovery test was performed, and the expression profiles of a novel isolated HSP, named CpHSP40, and six CpHSPs were determined. Third-instar larvae were able to recover from cold shock (0 °C) and heat shock (40 °C). Escherichia coli BL21 (DE3) cells harboring recombinant pET-28a (+)-CpHSP40 plasmid showed significant temperature tolerance. CpHSPs were developmentally and tissue-specifically expressed. The responses of CpHSPs to 0 and 40 °C (with or without recovery) and insecticide exposure were varied. All of these indicated that the expression of HSPs plays a role in the development and in environmental adaptation in C. pomonella. PMID:27159229

  6. Extreme Innovation

    OpenAIRE

    Sandmeier, Patricia; Gassmann, Oliver

    2006-01-01

    The article focuses on a study which examined the application of extreme programming methods to product innovation and development. Extreme programming is a process used in software engineering which deals with the fast changing customer requirements. The methodology used in the study is described. The study explored the challenges associated with product innovation structuring and management. The implications of the study findings for companies are highlighted.

  7. Protein expression and genetic structure of the coral Porites lobata in an environmentally extreme Samoan back reef: Does host genotype limit phenotypic plasticity?

    Science.gov (United States)

    Barshis, D.J.; Stillman, J.H.; Gates, R.D.; Toonen, R.J.; Smith, L.W.; Birkeland, C.

    2010-01-01

    The degree to which coral reef ecosystems will be impacted by global climate change depends on regional and local differences in corals' susceptibility and resilience to environmental stressors. Here, we present data from a reciprocal transplant experiment using the common reef building coral Porites lobata between a highly fluctuating back reef environment that reaches stressful daily extremes, and a more stable, neighbouring forereef. Protein biomarker analyses assessing physiological contributions to stress resistance showed evidence for both fixed and environmental influence on biomarker response. Fixed influences were strongest for ubiquitin-conjugated proteins with consistently higher levels found in back reef source colonies both pre and post-transplant when compared with their forereef conspecifics. Additionally, genetic comparisons of back reef and forereef populations revealed significant population structure of both the nuclear ribosomal and mitochondrial genomes of the coral host (FST = 0.146 P < 0.0001, FST = 0.335 P < 0.0001 for rDNA and mtDNA, respectively), whereas algal endosymbiont populations were genetically indistinguishable between the two sites. We propose that the genotype of the coral host may drive limitations to the physiological responses of these corals when faced with new environmental conditions. This result is important in understanding genotypic and environmental interactions in the coral algal symbiosis and how corals may respond to future environmental changes. ?? 2010 Blackwell Publishing Ltd.

  8. A Novel Bifunctional Hybrid with Marine Bacterium Alkaline Phosphatase and Far Eastern Holothurian Mannan-Binding Lectin Activities

    Science.gov (United States)

    Balabanova, Larissa; Golotin, Vasily; Kovalchuk, Svetlana; Bulgakov, Alexander; Likhatskaya, Galina; Son, Oksana; Rasskazov, Valery

    2014-01-01

    A fusion between the genes encoding the marine bacterium Cobetia marina alkaline phosphatase (CmAP) and Far Eastern holothurian Apostichopus japonicus mannan-binding C-type lectin (MBL-AJ) was performed. Expression of the fusion gene in E. coli cells resulted in yield of soluble recombinant chimeric protein CmAP/MBL-AJ with the high alkaline phosphatase activity and specificity of the lectin MBL-AJ. The bifunctional hybrid CmAP/MBL-AJ was produced as a dimer with the molecular mass of 200 kDa. The CmAP/MBL-AJ dimer model showed the two-subunit lectin part that is associated with two molecules of alkaline phosphatase functioning independently from each other. The highly active CmAP label genetically linked to MBL-AJ has advantaged the lectin-binding assay in its sensitivity and time. The double substitution A156N/F159K in the lectin domain of CmAP/MBL-AJ has enhanced its lectin activity by 25±5%. The bifunctional hybrid holothurian's lectin could be promising tool for developing non-invasive methods for biological markers assessment, particularly for improving the MBL-AJ-based method for early detection of a malignant condition in cervical specimens. PMID:25397876

  9. A novel bifunctional hybrid with marine bacterium alkaline phosphatase and Far Eastern holothurian mannan-binding lectin activities.

    Directory of Open Access Journals (Sweden)

    Larissa Balabanova

    Full Text Available A fusion between the genes encoding the marine bacterium Cobetia marina alkaline phosphatase (CmAP and Far Eastern holothurian Apostichopus japonicus mannan-binding C-type lectin (MBL-AJ was performed. Expression of the fusion gene in E. coli cells resulted in yield of soluble recombinant chimeric protein CmAP/MBL-AJ with the high alkaline phosphatase activity and specificity of the lectin MBL-AJ. The bifunctional hybrid CmAP/MBL-AJ was produced as a dimer with the molecular mass of 200 kDa. The CmAP/MBL-AJ dimer model showed the two-subunit lectin part that is associated with two molecules of alkaline phosphatase functioning independently from each other. The highly active CmAP label genetically linked to MBL-AJ has advantaged the lectin-binding assay in its sensitivity and time. The double substitution A156N/F159K in the lectin domain of CmAP/MBL-AJ has enhanced its lectin activity by 25 ± 5%. The bifunctional hybrid holothurian's lectin could be promising tool for developing non-invasive methods for biological markers assessment, particularly for improving the MBL-AJ-based method for early detection of a malignant condition in cervical specimens.

  10. Therapeutic potential of a non-steroidal bifunctional anti-inflammatory and anti-cholinergic agent against skin injury induced by sulfur mustard

    International Nuclear Information System (INIS)

    Sulfur mustard (bis(2-chloroethyl) sulfide, SM) is a highly reactive bifunctional alkylating agent inducing edema, inflammation, and the formation of fluid-filled blisters in the skin. Medical countermeasures against SM-induced cutaneous injury have yet to be established. In the present studies, we tested a novel, bifunctional anti-inflammatory prodrug (NDH 4338) designed to target cyclooxygenase 2 (COX2), an enzyme that generates inflammatory eicosanoids, and acetylcholinesterase, an enzyme mediating activation of cholinergic inflammatory pathways in a model of SM-induced skin injury. Adult SKH-1 hairless male mice were exposed to SM using a dorsal skin vapor cup model. NDH 4338 was applied topically to the skin 24, 48, and 72 h post-SM exposure. After 96 h, SM was found to induce skin injury characterized by edema, epidermal hyperplasia, loss of the differentiation marker, keratin 10 (K10), upregulation of the skin wound marker keratin 6 (K6), disruption of the basement membrane anchoring protein laminin 322, and increased expression of epidermal COX2. NDH 4338 post-treatment reduced SM-induced dermal edema and enhanced skin re-epithelialization. This was associated with a reduction in COX2 expression, increased K10 expression in the suprabasal epidermis, and reduced expression of K6. NDH 4338 also restored basement membrane integrity, as evidenced by continuous expression of laminin 332 at the dermal–epidermal junction. Taken together, these data indicate that a bifunctional anti-inflammatory prodrug stimulates repair of SM induced skin injury and may be useful as a medical countermeasure. - Highlights: • Bifunctional anti-inflammatory prodrug (NDH4338) tested on SM exposed mouse skin • The prodrug NDH4338 was designed to target COX2 and acetylcholinesterase. • The application of NDH4338 improved cutaneous wound repair after SM induced injury. • NDH4338 treatment demonstrated a reduction in COX2 expression on SM injured skin. • Changes of skin repair

  11. Therapeutic potential of a non-steroidal bifunctional anti-inflammatory and anti-cholinergic agent against skin injury induced by sulfur mustard

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yoke-Chen; Wang, James D.; Hahn, Rita A.; Gordon, Marion K.; Joseph, Laurie B. [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Heck, Diane E. [Department of Environmental Science, New York Medical College, Valhalla, NY (United States); Heindel, Ned D. [Department of Chemistry, Lehigh University, Bethlehem, PA (United States); Young, Sherri C. [Department of Chemistry, Muhlenberg College, Allentown, PA (United States); Sinko, Patrick J. [Department of Pharmaceutics, Rutgers University, Piscataway, NJ (United States); Casillas, Robert P. [MRIGlobal, Kansas City, MO (United States); Laskin, Jeffrey D. [Environmental and Occupational Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ (United States); Laskin, Debra L. [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Gerecke, Donald R., E-mail: gerecke@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States)

    2014-10-15

    Sulfur mustard (bis(2-chloroethyl) sulfide, SM) is a highly reactive bifunctional alkylating agent inducing edema, inflammation, and the formation of fluid-filled blisters in the skin. Medical countermeasures against SM-induced cutaneous injury have yet to be established. In the present studies, we tested a novel, bifunctional anti-inflammatory prodrug (NDH 4338) designed to target cyclooxygenase 2 (COX2), an enzyme that generates inflammatory eicosanoids, and acetylcholinesterase, an enzyme mediating activation of cholinergic inflammatory pathways in a model of SM-induced skin injury. Adult SKH-1 hairless male mice were exposed to SM using a dorsal skin vapor cup model. NDH 4338 was applied topically to the skin 24, 48, and 72 h post-SM exposure. After 96 h, SM was found to induce skin injury characterized by edema, epidermal hyperplasia, loss of the differentiation marker, keratin 10 (K10), upregulation of the skin wound marker keratin 6 (K6), disruption of the basement membrane anchoring protein laminin 322, and increased expression of epidermal COX2. NDH 4338 post-treatment reduced SM-induced dermal edema and enhanced skin re-epithelialization. This was associated with a reduction in COX2 expression, increased K10 expression in the suprabasal epidermis, and reduced expression of K6. NDH 4338 also restored basement membrane integrity, as evidenced by continuous expression of laminin 332 at the dermal–epidermal junction. Taken together, these data indicate that a bifunctional anti-inflammatory prodrug stimulates repair of SM induced skin injury and may be useful as a medical countermeasure. - Highlights: • Bifunctional anti-inflammatory prodrug (NDH4338) tested on SM exposed mouse skin • The prodrug NDH4338 was designed to target COX2 and acetylcholinesterase. • The application of NDH4338 improved cutaneous wound repair after SM induced injury. • NDH4338 treatment demonstrated a reduction in COX2 expression on SM injured skin. • Changes of skin repair

  12. RNA Secondary Structure Modulates FMRP’s Bi-Functional Role in the MicroRNA Pathway

    Directory of Open Access Journals (Sweden)

    Phillip Kenny

    2016-06-01

    Full Text Available MicroRNAs act by post-transcriptionally regulating the gene expression of 30%–60% of mammalian genomes. MicroRNAs are key regulators in all cellular processes, though the mechanism by which the cell activates or represses microRNA-mediated translational regulation is poorly understood. In this review, we discuss the RNA binding protein Fragile X Mental Retardation Protein (FMRP and its role in microRNA-mediated translational regulation. Historically, FMRP is known to function as a translational suppressor. However, emerging data suggests that FMRP has both an agonistic and antagonistic role in regulating microRNA-mediated translational suppression. This bi-functional role is dependent on FMRP’s interaction with the RNA helicase Moloney leukemia virus 10 (MOV10, which modifies the structural landscape of bound mRNA, therefore facilitating or inhibiting its association with the RNA-Induced Silencing Complex.

  13. Synthesis and Characterization of a New Bifunctional Dye Containing Spirobenzopyran and Cinnamoyl Moiety

    Institute of Scientific and Technical Information of China (English)

    申凯华; 崔东熏

    2005-01-01

    A novel bifunctional dye containing spirobenzopyran and cinnaznoyl moiety has been prepared and its photochromic behavior following irradiation at different wavelengths of monochrome UV light was investigated.The colourless bifunctional dye in film or solution exhibits unusual photochromism through structural and geometrical transformation from spirobenzopyran to merocyanine accompanying with photocrosslinking reaction in cinnamoyl moieties. Two kinds of photochemical reaction were achieved by irradiation at the different wavelengths of monochrome UV light (275 nm, 365 nm) selectively. The photochromic process of the bifunctional dye was discussed and the dynamic behaviors of the decolorization process were investigated.

  14. The structure of Aquifex aeolicus ribosomal protein S8 reveals a unique subdomain that contributes to an extremely tight association with 16S rRNA.

    Science.gov (United States)

    Menichelli, Elena; Edgcomb, Stephen P; Recht, Michael I; Williamson, James R

    2012-01-20

    The assembly of ribonucleoprotein complexes occurs under a broad range of conditions, but the principles that promote assembly and allow function at high temperature are poorly understood. The ribosomal protein S8 from Aquifex aeolicus (AS8) is unique in that there is a 41-residue insertion in the consensus S8 sequence. In addition, AS8 exhibits an unusually high affinity for the 16S ribosomal RNA, characterized by a picomolar dissociation constant that is approximately 26,000-fold tighter than the equivalent interaction from Escherichia coli. Deletion analysis demonstrated that binding to the minimal site on helix 21 occurred at the same nanomolar affinity found for other bacterial species. The additional affinity required the presence of a three-helix junction between helices 20, 21, and 22. The crystal structure of AS8 was solved, revealing the helix-loop-helix geometry of the unique AS8 insertion region, while the core of the molecule is conserved with known S8 structures. The AS8 structure was modeled onto the structure of the 30S ribosomal subunit from E. coli, suggesting the possibility that the unique subdomain provides additional backbone and side-chain contacts between the protein and an unpaired base within the three-way junction of helices 20, 21, and 22. Point mutations in the protein insertion subdomain resulted in a significantly reduced RNA binding affinity with respect to wild-type AS8. These results indicate that the AS8-specific subdomain provides additional interactions with the three-way junction that contribute to the extremely tight binding to ribosomal RNA. PMID:22079365

  15. The Mycobacterium tuberculosis Rv2540c DNA sequence encodes a bifunctional chorismate synthase

    Directory of Open Access Journals (Sweden)

    Santos Diógenes S

    2008-04-01

    Full Text Available Abstract Background The emergence of multi- and extensively-drug resistant Mycobacterium tuberculosis strains has created an urgent need for new agents to treat tuberculosis (TB. The enzymes of shikimate pathway are attractive targets to the development of antitubercular agents because it is essential for M. tuberculosis and is absent from humans. Chorismate synthase (CS is the seventh enzyme of this route and catalyzes the NADH- and FMN-dependent synthesis of chorismate, a precursor of aromatic amino acids, naphthoquinones, menaquinones, and mycobactins. Although the M. tuberculosis Rv2540c (aroF sequence has been annotated to encode a chorismate synthase, there has been no report on its correct assignment and functional characterization of its protein product. Results In the present work, we describe DNA amplification of aroF-encoded CS from M. tuberculosis (MtCS, molecular cloning, protein expression, and purification to homogeneity. N-terminal amino acid sequencing, mass spectrometry and gel filtration chromatography were employed to determine identity, subunit molecular weight and oligomeric state in solution of homogeneous recombinant MtCS. The bifunctionality of MtCS was determined by measurements of both chorismate synthase and NADH:FMN oxidoreductase activities. The flavin reductase activity was characterized, showing the existence of a complex between FMNox and MtCS. FMNox and NADH equilibrium binding was measured. Primary deuterium, solvent and multiple kinetic isotope effects are described and suggest distinct steps for hydride and proton transfers, with the former being more rate-limiting. Conclusion This is the first report showing that a bacterial CS is bifunctional. Primary deuterium kinetic isotope effects show that C4-proS hydrogen is being transferred during the reduction of FMNox by NADH and that hydride transfer contributes significantly to the rate-limiting step of FMN reduction reaction. Solvent kinetic isotope effects and

  16. Crystallization of recombinant bifunctional nuclease TBN1 from tomato

    International Nuclear Information System (INIS)

    Glycosylated recombinant bifunctional nuclease from tomato has been crystallized and preliminary X-ray diffraction analysis was performed. The endonuclease TBN1 from Solanum lycopersicum (tomato) was expressed in Nicotiana benthamiana leaves and purified with suitable quality and in suitable quantities for crystallization experiments. Two crystal forms (orthorhombic and rhombohedral) were obtained and X-ray diffraction experiments were performed. The presence of natively bound Zn2+ ions was confirmed by X-ray fluorescence and by an absorption-edge scan. X-ray diffraction data were collected from the orthorhombic (resolution of 5.2 Å) and rhombohedral (best resolution of 3.2 Å) crystal forms. SAD, MAD and MR methods were applied for solution of the phase problem, with partial success. TBN1 contains three Zn2+ ions in a similar spatial arrangement to that observed in nuclease P1 from Penicillium citrinum

  17. Chemoselective Reactivity of Bifunctional Cyclooctynes on Si(001)

    CERN Document Server

    Reutzel, Marcel; Lipponer, Marcus A; Länger, Christian; Höfer, Ulrich; Koert, Ulrich; Dürr, Michael

    2016-01-01

    Controlled organic functionalization of silicon surfaces as integral part of semiconductor technology offers new perspectives for a wide range of applications. The high reactivity of the silicon dangling bonds, however, presents a major hindrance for the first basic reaction step of such a functionalization, i.e., the chemoselective attachment of bifunctional organic molecules on the pristine silicon surface. We overcome this problem by employing cyclooctyne as the major building block of our strategy. Functionalized cyclooctynes are shown to react on Si(001) selectively via the strained cyclooctyne triple bond while leaving the side groups intact. The achieved selectivity originates from the distinctly different adsorption dynamics of the separate functionalities: A direct adsorption pathway is demonstrated for cyclooctyne as opposed to the vast majority of other organic functional groups. The latter ones react on Si(001) via a metastable intermediate which makes them effectively unreactive in competition wi...

  18. Bifunctional chelates of RH-105 and AU199 as potential radiotherapeutic agents

    Energy Technology Data Exchange (ETDEWEB)

    Droege, P.

    1997-03-01

    Research is presented on new bifunctional chelating ligand systems with stability on the macroscopic and radiochemical levels. The synthesis of the following complexes are described: rhodium 105, palladium 109, and gold 198.

  19. Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

    Science.gov (United States)

    Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

    2003-10-21

    There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

  20. The onset of the progression of acute phase response mechanisms induced by extreme impacts can be followed by the decrease in blood levels of positive acute phase proteins.

    Science.gov (United States)

    Larina, Olga; Bekker, Anna

    Studies performed at space flights and earth-based simulation models detected the plasma indices of acute phase reaction (APR), i.e. the increase of APR cytokine mediators and alterations in the production of blood acute phase proteins (APP) at the initial stages of adaptation to altered gravity conditions. Acute phase response is the principal constituent of the functional activity of innate immunity system. Changes in plasma APPs contents are considered to serve the restoration of homeostasis state. According to trends of their concentration shifts at the evolving of acute phase reaction APPs are denoted as positive, neutral, or negative. Plasma concentrations of positive acute phase proteins α1-acid glycoprotein (α1-AGP), α1-antitrypsin (α1-AT), and neutral α2-macroglobulin (α2-M) were measured in human study at 12-hour antiorthostatic position (AOP) with 15° head down tilt and hypoxia experiments at 14% oxygen in pressure chamber. Both of these impacts were shown to produce alterations in the APP levels indicative for acute phase response. Nevertheless, in AOP experiment noticeable decrease in α1-AGP concentration occurred by hour 12, and even more pronounced decline of α1-AGP and α1-AT were found on hypoxia hours 12 and 36. Acute phase proteins α1-AGP and α2-M possess the features of proteinase inhibitors. This function is implemented by the formation of complexes with the molecules of proteolytic enzymes which subsequently are removed from the blood flow. Transient decrease in plasma concentrations of protease inhibitors on early phases of APR development was reported to result from the growth of plasma protease activity due to cathepsin release from activated leukocytes, which had not yet been compensated by enhanced APP synthesis. Being a carrier protein for positively charged and neutral substances, α1-AGP shows pronounced elevation in its blood content during APR development. As assumed, it is required for the transportation of the increased

  1. Novel 16-substituted bifunctional derivatives of huperzine B: multifunctional cholinesterase inhibitors

    OpenAIRE

    Shi, Yu-fang; Zhang, Hai-Yan; Wang, Wei; Fu, Yan; Xia, Yu; Tang, Xi-can; Bai, Dong-lu; He, Xu-chang

    2009-01-01

    Aim: To design novel bifunctional derivatives of huperzine B (HupB) based on the concept of dual binding site of acetylcholinesterase (AChE) and evaluate their pharmacological activities for seeking new drug candidates against Alzheimer's disease (AD). Methods: Novel 16-substituted bifunctional derivatives of HupB were synthesized through chemical reactions. The inhibitory activities of the derivatives toward AChE and butyrylcholinesterase (BuChE) were determined in vitro by modified Ellman's...

  2. Bifunctional Pt-Si Alloys for Small Organic Molecule Electro-oxidation

    DEFF Research Database (Denmark)

    Permyakova, Anastasia Aleksandrovna; Suntivich, Jin; Han, Binghong;

    bifunctional requirement, which demands both adsorption and water oxidation sites. In this contribution, we explore the possibility of using Pt-Si alloys to fulfill this bifunctional requirement. Silicon, a highly oxophillic element, is alloyed into Pt as a site for water oxidation, while Pt serves as a CO...... adsorption site. We will discuss the enhanced activity of Pt-Si alloys for small organic molecule oxidation, which can be attributed to the improved CO electro-oxidation kinetics on Pt-Si....

  3. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kai; Ma, Chun–Fang; Ling, Yuan; Li, Meng [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Gao, Qiang, E-mail: gaoqiang@cug.edu.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Luo, Wen–Jun, E-mail: heartnohome@yahoo.com.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2015-07-15

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N{sub 2} adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m{sup 2} g{sup −1}) and pore volume (0.016 cm{sup 3} g{sup −1}), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m{sup 2} g{sup −1} and 0.701 cm{sup 3} g{sup −1}, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH{sub 2}) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH{sub 2} bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds.

  4. NHS-MAS3: a bifunctional chelator alternative to NHS-MAG3

    International Nuclear Information System (INIS)

    This laboratory uses an N-hydroxysuccinimide derivative of S-acetylmercaptoacetyltriglycine (NHS-MAG3) to conjugate amines for subsequent labeling with 99mTc. However, the synthesis from triglycerine is general and not restricted to this tripeptide. We had earlier selected a small number of alternative tripeptides and synthesized the corresponding NHS derivatives. Each was then evaluated in a search for bifunctional chelators with properties superior to NHS-MAG3, such as lower serum protein binding or improved stability to cysteine challenge. Based on these preliminary results, NHS-S-acetylmercaptoacetyltriserine (NHS-MAS3) was selected for further investigation. We have now conjugated this bifunctional chelator to biocytin and to an amine-derivatized peptide nucleic acid (PNA). Both carriers were also conjugated with NHS-MAG3 under identical conditions and all were labeled with 99mTc at neutral pH and at boiling temperature while the conjugated PNAs were radiolabelled at neutral pH and at room temperature. Regardless of the chelator, reverse phase HPLC radiochromatograms of the labeled biotins and PNAs after purification showed a single peak. However, by size exclusion HPLC, the radiochromatograms always showed several peaks even after purification, but the MAS3 radiochromatograms were less complicated. For biotin and PNA both, radiolabeling via MAS3 showed improved 99mTc stability in 37 deg. C serum and in cysteine solution. The four preparations were administered to mice implanted in one thigh with avidin beads (biotins) or complementary PNA beads (PNAs). At 5 h post-administration, no significant differences were observed in the targeting of PNA beads between the two chelators, however the target thigh/normal thigh ratio was significantly higher for MAS3-biotin compared to MAG3-biotin. We conclude that labeling biocytin and amine-derivatized PNA with NHS-MAS3 compared to NHS-MAG3 provides simpler radiochromatographic profiles, improved stability of the label in

  5. Hypoxia targeted bifunctional suicide gene expression enhances radiotherapy in vitro and in vivo

    International Nuclear Information System (INIS)

    Purpose: To investigate whether hypoxia targeted bifunctional suicide gene expression-cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT) with 5-FC treatments can enhance radiotherapy. Materials and methods: Stable transfectants of R3327-AT cells were established which express a triple-fusion-gene: CD, UPRT and monomoric DsRed (mDsRed) controlled by a hypoxia inducible promoter. Hypoxia-induced expression/function of CDUPRTmDsRed was verified by western blot, flow cytometry, fluorescent microscopy, and cytotoxicity assay of 5-FU and 5-FC. Tumor-bearing mice were treated with 5-FC and local radiation. Tumor volume was monitored and compared with those treated with 5-FC or radiation alone. In addition, the CDUPRTmDsRed distribution in hypoxic regions of tumor sections was visualized with fluorescent microscopy. Results: Hypoxic induction of CDUPRTmDsRed protein correlated with increased sensitivity to 5-FC and 5-FU. Significant radiosensitization effects were detected after 5-FC treatments under hypoxic conditions. In the tumor xenografts, the distribution of CDUPRTmDsRed expression visualized with fluorescence microscopy was co-localized with the hypoxia marker pimonidazole positive staining cells. Furthermore, administration of 5-FC to mice in combination with local irradiation resulted in significant tumor regression, as in comparison with 5-FC or radiation treatments alone. Conclusions: Our data suggest that the hypoxia-inducible CDUPRT/5-FC gene therapy strategy has the ability to specifically target hypoxic cancer cells and significantly improve the tumor control in combination with radiotherapy.

  6. The bifunctional dihydrofolate reductase thymidylate synthase of Tetrahymena thermophila provides a tool for molecular and biotechnology applications

    Directory of Open Access Journals (Sweden)

    Tiedtke Arno

    2006-03-01

    Full Text Available Abstract Background Dihydrofolate reductase (DHFR and thymidylate synthase (TS are crucial enzymes in DNA synthesis. In alveolata both enzymes are expressed as one bifunctional enzyme. Results Loss of this essential enzyme activities after successful allelic assortment of knock out alleles yields an auxotrophic marker in ciliates. Here the cloning, characterisation and functional analysis of Tetrahymena thermophila's DHFR-TS is presented. A first aspect of the presented work relates to destruction of DHFR-TS enzyme function in an alveolate thereby causing an auxotrophy for thymidine. A second aspect is to knock in an expression cassette encoding for a foreign gene with subsequent expression of the target protein. Conclusion This system avoids the use of antibiotics or other drugs and therefore is of high interest for biotechnological applications.

  7. Synthesis and evaluation of a new bifunctional NETA chelate for molecular targeted radiotherapy using90Y or177Lu

    International Nuclear Information System (INIS)

    Introduction: Therapeutic potential of β-emitting cytotoxic radionuclides 90Y and 177Lu has been demonstrated in numerous preclinical and clinical trials. A bifunctional chelate that can effectively complex with the radioisotopes is a critical component for molecular targeted radiotherapy 90Y and 177Lu. A new bifunctional chelate 5p-C-NETA with a relatively long alkyl spacer between the chelating backbone and the functional unit for conjugation to a tumor targeting moiety was synthesized. 5p-C-NETA was conjugated to a model targeting moiety, a cyclic Arg-Gly-Asp-D-Tyr-Lys (RGDyK) peptide binding integrin αvβ3 protein overexpressed on various cancers. 5p-C-NETA was conjugated to c(RGDyK) peptide and evaluated for potential use in molecular targeted radiotherapy of 90Y and 177Lu. Methods: 5p-C-NETA conjugated with c(RGDyK) was evaluated in vitro for radiolabeling, serum stability, binding affinity, and the result of the in vitro studies of 5p-C-NETA-c(RGDyK) was compared to that of 3p-C-NETA-c(RGDyK). 177Lu-5p-C-NETA-c(RGDyK) was further evaluated for in vivo biodistribution using gliobastoma bearing mice. Result: The new chelate rapidly and tightly bound to a cytotoxic radioisotope for cancer therapy, 90Y or 177Lu with excellent radiolabeling efficiency and maximum specific activity under mild condition (> 99%, RT, < 1 min). 90Y- and 177Lu-radiolabeled complexes of the new chelator remained stable in human serum without any loss of the radiolanthanide for 14 days. Introduction of the tumor targeting RGD moiety to the new chelator made little impact on complexation kinetics and stability with 90Y or 177Lu. 177Lu-radiolabeled 5p-C-NETA-c(RGDyK) conjugate was shown to target tumors in mice and produced a favorable in vivo stability profile. Conclusion: The results of in vitro and in vivo evaluation suggest that 5p-C-NETA is an effective bifunctional chelate of 90Y and 177Lu that can be applied for generation of versatile molecular targeted radiopharmaceuticals

  8. Molecular Dynamics of an Extremely Thermophilic Ribose Binding Protein%分子动力学模拟极端嗜热核糖结合蛋白的热力学稳定性

    Institute of Scientific and Technical Information of China (English)

    冯献礼; 赵熹; 于辉; 王乙博; 孙铁东; 黄旭日

    2012-01-01

    Molecular dynamics simulations for extremely thermophilic protein thermoanaerobacter teng- congensis ribose binding protein (tteRBP) were performed to investigate the thermophilic mechanism of the protein. The comparative analysis of molecular trajectories of room temperature (300 K) and optimal activity temperature (375 K) shows that the protein conformations are stably maintained, but the concerted motions are different. The flexibility of the protein at 375 K significantly increases, so the protein can adjust the local conformation to adapt to extreme temperature. The analysis of the changes in protein structure confirmed that the local conformation adjustment at 375 K olavs a key role on the extreme hizh temoerature stability.%采用分子动力学模拟方法研究极端嗜热性核糖结合蛋白(tteRBP)的嗜热机理.在常温(300 K)和最佳活性温度(375 K)时,分别对tteRBP分子进行动力学模拟,结果表明,整体分子均保持结构稳定,但分子内部的协调运动不同.在375 K时蛋白整体柔性显著提高,使分子能够局部调整构象以适应极端高温.蛋白结构变化的分析也确认了高温时构象局部微调对蛋白极端高温稳定性的关键作用.

  9. Magnetic-plasmonic bifunctional CoO–Ag heterostructure nanoparticles

    International Nuclear Information System (INIS)

    We demonstrate the synthesis of CoO–Ag heterostructure nanoparticles by chemical reduction of AgNO3 in the presence of Co nanoparticles in oleylamine (OAm). OAm plays multiple roles as a surfactant, solvent, and reducing agent. The mechanism of surface-activated heterogeneous nucleation and growth on the preformed seeds has been proposed. At the same time, the Co nanoparticles are oxidized to form hollow CoO nanoparticles through the Kirkendall effect. The resulting CoO–Ag heterostructures display mushroom-like morphology, Ag nanoparticle as ‘cap’ attached on the ‘stem’ of hollow CoO nanoparticles. The size of Ag domains in the heterostructure nanoparticles can be tuned by controlling the volume of Co nanoparticles. The plasmonic absorption and the magnetization of the bifunctional nanoparticles were investigated. The combination of the hollow structure of the CoO and the surface plasmon resonances of the Ag domains may make them suitable for catalysis, drug delivery, therapy, and surface-enhanced Raman scattering. (papers)

  10. Gold(I) catalysts with bifunctional P, N ligands.

    Science.gov (United States)

    Wetzel, Corinna; Kunz, Peter C; Thiel, Indre; Spingler, Bernhard

    2011-08-15

    A series of phosphanes with imidazolyl substituents were prepared as hemilabile PN ligands. The corresponding gold(I) complexes were tested as bifunctional catalysts in the Markovnikov hydration of 1-octyne, as well as in the synthesis of propargylamines by the three component coupling reaction of piperidine, benzaldehyde, and phenylacetylene. While the activity in the hydration of 1-octyne was low, the complexes are potent catalysts for the three component coupling reaction. In homogeneous solution the conversions to the respective propargylamine were considerably higher than under aqueous biphasic conditions. The connectivity of the imidazolyl substituents to the phosphorus atom, their substitution pattern, as well as the number of heteroaromatic substituents have pronounced effects on the catalytic activity of the corresponding gold(I) complexes. Furthermore, formation of polymetallic species with Au(2), Au(3), and Au(4) units has been observed and the solid-state structures of the compounds [(5)(2)Au(3)Cl(2)]Cl and [(3c)(2)Au(4)Cl(2)]Cl(2) (3c = tris(2-isopropylimidazol-4(5)-yl phosphane, 5 = 2-tert-butylimidazol-4(5)-yldiphenyl phosphane) were determined. The gold(I) complexes of imidazol-2-yl phosphane ligands proved to be a novel source for bis(NHC)gold(I) complexes (NHC = N-heterocyclic carbene). PMID:21761834

  11. Gold-Copper Nanoparticles: Nanostructural Evolution and Bifunctional Catalytic Sites

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jun; Shan, Shiyao; Yang, Lefu; Mott, Derrick; Malis, Oana; Petkov, Valeri; Cai, Fan; Ng, Mei; Luo, Jin; Chen, Bing H.; Engelhard, Mark H.; Zhong, Chuan-Jian

    2012-12-12

    Understanding of the atomic-scale structure is essential for exploiting the unique catalytic properties of any nanoalloy catalyst. This report describes novel findings of an investigation of the nanoscale alloying of gold-copper (AuCu) nanoparticles and its impact on the surface catalytic functions. Two pathways have been explored for the formation of AuCu nanoparticles of different compositons, including wet chemical synthesis from mixed Au- and Cu-precursor molecules, and nanoscale alloying via an evolution of mixed Au- and Cu-precursor nanoparticles near the nanoscale melting temperatures. For the evolution of mixed precursor nanoparticles, synchrotron x-ray based in-situ real time XRD was used to monitor the structural changes, revealing nanoscale alloying and reshaping towards an fcc-type nanoalloy (particle or cube) via a partial melting–resolidification mechanism. The nanoalloys supported on carbon or silica were characterized by in-situ high-energy XRD/PDFs, revealing an intriguing lattice "expanding-shrinking" phenomenon depending on whether the catalyst is thermochemically processed under oxidative or reductive atmosphere. This type of controllable structural changes is found to play an important role in determining the catalytic activity of the catalysts for carbon monoxide oxidation reaction. The tunable catalytic activities of the nanoalloys under thermochemically oxidative and reductive atmospheres are also discussed in terms of the bifunctional sites and the surface oxygenated metal species for carbon monoxide and oxygen activation.

  12. Novel Polyamide Proton Exchange Membranes with Bi-Functional Sulfonimide Bridges for Fuel Cell Applications

    International Nuclear Information System (INIS)

    Graphical abstract: A polymer proton conductor crosslinked with bi-functional sulfonamide bridges is synthesized for PEM fuel cell applications. The architecture simultaneously enhances mechanical strength and improves water retention of the PEMs. With an appropriate degree of crosslinking, the bi-functional PEM exhibits comparable performance to that of a commercial Nafion membrane tested in a direct methanol fuel cell. - Abstract: We design and successfully synthesize non-fluorinated polyamides with controlled crosslinking using sulfonimide as a bi-functional linker to interconnect polymer backbones and as a bridge for proton conduction. We show that the bi-functional linkers are highly beneficial not only for mechanical enforcement of the proton exchange membranes but also for enhancement of water retention capacity. With an appropriate degree of crosslinking, higher water retention capacity than that of commercial Nafion membranes can be obtained. The maximum proton conductivity of the membranes is found to be as high as 0.139 S cm−1 at 80 °C, almost the same as that of a Nafion 117 membrane. Excellent performance with the bi-functional polymer membranes in an air-breathing direct methanol fuel cell prototype, comparable to the performance of a Nafion 117 membrane, is demonstrated

  13. Mechanish of dTTP Inhibition of the Bifunctional dCTP Deaminase:dUTPase Encoded by Mycobacterium tuberculosis

    DEFF Research Database (Denmark)

    Helt, Signe Smedegaard; Thymark, Majbritt; Harris, Pernille;

    2008-01-01

    Recombinant deoxycytidine triphosphate (dCTP) deaminase from Mycobacterium tuberculosis was produced in Escherichia coli and purified. The enzyme proved to be a bifunctional dCTP deaminase:deoxyuridine triphosphatase. As such, the M. tuberculosis enzyme is the second bifunctional enzyme to be cha...

  14. Biochemical Properties and Biological Function of a Monofunctional Microbial Biotin Protein Ligase

    OpenAIRE

    Daniels, Kyle G.; Beckett, Dorothy

    2010-01-01

    Biotin protein ligases constitute a family of enzymes that catalyze biotin linkage to biotin-dependent carboxylases. In bacteria these enzymes are functionally divided into two classes; the monofunctional enzymes that only catalyze biotin addition and the bifunctional enzymes that also bind to DNA to regulate transcription initiation. Biochemical and biophysical studies of the bifunctional Escherichia coli ligase suggest that several properties of the enzyme have evolved to support its additi...

  15. Crystal structure of the karyopherin Kap121p bound to the extreme C-terminus of the protein phosphatase Cdc14p

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Junya [Division of Biological Science, Graduate School of Science, Nagoya University (Japan); Hirano, Hidemi [Division of Biological Science, Graduate School of Science, Nagoya University (Japan); Structural Biology Research Center, Graduate School of Science, Nagoya University (Japan); Matsuura, Yoshiyuki, E-mail: matsuura.yoshiyuki@d.mbox.nagoya-u.ac.jp [Division of Biological Science, Graduate School of Science, Nagoya University (Japan); Structural Biology Research Center, Graduate School of Science, Nagoya University (Japan)

    2015-07-31

    In Saccharomyces cerevisiae, the protein phosphatase Cdc14p is an antagonist of mitotic cyclin-dependent kinases and is a key regulator of late mitotic events such as chromosome segregation, spindle disassembly and cytokinesis. The activity of Cdc14p is controlled by cell-cycle dependent changes in its association with its competitive inhibitor Net1p (also known as Cfi1p) in the nucleolus. For most of the cell cycle up to metaphase, Cdc14p is sequestered in the nucleolus in an inactive state. During anaphase, Cdc14p is released from Net1p, spreads into the nucleus and cytoplasm, and dephosphorylates key mitotic targets. Although regulated nucleocytoplasmic shuttling of Cdc14p has been suggested to be important for exit from mitosis, the mechanism underlying Cdc14p nuclear trafficking remains poorly understood. Here we show that the C-terminal region (residues 517–551) of Cdc14p can function as a nuclear localization signal (NLS) in vivo and also binds to Kap121p (also known as Pse1p), an essential nuclear import carrier in yeast, in a Gsp1p-GTP-dependent manner in vitro. Moreover we report a crystal structure, at 2.4 Å resolution, of Kap121p bound to the C-terminal region of Cdc14p. The structure and structure-based mutational analyses suggest that either the last five residues at the extreme C-terminus of Cdc14p (residues 547–551; Gly-Ser-Ile-Lys-Lys) or adjacent residues with similar sequence (residues 540–544; Gly-Gly-Ile-Arg-Lys) can bind to the NLS-binding site of Kap121p, with two residues (Ile in the middle and Lys at the end of the five residues) of Cdc14p making key contributions to the binding specificity. Based on comparison with other structures of Kap121p-ligand complexes, we propose “IK-NLS” as an appropriate term to refer to the Kap121p-specific NLS. - Highlights: • The C-terminus of Cdc14p binds to Kap121p in a Gsp1p-GTP-dependent manner. • The crystal structure of Kap121p-Cdc14p complex is determined. • The structure reveals how

  16. Crystal structure of the karyopherin Kap121p bound to the extreme C-terminus of the protein phosphatase Cdc14p

    International Nuclear Information System (INIS)

    In Saccharomyces cerevisiae, the protein phosphatase Cdc14p is an antagonist of mitotic cyclin-dependent kinases and is a key regulator of late mitotic events such as chromosome segregation, spindle disassembly and cytokinesis. The activity of Cdc14p is controlled by cell-cycle dependent changes in its association with its competitive inhibitor Net1p (also known as Cfi1p) in the nucleolus. For most of the cell cycle up to metaphase, Cdc14p is sequestered in the nucleolus in an inactive state. During anaphase, Cdc14p is released from Net1p, spreads into the nucleus and cytoplasm, and dephosphorylates key mitotic targets. Although regulated nucleocytoplasmic shuttling of Cdc14p has been suggested to be important for exit from mitosis, the mechanism underlying Cdc14p nuclear trafficking remains poorly understood. Here we show that the C-terminal region (residues 517–551) of Cdc14p can function as a nuclear localization signal (NLS) in vivo and also binds to Kap121p (also known as Pse1p), an essential nuclear import carrier in yeast, in a Gsp1p-GTP-dependent manner in vitro. Moreover we report a crystal structure, at 2.4 Å resolution, of Kap121p bound to the C-terminal region of Cdc14p. The structure and structure-based mutational analyses suggest that either the last five residues at the extreme C-terminus of Cdc14p (residues 547–551; Gly-Ser-Ile-Lys-Lys) or adjacent residues with similar sequence (residues 540–544; Gly-Gly-Ile-Arg-Lys) can bind to the NLS-binding site of Kap121p, with two residues (Ile in the middle and Lys at the end of the five residues) of Cdc14p making key contributions to the binding specificity. Based on comparison with other structures of Kap121p-ligand complexes, we propose “IK-NLS” as an appropriate term to refer to the Kap121p-specific NLS. - Highlights: • The C-terminus of Cdc14p binds to Kap121p in a Gsp1p-GTP-dependent manner. • The crystal structure of Kap121p-Cdc14p complex is determined. • The structure reveals how

  17. Enhanced Bifunctional Oxygen Catalysis in Strained LaNiO3 Perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Petrie, Jonathan R.; Cooper, Valentino R.; Freeland, John W.; Meyer, Tricia L.; Zhang, Zhiyong; Lutterman, Daniel A.; Lee, Ho Nyung

    2016-03-02

    Strain is known to greatly influence low temperature oxygen electro catalysis on noble metal films, leading to significant enhancements in bifunctional activity essential for fuel cells and Metal-air batteries. However, its catalytic impact on transition-metal oxide thin films, such as perovskites, is not widely understood. Here, we epitaxially strain the conducting perovskite LaNiO3 to systematically determine its influence on both the oxygen reduction and oxygen evolution reaction. Uniquely, we found that compressive strain could significantly enhance both reactions, yielding a bifunctional catalyst that surpasses the performance of noble metals' such as Pt. We attribute the improved bifunctionality to strain induced splitting of the e(g) Orbitals, which can customize orbital asymmetry at the surface. Analogous to strain induced shifts in the d-band center of noble metals relative to the Fermi level, :such splitting can dramatically affect catalytic activity in this perovskite and other potentially more active Oxides.

  18. Nickel sulfide microsphere film on Ni foam as an efficient bifunctional electrocatalyst for overall water splitting.

    Science.gov (United States)

    Zhu, Wenxin; Yue, Xiaoyue; Zhang, Wentao; Yu, Shaoxuan; Zhang, Yuhuan; Wang, Jing; Wang, Jianlong

    2016-01-25

    Developing low-cost, efficient, and bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an appealing yet challenging task. Herein, for the first time, a NiS microsphere film was grown in situ on Ni foam (NiS/Ni foam) via a sulfurization reaction as an efficient bifunctional electrocatalyst for overall water splitting with superior activity and good durability. This NiS/Ni foam electrode delivers 20 mA cm(-2) at an overpotential of 158 mV for the HER and 50 mA cm(-2) at an overpotential of 335 mV for the OER in 1.0 M KOH. This bifunctional electrode also enables a high-efficiency alkaline water electrolyzer with 10 mA cm(-2) at a cell voltage of only 1.64 V, which could be promising in water splitting devices for large-scale hydrogen production. PMID:26661579

  19. Polymer-Supported Reagents: The Role of Bifunctionality in the Design of Ion-Selective Complexants

    Energy Technology Data Exchange (ETDEWEB)

    Alexandratos, S. D.

    2001-06-01

    The importance of multi-functionality in the preparation of ion-selective polymers is evident from the structure of enzymes where specific metal ions are bound through cooperative interactions among different amino acids. In synthetic polymers, ionic selectivity is enhanced when a chemical reaction is superimposed on an ion-exchange process. The concept of reactive ion exchange has been extended through the synthesis of crosslinked polymers whose metal ion selectivity is a function of reduction, coordination or precipitation reactions as determined by various covalently bound ligands. Development of three classes of dual mechanism bifunctional polymers, a new series of bifunctional diphosphonate polymers, and novel bifunctional ion-selective polymers with enhanced ionic accessibility has been accomplished.

  20. Synthesis, characterization and catalytic activity of acid-base bifunctional materials through protection of amino groups

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yanqiu [College of Chemistry, Jilin University, Changchun 130023 (China); College of Chemistry, Mudanjiang Normal University, Mudanjiang 157012 (China); Liu, Heng; Yu, Xiaofang [College of Chemistry, Jilin University, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@mail.jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130023 (China)

    2012-03-15

    Graphical abstract: Acid-base bifunctional mesoporous material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized under low acidic medium through protection of amino groups. Highlights: Black-Right-Pointing-Pointer The acid-base bifunctional material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized through protection of amino groups. Black-Right-Pointing-Pointer The obtained bifunctional material was tested for aldol condensation. Black-Right-Pointing-Pointer The SO{sub 3}H-SBA-15-NH{sub 2} catalyst containing amine and sulfonic acid groups exhibited excellent acid-basic properties. -- Abstract: Acid-base bifunctional mesoporous material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized under low acidic medium through protection of amino groups. X-ray diffraction (XRD), N{sub 2} adsorption-desorption, transmission electron micrographs (TEM), back titration, {sup 13}C magic-angle spinning (MAS) NMR and {sup 29}Si magic-angle spinning (MAS) NMR were employed to characterize the synthesized materials. The obtained bifunctional material was tested for aldol condensation reaction between acetone and 4-nitrobenzaldehyde. Compared with monofunctional catalysts of SO{sub 3}H-SBA-15 and SBA-15-NH{sub 2}, the bifunctional sample of SO{sub 3}H-SBA-15-NH{sub 2} containing amine and sulfonic acid groups exhibited excellent acid-basic properties, which make it possess high activity for the aldol condensation.

  1. Physical properties of bifunctional BST/LSMO nanocomposites

    International Nuclear Information System (INIS)

    We report the fabrication of bifunctional nanocomposites consisting of ferroelectric Ba0.7Sr0.3TiO3 (BST) and ferromagnetic La0.67Sr0.33MnO3 (LSMO) at different concentrations via a high-temperature solid state route. The structural, dielectric, electrical, magnetodielectric (MD), magnetoelectric (ME) and magnetic properties of BST/LSMO nanocomposites were systematically investigated over a wide range of temperatures and frequencies. The X-Ray Diffraction analyses reveal the nanocrystalline nature of the heterostructures, wherein both perovskite phases co-exist. No parasitic phases were observed. The study of the dielectric properties shows that the nanocomposites exhibit relaxor ferroelectric character, with ferroelectric-paraelectric phase transition temperatures around 287–292 K that do not follow the Curie-Weiss law. The electrical measurements indicate that ac conductivities of the nanocomposites follow the Jonscher's universal power law, with activation energies of 0.42–0.63 eV based on Arrhenius-type behavior at high temperatures. The nanocomposites exhibit well-defined ferromagnetic hysteresis loops at room temperature (RT). The MD and ME measurements at RT indicate that BST/LSMO exhibits a nonlinear ME effect at low frequencies, with a threshold near 0.5 T. The magnetocapacitance (MCp) measurements evidence a quadratic dependence on magnetic field, further confirming the multiferroic nature of BST/LSMO. The order of MCp was found to be ∼7% per Tesla. The analysis of the MCp measurements indicates that one of the BST/LSMO compositions studied can be considered as a new multiferroic compound

  2. Physical properties of bifunctional BST/LSMO nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Beltran-Huarac, Juan, E-mail: baristary26@gmail.com; Morell, Gerardo [Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931 (United States); Department of Physics, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00936 (United States); Martinez, Ricardo [Department of Mathematics and Physics, University of Puerto Rico, Cayey Campus, Cayey, Puerto Rico 00737 (United States)

    2014-02-28

    We report the fabrication of bifunctional nanocomposites consisting of ferroelectric Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} (BST) and ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) at different concentrations via a high-temperature solid state route. The structural, dielectric, electrical, magnetodielectric (MD), magnetoelectric (ME) and magnetic properties of BST/LSMO nanocomposites were systematically investigated over a wide range of temperatures and frequencies. The X-Ray Diffraction analyses reveal the nanocrystalline nature of the heterostructures, wherein both perovskite phases co-exist. No parasitic phases were observed. The study of the dielectric properties shows that the nanocomposites exhibit relaxor ferroelectric character, with ferroelectric-paraelectric phase transition temperatures around 287–292 K that do not follow the Curie-Weiss law. The electrical measurements indicate that ac conductivities of the nanocomposites follow the Jonscher's universal power law, with activation energies of 0.42–0.63 eV based on Arrhenius-type behavior at high temperatures. The nanocomposites exhibit well-defined ferromagnetic hysteresis loops at room temperature (RT). The MD and ME measurements at RT indicate that BST/LSMO exhibits a nonlinear ME effect at low frequencies, with a threshold near 0.5 T. The magnetocapacitance (MC{sub p}) measurements evidence a quadratic dependence on magnetic field, further confirming the multiferroic nature of BST/LSMO. The order of MC{sub p} was found to be ∼7% per Tesla. The analysis of the MC{sub p} measurements indicates that one of the BST/LSMO compositions studied can be considered as a new multiferroic compound.

  3. Oxidations of amines with molecular oxygen using bifunctional gold–titania catalysts

    DEFF Research Database (Denmark)

    Klitgaard, Søren Kegnæs; Egeblad, Kresten; Mentzel, Uffe Vie;

    2008-01-01

    Over the past decades it has become clear that supported gold nanoparticles are surprisingly active and selective catalysts for several green oxidation reactions of oxygen-containing hydrocarbons using molecular oxygen as the stoichiometric oxidant. We here report that bifunctional gold–titania c......Over the past decades it has become clear that supported gold nanoparticles are surprisingly active and selective catalysts for several green oxidation reactions of oxygen-containing hydrocarbons using molecular oxygen as the stoichiometric oxidant. We here report that bifunctional gold...

  4. Structural basis for bifunctional peptide recognition at human δ-opioid receptor.

    Science.gov (United States)

    Fenalti, Gustavo; Zatsepin, Nadia A; Betti, Cecilia; Giguere, Patrick; Han, Gye Won; Ishchenko, Andrii; Liu, Wei; Guillemyn, Karel; Zhang, Haitao; James, Daniel; Wang, Dingjie; Weierstall, Uwe; Spence, John C H; Boutet, Sébastien; Messerschmidt, Marc; Williams, Garth J; Gati, Cornelius; Yefanov, Oleksandr M; White, Thomas A; Oberthuer, Dominik; Metz, Markus; Yoon, Chun Hong; Barty, Anton; Chapman, Henry N; Basu, Shibom; Coe, Jesse; Conrad, Chelsie E; Fromme, Raimund; Fromme, Petra; Tourwé, Dirk; Schiller, Peter W; Roth, Bryan L; Ballet, Steven; Katritch, Vsevolod; Stevens, Raymond C; Cherezov, Vadim

    2015-03-01

    Bifunctional μ- and δ-opioid receptor (OR) ligands are potential therapeutic alternatives, with diminished side effects, to alkaloid opiate analgesics. We solved the structure of human δ-OR bound to the bifunctional δ-OR antagonist and μ-OR agonist tetrapeptide H-Dmt-Tic-Phe-Phe-NH2 (DIPP-NH2) by serial femtosecond crystallography, revealing a cis-peptide bond between H-Dmt and Tic. The observed receptor-peptide interactions are critical for understanding of the pharmacological profiles of opioid peptides and for development of improved analgesics. PMID:25686086

  5. A nanostructured bifunctional Pd/C gas-diffusion electrode for metal-air batteries

    OpenAIRE

    McKerracher, R.D.; Alegre, C.; Baglio, V.; Aricò, A.S.; Ponce de León, C.; Mornaghini, F.; Rodlert, M.; Walsh, F. C.

    2015-01-01

    Designing a bifunctional air electrode which catalyses both the oxygen reduction and oxygen evolution reactions is an essential part of progress towards fully rechargeable metal-air batteries, such as the iron-air battery which is environmentally friendly, low cost, and does not suffer risk of thermal runaway like lithium-ion batteries. This paper reports the development of a lightweight carbon-based bifunctional air electrode, catalysed by a small (0.5 mg cm?2) loading of 30 wt.% palladium o...

  6. Direct catalytic transformation of carbohydrates into 5-ethoxymethylfurfural with acid–base bifunctional hybrid nanospheres

    DEFF Research Database (Denmark)

    Li, Hu; Khokarale, Santosh Govind; Kotni, Ramakrishna;

    2014-01-01

    A series of acid–base bifunctional hybrid nanospheres prepared from the self-assembly of basic amino acids and phosphotungstic acid (HPA) with different molar ratios were employed as efficient and recyclable catalysts for synthesis of liquid biofuel 5-ethoxymethylfurfural (EMF) from various...... carbohydrates. A high EMF yield of 76.6%, 58.5%, 42.4%, and 36.5% could be achieved, when fructose, inulin, sorbose, and sucrose were used as starting materials, respectively. Although, the acid–base bifunctional nanocatalysts were inert for synthesis of EMF from glucose based carbohydrates, ethyl...

  7. Janus nanobelts: fabrication, structure and enhanced magnetic-fluorescent bifunctional performance

    Science.gov (United States)

    Ma, Qianli; Yu, Wensheng; Dong, Xiangting; Wang, Jinxian; Liu, Guixia

    2014-02-01

    A new nanostructure of magnetic-fluorescent bifunctional Janus nanobelts with Fe3O4/PMMA as one half and Tb(BA)3phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe3O4/PMMA]//[Tb(BA)3phen/PMMA] magnetic-fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special nanostructure. Compared with Fe3O4/Tb(BA)3phen/PMMA composite nanobelts, the magnetic-fluorescent bifunctional Janus nanobelts provided better performance. The new magnetic-fluorescent bifunctional Janus nanobelts have potential applications in novel nano-bio-label materials, drug target delivery materials and future nanodevices due to their excellent magnetic-fluorescent properties, flexibility and insolubility. Moreover, the construction technique for the Janus nanobelts is of universal significance for the fabrication of other multifunctional Janus nanobelts.A new nanostructure of magnetic-fluorescent bifunctional Janus nanobelts with Fe3O4/PMMA as one half and Tb(BA)3phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe3O4/PMMA]//[Tb(BA)3phen/PMMA] magnetic-fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special

  8. Energy Storage in Bifunctional TiO2 Composite Materials under UV and Visible Light

    Directory of Open Access Journals (Sweden)

    Jialin Li

    2009-11-01

    Full Text Available This paper provides an overview of recent studies on energy storage in bifunctional TiO2 composite materials under UV and visible light. The working mechanism, property improvements and applications of these bifunctional TiO2 composite systems are introduced, respectively. The latest results obtained in our laboratory, especially a new process for photoelectric conversion and energy storage in TiO2/Cu2O bilayer films under visible light, are also presented. Hopefully this review will stimulate more fundamental and applied research on this subject in the future.

