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Sample records for bound carbohydrate complexes

  1. Complex bounds for multimodal maps: bounded combinatorics

    OpenAIRE

    Smania, Daniel

    2000-01-01

    We proved the so called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus. The complex bounds is the first step to extend the renormalization theory of unimodal maps to multimodal maps.

  2. Space-bounded communication complexity

    DEFF Research Database (Denmark)

    Brody, Joshua Eric; Chen, Shiteng; Papakonstantinou, Periklis A.;

    2013-01-01

    In the past thirty years, Communication Complexity has emerged as a foundational tool to proving lower bounds in many areas of computer science. Its power comes from its generality, but this generality comes at a price---no superlinear communication lower bound is possible, since a player may...... communicate his entire input. However, what if the players are limited in their ability to recall parts of their interaction? We introduce memory models for 2-party communication complexity. Our general model is as follows: two computationally unrestricted players, Alice and Bob, each have s(n) bits of memory...

  3. Molecular simulations of carbohydrate-protein complexes

    OpenAIRE

    Eid, Sameh Mansour Abbas

    2013-01-01

    I. Generation and validation of a free-energy model for carbohydrate binding. Carbohy-drates play a key role in a variety of physiological and pathological processes and, hence, represent a rich source for the development of novel therapeutic agents. Being able to predict binding mode and binding affinity is an essential, yet lacking, aspect of the stru-cture-based design of carbohydrate-based ligands. To this end, we assembled a diverse data set of 316 carbohydrate–protein crystal structu...

  4. Food-derived carbohydrates--structural complexity and functional diversity.

    Science.gov (United States)

    Tharanathan, Rudrapatnam N

    2002-01-01

    Carbohydrates are biomolecules abundantly available in nature. They are found in bewildering types ranging from simple sugars through oligo- and polysaccharides to glycoconjugates and saccharide complexes, each exhibiting characteristic bio-physiological and/or nutritional functions both in in vivo and in vitro systems. For example, their presence or inclusion in food dictates the texture (body) and gives desirable customer appeal (satisfaction), or their inclusion in the diet offers beneficial effects of great therapeutic value. Thus, carbohydrates are integrally involved in a multitude of biological functions such as regulation of the immune system, cellular signaling (communication), cell malignancy, antiinfection responses, host-pathogen interactions, etc. If starch is considered the major energy storage carbohydrate, the gums/mucilages and other non-starch carbohydrates are of structural significance. The most investigated properties of starch are its gelatinization and melting behavior, especially during food processing. This has led to the development of the food polymer science approach, which has enabled a new interpretive and experimental frame work for the study of the plasticizing influence of simple molecules such as water, sugars, etc. on food systems that are kinetically constrained. Starch, although considered fully digestible, has been challenged, and starch is found to be partly indigestible in the GI tract of humans. This fraction of starch-resisting digestion in vivo is known as resistant starch (RS). The latter, due to its excellent fermentative capacity in the gut, especially yielding butyric acid is considered a new tool for the creation of fiber-rich foods, which are of nutraceutical importance. By a careful control of the processing conditions the content of RS, a man-made fiber, can be increased to as high as 30%. Arabinoxylans are the major endospermic cell wall polysaccharides of cereals. In wheat they are found complexed with ferulic

  5. Carbohydrates

    Science.gov (United States)

    ... girls Eating healthy at restaurants Special food issues Vegetarian eating Eating for strong bones Quiz: Food Facts Links to more information girlshealth glossary girlshealth.gov home http://www.girlshealth.gov/ Home Nutrition Nutrition basics Carbohydrates Carbohydrates Carbohydrates (say: kar-boh- ...

  6. Comparative analysis of carbohydrate active enzymes in Clostridium termitidis CT1112 reveals complex carbohydrate degradation ability.

    Directory of Open Access Journals (Sweden)

    Riffat I Munir

    Full Text Available Clostridium termitidis strain CT1112 is an anaerobic, gram positive, mesophilic, cellulolytic bacillus isolated from the gut of the wood-feeding termite, Nasutitermes lujae. It produces biofuels such as hydrogen and ethanol from cellulose, cellobiose, xylan, xylose, glucose, and other sugars, and therefore could be used for biofuel production from biomass through consolidated bioprocessing. The first step in the production of biofuel from biomass by microorganisms is the hydrolysis of complex carbohydrates present in biomass. This is achieved through the presence of a repertoire of secreted or complexed carbohydrate active enzymes (CAZymes, sometimes organized in an extracellular organelle called cellulosome. To assess the ability and understand the mechanism of polysaccharide hydrolysis in C. termitidis, the recently sequenced strain CT1112 of C. termitidis was analyzed for both CAZymes and cellulosomal components, and compared to other cellulolytic bacteria. A total of 355 CAZyme sequences were identified in C. termitidis, significantly higher than other Clostridial species. Of these, high numbers of glycoside hydrolases (199 and carbohydrate binding modules (95 were identified. The presence of a variety of CAZymes involved with polysaccharide utilization/degradation ability suggests hydrolysis potential for a wide range of polysaccharides. In addition, dockerin-bearing enzymes, cohesion domains and a cellulosomal gene cluster were identified, indicating the presence of potential cellulosome assembly.

  7. Carbohydrates

    Science.gov (United States)

    Abumrad NA, Nassi F, Marcus A. Digestion and absorption of dietary fat, carbohydrate, and protein. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 10th ed. ...

  8. Carbohydrate Content in the GDM Diet: Two Views: View 1: Nutrition Therapy in Gestational Diabetes: The Case for Complex Carbohydrates.

    Science.gov (United States)

    Hernandez, Teri L

    2016-05-01

    IN BRIEF Restriction of dietary carbohydrate has been the cornerstone for treatment of gestational diabetes mellitus (GDM). However, there is evidence that a balanced liberalization of complex carbohydrate as part of an overall eating plan in GDM meets treatment goals and may mitigate maternal adipose tissue insulin resistance, both of which may promote optimal metabolic outcomes for mother and offspring. PMID:27182176

  9. Carbohydrates

    Science.gov (United States)

    ... is fine because they contain important vitamins and minerals. But your body rapidly digests the starch in white potatoes. This can raise your blood glucose level. Healthy carbohydrates include: Natural sugars in fruits, vegetables, milk, and milk products Dietary fiber Starches in whole- ...

  10. Modeling of Carbohydrate Binding Modules Complexed to Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Nimlos, M. R.; Beckham, G. T.; Bu, L.; Himmel, M. E.; Crowley, M. F.; Bomble, Y. J.

    2012-01-01

    Modeling results are presented for the interaction of two carbohydrate binding modules (CBMs) with cellulose. The family 1 CBM from Trichoderma reesei's Cel7A cellulase was modeled using molecular dynamics to confirm that this protein selectively binds to the hydrophobic (100) surface of cellulose fibrils and to determine the energetics and mechanisms for locating this surface. Modeling was also conducted of binding of the family 4 CBM from the CbhA complex from Clostridium thermocellum. There is a cleft in this protein, which may accommodate a cellulose chain that is detached from crystalline cellulose. This possibility is explored using molecular dynamics.

  11. Lower Complexity Bounds for Lifted Inference

    CERN Document Server

    Jaeger, Manfred

    2012-01-01

    One of the big challenges in the development of probabilistic relational (or probabilistic logical) modeling and learning frameworks is the design of inference techniques that operate on the level of the abstract model representation language, rather than on the level of ground, propositional instances of the model. Numerous approaches for such "lifted inference" techniques have been proposed. While it has been demonstrated that these techniques will lead to significantly more efficient inference on some specific models, there are only very recent and still quite restricted results that show the feasibility of lifted inference on certain syntactically defined classes of models. Lower complexity bounds that imply some limitations for the feasibility of lifted inference on more expressive model classes were established early on in (Jaeger 2000). However, it is not immediate that these results also apply to the type of modeling languages that currently receive the most attention, i.e., weighted, quantifier-free ...

  12. Complex carbohydrate utilization by the healthy human microbiome.

    Directory of Open Access Journals (Sweden)

    Brandi L Cantarel

    Full Text Available The various ecological habitats in the human body provide microbes a wide array of nutrient sources and survival challenges. Advances in technology such as DNA sequencing have allowed a deeper perspective into the molecular function of the human microbiota than has been achievable in the past. Here we aimed to examine the enzymes that cleave complex carbohydrates (CAZymes in the human microbiome in order to determine (i whether the CAZyme profiles of bacterial genomes are more similar within body sites or bacterial families and (ii the sugar degradation and utilization capabilities of microbial communities inhabiting various human habitats. Upon examination of 493 bacterial references genomes from 12 human habitats, we found that sugar degradation capabilities of taxa are more similar to others in the same bacterial family than to those inhabiting the same habitat. Yet, the analysis of 520 metagenomic samples from five major body sites show that even when the community composition varies the CAZyme profiles are very similar within a body site, suggesting that the observed functional profile and microbial habitation have adapted to the local carbohydrate composition. When broad sugar utilization was compared within the five major body sites, the gastrointestinal track contained the highest potential for total sugar degradation, while dextran and peptidoglycan degradation were highest in oral and vaginal sites respectively. Our analysis suggests that the carbohydrate composition of each body site has a profound influence and probably constitutes one of the major driving forces that shapes the community composition and therefore the CAZyme profile of the local microbial communities, which in turn reflects the microbiome fitness to a body site.

  13. Bounds on Transient Instability for Complex Ecosystems

    Science.gov (United States)

    2016-01-01

    Stability is a desirable property of complex ecosystems. If a community of interacting species is at a stable equilibrium point then it is able to withstand small perturbations to component species’ abundances without suffering adverse effects. In ecology, the Jacobian matrix evaluated at an equilibrium point is known as the community matrix, which describes the population dynamics of interacting species. A system’s asymptotic short- and long-term behaviour can be determined from eigenvalues derived from the community matrix. Here we use results from the theory of pseudospectra to describe intermediate, transient dynamics. We first recover the established result that the transition from stable to unstable dynamics includes a region of ‘transient instability’, where the effect of a small perturbation to species’ abundances—to the population vector—is amplified before ultimately decaying. Then we show that the shift from stability to transient instability can be affected by uncertainty in, or small changes to, entries in the community matrix, and determine lower and upper bounds to the maximum amplitude of perturbations to the population vector. Of five different types of community matrix, we find that amplification is least severe when predator-prey interactions dominate. This analysis is relevant to other systems whose dynamics can be expressed in terms of the Jacobian matrix. PMID:27327511

  14. Bounds on Transient Instability for Complex Ecosystems.

    Directory of Open Access Journals (Sweden)

    Francesco Caravelli

    Full Text Available Stability is a desirable property of complex ecosystems. If a community of interacting species is at a stable equilibrium point then it is able to withstand small perturbations to component species' abundances without suffering adverse effects. In ecology, the Jacobian matrix evaluated at an equilibrium point is known as the community matrix, which describes the population dynamics of interacting species. A system's asymptotic short- and long-term behaviour can be determined from eigenvalues derived from the community matrix. Here we use results from the theory of pseudospectra to describe intermediate, transient dynamics. We first recover the established result that the transition from stable to unstable dynamics includes a region of 'transient instability', where the effect of a small perturbation to species' abundances-to the population vector-is amplified before ultimately decaying. Then we show that the shift from stability to transient instability can be affected by uncertainty in, or small changes to, entries in the community matrix, and determine lower and upper bounds to the maximum amplitude of perturbations to the population vector. Of five different types of community matrix, we find that amplification is least severe when predator-prey interactions dominate. This analysis is relevant to other systems whose dynamics can be expressed in terms of the Jacobian matrix.

  15. Bounds on Transient Instability for Complex Ecosystems.

    Science.gov (United States)

    Caravelli, Francesco; Staniczenko, Phillip P A

    2016-01-01

    Stability is a desirable property of complex ecosystems. If a community of interacting species is at a stable equilibrium point then it is able to withstand small perturbations to component species' abundances without suffering adverse effects. In ecology, the Jacobian matrix evaluated at an equilibrium point is known as the community matrix, which describes the population dynamics of interacting species. A system's asymptotic short- and long-term behaviour can be determined from eigenvalues derived from the community matrix. Here we use results from the theory of pseudospectra to describe intermediate, transient dynamics. We first recover the established result that the transition from stable to unstable dynamics includes a region of 'transient instability', where the effect of a small perturbation to species' abundances-to the population vector-is amplified before ultimately decaying. Then we show that the shift from stability to transient instability can be affected by uncertainty in, or small changes to, entries in the community matrix, and determine lower and upper bounds to the maximum amplitude of perturbations to the population vector. Of five different types of community matrix, we find that amplification is least severe when predator-prey interactions dominate. This analysis is relevant to other systems whose dynamics can be expressed in terms of the Jacobian matrix. PMID:27327511

  16. Synthesis, characterization and cytotoxic activity of palladium (II) carbohydrate complexes

    Indian Academy of Sciences (India)

    S Bhavya Deepthi; Rajiv Trivedi; P Sujitha; C Ganesh Kumar; B Sridhar; Suresh K Bhargava

    2012-11-01

    Carbohydrate containing pyridyl triazole ligands, 5-deoxy-1,2--isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazole-1-yl)--D-xylofuranose (2a), 3--Benzyl-5-deoxy-1,2--isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)--D-xylofuranose (2b), methyl-5-deoxy-2,3--isopropylidene-5-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)--D-ribofuranoside, (2c) and 6-deoxy-1,2:3,4-di--isopropylidene-6-(4-(2-pyridyl)-1H-1,2,3-triazol-1-yl)--D-galactopyranose (2d) were prepared by the `click’ reaction of 2-ethynyl pyridine with the corresponding azides. The palladium complexes were synthesised by the reaction of pyridyl triazole ligands with [Pd(COD)Cl2] in dichloromethane. All the compounds were characterized by NMR, IR, mass and elemental analysis. Structural characterization of the ligand 2a was done by X-ray crystallography. The ligands and complexes were tested for their cytotoxic activity on different cell lines like A549 (human alveolar adenocarcinoma cells), Neuro2a (mouse neuroblastoma cells), HeLa (cervical carcinoma cancer cells), MDA-MB-231 (human breast adenocarcinoma cells) and MCF7 (human breast adenocarcinoma cells). The complexes showed considerable cytotoxicity while the ligands were non-toxic on the tested cell lines.

  17. The center for plant and microbial complex carbohydrates at the University of Georgia Complex Carbohydrate Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, P.; Darvill, A.

    1991-08-01

    Research from the Complex Carbohydrates Research Center at the University of Georgia is presented. Topics include: Structural determination of soybean isoflavones which specifically induce Bradyrhizobium japonicum nodD1 but not the nodYABCSUIJ operon; structural analysis of the lipopolysaccharides (LPSs) from symbiotic mutants of Bradyrhizobium japonicum; structural characterization of lipooligosaccharides from Bradyrhizobium japonicum that are required for the specific nodulation of soybean; structural characterization of the LPSs from R. Leguminosarum biovar phaseoli, the symbiont of bean; characterization of bacteroid-specific LPS epitopes in R. leguminosarum biovar viciae; analysis of the surface polysaccharides of Rhizobium meliloti mutants whose lipopolysaccharides and extracellular polysaccharides can have the same function in symbiosis; characterization of a polysaccharide produced by certain Bradyrhizobium japonicum strains within soybean nodules; structural analysis of a streptococcal adhesin polysaccharide receptor; conformational studies of xyloglucan, the role of the fucosylated side chain in surface-specific cellulose-xyloglucan interactions; the structure of an acylated glucosamine oligosaccharide signal molecule (nod factor) involved in the symbiosis of Rhizobium leguminosarum biovar viciae with its host Vicia sativa; investigating membrane responses induced by oligogalacturonides in cultured cells; the polygalacturonase inhibitor protein; characterization of the self-incompatability glycoproteins from Petunia hybrida; investigation of the cell wall polysaccharide structures of Arabidopsis thaliana; and the glucan inhibition of virus infection of tabacco.

  18. Complexity Considerations, cSAT Lower Bound

    CERN Document Server

    Hofman, Radoslaw

    2007-01-01

    This article discusses completeness of Boolean Algebra as First Order Theory in Goedel's meaning. If Theory is complete then any possible transformation is equivalent to some transformation using axioms, predicates etc. defined for this theory. If formula is to be proved (or disproved) then it has to be reduced to axioms. If every transformation is deducible then also optimal transformation is deducible. If every transformation is exponential then optimal one is too, what allows to define lower bound for discussed problem to be exponential (outside P). Then we show algorithm for NDTM solving the same problem in O(n^c) (so problem is in NP), what proves that P \

  19. A quadratically tight partition bound for classical communication complexity and query complexity

    OpenAIRE

    Jain, Rahul; Lee, Troy; Vishnoi, Nisheeth K.

    2014-01-01

    In this work we introduce, both for classical communication complexity and query complexity, a modification of the 'partition bound' introduced by Jain and Klauck [2010]. We call it the 'public-coin partition bound'. We show that (the logarithm to the base two of) its communication complexity and query complexity versions form, for all relations, a quadratically tight lower bound on the public-coin randomized communication complexity and randomized query complexity respectively.

  20. The pervasive reach of resource-bounded Kolmogorov complexity in computational complexity theory

    OpenAIRE

    Allender, E.; Koucký, M.; Ronneburger, D.; Roy, S.

    2011-01-01

    We continue an investigation into resource-bounded Kolmogorov complexity, which highlights the close connections between circuit complexity and Levin's time-bounded Kolmogorov complexity measure Kt (and other measures with a similar flavor), and also exploits derandomization techniques to provide new insights regarding Kolmogorov complexity. The Kolmogorov measures that have been introduced have many advantages over other approaches to defining resource-bounded Kolmogorov complexity. Here, we...

  1. CHANGES IN COMPLEX CARBOHYDRATE CONTENT AND STRUCTURE IN RAT LUNGS CAUSED BY PROLONGED OZONE INHALATION

    Science.gov (United States)

    EPA GRANT NUMBER: R828112C065IIITitle: Changes in Complex Carbohydrate Content and Structure in Rat Lungs Caused by Prolonged Ozone InhalationInvestigator: Bhandaru RadhakrishnamurthyInstitution: Tulane University of LouisianaEPA...

  2. Bounds on transient instability for complex ecosystems

    OpenAIRE

    Caravelli, Francesco; Staniczenko, Phillip P. A.

    2015-01-01

    Stability is a desirable property of complex ecosystems. If a community of interacting species is at a stable equilibrium point then it is able to withstand small perturbations to component species' abundances without suffering adverse effects. In ecology, the Jacobian matrix evaluated at an equilibrium point is known as the community matrix, which describes the population dynamics of interacting species. A system's asymptotic short- and long-term behaviour can be determined from eigenvalues ...

  3. COMPLEXITY OF LARGE TIME BEHAVIOUR OFEVOLUTION EQUATIONS WITH BOUNDED DATA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The authors study the asymptotic behaviour of solutions of the heat equation and a number of evolution equations using scaling techniques. It is proved that in the framework of bounded data stabilization need not occur and the general asymptotic behaviour is complex. This behaviour reflects for large times,even on compact sets,the complexity of the initial data at infinity.

  4. Confidence bounds of recurrence-based complexity measures

    Energy Technology Data Exchange (ETDEWEB)

    Schinkel, Stefan [Interdisciplinary Centre for Dynamics of Complex Systems, University of Potsdam (Germany)], E-mail: schinkel@agnld.uni-potsdam.de; Marwan, N. [Interdisciplinary Centre for Dynamics of Complex Systems, University of Potsdam (Germany); Potsdam Institute for Climate Impact Research (PIK) (Germany); Dimigen, O. [Department of Psychology, University of Potsdam (Germany); Kurths, J. [Potsdam Institute for Climate Impact Research (PIK) (Germany); Department of Physics, Humboldt University at Berlin (Germany)

    2009-06-15

    In the recent past, recurrence quantification analysis (RQA) has gained an increasing interest in various research areas. The complexity measures the RQA provides have been useful in describing and analysing a broad range of data. It is known to be rather robust to noise and nonstationarities. Yet, one key question in empirical research concerns the confidence bounds of measured data. In the present Letter we suggest a method for estimating the confidence bounds of recurrence-based complexity measures. We study the applicability of the suggested method with model and real-life data.

  5. Bloch spaces on bounded symmetric domains in complex Banach spaces

    Institute of Scientific and Technical Information of China (English)

    DENG; Fangwen

    2006-01-01

    We give a definition of Bloch space on bounded symmetric domains in arbitrary complex Banach space and prove such function space is a Banach space. The properties such as boundedness, compactness and closed range of composition operators on such Bloch space are studied.

  6. Lower Bounds on Query Complexity for Testing Bounded-Degree CSPs

    CERN Document Server

    Yoshida, Yuichi

    2010-01-01

    In this paper, we consider lower bounds on the query complexity for testing CSPs in the bounded-degree model. First, for any ``symmetric'' predicate $P:{0,1}^{k} \\to {0,1}$ except \\equ where $k\\geq 3$, we show that every (randomized) algorithm that distinguishes satisfiable instances of CSP(P) from instances $(|P^{-1}(0)|/2^k-\\epsilon)$-far from satisfiability requires $\\Omega(n^{1/2+\\delta})$ queries where $n$ is the number of variables and $\\delta>0$ is a constant that depends on $P$ and $\\epsilon$. This breaks a natural lower bound $\\Omega(n^{1/2})$, which is obtained by the birthday paradox. We also show that every one-sided error tester requires $\\Omega(n)$ queries for such $P$. These results are hereditary in the sense that the same results hold for any predicate $Q$ such that $P^{-1}(1) \\subseteq Q^{-1}(1)$. For EQU, we give a one-sided error tester whose query complexity is $\\tilde{O}(n^{1/2})$. Also, for 2-XOR (or, equivalently E2LIN2), we show an $\\Omega(n^{1/2+\\delta})$ lower bound for distinguishi...

  7. Weakly bound systems in the case of complex potentials

    International Nuclear Information System (INIS)

    We consider weakly bound two-body systems. We study the behavior of the ground state mean square radius as the binding energy tends to zero in the case of complex potentials. We show that the asymptotic law, obtained with real potentials, is modified by the occurrence of a finite width in the case of finite-range potentials. The case of the PT-symmetric potentials is also discussed. We complete our study with few remarks concerning the same problem for three weakly bound particles. (author)

  8. Basis Reduction, and the Complexity of Branch-and-Bound

    OpenAIRE

    Pataki, Gabor; Tural, Mustafa

    2009-01-01

    The classical branch-and-bound algorithm for the integer feasibility problem has exponential worst case complexity. We prove that it is surprisingly efficient on reformulated problems, in which the columns of the constraint matrix are short, and near orthogonal, i.e. a reduced basis of the generated lattice; when the entries of A (the dense part of the constraint matrix) are from {1, ..., M} for a large enough M, branch-and-bound solves almost all reformulated instances at the rootnode. We al...

  9. Moessbauer spectroscopic study of polymer-bound heme complexes

    International Nuclear Information System (INIS)

    Moessbauer spectra were measured on the heme complexes of poly(1-vinyl- and 1-vinyl-2-methylimidazole)(PVI and PMI) and heme derivatives with covalently bound imidazoleligand (IH) and 2-methylimidazole-ligand (MIH) embedded in poly(1-vinyl-2-pyrrolidone) film. Quadrupole splitting (ΔE sub(Q)) for the carbon monoxide adduct of PMI-heme indicated large electronic field gradient at the iron nucleus, probably due to steric hindrance of the polymer chain, and this behavior agreed with its low affinity with carbon monoxide. PMI-heme formed an oxygen adduct and its isomer shift and ΔE sub(Q) values were obtained. (author)

  10. Number theoretic methods in cryptography complexity lower bounds

    CERN Document Server

    Shparlinski, Igor

    1999-01-01

    The book introduces new techniques which imply rigorous lower bounds on the complexity of some number theoretic and cryptographic problems. These methods and techniques are based on bounds of character sums and numbers of solutions of some polynomial equations over finite fields and residue rings. It also contains a number of open problems and proposals for further research. We obtain several lower bounds, exponential in terms of logp, on the de­ grees and orders of • polynomials; • algebraic functions; • Boolean functions; • linear recurring sequences; coinciding with values of the discrete logarithm modulo a prime p at suf­ ficiently many points (the number of points can be as small as pI/He). These functions are considered over the residue ring modulo p and over the residue ring modulo an arbitrary divisor d of p - 1. The case of d = 2 is of special interest since it corresponds to the representation of the right­ most bit of the discrete logarithm and defines whether the argument is a quadratic...

  11. The center for plant and microbial complex carbohydrates at the University of Georgia Complex Carbohydrate Research Center. Five-year report, September 15, 1987--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, Peter; Darvill, Alan

    1992-05-01

    The Complex Carbohydrate Research Center (CCRC) is the home of ten independent but complementary interdisciplinary research groups led by nine regular faculty and one adjunct faculty. The research of these groups represents a broad spectrum of interests, and they are involved in about 90 collaborations with their CCRC and UGA colleagues and with scientists at other institutions and companies in the US, Canada, Europe, Israel, and Japan. The hallmark of the CCRC is the collaborative, interactive environment encouraged by its directors, faculty and tong-term staff. Newcomers to the CCRC or short-term members soon learn that everyone benefits from this process. The team-oriented approach in carbohydrate science translates into the day-today generous giving of one's time and expertise to the work of others, whether it be in sharing specialized instrumentation, participating in the design of experiments and interpretalon of data, providing service to scientists outside the CCRC, or joining collaborative projects. The CCRC is founded on the principle that the cross-fertilization of ideas and know-how leads to the synergistic advancement of science. This report contains a series of appendices that document the extent and breadth of the Plant and Microbial Carbohydrate Center's contributions to collaborative research and education. Several collaborative research projects that have received postdoctoral research associate support from the Grant are highlighted, as these projects are particularly illustrative of the wide-ranging collaborations that have evolved as a result of this Grant and the quality of the science that the Grant enables.

  12. Quantum multiparty communication complexity and circuit lower bounds

    CERN Document Server

    Kerenidis, I

    2005-01-01

    We define a quantum model for multiparty communication complexity and prove a simulation theorem between the classical and quantum models. As a result of our simulation, we show that if the quantum k-party communication complexity of a function f is $\\Omega(n/2^k)$, then its classical k-party communication is $\\Omega(n/2^{k/2})$. Finding such an f would allow us to prove strong classical lower bounds for (k>log n) players and hence resolve a main open question about symmetric circuits. Furthermore, we prove that for the Generalized Inner Product (GIP) function, the quantum model is exponentially more efficient than the classical one. This provides the first exponential separation for a total function between any quantum and public coin randomized communication model.

  13. Neodymium(III) Complexation by Amino-Carbohydrates via a Ligand-Controlled Hydrolysis Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Levitskaia, Tatiana G.; Chen, Yongsheng; Fulton, John L.; Sinkov, Sergey I.

    2011-07-28

    Chelation of neodymium-III Nd(III) by D-glucosamine (DGA) and chitosan was investigated in solution at near-physiological pH and ionic strength. This research demonstrates the first example of the lanthanide ion heteroleptic hydroxo-carbohydrate complex in solution. It was demonstrated that DGA and chitosan suppressed formation of polynuclear Nd(III) species at elevated pH.

  14. Protein-carbohydrate complex reveals circulating metastatic cells in a microfluidic assay

    KAUST Repository

    Simone, Giuseppina

    2013-02-11

    Advances in carbohydrate sequencing technologies reveal the tremendous complexity of the glycome and the role that glycomics might have to bring insight into the biological functions. Carbohydrate-protein interactions, in particular, are known to be crucial to most mammalian physiological processes as mediators of cell adhesion and metastasis, signal transducers, and organizers of protein interactions. An assay is developed here to mimic the multivalency of biological complexes that selectively and sensitively detect carbohydrate-protein interactions. The binding of β-galactosides and galectin-3 - a protein that is correlated to the progress of tumor and metastasis - is examined. The efficiency of the assay is related to the expression of the receptor while anchoring to the interaction\\'s strength. Comparative binding experiments reveal molecular binding preferences. This study establishes that the assay is robust to isolate metastatic cells from colon affected patients and paves the way to personalized medicine. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Influence of Grape Maturity on Complex Carbohydrate Composition of Red Sparkling Wines.

    Science.gov (United States)

    Martínez-Lapuente, Leticia; Apolinar-Valiente, Rafael; Guadalupe, Zenaida; Ayestarán, Belén; Pérez-Magariño, Silvia; Williams, Pascale; Doco, Thierry

    2016-06-22

    This paper studied how grape maturity affected complex carbohydrate composition during red sparkling wine making and wine aging. Grape ripening stage (premature and mature grapes) showed a significant impact on the content, composition, and evolution of polysaccharides and oligosaccharides of sparkling wines. Polysaccharides rich in arabinose and galactose, mannoproteins, rhamnogalacturonans II, and oligosaccharides in base wines increased with maturity. For both maturity stages, polysaccharides rich in arabinose and galactose, and the glucuronic acid glycosyl residue of the oligosaccharides were the major carbohydrates detected in all vinification stages. The total glycosyl content of oligosaccharides decreased during the whole period of aging on yeast lees. The reduction of polysaccharides rich in arabinose and galactose and rhamnogalacturonans type II during the aging was more pronounced in mature samples. To our knowledge, this is the first report of the polysaccharide and oligosaccharide composition of red sparkling wines. PMID:27226011

  16. Enzymatic degradation of lignin‐carbohydrate complexes (LCCs): Model studies using a fungal glucuronoyl esterase from Cerrena unicolor

    DEFF Research Database (Denmark)

    d'Errico, Clotilde; Jørgensen, Jonas O.; Krogh, Kristian B. R. M.;

    2015-01-01

    Lignin‐carbohydrate complexes (LCCs) are believed to influence the recalcitrance of lignocellulosic plant material preventing optimal utilization of biomass in e.g. forestry, feed and biofuel applications. The recently emerged carbohydrate esterase (CE) 15 family of glucuronoyl esterases (GEs) ha...... provide a valuable tool for the screening, selection and development of industrially relevant GEs for delignification of biomass. Biotechnol. Bioeng. 2015;112: 914–922. © 2014 Wiley Periodicals, Inc....

  17. The center for plant and microbial complex carbohydrates at the University of Georgia Complex Carbohydrate Research Center. Annual report, September 15, 1990--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, P.; Darvill, A.

    1991-08-01

    Research from the Complex Carbohydrates Research Center at the University of Georgia is presented. Topics include: Structural determination of soybean isoflavones which specifically induce Bradyrhizobium japonicum nodD1 but not the nodYABCSUIJ operon; structural analysis of the lipopolysaccharides (LPSs) from symbiotic mutants of Bradyrhizobium japonicum; structural characterization of lipooligosaccharides from Bradyrhizobium japonicum that are required for the specific nodulation of soybean; structural characterization of the LPSs from R. Leguminosarum biovar phaseoli, the symbiont of bean; characterization of bacteroid-specific LPS epitopes in R. leguminosarum biovar viciae; analysis of the surface polysaccharides of Rhizobium meliloti mutants whose lipopolysaccharides and extracellular polysaccharides can have the same function in symbiosis; characterization of a polysaccharide produced by certain Bradyrhizobium japonicum strains within soybean nodules; structural analysis of a streptococcal adhesin polysaccharide receptor; conformational studies of xyloglucan, the role of the fucosylated side chain in surface-specific cellulose-xyloglucan interactions; the structure of an acylated glucosamine oligosaccharide signal molecule (nod factor) involved in the symbiosis of Rhizobium leguminosarum biovar viciae with its host Vicia sativa; investigating membrane responses induced by oligogalacturonides in cultured cells; the polygalacturonase inhibitor protein; characterization of the self-incompatability glycoproteins from Petunia hybrida; investigation of the cell wall polysaccharide structures of Arabidopsis thaliana; and the glucan inhibition of virus infection of tabacco.

  18. Histochemical characterisation of complex carbohydrates expressed in the alimentary tract of chickens.

    Science.gov (United States)

    Scocco, Paola; Pedini, Vera

    2010-08-01

    This study characterised the composition of surface and secretion complex carbohydrates in the alimentary tract of organically and intensively housed chickens. Histochemical labelling was carried out on samples of oesophagus, glandular stomach and proximal duodenum using (1) alcian blue (AB) at pH 2.5 combined with neuraminidase digestion (Sial) with or without saponification (KOH), (2) AB at pH 1 and 0.5, (3) periodic acid-Schiff (PAS), (4) a combined AB-PAS stain, and (5) both low and high iron diamine stains combined with enzymatic treatments specific for glycosaminoglycans. Semi-quantitative scoring of the histochemical staining indicated abundant acidic sulfated glycoconjugates in each alimentary tract region, in addition to the presence of sialoglycoderivatives in the oesophagus. These complex carbohydrate components are likely to have various functions including the provision of a protective visco-elastic barrier and a role in the defence against specific pathogens. The findings provide a starting point for a more in-depth study of alimentary tract glycoconjugates in poultry. PMID:19477664

  19. Bounds on Average Time Complexity of Decision Trees

    KAUST Repository

    Chikalov, Igor

    2011-01-01

    In this chapter, bounds on the average depth and the average weighted depth of decision trees are considered. Similar problems are studied in search theory [1], coding theory [77], design and analysis of algorithms (e.g., sorting) [38]. For any diagnostic problem, the minimum average depth of decision tree is bounded from below by the entropy of probability distribution (with a multiplier 1/log2 k for a problem over a k-valued information system). Among diagnostic problems, the problems with a complete set of attributes have the lowest minimum average depth of decision trees (e.g, the problem of building optimal prefix code [1] and a blood test study in assumption that exactly one patient is ill [23]). For such problems, the minimum average depth of decision tree exceeds the lower bound by at most one. The minimum average depth reaches the maximum on the problems in which each attribute is "indispensable" [44] (e.g., a diagnostic problem with n attributes and kn pairwise different rows in the decision table and the problem of implementing the modulo 2 summation function). These problems have the minimum average depth of decision tree equal to the number of attributes in the problem description. © Springer-Verlag Berlin Heidelberg 2011.