  9. Cloning and Functional Analysis of the Bifunctional Agglutinin/Trypsin Inhibitor from Helianthus tuberosus L.

    Institute of Scientific and Technical Information of China (English)

    Tuanjie Chang; Hongli Zhai; Songbiao Chen; Guisheng Song; Honglin Xu; Xiaoli Wei; Zhen Zhu

    2006-01-01

    In order to find new insect resistance genes, four homologous cDNAs, hta-a, hta-b, hta-c and hta-d with lengths of 775, 718, 784 and 752 bp, respectively (GenBank accession numbers AF477031-AF477034), were isolated from a tuber cDNA expression library of Helianthus tuberosus L. Sequence analysis revealed that all four cDNAs contain an open reading frame of 444 bp, coding a polypeptide of 147 amino acid residues, and that the sequences of the cDNAs are very similar to those of the mannose-binding agglutinin genes of the jacalin-related family. In hemagglutination reactions and hapten inhibition assays, affinity-purified HTA (Helianthus tuberosus agglutinin) from induced Escherichia coli BL21(DE3) expressing GST-HTA shows hemagglutination ability and a higher carbohydrate-binding ability for mannose than other tested sugars.Trypsin inhibitory activity was detected in the crude extracts of induced E. coli BL21(DE3)expressing HTA,and was further verified by trypsin inhibitory activity staining on native polyacrylamide gel. The mechanism of interaction between HTA and trypsin was studied by molecular modeling. We found that plenty of hydrogen bonds and electrostatic interactions can be formed between the supposed binding sites of HTA-b and the active site of trypsin, and that a stable HTA/trypsin complex can be formed. The results above imply that HTA might be a bifunctional protein with carbohydrate-binding activity and trypsin inhibitory activity. Moreover,Northern blotting analysis demonstrated that hta is predominantly expressed in tubers of H. tuberosus, very weakly expressed in stems, but not expressed at all in other tissues. Southern blotting analysis indicated that hta is encoded by a multi-gene family. The insect resistance traits have been described in another paper.

  10. Improvement of L-arginine production by overexpression of a bifunctional ornithine acetyltransferase in Corynebacterium crenatum.

    Science.gov (United States)

    Dou, Wenfang; Xu, Meijuan; Cai, Dongmei; Zhang, Xiaomei; Rao, Zhiming; Xu, Zhenghong

    2011-10-01

    Ornithine acetyltransferase (EC 2.3.1.35; OATase) gene (argJ) from the L-arginine-producing mutant Corynebacterium crenatum SYPA5-5 was cloned, sequenced, and expressed in Escherichia coli BL21 (DE3). Analysis of the argJ sequence revealed that the argJ coded a polypeptide of 388 amino acids with a calculated molecular weight of 39.7 kDa. In this study, the function of the OATase (argJ) of C. crenatum SYPA5-5 has been identified as a conserved ATML sequence for the autolysis of the protein to α- and β-subunits. When the argJ regions corresponding to the α- and β-subunits were cloned and expressed separately in E. coli BL21, OATase activities were abolished. At the same time, a functional study revealed that OATase from C. crenatum SYPA5-5 was a bifunctional enzyme with the functions of acetylglutamate synthase (EC 2.3.1.1, NAGS) and acetylornithine deacetylase (EC 3.5.1.16, AOase) activities. In order to investigate the effects of the overexpression of the argJ gene on L: -arginine production, the argJ gene was inserted into pJCtac to yield the recombinant shuttle plasmid pJCtac-argJ and then transformed into C. crenatum SYPA5-5. The results showed that the engineered strains could not only express more OATase (90.9%) but also increase the production of L: -arginine significantly (16.8%). PMID:21785983

  11. Characterization and kinetic mechanism of mono- and bifunctional ornithine acetyltransferases from thermophilic microorganisms.

    Science.gov (United States)

    Marc, F; Weigel, P; Legrain, C; Almeras, Y; Santrot, M; Glansdorff, N; Sakanyan, V

    2000-08-01

    The argJ gene coding for N2-acetyl-L-ornithine: L-glutamate N-acetyltransferase, the key enzyme involved in the acetyl cycle of L-arginine biosynthesis, has been cloned from thermophilic procaryotes: the archaeon Methanoccocus jannaschii, and the bacteria Thermotoga neapolitana and Bacillus stearothermophilus. Archaeal argJ only complements an Escherichia coli argE mutant (deficient in acetylornithinase, which catalyzes the fifth step in the linear biosynthetic pathway), whereas bacterial genes additionally complement an argA mutant (deficient in N-acetylglutamate synthetase, the first enzyme of the pathway). In keeping with these in vivo data the purified His-tagged ArgJ enzyme of M. jannaschii only catalyzes N2-acetylornithine conversion to ornithine, whereas T. neapolitana and B. stearothermophilus ArgJ also catalyze the conversion of glutamate to N-acetylglutamate using acetylCoA as the acetyl donor. M. jannaschii ArgJ is therefore a monofunctional enzyme, whereas T. neapolitana and B. stearothermophilus encoded ArgJ are bifunctional. Kinetic data demonstrate that in all three thermophilic organisms ArgJ-mediated catalysis follows ping-pong bi-bi kinetic mechanism. Acetylated ArgJ intermediates were detected in semireactions using [14C]acetylCoA or [14C]N2-acetyl-L-glutamate as acetyl donors. In this catalysis L-ornithine acts as an inhibitor; this amino acid therefore appears to be a key regulatory molecule in the acetyl cycle of L-arginine synthesis. Thermophilic ArgJ are synthesized as protein precursors undergoing internal cleavage to generate alpha and beta subunits which appear to assemble to alpha2beta2 heterotetramers in E. coli. The cleavage occurs between alanine and threonine residues within the highly conserved PXM-ATML motif detected in all available ArgJ sequences. PMID:10931207

  12. Bifunctional oligodeoxynucleotide/antagomiR constructs: evaluation of a new tool for microRNA silencing.

    Science.gov (United States)

    Ziegler, Saskia; Eberle, Mariel Esther; Wölfle, Sabine J; Heeg, Klaus; Bekeredjian-Ding, Isabelle

    2013-12-01

    MicroRNAs (miRNAs) are fine-tuners in cellular processes, including those of the immune response. To study their functions and effects in immune cells, it is necessary to achieve specific silencing of individual miRNAs. To date, introduction of antisense microRNAs (antagomiRs) into primary cells is based on electroporation, lipofection, and viral vectors. However, these techniques often compromise viability, proliferative capacity, and differentiation. Furthermore, efficiency varies depending on the cell type and some are not suitable for in vivo approaches. To overcome these limitations we exploited the property of phosphorothioate (PTO)-modified DNA oligodeoxynucleotides (ODN) to enter cells with high efficacy: we developed and evaluated ODN/antagomiR constructs that consist of a PTO-ODN carrier covalently linked to a fully methylated antagomiR RNA sequence. Using these constructs, we achieved transfection efficiency of approximately 99% in leukocytes-in particular, in B lymphocytes that are hard to transfect with other methods. Our data demonstrate that miRNA silencing by the antagomiR portion of the constructs was specific and efficient, which could be further confirmed by an increase in target protein under silencing conditions. The constructs were successfully tested in human B cells, plasmacytoid dendritic cells, monocytes, and monocyte-derived dendritic cells, thus demonstrating their versatility. Moreover, introduction of stimulatory CpG sequences into the ODN portion conveys immune stimulatory quality when intended. Thus, bifunctional ODN/antagomiR constructs represent a highly efficient, versatile, and easy-to-handle tool to manipulate cellular miRNA expression levels and to allow the subsequent investigation of specific miRNA functions. PMID:24236889

  13. Two-dimensional Electrophoresis Analysis of Proteins in Response to Cold Stress in Extremely Cold-resistant Winter Wheat Dongnongdongmai 1 Tillering Nodes

    Institute of Scientific and Technical Information of China (English)

    Cang Jing; Yu Jing; Liu Li-jie; Yang Yang; Cui Hong; Hao Zai-bin; Li Zhuo-fu

    2012-01-01

    The overwintering survival ratio of the cultivar Dongnongdongmai 1 with strong cold-resistance in paramos of Heilongjiang Province in China are over 85%. The tillering nodes are the most important organs for overwintering survival of winter wheat, because there are more substances associated with cold resistance in tillering nodes than those in leaves and roots. Proteins in the tillering nodes of the cold-resistant cultivar Dongnongdongmai 1 grown under field conditions with or without any lowtemperature stress were analyzed by 2-dimensional electrophoresis and identified by mass spectrometry. In the range of pH 4-7, the expression of 37 proteins showed obvious difference (±more than two fold) in the proteomic maps of cold-stressed and non-stressed tillering nodes, including a new protein spot. All proteins exhibiting the difference in expression were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, followed by a database search for protein identification and function prediction. Five groups of proteins were confirmed, namely stress-related proteins (22%), metabolism-associated proteins (35%), and signaling molecules (24%), cell wall-binding proteins (5%), unclear proteins (14%). This indicated that tillering node cells supported the energy requirements of plant growth and stress resistance by signal transduction adapting to metabolism and structure.

  14. Yeast Interacting Proteins Database: YER081W, YDL168W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available y (0 or 1,YPD) 0 Co-induced by (YPD) - Co-repressed by (YPD) - Not affected by(YPD) - Interologs - Expression si... Rows with this bait as prey Rows with this bait as prey (1) Prey ORF YDL168W Prey gene name SFA1 Prey description Bifunction...al enzyme containing both alcohol dehydrogenase and glutathione-dependent formaldehyde de...ative path with 2 intervening proteins (YPD) 0 IST hit 4 IST hit in the opposite bait/prey orientation - ... ...YER081W SER3 3-phosphoglycerate dehydrogenase, catalyzes the first step in serine and glycine biosynthesi

  15. Comparison of bifunctional chelates for {sup 64}Cu antibody imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Cara L.; Crisp, Sarah; Bensimon, Corinne [MDS Nordion, Vancouver, BC (Canada); Yapp, Donald T.T.; Ng, Sylvia S.W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); University of British Columba, The Faculty of Pharmaceutical Sciences, Vancouver, BC (Canada); Sutherland, Brent W. [British Columbia Cancer Agency Research Centre, Vancouver, BC (Canada); Gleave, Martin [Prostate Centre at Vancouver General Hospital, Vancouver, BC (Canada); Jurek, Paul; Kiefer, Garry E. [Macrocyclics Inc., Dallas, TX (United States)

    2010-11-15

    Improved bifunctional chelates (BFCs) are needed to facilitate efficient {sup 64}Cu radiolabeling of monoclonal antibodies (mAbs) under mild conditions and to yield stable, target-specific agents. The utility of two novel BFCs, 1-Oxa-4,7,10-triazacyclododecane-5-S-(4-isothiocyanatobenzyl)-4,7,10-triacetic acid (p-SCN-Bn-Oxo-DO3A) and 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-4-S-(4-isothiocyanatobenzyl)-3,6,9-triacetic acid (p-SCN-Bn-PCTA), for mAb imaging with {sup 64}Cu were compared to the commonly used S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (p-SCN-Bn-DOTA). The BFCs were conjugated to trastuzumab, which targets the HER2/neu receptor. {sup 64}Cu radiolabeling of the conjugates was optimized. Receptor binding was analyzed using flow cytometry and radioassays. Finally, PET imaging and biodistribution studies were done in mice bearing either HER2/neu-positive or HER2/neu-negative tumors. {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab were prepared at room temperature in >95% radiochemical yield (RCY) in <30 min, compared to only 88% RCY after 2 h for the preparation of {sup 64}Cu-DOTA-trastuzumab under the same conditions. Cell studies confirmed that the immunoreactivity of the mAb was retained for each of the bioconjugates. In vivo studies showed that {sup 64}Cu-Oxo-DO3A- and PCTA-trastuzumab had higher uptake than the {sup 64}Cu-DOTA-trastuzumab at 24 h in HER2/neu-positive tumors, resulting in higher tumor to background ratios and better tumor images. By 40 h all three of the {sup 64}Cu-BFC-trastuzumab conjugates allowed for clear visualization of the HER2/neu-positive tumors but not the negative control tumor. The antibody conjugates of PCTA and Oxo-DO3A were shown to have superior {sup 64}Cu radiolabeling efficiency and stability compared to the analogous DOTA conjugate. In addition, {sup 64}Cu-PCTA and Oxo-DO3A antibody conjugates may facilitate earlier imaging with greater target to background ratios than

  16. Bifunctional phage-based pretargeted imaging of human prostate carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Newton-Northup, Jessica R. [Department of Biochemistry, University of Missouri, Columbia, MO 65211 (United States)], E-mail: newtonj@missouri.edu; Figueroa, Said D. [Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); Quinn, Thomas P.; Deutscher, Susan L. [Department of Biochemistry, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S. Truman Veterans Memorial Hospital, Columbia, MO 65201 (United States)

    2009-10-15

    Introduction: Two-step and three-step pretargeting systems utilizing biotinylated prostate tumor-homing bacteriophage (phage) and {sup 111}In-radiolabeled streptavidin or biotin were developed for use in cancer radioimaging. The in vivo selected prostate carcinoma-specific phage (G1) displaying up to five copies of the peptide IAGLATPGWSHWLAL was the focus of the present study. Methods: The ability of G1 phage to extravasate and target prostate tumor cells was investigated using immunohistochemistry. G1 phages were biotinylated, streptavidin was conjugated to diethylenetriaminepentaacetic acid (DTPA) and biotin was conjugated to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). Biodistribution studies and single-photon emission computed tomography (SPECT)/CT imaging of xenografted PC-3 tumors via two-step pretargeted {sup 111}In-labeled streptavidin and three-step pretargeted {sup 111}In-labeled biotin were performed in SCID mice to determine the optimal pretargeting method. Results: The ability of G1 phage to extravasate the vasculature and bind directly to human PC-3 prostate carcinoma tumor cells in vivo was demonstrated via immunocytochemical analysis. Comparative biodistribution studies of the two-step and three-step pretargeting strategies indicated increased PC-3 human prostate carcinoma tumor uptake in SCID mice of 4.34{+-}0.26 %ID g{sup -1} at 0.5 h postinjection of {sup 111}In-radiolabeled biotin (utilized in a three-step protocol) compared to 0.67{+-}0.06 %ID g{sup -1} at 24 h postinjection of {sup 111}In radiolabeled streptavidin (employed in a two-step protocol). In vivo SPECT/CT imaging of xenografted PC-3 tumors in SCID mice with the three-step pretargeting method was superior to that of the two-step pretargeting method, and, importantly, blocking studies demonstrated specificity of tumor uptake of {sup 111}In-labeled biotin in the three-step pretargeting scheme. Conclusion: This study demonstrates the use of multivalent bifunctional

  17. Direct catalytic transformation of carbohydrates into 5-ethoxymethylfurfural with acid–base bifunctional hybrid nanospheres

    International Nuclear Information System (INIS)

    Graphical abstract: Catalytic conversion of carbohydrates into HMF and EMF in ethanol/DMSO with acid–base bifunctional hybrid nanospheres prepared from self-assembly of corresponding basic amino acids and HPA. - Highlights: • Acid–base bifunctional nanospheres were efficient for production of EMF from sugars. • Synthesis of EMF in a high yield of 76.6% was realized from fructose. • Fructose based biopolymers could also be converted into EMF with good yields. • Ethyl glucopyranoside was produced in good yields from glucose in ethanol. - Abstract: A series of acid–base bifunctional hybrid nanospheres prepared from the self-assembly of basic amino acids and phosphotungstic acid (HPA) with different molar ratios were employed as efficient and recyclable catalysts for synthesis of liquid biofuel 5-ethoxymethylfurfural (EMF) from various carbohydrates. A high EMF yield of 76.6%, 58.5%, 42.4%, and 36.5% could be achieved, when fructose, inulin, sorbose, and sucrose were used as starting materials, respectively. Although, the acid–base bifunctional nanocatalysts were inert for synthesis of EMF from glucose based carbohydrates, ethyl glucopyranoside in good yields could be obtained from glucose in ethanol. Moreover, the nanocatalyst functionalized with acid and basic sites was able to be reused several times with no significant loss in catalytic activity

  18. Synthesis, characterization and use of ATRP bifunctional initiator with trichloromethyl end-groups

    Czech Academy of Sciences Publication Activity Database

    Toman, Luděk; Janata, Miroslav; Spěváček, Jiří; Masař, Bohumil; Vlček, Petr; Látalová, Petra

    2002-01-01

    Roč. 43, č. 2 (2002), s. 18-19. ISSN 0032-3934 R&D Projects: GA ČR GA203/01/0513 Institutional research plan: CEZ:AV0Z4050913 Keywords : bifunctional initiator * ATRP polymerization * trichloromethyl end-groups Subject RIV: CD - Macromolecular Chemistry

  19. Structure and potential applications of amido lanthanide complexes chelated by bifunctional b-diketiminate ligand

    Czech Academy of Sciences Publication Activity Database

    Olejník, R.; Padělková, Z.; Fridrichová, A.; Horáček, Michal; Merna, J.; Růžička, A.

    2014-01-01

    Roč. 759, JUN 2014 (2014), s. 1-10. ISSN 0022-328X R&D Projects: GA ČR GAP106/10/0924 Institutional support: RVO:61388955 Keywords : Bifunctional b-diketiminates * lanthanides * hydroamination Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.173, year: 2014

  20. Asymmetric α-amination of β-keto esters using a guanidine–bisurea bifunctional organocatalyst

    Science.gov (United States)

    Yamamoto, Yoshiharu

    2016-01-01

    Summary An asymmetric α-amination of β-keto esters with azodicarboxylate in the presence of a guanidine–bisurea bifunctional organocatalyst was investigated. The α-amination products were obtained in up to 99% yield with up to 94% ee. PMID:26977179

  1. High surface area carbon for bifunctional air electrodes applied in zinc-air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Arai, H. [on leave from NTT Laboratories (Japan); Mueller, S.; Haas, O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Bifunctional air electrodes with high surface area carbon substrates showed low reduction overpotential, thus are promising for enhancing the energy efficiency and power capability of zinc-air batteries. The improved performance is attributed to lower overpotential due to diffusion of the reaction intermediate, namely the peroxide ion. (author) 1 fig., 2 refs.

  2. Bifunctional catalysts for the direct production of liquid fuels from syngas

    NARCIS (Netherlands)

    Sartipi, S.

    2014-01-01

    Design and development of catalyst formulations that maximize the direct production of liquid fuels by combining Fischer-Tropsch synthesis (FTS), hydrocarbon cracking, and isomerization into one single catalyst particle (bifunctional FTS catalyst) have been investigated in this thesis. To achieve th

  3. Study of Protein Fold Recognition Using Optimization Method Extreme Learning Machine for Classification%极限学习机优化方法在蛋白质折叠类型识别中的应用

    Institute of Scientific and Technical Information of China (English)

    张志锋; 范乃梅

    2013-01-01

    传统的机器学习方法在处理蛋白质折叠类型识别问题时需要花费大量的时间来调节最佳的参数.利用一种新的极限学习机(Extreme Learning Machine,ELM)分类优化方法(Extreme Learning Machine for Classification,ELMC)对蛋白质折叠进行识别,仅需调节很少的参数值就可达到很好的测试精度.与支持向量机(Support Vector Machine,SVM)和推荐相关向量机(Relevance Vector Machine,RVM)相比,ELMC能获得更好的泛化性能,而且在寻找最优解的训练时间比较上,ELMC比SVM平均要快35倍,比RVM要快12倍.%With traditional machine learning methods, one may spends a lot of time adjusting the optimal parameters in tackling the problem of protein fold recognition. A new optimization method of extreme learning machine for classification ( ELMC ) is used to recognize the protein fold, one can only adjusts few parameters to achieve good enough testing accuracy. Compared to support vector machine (SVM)and relevance vector machine (RVM) , better generalization performance can be obtained by extreme earning machine for classification. In the comparison of training time in finding the optimal solution, ELMC is 35 times faster than SVM averagely and is 12 times faster than RVM averagely.

  4. Interaction between wheat alpha-amylase/trypsin bi-functional inhibitor and mammalian digestive enzymes: Kinetic, equilibrium and structural characterization of binding.

    Science.gov (United States)

    Cuccioloni, Massimiliano; Mozzicafreddo, Matteo; Ali, Ishtiaq; Bonfili, Laura; Cecarini, Valentina; Eleuteri, Anna Maria; Angeletti, Mauro

    2016-12-15

    Alpha-amylase/trypsin bi-functional inhibitors (ATIs) are non-gluten protein components of wheat and other cereals that can hypersensitise the human gastrointestinal tract, eventually causing enteropathies in predisposed individuals. These inhibitory proteins can act both directly by targeting specific pro-inflammatory receptors, and indirectly by impairing the activity of digestive enzymes, the latter event causing the accumulation of undigested peptides with potential immunogenic properties. Herein, according to a concerted approach based on in vitro and in silico methods we characterized kinetics, equilibrium parameters and modes of binding of the complexes formed between wheat ATI and two representative mammalian digestive enzymes, namely trypsin and alpha-amylase. Interestingly, we demonstrated ATI to target both enzymes with independent binding sites and with moderately high affinity. PMID:27451220

  5. Imaging cancer using PET - the effect of the bifunctional chelator on the biodistribution of a 64Cu-labeled antibody

    International Nuclear Information System (INIS)

    Introduction: Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the 64Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with 64Cu using these chelators in tumor-bearing mice. Methods: The chelators [S-2-(aminobenzyl)1,4,7-triazacyclononane-1,4,7-triacetic acid (p-NH2-Bn-NOTA): 6-[p-(bromoacetamido)benzyl]-1, 4, 8, 11-tetraazacyclotetradecane-N, N', N'', N'''-tetraacetic acid (BAT-6): S-2-(4-aminobenzyl)-1,4,7,10-tetraazacyclododocane tetraacetic acid (p-NH2-Bn-DOTA): 1,4,7,10-tetraazacyclododocane-N, N', N', N''-tetraacetic acid (DOTA): and 1-N-(4-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1, 8-diamine (SarAr)] were conjugated to the anti-GD2 antibody ch14.18, and the modified antibody was labeled with 64Cu and injected into mice bearing subcutaneous human melanoma tumors (M21) (n = 3-5 for each study). Biodistribution data were obtained from positron emission tomography images acquired at 1, 24 and 48 hours post-injection, and at 48 hours post-injection a full ex vivo biodistribution study was carried out. Results: The biodistribution, including tumor targeting, was similar for all the radioimmunoconjugates. At 48 h post-injection, the only statistically significant differences in radionuclide uptake (p 64Cu]ch14.18-p-NH2-Bn-NOTA was 4.74 ± 0.77 per cent of the injected dose per gram of tissue (%ID/g), and for [64Cu]ch14.18-SarAr was 8.06 ± 0.77 %ID/g. Differences in tumor targeting correlated with variations in tumor size rather than which BFC was used. Conclusions: The results of this study indicate that differences in the thermodynamic stability of these chelator-Cu(II) complexes were not associated with significant differences in uptake of the tracer by the tumor

  6. Effect of bifunctional RDP-BDNF fusion protein on ability of learning and memory of cognitive dysfunction mice induced by scopolamine%双功能融合蛋白RDP-BDNF对东莨菪碱所致认知功能障碍小鼠学习记忆的影响

    Institute of Scientific and Technical Information of China (English)

    张苗苗; 张恩齐; 高飞燕; 吴静; 项松涛; 付爱玲

    2014-01-01

    Aim Through identification of the difunc-tionality of neuroprotection and passage of blood-brain barrier ( BBB) for RDP-BDNF fusion protein to offer a new strategy to treat brain diseases. Methods BDNF was conjugated to a novel cell penetrating peptide known as RDP which was derived from rabies virus gly-coprotein ( RVG) . The fusion protein RDP-BDNF was expressed in E. coli BL21 ( DE3 ) . After the intrave-nous injection of RDP-BDNF, the time effect curve of RDP-BDNF in the brains and serum was examined. Additionally , Morris water maze test was used to evalu-ate the effect of RDP-BDNF on scopolamine-induced amnesic mice, and the mechanism was also studied. Results RDP-BDNF could cross the BBB and exhibi-ted neuroprotective effects on the treatment of cognitive deficit induced by scopolamine in dementia model mice. Conclusions Delivery of protein therapeutics using RDP might offer a new and exciting strategy to treat brain diseases.%目的:研究融合蛋白 RDP-BDNF穿越血脑屏障和神经保护活性的双重功能,为脑部疾病的治疗提供一种新方法。方法我们将新型穿膜肽狂犬病毒糖蛋白衍生肽( RDP)基因与BDNF基因融合并在大肠杆菌中表达,融合蛋白经尾静脉注射入小鼠体内,用 ELISA 法检测 RDP-BDNF在脑和血清中的时效曲线;另外通过Morris水迷宫法研究融合蛋白对东莨菪碱所致的认知功能障碍小鼠学习记忆的影响,并探究其作用的机制。结果 RDP-BDNF可以穿过血脑屏障,且能提高东莨菪碱所致认知功能障碍小鼠的学习记忆能力。结论通过载体RDP介导实现蛋白质的入脑转运可能为脑部疾病的治疗提供一种新方法。

  7. Biochemical characterization of a bifunctional acetaldehyde-alcohol dehydrogenase purified from a facultative anaerobic bacterium Citrobacter sp. S-77.

    Science.gov (United States)

    Tsuji, Kohsei; Yoon, Ki-Seok; Ogo, Seiji

    2016-03-01

    Acetaldehyde-alcohol dehydrogenase (ADHE) is a bifunctional enzyme consisting of two domains of an N-terminal acetaldehyde dehydrogenase (ALDH) and a C-terminal alcohol dehydrogenase (ADH). The enzyme is known to be important in the cellular alcohol metabolism. However, the role of coenzyme A-acylating ADHE responsible for ethanol production from acetyl-CoA remains uncertain. Here, we present the purification and biochemical characterization of an ADHE from Citrobacter sp. S-77 (ADHES77). Interestingly, the ADHES77 was unable to be solubilized from membrane with detergents either 1% Triton X-100 or 1% Sulfobetaine 3-12. However, the enzyme was easily dissociated from membrane by high-salt buffers containing either 1.0 M NaCl or (NH4)2SO4 without detergents. The molecular weight of a native protein was estimated as approximately 400 kDa, consisting of four identical subunits of 96.3 kDa. Based on the specific activity and kinetic analysis, the ADHES77 tended to have catalytic reaction towards acetaldehyde elimination rather than acetaldehyde formation. Our experimental observation suggests that the ADHES77 may play a pivotal role in modulating intracellular acetaldehyde concentration. PMID:26216639

  8. Bifunctional Nb/Ti-MCM-41 catalyst in oxidative acidic reaction of cyclohexene to diol

    International Nuclear Information System (INIS)

    Bifunctional oxidative and acidic catalyst was prepared by incorporating titanium ion (Ti4+) and niobic acid in meso porous molecular sieves MCM-41 structure. The catalyst is active both in oxidation, and acid-catalyzed reaction of olefin to diol. Nb/ Ti-MCM-41 catalyst was prepared by first synthesizing Ti-MCM-41 by hydrothermal method, followed by subsequent impregnation of niobic acid (Nb) into Ti-MCM-41 at various % wt Nb loading. The framework structure of Ti-MCM-41 collapsed after incorporation of Nb but the tetrahedral form of Ti4+ still maintained with octahedral Nb species. Both Bronsted and Lewis acid sites are present in all Nb/ Ti-MCM-41 samples. The formation of cyclohexanediol in the epoxidation of cyclohexene proved the bifunctional oxidative and acidic catalyst through the formation of cyclohexane oxide. The yield increased with the increase amount of the Bronsted acid sites provided by niobium species. (author)

  9. Tethering metal ions to photocatalyst particulate surfaces by bifunctional molecular linkers for efficient hydrogen evolution

    KAUST Repository

    Yu, Weili

    2014-08-19

    A simple and versatile method for the preparation of photocatalyst particulates modified with effective cocatalysts is presented; the method involves the sequential soaking of photocatalyst particulates in solutions containing bifunctional organic linkers and metal ions. The modification of the particulate surfaces is a universal and reproducible method because the molecular linkers utilize strong covalent bonds, which in turn result in modified monolayer with a small but controlled quantity of metals. The photocatalysis results indicated that the CdS with likely photochemically reduced Pd and Ni, which were initially immobilized via ethanedithiol (EDT) as a linker, were highly efficient for photocatalytic hydrogen evolution from Na2S-Na2SO3-containing aqueous solutions. The method developed in this study opens a new synthesis route for the preparation of effective photocatalysts with various combinations of bifunctional linkers, metals, and photocatalyst particulate materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. First-Principles Study of Structure Property Relationships of Monolayer (Hydroxy)Oxide-Metal Bifunctional Electrocatalysts

    DEFF Research Database (Denmark)

    Zeng, Zhenhua; Kubal, Joseph; Greeley, Jeffrey Philip

    2015-01-01

    information that is inaccessible by purely experimental means, and these structures, in turn, strongly suggest that a bifunctional reaction mechanism for alkaline HER will be operative at the interface between the films, the metal substrates, and the surrounding aqueous medium. This bifunctionality produces...... under alkaline electrochemical conditions. We demonstrate that the structure and oxidation state of the films can be systematically tuned by changing the applied electrode potential and/or the nature of substrates. Structural features determined from the theoretical calculations provide a wealth of...... important changes in the calculated barriers of key elementary reaction steps, including water activation and dissociation, as compared to traditional monofunctional Pt surfaces. The successful identification of the structures of thin metal films and three-phase boundary catalysts is not only an important...

  11. Sorption of Pu(IV) from nitric acid by bifunctional anion-exchange resins

    International Nuclear Information System (INIS)

    Anion exchange is attractive for separating plutonium because the Pu(IV) nitrate complex is very strongly sorbed and few other metal ions form competing anionic nitrate complexes. The major disadvantage of this process has been the unusually slow rate at which the Pu(IV) nitrate complex is sorbed by the resin. The paper summarizes the concept of bifunctional anion-exchange resins, proposed mechanism for Pu(IV) sorption, synthesis of the alkylating agent, calculation of Kd values from Pu(IV) sorption results, and conclusions from the study of Pu(IV) sorption from 7M nitric acid by macroporous anion-exchange resins including level of crosslinking, level of alkylation, length of spacer, and bifunctional vs. monofunctional anion-exchange resins

  12. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products. PMID:25721170

  13. Identification and characterization of a thermostable bifunctional enzyme with phosphomannose isomerase and sugar-1-phosphate nucleotidylyltransferase activities from a hyperthermophilic archaeon, Pyrococcus horikoshii OT3.

    Science.gov (United States)

    Akutsu, Jun-ichi; Zhang, Zilian; Morita, Rihito; Kawarabayasi, Yutaka

    2015-11-01

    Mannosylglycerate is known as a compatible solute, and plays important roles for salinity adaptation and high temperature stability of microorganisms. In the gene cluster for the mannosylglycerate biosynthetic pathway predicted from the genomic data of Pyrococcus horikoshii OT3, the PH0925 protein was found as a putative bifunctional enzyme with phosphomannose isomerase (PMI) and mannose-1-phosphate guanylyltransferase (Man-1-P GTase) activities, which can synthesize GDP-mannose when accompanied by a phosphomannomutase/phosphoglucomutase (PMM/PGM) enzyme (PH0923). The recombinant PH0925 protein, expressed in E. coli, exhibited both expected PMI and Man-1-P GTase activities, as well as absolute thermostability; 95 °C was the optimum reaction temperature. According to the guanylyltransferase activity (GTase) of the PH0925 protein, it was found that the protein can catalyze glucose-1-phosphate (Glc-1-P) and glucosamine-1-phosphate (GlcN-1-P) in addition to Man-1-P. The analyses of C-terminus-truncated forms of the PH0925 protein indicated that sugar-1-phosphate nucleotidylyltransferase (Sugar-1-P NTase) activity was located in the region from the N-terminus to the 345th residue, and that the C-terminal 114 residue region of the PH0925 protein inhibited the Man-1-P GTase activity. Conversely, the PMI activity was abolished by deletion of the C-terminal 14 residues. This is the first report of a thermostable enzyme with both PMI and multiple Sugar-1-P NTase activities. PMID:26290359

  14. Bifunctional alkylating agent-mediated MGMT-DNA cross-linking and its proteolytic cleavage in 16HBE cells.

    Science.gov (United States)

    Cheng, Jin; Ye, Feng; Dan, Guorong; Zhao, Yuanpeng; Wang, Bin; Zhao, Jiqing; Sai, Yan; Zou, Zhongmin

    2016-08-15

    Nitrogen mustard (NM), a bifunctional alkylating agent (BAA), contains two alkyl arms and can act as a cross-linking bridge between DNA and protein to form a DNA-protein cross-link (DPC). O(6)-methylguanine-DNA methyltransferase (MGMT), a DNA repair enzyme for alkyl adducts removal, is found to enhance cell sensitivity to BAAs and to promote damage, possibly due to its stable covalent cross-linking with DNA mediated by BAAs. To investigate MGMT-DNA cross-link (mDPC) formation and its possible dual roles in NM exposure, human bronchial epithelial cell line 16HBE was subjected to different concentrations of HN2, a kind of NM, and we found mDPC was induced by HN2 in a concentration-dependent manner, but the mRNA and total protein of MGMT were suppressed. As early as 1h after HN2 treatment, high mDPC was achieved and the level maintained for up to 24h. Quick total DPC (tDPC) and γ-H2AX accumulation were observed. To evaluate the effect of newly predicted protease DVC1 on DPC cleavage, we applied siRNA of MGMT and DVC1, MG132 (proteasome inhibitor), and NMS-873 (p97 inhibitor) and found that proteolysis plays a role. DVC1 was proven to be more important in the cleavage of mDPC than tDPC in a p97-dependent manner. HN2 exposure induced DVC1 upregulation, which was at least partially contributed to MGMT cleavage by proteolysis because HN2-induced mDPC level and DNA damage was closely related with DVC1 expression. Homologous recombination (HR) was also activated. Our findings demonstrated that MGMT might turn into a DNA damage promoter by forming DPC when exposed to HN2. Proteolysis, especially DVC1, plays a crucial role in mDPC repair. PMID:27342729

  15. Radiation Induced Crosslinking of Polyethylene in the Presence of Bifunctional Vinyl Monomers

    DEFF Research Database (Denmark)

    Joshi, M. S.; Singer, Klaus Albert Julius; Silverman, J.

    Several reports have been published showing that the radiation induced grafting of bifunctional vinyl monomers to low density polyethylene results in a product with an unusually high density of crosslinks. The same grafting reactions are shown to reduce the incipient gel dose by more than a factor...... of fifty. This paper is concerned with the apparent crosslinking produced by the radiation grafting of two monomers to polyethylene: acrylic acid and acrylonitrile....

  16. Bifunctional silica nanoparticles for the exploration of biofilms of Pseudomonas aeruginosa

    OpenAIRE

    Mauline, Léïla; Gressier, Marie; Roques, Christine; Hammer, Peter,; Ribeiro, Sidney J. L.; Caiut, José Maurício A.; Menu, Marie-Joëlle

    2013-01-01

    Luminescent silica nanoparticles are frequently employed for biotechnology applications mainly because of their easy functionalization, photo-stability, and biocompatibility. Bifunctional silica nanoparticles (BSNPs) are described here as new efficient tools for investigating complex biological systems such as biofilms. Photoluminescence is brought about by the incorporation of a silylated ruthenium (II) complex. The surface properties of the silica particles were designed by reaction with am...

  17. L-Proline Derived Bifunctional Organocatalysts: Enantioselective Michael Addition of Dithiomalonates to trans-β-Nitroolefins.

    Science.gov (United States)

    Jin, Hui; Kim, Seung Tae; Hwang, Geum-Sook; Ryu, Do Hyun

    2016-04-15

    A series of novel L-proline derived tertiary amine bifunctional organocatalysts 9 are reported, which were applied to the asymmetric Michael addition of dithiomalonates 2 to trans-β-nitroolefins 1. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (R)-phenibut in high yield. PMID:26989804

  18. 3D Ordered Mesoporous Bifunctional Oxygen Catalyst for Electrically Rechargeable Zinc-Air Batteries.

    Science.gov (United States)

    Park, Moon Gyu; Lee, Dong Un; Seo, Min Ho; Cano, Zachary Paul; Chen, Zhongwei

    2016-05-01

    To enhance energy efficiency and durability, a highly active and durable 3D ordered mesoporous cobalt oxide framework has been developed for rechargeable zinc-air batteries. The bifunctional air electrode consisting of 3DOM Co3 O4 having high active surface area and robust structure, results in superior charge and discharge battery voltages, and durable performance for electrically rechargeable zinc-air batteries. PMID:27043451

  19. Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

    2011-06-15

    Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

  20. 67Ga(NODASA): a new potential bifunctional radioligand for coupling to peptides

    International Nuclear Information System (INIS)

    A new bifunctional chelator NODASA (1,4,7-triazacyclononane-1-succinic acid-4,7-diacetic acid) has been synthesised and its Ga(III) complex was crystallographically characterized by X-ray diffraction. The complex showed to be stable in serum and in acidic conditions and its stability constant was determined using a competition method with an auxiliary ligand. The conjugation of Ga(NODASA) to a model aminoacidamide proved the feasibility of a prelabelling approach. (author)

  1. Bifunctional catalysts for the direct production of liquid fuels from syngas

    OpenAIRE

    Sartipi, S.

    2014-01-01

    Design and development of catalyst formulations that maximize the direct production of liquid fuels by combining Fischer-Tropsch synthesis (FTS), hydrocarbon cracking, and isomerization into one single catalyst particle (bifunctional FTS catalyst) have been investigated in this thesis. To achieve this aim, a second functionality (other than FTS) has to be added to the catalyst formulation to break the limitation of a classical Anderson-Schulz-Flory (ASF) distribution of FTS products. Since up...

  2. A new bifunctional hybrid nanostructure as an active platform for photothermal therapy and MR imaging

    OpenAIRE

    Mona Khafaji; Manouchehr Vossoughi; M. Reza Hormozi-Nezhad; Rassoul Dinarvand; Felix Börrnert; Azam Irajizad

    2016-01-01

    As a bi-functional cancer treatment agent, a new hybrid nanostructure is presented which can be used for photothermal therapy by exposure to one order of magnitude lower laser powers compared to similar nanostructures in addition to substantial enhancment in magnetic resonance imaging (MRI) contrast. This gold-iron oxide hybrid nanostructure (GIHN) is synthesized by a cost-effective and high yield water-based approach. The GIHN is sheilded by PEG. Therefore, it shows high hemo and biocompatib...

  3. Radiation Induced Crosslinking of Polyethylene in the Presence of Bifunctional Vinyl Monomers

    DEFF Research Database (Denmark)

    Joshi, M. S.; Singer, Klaus Albert Julius; Silverman, J.

    Several reports have been published showing that the radiation induced grafting of bifunctional vinyl monomers to low density polyethylene results in a product with an unusually high density of crosslinks. The same grafting reactions are shown to reduce the incipient gel dose by more than a facto...... of fifty. This paper is concerned with the apparent crosslinking produced by the radiation grafting of two monomers to polyethylene: acrylic acid and acrylonitrile....

  4. Bifunctional Metamaterials with Simultaneous and Independent Manipulation of Thermal and Electric Fields

    OpenAIRE

    Lan, Chuwen; Li, Bo; Zhou, Ji

    2015-01-01

    Metamaterials offer a powerful way to manipulate a variety of physical fields ranging from wave fields (electromagnetic field, acoustic field, elastic wave, etc.), static fields (static magnetic field, static electric field) to diffusive fields (thermal field, diffusive mass). However, the relevant reports and studies are usually conducted on a single physical field or functionality. In this study, we proposed and experimentally demonstrated a bifunctional metamaterial which can manipulate th...

  5. Bifunctional Catalysts for Upgrading of Biomass-Derived Oxygenates: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Allison M.; Hensley, Jesse E.; Medlin, J. Will

    2016-08-05

    Deoxygenation is an important reaction in the conversion of biomass-derived oxygenates to fuels and chemicals. A key route for biomass refining involves the production of pyrolysis oil through rapid heating of the raw biomass feedstock. Pyrolysis oil as produced is highly oxygenated, so the feasibility of this approach depends in large part on the ability to selectively deoxygenate pyrolysis oil components to create a stream of high-value finished products. Identification of catalytic materials that are active and selective for deoxygenation of pyrolysis oil components has therefore represented a major research area. One catalyst is rarely capable of performing the different types of elementary reaction steps required to deoxygenate biomass-derived compounds. For this reason, considerable attention has been placed on bifunctional catalysts, where two different active materials are used to provide catalytic sites for diverse reaction steps. Here, we review recent trends in the development of catalysts, with a focus on catalysts for which a bifunctional effect has been proposed. We summarize recent studies of hydrodeoxygenation (HDO) of pyrolysis oil and model compounds for a range of materials, including supported metal and bimetallic catalysts as well as transition-metal oxides, sulfides, carbides, nitrides, and phosphides. Particular emphasis is placed on how catalyst structure can be related to performance via molecular-level mechanisms. These studies demonstrate the importance of catalyst bifunctionality, with each class of materials requiring hydrogenation and C-O scission sites to perform HDO at reasonable rates.

  6. Comparison of Dynamical Behaviors Between Monofunctional and Bifunctional Two-Component Signaling Modules

    Science.gov (United States)

    Yang, Xiyan; Wu, Yahao; Yuan, Zhanjiang

    2015-06-01

    Two-component signaling modules exist extensively in bacteria and microbes. These modules can be, based on their distinct network structures, divided into two types: the monofunctional system (denoted by MFS) where the sensor kinase (SK) modulates only phosphorylation of the response regulator (RR), and the bifunctional system (denoted by BFS) where the SK catalyzes both phosphorylation and dephosphorylation of the RR. Here, we analyze dynamical behaviors of these two systems based on stability theory, focusing on differences between them. The analysis of the deterministic behavior indicates that there is no difference between the two modules, that is, each system has the unique stable steady state. However, there are significant differences in stochastic behavior between them. Specifically, if the mean phosphorylated SK level is kept the same for the two modules, then the variance and the Fano factor for the phosphorylated RR in the BFS are always no less than those in the MFS, indicating that bifunctionality always enhances fluctuations. The correlation between the phosphorylated SK and the phosphorylated RR in the BFS is always positive mainly due to competition between system components, but this correlation in the MFS may be positive, almost zero, or negative, depending on the ratio between two rate constants. Our overall analysis indicates that differences between dynamical behaviors of monofunctional and bifunctional signaling modules are mainly in the stochastic rather than deterministic aspect.

  7. Collagen/chitosan based two-compartment and bi-functional dermal scaffolds for skin regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Department of Plastic Surgery and Burns, Shenzhen Second People' s Hospital, Shenzhen 518035 (China); Wang, Mingbo [Key Laboratory of Biomedical Materials and Implants, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); She, Zhending [Key Laboratory of Biomedical Materials and Implants, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Shenzhen Lando Biomaterials Co., Ltd., Shenzhen 518057 (China); Fan, Kunwu; Xu, Cheng [Department of Plastic Surgery and Burns, Shenzhen Second People' s Hospital, Shenzhen 518035 (China); Chu, Bin; Chen, Changsheng [Key Laboratory of Biomedical Materials and Implants, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Shi, Shengjun, E-mail: shengjunshi@yahoo.com [The Burns Department of Zhujiang Hospital, Southern Medical University, Guangzhou 510280 (China); Tan, Rongwei, E-mail: tanrw@landobiom.com [Key Laboratory of Biomedical Materials and Implants, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Shenzhen Lando Biomaterials Co., Ltd., Shenzhen 518057 (China)

    2015-07-01

    Inspired from the sophisticated bilayer structures of natural dermis, here, we reported collagen/chitosan based two-compartment and bi-functional dermal scaffolds. Two functions refer to mediating rapid angiogenesis based on recombinant human vascular endothelial growth factor (rhVEGF) and antibacterial from gentamicin, which were encapsulated in PLGA microspheres. The gentamicin and rhVEGF encapsulated PLGA microspheres were further combined with collagen/chitosan mixtures in low (lower layer) and high (upper layer) concentrations, and molded to generate the two-compartment and bi-functional scaffolds. Based on morphology and pore structure analyses, it was found that the scaffold has a distinct double layered porous and connective structure with PLGA microspheres encapsulated. Statistical analysis indicated that the pores in the upper layer and in the lower layer have great variations in diameter, indicative of a two-compartment structure. The release profiles of gentamicin and rhVEGF exceeded 28 and 49 days, respectively. In vitro culture of mouse fibroblasts showed that the scaffold can facilitate cell adhesion and proliferation. Moreover, the scaffold can obviously inhibit proliferation of Staphylococcus aureus and Serratia marcescens, exhibiting its unique antibacterial effect. The two-compartment and bi-functional dermal scaffolds can be a promising candidate for skin regeneration. - Highlights: • The dermal scaffold is inspired from the bilayer structures of natural dermis. • The dermal scaffold has two-compartment structures. • The dermal scaffold containing VEGF and gentamicin encapsulated PLGA microspheres • The dermal scaffold can facilitate cell adhesion and proliferation.

  8. Bifunctional Perovskite Oxide Catalysts for Oxygen Reduction and Evolution in Alkaline Media.

    Science.gov (United States)

    Gupta, Shiva; Kellogg, William; Xu, Hui; Liu, Xien; Cho, Jaephil; Wu, Gang

    2016-01-01

    Oxygen electrocatalysis, namely of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), governs the performance of numerous electrochemical energy systems such as reversible fuel cells, metal-air batteries, and water electrolyzers. However, the sluggish kinetics of these two reactions and their dependency on expensive noble metal catalysts (e.g, Pt or Ir) prohibit the sustainable commercialization of these highly innovative and in-demand technologies. Bifunctional perovskite oxides have emerged as a new class of highly efficient non-precious metal catalysts (NPMC) for oxygen electrocatalysis in alkaline media. In this review, we discuss the state-of-the-art understanding of bifunctional properties of perovskites with regards to their OER/ORR activity in alkaline media and review the associated reaction mechanisms on the oxides surface and the related activity descriptors developed in the recent literature. We also summarize the present strategies to modify their electronic structure and to further improve their performance for the ORR/OER through highlighting the new concepts relating to the role of surface redox chemistry and oxygen deficiency of perovskite oxides for the ORR/OER activity. In addition, we provide a brief account of recently developed advanced perovskite-nanocarbon hybrid bifunctional catalysts with much improved performances. PMID:26247625

  9. Collagen/chitosan based two-compartment and bi-functional dermal scaffolds for skin regeneration

    International Nuclear Information System (INIS)

    Inspired from the sophisticated bilayer structures of natural dermis, here, we reported collagen/chitosan based two-compartment and bi-functional dermal scaffolds. Two functions refer to mediating rapid angiogenesis based on recombinant human vascular endothelial growth factor (rhVEGF) and antibacterial from gentamicin, which were encapsulated in PLGA microspheres. The gentamicin and rhVEGF encapsulated PLGA microspheres were further combined with collagen/chitosan mixtures in low (lower layer) and high (upper layer) concentrations, and molded to generate the two-compartment and bi-functional scaffolds. Based on morphology and pore structure analyses, it was found that the scaffold has a distinct double layered porous and connective structure with PLGA microspheres encapsulated. Statistical analysis indicated that the pores in the upper layer and in the lower layer have great variations in diameter, indicative of a two-compartment structure. The release profiles of gentamicin and rhVEGF exceeded 28 and 49 days, respectively. In vitro culture of mouse fibroblasts showed that the scaffold can facilitate cell adhesion and proliferation. Moreover, the scaffold can obviously inhibit proliferation of Staphylococcus aureus and Serratia marcescens, exhibiting its unique antibacterial effect. The two-compartment and bi-functional dermal scaffolds can be a promising candidate for skin regeneration. - Highlights: • The dermal scaffold is inspired from the bilayer structures of natural dermis. • The dermal scaffold has two-compartment structures. • The dermal scaffold containing VEGF and gentamicin encapsulated PLGA microspheres • The dermal scaffold can facilitate cell adhesion and proliferation

  10. Functional metagenomics of extreme environments.

    Science.gov (United States)

    Mirete, Salvador; Morgante, Verónica; González-Pastor, José Eduardo

    2016-04-01

    The bioprospecting of enzymes that operate under extreme conditions is of particular interest for many biotechnological and industrial processes. Nevertheless, there is a considerable limitation to retrieve novel enzymes as only a small fraction of microorganisms derived from extreme environments can be cultured under standard laboratory conditions. Functional metagenomics has the advantage of not requiring the cultivation of microorganisms or previous sequence information to known genes, thus representing a valuable approach for mining enzymes with new features. In this review, we summarize studies showing how functional metagenomics was employed to retrieve genes encoding for proteins involved not only in molecular adaptation and resistance to extreme environmental conditions but also in other enzymatic activities of biotechnological interest. PMID:26901403

  11. The Structure of Aquifex aeolicus Ribosomal Protein S8 Reveals a Unique Subdomain That Contributes to Extremely-Tight Association With 16S rRNA

    OpenAIRE

    Menichelli, Elena; Edgcomb, Stephen P.; Recht, Michael I.; Williamson, James R.

    2011-01-01

    The assembly of ribonucleoprotein complexes occurs in a broad range of conditions, but the principles that promote assembly and allow function at high temperature are poorly understood. The ribosomal protein S8 from the hyperthemophilic bacterium Aquifex aeolicus (AS8) is unique in that there is a 41 residue insertion in the consensus S8 sequence. In addition, AS8 exhibits an unusually-high affinity for the 16S ribosomal RNA (rRNA), characterized by a picomolar dissociation constant that is a...

  12. New approach to immunochemical determinations for triclopyr and 3,5,6-trichloro-2-pyridinol by using a bifunctional hapten, and evaluation of polyclonal antiserum.

    Science.gov (United States)

    Watanabe, Eiki; Hoshino, Ryoko; Kanzaki, Yukiko; Tokumoto, Hiroshi; Kubo, Hiroaki; Nakazawa, Hiroyuki

    2002-06-19

    The present work describes the design and synthesis of the structurally unique hapten, "bifunctional hapten", to produce a group-specific polyclonal antiserum to triclopyr and 3,5,6-trichloro-2-pyridinol. A bifunctional hapten was designed and synthesized by conjugating commercially available Nepsilon-2,4-dinitrophenyl (DNP)-L-lysine to triclopyr, and then coupling this to carrier proteins such as bovine serum albumin (BSA). The synthesized bifunctional hapten greatly raised the antiserum titer in comparison with that of the conventional hapten, triclopyr. Antiserum with a sufficiently high titer to provide the determinations of targeted compounds was obtained only 63 days after the primary immunization. The obtained antiserum showed the highest affinity to triclopyr (IC(50) = 3.5 nM) and 3,5,6-trichloro-2-pyridinol (IC(50) = 5.1 nM) in homologous ELISA. The cross-reactivities to various agrochemicals and some chlorinated phenolic compounds were determined. Significant cross-reactivity was found to the herbicide 2,4,5-T. The antiserum reacted to both triclopyr and its metabolite. Assay sensitivity was evaluated for effects of various assay conditions, including pH value and concentrations of organic solvents and detergents. Under optimized assay conditions, the quantitative working range of triclopyr ELISA was from 0.1 to 5.2 ng/mL with a limit of detection (LOD) of 0.037 ng/mL, and an IC(50) of 0.72 ng/mL. On the other hand, the quantitative working range of 3,5,6-trichloro-2-pyridinol ELISA was from 0.13 to 6.0 ng/mL with a LOD of 0.052 ng/mL, and an IC(50) of 0.95 ng/mL. Water samples fortified with triclopyr or its metabolite at 1, 5, and 10 ng/mL were directly analyzed without extraction and cleanup by the proposed ELISA. The mean recovery was 101.6%, and the mean coefficient of variation (CV) was 7.1% in the case of the triclopyr ELISA. In the case of the 3,5,6-trichloro-2-pyridinol ELISA, the mean recovery was 99.8%, and the mean CV was 9.5%. The proposed

  13. Increased serum and musculotendinous fibrogenic proteins following persistent low-grade inflammation in a rat model of long-term upper extremity overuse.

    Directory of Open Access Journals (Sweden)

    Helen G L Gao

    Full Text Available We examined the relationship between grip strength declines and muscle-tendon responses induced by long-term performance of a high-repetition, low-force (HRLF reaching task in rats. We hypothesized that grip strength declines would correlate with inflammation, fibrosis and degradation in flexor digitorum muscles and tendons. Grip strength declined after training, and further in weeks 18 and 24, in reach limbs of HRLF rats. Flexor digitorum tissues of reach limbs showed low-grade increases in inflammatory cytokines: IL-1β after training and in week 18, IL-1α in week 18, TNF-α and IL-6 after training and in week 24, and IL-10 in week 24, with greater increases in tendons than muscles. Similar cytokine increases were detected in serum with HRLF: IL-1α and IL-10 in week 18, and TNF-α and IL-6 in week 24. Grip strength correlated inversely with IL-6 in muscles, tendons and serum, and TNF-α in muscles and serum. Four fibrogenic proteins, TGFB1, CTGF, PDGFab and PDGFbb, and hydroxyproline, a marker of collagen synthesis, increased in serum in HRLF weeks 18 or 24, concomitant with epitendon thickening, increased muscle and tendon TGFB1 and CTGF. A collagenolytic gelatinase, MMP2, increased by week 18 in serum, tendons and muscles of HRLF rats. Grip strength correlated inversely with TGFB1 in muscles, tendons and serum; with CTGF-immunoreactive fibroblasts in tendons; and with MMP2 in tendons and serum. Thus, motor declines correlated with low-grade systemic and musculotendinous inflammation throughout task performance, and increased fibrogenic and degradative proteins with prolonged task performance. Serum TNF-α, IL-6, TGFB1, CTGF and MMP2 may serve as serum biomarkers of work-related musculoskeletal disorders, although further studies in humans are needed.

  14. Preparation and characteristics of Fe3O4-YVO4:Eu3+ bifunctional magnetic-luminescent nanocomposites

    International Nuclear Information System (INIS)

    Graphical abstract: Highlights: → Bifunctional magnetic-luminescent nanocomposites with Fe3O4 nanoparticles as the core and YVO4:Eu3+ as the shell. → A cubic spinel structrue of Fe3O4 core and a tetragonal phase of YVO4 shell were obtained. → The nanocomposites displayed a strong red emission and superparamagnetic behavior at room temperature. - Abstract: A facile direct precipitation method has been developed for the synthesis of bifunctional magnetic-luminescent nanocomposites with Fe3O4 nanoparticles as the core and YVO4:Eu3+ as the shell. Transmission electron microscopy (TEM) images revealed that the obtained bifunctional nanocomposites had a core-shell structure and a spherical morphology. The average size was ∼150 nm, and the thickness of the shell was ∼15 nm. The X-ray diffraction (XRD) patterns showed that a cubic spinel structure of Fe3O4 core and a tetragonal phase of YVO4 shell were obtained. Fourier transform infrared (FT-IR) spectra confirmed that the YVO4:Eu3+ had been successfully deposited on the surface of Fe3O4 nanoparticles. Photoluminescence (PL) spectra indicated that the nanocomposites displayed a strong red characteristic emission of Eu3+. Magnetic measurements showed that the obtained bifunctional nanocomposites exhibited superparamagnetic behavior at room temperature. Therefore, the bifunctional nanocomposites are expected to develop many potential applications in biomedical fields.

  15. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  16. Deficiently Extremal Gorenstein Algebras

    Indian Academy of Sciences (India)

    Pavinder Singh

    2011-08-01

    The aim of this article is to study the homological properties of deficiently extremal Gorenstein algebras. We prove that if / is an odd deficiently extremal Gorenstein algebra with pure minimal free resolution, then the codimension of / must be odd. As an application, the structure of pure minimal free resolution of a nearly extremal Gorenstein algebra is obtained.

  17. Nanostructured Perovskite LaCo1-xMnxO3 as Bifunctional Catalysts for Rechargeable Metal-Air Batteries

    Science.gov (United States)

    Ge, Xiaoming; Li, Bing; Wuu, Delvin; Sumboja, Afriyanti; An, Tao; Hor, T. S. Andy; Zong, Yun; Liu, Zhaolin

    2015-09-01

    Bifunctional catalyst that is active for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the most important components of rechargeable metal-air batteries. Nanostructured perovskite bifunctional catalysts comprising La, Co and Mn(LaCo1-xMnxO3, LCMO) are synthesized by hydrothermal methods. The morphology, structure and electrochemical activity of the perovskite bifunctional catalysts are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and rotating disk electrode (RDE) techniques. Nanorod, nanodisc and nanoparticle are typical morphologies of LCMO. The electrocatalytic activity of LCMO is significantly improved by the addition of conductive materials such as carbon nanotube. To demonstrate the practical utilization, LCMO in the composition of LaCo0.8Mn0.2O3(LCMO82) is used as air cathode catalysts for rechargeable zinc-air batteries. The battery prototype can sustain 470 h or 40 discharge-charge cycles equivalent.

  18. Mechanical characterization of a bifunctional Tetronic hydrogel adhesive for soft tissues.

    Science.gov (United States)

    Sanders, Lindsey; Stone, Roland; Webb, Kenneth; Mefford, Thompson; Nagatomi, Jiro

    2015-03-01

    Although a number of tissue adhesives and sealants for surgical use are currently available, attaining a useful balance in high strength, high compliance, and low swelling has proven difficult. Recent studies have demonstrated that a four-arm poly(propylene oxide)-poly(ethylene oxide) block copolymer, Tetronic, can be chemically modified to form a hydrogel tissue adhesive (Cho et al., Acta Biomater 2012;8:2223-2232; Barrett et al., Adv Health Mater 2012;1-11; Balakrishnan, Evaluating mechanical performance of hydrogel-based adhesives for soft tissue applications. Clemson University, All Theses, Paper 1574: Tiger Prints; 2013). Building on the success of these studies, this study explored bifunctionalization of Tetronic with acrylates for chemical crosslinking of the hydrogel and N-hydroxysuccinimide (NHS) for reaction with tissue amines. The adhesive bond strengths of various uni and bifunctional Tetronic blends (T1107 ACR: T1107 ACR/NHS) determined by lap shear testing ranged between 8 and 74 kPa, with the 75:25 (T1107 ACR: T1107 ACR/NHS) blend displaying the highest value. These results indicated that addition of NHS led to improvement of tissue bond strength over acrylation alone. Furthermore, ex vivo pressure tests using the rat bladder demonstrated that the bifunctional Tetronic adhesive exhibited high compliance and maintained pressures under hundreds of filling and emptying cycles. Together, the results of this study provided evidence that the bifunctional Tetronic adhesive with a proper blend ratio may be used to achieve an accurate balance in bulk and tissue bond strengths, as well as the compliance and durability for soft tissue such as the bladder. PMID:25111445

  19. Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones

    Science.gov (United States)

    Di Mola, Antonia; Tiffner, Maximilian; Scorzelli, Francesco; Palombi, Laura; Filosa, Rosanna; De Caprariis, Paolo

    2015-01-01

    Summary New bifunctional chiral ammonium salts were investigated in an asymmetric cascade synthesis of a key building block for a variety of biologically relevant isoindolinones. With this chiral compound in hand, the development of further transformations allowed for the synthesis of diverse derivatives of high pharmaceutical value, such as the Belliotti (S)-PD172938 and arylated analogues with hypnotic sedative activity, obtained in good overall total yield (50%) and high enantiomeric purity (95% ee). The synthetic routes developed herein are particularly convenient in comparison with the current methods available in literature and are particularly promising for large scale applications. PMID:26734105

  20. Tunable catalytic properties of bi-functional mixed oxides in ethanol conversion to high value compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Karthikeyan K.; Gray, Michel J.; Job, Heather M.; Smith, Colin D.; Wang, Yong

    2016-04-10

    tA highly versatile ethanol conversion process to selectively generate high value compounds is pre-sented here. By changing the reaction temperature, ethanol can be selectively converted to >C2alcohols/oxygenates or phenolic compounds over hydrotalcite derived bi-functional MgO–Al2O3cata-lyst via complex cascade mechanism. Reaction temperature plays a role in whether aldol condensationor the acetone formation is the path taken in changing the product composition. This article containsthe catalytic activity comparison between the mono-functional and physical mixture counterpart to thehydrotalcite derived mixed oxides and the detailed discussion on the reaction mechanisms.

  1. Bifunctional Organic Polymeric Catalysts with a Tunable Acid-Base Distance and Framework Flexibility

    Science.gov (United States)

    Chen, Huanhui; Wang, Yanan; Wang, Qunlong; Li, Junhui; Yang, Shiqi; Zhu, Zhirong

    2014-09-01

    Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers to be adjacent to acidic monomers, and by changing the chain length of acidic monomers. In a standard test reaction for the aldol condensation of 4-nitrobenzaldehyde with acetone, the catalysts showed good reusability upon recycling and maintained relatively high conversion percentage.

  2. Bifunctional Brønsted Base Catalyzes Direct Asymmetric Aldol Reaction of α-Keto Amides.

    Science.gov (United States)

    Echave, Haizea; López, Rosa; Palomo, Claudio

    2016-03-01

    The first enantioselective direct cross-aldol reaction of α-keto amides with aldehydes, mediated by a bifunctional ureidopeptide-based Brønsted base catalyst, is described. The appropriate combination of a tertiary amine base and an aminal, and urea hydrogen-bond donor groups in the catalyst structure promoted the exclusive generation of the α-keto amide enolate which reacted with either non-enolizable or enolizable aldehydes to produce highly enantioenriched polyoxygenated aldol adducts without side-products resulting from dehydration, α-keto amide self-condensation, aldehyde enolization, and isotetronic acid formation. PMID:26835655

  3. The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

    DEFF Research Database (Denmark)

    Rautengarten, Carsten; Ebert, Berit; Moreno, Ignacio;

    2014-01-01

    are specifically presumed to deliver the diverse array of nucleotide sugars found in plants. This study has developed a novel approach that enabled functional characterization of six bifunctional UDP-rhamnose (Rha)/UDP-galactose (Gal) transporters from Arabidopsis. An analysis of loss-of-function and...... overexpression lines for two of these transporters identified biochemical alterations supporting their roles in the biosynthesis of Rha- and Gal-containing polysaccharides. Thus, cell wall polysaccharide biosynthesis in the Golgi apparatus of plants is likely also regulated by substrate transport mechanisms....

  4. Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones.

    Science.gov (United States)

    Di Mola, Antonia; Tiffner, Maximilian; Scorzelli, Francesco; Palombi, Laura; Filosa, Rosanna; De Caprariis, Paolo; Waser, Mario; Massa, Antonio

    2015-01-01

    New bifunctional chiral ammonium salts were investigated in an asymmetric cascade synthesis of a key building block for a variety of biologically relevant isoindolinones. With this chiral compound in hand, the development of further transformations allowed for the synthesis of diverse derivatives of high pharmaceutical value, such as the Belliotti (S)-PD172938 and arylated analogues with hypnotic sedative activity, obtained in good overall total yield (50%) and high enantiomeric purity (95% ee). The synthetic routes developed herein are particularly convenient in comparison with the current methods available in literature and are particularly promising for large scale applications. PMID:26734105

  5. An efficient bifunctional electrocatalyst for water splitting based on cobalt phosphide

    Science.gov (United States)

    Yang, Libin; Qi, Honglan; Zhang, Chengxiao; Sun, Xuping

    2016-06-01

    The development of highly efficient electrocatalysts for water splitting is critical for various renewable-energy technologies. In this letter, we demonstrate a cobalt phosphide nanowire array grown on a Ti mesh (CoP/TM) behaving as a bifunctional electrocatalyst for water splitting. The CoP/TM electrode delivers 10 mA cm‑2 at an overpotential of 72 mV for the hydrogen evolution reaction (HER) and 310 mV for the oxygen evolution reaction (OER) in 1.0 M KOH. Furthermore, its corresponding two-electrode alkaline electrolyzer displays 10 mA cm‑2 at 1.64 V.

  6. Cobalt nanoparticles embedded in N-doped carbon as an efficient bifunctional electrocatalyst for oxygen reduction and evolution reactions

    Science.gov (United States)

    Su, Yunhe; Zhu, Yihua; Jiang, Hongliang; Shen, Jianhua; Yang, Xiaoling; Zou, Wenjian; Chen, Jianding; Li, Chunzhong

    2014-11-01

    Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those of Pt/C and most of the non-precious metal catalysts in previous studies. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and the efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those

  7. Preparation of Pt/Irx(IrO2)10 - x bifunctional oxygen catalyst for unitized regenerative fuel cell

    Science.gov (United States)

    Kong, Fan-Dong; Zhang, Sheng; Yin, Ge-Ping; Zhang, Na; Wang, Zhen-Bo; Du, Chun-Yu

    2012-07-01

    Bifunctional Pt/Irx(IrO2)10 - x (x oxygen reduction reaction (ORR) (21.71 mA mg-1 at 0.85 V). Meanwhile, considerably high activity towards oxygen evolution reaction (OER) (42.35 mA mg-1 at 1.55 V) is also observed for Pt/Ir3(IrO2)7 catalyst. Kinetic analyses indicate that ORR on Pt/Ir3(IrO2)7 catalyst follows four-electron mechanism. This work opens a new way to fabricate efficient bifunctional oxygen catalyst for URFC.

  8. A central role for bifunctional aspartate/prephenate aminotransferase in the biosynthesis of amino acids in plant plastids.

    OpenAIRE

    El-Azaz, Jorge; Cánovas, Francisco M.; de la Torre, Fernando; Ávila, Concepción

    2014-01-01

    A central role for bifunctional aspartate/prephenate aminotransferase in the biosynthesis of amino acids in plant plastids. Fernando de la Torre, Jorge El-Azaz, Concepción Ávila, Francisco M. Cánovas Departamento de Biología Molecular y Bioquímica. Universidad de Málaga. Bifunctional aspartate/prephenate aminotransferases (AAT/PAT) are plastid-located enzymes encoded by a single locus in all reported plants, which develop two different enzymatic activities: aspartate aminotransferas...

  9. Characterization of bifunctional L-glutathione synthetases from Actinobacillus pleuropneumoniae and Actinobacillus succinogenes for efficient glutathione biosynthesis.

    Science.gov (United States)

    Yang, Jianhua; Li, Wei; Wang, Dezheng; Wu, Hui; Li, Zhimin; Ye, Qin

    2016-07-01

    Glutathione (GSH), an important bioactive substance, is widely applied in pharmaceutical and food industries. In this work, two bifunctional L-glutathione synthetases (GshF) from Actinobacillus pleuropneumoniae (GshFAp) and Actinobacillus succinogenes (GshFAs) were successfully expressed in Escherichia coli BL-21(DE3). Similar to the GshF from Streptococcus thermophilus (GshFSt), GshFAp and GshFAs can be applied for high titer GSH production because they are less sensitive to end-product inhibition (Ki values 33 and 43 mM, respectively). The active catalytic forms of GshFAs and GshFAp are dimers, consistent with those of GshFPm (GshF from Pasteurella multocida) and GshFSa (GshF from Streptococcus agalactiae), but are different from GshFSt (GshF from S. thermophilus) which is an active monomer. The analysis of the protein sequences and three dimensional structures of GshFs suggested that the binding sites of GshFs for substrates, L-cysteine, L-glutamate, γ-glutamylcysteine, adenosine-triphosphate, and glycine are highly conserved with only very few differences. With sufficient supply of the precursors, the recombinant strains BL-21(DE3)/pET28a-gshFas and BL-21(DE3)/pET28a-gshFap were able to produce 36.6 and 34.1 mM GSH, with the molar yield of 0.92 and 0.85 mol/mol, respectively, based on the added L-cysteine. The results showed that GshFAp and GshFAs are potentially good candidates for industrial GSH production. PMID:26996628

  10. Allosteric Switching by Mutually Exclusive Folding of Protein Domains

    OpenAIRE

    Radley, Tracy L.; Markowska, Anna I.; Bettinger, Blaine T.; Ha, Jeung-Hoi; Loh, Stewart N.

    2003-01-01

    Many proteins are built from structurally and functionally distinct and domains. A major goal is to understand how conformational change transmits information between domains in order to achieve biological activity. A two-domain, bi-functional fusion protein has been designed so that the mechanical stress imposed by the folded structure of one subunit causes the other subunit to unfold, and vice versa. The construct consists of ubiquitin inserted into a surface loop of barnase. The distance b...

  11. Large-scale Generation of Patterned Bubble Arrays on Printed Bi-functional Boiling Surfaces

    Science.gov (United States)

    Choi, Chang-Ho; David, Michele; Gao, Zhongwei; Chang, Alvin; Allen, Marshall; Wang, Hailei; Chang, Chih-Hung

    2016-04-01

    Bubble nucleation control, growth and departure dynamics is important in understanding boiling phenomena and enhancing nucleate boiling heat transfer performance. We report a novel bi-functional heterogeneous surface structure that is capable of tuning bubble nucleation, growth and departure dynamics. For the fabrication of the surface, hydrophobic polymer dot arrays are first printed on a substrate, followed by hydrophilic ZnO nanostructure deposition via microreactor-assisted nanomaterial deposition (MAND) processing. Wettability contrast between the hydrophobic polymer dot arrays and aqueous ZnO solution allows for the fabrication of heterogeneous surfaces with distinct wettability regions. Heterogeneous surfaces with various configurations were fabricated and their bubble dynamics were examined at elevated heat flux, revealing various nucleate boiling phenomena. In particular, aligned and patterned bubbles with a tunable departure frequency and diameter were demonstrated in a boiling experiment for the first time. Taking advantage of our fabrication method, a 6 inch wafer size heterogeneous surface was prepared. Pool boiling experiments were also performed to demonstrate a heat flux enhancement up to 3X at the same surface superheat using bi-functional surfaces, compared to a bare stainless steel surface.

  12. Structural basis for the bifunctionality of fructose-1,6-bisphosphate aldolase/phosphatase.

    Science.gov (United States)

    Fushinobu, Shinya; Nishimasu, Hiroshi; Hattori, Daiki; Song, Hyun-Jin; Wakagi, Takayoshi

    2011-10-27

    Enzymes catalyse specific reactions and are essential for maintaining life. Although some are referred to as being bifunctional, they consist of either two distinct catalytic domains or a single domain that displays promiscuous substrate specificity. Thus, one enzyme active site is generally responsible for one biochemical reaction. In contrast to this conventional concept, archaeal fructose-1,6-bisphosphate (FBP) aldolase/phosphatase (FBPA/P) consists of a single catalytic domain, but catalyses two chemically distinct reactions of gluconeogenesis: (1) the reversible aldol condensation of dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GA3P) to FBP; (2) the dephosphorylation of FBP to fructose-6-phosphate (F6P). Thus, FBPA/P is fundamentally different from ordinary enzymes whose active sites are responsible for a specific reaction. However, the molecular mechanism by which FBPA/P achieves its unusual bifunctionality remains unknown. Here we report the crystal structure of FBPA/P at 1.5-Å resolution in the aldolase form, where a critical lysine residue forms a Schiff base with DHAP. A structural comparison of the aldolase form with a previously determined phosphatase form revealed a dramatic conformational change in the active site, demonstrating that FBPA/P metamorphoses its active-site architecture to exhibit dual activities. Thus, our findings expand the conventional concept that one enzyme catalyses one biochemical reaction. PMID:21983966

  13. Subnanometer Cobalt-Hydroxide-Anchored N-Doped Carbon Nanotube Forest for Bifunctional Oxygen Catalyst.

    Science.gov (United States)

    Kim, Ji Eun; Lim, Joonwon; Lee, Gil Yong; Choi, Sun Hee; Maiti, Uday Narayan; Lee, Won Jun; Lee, Ho Jin; Kim, Sang Ouk

    2016-01-27

    Electrochemical oxygen redox reactions are the crucial elements for energy conversion and storage including fuel cells and metal air batteries. Despite tremendous research efforts, developing high-efficient, low-cost, and durable bifunctional oxygen catalysts remains a major challenge. We report a new class of hybrid material consisting of subnanometer thick amorphous cobalt hydroxide anchored on NCNT as a durable ORR/OER bifunctional catalyst. Although amorphous cobalt species-based catalysts are known as good OER catalysts, hybridizing with NCNT successfully enhanced ORR activity by promoting a 4e reduction pathway. Abundant charge carriers in amorphous cobalt hydroxide are found to trigger the superior OER activity with high current density and low Tafel slope as low as 36 mV/decade. A remarkably high OER turnover frequency (TOF) of 2.3 s(-1) at an overpotential of 300 mV was obtained, one of the highest values reported so far. Moreover, the catalytic activity was maintained over 120 h of cycling. The unique subnanometer scale morphology of amorphous hydroxide cobalt species along with intimate cobalt species-NCNT interaction minimizes the deactivation of catalyst during prolonged repeated cycles. PMID:26766495

  14. Highly Efficient and Robust Nickel Phosphides as Bifunctional Electrocatalysts for Overall Water-Splitting.

    Science.gov (United States)

    Li, Jiayuan; Li, Jing; Zhou, Xuemei; Xia, Zhaoming; Gao, Wei; Ma, Yuanyuan; Qu, Yongquan

    2016-05-01

    To search for the efficient non-noble metal based and/or earth-abundant electrocatalysts for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, we report nickel phosphide (NixPy) catalysts with the controllable phases as the efficient bifunctional catalysts for water electrolysis. The phases of NixPy were determined by the temperatures of the solid-phase reaction between the ultrathin Ni(OH)2 plates and NaH2PO2·H2O. The NixPy with the richest Ni5P4 phase synthesized at 325 °C (NixPy-325) delivered efficient and robust catalytic performance for hydrogen evolution reaction (HER) in the electrolytes with a wide pH range. The NixPy-325 catalysts also exhibited a remarkable performance for oxygen evolution reaction (OER) in a strong alkaline electrolyte (1.0 M KOH) due to the formation of surface NiOOH species. Furthermore, the bifunctional NixPy-325 catalysts enabled a highly performed overall water-splitting with ∼100% Faradaic efficiency in 1.0 M KOH electrolyte, in which a low applied external potential of 1.57 V led to a stabilized catalytic current density of 10 mA/cm(2) over 60 h. PMID:27064172

  15. Introducing new 99m-Tc-bifunctional radiopharmaceutical containing dithiosemicarbazone chelate group

    International Nuclear Information System (INIS)

    In our attempt to develop 99m-Tc-Bifunctional Radiopharmaceuticals (BR) of biomolecules, our interest has been focussed on the di-thiosemicarbazone chelating group (DTS); its coordination moiety allows a 1:1 complex with a tetravalent TcO2+, generating a neutral chelate of great stability and compactness. For ligand containing S N coordination, satisfactory labeling has been achieved at pH 5-6, in the presence of Sn-Resin. Based on the above mentioned, the use of DTS is tested in two different modalities by selecting glucose and albumin as the biomolecules of interest. The synthesis of a glucosone-1,2-bis (thiosemicarbazone) (Glu-DTS) and upon its labelling, the 99m-Tc-Glu-DTS was tested in animals. Scintigraphic studies revealed high activity in the brain and heart. This result offered strong support for the use of DTS as a bifunctional chelating agent (BCA). DTS-COOH and DTS-NH2 were synthesized for the coupling with biomolecules. As a first trial, they were coupled with albumin and their functionality proven. The results gathered provided conclusive evidence for the remarkable characteristic of DTS as a basic structure for the development of 99m-Tc-RP

  16. Construction of a bifunctional enzyme fusion for the combined determination of biogenic amines in foods.

    Science.gov (United States)

    Lee, Jae-Ick; Jang, Jun-Hyuck; Yu, Mi-Ji; Kim, Young-Wan

    2013-09-25

    Biogenic amines (BAs) are a group of low-molecular-mass organic bases derived from free amino acids. Due to the undesirable effects of BAs on human health, amine oxidase-based detection methods for BAs in foods have been developed. Here, we developed a bifunctional enzyme fusion (MAPO) using a Cu(2+)-containing monoamine oxidase (AMAO2) and a flavin adenine dinucleotide-containing putrescine oxidase (APUO) from Arthrobacter aurescens. It was necessary to activate MAPO with supplementary Cu(2+) ions, leading to a 6- to 12-fold improvement in catalytic efficiency (kcat/KM) for monoamines. The optimal temperatures of Cu(2+)-activated MAPO (cMAPO) for both tyramine and putrescine were 50 °C, and the optimal pH values for tyramine and putrescine were pH 7.0 and pH 8.0, respectively, consistent with those of AMAO2 and APUO, respectively. The cMAPO showed relative specific activities of 100, 99, 32, and 32 for 2-phenylethylamine, tyramine, histamine, and putrescine, respectively. The tyramine-equivalent BA contents of fermented soybean pastes by cMAPO were more than 90% of the total BA determined by HPLC. In conclusion, cMAPO is fully bifunctional toward biogenic monoamines and putrescine, allowing the combined determination of multiple BAs in foods. This colorimetric determination method could be useful for point-of-care testing to screen safety-guaranteed products prior to instrumental analyses. PMID:24001036

  17. Bifunctional composite microspheres of silica/lanthanide-polyoxometalates/Au: Study on luminescence and catalytic properties

    International Nuclear Information System (INIS)

    In this paper, the synthesis and properties of composite silica microspheres grafted with gold nanoparticles and lanthanide-polyoxometalates are described. This synthesis employs polyethyleneimine as the crosslink polymer to immobilize the Au nanoparticles and lanthanide-polyoxometalates on silica spheres, which results in the formation of bifunctional composite microspheres of silica/lanthanide-polyoxometalates/Au. The composite material was found to be catalytically active in the oxidation of styrene, and benzaldehyde and styrene oxide were the main products. Catalyzed oxidation of styrene demonstrates the size-dependent activity of catalysts and the smaller catalyst shows the higher selectivity. Moreover, the composite particles show bright red luminescence under UV light, which could be seen by naked eyes. The luminescence properties of composite material and the effect of Au nanoparticles on the luminescence of Eu ion were investigated, and energy could be more effectively transferred from ligand to lanthanide ion when Au nanoparticles were grafted on silica spheres. The integration of luminescent components and Au particles makes it possible to label catalyst and monitor the catalyzed reactions. - Highlights: • The bifunctional composite microspheres were fabricated. • Both polyoxometalates and Au nanoparticles could be grafted on silica spheres. • The composite particles exhibit the excellent luminescence and catalytic activity. • The Au nanoparticles affect the luminescence properties of Eu3+ ions

  18. Determining the Origin of Half-bandgap-voltage Electroluminescence in Bifunctional Rubrene/C60 Devices

    Science.gov (United States)

    Chen, Qiusong; Jia, Weiyao; Chen, Lixiang; Yuan, De; Zou, Yue; Xiong, Zuhong

    2016-01-01

    Lowering the driving voltage of organic light-emitting diodes (OLEDs) is an important approach to reduce their energy consumption. We have fabricated a series of bifunctional devices (OLEDs and photovoltaics) using rubrene and fullerene (C60) as the active layer, in which the electroluminescence threshold voltage(~1.1 V) was half the value of the bandgap of rubrene. Magneto-electroluminescence (MEL) response of planner heterojunction diodes exhibited a small increase in response to a low magnetic field strength (20 mT). When a hole-transport layer with a low mobility was included in these devices, the MEL response reversed in shape, and simultaneously, the EL threshold voltage became larger than the bandgap voltage. When bulk heterojunction device was examined, the amplitude of MEL curves presented an anomalous voltage-dependence. Following an analysis of the MEL responses of these devices, we proposed that the EL of half-bandgap-voltage device originated from bimolecular triplet-triplet annihilation in the rubrene film, rather than from singlet excitons that formed via an interface auger recombination. This work provides critical insight into the mechanisms of OLED emission and will help advance the applications of bifunctional devices. PMID:27142285

  19. Determining the Origin of Half-bandgap-voltage Electroluminescence in Bifunctional Rubrene/C60 Devices.

    Science.gov (United States)

    Chen, Qiusong; Jia, Weiyao; Chen, Lixiang; Yuan, De; Zou, Yue; Xiong, Zuhong

    2016-01-01

    Lowering the driving voltage of organic light-emitting diodes (OLEDs) is an important approach to reduce their energy consumption. We have fabricated a series of bifunctional devices (OLEDs and photovoltaics) using rubrene and fullerene (C60) as the active layer, in which the electroluminescence threshold voltage(~1.1 V) was half the value of the bandgap of rubrene. Magneto-electroluminescence (MEL) response of planner heterojunction diodes exhibited a small increase in response to a low magnetic field strength (20 mT). When a hole-transport layer with a low mobility was included in these devices, the MEL response reversed in shape, and simultaneously, the EL threshold voltage became larger than the bandgap voltage. When bulk heterojunction device was examined, the amplitude of MEL curves presented an anomalous voltage-dependence. Following an analysis of the MEL responses of these devices, we proposed that the EL of half-bandgap-voltage device originated from bimolecular triplet-triplet annihilation in the rubrene film, rather than from singlet excitons that formed via an interface auger recombination. This work provides critical insight into the mechanisms of OLED emission and will help advance the applications of bifunctional devices. PMID:27142285

  20. Extremity x-ray

    Science.gov (United States)

    An extremity x-ray is an image of the hands, wrist, feet, ankle, leg, thigh, forearm humerus or upper arm, hip, shoulder ... term "extremity" often refers to a human limb. X-rays are a form of radiation that passes through ...

  1. Classifying Returns as Extreme

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    2014-01-01

    I consider extreme returns for the stock and bond markets of 14 EU countries using two classification schemes: One, the univariate classification scheme from the previous literature that classifies extreme returns for each market separately, and two, a novel multivariate classification scheme tha...

  2. Bivariate extreme value distributions

    Science.gov (United States)

    Elshamy, M.

    1992-01-01

    In certain engineering applications, such as those occurring in the analyses of ascent structural loads for the Space Transportation System (STS), some of the load variables have a lower bound of zero. Thus, the need for practical models of bivariate extreme value probability distribution functions with lower limits was identified. We discuss the Gumbel models and present practical forms of bivariate extreme probability distributions of Weibull and Frechet types with two parameters. Bivariate extreme value probability distribution functions can be expressed in terms of the marginal extremel distributions and a 'dependence' function subject to certain analytical conditions. Properties of such bivariate extreme distributions, sums and differences of paired extremals, as well as the corresponding forms of conditional distributions, are discussed. Practical estimation techniques are also given.

  3. Pd(0)@UiO-68-AP: chelation-directed bifunctional heterogeneous catalyst for stepwise organic transformations.

    Science.gov (United States)

    Li, Yan-An; Yang, Song; Liu, Qi-Kui; Chen, Gong-Jun; Ma, Jian-Ping; Dong, Yu-Bin

    2016-05-01

    A bifunctional heterogeneous catalyst Pd(0)@UiO-68-AP based on a chelation-directed post-synthetic approach is reported. It exhibits typical heterogeneous catalytic behaviour and can promote benzyl alcohol oxidiation-Knoevenagel condensation in a stepwise way. PMID:27035589

  4. Complexation and biodistribution study of 111In complexes of bifunctional phosphinic acid analogues of H4DOTA

    Czech Academy of Sciences Publication Activity Database

    Forsterová, Michaela; Zimová, Jana; Petrík, M.; Lázníček, M.; Lázníčková, A.; Hermann, P.; Melichar, František

    2007-01-01

    Roč. 2, č. 337 (2007), s. 34-34. ISSN 1619-7070 R&D Projects: GA AV ČR 1QS100480501 Institutional research plan: CEZ:AV0Z10480505 Keywords : bifunctional H4DOTA ligands * phosphinic acid analogues, * complexation of 111In Subject RIV: FR - Pharmacology ; Medidal Chemistry

  5. Bifunctional, Carbon-Free Nickel/Cobalt-Oxide Cathodes for Lithium-Air Batteries with an Aqueous Alkaline Electrolyte

    International Nuclear Information System (INIS)

    Highlights: • High activity bi-functional catalyst combination for ORR and OER . • An optimum ratio of high active bi-functional catalysts was found. • Novel electrodes without carbon to avoid carbon corrosion during OER mode. • EIS model for OER describes influence of a growing oxide layers. • Long-term test exhibited an excellent long-term stability over 1200 cycles. - Abstract: Lithium-air batteries with an aqueous alkaline electrolyte promise a very high practical energy density and capacity. These batteries are mainly limited by high overpotentials on the bifunctional cathode during charge and discharge. To reduce overpotentials the bifunctional cathode of such batteries must be improved significantly. Nickel is relatively inexpensive and has a good catalytic activity in alkaline media. Co3O4 was found to be a promising metal oxide catalyst for oxygen evolution in alkaline media but it has a low electronic conductivity. On the other hand since nickel has a good electronic conductivity Co3O4 can be added to pure nickel electrodes to enhance performance due to a synergetic effect. Due to the poor stability of carbon materials at high anodic potentials, gas diffusion electrodes were prepared without carbon to improve especially long-term stability. Gas diffusion electrodes were electrochemically investigated in a half cell. In addition, cyclic voltammogrametry (CV) and electrochemical impedance spectroscopy (EIS) were carried out. SEM was used for the physical and morphological investigations. Investigations showed that electrodes containing 20 wt.% Co3O4 exhibited the highest performance

  6. Scalable Fabrication of Nanoporous Carbon Fiber Films as Bifunctional Catalytic Electrodes for Flexible Zn-Air Batteries.

    Science.gov (United States)

    Liu, Qin; Wang, Yaobing; Dai, Liming; Yao, Jiannian

    2016-04-01

    A flexible nanoporous carbon-fiber film for wearable electronics is prepared by a facile and scalable method through pyrolysis of electrospun polyimide. It exhibits excellent bifunctional electrocatalytic activities for oxygen reduction and oxygen evolution. Flexible rechargeable zinc-air batteries based on the carbon-fiber film show high round-trip efficiency and mechanical stability. PMID:26914270

  7. A bifunctional α-amylase/trypsin inhibitor from pigeonpea seeds: Purification, biochemical characterization and its bio-efficacy against Helicoverpa armigera.

    Science.gov (United States)

    Gadge, Prafull P; Wagh, Sandip K; Shaikh, Faiyaz K; Tak, Rajesh D; Padul, Manohar V; Kachole, Manvendra S

    2015-11-01

    This paper evaluates α-amylase inhibitor (α-AI) mediated defense of pigeonpea against Helicoverpa armigera. A bifunctional α-amylase/trypsin inhibitor was purified from the seeds of pigeonpea by native liquid phase isoelectric focusing (N-LP-IEF), affinity chromatography and preparative electrophoresis. Its in-vivo and in-vitro interaction with midgut amylases of H. armigera was studied along with growth inhibitory activity. One and two dimensional (2D) zymographic analyses revealed that the purified inhibitor is dimeric glycoprotein (60.2kDa and 56kDa) exist in a multi-isomeric form with five pI variants (pI 5.5 to 6.3). It was found to be heat labile with complete inactivation up to 80°C and stable over a wide range of pH (4-11). The slow binding and competitive type of α-amylase inhibition was observed with 0.08μM of dissociation constant (Ki) for the enzyme-inhibitor complex (EI). The internal protein sequence of two subunits obtained by mass spectrometry matched with cereal-type α-AI, a conserved domain from AAI_LTSS superfamily and sialyltransferase-like protein respectively. In-vivo studies indicated up-regulation of total midgut α-amylase activity with negative effect on growth rate of H. armigera suggesting its suitability for pest control. PMID:26615146

  8. A nanostructured bifunctional Pd/C gas-diffusion electrode for metal-air batteries

    International Nuclear Information System (INIS)

    Graphical Abstract: Images showing (a) a scanning electrode microscope cross section of the Pd/C air electrode, (b) a TEM micrograph of the Pd/C catalyst, and (c) charge–discharge cycling of the air electrode in 6 mol dm−3 KOH at 20 mA cm−2 under 100 ml min−1 oxygen flow. - Highlights: • The Pd/C air electrode shows consistent good performance at modest current densities (20–80 mA cm−2), and is stable for 1000 cycles at room temperature. • The Pd/C air electrode has a potential difference of 0.53 V between oxygen evolution and oxygen reduction. • The air electrode makes efficient use of a small precious metal loading (0.5 mg cm−2), and is mainly made from lightweight carbon materials. • The air electrode has better stability than a commercial 2 mg cm−2 Pt/C electrode on repeated charge–discharge cycling, despite having a lower (and therefore less expensive) loading of catalyst. - Abstract: Designing a bifunctional air electrode which catalyses both the oxygen reduction and oxygen evolution reactions is an essential part of progress towards fully rechargeable metal-air batteries, such as the iron-air battery which is environmentally friendly, low cost, and does not suffer risk of thermal runaway like lithium-ion batteries. This paper reports the development of a lightweight carbon-based bifunctional air electrode, catalysed by a small (0.5 mg cm−2) loading of 30 wt.% palladium on carbon. The Pd-catalysed air electrode showed good bifunctional activity, with 0.53 V potential difference between oxygen reduction and evolution. The Pd/C air electrode showed improved catalytic activity at high current densities (≥ 50 mA cm−2) and enhanced durability compared with two commercial Pt/C air electrodes produced by Gaskatel GmbH and Johnson Matthey. A stable oxygen evolution potential was maintained over 1,000 charge-discharge cycles

  9. Oxygen electrode bifunctional electrocatalyst NiCo2O4 spinel

    Science.gov (United States)

    Fielder, William L.; Singer, Joseph

    1988-01-01

    A significant increase in energy density may be possible if a two-unit alkaline regenerative H2-O2 fuel cell is replaced with a single-unit system that uses passive means for H2O transfer and thermal control. For this single-unit system, new electrocatalysts for the O2 electrode will be required which are not only bifunctionally active but also chemically and electrochemically stable between the voltage range of about 0.7 and 1.5 V. NiCo2O4 spinel is reported to have certain characteristics that make it useful for a study of electrode fabrication techniques. High surface area NiCo2O4 powder was fabricated into unsupported, bifunctional, PTFE-bonded, porous gas fuel cell electrodes by commercial sources using varying PTFE contents and sintering temperatures. The object of this study is to measure the bifunctional activities of these electrodes and to observe what performance differences might result from different commercial electrode fabricators. O2 evolution and O2 reduction data were obtained at 80 C (31 percent KOH). An irreversible reaction (i.e., aging) occurred during O2 evolution at potentials greater than about 1.5 V. Anodic Tafel slopes of 0.06 and 0.12 V/decade were obtained for the aged electrodes. Within the range of 15 to 25 percent, the PTFE content was not a critical parameter for optimizing the electrode for O2 evolution activity. Sintering temperatures between 300 and 340 C may be adequate but heating at 275 C may not be sufficient to properly sinter the PTFE-NiCo2O4 mixture. Electrode disintegration was observed during O2 reduction. Transport of O2 to the NiCo2O4 surface became prohibitive at greater than about -0.02 A/sq cm. Cathodic Tafel slopes of -0.6 and -0.12 V/decade were assumed for the O2 reduction process. A PTFE content of 25 percent (or greater) appears to be preferable for sintering the PTFE-NiCo2O4 mixture.

  10. Extremal Infinite Graph Theory

    OpenAIRE

    Stein, Maya

    2011-01-01

    We survey various aspects of infinite extremal graph theory and prove several new results. The lead role play the parameters connectivity and degree. This includes the end degree. Many open problems are suggested.

  11. Extreme environments and exobiology

    Science.gov (United States)

    Friedmann, E. I.

    1993-01-01

    Ecological research on extreme environments can be applied to exobiological problems such as the question of life on Mars. If life forms (fossil or extant) are found on Mars, their study will help to solve fundamental questions about the nature of life on Earth. Extreme environments that are beyond the range of adaptability of their inhabitants are defined as "absolute extreme". Such environments can serve as terrestrial models for the last stages of life in the history of Mars, when the surface cooled down and atmosphere and water disappeared. The cryptoendolithic microbial community in porous rocks of the Ross Desert in Antarctica and the microbial mats at the bottom of frozen Antarctic lakes are such examples. The microbial communities of Siberian permafrost show that, in frozen but stable communities, long-term survival is possible. In the context of terraforming Mars, selected microorganisms isolated from absolute extreme environments are considered for use in creation of a biological carbon cycle.

  12. Hardware removal - extremity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007644.htm Hardware removal - extremity To use the sharing features on this page, please enable JavaScript. Surgeons use hardware such as pins, plates, or screws to help ...

  13. Estimating extreme flood probabilities

    International Nuclear Information System (INIS)

    Estimates of the exceedance probabilities of extreme floods are needed for the assessment of flood hazard at Department of Energy facilities. A new approach using a joint probability distribution of extreme rainfalls and antecedent soil moisture conditions, along with a rainfall runoff model, provides estimates of probabilities for floods approaching the probable maximum flood. This approach is illustrated for a 570 km2 catchment in Wisconsin and a 260 km2 catchment in Tennessee

  14. Upper Extremity Proprioceptive Training

    OpenAIRE

    Partin, Nina B.; Stone, Jennifer A; Ryan, Edward J.; Lueken, Joseph S.; Timm, Kent E.

    1994-01-01

    Proprioception following lower extremity injuries is commonly recommended, but there is little information on proprioception training following upper extremity injuries. No studies have evaluated whether proprioception programs for athletes in open kinetic chain activities (throwing, shot putting) should be different than programs for athletes in closed kinetic chain activities (gymnastics, swimming, kayaking, or rowing). In this paper, we provide a rationale for proprioception training for u...

  15. Averaged extreme regression quantile

    OpenAIRE

    Jureckova, Jana

    2015-01-01

    Various events in the nature, economics and in other areas force us to combine the study of extremes with regression and other methods. A useful tool for reducing the role of nuisance regression, while we are interested in the shape or tails of the basic distribution, is provided by the averaged regression quantile and namely by the average extreme regression quantile. Both are weighted means of regression quantile components, with weights depending on the regressors. Our primary interest is ...

  16. A Cascade-Reaction Nanoreactor Composed of a Bifunctional Molecularly Imprinted Polymer that Contains Pt Nanoparticles.

    Science.gov (United States)

    Wang, Jiao; Zhu, Maiyong; Shen, Xiaojuan; Li, Songjun

    2015-05-11

    This study was aimed at addressing the present challenge of cascade reactions, namely, how to furnish the catalysts with desired and hierarchical catalytic ability. This issue was addressed by constructing a cascade-reaction nanoreactor made of a bifunctional molecularly imprinted polymer containing acidic catalytic sites and Pt nanoparticles. The acidic catalytic sites within the imprinted polymer allowed one specified reaction, whereas the encapsulated Pt nanoparticles were responsible for another coupled reaction. To that end, the unique imprinted polymer was fabricated by using two well-coupled templates, that is, 4-nitrophenyl acetate and 4-nitrophenol. The catalytic hydrolysis of the former compound at the acidic catalytic sites led to the formation of the latter compound, which was further reduced by the encapsulated Pt nanoparticles to 4-aminophenol. Therefore, this nanoreactor demonstrated a catalytic-cascade ability. This protocol opens up the opportunity to develop functional catalysts for complicated chemical processes. PMID:25846700

  17. Bifunctional Nanoparticle-SILP Catalysts (NPs@SILP) for the Selective Deoxygenation of Biomass Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Luska, Kylie L. [RWTH Aachen Univ. (Germany); Julis, Jennifer [RWTH Aachen Univ. (Germany); Evonik Industries AG, Marl (Germany); Stavitski, Eli [Brookhaven National Lab. (BNL), Upton, NY (United States); Zakharov, Dmitri N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Adams, Alina [RWTH Aachen Univ. (Germany); Leitner, Walter [RWTH Aachen Univ. (Germany); Max Planck Inst. for Coal Research, Ruhr (Germany)

    2014-08-27

    We immobilized ruthenium nanoparticles onto an acidic supported ionic liquid phase (RuNPs@SILP) in the development of bifunctional catalysts for the selective deoxygenation of biomass substrates. RuNPs@SILPs possessed high catalytic activities, selectivities and recyclabilities in the hydrogenolytic deoxygenation and ring opening of C8- and C9-substrates derived from furfural or 5-hydroxymethylfurfural and acetone. When we tailor the acidity of the SILP through the ionic liquid loading provided a molecular parameter by which the catalytic activity and selectivity of the RuNPs@SILPs were controlled to provide a flexible catalyst system toward the formation of different classes of value-added products: cyclic ethers, primary alcohols or aliphatic ethers.

  18. Bifunctional hairy silica nanoparticles as high-performance additives for lubricant

    Science.gov (United States)

    Sui, Tianyi; Song, Baoyu; Wen, Yu-Ho; Zhang, Feng

    2016-03-01

    Bifunctional hairy silica nanoparticles (BHSNs), which are silica nanoparticles covered with alkyl and amino organic chains, were prepared as high-performance additives for lubricants. Compared with hairy silica nanoparticles covered by a single type of organic chain, binary hairy silica nanoparticles exhibit the advantages of both types of organic chains, which exhibit excellent compatibility with lubricants and adsorbability to metal surfaces. Nanoparticles with different ratios of amino and alkyl ligands were investigated. In comparison to an untreated lubricant, BHSNs reduce the friction coefficient and wear scar diameter by 40% and 60%, respectively. The wear mechanism of BHSNs was investigated, and the protective and filling effect of the nanoparticles improved because of collaboration of amino and alkyl ligands.

  19. Dyes as bifunctional markers of DNA hybridization on surfaces and mutation detection.

    Science.gov (United States)

    García-Mendiola, Tania; Cerro, María Ramos; López-Moreno, José María; Pariente, Félix; Lorenzo, Encarnación

    2016-10-01

    The interaction of small molecules with DNA has found diagnostic and therapeutic applications. In this work, we propose the use of two different dyes, in particular Azure A and Safranine, as bifunctional markers of on-surface DNA hybridization and potent tools for screening of specific gene mutations directly in real DNA PCR amplicons extracted from blood cells. By combining spectroscopic and electrochemical methods we demonstrate that both dyes can interact with single and double stranded DNA to a different extent, allowing reliable hybridization detection. From these data, we have also elucidated the nature of the interaction. We conclude that the binding mode is fundamentally intercalative with an electrostatic component. The dye fluorescence allows their use as nucleic acid stains for the detection of on-surfaces DNA hybridization. Its redox activity is exploited in the development of selective electrochemical DNA biosensors. PMID:27317997

  20. Synthesis and application of glycolic esters in methanol-gasoline as bifunctional additives

    International Nuclear Information System (INIS)

    To explore new and multifunctional additives for methanol-gasoline, glycolic esters were synthesized and screened as phase stabilizer and saturation vapor pressure depressor. The effect of the esters structure on the efficiency was discussed. It was found that the stability of the blends depend on the length of the glycolic esters' alkoxy group, and hexyl glycolic and octyl glycolic were found to be the most effective in various gasoline-methanol blends. Additionally, the glycolic esters can depress the saturation vapor pressure of methanol-gasoline effectively as well, and decyl glycolic is the most effective one. With these data, it can be concluded that the glycolic esters have the great potential to be used as bifunctional gasoline-methanol additives. (author)

  1. Novel 3-nitrotriazole-based amides and carbinols as bifunctional antichagasic agents.

    Science.gov (United States)

    Papadopoulou, Maria V; Bloomer, William D; Lepesheva, Galina I; Rosenzweig, Howard S; Kaiser, Marcel; Aguilera-Venegas, Benjamín; Wilkinson, Shane R; Chatelain, Eric; Ioset, Jean-Robert

    2015-02-12

    3-Nitro-1H-1,2,4-triazole-based amides with a linear, rigid core and 3-nitrotriazole-based fluconazole analogues were synthesized as dual functioning antitrypanosomal agents. Such compounds are excellent substrates for type I nitroreductase (NTR) located in the mitochondrion of trypanosomatids and, at the same time, act as inhibitors of the sterol 14α-demethylase (T. cruzi CYP51) enzyme. Because combination treatments against parasites are often superior to monotherapy, we believe that this emerging class of bifunctional compounds may introduce a new generation of antitrypanosomal drugs. In the present work, the synthesis and in vitro and in vivo evaluation of such compounds is discussed. PMID:25580906

  2. A Bifunctional Electrocatalyst for Oxygen Evolution and Oxygen Reduction Reactions in Water

    Science.gov (United States)

    Faschinger, Felix; Chattopadhyay, Samir; Bhakta, Snehadri; Mondal, Biswajit; Elemans, Johannes A. A. W.; Müllegger, Stefan; Tebi, Stefano; Koch, Reinhold; Klappenberger, Florian; Paszkiewicz, Mateusz; Barth, Johannes V.; Rauls, Eva; Aldahhak, Hazem; Schmidt, Wolf Gero

    2016-01-01

    Abstract Oxygen reduction and water oxidation are two key processes in fuel cell applications. The oxidation of water to dioxygen is a 4 H+/4 e− process, while oxygen can be fully reduced to water by a 4 e−/4 H+ process or partially reduced by fewer electrons to reactive oxygen species such as H2O2 and O2 −. We demonstrate that a novel manganese corrole complex behaves as a bifunctional catalyst for both the electrocatalytic generation of dioxygen as well as the reduction of dioxygen in aqueous media. Furthermore, our combined kinetic, spectroscopic, and electrochemical study of manganese corroles adsorbed on different electrode materials (down to a submolecular level) reveals mechanistic details of the oxygen evolution and reduction processes.

  3. Cage-like bifunctional chelators, copper-64 radiopharmaceuticals and PET imaging using the same

    Energy Technology Data Exchange (ETDEWEB)

    Conti, Peter S.; Cai, Hancheng; Li, Zibo; Liu, Shuanglong

    2016-08-02

    Disclosed is a class of versatile Sarcophagine based bifunctional chelators (BFCs) containing a hexa-aza cage for labeling with metals having either imaging, therapeutic or contrast applications radiolabeling and one or more linkers (A) and (B). The compounds have the general formula ##STR00001## where A is a functional group selected from group consisting of an amine, a carboxylic acid, an ester, a carbonyl, a thiol, an azide and an alkene, and B is a functional group selected from the group consisting of hydrogen, an amine, a carboxylic acid, and ester, a carbonyl, a thiol, an azide and an alkene. Also disclosed are conjugate of the BFC and a targeting moiety, which may be a peptide or antibody. Also disclosed are metal complexes of the BFC/targeting moiety conjugates that are useful as radiopharmaceuticals, imaging agents or contrast agents.

  4. Mono- and bi-functional arenethiols as surfactants for gold nanoparticles: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Fratoddi Ilaria

    2011-01-01

    Full Text Available Abstract Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis. The size, shape, and crystalline structure of the gold nanoparticles have been determined by high-resolution electron microscopy and full-pattern X-ray powder diffraction analyses. Nanocrystals diameters have been tuned in the range 2 ÷ 9 nm by a proper variation of Au/S molar ratio. The chemical composition of gold nanoparticles and their interaction with thiols have been investigated by X-ray photoelectron spectroscopy. In particular, the formation of networks has been observed with interconnected gold nanoparticles containing 1,4-benzenedimethanethiol as ligand.

  5. Bi-functional biobased packing of the cassava starch, glycerol, licuri nanocellulose and red propolis.

    Directory of Open Access Journals (Sweden)

    Samantha Serra Costa

    Full Text Available The aim of this study was to characterize and determine the bi-functional efficacy of active packaging films produced with starch (4% and glycerol (1.0%, reinforced with cellulose nanocrystals (0-1% and activated with alcoholic extracts of red propolis (0.4 to 1.0%. The cellulose nanocrystals used in this study were extracted from licuri leaves. The films were characterized using moisture, water-activity analyses and water vapor-permeability tests and were tested regarding their total phenolic compounds and mechanical properties. The antimicrobial and antioxidant efficacy of the films were evaluated by monitoring the use of the active films for packaging cheese curds and butter, respectively. The cellulose nanocrystals increased the mechanical strength of the films and reduced the water permeability and water activity. The active film had an antimicrobial effect on coagulase-positive staphylococci in cheese curds and reduced the oxidation of butter during storage.

  6. Bi-Functional Biobased Packing of the Cassava Starch, Glycerol, Licuri Nanocellulose and Red Propolis

    Science.gov (United States)

    Costa, Samantha Serra; Druzian, Janice Izabel; Machado, Bruna Aparecida Souza; de Souza, Carolina Oliveira; Guimarães, Alaíse Gil

    2014-01-01

    The aim of this study was to characterize and determine the bi-functional efficacy of active packaging films produced with starch (4%) and glycerol (1.0%), reinforced with cellulose nanocrystals (0–1%) and activated with alcoholic extracts of red propolis (0.4 to 1.0%). The cellulose nanocrystals used in this study were extracted from licuri leaves. The films were characterized using moisture, water-activity analyses and water vapor-permeability tests and were tested regarding their total phenolic compounds and mechanical properties. The antimicrobial and antioxidant efficacy of the films were evaluated by monitoring the use of the active films for packaging cheese curds and butter, respectively. The cellulose nanocrystals increased the mechanical strength of the films and reduced the water permeability and water activity. The active film had an antimicrobial effect on coagulase-positive staphylococci in cheese curds and reduced the oxidation of butter during storage. PMID:25383783

  7. A sustainable method inspired by nature for the production of original bi-functional nutraceuticals containing prebiotic fibers and highly bio-available forms of calcium and magnesium

    OpenAIRE

    Goffin, Dorothée; Blecker, Christophe; Paquot, Michel

    2012-01-01

    A sustainable method inspired by nature is proposed leading to an original bifunctional product active on gut health, metabolism regulation, immunity and mineral fortification, fighting against topical chronic diseases (type2 diabetes, osteoporosis, colon cancer…). Peer reviewed

  8. Chemical modification of multiwalled carbon nanotube with a bifunctional caged ligand for radioactive labelling

    International Nuclear Information System (INIS)

    Graphical abstract: The findings of this work describe a new method that can be utilised to radioactively label multiwalled carbon nanotube (MWCNT) powders with the use of a bi-functional cage ligand. -- Abstract: Carboxyl-functionalized multiwalled carbon nanotubes (MWCNTs) have been successfully radiolabelled with cobalt-57 (57Co) (T1/2 = 270 days) via the attachment of the bifunctional caged ligand MeAMN3S3sar. In this study MeAMN3S3sar has been synthesized and coupled to MWCNTs to form the conjugate MWCNT–MeAMN3S3sar. Synthesis was confirmed with nuclear magnetic resonance. X-ray photoelectron spectroscopy (XPS) confirmed the conjugation. Non-radioactive labelling of this conjugate was completed with Cu(II) ions to confirm the stability of the MeAMN3S3sar after coupling with the MWCNTs. The complexation of the Cu(II) was also confirmed with XPS. Transmission electron microscopy was used to demonstrate that the coupling reaction had a negligible effect on the size and shape of the MWCNTs. Radiolabelling of the MWCNT–MeAMN3S3sar conjugate and pristine (untreated) MWCNTs (non-specific) with the gamma-emitting radioactive isotope 57Co were compared. The radiolabelling efficiency of the MWCNT–MeAMN3S3sar conjugate was significantly higher (95% vs. 0.1%) (P ⩽ 0.001) than for the unconjugated pristine MWCNTs. This will allow for the potential tracking of nanoparticle movement in vitro and in vivo

  9. Cobalt Selenide Nanostructures: An Efficient Bifunctional Catalyst with High Current Density at Low Coverage.

    Science.gov (United States)

    Masud, Jahangir; Swesi, Abdurazag T; Liyanage, Wipula P R; Nath, Manashi

    2016-07-13

    Electrodeposited Co7Se8 nanostructures exhibiting flake-like morphology show bifunctional catalytic activity for oxygen evolution and hydrogen evolution reaction (OER and HER, respectively) in alkaline medium with long-term durability (>12 h) and high Faradaic efficiency (99.62%). In addition to low Tafel slope (32.6 mV per decade), the Co7Se8 OER electrocatalyst also exhibited very low overpotential to achieve 10 mA cm(-2) (0.26 V) which is lower than other transition metal chalcogenide based OER electrocatalysts reported in the literature and significantly lower than the state-of-the-art precious metal oxides. A low Tafel slope (59.1 mV per decade) was also obtained for the HER catalytic activity in alkaline electrolyte. The OER catalytic activity could be further improved by creating arrays of 3-dimensional rod-like and tubular structures of Co7Se8 through confined electrodeposition on lithographically patterned nanoelectrodes. Such arrays of patterned nanostructures produced exceptionally high mass activity and gravimetric current density (∼68 000 A g(-1)) compared to the planar thin films (∼220 A g(-1)). Such high mass activity of the catalysts underlines reduction in usage of the active material without compromising efficiency and their practical applicability. The catalyst layer could be electrodeposited on different substrates, and an effect of the substrate surface on the catalytic activity was also investigated. The Co7Se8 bifunctional catalyst enabled water electrolysis in alkaline solution at a cell voltage of 1.6 V. The electrodeposition works with exceptional reproducibility on any conducting substrate and shows unprecedented catalytic performance especially with the patterned growth of catalyst rods and tubes. PMID:27309595

  10. Gently reduced graphene oxide incorporated into cobalt oxalate rods as bifunctional oxygen electrocatalyst

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: Water-oxygen electrochemistry is at the heart of key renewable energy technologies (fuel cells, electrolyzers, and metal-air batteries) due to the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although much effort has been devoted to the development of improved bifunctional electrocatalysts, an inexpensive, highly active oxygen electrocatalyst, however, remains to be a challenge. In this paper, we present a facile and robust method to create gently reduced graphene oxide incorporated into cobalt oxalate microstructures (CoC2O4/gRGO) and demonstrate its excellent and stable electrocatalytic activity in both OER and ORR, arising from the inherent properties of the components and their physicochemical interaction. Our synthesis technique also explores a single pot method to partially reduce graphene oxide and form CoC2O4 structures while maintaining the solution processability of reduced graphene oxide. While the OER activity of CoC2O4/gRGO is exclusively due to CoC2O4, which transformed into OER-active Co species, the combination with gRGO significantly improves OER stability. On the other hand, CoC2O4/gRGO exhibits synergistic effect towards ORR, via a quasi-four-electron pathway, leading to a slightly higher ORR limiting current than Pt/C. Remarkably, gRGO offers dual functionality, contributing to ORR activity via the N-functional groups and also enhancing OER stability through the gRGO coating around CoC2O4 structures. Our results suggest a new class of metal-carbon composite that has the potential to be alternative bifunctional catalysts for regenerative fuel cells and metal-air batteries

  11. Evaluation of copper-labeled bifunctional chelate-albumin conjugates for blood pool imaging

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, C.J.; Rocque, P.A.; Welch, M.J. (Washington Univ., St. Louis, MO (United States). Edward Mallinckrodt Inst. of Radiology); Weinheimer, C.J. (Washington Univ., St. Louis, MO (United States). School of Medicine)

    1993-05-01

    [sup 62]Cu is a generator-produced positron-emitting radionuclide with a half-life amenable to blood-pool imaging with PET. Three bifunctional chelates [cyclic anhydride of diethylenetriamine-pentaacetic acid (cDTPAA), 6-bromoacetamidobenzyl-1,4,8,11-tetraazacyclotetradecane-N,N',N'', N''' tetraacetic acid (BAT), and p-carboxyethylphenylglyoxal-bis-([sup 4])N-methyl-thiosemicarbazone (CE-DTS)] were conjugated to HSA and labeled with [sup 67]Cu. Blood clearance and biodistribution of these three [sup 67]Cu-labeled conjugates were determined in rats. Of the three [sup 67]Cu-labeled bifunctional chelate-HSA conjugates, [sup 67]Cu-benzyl-TETA-HSA remained in the blood pool the longest, achieving stable blood levels at times longer than 24 h post-injection. The [sup 67]Cu radioactivity cleared the blood within 60 min post-injection of [sup 67]Cu-DTS-HSA, and within 10 min after administration of [sup 67]Cu-DTPA-HSA, indicating the dissociation of Cu[sup 2+] from these conjugates. Copper-labeled DTS-HSA achieved stable blood concentrations for at least 30 min post-injection and was therefore evaluated as a vascular imaging agent. DTS-HSA and benzy-TETA-HSA were labeled with [sup 62]Cu and administered to a dog for blood-pool imaging using PET. Because of the high labeling efficiency, DTS-HSA can be labeled with [sup 62]Cu without purification, making it more practical than [sup 62]Cu-benzyl-TETA-HSA as a blood-pool imaging agent. Generator-produced [sup 62]Cu-DTS-HSA should be a viable alternative blood pool agent to cyclotron-produced C[sup 15]O for PET facilities without cyclotrons. (author).