  20. Lower bounds on information complexity via zero-communication protocols and applications

    CERN Document Server

    Kerenidis, Iordanis; Lerays, Virginie; Roland, Jeremie; Xiao, David

    2012-01-01

    We show that almost all known lower bound methods for communication complexity are also lower bounds for the information complexity. In particular, we define a relaxed version of the partition bound of Jain and Klauck and prove that it lower bounds the information complexity of any function. Our relaxed partition bound subsumes all norm based methods (e.g. the factorization norm method) and rectangle-based methods (e.g. the rectangle/corruption bound, the smooth rectangle bound, and the discrepancy bound), except the partition bound. Our result uses a new connection between rectangles and zero-communication protocols where the players can either output a value or abort. We prove the following compression lemma: given a protocol for a function f with information complexity I, one can construct a zero-communication protocol that has non-abort probability at least 2^{-O(I)} and that computes f correctly with high probability conditioned on not aborting. Then, we show how such a zero-communication protocol relate...

  1. A complexity lower bound based on software engineering concepts

    OpenAIRE

    Rojas Paredes, Andrés

    2013-01-01

    We consider the problem of polynomial equation solving also known as quantifier elimination in Effective Algebraic Geometry. The complexity of the first elimination algorithms were double exponential, but a considerable progress was carried out when the polynomials were represented by arithmetic circuits evaluating them. This representation improves the complexity to pseudo–polynomial time. The question is whether the actual asymptotic complexity of circuit– based elimination algorithms ma...

  2. Biosynthesis of the carbohydrate moieties of arabinogalactan proteins by membrane-bound β-glucuronosyltransferases from radish primary roots.

    Science.gov (United States)

    Endo, Maya; Kotake, Toshihisa; Watanabe, Yoko; Kimura, Kazumasa; Tsumuraya, Yoichi

    2013-12-01

    A membrane fraction from etiolated 6-day-old primary radish roots (Raphanus sativus L. var hortensis) contained β-glucuronosyltransferases (GlcATs) involved in the synthesis of the carbohydrate moieties of arabinogalactan proteins (AGPs). The GlcATs transferred [(14)C]GlcA from UDP-[(14)C]GlcA on to β-(1 → 3)-galactan as an exogenous acceptor substrate, giving a specific activity of 50-150 pmol min(-1) (mg protein)(-1). The enzyme specimen also catalyzed the transfer of [(14)C]GlcA on to an enzymatically modified AGP from mature radish root. Analysis of the transfer products revealed that the transfer of [(14)C]GlcA occurred preferentially on to consecutive (1 → 3)-linked β-Gal chains as well as single branched β-(1 → 6)-Gal residues through β-(1 → 6) linkages, producing branched acidic side chains. The enzymes also transferred [(14)C]GlcA residues on to several oligosaccharides, such as β-(1 → 6)- and β-(1 → 3)-galactotrioses. A trisaccharide, α-L-Araf-(1 → 3)-β-Gal-(1 → 6)-Gal, was a good acceptor, yielding a branched tetrasaccharide, α-L-Araf-(1 → 3)[β-GlcA-(1 → 6)]-β-Gal-(1 → 6)-Gal. We report the first in vitro assay system for β-GlcATs involved in the AG synthesis as a step toward full characterization and cloning. PMID:24057431

  3. Lower Bounds for Number-in-Hand Multiparty Communication Complexity, Made Easy

    DEFF Research Database (Denmark)

    Phillips, Jeff; Verbin, Elad; Zhang, Qin

    2012-01-01

    In this paper we prove lower bounds on randomized multiparty communication complexity, both in the blackboard model (where each message is written on a blackboard for all players to see) and (mainly) in the message-passing model, where messages are sent player-to-player. We introduce a new...... technique for proving such bounds, called symmetrization, which is natural, intuitive, and often easy to use. For example, for the problem where each of k players gets a bit-vector of length n, and the goal is to compute the coordinate-wise XOR of these vectors, we prove a tight lower bounds of Ω(nk) in the...... technique seems applicable to a wide range of other problems as well. The obtained communication lower bounds imply new lower bounds in the functional monitoring model [11] (also called the distributed streaming model). All of our lower bounds allow randomized communication protocols with two-sided error...

  4. Limitations of Lower-Bound Methods for the Wire Complexity of Boolean Operators

    OpenAIRE

    Drucker, Andrew

    2012-01-01

    We study the circuit complexity of Boolean operators, i.e., collections of Boolean functions defined over a common input. Our focus is the well-studied model in which arbitrary Boolean functions are allowed as gates, and in which a circuit's complexity is measured by its depth and number of wires. We show sharp limitations of several existing lower-bound methods for this model. First, we study an information-theoretic lower-bound method due to Cherukhin, that yields bounds of form $\\Omega_d(n...

  5. Complex carbohydrates in the dietary management of patients with glycogenosis caused by glucose-6-phosphatase deficiency.

    Science.gov (United States)

    Smit, G P; Ververs, M T; Belderok, B; Van Rijn, M; Berger, R; Fernandes, J

    1988-07-01

    Carbohydrates with digestion characteristics between those of lente uncooked starches and rapidly digestible oligosaccharides were administered in a dose of 1.5 g/kg body weight to five patients with glycogenosis from glucose-6-phosphatase deficiency. Postprandial duration of normoglycemia and concentrations of blood insulin and lactate were determined. Uncooked barley groats in water, or incorporated in a meal turned out to behave as lente carbohydrates. Uncooked couscous in water, couscous incorporated in a meal, and partially cooked macaroni given as a meal behaved as semilente carbohydrates as compared with uncooked cornstarch and glucose. The in vitro determination of the digestibility index along with the in vivo tolerance test enables us to choose and incorporate semilente carbohydrates in the day-time treatment of patients. PMID:3291600

  6. Without bounds a scientific canvas of nonlinearity and complex dynamics

    CERN Document Server

    Ryazantsev, Yuri; Starov, Victor; Huang, Guo-Xiang; Chetverikov, Alexander; Arena, Paolo; Nepomnyashchy, Alex; Ferrus, Alberto; Morozov, Eugene

    2013-01-01

    Bringing together over fifty contributions on all aspects of nonlinear and complex dynamics, this impressive topical collection is both a scientific and personal tribute, on the occasion of his 70th birthday, by many outstanding colleagues in the broad fields of research pursued by Prof. Manuel G Velarde. The topics selected reflect the research areas covered by the famous Instituto Pluridisciplinar at the Universidad Complutense of Madrid, which he co-founded over two decades ago, and include: fluid physics and related nonlinear phenomena at interfaces and in other geometries, wetting and spreading dynamics, geophysical and astrophysical flows, and novel aspects of electronic transport in anharmonic lattices, as well as topics in neurodynamics and robotics.

  7. A method for deriving lower bounds for the complexity of monotone arithmetic circuits computing real polynomials

    International Nuclear Information System (INIS)

    This work suggests a method for deriving lower bounds for the complexity of polynomials with positive real coefficients implemented by circuits of functional elements over the monotone arithmetic basis {x+y, x · y} ∪ {a · x | a ∈ R+}. Using this method, several new results are obtained. In particular, we construct examples of polynomials of degree m-1 in each of the n variables with coefficients 0 and 1 having additive monotone complexity m(1-o(1))n and multiplicative monotone complexity m(1/2-o(1))n as mn→∞. In this form, the lower bounds derived here are sharp. Bibliography: 72 titles.

  8. Control of Future Air Traffic Systems via Complexity Bound Management

    Science.gov (United States)

    Alexandrov, Natalia

    2013-01-01

    The complexity of the present system for managing air traffic has led to "discreteness" in approaches to creating new concepts: new concepts are created as point designs, based on experience, expertise, and creativity of the proposer. Discrete point designs may be highly successful but they are difficult to substantiate in the face of equally strong substantiation of competing concepts, as well as the state of the art in concept evaluation via simulations. Hybrid concepts may present a compromise - the golden middle. Yet a hybrid of sometimes in principle incompatible concepts forms another point design that faces the challenge of substantiation and validation. We are faced with the need to re-design the air transportation system ab initio. This is a daunting task, especially considering the problem of transitioning from the present system to any fundamentally new system. However, design from scratch is also an opportunity to reconsider approaches to new concept development. In this position paper we propose an approach, Optimized Parametric Functional Design, for systematic development of concepts for management and control of airspace systems, based on optimization formulations in terms of required system functions and states. This reasoning framework, realizable in the context of ab initio system design, offers an approach to deriving substantiated airspace management and control concepts. With growing computational power, we hope that the approach will also yield a methodology for actual dynamic control of airspace

  9. Influence of the π-coordinated arene on the anticancer activity of ruthenium(II carbohydrate organometallic complexes

    Directory of Open Access Journals (Sweden)

    Muhammad eHanif

    2013-10-01

    Full Text Available The synthesis and in vitro cytotoxicity of a series of RuII(arene complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well with cellular accumulation. The most lipophilic compound bearing a biphenyl moiety and a cyclohexylidene-protected carbohydrate is the most cytotoxic with unprecedented IC50 values for the compound class in three human cancer cell lines. This compound shows reactivity to the DNA model nucleobase 9-ethylguanine, but does not alter the secondary structure of plasmid DNA indicating that other biological targets are responsible for its cytotoxic effect.

  10. Carbohydrates in Supramolecular Chemistry.

    Science.gov (United States)

    Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

    2016-02-24

    Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed. PMID:26702928

  11. Counting carbohydrates

    Science.gov (United States)

    Carb counting; Carbohydrate-controlled diet; Diabetic diet; Diabetes-counting carbohydrates ... goal is not to limit carbohydrates in the diet completely, but to make ... with diabetes can better control their blood sugar if they ...

  12. Mild and rational synthesis of palladium complexes comprising C(4)-bound N-heterocyclic carbenes

    OpenAIRE

    Kluser, Evelyne; Neels, Antonia; Albrecht, Martin

    2007-01-01

    Oxidative addition of pyridyl-functionalised 4-iodoimidazolium salts to palladium(0) gives catalytically active complexes in which the N-heterocyclic carbene is bound to the palladium(II) centre in a non-classical bonding mode via C(4).

  13. Lower Bounds on Quantum Query Complexity for Read-Once Formulas with XOR and MUX Operators

    Science.gov (United States)

    Fukuhara, Hideaki; Takimoto, Eiji

    We introduce a complexity measure r for the class F of read-once formulas over the basis {AND, OR, NOT, XOR, MUX} and show that for any Boolean formula F in the class F, r(F) is a lower bound on the quantum query complexity of the Boolean function that F represents. We also show that for any Boolean function f represented by a formula in F, the deterministic query complexity of f is only quadratically larger than the quantum query complexity of f. Thus, the paper gives further evidence for the conjecture that there is an only quadratic gap for all functions.

  14. A Goppa-like bound on the trellis state complexity of algebraic geometric codes

    OpenAIRE

    Munuera, Carlos; Torres, Fernando

    2002-01-01

    For a linear code $\\cC$ of length $n$ and dimension $k$, Wolf noticed that the trellis state complexity $s(\\cC)$ of $\\cC$ is upper bounded by $w(\\cC):=\\min(k,n-k)$. In this paper we point out some new lower bounds for $s(\\cC)$. In particular, if $\\cC$ is an Algebraic Geometric code, then $s(\\cC)\\geq w(\\cC)-(g-a)$, where $g$ is the genus of the underlying curve and $a$ is the abundance of the code.

  15. Cryptographic applications of analytic number theory complexity lower bounds and pseudorandomness

    CERN Document Server

    2003-01-01

    The book introduces new ways of using analytic number theory in cryptography and related areas, such as complexity theory and pseudorandom number generation. Key topics and features: - various lower bounds on the complexity of some number theoretic and cryptographic problems, associated with classical schemes such as RSA, Diffie-Hellman, DSA as well as with relatively new schemes like XTR and NTRU - a series of very recent results about certain important characteristics (period, distribution, linear complexity) of several commonly used pseudorandom number generators, such as the RSA generator, Blum-Blum-Shub generator, Naor-Reingold generator, inversive generator, and others - one of the principal tools is bounds of exponential sums, which are combined with other number theoretic methods such as lattice reduction and sieving - a number of open problems of different level of difficulty and proposals for further research - an extensive and up-to-date bibliography Cryptographers and number theorists will find th...

  16. Carbon dioxide is tightly bound in the [Co(Pyridine)(CO2)]− anionic complex

    International Nuclear Information System (INIS)

    The [Co(Pyridine)(CO2)]− anionic complex was studied through the combination of photoelectron spectroscopy and density functional theory calculations. This complex was envisioned as a primitive model system for studying CO2 binding to negatively charged sites in metal organic frameworks. The vertical detachment energy (VDE) measured via the photoelectron spectrum is 2.7 eV. Our calculations imply a structure for [Co(Pyridine)(CO2)]− in which a central cobalt atom is bound to pyridine and CO2 moieties on either sides. This structure was validated by acceptable agreement between the calculated and measured VDE values. Based on our calculations, we found CO2 to be bound within the anionic complex by 1.4 eV

  17. A Trichotomy Theorem for the Approximate Counting of Complex-Weighted Bounded-Degree Boolean CSPs

    CERN Document Server

    Yamakami, Tomoyuki

    2010-01-01

    We determine the complexity of approximate counting of the total weight of assignments for complex-weighted Boolean constraint satisfaction problems (or CSPs), particularly, when degrees of instances are bounded from above by a given constant, provided that all arity-1 constraints are freely available. All degree-1 counting CSPs are solvable in polynomial time. When the degree is more than 2, we present a trichotomy theorem that classifies all bounded-degree counting CSPs into only three categories with a help of free arity-1 constraints. This classification extends to complex-weighted problems an earlier result of Dyer, Goldberg, Jalsenius, and Richerby (2010) on the complexity of the approximate counting of bounded-degree unweighted Boolean CSPs. The framework of the proof of our trichotomy theorem is based on a theory of signatures (Cai and Lu, 2007, 2008) used in Valiant's holographic algorithms. Despite the use of arbitrary complex-weight, our proof is rather elementary and intuitive by an extensive use ...

  18. Separation of galactoglucomannans, lignin, and lignin-carbohydrate complexes from hot-water-extracted Norway spruce by cross-flow filtration and adsorption chromatography

    OpenAIRE

    Niklas Westerberg; Hampus Sunner; Mikaela Helander; Gunnar Henriksson; Martin Lawoko; Anders Rasmuson

    2012-01-01

    A simple method to simultaneously recover polymeric carbohydrates, mainly galactoglucomannans (GGM), lignin, and lignin-carbohydrate complex (LCC) from hot-water-extracted Norway spruce wood is presented. The isolation method consists of cross-flow filtration, where high and low molecular mass species are removed, followed by fixed-bed adsorption on a hydrophobic polymeric resin (XAD-16) to remove lignins and lignans. In the second step of fixed-bed adsorption, a phenylic reversed-phase analy...

  19. Assemblies composed of oligothiophene–ruthenium complexes bound to CdSe nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bair, Nathan; Hancock, Jared M.; Simonson, Cameron J. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Thalman, Scott W.; Colton, John S. [Department of Physics and Astronomy,Brigham Young University, Provo, UT 84602 (United States); Asplund, Matthew C. [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Harrison, Roger G., E-mail: roger_harrison@byu.edu [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States)

    2015-02-15

    Molecular conjugates are important to link light sensitized materials to electron acceptors. We have synthesized oligothiophenes and oligothiophene–ruthenium complexes and bound them to CdSe nanoparticles. The absorption and fluorescence properties of the oligothiophenes bound to CdSe were measured. Steady-state luminescence and time correlated single photon counting were used to observe the effects on fluorescence and fluorescence lifetimes before and after binding. It was found that fluorescence of CdSe nanoparticles was quenched when they were bound to the oligothiophenes, and that the fluorescence of the oligothiophenes was also quenched. The fluorescence lifetimes of the quenched species were shortened and suggest electron transfer from oligothiophene to nanoparticle is on the order of one nanosecond. Orbital energy calculations predict that the Ru bound oligothiophenes have HOMO–LUMO energies of correct energy to allow electron and hole transfer. These experiments show that the oligothiophenes efficiently transfer optical energy between CdSe nanoparticles and could potentially be used as charge transfer junctions. - Highlights: • Ru bound thiophenes attached to CdSe nanoparticles. • Luminescence quenching of CdSe nanoparticles. • Molecular conjugates for photosensitized materials.

  20. Computing n-dimensional volumes of complexes: Application to constructive entropy bounds

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.; Makaruk, H.E.

    1997-11-01

    The constructive bounds on the needed number-of-bits (entropy) for solving a dichotomy (i.e., classification of a given data-set into two distinct classes) can be represented by the quotient of two multidimensional solid volumes. Exact methods for the calculation of the volume of the solids lead to a tighter lower bound on the needed number-of-bits--than the ones previously known. Establishing such bounds is very important for engineering applications, as they can improve certain constructive neural learning algorithms, while also reducing the area of future VLSI implementations of neural networks. The paper will present an effective method for the exact calculation of the volume of any n-dimensional complex. The method uses a divide-and-conquer approach by: (i) partitioning (i.e., slicing) a complex into simplices; and (ii) computing the volumes of these simplices. The slicing of any complex into a sum of simplices always exists, but it is not unique. This non-uniqueness gives us the freedom to choose that specific partitioning which is convenient for a particular case. It will be shown that this optimal choice is related to the symmetries of the complex, and can significantly reduce the computations involved.

  1. Valence and diffuse-bound anions of noble-gas complexes with uracil

    Science.gov (United States)

    Streit, Lívia; Dolgounitcheva, O.; Zakrzewski, V. G.; Ortiz, J. V.

    2012-11-01

    Valence-bound (VB) and diffuse-bound (DB) anions of noble-gas (Ar, Kr, and Xe) complexes with uracil have been studied with ab initio methods. MP2 optimizations revealed minima corresponding to anions of both kinds in each case. Coupled-cluster singles and doubles with perturbative triples, CCSD(T), and electron propagator single-point calculations were performed in order to assess vertical and adiabatic electron detachment energies of these complexes. Ab initio electron propagator calculations employed the outer valence Green's function and partial third-order approximations, and the algebraic diagrammatic construction in third order. Basis set effects have been systematically examined. DB anions of all three complexes were adiabatically bound, with calculated adiabatic electron attachment energies below 0.06 eV. Corresponding vertical electron detachment energies were below 0.1 eV. As to VB anions, only the Xe complex had a positive adiabatic electron detachment energy, of 0.01 eV, with a corresponding vertical electron detachment energy of 0.6 eV. These computational findings are consistent with the interpretation of results previously obtained experimentally by Hendricks et al.

  2. Extension of a Spectral Bounding Method to Complex Rotated Hamiltonians, with Application to $p^2-ix^3$

    OpenAIRE

    Handy, C. R.; Wang, Xiao Qian

    2001-01-01

    We show that a recently developed method for generating bounds for the discrete energy states of the non-hermitian $-ix^3$ potential (Handy 2001) is applicable to complex rotated versions of the Hamiltonian. This has important implications for extension of the method in the analysis of resonant states, Regge poles, and general bound states in the complex plane (Bender and Boettcher (1998)).

  3. Higher complexity search problems for bounded arithmetic and a formalized no-gap theorem

    Czech Academy of Sciences Publication Activity Database

    Thapen, Neil

    2011-01-01

    Roč. 50, 7-8 (2011), s. 665-680. ISSN 1432-0665 R&D Projects: GA AV ČR IAA100190902; GA MŠk LC505; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : bounded arithmetic * proof complexity * search problems Subject RIV: BA - General Mathematics Impact factor: 0.341, year: 2011 http://www.springerlink.com/content/l19kr20362065t86/

  4. A New Boundary Model for Simulating Complex and Flexible Wall Bounded Domain in Dissipative Particle Dynamics

    Directory of Open Access Journals (Sweden)

    Saeid Mokhtarian

    2014-01-01

    Full Text Available Despite extensive area of applications, simulation of complex wall bounded problems or any deformable boundary is still a challenge in a Dissipative Particle Dynamics simulation. This limitation is rooted in the soft force nature of DPD and the fact that we need to use an antipenetration model for escaped particles. In the present paper, we propose a new model of antipenetration which preserves the conservation of linear momentum on the boundaries and enables us to simulate complex and flexible boundaries. Finally by performing numerical simulations, we demonstrate the validity of our new model.

  5. The pervasive reach of resource-bounded Kolmogorov complexity in computational complexity theory

    Czech Academy of Sciences Publication Activity Database

    Allender, E.; Koucký, Michal; Ronneburger, D.; Roy, S.

    2011-01-01

    Roč. 77, č. 1 (2011), s. 14-40. ISSN 0022-0000 R&D Projects: GA ČR GAP202/10/0854; GA MŠk(CZ) 1M0545; GA AV ČR IAA100190902 Institutional research plan: CEZ:AV0Z10190503 Keywords : Circuit complexity * Distinguishing complexity * FewEXP * Formula size * Kolmogorov complexity Subject RIV: BA - General Mathematics Impact factor: 1.157, year: 2011 http://www.sciencedirect.com/science/article/pii/S0022000010000887

  6. Bounds on the sample complexity for private learning and private data release

    Energy Technology Data Exchange (ETDEWEB)

    Kasiviswanathan, Shiva [Los Alamos National Laboratory; Beime, Amos [BEN-GURION UNIV.; Nissim, Kobbi [BEN-GURION UNIV.

    2009-01-01

    Learning is a task that generalizes many of the analyses that are applied to collections of data, and in particular, collections of sensitive individual information. Hence, it is natural to ask what can be learned while preserving individual privacy. [Kasiviswanathan, Lee, Nissim, Raskhodnikova, and Smith; FOCS 2008] initiated such a discussion. They formalized the notion of private learning, as a combination of PAC learning and differential privacy, and investigated what concept classes can be learned privately. Somewhat surprisingly, they showed that, ignoring time complexity, every PAC learning task could be performed privately with polynomially many samples, and in many natural cases this could even be done in polynomial time. While these results seem to equate non-private and private learning, there is still a significant gap: the sample complexity of (non-private) PAC learning is crisply characterized in terms of the VC-dimension of the concept class, whereas this relationship is lost in the constructions of private learners, which exhibit, generally, a higher sample complexity. Looking into this gap, we examine several private learning tasks and give tight bounds on their sample complexity. In particular, we show strong separations between sample complexities of proper and improper private learners (such separation does not exist for non-private learners), and between sample complexities of efficient and inefficient proper private learners. Our results show that VC-dimension is not the right measure for characterizing the sample complexity of proper private learning. We also examine the task of private data release (as initiated by [Blum, Ligett, and Roth; STOC 2008]), and give new lower bounds on the sample complexity. Our results show that the logarithmic dependence on size of the instance space is essential for private data release.

  7. Micro-Spectroscopic Imaging of Lignin-Carbohydrate Complexes in Plant Cell Walls and Their Migration During Biomass Pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yining; Zhao, Shuai; Wei, Hui; Tucker, Melvin P.; Johnson, David K.; Himmel, Michael E.; Mosier, Nathan S.; Meilan, Richard; Ding, Shi-You

    2015-04-27

    In lignocellulosic biomass, lignin is the second most abundant biopolymer. In plant cell walls, lignin is associated with polysaccharides to form lignin-carbohydrate complexes (LCC). LCC have been considered to be a major factor that negatively affects the process of deconstructing biomass to simple sugars by cellulosic enzymes. Here, we report a micro-spectroscopic approach that combines fluorescence lifetime imaging microscopy and Stimulated Raman Scattering microscopy to probe in situ lignin concentration and conformation at each cell wall layer. This technique does not require extensive sample preparation or any external labels. Using poplar as a feedstock, for example, we observe variation of LCC in untreated tracheid poplar cell walls. The redistribution of LCC at tracheid poplar cell wall layers is also investigated when the chemical linkages between lignin and hemicellulose are cleaved during pretreatment. Our study would provide new insights into further improvement of the biomass pretreatment process.

  8. The complexity of membrane-bound glycans in health and disease and the beneficial properties of glyconutrients

    OpenAIRE

    Wagner, Lynn

    2013-01-01

    The surface of all free living cells and all multicellular cell types are covered with a dense and complex array of sugars mostly attached to proteins and lipids. These specific sugars are referred to as glycans and the biological role of these sugars includes cell-cell, cell-matrix, cell-molecule interactions, and interactions between other organisms. The chemistry of carbohydrates has been studied well since the first part of the 20th century without understanding the complexity of the glyc...

  9. Three-dimensional representations of complex carbohydrates and polysaccharides--SweetUnityMol: a video game-based computer graphic software.

    Science.gov (United States)

    Pérez, Serge; Tubiana, Thibault; Imberty, Anne; Baaden, Marc

    2015-05-01

    A molecular visualization program tailored to deal with the range of 3D structures of complex carbohydrates and polysaccharides, either alone or in their interactions with other biomacromolecules, has been developed using advanced technologies elaborated by the video games industry. All the specific structural features displayed by the simplest to the most complex carbohydrate molecules have been considered and can be depicted. This concerns the monosaccharide identification and classification, conformations, location in single or multiple branched chains, depiction of secondary structural elements and the essential constituting elements in very complex structures. Particular attention was given to cope with the accepted nomenclature and pictorial representation used in glycoscience. This achievement provides a continuum between the most popular ways to depict the primary structures of complex carbohydrates to visualizing their 3D structures while giving the users many options to select the most appropriate modes of representations including new features such as those provided by the use of textures to depict some molecular properties. These developments are incorporated in a stand-alone viewer capable of displaying molecular structures, biomacromolecule surfaces and complex interactions of biomacromolecules, with powerful, artistic and illustrative rendering methods. They result in an open source software compatible with multiple platforms, i.e., Windows, MacOS and Linux operating systems, web pages, and producing publication-quality figures. The algorithms and visualization enhancements are demonstrated using a variety of carbohydrate molecules, from glycan determinants to glycoproteins and complex protein-carbohydrate interactions, as well as very complex mega-oligosaccharides and bacterial polysaccharides and multi-stranded polysaccharide architectures. PMID:25475093

  10. Quantum tomography via compressed sensing: error bounds, sample complexity and efficient estimators

    International Nuclear Information System (INIS)

    Intuitively, if a density operator has small rank, then it should be easier to estimate from experimental data, since in this case only a few eigenvectors need to be learned. We prove two complementary results that confirm this intuition. Firstly, we show that a low-rank density matrix can be estimated using fewer copies of the state, i.e. the sample complexity of tomography decreases with the rank. Secondly, we show that unknown low-rank states can be reconstructed from an incomplete set of measurements, using techniques from compressed sensing and matrix completion. These techniques use simple Pauli measurements, and their output can be certified without making any assumptions about the unknown state. In this paper, we present a new theoretical analysis of compressed tomography, based on the restricted isometry property for low-rank matrices. Using these tools, we obtain near-optimal error bounds for the realistic situation where the data contain noise due to finite statistics, and the density matrix is full-rank with decaying eigenvalues. We also obtain upper bounds on the sample complexity of compressed tomography, and almost-matching lower bounds on the sample complexity of any procedure using adaptive sequences of Pauli measurements. Using numerical simulations, we compare the performance of two compressed sensing estimators—the matrix Dantzig selector and the matrix Lasso—with standard maximum-likelihood estimation (MLE). We find that, given comparable experimental resources, the compressed sensing estimators consistently produce higher fidelity state reconstructions than MLE. In addition, the use of an incomplete set of measurements leads to faster classical processing with no loss of accuracy. Finally, we show how to certify the accuracy of a low-rank estimate using direct fidelity estimation, and describe a method for compressed quantum process tomography that works for processes with small Kraus rank and requires only Pauli eigenstate preparations

  11. Toward better formula lower bounds: an information complexity approach to the KRW composition conjecture

    Czech Academy of Sciences Publication Activity Database

    Gavinsky, Dmitry; Meir, O.; Weinstein, O.; Wigderson, A.

    New York: ACM, 2014 - (Shmoys, D.), s. 213-222 ISBN 978-1-4503-2710-7. [STOC 2014. Symposium on Theory of Computing /46./. New York (US), 31.05.2014-03.06.2014] R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : formula lower bounds * information complexity * composition conjecture Subject RIV: BA - General Mathematics http://dl.acm.org/citation.cfm?id=2591856&dl=ACM&coll=DL&CFID=454065209&CFTOKEN=54114198

  12. Pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions

    Institute of Scientific and Technical Information of China (English)

    Zou Yan-Li; Chen Guan-Rong

    2009-01-01

    This paper studies pinning-controlled synchronization of complex networks with bounded or unbounded synchro nized regions.To study a state-feedback pinning-controlled network with N nodes,it first converts the controlled network to an extended network of N+1 nodes without controls.It is shown that the controlled synchronizability of the given network is determined by the real part of the smallest nonzero eigenvalue of the coupling matrix of its extended network when the synchronized region is unbounded; but it is determined by the ratio of the real parts of the largest and the smallest nonzero eigenvalues of the coupling matrix when the synchronized region is bounded.Both theoretical analysis and numerical simulation show that the portion of controlled nodes has no critical values when the synchronized region is unbounded,but it has a critical value when the synchronized region is bounded.In the former case,therefore,it is possible to control the network to achieve synchronization by pinning only one node.In the latter ease,the network can achieve controlled synchronization only when the portion of controlled nodes is larger than the critical value.

  13. Communication: Photoactivation of nucleobase bound platinumII metal complexes: Probing the influence of the nucleobase

    International Nuclear Information System (INIS)

    We present UV laser action spectra (220-300 nm) of isolated nucleobase-bound PtII(CN)42− complexes, i.e., Pt(CN)42−⋅M, where M = uracil, thymine, cytosine, and adenine. These metal complex-nucleobase clusters represent model systems for identifying the fundamental photophysical and photochemical processes occurring in photodynamic platinum (II) drug therapies that target DNA. This is the first study to explore the specific role of the nucleobase in the photophysics of the aggregate complex. Each of the complexes studied displays a broadly similar absorption spectra, with a strong λmax ∼ 4.7 eV absorption band (nucleobase localized chromophore) and a subsequent increase in the absorption intensity towards higher spectral-energy (Pt(CN)42− localized chromophore). However, strikingly different band widths are observed across the series of complexes, decreasing in the order Pt(CN)42−⋅Thymine > Pt(CN)42−⋅Uracil > Pt(CN)42−⋅Adenine > Pt(CN)42−⋅Cytosine. Changes in the bandwidth of the ∼4.7 eV band are accompanied by distinctive changes in the photofragment product ions observed following photoexcitation, with the narrower-bandwidth complexes showing a greater propensity to decay via electron detachment decay. We discuss these observations in the context of the distinctive nucleobase-dependent excited state lifetimes

  14. Complex bounds and microstructural recovery from measurements of sea ice permittivity

    International Nuclear Information System (INIS)

    Sea ice is a porous composite of pure ice with brine, air, and salt inclusions. The polar sea ice packs play a key role in the earth's ocean-climate system, and they host robust algal and bacterial communities that support the Arctic and Antarctic ecosystems. Monitoring the sea ice packs on global or regional scales is an increasingly important problem, typically involving the interaction of an electromagnetic wave with sea ice. In the quasistatic regime where the wavelength is much longer than the composite microstructural scale, the electromagnetic behavior is characterized by the effective complex permittivity tensor ε*. In assessing the impact of climate change on the polar sea ice covers, current satellites and algorithms can predict ice extent, but the thickness distribution remains an elusive, yet most important feature. In recent years, electromagnetic induction devices using low frequency waves have been deployed on ships, helicopters and planes to obtain thickness data. Here we compare two sets of theoretical bounds to extensive outdoor tank and in situ field data on ε* at 50MHz taken in the Arctic and Antarctic. The sea ice is assumed to be a two phase composite of ice and brine with known constituent permittivities. The first set of bounds assumes only knowledge of the brine volume fraction or porosity, and the second set further assumes statistical isotropy of the microstructure. We obtain excellent agreement between theory and experiment, and are able to observe the apparent violation of the isotropic bounds as the vertically oriented microstructure becomes increasingly connected for higher porosities. Moreover, these bounds are inverted to obtain estimates of the porosity from the measurements of ε*. We find that the temporal variations of the reconstructed porosity, which is directly related to temperature, closely follow the actual behavior

  15. Heck Arylation of Acrylonitrile with Aryl Iodides Catalyzed by a Silica-bound Arsine Palladium(0) Complex

    Institute of Scientific and Technical Information of China (English)

    Ming Zhong CAI; Hong ZHAO; Rong Li ZHANG

    2005-01-01

    Acrylonitrile reacts with aryl iodides in the presence of tri-n-butylamine and a catalytic amount of a silica-bound arsine palladium(0) complex to afford stereoselectively (E)-cinnamonitriles in high yields.

  16. Effect of vitamin E on protein bound carbohydrate complexes in radiation treated oral squamous cell carcinoma patients

    International Nuclear Information System (INIS)

    Serum glycoproteins were evaluated in oral squamous cell carcinoma patients treated with radiotherapy and also the effect of vitamin E was studied. Cell surface glycoconjugates are important parameters in the detection of malignancy. Thus, the objective of the present study is to evaluate the efficacy of vitamin E on glycoproteins in oral cavity cancer patients treated with radiotherapy. The study includes 26 age and sex matched normal healthy individuals and 26 patients with squamous cell carcinoma of oral cavity. These patients were divided into two groups, one for radiotherapy alone (at a dosage of 6000 cGy in five fractions per week for a period of six weeks) and the other for radiotherapy plus vitamin E supplementation (at a dosage of 400 IU/day of vitamin E) for the entire period of radiotherapy. Levels of hexose, hexosamine, fucose and sialic acid were increased in oral squamous cell carcinoma patients and a significant decrease was observed in radiation treated patients when compared to control. The levels of glycoconjugates were significantly decreased in radiation treated patients supplemented with vitamin E. This measurement may be useful in assessing disease progression and identifying patients resistant to therapy and a possible role of vitamin E on reduction in glycoconjugate levels of radiation treated oral squamous cell carcinoma patients. (author)

  17. Carbohydrate Analysis

    Science.gov (United States)

    Bemiller, James N.