  12. Bifunctional Effect of Human IFN-γon Cultured Human Fibroblasts from Tenon's Capsule

    Institute of Scientific and Technical Information of China (English)

    Yan Guo; Jian Ge; Haiquan Liu; Yanyan Li; Jianliang Zheng; Xiangkun Huang; Yuqing Lan

    2000-01-01

    Purpose: To study the effect of human IFN-γ on in vitro cultured human fibroblasts from Tenon's capsuleMaterials and methods: The effect of different concentrations of human IFN-γ and mitomycin-C (MMC), 5-fluorouracil (5-Fu) on cultured human Tenon's capsule fibroblasts (HTCF) was measured using a MIT [3-(4, 5-dimethylthiazo-2-yl)] -2,5-diphenyltetrazolium bromide; Thiazolyl blue) colorimetric assay. The results were analyzed using ANOVA of the statistical package for social sciences (SPSS) 9.0version. The difference was considered to be significant if P < 0. 05.Results: The effects of MMC and 5-Fu on the growth of HTCF were negative, while the effects of IFN-γ on the growth of HTCF were both negative (102 ~ l04 units/ml in two experiments) and positive (106, 105, 10 units/ml in two experiments) . The inhibition rate of MMC ranged from 5.73% to 46. 9%, which was similar to the inhibition rate of 5-Fu ranged from 12.49% to 38.92% ( P= 0. 351) . The inhibition rate of IFN-γ in two experiments was smaller than MMC and 5-Fu ( P < 0.05).Conclusion: IFN-γ has bifunctional effect (both enhancement and inhibition) on proliferation of cultured HTCF. The antiproliferative effect of IFN-γ was weaker than MMC and 5-Fu. Further study has to be carried out to document the inhibition of scar formation of filtration bleb by IFN-γ and the molecular mechanisms of its bifunctional effect on HTCF proliferation. Eye Science 2000; 16: 43~ 47.

  13. Bifunctional Effect of Human IFN-γ on Cultured Human Fibroblasts from Tenon‘s Capsule

    Institute of Scientific and Technical Information of China (English)

    YanGuo; JianGe; 等

    2002-01-01

    Purpose:To study the effect of human IFN-γ on in ivtro cultured human fibroblasts from Tenon's capsule.Materials and methods:The effect of different concentrations of human IFN-γand mitomycin-C (MMC),5-fluorouracil(5-Fu) on cultured human Tenon's capsule fibroblasts(HTCF) was measured using a MTT[3-(4,5-dimethylthiazo-2-yI)]-2,5-diphenylterazolium bromide;Thiazolyl blue) colorimetric assay.The results were analyzed using ANOVA of the statistical package for social sciences (SPSS) 9.0 version.The difference was considered to be significant if P<0.05.Results:The effects of MMC and 5-Fu on the growth of HTCF were negative,while the effects of IFN-γon the growth of HTCF were both negative(102-104 units/ml in two experiments)and positive(106,105,10 units /ml in two experiments).The inhibition rate of MMC ranged from 5.73% to 46.9% ,which was similar to the inhibition rate of 5-Fu ranged from 12.49% to 38.92%(P=0.351).The inhibition rate of IFN-γ in two experiments was smaller than MMC and 5-Fu (P<0.05).Conclusion: IFN-γ has bifunctional effect (both enhancement and inhibition)on proliferation of cultured HTCF.The antiproliferative effect of IFN-γ was weaker than MMC and 5-Fu.Further study has to be carried out to document theinhibition of scar formation of filtration bleb by IFN-γ and the molecular mechanisms of its bifunctional effect on HTCF proliferation.Eye Science 2000;16:43-47.

  14. Extreme Programming: Maestro Style

    Science.gov (United States)

    Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang; Powell, Mark

    2009-01-01

    "Extreme Programming: Maestro Style" is the name of a computer programming methodology that has evolved as a custom version of a methodology, called extreme programming that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA's Jet Propulsion Laboratory that develops software for Mars exploration missions. Extreme programming is oriented toward agile development of software resting on values of simplicity, communication, testing, and aggressiveness. Extreme programming involves use of methods of rapidly building and disseminating institutional knowledge among members of a computer-programming team to give all the members a shared view that matches the view of the customers for whom the software system is to be developed. Extreme programming includes frequent planning by programmers in collaboration with customers, continually examining and rewriting code in striving for the simplest workable software designs, a system metaphor (basically, an abstraction of the system that provides easy-to-remember software-naming conventions and insight into the architecture of the system), programmers working in pairs, adherence to a set of coding standards, collaboration of customers and programmers, frequent verbal communication, frequent releases of software in small increments of development, repeated testing of the developmental software by both programmers and customers, and continuous interaction between the team and the customers. The environment in which the Maestro team works requires the team to quickly adapt to changing needs of its customers. In addition, the team cannot afford to accept unnecessary development risk. Extreme programming enables the Maestro team to remain agile and provide high-quality software and service to its customers. However, several factors in the Maestro environment have made it necessary to modify some of the conventional extreme

  15. Winter Storms and Extreme Cold

    Science.gov (United States)

    ... Tornadoes Tsunamis Volcanoes Wildfires Main Content Snowstorms & Extreme Cold This page explains what actions to take when ... snowstorm or extreme cold. Before Snowstorms and Extreme Cold To prepare for a winter storm you should ...

  16. Extreme meteorological conditions

    International Nuclear Information System (INIS)

    Different meteorological variables which may reach significant extreme values, such as the windspeed and, in particular, its occurrence through tornadoes and hurricanes that necesarily incide and wich must be taken into account at the time of nuclear power plants' installation, are analyzed. For this kind of study, it is necessary to determine the basic phenomenum of design. Two criteria are applied to define the basic values of design for extreme meteorological variables. The first one determines the expected extreme value: it is obtained from analyzing the recurence of the phenomenum in a convened period of time, wich may be generally of 50 years. The second one determines the extreme value of low probability, taking into account the nuclear power plant's operating life -f.ex. 25 years- and considering, during said lapse, the occurrence probabilities of extreme meteorological phenomena. The values may be determined either by the deterministic method, which is based on the acknowledgement of the fundamental physical characteristics of the phenomena or by the probabilistic method, that aims to the analysis of historical statistical data. Brief comments are made on the subject in relation to the Argentine Republic area. (R.J.S.)

  17. Imaging cancer using PET - the effect of the bifunctional chelator on the biodistribution of a {sup 64}Cu-labeled antibody

    Energy Technology Data Exchange (ETDEWEB)

    Dearling, Jason L.J., E-mail: jason.dearling@childrens.harvard.ed [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Voss, Stephan D. [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Dunning, Patricia; Snay, Erin [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Fahey, Frederic [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Smith, Suzanne V. [Australian National Science and Technology Organisation (ANSTO), New Illawarra Road, PMB1, Menai, New South Wales 2234 (Australia); Huston, James S. [EMD Serono Research Center, 45A Middlesex Turnpike, Billerica, MA 01821-3936 (United States); Boston Biomedical Research Institute, Watertown, MA 02472-2899 (United States); Meares, Claude F. [Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616-5295 (United States); Treves, S. Ted; Packard, Alan B. [Division of Nuclear Medicine and Department of Radiology, Children' s Hospital Boston, 300 Longwood Avenue, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States)

    2011-01-15

    Introduction: Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the {sup 64}Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with {sup 64}Cu using these chelators in tumor-bearing mice. Methods: The chelators [S-2-(aminobenzyl)1,4,7-triazacyclononane-1,4,7-triacetic acid (p-NH{sub 2}-Bn-NOTA): 6-[p-(bromoacetamido)benzyl]-1, 4, 8, 11-tetraazacyclotetradecane-N, N', N'', N'''-tetraacetic acid (BAT-6): S-2-(4-aminobenzyl)-1,4,7,10-tetraazacyclododocane tetraacetic acid (p-NH{sub 2}-Bn-DOTA): 1,4,7,10-tetraazacyclododocane-N, N', N', N''-tetraacetic acid (DOTA): and 1-N-(4-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1, 8-diamine (SarAr)] were conjugated to the anti-GD2 antibody ch14.18, and the modified antibody was labeled with {sup 64}Cu and injected into mice bearing subcutaneous human melanoma tumors (M21) (n = 3-5 for each study). Biodistribution data were obtained from positron emission tomography images acquired at 1, 24 and 48 hours post-injection, and at 48 hours post-injection a full ex vivo biodistribution study was carried out. Results: The biodistribution, including tumor targeting, was similar for all the radioimmunoconjugates. At 48 h post-injection, the only statistically significant differences in radionuclide uptake (p < 0.05) were between blood, liver, spleen and kidney. For example, liver uptake of [{sup 64}Cu]ch14.18-p-NH{sub 2}-Bn-NOTA was 4.74 {+-} 0.77 per cent of the injected dose per gram of tissue (%ID/g), and for [{sup 64}Cu]ch14.18-SarAr was 8.06 {+-} 0.77 %ID/g. Differences in tumor targeting correlated with variations in tumor size rather than which BFC was used. Conclusions: The results of this

  18. Cloning and analysis of a bifunctional methyltransferase/restriction endonuclease TspGWI, the prototype of a Thermus sp. enzyme family

    Directory of Open Access Journals (Sweden)

    Zylicz-Stachula Agnieszka

    2009-05-01

    Full Text Available Abstract Background Restriction-modification systems are a diverse class of enzymes. They are classified into four major types: I, II, III and IV. We have previously proposed the existence of a Thermus sp. enzyme family, which belongs to type II restriction endonucleases (REases, however, it features also some characteristics of types I and III. Members include related thermophilic endonucleases: TspGWI, TaqII, TspDTI, and Tth111II. Results Here we describe cloning, mutagenesis and analysis of the prototype TspGWI enzyme that recognises the 5'-ACGGA-3' site and cleaves 11/9 nt downstream. We cloned, expressed, and mutagenised the tspgwi gene and investigated the properties of its product, the bifunctional TspGWI restriction/modification enzyme. Since TspGWI does not cleave DNA completely, a cloning method was devised, based on amino acid sequencing of internal proteolytic fragments. The deduced amino acid sequence of the enzyme shares significant sequence similarity with another representative of the Thermus sp. family – TaqII. Interestingly, these enzymes recognise similar, yet different sequences in the DNA. Both enzymes cleave DNA at the same distance, but differ in their ability to cleave single sites and in the requirement of S-adenosylmethionine as an allosteric activator for cleavage. Both the restriction endonuclease (REase and methyltransferase (MTase activities of wild type (wt TspGWI (either recombinant or isolated from Thermus sp. are dependent on the presence of divalent cations. Conclusion TspGWI is a bifunctional protein comprising a tandem arrangement of Type I-like domains; particularly noticeable is the central HsdM-like module comprising a helical domain and a highly conserved S-adenosylmethionine-binding/catalytic MTase domain, containing DPAVGTG and NPPY motifs. TspGWI also possesses an N-terminal PD-(D/EXK nuclease domain related to the corresponding domains in HsdR subunits, but lacks the ATP-dependent translocase module

  19. Extremal dependence: some contributions

    CERN Document Server

    Ferreira, Helena

    2011-01-01

    Due to globalization and relaxed market regulation, we have assisted to an increasing of extremal dependence in international markets. As a consequence, several measures of tail dependence have been stated in literature in recent years, based on multivariate extreme-value theory. In this paper we present a tail dependence function and an extremal coefficient of dependence between two random vectors that extend existing ones. We shall see that in weakening the usual required dependence allows to assess the amount of dependence in $d$-variate random vectors based on bidimensional techniques. Very simple estimators will be stated and can be applied to the well-known \\emph{stable tail dependence function}. Asymptotic normality and strong consistency will be derived too. An application to financial markets will be presented at the end.

  20. Extremely deformable structures

    CERN Document Server

    2015-01-01

    Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...

  1. Statistics of Extremes

    KAUST Repository

    Davison, Anthony C.

    2015-04-10

    Statistics of extremes concerns inference for rare events. Often the events have never yet been observed, and their probabilities must therefore be estimated by extrapolation of tail models fitted to available data. Because data concerning the event of interest may be very limited, efficient methods of inference play an important role. This article reviews this domain, emphasizing current research topics. We first sketch the classical theory of extremes for maxima and threshold exceedances of stationary series. We then review multivariate theory, distinguishing asymptotic independence and dependence models, followed by a description of models for spatial and spatiotemporal extreme events. Finally, we discuss inference and describe two applications. Animations illustrate some of the main ideas. © 2015 by Annual Reviews. All rights reserved.

  2. Arabidopsis WUSCHEL is a bifunctional transcription factor that acts as a repressor in stem cell regulation and as an activator in floral patterning.

    Science.gov (United States)

    Ikeda, Miho; Mitsuda, Nobutaka; Ohme-Takagi, Masaru

    2009-11-01

    Most transcription factors act either as activators or repressors, and no such factors with dual function have been unequivocally identified and characterized in plants. We demonstrate here that the Arabidopsis thaliana protein WUSCHEL (WUS), which regulates the maintenance of stem cell populations in shoot meristems, is a bifunctional transcription factor that acts mainly as a repressor but becomes an activator when involved in the regulation of the AGAMOUS (AG) gene. We show that the WUS box, which is conserved among WOX genes, is the domain that is essential for all the activities of WUS, namely, for regulation of stem cell identity and size of floral meristem. All the known activities of WUS were eliminated by mutation of the WUS box, including the ability of WUS to induce the expression of AG. The mutation of the WUS box was complemented by fusion of an exogenous repression domain, with resultant induction of somatic embryogenesis in roots and expansion of floral meristems as observed upon ectopic expression of WUS. By contrast, fusion of an exogenous activation domain did not result in expanded floral meristems but induced flowers similar to those induced by the ectopic expression of AG. Our results demonstrate that WUS acts mainly as a repressor and that its function changes from that of a repressor to that of an activator in the case of regulation of the expression of AG. PMID:19897670

  3. Bifunctional quaternary ammonium compounds to inhibit biofilm growth and enhance performance for activated carbon air-cathode in microbial fuel cells

    Science.gov (United States)

    Li, Nan; Liu, Yinan; An, Jingkun; Feng, Cuijuan; Wang, Xin

    2014-12-01

    The slow diffusion of hydroxyl out of the catalyst layer as well as the biofouling on the surface of cathode are two problems affecting power for membrane-less air-cathode microbial fuel cells (MFCs). In order to solve both of them simultaneously, here we simply modify activated carbon air-cathode using a bifunctional quaternary ammonium compound (QAC) by forced evaporation. The maximum power density reaches 1041 ± 12 mW m-2 in an unbuffered medium (0.5 g L-1 NaCl), which is 17% higher than the control, probably due to the accelerated anion transport in the catalyst layer. After 2 months, the protein content reduced by a factor of 26 and the power density increases by 33%, indicating that the QAC modification can effectively inhibit the growth of cathodic biofilm and improve the stability of performance. The addition of NaOH and QAC epoxy have a negative effect on power production due to the clogging of pores in catalyst layer.

  4. Extremal graph theory

    CERN Document Server

    Bollobas, Bela

    2004-01-01

    The ever-expanding field of extremal graph theory encompasses a diverse array of problem-solving methods, including applications to economics, computer science, and optimization theory. This volume, based on a series of lectures delivered to graduate students at the University of Cambridge, presents a concise yet comprehensive treatment of extremal graph theory.Unlike most graph theory treatises, this text features complete proofs for almost all of its results. Further insights into theory are provided by the numerous exercises of varying degrees of difficulty that accompany each chapter. A

  5. Extreme Downside Liquidity Risk

    OpenAIRE

    Ruenzi, Stefan; Ungeheuer, Michael; Weigert, Florian

    2013-01-01

    We merge the literature on downside return risk with that on systematic liquidity risk and introduce the concept of extreme downside liquidity (EDL) risk. We show that the cross-section of expected stock returns reflects a premium for EDL risk. Strong EDL risk stocks deliver a positive risk premium of more than 4% p.a. as compared to weak EDL risk stocks. The effect is more pronounced after the market crash of 1987. It is not driven by linear liquidity risk or by extreme downside return risk,...

  6. Functionalization of nanoparticle titanium dioxide with different bifunctional organic molecules and trimers of transition compounds for obtaining new materials

    International Nuclear Information System (INIS)

    Functionalization of titanium dioxide in nanoporous anatase phase is investigated for obtaining new nanomaterials. Functionalizations were performed using two heating methods: the conventional of refluxing heating method and microwave irradiation with bifunctional organic molecules is used to study how to anchor molecules and the change in the wettability of the material. Besides, reactions with organic molecules were performed as the derived from nanoproxene. The growth layer by layer is performed using the bifunctional molecules previous for the immobilization of cobalt trimers. Functionalized molecules were characterized by infrared spectroscopy, X-ray diffraction, contact angle, scanning electron microscopy, x-ray elemental analysis, plasma atomic emission spectroscopy coupled inductively, x-ray photoelectron spectroscopy and thermogravimetric analysis. This type of functionalizations on nanoporous titanium dioxide could potentially improve optical sensitivity and activity of this nanomaterial in the visible region. (author)

  7. Purification, crystallization and preliminary X-ray crystallographic analysis of rice bifunctional α-amylase/subtilisin inhibitor from Oryza sativa

    International Nuclear Information System (INIS)

    The crystallization of rice α-amylase/subtilisin bifunctional inhibitor is reported. Rice bifunctional α-amylase/subtilisin inhibitor (RASI) can inhibit both α-amylase from larvae of the red flour beetle (Tribolium castaneum) and subtilisin from Bacillus subtilis. The synthesis of RASI is up-regulated during the late milky stage in developing seeds. The 8.9 kDa molecular-weight RASI from rice has been crystallized using the hanging-drop vapour-diffusion method. According to 1.81 Å resolution X-ray diffraction data from rice RASI crystals, the crystal belongs to space group P21212, with unit-cell parameters a = 79.99, b = 62.95, c = 66.70 Å. Preliminary analysis indicates two RASI molecules in an asymmetric unit with a solvent content of 44%

  8. Dual-Doped Molybdenum Trioxide Nanowires: A Bifunctional Anode for Fiber-Shaped Asymmetric Supercapacitors and Microbial Fuel Cells.

    Science.gov (United States)

    Yu, Minghao; Cheng, Xinyu; Zeng, Yinxiang; Wang, Zilong; Tong, Yexiang; Lu, Xihong; Yang, Shihe

    2016-06-01

    A novel in situ N and low-valence-state Mo dual doping strategy was employed to significantly improve the conductivity, active-site accessibility, and electrochemical stability of MoO3 , drastically boosting its electrochemical properties. Consequently, our optimized N-MoO3-x nanowires exhibited exceptional performances as a bifunctional anode material for both fiber-shaped asymmetric supercapacitors (ASCs) and microbial fuel cells (MFCs). The flexible fiber-shaped ASC and MFC device based on the N-MoO3-x anode could deliver an unprecedentedly high energy density of 2.29 mWh cm(-3) and a remarkable power density of 0.76 μW cm(-1) , respectively. Such a bifunctional fiber-shaped N-MoO3-x electrode opens the way to integrate the electricity generation and storage for self-powered sources. PMID:27097987

  9. Self-organization of Au–CdSe hybrid nanoflowers at different length scales via bi-functional diamine linkers

    International Nuclear Information System (INIS)

    This work introduces a series of molecular bridging bi-functional linkers to produce laterally self-assembled nanostructures of the Au–CdSe nanoflowers on different length scales ranging from 10 nm to 100 microns. Assembly of Au nanocrystals within amorphous CdSe rods is found in the early stages of the growth of the Au–CdSe nanoflowers. The Au–CdSe nanoflowers are formed through a one-pot low temperature (150 °C) process where CdSe clusters are adsorbed on the surface of the Au cores, and they then start to form multiple arms and branches resulting in flower-shaped hybrid nanostructures. More complex assembly at a micron length scale can be achieved by means of bi-functional capping agents with appropriate alkyl chain lengths, such as 1,12-diaminododecane.

  10. Dynamics of tropomyosin in muscle fibers as monitored by saturation transfer EPR of bi-functional probe.

    Directory of Open Access Journals (Sweden)

    Roni F Rayes

    Full Text Available The dynamics of four regions of tropomyosin was assessed using saturation transfer electron paramagnetic resonance in the muscle fiber. In order to fully immobilize the spin probe on the surface of tropomyosin, a bi-functional spin label was attached to i,i+4 positions via cysteine mutagenesis. The dynamics of bi-functionally labeled tropomyosin mutants decreased by three orders of magnitude when reconstituted into "ghost muscle fibers". The rates of motion varied along the length of tropomyosin with the C-terminus position 268/272 being one order of magnitude slower then N-terminal domain or the center of the molecule. Introduction of troponin decreases the dynamics of all four sites in the muscle fiber, but there was no significant effect upon addition of calcium or myosin subfragment-1.

  11. Synthesis and Characterization of Bifunctional Organic-Glasses Based on Diphenylhydrazone and Barbituric Acid Derivative for Photorefractive Application

    International Nuclear Information System (INIS)

    A series of amorphous molecules that possess both photoconductive and electro-optic properties was synthesized in order to investigate photorefractive properties of bifunctional organic-glasses. Diethylaminobenzaldehyde- diphenylhydrazone was covalently attached to 5-(4-diethylamino-benzylidene)-1,3-dimethylpyrimidine- 2,4,6-trione through a flexible alkyl chain (3, 4, 5, 6 and 10 carbons) containing two ether linkages. The longer linkage not only lowered the glass transition temperature (Tg) of the molecules, but also allowed faster orientation of the chromophore. To examine the photorefractive properties, a 50 μm-thick film was prepared from the mixture of a bifunctional molecule, butyl benzyl phthalate, and C60. The photoconductivity of this composite was as high as 8.01 x 10-12 S/cm at 60 V/μm, and the maximum diffraction efficiency (ηmax) of 50 μm-thick film was about 5% at 80 V/μm

  12. Crystallization and preliminary X-ray analysis of a bifunctional catalase-phenol oxidase from Scytalidium thermophilum

    International Nuclear Information System (INIS)

    The bifunctional enzyme catalase-phenol oxidase from S. thermophilum was crystallized by the hanging-drop vapour-diffusion method in space group P21 and diffraction data were collected to 2.8 Å resolution. Catalase-phenol oxidase from Scytalidium thermophilum is a bifunctional enzyme: its major activity is the catalase-mediated decomposition of hydrogen peroxide, but it also catalyzes phenol oxidation. To understand the structural basis of this dual functionality, the enzyme, which has been shown to be a tetramer in solution, has been purified by anion-exchange and gel-filtration chromatography and has been crystallized using the hanging-drop vapour-diffusion technique. Streak-seeding was used to obtain larger crystals suitable for X-ray analysis. Diffraction data were collected to 2.8 Å resolution at the Daresbury Synchrotron Radiation Source. The crystals belonged to space group P21 and contained one tetramer per asymmetric unit

  13. Self-organization of Au–CdSe hybrid nanoflowers at different length scales via bi-functional diamine linkers

    Energy Technology Data Exchange (ETDEWEB)

    AbouZeid, Khaled Mohamed [Virginia Commonwealth University, Department of Chemistry (United States); Mohamed, Mona Bakr [Cairo University, National Institute of Laser Enhanced Science (NILES) (Egypt); El-Shall, M. Samy, E-mail: mselshal@vcu.edu [Virginia Commonwealth University, Department of Chemistry (United States)

    2016-01-15

    This work introduces a series of molecular bridging bi-functional linkers to produce laterally self-assembled nanostructures of the Au–CdSe nanoflowers on different length scales ranging from 10 nm to 100 microns. Assembly of Au nanocrystals within amorphous CdSe rods is found in the early stages of the growth of the Au–CdSe nanoflowers. The Au–CdSe nanoflowers are formed through a one-pot low temperature (150 °C) process where CdSe clusters are adsorbed on the surface of the Au cores, and they then start to form multiple arms and branches resulting in flower-shaped hybrid nanostructures. More complex assembly at a micron length scale can be achieved by means of bi-functional capping agents with appropriate alkyl chain lengths, such as 1,12-diaminododecane.

  14. N,P-Codoped Carbon Networks as Efficient Metal-free Bifunctional Catalysts for Oxygen Reduction and Hydrogen Evolution Reactions.

    Science.gov (United States)

    Zhang, Jintao; Qu, Liangti; Shi, Gaoquan; Liu, Jiangyong; Chen, Jianfeng; Dai, Liming

    2016-02-01

    The high cost and scarcity of noble metal catalysts, such as Pt, have hindered the hydrogen production from electrochemical water splitting, the oxygen reduction in fuel cells and batteries. Herein, we developed a simple template-free approach to three-dimensional porous carbon networks codoped with nitrogen and phosphorus by pyrolysis of a supermolecular aggregate of self-assembled melamine, phytic acid, and graphene oxide (MPSA/GO). The pyrolyzed MPSA/GO acted as the first metal-free bifunctional catalyst with high activities for both oxygen reduction and hydrogen evolution. Zn-air batteries with the pyrolyzed MPSA/GO air electrode showed a high peak power density (310 W g(-1) ) and an excellent durability. Thus, the pyrolyzed MPSA/GO is a promising bifunctional catalyst for renewable energy technologies, particularly regenerative fuel cells. PMID:26709954

  15. Hydrocarbon fuel synthesis from sorbitol over bifunctional catalysts: Association of tungstated titania with platinum, palladium or iridium

    OpenAIRE

    Vilcocq, Léa; Cabiac, Amandine; Especel, Catherine; Lacombe, Sylvie; Duprez, Daniel

    2015-01-01

    To selectively transform sorbitol into hydrocarbons in aqueous phase, new bifunctional catalytic systems are designed by associating a hydrogenating metallic catalyst (M/ZrO2, M = Pt, Ir or Pd) and a dehydratingacidic catalyst (TiO2–WOx) in a mechanical mixture. Zirconium oxide was chosen as support because ithas virtually no dehydration activity and gives a good stability to the metal in water. This stability isevaluated through several characterizations before and after contact with the aqu...

  16. The bifunctional dihydrofolate reductase thymidylate synthase of Tetrahymena thermophila provides a tool for molecular and biotechnology applications

    OpenAIRE

    Tiedtke Arno; Bockau Ulrike; Herrmann Lutz; Hartmann Marcus WW; Weide Thomas

    2006-01-01

    Abstract Background Dihydrofolate reductase (DHFR) and thymidylate synthase (TS) are crucial enzymes in DNA synthesis. In alveolata both enzymes are expressed as one bifunctional enzyme. Results Loss of this essential enzyme activities after successful allelic assortment of knock out alleles yields an auxotrophic marker in ciliates. Here the cloning, characterisation and functional analysis of Tetrahymena thermophila's DHFR-TS is presented. A first aspect of the presented work relates to dest...

  17. Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis

    Science.gov (United States)

    Yu, Yu; Li, Pei; Wang, Xiaofang; Gao, Wenyu; Shen, Zongxu; Zhu, Yanan; Yang, Shuliang; Song, Weiguo; Ding, Kejian

    2016-05-01

    Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm-2 for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm-2 with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity. Electronic supplementary information (ESI) available: More SEM, TEM images, XRD patterns, LSV curves, XPS spectra. See DOI: 10.1039/c6nr02395a

  18. Enhanced bifunctional activity of LaNiO3-based gas diffusion electrodes for regenerative fuel cells

    OpenAIRE

    Silva, R A; Soares, C. O.; Carvalho, M. D.; C. M. Rangel; Pereira, M. I. da Silva

    2013-01-01

    Perovskites are of great interest when searching replacements for precious metals as catalyst for bifunctional oxygen electrodes involving the oxygen evolution(OER) and oxygen reduction reaction (ORR) as is the case of regenerative fuel cells. In this work a full electrochemical study on the electrochemical properties of gas diffusion electrodes (GDEs) using LaNiO3-based catalysts, conducted in alkaline media, led to a study of cyclability and durability. The incorporation of GDEs in a low po...

  19. Morphology-controlled growth of magnetic iron oxide components on gold nanoparticles as bi-functional agents

    OpenAIRE

    Li, L.; Leung, CW; Ruotolo, A.; Jiang, C; Pong, PWT

    2015-01-01

    Summary form only given. Hybrid nanostructure can inherit the physiochemical properties of its individual components to realize its multi-functionality. The coupling of plasmonic effect of gold nanoparticles with magnetic properties of iron oxide nanoparticles has shown great promise as bi-functional agents allowing simultaneous magnetic resonance imaging (MRI)/computed tomography (CT) imaging and magnetic/photonic thermal therapy. However, since gold and iron oxide are two dissimilar materia...

  20. The Role of the Methyltransferase Domain of Bifunctional Restriction Enzyme RM.BpuSI in Cleavage Activity

    OpenAIRE

    Arthur Sarrade-Loucheur; Shuang-yong Xu; Siu-Hong Chan

    2013-01-01

    Restriction enzyme (REase) RM.BpuSI can be described as a Type IIS/C/G REase for its cleavage site outside of the recognition sequence (Type IIS), bifunctional polypeptide possessing both methyltransferase (MTase) and endonuclease activities (Type IIC) and endonuclease activity stimulated by S-adenosyl-L-methionine (SAM) (Type IIG). The stimulatory effect of SAM on cleavage activity presents a major paradox: a co-factor of the MTase activity that renders the substrate unsusceptible to cleavag...

  1. L-Threonine-derived novel bifunctional phosphine-sulfonamide catalyst-promoted enantioselective aza-morita-Baylis-Hillman reaction

    KAUST Repository

    Zhong, Fangrui

    2011-03-18

    A series of novel bifunctional phosphine-sulfonamide organic catalysts were designed and readily prepared from natural amino acids, and they were utilized to promote enantioselective aza-Morita-Baylis-Hillman (MBH) reactions. l-Threonine-derived phosphine-sulfonamide 9b was found to be the most efficient catalyst, affording the desired aza-MBH adducts in high yields and with excellent enantioselectivities. © 2011 American Chemical Society.

  2. Discourse of gender extremism

    Directory of Open Access Journals (Sweden)

    Butaeva M. A.

    2010-06-01

    Full Text Available The phenomenon of a gender discourse, being interdisciplinary on the base properties, interests also representatives of social philosophy, sociology, social psychology, cultural science, economic and legal sciences. In a gender discourse it is possible to allocate masculinistic and feministic currents. These organizations are bright representatives of gender extremism.

  3. Statistics of Local Extremes

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Bierbooms, W.; Hansen, Kurt Schaldemose

    2003-01-01

    theoretical expression for the probability density function associated with local extremes of a stochasticprocess is presented. The expression is basically based on the lower four statistical moments and a bandwidth parameter. The theoretical expression is subsequently verified by comparison with simulated...

  4. EXTREME LEARNING MACHINE

    OpenAIRE

    Rudranshu Sharma; Ankur Singh Bist*; vikas sharma

    2015-01-01

    Machine learning [1], a branch of artificial intelligence, that gives computers the ability to learn without being explicitly programmed, means it gives system the ability to learn from data. There are two types of learning techniques: supervised learning and unsupervised learning [2]. In this paper, we describe what Extreme Learning Machine is, their advantages and limitations followed by a study of genetic algorithm.

  5. Optimization using Extremal Dynamics

    Science.gov (United States)

    Boettcher, Stefan

    2001-03-01

    We explore a new heuristic for finding high-quality solutions to NP-hard optimization problems which we have recently introduced [see ``Nature's Way of Optimizing," Artificial Intelligence 119, 275-286 (2000) and cond-mat/0010337]. The method, called extremal optimization, is inspired by self-organized criticality, a concept introduced to describe emergent complexity in physical systems. Extremal optimization successively replaces extremely undesirable elements of a single sub-optimal solution with new, random ones. Large fluctuations ensue that efficiently explore many local optima. With only one adjustable parameter, its performance has proved competitive with more elaborate methods, especially near phase transitions which are believed to contain the hardest instances. In particular, extremal optimization is superior to simulated annealing in the partitioning of sparse graphs, it finds the overlap of all ground-states at the phase transition of the 3-coloring problem, and it provides independent confirmation for the ground-state energy of spin glasses, previously obtained with elaborate genetic algorithms.

  6. Discourse of gender extremism

    OpenAIRE

    Butaeva M. A.

    2010-01-01

    The phenomenon of a gender discourse, being interdisciplinary on the base properties, interests also representatives of social philosophy, sociology, social psychology, cultural science, economic and legal sciences. In a gender discourse it is possible to allocate masculinistic and feministic currents. These organizations are bright representatives of gender extremism.

  7. Climate Extremes and Society

    Science.gov (United States)

    Mote, Philip

    2009-10-01

    In October 2005, as the United States still was reeling from Hurricane Katrina in August and as the alphabet was too short to contain all of that year's named Atlantic tropical storms (Hurricane Wilma was forming near Jamaica), a timely workshop in Bermuda focused on climate extremes and society (see Eos, 87(3), 25, 17 January 2006). This edited volume, which corresponds roughly to the presentations given at that workshop, offers a fascinating look at the critically important intersection of acute climate stress and human vulnerabilities. A changing climate affects humans and other living things not through the variable that most robustly demonstrates the role of rising greenhouse gases—globally averaged temperature—but through local changes, especially changes in extremes. The first part of this book, “Defining and modeling the nature of weather and climate extremes,” focuses on natural science. The second part, “Impacts of weather and climate extremes,” focuses on societal impacts and responses, emphasizing an insurance industry perspective because a primary sponsor of the workshop was the Risk Prediction Initiative, whose aim is to “support scientific research on topics of interest to its sponsors” (p. 320).

  8. Bifunctional chimeric SuperCD suicide gene -YCD: YUPRT fusion is highly effective in a rat hepatoma model

    Institute of Scientific and Technical Information of China (English)

    Florian Graepler; Ulrike A Lauer; Reinhard Vonthein; Michael Gregor; Sorin Armeanu; Michael Bitzer; Ulrich M. Lauer; Marie-Luise Lemken; Wolfgang A Wybranietz; Ulrike Schmidt; Irina Smirnow; Christine D Groβ; Martin Spiegel; Andrea Schenk; Hansj(o)rg Graf

    2005-01-01

    AIM: To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model.METHODS: To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine (5-FC), we generated a chimeric bifunctional SuperCD suicide gene, a fusion of the yeast cytosine deaminase (YCD) and the yeast uracil phosphoribosyltransferase (YUPRT) gene.RESULTS: In vitro stably transduced Morris rat hepatoma cells (MH) expressing the bifunctional SuperCD suicide gene (MH SuperCD) showed a clearly marked enhancement in cell killing when incubated with 5-FC as compared with MH ceils stably expressing YCD solely (MH YCD) or the cytosine deaminase gene of bacterial origin(MH BCD), respectively. In vivo, MH SuperCD tumors implanted both subcutaneously as well as orthotopically into the livers of syngeneic ACI rats demonstrated significant tumor regressions (P<0.01) under both high dose as well as low dose systemic 5-FC application,whereas MH tumors without transgene expression (MH naive) showed rapid progression. For the first time, an order of in vivo suicide gene effectiveness (SuperCD>>YCD > > BCD > > > negative control) was defi ned as a result of a directin vivo comparison of all three suicide genes.CONCLUSION: Bifunctional SuperCD suicide gene expression is highly effective in a rat hepatoma model,thereby significantly improving both the therapeutic index and the efficacy of hepatocellular carcinoma killing by fluorocytosine.

  9. Gold nanoparticle immobilization on ZnO nanorods via bi-functional monolayers: A facile method to tune interface properties

    Science.gov (United States)

    Jayaraman, Sundaramurthy; Suresh Kumar, P.; Mangalaraj, D.; Dharmarajan, Rajarathnam; Ramakrishna, Seeram; P Srinivasan, M.

    2015-11-01

    We demonstrated the functionalization of one dimensional (1-D) zinc oxide nanorods (ZnO NRs) using bi-functional organic molecules to create hybrid structures with surface functionalities and tuneable organic/inorganic interface. Bi-functional molecules with carboxylic acid, thiol and silane end groups and amine termination had been employed to functionalize the NRs by forming carboxylate, thiolate and hydroxylation bonds, respectively, with ZnO. The surface textures of NRs were preserved even after functionalization. The functionalized NRs were decorated with gold nanoparticles (AuNPs) and the hybrid structures exhibited a quenched blue shift ultraviolet emission which depended on the distance between the ZnO surface and the AuNPs. The NR functionalization with bi-functional molecules and decoration of NPs, and surface morphologies were analyzed using x-ray photoelectron spectroscopy, field emission scanning electron microscopy and transmission electron spectroscopy. These hybrid structures can play a vital role in tuning the interface properties and have potential applications in future photovoltaics, chemical sensors, biomarkers, and wavelength based biosensors.

  10. Preclinical evaluation of NETA-based bifunctional ligand for radioimmunotherapy applications using 212Bi and 213Bi: Radiolabeling, serum stability, and biodistribution and tumor uptake studies

    International Nuclear Information System (INIS)

    Introduction: Despite the great potential of targeted α-radioimmunotherapy (RIT) as demonstrated by pre-clinical and clinical trials, limited progress has been made on the improvement of chelation chemistry for 212Bi and 213Bi. A new bifunctional ligand 3p-C-NETA was evaluated for targeted α RIT using 212Bi and 213Bi. Methods: Radiolabeling of 3p-C-NETA with 205/6Bi, a surrogate of 212Bi and 213Bi, was evaluated at pH 5.5 and room temperature. In vitro stability of the 205/6Bi-3p-C-NETA-trastuzumab conjugate was evaluated using human serum (pH 7, 37 °C). Immunoreactivity and specific activity of the 205/6Bi-3p-C-NETA-trastuzumab conjugate were measured. An in vivo biodistribution study was performed to evaluate the in vivo stability and tumor targeting properties of the 205/6Bi-3p-C-NETA-trastuzumab conjugate in athymic mice bearing subcutaneous LS174T tumor xenografts. Result: The 3p-C-NETA-trastuzumab conjugate was extremely rapid in complexing with 205/6Bi, and the corresponding 205/6Bi-3p-C-NETA-trastuzumab was stable in human serum. 205/6Bi-3p-C-NETA-trastuzumab was prepared with a high specific activity and retained immunoreactivity. 205/6Bi-3p-C-NETA-trastuzumab conjugate displayed excellent in vivo stability and targeting as evidenced by low normal organ and high tumor uptake. Conclusion: The results of the in vitro and in vivo studies indicate that 3p-C-NETA is a promising chelator for RIT applications using 212Bi and 213Bi. Further detailed in vivo evaluations of 3p-C-NETA for targeted α RIT are warranted

  11. Extremal Limits and Kerr Spacetime

    CERN Document Server

    Pradhan, Parthapratim

    2013-01-01

    We study Innermost Stable Circular Orbits (ISCO) in extremal Kerr spacetime which lie close (in terms of the radial coordinate) to the event horizon and compare these with similar orbits in the near-extremal situation. Extremization of the effective potential for timelike circular orbits shows the existence of a stable circular geodesics in the extremal spacetime, precisely {\\it on} the event horizon in terms of the radial coordinate. This type of geodesics is unstable in the corresponding near-extremal spacetime as we show here, testifying to differences between the extremal limit of a generic Kerr spacetime and the exactly extremal geometry. Another aspect of the extremization of the effective potential for null circular orbits shows the existence of an unstable circular geodesic due to the axisymmetry of the spacetime in the extremal Kerr black hole. We attempt to relate this to the fact that the extremal Kerr black hole spacetime possesses no outer trapped surface.

  12. Hexadentate bispidine derivatives as versatile bifunctional chelate agents for copper(II) radioisotopes.

    Science.gov (United States)

    Juran, Stefanie; Walther, Martin; Stephan, Holger; Bergmann, Ralf; Steinbach, Jörg; Kraus, Werner; Emmerling, Franziska; Comba, Peter

    2009-02-01

    The preparation and use of bispidine derivatives (3,7-diazabicyclo[3.3.1]nonane) as chelate ligands for radioactive copper isotopes for diagnosis (64Cu) or therapy (67Cu) are reported. Starting from the hexadentate bispidine-based bis(amine)tetrakis(pyridine) ligand 1 with a keto and two ester substituents, the corresponding mono-ol 2 and two dicarboxylic acid derivatives 3 and 5 have been synthesized. A range of techniques, including single-crystal X-ray structure analysis, UV/vis spectroscopy, cyclic voltammetry, thin-layer- (TLC), and high-performance liquid chromatography (HPLC), have been used to characterize the structure and stability of the copper(II)-bispidine complexes. A rapid formation (within 1 min) of stable copper(II)-bispidine complexes under mild conditions (ambient temperature, aqueous solution) has been observed. Challenge experiments of these complexes in the presence of a high excess of competing ligands, such as glutathione, cyclam, or superoxide dismutase (SOD), as well as in rat plasma, gave no evidence of demetalation or transchelation. The bifunctional bispidine derivative 5 can be readily functionalized with biologically active molecules at the pendant carboxylate groups. The coupling of a bombesin analogue betahomo-Glu-betaAla-betaAla-[Cha(13),Nle(14)]BBN(7-14), by condensation of a carboxylate of the bispidine backbone with the N-terminus of the peptide produced the bifunctional ligand 6. The radiocopper(II) complex of this bombesin-bispidine conjugate has a considerable hydrophilicity (log D(o/w) < -2.4), and this leads to a very fast blood clearance (blood: 0.28 +/- 0.02 SUV, 1 h p.i.), low liver tissue accumulation (liver: 1.20 +/- 0.27 SUV, 1 h p.i.), and rapid renal-urinary excretion (kidneys: 6.06 +/- 2.96 SUV, 1 h p.i.) as shown by biodistribution studies of 64Cu-6 in Wistar rats. Preliminary in vivo studies of 64Cu-6 in NMRI nu/nu mice, bearing the human prostate tumor PC-3 showed an accumulation of the conjugate in the tumor (2

  13. Extreme Photonics & Applications

    CERN Document Server

    Hall, Trevor J; Paredes, Sofia A

    2010-01-01

    "Extreme Photonics & Applications" arises from the 2008 NATO Advanced Study Institute in Laser Control & Monitoring in New Materials, Biomedicine, Environment, Security and Defense. Leading experts in the manipulation of light offered by recent advances in laser physics and nanoscience were invited to give lectures in their fields of expertise and participate in discussions on current research, applications and new directions. The sum of their contributions to this book is a primer for the state of scientific knowledge and the issues within the subject of photonics taken to the extreme frontiers: molding light at the ultra-finest scales, which represents the beginning of the end to limitations in optical science for the benefit of 21st Century technological societies. Laser light is an exquisite tool for physical and chemical research. Physicists have recently developed pulsed lasers with such short durations that one laser shot takes the time of one molecular vibration or one electron rotation in an ...

  14. Non-extremal branes

    Directory of Open Access Journals (Sweden)

    Pablo Bueno

    2015-04-01

    Full Text Available We prove that for arbitrary black brane solutions of generic Supergravities there is an adapted system of variables in which the equations of motion are exactly invariant under electric–magnetic duality, i.e. the interchange of a given extended object by its electromagnetic dual. We obtain thus a procedure to automatically construct the electromagnetic dual of a given brane without needing to solve any further equation. We apply this procedure to construct the non-extremal (p,q-string of Type-IIB String Theory (new in the literature, explicitly showing how the dual (p,q-five-brane automatically arises in this construction. In addition, we prove that the system of variables used is suitable for a generic characterization of every double-extremal Supergravity brane solution, which we perform in full generality.

  15. Extreme interfacial waves

    OpenAIRE

    Grimshaw, R. H. J.; Pullin, D. I.

    1986-01-01

    Numerical solutions are presented for large-amplitude interfacial waves of extreme form on the interface between two fluids of different densities in the Boussinesq approximation. The flow in the lower fluid is irrotational, but the upper fluid may have constant, nonzero vorticity. Only symmetric waves are calculated. The results suggest limiting wave profiles for which separate portions of the interface touch, forming stagnant zones of one fluid imbedded in the other fluid.

  16. Solar extreme events

    OpenAIRE

    Hudson, Hugh S.

    2015-01-01

    Solar flares and CMEs have a broad range of magnitudes. This review discusses the possibility of "extreme events," defined as those with magnitudes greater than have been seen in the existing historical record. For most quantitative measures, this direct information does not extend more than a century and a half into the recent past. The magnitude distributions (occurrence frequencies) of solar events (flares/CMEs) typically decrease with the parameter measured or inferred (peak flux, mass, e...

  17. Extremes in nature

    CERN Document Server

    Salvadori, Gianfausto; Kottegoda, Nathabandu T

    2007-01-01

    This book is about the theoretical and practical aspects of the statistics of Extreme Events in Nature. Most importantly, this is the first text in which Copulas are introduced and used in Geophysics. Several topics are fully original, and show how standard models and calculations can be improved by exploiting the opportunities offered by Copulas. In addition, new quantities useful for design and risk assessment are introduced.

  18. A novel bifunctional N-acetylglutamate synthase-kinase from Xanthomonas campestris that is closely related to mammalian N-acetylglutamate synthase

    Directory of Open Access Journals (Sweden)

    Tuchman Mendel

    2007-04-01

    Full Text Available Abstract Background In microorganisms and plants, the first two reactions of arginine biosynthesis are catalyzed by N-acetylglutamate synthase (NAGS and N-acetylglutamate kinase (NAGK. In mammals, NAGS produces an essential activator of carbamylphosphate synthetase I, the first enzyme of the urea cycle, and no functional NAGK homolog has been found. Unlike the other urea cycle enzymes, whose bacterial counterparts could be readily identified by their sequence conservation with arginine biosynthetic enzymes, mammalian NAGS gene was very divergent, making it the last urea cycle gene to be discovered. Limited sequence similarity between E. coli NAGS and fungal NAGK suggests that bacterial and eukaryotic NAGS, and fungal NAGK arose from the fusion of genes encoding an ancestral NAGK (argB and an acetyltransferase. However, mammalian NAGS no longer retains any NAGK catalytic activity. Results We identified a novel bifunctional N-acetylglutamate synthase and kinase (NAGS-K in the Xanthomonadales order of gamma-proteobacteria that appears to resemble this postulated primordial fusion protein. Phylogenetic analysis indicated that xanthomonad NAGS-K is more closely related to mammalian NAGS than to other bacterial NAGS. We cloned the NAGS-K gene from Xanthomonas campestis, and characterized the recombinant NAGS-K protein. Mammalian NAGS and its bacterial homolog have similar affinities for substrates acetyl coenzyme A and glutamate as well as for their allosteric regulator arginine. Conclusion The close phylogenetic relationship and similar biochemical properties of xanthomonad NAGS-K and mammalian NAGS suggest that we have identified a close relative to the bacterial antecedent of mammalian NAGS and that the enzyme from X. campestris could become a good model for mammalian NAGS in structural, biochemical and biophysical studies.

  19. Deinococcus radiodurans bacteria of extreme;Deinococcus radiodurans bacterie de l'extreme

    Energy Technology Data Exchange (ETDEWEB)

    Pellay, F.X.; Matic, I.

    2010-05-15

    Extreme levels of radiation, desiccation, oxidative stress, Deinococcus radiodurans can survive in environments that degrade or damage DNA, proteins and virtually all macromolecules of life. To survive these conditions, Deinococcus have developed systems of protection, repair and recycling of exceptional efficiency. (N.C.)

  20. Bifunctional silica nanoparticles for the exploration of biofilms of Pseudomonas aeruginosa.

    Science.gov (United States)

    Mauline, L; Gressier, M; Roques, C; Hammer, P; Ribeiro, S J L; Caiut, J M A; Menu, M-J

    2013-01-01

    Luminescent silica nanoparticles are frequently employed for biotechnology applications mainly because of their easy functionalization, photo-stability, and biocompatibility. Bifunctional silica nanoparticles (BSNPs) are described here as new efficient tools for investigating complex biological systems such as biofilms. Photoluminescence is brought about by the incorporation of a silylated ruthenium(II) complex. The surface properties of the silica particles were designed by reaction with amino-organosilanes, quaternary ammonium-organosilanes, carboxylate-organosilanes and hexamethyldisilazane. BSNPs were characterized extensively by DRIFT, (13)C and (29)Si solid state NMR, XPS, and photoluminescence. Zeta potential and contact angle measurements exhibited various surface properties (hydrophilic/hydrophobic balance and electric charge) according to the functional groups. Confocal laser scanning microscopy (CLSM) measurements showed that the spatial distribution of these nanoparticles inside a biofilm of Pseudomonas aeruginosa PAO1 depends more on their hydrophilic/hydrophobic characteristics than on their size. CLSM observations using two nanosized particles (25 and 68 nm) suggest that narrow diffusion paths exist through the extracellular polymeric substances matrix. PMID:23805884

  1. Antimutagenic activities of two suspected anticarcinogenic bifunctional organoiron seleno-terephthalate derivatives.

    Science.gov (United States)

    Maslat, Ahmed O; Jibril, Ibrahim; Mizyed, Shehdeh

    2010-07-01

    Two newly bifunctional organoiron seleno-terephthalate derivatives (S1 and S2) were synthesized as potential anticarcinogenic compounds. In a previous study, they were found to have antibacterial and/or antifungal activity, while they did not show any mutagenic action. Such compounds were investigated in the present study for their antimutagenic activity. Sodium azide, hydrogen peroxide, and 4-nitro-o-phenylenediamine, as known mutagens for strains TA100, TA102, and TA98 of Salmonella typhimurium, respectively, were used. Both (S1 and S2) compounds showed a strong antimutagenic action of >98% against sodium azide, >70% against hydrogen peroxide, and >65% activity against 4-nitro-o-phenylenediamine. Bearing in mind the strong correlation between mutagenicity and carcinogenicity, the above compounds can be considered as potentially promising anticarcinogens. Therefore, the present results are very encouraging to investigate the above compounds for other biological activities, including their evaluation as anticarcinogens. A suggested mechanism for the antimutagenicity of the tested compounds is presented. PMID:20462347

  2. Composite Films of Poly(vinyl alcohol) and Bifunctional Cross-linking Cellulose Nanocrystals.

    Science.gov (United States)

    Sirviö, Juho Antti; Honkaniemi, Samuli; Visanko, Miikka; Liimatainen, Henrikki

    2015-09-01

    Long and flexible cellulose nanofibrils or stiff and short cellulose nanocrystals (CNCs) are both promising lightweight materials with high strength and the potential to serve as reinforcing agents in many polymeric materials. In this study, bifunctional reactive cellulose nanocrystals (RCNCs) with carboxyl and aldehyde functionalities were used as reinforcements to prepare acetal-bonding cross-linked poly(vinyl alcohol) (PVA) films. Two RCNCs were obtained through the mechanical homogenization of partially carboxylated dialdehyde cellulose (DAC) with a residual aldehyde content of 0.55 and 1.93 mmol/g and a carboxyl content of 1.65 and 1.93 mmol/g, respectively. The mechanical, thermal, and barrier properties of PVA-RCNC films with a variable mass ratio of RCNCs (0.5-10%) were determined. Reference CNCs without reactive aldehydes were obtained through the reduction of aldehyde functionalities to primary hydroxide groups, and their reinforcing effect was compared to RCNCs. With the addition of 10% acetal-bonding RCNCs with respect to PVA weight, the tensile strength and Young's modulus were up to 2-fold greater than those of pure PVA film. An addition of only 0.5% RCNCs improved the tensile strength of the PVA film by 66% and the modulus by 61%. In comparison, a significantly lower reinforcing effect (19% with CNC loading of 0.5%) was found using reference CNCs. PVA's effective oxygen barrier and thermal properties were preserved when RCNCs were introduced into the films. PMID:26280660

  3. Bifunctional nanoparticles for surface-enhanced Raman spectroscopy-based leukemia biomarker detection

    Science.gov (United States)

    Mehn, Dora; Morasso, Carlo; Vanna, Renzo; Schiumarini, Domitilla; Bedoni, Marzia; Ciceri, Fabio; Gramatica, Furio

    2014-03-01

    The Wilms tumor gene (WT1) is a biomarker overexpressed in more than 90% of acute myeloid leukemia patients. Fast and sensitive detection of the WT1 in blood samples would allow monitoring of the minimal residual disease during clinical remission and would permit early detection of a potential relapse in acute myeloid leukemia. In this work, Surface Enhanced Raman Spectroscopy (SERS) based detection of the WT1 sequence using bifunctional, magnetic core - gold shell nanoparticles is presented. The classical co-precipitation method was applied to generate magnetic nanoparticles which were coated with a gold shell after modification with aminopropyltriethoxy silane and subsequent deposition of gold nanoparticle seeds. Simple hydroquinone based reduction procedure was applied for the shell growing in water based reaction mixture at room temperature. Thiolated ssDNA probes of the WT1 sequence were immobilized as capture oligonucleotides on the gold surface. Malachite green was applied both for testing the amplification performance of the core-shell colloidal SERS substrate and also as label dye of the target DNA sequence. The SERS enhancer efficacy of the core-shell nanomaterial was compared with the efficacy of classical spherical gold particles produced using the conventional citrate reduction method. The core-shell particles were found not only to provide an opportunity for facile separation in a heterogeneous reaction system but also to be superior regarding robustness as SERS enhancers.

  4. Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

    Energy Technology Data Exchange (ETDEWEB)

    Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

    2012-06-15

    Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

  5. Directed assembly of bifunctional silica-iron oxide nanocomposite with open shell structure.

    Science.gov (United States)

    Che, Hui Xin; Yeap, Swee Pin; Osman, Mohamed Syazwan; Ahmad, Abdul Latif; Lim, JitKang

    2014-10-01

    The synthesis of nanocomposite with controlled surface morphology plays a key role for pollutant removal from aqueous environments. The influence of the molecular size of the polyelectrolyte in synthesizing silica-iron oxide core-shell nanocomposite with open shell structure was investigated by using dynamic light scattering, atomic force microscopy, and quartz crystal microbalance with dissipation (QCM-D). Here, poly(diallydimethylammonium chloride) (PDDA) was used to promote the attachment of iron oxide nanoparticles (IONPs) onto the silica surface to assemble a nanocomposite with magnetic and catalytic bifunctionality. High molecular weight PDDA tended to adsorb on silica colloid, forming a more extended conformation layer than low molecular weight PDDA. Subsequent attachment of IONPs onto this extended PDDA layer was more randomly distributed, forming isolated islands with open space between them. By taking amoxicillin, an antibiotic commonly found in pharmaceutical waste, as the model system, better removal was observed for silica-iron oxide nanocomposite with a more extended open shell structure. PMID:25198872

  6. The rigid bi-functional sail, new concept concerning the reduction of the drag of ships

    Science.gov (United States)

    Țicu, I.; Popa, I.; Ristea, M.

    2015-11-01

    The policy of the European Union in the energy field, for the period to follow until 2020, is based on three fundamental objectives: sustainability, competitiveness and safety in energy supply. The “Energy - Climate Changes” program sets out a number of objectives for the EU for the year 2020, known as the “20-20-20 objectives”, namely: the reduction of greenhouse gas emissions by at least 20% from the level of those of 1990, a 20% increase in the share of renewable energy sources out of the total energy consumption as well as a target of 10% biofuels in the transports energy consumption. In this context, in order to produce or save a part of the propulsive power produced by the main propulsion machinery, by burning fossil fuels, we suggest the equipping of vessels designed for maritime transport with a bi-functional rigid sail. We consider that this device may have both the role of trapping wind energy and the role of acting as a deflector for reducing the resistance of the vessel's proceeding through the water by conveniently using the bow air current, as a result of the vessel's heading through the water with significant advantage in reducing the energy consumption for propulsion insurance.