    Carbohydrates are important in foods as a major source of energy, to impart crucial textural properties, and as dietary fiber which influences physiological processes. Digestible carbohydrates, which are converted into monosaccharides, which are absorbed, provide metabolic energy. Worldwide, carbohydrates account for more than 70% of the caloric value of the human diet. It is recommended that all persons should limit calories from fat (the other significant source) to not more than 30% and that most of the carbohydrate calories should come from starch. Nondigestible polysaccharides (all those other than starch) comprise the major portion of dietary fiber (Sect. 10.5). Carbohydrates also contribute other attributes, including bulk, body, viscosity, stability to emulsions and foams, water-holding capacity, freeze-thaw stability, browning, flavors, aromas, and a range of desirable textures (from crispness to smooth, soft gels). They also provide satiety. Basic carbohydrate structures, chemistry, and terminology can be found in references (1, 2).

  18. Quasi-Bound States of the F·CH4 Complex.

    Science.gov (United States)

    Schäpers, Daniela; Manthe, Uwe

    2016-05-19

    The F + CH4 → HF + CH3 reaction is an intensively studied prototypical example of a polyatomic reaction showing an early transition state. Prereactive complexes are assumed to play an important role in the dynamics of the reaction. In this work, the long-living resonance states resulting from the formation of a metastable F·CH4 complex are investigated in detail. Full-dimensional quantum dynamics calculations employing the multiconfigurational time-dependent Hartree (MCTDH) approach and a single adiabatic potential energy surface are used to study the low-lying quasi-bound states of the F·CH4 complex for vanishing total (nuclear) angular momentum. The computed dissociation energy of the F·CH4 complex with respect to the reactant asymptote is 170 cm(-1). About 60 resonance states with energies below the reactant asymptote are found. A detailed analysis of the computed wave function of the low-lying states shows an almost free relative rotation of F and CH4 and an approximately separable F-CH4 stretching vibration. The present results are compared with transition state spectroscopy experiments which study the photodetachment spectrum of the CH4F(-) anion. PMID:26730978

  19. In-situ annotation of carbohydrate diversity, abundance, and degradability in highly complex mixtures using NMR spectroscopy

    DEFF Research Database (Denmark)

    Meier, Sebastian

    2014-01-01

    , abundance, and degradability of such short structural motifs in plant-derived carbohydrates. Assignments of carbohydrate signals for 1H–13C NMR spectra of beer, wine, and fruit juice yield up to >130 assignments in situ, i.e. in individual samples without separation or derivatization. More than 500...... structural motifs can be resolved over a concentration range of ~103 in experiments of a few hours duration. The diversity of carbohydrate units increases according to power laws at lower concentrations for both cereal and fruit-derived samples. Simple graphs resolve the smaller overall contribution of more...

  20. Catalytic activity of polymer-bound Ru(III)–EDTA complex

    Indian Academy of Sciences (India)

    Mahesh K Dalal; R N Ram

    2001-04-01

    Chloromethylated styrene–divinylbenzene copolymer was chemically modified with ethylenediaminetetraacetic acid ligand. Catalytically active polymer containing Ru(III) moieties were synthesized from this polymeric ligand. They were characterized using FTIR, UV-vis, SEM, ESR and TGA. Other physico-chemical properties such as bulk density, surface area, moisture content and swelling behaviour in different solvents were also studied. The polymer bound complex was used to study hydrogenation of 1-hexene to -hexane under mild conditions. Influence of [1-hexene], [catalyst], temperature and nature of the solvent on the rate of the reaction was investigated. A rate expression is proposed based on the observed initial rate data. Recycling efficiency of the catalyst has also been studied.

  1. Bridge Bounding: A Local Approach for Efficient Community Discovery in Complex Networks

    CERN Document Server

    Papadopoulos, Symeon; Vakali, Athena; Kompatsiaris, Yiannis; Wagner, Nadine

    2009-01-01

    The increasing importance of Web 2.0 applications during the last years has created significant interest in tools for analyzing and describing collective user activities and emerging phenomena within the Web. Network structures have been widely employed in this context for modeling users, web resources and relations between them. However, the amount of data produced by modern web systems results in networks that are of unprecedented size and complexity, and are thus hard to interpret. To this end, community detection methods attempt to uncover natural groupings of web objects by analyzing the topology of their containing network. There are numerous techniques adopting a global perspective to the community detection problem, i.e. they operate on the complete network structure, thus being computationally expensive and hard to apply in a streaming manner. In order to add a local perspective to the study of the problem, we present Bridge Bounding, a local methodology for community detection, which explores the lo...

  2. On the Minimum Degree up to Local Complementation: Bounds and Complexity

    CERN Document Server

    Javelle, Jérôme; Perdrix, Simon

    2012-01-01

    The local minimum degree of a graph is the minimum degree reached by means of a series of local complementations. In this paper, we investigate on this quantity which plays an important role in quantum computation and quantum error correcting codes. First, we show that the local minimum degree of the Paley graph of order p is greater than sqrt{p} - 3/2, which is, up to our knowledge, the highest known bound on an explicit family of graphs. Probabilistic methods allows us to derive the existence of an infinite number of graphs whose local minimum degree is linear in their order with constant 0.189 for graphs in general and 0.110 for bipartite graphs. As regards the computational complexity of the decision problem associated with the local minimum degree, we show that it is NP-complete and that there exists no k-approximation algorithm for this problem for any constant k unless P = NP.

  3. Structure of an Rrp6-RNA exosome complex bound to poly(A) RNA

    Energy Technology Data Exchange (ETDEWEB)

    Wasmuth, Elizabeth V.; Januszyk, Kurt; Lima, Christopher D. [MSKCC

    2014-08-20

    The eukaryotic RNA exosome processes and degrades RNA by directing substrates to the distributive or processive 3' to 5' exoribonuclease activities of Rrp6 or Rrp44, respectively. The non-catalytic nine-subunit exosome core (Exo9) features a prominent central channel. Although RNA can pass through the channel to engage Rrp44, it is not clear how RNA is directed to Rrp6 or whether Rrp6 uses the central channel. Here we report a 3.3 Å crystal structure of a ten-subunit RNA exosome complex from Saccharomyces cerevisiae composed of the Exo9 core and Rrp6 bound to single-stranded poly(A) RNA. The Rrp6 catalytic domain rests on top of the Exo9 S1/KH ring above the central channel, the RNA 3' end is anchored in the Rrp6 active site, and the remaining RNA traverses the S1/KH ring in an opposite orientation to that observed in a structure of a Rrp44-containing exosome complex. Solution studies with human and yeast RNA exosome complexes suggest that the RNA path to Rrp6 is conserved and dependent on the integrity of the S1/KH ring. Although path selection to Rrp6 or Rrp44 is stochastic in vitro, the fate of a particular RNA may be determined in vivo by the manner in which cofactors present RNA to the RNA exosome.

  4. Study of transient luminescence of three kinds of Ru complexes bound to DNA

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thy-mus DNA (ctDNA) has been studied by using the time-resolved spectroscopy. The results show that the luminescence is due to the radiative decay from the charge-transfer states to the ground state. By the interaction with DNA, the radia-tiveless rate of the photoexcited Ru complex molecules decreases, which results in the increase of luminescence lifetime and efficiency. The structure of the Ru com-plex has an important impact on the interaction with DNA. The [Ru(bpy)2(7-CH3-dppz)]2+ shows the longest luminescence lifetime (about 382 ns), while the [Ru(bpy)2(7-F-dppz)]2+ shows the shortest lifetime (about 65 ns). The possible origin of the luminescence dynamics is discussed.

  5. ONO-pincer ruthenium complex-bound norvaline for efficient catalytic oxidation of methoxybenzenes with hydrogen peroxide.

    Science.gov (United States)

    Yoshida, Ryota; Isozaki, Katsuhiro; Yokoi, Tomoya; Yasuda, Nobuhiro; Sadakane, Koichiro; Iwamoto, Takahiro; Takaya, Hikaru; Nakamura, Masaharu

    2016-08-21

    The enhanced catalytic activity of ruthenium complex-bound norvaline Boc-l-[Ru]Nva-OMe 1, in which the ONO-pincer ruthenium complex Ru(pydc)(terpy) 2 is tethered to the α-side chain of norvaline, has been demonstrated for the oxidation of methoxybenzenes to p-benzoquinones with a wide scope of substrates and unique chemoselectivity. PMID:27314504

  6. C-type lectin-like carbohydrate recognition of the hemolytic lectin CEL-III containing ricin-type -trefoil folds.

    Science.gov (United States)

    Hatakeyama, Tomomitsu; Unno, Hideaki; Kouzuma, Yoshiaki; Uchida, Tatsuya; Eto, Seiichiro; Hidemura, Haruki; Kato, Norihisa; Yonekura, Masami; Kusunoki, Masami

    2007-12-28

    CEL-III is a Ca(2+)-dependent hemolytic lectin, isolated from the marine invertebrate Cucumaria echinata. The three-dimensional structure of CEL-III/GalNAc and CEL-III/methyl alpha-galactoside complexes was solved by x-ray crystallographic analysis. In these complexes, five carbohydrate molecules were found to be bound to two carbohydrate-binding domains (domains 1 and 2) located in the N-terminal 2/3 portion of the polypeptide and that contained beta-trefoil folds similar to ricin B-chain. The 3-OH and 4-OH of bound carbohydrate molecules were coordinated with Ca(2+) located at the subdomains 1alpha, 1gamma, 2alpha, 2beta, and 2gamma, simultaneously forming hydrogen bond networks with nearby amino acid side chains, which is similar to carbohydrate binding in C-type lectins. The binding of carbohydrates was further stabilized by aromatic amino acid residues, such as tyrosine and tryptophan, through a stacking interaction with the hydrophobic face of carbohydrates. The importance of amino acid residues in the carbohydrate-binding sites was confirmed by the mutational analyses. The orientation of bound GalNAc and methyl alpha-galactoside was similar to the galactose moiety of lactose bound to the carbohydrate-binding site of the ricin B-chain, although the ricin B-chain does not require Ca(2+) ions for carbohydrate binding. The binding of the carbohydrates induced local structural changes in carbohydrate-binding sites in subdomains 2alpha and 2beta. Binding of GalNAc also induced a slight change in the main chain structure of domain 3, which could be related to the conformational change upon binding of specific carbohydrates to induce oligomerization of the protein. PMID:17977832

  7. Conversion of carbohydrate biomass to γ-valerolactone by using water-soluble and reusable iridium complexes in acidic aqueous media.

    Science.gov (United States)

    Deng, Jin; Wang, Yan; Pan, Tao; Xu, Qing; Guo, Qing-Xiang; Fu, Yao

    2013-07-01

    Mild-mannered manipulation: A catalytic method for the conversion of carbohydrate biomass to γ-valerolactone in acidic aqueous media has been developed. The water-soluble iridium complexes were observed to be extremely catalytically active for providing γ-valerolactone in high yields with high TONs. The homogeneous catalysts can also be recycled and reused by applying a simple phase separation process. PMID:23757330

  8. Microbial degradation of whole-grain complex carbohydrates and impact on short-chain fatty acids and health.

    Science.gov (United States)

    Bach Knudsen, Knud Erik

    2015-03-01

    Whole-grain cereals have a complex dietary fiber (DF) composition consisting of oligosaccharides (mostly fructans), resistant starch, and nonstarch polysaccharides (NSPs); the most important are arabinoxylans, mixed-linkage β(1,3; 1,4)-d-glucan (β-glucan), and cellulose and the noncarbohydrate polyphenolic ether lignin. The highest concentration of NSPs and lignin is found in the outer cell layers of the grain, and refined flour will consequently be depleted of a large proportion of insoluble DF components. The flow and composition of carbohydrates to the large intestine are directly related to the intake of DF. The type and composition of cereal DF can consequently be used to modulate the microbial composition and activity as well as the production and molar ratios of short-chain fatty acids (SCFAs). Arabinoxylans and β-glucan in whole-grain cereals and cereal ingredients have been shown to augment SCFA production, with the strongest relative effect on butyrate. When arabinoxylans were provided as a concentrate, the effect was only on total SCFA production. Increased SCFA production in the large intestine was shown by the concentration in the portal vein, whereas the impact on the concentration in peripheral blood was less because the majority of propionate and butyrate is cleared in the liver. Active microbial fermentation with increased SCFA production reduced the exposure of potentially toxic compounds to the epithelium, potentially stimulating anorectic hormones and acting as signaling molecules between the gut and the peripheral tissues. The latter can have implications for insulin sensitivity and glucose homeostasis. PMID:25770259

  9. Towards Intelligent Dynamic Deployment of Mobile Sensors in Complex Resource-Bounded Environments

    Energy Technology Data Exchange (ETDEWEB)

    Ng, B M; Hanley, W G

    2007-05-08

    Decision-making in the face of uncertainty requires an understanding of the probabilistic mechanisms that govern the complex behavior of these systems. This issue applies to many domains: financial investments, disease control, military planning and homeland security. In each of these areas, there is a practical need for efficient resource-bounded reasoning capabilities to support optimal decision-making. Specifically, given a highly complex system, with numerous random variables and their dynamic interactions, how do we monitor such a system and detect crucial events that might impact our decision making process? More importantly, how do we perform this reasoning efficiently--to an acceptable degree of accuracy in real time--when there are only limited computational power and sensory capabilities? These questions encapsulate nontrivial key issues faced by many high-profile Laboratory missions: the problem of efficient inference and dynamic sensor deployment for risk/uncertainty reduction. By leveraging solid ideas such as system decomposition into loosely coupled subsystems and smart resource allocation among these subsystems, we can parallelize inference and data acquisition for faster and improved computational performance. In this report, we propose technical approaches for developing algorithmic tools to enable future scientific and engineering endeavors to better achieve the optimal use of limited resources for maximal return of information on a complex system. The result of the proposed research effort will be an efficient reasoning framework that would enable mobile sensors to work collaboratively as teams of adaptive and responsive agents, whose joint goal is to gather useful information that would assist in the inference process.

  10. Carbohydrate microarrays

    DEFF Research Database (Denmark)

    Park, Sungjin; Gildersleeve, Jeffrey C; Blixt, Klas Ola; Shin, Injae

    2012-01-01

    In the last decade, carbohydrate microarrays have been core technologies for analyzing carbohydrate-mediated recognition events in a high-throughput fashion. A number of methods have been exploited for immobilizing glycans on the solid surface in a microarray format. This microarray-based technol......In the last decade, carbohydrate microarrays have been core technologies for analyzing carbohydrate-mediated recognition events in a high-throughput fashion. A number of methods have been exploited for immobilizing glycans on the solid surface in a microarray format. This microarray......-based technology has been widely employed for rapid analysis of the glycan binding properties of lectins and antibodies, the quantitative measurements of glycan-protein interactions, detection of cells and pathogens, identification of disease-related anti-glycan antibodies for diagnosis, and fast assessment of...

  11. A co-axially configured submillimeter spectrometer and investigations of hydrogen bound molecular complexes

    Science.gov (United States)

    McElmurry, Blake Anthony

    The development of a co-axially configured submillimeter spectrometer is reported. The spectrometer has been constructed to observe molecular complexes that exhibit non-covalent interactions with energies much less than that of a traditional covalent bond. The structure of molecular complexes such as those formed between a rare gas and a hydrogen halide, Rg:HX where Rg is a rare gas (Rg=Ne, Ar and Kr) and HX (X=F, Cl, Br and I) can be determined directly and accurately. The center of mass interaction distance, RCM, as well as the angle of the hydrogen halide is determined, along with direct evaluation of the intermolecular vibrations as well as accurate isomerization energies between the hydrogen bound and van der Waals forms. The accuracy of the frequency determination of rovibrational transitions using the submillimeter spectrometer is also evaluated by direct comparison with the state-of-the-art pulsed nozzle Fourier transform microwave spectrometer, and this accuracy is estimated to be less than 1 kHz at 300 GHz. The tunneling or geared bending vibration of a dimer of hydrogen bromide or hydrogen iodide has been investigated. The selection rules, nuclear statistics and intensity alternation for transitions observed in these dimmers, which is a consequence of interchanging two identical nuclei in the low frequency geared bending vibration of the molecular complex, are reported. Furthermore, the rotation and quadrupole coupling constants are used to determine a vibrationally averaged structure of the complex. The energy of the low frequency bending vibration can then be compared with ab initio based potential energy surfaces. A study of the multiple isomeric forms of the molecular complex OC:HI is also presented. Multiple isotopic substitutions are used to determine the relevant ground state structures and data reported evidence for an anomalous isotope effect supporting a ground state isotopic isomerization effect. All spectroscopic data that has been reported

  12. Near optimal bounds on quantum communication complexity of single-shot quantum state redistribution

    OpenAIRE

    Anshu, Anurag; Devabathini, Vamsi Krishna; Jain, Rahul

    2014-01-01

    We show near optimal bounds on the worst case quantum communication of single-shot entanglement-assisted one-way quantum communication protocols for the {\\em quantum state redistribution} task and for the sub-tasks {\\em quantum state splitting} and {\\em quantum state merging}. Our bounds are tighter than previously known best bounds for the latter two sub-tasks. A key technical tool that we use is a {\\em convex-split} lemma which may be of independent interest.

  13. NMR-based, molecular dynamics- and random walk molecular mechanics-supported study of conformational aspects of a carbohydrate ligand (Galβ1-2Galβ1-R) for an animal galectin in the free and in the bound state

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Siebert, H.-C; Gilleron, M.; Kaltner, H.; Lieth, C.-W. von der; Kozár, T.; Bovin, N.; Korchagina, E.Y.

    1996-01-01

    The binding of a carbohydrate to a lectin may affect the conformation of the ligand. To address this question for the galectin from chicken liver, the conformation of Gal@b1-R was analyzed in the free and in the galectin-bound state with 2D-ROESY- and 1D- as well as 2D-transferred NOE-experiments. A

  14. Quantum Tomography via Compressed Sensing: Error Bounds, Sample Complexity, and Efficient Estimators

    CERN Document Server

    Flammia, Steven T; Liu, Yi-Kai; Eisert, Jens

    2012-01-01

    Intuitively, if a density operator has only a few non-zero eigenvalues, then it should be easier to estimate from experimental data, since in this case only a few eigenvectors need to be learned. We exhibit two complementary ways of making this intuition precise. On the one hand, we show that the sample complexity decreases with the rank of the density operator. In other words, fewer copies of the state need to be prepared in order to estimate a low-rank density matrix. On the other hand---and maybe more surprisingly---we prove that unknown low-rank states may be reconstructed using an incomplete set of measurement settings. The method does not require any a priori assumptions about the unknown state, uses only simple Pauli measurements, and can be efficiently and unconditionally certified. Our results extend earlier work on compressed tomography, building on ideas from compressed sensing and matrix completion. Instrumental to the improved analysis are new error bounds for compressed tomography, based on the ...

  15. Crystallization and preliminary X-ray diffraction analysis of mouse galectin-4 N-terminal carbohydrate recognition domain in complex with lactose

    International Nuclear Information System (INIS)

    Mouse galectin-4 carbohydrate binding domain was overexpressed in E. coli and crystallized in the presence of lactose. The crystals belong to tetragonal space group P4212 and diffraction data were collected to 2.1 Å resolution. Galectin-4 is thought to play a role in the process of tumour conversion of cells of the alimentary tract and the breast tissue; however, its exact function remains unknown. With the aim of elucidating the structural basis of mouse galectin-4 (mGal-4) binding specificity, we have undertaken X-ray analysis of the N-terminal domain, CRD1, of mGal-4 in complex with lactose (the basic building block of known galectin-4 carbohydrate ligands). Crystals of CRD1 in complex with lactose were obtained using vapour-diffusion techniques. The crystals belong to tetragonal space group P4212 with unit-cell parameters a = 91.1, b = 91.16, c = 57.10 Å and preliminary X-ray diffraction data were collected to 3.2 Å resolution. An optimized crystallization procedure and cryocooling protocol allowed us to extend resolution to 2.1 Å. Structure refinement is currently under way; the initial electron-density maps clearly show non-protein electron density in the vicinity of the carbohydrate binding site, indicating the presence of one lactose molecule. The structure will help to improve understanding of the binding specificity and function of the potential colon cancer marker galectin-4

  16. T cell responses affected by aminopeptidase N (CD13)-mediated trimming of major histocompatibility complex class II-bound peptides

    DEFF Research Database (Denmark)

    Larsen, S L; Pedersen, L O; Buus, S; Stryhn, A

    1996-01-01

    the exopeptidase Aminopeptidase N (APN, CD13) as one of the enzymes involved in the observed cell-surface antigen processing. The NH2-terminal end of the longer peptide could, even while bound to major histocompatibility complex (MHC) class II molecules, be digested by APN with dramatic consequences...

  17. Carbon dioxide is tightly bound in the [Co(Pyridine)(CO{sub 2})]{sup −} anionic complex

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Jacob D.; Buytendyk, Allyson M.; Zhang, Xinxing; Bowen, Kit H., E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kim, Seong K. [Department of Chemistry, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-11-14

    The [Co(Pyridine)(CO{sub 2})]{sup −} anionic complex was studied through the combination of photoelectron spectroscopy and density functional theory calculations. This complex was envisioned as a primitive model system for studying CO{sub 2} binding to negatively charged sites in metal organic frameworks. The vertical detachment energy (VDE) measured via the photoelectron spectrum is 2.7 eV. Our calculations imply a structure for [Co(Pyridine)(CO{sub 2})]{sup −} in which a central cobalt atom is bound to pyridine and CO{sub 2} moieties on either sides. This structure was validated by acceptable agreement between the calculated and measured VDE values. Based on our calculations, we found CO{sub 2} to be bound within the anionic complex by 1.4 eV.

  18. The program complexity on Universal Turing Machines, and a proposal to find efficient n-bounded algorithms of NPC problems by machine enumeration

    CERN Document Server

    Zhou, YuQian

    2012-01-01

    This paper proposes a method to find efficient bounded algorithms of NPC problems by machine enumeration. The key contributions are: * On Universal Turing Machines, a program's time complexity should be characterized as: execution time(n) = loading time(n) + running time(n). * Introduces the concept of bounded algorithms; proposes a comparison based criterion to decide if a bounded algorithm is inefficient; and establishes the length upper bound of efficient bounded programs. * Introduces a new way to evaluate program complexity by using the growth rate characteristic function, which is more easily machine checkable based on observations.

  19. Complexity of stochastic branch and bound methods for belief tree search in Bayesian reinforcement learning

    OpenAIRE

    N D

    2009-01-01

    There has been a lot of recent work on Bayesian methods for reinforcement learning exhibiting near-optimal online performance. The main obstacle facing such methods is that in most problems of interest, the optimal solution involves planning in an infinitely large tree. However, it is possible to obtain stochastic lower and upper bounds on the value of each tree node. This enables us to use stochastic branch and bound algorithms to search the tree efficiently. This paper proposes two such alg...

  20. Understanding Carbohydrates

    Science.gov (United States)

    ... Low-calorie sweeteners are also called artificial sweeteners, sugar substitutes or non-nutritive sweeteners. They can be used to sweeten food and drinks for less calories and carbohydrate when they replace sugar. Sugar and Desserts With diabetes, it's important to ...

  1. Healthy carbohydrates

    Science.gov (United States)

    Functional foods include dietary fiber consisting of health-promoting carbohydrates. We have produced novel prebiotics from orange peel and observed that they extend the shelf life of probiotic bacteria in synbiotics. Some pectic-oligosaccharides and xyloglucan-oligosaccharides also have anti-adhesi...

  2. Generation of bound states of pulses in a soliton laser with complex relaxation of a saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Zolotovskii, I O; Korobko, D A; Okhotnikov, O G [Ulyanovsk State University, Ulyanovsk (Russian Federation); Gumenyuk, R V [Optoelectronics Research Center, Tampere University of Technology, Tampere (Finland)

    2015-01-31

    A numerical model of a soliton fibre laser with a semiconductor saturable absorber mirror (SESAM), characterised by the complex dynamics of absorption relaxation, is considered. It is shown that stationary bound states of pulses can be formed in this laser as a result of their interaction via the dispersion-wave field. The stability of stationary bound states of several pulses is analysed. It is shown that an increase in the number of pulses in a stationary bound state leads eventually to its decay and formation of a random bunch. It is found that the bunch stability is caused by the manifestation of nonlinear self-phase modulation, which attracts pulses to the bunch centre. The simulation results are in qualitative agreement with experimental data. (nonlinear optical phenomena)

  3. Tight bounds on the randomized communication complexity of symmetric XOR functions in one-way and SMP models

    CERN Document Server

    Leung, Ming Lam; Zhang, Shengyu

    2011-01-01

    We study the communication complexity of symmetric XOR functions, namely functions $f: \\{0,1\\}^n \\times \\{0,1\\}^n \\rightarrow \\{0,1\\}$ that can be formulated as $f(x,y)=D(|x\\oplus y|)$ for some predicate $D: \\{0,1,...,n\\} \\rightarrow \\{0,1\\}$, where $|x\\oplus y|$ is the Hamming weight of the bitwise XOR of $x$ and $y$. We give a public-coin randomized protocol in the Simultaneous Message Passing (SMP) model, with the communication cost matching the known lower bound for the \\emph{quantum} and \\emph{two-way} model up to a logarithm factor. As a corollary, this closes a quadratic gap between quantum lower bound and randomized upper bound for the one-way model, answering an open question raised in Shi and Zhang \\cite{SZ09}.

  4. Host-Guest Chemistry in the Gas Phase: Complex Formation of Cucurbit[6]uril with Proton-bound Water Dimer

    Science.gov (United States)

    Noh, Dong Hun; Lee, Shin Jung C.; Lee, Jong Wha; Kim, Hugh I.

    2014-03-01

    The hydration of cucurbit[6]uril (CB[6]) in the gas phase is investigated using electrospray ionization traveling wave ion mobility mass spectrometry (ESI-TWIM-MS). Highly abundant dihydrated and tetrahydrated species of diprotonated CB[6] are found in the ESI-TWIM-MS spectrum. The hydration patterns of the CB[6] ion and the dissociation patterns of the hydrated CB[6] ion indicate that two water molecules are bound to each other, forming a water dimer in the CB[6] complex. Ion mobility studies combined with the structures calculated by density functional theory suggest that the proton-bound water dimer is present as a Zundel-like structure in the CB[6] portal, forming a hydrogen bond network with carbonyl groups of the CB[6]. When a large guest molecule is bound to a CB[6] portal, water molecules cannot bind to the portal. In addition, the strong binding energy of the water dimer blocks the portal, hindering the insertion of the long alkyl chain of the guest molecule into the CB[6] cavity. With small alkali metal cations, such as Li+ and Na+, a single water molecule interacts with the CB[6] portal, forming hydrogen bonds with the carbonyl groups of CB[6]. A highly stable Zundel-like structure of the proton-bound water dimer or a metal-bound water molecule at the CB[6] portal is suggested as an initial hydration process for CB[6], which is only dissolved in aqueous solution with acid or alkali metal ions.

  5. Peptide-lanthanide cation equilibria in aqueous phase. I. Bound shifts for L-carnosine-praseodymium complexes

    Science.gov (United States)

    Mossoyan, J.; Asso, M.; Benlian, D.

    L-Carnosine complexes of Pr 3+ were characterized in aqueous solution by 1H NMR and potentiometric titration. A rigorous treatment of chemical shifts and pH variation data with lanthanide concentration is presented. Two different forms of the peptide ligand, forming simultaneously two complexes, were taken into account. At low pH values the cation is only coordinated at the carboxylate site of the ligand in a weak complex ( β2 = 6) whereas in neutral solution a stronger complex ( β1 = 37) is present as a consequence of the deprotonation of the imidazole ring. The computation of induced bound shifts † 2 and Δ1 for resonating nuclei of the peptide in both forms yields consistent figures. These provide the experimental basis for a conformational model which is usually not obtainable for labile complexes with low stability constants.

  6. Ab initio characterization of the Ne-I2 van der Waals complex: Intermolecular potentials and vibrational bound states

    OpenAIRE

    Delgado Tellez, Laura; Valdés, Álvaro; Prosmiti, Rita; Villarreal, Pablo; Delgado Barrio, Gerardo

    2011-01-01

    A theoretical study of the potential energy surface and bound states is performed for the ground state of the NeI2 van der Waals (vdW) complex. The three-dimensional interaction energies are obtained from ab initio coupled-cluster, coupled-cluster single double (triple)/complete basis set, calculations using large basis sets, of quadruple- through quintuple-zeta quality, in conjunction with relativistic effective core potentials for the heavy iodine atoms. For the analytical representation of...

  7. Dietary carbohydrates and endurance exercise.

    Science.gov (United States)

    Evans, W J; Hughes, V A

    1985-05-01

    Antecedent diet can greatly influence both substrate utilization during exercise and exercise performance itself. A number of studies have convincingly demonstrated that short-term (three to seven days) adaptation to a low carbohydrate diet results in greatly reduced liver and muscle glycogen stores. While carbohydrate utilization after such a diet is reduced, the limited glycogen stores can severely limit endurance exercise performance. High carbohydrate diets on the other hand expand carbohydrate stores which can limit performance. However, long-term adaptation to a low carbohydrate diet can greatly alter muscle and whole body energy metabolism to drastically limit the oxidation of limited carbohydrate stores with no adverse effect on performance. Glycogen loading techniques can result in supercompensation of muscle stores. Exercise induced depletion of muscle glycogen is the most important single factor in this phenomenon. Following the exercise a low carbohydrate diet for two to three days after which a high carbohydrate diet is eaten seemingly has the same effect on increasing muscle glycogen stores as simply eating a high carbohydrate diet. The form of the dietary carbohydrate during glycogen loading should be high in complex carbohydrates; however, the type of dietary starch that effects the greatest rate of resynthesis has not been investigated. Rapid resynthesis of glycogen following exercise is at least in part due to increased insulin sensitivity. The enhanced glucose transport caused by the increased sensitivity provides substrate for glycogen synthase. How rapidly this enhanced sensitivity returns to pre-exercise levels in humans is uncertain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3993621

  8. Microbial degradation of whole-grain complex carbohydrates and impact on short-chain fatty acids and health

    DEFF Research Database (Denmark)

    Knudsen, Knud Erik Bach

    2015-01-01

    polyphenolic ether lignin. The highest concentration of NSPs and lignin is found in the outer cell layers of the grain, and refined flour will consequently be depleted of a large proportion of insoluble DF components. The flow and composition of carbohydrates to the large intestine are directly related to the...... intake of DF. The type and composition of cereal DF can consequently be used to modulate the microbial composition and activity as well as the production and molar ratios of short-chain fatty acids (SCFAs). Arabinoxylans and β-glucan in whole-grain cereals and cereal ingredients have been shown to...... augment SCFA production, with the strongest relative effect on butyrate. When arabinoxylans were provided as a concentrate, the effect was only on total SCFA production. Increased SCFA production in the large intestine was shown by the concentration in the portal vein, whereas the impact on the...

  9. Structural insights into calcium-bound S100P and the V domain of the RAGE complex.

    Directory of Open Access Journals (Sweden)

    Srinivasa R Penumutchu

    Full Text Available The S100P protein is a member of the S100 family of calcium-binding proteins and possesses both intracellular and extracellular functions. Extracellular S100P binds to the cell surface receptor for advanced glycation end products (RAGE and activates its downstream signaling cascade to meditate tumor growth, drug resistance and metastasis. Preventing the formation of this S100P-RAGE complex is an effective strategy to treat various disease conditions. Despite its importance, the detailed structural characterization of the S100P-RAGE complex has not yet been reported. In this study, we report that S100P preferentially binds to the V domain of RAGE. Furthermore, we characterized the interactions between the RAGE V domain and Ca(2+-bound S100P using various biophysical techniques, including isothermal titration calorimetry (ITC, fluorescence spectroscopy, multidimensional NMR spectroscopy, functional assays and site-directed mutagenesis. The entropy-driven binding between the V domain of RAGE and Ca(+2-bound S100P was found to lie in the micromolar range (Kd of ∼ 6 µM. NMR data-driven HADDOCK modeling revealed the putative sites that interact to yield a proposed heterotetrameric model of the S100P-RAGE V domain complex. Our study on the spatial structural information of the proposed protein-protein complex has pharmaceutical relevance and will significantly contribute toward drug development for the prevention of RAGE-related multifarious diseases.

  10. Separation of galactoglucomannans, lignin, and lignin-carbohydrate complexes from hot-water-extracted Norway spruce by cross-flow filtration and adsorption chromatography

    Directory of Open Access Journals (Sweden)

    Niklas Westerberg

    2012-11-01

    Full Text Available A simple method to simultaneously recover polymeric carbohydrates, mainly galactoglucomannans (GGM, lignin, and lignin-carbohydrate complex (LCC from hot-water-extracted Norway spruce wood is presented. The isolation method consists of cross-flow filtration, where high and low molecular mass species are removed, followed by fixed-bed adsorption on a hydrophobic polymeric resin (XAD-16 to remove lignins and lignans. In the second step of fixed-bed adsorption, a phenylic reversed-phase analytical chromatography column, where mass transport resistance is minimized and a very high selectivity towards aromatic compounds have been observed, was used to separate LCC from GGM. The isolated LCC fraction contained about 10% aromatics, whereas the upgraded GGM fraction contained about 1.5% aromatics and the lignin fraction contained about 56% aromatics. Polymeric xylan was accumulated in the GGM fraction, while mannose was the dominant sugar found in the LCC fraction. As products, approximately 7% was recovered in the lignin fraction in the first adsorptive step, 5% was recovered as LCC, and 88% as upgraded hemicelluloses.

  11. Iron-sulfur Proteins Are the Major Source of Protein-bound Dinitrosyl Iron Complexes Formed in Escherichia coli Cells under Nitric Oxide Stress

    OpenAIRE

    Landry, Aaron P.; Duan, Xuewu; Huang, Hao; Ding, Huangen

    2011-01-01

    Protein-bound dinitrosyl iron complexes (DNICs) have been observed in prokaryotic and eukaryotic cells under nitric oxide (NO) stress. The identity of proteins that bind DNICs, however, still remains elusive. Here we demonstrate that iron-sulfur proteins are the major source of protein-bound DNICs formed in Escherichia coli cells under NO stress. Expression of recombinant iron-sulfur proteins, but not the proteins without iron-sulfur clusters, almost doubles the amount of protein-bound DNICs ...