  7. Carboxylation and Decarboxylation of Aluminum Oxide Nanoparticles Using Bifunctional Carboxylic Acids and Octylamine

    Directory of Open Access Journals (Sweden)

    Shirin Alexander

    2016-01-01

    Full Text Available The carboxylation of alumina nanoparticles (NPs, with bifunctional carboxylic acids, provides molecular anchors that are used for building more complexed structures via either physisorption or chemisorption. Colloidal suspensions of the NPs may be prepared by covalently bonding a series of carboxylic acids with secondary functional groups (HO2C-R-X to the surface of the NPs: lysine (X = NH2, p-hydroxybenzoic acid (X = OH, fumaric acid (X = CO2H, and 4-formylbenzoic acid (X = C(OH. Subsequent reaction with octylamine at either 25°C or 70°C was investigated. Fourier transform IR-attenuated reflectance spectroscopy (FTIR-ATR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM along with energy dispersive X-ray (EDX analysis were used to characterize the bifunctionalized monolayers and/or multilayer corona surrounding the alumina NPs and investigate the reaction mechanism of octylamine with the functional groups (X of the NPs. Except for the fumaric functionalized NPs, addition of octylamine to the functionalized NPs leads to removal of excess carboxylic acid corona from the surface via an amide formation. The extent of the multilayer is dependent on the strength of the acid⋯acid interaction.

  8. Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

    2014-06-01

    A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV). PMID:24884171

  9. Mechanism of tetralin ring opening and contraction over bifunctional Ir/SiO₂-Al₂O₃ Catalysts.

    Science.gov (United States)

    Piccolo, Laurent; Nassreddine, Salim; Toussaint, Guy; Geantet, Christophe

    2012-09-01

    The development of cleaner fuels from conventional resources requires the finding of new hydrotreatment processes able to improve the combustion performances of fuels and limit undesirable emissions. In the context of gas oil upgrading by selective ring opening, we have investigated the hydroconversion of tetralin over iridium nanoparticles supported on amorphous silica-alumina. The conversion of tetralin leads to hydrogenation, ring-contraction, and ring-opening products. The selectivity to ring-opening/-contraction products (ROCPs) increases linearly with the acid-metal site ratio and can be tuned by modifying the metal loading, the metal nanoparticle size, or the support composition. From the combination of catalytic tests at variable conversion and the products identification by two-dimensional gas chromatography, a mechanistic reaction scheme has been established. Aromatic ROCPs are formed through purely acidic steps, whereas the formation of saturated ROCPs mostly involves bifunctional reaction steps. Iridium-catalyzed hydrogenolysis appears to be a minor pathway with respect to iridium-catalyzed hydrogenation and Brønsted acid catalyzed isomerization. PMID:22949005

  10. Fe3O4 and CdS based bifunctional core–shell nanostructure

    International Nuclear Information System (INIS)

    Highlights: ► First report on a room temperature aqueous process for growth of a hybrid core shell nanostructure containing a magnetic core and a semiconducting shell. ► Formation of distinct core shell nanostructure revealed by high resolution transmission electron microscopy. ► A bifunctional nature combining magnetic as well as photoresponce for the as synthesised core shell nanostructures demonstrated. ► A tendency towards self organisation of the core–shell nanostructure. ► Possible applications including purification and isolation of biological materials, drug delivery system, bio-labels, spintronics, etc. -- Abstract: A room temperature solution process for synthesis of Fe3O4 nanoparticles and their hybrid core shell nanostructures using CdS as the shell material has been described. The as grown particles have been characterised using XRD, Rietveld refinement, high resolution transmission electron microscopy, atomic force microscopy, superconducting quantum interference device, optical absorbance and photoluminescence spectroscopy. A superparamagnetic response revealed from the magnetisation measurements of the as synthesised magnetite nanoparticles was retained even after the growth of the CdS shell. From luminescence and high resolution atomic force microscopy measurements, it is shown that the core–shell structures advantageously combine magnetic as well as fluorescence response with a tendency towards self-organization.

  11. A new bifunctional hybrid nanostructure as an active platform for photothermal therapy and MR imaging.

    Science.gov (United States)

    Khafaji, Mona; Vossoughi, Manouchehr; Hormozi-Nezhad, M Reza; Dinarvand, Rassoul; Börrnert, Felix; Irajizad, Azam

    2016-01-01

    As a bi-functional cancer treatment agent, a new hybrid nanostructure is presented which can be used for photothermal therapy by exposure to one order of magnitude lower laser powers compared to similar nanostructures in addition to substantial enhancment in magnetic resonance imaging (MRI) contrast. This gold-iron oxide hybrid nanostructure (GIHN) is synthesized by a cost-effective and high yield water-based approach. The GIHN is sheilded by PEG. Therefore, it shows high hemo and biocompatibility and more than six month stability. Alongside earlier nanostructures, the heat generation rate of GIHN is compareable with surfactnat-capped gold nanorods (GNRs). Two reasons are behind this enhancement: Firstly the distance between GNRs and SPIONs is adjusted in a way that the surface plasmon resonance of the new nanostructure is similar to bare GNRs and secondly the fraction of GNRs is raised in the hybrid nanostructure. GIHN is then applied as a photothermal agent using laser irradiation with power as low as 0.5 W.cm(-2) and only 32% of human breast adenocarcinoma cells could survive. The GIHN also acts as a dose-dependent transvers relaxation time (T2) MRI contrast agent. The results show that the GINH can be considered as a good candidate for multimodal photothermal therapy and MRI. PMID:27297588

  12. Bifunctional separator as a polysulfide mediator for highly stable Li-S batteries

    KAUST Repository

    Abbas, Syed Ali

    2016-05-24

    The shuttling process involving lithium polysulfides is one of the major factors responsible for the degradation in capacity of lithium–sulfur batteries (LSBs). Herein, we demonstrate a novel and simple strategy—using a bifunctional separator, prepared by spraying poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on pristine separator—to obtain long-cycle LSBs. The negatively charged SO3– groups present in PSS act as an electrostatic shield for soluble lithium polysulfides through mutual coulombic repulsion, whereas PEDOT provides chemical interactions with insoluble polysulfides (Li2S, Li2S2). The dual shielding effect can provide an efficient protection from the shuttling phenomenon by confining lithium polysulfides to the cathode side of the battery. Moreover, coating with PEDOT:PSS transforms the surface of the separator from hydrophobic to hydrophilic, thereby improving the electrochemical performance. We observed an ultralow decay of 0.0364% per cycle when we ran the battery for 1000 cycles at 0.25 C—far superior to that of the pristine separator and one of the lowest recorded values reported at a low current density. We examined the versatility of our separator by preparing a flexible battery that functioned well under various stress conditions; it displayed flawless performance. Accordingly, this economical and simple strategy appears to be an ideal platform for commercialization of LSBs.

  13. Cobalt Phosphide Hollow Polyhedron as Efficient Bifunctional Electrocatalysts for the Evolution Reaction of Hydrogen and Oxygen.

    Science.gov (United States)

    Liu, Mengjia; Li, Jinghong

    2016-01-27

    The development of efficient and low-cost hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts for renewable-energy conversion techniques is highly desired. A kind of hollow polyhedral cobalt phosphide (CoP hollow polyhedron) is developed as efficient bifunctional electrocatalysts for HER and OER templated by Co-centered metal-organic frameworks. The as-prepared CoP hollow polyhedron, which have large specific surface area and high porosity providing rich catalytic active sites, show excellent electrocatalytic performances for both HER and OER in acidic and alkaline media, respectively, with onset overpotentials of 35 and 300 mV, Tafel slopes of 59 and 57 mV dec(-1), and a current density of 10 mA cm(-2) at overpotentials of 159 and 400 mV for HER and OER, respectively, which are remarkably superior to those of particulate CoP (CoP particles) and comparable to those of commercial noble-metal catalysts. In addition, the CoP hollow polyhedron also show good durability after long-term operations. PMID:26711014

  14. Catalytic characterization of bi-functional catalysts derived from Pd–Mg–Al layered double hydroxides

    Indian Academy of Sciences (India)

    N N Das; S C Srivastava

    2002-08-01

    Hydrotalcite like precursors containing PdII–MgII–AlIII with varying molar ratios, (Pd + Mg)/Al ≈ 3 and Mg/Pd ≈ 750 to 35, were prepared by coprecipitation of metal nitrates at constant pH. Characterization of samples as synthesized and their calcined products by elemental analyses, powder XRD, TG–DTA, FT–IR spectroscopy, TPR and N2 physisorption indicated a well crystalline hydrotalcite like structure with incorporation of Pd2+ in the brucite layers. Thermal decomposition of hydrotalcite precursors at intermediate temperatures led to amorphous mixed oxides, Pd/MgAl(O), which on reduction yielded bi-functional catalyst, Pd°/MgAl(O). The resultant catalysts with acid, base and hydrogenating sites, were highly active and selective for one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen. The results showed an optimal balance between acid-base and metallic sites were required to increase the selectivity of MIBK and stability of the catalysts.

  15. The determination of the rate of conjugation immunoglobuline with bifunctional chelator

    Science.gov (United States)

    Málek, Z.; Miler, V.; Budský, F.

    2006-01-01

    The work was performed under the GACR project: "Technology of preparation of radionuclides and their labelled compounds for nuclear medicine and pharmacy with the use of the reactor LVR-15" reg. no. 104/03/0499. Imaging of cell’s antigens with the use of labelled immunoglobulines allows imaging of specific receptors on cell membrane and specific tumours. It is necessary to carry out the labelling of the immunoglobulines with radionuclides of suitable physical properties, which form cations (e.g., 111In, 90Y, 177Lu) that form very strong chelates of sufficiently high stability constant preventing the dissociation of complexes or the radionuclide under “in-vivo” conditions. The immunoglobuline must be conjugated with the bifunctional chelator (BCH), which contains both chelating unit and reactive group for binding to the immunoglobuline. In our laboratory we have conjugated human IgG and monoclonal antibody CD20 with diethylenetriamine pentaacetic acid dianhydride (cDTPAA). Radionuclides 90Y and 177Lu prepared on the LVR-15 reactor in NRI Rez were used for labelling. After conjugation and labelling the yields in relation to the amount of isotopic carrier have been determined.

  16. Bifunctional redox flow battery-1 V(III)/V(II)-glyoxal(O2) system

    International Nuclear Information System (INIS)

    Bifunctional redox flow batteries (BRFB) possess functions of both electricity storage and electrochemical preparation, having the potential for increasing the electrical energy utilization. A V(III)/V(II)-glyoxal(O2) system has been developed. Separators of the BRFB play a key role in BRFB performance. A Nafion solution was sprayed on a gas diffusion layer (GDL) at the Nafion loading of 2 mg cm-2, and the GDL was then hot-pressed onto a Nafion115 cation exchange membrane, obtaining a modified separator. This separator not only prevents the crossover of vanadium but also has favorable conductivity, obtaining optimal charge and organic electro-synthesis performance of the BRFB. The effects of the concentrations of glyoxal and HCl on the performance of BRFB were also investigated. It is shown that the optimal concentration of glyoxal and HCl should be 1.2 and 3 M, respectively. As a result, the current efficiency of organic electro-synthesis is further increased. An acceptable discharge performance is achieved for a period exceeding 20 h at the current density of 20 mA cm-2. The average discharge voltage of 0.73 V and the coulombic efficiency of 66% are obtained. It is demonstrated that the principle of the BRFB is feasible. However, further experiments are needed to improve the performance

  17. Bifunctional impedimetric sensors based on azodicarboxamide supported on modified graphene nanosheets.

    Science.gov (United States)

    Azadbakht, Azadeh; Roushani, Mahmoud; Abbasi, Amir Reza; Derikvand, Zohreh; Menati, Saeid

    2016-12-01

    Herein, gold-coated graphene oxide nanosheets hybrid material (GO/AuNPs) with exceptional physical and chemical properties has been utilized as a novel platform for electrode modification. The synthetic method of GO/AuNPs involves anon-covalent functionalization of exfoliated GO with AuNPs based on the reduction of the Au(III) complex by sodium citrate. The prepared GO/AuNPs hybrid exhibits the dispersion of high density AuNPs which were densely decorated on the large surface area of GO. The GO/AuNPs modified glassy carbon (GC) electrode was employed as a sensing platform to immobilize azodicarboxamide (ACA). The morphology, structure and electrochemical performance of the sensor were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that the modified electrode has a notable bifunctional catalytic activity. Electrocatalytic oxidations of cysteine and electrocatalytic reduction of iodate at the surface of modified electrode were investigated with different technique. PMID:27612707

  18. Intermolecular interactions in cyclic complexes with hydrogen bond of bifunctional N-containing compounds in solution

    International Nuclear Information System (INIS)

    The structure of molecular and ionic hydrogen-bonded complexes formed by bifunctional N-containing molecules, which can act as proton donor and proton acceptor simultaneously, and the nature of molecular interactions in these complexes were studied in solution. The spectroscopic, steric and thermodynamic characteristics of self-associates of 3,5-dimethylpyrazole, diphenylformamidine, diphenylguanidine and diphenyltriazene and complexes of these compounds with carboxylic acids were obtained. The quantum chemical calculations of the structure of complexes and the vibrational frequencies in IR spectra were carried out in the harmonic approximation and with the anharmonic effects taken into account. It was shown that under the interaction with weak carboxylic acids (HCOOH, CH3COOH, CH2ClCOOH) the complexes have molecular structure with two H-bonds NH...O=C and OH...N, and the interaction with strong acids (CHCl2COOH, CCl3COOH, CF3COOH) results in formation of cyclic hydrogen-bonded ionic pairs with proton transfer from hydroxyl group to the N atom of the azo-compound. (authors)

  19. Preparation of magnetic and fluorescent bifunctional chitosan nanoparticles for optical determination of copper ion

    International Nuclear Information System (INIS)

    We describe a simple method for the synthesis of highly magnetic and fluorescent bifunctional chitosan nanoparticles (MF-CSNPs). Water-soluble and magnetic Fe3O4-chitosan nanoparticles and CdSe quantum dots capped with thioglycolic acid were incorporated into a chitosan matrix via electrostatic interaction. The optical, magnetic, crystallographic and morphological properties of the new nanoparticles were studied by UV-visible, fluorescence, X-ray diffraction and transmission electron microscopy. In addition, MF-CSNPs are found to be a useful probe for the determination of copper ion which acts as a quencher of fluorescence. The relative fluorescence intensity of MF-CSNPs is linearly related to the concentration of copper ion in the 0.125 to 25 ng.mL-1 concentration range. The MF-CSNPs also are found to adsorb copper ion which therefore can be separated and enriched by manipulating them with an external magnetic field. Before enrichment, the limit of detection (LOD) for copper ion is 120 pg.mL-1, but after enrichment, the LOD is 46 pg.mL-1. (author)

  20. Cu/Ag-based bifunctional nanoparticles obtained by one-pot laser-assisted galvanic replacement

    International Nuclear Information System (INIS)

    We have prepared, for the first time, stable and uncapped Ag/Cu-based bifunctional nanoparticles (NPs) (BFNPs) in water, by combining ps laser ablation in liquid environment and galvanic replacement. The particles were obtained in a single step by 1,064 nm irradiation of a Cu target in water solutions of AgNO3 or AgNO2. Under proper salt concentration and irradiation conditions, the laser beam activates formation of deep orange colloids, which are positively charged and stable for weeks. High resolution transmission electron microscopy (HRTEM) analysis showed a predominance of composite crystalline nanostructures with size in the 1–15 nm range and consisting of fcc Ag and fcc Cu (or its oxides). While CuO tenorite crystalline phase was detected by HRTEM, X-ray photoelectron spectroscopy analysis permitted to observe also the Cu(I) oxidation state of Cu, being the Cu(I)/Cu(II) ratio different in the samples obtained in AgNO3 or AgNO2 baths. Functionalization with organic ligands and subsequent Raman tests demonstrated the SERS activity of the BFNPs and the existence of different complexing surface sites.

  1. NAD(H recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available A chimeric bifunctional enzyme composing of galactose dehydrogenase (galDH; from Pseudomonas fluorescens and lactate dehydrogenase (LDH; from Bacillus stearothermophilus was successfully constructed. The chimeric galDH/LDH possessed dual characteristics of both galactose dehydrogenase and lactate dehydrogenase activities while exhibiting hexameric rearrangement with a molecular weight of approximately 400 kDa. In vitro observations showed that the chimeric enzyme was able to recycle NAD with a continuous production of lactate without any externally added NADH. Two fold higher recycling rate (0.3 mM/h than that of the native enzyme was observed at pH values above 8.5. Proximity effects became especially pronounced during the recycling assay when diffusion hindrance was induced by polyethylene glycol. All these findings open up a high feasibility to apply the NAD(H recycling system for metabolic engineering purposes e.g. as a model to gain a better understanding on the molecular proximity process and as the routes for synthesizing of numerous high-value-added compounds.

  2. Structure and Function of Fusicoccadiene Synthase, a Hexameric Bifunctional Diterpene Synthase.

    Science.gov (United States)

    Chen, Mengbin; Chou, Wayne K W; Toyomasu, Tomonobu; Cane, David E; Christianson, David W

    2016-04-15

    Fusicoccin A is a diterpene glucoside phytotoxin generated by the fungal pathogen Phomopsis amygdali that causes the plant disease constriction canker, first discovered in New Jersey peach orchards in the 1930s. Fusicoccin A is also an emerging new lead in cancer chemotherapy. The hydrocarbon precursor of fusicoccin A is the tricyclic diterpene fusicoccadiene, which is generated by a bifunctional terpenoid synthase. Here, we report X-ray crystal structures of the individual catalytic domains of fusicoccadiene synthase: the C-terminal domain is a chain elongation enzyme that generates geranylgeranyl diphosphate, and the N-terminal domain catalyzes the cyclization of geranylgeranyl diphosphate to form fusicoccadiene. Crystal structures of each domain complexed with bisphosphonate substrate analogues suggest that three metal ions and three positively charged amino acid side chains trigger substrate ionization in each active site. While in vitro incubations reveal that the cyclase domain can utilize farnesyl diphosphate and geranyl diphosphate as surrogate substrates, these shorter isoprenoid diphosphates are mainly converted into acyclic alcohol or hydrocarbon products. Gel filtration chromatography and analytical ultracentrifugation experiments indicate that full-length fusicoccadiene synthase adopts hexameric quaternary structure, and small-angle X-ray scattering data yield a well-defined molecular envelope illustrating a plausible model for hexamer assembly. PMID:26734760

  3. Exact functional derivative of the nonadditive kinetic-energy bifunctional in the long-distance limit

    Science.gov (United States)

    Jacob, Christoph R.; Beyhan, S. Maya; Visscher, Lucas

    2007-06-01

    We have investigated the functional derivative of the nonadditive kinetic-energy bifunctional, which appears in the embedding potential that is used in the frozen-density embedding formalism, in the limit that the separation of the subsystems is large. We have derived an exact expression for this kinetic-energy component of the embedding potential and have applied this expression to deduce its exact form in this limit. Comparing to the approximations currently in use, we find that while these approximations are correct at the nonfrozen subsystem, they fail completely at the frozen subsystem. Using test calculations on two model systems, a H2O⋯Li+ complex and a cluster of aminocoumarin C151 surrounded by 30 water molecules, we show that this failure leads to a wrong description of unoccupied orbitals, which can lead to convergence problems caused by too low-lying unoccupied orbitals and which can further have serious consequences for the calculation of response properties. Based on our results, a simple correction is proposed, and we show that this correction is able to fix the observed problems for the model systems studied.

  4. Bifunctional polyacrylonitrile fiber-mediated conversion of sucrose to 5-hydroxymethylfurfural in mixed-aqueous systems.

    Science.gov (United States)

    Shi, Xian-Lei; Zhang, Min; Lin, Huikun; Tao, Minli; Li, Yongdan; Zhang, Wenqin

    2015-03-01

    A highly efficient catalytic system composed of a bifunctional polyacrylonitrile fiber (PANF-PA[BnBr]) and a metal chloride was employed to produce 5-hydroxymethylfurfural (HMF) from sucrose in mixed-aqueous systems. The promoter of PANF-PA[BnBr] incorporates protonic acid groups that promote the hydrolysis of the glycosidic bond to convert sucrose into glucose and fructose, and then catalyzes fructose dehydration to HMF, while the ammonium moiety may promote synergetically with the metal chloride the isomerization of glucose to fructose and transfer HMF from the aqueous to the organic phase. The detailed characterization by elemental analysis, FTIR spectroscopy, and SEM confirmed the rangeability of the fiber promoter during the modification and utilization processes. Excellent results in terms of high yield (72.8%) of HMF, superior recyclability (6 cycles) of the process, and effective scale-up and simple separation procedures of the catalytic system were obtained. Moreover, the prominent features (high strength, good flexibility, etc.) of the fibers are very attractive for fix-bed reactor. PMID:25573698

  5. Impedimetric and amperometric bifunctional glucose biosensor based on hybrid organic-inorganic thin films.

    Science.gov (United States)

    Wang, Huihui; Ohnuki, Hitoshi; Endo, Hideaki; Izumi, Mitsuru

    2015-02-01

    A novel glucose biosensor with an immobilized mediator was studied using electrochemical impedance spectroscopy (EIS) and amperometry measurements. The biosensor has a characteristic ultrathin form and is composed of a self-assembled monolayer anchoring glucose oxidase (GOx) covered with Langmuir-Blodgett (LB) films of Prussian blue (PB). The immobilized PB in the LB films acts as a mediator and enables the biosensor to work under a low potential (0.0V vs. Ag/AgCl). In the EIS measurements, a dramatic decrease in charge transfer resistance (Rct) was observed with sequential addition of glucose, which can be attributed to enzymatic activity. The linearity of the biosensor response was observed by the variation of the sensor response (1/Rct) as a function of glucose concentration in the range 0 to 25mM. The sensor also showed linear amperometric response below 130mM glucose. The organic-inorganic system of GOx and PB nanoclusters demonstrated bifunctional sensing action, both amperometry and EIS modes, as well as long sensing stability for 4 days. PMID:25014167

  6. Extreme Programming Pocket Guide

    CERN Document Server

    Chromatic

    2003-01-01

    Extreme Programming (XP) is a radical new approach to software development that has been accepted quickly because its core practices--the need for constant testing, programming in pairs, inviting customer input, and the communal ownership of code--resonate with developers everywhere. Although many developers feel that XP is rooted in commonsense, its vastly different approach can bring challenges, frustrations, and constant demands on your patience. Unless you've got unlimited time (and who does these days?), you can't always stop to thumb through hundreds of pages to find the piece of info

  7. Extreme Lateral Interbody Fusion Procedure

    Medline Plus

    Full Text Available ... for spine surgery called XLIF, extreme lateral interbody fusion. Dr. Juan Uribe will perform the procedure. Dr. ... A better term would be extreme lateral interbody fusion. This is a procedure that has been performed ...

  8. Gadolinium and fluorescent bi-functionally labeling and in vitro MRI of rat bone marrow mesenchymal stem cells

    International Nuclear Information System (INIS)

    Objective: To determine the feasibility of magnetically labeling and tracking mesenchymal stem cells (MSCs) in vitro by using a gadolinium and fluorescent bi-functionally transfection agent of polyethylenimine. Methods: A gadolinium bifunctional transfection reagent complex was obtained after the linear polyethylenimine derivative (JetPEI-FluoR) was incubated with Gd-DTPA. Mesenchymal stem cells isolated from the bone marrows of SD rats were cultured and expanded. The mesenchymal stem cells were incubated with the bi-functional labeling agents. After labeling, the MSCs were examined with fluoroscope and electron microscope and the biological characters were detected including trypan blue exclusion test, MTT, and apoptosis detection. On a 1.5 T MR system, the labeled MSCs were examined with spin echo T1WI and T2WI and T1 measurement with mixed sequence. After labeling, the cells were cultured and undergone routine passage. Prior MR examinations were repeated for each passage of labeled cells. All data was statistically prolessed with SPSS for Windows. Results: Of 5 x 105 MSCs incubated with the bi-functional agents, 4.25 x 105 MSCs were successfully labeled, the percentage of labeled MSCs was 85% fluoroscopically. The high density electron particles of gadolinium observed electron microscopically existed around cellular apparatuses, especially around Golgi apparatus. In trypan blue exclusion test, the exclusion rate of labeled MSCs with incubation duration of 3,6,12,24 h was (96.55±2.90)%, (94.17± 2.56)%, (97.16±3.12)% and (94.23±2.67)%, respectively. The corresponding exclusion rate of unlabeled MSCs was (95.86±2.67)%, (92.04±2.21)%, (93.38±3.64)% and (92.12±2.53)%, respectively. There was no statistical difference of trypan blue exclusion rate between labeled cells and control unlabeled cells within 24 hours of incubation (F=4.523, P>0.05). In the proliferation test, the optical absorption value of labeled MSC with 2.5, 5.0, 10.0, 20.0, 30.0 and 40.0

  9. Facile preparation of Ag-Cu bifunctional electrocatalysts for zinc-air batteries

    International Nuclear Information System (INIS)

    Highlights: • Ag-Cu dendrites are observed for the first time to exhibit high catalytic activity for oxygen reduction reaction. • Ag-Cu dendrites are directly synthesized through galvanic displacement on the current collector layer made of Ni foams. • A bifunctional air cathode is fabricated using Ag-Cu dendrites as a carbon-free, binder-free catalyst layer. • Both the primary and rechargeable zinc–air batteries fabricated by Ag-Cu catalysts exhibit excellent performance. - ABSTRACT: An inexpensive, facile galvanic displacement reaction for the direct growth of silver–copper (Ag-Cu) catalysts on nickel foams is developed for the first time. The resulting Ag-Cu catalysts exhibit dendritic morphologies. Ag and Cu atoms are in their metallic state while the presence of CuO and Cu2O are limited on the surface of catalyst. The catalysts demonstrate high catalytic activity for oxygen reduction reaction (ORR) in alkaline solution, as evaluated by both linear scanning voltammetry and rotating disk electrode polarization measurements. The ORR catalysed by Ag-Cu catalyst in alkaline solution proceeds through a four-electron pathway. An air cathode is fabricated using Ag-Cu catalyst as a carbon-free, binder-free catalyst layer. Using this Ag-Cu catalyst based air cathode, both the primary and rechargeable zinc-air batteries show excellent battery performance. The specific capacity of the primary zinc-air battery is 572 mAh g−1. Especially, the rechargeable zinc-air battery shows high round-trip efficiency, appealing stability at a long charge-discharge cycle period

  10. Modification of bifunctional epoxy resin using CO{sub 2} fixation process and nanoclay

    Energy Technology Data Exchange (ETDEWEB)

    Khoshkish, Morteza; Bouhendi, Hosein, E-mail: H.boohendi@ippi.ac.ir; Vafayan, Mehdi

    2014-10-15

    A bifunctional epoxy resin was modified by using a CO{sub 2} fixation solution process in the presence of tetra n-butyl ammonium bromide (TBAB) as catalyst and the modified treated resin was treated by cloisite 30B as nano additive. The Unmodified epoxy resin (UME), CO{sub 2} fixated modified epoxy resin (CFME), and CFME/clay nano composite (CFMEN), were cured by diethylenetriamine (DETA). A cycloaliphatic compound as a reactive diluent was used to control the viscosity of high viscose CFME. The exfoliation of organoclay in UME and CFME was investigated by X-ray diffraction and activation energy was computed using the advanced integral isoconversional method. The activation energy dependency demonstrated that the mechanism of UME curing did not change in the presence of nanoclay. In contrast, the CO{sub 2} fixation results showed a significant change in the activation energy dependency. The Thermal stability parameters include the initial degradation temperature (IDT), the temperature at the maximum rate of weight loss (T{sub max}), and the decomposition activation energy (E{sub d}) were determined by thermal gravimetry analysis. Dynamic mechanical thermal analysis measurements showed that the presence of organoclay in CFME increases the T{sub g} of nano composite in contrast to UME. The fracture roughness of UME, CFME and CFNE were determined by scanning electron microscope. The exfoliated UME/1%clay nanocomposite was confirmed by TEM image. - Highlights: • A new epoxy resin was synthesized using CO{sub 2} fixation reaction. • The synthesized epoxy resin was modified by an organo nano-clay. • CO{sub 2} fixation noticeably changed the curing mechanism. • CO{sub 2} fixation reaction consumes CO{sub 2} which is a harmful greenhouse gas.

  11. Novel bifunctional anthracycline and nitrosourea chemotherapy for human bladder cancer: analysis in a preclinical survival model.

    Science.gov (United States)

    Glaves, D; Murray, M K; Raghavan, D

    1996-08-01

    A hybrid drug [N-2-chloroethylnitrosoureidodaunorubicin (AD312)] that combines structural and functional features of both anthracyclines and nitrosoureas was evaluated in a preclinical survival model of human bladder cancer. To measure the therapeutic activity of AD312, UCRU-BL13 transitional cell carcinoma cells were grown as xenografts in nude mice, and tumor growth rates were compared after i.v. administration of the drug at three dose levels. AD312 treatment at 45 and 60 mg/kg achieved 7-10-fold inhibition of tumor growth and increased host survival by 156 and 249%, respectively. Doses of 60 mg/kg showed optimal therapeutic efficacy, with sustained tumor growth inhibition, an over 2-fold increase in life span, and 40% of mice tumor free ("cured") at 120 days. Tumors were unresponsive to maximum tolerated doses of doxorubicin, a standard anthracycline used as a single agent and in combination therapies for bladder cancer. 1,3-Bis-[2-chloroethyl]-1-nitrosourea was used as a control for the apparently enhanced response of human tumors in murine hosts to nitrosoureas. 1, 3-Bis-[2-chloroethyl]-1-nitrosourea administered in three injections of 20 mg/kg did not cure mice but temporarily inhibited tumor growth by 70% and prolonged survival by 55%; its activity in this model suggests that it may be included in the repertoire of alkylating agents currently used for treatment of bladder cancers. AD312 showed increased antitumor activity with less toxicity than doxorubicin, and its bifunctional properties provide the opportunity for simultaneous treatment of individual cancer cells with two cytotoxic modalities as well as treatment of heterogeneous populations typical of bladder cancers. This novel cytotoxic drug cured doxorubicin-refractory disease and should be investigated for the clinical management of bladder cancer. PMID:9816302

  12. Novel configuration of bifunctional air electrodes for rechargeable zinc-air batteries

    Science.gov (United States)

    Li, Po-Chieh; Chien, Yu-Ju; Hu, Chi-Chang

    2016-05-01

    A novel configuration of two electrodes containing electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) pressed into a bifunctional air electrode is designed for rechargeable Zn-air batteries. MOC/25BC carbon paper (MOC consisting of α-MnO2 and XC-72 carbon black) and Fe0.1Ni0.9Co2O4/Ti mesh on this air electrode mainly serve as the cathode for the ORR and the anode for the OER, respectively. The morphology and physicochemical properties of Fe0.1Ni0.9Co2O4 are investigated through scanning electron microscopy, inductively coupled plasma-mass spectrometry, and X-ray diffraction. Electrochemical studies comprise linear sweep voltammetry, rotating ring-disk electrode voltammetry, and the full-cell charge-discharge-cycling test. The discharge peak power density of the Zn-air battery with the unique air electrode reaches 88.8 mW cm-2 at 133.6 mA cm-2 and 0.66 V in an alkaline electrolyte under an ambient atmosphere. After 100 charge-discharge cycles at 10 mA cm-2, an increase of 0.3 V between charge and discharge cell voltages is observed. The deep charge-discharge curve (10 h in each step) indicates that the cell voltages of discharge (1.3 V) and charge (1.97 V) remain constant throughout the process. The performance of the proposed rechargeable Zn-air battery is superior to that of most other similar batteries reported in recent studies.

  13. A metal-free bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions

    Science.gov (United States)

    Zhang, Jintao; Zhao, Zhenghang; Xia, Zhenhai; Dai, Liming

    2015-05-01

    The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are traditionally carried out with noble metals (such as Pt) and metal oxides (such as RuO2 and MnO2) as catalysts, respectively. However, these metal-based catalysts often suffer from multiple disadvantages, including high cost, low selectivity, poor stability and detrimental environmental effects. Here, we describe a mesoporous carbon foam co-doped with nitrogen and phosphorus that has a large surface area of ˜1,663 m2 g-1 and good electrocatalytic properties for both ORR and OER. This material was fabricated using a scalable, one-step process involving the pyrolysis of a polyaniline aerogel synthesized in the presence of phytic acid. We then tested the suitability of this N,P-doped carbon foam as an air electrode for primary and rechargeable Zn-air batteries. Primary batteries demonstrated an open-circuit potential of 1.48 V, a specific capacity of 735 mAh gZn-1 (corresponding to an energy density of 835 Wh kgZn-1), a peak power density of 55 mW cm-2, and stable operation for 240 h after mechanical recharging. Two-electrode rechargeable batteries could be cycled stably for 180 cycles at 2 mA cm-2. We also examine the activity of our carbon foam for both OER and ORR independently, in a three-electrode configuration, and discuss ways in which the Zn-air battery can be further improved. Finally, our density functional theory calculations reveal that the N,P co-doping and graphene edge effects are essential for the bifunctional electrocatalytic activity of our material.

  14. Crystal structure of two new bifunctional nonsubstrate type thrombin inhibitors complexed with human alpha-thrombin.

    Science.gov (United States)

    Féthière, J.; Tsuda, Y.; Coulombe, R.; Konishi, Y.; Cygler, M.

    1996-01-01

    The crystal structures of two new thrombin inhibitors, P498 and P500, complexed with human alpha-thrombin have been determined at 2.0 A resolution and refined to crystallographic R-factors of 0.170 and 0.169, respectively. These compounds, with picomolar binding constants, belong to a family of potent bifunctional inhibitors that bind thrombin at two remote sites: the active site and the fibrinogen recognition exosite (FRE). The inhibitors incorporate a nonsubstrate type active site binding fragment: Dansyl-Arg-(D)Pipecolic acid (Dns-Arg-(D)Pip), reminiscent of the active-site directed inhibitors MD-805 and MQPA, rendering them resistant to thrombin-induced hydrolysis. The FRE binding fragment of these inhibitors corresponds to the hirudin55-65 sequence. They differ in the chemical nature of the nonpeptidyl linker bridging these two functional activities. In both cases, the active site binding fragment is well defined in the electron density. The DnsH1, ArgH2, and (D)PipH3 groups occupy the S3, S1, and S2 subsites of thrombin, respectively, in a way similar to that observed in the thrombin-MQPA complexes. Binding in the active site of thrombin is characterized by numerous van der Waals contacts and ring-ring system interactions. Unlike in the substrate-like inhibitors, ArgH2 enters the S1 specificity pocket from the P2 position and adopts a bent conformation to make an hydrogen bond to the carboxylate of Asp189. In this noncanonical position, its carbonyl points away from the oxyanion hole, which is now occupied by well-ordered solvent molecules. The linkers fit in the groove extending from the active site to the FRE. The C-terminal fragments of both inhibitors bind in the same way as analogous FRE binding elements in previously described complexes. PMID:8762149

  15. Efficient Access to Chiral Benzhydrols via Asymmetric Transfer Hydrogenation of Unsymmetrical Benzophenones with Bifunctional Oxo-Tethered Ruthenium Catalysts.

    Science.gov (United States)

    Touge, Taichiro; Nara, Hideki; Fujiwhara, Mitsuhiko; Kayaki, Yoshihito; Ikariya, Takao

    2016-08-17

    A concise asymmetric transfer hydrogenation of diaryl ketones, promoted by bifunctional Ru complexes with an etherial linkage between 1,2-diphenylethylenediamine (DPEN) and η(6)-arene ligands, was successfully developed. Because of the effective discrimination of substituents at the ortho position on the aryl group, unsymmetrical benzophenones were smoothly reduced in a 5:2 mixture of formic acid and triethylamine with an unprecedented level of excellent enantioselectivity. For the non-ortho-substituted benzophenones, the oxo-tethered catalyst electronically discerned biased substrates, resulting in attractive performance yielding chiral diarylmethanols with >99% ee. PMID:27463264

  16. A Novel N-Acetylglutamate Synthase Architecture Revealed by the Crystal Structure of the Bifunctional Enzyme from Maricaulis maris

    OpenAIRE

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M.; Tuchman, Mendel

    2011-01-01

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 Å resolution indicates that it is a tetramer, in contrast t...

  17. Extreme skin depth waveguides

    CERN Document Server

    Jahani, Saman

    2014-01-01

    Recently, we introduced a paradigm shift in light confinement strategy and introduced a class of extreme skin depth (e-skid) photonic structures (S. Jahani and Z. Jacob, "Transparent sub-diffraction optics: nanoscale light confinement without metal," Optica 1, 96-100 (2014)). Here, we analytically establish that figures of merit related to light confinement in dielectric waveguides are fundamentally tied to the skin depth of waves in the cladding. We contrast the propagation characteristics of the fundamental mode of e-skid waveguides and conventional waveguides to show that the decay constant in the cladding is dramatically larger in e-skid waveguides, which is the origin of sub-diffraction confinement. Finally, we propose an approach to verify the reduced skin depth in experiment using the decrease in the Goos-H\\"anchen phase shift.

  18. Extremophiles and Extreme Environments

    Directory of Open Access Journals (Sweden)

    Pabulo Henrique Rampelotto

    2013-08-01

    Full Text Available Over the last decades, the study of extremophiles has providing ground breaking discoveries that challenge the paradigms of modern biology and make us rethink intriguing questions such as "what is life?", "what are the limits of life?", and "what are the fundamental features of life?". These findings and possibilities have made the study of life in extreme environments one of the most exciting areas of research in recent decades. However, despite the latest advances we are just in the beginning of exploring and characterizing the world of extremophiles. This special issue discusses several aspects of these fascinating organisms, exploring their habitats, biodiversity, ecology, evolution, genetics, biochemistry, and biotechnological applications in a collection of exciting reviews and original articles written by leading experts and research groups in the field.

  19. Standardization of methodology to derivatization and radiolabeling of the anti-CD20 monoclonal antibody from bifunctional chelator DOTA-NHS-Ester

    International Nuclear Information System (INIS)

    Lymphomas are cancers of the lymphatic system, being the most common the non-Hodgkin lymphoma (NHL). The Radioimmunotherapy (RIT), that increase the cytotoxic effect of monoclonal antibodies (mAb), therefore labeling these Mab with different radioisotopes. RIT combines the specificity of the antibody and the toxicity of the radionuclides. The mAb anti-CD20 is used for treatment of relapse or refractory NHL. The labeling of anti- CD20 with 177Lu, requires a bifunctional chelating agent that is designed to make a 'connect bridge' between the mAb and the radionuclide. The incorporation of the chelating group in mAb structure is called derivatization. The aim of this work is to study the derivatization of anti-CD20 antibody with DOTA-NHS-ester chelating group and labeling parameters to produce 177Lu-DOTA-Anti CD20. Five milligrams of anti-CD20 were purified by dialysis against phosphate buffer pH 8.0 and derivatized with DOTA-NHS-ester in 1:250, 1:500 and 1:1000 molar ratios. The reaction was conducted for 1 hour in gently mixing at room temperature and remained under refrigeration for 48 hours. The reaction mixture was purified in gel column Sephadex G-50 ; the aliquots that presented greater protein concentration, were mixed and concentrated. The purified antibody conjugated was added to 111-185MBq (3-5mCi) of 177LuCl3 diluted in 0.4 M acetate buffer pH 5.5. Radiochemical purity was less than 95% in all the molar ratios, indicating necessity of the purification after the labeling. The mAb derivatized showed stable when stored for to 1 month to 4 deg C and 4 days at -20 deg C. (author)

  20. The ERAD inhibitor Eeyarestatin I is a bifunctional compound with a membrane-binding domain and a p97/VCP inhibitory group.

    Directory of Open Access Journals (Sweden)

    Qiuyan Wang

    Full Text Available BACKGROUND: Protein homeostasis in the endoplasmic reticulum (ER has recently emerged as a therapeutic target for cancer treatment. Disruption of ER homeostasis results in ER stress, which is a major cause of cell death in cells exposed to the proteasome inhibitor Bortezomib, an anti-cancer drug approved for treatment of multiple myeloma and Mantle cell lymphoma. We recently reported that the ERAD inhibitor Eeyarestatin I (EerI also disturbs ER homeostasis and has anti-cancer activities resembling that of Bortezomib. METHODOLOGY AND PRINCIPAL FINDINGS: Here we developed in vitro binding and cell-based functional assays to demonstrate that a nitrofuran-containing (NFC group in EerI is the functional domain responsible for the cytotoxicity. Using both SPR and pull down assays, we show that EerI directly binds the p97 ATPase, an essential component of the ERAD machinery, via the NFC domain. An aromatic domain in EerI, although not required for p97 interaction, can localize EerI to the ER membrane, which improves its target specificity. Substitution of the aromatic module with another benzene-containing domain that maintains membrane localization generates a structurally distinct compound that nonetheless has similar biologic activities as EerI. CONCLUSIONS AND SIGNIFICANCE: Our findings reveal a class of bifunctional chemical agents that can preferentially inhibit membrane-bound p97 to disrupt ER homeostasis and to induce tumor cell death. These results also suggest that the AAA ATPase p97 may be a potential drug target for cancer therapeutics.

  1. Precipitation extremes under climate change

    CERN Document Server

    O'Gorman, Paul A

    2015-01-01

    The response of precipitation extremes to climate change is considered using results from theory, modeling, and observations, with a focus on the physical factors that control the response. Observations and simulations with climate models show that precipitation extremes intensify in response to a warming climate. However, the sensitivity of precipitation extremes to warming remains uncertain when convection is important, and it may be higher in the tropics than the extratropics. Several physical contributions govern the response of precipitation extremes. The thermodynamic contribution is robust and well understood, but theoretical understanding of the microphysical and dynamical contributions is still being developed. Orographic precipitation extremes and snowfall extremes respond differently from other precipitation extremes and require particular attention. Outstanding research challenges include the influence of mesoscale convective organization, the dependence on the duration considered, and the need to...

  2. Extreme winds in Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.

    1999-02-01

    Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity which is defined as the 50-year wind speed under standard conditions, i.e. ten-minute averages at the height 10 m over a uniform terrain with the roughness length 0.05 m. The sites are, from west, Skjern (15 years), Kegnaes (7 years), Sprogoe (20 years), and Tystofte (15 years). The data are ten minute averages of wind speed, wind direction, temperature and pressure. The last two quantities are used to determine the air density {rho}. The data are cleaned for terrain effects by means of a slightly modified WASP technique where the sector speed-up factors and roughness lengths are linearly smoothed with a direction resolution of one degree. Assuming geotropic balance, all the wind-velocity data are transformed to friction velocity u{sub *} and direction at standard conditions by means of the geotropic drag law for neutral stratification. The basic wind velocity in 30 deg. sectors are obtained through ranking of the largest values of the friction velocity pressure 1/2{rho}u{sub *}{sup 2} taken both one every two months and once every year. The main conclusion is that the basic wind velocity is significantly larger at Skjern, close to the west coast of Jutland, than at any of the other sites. Irrespective of direction, the present standard estimates of 50-year wind are 25 {+-} 1 m/s at Skern and 22 {+-} 1 m/s at the other three sites. These results are in agreement with those obtained by Jensen and Franck (1970) and Abild (1994) and supports the conclusion that the wind climate at the west coast of Jutland is more extreme than in any other part of the country. Simple procedures to translate in a particular direction sector the standard basic wind velocity to conditions with a different roughness length and height are presented. It is shown that a simple scheme makes it possible to calculate the total 50-year extreme load on a general structure without

  3. High-temperature crystallization of the secondary alcohol dehydrogenase from the extreme thermophilic bacteria Thermoanaerobacter ethanolicus, a bifunctional alcohol dehydrogenase-acetyl-CoA thio esterase

    International Nuclear Information System (INIS)

    Full text. Ethanol fermentations from Saccharomyces sp. are used in industrial ethanol production and are performed at mesophilic temperatures where final ethanol concentrations must exceed 4% (v/v) to make the process industrially economic. In addition, distillation is required to recover ethanol. Thermophilic fermentations are very attractive since they enable separation of ethanol from continuous cultures at process temperature and reduced pressure. Two different ethanol-production pathways have been identified for thermophilic bacteria; type I from Clostridium thermocellum, which contains only NADH-linked primary-alcohol dehydrogeneases, and type II from Thermoanaerobacter brockii which in addition include NADPH-linked secondary-alcohol dehydrogenases. The thermophilic anaerobic bacterium T ethanolicus 39E produces ethanol as the major end product from starch, pentose and herose substrates. The 2 Adh has a lower catalytic efficiency for the oxidation of 1 alcohols, including ethanol, than for the oxidation of secondary (2) alcohols or the reduction of ketones or aldehydes and possesses a significant acetyl-CoA reductive thioesterase activity. Large single crystals (0.7 x 0.3 x 0.3 mn) of this enzyme have been obtained at 400C and diffraction data to 2.7 A resolution has been collected (Rmerge = 10.44%). Attempts are currently underway to obtain higher resolution data and a search for heavy atom derivatives is currently underway. The crystals belong to the space group P21 21 2 with cell constants of a a= 170.0 A, b=125.7 A and c=80.5 A. The asymmetric unit contains a tetramer as in the case of the crystals of the secondary alcohol dehydrogenase from Thermoanaerobacter brockii with a VM of 2.85 A3/Da. (author)

  4. Preparation of IrO2 nanoparticles with SBA-15 template and its supported Pt nanocomposite as bifunctional oxygen catalyst

    Science.gov (United States)

    Kong, Fan-Dong; Liu, Jing; Ling, Ai-Xia; Xu, Zhi-Qiang; Wang, Hui-Yun; Kong, Qing-Sheng

    2015-12-01

    In the present work, we report the syntheses of IrO2 nanoparticles with SBA-15 template (s-IrO2), and s-IrO2 supported Pt nanocomposite (Pt/s-IrO2) as bifunctional oxygen catalyst. Physical characterizations including X-ray diffraction and transmission electron microscopy demonstrate that s-IrO2 catalyst has excellent uniformity and regularity in particle shape and much ordered distribution in geometric space, and Pt/s-IrO2 catalyst shows a uniform Pt dispersion on the surface of the s-IrO2 particles. Electrochemical analyses prove that s-IrO2 catalyst possesses superior OER activity at operating potentials; and that Pt/s-IrO2 catalyst, in comparison to Pt/commercial IrO2, has higher ESA value and ORR catalytic performance with a mechanism of four-electron pathway and a high ORR efficiency. And as a bifunctional oxygen catalyst, Pt/s-IrO2 also exhibits more remarkable OER performance than the commercial one. The s-IrO2 nanoparticles will be a promising active component (for OER), and suitable for Pt support (for ORR).

  5. Efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica for biodiesel synthesis by esterification of oleic acid with ethanol.

    Science.gov (United States)

    Yin, Ping; Chen, Wen; Liu, Wei; Chen, Hou; Qu, Rongjun; Liu, Xiguang; Tang, Qinghua; Xu, Qiang

    2013-07-01

    An efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica (SG-T-P-LS) has been successfully developed, and biodiesel production of fatty acid ethyl ester (FAEE) from free fatty acid (FFA) oleic acid with short-chain alcohol ethanol catalyzed by SG-T-P-LS was investigated. The process optimization using response surface methodology (RSM) was performed and the interactions between the operational variables were elucidated, and it was found that the molar ratio of alcohol to acid was the most significant factor. The optimum values for maximum conversion ratio can be obtained by using a Box-Behnken center-united design, and the conversion ratio could reach 89.94 ± 0.42% under the conditions that ethanol/acid molar ratio was 1.05:1 and SG-T-P-LS to FFA weight ratio was 14.9 wt.% at 28.6°C. The research results show that SG-T-P and LS-20 could work cooperatively to promote the esterification reaction, and the bifunctional catalyst SG-T-P-LS is a potential catalyst for biodiesel production. PMID:23688666

  6. Synthesis and Characterization of Bifunctional Organic-Glasses Based on Diphenylhydrazone and Barbituric Acid Derivative for Photorefractive Application

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ki Hong [KIST, Seoul (Korea, Republic of); Lee, Sang Ho; Choi, Chil Sung; Kim, Nak Joong [Hanyang University, Seoul (Korea, Republic of); Choi, Dong Hoon [Kyunghee University, Youngin (Korea, Republic of)

    2003-12-15

    A series of amorphous molecules that possess both photoconductive and electro-optic properties was synthesized in order to investigate photorefractive properties of bifunctional organic-glasses. Diethylaminobenzaldehyde- diphenylhydrazone was covalently attached to 5-(4-diethylamino-benzylidene)-1,3-dimethylpyrimidine- 2,4,6-trione through a flexible alkyl chain (3, 4, 5, 6 and 10 carbons) containing two ether linkages. The longer linkage not only lowered the glass transition temperature (Tg) of the molecules, but also allowed faster orientation of the chromophore. To examine the photorefractive properties, a 50 μm-thick film was prepared from the mixture of a bifunctional molecule, butyl benzyl phthalate, and C{sup 60}. The photoconductivity of this composite was as high as 8.01 x 10{sup -12} S/cm at 60 V/μm, and the maximum diffraction efficiency (ηmax) of 50 μm-thick film was about 5% at 80 V/μm.

  7. Solar extreme events

    CERN Document Server

    Hudson, Hugh S

    2015-01-01

    Solar flares and CMEs have a broad range of magnitudes. This review discusses the possibility of "extreme events," defined as those with magnitudes greater than have been seen in the existing historical record. For most quantitative measures, this direct information does not extend more than a century and a half into the recent past. The magnitude distributions (occurrence frequencies) of solar events (flares/CMEs) typically decrease with the parameter measured or inferred (peak flux, mass, energy etc. Flare radiation fluxes tend to follow a power law slightly flatter than $S^{-2}$, where S represents a peak flux; solar particle events (SPEs) follow a still flatter power law up to a limiting magnitude, and then appear to roll over to a steeper distribution, which may take an exponential form or follow a broken power law. This inference comes from the terrestrial $^{14}$C record and from the depth dependence of various radioisotope proxies in the lunar regolith and in meteorites. Recently major new observation...

  8. Extremely Anisotropic Scintillations

    CERN Document Server

    Walker, Mark; Bignall, Hayley

    2008-01-01

    A small number of quasars exhibit interstellar scintillation on time-scales less than an hour; their scintillation patterns are all known to be anisotropic. Here we consider a totally anisotropic model in which the scintillation pattern is effectively one-dimensional. For the persistent rapid scintillators J1819+3845 and PKS1257-326 we show that this model offers a good description of the two-station time-delay measurements and the annual cycle in the scintillation time-scale. Generalising the model to finite anisotropy yields a better match to the data but the improvement is not significant and the two additional parameters which are required to describe this model are not justified by the existing data. The extreme anisotropy we infer for the scintillation patterns must be attributed to the scattering medium rather than a highly elongated source. For J1819+3845 the totally anisotropic model predicts that the particular radio flux variations seen between mid July and late August should repeat between late Au...

  9. Stacked Extreme Learning Machines.

    Science.gov (United States)

    Zhou, Hongming; Huang, Guang-Bin; Lin, Zhiping; Wang, Han; Soh, Yeng Chai

    2015-09-01

    Extreme learning machine (ELM) has recently attracted many researchers' interest due to its very fast learning speed, good generalization ability, and ease of implementation. It provides a unified solution that can be used directly to solve regression, binary, and multiclass classification problems. In this paper, we propose a stacked ELMs (S-ELMs) that is specially designed for solving large and complex data problems. The S-ELMs divides a single large ELM network into multiple stacked small ELMs which are serially connected. The S-ELMs can approximate a very large ELM network with small memory requirement. To further improve the testing accuracy on big data problems, the ELM autoencoder can be implemented during each iteration of the S-ELMs algorithm. The simulation results show that the S-ELMs even with random hidden nodes can achieve similar testing accuracy to support vector machine (SVM) while having low memory requirements. With the help of ELM autoencoder, the S-ELMs can achieve much better testing accuracy than SVM and slightly better accuracy than deep belief network (DBN) with much faster training speed. PMID:25361517

  10. Detectors in Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Blaj, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carini, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carron, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Haller, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hart, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hasi, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Herrmann, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kenney, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Segal, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tomada, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-06

    Free Electron Lasers opened a new window on imaging the motion of atoms and molecules. At SLAC, FEL experiments are performed at LCLS using 120Hz pulses with 1012 - 1013 photons in 10 femtoseconds (billions of times brighter than the most powerful synchrotrons). This extreme detection environment raises unique challenges, from obvious to surprising. Radiation damage is a constant threat due to accidental exposure to insufficiently attenuated beam, focused beam and formation of ice crystals reflecting the beam onto the detector. Often high power optical lasers are also used (e.g., 25TW), increasing the risk of damage or impeding data acquisition through electromagnetic pulses (EMP). The sample can contaminate the detector surface or even produce shrapnel damage. Some experiments require ultra high vacuum (UHV) with strict design, surface contamination and cooling requirements - also for detectors. The setup is often changed between or during experiments with short turnaround times, risking mechanical and ESD damage, requiring work planning, training of operators and sometimes continuous participation of the LCLS Detector Group in the experiments. The detectors used most often at LCLS are CSPAD cameras for hard x-rays and pnCCDs for soft x-rays.

  11. Forecasting extreme electricity spot prices

    OpenAIRE

    Volodymyr Korniichuk

    2012-01-01

    We propose a model for forecasting extreme electricity prices in real time (high frequency) settings. The unique feature of our model is its ability to forecast electricity price exceedances over very high thresholds, where only a few (if any) observations are available. The model can also be applied for simulating times of occurrence and magnitudes of the extreme prices. We employ a copula with a changing dependence parameter for capturing serial dependence in the extreme prices and the cens...

  12. Likelihood estimators for multivariate extremes

    KAUST Repository

    Huser, Raphael Georges

    2015-11-17

    The main approach to inference for multivariate extremes consists in approximating the joint upper tail of the observations by a parametric family arising in the limit for extreme events. The latter may be expressed in terms of componentwise maxima, high threshold exceedances or point processes, yielding different but related asymptotic characterizations and estimators. The present paper clarifies the connections between the main likelihood estimators, and assesses their practical performance. We investigate their ability to estimate the extremal dependence structure and to predict future extremes, using exact calculations and simulation, in the case of the logistic model.