  12. Crystal Structure of a CRISPR RNA-guided Surveillance Complex Bound to a ssDNA Target

    Energy Technology Data Exchange (ETDEWEB)

    Mulepati, Sabin [Johns Hopkins Univ., Baltimore, MD (United States); Heroux, Annie; Bailey, Scott [Johns Hopkins Univ., Baltimore, MD (United States)

    2014-09-19

    In prokaryotes, RNA derived from type I and type III CRISPR loci direct large ribonucleoprotein complexes to destroy invading bacteriophage and plasmids. In Escherichia coli, this 405-kilodalton complex is called Cascade. We report the crystal structure of Cascade bound to a single-stranded DNA (ssDNA) target at a resolution of 3.03 angstroms. The structure reveals that the CRISPR RNA and target strands do not form a double helix but instead adopt an underwound ribbon-like structure. This noncanonical structure is facilitated by rotation of every sixth nucleotide out of the RNA-DNA hybrid and is stabilized by the highly interlocked organization of protein subunits. These studies provide insight into both the assembly and the activity of this complex and suggest a mechanism to enforce fidelity of target binding.

  13. Carbohydrates and dietary fiber.

    Science.gov (United States)

    Suter, P M

    2005-01-01

    The most widely spread eating habit is characterized by a reduced intake of dietary fiber, an increased intake of simple sugars, a high intake of refined grain products, an altered fat composition of the diet, and a dietary pattern characterized by a high glycemic load, an increased body weight and reduced physical activity. In this chapter the effects of this eating pattern on disease risk will be outlined. There are no epidemiological studies showing that the increase of glucose, fructose or sucrose intake is directly and independently associated with an increased risk of atherosclerosis or coronary heart disease (CHD). On the other hand a large number of studies has reported a reduction of fatal and non-fatal CHD events as a function of the intake of complex carbohydrates--respectively 'dietary fiber' or selected fiber-rich food (e.g., whole grain cereals). It seems that eating too much 'fast' carbohydrate [i.e., carbohydrates with a high glycemic index (GI)] may have deleterious long-term consequences. Indeed the last decades have shown that a low fat (and consecutively high carbohydrate) diet alone is not the best strategy to combat modern diseases including atherosclerosis. Quantity and quality issues in carbohydrate nutrient content are as important as they are for fat. Multiple lines of evidence suggest that for cardiovascular disease prevention a high sugar intake should be avoided. There is growing evidence of the high impact of dietary fiber and foods with a low GI on single risk factors (e.g., lipid pattern, diabetes, inflammation, endothelial function etc.) as well as also the development of the endpoints of atherosclerosis especially CHD. PMID:16596802

  14. Structural characterisation of human galectin-4 N-terminal carbohydrate recognition domain in complex with glycerol, lactose, 3'-sulfo-lactose, and 2'-fucosyllactose.

    Science.gov (United States)

    Bum-Erdene, Khuchtumur; Leffler, Hakon; Nilsson, Ulf J; Blanchard, Helen

    2016-01-01

    Galectin-4 is a tandem-repeat galectin with two distinct carbohydrate recognition domains (CRD). Galectin-4 is expressed mainly in the alimentary tract and is proposed to function as a lipid raft and adherens junction stabilizer by its glycan cross-linking capacity. Galectin-4 plays divergent roles in cancer and inflammatory conditions, either promoting or inhibiting each disease progression, depending on the specific pathological condition. The study of galectin-4's ligand-binding profile may help decipher its roles under specific conditions. Here we present the X-ray structures of human galectin-4 N-terminal CRD (galectin-4N) bound to different saccharide ligands. Galectin-4's overall fold and its core interactions to lactose are similar to other galectin CRDs. Galectin-4N recognises the sulfate cap of 3'-sulfated glycans by a weak interaction through Arg45 and two water-mediated hydrogen bonds via Trp84 and Asn49. When galectin-4N interacts with the H-antigen mimic, 2'-fucosyllactose, an interaction is formed between the ring oxygen of fucose and Arg45. The extended binding site of galectin-4N may not be well suited to the A/B-antigen determinants, α-GalNAc/α-Gal, specifically due to clashes with residue Phe47. Overall, galectin-4N favours sulfated glycans whilst galectin-4C prefers blood group determinants. However, the two CRDs of galectin-4 can, to a less extent, recognise each other's ligands. PMID:26828567

  15. Peptide specific expansion of CD8(+) T cells by recombinant plate bound MHC/peptide complexes

    DEFF Research Database (Denmark)

    Schmidt, Esben G W; Buus, Soren; Thorn, Mette;

    2009-01-01

    in vitro T cell stimulation was investigated. By use of an antigenic peptide derived from the cytomegalovirus (CMVp) we tested the stimulatory efficacy of recombinant plate bound MHC molecules (PB-MHC), being immobilized in culture plates. A single stimulation of non-adherent peripheral blood...... effect of new stimulatory cocktails, e.g. cytokines and co-stimulatory molecules, by use of the present rapid and easy-to-use method of expanding peptide specific T cells.......Development of methods for efficient in vitro stimulation and expansion of peptide specific CD8(+) T cells is compelling not only with respect to adoptive T cell therapy but also regarding analysis of T cell responses and search for new immunogenic peptides. In the present study, a new approach to...

  16. Theoretical investigation of potential energy surface and bound states for the van der Waals complex Ar–BrCl dimer

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Rui [School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou (China); Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Li, Song, E-mail: lsong@yangtzeu.edu.cn [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Chen, Shan-Jun; Chen, Yan [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Zheng, Li-Min [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China)

    2015-09-08

    Highlights: • A two-dimensional potential for Ar–BrCl is constructed at the CCSD(T) level. • The PES is characterized by three minima and two saddle points between them. • Bound state calculations were carried out for the complex. - Abstract: The intermolecular potential energy surface (PES) of the ground electronic state for the Ar–BrCl dimer is constructed at the CCSD(T) level with the aug-cc-pVQZ basis set and mid-bond functions. The PES is characterized by three minima and two saddle points. The global minimum corresponding to a collinear Ar–BrCl configuration, which has been observed experimentally, is located at R = 4.10 Å and θ = 2.5° with a well depth of −285.207 cm{sup −1}. A nearly T-shaped structure and an anti-linear Ar–ClBr geometry is also predicted. The bound state calculations are preformed to study intermolecular vibrational modes, rotational levels and average structures for the complex. Our transition frequencies, spectroscopic constants and average structures for all isotopomers of the collinear isomer agree well with experimental data. We have also provided pure rotational transitional frequencies for both nearly T-shaped and anti-linear isomers. These results are significant for further experimental investigations of the Ar–BrCl dimer.

  17. Complete genome sequence of the complex carbohydrate-degrading marine bacterium, Saccharophagus degradans strain 2-40 T.

    OpenAIRE

    Weiner, Ronald M.; Taylor, Larry E.; Bernard Henrissat; Loren Hauser; Miriam Land; Coutinho, Pedro M; Corinne Rancurel; Saunders, Elizabeth H.; Atkinson G Longmire; Haitao Zhang; Bayer, Edward A.; Gilbert, Harry J.; Frank Larimer; Zhulin, Igor B.; Ekborg, Nathan A.

    2008-01-01

    The marine bacterium Saccharophagus degradans strain 2-40 (Sde 2-40) is emerging as a vanguard of a recently discovered group of marine and estuarine bacteria that recycles complex polysaccharides. We report its complete genome sequence, analysis of which identifies an unusually large number of enzymes that degrade >10 complex polysaccharides. Not only is this an extraordinary range of catabolic capability, many of the enzymes exhibit unusual architecture including novel combinations of catal...

  18. Interaction of natural complexing agents with soil bound heavy metals -geochemical and environmental technical aspects

    International Nuclear Information System (INIS)

    The sanitation of heavy metal polluted soils requires the application of an adequate technology, which should be consistent in its ecological aims and methodology. Therefore a research programme has been developed at the 'Institute of Ecological Chemistry' of the 'GSF-Research Center', Neuherberg, which has its starting point in the study of influences of natural organic complexing agents on the chemical activity and dynamic of heavy metals in soils. The groundlaying idea is to elevate the concentration of complexing agents in the soil solution by additional application and possible stimulation of their microbial production to such an extent, that heavy metals will be enhanced solubilized, mobilized and removed together with the seepage water. Batch experiments in order to extract heavy metals from typical soil components (bentonite, peat) by amino acids demonstrate, that removal rates up to 95% can be obtained. (orig.)

  19. A Polycomb complex remains bound through DNA replication in the absence of other eukaryotic proteins

    KAUST Repository

    Lengsfeld, Bettina M.

    2012-09-17

    Propagation of chromatin states through DNA replication is central to epigenetic regulation and can involve recruitment of chromatin proteins to replicating chromatin through interactions with replication fork components. Here we show using a fully reconstituted T7 bacteriophage system that eukaryotic proteins are not required to tether the Polycomb complex PRC1 to templates during DNA replication. Instead, DNA binding by PRC1 can withstand passage of a simple replication fork.

  20. Structure of promoter-bound TFIID and model of human pre-initiation complex assembly.

    Science.gov (United States)

    Louder, Robert K; He, Yuan; López-Blanco, José Ramón; Fang, Jie; Chacón, Pablo; Nogales, Eva

    2016-03-31

    The general transcription factor IID (TFIID) plays a central role in the initiation of RNA polymerase II (Pol II)-dependent transcription by nucleating pre-initiation complex (PIC) assembly at the core promoter. TFIID comprises the TATA-binding protein (TBP) and 13 TBP-associated factors (TAF1-13), which specifically interact with a variety of core promoter DNA sequences. Here we present the structure of human TFIID in complex with TFIIA and core promoter DNA, determined by single-particle cryo-electron microscopy at sub-nanometre resolution. All core promoter elements are contacted by subunits of TFIID, with TAF1 and TAF2 mediating major interactions with the downstream promoter. TFIIA bridges the TBP-TATA complex with lobe B of TFIID. We also present the cryo-electron microscopy reconstruction of a fully assembled human TAF-less PIC. Superposition of common elements between the two structures provides novel insights into the general role of TFIID in promoter recognition, PIC assembly, and transcription initiation. PMID:27007846

  1. Catalytic Conversion of Carbohydrates

    DEFF Research Database (Denmark)

    Osmundsen, Christian Mårup

    a renewable route to aromatics. The conversion of biomass by high temperature processes is a desirable prospect due to the high volumetric production rates which can be achieved, and the ability of these types of processes to convert a wide range of substrates. Current processes however typically...... process could prove to be an efficient initial conversion step in the utilization of biomass for chemicals production. The shift from an oil based chemical industry to one based on renewable resources is bound to happen sooner or later, however the environmental problems associated with the burning of...... production of commodity chemicals from the most abundantly available renewable source of carbon, carbohydrates. The production of alkyl lactates by the Lewis acid catalyzed conversion of hexoses is an interesting alternative to current fermentation based processes. A range of stannosilicates were...

  2. Complete genome sequence of the complex carbohydrate-degrading marine bacterium, Saccharophagus degradans strain 2-40 T.

    Directory of Open Access Journals (Sweden)

    Ronald M Weiner

    2008-05-01

    Full Text Available The marine bacterium Saccharophagus degradans strain 2-40 (Sde 2-40 is emerging as a vanguard of a recently discovered group of marine and estuarine bacteria that recycles complex polysaccharides. We report its complete genome sequence, analysis of which identifies an unusually large number of enzymes that degrade >10 complex polysaccharides. Not only is this an extraordinary range of catabolic capability, many of the enzymes exhibit unusual architecture including novel combinations of catalytic and substrate-binding modules. We hypothesize that many of these features are adaptations that facilitate depolymerization of complex polysaccharides in the marine environment. This is the first sequenced genome of a marine bacterium that can degrade plant cell walls, an important component of the carbon cycle that is not well-characterized in the marine environment.

  3. [Carbohydrates and fiber].

    Science.gov (United States)

    Lajolo, F M; de Menezes, E W; Filisetti-Cozzi, T M

    1988-09-01

    Dietary carbohydrates comprise two fractions that may be classified as digestible, and which are useful as energy sources (simple and complex carbohydrates) and fiber, which is presumed to be of no use to the human body. There are insufficient epidemiologic data on the metabolic effects of simple carbohydrates and it is not advisable to make quantitative recommendations of intake. It is questionable to recommend in developing countries that a fixed proportion of dietary energy be derived from simple sugars, due to the high prevalence of deficient energy intake, cultural habits, and regional differences in food intake and physical activity. In relation to recommendations of complex carbohydrates, it should be considered that their absorption is influenced by many factors inherent to the individual and to the foods. Fiber is defined as a series of different substances derived from tissue structures, cellular residues and undigested chemical substances that may be partially utilized after intestinal bacteria have acted on them. There is not a clear definition of the chemical composition of fiber, but it consists mainly of polysaccharides (such as cellulose, hemicellulose and pectins), lignin and end products of the interactions of various food components. The effects of fiber, such as control of food intake, regulation of gastrointestinal transit, post-prandial blood concentrations of cholesterol, glucose and insulin, flatulence and alterations in nutrient bioavailability are due to various physical properties inherent to its chemical components. Impairment of nutrient absorption may be harmful, mainly among populations whose food intake is lower than their energy needs, and with a high fiber content. This may be particularly important in pregnant women, growing children and the elderly, and should be considered when making nutrient recommendations. A precise knowledge of fiber is also important to calculate the real energy value of foods, mainly for two reasons: 1

  4. Structure of the complex of Neisseria gonorrhoeae N-acetyl-L-glutamate synthase with a bound bisubstrate analog.

    Science.gov (United States)

    Zhao, Gengxiang; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2013-01-25

    N-Acetyl-L-glutamate synthase catalyzes the conversion of AcCoA and glutamate to CoA and N-acetyl-L-glutamate (NAG), the first step of the arginine biosynthetic pathway in lower organisms. In mammals, NAG is an obligate cofactor of carbamoyl phosphate synthetase I in the urea cycle. We have previously reported the structures of NAGS from Neisseria gonorrhoeae (ngNAGS) with various substrates bound. Here we reported the preparation of the bisubstrate analog, CoA-S-acetyl-L-glutamate, the crystal structure of ngNAGS with CoA-NAG bound, and kinetic studies of several active site mutants. The results are consistent with a one-step nucleophilic addition-elimination mechanism with Glu353 as the catalytic base and Ser392 as the catalytic acid. The structure of the ngNAGS-bisubstrate complex together with the previous ngNAGS structures delineates the catalytic reaction path for ngNAGS. PMID:23261468

  5. Microbial Degradation of Whole-Grain Complex Carbohydrates and Impact on Short-Chain Fatty Acids and Health1234

    OpenAIRE

    Bach Knudsen, Knud Erik

    2015-01-01

    Whole-grain cereals have a complex dietary fiber (DF) composition consisting of oligosaccharides (mostly fructans), resistant starch, and nonstarch polysaccharides (NSPs); the most important are arabinoxylans, mixed-linkage β(1,3; 1,4)-d-glucan (β-glucan), and cellulose and the noncarbohydrate polyphenolic ether lignin. The highest concentration of NSPs and lignin is found in the outer cell layers of the grain, and refined flour will consequently be depleted of a large proportion of insoluble...

  6. DNA Sequence Determinants Controlling Affinity, Stability and Shape of DNA Complexes Bound by the Nucleoid Protein Fis.

    Science.gov (United States)

    Hancock, Stephen P; Stella, Stefano; Cascio, Duilio; Johnson, Reid C

    2016-01-01

    The abundant Fis nucleoid protein selectively binds poorly related DNA sequences with high affinities to regulate diverse DNA reactions. Fis binds DNA primarily through DNA backbone contacts and selects target sites by reading conformational properties of DNA sequences, most prominently intrinsic minor groove widths. High-affinity binding requires Fis-stabilized DNA conformational changes that vary depending on DNA sequence. In order to better understand the molecular basis for high affinity site recognition, we analyzed the effects of DNA sequence within and flanking the core Fis binding site on binding affinity and DNA structure. X-ray crystal structures of Fis-DNA complexes containing variable sequences in the noncontacted center of the binding site or variations within the major groove interfaces show that the DNA can adapt to the Fis dimer surface asymmetrically. We show that the presence and position of pyrimidine-purine base steps within the major groove interfaces affect both local DNA bending and minor groove compression to modulate affinities and lifetimes of Fis-DNA complexes. Sequences flanking the core binding site also modulate complex affinities, lifetimes, and the degree of local and global Fis-induced DNA bending. In particular, a G immediately upstream of the 15 bp core sequence inhibits binding and bending, and A-tracts within the flanking base pairs increase both complex lifetimes and global DNA curvatures. Taken together, our observations support a revised DNA motif specifying high-affinity Fis binding and highlight the range of conformations that Fis-bound DNA can adopt. The affinities and DNA conformations of individual Fis-DNA complexes are likely to be tailored to their context-specific biological functions. PMID:26959646

  7. Towards building artificial light harvesting complexes: enhanced singlet-singlet energy transfer between donor and acceptor pairs bound to albumins.

    Science.gov (United States)

    Kumar, Challa V; Duff, Michael R

    2008-12-01

    Specific donor and acceptor pairs have been assembled in bovine serum albumin (BSA), at neutral pH and room temperature, and these dye-protein complexes indicated efficient donor to acceptor singlet-singlet energy transfer. For example, pyrene-1-butyric acid served as the donor and Coumarin 540A served as the acceptor. Both the donor and the acceptor bind to BSA with affinity constants in excess of 2x10(5) M(-1), as measured in absorption and circular dichroism (CD) spectral titrations. Simultaneous binding of both the donor and the acceptor chromophores was supported by CD spectra and one chromophore did not displace the other from the protein host, even when limited concentrations of the host were used. For example, a 1:1:1 complex between the donor, acceptor and the host can be readily formed, and spectral data clearly show that the binding sites are mutually exclusive. The ternary complexes (two different ligands bound to the same protein molecule) provided opportunities to examine singlet-singlet energy transfer between the protein-bound chromophores. Donor emission was quenched by the addition of the acceptor, in the presence of limited amounts of BSA, while no energy transfer was observed in the absence of the protein host, under the same conditions. The excitation spectra of the donor-acceptor-host complexes clearly show the sensitization of acceptor emission by the donor. Protein denaturation, as induced by the addition of urea or increasing the temperature to 360 K, inhibited energy transfer, which indicate that protein structure plays an important role. Sensitization also proceeded at low temperature (77 K) and diffusion of the donor or the acceptor is not required for energy transfer. Stern-Volmer quenching plots show that the quenching constant is (3.1+/-0.2)x10(4) M(-1), at low acceptor concentrations (hosts for the above experiments. For the first time, non-natural systems have been self-assembled which can capture donor-acceptor pairs and facilitate

  8. Carbohydrate clearance receptors in transfusion medicine

    DEFF Research Database (Denmark)

    Sørensen, Anne Louise Tølbøll; Clausen, Henrik; Wandall, Hans H

    2012-01-01

    Complex carbohydrates play important functions for circulation of proteins and cells. They provide protective shields and refraction from non-specific interactions with negative charges from sialic acids to enhance circulatory half-life. For recombinant protein therapeutics carbohydrates are espe...

  9. Chirality of weakly bound complexes: The potential energy surfaces for the hydrogen-peroxide−noble-gas interactions

    Energy Technology Data Exchange (ETDEWEB)

    Roncaratti, L. F., E-mail: lz@fis.unb.br; Leal, L. A.; Silva, G. M. de [Instituto de Física, Universidade de Brasília, 70910 Brasília (Brazil); Pirani, F. [Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, V. [Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Instituto de Física, Universidade Federal da Bahia, 40210 Salvador (Brazil); Gargano, R. [Instituto de Física, Universidade de Brasília, 70910 Brasília (Brazil); Departments of Chemistry and Physics, University of Florida, Quantum Theory Project, Gainesville, Florida 32611 (United States)

    2014-10-07

    We consider the analytical representation of the potential energy surfaces of relevance for the intermolecular dynamics of weakly bound complexes of chiral molecules. In this paper we study the H{sub 2}O{sub 2}−Ng (Ng=He, Ne, Ar, Kr, and Xe) systems providing the radial and the angular dependence of the potential energy surface on the relative position of the Ng atom. We accomplish this by introducing an analytical representation which is able to fit the ab initio energies of these complexes in a wide range of geometries. Our analysis sheds light on the role that the enantiomeric forms and the symmetry of the H{sub 2}O{sub 2} molecule play on the resulting barriers and equilibrium geometries. The proposed theoretical framework is useful to study the dynamics of the H{sub 2}O{sub 2} molecule, or other systems involving O–O and S–S bonds, interacting by non-covalent forces with atoms or molecules and to understand how the relative orientation of the O–H bonds changes along collisional events that may lead to a hydrogen bond formation or even to selectivity in chemical reactions.

  10. Cryo-EM of Mitotic Checkpoint Complex-Bound APC/C Reveals Reciprocal and Conformational Regulation of Ubiquitin Ligation.

    Science.gov (United States)

    Yamaguchi, Masaya; VanderLinden, Ryan; Weissmann, Florian; Qiao, Renping; Dube, Prakash; Brown, Nicholas G; Haselbach, David; Zhang, Wei; Sidhu, Sachdev S; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

    2016-08-18

    The mitotic checkpoint complex (MCC) coordinates proper chromosome biorientation on the spindle with ubiquitination activities of CDC20-activated anaphase-promoting complex/cyclosome (APC/C(CDC20)). APC/C(CDC20) and two E2s, UBE2C and UBE2S, catalyze ubiquitination through distinct architectures for linking ubiquitin (UB) to substrates and elongating polyUB chains, respectively. MCC, which contains a second molecule of CDC20, blocks APC/C(CDC20)-UBE2C-dependent ubiquitination of Securin and Cyclins, while differentially determining or inhibiting CDC20 ubiquitination to regulate spindle surveillance, checkpoint activation, and checkpoint termination. Here electron microscopy reveals conformational variation of APC/C(CDC20)-MCC underlying this multifaceted regulation. MCC binds APC/C-bound CDC20 to inhibit substrate access. However, rotation about the CDC20-MCC assembly and conformational variability of APC/C modulate UBE2C-catalyzed ubiquitination of MCC's CDC20 molecule. Access of UBE2C is limiting for subsequent polyubiquitination by UBE2S. We propose that conformational dynamics of APC/C(CDC20)-MCC modulate E2 activation and determine distinctive ubiquitination activities as part of a response mechanism ensuring accurate sister chromatid segregation. PMID:27522463

  11. Crystal structure of product-bound complex of UDP-N-acetyl-D-mannosamine dehydrogenase from Pyrococcus horikoshii OT3

    Energy Technology Data Exchange (ETDEWEB)

    Pampa, K.J., E-mail: sagarikakj@gmail.com [Department of Studies in Microbiology, University of Mysore, Mysore 570 006 (India); Lokanath, N.K. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Girish, T.U. [Department of General Surgery, JSS Medical College and Hospital, JSS University, Mysore 570 015 (India); Kunishima, N. [Advanced Protein Crystallography Research Group, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148 (Japan); Rai, V.R. [Department of Studies in Microbiology, University of Mysore, Mysore 570 006 (India)

    2014-10-24

    Highlights: • Determined the structure of UDP-D-ManNAcADH to a resolution of 1.55 Å. • First complex structure of PhUDP-D-ManNAcADH with UDP-D-ManMAcA. • The monomeric structure consists of three distinct domains. • Cys258 acting as catalytic nucleophilic and Lys204 acts as acid/base catalyst. • Oligomeric state plays an important role for the catalytic function. - Abstract: UDP-N-acetyl-D-mannosamine dehydrogenase (UDP-D-ManNAcDH) belongs to UDP-glucose/GDP-mannose dehydrogenase family and catalyzes Uridine-diphospho-N-acetyl-D-mannosamine (UDP-D-ManNAc) to Uridine-diphospho-N-acetyl-D-mannosaminuronic acid (UDP-D-ManNAcA) through twofold oxidation of NAD{sup +}. In order to reveal the structural features of the Pyrococcus horikoshii UDP-D-ManNAcADH, we have determined the crystal structure of the product-bound enzyme by X-ray diffraction to resolution of 1.55 Å. The protomer folds into three distinct domains; nucleotide binding domain (NBD), substrate binding domain (SBD) and oligomerization domain (OD, involved in the dimerization). The clear electron density of the UDP-D-ManNAcA is observed and the residues binding are identified for the first time. Crystal structures reveal a tight dimeric polymer chains with product-bound in all the structures. The catalytic residues Cys258 and Lys204 are conserved. The Cys258 acts as catalytic nucleophile and Lys204 as acid/base catalyst. The product is directly interacts with residues Arg211, Thr249, Arg244, Gly255, Arg289, Lys319 and Arg398. In addition, the structural parameters responsible for thermostability and oligomerization of the three dimensional structure are analyzed.

  12. Effect of pullulan nanoparticle surface charges on HSA complexation and drug release behavior of HSA-bound nanoparticles.

    Directory of Open Access Journals (Sweden)

    Xiaojun Tao

    Full Text Available Nanoparticle (NP compositions such as hydrophobicity and surface charge are vital to determine the presence and amount of human serum albumin (HSA binding. The HSA binding influences drug release, biocompatibility, biodistribution, and intercellular trafficking of nanoparticles (NPs. Here, we prepared 2 kinds of nanomaterials to investigate HSA binding and evaluated drug release of HSA-bound NPs. Polysaccharides (pullulan carboxyethylated to provide ionic derivatives were then conjugated to cholesterol groups to obtain cholesterol-modified carboxyethyl pullulan (CHCP. Cholesterol-modified pullulan (CHP conjugate was synthesized with a similar degree of substitution of cholesterol moiety to CHCP. CHCP formed self-aggregated NPs in aqueous solution with a spherical structure and zeta potential of -19.9 ± 0.23 mV, in contrast to -1.21 ± 0.12 mV of CHP NPs. NPs could quench albumin fluorescence intensity with maximum emission intensity gradually decreasing up to a plateau at 9 to 12 h. Binding constants were 1.12 × 10(5 M(-1 and 0.70 × 10(5 M(-1 to CHP and CHCP, respectively, as determined by Stern-Volmer analysis. The complexation between HSA and NPs was a gradual process driven by hydrophobic force and inhibited by NP surface charge and shell-core structure. HSA conformation was altered by NPs with reduction of α-helical content, depending on interaction time and particle surface charges. These NPs could represent a sustained release carrier for mitoxantrone in vitro, and the bound HSA assisted in enhancing sustained drug release.

  13. Strategies for improved modeling of GPCR-drug complexes: blind predictions of serotonin receptors bound to ergotamine.

    Science.gov (United States)

    Rodríguez, David; Ranganathan, Anirudh; Carlsson, Jens

    2014-07-28

    The recent increase in the number of atomic-resolution structures of G protein-coupled receptors (GPCRs) has contributed to a deeper understanding of ligand binding to several important drug targets. However, reliable modeling of GPCR-ligand complexes for the vast majority of receptors with unknown structure remains to be one of the most challenging goals for computer-aided drug design. The GPCR Dock 2013 assessment, in which researchers were challenged to predict the crystallographic structures of serotonin 5-HT(1B) and 5-HT(2B) receptors bound to ergotamine, provided an excellent opportunity to benchmark the current state of this field. Our contributions to GPCR Dock 2013 accurately predicted the binding mode of ergotamine with RMSDs below 1.8 Å for both receptors, which included the best submissions for the 5-HT(1B) complex. Our models also had the most accurate description of the binding sites and receptor-ligand contacts. These results were obtained using a ligand-guided homology modeling approach, which combines extensive molecular docking screening with incorporation of information from multiple crystal structures and experimentally derived restraints. In this work, we retrospectively analyzed thousands of structures that were generated during the assessment to evaluate our modeling strategies. Major contributors to accuracy were found to be improved modeling of extracellular loop two in combination with the use of molecular docking to optimize the binding site for ligand recognition. Our results suggest that modeling of GPCR-drug complexes has reached a level of accuracy at which structure-based drug design could be applied to a large number of pharmaceutically relevant targets. PMID:25030302

  14. Functions that Protect Escherichia coli from Tightly Bound DNA-Protein Complexes Created by Mutant EcoRII Methyltransferase.

    Science.gov (United States)

    Henderson, Morgan L; Kreuzer, Kenneth N

    2015-01-01

    Expression of mutant EcoRII methyltransferase protein (M.EcoRII-C186A) in Escherichia coli leads to tightly bound DNA-protein complexes (TBCs), located sporadically on the chromosome rather than in tandem arrays. The mechanisms behind the lethality induced by such sporadic TBCs are not well studied, nor is it clear whether very tight binding but non-covalent complexes are processed in the same way as covalent DNA-protein crosslinks (DPCs). Using 2D gel electrophoresis, we found that TBCs induced by M.EcoRII-C186A block replication forks in vivo. Specific bubble molecules were detected as spots on the 2D gel, only when M.EcoRII-C186A was induced, and a mutation that eliminates a specific EcoRII methylation site led to disappearance of the corresponding spot. We also performed a candidate gene screen for mutants that are hypersensitive to TBCs induced by M.EcoRII-C186A. We found several gene products necessary for protection against these TBCs that are known to also protect against DPCs induced with wild-type M.EcoRII (after 5-azacytidine incorporation): RecA, RecBC, RecG, RuvABC, UvrD, FtsK, XerCD and SsrA (tmRNA). In contrast, the RecFOR pathway and Rep helicase are needed for protection against TBCs but not DPCs induced by M.EcoRII. We propose that stalled fork processing by RecFOR and RecA promotes release of tightly bound (but non-covalent) blocking proteins, perhaps by licensing Rep helicase-driven dissociation of the blocking M.EcoRII-C186A. Our studies also argued against the involvement of several proteins that might be expected to protect against TBCs. We took the opportunity to directly compare the sensitivity of all tested mutants to two quinolone antibiotics, which target bacterial type II topoisomerases and induce a unique form of DPC. We uncovered rep, ftsK and xerCD as novel quinolone hypersensitive mutants, and also obtained evidence against the involvement of a number of functions that might be expected to protect against quinolones. PMID:25993347

  15. Functions that Protect Escherichia coli from Tightly Bound DNA-Protein Complexes Created by Mutant EcoRII Methyltransferase.

    Directory of Open Access Journals (Sweden)

    Morgan L Henderson

    Full Text Available Expression of mutant EcoRII methyltransferase protein (M.EcoRII-C186A in Escherichia coli leads to tightly bound DNA-protein complexes (TBCs, located sporadically on the chromosome rather than in tandem arrays. The mechanisms behind the lethality induced by such sporadic TBCs are not well studied, nor is it clear whether very tight binding but non-covalent complexes are processed in the same way as covalent DNA-protein crosslinks (DPCs. Using 2D gel electrophoresis, we found that TBCs induced by M.EcoRII-C186A block replication forks in vivo. Specific bubble molecules were detected as spots on the 2D gel, only when M.EcoRII-C186A was induced, and a mutation that eliminates a specific EcoRII methylation site led to disappearance of the corresponding spot. We also performed a candidate gene screen for mutants that are hypersensitive to TBCs induced by M.EcoRII-C186A. We found several gene products necessary for protection against these TBCs that are known to also protect against DPCs induced with wild-type M.EcoRII (after 5-azacytidine incorporation: RecA, RecBC, RecG, RuvABC, UvrD, FtsK, XerCD and SsrA (tmRNA. In contrast, the RecFOR pathway and Rep helicase are needed for protection against TBCs but not DPCs induced by M.EcoRII. We propose that stalled fork processing by RecFOR and RecA promotes release of tightly bound (but non-covalent blocking proteins, perhaps by licensing Rep helicase-driven dissociation of the blocking M.EcoRII-C186A. Our studies also argued against the involvement of several proteins that might be expected to protect against TBCs. We took the opportunity to directly compare the sensitivity of all tested mutants to two quinolone antibiotics, which target bacterial type II topoisomerases and induce a unique form of DPC. We uncovered rep, ftsK and xerCD as novel quinolone hypersensitive mutants, and also obtained evidence against the involvement of a number of functions that might be expected to protect against quinolones.

  16. Carbohydrate Metabolism Disorders

    Science.gov (United States)

    ... in your body tissues. If you have a metabolic disorder, something goes wrong with this process. Carbohydrate metabolism disorders are a group of metabolic disorders. Normally your enzymes break carbohydrates down into glucose ( ...

  17. A strategy for co-translational folding studies of ribosome-bound nascent chain complexes using NMR spectroscopy.

    Science.gov (United States)

    Cassaignau, Anaïs M E; Launay, Hélène M M; Karyadi, Maria-Evangelia; Wang, Xiaolin; Waudby, Christopher A; Deckert, Annika; Robertson, Amy L; Christodoulou, John; Cabrita, Lisa D

    2016-08-01

    During biosynthesis on the ribosome, an elongating nascent polypeptide chain can begin to fold, in a process that is central to all living systems. Detailed structural studies of co-translational protein folding are now beginning to emerge; such studies were previously limited, at least in part, by the inherently dynamic nature of emerging nascent chains, which precluded most structural techniques. NMR spectroscopy is able to provide atomic-resolution information for ribosome-nascent chain complexes (RNCs), but it requires large quantities (≥10 mg) of homogeneous, isotopically labeled RNCs. Further challenges include limited sample working concentration and stability of the RNC sample (which contribute to weak NMR signals) and resonance broadening caused by attachment to the large (2.4-MDa) ribosomal complex. Here, we present a strategy to generate isotopically labeled RNCs in Escherichia coli that are suitable for NMR studies. Uniform translational arrest of the nascent chains is achieved using a stalling motif, and isotopically labeled RNCs are produced at high yield using high-cell-density E. coli growth conditions. Homogeneous RNCs are isolated by combining metal affinity chromatography (to isolate ribosome-bound species) with sucrose density centrifugation (to recover intact 70S monosomes). Sensitivity-optimized NMR spectroscopy is then applied to the RNCs, combined with a suite of parallel NMR and biochemical analyses to cross-validate their integrity, including RNC-optimized NMR diffusion measurements to report on ribosome attachment in situ. Comparative NMR studies of RNCs with the analogous isolated proteins permit a high-resolution description of the structure and dynamics of a nascent chain during its progressive biosynthesis on the ribosome. PMID:27466710

  18. Structural complexes of the agonist, inverse agonist and antagonist bound C5a receptor: insights into pharmacology and signaling.