  13. Electrospinning preparation and properties of magnetic-photoluminescent bifunctional bistrand-aligned composite nanofibers bundles

    International Nuclear Information System (INIS)

    Fe3O4/PVP//Eu(BA)3phen/PVP magnetic-photoluminescent bifunctional bistrand-aligned composite nanofibers bundles based on ferroferric oxide(Fe3O4) nanoparticles and europium complex Eu(BA)3phen (BA = benzoic acid) were fabricated via electrospinning by employing a homemade parallel axial electrospinning setup with the side by side dual spinnerets for the first time. The structures, morphology, and properties of the as-prepared products were investigated in detail by X-ray diffraction, field-emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy (TEM), a fluorescence spectrometer, and a vibrating sample magnetometer. SEM analysis showed the average diameter of the individual-strand fiber of the bistrand-aligned composite nanofibers bundles was 200 ± 25 nm. TEM image demonstrated that Fe3O4 nanoparticles were only dispersed into one strand of the bistrand-aligned composite nanofibers bundles, and the average diameter of Fe3O4 nanoparticles was about 15 nm. Under the excitation of 274 nm ultraviolet light, Fe3O4/PVP//Eu(BA)3phen/PVP bistrand-aligned composite nanofibers bundles exhibited red emissions of predominant peaks at 592 and 616 nm, which were respectively attributed to the 5D0 → 7F1 and 5D0 → 7F2 transitions of Eu3+ ions. The fluorescence intensity of the bistrand-aligned composite nanofibers bundles was higher than that of Fe3O4/Eu(BA)3phen/PVP composite nanofibers, and was decreased with the increase of the amounts of Fe3O4 nanoparticles. The saturation magnetizations of the bistrand-aligned composite nanofibers bundles and the Fe3O4/Eu(BA)3phen/PVP composite nanofibers were about equal when the two nanostructures contained the same mass ratios of Fe3O4 nanoparticles, but the saturation magnetizations of the bistrand-aligned composite nanofibers bundles were increased with the increase of the amounts of Fe3O4 nanoparticles. The new type Fe3O4/PVP//Eu(BA)3phen/PVP bistrand-aligned composite nanofibers

  14. Microwave assisted facile one-pot synthesis of 188Re-complex using a tetrahydroborate exchange resin. A bifunctional chelating agent for radiopharmaceuticals

    International Nuclear Information System (INIS)

    A facile one-pot synthesis of 188Re-complex as a bifunctional chelating agent for the preparation of therapeutic radiopharmaceuticals was accomplished with good labeling yields and radiochemical purity by using a tetrahydroborate exchange resin as a reducing agent for a disulfide ligand as well as the [188Re] perrhenate ion under microwave irradiation. (author)

  15. Structures of dCTP deaminase from Escherichia coli with bound substrate and product: reaction mechanism and determinants of mono- and bifunctionality for a family of enzymes

    DEFF Research Database (Denmark)

    Johansson, Eva; Fanø, Mathias; Bynck, Julie H;

    2005-01-01

    complex with dUTP and Mg(2+), and the mutant enzyme also with the substrate dCTP and Mg(2+). The enzyme is a third member of the family of the structurally related trimeric dUTPases and the bifunctional dCTP deaminase-dUTPase from Methanocaldococcus jannaschii. However, the C-terminal fold is completely...

  16. Melittin-MIL-2 fusion protein as a candidate for cancer immunotherapy

    OpenAIRE

    Liu, Mingjun; Wang, Haitao; Liu, Linjie; Wang, Bin; Sun, Guirong

    2016-01-01

    Background Cytokine fusion protein that modulates the immune response holds great potential for cancer immunotherapy. IL-2 is an effective treatment against advanced cancers. However, the therapeutic efficacy of IL-2 is limited by severe systemic toxicity. Several mutants recombinant IL-2 can increase antitumor activity and minimize systemic toxicity. Melittin is an attractive anticancer candidate because of its wide-spectrum lytic properties. We previously generated a bifunctional fusion pro...

  17. Extreme Environments: Why NASA?

    Science.gov (United States)

    Meyer, M. A.

    2002-12-01

    Life on our planet is the only known example in the universe and so we are relegated to this planet for the study of life. However, life may be a natural consequence of planet formation, and so the study of the origin, evolution, distribution and future of life may be greatly informed by planetary exploration. Astrobiology has adopted several approaches to study life on Earth, for deducing our origins, for determining the likelihood of life elsewhere, and for enabling the search for evidence of past or present life. The first approach has been the Exobiology Program, centered around understanding the origins of life and which supports individual investigator research. Second has been the construction of consortia-type research in which researchers from different disciplines focus on a larger problem. This structure began with NASA Specialized Centers of Research and Training and has grown to include the Astrobiology Institute - a collection of competitively selected groups of researchers attacking problems in Astrobiology as individual teams and as a consolidated Institute. With the formation of an intellectual basis for exploring for life elsewhere, Astrobiology has initiated the competitive research and development program in instrument development (Astrobiology Science and Technology for Instrument Development [ASTID] Program) that would enable future mission instruments for the exploration of planetary bodies in the search for prebiotic chemistry, habitable environments (past or present), biomarkers, and possibly life itself. However, the act of exploring requires robust instrumentation, mobile robotic platforms, efficient operations, and a high level of autonomy. To this end, Astrobiology has started a new research activity that promotes scientifically-driven robotic exploration of extreme environments on Earth that are analogous to suspected habitable environments on other planetary bodies. The program is called Astrobiology Science and Technology for

  18. The influence of protein and energy density in commercial diets on growth, body composition, and nutrient retention of sunshine bass Morone chrysops x Morone saxatilis reared at extreme temperature

    Science.gov (United States)

    Three growth trials were conducted with juvenile sunshine bass reared at temperatures typical of winter or summer pond culture in the Southeastern United States. The trials were designed to determine if there was an advantage to feeding a commercial high-protein/high-fat diet during winter and a lo...

  19. Conversion of β-carotene into astaxanthin : two separate enzymes or a bifunctional hydroxylase-ketolase protein?

    OpenAIRE

    Gudiña Eduardo; Martín Juan F; Barredo José L

    2008-01-01

    Abstract Astaxanthin is a xanthophyll of great interest in animal nutrition and human health. The market prospect in the nutraceutics industries for this health-protective molecule is very promising. Astaxanthin is synthesized by several bacteria, algae and plants from β-carotene by the sequential action of two enzymes: a β-carotene, 3,3'-hydroxylase that introduces an hydroxyl group at the 3 (and 3') positions of each of the two β-ionone rings of β-carotene, and a β-carotene ketolase that in...

  20. Preparation and characteristics of Fe{sub 3}O{sub 4}-YVO{sub 4}:Eu{sup 3+} bifunctional magnetic-luminescent nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Peng Hongxia [School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Liu Guixia, E-mail: liuguixia22@yahoo.com.cn [School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Dong Xiangting; Wang Jinxian; Xu Jia; Yu Wensheng [School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China)

    2011-06-16

    Graphical abstract: Highlights: > Bifunctional magnetic-luminescent nanocomposites with Fe{sub 3}O{sub 4} nanoparticles as the core and YVO{sub 4}:Eu{sup 3+} as the shell. > A cubic spinel structrue of Fe{sub 3}O{sub 4} core and a tetragonal phase of YVO{sub 4} shell were obtained. > The nanocomposites displayed a strong red emission and superparamagnetic behavior at room temperature. - Abstract: A facile direct precipitation method has been developed for the synthesis of bifunctional magnetic-luminescent nanocomposites with Fe{sub 3}O{sub 4} nanoparticles as the core and YVO{sub 4}:Eu{sup 3+} as the shell. Transmission electron microscopy (TEM) images revealed that the obtained bifunctional nanocomposites had a core-shell structure and a spherical morphology. The average size was {approx}150 nm, and the thickness of the shell was {approx}15 nm. The X-ray diffraction (XRD) patterns showed that a cubic spinel structure of Fe{sub 3}O{sub 4} core and a tetragonal phase of YVO{sub 4} shell were obtained. Fourier transform infrared (FT-IR) spectra confirmed that the YVO{sub 4}:Eu{sup 3+} had been successfully deposited on the surface of Fe{sub 3}O{sub 4} nanoparticles. Photoluminescence (PL) spectra indicated that the nanocomposites displayed a strong red characteristic emission of Eu{sup 3+}. Magnetic measurements showed that the obtained bifunctional nanocomposites exhibited superparamagnetic behavior at room temperature. Therefore, the bifunctional nanocomposites are expected to develop many potential applications in biomedical fields.

  1. Denitrification by extremely halophilic bacteria

    Science.gov (United States)

    Hochstein, L. I.; Tomlinson, G. A.

    1985-01-01

    Extremely halophilic bacteria were isolated from widely separated sites by anaerobic enrichment in the presence of nitrate. The anaerobic growth of several of these isolates was accompanied by the production of nitrite, nitrous oxide, and dinitrogen. These results are a direct confirmation of the existence of extremely halophilic denitrifying bacteria, and suggest that such bacteria may be common inhabitants of hypersaline environments.

  2. Gender, Education, Extremism and Security

    Science.gov (United States)

    Davies, Lynn

    2008-01-01

    This paper examines the complex relationships between gender, education, extremism and security. After defining extremism and fundamentalism, it looks first at the relationship of gender to violence generally, before looking specifically at how this plays out in more extremist violence and terrorism. Religious fundamentalism is also shown to have…

  3. Extreme Mean and Its Applications

    Science.gov (United States)

    Swaroop, R.; Brownlow, J. D.

    1979-01-01

    Extreme value statistics obtained from normally distributed data are considered. An extreme mean is defined as the mean of p-th probability truncated normal distribution. An unbiased estimate of this extreme mean and its large sample distribution are derived. The distribution of this estimate even for very large samples is found to be nonnormal. Further, as the sample size increases, the variance of the unbiased estimate converges to the Cramer-Rao lower bound. The computer program used to obtain the density and distribution functions of the standardized unbiased estimate, and the confidence intervals of the extreme mean for any data are included for ready application. An example is included to demonstrate the usefulness of extreme mean application.

  4. Modeling extreme risks in ecology.

    Science.gov (United States)

    Burgman, Mark; Franklin, James; Hayes, Keith R; Hosack, Geoffrey R; Peters, Gareth W; Sisson, Scott A

    2012-11-01

    Extreme risks in ecology are typified by circumstances in which data are sporadic or unavailable, understanding is poor, and decisions are urgently needed. Expert judgments are pervasive and disagreements among experts are commonplace. We outline approaches to evaluating extreme risks in ecology that rely on stochastic simulation, with a particular focus on methods to evaluate the likelihood of extinction and quasi-extinction of threatened species, and the likelihood of establishment and spread of invasive pests. We evaluate the importance of assumptions in these assessments and the potential of some new approaches to account for these uncertainties, including hierarchical estimation procedures and generalized extreme value distributions. We conclude by examining the treatment of consequences in extreme risk analysis in ecology and how expert judgment may better be harnessed to evaluate extreme risks. PMID:22817845

  5. Identification of the C-Terminal GH5 Domain from CbCel9B/Man5A as the First Glycoside Hydrolase with Thermal Activation Property from a Multimodular Bifunctional Enzyme.

    Directory of Open Access Journals (Sweden)

    Rong Wang

    Full Text Available Caldicellulosiruptor bescii encodes at least six unique multimodular glycoside hydrolases crucial for plant cell wall polysaccharides degradation, with each having two catalytic domains separated by two to three carbohydrate binding modules. Among the six enzymes, three have one N- or C-terminal GH5 domain with identical amino acid sequences. Despite a few reports on some of these multimodular enzymes, little is known about how the conserved GH5 domains behave, which are believed to be important due to the gene duplication. We thus cloned a representative GH5 domain from the C-terminus of a multimodular protein, i.e. the bifunctional cellulase/mannanase CbCel9B/Man5A which has been reported, and expressed it in Escherichia coli. Without any appending CBMs, the recombinant CbMan5A was still able to hydrolyze a variety of mannan substrates with different backbone linkages or side-chain decorations. While CbMan5A displayed the same pH optimum as CbCel9B/Man5A, it had an increased optimal temperature (90°C and moreover, was activated by heating at 70°C and 80°C, a property not ever reported for the full-length protein. The turnover numbers of CbMan5A on mannan substrates were, however, lower than those of CbCel9B/Man5A. These data suggested that evolution of CbMan5A and the other domains into a single polypeptide is not a simple assembly; rather, the behavior of one module may be affected by the other ones in the full-length enzyme. The differential scanning calorimetry analysis further indicated that heating CbMan5A was not a simple transition state process. To the best knowledge of the authors, CbMan5A is the first glycoside hydrolase with thermal activation property identified from a multimodular bifunctional enzyme.

  6. Characterizing extremal coefficient functions and extremal correlation functions

    OpenAIRE

    Strokorb, Kirstin; Schlather, Martin

    2012-01-01

    We focus on two dependency quantities of a max-stable random field $X$ on some space $T$: the extremal coefficient function $\\theta$ which we define on finite sets of $T$ and the extremal correlation function $\\chi(s,t)=\\lim_{x \\uparrow \\infty} \\PP(X_s \\geq x \\mid X_t \\geq x)$. We fully characterize extremal coefficient functions $\\theta$ by a property called complete alternation and construct a corresponding max-stable random field. Simple properties and consequences concerning the convex ge...

  7. Genomics of an extreme psychrophile, Psychromonas ingrahamii

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Monica [Woods Hole Research Center, Woods Hole, MA; Staley, James T. [University of Washington, Seattle; Danchin, Antoine [Universite Louis Pasteur, France; Wang, T. [University of Washington; Brettin, Tom [Los Alamos National Laboratory (LANL); Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Thompson, Linda S [Los Alamos National Laboratory (LANL)

    2008-05-01

    Background: The genome sequence of the sea-ice bacterium Psychromonas ingrahamii 37, which grows exponentially at -12C, may reveal features that help to explain how this extreme psychrophile is able to grow at such low temperatures. Determination of the whole genome sequence allows comparison with genes of other psychrophiles and mesophiles. Results: Correspondence analysis of the composition of all P. ingrahamii proteins showed that (1) there are 6 classes of proteins, at least one more than other bacteria, (2) integral inner membrane proteins are not sharply separated from bulk proteins suggesting that, overall, they may have a lower hydrophobic character, and (3) there is strong opposition between asparagine and the oxygen-sensitive amino acids methionine, arginine, cysteine and histidine and (4) one of the previously unseen clusters of proteins has a high proportion of "orphan" hypothetical proteins, raising the possibility these are cold-specific proteins. Based on annotation of proteins by sequence similarity, (1) P. ingrahamii has a large number (61) of regulators of cyclic GDP, suggesting that this bacterium produces an extracellular polysaccharide that may help sequester water or lower the freezing point in the vicinity of the cell. (2) P. ingrahamii has genes for production of the osmolyte, betaine choline, which may balance the osmotic pressure as sea ice freezes. (3) P. ingrahamii has a large number (11) of three-subunit TRAP systems that may play an important role in the transport of nutrients into the cell at low temperatures. (4) Chaperones and stress proteins may play a critical role in transforming nascent polypeptides into 3-dimensional configurations that permit low temperature growth. (5) Metabolic properties of P. ingrahamii were deduced. Finally, a few small sets of proteins of unknown function which may play a role in psychrophily have been singled out as worthy of future study. Conclusion: The results of this genomic analysis provide a

  8. Genomics of an extreme psychrophile, Psychromonas ingrahamii

    Directory of Open Access Journals (Sweden)

    Hauser Loren J

    2008-05-01

    Full Text Available Abstract Background The genome sequence of the sea-ice bacterium Psychromonas ingrahamii 37, which grows exponentially at -12C, may reveal features that help to explain how this extreme psychrophile is able to grow at such low temperatures. Determination of the whole genome sequence allows comparison with genes of other psychrophiles and mesophiles. Results Correspondence analysis of the composition of all P. ingrahamii proteins showed that (1 there are 6 classes of proteins, at least one more than other bacteria, (2 integral inner membrane proteins are not sharply separated from bulk proteins suggesting that, overall, they may have a lower hydrophobic character, and (3 there is strong opposition between asparagine and the oxygen-sensitive amino acids methionine, arginine, cysteine and histidine and (4 one of the previously unseen clusters of proteins has a high proportion of "orphan" hypothetical proteins, raising the possibility these are cold-specific proteins. Based on annotation of proteins by sequence similarity, (1 P. ingrahamii has a large number (61 of regulators of cyclic GDP, suggesting that this bacterium produces an extracellular polysaccharide that may help sequester water or lower the freezing point in the vicinity of the cell. (2 P. ingrahamii has genes for production of the osmolyte, betaine choline, which may balance the osmotic pressure as sea ice freezes. (3 P. ingrahamii has a large number (11 of three-subunit TRAP systems that may play an important role in the transport of nutrients into the cell at low temperatures. (4 Chaperones and stress proteins may play a critical role in transforming nascent polypeptides into 3-dimensional configurations that permit low temperature growth. (5 Metabolic properties of P. ingrahamii were deduced. Finally, a few small sets of proteins of unknown function which may play a role in psychrophily have been singled out as worthy of future study. Conclusion The results of this genomic analysis

  9. Mycobacterium tuberculosis AtsG (Rv0296c), GlmU (Rv1018c) and SahH (Rv3248c) Proteins Function as the Human IL-8-Binding Effectors and Contribute to Pathogen Entry into Human Neutrophils.

    Science.gov (United States)

    Dziadek, Bozena; Brzostek, Anna; Grzybowski, Marcin; Fol, Marek; Krupa, Agnieszka; Kryczka, Jakub; Plocinski, Przemyslaw; Kurdowska, Anna; Dziadek, Jaroslaw

    2016-01-01

    Mycobacterium tuberculosis is an extremely successful intracellular pathogen that has evolved a broad spectrum of pathogenic mechanisms that enable its manipulation of host defense elements and its survival in the hostile environment inside phagocytes. Cellular influx into the site of mycobacterial entry is mediated by a variety of chemokines, including interleukin-8 (IL-8), and the innate cytokine network is critical for the development of an adaptive immune response and infection control. Using affinity chromatography, liquid chromatography electrospray ionization tandem mass spectrometry and surface plasmon resonance techniques, we identified M. tuberculosis AtsG arylsulphatase, bifunctional glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridyl transferase (GlmU) and S-adenosyl-L-homocysteine hydrolase (SahH) as the pathogen proteins that bind to human IL-8. The interactions of all of the identified proteins (AtsG, GlmU and SahH) with IL-8 were characterized by high binding affinity with KD values of 6.83x10-6 M, 5.24x10-6 M and 7.14x10-10 M, respectively. Furthermore, the construction of Mtb mutant strains overproducing AtsG, GlmU or SahH allowed determination of the contribution of these proteins to mycobacterial entry into human neutrophils. The significantly increased number of intracellularly located bacilli of the overproducing M. tuberculosis mutant strains compared with those of "wild-type" M. tuberculosis and the binding interaction of AtsG, GlmU and SahH proteins with human IL-8 may indicate that these proteins participate in the modulation of the early events of infection with tubercle bacilli and could affect pathogen attachment to target cells. PMID:26829648

  10. Extreme Value Theory and Statistics of Univariate Extremes: A Review

    OpenAIRE

    Gomes, Maria Ivette; Guillou, Armelle

    2015-01-01

    International audience Statistical issues arising in modelling univariate extremes of a random sample have been successfully used in the most diverse fields, such as biometrics, finance, insurance and risk theory. Statistics of univariate extremes (SUE), the subject to be dealt with in this review paper, has recently faced a huge development, partially because rare events can have catastrophic consequences for human activities, through their impact on the natural and constructed environmen...

  11. The Extreme Right Filter Bubble

    OpenAIRE

    O'Callaghan, Derek; Greene, Derek; Conway, Maura; Carthy, Joe; Cunningham, Pádraig

    2013-01-01

    Due to its status as the most popular video sharing platform, YouTube plays an important role in the online strategy of extreme right groups, where it is often used to host associated content such as music and other propaganda. In this paper, we develop a categorization suitable for the analysis of extreme right channels found on YouTube. By combining this with an NMF-based topic modelling method, we categorize channels originating from links propagated by extreme right Twitter accounts. This...

  12. Higher dimensional extremal black strings

    OpenAIRE

    H. W. Lee; Myung, Y. S.; Kim, Jin Young; Park, D. K.

    1996-01-01

    We investigate the five and six-dimensional black strings within Einstein-Maxwell theory. The extremal black strings are endowed with the null Killing symmetry. We study the propagation of Einstein-Maxwell modes in the extremal black string background by using this symmetry. It turns out that one graviton is a propagating mode, while both the Maxwell $F$ and three-form $H$ fields are non-propagating modes. Further we discuss the stability and classical hair of the extremal black strings.

  13. Nonparametric Spatial Models for Extremes: Application to Extreme Temperature Data.

    Science.gov (United States)

    Fuentes, Montserrat; Henry, John; Reich, Brian

    2013-03-01

    Estimating the probability of extreme temperature events is difficult because of limited records across time and the need to extrapolate the distributions of these events, as opposed to just the mean, to locations where observations are not available. Another related issue is the need to characterize the uncertainty in the estimated probability of extreme events at different locations. Although the tools for statistical modeling of univariate extremes are well-developed, extending these tools to model spatial extreme data is an active area of research. In this paper, in order to make inference about spatial extreme events, we introduce a new nonparametric model for extremes. We present a Dirichlet-based copula model that is a flexible alternative to parametric copula models such as the normal and t-copula. The proposed modelling approach is fitted using a Bayesian framework that allow us to take into account different sources of uncertainty in the data and models. We apply our methods to annual maximum temperature values in the east-south-central United States. PMID:24058280

  14. Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

    Directory of Open Access Journals (Sweden)

    Nico Rublack

    2014-08-01

    Full Text Available Over the past 20 years, the generation of functional RNAs by in vitro selection has become a standard technique. Apart from aptamers for simple binding of defined ligands, also RNAs for catalysis of chemical reactions have been selected. In the latter case, a key step often is the conjugation of one of the two reactants to the library, requiring suitable strategies for terminal or internal RNA functionalization. With the aim of selecting a ribozyme for deamination of cytidine, we have set up a selection scheme involving the attachment of the cytidine acting as deamination substrate to the 3'-terminus of the RNAs in the library, and library immobilization. Here, we report the synthesis of a bifunctional cytidine derivative suitable for conjugation to RNA and linkage of the conjugated library to a streptavidine-coated surface. Successful conjugation of the cytidine derivative to the 3'-terminus of a model RNA is demonstrated.

  15. Identification and Overexpression of a Bifunctional Aldehyde/Alcohol Dehydrogenase Responsible for Ethanol Production in Thermoanaerobacter mathranii

    DEFF Research Database (Denmark)

    Yao, Shuo; Just Mikkelsen, Marie

    2010-01-01

    ethanol as a fermentation product, while other adh knockout strains showed no significant difference from the wild type. Further analysis revealed that the ΔadhE strain was defective in aldehyde dehydrogenase activity, but still maintained alcohol dehydrogenase activity. This showed that AdhE is the major......Thermoanaerobacter mathranii contains four genes, adhA, adhB, bdhA and adhE, predicted to code for alcohol dehydrogenases involved in ethanol metabolism. These alcohol dehydrogenases were characterized as NADP(H)-dependent primary alcohol dehydrogenase (AdhA), secondary alcohol dehydrogenase (Adh......B), butanol dehydrogenase (BdhA) and NAD(H)-dependent bifunctional aldehyde/alcohol dehydrogenase (AdhE), respectively. Here we observed that AdhE is an important enzyme responsible for ethanol production in T. mathranii based on the constructed adh knockout strains. An adhE knockout strain fails to produce...

  16. The EpsE flagellar clutch is bifunctional and synergizes with EPS biosynthesis to promote Bacillus subtilis biofilm formation.

    Directory of Open Access Journals (Sweden)

    Sarah B Guttenplan

    Full Text Available Many bacteria inhibit motility concomitant with the synthesis of an extracellular polysaccharide matrix and the formation of biofilm aggregates. In Bacillus subtilis biofilms, motility is inhibited by EpsE, which acts as a clutch on the flagella rotor to inhibit motility, and which is encoded within the 15 gene eps operon required for EPS production. EpsE shows sequence similarity to the glycosyltransferase family of enzymes, and we demonstrate that the conserved active site motif is required for EPS biosynthesis. We also screen for residues specifically required for either clutch or enzymatic activity and demonstrate that the two functions are genetically separable. Finally, we show that, whereas EPS synthesis activity is dominant for biofilm formation, both functions of EpsE synergize to stabilize cell aggregates and relieve selective pressure to abolish motility by genetic mutation. Thus, the transition from motility to biofilm formation may be governed by a single bifunctional enzyme.

  17. Nonlinearity of the Bifunctional of the Nonadditive Kinetic Energy: Numerical Consequences in Orbital-Free Embedding Calculations

    OpenAIRE

    Dulak, Marcin; Wesolowski, Tomasz Adam

    2006-01-01

    The bifunctional of the nonadditive kinetic energy in the reference system of noninteracting electrons ( [ρA, ρB] = Ts[ρA + ρB] − Ts[ρA] − Ts[ρB]) is the key quantity in orbital-free embedding calculations because they hinge on approximations to [ρA,ρB]. Since [ρA,ρB] is not linear in ρA, the associated potential (functional derivative) [ρ,ρB]/δρ|ρ=ρA(r) changes if ρA varies. In this work, for two approximations to [ρA,ρB], which are nonlinear in ρA (gradient-free and gradient-dependent), the...

  18. N-Terminal Modification with Pseudo-Bifunctional PEG-Hexadecane Markedly Improves the Pharmacological Profile of Human Growth Hormone.

    Science.gov (United States)

    Wu, Ling; Ji, Shaoyang; Hu, Tao

    2015-05-01

    Human growth hormone (hGH) has been used to treat children with short stature, renal failure, and Turner's syndrome. However, clinical application of hGH suffers from its short plasma half-life and low bioavailability. PEGylation and albumin binding are two of the most effective approaches to prolong the plasma half-life of hGH. However, the steric shielding effects of polyethylene glycol (PEG) and albumin can drastically decrease the bioactivity of hGH, which is opposite to the increased pharmacokinetics (PK). In the present study, a long-acting hGH with markedly improved pharmacological profile was rationally designed and prepared by N-terminal modification of hGH with pseudo-bifunctional PEG-hexadecane by using PEG (3.5 kDa or 10 kDa) as the linker. PEGylation and albumin binding with hexadecane can increase the hydrodynamic volume and decrease the immunogenicity of hGH, which thereby markedly increases the PK of hGH. Since N-terminus is far from the bioactive domain of hGH, N-terminal modification of hGH can minimize the steric shielding effects on the bioactive domain of hGH. Hexadecane-bound albumin can be slowly released from hGH during the in vivo circulation, which can slowly restore the bioactivity of hGH. Thus, the high bioactivity of PEG-hexadecane modified hGH (hGH-PEG-HD) was synergistically achieved by N-terminal modification with pseudo-bifunctional PEG-hexadecane and slow-release of albumin. The high pharmacodynamics (PD) of hGH-PEG-HD was due to the synergistic effect of the high bioactivity and the overall increased PK. PMID:25849255

  19. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

    2004-01-01

    In order to continue cost-optimisation of modern large wind turbines, it is important to continously increase the knowledge on wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements. the...... consistent, given the inevitabel uncertainties associated with model as well as with the extreme value data analysis. Keywords: Statistical model, extreme wind conditions, statistical analysis, turbulence, wind loading, statistical analysis, turbulence, wind loading, wind shear, wind turbines....

  20. Luminance ratio for extreme shadings

    OpenAIRE

    Kaňka, Jan; Mohelníková, Jitka; Ullmannová, Kateřina; Vychytil, Jaroslav

    2015-01-01

    Luminance ratio k (-) is a photometric magnitude used for daylight calculation metrics. The paper is focused on specification of luminance ratio values and their influence on daylight factor calculations for of extremely shaded outdoor conditions.

  1. Extreme Lateral Interbody Fusion Procedure

    Medline Plus

    Full Text Available ... 32 FERNANDO VALE, MD: Okay, well the few things that I would like to readdress, number one, it's extremely important that we have good fluoroscopy. I mean, good x-rays. We need ...

  2. Extremal spillovers in financial markets

    OpenAIRE

    Straetmans, Stefan

    2000-01-01

    We analyze the interdependency between different financial markets by using multivariate extreme value theory. This permits one to focus on the occurrence of simultaneous financial market crises, whereas standard co-variance analysis is less suitable for studying extreme interdependencies. The analysis builds on the so-called stable tail dependence function which measures the amount of interdependency between the tail probabilities of multiple random variables. The empirical implementation of...

  3. Oesophageal perforation in extreme prematurity

    OpenAIRE

    Jones, Katherine Elizabeth; Wagener, Silke; Willetts, Ian Edward; Lakhoo, Kokila

    2012-01-01

    Management of oesophageal perforation in extremely premature babies is a challenge and carries a high morbidity. The authors report their experience of three separate cases of oesophageal perforation they encountered over the last 18 months in extremely premature neonates. In the first case, the diagnosis of oesophageal perforation was known in an otherwise stable baby who was treated conservatively with a good outcome. In the second and third cases, the patients proceeded to thoracotomy befo...

  4. Experiences with Extreme Monetary Instability

    OpenAIRE

    Dornbusch, Rudiger

    1990-01-01

    In early 1990, Argentina, Brazil, Peru, Yugoslavia and Poland were experiencing extreme instability or, at least, the early stages of stabilization. Other countries, like Bolivia, had already run the course and stabilized or, like Mexico, had avoided the extreme experience and opted for stabilization promptly and decisively. The lessons from these case studies, and from the earlier experiences of the 1920s and 1940s, have still to be drawn. Exactly the same themes come up each time. The paper...

  5. Promising bifunctional chelators for copper 64-PET imaging: practical (64)Cu radiolabeling and high in vitro and in vivo complex stability.

    Science.gov (United States)

    Wu, Ningjie; Kang, Chi Soo; Sin, Inseok; Ren, Siyuan; Liu, Dijie; Ruthengael, Varyanna C; Lewis, Michael R; Chong, Hyun-Soon

    2016-04-01

    Positron emission tomography (PET) using copper-64 is a sensitive and non-invasive imaging technique for diagnosis and staging of cancer. A bifunctional chelator that can present rapid radiolabeling kinetics and high complex stability with (64)Cu is a critical component for targeted PET imaging. Bifunctional chelates 3p-C-NE3TA, 3p-C-NOTA, and 3p-C-DE4TA were evaluated for complexation kinetics and stability with (64)Cu in vitro and in vivo. Hexadentate 3p-C-NOTA and heptadentate 3p-C-NE3TA possess a smaller TACN-based macrocyclic backbone, while nonadentate 3p-C-DE4TA is constructed on a larger CYCLEN-based ring. The frequently explored chelates of (64)Cu, octadentate C-DOTA and hexadentate C-NOTA were also comparatively evaluated. Radiolabeling kinetics of bifunctional chelators with (64)Cu was assessed under mild conditions. All bifunctional chelates instantly bound to (64)Cu in excellent radiolabeling efficiency at room temperature. C-DOTA was less efficient in binding (64)Cu than all other chelates. All (64)Cu-radiolabeled bifunctional chelates remained stable in human serum without any loss of (64)Cu for 2 days. When challenged by an excess amount of EDTA, (64)Cu complexes of C-NOTA, 3p-C-NE3TA and 3p-C-NOTA were shown to be more stable than (64)Cu-C-DOTA and (64)Cu-3p-C-DE4TA. (64)Cu complexes of the new chelates 3p-C-NE3TA and 3p-C-NOTA displayed comparable in vitro and in vivo complex stability to (64)Cu-C-NOTA. In vivo biodistribution result indicates that the (64)Cu-radiolabeled complexes of 3p-C-NOTA and 3p-C-NE3TA possess excellent in vivo complex stability, while (64)Cu-3p-C-DE4TA was dissociated as evidenced by high renal and liver retention in mice. The results of in vitro and in vivo studies suggest that the bifunctional chelates 3p-C-NE3TA and 3p-C-NOTA offer excellent chelation chemistry with (64)Cu for potential PET imaging applications. PMID:26666778

  6. Extreme resistance to two Brazilian strains of Potato virus Y (PVY in transgenic potato, cv. Achat, expressing the PVYº coat protein Resistência extrema a duas estirpes do Potato virus Y (PVY de batata transgênica, cv. Achat, expressando o gene da capa protéica do PVY O

    Directory of Open Access Journals (Sweden)

    Eduardo Romano

    2001-07-01

    Full Text Available The coat protein (CP gene of the potato virus Y strain "o" (PVY O was introduced into potato, cultivar Achat, via Agrobacterium tumefaciens-mediated transformation. Sixty three putative transgenic lines were challenged against the Brazilian strains PVY-OBR and PVY-NBR. An extremely resistant phenotype, against the two strains, was observed in one line, denominated 1P. No symptoms or positive ELISA results were observed in 16 challenged plants from this line. Another clone, named as 63P, showed a lower level of resistance. Southern blot analysis showed five copies of the CP gene in the extremely resistant line and at least three copies in the other resistant line. The stability of the integrated transgenes in the extreme resistant line was examined during several in vitro multiplications over a period of three years, with no modification in the Southern pattern was observed. The stability of the transgenes, the absence of primary infections and the relatively broad spectrum of resistance suggest that the extremely resistant line obtained in this work can be useful for agricultural purposes.O gene da capa protéica (CP do Potato virus Y estirpe "o", foi introduzido em batata cultivar Achat, via Agrobacterium tumefaciens. Sessenta e três linhas possivelmente transgênicas foram desafiadas com as estirpes brasileiras PVY-OBR e PVY-NBR. Uma linha apresentou extrema resistência às duas estirpes inoculadas, e foi denominado clone 1P. Não foram observados sintomas sistêmicos de infecção e as plantas foram negativas em Elisa. Outra linha, denominada clone 63P, mostrou algum nível de resistência. Análises por Southern blot indicaram a presença de pelo menos cinco cópias do gen CP no clone 1P e pelo menos três cópias no clone 63P. A estabilidade do gene introduzido no clone 1P foi avaliada durante três anos, após várias multiplicações in vitro. Não foram observadas mudanças no padrão do Southern blot. A estabilidade do transgene, na

  7. Characterization and Structure of the Aquifex aeolicus Protein DUF752

    OpenAIRE

    Kitamura, Aya; Nishimoto, Madoka; Sengoku, Toru; Shibata, Rie; Jäger, Gunilla; Björk, Glenn R.; Grosjean, Henri; Yokoyama, Shigeyuki; Bessho, Yoshitaka

    2012-01-01

    Post-transcriptional modifications of the wobble uridine (U34) of tRNAs play a critical role in reading NNA/G codons belonging to split codon boxes. In a subset of Escherichia coli tRNA, this wobble uridine is modified to 5-methylaminomethyluridine (mnm5U34) through sequential enzymatic reactions. Uridine 34 is first converted to 5-carboxymethylaminomethyluridine (cmnm5U34) by the MnmE-MnmG enzyme complex. The cmnm5U34 is further modified to mnm5U by the bifunctional MnmC protein. In the firs...

  8. Mimivirus collagen is modified by bifunctional lysyl hydroxylase and glycosyltransferase enzyme

    OpenAIRE

    Luther, K B; Hülsmeier, A J; Schegg, B; Deuber, S A; D. Raoult; Hennet, T.

    2011-01-01

    Collagens, the most abundant proteins in animals, are modified by hydroxylation of proline and lysine residues and by glycosylation of hydroxylysine. Dedicated prolyl hydroxylase, lysyl hydroxylase, and collagen glycosyltransferase enzymes localized in the endoplasmic reticulum mediate these modifications prior to the formation of the collagen triple helix. Whereas collagen-like proteins have been described in some fungi, bacteria, and viruses, the post-translational machinery modifying colla...

  9. One-Dimensional RuO2/Mn2O3 Hollow Architectures as Efficient Bifunctional Catalysts for Lithium-Oxygen Batteries.

    Science.gov (United States)

    Yoon, Ki Ro; Lee, Gil Yong; Jung, Ji-Won; Kim, Nam-Hoon; Kim, Sang Ouk; Kim, Il-Doo

    2016-03-01

    Rational design and massive production of bifunctional catalysts with fast oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics are critical to the realization of highly efficient lithium-oxygen (Li-O2) batteries. Here, we first exploit two types of double-walled RuO2 and Mn2O3 composite fibers, i.e., (i) phase separated RuO2/Mn2O3 fiber-in-tube (RM-FIT) and (ii) multicomposite RuO2/Mn2O3 tube-in-tube (RM-TIT), by controlling ramping rate during electrospinning process. Both RM-FIT and RM-TIT exhibited excellent bifunctional electrocatalytic activities in alkaline media. The air electrodes using RM-FIT and RM-TIT showed enhanced overpotential characteristics and stable cyclability over 100 cycles in the Li-O2 cells, demonstrating high potential as efficient OER and ORR catalysts. PMID:26821307

  10. Study of application properties of novel trisazo hetero bi-functional reactive dyes based on j-acid derivatives for cotton

    International Nuclear Information System (INIS)

    Three novel trisazo hetero bi-functional reactive dyes based on J-acid derivatives were prepared using the diazonium salt of [4-(4-sulphophenylazo-)-2,5-dimethylazobenzene-2-sulphonic acid] and a hetero bi-functional coupling component, derived from 1-hydroxy-6-aminonapthalene-3-sulphonic acid (J-acid), 1-hydroxy-6- methylaminonapthalene-3-sulphonic acid (methyl J-acid), and 1-hydroxy-6-aminonaphthalene-3,5-disulphonic acid (sulpho J-acid). On balance, the dye derived from sulpho J-acid displayed the most attractive set of technical properties, building up and fixing more efficiently than those derived from J-acid and methyl J-acid. In addition, the sulpho J-acid based dye offered better migration and, therefore, level dyeing and ease of wash off. (author)

  11. A bifunctional chromogenic and fluorogenic probe for F{sup −} and Al{sup 3+} based on azo-benzimidazole conjugate

    Energy Technology Data Exchange (ETDEWEB)

    Iniya, Murugan; Jeyanthi, Dharmaraj; Krishnaveni, Karuppiah; Chellappa, Duraisamy, E-mail: dcmku123@gmail.com

    2015-01-15

    A versatile bifunctional probe has been reported for selective individual detection of Al{sup 3+} and F{sup −} through “turn-on” chromogenic and fluorogenic dual modes. The photonic behaviors of probe upon addition of analyte have been determined using UV–vis absorption, fluorescence emission, quantum yield and fluorescence life-time measurement. Density functional theory calculations have been performed to establish the nature of interaction between probe and Al{sup 3+}/F{sup −}. - Highlights: • First report on azo based bifunctional chromogenic and fluorogenic chemosensor for Al{sup 3+} and F{sup −} with varied responses. • The probe displays simple method of synthesis, reversibility towards Al{sup 3+} and high stability. • TD–DFT calculations were performed to characterize the nature of fluorescent behavior of probe upon addition of Al{sup 3+} and F{sup −}.

  12. Direct interaction between the cell division protein FtsZ and the cell differentiation protein SpoIIE

    OpenAIRE

    Lucet, Isabelle; Feucht, Andrea; Yudkin, Michael D.; Errington, Jeffery

    2000-01-01

    SpoIIE is a bifunctional protein with two critical roles in the establishment of cell fate in Bacillus subtilis. First, SpoIIE is needed for the normal formation of the asymmetrically positioned septum that forms early in sporulation and separates the mother cell from the prespore compartment. Secondly, SpoIIE is essential for the activation of the first compartment-specific transcription factor σF in the prespore. After initiation of sporulation, SpoIIE localizes to the potential asymmetric ...

  13. Catalytic Asymmetric Synthesis of Both Enantiomers of 4‑Substituted 1,4-Dihydropyridines with the Use of Bifunctional Thiourea-Ammonium Salts Bearing Different Counterions

    Directory of Open Access Journals (Sweden)

    Kohzo Yoshida

    2010-11-01

    Full Text Available Organoammonium salts composed of a Brønsted acid and an anilinothiourea promoted the Michael addition of β-keto esters and α,β-unsaturated aldehydes in the presence of primary amines to give functionalized 1,4-dihydropyridines enantioselectively. With the use of the different Brønsted acids such as DFA and HBF4 with the same bifunctional thiourea, both enantiomers of 4-substituted 1,4-dihydropyridine were synthesized from the same starting materials.

  14. In-situ X-Ray Absorption Spectroscopy (XAS) Investigation of a Bifunctional Manganese Oxide Catalyst with High Activity for Electrochemical Water Oxidation and Oxygen Reduction

    OpenAIRE

    Gorlin, Yelena; Lassalle-Kaiser, Benedikt; Benck, Jesse D.; Gul, Sheraz; Webb, Samuel M; Yachandra, Vittal K.; Yano, Junko; Jaramillo, Thomas F.

    2013-01-01

    In-situ x-ray absorption spectroscopy (XAS) is a powerful technique that can be applied to electrochemical systems, with the ability to elucidate the chemical nature of electrocatalysts under reaction conditions. In this study, we perform in-situ XAS measurements on a bifunctional manganese oxide (MnOx) catalyst with high electrochemical activity for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Using x-ray absorption near edge structure (XANES) and extended x-r...

  15. Identification of catalytic sites for oxygen reduction and oxygen evolution in N-doped graphene materials: Development of highly efficient metal-free bifunctional electrocatalyst

    OpenAIRE

    Yang, Hong Bin; Miao, Jianwei; Hung, Sung-Fu; Chen, Jiazang; Tao, Hua Bing; Wang, Xizu; Zhang, Liping; Chen, Rong; Gao, Jiajian; Chen, Hao Ming; Dai, Liming; Liu, Bin

    2016-01-01

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are critical to renewable energy conversion and storage technologies. Heteroatom-doped carbon nanomaterials have been reported to be efficient metal-free electrocatalysts for ORR in fuel cells for energy conversion, as well as ORR and OER in metal-air batteries for energy storage. We reported that metal-free three-dimensional (3D) graphene nanoribbon networks (N-GRW) doped with nitrogen exhibited superb bifunctional electroca...

  16. Synthesis, metal complexation and biological evaluation of a novel semi-rigid bifunctional chelating agent for 99mTc labelling

    OpenAIRE

    Le Gal, Julien; Michaud, Sandra; Gressier, Marie; Coulais, Yvon; Benoist, Eric

    2006-01-01

    A novel bifunctional chelating agent bearing an aromatic ring has been synthesised and characterised. This ligand formed well-defined oxorhenium complexes. The analogous 99mTcO-complex was obtained in an excellent yield with high radiochemical purity (>95%). The biodistribution of the 99mTo-complex after intravenous injection studied in normal rats showed that the activity was excreted mainly via renal-urinary pathway indicating its use for labelling peptides with 99mTc.

  17. All-optical OR/NOR Bi-functional logic gate by using cross-gain modulation in semiconductor optical amplifiers

    International Nuclear Information System (INIS)

    An OR/NOR bi-functional all-optical logic gate has been experimentally demonstrated at 10 Gbit/s by using cross-gain modulation (XGM) in only 2 semiconductor optical amplifiers (SOAs). One SOA was used for NOR operation and the other SOA was used for inversion to obtain OR operation. Numerical simulation has also been performed, which coincided well with the experimental results.

  18. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors.

    Science.gov (United States)

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Xu, Xiao-Ying; Zhang, Xiao-Mei; Yuan, Wei-Cheng

    2016-01-01

    For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  19. Extreme hydrological events and security

    Science.gov (United States)

    Kundzewicz, Z. W.; Matczak, P.

    2015-06-01

    Economic losses caused by hydrological extremes - floods and droughts - have been on the rise, worldwide. Hydrological extremes jeopardize human security and cause serious threats to human life and welfare and societal livelihood. Floods and droughts can undermine societies' security, understood as freedom from threat and the ability of societies to maintain their independent identity and their functional integrity against forces of change. Several dimensions of security are reviewed in the context of hydrological extremes. Floods and droughts pose a burden and serious challenges to the state, responsible to sustain economic development, societal and environmental security - the maintenance of ecosystem services, on which a society depends. It is shown that reduction of risk of hydrological disasters improves human security.

  20. A bifunctional Delta12,Delta15-desaturase from Acanthamoeba castellanii directs the synthesis of highly unusual n-1 series unsaturated fatty acids.

    Science.gov (United States)

    Sayanova, Olga; Haslam, Richard; Guschina, Irina; Lloyd, David; Christie, William W; Harwood, John L; Napier, Johnathan A

    2006-12-01

    The free-living soil protozoon Acanthamoeba castellanii synthesizes a range of polyunsaturated fatty acids, the balance of which can be altered by environmental changes. We have isolated and functionally characterized in yeast a microsomal desaturase from A. castellanii, which catalyzes the sequential conversion of C(16) and C(18) Delta9-monounsaturated fatty acids to di- and tri-unsaturated forms. In the case of C(16) substrates, this bifunctional A. castellanii Delta12,Delta15-desaturase generated a highly unusual fatty acid, hexadecatrienoic acid (16:3Delta(9,12,15)(n-1)). The identification of a desaturase, which can catalyze the insertion of a double bond between the terminal two carbons of a fatty acid represents a new addition to desaturase functionality and plasticity. We have also co-expressed in yeast the A. castellanii bifunctional Delta12,Delta15-desaturase with a microsomal Delta6-desaturase, resulting in the synthesis of the highly unsaturated C(16) fatty acid hexadecatetraenoic acid (16:4Delta(6,9,12,15)(n-1)), previously only reported in marine microorganisms. Our work therefore demonstrates the feasibility of the heterologous synthesis of polyunsaturated fatty acids of the n-1 series. The presence of a bifunctional Delta12,Delta15-desaturase in A. castellanii is also considered with reference to the evolution of desaturases and the lineage of this protist. PMID:16950768

  1. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.

    2005-01-01

    In order to continue cost-optimisation of modern large wind turbines, it is important to continuously increase the knowledge of wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... model that, on a statistically consistent basis, describes the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of full-scale measurements recorded with a high sampling rate...

  2. Hygienic diagnosis in extreme conditions

    International Nuclear Information System (INIS)

    Review for book by M.P. Zakharchenko, S.A. Lopatin, G.N. Novozhilov, V.I. Zakharov Hygienic diagnosis in extreme conditions is presented discussing the problem of people health preservation under extreme conditions. Hygienic diagnosis is considered illustrated by cases of hostilities (Afghan War), earthquake response in Armenia (1988) and Chernobyl accident response. Attention is paid to the estimation of radiation doses to people and characteristics of main types of dosimeters. The high scientific level of the book is marked

  3. Extreme Conditions Modeling Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Coe, R. G.; Neary, V. S.; Lawson, M. J.; Yu, Y.; Weber, J.

    2014-07-01

    Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) hosted the Wave Energy Converter (WEC) Extreme Conditions Modeling (ECM) Workshop in Albuquerque, NM on May 13th-14th, 2014. The objective of the workshop was to review the current state of knowledge on how to model WECs in extreme conditions (e.g. hurricanes and other large storms) and to suggest how U.S. Department of Energy (DOE) and national laboratory resources could be used to improve ECM methods for the benefit of the wave energy industry.

  4. Extreme Weather and Natural Disasters

    CERN Document Server

    Healey, Justin

    2012-01-01

    Australia is a vast land in which weather varies significantly in different parts of the continent. Recent extreme weather events in Australia, such as the Queensland floods and Victorian bushfires, are brutal reminders of nature's devastating power. Is global warming increasing the rate of natural disasters? What part do La Niña and El Niño play in the extreme weather cycle? Cyclones, floods, severe storms, bushfires, landslides, earthquakes, tsunamis - what are the natural and man-made causes of these phenomena, how predictable are they, and how prepared are we for the impacts of natural dis

  5. Extreme Networksin L2-tietoturvaominaisuudet

    OpenAIRE

    Piispanen, Juha

    2012-01-01

    Opinnäytetyö toteutettiin Jyväskylän ammattikorkeakoulun SpiderNet-laboratorioympäristössä. SpiderNet-laboratorio ympäristöä käytetään Jyväskylän ammattikorkeakoulun tietotekniikka-koulutusohjelman opetuksessa, sekä tutkimus- ja kehityshankkeissa. Opinnäytetyön tavoitteena oli toteuttaa SpiderNet-laboratorioympäristöön L2-kytkinympäristö Extreme Networksin laitteilla, jossa testattiin ja todennettiin Extreme Networksin kytkinten tukemia L2-tason tietoturvatekniikoita. Työssä käytössä oli E...

  6. Extreme low temperature tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    George Richard Strimbeck

    2015-10-01

    Full Text Available Woody plants in boreal to arctic environments and high mountains survive prolonged exposure to temperatures below -40˚C and minimum temperatures below -60˚C, and laboratory tests show that many of these species can also survive immersion in liquid nitrogen at -196˚C. Studies of biochemical changes that occur during acclimation, including recent proteomic and metabolomic studies, have identified changes in carbohydrate and compatible solute concentrations, membrane lipid composition, and proteins, notably dehydrins, that may have important roles in survival at extreme low temperature. Consideration of the biophysical mechanisms of membrane stress and strain lead to the following hypotheses for cellular and molecular mechanisms of survival at extreme low temperature: 1. Changes in lipid composition stabilize membranes at temperatures above the lipid phase transition temperature (-20 to 30˚C, preventing phase changes that result in irreversible injury. 2. High concentrations of oligosaccharides promote vitrification or high viscosity in the cytoplasm in freeze-dehydrated cells, which would prevent deleterious interactions between membranes. 3. Dehydrins bind membranes and further promote vitrification or act stearically to prevent membrane-membrane interactions.

  7. Genetic background of extreme violent behavior.

    Science.gov (United States)

    Tiihonen, J; Rautiainen, M-R; Ollila, H M; Repo-Tiihonen, E; Virkkunen, M; Palotie, A; Pietiläinen, O; Kristiansson, K; Joukamaa, M; Lauerma, H; Saarela, J; Tyni, S; Vartiainen, H; Paananen, J; Goldman, D; Paunio, T

    2015-06-01

    In developed countries, the majority of all violent crime is committed by a small group of antisocial recidivistic offenders, but no genes have been shown to contribute to recidivistic violent offending or severe violent behavior, such as homicide. Our results, from two independent cohorts of Finnish prisoners, revealed that a monoamine oxidase A (MAOA) low-activity genotype (contributing to low dopamine turnover rate) as well as the CDH13 gene (coding for neuronal membrane adhesion protein) are associated with extremely violent behavior (at least 10 committed homicides, attempted homicides or batteries). No substantial signal was observed for either MAOA or CDH13 among non-violent offenders, indicating that findings were specific for violent offending, and not largely attributable to substance abuse or antisocial personality disorder. These results indicate both low monoamine metabolism and neuronal membrane dysfunction as plausible factors in the etiology of extreme criminal violent behavior, and imply that at least about 5-10% of all severe violent crime in Finland is attributable to the aforementioned MAOA and CDH13 genotypes. PMID:25349169

  8. Exfoliated Pd/HNb3O8 nanosheet as highly efficient bifunctional catalyst for one-pot cascade reaction

    Science.gov (United States)

    Lee, Nahaeng; Chung, Young-Min

    2016-05-01

    Ultrathin two-dimensional metal oxide nanosheets have drawn attention as potential solid acid catalysts owing to their strong acidity, attributed to the bridged OH groups formed on the nanosheets. In this study, a new class of bifunctional acid-metal catalyst was realized by the deposition of Pd on layered niobium oxide (KNb3O8 and HNb3O8) or its exfoliated nanosheet (Pd/HNb3O8-NS) and applied to one-pot cascade deacetalization and hydrogenation. It was found that the acid strength of the support exerted a large influence not only on the promotion of the first deacetalization step, but also on the acceleration of the subsequent hydrogenation step. Comparative experiments using a series of Pd/HZSM-5 catalysts with different acidities reconfirmed the crucial role of acid strength on hydrogenation. However, the superior catalytic activity of Pd/HNb3O8-NS for hydrogenation compared to that of Pd/HZSM-5 of similar acidity suggests a more efficient ensemble effect of the strong acid sites with the nearby metal sites on the nanosheet surface. Among the catalysts used, Pd/HNb3O8-NS showed the best catalytic performance for one-pot cascade reaction affording the desired product (benzyl alcohol) in approximately 92% yield, which was 7.1 and 1.2 times higher than that of layered Pd/KNb3O8 or Pd/HNb3O8, respectively. The excellent catalytic performance of Pd/HNb3O8-NS may result from the characteristic features of nanosheets: (i) the synergistic cooperation between the bifunctional active sites and (ii) the two-dimensional open surface offering easier access of the reactants to the active sites. Although the use of NaBH4 as hydrogen source was effective in improving the initial reaction performance, the basic nature of NaBH4 adversely resulted in weakening the acid strength of the catalyst, and consequently led to a reduction in catalytic activity.

  9. Spherical nitrogen-doped hollow mesoporous carbon as an efficient bifunctional electrocatalyst for Zn-air batteries

    Science.gov (United States)

    Hadidi, Lida; Davari, Elaheh; Iqbal, Muhammad; Purkait, Tapas K.; Ivey, Douglas G.; Veinot, Jonathan G. C.

    2015-12-01

    Materials based upon porous carbon have gained considerable attention due to their high surface area, electric conductivity, thermal and chemical stability, low density, and availability. These superior properties make them ideal for diverse applications. Doping these carbon nanostructures holds promise of designing the properties of these structures and opening the door to practical applications. Herein, we report the preparation of hollow N-doped mesoporous carbon (HMC) spheres fabricated via polymerization and carbonization of dopamine on a sacrificial spherical SiO2 template that is removed upon hydrofluoric acid etching. The morphology and structural features of these HMCs were evaluated using scanning electron microscopy and transmission electron microscopy and the N-doping (7.1 at%) was confirmed by X-ray photoelectron spectroscopy (XPS). The oxygen reduction/evolution reaction (ORR/OER) performance of N-doped HMC was evaluated using rotating disk electrode (RDE) voltammetry in an alkaline electrolyte. N-doped HMC demonstrated a high ORR onset potential of -0.055 V (vs. Hg/HgO) and excellent stability. The outstanding bifunctional activity was implemented in a practical Zn-air battery (ZAB), which exhibited a small charge-discharge voltage polarization of 0.89 V and high stability over repeated cycling.Materials based upon porous carbon have gained considerable attention due to their high surface area, electric conductivity, thermal and chemical stability, low density, and availability. These superior properties make them ideal for diverse applications. Doping these carbon nanostructures holds promise of designing the properties of these structures and opening the door to practical applications. Herein, we report the preparation of hollow N-doped mesoporous carbon (HMC) spheres fabricated via polymerization and carbonization of dopamine on a sacrificial spherical SiO2 template that is removed upon hydrofluoric acid etching. The morphology and structural

  10. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  11. Applied extreme-value statistics

    Energy Technology Data Exchange (ETDEWEB)

    Kinnison, R.R.

    1983-05-01

    The statistical theory of extreme values is a well established part of theoretical statistics. Unfortunately, it is seldom part of applied statistics and is infrequently a part of statistical curricula except in advanced studies programs. This has resulted in the impression that it is difficult to understand and not of practical value. In recent environmental and pollution literature, several short articles have appeared with the purpose of documenting all that is necessary for the practical application of extreme value theory to field problems (for example, Roberts, 1979). These articles are so concise that only a statistician can recognise all the subtleties and assumptions necessary for the correct use of the material presented. The intent of this text is to expand upon several recent articles, and to provide the necessary statistical background so that the non-statistician scientist can recognize and extreme value problem when it occurs in his work, be confident in handling simple extreme value problems himself, and know when the problem is statistically beyond his capabilities and requires consultation.

  12. Promoting Exit from Violent Extremism

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja

    2013-01-01

    A number of Western countries are currently adding exit programs targeting militant Islamists to their counterterrorism efforts. Drawing on research into voluntary exit from violent extremism, this article identifies themes and issues that seem to cause doubt, leading to exit. It then provides a...

  13. U.S. Monthly Extremes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GIS U.S. Monthly Extremes is a web based product that is extracted from the U.S. COOP Summary of the Month dataset (DSI-3220). This is meteorological data from the...

  14. Angiography of the upper extremity

    International Nuclear Information System (INIS)

    This thesis provides a description of the technical and medical aspects of arteriography of the upper extremity and an extensive analysis of the angiographic anatomy and pathology of 750 selective studies performed in more than 500 patients. A short historical review is provided of angiography as a whole and of arteriography of the hand in particular. The method of percutaneous transfemoral catheterization of the arteries of the upper extremity and particularly the arteries of the hand is considered, discussing the problems the angiographer encounters frequently, describing the angiographic complications which may occur and emphasizing the measures to keep them to a minimum. The use of vasodilators in hand angiography is discussed. A short description of the embryological patterns persisting in the arteries of the arm is included in order to understand the congenital variations of the arteries of the upper extremity. The angiographic patterns and clinical aspects of the most common pathological processes involving the arteries of the upper extremities are presented. Special attention is paid to the correlation between angiography and pathology. (Auth.)