    Science.gov (United States)

    Rana, Soumendra; Sahoo, Amita Rani; Majhi, Bharat Kumar

    2016-04-26

    The C5a receptor (C5aR) is a pharmacologically important G-protein coupled receptor (GPCR) that interacts with (h)C5a, by recruiting both the "orthosteric" sites (site1 at the N-terminus and site2 at the ECS, extra cellular surface) on C5aR in a two site-binding model. However, the complex pharmacological landscape and the distinguishing chemistry operating either at the "orthosteric" site1 or at the functionally important "orthosteric" site2 of C5aR are still not clear, which greatly limits the understanding of C5aR pharmacology. One of the major bottlenecks is the lack of an experimental structure or a refined model structure of C5aR with appropriately defined active sites. The study attempts to understand the pharmacology at the "orthosteric" site2 of C5aR rationally by generating a highly refined full-blown model structure of C5aR through advanced molecular modeling techniques, and further subjecting it to automated docking and molecular dynamics (MD) studies in the POPC bilayer. The first series of structural complexes of C5aR respectively bound to a linear native peptide agonist ((h)C5a-CT), a small molecule inverse agonist (NDT) and a cyclic peptide antagonist (PMX53) are reported, apparently establishing the unique pharmacological landscape of the "orthosteric" site2, which also illustrates an energetically distinct but coherent competitive chemistry ("cation-π" vs. "π-π" interactions) involved in distinguishing the established ligands known for targeting the "orthosteric" site2 of C5aR. Over a total of 1 μs molecular dynamics (MD) simulation in the POPC bilayer, it is evidenced that while the agonist prefers a "cation-π" interaction, the inverse agonist prefers a "cogwheel/L-shaped" interaction in contrast to the "edge-to-face/T-shaped" type π-π interactions demonstrated by the antagonist by engaging the F275(7.28) of the C5aR. In the absence of a NMR or crystallographically guided model structure of C5aR, the computational model complexes not only

  19. Benchmark calculations with correlated molecular wave functions. IX. The weakly bound complexes Ar - H2 and Ar - HCl

    International Nuclear Information System (INIS)

    The interaction of Ar with H2 and HCl has been studied using Moeller - Plesset perturbation theory (MP2, MP3, MP4) and coupled-cluster [CCSD, CCSD(T)] methods with augmented correlation consistent basis sets. Basis sets as large as triply augmented quadruple zeta quality were used to investigate the convergence trends. Interaction energies were determined using the supermolecule approach with the counterpoise correction to account for basis set superposition error. Comparison with the available empirical potentials finds excellent agreement for both binding energies and transition state. For Ar - H2, the estimated complete basis set (CBS) limits for the binding energies of the two equivalent minima and the connecting transition state (TS) are, respectively, 55 and 47cm-1 at the MP4 level and 54 and 46cm-1 at the CCSD(T) level, respectively [the XC(fit) empirical potential of Bissonnette et al. [J. Chem. Phys. 105, 2639 (1996)] yields 56.6 and 47.8cm-1 for H2 (v=0)]. The estimated CBS limits for the binding energies of the two minima and transition state of Ar - HCl are 185, 155, and 109cm-1 at the MP4 level and 176, 147, and 105cm-1 at the CCSD(T) level, respectively [the H6(4,3,0) empirical potential of Hutson [J. Phys. Chem. 96, 4237 (1992)] yields 176.0, 148.3, and 103.3cm-1 for HCl (v=0)]. Basis sets containing diffuse functions of (dfg) symmetries were found to be essential for accurately modeling these two complexes, which are largely bound by dispersion and induction forces. Highly correlated wave functions were also required for accurate results. This was found to be particularly true for ArHCl, where significant differences in calculated binding energies were observed between MP2, MP4, and CCSD(T). copyright 1998 American Institute of Physics

  20. Workshop to establish databases of carbohydrate spectra

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The workshop was organized to formulate guidelines for establishing spectral databases of complex carbohydrates. The databases will enable the scientific community to avoid the great waste of research effort and funds that frequently occurs when carbohydrate chemists are forced to duplicate the structural characterization of previously characterized complex carbohydrates. Chemists waste their effort on repetitive characterizations because in the absence of spectral databases they are unaware they are analyzing a known molecule until they have completely determined its structure. Chemists will be able to avoid much of this wasted effort when the collections of mass and of nuclear magnetic resonance (NMR) spectra initiated at the workshop are subsequently developed into searchable databases. Then scientists only need query the databases with the spectrum or with information defining the spectrum of an unidentified carbohydrate to find out if it has been previously characterized.

  1. A comparison of ab initio quantum-mechanical and experimental D0 binding energies of eleven H-bonded and eleven dispersion-bound complexes.

    Science.gov (United States)

    Haldar, Susanta; Gnanasekaran, Ramachandran; Hobza, Pavel

    2015-10-28

    Dissociation energies (D0) of 11 H-bonded and 11 dispersion-bound complexes were calculated as the sum of interaction energies and the change of zero-point vibrational energies (ΔZPVE). The structures of H-bonded complexes were optimized at the RI-MP2/cc-pVTZ level, at which deformation and harmonic ΔZPVE energies were also calculated. The structures of dispersion-bound complexes were optimized at the DFT-D3 level, and harmonic ΔZPVE energies were determined at the same level as well. For comparison, CCSD(T)/CBS D0 energies were also evaluated for both types of complexes. The CCSD(T)/CBS interaction energy was constructed as the sum of MP2/CBS interaction energy, extrapolated from aug-cc-pVTZ and aug-cc-pVQZ basis sets, and ΔCCSD(T) correction, determined with the aug-cc-pVDZ basis set. The ΔZPVE energies were determined for all complexes at the harmonic level and for selected complexes, these energies were also calculated using second-order vibration perturbation (VPT2) theory. For H-bonded complexes, the harmonic CCSD(T)/CBS D0 energies were in better agreement with the experimental values (with a mean relative error (MRE) of 6.2%) than the RI-MP2/cc-pVTZ D0 (a MRE of 12.3%). The same trend was found for dispersion-bound complexes (6.2% (MRE) at CCSD(T)/CBS and 7.7% (MRE) at the DFT-D3 level). When the anharmonic ΔZPVE term was included instead of harmonic one, the agreement between theoretical and experimental D0 deteriorated for H-bonded as well as dispersion-bound complexes. Finally, the applicability of "diagonal approximation" for determining the anharmonic ΔZPVE was shown. For the phenolH2O complex, the ΔZPVE energy calculated at the VPT2 level and on the basis of "diagonal approximation" differed by less than 0.1 kcal mol(-1). PMID:26392236

  2. Energies and excited-state dynamics of 1Bu+, 1Bu- and 3Ag- states of carotenoids bound to LH2 antenna complexes from purple photosynthetic bacteria

    Science.gov (United States)

    Christiana, Rebecca; Miki, Takeshi; Kakitani, Yoshinori; Aoyagi, Shiho; Koyama, Yasushi; Limantara, Leenawaty

    2009-10-01

    Time-resolved pump-probe stimulated-emission and transient-absorption spectra were recorded after excitation with ˜30 fs pulses to the 1Bu+(0) and optically-forbidden diabatic levels of carotenoids, neurosporene, spheroidene and lycopene having n = 9-11 double bonds, bound to LH2 antenna complexes from Rhodobacter sphaeroides G1C, 2.4.1 and Rhodospirillum molischianum. The low-energy shift of stimulated emission from the covalent 1Bu-(0) and 3Ag-(0) levels slightly larger than that from the ionic 1Bu+(0) state suggests the polarization, whereas more efficient triplet generation suggests the twisting of the conjugated chain in Cars bound to the LH2 complexes, when compared to Cars free in solution.

  3. Functional Feed Assessment on Litopenaeus vannamei Using 100% Fish Meal Replacement by Soybean Meal, High Levels of Complex Carbohydrates and Bacillus Probiotic Strains

    OpenAIRE

    Rosalia Contreras; Jesus Paniagua-Michel; Leonel Ochoa; Jorge Olmos

    2011-01-01

    Functional feed supplemented with alternative-economic nutrient sources (protein, carbohydrates, lipids) and probiotics are being considered in shrimp/fish aquaculture production systems as an option to increase yield and profits and to reduce water pollution. In this study the probiotic potential to formulate functional feeds have been evaluated using four dietary treatments: Treatment 1 (B + Bs); Bacillus subtilis potential probiotic strain was supplemented to a soybeanmeal (SBM)—carbohydra...

  4. Functional Feed Assessment on Litopenaeus vannamei Using 100% Fish Meal Replacement by Soybean Meal, High Levels of Complex Carbohydrates and Bacillus Probiotic Strains

    Directory of Open Access Journals (Sweden)

    Rosalia Contreras

    2011-06-01

    Full Text Available Functional feed supplemented with alternative-economic nutrient sources (protein, carbohydrates, lipids and probiotics are being considered in shrimp/fish aquaculture production systems as an option to increase yield and profits and to reduce water pollution. In this study the probiotic potential to formulate functional feeds have been evaluated using four dietary treatments: Treatment 1 (B + Bs; Bacillus subtilis potential probiotic strain was supplemented to a soybeanmeal (SBM—carbohydrates (CHO basal feed. Treatment 2 (B + Bm; Bacillus megaterium potential probiotic strain was supplemented to the same SBM-CHO basal feed. In Treatment 3 (B; SBM-CHO basal feed was not supplemented with probiotic strains. Treatment 4 (C; fishmeal commercial feed (FM was utilized as positive control. Feeding trials evaluated the survival, growth, and food conversion ratio and stress tolerance of juvenile Litopenaeus vannamei (Boone Pacific white shrimp. Best overall shrimp performance was observed for animals fed with Treatment 1 (B+Bs; additionally, stress tolerance and hemolymph metabolites also showed the best performance in this treatment. SBM-CHO basal feed not supplemented with probiotic strains (B presented smaller growth and lower feed conversion ratio (FCR. Shrimps fed with the fishmeal commercial feed (C presented the lowest stress tolerance to high ammonia and low oxygen levels. Specifically selected B. subtilis strains are recommended to formulate functional and economical feeds containing high levels of vegetable; protein and carbohydrates as main dietary sources in L. vannamei cultures.

  5. Functional feed assessment on Litopenaeus vannamei using 100% fish meal replacement by soybean meal, high levels of complex carbohydrates and Bacillus probiotic strains.

    Science.gov (United States)

    Olmos, Jorge; Ochoa, Leonel; Paniagua-Michel, Jesus; Contreras, Rosalia

    2011-01-01

    Functional feed supplemented with alternative-economic nutrient sources (protein, carbohydrates, lipids) and probiotics are being considered in shrimp/fish aquaculture production systems as an option to increase yield and profits and to reduce water pollution. In this study the probiotic potential to formulate functional feeds have been evaluated using four dietary treatments: Treatment 1 (B + Bs); Bacillus subtilis potential probiotic strain was supplemented to a soybeanmeal (SBM)-carbohydrates (CHO) basal feed. Treatment 2 (B + Bm); Bacillus megaterium potential probiotic strain was supplemented to the same SBM-CHO basal feed. In Treatment 3 (B); SBM-CHO basal feed was not supplemented with probiotic strains. Treatment 4 (C); fishmeal commercial feed (FM) was utilized as positive control. Feeding trials evaluated the survival, growth, and food conversion ratio and stress tolerance of juvenile Litopenaeus vannamei (Boone) Pacific white shrimp. Best overall shrimp performance was observed for animals fed with Treatment 1 (B+Bs); additionally, stress tolerance and hemolymph metabolites also showed the best performance in this treatment. SBM-CHO basal feed not supplemented with probiotic strains (B) presented smaller growth and lower feed conversion ratio (FCR). Shrimps fed with the fishmeal commercial feed (C) presented the lowest stress tolerance to high ammonia and low oxygen levels. Specifically selected B. subtilis strains are recommended to formulate functional and economical feeds containing high levels of vegetable; protein and carbohydrates as main dietary sources in L. vannamei cultures. PMID:21747750

  6. Bounded Earthquakes

    OpenAIRE

    Saric, Dragomir

    2006-01-01

    We give a short proof of the fact that bounded earthquakes of the unit disk induce quasisymmetric maps of the unit circle. By a similar method, we show that symmetric maps are induced by bounded earthquakes with asymptotically trivial measures.

  7. Analysis and validation of carbohydrate three-dimensional structures

    International Nuclear Information System (INIS)

    The article summarizes the information that is gained from and the errors that are found in carbohydrate structures in the Protein Data Bank. Validation tools that can locate these errors are described. Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein–carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein–carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures

  8. Crystal structures of complexes containing domains from two viral internal ribosome entry site (IRES) RNAs bound to the 70S ribosome

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jianyu; Korostelev, Andrei; Costantino, David A.; Donohue, John P.; Noller, Harry F.; Kieft, Jeffrey S. (UCSC); (Colorado)

    2011-08-24

    Internal ribosome entry site (IRES) RNAs are elements of viral or cellular mRNAs that bypass steps of canonical eukaryotic cap-dependent translation initiation. Understanding of the structural basis of IRES mechanisms is limited, partially due to a lack of high-resolution structures of IRES RNAs bound to their cellular targets. Prompted by the universal phylogenetic conservation of the ribosomal P site, we solved the crystal structures of proposed P site binding domains from two intergenic region IRES RNAs bound to bacterial 70S ribosomes. The structures show that these IRES domains nearly perfectly mimic a tRNA-mRNA interaction. However, there are clear differences in the global shape and position of this IRES domain in the intersubunit space compared to those of tRNA, supporting a mechanism for IRES action that invokes hybrid state mimicry to drive a noncanonical mode of translocation. These structures suggest how relatively small structured RNAs can manipulate complex biological machines.

  9. ParAB Partition Dynamics in Firmicutes: Nucleoid Bound ParA Captures and Tethers ParB-Plasmid Complexes

    OpenAIRE

    Lioy, Virginia S.; Andrea Volante; Nora E Soberón; Rudi Lurz; Silvia Ayora; Alonso, Juan C.

    2015-01-01

    In Firmicutes, small homodimeric ParA-like (δ2) and ParB-like (ω2) proteins, in concert with cis-acting plasmid-borne parS and the host chromosome, secure stable plasmid inheritance in a growing bacterial population. This study shows that (ω:YFP)2 binding to parS facilitates plasmid clustering in the cytosol. (δ:GFP)2 requires ATP binding but not hydrolysis to localize onto the cell's nucleoid as a fluorescent cloud. The interaction of (δ:CFP)2 or δ2 bound to the nucleoid with (ω:YFP)2 foci f...

  10. Insulin and carbohydrate dysregulation.

    Science.gov (United States)

    Gelato, Marie C

    2003-04-01

    Patients with human immunodeficiency virus receiving highly active antiretroviral therapy (HAART) may experience abnormal body composition changes as well as metabolic abnormalities, including dyslipidemia, increases in triglycerides, low high-density lipoprotein cholesterol levels, and abnormal carbohydrate metabolism, ranging from insulin resistance with and without glucose intolerance to frank diabetes. Whether the body composition changes (i.e., increased visceral adiposity and fat wasting in the peripheral tissues) are linked to abnormalities in carbohydrate metabolism is unclear. The use of HAART with and without therapy with protease inhibitors (PIs) is related to carbohydrate abnormalities and changes in body composition. Regimens that include PIs appear to have a higher incidence of insulin resistance (up to 90%) and diabetes mellitus (up to 40%). The etiology of these abnormalities is not well understood; what is known about insulin and carbohydrate dysregulation with HAART is discussed. PMID:12652377

  11. Tools for glycomics: mapping interactions of carbohydrates in biological systems.

    Science.gov (United States)

    Ratner, Daniel M; Adams, Eddie W; Disney, Matthew D; Seeberger, Peter H

    2004-10-01

    The emerging field of glycomics has been challenged by difficulties associated with studying complex carbohydrates and glycoconjugates. Advances in the development of synthetic tools for glycobiology are poised to overcome some of these challenges and accelerate progress towards our understanding of the roles of carbohydrates in biology. Carbohydrate microarrays, fluorescent neoglycoconjugate probes, and aminoglycoside antibiotic microarrays are among the many new tools becoming available to glycobiologists. PMID:15457538

  12. Structure of the exon junction core complex with a trapped DEAD-box ATPase bound to RNA

    DEFF Research Database (Denmark)

    Andersen, Christian Brix Folsted; Ballut, Lionel; Johansen, Jesper Sanderhoff;

    2006-01-01

    In higher eukaryotes, a multiprotein exon junction complex is deposited on spliced messenger RNAs. The complex is organized around a stable core, which serves as a binding platform for numerous factors that influence messenger RNA function. Here, we present the crystal structure of a tetrameric...

  13. Structure of the DNA-bound BRCA1 C-terminal Region from Human Replication Factor C p140 and Model of the Protein-DNA Complex

    OpenAIRE

    2010-01-01

    BRCA1 C-terminal domain (BRCT)-containing proteins are found widely throughout the animal and bacteria kingdoms where they are exclusively involved in cell cycle regulation and DNA metabolism. Whereas most BRCT domains are involved in protein-protein interactions, a small subset has bona fide DNA binding activity. Here, we present the solution structure of the BRCT region of the large subunit of replication factor C bound to DNA and a model of the structure-specific complex with 5′-phosphoryl...

  14. Cellular Delivery of Quantum Dot-Bound Hybridization Probe for Detection of Intracellular Pre-MicroRNA Using Chitosan/Poly(γ-Glutamic Acid) Complex as a Carrier

    OpenAIRE

    Yao Geng; Dajie Lin; Lijia Shao; Feng Yan; Huangxian Ju

    2013-01-01

    A quantum dot (QD)-bound hybridization probe was designed for detection of intracellular pre-miRNA using chitosan (CS)/poly(γ-glutamic acid) (γ-PGA) complex as a gene vector. The probe was prepared by assembling thiolated RNA to gold nanoparticle (Au NP) via Au-S bond and then binding 3'-end amine of the RNA to the carboxy group capped on quantum dot surface. The QD-RNA-Au NP probe was assembled on the vector by mixing with aqueous γ-PGA solution and then CS solution to construct a gene deliv...

  15. MCM-41 Bound Ruthenium Complex as Heterogeneous Catalyst for Hydrogenation Ⅰ: Effect of Support, Ligand and Solvent on the Catalyst Performance

    Institute of Scientific and Technical Information of China (English)

    YU, Ying-Min; FEI, Jin-Hua; ZHANG, Yi-Ping; ZHENG, Xiao-Ming

    2006-01-01

    The functionalized MCM-41 mesoporous bound ruthenium complex was synthesized and characterized using elemental analysis, atomic absorption spectrophotometer, BET, XRD and FTIR. Hydrogenation of carbon dioxide to formic acid was investigated over these catalysts under supercritical CO2 condition. The effect of reactant gas partial pressure, supports, solvents and ligands on the synthesis of formic acid was studied. These factors could influence the catalyst activity, stability and reuse performance greatly and no byproduct was detected. These promising catalysts also offered the industrial advantages such as easy separation.

  16. Dietary Carbohydrates and Childhood Functional Abdominal Pain.

    Science.gov (United States)

    Chumpitazi, Bruno P; Shulman, Robert J

    2016-01-01

    Childhood functional gastrointestinal disorders (FGIDs) affect a large number of children throughout the world. Carbohydrates (which provide the majority of calories consumed in the Western diet) have been implicated both as culprits for the etiology of symptoms and as potential therapeutic agents (e.g., fiber) in childhood FGIDs. In this review, we detail how carbohydrate malabsorption may cause gastrointestinal symptoms (e.g., bloating) via the physiologic effects of both increased osmotic activity and increased gas production from bacterial fermentation. Several factors may play a role, including: (1) the amount of carbohydrate ingested; (2) whether ingestion is accompanied by a meal or other food; (3) the rate of gastric emptying (how quickly the meal enters the small intestine); (4) small intestinal transit time (the time it takes for a meal to enter the large intestine after first entering the small intestine); (5) whether the meal contains bacteria with enzymes capable of breaking down the carbohydrate; (6) colonic bacterial adaptation to one's diet, and (7) host factors such as the presence or absence of visceral hypersensitivity. By detailing controlled and uncontrolled trials, we describe how there is a general lack of strong evidence supporting restriction of individual carbohydrates (e.g., lactose, fructose) for childhood FGIDs. We review emerging evidence suggesting that a more comprehensive restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) may be effective. Finally, we review how soluble fiber (a complex carbohydrate) supplementation via randomized controlled intervention trials in childhood functional gastrointestinal disorders has demonstrated efficacy. PMID:27355647

  17. Platinum(II) and platinum(IV) complexes stabilized by abnormal/mesoionic C4-bound dicarbenes

    OpenAIRE

    Khlebnikov, Vsevolod; Heckenroth, Marion; Müller-Bunz, Helge; Albrecht, Martin

    2013-01-01

    Platinum(II) complexes comprising abnormal diimidazolylidene ligands were synthesized from cis-PtMe2(DMSO)(2) using microwave-assisted double C-H bond activation. NMR analysis revealed an unusual solvolysis process, induced by coordinating solvents such as DMSO and MeCN, which has not been observed in related normal dicarbene complexes. NMR and IR spectroscopy and crystallographic analysis of the mono-substituted DMSO complex indicate a sulfur-bonding of the DMSO ligand to the platinum(II) ce...

  18. Effects of isolated and complex dietary fibre matrices in breads on carbohydrate digestibility and physicochemical properties of ileal effluent from pigs

    DEFF Research Database (Denmark)

    Kasprzak, Miroslaw Marek; Lærke, Helle Nygaard; Knudsen, Knud Erik Bach

    2012-01-01

    To assess the effects of content and structure of dietary fiber (DF) on the carbohydrate digestibility and physicochemical properties of ileal digesta, five bread diets were studied in an experiment with ileum-cannulated pigs in a crossover design. The diets consisted of two experimental breads...... effect of either DF content, structure, viscosity, or water-binding capacity on the ileal digestibility of starch, which was almost completely digested in the small intestine. Arabinoxylan and β-glucan were 11 and 81% degraded in the ileum, respectively, which resulted in a significant increase and...... decrease of ileal extract viscosities, respectively. It is concluded that the viscosity-elevating properties of soluble DF in breads and ileal digesta are strongly dependent on the content and structure of DF and degree of resistance toward microbial enzymes....

  19. A flow calculus of mwp-bounds for complexity analysis

    DEFF Research Database (Denmark)

    Jones, Neil D.; Kristiansen, Lars

    2010-01-01

    We present a method for certifying that the values computed by an imperative program will be bounded by polynomials in the program's inputs. To this end, we introduce mwp-matrices and define a semantic relation ⊧ C : M, where C is a program and M is an mwp-matrix. It follows...... : M is the bottom line. We prove that ⊢ C : M implies ⊧ C : M. By means of exhaustive proof search, an algorithm can decide if there exists M such that the relation ⊢ C : M holds, and thus, our results yield a computational method....

  20. Diarrhea caused by carbohydrate malabsorption.

    Science.gov (United States)

    Hammer, Heinz F; Hammer, Johann

    2012-09-01

    This article will focus on the role of the colon in the pathogenesis of diarrhea in carbohydrate malabsorption or physiologically incomplete absorption of carbohydrates, and on the most common manifestation of carbohydrate malabsorption, lactose malabsorption. In addition, incomplete fructose absorption, the role of carbohydrate malabsorption in other malabsorptive diseases, and congenital defects that lead to malabsorption will be covered. The article concludes with a section on diagnostic tools to evaluate carbohydrate malabsorption. PMID:22917167

  1. Purification and properties of an extremely thermostable membrane-bound sulfur-reducing complex from the hyperthermophilic Pyrodictium abyssi.

    Science.gov (United States)

    Dirmeier, R; Keller, M; Frey, G; Huber, H; Stetter, K O

    1998-03-15

    The chemolithoautotrophic archaeon Pyrodictium abyssi isolate TAG 11 gains energy by reducing sulfur with H2 to H2S. From this hyperthermophile, a sulfur-reducing complex catalyzing this reaction was purified 13.5-fold. The native complex exhibited a brownish-yellow colour and showed an apparent molecular mass of 520 kDa. SDS/PAGE revealed the presence of nine different major polypeptides with apparent molecular masses of 82, 72, 65, 50, 47, 42, 40, 30 and 24 kDa. The native complex contained 50-55 mol acid-labile sulfur, 50-55 mol iron, 1.6 mol nickel, 1.2 mol copper, 2.8 mol cytochrome b and 0.3 mol cytochrome c (all per mol native complex). The temperature optimum of the H2:sulfur oxidoreductase complex was 100 degrees C, which is consistent with the physiological growth optimum of the native organism. The complex is extremely heat stable. During 5 h incubation at 100 degrees C, no decrease in H2S-forming activity could be observed. PMID:9546664

  2. The aerobic respiratory chain of the acidophilic archaeon Ferroplasma acidiphilum: A membrane-bound complex oxidizing ferrous iron.

    Science.gov (United States)

    Castelle, Cindy J; Roger, Magali; Bauzan, Marielle; Brugna, Myriam; Lignon, Sabrina; Nimtz, Manfred; Golyshina, Olga V; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne

    2015-08-01

    The extremely acidophilic archaeon Ferroplasma acidiphilum is found in iron-rich biomining environments and is an important micro-organism in naturally occurring microbial communities in acid mine drainage. F. acidiphilum is an iron oxidizer that belongs to the order Thermoplasmatales (Euryarchaeota), which harbors the most extremely acidophilic micro-organisms known so far. At present, little is known about the nature or the structural and functional organization of the proteins in F. acidiphilum that impact the iron biogeochemical cycle. We combine here biochemical and biophysical techniques such as enzyme purification, activity measurements, proteomics and spectroscopy to characterize the iron oxidation pathway(s) in F. acidiphilum. We isolated two respiratory membrane protein complexes: a 850 kDa complex containing an aa3-type cytochrome oxidase and a blue copper protein, which directly oxidizes ferrous iron and reduces molecular oxygen, and a 150 kDa cytochrome ba complex likely composed of a di-heme cytochrome and a Rieske protein. We tentatively propose that both of these complexes are involved in iron oxidation respiratory chains, functioning in the so-called uphill and downhill electron flow pathways, consistent with autotrophic life. The cytochrome ba complex could possibly play a role in regenerating reducing equivalents by a reverse ('uphill') electron flow. This study constitutes the first detailed biochemical investigation of the metalloproteins that are potentially directly involved in iron-mediated energy conservation in a member of the acidophilic archaea of the genus Ferroplasma. PMID:25896560

  3. Dynamics of dipole- and valence bound anions in iodide-adenine binary complexes: A time-resolved photoelectron imaging and quantum mechanical investigation

    International Nuclear Information System (INIS)

    Dipole bound (DB) and valence bound (VB) anions of binary iodide-adenine complexes have been studied using one-color and time-resolved photoelectron imaging at excitation energies near the vertical detachment energy. The experiments are complemented by quantum chemical calculations. One-color spectra show evidence for two adenine tautomers, the canonical, biologically relevant A9 tautomer and the A3 tautomer. In the UV-pump/IR-probe time-resolved experiments, transient adenine anions can be formed by electron transfer from the iodide. These experiments show signals from both DB and VB states of adenine anions formed on femto- and picosecond time scales, respectively. Analysis of the spectra and comparison with calculations suggest that while both the A9 and A3 tautomers contribute to the DB signal, only the DB state of the A3 tautomer undergoes a transition to the VB anion. The VB anion of A9 is higher in energy than both the DB anion and the neutral, and the VB anion is therefore not accessible through the DB state. Experimental evidence of the metastable A9 VB anion is instead observed as a shape resonance in the one-color photoelectron spectra, as a result of UV absorption by A9 and subsequent electron transfer from iodide into the empty π-orbital. In contrast, the iodide-A3 complex constitutes an excellent example of how DB states can act as doorway state for VB anion formation when the VB state is energetically available

  4. Dynamics of dipole- and valence bound anions in iodide-adenine binary complexes: A time-resolved photoelectron imaging and quantum mechanical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Stephansen, Anne B. [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 København Ø (Denmark); King, Sarah B.; Li, Wei-Li; Kunin, Alice [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Yokoi, Yuki; Minoshima, Yusuke; Takayanagi, Toshiyuki [Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570 (Japan); Neumark, Daniel M., E-mail: dneumark@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-09-14

    Dipole bound (DB) and valence bound (VB) anions of binary iodide-adenine complexes have been studied using one-color and time-resolved photoelectron imaging at excitation energies near the vertical detachment energy. The experiments are complemented by quantum chemical calculations. One-color spectra show evidence for two adenine tautomers, the canonical, biologically relevant A9 tautomer and the A3 tautomer. In the UV-pump/IR-probe time-resolved experiments, transient adenine anions can be formed by electron transfer from the iodide. These experiments show signals from both DB and VB states of adenine anions formed on femto- and picosecond time scales, respectively. Analysis of the spectra and comparison with calculations suggest that while both the A9 and A3 tautomers contribute to the DB signal, only the DB state of the A3 tautomer undergoes a transition to the VB anion. The VB anion of A9 is higher in energy than both the DB anion and the neutral, and the VB anion is therefore not accessible through the DB state. Experimental evidence of the metastable A9 VB anion is instead observed as a shape resonance in the one-color photoelectron spectra, as a result of UV absorption by A9 and subsequent electron transfer from iodide into the empty π-orbital. In contrast, the iodide-A3 complex constitutes an excellent example of how DB states can act as doorway state for VB anion formation when the VB state is energetically available.

  5. KINETIC STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A NOVEL COPOLYMER- BOUND CIS- DICARBONYLRHODIUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuying; YUAN Guoqing; CHEN Rongyao

    1989-01-01

    The kinetic study of carbonylation of methanol-acetic acid mixture to acetic acid and acetic anhydride over a cis-dicarbonylrhodium complex (MVM' Rh)coordinated with the ethylene diacrylate (M')crosslinked copolymer of methyl acrylate (M) and 2 - vinylpyridine (V) shows that the rate of reaction is zero order with respect to both reactants methanol and carbon monoxide, but first order in the concentrations of promoter methyl iodide and rhodium in the complex . Polar solvents can accelerate the reaction .Activation parameters were calculated from the experimental results, being comparable to that of the homogeneous system . A mechanism similar to that of soluble rhodium catalyst was proposed .

  6. Energy transfer in solution-based complexes of CdTe nanocrystals electrostatically bound by calcium ions

    International Nuclear Information System (INIS)

    Colloidal semiconductor nanocrystals with controllable surface properties are attractive objects for use as building blocks in different functional structures within the bottom-up assembly approach. We produced stable complexes from differently-sized water soluble CdTe nanocrystals capped by mercaptoacid stabilizers through electrostatic interactions of negatively charged carboxylic groups of capping ligands with positively charged Ca(II) cations. Energy transfer between smaller nanocrystals (donors) and larger nanocrystals (acceptors) in fabricated complexes is demonstrated by means of steady-state and time-resolved photoluminescence spectroscopy, paving the way to nanocrystal-based light harvesting structures

  7. Crystal structure of the deglycating enzyme Amadoriase I in its free form and substrate-bound complex.

    Science.gov (United States)

    Rigoldi, Federica; Gautieri, Alfonso; Dalle Vedove, Andrea; Lucarelli, Anna Paola; Vesentini, Simone; Parisini, Emilio

    2016-06-01

    Amadoriases, also known as fructosyl amine oxidases (FAOX), are enzymes that catalyze the de-glycosylation of fructosyl amino acids. As such, they are excellent candidates for the development of enzyme-based diagnostic and therapeutic tools against age- and diabetes-induced protein glycation. However, mostly because of the lack of a complete structural characterization of the different members of the family, the molecular bases of their substrate specificity have yet to be fully understood. The high resolution crystal structures of the free and the substrate-bound form of Amadoriase I shown herein allow for the identification of key structural features that account for the diverse substrate specificity shown by this class of enzymes. This is of particular importance in the context of the rather limited and partially incomplete structural information that has so far been available in the literature on the members of the FAOX family. Moreover, using molecular dynamics simulations, we describe the tunnel conformation and the free energy profile experienced by the ligand in going from bulk water to the catalytic cavity, showing the presence of four gating helices/loops, followed by an "L-shaped" narrow cavity. In summary, the tridimensional architecture of Amadoriase I presented herein provides a reference structural framework for the design of novel enzymes for diabetes monitoring and protein deglycation. Proteins 2016; 84:744-758. © 2016 Wiley Periodicals, Inc. PMID:26873906

  8. Polymer-bound oxidovanadium(IV) and dioxidovanadium(V) complexes as catalysts for the oxidative desulfurization of model fuel diesel.