  15. Extremal Higher Spin Black Holes

    CERN Document Server

    Bañados, Máximo; Faraggi, Alberto; Jottar, Juan I

    2015-01-01

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require nor implies the existence of supersymmetry, we exemplify its consequences in the context of sl(3|2) + sl(3|2) Chern-Simons theory. Remarkably, while as usual not all extremal solutions preserve supersymmetries, we find that the higher spin setup allows for non-extremal supersymmetric black hole solutio...

  16. Astrobiology: Life in Extreme Environments

    Science.gov (United States)

    Kaur, Preeti

    2011-01-01

    Astrobiology is the study of the origin, evolution and distribution of life in the universe. It seeks to answer two important scientific questions: how did we get here and are we alone in the universe? Scientists begin by studying life on Earth and its limits. The discovery of extremophiles on Earth capable of surviving extremes encourages the…

  17. Book review: Extreme ocean waves

    Science.gov (United States)

    Geist, Eric L.

    2011-01-01

    ‘‘Extreme Ocean Waves’’ is a collection of ten papers edited by Efim Pelinovsky and Christian Kharif that followed the April 2007 meeting of the General Assembly of the European Geosciences Union. A note on terminology: extreme waves in this volume broadly encompass different types of waves, includ- ing deep-water and shallow-water rogue waves (alternatively termed freak waves), storm surges from cyclones, and internal waves. Other types of waves such as tsunamis or rissaga (meteotsunamis) are not discussed in this volume. It is generally implied that ‘‘extreme’’ has a statistical connotation relative to the average or significant wave height specific to each type of wave. Throughout the book, in fact, the reader will find a combination of theoretical and statistical/ empirical treatment necessary for the complete examination of this subject. In the introduction, the editors underscore the importance of studying extreme waves, documenting several dramatic instances of damaging extreme waves that occurred in 2007. 

  18. Extreme precipitation: Increases all round

    Science.gov (United States)

    Ingram, William

    2016-05-01

    Globally, extreme rainfall is expected to increase with warming, but regional changes over land have been less certain. Now research shows that this intense precipitation has increased across both the wetter and the drier parts of the continents, and will continue to do so as global warming continues.

  19. Extreme Lateral Interbody Fusion Procedure

    Medline Plus

    Full Text Available ... these instruments to be able to perform the surgery. We're not hurting anybody. This is the way that it works in the spine. You have to get access there, you've got to work against bone, which is extremely hard. So it's normal ...

  20. Quorum Sensing in Extreme Environments

    Directory of Open Access Journals (Sweden)

    Brendan P. Burns

    2013-01-01

    Full Text Available Microbial communication, particularly that of quorum sensing, plays an important role in regulating gene expression in a range of organisms. Although this phenomenon has been well studied in relation to, for example, virulence gene regulation, the focus of this article is to review our understanding of the role of microbial communication in extreme environments. Cell signaling regulates many important microbial processes and may play a pivotal role in driving microbial functional diversity and ultimately ecosystem function in extreme environments. Several recent studies have characterized cell signaling in modern analogs to early Earth communities (microbial mats, and characterization of cell signaling systems in these communities may provide unique insights in understanding the microbial interactions involved in function and survival in extreme environments. Cell signaling is a fundamental process that may have co-evolved with communities and environmental conditions on the early Earth. Without cell signaling, evolutionary pressures may have even resulted in the extinction rather than evolution of certain microbial groups. One of the biggest challenges in extremophile biology is understanding how and why some microbial functional groups are located where logically they would not be expected to survive, and tightly regulated communication may be key. Finally, quorum sensing has been recently identified for the first time in archaea, and thus communication at multiple levels (potentially even inter-domain may be fundamental in extreme environments.

  1. Extreme value theory in engineering

    CERN Document Server

    Castillo, Enrique

    1988-01-01

    This book is a comprehensive guide to extreme value theory in engineering. Written for the end user with intermediate and advanced statistical knowledge, it covers classical methods as well as recent advances. A collection of 150 examples illustrates the theoretical results and takes the reader from simple applications through complex cases of dependence.

  2. Extreme conditions (p, T, H)

    Energy Technology Data Exchange (ETDEWEB)

    Mesot, J. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The aim of this paper is to summarize the sample environment which will be accessible at the SINQ. In order to illustrate the type of experiments which will be feasible under extreme conditions of temperature, magnetic field and pressure at the SINQ a few selected examples are also given. (author) 7 figs., 14 refs.

  3. Y2O3: Eu3+, Tb3+ spherical particles based anti-reflection and wavelength conversion bi-functional films: Synthesis and application to solar cells

    International Nuclear Information System (INIS)

    Highlights: • Eu3+ and Tb3+ co-doped Y2O3 particles were successfully prepared. The as prepared particles can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. • Y2O3 is not only a good photoluminescence host material, but also it has high corrosion resistivity, thermal stability, and transparency from violet to infrared light. Cooperated with SiO2 sols, it could realize a better anti-reflection property. • As a proof-of-concept application, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO2 AR coating film and 0.55% compared to glass. - Abstract: In this study, Eu3+ and Tb3+ co-doped Y2O3 particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO2 sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application, the as prepared bi-functional films were used to test the standard

  4. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    NARCIS (Netherlands)

    Muszanska, Agnieszka K.; Busscher, Henk J.; Herrmann, Andreas; van der Mei, Henny C.; Norde, Willem

    2011-01-01

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

  5. Extremal higher spin black holes

    Science.gov (United States)

    Bañados, Máximo; Castro, Alejandra; Faraggi, Alberto; Jottar, Juan I.

    2016-04-01

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3 d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require supersymmetry, we exemplify its consequences in the context of sl(3|2) ⊕ sl(3|2) Chern-Simons theory and show that, as usual, not all extremal solutions preserve supersymmetries. Remarkably, we find in addition that the higher spin setup allows for non-extremal supersymmetric black hole solutions. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2) ⊕ sl(3|2) Chern-Simons theory and two-dimensional CFTs with W (3|2) symmetry, the simplest higher spin extension of the N = 2 super-Virasoro algebra. In particular, we compute W (3|2) BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3 d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N = 2 two-dimensional CFTs with extended symmetry algebras.

  6. Performance testing of extremity dosimeters

    International Nuclear Information System (INIS)

    The Health Physics Society Standing Committee (HPSSC) Working Group on Performance Testing of Extremity Dosimeters has issued a draft of a proposed standard for extremity dosimeters. The draft standard proposes methods to be used for testing dosimetry systems that determine occupational radiation dose to the extremities and the performance criterion used to determine compliance. The draft standard has been evaluated by testing the performance of existing processors of extremity dosimeters against the standard's proposed criterion. The proposed performance criterion is: absolute value of B + S ≤ 0.35, where B is the bias (calculated as the average of the performance quotients) of 15 dosimeter measurements and S is the standard deviation of the performance quotients. Dosimeter performance was tested in seven irradiation categories: low-energy photons (general and accident dosimetry), high-energy photons (general and accident dosimetry), beta particles, neutrons, and a mixture category. Twenty-one types of extremity dosimeters (both finger ring and wrist/ankle dosimeters) were received from 11 processors. The dosimeters were irradiated by the Pacific Northwest Laboratory (PNL) to specific dose levels in one or more of the seven categories as specified in the draft standard and were returned to the processors. The processors evaluated the doses and returned the results to PNL for analysis. The results were evaluated against the performance criterion specified in the draft standard. The results indicate that approximately 60% of both the finger ring and the wrist/ankle dosimeters met the performance criterion. Two-thirds of the dosimeters that did not meet the performance criterion had large biases (ranging from 0.25 to 0.80) but small standard deviations (less than 0.15). 21 refs., 3 figs., 20 tabs

  7. Climate Networks and Extreme Events

    Science.gov (United States)

    Kurths, J.

    2014-12-01

    We analyse some climate dynamics from a complex network approach. This leads to an inverse problem: Is there a backbone-like structure underlying the climate system? For this we propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system. This approach enables us to uncover relations to global circulation patterns in oceans and atmosphere. The global scale view on climate networks offers promising new perspectives for detecting dynamical structures based on nonlinear physical processes in the climate system. Moreover, we evaluate different regional climate models from this aspect. This concept is also applied to Monsoon data in order to characterize the regional occurrence of extreme rain events and its impact on predictability. Changing climatic conditions have led to a significant increase in magnitude and frequency of spatially extensive extreme rainfall events in the eastern Central Andes of South America. These events impose substantial natural hazards for population, economy, and ecology by floods and landslides. For example, heavy floods in Bolivia in early 2007 affected more than 133.000 households and produced estimated costs of 443 Mio. USD. Here, we develop a general framework to predict extreme events by combining a non-linear synchronization technique with complex networks. We apply our method to real-time satellite-derived rainfall data and are able to predict a large amount of extreme rainfall events. Our study reveals a linkage between polar and subtropical regimes as responsible mechanism: Extreme rainfall in the eastern Central Andes is caused by the interplay of northward migrating frontal systems and a low-level wind channel from the western Amazon to the subtropics, providing additional moisture. Frontal systems from the Antarctic thus play a key role for sub-seasonal variability of the South American Monsoon System.

  8. Obesity-induced Upper Extremity Lymphedema

    OpenAIRE

    Arin K. Greene, MD, MMSc; Reid A. Maclellan, MD, MMSc

    2013-01-01

    Summary: Obesity increases the risk of upper extremity lymphedema following treatment for breast cancer and can cause lower extremity lymphatic dysfunction in extremely obese individuals. We report the first patient with obesity-induced upper extremity lymphedema. A 62-year-old man with a previous body mass index (BMI) of 105.6, presented with a BMI 60.3 following weight loss. He complained of lymphedema of all 4 extremities, which was confirmed by lymphoscintigraphy. Because the upper limbs ...

  9. Plasmodium AdoMetDC/ODC bifunctional enzyme is essential for male sexual stage development and mosquito transmission.

    Science.gov (United States)

    Hart, Robert J; Ghaffar, Atif; Abdalal, Shaymaa; Perrin, Benjamin; Aly, Ahmed S I

    2016-01-01

    Polyamines are positively-charged organic molecules that are important for cellular growth and division. Polyamines and their synthesizing enzymes are particularly abundant in rapidly proliferating eukaryotic cells such as parasitic protozoa and cancer cells. Polyamine biosynthesis inhibitors, such as Elfornithine, are now being considered for cancer prevention and have been used effectively against Trypanosoma brucei Inhibitors of polyamine biosynthesis have caused growth arrest of Plasmodium falciparum blood stages in vitro, but in P. berghei only partial inhibition has been observed. While polyamine biosynthesis enzymes are characterized and conserved in Plasmodium spp., little is known on the biological roles of these enzymes inside malaria parasite hosts. The bifunctional polyamine biosynthesis enzyme S-adenosyl methionine decarboxylase/ornithine decarboxylase (AdoMetDC/ODC) was targeted for deletion in P. yoelii Deletion of AdoMetDC/ODC significantly reduced blood stage parasitemia but Anopheles transmission was completely blocked. We showed that male gametocytogenesis and male gamete exflagellation were abolished and consequently no ookinetes or oocyst sporozoites could be generated from adometdc/odc(-) parasites. Supplementation of putrescine and spermidine did not rescue the defective phenotypes of male gametocytes and gametes of the knockout parasites. These results highlight the crucial role of polyamine homeostasis in the development and functions of Plasmodium erythrocytic stages in the blood and in the mosquito vector and validate polyamine biosynthesis pathway enzymes as drug targeting candidates for malaria parasite transmission blocking. PMID:27387533

  10. The synthesis and properties of bifunctional and intelligent Fe3O4@titanium oxide core/shell nanoparticles.

    Science.gov (United States)

    Yin, Yichao; Liu, Chenjie; Wang, Baoxiang; Yu, Shoushan; Chen, Kezheng

    2013-05-21

    A simple, one-pot solvothermal method has been demonstrated for the preparation of bifunctional Fe3O4@titanium oxide core/shell nanoparticles. In a typical procedure, tetraalkoxyl titanium Ti(OC4H9)4 and FeCl3 as precursors were added into ethylene glycol and further solvothermal treatment was used to synthesize the core/shell particles. The core/shell particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), SQUID MPMS and rheometry. The morphological results showed titanium oxide nanorods with 100-200 nm length and 10-20 nm diameter coated on the surface of 200-300 nm Fe3O4 submicrospheres. Reaction time, the titanium source, the barium salt etc. have an influence on the morphology of core/shell particles. The core/shell particles can not only respond to an external magnetic field, but also to an electric field--a novel application of electrorheological fluid. PMID:23532087

  11. Hierarchical NiCo2 O4 Hollow Microcuboids as Bifunctional Electrocatalysts for Overall Water-Splitting.

    Science.gov (United States)

    Gao, Xuehui; Zhang, Hongxiu; Li, Quanguo; Yu, Xuegong; Hong, Zhanglian; Zhang, Xingwang; Liang, Chengdu; Lin, Zhan

    2016-05-17

    Bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte may improve the efficiency of overall water splitting. Nickel cobaltite (NiCo2 O4 ) has been considered a promising electrode material for the OER. However, NiCo2 O4 that can be used as an electrocatalyst in HER has not been studied yet. Herein, we report self-assembled hierarchical NiCo2 O4 hollow microcuboids for overall water splitting including both the HER and OER reactions. The NiCo2 O4 electrode shows excellent activity toward overall water splitting, with 10 mA cm(-2) water-splitting current reached by applying just 1.65 V and 20 mA cm(-2) by applying just 1.74 V across the two electrodes. The synthesis of NiCo2 O4 microflowers confirms the importance of structural features for high-performance overall water splitting. PMID:27061909

  12. Comprehensive Study of an Earth-Abundant Bifunctional 3D Electrode for Efficient Water Electrolysis in Alkaline Medium.

    Science.gov (United States)

    Sharifi, Tiva; Gracia-Espino, Eduardo; Jia, Xueen; Sandström, Robin; Wågberg, Thomas

    2015-12-30

    We report efficient electrolysis of both water-splitting half reactions in the same medium by a bifunctional 3D electrode comprising Co3O4 nanospheres nucleated on the surface of nitrogen-doped carbon nanotubes (NCNTs) that in turn are grown on conductive carbon paper (CP). The resulting electrode exhibits high stability and large electrochemical activity for both oxygen and hydrogen evolution reactions (OER and HER). We obtain a current density of 10 mA/cm(2) in 0.1 M KOH solution at overpotentials of only 0.47 and 0.38 V for OER and HER, respectively. Additionally, the experimental observations are understood and supported by analyzing the Co3O4:NCNT and NCNT:CP interfaces by ab initio calculations. Both the experimental and the theoretical studies indicate that firm and well-established interfaces along the electrode play a crucial role on the stability and electrochemical activity for both OER and HER. PMID:26629887

  13. Preparation and characterization of bifunctional oxidative and acidic catalysts Nb2O5/TS-1 for synthesis of diols

    International Nuclear Information System (INIS)

    Bifunctional oxidative and acidic catalyst was prepared by incorporation of titanium ion (Ti4+) and niobic acid in zeolite molecular-sieve. The catalysts being active both in oxidation reactions due to the presence of tetrahedral Ti4+, and acid-catalyzed reactions due to the presence of niobic acid. Nb/TS-1 was prepared by hydrothermal synthesis of TS-1, calcination in air and subsequent impregnation of niobium into TS-1. The sample was characterized by XRD, FTIR, UV-vis DR, TPR and pyridine adsorption techniques. The XRD analysis of Nb/TS-1 revealed that the MFI structure of the TS-1 support was found to be intact upon incorporation of niobium. The infrared spectra showed that the tetrahedral titanium in the TS-1 is still remained after impregnation with niobium while based on the UV-vis DR result, the niobium species are in the octahedral structure. On the basis TPR and infrared of hydroxyl groups results, it is concluded that niobium species interacted with the silanols on the surface of TS-1. Pyridine adsorption study shows both Bronsted and Lewis acid sites are present in Nb/TS-1. The catalytic results in the transformation of 1-octene to 1,2-octanediol through the formation of 1,2-epoxyoctane by using Nb/TS-1 indicate that the production of epoxide and diol was correlated with the presence of oxidative and Bronsted acidic sites in the catalyst

  14. Simultaneous H2 Generation and Biomass Upgrading in Water by an Efficient Noble-Metal-Free Bifunctional Electrocatalyst.

    Science.gov (United States)

    You, Bo; Jiang, Nan; Liu, Xuan; Sun, Yujie

    2016-08-16

    As an environmentally friendly approach to generate H2 , electrocatalytic water splitting has attracted worldwide interest. However, its broad employment has been inhibited by costly catalysts and low energy conversion efficiency, mainly due to the sluggish anodic half reaction, the O2 evolution reaction (OER), whose product O2 is not of significant value. Herein, we report an efficient strategy to replace OER with a thermodynamically more favorable reaction, the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), catalyzed by 3D Ni2 P nanoparticle arrays on nickel foam (Ni2 P NPA/NF). HMF is one of the primary dehydration intermediates of raw biomass and FDCA is of many industrial applications. As a bifunctional electrocatalyst, Ni2 P NPA/NF is not only active for HMF oxidation but also competent for H2 evolution. In fact, a two-electrode electrolyzer employing Ni2 P NPA/NF for simultaneous H2 and FDCA production required a voltage at least 200 mV smaller compared with pure water splitting to achieve the same current density, as well as exhibiting robust stability and nearly unity Faradaic efficiencies. PMID:27417546

  15. Asymmetric Michael Additions of 4-Hydroxycoumarin to β-Nitrostyrenes with Chiral, Bifunctional Hydrogen-Bonding Catalysts.

    Science.gov (United States)

    Wolf, Florian F; Klare, Helge; Goldfuss, Bernd

    2016-03-01

    Enantioselective Michael additions of 4-hydroxycoumarin to β-nitrostyrenes are catalyzed by different chiral, bifunctional hydrogen-bonding catalysts, based on thiourea- and squaramide motifs. The scope of the catalysis is tested by employing a series of substituted β-nitrostyrenes as well as different solvents. The 3,5-bis(trifluoromethyl)phenyl- and quinine-substituted squaramide catalyst is shown to be the most selective catalyst, resulting in 78% yield and 81% ee. Computational analyses of transition structures with different binding modes show that the most favored transition structure exhibits squaramide (NH)2 binding to an oxygen atom of the enolate nucleophile, while the nitroalkene coordinates via hydrogen bonding to the ammonium function of the quinuclidine unit of the catalyst. Hence, the canted directionality of the squaramide (NH)2 motif, favoring one-atom binding, might be decisive for the selectivity of the reaction. The absolute configuration of the major (-)-(R) enantiomer of the product is assigned computationally according to its optical rotation. PMID:26815792

  16. Catalytic Upgrading of 5-Hydroxymethylfurfural to Drop-in Biofuels by Solid Base and Bifunctional Metal-Acid Catalysts.

    Science.gov (United States)

    Bohre, Ashish; Saha, Basudeb; Abu-Omar, Mahdi M

    2015-12-01

    Design and synthesis of effective heterogeneous catalysts for the conversion of biomass intermediates into long chain hydrocarbon precursors and their subsequent deoxygenation to hydrocarbons is a viable strategy for upgrading lignocellulose into distillate range drop-in biofuels. Herein, we report a two-step process for upgrading 5-hydroxymethylfurfural (HMF) to C9 and C11 fuels with high yield and selectivity. The first step involves aldol condensation of HMF and acetone with a water tolerant solid base catalyst, zirconium carbonate (Zr(CO3 )x ), which gave 92 % C9 -aldol product with high selectivity at nearly 100 % HMF conversion. The as-synthesised Zr(CO3 )x was analysed by several analytical methods for elucidating its structural properties. Recyclability studies of Zr(CO3 )x revealed a negligible loss of its activity after five consecutive cycles over 120 h of operation. Isolated aldol product from the first step was hydrodeoxygenated with a bifunctional Pd/Zeolite-β catalyst in ethanol, which showed quantitative conversion of the aldol product to n-nonane and 1-ethoxynonane with 40 and 56 % selectivity, respectively. 1-Ethoxynonane, a low oxygenate diesel range fuel, which we report for the first time in this paper, is believed to form through etherification of the hydroxymethyl group of the aldol product with ethanol followed by opening of the furan ring and hydrodeoxygenation of the ether intermediate. PMID:26549016

  17. Key residues at the riboflavin kinase catalytic site of the bifunctional riboflavin kinase/FMN adenylyltransferase from Corynebacterium ammoniagenes.

    Science.gov (United States)

    Serrano, Ana; Frago, Susana; Herguedas, Beatriz; Martínez-Júlvez, Marta; Velázquez-Campoy, Adrián; Medina, Milagros

    2013-01-01

    Many known prokaryotic organisms depend on a single bifunctional enzyme, encoded by the RibC of RibF gene and named FAD synthetase (FADS), to convert Riboflavin (RF), first into FMN and then into FAD. The reaction occurs through the sequential action of two activities present on a single polypeptide chain where the N-terminus is responsible for the ATP:FMN adenylyltransferase (FMNAT) activity and the C-terminus for the ATP: riboflavin kinase (RFK) activity. Sequence and structural analysis suggest that T208, N210 and E268 at the C-terminus RFK module of Corynebacterium ammoniagenes FADS (CaFADS) might be key during RF phosphorylation. The effect of site-directed mutagenesis on the RFK activity, as well as on substrates and products binding, indicates that T208 and N210 provide the RFK active-site geometry for binding and catalysis, while E268 might be involved in the catalytic step as catalytic base. These data additionally suggest concerted conformational changes at the RFK module of CaFADS during its activity. Mutations at the RFK site also modulate the binding parameters at the FMNAT active site of CaFADS, altering the catalytic efficiency in the transformation of FMN into FAD. This observation supports the hypothesis that the hexameric assembly previously revealed by the crystal structure of CaFADS might play a functional role during catalysis. PMID:22892871

  18. Moving in extreme environments: what's extreme and who decides?

    Science.gov (United States)

    Cotter, James David; Tipton, Michael J

    2014-01-01

    Humans work, rest and play in immensely varied extreme environments. The term 'extreme' typically refers to insufficiency or excess of one or more stressors, such as thermal energy or gravity. Individuals' behavioural and physiological capacity to endure and enjoy such environments varies immensely. Adverse effects of acute exposure to these environments are readily identifiable (e.g. heat stroke or bone fracture), whereas adverse effects of chronic exposure (e.g. stress fractures or osteoporosis) may be as important but much less discernable. Modern societies have increasingly sought to protect people from such stressors and, in that way, minimise their adverse effects. Regulations are thus established, and advice is provided on what is 'acceptable' exposure. Examples include work/rest cycles in the heat, hydration regimes, rates of ascent to and duration of stay at altitude and diving depth. While usually valuable and well intentioned, it is important to realise the breadth and importance of limitations associated with such guidelines. Regulations and advisories leave less room for self-determination, learning and perhaps adaptation. Regulations based on stress (e.g. work/rest cycles relative to WBGT) are more practical but less direct than those based on strain (e.g. core temperature), but even the latter can be substantively limited (e.g. by lack of criterion validation and allowance for behavioural regulation in the research on which they are based). Extreme Physiology & Medicine is publishing a series of reviews aimed at critically examining the issues involved with self- versus regulation-controlled human movement acutely and chronically in extreme environments. These papers, arising from a research symposium in 2013, are about the impact of people engaging in such environments and the effect of rules and guidelines on their safety, enjoyment, autonomy and productivity. The reviews will cover occupational heat stress, sporting heat stress, hydration, diving

  19. The HtrA/DegP family protease MamE is a bifunctional protein with roles in magnetosome protein localization and magnetite biomineralization

    OpenAIRE

    Quinlan, Anna; Murat, Dorothée; Vali, Hojatollah; Komeili, Arash

    2011-01-01

    Magnetotactic bacteria contain nanometer-sized, membrane-bound organelles, called magnetosomes, which are tasked with the biomineralization of small crystals of the iron oxide magnetite allowing the organism to use geomagnetic field lines for navigation. A key player in this process is the HtrA/DegP family protease MamE. In its absence, Magnetospirillum magneticum str AMB-1 is able to form magnetosome membranes but not magnetite crystals, a defect previously linked to the mislocalization of m...

  20. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    OpenAIRE

    Muszanska, Agnieszka K.; Busscher, Henk J.; Herrmann, Andreas; Henny C van der Mei; Norde, Willem

    2011-01-01

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the telechelic groups of the PEO chains. Covalent conjugation of lysozyme proceeded via reductive amination of aldehyde functionalized PEO blocks (CHO-Pluronic) and the amine groups of the lysine resid...

  1. On causality of extreme events

    CERN Document Server

    Zanin, Massimiliano

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect both linear and non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task.

  2. Extreme value theory and applications

    International Nuclear Information System (INIS)

    The purpose of extreme value theory is to describe the random behaviour of the m-th largest or smallest values of a sample under the most general conditions possible; subsequently those results can be used in concrete decision or design problems. As, in general, the underlying distribution function of the sample variables is completely unknown or, if known, depends on unknown parameters, one usually resorts to the use of asymptotic distribution, that is available in a large number of cases. The paper starts by the case of an independent sample (random variables independent and identically distributed), dealing first with the question of exceedances; it is then dealt with the problems of statistical decision for (eventually small) samples of extremes

  3. Living with the extreme demand

    OpenAIRE

    Teppo Eskelinen

    2013-01-01

    Most of the ethical literature on extreme poverty suggests, that some, if not most, of the incomes of the residents of rich countries ought to be donated to the global poor. Yet complying with this ethical demand becomes increasingly more difficult as the changes in lifestyle in the (post)industrial north demand ever more consumption in order to obtain the necessities for survival in such societies. In this article, I will discuss Peter Singer's famous arguments for the ethical duty to donate...

  4. Upper extremity injuries in golf.

    Science.gov (United States)

    Bayes, Matthew C; Wadsworth, L Tyler

    2009-04-01

    Golf is an asymmetric sport with unique patterns of injury depending upon the skill level. Higher handicap players typically experience injuries that result from swing mechanics, whereas lower handicap and professional players have overuse as the major cause of their injuries. The majority of shoulder injuries affecting golfers occur in the nondominant shoulder. Common shoulder injuries include subacromial impingement, rotator cuff pathology, glenohumeral instability, and arthritis involving the acromioclavicular and/or glenohumeral joints. Lead arm elbow pain resulting from lateral epicondylosis (tennis elbow) is the leading upper extremity injury in amateur golfers. Tendon injury is the most common problem seen in the wrist and forearm of the golfer. Rehabilitation emphasizing improvement in core muscle streng is important in the treatment of golf injury. Emerging treatments for tendinopathy include topical nitrates, ultrasound-guided injection of therapeutic substances, and eccentric rehabilitation. There is evidence supporting physiotherapy, and swing modification directed by a teaching professional, for treatment of upper extremity golf injuries. This article focuses on upper extremity injuries in golf, including a discussion of the epidemiology, causes, diagnosis, treatment, and prevention of injuries occurring in the shoulder, elbow, wrist, and hand. PMID:20048492

  5. Moderate and extreme maternal obesity.

    LENUS (Irish Health Repository)

    Abdelmaboud, M O

    2012-05-01

    The aim of this study was to investigate the prevalence of moderate and extreme obesity among an Irish obstetric population over a 10-year period, and to evaluate the obstetric features of such pregnancies. Of 31,869 women delivered during the years 2000-2009, there were 306 women in the study group, including 173 in the moderate or Class 2 obese category (BMI 35-39.9) and 133 in the extreme or Class 3 obese category (BMI > or = 40).The prevalence of obese women with BMI > or = 35 was 9.6 per 1000 (0.96%), with an upward trend observed from 2.1 per 1000 in the year 2000, to 11.8 per 1000 in the year 2009 (P = 0.001). There was an increase in emergency caesarean section (EMCS) risk for primigravida versus multigravid women, within both obese categories (P < 0.001). However, there was no significant difference in EMCS rates observed between Class 2 and Class 3 obese women, when matched for parity. The prevalence of moderate and extreme obesity reported in this population is high, and appears to be increasing. The increased rates of abdominal delivery, and the levels of associated morbidity observed, have serious implications for such women embarking on pregnancy.

  6. Outcomes for extremely premature infants.

    Science.gov (United States)

    Glass, Hannah C; Costarino, Andrew T; Stayer, Stephen A; Brett, Claire M; Cladis, Franklyn; Davis, Peter J

    2015-06-01

    Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for 7 years and is now approximately 11.39%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23 to 24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal estimated date of confinement. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91% and 95% (compared with 85%-89%) avoids excess mortality; however, final analyses of data from these trials have not been published, so definitive recommendations are still pending. The development of neonatal neurocritical intensive care units may improve neurocognitive outcomes in this high-risk group. Long-term follow-up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages.The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, because therapy and supportive care continue to change, the outcomes of extremely low birth weight infants are

  7. A bifunctional organometallic ruthenium drug with multiple modes of inducing apoptosis.

    Science.gov (United States)

    Chatterjee, Soumya; Biondi, Ilaria; Dyson, Paul J; Bhattacharyya, Arindam

    2011-06-01

    The organometallic glutathione S-transferase inhibitor ruthenium(II) (ethacrynic acid-η(6)-benzylamide)(1,3,5-triaza-7-phosphaadamantane) dichloride, termed ethaRAPTA, has been demonstrated to induce apoptosis in the cisplatin-resistant MCF-7 breast cancer cell line. Probing the molecular basis of this activity suggests that the complex triggers multiple pathways toward apoptosis, including those involving endonuclease G, caspases, and c-Jun N-terminal kinase, which could provide a therapy for multi-drug-resistant tumors. Furthermore, the induction of heat shock protein 70 expression enhances selectivity of the complex for tumor cells, reducing the general toxicity. PMID:21437708

  8. A bi-functional xyloglucan galactosyltransferase is an indispensable salt stress tolerance determinant in arabidop

    KAUST Repository

    Li, Wenbo

    2013-07-01

    Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium (rsa). One of these mutants, rsa3-1, is hypersensitive to NaCl and LiCl but not to CsCl or to general osmotic stress. Reactive oxygen species (ROS) over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/ MUR3/KAM1-encoded xylogluscan galactosyltransferase regulates actin microfilament organization (and thereby contributes to endomembrane distribution) and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phalloidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results suggest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS. © 2013 The Author.

  9. Putting Proteins back into Water

    OpenAIRE

    Rios, Paolo De Los; Caldarelli, Guido

    2000-01-01

    We introduce a simplified protein model where the solvent (water) degrees of freedom appear explicitly (although in an extremely simplified fashion). Using this model we are able to recover the thermodynamic phenomenology of proteins over a wide range of temperatures. In particular we describe both the warm and the {\\it cold} protein denaturation within a single framework, while addressing important issues about the structure of model proteins.

  10. Schwannoma of the upper extremity

    International Nuclear Information System (INIS)

    The study was undertaken to review 22 patients with schwannoma in the upper extremity. Fourteen patients noticed some clinical symptoms such as pain, numbness or Tinel's sign, whereas a lump was only manifestation of the tumor in 8 patients. It was not difficult to obtain preoperatively the diagnosis of schwannoma via clinical symptoms and modern imaging modality such as MRI. The average follow-up period after operation was 29 months, and satisfactory results were obtained in all patients without any recurrence of the tumor. Functional disability was never encountered in any patients, although 6 patients had mild neurological deficit, all of which located in the median nerve distribution. (author)

  11. Gravity and Extreme Magnetism SMEX

    Science.gov (United States)

    2012-01-01

    The Gravity and Extreme Magnetism SMEX mission will be the first mission to catalogue the X-ray polarisation of many astrophysical objects including black-holes and pulsars. This first of its kind mission is enabled by the novel use of a time projection chamber as an X-ray polarimeter. The detector has been developed over the last 5 years, with the current effort charged toward a demonstration of it's technical readiness to be at level 6 prior to the preliminary design review. This talk will describe the design GEMS polarimeter and the results to date from the engineering test unit.

  12. Radiocirculography of the lower extremities

    International Nuclear Information System (INIS)

    The thesis describes the determination of the absolute values (ml per min) of blood flow in the extremities. The method is based on model experiments in elastic tubing system and on comparison with intraoperative electromagnetic flow-measurements. An eight-channel radiocirculograph was used for simultaneous measurement of flow in the two art. femoralis comm., the two art. poplitea and the two art. dors. pedis under different pathological conditions and after therapeutic interventions. Experiences and data on 1400 patients are summarized. (L.E.)

  13. Development of a Bifunctional Andrographolide-Based Chemical Probe for Pharmacological Study.

    Science.gov (United States)

    Hsu, Ya-Hsin; Hsu, Yu-Ling; Liu, Sheng-Hung; Liao, Hsin-Chia; Lee, Po-Xuan; Lin, Chao-Hsiung; Lo, Lee-Chiang; Fu, Shu-Ling

    2016-01-01

    Andrographolide (ANDRO) is a lactone diterpenoid compound present in the medicinal plant Andrographis paniculata which is clinically applied for multiple human diseases in Asia and Europe. The pharmacological activities of andrographolide have been widely demonstrated, including anti-inflammation, anti-cancer and hepatoprotection. However, the pharmacological mechanism of andrographolide remains unclear. Therefore, further characterization on the kinetics and molecular targets of andrographolide is essential. In this study, we described the synthesis and characterization of a novel fluorescent andrographolide derivative (ANDRO-NBD). ANDRO-NBD exhibited a comparable anti-cancer spectrum to andrographolide: ANDRO-NBD was cytotoxic to various types of cancer cells and suppressed the migration activity of melanoma cells; ANDRO-NBD treatment induced the cleavage of heat shock protein 90 (Hsp90) and the downregulation of its client oncoproteins, v-Src and Bcr-abl. Notably, ANDRO-NBD showed superior inhibitory effects to andrographolide in all anticancer assays we have performed. In addition, ANDRO-NBD was further used as a fluorescent probe to investigate the uptake kinetics, cellular distribution and molecular targets of andrographolide. Our data revealed that ANDRO-NBD entered cells rapidly and its fluorescent signal could be detected in nucleus, cytoplasm, mitochondria, and lysosome. Moreover, we demonstrated that ANDRO-NBD was covalently bound to several putative target proteins of andrographolide, including NF-κB and hnRNPK. In summary, we developed a fluorescent andrographolide probe with comparable bioactivity to andrographolide, which serves as a powerful tool to explore the pharmacological mechanism of andrographolide. PMID:27035713

  14. Bifunctional Role of the Treponema pallidum Extracellular Matrix Binding Adhesin Tp0751 ▿

    Science.gov (United States)

    Houston, Simon; Hof, Rebecca; Francescutti, Teresa; Hawkes, Aaron; Boulanger, Martin J.; Cameron, Caroline E.

    2011-01-01

    Treponema pallidum, the causative agent of syphilis, is a highly invasive pathogenic spirochete capable of attaching to host cells, invading the tissue barrier, and undergoing rapid widespread dissemination via the circulatory system. The T. pallidum adhesin Tp0751 was previously shown to bind laminin, the most abundant component of the basement membrane, suggesting a role for this adhesin in host tissue colonization and bacterial dissemination. We hypothesized that similar to that of other invasive pathogens, the interaction of T. pallidum with host coagulation proteins, such as fibrinogen, may also be crucial for dissemination via the circulatory system. To test this prediction, we used enzyme-linked immunosorbent assay (ELISA) methodology to demonstrate specific binding of soluble recombinant Tp0751 to human fibrinogen. Click-chemistry-based palmitoylation profiling of heterologously expressed Tp0751 confirmed the presence of a lipid attachment site within this adhesin. Analysis of the Tp0751 primary sequence revealed the presence of a C-terminal putative HEXXH metalloprotease motif, and in vitro degradation assays confirmed that recombinant Tp0751 purified from both insect and Escherichia coli expression systems degrades human fibrinogen and laminin. The proteolytic activity of Tp0751 was abolished by the presence of the metalloprotease inhibitor 1,10-phenanthroline. Further, inductively coupled plasma-mass spectrometry showed that Tp0751 binds zinc and calcium. Collectively, these results indicate that Tp0751 is a zinc-dependent, membrane-associated protease that exhibits metalloprotease-like characteristics. However, site-directed mutagenesis of the HEXXH motif to HQXXH did not abolish the proteolytic activity of Tp0751, indicating that further mutagenesis studies are required to elucidate the critical active site residues associated with this protein. This study represents the first published description of a T. pallidum protease capable of degrading host

  15. Frequently Asked Questions (FAQ) about Extreme Heat

    Science.gov (United States)

    ... of Emergencies Frequently Asked Questions (FAQ) About Extreme Heat Recommend on Facebook Tweet Share Compartir What happens ... body as a result of exposure to extreme heat? People suffer heat-related illness when the body’s ...

  16. Statistical analysis on extreme wave height

    Digital Repository Service at National Institute of Oceanography (India)

    Teena, N.V.; SanilKumar, V.; Sudheesh, K.; Sajeev, R.

    The classical extreme value theory based on generalized extreme value (GEV) distribution and generalized Pareto distribution (GPD) is applied to the wave height estimate based on wave hindcast data covering a period of 31 years for a location...

  17. Cell tracking with gadophrin-2: a bifunctional contrast agent for MR imaging, optical imaging, and fluorescence microscopy

    International Nuclear Information System (INIS)

    The purpose of this study was to assess the feasibility of use of gadophrin-2 to trace intravenously injected human hematopoietic cells in athymic mice, employing magnetic resonance (MR) imaging, optical imaging (OI), and fluorescence microscopy. Mononuclear peripheral blood cells from GCSF-primed patients were labeled with gadophrin-2 (Schering AG, Berlin, Germany), a paramagnetic and fluorescent metalloporphyrin, using established transfection techniques with cationic liposomes. The labeled cells were evaluated in vitro with electron microscopy and inductively coupled plasma atomic emission spectrometry. Then, 1 x 106-3 x 108 labeled cells were injected into 14 nude Balb/c mice and the in vivo cell distribution was evaluated with MR imaging and OI before and 4, 24, and 48 h after intravenous injection (p.i.). Five additional mice served as controls: three mice were untreated controls and two mice were investigated after injection of unlabeled cells. The contrast agent effect was determined quantitatively for MR imaging by calculating signal-to-noise-ratio (SNR) data. After completion of in vivo imaging studies, fluorescence microscopy of excised organs was performed. Intracellular cytoplasmatic uptake of gadophrin-2 was confirmed by electron microscopy. Spectrometry determined an uptake of 31.56 nmol Gd per 106 cells. After intravenous injection, the distribution of gadophrin-2 labeled cells in nude mice could be visualized by MR, OI, and fluorescence microscopy. At 4 h p.i., the transplanted cells mainly distributed to lung, liver, and spleen, and 24 h p.i. they also distributed to the bone marrow. Fluorescence microscopy confirmed the distribution of gadophrin-2 labeled cells to these target organs. Gadophrin-2 is suited as a bifunctional contrast agent for MR imaging, OI, and fluorescence microscopy and may be used to combine the advantages of each individual imaging modality for in vivo tracking of intravenously injected hematopoietic cells. (orig.)

  18. Cell tracking with gadophrin-2: a bifunctional contrast agent for MR imaging, optical imaging, and fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Daldrup-Link, Heike E. [Department of Radiology, UCSF Medical Center, University of California in San Francisco, 513 Parnassus Ave, CA 94143, San Francisco (United States); Rudelius, Martina; Piontek, Guido; Schlegel, Juergen [Institute of Pathology, Technical University, Munich (Germany); Metz, Stephan; Settles, Marcus; Rummeny, Ernst J. [Department of Radiology, Technical University, Munich (Germany); Pichler, Bernd [Department of Biomedical Engineering, University of California Davis, Davis (United States); Heinzmann, Ulrich [National Research Center for Environment and Health, Technical University, Munich (Germany); Oostendorp, Robert A.J. [3. Clinic of Internal Medicine, Laboratory of Stem Cell Physiology, Technical University, Munich (Germany)

    2004-09-01

    The purpose of this study was to assess the feasibility of use of gadophrin-2 to trace intravenously injected human hematopoietic cells in athymic mice, employing magnetic resonance (MR) imaging, optical imaging (OI), and fluorescence microscopy. Mononuclear peripheral blood cells from GCSF-primed patients were labeled with gadophrin-2 (Schering AG, Berlin, Germany), a paramagnetic and fluorescent metalloporphyrin, using established transfection techniques with cationic liposomes. The labeled cells were evaluated in vitro with electron microscopy and inductively coupled plasma atomic emission spectrometry. Then, 1 x 10{sup 6}-3 x 10{sup 8} labeled cells were injected into 14 nude Balb/c mice and the in vivo cell distribution was evaluated with MR imaging and OI before and 4, 24, and 48 h after intravenous injection (p.i.). Five additional mice served as controls: three mice were untreated controls and two mice were investigated after injection of unlabeled cells. The contrast agent effect was determined quantitatively for MR imaging by calculating signal-to-noise-ratio (SNR) data. After completion of in vivo imaging studies, fluorescence microscopy of excised organs was performed. Intracellular cytoplasmatic uptake of gadophrin-2 was confirmed by electron microscopy. Spectrometry determined an uptake of 31.56 nmol Gd per 10{sup 6} cells. After intravenous injection, the distribution of gadophrin-2 labeled cells in nude mice could be visualized by MR, OI, and fluorescence microscopy. At 4 h p.i., the transplanted cells mainly distributed to lung, liver, and spleen, and 24 h p.i. they also distributed to the bone marrow. Fluorescence microscopy confirmed the distribution of gadophrin-2 labeled cells to these target organs. Gadophrin-2 is suited as a bifunctional contrast agent for MR imaging, OI, and fluorescence microscopy and may be used to combine the advantages of each individual imaging modality for in vivo tracking of intravenously injected hematopoietic cells

  19. Removing organic contaminants with bifunctional iron modified rectorite as efficient adsorbent and visible light photo-Fenton catalyst

    International Nuclear Information System (INIS)

    Highlights: ► Rectorite was modified by ultrasonic-assisted ion-exchange and hydrolysis. ► The pillaring increased the layer-to-layer spacing of rectorite. ► The iron-modified rectorite was found to be an excellent adsorbent. ► The iron-modified rectorite showed good visible light photocatalytic ability. ► FeR was highly chemically stable with a wide operating range of pH. - Abstract: Iron-modified rectorite (FeR) was prepared as both adsorbent and catalyst. The iron modification increased layer-to-layer spacing and surface area of rectorite, leading to much increased adsorption of Rhodamine B (RhB) on rectorite. The maximum adsorption capacity of RhB on FeR reached 101 mg g−1 at pH 4.5, being 11 folds of that on the unmodified one. The iron modification also enabled rectorite to have efficient visible light photocatalytic ability. The apparent rate constant for the degradation of RhB (80 μM) at 298 K and pH 4.5 in the presence of H2O2 (6.0 mM) and FeR (0.4 g L−1) was evaluated to be 0.0413 min−1 under visible light and 0.122 min−1 under sunlight, respectively. The analysis with electron spin resonance spin-trapping technique supported that the iron modified rectorite effectively catalyzed the decomposition of H2O2 into hydroxyl radicals. On the basis of the characterization and analysis, the new bifunctional material was well clarified as both adsorbent and photocatalyst in the removing of organic pollutants.

  20. A Novel N-Acetylglutamate Synthase Architecture Revealed by the Crystal Structure of the Bifunctional Enzyme from Maricaulis maris

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M.; Tuchman, Mendel (Maryland); (GWU); (Georgia)

    2012-05-24

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 {angstrom} resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26{sup o} is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients.

  1. CoSe₂ and NiSe₂ Nanocrystals as Superior Bifunctional Catalysts for Electrochemical and Photoelectrochemical Water Splitting.

    Science.gov (United States)

    Kwak, In Hye; Im, Hyung Soon; Jang, Dong Myung; Kim, Young Woon; Park, Kidong; Lim, Young Rok; Cha, Eun Hee; Park, Jeunghee

    2016-03-01

    Catalysts for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) are central to key renewable energy technologies, including fuel cells and water splitting. Despite tremendous effort, the development of low-cost electrode catalysts with high activity remains a great challenge. In this study, we report the synthesis of CoSe2 and NiSe2 nanocrystals (NCs) as excellent bifunctional catalysts for simultaneous generation of H2 and O2 in water-splitting reactions. NiSe2 NCs exhibit superior electrocatalytic efficiency in OER, with a Tafel slope (b) of 38 mV dec(-1) (in 1 M KOH), and HER, with b = 44 mV dec(-1) (in 0.5 M H2SO4). In comparison, CoSe2 NCs are less efficient for OER (b = 50 mV dec(-1)), but more efficient for HER (b = 40 mV dec(-1)). It was found that CoSe2 NCs contained more metallic metal ions than NiSe2, which could be responsible for their improved performance in HER. Robust evidence for surface oxidation suggests that the surface oxide layers are the actual active sites for OER, and that CoSe2 (or NiSe2) under the surface act as good conductive layers. The higher catalytic activity of NiSe2 is attributed to their oxide layers being more active than those of CoSe2. Furthermore, we fabricated a Si-based photoanode by depositing NiSe2 NCs onto an n-type Si nanowire array, which showed efficient photoelectrochemical water oxidation with a low onset potential (0.7 V versus reversible hydrogen electrode) and high durability. The remarkable catalytic activity, low cost, and scalability of NiSe2 make it a promising candidate for practical water-splitting solar cells. PMID:26848805

  2. The role of the methyltransferase domain of bifunctional restriction enzyme RM.BpuSI in cleavage activity.

    Directory of Open Access Journals (Sweden)

    Arthur Sarrade-Loucheur

    Full Text Available Restriction enzyme (REase RM.BpuSI can be described as a Type IIS/C/G REase for its cleavage site outside of the recognition sequence (Type IIS, bifunctional polypeptide possessing both methyltransferase (MTase and endonuclease activities (Type IIC and endonuclease activity stimulated by S-adenosyl-L-methionine (SAM (Type IIG. The stimulatory effect of SAM on cleavage activity presents a major paradox: a co-factor of the MTase activity that renders the substrate unsusceptible to cleavage enhances the cleavage activity. Here we show that the RM.BpuSI MTase activity modifies both cleavage substrate and product only when they are unmethylated. The MTase activity is, however, much lower than that of M1.BpuSI and is thought not to be the major MTase for host DNA protection. SAM and sinefungin (SIN increase the Vmax of the RM.BpuSI cleavage activity with a proportional change in Km, suggesting the presence of an energetically more favorable pathway is taken. We further showed that RM.BpuSI undergoes substantial conformational changes in the presence of Ca(2+, SIN, cleavage substrate and/or product. Distinct conformers are inferred as the pre-cleavage/cleavage state (in the presence of Ca(2+, substrate or both and MTase state (in the presence of SIN and substrate, SIN and product or product alone. Interestingly, RM.BpuSI adopts a unique conformation when only SIN is present. This SIN-bound state is inferred as a branch point for cleavage and MTase activity and an intermediate to an energetically favorable pathway for cleavage, probably through increasing the binding affinity of the substrate to the enzyme under cleavage conditions. Mutation of a SAM-binding residue resulted in altered conformational changes in the presence of substrate or Ca(2+ and eliminated cleavage activity. The present study underscores the role of the MTase domain as facilitator of efficient cleavage activity for RM.BpuSI.

  3. A novel N-acetylglutamate synthase architecture revealed by the crystal structure of the bifunctional enzyme from Maricaulis maris.

    Directory of Open Access Journals (Sweden)

    Dashuang Shi

    Full Text Available Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS, an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K at 2.7 Å resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK domain, which is likely responsible for N-acetylglutamate kinase (NAGK activity and has a putative arginine binding site, and an N-acetyltransferase (NAT domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26° is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients.

  4. A novel N-acetylglutamate synthase architecture revealed by the crystal structure of the bifunctional enzyme from Maricaulis maris.

    Science.gov (United States)

    Shi, Dashuang; Li, Yongdong; Cabrera-Luque, Juan; Jin, Zhongmin; Yu, Xiaolin; Zhao, Gengxiang; Haskins, Nantaporn; Allewell, Norma M; Tuchman, Mendel

    2011-01-01

    Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 Å resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26° is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients. PMID:22174908

  5. Synthesis and characterization of bifunctional transition-metal/silica-alumina catalysts for the chloromethane conversion to hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, J.F. [Universidade Federal de Rio de Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Quimica; Rojas, L.O.A.; Nascimento, J.C. [Universidade Federal de Rio de Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Quimica; Centro de Tecnologias do Gas (CTGAS), Natal, RN (Brazil)], E-mail: leopoldo@ctgas.com.br; Ruiz, J.A.C. [Centro de Tecnologias do Gas (CTGAS), Natal, RN (Brazil); Benachour, M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Engenharia Quimica

    2008-10-15

    In this work bifunctional (metal-acid) catalysts of Fe, Ni, Fe{sub 2}O{sub 3} and NiO over amorphous silica alumina support were characterized (acidity) and evaluated for the conversion of chloromethane in a fixed bed reactor. Temperature program tests TPD (Temperature Programmed Desorption) and TPR (Temperature Programmed Reduction) were performed to characterize the chemisorption sites for the impregnated and unimpregnated support. New adsorption sites were created on the metal supported catalysts. The conversion yield of chloromethane was evaluated for the five materials. The highest conversion conversion (85%) was observed for the unmodified support (SiAl) after 6 of reaction at 860 K and a WHSV (Weight Hourly Space Velocity) of 4,5 h{sup -1}. The best selectivity toward desirable hydrocarbons (C{sup 3}, C{sup 4}) was found for the Fe-SiAl catalyst. C{sup 3} was also found in the products stream when Ni/SiAl and NiO/SiAl catalysts were tested. Ni catalysts were the most favorable to methane production. The catalytic tests showed coke formation in all materials. For the SiAl support the desorption energy of chloromethane, determined by TPD runs, was 101,9 KJ/mol. The metals presented lower desorption energies (75,2 KJ/mol for Ni and 133,4 KJ/mol for Fe) than the oxides (190,1 KJ/mol for Fe{sub 2}O{sub 3} and 322,4 KJ/mol for NiO). (author)

  6. Production of propylene from 1-butene on highly active "bi-functional single active site" catalyst: Tungsten carbene-hydride supported on alumina

    KAUST Repository

    Mazoyer, Etienne

    2011-12-02

    1-Butene is transformed in a continuous flow reactor over tungsten hydrides precursor W-H/Al2O3, 1, giving a promising yield into propylene at 150 °C and different pressures. Tungsten carbene-hydride single active site operates as a "bi-functional catalyst" through 1-butene isomerization on W-hydride and 1-butene/2-butenes cross-metathesis on W-carbene. This active moiety is generated in situ at the initiation steps by insertion of 1-butene on tungsten hydrides precursor W-H/Al2O3, 1 followed by α-H and β-H abstraction. © 2011 American Chemical Society.

  7. Novel bis-silane/TiO2 bifunctional hybrid films for metal corrosion protection both under ultraviolet irradiation and in the dark

    International Nuclear Information System (INIS)

    Novel silane/TiO2 bifunctional hybrid films based on highly protective bis-[triethoxysilylpropyl]-tetrasulfide silane were prepared on stainless steel substrates. With the addition of silane agent, TiO2 particles can be more easily immobilized and better dispersed onto the substrates, leading to significant enhancement of the photocathodic protection to substrates under ultraviolet irradiation. Meanwhile, due to the high protectiveness of the bis-silane matrix, the obtained hybrid films also have a high barrier performance if they are used in the dark

  8. Concerted bifunctionality of the dCTP deaminase-dUTPase from Methanocaldococcus jannaschii: A structural and pre-steady state kinetic analysis

    DEFF Research Database (Denmark)

    Siggaard, Julie; Johansson, Eva; Vognsen, Tina Reinholdt; Helt, Signe Smedegaard; Harris, Pernille; Larsen, Sine; Willemoës, Martin

    2009-01-01

    Two mutant dCTP deaminase-dUTPases from Methanocaldococcus jannaschii were crystallised and the crystal structures were solved: E145A in complex with the substrate analogue alpha,beta-imido-dUTP and E145Q in complex with diphosphate. Both mutant enzymes were defect in the deaminase reaction and had...... nucleotidyl diphosphorylase reaction was observed in the E145A:alpha,beta-imido-dUTP complex and positioned similarly as in the monofunctional trimeric dUTPase. A comparison of the active sites of the bifunctional enzyme and the monofunctional family members, dCTP deaminase and dUTPase, suggests similar...

  9. Electrocatalytic performances of g-C3N4-LaNiO3 composite as bi-functional catalysts for lithium-oxygen batteries

    OpenAIRE

    Yixin Wu; Taohuan Wang; Yidie Zhang; Sen Xin; Xiaojun He; Dawei Zhang; Jianglan Shui

    2016-01-01

    A low cost and non-precious metal composite material g-C3N4-LaNiO3 (CNL) was synthesized as a bifunctional electrocatalyst for the air electrode of lithium-oxygen (Li-O2) batteries. The composition strategy changed the electron structure of LaNiO3 and g-C3N4, ensures high Ni3+/Ni2+ ratio and more absorbed hydroxyl on the surface of CNL that can promote the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The composite catalyst presents higher activities than the individual...

  10. Organosilylated complex [Eu(TTA)₃(Bpy-Si)]: a bifunctional moiety for the engeneering of luminescent silica-based nanoparticles for bioimaging

    OpenAIRE

    Duarte, Adriana P.; Mauline, Léïla; Gressier, Marie; Dexpert-Ghys, Jeannette; Roques, Christine; Caiut, José Maurício A.; Deffune, Elenice; Maia, Danielle C. G.; Carlos, Iracilda Z; Ferreira, Antonio A. P.; Ribeiro, Sidney J.L.; Menu, Marie-Joëlle

    2013-01-01

    A new highly luminescent europium complex with the formula [Eu(TTA)₃(Bpy-Si)], where TTA stands for the thenoyltrifluoroacetone, (C₄H3S)COCH₂COCF₃, chelating ligand and Bpy-Si, Bpy-CH₂NH(CH₂)₃(OEt)₃, is an organosilyldipyridine ligand displaying a triethoxysilyl group as a grafting function has been synthesized and fully characterized. This bifunctional complex has been grafted onto the surface of dense silica nanoparticles (NPs) and on mesoporous silica microparticles as well. The covalent b...

  11. Lower extremity alignment normogram of Turkish population

    OpenAIRE

    Sezen, Sedat; Kuyurtar, Fehmi; ERDOGAN, Murat; Karaoglanoglu, Mustafa

    2004-01-01

    Extremity alignment normogram is useful in planning arthroplasty, osteotomy and treatment of fracture and malunion. The aim of this study is to get a lower extremity alignment normogram of Turkish population. Lower extremity plain radiographs of a hundred healthy volunteer are obtained and 21 parameters are measured in each of them. Results are statistically analyzed. Mechanical factors depending on aging, alters lower extremity alignment normogram parameters in Turkish population. When lower...

  12. Terrorism and Extremism: Approaches to the Study

    OpenAIRE

    Tankenova Laura Kumarovna

    2015-01-01

    This article discusses the scientific research of terrorism and extremism carried out by scientists from Kazakhstan, Russia and some other countries. A variety of approaches and methods used by experts are studied. The theoretical and practical importance of scientific papers dealing with terrorism and extremism is shown. The authors pay particular attention to the conceptual study of terrorism and extremism. It is noted that the concepts of terrorism and extremism are sometimes confused and ...