    Science.gov (United States)

    Maurya, Mannar R; Arya, Aarti; Kumar, Amit; Kuznetsov, Maxim L; Avecilla, Fernando; Costa Pessoa, João

    2010-07-19

    The Schiff base (Hfsal-dmen) derived from 3-formylsalicylic acid and N,N-dimethyl ethylenediamine has been covalently bonded to chloromethylated polystyrene to give the polymer-bound ligand, PS-Hfsal-dmen (I). Treatment of PS-Hfsal-dmen with [V(IV)O(acac)(2)] in the presence of MeOH gave the oxidovanadium(IV) complex PS-[V(IV)O(fsal-dmen)(MeO)] (1). On aerial oxidation in methanol, complex 1 was oxidized to PS-[V(V)O(2)(fsal-dmen)] (2). The corresponding neat complexes, [V(IV)O(sal-dmen)(acac)] (3) and [V(V)O(2)(sal-dmen)] (4) were similarly prepared. All these complexes are characterized by various spectroscopic techniques (IR, electronic, NMR, and electron paramagnetic resonance (EPR)) and thermal as well as field-emission scanning electron micrographs (FE-SEM) studies, and the molecular structures of 3 and 4 were determined by single crystal X-ray diffraction. The EPR spectrum of the polymer supported V(IV)O-complex 1 is characteristic of magnetically diluted V(IV)O-complexes, the resolved EPR pattern indicating that the V(IV)O-centers are well dispersed in the polymer matrix. A good (51)V NMR spectrum could also be measured with 4 suspended in dimethyl sulfoxide (DMSO), the chemical shift (-503 ppm) being compatible with a VO(2)(+)-center and a N,O binding set. The catalytic oxidative desulfurization of organosulfur compounds thiophene, dibenzothiophene, benzothiophene, and 2-methyl thiophene (model of fuel diesel) was carried out using complexes 1 and 2. The sulfur in model organosulfur compounds oxidizes to the corresponding sulfone in the presence of H(2)O(2). The systems 1 and 2 do not loose efficiency for sulfoxidation at least up to the third cycle of reaction, this indicating that they preserve their integrity under the conditions used. Plausible intermediates involved in these catalytic processes are established by UV-vis, EPR, (51)V NMR, and density functional theory (DFT) studies, and an outline of the mechanism is proposed. The (51)V NMR spectra

  9. Crystallization and preliminary X-ray crystallographic analysis of Thermus thermophilus transcription elongation complex bound to Gfh1

    International Nuclear Information System (INIS)

    To elucidate which RNA polymerase structural state a particular T. thermophilus Gre-family protein (Gfh1) associates with, the T. thermophilus RNAP elongation complex was cocrystallized with Gfh1. RNA polymerase (RNAP) elongates RNA by iterative nucleotide-addition cycles (NAC). A specific structural state (or states) of RNAP may be the target of transcription elongation factors. Gfh1, a Thermus thermophilus Gre-family protein, inhibits NAC. To elucidate which RNAP structural state Gfh1 associates with, the T. thermophilus RNAP elongation complex (EC) was cocrystallized with Gfh1. Of the 70 DNA/RNA scaffolds tested, two (for EC1 and EC2) were successfully crystallized. In the presence of Gfh1, EC1 and EC2 yielded crystals belonging to space group P21 with similar unit-cell parameters (crystals 1 and 2, respectively). X-ray diffraction data sets were obtained at 3.6 and 3.8 Å resolution, respectively

  10. A NOVEL COPOLYMER-BOUND CIS- DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

    Institute of Scientific and Technical Information of China (English)

    YUAN Guoqing; CHEN Yuying; CHEN Rongyao

    1989-01-01

    A series of porous microspheres of linear and ethylene diacrylate (M ') cross-linked copolymers of 2 - vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol - acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.

  11. Inactivation of lacZ gene expression by UV light and bound DNA photolyase implies formation of extended complexes in the genomes of specific Escherichia coli strains

    International Nuclear Information System (INIS)

    In Escherichia coli strains WU and CS101, UV inactivation of lacZ gene expression is more effective when the cells contain amplified DNA photolyase, and flash photoreactivation (fPR) after 15 min of metabolism does not reverse inactivation by the photolyasedimer complexes. In other strains, also studied with or without amplified DNA photolyase, there is no differential UV inactivation and fPR reverses inactivation by the complexes regardless of continued metabolism. The irreparable condition in strain WU is not due to dysfunction of photolyase: during post-UV metabolism, fPR still restores viability and dimers are removed from the region of the lac operon. When the wild-type lac promoter is replaced by the UV5 promoter, making expression insensitive to relaxed supercoiling and catabolite repression, inactivation by dimers alone becomes more resistant, i.e. requires higher fluences, but inactivation in WU and CS101 is still exceptionally sensitive to photolyasedimer complexes. This indicates that dimers external to the wild-type lac operon may inhibit expression by altering supercoiling but that complexes must involve some other mechanism for their special effect in WU and CS101. The exceptionally efficient inactivation and irreparable condition are consistent with the idea that, in two specific laboratory strains, photolyase bound to dimers at a considerable distance from the lac operon may initiate an aggregation of DNA with other cellular molecules that extends to, and inactivates expression from, the operon

  12. Bounding the $\

    CERN Document Server

    Gutiérrez-Rodríguez, A

    2003-01-01

    A bound on the nu /sup tau / magnetic moment is calculated through the reaction e/sup +/e/sup -/ to nu nu gamma at the Z/sub 1/-pole, and in the framework of a left-right symmetric model at LEP energies. We find that the bound is almost independent of the mixing angle phi of the model in the allowed experimental range for this parameter. (31 refs).

  13. Chitosan-bound pyridinedicarboxylate Ni(II) and Fe(III) complex biopolymer films as waste water decyanidation agents.

    Science.gov (United States)

    Adewuyi, Sheriff; Jacob, Julianah Modupe; Olaleye, Oluwatoyin Omolola; Abdulraheem, Taofiq Olanrewaju; Tayo, Jubril Ayopo; Oladoyinbo, Fatai Oladipupo

    2016-10-20

    Chitosan is a biopolymer with immense structural advantage for chemical and mechanical modifications to generate novel properties, functions and applications. This work depicts new pyridinedicarboxylicacid (PDC) crosslinked chitosan-metal ion films as veritable material for cyanide ion removal from aqueous solution. The PDC-crosslinked chitosan-metal films (PDC-Chit-Ni(II) and PDC-Chit-Fe(III)) were formed by complexing PDC-crosslinked chitosan film with anhydrous nickel(II) and iron(III) chloride salts respectively. The PDC-Chit and its metal films were characterized employing various analytical and spectroscopic techniques. The FT-IR, UV-vis and the XRD results confirm the presence of the metal ions in the metal coordinated PDC-crosslinked chitosan film. The surface morphological difference of PDC-Chit-Ni(II) film before and after decyanidation was explored with scanning electron microscopy. Furthermore, the quantitative amount of nickel(II) and iron(III) present in the complex were determined using Atomic Absorption Spectrophotometer as 32.3 and 37.2μg/g respectively which portends the biopolymer film as a good complexing agent. Removal of cyanide from aqueous solution with PDC-Chit, PDC-Chit-Ni(II) and PDC-Chit-Fe(III) films was studied with batch equilibrium experiments. At equilibrium, decyanidation capacity (DC) followed the order PDC-Chit-Ni (II)≈PDC-Chit-Fe(III)>PDC-Chit. PDC-Chit-Ni(II) film gave 100% CN(-) removal within 40min decyanidation owing to favorable coordination geometry. PMID:27474675

  14. Crystal structures of complexes containing domains from two viral internal ribosome entry site (IRES) RNAs bound to the 70S ribosome.

    Science.gov (United States)

    Zhu, Jianyu; Korostelev, Andrei; Costantino, David A; Donohue, John P; Noller, Harry F; Kieft, Jeffrey S

    2011-02-01

    Internal ribosome entry site (IRES) RNAs are elements of viral or cellular mRNAs that bypass steps of canonical eukaryotic cap-dependent translation initiation. Understanding of the structural basis of IRES mechanisms is limited, partially due to a lack of high-resolution structures of IRES RNAs bound to their cellular targets. Prompted by the universal phylogenetic conservation of the ribosomal P site, we solved the crystal structures of proposed P site binding domains from two intergenic region IRES RNAs bound to bacterial 70S ribosomes. The structures show that these IRES domains nearly perfectly mimic a tRNA • mRNA interaction. However, there are clear differences in the global shape and position of this IRES domain in the intersubunit space compared to those of tRNA, supporting a mechanism for IRES action that invokes hybrid state mimicry to drive a noncanonical mode of translocation. These structures suggest how relatively small structured RNAs can manipulate complex biological machines. PMID:21245352

  15. Characterization and reactivity of the weakly bound complexes of the [H, N, S]− anionic system with astrophysical and biological implications

    International Nuclear Information System (INIS)

    We investigate the lowest electronic states of doublet and quartet spin multiplicity states of HNS− and HSN− together with their parent neutral triatomic molecules. Computations were performed using highly accurate ab initio methods with a large basis set. One-dimensional cuts of the full-dimensional potential energy surfaces (PESs) along the interatomic distances and bending angle are presented for each isomer. Results show that the ground anionic states are stable with respect to the electron detachment process and that the long range parts of the PESs correlating to the SH− + N, SN− + H, SN + H−, NH + S−, and NH− + S are bound. In addition, we predict the existence of long-lived weakly bound anionic complexes that can be formed after cold collisions between SN− and H or SH− and N. The implications for the reactivity of these species are discussed; specifically, it is shown that the reactions involving SH−, SN−, and NH− lead either to the formation of HNS− or HSN− in their electronic ground states or to autodetachment processes. Thus, providing an explanation for why the anions, SH−, SN−, and NH−, have limiting detectability in astrophysical media despite the observation of their corresponding neutral species. In a biological context, we suggest that HSN− and HNS− should be incorporated into H2S-assisted heme-catalyzed reduction mechanism of nitrites in vivo

  16. Subunit structure of the follitropin (FSH) receptor. Photoaffinity labeling of the membrane-bound receptor follitropin complex in situ

    International Nuclear Information System (INIS)

    Human follicle-stimulating hormone (hFSH) was acylated with N-hydroxysuccinimidyl-4-azidobenzoate (HSAB) and radioiodinated (55 microCi/micrograms) for use as a photoaffinity probe to investigate the subunit structure of the FSH receptor in calf testis. After incubation with the photoaffinity probe and photolysis with UV light, the cross-linked hormone-receptor complex was solubilized from the membrane and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence and absence of the reducing agent dithiothreitol. Autoradiography of the polyacrylamide gels revealed two major bands, 64 kDa and 84 kDa. These were equivalent in molecular mass to those observed in a previous study in which performed hormone-receptor complexes were solubilized with detergent prior to formation of covalent cross-linkages through the use of homobifunctional cross-linking reagents. Reduction with dithiothreitol resulted in the loss of radioactivity from the 84-kDa band with a concomitant increase in the intensity of the 64-kDa band. Since dithiothreitol increases the dissociation of intact radioiodinated azidobenzoyl-FSH into subunits, it is suggested that the conversion of the 84-kDa band to the 64-kDa band by dithiothreitol is due to the loss of non-cross-linked hFSH subunit from the 84-kDa band and that the two bands observed after photoaffinity labeling arise from covalent bond formation between hFSH and a receptor subunit having a relative molecular weight (Mr) of 48,000. In addition to the predominant photolabeling of the receptor to yield the 64-kDa and 84-kDa bands, several other, less intense bands (54 kDa, 76 kDa, 97 kDa, and 116 kDa) were also consistently observed on autoradiographs

  17. Carbohydrate polymers as constituents of exopolymer substances in seawater, their complexing properties towards copper ions, surface and catalytic activity determined by electrochemical methods.

    Science.gov (United States)

    Plavšić, Marta; Strmečki, Slađana

    2016-01-01

    The goal of this study was to investigate to which extent polysaccharides (PS) contribute to the complexing capacity for copper ion (LT), to determine their property of surface activity and evaluate their capability to cause the catalytic hydrogen evolution wave (peak "H") due to their adsorption and the catalytic groups in their structure. Complexing capacities and apparent stability constants (Kapp) were measured electrochemically for model polysaccharides (PS): carrageenans (κ-, ι- and λ-), chondroitin sulfate, dextran, dextran sulfate, Na-alginate and humic material. Cu-complexing capacities were determined for Na-alginate (logKapp=8.32) and chondroitin sulphate (logKapp=8.14). PS adsorb on different surfaces due to their amphyphylic properties and on that way they could increase the interaction of copper ions with these surfaces by forming the surface complexes with Cu ions. PMID:26453850

  18. Glycosyltransferase engineering for carbohydrate synthesis.

    Science.gov (United States)

    McArthur, John B; Chen, Xi

    2016-02-01

    Glycosyltransferases (GTs) are powerful tools for the synthesis of complex and biologically-important carbohydrates. Wild-type GTs may not have all the properties and functions that are desired for large-scale production of carbohydrates that exist in nature and those with non-natural modifications. With the increasing availability of crystal structures of GTs, especially those in the presence of donor and acceptor analogues, crystal structure-guided rational design has been quite successful in obtaining mutants with desired functionalities. With current limited understanding of the structure-activity relationship of GTs, directed evolution continues to be a useful approach for generating additional mutants with functionality that can be screened for in a high-throughput format. Mutating the amino acid residues constituting or close to the substrate-binding sites of GTs by structure-guided directed evolution (SGDE) further explores the biotechnological potential of GTs that can only be realized through enzyme engineering. This mini-review discusses the progress made towards GT engineering and the lessons learned for future engineering efforts and assay development. PMID:26862198

  19. Oxidized LDL-bound CD36 recruits a Na+/K+-ATPase-Lyn complex in macrophages that promotes atherosclerosis

    Science.gov (United States)

    Chen, Yiliang; Kennedy, David J.; Ramakrishnan, Devi Prasadh; Yang, Moua; Huang, Wenxin; Li, Zhichuan; Xie, Zijian; Chadwick, Alexandra C.; Sahoo, Daisy; Silverstein, Roy L.

    2016-01-01

    One characteristic of atherosclerosis is the accumulation of lipid-laden macrophage foam cells in the arterial wall. We have previously shown that the binding of oxidized LDL (oxLDL) to the scavenger receptor CD36 activates the kinase Lyn, initiating a cascade that inhibits macrophage migration and is necessary for foam cell generation. Here, we identified the plasma membrane ion transporter Na/K-ATPase as a key component in the macrophage oxLDL-CD36 signaling axis. Using peritoneal macrophages isolated from Atp1a1 heterozygous or Cd36 null mice, we demonstrated that CD36 recruited a Na/K-ATPase-Lyn complex for Lyn activation in response to oxLDL. Macrophages deficient in the α1 Na/K-ATPase catalytic subunit did not respond to activation of CD36, showing attenuated oxLDL uptake and foam cell formation, and oxLDL failed to inhibit migration of these macrophages. Furthermore, Apoe-null mice, which are a model of atherosclerosis, were protected from diet-induced atherosclerosis by global deletion of a single allele encoding the α1 Na+/K+-ATPase subunit or reconstitution with macrophages that lacked an allele encoding the α1 Na+/K+-ATPase subunit.. These findings identify Na/K-ATPase as a potential target for preventing or treating anti-atherosclerotic therapy. PMID:26350901

  20. On the role of charge transfer in the stabilization of weakly bound complexes involving water and hydrogen sulphide molecules

    International Nuclear Information System (INIS)

    Graphical abstract: A charge-displacement analysis allows to quantitatively assess charge-transfer effects in hydrogen-bonded complexes. Highlights: ► We compare water with hydrogen sulphide both interacting with krypton. ► In both cases the interaction possesses a definite charge transfer component. ► Charge-transfer differs slightly in the two systems and exhibits different stereoselectivity. - Abstract: Integral cross section data for collisions of water and hydrogen sulphide molecules with noble gas atoms, measured with the same apparatus under identical conditions and analyzed by exploiting the same potential model, provided a set of internally consistent potential parameters. Their critical comparison is exploited not only to identify those systems where the intermolecular bond is not simply due to the balancing of size repulsion with dispersion and induction attraction, but also to establish the amount of bond stabilization by charge-transfer effects. Such experimental findings are analyzed through extensive and accurate ab initio calculations, addressed at discovering the relevant differences in the basic features of the potential energy surfaces. In particular, we have analyzed in detail the prototype H2S, H2O–Kr systems and found pronounced differences in the dependence of the interaction nature and energy on the relative orientation of the colliding systems. Using the recently proposed charge-displacement analysis we have been able to quantitatively assess charge-transfer effects, which differ significantly in the two systems and exhibit different stereoselectivity. This casts further light on the specificity of water interactions.

  1. NMR investigations of protein-carbohydrate interactions : Studies on the relevance of Trp/Tyr variations in lectin binding sites as deduced from titration microcalorimetry and NMR studies on hevein domains. Determination of the NMR structure of the complex between pseudohevein and N,N ',N ''-triacetylchitotriose

    NARCIS (Netherlands)

    Asensio, JL; Siebert, HC; von der Lieth, CW; Laynez, J; Bruix, M; Soedjanaamadja, UM; Beintema, JJ; Canada, FJ; Gabius, HJ; Jimenez-Barbero, J

    2000-01-01

    Model studies on lectins and their interactions with carbohydrate ligands in solution are essential to gain insights into the driving forces for complex formation and to optimize programs for computer simulations. The specific interaction of pseudohevein with N,N',N"-triacetylchitotriose has been an

  2. Characterization and reactivity of the weakly bound complexes of the [H, N, S]{sup −} anionic system with astrophysical and biological implications

    Energy Technology Data Exchange (ETDEWEB)

    Trabelsi, T.; Ajili, Y.; Ben Yaghlane, S.; Jaidane, N.-E. [Laboratoire de Spectroscopie Atomique, Moléculaire et Applications–LSAMA, Université de Tunis El Manar, Tunis (Tunisia); Mogren Al-Mogren, M. [Chemistry Department, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Francisco, J. S. [Department of Chemistry and Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47906 (United States); Hochlaf, M., E-mail: hochlaf@univ-mlv.fr [Laboratoire Modélisation et Simulation Multi Echelle, Université Paris-Est, MSME UMR 8208 CNRS, 5 Blvd. Descartes, 77454 Marne-la-Vallée (France)

    2015-07-21

    We investigate the lowest electronic states of doublet and quartet spin multiplicity states of HNS{sup −} and HSN{sup −} together with their parent neutral triatomic molecules. Computations were performed using highly accurate ab initio methods with a large basis set. One-dimensional cuts of the full-dimensional potential energy surfaces (PESs) along the interatomic distances and bending angle are presented for each isomer. Results show that the ground anionic states are stable with respect to the electron detachment process and that the long range parts of the PESs correlating to the SH{sup −} + N, SN{sup −} + H, SN + H{sup −}, NH + S{sup −}, and NH{sup −} + S are bound. In addition, we predict the existence of long-lived weakly bound anionic complexes that can be formed after cold collisions between SN{sup −} and H or SH{sup −} and N. The implications for the reactivity of these species are discussed; specifically, it is shown that the reactions involving SH{sup −}, SN{sup −}, and NH{sup −} lead either to the formation of HNS{sup −} or HSN{sup −} in their electronic ground states or to autodetachment processes. Thus, providing an explanation for why the anions, SH{sup −}, SN{sup −}, and NH{sup −}, have limiting detectability in astrophysical media despite the observation of their corresponding neutral species. In a biological context, we suggest that HSN{sup −} and HNS{sup −} should be incorporated into H{sub 2}S-assisted heme-catalyzed reduction mechanism of nitrites in vivo.

  3. Model for conductometric detection of carbohydrates and alcohols as complexes with boric acid and borate ion in high-performance liquid chromatography

    International Nuclear Information System (INIS)

    In recent articles, Okada has demonstrated the utility of indirect conductometric detection of electrically neutral sugars and alcohols through their complexes in boric acid solution. The use of a boric acid eluent provides a highly sensitive means of detection for monosaccharides, lactose, and sugar alcohols but not for polysaccharides (other than lactose) and simple alcohols. Addition of sorbitol, mannitol, or fructose to the boric acid eluent allows detection of the polysaccharides and simple alcohols, as well as lactose, glucose, fructose, and presumably other monosaccharides and sugar alcohols. These results were interpreted in terms of the ability of an analyte to form either dissociated or undissociated complexes with boric acid. This interpretation was quantified with a mathematical description of the complexation equilibria and the conductivity due to ionic species. Unfortunately, the mathematical model contains some incorrect assumptions that severely limit the utility of the derived equations and may prevent optimization of this potentially important technique. We present here a more general mathematical model that does not suffer from these limitations

  4. Weak interactions in ion–ligand complexes of C3H3(+) isomers: competition between H-bound and C-bound structures in c-C3H3(+)·L and H2CCCH(+)·L (L = Ne, Ar, N2, CO2, and O2).

    Science.gov (United States)

    Botschwina, Peter; Oswald, Rainer; Dopfer, Otto

    2011-08-21

    Explicitly correlated coupled cluster theory at the CCSD(T)-F12x level (T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys.127, 221106, 2007) has been employed to study structures and vibrations of complexes of type c-C(3)H(3)(+)·L and H(2)C(3)H(+)·L (L = Ne, Ar, N(2), CO(2), and O(2)). Both cations have different binding sites, allowing for the formation of weak to moderately strong hydrogen bonds as well as "C-bound" or "π-bound" structures. In contrast to previous expectations, the energetically most favourable structures of all H(2)C(3)H(+)·L complexes investigated are "C-bound", with the ligand bound to the methylenic carbon atom. The theoretical predictions enable a more detailed interpretation of infrared photodissociation (IRPD) spectra than was possible hitherto. In particular, the bands observed in the range 3238-3245 cm(-1) (D. Roth and O. Dopfer, Phys. Chem. Chem. Phys.4, 4855, 2002) are assigned to essentially free acetylenic CH stretching vibrations of the propargyl cation in "C-bound" H(2)C(3)H(+)·L complexes. PMID:21637871

  5. Role of weakly bound complexes in temperature-dependence and relative rates of MxOy- + H2O (M = Mo, W) reactions

    Science.gov (United States)

    Kafader, Jared O.; Ray, Manisha; Raghavachari, Krishnan; Jarrold, Caroline Chick

    2016-02-01

    Results of a systematic comparison of the MoxOy- + H2O and WxOy- + H2O reaction rate coefficients are reported and compared to previous experimental and computational studies on these reactions. WxOy- clusters undergo more direct oxidation by water to yield WxOy+1- + H2, while for MoxOy- clusters, production of MoxOyH2- (trapped intermediates in the oxidation reaction) is comparatively more prevalent. However, MoxOy- clusters generally have higher rate coefficients than analogous WxOy- clusters if MoxOy+1H2- formation is included. Results of calculations on the M2Oy- + H2O (M = Mo, W; y = 4, 5) reaction entrance channel are reported. They include charge-dipole complexes formed from long-range interactions, and the requisite conversion to a Lewis acid-base complex that leads to MxOy+1H2- formation. The results predict that the Lewis acid-base complex is more strongly bound for MoxOy- clusters than for WxOy- clusters. The calculated free energies along this portion of the reaction path are also consistent with the modest anti-Arrhenius temperature dependence measured for most MoxOy- + H2O reactions, and the WxOy- + H2O reaction rate coefficients generally being constant over the temperature range sampled in this study. For clusters that exhibit evidence of both water addition and oxidation reactions, increasing the temperature increases the branching ratio toward oxidation for both species. A more direct reaction path to H2 production may therefore become accessible at modest temperatures for certain cluster stoichiometries and structures.

  6. Effects of Carbohydrate Consumption Case Study: carbohydrates in Bread

    Directory of Open Access Journals (Sweden)

    Neacsu N.A.

    2014-12-01

    Full Text Available Carbohydrates perform numerous roles in living organisms; they are an important source of energy. The body uses carbohydrates to make glucose which is the fuel that gives it energy and helps keep everything going. However, excess carbohydrate consumption has negative health effects. Bread is a basic product in our nutrition and it also is a product with a high content of carbohydrates. So, it is important to find out more information on bread and on the recommended bread type best for consumption.

  7. Separation and quantification of microalgal carbohydrates.

    Science.gov (United States)

    Templeton, David W; Quinn, Matthew; Van Wychen, Stefanie; Hyman, Deborah; Laurens, Lieve M L

    2012-12-28

    Structural carbohydrates can constitute a large fraction of the dry weight of algal biomass and thus accurate identification and quantification is important for summative mass closure. Two limitations to the accurate characterization of microalgal carbohydrates are the lack of a robust analytical procedure to hydrolyze polymeric carbohydrates to their respective monomers and the subsequent identification and quantification of those monosaccharides. We address the second limitation, chromatographic separation of monosaccharides, here by identifying optimum conditions for the resolution of a synthetic mixture of 13 microalgae-specific monosaccharides, comprised of 8 neutral, 2 amino sugars, 2 uronic acids and 1 alditol (myo-inositol as an internal standard). The synthetic 13-carbohydrate mix showed incomplete resolution across 11 traditional high performance liquid chromatography (HPLC) methods, but showed improved resolution and accurate quantification using anion exchange chromatography (HPAEC) as well as alditol acetate derivatization followed by gas chromatography (for the neutral- and amino-sugars only). We demonstrate the application of monosaccharide quantification using optimized chromatography conditions after sulfuric acid analytical hydrolysis for three model algae strains and compare the quantification and complexity of monosaccharides in analytical hydrolysates relative to a typical terrestrial feedstock, sugarcane bagasse. PMID:23177152

  8. Organizing multivalency in carbohydrate recognition.

    Science.gov (United States)

    Müller, Christian; Despras, Guillaume; Lindhorst, Thisbe K

    2016-06-01

    The interactions of cell surface carbohydrates as well as of soluble glycoconjugates with their receptor proteins rule fundamental processes in cell biology. One of the supramolecular principles underlying and regulating carbohydrate recognition is multivalency. Many multivalent glycoconjugates have therefore been synthesized to study multivalency effects operative in glycobiology. This review is focused on smaller multivalent structures such as glycoclusters emphasizing carbohydrate-centered and heteromultivalent glycoconjugates. We are discussing primary, secondary and tertiary structural aspects including approaches to organize multivalency. PMID:27146554

  9. Cellular delivery of quantum dot-bound hybridization probe for detection of intracellular pre-microRNA using chitosan/poly(γ-glutamic acid complex as a carrier.

    Directory of Open Access Journals (Sweden)

    Yao Geng

    Full Text Available A quantum dot (QD-bound hybridization probe was designed for detection of intracellular pre-miRNA using chitosan (CS/poly(γ-glutamic acid (γ-PGA complex as a gene vector. The probe was prepared by assembling thiolated RNA to gold nanoparticle (Au NP via Au-S bond and then binding 3'-end amine of the RNA to the carboxy group capped on quantum dot surface. The QD-RNA-Au NP probe was assembled on the vector by mixing with aqueous γ-PGA solution and then CS solution to construct a gene delivery system for highly effective cellular uptake and delivery. After the probe was released from CS/γ-PGA complex to the cytoplasm by electrostatic repulsion at intracellular pH, it hybridized with pre-miRNA precursor as target. The formed product was then cleaved by RNase III Dicer, leading to the separation of QDs from Au NPs and fluorescence emission of QDs, which could be detected by confocal microscopic imaging to monitor the amount of the intracellular pre-miRNA precursor. The in vitro assays revealed that the QD-RNA-Au NP was a robust, sensitive and selective probe for quantitative detection of target pre-miRNA. Using MDA-MB231 and MCF-7 breast cancer cells as models, the relative amount of pre-miRNA let-7a could be successfully compared. Since the amount of miRNA is related to the progress and prognosis of cancer, this strategy could be expected to hold promising application potential in medical research and clinical diagnostics.

  10. Cellular delivery of quantum dot-bound hybridization probe for detection of intracellular pre-microRNA using chitosan/poly(γ-glutamic acid) complex as a carrier.

    Science.gov (United States)

    Geng, Yao; Lin, Dajie; Shao, Lijia; Yan, Feng; Ju, Huangxian

    2013-01-01

    A quantum dot (QD)-bound hybridization probe was designed for detection of intracellular pre-miRNA using chitosan (CS)/poly(γ-glutamic acid) (γ-PGA) complex as a gene vector. The probe was prepared by assembling thiolated RNA to gold nanoparticle (Au NP) via Au-S bond and then binding 3'-end amine of the RNA to the carboxy group capped on quantum dot surface. The QD-RNA-Au NP probe was assembled on the vector by mixing with aqueous γ-PGA solution and then CS solution to construct a gene delivery system for highly effective cellular uptake and delivery. After the probe was released from CS/γ-PGA complex to the cytoplasm by electrostatic repulsion at intracellular pH, it hybridized with pre-miRNA precursor as target. The formed product was then cleaved by RNase III Dicer, leading to the separation of QDs from Au NPs and fluorescence emission of QDs, which could be detected by confocal microscopic imaging to monitor the amount of the intracellular pre-miRNA precursor. The in vitro assays revealed that the QD-RNA-Au NP was a robust, sensitive and selective probe for quantitative detection of target pre-miRNA. Using MDA-MB231 and MCF-7 breast cancer cells as models, the relative amount of pre-miRNA let-7a could be successfully compared. Since the amount of miRNA is related to the progress and prognosis of cancer, this strategy could be expected to hold promising application potential in medical research and clinical diagnostics. PMID:23762388

  11. The binding of platinum hexahalides (Cl, Br and I) to hen egg-white lysozyme and the chemical transformation of the PtI6 octahedral complex to a PtI3 moiety bound to His15

    International Nuclear Information System (INIS)

    The platinum hexahalides have an octahedral arrangement of six halogen atoms bound to a Pt centre, thus having an octahedral shape that could prove to be useful in interpreting poor electron-density maps. In a detailed characterization, PtI6 chemically transformed to a square-planar PtI3 complex bound to the Nδ atom of His15 of HEWL was also observed, which was not observed for PtBr6 or PtCl6. This study examines the binding and chemical stability of the platinum hexahalides K2PtCl6, K2PtBr6 and K2PtI6 when soaked into pre-grown hen egg-white lysozyme (HEWL) crystals as the protein host. Direct comparison of the iodo complex with the chloro and bromo complexes shows that the iodo complex is partly chemically transformed to a square-planar PtI3 complex bound to the Nδ atom of His15, a chemical behaviour that is not exhibited by the chloro or bromo complexes. Each complex does, however, bind to HEWL in its octahedral form either at one site (PtI6) or at two sites (PtBr6 and PtCl6). As heavy-atom derivatives of a protein, the octahedral shape of the hexahalides could be helpful in cases of difficult-to-interpret electron-density maps as they would be recognisable ‘objects’

  12. Detection of gear cracks in a complex gearbox of wind turbines using supervised bounded component analysis of vibration signals collected from multi-channel sensors

    Science.gov (United States)

    Li, Zhixiong; Yan, Xinping; Wang, Xuping; Peng, Zhongxiao

    2016-06-01

    In the complex gear transmission systems, in wind turbines a crack is one of the most common failure modes and can be fatal to the wind turbine power systems. A single sensor may suffer with issues relating to its installation position and direction, resulting in the collection of weak dynamic responses of the cracked gear. A multi-channel sensor system is hence applied in the signal acquisition and the blind source separation (BSS) technologies are employed to optimally process the information collected from multiple sensors. However, literature review finds that most of the BSS based fault detectors did not address the dependence/correlation between different moving components in the gear systems; particularly, the popular used independent component analysis (ICA) assumes mutual independence of different vibration sources. The fault detection performance may be significantly influenced by the dependence/correlation between vibration sources. In order to address this issue, this paper presents a new method based on the supervised order tracking bounded component analysis (SOTBCA) for gear crack detection in wind turbines. The bounded component analysis (BCA) is a state of art technology for dependent source separation and is applied limitedly to communication signals. To make it applicable for vibration analysis, in this work, the order tracking has been appropriately incorporated into the BCA framework to eliminate the noise and disturbance signal components. Then an autoregressive (AR) model built with prior knowledge about the crack fault is employed to supervise the reconstruction of the crack vibration source signature. The SOTBCA only outputs one source signal that has the closest distance with the AR model. Owing to the dependence tolerance ability of the BCA framework, interfering vibration sources that are dependent/correlated with the crack vibration source could be recognized by the SOTBCA, and hence, only useful fault information could be preserved in

  13. Impact of Dietary Carbohydrate and Protein Levels on Carbohydrate Metabolism

    Science.gov (United States)

    Lasker, Denise Ann

    2009-01-01

    The goal of this dissertation was to investigate the impact of changing dietary carbohydrate (CARB) intakes within recommended dietary guidelines on metabolic outcomes specifically associated with glycemic regulations and carbohydrate metabolism. This research utilized both human and animal studies to examine changes in metabolism across a wide…

  14. Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria

    Directory of Open Access Journals (Sweden)

    Muscariello Lidia

    2006-05-01

    D proteins form cell-surface protein complexes and play a role in carbon source acquisition. Primary occurrence in plant-associated gram-positive bacteria suggests a possible role in degradation and utilization of plant oligo- or poly-saccharides.

  15. The Carbohydrate-linked Phosphorylcholine of the Parasitic Nematode Product ES-62 Modulates Complement Activation.

    Science.gov (United States)

    Ahmed, Umul Kulthum; Maller, N Claire; Iqbal, Asif J; Al-Riyami, Lamyaa; Harnett, William; Raynes, John G

    2016-05-27

    Parasitic nematodes manufacture various carbohydrate-linked phosphorylcholine (PCh)-containing molecules, including ES-62, a protein with an N-linked glycan terminally substituted with PCh. The PCh component is biologically important because it is required for immunomodulatory effects. We showed that most ES-62 was bound to a single protein, C-reactive protein (CRP), in normal human serum, displaying a calcium-dependent, high-avidity interaction and ability to form large complexes. Unexpectedly, CRP binding to ES-62 failed to efficiently activate complement as far as the C3 convertase stage in comparison with PCh-BSA and PCh-containing Streptococcus pneumoniae cell wall polysaccharide. C1q capture assays demonstrated an ES-62-CRP-C1q interaction in serum. The three ligands all activated C1 and generated C4b to similar extents. However, a C2a active site was not generated following ES-62 binding to CRP, demonstrating that C2 cleavage was far less efficient for ES-62-containing complexes. We proposed that failure of C2 cleavage was due to the flexible nature of carbohydrate-bound PCh and that reduced proximity of the C1 complex was the reason that C2 was poorly cleaved. This was confirmed using synthetic analogues that were similar to ES-62 only in respect of having a flexible PCh. Furthermore, ES-62 was shown to deplete early complement components, such as the rate-limiting C4, following CRP interaction and thereby inhibit classical pathway activation. Thus, flexible PCh-glycan represents a novel mechanism for subversion of complement activation. These data illustrate the importance of the rate-limiting C4/C2 stage of complement activation and reveal a new addition to the repertoire of ES-62 immunomodulatory mechanisms with possible therapeutic applications. PMID:27044740

  16. Carbohydrates and Diabetes (For Parents)

    Science.gov (United States)

    ... of diet foods. These foods may contain extra sugar as a substitute for fat calories. Try to include your child or teen as you evaluate and select healthy carbohydrate-containing foods. With ... blood sugar. By taking a smart approach to balancing carbohydrates, ...