  13. Medical homicide and extreme negligence.

    Science.gov (United States)

    Duncanson, Emily; Richards, Virginia; Luce, Kasey M; Gill, James R

    2009-03-01

    Deaths that occur during medical care for the treatment of a disease are rarely certified as homicides. Some "medical" deaths, however, have been criminally prosecuted for manslaughter, reckless endangerment, or reckless homicide. We describe 5 deaths due to medical complications that underwent criminal prosecution. Three of the deaths were certified as homicides. Deaths certified as homicides due to the actions (or inactions) of a caregiver occur in 3 circumstances. The first is when the medical caregiver intentionally causes the death of the patient. The second is a death due to treatment by an unlicensed fraud or quack. The final circumstance is due to extreme medical negligence that involves a gross and wanton disregard for the well-being of the patient and is the most controversial in the medical community. The law defines reckless endangerment as the conscious disregard of a known substantial likelihood of injury to the patient. Criminal neglect typically is defined as the failure to provide timely, safe, adequate, and appropriate services, treatment, and/or care to a patient. In instances of extreme medical negligence, a homicide manner of death is appropriate because the fatality is due to the criminal acts (or inactions) of another. It also furthers one of the major goals of the medicolegal death investigation system, which is to safeguard the public health. PMID:19237847

  14. The Extremes of Quasar Variability

    Science.gov (United States)

    Stern, Daniel

    2016-04-01

    Variability is one of the key observational properties of quasars, and it can be used as a probe of their fueling, physics, and evolution. A new generation of synoptic sky surveys, in combination with the novel data analytics tools, offers unprecedented data sets for the studies of quasars in the time domain. I will illustrate this with examples from the Catalina Real-Time Transient Survey (CRTS), which has an open and growing archive of 500 million light curves, including 350,000 spectroscopically confirmed quasars, with the time baselines ranging from 10 minutes to 10 years. I will discuss a new approach to discover quasars using a combination of variability and mid-IR colors from WISE, which results in a catalog of over a million quasar candidates. I will then discuss quasars with extreme, anomolous light curves, including quasars that have gone through extreme brightening events over the past decade with concordant large changes in their spectroscopic properties. I will also discuss a small subset of quasars with periodic light curves which we interpret as a signature of close (milliparsec scale) supermassive black hole (SMBH) binaries.

  15. The aroQ-encoded monofunctional chorismate mutase (CM-F) protein is a periplasmic enzyme in Erwinia herbicola.

    OpenAIRE

    Xia, T.; J. Song; Zhao, G.; Aldrich, H; Jensen, R A

    1993-01-01

    Enteric bacteria possess two species of chorismate mutase which exist as catalytic domains on the amino termini of the bifunctional PheA and TyrA proteins. In addition, some of these organisms possess a third chorismate mutase, CM-F, which exists as a small monofunctional protein. The CM-F gene (denoted aroQ) from Erwinia herbicola was cloned and sequenced for the first time. A strategy for selection by functional complementation in a chorismate mutase-free Escherichia coli background was dev...

  16. Lentivirus-mediated bifunctional cell labeling for in vivo melanoma study.

    Science.gov (United States)

    Day, Chi-Ping; Carter, John; Bonomi, Carrie; Esposito, Dominic; Crise, Bruce; Ortiz-Conde, Betty; Hollingshead, Melinda; Merlino, Glenn

    2009-06-01

    Lentiviral vectors (LVs) are capable of labeling a broad spectrum of cell types, achieving stable expression of transgenes. However, for in vivo studies, the duration of marker gene expression has been highly variable. We have developed a series of LVs harboring different promoters for expressing reporter gene in mouse cells. Long-term culture and colony formation of several LV-labeled mouse melanoma cells showed that promoters derived from mammalian house-keeping genes, especially those encoding RNA polymerase II (Pol2) and ferritin (FerH), provided the highest consistency for reporter expression. For in vivo studies, primary B16BL6 mouse melanoma were infected with LVs whose luciferase-green fluorescence protein fusion gene (Luc/GFP) was driven by either Pol2 or FerH promoters. When transplanted into syngeneic C57BL/6 mice, Luc/GFP-labeled B16BL6 mouse melanoma cells can be monitored by bioluminescence imaging in vivo, and GFP-positive cells can be isolated from the tumors by fluorescence-activated cell sorter. Pol2-Luc/GFP labeling, while lower in activity, was more sustainable than FerH-Luc/GFP labeling in B16BL6 over consecutive passages into mice. We conclude that Pol-2-Luc/GFP labeling allows long-term in vivo monitoring and tumor cell isolation in immunocompetent mouse melanoma models. PMID:19175523

  17. Zipf law: an extreme perspective

    Science.gov (United States)

    Eliazar, Iddo

    2016-04-01

    Extreme value theory (EVT) asserts that the Fréchet law emerges universally from linearly scaled maxima of collections of independent and identically distributed random variables that are positive-valued. Observations of many real-world sizes, e.g. city-sizes, give rise to the Zipf law: if we rank the sizes decreasingly, and plot the log-sizes versus the log-ranks, then an affine line emerges. In this paper we present an EVT approach to the Zipf law. Specifically, we establish that whenever the Fréchet law emerges from the EVT setting, then the Zipf law follows. The EVT generation of the Zipf law, its universality, and its associated phase transition, are analyzed and described in detail.

  18. Reach Envelope of Human Extremities

    Institute of Scientific and Technical Information of China (English)

    YANG Jingzhou(杨景周); ZHANG Yunqing(张云清); CHEN Liping(陈立平); ABDEL-MALEK Karim

    2004-01-01

    Significant attention in recent years has been given to obtain a better understanding of human joint ranges, measurement, and functionality, especially in conjunction with commands issued by the central nervous system. While researchers have studied motor commands needed to drive a limb to follow a path trajectory, various computer algorithms have been reported that provide adequate analysis of limb modeling and motion. This paper uses a rigorous mathematical formulation to model human limbs, understand their reach envelope, delineate barriers therein where a trajectory becomes difficult to control, and help visualize these barriers. Workspaces of a typical forearm with 9 degrees of freedom, a typical finger modeled as a 4- degree-of-freedom system, and a lower extremity with 4 degrees of freedom are discussed. The results show that using the proposed formulation, joint limits play an important role in distinguishing the barriers.

  19. Zipf law: an extreme perspective

    International Nuclear Information System (INIS)

    Extreme value theory (EVT) asserts that the Fréchet law emerges universally from linearly scaled maxima of collections of independent and identically distributed random variables that are positive-valued. Observations of many real-world sizes, e.g. city-sizes, give rise to the Zipf law: if we rank the sizes decreasingly, and plot the log-sizes versus the log-ranks, then an affine line emerges. In this paper we present an EVT approach to the Zipf law. Specifically, we establish that whenever the Fréchet law emerges from the EVT setting, then the Zipf law follows. The EVT generation of the Zipf law, its universality, and its associated phase transition, are analyzed and described in detail. (letter)

  20. Pneumatic tourniquets in extremity surgery.

    LENUS (Irish Health Repository)

    Wakai, A

    2012-02-03

    Pneumatic tourniquets maintain a relatively bloodless field during extremity surgery, minimize blood loss, aid identification of vital structures, and expedite the procedure. However, they may induce an ischemia-reperfusion injury with potentially harmful local and systemic consequences. Modern pneumatic tourniquets are designed with mechanisms to regulate and maintain pressure. Routine maintenance helps ensure that these systems are working properly. The complications of tourniquet use include postoperative swelling, delay of recovery of muscle power, compression neurapraxia, wound hematoma with the potential for infection, vascular injury, tissue necrosis, and compartment syndrome. Systemic complications can also occur. The incidence of complications can be minimized by use of wider tourniquets, careful preoperative patient evaluation, and adherence to accepted principles of tourniquet use.

  1. Chasing extreme blazars with INTEGRAL

    CERN Document Server

    Bassani, Loredana; Landi, R; Malizia, A; Bird, A J; Bazzano, A; Ubertini, P

    2013-01-01

    Within the blazar population, hard X-ray selected objects are of particular interest as they tend to lie at each end of the blazar sequence. In particular, flat spectrum radio quasars located at high redshifts display the most powerful jets, the largest black hole masses and the most luminous accretion disks: their spectral energy distribution has a Compton peak in the sub-MeV region which favours their detection by instruments like INTEGRAL/IBIS and Swift/BAT. These sources are even more extreme than blazars selected in other wavebands, like, for example, the gamma-ray range explored by Fermi. Here we report on a sample of 12 high redshift blazars detected so far by INTEGRAL, including 3 newly identified objects. Some properties of the combined IBIS/BAT sample of high redshift blazars (z>2) are also compared to those of a similar similar sample obtained by Fermi.

  2. Weather extremes could affect agriculture

    Science.gov (United States)

    Balcerak, Ernie

    2012-05-01

    As Earth's climate warms, agricultural producers will need to adapt. Changes, especially increases in extreme events, are already having an impact on food production, according to speakers at a 1 May session on agriculture and food security at the AGU Science Policy Conference. Christopher Field, director of the Department of Global Ecology at the Carnegie Institution for Science of Washington, D. C., pointed out the complex factors that come into play in understanding food security, including spatially varying controls and stresses, incomplete models, and the potential for threshold responses. Factors that are likely to cause problems include increasing population; increasing preference for meat, which needs more land and energy inputs to produce; climate change; and increasing use of agricultural lands for biomass energy.

  3. Carbon tetrachloride under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pravica, Michael, E-mail: pravica@physics.unlv.edu; Sneed, Daniel; Wang, Yonggang; Smith, Quinlan [High Pressure Science and Engineering Center (HiPSEC) and Department of Physics, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4002 (United States); Subrahmanyam, Garimella [Canadian Light Source, Department of Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 2V3 (Canada)

    2014-05-21

    We report on three experiments on carbon tetrachloride subjected to extreme conditions. In the first experiment, Raman spectra of CCl{sub 4} were acquired up to 28 GPa. Evidence was observed for at least two new phases of CCl{sub 4} above 14 GPa (phase VI) and above 22 GPa (phase VII). Decompression of the sample showed no evidence of pressure-induced decomposition. In the second experiment, a synchrotron x-ray diffraction study was performed up to 30 GPa verifying phase V and potential phases above 14 (VI) and 22 GPa (VII), respectively. In the third study, we examined irradiated CCl{sub 4} using synchrotron infrared spectroscopy to reduce fluorescent contamination. Some sort of carbon allotrope appears as a byproduct suggesting the following reaction with hard x-rays: CCl{sub 4}+ hν → C + 2Cl{sub 2}.

  4. Skeletal fluorosis in immobilized extremities.

    Science.gov (United States)

    Rosenquist, J B

    1975-11-01

    The effect of immobilization on skeletal fluorosis was studied in growing rabbits. One hind leg was immobilized by an external fixation device extending below the wrist joint and above the knee joint, the extremity being in a straight position after severance of the sciatic nerve. The animals, aged 7 weeks at the beginning of the experiment, were given 10 mg of fluoride per kg body weight and day during 12 weeks. In the tibiae, development of the skeletal fluorosis was more irregular than that observed in previous studies of normally active animals, being most excessive in the mobile bone. The immobilization effect was most profound in the femora as the cortical thickness and the femur score were significantly higher than those in the mobile femora. It was suggested that an altered muscular activity was the reason for the observed changes. PMID:1189918

  5. Gini characterization of extreme-value statistics

    Science.gov (United States)

    Eliazar, Iddo I.; Sokolov, Igor M.

    2010-11-01

    This paper presents a profound connection between Gini’s index and extreme-value statistics. Gini’s index is a quantitative gauge for the evenness of probability laws defined on the positive half-line, and is the common measure of societal egalitarianism applied in Economics and in the Social Sciences. Extreme-value statistics-namely, the Gumbel, Fréchet and Weibull probability laws-are the only possible asymptotic statistics emerging from the extremes of large ensembles of independent and identically distributed random variables. Extreme-value statistics play a major role-all across Science and Engineering-in the analysis of rare and extreme events. Introducing generalizations of Gini’s index, and exploring an elemental Poissonian structure underlying the extreme-value statistics, we establish in this paper a Gini-based characterization of extreme-value statistics.

  6. Proposal of Enhanced Extreme Programming Model

    Directory of Open Access Journals (Sweden)

    M. Rizwan Jameel Qureshi

    2015-01-01

    Full Text Available Extreme programming is one of the commonly used agile methodologies in software development. It is very responsive to changing requirements even in the late phases of the project. However, quality activities in extreme programming phases are implemented sequentially along with the activities that work on the functional requirements. This reduces the agility to deliver increments continuously and makes an inverse relationship between quality and agility. Due to this relationship, extreme programming does not consume enough time on making extensive documentation and robust design. To overcome these issues, an enhanced extreme programming model is proposed. Enhanced extreme programming introduces parallelism in the activities' execution through putting quality activities into a separate execution line. In this way, the focus on delivering increments quickly is achieved without affecting the quality of the final output. In enhanced extreme programming, the quality concept is extended to include refinement of all phases of classical extreme programming and creating architectural design based on the refined design documents.

  7. Gut Microbiota and Extreme Longevity.

    Science.gov (United States)

    Biagi, Elena; Franceschi, Claudio; Rampelli, Simone; Severgnini, Marco; Ostan, Rita; Turroni, Silvia; Consolandi, Clarissa; Quercia, Sara; Scurti, Maria; Monti, Daniela; Capri, Miriam; Brigidi, Patrizia; Candela, Marco

    2016-06-01

    The study of the extreme limits of human lifespan may allow a better understanding of how human beings can escape, delay, or survive the most frequent age-related causes of morbidity, a peculiarity shown by long-living individuals. Longevity is a complex trait in which genetics, environment, and stochasticity concur to determine the chance to reach 100 or more years of age [1]. Because of its impact on human metabolism and immunology, the gut microbiome has been proposed as a possible determinant of healthy aging [2, 3]. Indeed, the preservation of host-microbes homeostasis can counteract inflammaging [4], intestinal permeability [5], and decline in bone and cognitive health [6, 7]. Aiming at deepening our knowledge on the relationship between the gut microbiota and a long-living host, we provide for the first time the phylogenetic microbiota analysis of semi-supercentenarians, i.e., 105-109 years old, in comparison to adults, elderly, and centenarians, thus reconstructing the longest available human microbiota trajectory along aging. We highlighted the presence of a core microbiota of highly occurring, symbiotic bacterial taxa (mostly belonging to the dominant Ruminococcaceae, Lachnospiraceae, and Bacteroidaceae families), with a cumulative abundance decreasing along with age. Aging is characterized by an increasing abundance of subdominant species, as well as a rearrangement in their co-occurrence network. These features are maintained in longevity and extreme longevity, but peculiarities emerged, especially in semi-supercentenarians, describing changes that, even accommodating opportunistic and allochthonous bacteria, might possibly support health maintenance during aging, such as an enrichment and/or higher prevalence of health-associated groups (e.g., Akkermansia, Bifidobacterium, and Christensenellaceae). PMID:27185560

  8. Neurilemmoma of extremities: MR findings

    International Nuclear Information System (INIS)

    Six patients with twenty histologically proven neurilemmomas of the extremities were studied using magnetic resonance (MR) imaging. The size, number, signal intensity on spin-echo T1WI (TR 500-650ms/TE 14-25ms) and gradient-echo (TR 200-600ms/TE 14-20ms; flip angle 25-30 .deg.) image, enhancement pattern, detectability of nerve of origin, nerve-lesion relationship, and presence of a capsule were analyzed. The masses ranged from 1 to 12cm in longitudinal diameter and originated from the median nerve, ulnar nerve, sciatic nerve, radial nerve, and tibial nerve. All the nerve tracts except for those of 5 lesions, which could not be detected due to their small diameter, were visualized as low intensity tubular structures. All visible nerve tracts were situated along the periphery of the lesion and this finding was considered to be specific for neurilemmona. All neurilemmomas were isointense with the surrounding muscle on spin-echo T1WI and hyperintense on gradient-echo image. After a Gd-DTPA injection, all masses showed moderate or marked enhancement and more prominent inhomogeneity than that on nonenhanced scan. In 19 out of 20 lesions (95%), a low signal intensity capsule surrounding the masses could be seen. Four of the six patients showed multiple masses, which was unusual as neurilemmoma usually arises as a solitary mass. In conclusion, the MR findings, especially the eccentric location of the mass lesion from the nerve of origin and the presence of a capsule, were useful in making a diagnosis of neurilemmoma of the extremity and that multiple neurilemmomas were not uncommon

  9. Neurilemmoma of extremities: MR findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Bum; Suh, Kyung Jin; Kang, Duck Sik [College of Medicine, Kyungbuk National University, Daegu (Korea, Republic of)

    1993-01-15

    Six patients with twenty histologically proven neurilemmomas of the extremities were studied using magnetic resonance (MR) imaging. The size, number, signal intensity on spin-echo T1WI (TR 500-650ms/TE 14-25ms) and gradient-echo (TR 200-600ms/TE 14-20ms; flip angle 25-30 .deg.) image, enhancement pattern, detectability of nerve of origin, nerve-lesion relationship, and presence of a capsule were analyzed. The masses ranged from 1 to 12cm in longitudinal diameter and originated from the median nerve, ulnar nerve, sciatic nerve, radial nerve, and tibial nerve. All the nerve tracts except for those of 5 lesions, which could not be detected due to their small diameter, were visualized as low intensity tubular structures. All visible nerve tracts were situated along the periphery of the lesion and this finding was considered to be specific for neurilemmona. All neurilemmomas were isointense with the surrounding muscle on spin-echo T1WI and hyperintense on gradient-echo image. After a Gd-DTPA injection, all masses showed moderate or marked enhancement and more prominent inhomogeneity than that on nonenhanced scan. In 19 out of 20 lesions (95%), a low signal intensity capsule surrounding the masses could be seen. Four of the six patients showed multiple masses, which was unusual as neurilemmoma usually arises as a solitary mass. In conclusion, the MR findings, especially the eccentric location of the mass lesion from the nerve of origin and the presence of a capsule, were useful in making a diagnosis of neurilemmoma of the extremity and that multiple neurilemmomas were not uncommon.

  10. Nutritional requirements of extremely low birthweight infants.

    Science.gov (United States)

    Hay, W W

    1994-09-01

    Extremely low birthweight (ELBW) infants are unique in many developmental characteristics that determine nutritional requirements, including: low energy reserves (both carbohydrate and fat); higher metabolic rate (intrinsically, due to a higher body content of more metabolically active organs, e.g. brain, heart, liver); higher protein turnover rate (especially when growing); higher glucose needs for energy and brain metabolism; higher lipid needs to match the in utero rate of fat deposition, and for essential fatty acids for brain, neural and vascular development; excessive evaporative rates, and occasionally very high urinary water and solute losses; low rates of gastrointestinal peristalsis; limited production of gut digestive enzymes and growth factors; high incidence of stressful events (e.g. hypoxemia, respiratory distress, sepsis); and abnormal neurological outcome if not fed adequately. Postnatally, ELBW infants do not grow well, or at all, often for weeks. This leads to a virtual "growth deficit", which has unknown consequences (which for the most part are not good) and requires excessive feeding later on to catch up to normal growth rates and body composition. The major future challenge for the nutrition of these infants is to define more accurately their nutritional requirements, particularly in the early postnatal period, in order to feed them more appropriately, to reduce to a minimum the nutritional and growth deficits that they so commonly develop and to prevent neurodevelopmental handicaps that are the result of nutritional deficiencies. PMID:7841630

  11. Michael Addition of Thiols to á,(a)-Unsaturated Carbonyl Compounds Catalyzed by Bifunctional Organocatalysts:Asymmetric Michael Addition and Asymmetric Protonation

    Institute of Scientific and Technical Information of China (English)

    LI Bang-Jing; JIANG Lin; LIU Min; DING Li-Sheng; CHEN Ying-Chun

    2004-01-01

    Recently the hydrogen-bond activated reactions have attracted much attention.1 Takemoto2 reported a highly enantioselective Michael addition of manolate to nitroolefins catalyzed by a bifunctional organocatalyst with tertiary amine and thiourea moiety. As we known,stereoselective conjugate additions of thiols are interesting due to the standpoint of biological and synthetic importance, however, only very limited good results have been obtained except for the works of Shibasaki3, Kanemasa4 and Deng5 et al.In this letter, we report an efficient catalytic asymmetric Michael reactions of thiols to a,a-unsaturated carbonyl compounds promoted by bifunctional organocatalysts. A series of organocatalysts with chiral amine and thiourea structures were designed and synthesized and have been successfully applied in the conjugated additions of thiols to a,a-unsaturated imides and enones.The reactions got quantitative yields and the ee values were up to 84%. It is noteworthy that the a-asymmetric protonation (up to 43% ee) also could be achieved.The Michael addition between aromatic thiols and a,a-unsaturated carbonyl compounds isdescribed as follows:Works to further increase the enantioselectivity is under investigation in our laboratory.

  12. RuO2 nanoparticles decorated MnOOH/C as effective bifunctional electrocatalysts for lithium-air battery cathodes with long-cycling stability

    Science.gov (United States)

    Kim, Gil-Pyo; Lim, Dongwook; Park, Inyeong; Park, Hyelee; Shim, Sang Eun; Baeck, Sung-Hyeon

    2016-08-01

    Manganite (MnOOH) is one of the most effective electrocatalysts for oxygen reduction reaction (ORR), and RuO2 nanoparticles exhibit high activity for oxygen evolution reaction (OER). We herein report a facile means of producing well dispersed RuO2/MnOOH on Ketjen black (RuO2/MnOOH/C) as a bifunctional catalyst for lithium-air (Li-air) batteries. RuO2/MnOOH/C was simply synthesized using a hydrothermal/precipitation based method, and was used as a cathode for a Li-air battery using a Swagelok-type cell. The importance of dispersing active catalysts on a carbon support was clearly demonstrated by textural, charge-discharge voltammetric, and electrochemical impedance spectroscopic (EIS) analyses, comparing results with a catalyst produced by physically mixing RuO2/MnOOH with carbon (RuO2/MnOOH + C). RuO2/MnOOH/C showed low overpotential and stable cycleability up to 170th cycles with 1000 mAh g-1 of charge-discharge capacity, which was attributed to its enhanced active surface area and low charge-transfer resistance. The results obtained suggest that this strategy can be widely applied to bifunctional electrocatalysis, such as secondary batteries and regenerative fuel cell (RFC).

  13. Remarkable red-shift of upconversion luminescence and anti-ferromagnetic coupling in NaLuF4:Yb3+/Tm3+/Gd3+/Sm3+ bifunctional microcrystals

    Institute of Scientific and Technical Information of China (English)

    胡仕刚; 刘云新; 吴笑峰; 唐志军; 李志明; 颜焕元; 陈增辉; 胡盼; 余意

    2016-01-01

    Lanthanide doped bifunctional materials are potentially important for developing multifunctional devices. Here, NaLuF4:Yb3+/Tm3+/Gd3+/Sm3+ optical-magnetic bifunctional microcrystals were successfully synthesized by hydrothermal method, which could emit ~480 nm blue light from the1G4→3H6 electronic transition and ~800 nm infrared light from the3H4→3H6electronic transition of Tm3+ ion, under the excitation of 980 nm infrared light. By doping Sm3+ ion into NaLuF4:Yb3+/Tm3+/Gd3+, the infrared emission peak centered at 800 nm would shift obviously to longer wavelength. This indicated that Sm3+ ion could efficiently tune the energy level gaps of Tm3+ ions in NaLuF4 host which was demonstrated based on the crystal field theory. In addition, these NaLuF4:Yb3+/Tm3+/Gd3+/Sm3+ microcrystals presented unique ferromagnetic property instead of usually reported paramagnetic prop-erty. Importantly, the ferromagnetic property decreased with increasing the concentration of Gd3+ ion. This was in good agreement with Swift’s theoretical investigation that the coexistence of light rare earth (Gd3+) and heavy rare earth (Yb3+/Tm3+) would lead to the anti-ferromagnetic coupling in the sub-lattices.

  14. Two interpenetrating Cu{sup II}/Ni{sup II}-coordinated polymers based on an unsymmetrical bifunctional N/O-tectonic: Syntheses, structures and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong-Liang [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Department of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, Shang Luo University, Shang Luo 726000 (China); Wu, Ya-Pan [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Li, Dong-Sheng, E-mail: lidongsheng1@126.com [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Dong, Wen-Wen [College of Materials & Chemical Engineering, China Three Gorges University, Yichang 443002 (China); Zhou, Chun-Sheng [Department of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, Shang Luo University, Shang Luo 726000 (China)

    2015-03-15

    Two new interpenetrating Cu{sup II}/Ni{sup II} coordination polymers, based on a unsymmetrical bifunctional N/O-tectonic 3-(pyrid-4′-yl)-5-(4″-carbonylphenyl)-1,2,4-triazolyl (H{sub 2}pycz), ([Cu-(Hpycz){sub 2}]·2H{sub 2}O){sub n} (1) and ([Ni(Hpycz){sub 2}]·H{sub 2}O){sub n} (2), have been solvothermally synthesized and structure characterization. Single crystal X-ray analysis indicates that compound 1 shows 2-fold parallel interpenetrated 4{sup 4}-sql layers with the same handedness. The overall structure of 1 is achiral—in each layer of doubly interpenetrating nets, the two individual nets have the opposite handedness to the corresponding nets in the adjoining layers—while 2 features a rare 8-fold interpenetrating 6{sup 6}-dia network that belongs to class IIIa interpenetration. In addition, compounds 1 and 2 both show similar paramagnetic characteristic properties. - Graphical abstract: Two new Cu(II)/Ni(II) coordination polymers present 2D parallel 2-fold interpenetrated 4{sup 4}-sql layers and a rare 3D 8-fold interpenetrating 6{sup 6}-dia network. In addition, magnetic susceptibility measurements show similar paramagnetic characteristic for two complexes. - Highlights: • A new unsymmetrical bifunctional N/O-tectonic as 4-connected spacer. • A 2-fold parallel interpenetrated sql layer with the same handedness. • A rare 8-fold interpenetrating dia network (class IIIa)

  15. Two interpenetrating CuII/NiII-coordinated polymers based on an unsymmetrical bifunctional N/O-tectonic: Syntheses, structures and magnetic properties

    International Nuclear Information System (INIS)

    Two new interpenetrating CuII/NiII coordination polymers, based on a unsymmetrical bifunctional N/O-tectonic 3-(pyrid-4′-yl)-5-(4″-carbonylphenyl)-1,2,4-triazolyl (H2pycz), ([Cu-(Hpycz)2]·2H2O)n (1) and ([Ni(Hpycz)2]·H2O)n (2), have been solvothermally synthesized and structure characterization. Single crystal X-ray analysis indicates that compound 1 shows 2-fold parallel interpenetrated 44-sql layers with the same handedness. The overall structure of 1 is achiral—in each layer of doubly interpenetrating nets, the two individual nets have the opposite handedness to the corresponding nets in the adjoining layers—while 2 features a rare 8-fold interpenetrating 66-dia network that belongs to class IIIa interpenetration. In addition, compounds 1 and 2 both show similar paramagnetic characteristic properties. - Graphical abstract: Two new Cu(II)/Ni(II) coordination polymers present 2D parallel 2-fold interpenetrated 44-sql layers and a rare 3D 8-fold interpenetrating 66-dia network. In addition, magnetic susceptibility measurements show similar paramagnetic characteristic for two complexes. - Highlights: • A new unsymmetrical bifunctional N/O-tectonic as 4-connected spacer. • A 2-fold parallel interpenetrated sql layer with the same handedness. • A rare 8-fold interpenetrating dia network (class IIIa)

  16. Simultaneously optimizing fluorescent and paramagnetic properties of bifunctional NaGdF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanocrystals by crystal field tuning

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiaofeng; Hu, Shigang [School of Information and Electrical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Tan, Congbing [Department of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201 (China); Liu, Yunxin, E-mail: lyunxin@163.com [Department of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201 (China)

    2015-04-15

    Graphical abstract: Crystal field tuning is a powerful approach for simultaneously enhancing the optical and magnetic properties of lanthanide-doped NaGdF{sub 4} bi-functional nanocrystals. - Abstract: Here, we show the simultaneous enhancement of fluorescent and paramagnetic properties in bifunctional NaGdF{sub 4}:Yb{sup 3+}/Er{sup 3+} nanocrystals by crystal field tuning. The energy level splitting calculation indicates, that lanthanide ionic pairs La{sup 3+}/Lu{sup 3+} introduced into the NaGdF{sub 4} host can modify the crystal field around emitters (e.g., Er{sup 3+} and Tm{sup 3+}) and sensitizers (e.g., Yb{sup 3+}) that result in the broadening of crystal field splitting of energy levels and the abundant multi-site distribution of upconversion luminescence. The optimization of the paramagnetic properties in NaGdF{sub 4} doped with emitters and sensitizers is ascribed to the lowering of anti-ferromagnetic coupling.

  17. Extreme Rainfall In A City

    Science.gov (United States)

    Nkemdirim, Lawrence

    Cities contain many structures and activities that are vulnerable to severe weather. Heavy precipitation cause floods which can damage structures, compromise transportation and water supply systems, and slow down economic and social activities. Rain induced flood patterns in cities must be well understood to enable effective placement of flood control and other regulatory measures. The planning goal is not to eliminate all floods but to reduce their frequency and resulting damage. Possible approaches to such planning include probability based extreme event analysis. Precipitation is normally the most variable hydrologic element over a given area. This variability results from the distribution of clouds and in cloud processes in the atmosphere, the storm path, and the distribution of topographical features on the ground along path. Some studies suggest that point rainfall patterns are also affected by urban industrial effects hence some agreement that cities are wetter than the country surrounding them. However, there are still questions regarding the intra- urban distribution of precipitation. The sealed surfaces, urban structures, and the urban heat anomaly increase convection in cities which may enhance the generation of clouds. Increased dust and gaseous aerosols loads are effective condensation and sublimation nuclei which may also enhance the generation of precipitation. Based on these associations, the greatest amount of convection type rainfall should occur at city center. A study of summer rainfall in Calgary showed that frequencies of trace amounts of rainfall and events under 0.2mm are highest downtown than elsewhere. For amounts greater than than 0.2 mm, downtown sites were not favored. The most compelling evidence for urban-industrial precipitation enhancement came from the Metromex project around St. Loius, Missouri where maximum increases of between 5 to 30 per cent in summer rainfall downwind of the city was linked to urbanization and

  18. Protein Adaptations in Archaeal Extremophiles

    Directory of Open Access Journals (Sweden)

    Christopher J. Reed

    2013-01-01

    Full Text Available Extremophiles, especially those in Archaea, have a myriad of adaptations that keep their cellular proteins stable and active under the extreme conditions in which they live. Rather than having one basic set of adaptations that works for all environments, Archaea have evolved separate protein features that are customized for each environment. We categorized the Archaea into three general groups to describe what is known about their protein adaptations: thermophilic, psychrophilic, and halophilic. Thermophilic proteins tend to have a prominent hydrophobic core and increased electrostatic interactions to maintain activity at high temperatures. Psychrophilic proteins have a reduced hydrophobic core and a less charged protein surface to maintain flexibility and activity under cold temperatures. Halophilic proteins are characterized by increased negative surface charge due to increased acidic amino acid content and peptide insertions, which compensates for the extreme ionic conditions. While acidophiles, alkaliphiles, and piezophiles are their own class of Archaea, their protein adaptations toward pH and pressure are less discernible. By understanding the protein adaptations used by archaeal extremophiles, we hope to be able to engineer and utilize proteins for industrial, environmental, and biotechnological applications where function in extreme conditions is required for activity.

  19. One-pot facile electrospinning construct of flexible Janus nanofibers with tunable and enhanced magnetism–photoluminescence bifunctionality

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liyan [Jilin Jianzhu University, Key Laboratory of Building Energy-Saving Technology Engineering, College of Materials Science and Engineering (China); Dong, Xiangting, E-mail: dongxiangting888@163.com [Changchun University of Science and Technology, Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province (China); Gai, Guangqing, E-mail: gaigq@163.com; Zhao, Li [Jilin Jianzhu University, Key Laboratory of Building Energy-Saving Technology Engineering, College of Materials Science and Engineering (China); Xu, Shuzhi [Jilin Business and Technology College, School of Biotechnology Engineering (China); Xiao, Xinfu [Jilin Jianzhu University, Key Laboratory of Building Energy-Saving Technology Engineering, College of Materials Science and Engineering (China)

    2015-02-15

    A novel nanostructure of flexible Janus nanofibers with tunable and enhanced magnetism–photoluminescence difunctionality has been successfully fabricated by one-pot electrospinning using specially designed parallel spinneret. Europium complex Eu(BA){sub 3}phen (BA = benzoic acid, phen = 1,10-phenanthroline), terbium complex Tb(BA){sub 3}phen, and Fe{sub 3}O{sub 4} nanoparticles (NPs) were, respectively, incorporated into polyvinyl pyrrolidone (PVP) and electrospun into Janus nanofibers. The morphology, structure, and property of the Janus nanofibers were investigated in detail by scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, fluorescence spectroscopy, and vibrating sample magnetometry. The average diameter of the Janus nanofibers is about ca. 300 nm. Every Janus nanofiber is composed of one nanofiber with different performances on two sides, one side is composed of Fe{sub 3}O{sub 4} NPs and PVP, and the other side consists of [Eu(BA){sub 3}phen + Tb(BA){sub 3}phen] and PVP. This novel nanostructures can effectively isolate Eu(BA){sub 3}phen and Tb(BA){sub 3}phen from Fe{sub 3}O{sub 4} NPs so that the exciting light and emitting light in the [Eu(BA){sub 3}phen + Tb(BA){sub 3}phen]/PVP domain will almost not be affected by Fe{sub 3}O{sub 4} NPs. The Janus nanofibers possess higher fluorescent intensity owing to their special nanostructure compared with non-Janus composite nanofiber with the same compositions. Moreover, the Janus nanofibers have multicolored and color-tunable photoluminescence, the emitting color could be tuned in a wide color range of red–yellow–green by adjusting the molar ratio of Eu(BA){sub 3}phen to Tb(BA){sub 3}phen under the excitation of 274-nm single-wavelength ultraviolet light, and the magnetism also could be tuned by changing the amounts of Fe{sub 3}O{sub 4} NPs. The new type Janus nanofibers with tunable and enhanced magnetism–photoluminescence bifunctionality have

  20. In vivo evaluation of a radiogallium-labeled bifunctional radiopharmaceutical, Ga-DOTA-MN2, for hypoxic tumor imaging

    International Nuclear Information System (INIS)

    On the basis of the findings obtained by X-ray crystallography of gadolinium-diethylenetriamine pentaacetic acid (Ga-DOTA) chelates and the drug design concept of bifunctional radiopharmaceuticals, we previously designed and synthesized a radiogallium-labeled DOTA chelate containing two metronidazole moieties, 67Ga-DOTA-MN2, for hypoxic tumor imaging. As expected, 67Ga-DOTA-MN2 exhibited high in vivo stability, although two carboxyl groups in the DOTA skeleton were conjugated with metronidazole moieties. In this study, we evaluated 67/68Ga-DOTA-MN2 as a nuclear imaging agent for hypoxic tumors. 67Ga-labeling of DOTA-MN2 with 67GaCl3 was achieved with high radiochemical yield (>85%) by 1-min of microwave irradiation (50 W). The pharmacokinetics of 67Ga-DOTA-MN2 were examined in mammary carcinoma (FM3A) tumor-bearing mice, and compared with those of 67Ga-DOTA-MN1 containing one metronidazole unit and '67Ga-DOTA. Upon administration, 67Ga-DOTA-MN2 exhibited higher accumulation in the implanted tumors than '67Ga-DOTA. Tumor-to-blood ratios of 67Ga-DOTA-MN2 were about two-fold higher than those of 67Ga-DOTA-MN1. Autoradiographic analysis showed the heterogeneous localization of '67Ga-DOTA-MN2 in the tumors, which corresponds to hypoxic regions suggested by well-established hypoxia marker drug, pimonidazole. Furthermore, in positron emission tomography (PET) study, the tumors of mice administered '68Ga-labeled DOTA-MN2 were clearly imaged by small-animal PET at 1 h after administration. This study demonstrates the potential usefulness of 67/68Ga-DOTA-MN2 as a nuclear imaging agent for hypoxic tumors and suggests that two functional moieties, such as metronidazole, can be conjugated to radiogallium-DOTA chelate without reducing the complex stability. The present findings provide useful information about the chemical design of radiogallium-labeled radiopharmaceuticals for PET and single photon emission computed tomography (SPECT) studies. (author)

  1. A nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistance genes in Enterococcus species

    Directory of Open Access Journals (Sweden)

    Ravichandran Manickam

    2007-12-01

    Full Text Available Abstract Background Enterococci have emerged as a significant cause of nosocomial infections in many parts of the world over the last decade. The most common enterococci strains present in clinical isolates are E. faecalis and E. faecium which have acquired resistant to either gentamicin or vancomycin. The conventional culture test takes 2–5 days to yield complete information of the organism and its antibiotic sensitivity pattern. Hence our present study was focused on developing a nanoplex PCR assay for the rapid detection of vancomycin and bifunctional aminoglycoside resistant enterococci (V-BiA-RE. This assay simultaneously detects 8 genes namely 16S rRNA of Enterococcus genus, ddl of E. faecalis and E. faecium, aacA-aphD that encodes high level gentamicin resistance (HLGR, multilevel vancomycin resistant genotypes such as vanA, vanB, vanC and vanD and one internal control gene. Results Unique and specific primer pairs were designed to amplify the 8 genes. The specificity of the primers was confirmed by DNA sequencing of the nanoplex PCR products and BLAST analysis. The sensitivity and specificity of V-BiA-RE nanoplex PCR assay was evaluated against the conventional culture method. The analytical sensitivity of the assay was found to be 1 ng at the DNA level while the analytical specificity was evaluated with 43 reference enterococci and non-enterococcal strains and was found to be 100%. The diagnostic accuracy was determined using 159 clinical specimens, which showed that 97% of the clinical isolates belonged to E. faecalis, of which 26% showed the HLGR genotype, but none were vancomycin resistant. The presence of an internal control in the V-BiA-RE nanoplex PCR assay helped us to rule out false negative cases. Conclusion The nanoplex PCR assay is robust and can give results within 4 hours about the 8 genes that are essential for the identification of the most common Enterococcus spp. and their antibiotic sensitivity pattern. The PCR assay

  2. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Final technical progress report, September 12, 1991--December 11, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Klier, K.; Herman, R.G.; Deemer, M.; Richards-Babb, M.; Carr, T.

    1995-07-01

    The objective of this research was to investigate sulfur-resistant catalysts for the conversion of synthesis gas having H{sub 2}/CO {le} 1 into C{sub 1}--C{sub 4} alcohols, especially ethanol, by a highly selective and efficient pathway, while also promoting the water gas shift reaction (WGSR). The catalysts chosen are bifunctional, base-hydrogenation, sulfur-tolerant transition metal sulfides with heavy alkali, e.g. Cs{sup +}, promoter dispersed on their surfaces. The modes of activation of H{sub 2} and CO on MoS{sub 2} and alkali-doped MoS{sub 2} were considered, and computational analyses of the thermodynamic stability of transition metal sulfides and of the electronic structure of these sulfide catalysts were carried out. In the preparation of the cesium-promoted MoS{sub 2} catalysts, a variety of preparation methods using CsOOCH were examined. In all cases, doping with CsOOCH led to a lost of surface area. The undoped molybdenum disulfide catalyst only produced hydrocarbons. Cs-doped MoS{sub 2} catalysts all produced linear alcohols, along with smaller amounts of hydrocarbons. With a 20 wt% CsOOCH/MoS{sub 2} catalyst, temperature, pressure, and flow rate dependences of the synthesis reactions were investigated in the presence and absence of H{sub 2}S in the H{sub 2}/CO = 1/1 synthesis gas during short term testing experiments. It was shown that with a carefully prepared 10 wt% CsOOCH/MoS{sub 2} catalyst, reproducible and high alcohol synthesis activity could be obtained. For example, at 295 C with H{sub 2}/CO = 1 synthesis gas at 8.3 MPa and with GHSV = 7,760 l/kg cat/hr, the total alcohol space time yield was ca 300 g/kg cat/hr (accompanied with a hydrocarbon space time yield of ca 60 g/kg cat/hr). Over a testing period of ca 130 hr, no net deactivation of the catalyst was observed. 90 refs., 82 figs., 14 tabs.

  3. Remembrance of ecohydrologic extremes past

    Science.gov (United States)

    Band, L. E.; Hwang, T.

    2013-12-01

    Ecohydrological systems operate at time scales that span several orders of magnitude. Significant processes and feedbacks range from subdaily physiologic response to meteorological drivers, to soil forming and geomorphic processes ranging up through 10^3-10^4 years. While much attention in ecohydrology has focused on ecosystem optimization paradigms, these systems can show significant transience in structure and function, with apparent memory of hydroclimate extremes and regime shifts. While optimization feedbacks can be reconciled with system transience, a better understanding of the time scales and mechanisms of adjustment to increased hydroclimate variability and to specific events is required to understand and predict dynamics and vulnerability of ecosystems. Under certain circumstances of slowly varying hydroclimate, we hypothesize that ecosystems can remain adjusted to changing climate regimes, without displaying apparent system memory. Alternatively, rapid changes in hydroclimate and increased hydroclimate variability, amplified with well expressed non-linearity in the processes controlling feedbacks between water, carbon and nutrients, can move ecosystems far from adjusted states. The Coweeta Hydrological Laboratory is typical of humid, broadleaf forests in eastern North America, with a range of forest biomes from northern hardwoods at higher elevations, to oak-pine assemblages at lower elevations. The site provides almost 80 years of rainfall-runoff records for a set of watersheds under different management, along with multi-decadal forest plot structural information, soil moisture conditions and stream chemistry. An initial period of multi-decadal cooling, was followed by three decades of warming and increased hydroclimate variability. While mean temperature has risen over this time period, precipitation shows no long term trends in the mean, but has had a significant rise in variability with repeated extreme drought and wet periods. Over this latter

  4. Polyimide Resins Resist Extreme Temperatures

    Science.gov (United States)

    2009-01-01

    Spacecraft and aerospace engines share a common threat: high temperature. The temperatures experienced during atmospheric reentry can reach over 2,000 F, and the temperatures in rocket engines can reach well over 5,000 F. To combat the high temperatures in aerospace applications, Dr. Ruth Pater of Langley Research Center developed RP-46, a polyimide resin capable of withstanding the most brutal temperatures. The composite material can push the service temperature to the limits of organic materials. Designed as an environmentally friendly alternative to other high-temperature resins, the RP-46 polyimide resin system was awarded a 1992 "R&D 100" award, named a "2001 NASA Technology of the Year," and later, due to its success as a spinoff technology, "2004 NASA Commercial Invention of the Year." The technology s commercial success also led to its winning the Langley s "Paul F. Holloway Technology Transfer Award" as well as "Richard T. Whitcom Aerospace Technology Transfer Award" both for 2004. RP-46 is relatively inexpensive and it can be readily processed for use as an adhesive, composite, resin molding, coating, foam, or film. Its composite materials can be used in temperatures ranging from minus 150 F to 2,300 F. No other organic materials are known to be capable of such wide range and extreme high-temperature applications. In addition to answering the call for environmentally conscious high-temperature materials, RP-46 provides a slew of additional advantages: It is extremely lightweight (less than half the weight of aluminum), chemical and moisture resistant, strong, and flexible. Pater also developed a similar technology, RP-50, using many of the same methods she used with RP-46, and very similar in composition to RP-46 in terms of its thermal capacity and chemical construction, but it has different applications, as this material is a coating as opposed to a buildable composite. A NASA license for use of this material outside of the Space Agency as well as

  5. Extreme Mechanics of Growing Matter

    Science.gov (United States)

    Kuhl, Ellen

    2013-03-01

    Growth is a distinguishing feature of all living things. Unlike standard materials, living matter can autonomously respond to alterations in its environment. As a result of a continuous ultrastructural turnover and renewal of cells and extracellular matrix, living matter can undergo extreme changes in composition, size, and shape within the order of months, weeks, or days. While hard matter typically adapts by increasing its density to grow strong, soft matter adapts by increasing its volume to grow large. Here we provide a state-of-the-art review of growing matter, and compare existing mathematical models for growth and remodeling of living systems. Applications are plentiful ranging from plant growth to tumor growth, from asthma in the lungs to restenosis in the vasculature, from plastic to reconstructive surgery, and from skeletal muscle adaptation to heart failure. Using these examples, we discuss current challenges and potential future directions. We hope to initiate critical discussions around the biophysical modeling of growing matter as a powerful tool to better understand biological systems in health and disease. This research has been supported by the NSF CAREER award CMMI 0952021.

  6. The Extreme Case of Magnetars

    Science.gov (United States)

    Kouveliotou, Chryssa

    2011-01-01

    Magnetars are magnetically powered rotating neutron stars with extreme magnetic fields (over 10(exp 14) Gauss). They were discovered in the X- and gamma-rays where they predominantly emit their radiation. Very few sources (roughly 18) have been found since their discovery in 1987. NASA's Fermi Gamma-ray Space Telescope was launched June 11, 2009; since then the Fermi Gamma-ray Burst Monitor (GBM) recorded emission from four magnetar sources. Two of these were brand new sources, SGR J0501+4516, discovered with Swift and extensively monitored with Swift and GBM, SGR J0418+5729, discovered with GBM and the Interplanetary Network (IPN). A third was SGR J1550-5418, a source originally classified as an Anomalous X-ray Pulsar (AXP 1E1547.0-5408), but exhibiting a very prolific outburst with over 400 events recorded in January 2009. In my talk I will give a short history of magnetars and describe how this, once relatively esoteric field, has emerged as a link between several astrophysical areas including Gamma-Ray Bursts. Finally, I will describe the exciting new results of Fermi in this field and the current status of our knowledge of the magnetar population properties and magnetic fields.

  7. An extremely primitive halo star

    CERN Document Server

    Caffau, E; François, P; Sbordone, L; Monaco, L; Spite, M; Spite, F; Ludwig, H -G; Cayrel, R; Zaggia, S; Hammer, F; Randich, S; Molaro, P; Hill, V; 10.1038/nature10377

    2012-01-01

    The early Universe had a chemical composition consisting of hydrogen, helium and traces of lithium1, almost all other elements were created in stars and supernovae. The mass fraction, Z, of elements more massive than helium, is called "metallicity". A number of very metal poor stars have been found some of which, while having a low iron abundance, are rich in carbon, nitrogen and oxygen. For theoretical reasons and because of an observed absence of stars with metallicities lower than Z=1.5E-5, it has been suggested that low mass stars (M<0.8M\\odot, the ones that survive to the present day) cannot form until the interstellar medium has been enriched above a critical value, estimated to lie in the range 1.5E-8\\leqZ\\leq1.5E-6, although competing theories claiming the contrary do exist. Here we report the chemical composition of a star with a very low Z\\leq6.9E-7 (4.5E-5 of that of the Sun) and a chemical pattern typical of classical extremely metal poor stars, meaning without the enrichment of carbon, nitroge...

  8. Driving Extreme Efficiency to Market

    Science.gov (United States)

    Garbesi, Karina

    2014-03-01

    The rapid development of extremely energy efficient appliances and equipment is essential to curtail catastrophic climate disruption. This will require the on-going development of products that apply all best-practices and that take advantage of the synergies of hybridization and building integration. Beyond that, it requires the development of new disruptive technologies and concepts. To facilitate these goals, in 2011 the Lawrence Berkeley National Laboratory and the U.S. Department of Energy launched the Max Tech and Beyond Design Competition for Ultra-Low-Energy-Use Appliances and Equipment. Now in its third year, the competition supports faculty-lead student design teams at U.S. universities to develop and test new technology prototypes. This talk describes what the competition and the Max Tech Program are doing to drive such rapid technology progress and to facilitate the entry to the market of successful Max Tech prototypes. The talk also initiates a discussion of physicists' unique role in driving that technology progress faster and farther. Emerging Technologies, Building Technologies Office, U.S. Department of Energy.

  9. Products in Conditional Extreme Value Model

    CERN Document Server

    Hazra, Rajat Subhra

    2011-01-01

    The classical multivariate extreme value theory tries to capture the extremal dependence between the components under a multivariate domain of attraction condition and it requires each of the components to be in the domain of attraction of a univariate extreme value distribution as well. The multivariate extreme value (MEV) model has a rich theory but has some limitations as it fails to capture the dependence structure in presence of asymptotic independence. A different approach to MEV was given by Heffernan and Tawn (2004), where they examined MEV distributions by conditioning on one of the components to be extreme. Here we assume one of the components to be in Frech\\'et or Weibull domain of attraction and study the behavior of the product of the components under this conditional extreme value model.

  10. Extreme Learning Machine for land cover classification

    OpenAIRE

    Pal, Mahesh

    2008-01-01

    This paper explores the potential of extreme learning machine based supervised classification algorithm for land cover classification. In comparison to a backpropagation neural network, which requires setting of several user-defined parameters and may produce local minima, extreme learning machine require setting of one parameter and produce a unique solution. ETM+ multispectral data set (England) was used to judge the suitability of extreme learning machine for remote sensing classifications...

  11. Extreme Value Theory for Finance: A Survey

    OpenAIRE

    Rocco, Marco

    2010-01-01

    Extreme value theory is concerned with the study of the asymptotical distribution of extreme events, that is to say events which are rare in frequency and huge with respect to the majority of observations. Statistical methods derived from this theory have been increasingly employed in finance, especially in the context of risk measurement. The aim of the present study is twofold. The first part delivers a critical review of the theoretical underpinnings of extreme value theory. The second par...

  12. Directional Multivariate Extremes in Environmental Phenomena

    OpenAIRE

    Torres, Raúl; De Michele, Carlo; Laniado, Henry; Lillo, Rosa E.

    2016-01-01

    Several environmental phenomena can be described by different correlated variables that must be considered jointly in order to be more representative of the nature of these phenomena. For such events, identification of extremes is inappropriate if it is based on marginal analysis. Extremes have usually been linked to the notion of quantile, which is an important tool to analyze risk in the univariate setting. We propose to identify multivariate extremes and analyze environmental phenomena in ...

  13. Extreme events: dynamics, statistics and prediction

    OpenAIRE

    M. Ghil; Yiou, P.; S. Hallegatte; B. D. Malamud; Naveau, P.; A. Soloviev; Friederichs, P.; Keilis-Borok, V.; Kondrashov, D.; V. Kossobokov; Mestre, O.; Nicolis, C.; Rust, H. W.; P. Shebalin; Vrac, M.

    2011-01-01

    We review work on extreme events, their causes and consequences, by a group of European and American researchers involved in a three-year project on these topics. The review covers theoretical aspects of time series analysis and of extreme value theory, as well as of the deterministic modeling of extreme events, via continuous and discrete dynamic models. The applications include climatic, seismic and socio-economic events, along with their prediction.

    Two important resul...

  14. Extreme weather events and infectious disease outbreaks

    OpenAIRE

    Anthony J McMichael

    2015-01-01

    Human-driven climatic changes will fundamentally influence patterns of human health, including infectious disease clusters and epidemics following extreme weather events. Extreme weather events are projected to increase further with the advance of human-driven climate change. Both recent and historical experiences indicate that infectious disease outbreaks very often follow extreme weather events, as microbes, vectors and reservoir animal hosts exploit the disrupted social and environmental c...

  15. Extreme wind turbine response during operation

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, S.R.K.

    2007-01-01

    Estimation of extreme response values is very important for structural design of wind turbines. Due to the influence of control system and nonlinear structural behavior the extreme response is usually assessed based on simulation of turbulence time series. In this paper the problem of statistical...... load extrapolation is considered using techniques from structural reliability theory. Different simulation techniques to estimate extreme response characteristics are described and compared, including crude Monte Carlo simulation, Importance Sampling, and splitting methods such as the Russian Roulette...

  16. Extreme Metal Music and Anger Processing

    OpenAIRE

    Genevieve Anita Dingle

    2015-01-01

    The claim that listening to extreme music causes anger and expressions of anger such as aggression and delinquency has yet to be substantiated using controlled experimental methods. In this study, 39 extreme music listeners aged 18 to 34 years were subjected to an anger induction, followed by random assignment to 10 minutes of listening to extreme music from their own playlist, or 10 minutes of silence (control). Measures of emotion included heart rate and subjective ratings on the Positive a...

  17. Protein Adaptations in Archaeal Extremophiles

    OpenAIRE

    Reed, Christopher J; Hunter Lewis; Eric Trejo; Vern Winston; Caryn Evilia

    2013-01-01

    Extremophiles, especially those in Archaea, have a myriad of adaptations that keep their cellular proteins stable and active under the extreme conditions in which they live. Rather than having one basic set of adaptations that works for all environments, Archaea have evolved separate protein features that are customized for each environment. We categorized the Archaea into three general groups to describe what is known about their protein adaptations: thermophilic, psychrophilic, and halophil...

  18. Understanding Protein Non-Folding

    OpenAIRE

    Vladimir N. Uversky; Dunker, A Keith

    2010-01-01

    This review describes the family of intrinsically disordered proteins, members of which fail to form rigid 3-D structures under physiological conditions, either along their entire lengths or only in localized regions. Instead, these intriguing proteins/regions exist as dynamic ensembles within which atom positions and backbone Ramachandran angles exhibit extreme temporal fluctuations without specific equilibrium values. Many of these intrinsically disordered proteins are known to carry out im...

  19. Hydrodesulfurization on Transition Metal Catalysts: Elementary Steps of C-S Bond Activation and Consequences of Bifunctional Synergies

    Science.gov (United States)

    Yik, Edwin Shyn-Lo

    surfaces. Our interpretations place HDS in a specific class of more general C-X hydrogenolysis reactions, including hydrodeoxygenation (HDO) that has gained popular appeal in recent biomass conversion processes. These hydrodearomatization routes, hydrogenolysis and hydrogenation, act as probes for studying hydrogen spillover, a frequently observed phenomenon in bifunctional systems. Indeed, we observe enhancements solely in the rates of thiophene hydrogenation when monofunctional catalysts, which generate equilibrated concentrations of surface H-species, are mixed with materials (e.g. Al 2O3) that cannot dissociate H2. Conventional mechanisms that suggest gas phase or surface diffusion of atomic H-species (or H +-e- pairs) are implausible across distances along insulating surfaces (i.e. SiO2, Al2O3). We propose, with kinetic-transport models that are consistent with all observed behaviors, that mobility of active H-species occurs through gas phase diffusion of thiophene-derived molecular H-carriers, whose formation rate on HDS sites can control maximum spillover enhancements. This synergy is disrupted when the ability of thiophene to form these H-carriers is suppressed, leading to an absence of spillover-mediated rates and further challenging any diffusive roles of atomic H-species. Such implications help guide optimal designs of bifunctional cascades to permit the uninhibited access and egress of larger molecules within both catalytic functions. (Abstract shortened by UMI.).

  20. Extreme Events in Nature and Society

    CERN Document Server

    Albeverio, Sergio; Kantz, Holger

    2006-01-01

    Significant, and usually unwelcome, surprises, such as floods, financial crisis, epileptic seizures, or material rupture, are the topics of Extreme Events in Nature and Society. The book, authored by foremost experts in these fields, reveals unifying and distinguishing features of extreme events, including problems of understanding and modelling their origin, spatial and temporal extension, and potential impact. The chapters converge towards the difficult problem of anticipation: forecasting the event and proposing measures to moderate or prevent it. Extreme Events in Nature and Society will interest not only specialists, but also the general reader eager to learn how the multifaceted field of extreme events can be viewed as a coherent whole.