  17. Bounded Rationality

    Directory of Open Access Journals (Sweden)

    Ballester Pla, Coralio

    2012-03-01

    Full Text Available The observation of the actual behavior by economic decision makers in the lab and in the field justifies that bounded rationality has been a generally accepted assumption in many socio-economic models. The goal of this paper is to illustrate the difficulties involved in providing a correct definition of what a rational (or irrational agent is. In this paper we describe two frameworks that employ different approaches for analyzing bounded rationality. The first is a spatial segregation set-up that encompasses two optimization methodologies: backward induction and forward induction. The main result is that, even under the same state of knowledge, rational and non-rational agents may match their actions. The second framework elaborates on the relationship between irrationality and informational restrictions. We use the beauty contest (Nagel, 1995 as a device to explain this relationship.

    La observación del comportamiento de los agentes económicos tanto en el laboratorio como en la vida real justifica que la racionalidad acotada sea un supuesto aceptado en numerosos modelos socio-económicos. El objetivo de este artículo es ilustrar las dificultades que conlleva una correcta definición de qué es un agente racional (irracional. En este artículo se describen dos marcos que emplean diferentes metodologías para analizar la racionalidad acotada. El primero es un modelo de segregación espacial donde se contrastan dos metodologías de optimización: inducción hacia atrás y hacia adelante. El resultado principal es que, incluso con el mismo nivel de conocimiento, tanto agentes racionales como irracionales podrían coincidir en sus acciones. El segundo marco trabaja sobre la relación entre irracionalidad y restricción de información. Se utiliza el juego llamado “beauty contest” (Nagel 1995 como mecanismo para explicar dicha relación.

  18. Correlation between carbohydrate structures on the envelope glycoprotein gp120 of HIV-1 and HIV-2 and syncytium inhibition with lectins

    DEFF Research Database (Denmark)

    Hansen, J E; Nielsen, C M; Nielsen, C;

    1989-01-01

    The binding of 13 different lectins to gp120 partially purified from two HIV-1 isolates and one HIV-2 isolate was studied by in situ staining on electrophoretically separated and electroblotted HIV antigens. The lectins concanavalin A, wheat germ agglutinin, Lens culinaris agglutinin, Vicia faba...... agglutinin, Pisum sativum agglutinin and phytohaem(erythro)agglutinin bound to gp120 of all three isolates. The carbohydrate of gp120 recognized by lectins was thus arranged in at least four types of glycans: a high mannose type glycan, a bisected hybrid or complex type glycan, a biantennary fucosylated...

  19. The binding of platinum hexahalides (Cl, Br and I) to hen egg-white lysozyme and the chemical transformation of the PtI{sub 6} octahedral complex to a PtI{sub 3} moiety bound to His15

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M.; Starkey, Laurina-Victoria; Lamplough, Lucinda; Kaenket, Surasek; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

    2014-08-29

    The platinum hexahalides have an octahedral arrangement of six halogen atoms bound to a Pt centre, thus having an octahedral shape that could prove to be useful in interpreting poor electron-density maps. In a detailed characterization, PtI{sub 6} chemically transformed to a square-planar PtI{sub 3} complex bound to the N{sup δ} atom of His15 of HEWL was also observed, which was not observed for PtBr{sub 6} or PtCl{sub 6}. This study examines the binding and chemical stability of the platinum hexahalides K{sub 2}PtCl{sub 6}, K{sub 2}PtBr{sub 6} and K{sub 2}PtI{sub 6} when soaked into pre-grown hen egg-white lysozyme (HEWL) crystals as the protein host. Direct comparison of the iodo complex with the chloro and bromo complexes shows that the iodo complex is partly chemically transformed to a square-planar PtI{sub 3} complex bound to the N{sup δ} atom of His15, a chemical behaviour that is not exhibited by the chloro or bromo complexes. Each complex does, however, bind to HEWL in its octahedral form either at one site (PtI{sub 6}) or at two sites (PtBr{sub 6} and PtCl{sub 6}). As heavy-atom derivatives of a protein, the octahedral shape of the hexahalides could be helpful in cases of difficult-to-interpret electron-density maps as they would be recognisable ‘objects’.

  20. Transition metals in carbohydrate chemistry

    DEFF Research Database (Denmark)

    Madsen, Robert

    1997-01-01

    This review describes the application of transition metal mediated reactions in carbohydrate synthesis. The different metal mediated transformations are divided into reaction types and illustrated by various examples on monosaccharide derivatives. Carbon-carbon bond forming reactions are further ...

  1. Carbohydrates, Sugar, and Your Child

    Science.gov (United States)

    ... are: simple carbohydrates (or simple sugars): these include fructose, glucose, and lactose, which also are found in nutritious ... look at the ingredient list for sugar, corn syrup or sweetener, dextrose, fructose, honey, or molasses, to name just a few. ...

  2. Galacturonosyltransferase (GAUT)1 and GAUT7 are the core of a plant cell wall pectin biosynthetic homogalacturonan:galacturonosyltransferase complex

    OpenAIRE

    Atmodjo, Melani A.; Sakuragi, Yumiko; Zhu, Xiang; Burrell, Amy J.; Mohanty, Sushree S; Atwood, James A.; Orlando, Ron; Henrik V. Scheller; Mohnen, Debra

    2011-01-01

    Plant cell wall pectic polysaccharides are arguably the most complex carbohydrates in nature. Progress in understanding pectin synthesis has been slow due to its complex structure and difficulties in purifying and expressing the low-abundance, Golgi membrane-bound pectin biosynthetic enzymes. Arabidopsis galacturonosyltransferase (GAUT) 1 is an α-1,4-galacturonosyltransferase (GalAT) that synthesizes homogalacturonan (HG), the most abundant pectic polysaccharide. We now show that GAUT1 functi...

  3. Method Optimization for Rapid Measurement of Carbohydrates in Plasma by Liquid Chromatography Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ductoan; Yu, Jondong; Mho, Sunil; Lee, Gwang [Ajou Univ., Suwon (Korea, Republic of); Lee, Haelee; Paik, Manjeong [Sangdosijang Pharmacy, Seoul (Korea, Republic of); Yee, Sungtae [Sunchon National Univ., Suncheon (Korea, Republic of)

    2013-05-15

    In conclusion, the developed HPLC coupled with ESI-MS was a powerful technique for the separation and characterization of carbohydrates by either SIM or MRM mode. The present method will be useful for the monitoring of carbohydrate profile in biological fluids from various diseases including diabetic ketoacidosis, hypoglycemia and hyperosmolar coma. Carbohydrates are one of the most abundant classes of organic compounds in nature, which not only constitute complex biomolecules in human and animals but are also distributed in plants and bacteria.

  4. 多糖存在下异丁香酚的脱氢聚合及LCC的形成%Dehydrogenation Polymerization of Isoeugenol and Formation of Lignin-carbohydrate Complexes with Presence of Polysaccharide

    Institute of Scientific and Technical Information of China (English)

    叶哲孜; 谢益民; 吴晨曦; 王鹏; 乐喜

    2016-01-01

    Dehydrogenation polymer ( DHP ) and lignin-carbohydrate complexes ( LCC ) were prepared using isoeugenol as precursor of lignin biosynthesis by mixing method. The chemical structure of the polymers was analyzed with Fourier transform infrared spectroscopy ( FT-IR ) and 13C NMR spectroscopy. The dehydrogenation polymerization reaction between DHP and polysaccharide ( arabinogalactan) using the laccase as catalyst was investigated. The results showed that isoeugenol could be polymerized with arabinogalactan to form DHP and LCC catalyzed by laccase. The analysis of the 13C NMR spectra also indicated that the DHP was mainly composed ofβ-O-4,β-β,β-5 andβ-1 subunits. The information from the aromatic carbons of lignin and resonance signals of the arabinogalactan could be found in the 13C NMR spectrum of the LCC.%以异丁香酚为木质素生物合成的前驱物,采用混合法合成了木质素脱氢聚合物( DHP)和木质素-碳水化合物复合体( LCC),同时采用红外光谱、13C NMR波谱分析聚合产物的结构,探讨了漆酶催化脱氢聚合过程中形成的DHP与多糖(阿拉伯半乳聚糖)的聚合反应机理。结果表明:在漆酶的催化作用下,异丁香酚与阿拉伯半乳聚糖发生聚合形成了DHP与LCC,13C NMR波谱结果证实DHP中以β-O-4,β-β,β-5和β-1等结构为主,而LCC的13C NMR谱图中既有来自木质素的芳香族碳原子的信息,也有来自阿拉伯半乳聚糖的共振信号。

  5. Family 42 carbohydrate-binding modules display multiple arabinoxylan-binding interfaces presenting different ligand affinities.

    Science.gov (United States)

    Ribeiro, Teresa; Santos-Silva, Teresa; Alves, Victor D; Dias, Fernando M V; Luís, Ana S; Prates, José A M; Ferreira, Luís M A; Romão, Maria J; Fontes, Carlos M G A

    2010-10-01

    Enzymes that degrade plant cell wall polysaccharides display a modular architecture comprising a catalytic domain bound to one or more non-catalytic carbohydrate-binding modules (CBMs). CBMs display considerable variation in primary structure and are grouped into 59 sequence-based families organized in the Carbohydrate-Active enZYme (CAZy) database. Here we report the crystal structure of CtCBM42A together with the biochemical characterization of two other members of family 42 CBMs from Clostridium thermocellum. CtCBM42A, CtCBM42B and CtCBM42C bind specifically to the arabinose side-chains of arabinoxylans and arabinan, suggesting that various cellulosomal components are targeted to these regions of the plant cell wall. The structure of CtCBM42A displays a beta-trefoil fold, which comprises 3 sub-domains designated as alpha, beta and gamma. Each one of the three sub-domains presents a putative carbohydrate-binding pocket where an aspartate residue located in a central position dominates ligand recognition. Intriguingly, the gamma sub-domain of CtCBM42A is pivotal for arabinoxylan binding, while the concerted action of beta and gamma sub-domains of CtCBM42B and CtCBM42C is apparently required for ligand sequestration. Thus, this work reveals that the binding mechanism of CBM42 members is in contrast with that of homologous CBM13s where recognition of complex polysaccharides results from the cooperative action of three protein sub-domains presenting similar affinities. PMID:20637315

  6. Structural basis of carbohydrate recognition by a Man(alpha1-2)Man-specific lectin from Bowringia milbraedii.

    Science.gov (United States)

    Buts, Lieven; Garcia-Pino, Abel; Wyns, Lode; Loris, Remy

    2006-07-01

    The crystal structure of the seed lectin from the tropical legume Bowringia milbraedii was determined in complex with the disaccharide ligand Man(alpha1-2)Man. In solution, the protein exhibits a dynamic dimer-tetramer equilibrium, consistent with the concanavalin A-type tetramer observed in the crystal. Contacts between the tetramers are mediated almost exclusively through the carbohydrate ligand, resulting in a crystal lattice virtually identical to that of the concanavalin-A:Man(alpha1-2)Man complex, even though both proteins have less than 50% sequence identity. The disaccharide binds exclusively in a "downstream" binding mode, with the non-reducing mannose occupying the monosaccharide-binding site. The reducing mannose is bound in a predominantly polar subsite involving Tyr131, Gln218, and Tyr219. PMID:16567368

  7. Polynomially Bounded Sequences and Polynomial Sequences

    Directory of Open Access Journals (Sweden)

    Okazaki Hiroyuki

    2015-09-01

    Full Text Available In this article, we formalize polynomially bounded sequences that plays an important role in computational complexity theory. Class P is a fundamental computational complexity class that contains all polynomial-time decision problems [11], [12]. It takes polynomially bounded amount of computation time to solve polynomial-time decision problems by the deterministic Turing machine. Moreover we formalize polynomial sequences [5].

  8. Carbohydrates Through Animation: Preliminary Step

    Directory of Open Access Journals (Sweden)

    J.K. Sugai

    2004-05-01

    Full Text Available Methods of education are changing, so the educational tools must change too. The developmentof the systems of information and communication gave the opportunity to bring new technology tothe learning process. Modern education needs interactive programs that may be available to theacademic community, in order to ease the learning process and sharing of the knowledge. Then,an educational software on Carbohydrates is being developed using concept maps and FLASH-MXanimations program, and approached through six modules. The introduction of Carbohydrates wasmade by the module Carbohydrates on Nature, which shows the animations gures of a teacher andstudents, visiting a farm, identifying the carbohydrates found in vegetables, animals, and microor-ganisms, integrated by links containing short texts to help understanding the structure and functionof carbohydrates. This module was presented, as pilot experiment, to teachers and students, whichdemonstrated satisfaction, and high receptivity, by using animation and interactivitys program asstrategy to biochemistrys education. The present work is part of the project Biochemistry throughanimation, which is having continuity.

  9. STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A BIDENTATE POLYMER BOUND CIS-DICARBONYLRHODIUM COMPLEX AS CATALYST

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaojun; LIU Zhongyang; PAN Pinglai; YUAN Guoqing

    1996-01-01

    Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.

  10. Protective group strategies in carbohydrate and peptide chemistry

    NARCIS (Netherlands)

    Ali, Asghar

    2010-01-01

    Protecting groups play a key role in the synthesis of complex natural products.This holds especially true for the synthesis of oligosaccharides, of which the monomeric carbohydrate building blocks usually contain up to five different hydroxyl functions. The discrimination of these hydroxyl functions

  11. Advancing Analytical Methods for Characterization of Anionic Carbohydrate Biopolymers

    OpenAIRE

    Langeslay, Derek Joseph

    2013-01-01

    The focus of this dissertation is on the development of improved analytical methods for the characterization of anionic carbohydrate biopolymers. Our goal is to extract important information from complex mixtures of heterogeneous polysaccharides by characterizing their substituent oligosaccharides in terms of monosaccharide composition and primary and secondary structure. This work focuses on the application of two major analytical platforms: spectroscopy and chromatography. The development ...

  12. Bounded generalized Harish-Chandra modules

    OpenAIRE

    Penkov, Ivan; Serganova, Vera

    2007-01-01

    Let $\\gg$ be a complex reductive Lie algebra and $\\kk\\subset\\gg$ be any reductive in $\\gg$ subalgebra. We call a $(\\gg,\\kk)$-module $M$ bounded if the $\\kk$-multiplicities of $M$ are uniformly bounded. In this paper we initiate a general study of simple bounded $(\\gg,\\kk)$-modules. We prove a strong necessary condition for a subalgebra $\\kk$ to be bounded (Corollary \\ref{cor1.6}), i.e. to admit an infinite-dimensional simple bounded $(\\gg,\\kk)$-module, and then establish a sufficient conditio...

  13. Carbohydrates of human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, J E

    1992-01-01

    Elucidation of the mechanism by which viral infection induces the appearance of carbohydrate neoantigens is highly important. Results from such studies could be expected to be significant for a general understanding of the regulation of glycosylation, and perhaps especially important for the unde...

  14. Biophysical insights into the intercalative interaction of surfactant cobalt(III) complexes of certain diimine ligands bound to yeast tRNA: Effects of hydrophobicity

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2015-08-01

    The interaction of two surfactant cobalt(III) complexes, cis-[Co(ip)2(DA)2](ClO4)3 1 and cis-[Co(dpq)2(DA)2](ClO4)3 2 where ip = imidazo[4,5-f][1,10]phenanthroline and dpq = dipyrido[3,2-d:2‧-3‧-f]quinoxaline with yeast tRNA have been explored by using electronic absorption, competitive binding, electrochemical studies and viscosity measurements. The results suggest that these complexes can bind to tRNA by intercalation. The presence of hydrophobic diimine ligand and the long aliphatic double chains of these complexes facilitate its intercalative interaction with the hydrophobic interior of the tRNA. The extent of tRNA binding of complex 2 has greater affinity than that of complex containing imidazo[4,5-f][1,10]phenanthroline ligands.

  15. Carbohydrate-Related Inhibitors of Dengue Virus Entry

    Directory of Open Access Journals (Sweden)

    Takashi Suzuki

    2013-02-01

    Full Text Available Dengue virus (DENV, which is transmitted by Aedes mosquitoes, causes fever and hemorrhagic disorders in humans. The virus entry process mediated through host receptor molecule(s is crucial for virus propagation and the pathological progression of dengue disease. Therefore, elucidation of the molecular mechanisms underlying virus entry is essential for an understanding of dengue pathology and for the development of effective new anti-dengue agents. DENV binds to its receptor molecules mediated through a viral envelope (E protein, followed by incorporation of the virus-receptor complex inside cells. The fusion between incorporated virus particles and host endosome membrane under acidic conditions is mediated through the function of DENV E protein. Carbohydrate molecules, such as sulfated glycosaminoglycans (GAG and glycosphingolipids, and carbohydrate-recognition proteins, termed lectins, inhibit virus entry. This review focuses on carbohydrate-derived entry inhibitors, and also introduces functionally related compounds with similar inhibitory mechanisms against DENV entry.

  16. Carbohydrates - Multiple Languages: MedlinePlus

    Science.gov (United States)

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Carbohydrates URL of this page: https://medlineplus.gov/languages/carbohydrates.html Other topics A-Z A B ...

  17. Vina-Carb: Improving Glycosidic Angles during Carbohydrate Docking.

    Science.gov (United States)

    Nivedha, Anita K; Thieker, David F; Makeneni, Spandana; Hu, Huimin; Woods, Robert J

    2016-02-01

    Molecular docking programs are primarily designed to align rigid, drug-like fragments into the binding sites of macromolecules and frequently display poor performance when applied to flexible carbohydrate molecules. A critical source of flexibility within an oligosaccharide is the glycosidic linkages. Recently, Carbohydrate Intrinsic (CHI) energy functions were reported that attempt to quantify the glycosidic torsion angle preferences. In the present work, the CHI-energy functions have been incorporated into the AutoDock Vina (ADV) scoring function, subsequently termed Vina-Carb (VC). Two user-adjustable parameters have been introduced, namely, a CHI- energy weight term (chi_coeff) that affects the magnitude of the CHI-energy penalty and a CHI-cutoff term (chi_cutoff) that negates CHI-energy penalties below a specified value. A data set consisting of 101 protein-carbohydrate complexes and 29 apoprotein structures was used in the development and testing of VC, including antibodies, lectins, and carbohydrate binding modules. Accounting for the intramolecular energies of the glycosidic linkages in the oligosaccharides during docking led VC to produce acceptable structures within the top five ranked poses in 74% of the systems tested, compared to a success rate of 55% for ADV. An enzyme system was employed in order to illustrate the potential application of VC to proteins that may distort glycosidic linkages of carbohydrate ligands upon binding. VC represents a significant step toward accurately predicting the structures of protein-carbohydrate complexes. Furthermore, the described approach is conceptually applicable to any class of ligands that populate well-defined conformational states. PMID:26744922

  18. Computational glycoscience: characterizing the spatial and temporal properties of glycans and glycan-protein complexes.

    Science.gov (United States)

    Woods, Robert J; Tessier, Matthew B

    2010-10-01

    Modern computational methods offer the tools to provide insight into the structural and dynamic properties of carbohydrate-protein complexes, beyond that provided by experimental structural biology. Dynamic properties such as the fluctuation of inter-molecular hydrogen bonds, the residency times of bound water molecules, side chain motions and ligand flexibility may be readily determined computationally. When taken with respect to the unliganded states, these calculations can also provide insight into the entropic and enthalpic changes in free energy associated with glycan binding. In addition, virtual ligand screening may be employed to predict the three dimensional (3D) structures of carbohydrate-protein complexes, given 3D structures for the components. In principle, the 3D structure of the protein may itself be derived by modeling, leading to the exciting--albeit high risk--realm of virtual structure prediction. This latter approach is appealing, given the difficulties associated with generating experimental 3D structures for some classes of glycan binding proteins; however, it is also the least robust. An unexpected outcome of the development of algorithms for modeling carbohydrate-protein interactions has been the discovery of errors in reported experimental 3D structures and a heightened awareness of the need for carbohydrate-specific computational tools for assisting in the refinement and curation of carbohydrate-containing crystal structures. Here we present a summary of the basic strategies associated with employing classical force field based modeling approaches to problems in glycoscience, with a focus on identifying typical pitfalls and limitations. This is not an exhaustive review of the current literature, but hopefully will provide a guide for the glycoscientist interested in modeling carbohydrates and carbohydrate-protein complexes, as well as the computational chemist contemplating such tasks. PMID:20708922

  19. Entirely Carbohydrate-Based Vaccines: An Emerging Field for Specific and Selective Immune Responses

    Science.gov (United States)

    Nishat, Sharmeen; Andreana, Peter R.

    2016-01-01

    Carbohydrates are regarded as promising targets for vaccine development against infectious disease because cell surface glycans on many infectious agents are attributed to playing an important role in pathogenesis. In addition, oncogenic transformation of normal cells, in many cases, is associated with aberrant glycosylation of the cell surface glycan generating tumor associated carbohydrate antigens (TACAs). Technological advances in glycobiology have added a new dimension to immunotherapy when considering carbohydrates as key targets in developing safe and effective vaccines to combat cancer, bacterial infections, viral infections, etc. Many consider effective vaccines induce T-cell dependent immunity with satisfactory levels of immunological memory that preclude recurrence. Unfortunately, carbohydrates alone are poorly immunogenic as they do not bind strongly to the MHCII complex and thus fail to elicit T-cell immunity. To increase immunogenicity, carbohydrates have been conjugated to carrier proteins, which sometimes can impede carbohydrate specific immunity as peptide-based immune responses can negate antibodies directed at the targeted carbohydrate antigens. To overcome many challenges in using carbohydrate-based vaccine design and development approaches targeting cancer and other diseases, zwitterionic polysaccharides (ZPSs), isolated from the capsule of commensal anaerobic bacteria, will be discussed as promising carriers of carbohydrate antigens to achieve desired immunological responses. PMID:27213458

  20. Entirely Carbohydrate-Based Vaccines: An Emerging Field for Specific and Selective Immune Responses.

    Science.gov (United States)

    Nishat, Sharmeen; Andreana, Peter R

    2016-01-01

    Carbohydrates are regarded as promising targets for vaccine development against infectious disease because cell surface glycans on many infectious agents are attributed to playing an important role in pathogenesis. In addition, oncogenic transformation of normal cells, in many cases, is associated with aberrant glycosylation of the cell surface glycan generating tumor associated carbohydrate antigens (TACAs). Technological advances in glycobiology have added a new dimension to immunotherapy when considering carbohydrates as key targets in developing safe and effective vaccines to combat cancer, bacterial infections, viral infections, etc. Many consider effective vaccines induce T-cell dependent immunity with satisfactory levels of immunological memory that preclude recurrence. Unfortunately, carbohydrates alone are poorly immunogenic as they do not bind strongly to the MHCII complex and thus fail to elicit T-cell immunity. To increase immunogenicity, carbohydrates have been conjugated to carrier proteins, which sometimes can impede carbohydrate specific immunity as peptide-based immune responses can negate antibodies directed at the targeted carbohydrate antigens. To overcome many challenges in using carbohydrate-based vaccine design and development approaches targeting cancer and other diseases, zwitterionic polysaccharides (ZPSs), isolated from the capsule of commensal anaerobic bacteria, will be discussed as promising carriers of carbohydrate antigens to achieve desired immunological responses. PMID:27213458

  1. Circuit lower bounds in bounded arithmetics

    Czech Academy of Sciences Publication Activity Database

    Pich, Ján

    2015-01-01

    Roč. 166, č. 1 (2015), s. 29-45. ISSN 0168-0072 R&D Projects: GA AV ČR IAA100190902 Keywords : bounded arithmetic * circuit lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.548, year: 2014 http://www.sciencedirect.com/science/article/pii/S0168007214000888

  2. Capacity Bounds for Parallel Optical Wireless Channels

    KAUST Repository

    Chaaban, Anas

    2016-01-01

    A system consisting of parallel optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. Under perfect channel-state information at the transmitter (CSIT), the bounds have to be optimized with respect to the power allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the KKT conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose low-complexity power allocation algorithms which are nearly optimal. The optimized capacity lower bound nearly coincides with the capacity at high SNR. Without CSIT, our capacity bounds lead to upper and lower bounds on the outage probability. The outage probability bounds meet at high SNR. The system with average and peak intensity constraints is also discussed.

  3. Fluorous-based carbohydrate quartz crystal microbalance.

    Science.gov (United States)

    Chen, Lei; Sun, Pengfei; Chen, Guosong

    2015-03-20

    Fluorous chemistry has brought many applications from catalysis to separation science, from supramolecular materials to analytical chemistry. However, fluorous-based quartz crystal microbalance (QCM) has not been reported so far. In the current paper, fluorous interaction has been firstly utilized in QCM, and carbohydrate-protein interaction and carbohydrate-carbohydrate interaction have been detected afterward. PMID:25541017

  4. Interactions of carbohydrates and proteins by fluorophore-assisted carbohydrate electrophoresis

    Indian Academy of Sciences (India)

    Gang-Liang Huang; Xin-Ya Mei; Peng-George Wang

    2006-06-01

    A sensitive, specific, and rapid method for the detection of carbohydrate-protein interactions is demonstrated by fluorophore-assisted carbohydrate electrophoresis (FACE). The procedure is simple and the cost is low. The advantage of this method is that carbohydrate-protein interactions can be easily displayed by FACE, and the carbohydrates do not need to be purified.

  5. A single-molecule force spectroscopy study of the interactions between lectins and carbohydrates on cancer and normal cells

    Science.gov (United States)

    Zhao, Weidong; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Wang, Hongda

    2013-03-01

    The interaction forces between carbohydrates and lectins were investigated by single-molecule force spectroscopy on both cancer and normal cells. The binding kinetics was also studied, which shows that the carbohydrate-lectin complex on cancer cells is less stable than that on normal cells.The interaction forces between carbohydrates and lectins were investigated by single-molecule force spectroscopy on both cancer and normal cells. The binding kinetics was also studied, which shows that the carbohydrate-lectin complex on cancer cells is less stable than that on normal cells. Electronic supplementary information (ESI) available: Experimental details. See DOI: 10.1039/c3nr00553d

  6. A Causal Entropy Bound

    CERN Document Server

    Brustein, Ram

    2000-01-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic space-like region. This "causal entropy bound", scaling as the square root of EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various "critical" situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso's holographic bound are stronger than Bekenstein's, while naive holography is too tight, and hence typically wrong.

  7. Carbohydrate Microarrays in Plant Science

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik; Pedersen, H.L.; Vidal-Melgosa, S.;

    2012-01-01

    Almost all plant cells are surrounded by glycan-rich cell walls, which form much of the plant body and collectively are the largest source of biomass on earth. Plants use polysaccharides for support, defense, signaling, cell adhesion, and as energy storage, and many plant glycans are also important...... industrially and nutritionally. Understanding the biological roles of plant glycans and the effective exploitation of their useful properties requires a detailed understanding of their structures, occurrence, and molecular interactions. Microarray technology has revolutionized the massively high...... plant research and can be used to map glycan populations across large numbers of samples to screen antibodies, carbohydrate binding proteins, and carbohydrate binding modules and to investigate enzyme activities....

  8. Quantum Lower Bounds by Entropy Numbers

    OpenAIRE

    Heinrich, Stefan

    2006-01-01

    We use entropy numbers in combination with the polynomial method to derive a new general lower bound for the n-th minimal error in the quantum setting of information-based complexity. As an application, we improve some lower bounds on quantum approximation of embeddings between finite dimensional L_p spaces and of Sobolev embeddings.

  9. On the range of completely bounded maps

    Directory of Open Access Journals (Sweden)

    Richard I. Loebl

    1978-01-01

    Full Text Available It is shown that if every bounded linear map from a C*-algebra α to a von Neumann algebra β is completely bounded, then either α is finite-dimensional or β⫅⊗Mn, where is a commutative von Neumann algebra and Mn is the algebra of n×n complex matrices.

  10. Carbohydrates Through Animation: Preliminary Step

    OpenAIRE

    J.K. Sugai; M.S.R. Figueiredo; R.V. Antônio; P.M Oliveira; V.A Cardoso; Ricardo, J.; Merino, E; Figueiredo, L. F.; D.N. Heidrich

    2004-01-01

    Methods of education are changing, so the educational tools must change too. The developmentof the systems of information and communication gave the opportunity to bring new technology tothe learning process. Modern education needs interactive programs that may be available to theacademic community, in order to ease the learning process and sharing of the knowledge. Then,an educational software on Carbohydrates is being developed using concept maps and FLASH-MXanimations program, and approach...

  11. Improved Range Searching Lower Bounds

    DEFF Research Database (Denmark)

    Larsen, Kasper Green; Nguyen, Huy L.

    2012-01-01

    range reporting problem. In approximate simplex range reporting, points that lie within a distance of ε ⋅ Diam(s) from the border of a query simplex s, are free to be included or excluded from the output, where ε ≥ 0 is an input parameter to the range searching problem. We prove our lower bounds......Table of Contents -------------------------------------------------------------------------------- In this paper we present a number of improved lower bounds for range searching in the pointer machine and the group model. In the pointer machine, we prove lower bounds for the approximate simplex...... by constructing a hard input set and query set, and then invoking Chazelle and Rosenberg's [CGTA'96] general theorem on the complexity of navigation in the pointer machine. For the group model, we show that input sets and query sets that are hard for range reporting in the pointer machine (i.e. by Chazelle...

  12. Scattering by bound nucleons

    International Nuclear Information System (INIS)

    Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)

  13. Variance bounding Markov chains

    OpenAIRE

    Roberts, Gareth O.; Jeffrey S. Rosenthal

    2008-01-01

    We introduce a new property of Markov chains, called variance bounding. We prove that, for reversible chains at least, variance bounding is weaker than, but closely related to, geometric ergodicity. Furthermore, variance bounding is equivalent to the existence of usual central limit theorems for all L2 functionals. Also, variance bounding (unlike geometric ergodicity) is preserved under the Peskun order. We close with some applications to Metropolis–Hastings algorithms.

  14. Bound states and the Bekenstein bound

    CERN Document Server

    Bousso, R

    2004-01-01

    We explore the validity of the generalized Bekenstein bound, S <= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width a. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.

  15. Survival and changes in the fine structure of selected tissues of Penaeus monodon Fabricius juveniles fed various carbohydrates

    OpenAIRE

    Pascual, F.P.; Coloso, R.M.; Tamse, C.T.

    1981-01-01

    Penaeus monodon juveniles were reared on semipurified diets containing various carbohydrates (maltose, sucrose, dextrin, molasses, cassava starch, corn starch or sago palm starch). Significant differences were observed between the type as well as the level of carbohydrate in the diet on the survival of the juveniles. Results indicate that there does not seem to be any correlation between survival and the complexity of the carbohydrates.

  16. Broadband Microwave Spectroscopy as a Tool to Study the Structures of Odorant Molecules and Weakly Bound Complexes in the Gas Phase

    Science.gov (United States)

    Zinn, Sabrina; Betz, Thomas; Medcraft, Chris; Schnell, Melanie

    2015-06-01

    The rotational spectrum of trans-cinnamaldehyde ((2E)-3-phenylprop-2-enal) has been obtained with chirped-pulse microwave spectroscopy in the frequency range of 2 - 8.5 GHz. The odorant molecule is the essential component in cinnamon oil and causes the characteristic smell. In the measured high-resolution spectrum, we were able to assign the rotational spectra of two conformers of trans-cinnamaldehyde as well as all singly 13C-substituted species of the lowest-energy conformer in natural abundance. Two different methods were used to determine the structure from the rotational constants, which will be compared within this contribution. In addition, the current progress of studying ether-alcohol complexes, aiming at an improved understanding of the interplay between hydrogen bonding and dispersion interaction, will be reported. Here, a special focus is placed on the complexes of diphenylether with small aliphatic alcohols.

  17. Purification of a NifEN protein complex that contains bound molybdenum and a FeMo-Co precursor from an Azotobacter vinelandii DeltanifHDK strain.

    Science.gov (United States)

    Soboh, Basem; Igarashi, Robert Y; Hernandez, Jose A; Rubio, Luis M

    2006-12-01

    The NifEN protein complex serves as a molecular scaffold where some of the steps for the assembly of the iron-molybdenum cofactor (FeMo-co) of nitrogenase take place. A His-tagged version of the NifEN complex has been previously purified and shown to carry two identical [4Fe-4S] clusters of unknown function and a [Fe-S]-containing FeMo-co precursor. We have improved the purification of the his-NifEN protein from a DeltanifHDK strain of Azotobacter vinelandii and have found that the amounts of iron and molybdenum within NifEN were significantly higher than those reported previously. In an in vitro FeMo-co synthesis system with purified components, the NifEN protein served as a source of both molybdenum and a [Fe-S]-containing FeMo-co precursor, showing significant FeMo-co synthesis activity in the absence of externally added molybdate. Thus, the NifEN scaffold protein, purified from DeltanifHDK background, contained the Nif-Bco-derived Fe-S cluster and molybdenum, although these FeMo-co constituents were present at different levels within the protein complex. PMID:17012743

  18. The nature of nonfreezing water in carbohydrate polymers.

    Science.gov (United States)

    Kocherbitov, Vitaly

    2016-10-01

    In an aqueous environment, carbohydrate polymers are surrounded by hydration shells consisting of water molecules that are sometimes called "bound". When polymer solutions are subjected to low temperatures, a part of water turns into ice, another part remains in the biopolymer phase and is called "nonfreezing water". Thermodynamic analysis of water freezing shows that the amount of non-freezing water does not reflect the amount of bound water, neither can it be used as a measure of strength of polymer-water interactions. Upon deep cooling, crystallization of water should desiccate polymers more than is observed in experiment. The reason for existence of non-freezing water is an interplay between the crystallization of water and the glass transition in biopolymers that prevents dehydration. PMID:27312645

  19. A Causal Entropy Bound

    OpenAIRE

    Brustein, R; Veneziano, G

    1999-01-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic space-like region. This "causal entropy bound", scaling as the square root of EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various "critical" situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso...

  20. Towards complete hydrolysis of soy flour carbohydrates by enzyme mixtures for protein enrichment: A modeling approach.

    Science.gov (United States)

    Loman, Abdullah Al; Ju, Lu-Kwang

    2016-05-01

    Soy protein is a well-known nutritional supplement in proteinaceous food and animal feed. However, soybeans contain complex carbohydrate. Selective carbohydrate removal by enzymes could increase the protein content and remove the indigestibility of soy products for inclusion in animal feed. Complete hydrolysis of soy flour carbohydrates is challenging due to the presence of proteins and different types of non-structural polysaccharides. This study is designed to guide complex enzyme mixture required for hydrolysis of all types of soy flour carbohydrates. Enzyme broths from Aspergillus niger, Aspergillus aculeatus and Trichoderma reesei fermentations were evaluated in this study for soy carbohydrate hydrolysis. The resultant hydrolysate was measured for solubilized carbohydrate by both total carbohydrate and reducing sugar analyses. Conversion data attained after 48h hydrolysis were first fitted with models to determine the maximum fractions of carbohydrate hydrolyzable by each enzyme group, i.e., cellulase, xylanase, pectinase and α-galactosidase. Kinetic models were then developed to describe the increasing conversions over time under different enzyme activities and process conditions. The models showed high fidelity in predicting soy carbohydrate hydrolysis over broad ranges of soy flour loading (5-25%) and enzyme activities: per g soy flour, cellulase, 0.04-30 FPU; xylanase, 3.5-618U; pectinase, 0.03-120U; and α-galactosidase, 0.01-60U. The models are valuable in guiding the development and production of optimal enzyme mixtures toward hydrolysis of all types of carbohydrates present in soy flour and in optimizing the design and operation of hydrolysis reactor and process. PMID:26992789

  1. Alteration of the carbohydrate-binding specificity of a C-type lectin CEL-I mutant with an EPN carbohydrate-binding motif.

    Science.gov (United States)

    Hatakeyama, Tomomitsu; Ishimine, Tomohiro; Baba, Tomohiro; Kimura, Masanari; Unno, Hideaki; Goda, Shuichiro

    2013-07-01

    CEL-I is a Gal/GalNAc-specific C-type lectin isolated from the sea cucumber Cucumaria echinata. This lectin is composed of two carbohydrate-recognition domains (CRDs) with the carbohydrate-recognition motif QPD (Gln-Pro- Asp), which is generally known to exist in galactose-specific C-type CRDs. In the present study, a mutant CEL-I with EPN (Glu-Pro-Asn) motif, which is thought to be responsible for the carbohydrate-recognition of mannose-specific Ctype CRDs, was produced in Escherichia coli, and its effects on the carbohydrate-binding specificity were examined using polyamidoamine dendrimer (PD) conjugated with carbohydrates. Although wild-type CEL-I effectively formed complexes with N-acetylgalactosamine (GalNAc)-PD but not with mannose-PD, the mutant CEL-I showed relatively weak but definite affinity for mannose-PD. These results indicated that the QPD and EPN motifs play a significant role in the carbohydrate-recognition mechanism of CEL-I, especially in the discrimination of galactose and mannose. Additional mutations in the recombinant CEL-I binding site may further increase its specificity for mannose, and should provide insights into designing novel carbohydrate-recognition proteins. PMID:23157284

  2. New ruthenium nitrosyl complexes with tris(1-pyrazolyl)methane (tpm) and 2,2'-bipyridine (bpy) coligands. Structure, spectroscopy, and electrophilic and nucleophilic reactivities of bound nitrosyl.

    Science.gov (United States)

    Videla, Mariela; Jacinto, Julian S; Baggio, Ricardo; Garland, María T; Singh, Priti; Kaim, Wolfgang; Slep, Leonardo D; Olabe, José A

    2006-10-16

    The new compound [Ru(bpy)(tpm)NO](ClO4)3 [tpm = tris(1-pyrazolyl)methane; bpy = 2,2'-bipyridine] has been prepared in a stepwise procedure that involves the conversion of [Ru(bpy)(tpm)Cl]+ into the aqua and nitro intermediates, followed by acidification. The diamagnetic complex crystallizes to exhibit distorted octahedral geometry around the metal, with the Ru-N(O) bond length 1.774(12) A and the RuNO angle 179.1(12) degrees , typical for a {RuNO}6 description. The [Ru(bpy)(tpm)NO]3+ ion (I) has been characterized by 1H NMR and IR spectroscopies (nu(NO) = 1959 cm(-1)) and through density functional theory calculations. Intense electronic transitions in the 300-350-nm region are assigned through time-dependent (TD)DFT as intraligand pi --> pi for bpy and tpm. The dpi --> pi(bpy) metal-to-ligand charge-transfer transitions appear at higher energies. Aqueous cyclic voltammetric studies show a reversible wave at 0.31 V (vs Ag/AgCl, 3 M Cl-), which shifts to 0.60 V in MeCN, along with the onset of a wave of an irreversible process at -0.2 V. The waves are assigned to the one- and two-electron reductions centered at the NO ligand, leading to species with {RuNO}(7) and {RuNO}(8) configurations, respectively. Controlled potential reduction of I in MeCN led to the [Ru(bpy)(tpm)NO]2+ ion (II), revealing a significant downward shift of nu(NO) to 1660 cm(-1) as well as changes in the electronic absorption bands. II was also characterized by electron paramagnetic resonance, showing an anisotropic signal at 110 K that arises from an S = 1/2 electronic ground state; the g-matrix components and hyperfine coupling tensor resemble the behavior of related {RuNO}7 complexes. Both I and II were characterized through their main reactivity modes, electrophilic and nucleophilic, respectively. The addition of OH- into I generated the nitro complex, with k(OH) = 3.05 x 10(6) M(-1) s(-1) (25 degrees C). This value is among the highest obtained for related nitrosyl complexes and correlates

  3. Activities of a lagging DNA strand synthesis of nucleoprotein complexes harboring an extrachromosomal DNA closely related to avian myeloblastosis virus core-bound DNA

    International Nuclear Information System (INIS)

    Nucleoprotein (NP) complexes constituting the material of the post-microsomal sediment (POMS) and its three basic components (A, B, C), harboring an extrachromosomal DNA closely related to AMV DNA were found to.possess DNA- and RNA-synthesizing activities (SAs) reflecting the ability of this material to be intensely labelled for DNA and RNA, respectively. The types of these NA-SAs were compatible with those significant for a lagging DNA strand synthesis (LSS). The use of selective inhibitors and of the proliferating cell nuclear antigen (PCNA) disclosed a successive involvement of alpha DNA polymerase (pol) and PCNA-insensitive delta DNA pol in LSS. In this respect, we show gradual changes in the representation of activities (As) of both mentioned DNA pols in the NP complexes of the individual POMS components. Those of POMS component C contained alpha DNA pol As only, while a distinct portion of DNA SAs of POMS component B was represented on expense of alpha DNA pol As by PCNA-insensitive delta DNA pol (epsilon DNA pol), As which represented practically all the DNA SAs of POMS component A. The type of RNA SAs of this material represented mostly by primase (Pr) As corresponded well with the nature of LSS. An exception was represented by a minor portion of RNA-SAs of POMS component A which was alpha amanitine-sensitive like RNA pol II. Moreover, analyzing this natural model replication system, we found that the carbonyl diphosphonate (COMDP), a selective inhibitor of the PCNA-insensitive delta DNA pol, was a strong activator of Pr-As and/or Pr-alpha DNA pol As of NP complexes of POMS component C. (authors)

  4. A matrix lower bound

    Energy Technology Data Exchange (ETDEWEB)

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  5. A model for carbohydrate metabolism in the diatom Phaeodactylum tricornutum deduced from comparative whole genome analysis.

    Directory of Open Access Journals (Sweden)

    Peter G Kroth

    Full Text Available BACKGROUND: Diatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids. METHODOLOGY/PRINCIPAL FINDINGS: The whole genome sequence of the diatom Phaeodactylum tricornutum has recently been completed. We identified and annotated genes for enzymes involved in carbohydrate pathways based on extensive EST support and comparison to the whole genome sequence of a second diatom, Thalassiosira pseudonana. Protein localization to mitochondria was predicted based on identified similarities to mitochondrial localization motifs in other eukaryotes, whereas protein localization to plastids was based on the presence of signal peptide motifs in combination with plastid localization motifs previously shown to be required in diatoms. We identified genes potentially involved in a C4-like photosynthesis in P. tricornutum and, on the basis of sequence-based putative localization of relevant proteins, discuss possible differences in carbon concentrating mechanisms and CO(2 fixation between the two diatoms. We also identified genes encoding enzymes involved in photorespiration with one interesting exception: glycerate kinase was not found in either P. tricornutum or T. pseudonana. Various Calvin cycle enzymes were found in up to five different isoforms, distributed between plastids, mitochondria and the cytosol. Diatoms store energy either as lipids or as chrysolaminaran (a beta-1,3-glucan outside of the plastids. We identified various beta-glucanases and large membrane-bound glucan synthases. Interestingly most of the glucanases appear to contain C-terminal anchor domains that may attach the enzymes to membranes. CONCLUSIONS/SIGNIFICANCE: Here we present a detailed synthesis of carbohydrate metabolism in diatoms based on the genome sequences of Thalassiosira pseudonana and Phaeodactylum tricornutum

  6. X-Ray Crystal Structure of the Ancestral 3-Ketosteroid Receptor-Progesterone-Mifepristone Complex Shows Mifepristone Bound at the Coactivator Binding Interface

    Energy Technology Data Exchange (ETDEWEB)

    Colucci, Jennifer K.; Ortlund, Eric A. [Emory-MED

    2013-12-12

    Steroid receptors are a subfamily of nuclear receptors found throughout all metazoans. They are highly important in the regulation of development, inflammation, and reproduction and their misregulation has been implicated in hormone insensitivity syndromes and cancer. Steroid binding to SRs drives a conformational change in the ligand binding domain that promotes nuclear localization and subsequent interaction with coregulator proteins to affect gene regulation. SRs are important pharmaceutical targets, yet most SR-targeting drugs have off-target pharmacology leading to unwanted side effects. A better understanding of the structural mechanisms dictating ligand specificity and the evolution of the forces that created the SR-hormone pairs will enable the design of better pharmaceutical ligands. In order to investigate this relationship, we attempted to crystallize the ancestral 3-ketosteroid receptor (ancSR2) with mifepristone, a SR antagonist. Here, we present the x-ray crystal structure of the ancestral 3-keto steroid receptor (ancSR2)-progesterone complex at a resolution of 2.05 Å. This improves upon our previously reported structure of the ancSR2-progesterone complex, permitting unambiguous assignment of the ligand conformation within the binding pocket. Surprisingly, we find mifepristone, fortuitously docked at the protein surface, poised to interfere with coregulator binding. Recent attention has been given to generating pharmaceuticals that block the coregulator binding site in order to obstruct coregulator binding and achieve tissue-specific SR regulation independent of hormone binding. Mifepristone’s interaction with the coactivator cleft of this SR suggests that it may be a useful molecular scaffold for further coactivator binding inhibitor development.

  7. Recognition properties of receptors consisting of imidazole and indole recognition units towards carbohydrates

    Directory of Open Access Journals (Sweden)

    Monika Mazik

    2010-02-01

    Full Text Available Compounds 4 and 5, including both 4(5-substituted imidazole or 3-substituted indole units as the entities used in nature, and 2-aminopyridine group as a heterocyclic analogue of the asparagine/glutamine primary amide side chain, were prepared and their binding properties towards carbohydrates were studied. The design of these receptors was inspired by the binding motifs observed in the crystal structures of protein–carbohydrate complexes. 1H NMR spectroscopic titrations in competitive and non-competitive media as well as binding studies in two-phase systems, such as dissolution of solid carbohydrates in apolar media, revealed both highly effective recognition of neutral carbohydrates and interesting binding preferences of these acyclic compounds. Compared to the previously described acyclic receptors, compounds 4 and 5 showed significantly increased binding affinity towards β-galactoside. Both receptors display high β- vs. α-anomer binding preferences in the recognition of glycosides. It has been shown that both hydrogen bonding and interactions of the carbohydrate CH units with the aromatic rings of the receptors contribute to the stabilization of the receptor–carbohydrate complexes. The molecular modeling calculations, synthesis and binding properties of 4 and 5 towards selected carbohydrates are described and compared with those of the previously described receptors.

  8. Protective group strategies in carbohydrate and peptide chemistry

    OpenAIRE

    Ali, Asghar

    2010-01-01

    Protecting groups play a key role in the synthesis of complex natural products.This holds especially true for the synthesis of oligosaccharides, of which the monomeric carbohydrate building blocks usually contain up to five different hydroxyl functions. The discrimination of these hydroxyl functions requires a careful protecting group strategy and typically involves multistep protocols.This thesis describes the prepartion, installation, their use in the synthesis of stereoselective glycosidic...

  9. Physical Uncertainty Bounds (PUB)

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, Diane Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Dean L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-19

    This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

  10. Microbial oxidative sulfur metabolism: biochemical evidence of the membrane-bound heterodisulfide reductase-like complex of the bacterium Aquifex aeolicus.

    Science.gov (United States)

    Boughanemi, Souhela; Lyonnet, Jordan; Infossi, Pascale; Bauzan, Marielle; Kosta, Artémis; Lignon, Sabrina; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne

    2016-08-01

    The Hdr (heterodisulfide reductase)-like enzyme is predicted, from gene transcript profiling experiments previously published, to be essential in oxidative sulfur metabolism in a number of bacteria and archaea. Nevertheless, no biochemical and physicochemical data are available so far about this enzyme. Genes coding for it were identified in Aquifex aeolicus, a Gram-negative, hyperthermophilic, chemolithoautotrophic and microaerophilic bacterium that uses inorganic sulfur compounds as electron donor to grow. We provide biochemical evidence that this Hdr-like enzyme is present in this sulfur-oxidizing prokaryote (cultivated with thiosulfate or elemental sulfur). We demonstrate, by immunolocalization and cell fractionation, that Hdr-like enzyme is associated, presumably monotopically, with the membrane fraction. We show by co-immunoprecipitation assay or partial purification, that the Hdr proteins form a stable complex composed of at least five subunits, HdrA, HdrB1, HdrB2, HdrC1 and HdrC2, present in two forms of high molecular mass on native gel (∼240 and 450 kDa). These studies allow us to propose a revised model for dissimilatory sulfur oxidation pathways in A. aeolicus, with Hdr predicted to generate sulfite. PMID:27284018

  11. Crystal structure of the high-affinity Na+,K+-ATPase–ouabain complex with Mg2+ bound in the cation binding site

    DEFF Research Database (Denmark)

    Laursen, Mette; Yatime, Laure; Nissen, Poul; Fedosova, Natalya

    2013-01-01

    we describe a crystal structure of the phosphorylated pig kidney Na+,K+-ATPase in complex with the CTS representative ouabain, extending to 3.4 Å resolution. The structure provides key details on CTS binding, revealing an extensive hydrogen bonding network formed by the β-surface of the steroid core...... al. (2009) Proc Natl Acad Sci USA 106(33):13742–13747) shows that the CTS binding pocket of [Mg]E2P allows deep ouabain binding with possible long-range interactions between its polarized five-membered lactone ring and the Mg2+. K+ binding at the same site unwinds a turn of αM4, dragging residues Ile......318–Val325 toward the cation site and thereby hindering deep ouabain binding. Thus, the structural data establish a basis for the interpretation of the biochemical evidence pointing at direct K+–Mg2+ competition and explain the well-known antagonistic effect of K+ on CTS binding....

  12. Carbohydrate Microarrays in Plant Science

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik; Pedersen, H.L.; Vidal-Melgosa, S.; Ahl, Louise Isager; Salmean, A.A.; Egelund, Jack; Rydahl, Maja Gro; Clausen, M.H.; Willats, William George Tycho

    2012-01-01

    Almost all plant cells are surrounded by glycan-rich cell walls, which form much of the plant body and collectively are the largest source of biomass on earth. Plants use polysaccharides for support, defense, signaling, cell adhesion, and as energy storage, and many plant glycans are also importa...... plant research and can be used to map glycan populations across large numbers of samples to screen antibodies, carbohydrate binding proteins, and carbohydrate binding modules and to investigate enzyme activities.......Almost all plant cells are surrounded by glycan-rich cell walls, which form much of the plant body and collectively are the largest source of biomass on earth. Plants use polysaccharides for support, defense, signaling, cell adhesion, and as energy storage, and many plant glycans are also important...... industrially and nutritionally. Understanding the biological roles of plant glycans and the effective exploitation of their useful properties requires a detailed understanding of their structures, occurrence, and molecular interactions. Microarray technology has revolutionized the massively high...

  13. Carbohydrate metabolism in Spirochaeta stenostrepta.

    Science.gov (United States)

    Hespell, R B; Canale-Parola, E

    1970-07-01

    The pathways of carbohydrate metabolism in Spirochaeta stenostrepta, a free-living, strictly anaerobic spirochete, were studied. The organism fermented glucose to ethyl alcohol, acetate, lactate, CO(2), and H(2). Assays of enzymatic activities in cell extracts, and determinations of radioactivity distribution in products formed from (14)C-labeled glucose indicated that S. stenostrepta degraded glucose via the Embden-Meyerhof pathway. The spirochete utilized a clostridial-type clastic reaction to metabolize pyruvate to acetyl-coenzyme A, CO(2), and H(2), without production of formate. Acetyl-coenzyme A was converted to ethyl alcohol by nicotinamide adenine dinucleotide-dependent acetaldehyde and alcohol dehydrogenase activities. Phosphotransacetylase and acetate kinase catalyzed the formation of acetate from acetyl-coenzyme A. Hydrogenase and lactate dehydrogenase activities were detected in cell extracts. A rubredoxin was isolated from cell extracts of S. stenostrepta. Preparations of this rubredoxin stimulated acetyl phosphate formation from pyruvate by diethylaminoethyl cellulose-treated extracts of S. stenostrepta, an indication that rubredoxin may participate in pyruvate cleavage by this spirochete. Nutritional studies showed that S. stenostrepta fermented a variety of carbohydrates, but did not ferment amino acids or other organic acids. An unidentified growth factor present in yeast extract was required by the organism. Exogenous supplements of biotin, riboflavin, and vitamin B(12) were either stimulatory or required for growth. PMID:5423371

  14. Asymptotic Entropy Bounds

    CERN Document Server

    Bousso, Raphael

    2016-01-01

    We show that known entropy bounds constrain the information carried off by radiation to null infinity. We consider distant, planar null hypersurfaces in asymptotically flat spacetime. Their focussing and area loss can be computed perturbatively on a Minkowski background, yielding entropy bounds in terms of the energy flux of the outgoing radiation. In the asymptotic limit, we obtain boundary versions of the Quantum Null Energy Condition, of the Generalized Second Law, and of the Quantum Bousso Bound.

  15. Bound soliton fiber laser

    OpenAIRE

    Tang, D. Y.; B. Zhao; Shen, D. Y.; Lu, C.

    2009-01-01

    Experimental study on the soliton dynamics of a passively mode locked fiber ring laser firstly revealed a state of bound soliton operation in the laser, where two solitons bind together tightly with fixed pulse separation. We further report on the properties of the bound-soliton emission of the laser. In particular, we demonstrate both experimentally and numerically that, like the single pulse soliton operation of the laser, the bound soliton emission is another intrinsic feature of the laser.

  16. Complexity

    CERN Document Server

    Gershenson, Carlos

    2011-01-01

    The term complexity derives etymologically from the Latin plexus, which means interwoven. Intuitively, this implies that something complex is composed by elements that are difficult to separate. This difficulty arises from the relevant interactions that take place between components. This lack of separability is at odds with the classical scientific method - which has been used since the times of Galileo, Newton, Descartes, and Laplace - and has also influenced philosophy and engineering. In recent decades, the scientific study of complexity and complex systems has proposed a paradigm shift in science and philosophy, proposing novel methods that take into account relevant interactions.

  17. Biochemical software: Carbohydrates on Laboratory

    Directory of Open Access Journals (Sweden)

    D.N. Heidrich

    2005-07-01

    Full Text Available Educators around  the  world  are  being  challenged  to  develop  and  design  better and  more  effective strategies for student learning  using a variety  of modern  resources.  In this  present  work, an educa- tional  hypermedia  software  was constructed as a support tool to biochemistry teaching.  Occurrence, structure, main  characteristics and  biological  function  of the  biomolecule  Carbohydrates were pre- sented  through  modules.  The  software was developed  using concept  maps,  ISIS-Draw,  and  FLASH- MX animation program.  The chapter  Carbohydrates on Laboratory illustrates experimental methods of carbohydrates characterization, through  animation of a laboratory scenery.   The  subject was de- veloped showing reactions  as Bial, Benedict, Selliwanoff, Barfoed, Phenol  Sulphuric,  and Iodines, and also enzymatic  reactions  as glucose oxidase and amylase.  There are also links with short texts  in order to help the understanding of the contents  and principles of laboratory practice  as well as background reactions. Application of the software to undergraduate students and high school teachers  showed an excellent  acceptance.   All of them  considered  the  software  a very good learning  tool.  Both  teachers and students welcomed this program  as it is more flexible, and allows the learning in a more individual rhythm. In addition, application of the software would be suitable  to a more effective learning  and it is less expensive than conventional experimental teaching.

  18. Bounded Gaussian process regression

    DEFF Research Database (Denmark)

    Jensen, Bjørn Sand; Nielsen, Jens Brehm; Larsen, Jan

    2013-01-01

    We extend the Gaussian process (GP) framework for bounded regression by introducing two bounded likelihood functions that model the noise on the dependent variable explicitly. This is fundamentally different from the implicit noise assumption in the previously suggested warped GP framework. We...

  19. Mastering ectomycorrhizal symbiosis: the impact of carbohydrates.

    Science.gov (United States)

    Nehls, Uwe

    2008-01-01

    Mycorrhiza formation is the consequence of a mutualistic interaction between certain soil fungi and plant roots that helps to overcome nutritional limitations faced by the respective partners. In symbiosis, fungi contribute to tree nutrition by means of mineral weathering and mobilization of nutrients from organic matter, and obtain plant-derived carbohydrates as a response. Support with easily degradable carbohydrates seems to be the driving force for fungi to undergo this type of interaction. As a consequence, the fungal hexose uptake capacity is strongly increased in Hartig net hyphae of the model fungi Amanita muscaria and Laccaria bicolor. Next to fast carbohydrate uptake and metabolism, storage carbohydrates are of special interest. In functional A. muscaria ectomycorrhizas, expression and activity of proteins involved in trehalose biosynthesis is mainly localized in hyphae of the Hartig net, indicating an important function of trehalose in generation of a strong carbon sink by fungal hyphae. In symbiosis, fungal partners receive up to approximately 19 times more carbohydrates from their hosts than normal leakage of the root system would cause, resulting in a strong carbohydrate demand of infected roots and, as a consequence, a more efficient plant photosynthesis. To avoid fungal parasitism, the plant seems to have developed mechanisms to control carbohydrate drain towards the fungal partner and link it to the fungus-derived mineral nutrition. In this contribution, current knowledge on fungal strategies to obtain carbohydrates from its host and plant strategies to enable, but also to control and restrict (under certain conditions), carbon transfer are summarized. PMID:18272925

  20. Graviton Mass Bounds

    CERN Document Server

    de Rham, Claudia; Tolley, Andrew J; Zhou, Shuang-Yong

    2016-01-01

    Recently, aLIGO has announced the first direct detections of gravitational waves, a direct manifestation of the propagating degrees of freedom of gravity. The detected signals GW150914 and GW151226 have been used to examine the basic properties of these gravitational degrees of freedom, particularly setting an upper bound on their mass. It is timely to review what the mass of these gravitational degrees of freedom means from the theoretical point of view, particularly taking into account the recent developments in constructing consistent massive gravity theories. Apart from the GW150914 mass bound, a few other observational bounds have been established from the effects of the Yukawa potential, modified dispersion relation and fifth force that are all induced when the fundamental gravitational degrees of freedom are massive. We review these different mass bounds and examine how they stand in the wake of recent theoretical developments and how they compare to the bound from GW150914.

  1. Biochemical software: Carbohydrates on Laboratory

    OpenAIRE

    D.N. Heidrich; M.S.R.B. Figueiredo; R.V. Antonio,; da Costa, J. G.; P.B. Arantes; Figueiredo, L. F.; J.K. Sugai

    2005-01-01

    Educators around  the  world  are  being  challenged  to  develop  and  design  better and  more  effective strategies for student learning  using a variety  of modern  resources.  In this  present  work, an educa- tional  hypermedia  software  was constructed as a support tool to biochemistry teaching.  Occurrence, structure, main  characteristics and  biological  function  of the  biomolecule  Carbohydrates were pre- sented  through  modules.  The  software was developed  using concept  map...

  2. Facultative thermogenesis induced by carbohydrate

    DEFF Research Database (Denmark)

    Astrup, A; Bülow, J; Christensen, N J;

    1986-01-01

    In addition to the obligatory thermogenesis due to processing and storage, carbohydrate ingestion is accompanied by a facultative thermogenesis mediated by catecholamines via beta-adrenoceptors. The anatomical origin of facultative thermogenesis has hitherto not been determined. The possible...... involvement of skeletal muscle was examined in lean, healthy subjects by measuring the response in forearm oxygen consumption to an oral glucose load. The study demonstrates an early component of skeletal muscle thermogenesis coinciding with the local glucose uptake, followed by a late facultative...... thermogenesis. The arterial epinephrine concentration increased to a maximum of 200% above base-line values 4 h after glucose. This value greatly exceeds the physiological threshold for the thermogenic action of epinephrine. In forearm venous blood the corresponding increase in epinephrine was only...

  3. A mannanase, ManA, of the polycentric anaerobic fungus Orpinomyces sp. strain PC-2 has carbohydrate binding and docking modules.

    Science.gov (United States)

    Ximenes, Eduardo A; Chen, Huizhong; Kataeva, Irina A; Cotta, Michael A; Felix, Carlos R; Ljungdahl, Lars G; Li, Xin-Liang

    2005-07-01

    The anaerobic fungus Orpinomyces sp. strain PC-2 produces a broad spectrum of glycoside hydrolases, most of which are components of a high molecular mass cellulosomal complex. Here we report about a cDNA (manA) having 1924 bp isolated from the fungus and found to encode a polypeptide of 579 amino acid residues. Analysis of the deduced sequence revealed that it had a mannanase catalytic module, a family 1 carbohydrate-binding module, and a noncatalytic docking module. The catalytic module was homologous to aerobic fungal mannanases belonging to family 5 glycoside hydrolases, but unrelated to the previously isolated mannanases (family 26) of the anaerobic fungus Piromyces. No mannanase activity could be detected in Escherichia coli harboring a manA-containing plasmid. The manA was expressed in Saccharomyces cerevisiae and ManA was secreted into the culture medium in multiple forms. The purified extracellular heterologous mannanase hydrolyzed several types of mannan but lacked activity against cellulose, chitin, or beta-glucan. The enzyme had high specific activity toward locust bean mannan and an extremely broad pH profile. It was stable for several hours at 50 degrees C, but was rapidly inactivated at 60 degrees C. The carbohydrate-binding module of the Man A produced separately in E. coli bound preferably to insoluble lignocellulosic substrates, suggesting that it might play an important role in the complex enzyme system of the fungus for lignocellulose degradation. PMID:16175204

  4. Structural Bounds on the Dyadic Effect

    CERN Document Server

    Cinelli, Matteo; Iovanella, Antonio

    2016-01-01

    In this paper we consider the dyadic effect introduced in complex networks when nodes are distinguished by a binary characteristic. Under these circumstances two independent parameters, namely dyadicity and heterophilicity, are able to measure how much the assigned characteristic affects the network topology. All possible configurations can be represented in a phase diagram lying in a two-dimensional space that represents the feasible region of the dyadic effect, which is bound by two upper bounds on dyadicity and heterophilicity. Using some network's structural arguments, we are able to improve such upper bounds and introduce two new lower bounds, providing a reduction of the feasible region of the dyadic effect as well as constraining dyadicity and heterophilicity within a specific range. Some computational experiences show the bounds' effectiveness and their usefulness with regards to different classes of networks.

  5. Effect of soil carbohydrates on nutrient availability in natural forests and cultivated lands in Sri Lanka

    Science.gov (United States)

    Ratnayake, R. R.; Seneviratne, G.; Kulasooriya, S. A.

    2013-05-01

    Carbohydrates supply carbon sources for microbial activities that contribute to mineral nutrient production in soil. Their role on soil nutrient availability has not yet been properly elucidated. This was studied in forests and cultivated lands in Sri Lanka. Soil organic matter (SOM) fractions affecting carbohydrate availability were also determined. Soil litter contributed to sugars of plant origin (SPO) in croplands. The negative relationship found between clay bound organic matter (CBO) and glucose indicates higher SOM fixation in clay that lower its availability in cultivated lands. In forests, negative relationships between litter and sugars of microbial origin (SMO) showed that litter fuelled microbes to produce sugars. Fucose and glucose increased the availability of Cu, Zn and Mn in forests. Xylose increased Ca availability in cultivated lands. Arabinose, the main carbon source of soil respiration reduced the P availability. This study showed soil carbohydrates and their relationships with mineral nutrients could provide vital information on the availability of limiting nutrients in tropical ecosystems.

  6. Communication complexity and information complexity

    Science.gov (United States)

    Pankratov, Denis

    Information complexity enables the use of information-theoretic tools in communication complexity theory. Prior to the results presented in this thesis, information complexity was mainly used for proving lower bounds and direct-sum theorems in the setting of communication complexity. We present three results that demonstrate new connections between information complexity and communication complexity. In the first contribution we thoroughly study the information complexity of the smallest nontrivial two-party function: the AND function. While computing the communication complexity of AND is trivial, computing its exact information complexity presents a major technical challenge. In overcoming this challenge, we reveal that information complexity gives rise to rich geometrical structures. Our analysis of information complexity relies on new analytic techniques and new characterizations of communication protocols. We also uncover a connection of information complexity to the theory of elliptic partial differential equations. Once we compute the exact information complexity of AND, we can compute exact communication complexity of several related functions on n-bit inputs with some additional technical work. Previous combinatorial and algebraic techniques could only prove bounds of the form theta( n). Interestingly, this level of precision is typical in the area of information theory, so our result demonstrates that this meta-property of precise bounds carries over to information complexity and in certain cases even to communication complexity. Our result does not only strengthen the lower bound on communication complexity of disjointness by making it more exact, but it also shows that information complexity provides the exact upper bound on communication complexity. In fact, this result is more general and applies to a whole class of communication problems. In the second contribution, we use self-reduction methods to prove strong lower bounds on the information

  7. Properties of Excitons Bound to Ionized Donors

    DEFF Research Database (Denmark)

    Skettrup, Torben; Suffczynski, M.; Gorzkowski, W.

    1971-01-01

    Binding energies, interparticle distances, oscillator strengths, and exchange corrections are calculated for the three-particle complex corresponding to an exciton bound to an ionized donor. The results are given as functions of the mass ratio of the electron and hole. Binding of the complex is...

  8. Investigations of Reactive Carbohydrates in Glycosidic Bond Formation and Degradation

    DEFF Research Database (Denmark)

    Heuckendorff, Mads

    research was to develop new synthetic methods to evolve the field of synthetic carbohydrate chemistry. In addition, easy methods for obtaining complex oligosaccharides are needed to accommodate biochemical research and drug development. Furthermore, the aim was to shed light on the complex mechanisms of...... configuration and the type of functional group installed on the 2-OH. In Chapter 3 the concepts of conformationally and anchimerically arming were combined in order to achieve the synthesis of a novel donor. The new donor’s capabilities in glycosylations are described. In Chapter 4 a new method for making...

  9. 31P and 1H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

    International Nuclear Information System (INIS)

    The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of 31P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the δ protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of 31P relaxation rates in E-MnADP and E-MnATP yields activation energies (ΔE) in the range 6-10 kcal/mol. Thus, the 31P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and ΔE values in the range 1-2 kcal/mol; i.e., these rates depend upon 31P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 angstrom, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the 1H spin-lattice relaxation rate of the δ protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective τC of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate (τS1) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the δ protons was 10.9 ± 0.3 angstrom

  10. Deeply bound pionic atom

    International Nuclear Information System (INIS)

    The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ-) cross sections are estimated. (p, 2Heπ-) reaction would have cross sections similar to the cross section of (n, dπ-) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

  11. Continuous bounded cohomology of locally compact groups

    CERN Document Server

    2001-01-01

    Recent research has repeatedly led to connections between important rigidity questions and bounded cohomology. However, the latter has remained by and large intractable. This monograph introduces the functorial study of the continuous bounded cohomology for topological groups, with coefficients in Banach modules. The powerful techniques of this more general theory have successfully solved a number of the original problems in bounded cohomology. As applications, one obtains, in particular, rigidity results for actions on the circle, for representations on complex hyperbolic spaces and on Teichmüller spaces. A special effort has been made to provide detailed proofs or references in quite some generality.

  12. Generalized Sphere Packing Bound

    OpenAIRE

    Fazeli, Arman; Vardy, Alexander; Yaakobi, Eitan

    2014-01-01

    Kulkarni and Kiyavash recently introduced a new method to establish upper bounds on the size of deletion-correcting codes. This method is based upon tools from hypergraph theory. The deletion channel is represented by a hypergraph whose edges are the deletion balls (or spheres), so that a deletion-correcting code becomes a matching in this hypergraph. Consequently, a bound on the size of such a code can be obtained from bounds on the matching number of a hypergraph. Classical results in hyper...

  13. Sample Complexity Bounds for Differentially Private Learning

    OpenAIRE

    Chaudhuri, Kamalika; Hsu, Daniel

    2011-01-01

    This work studies the problem of privacy-preserving classification – namely, learning a classifier from sensitive data while preserving the privacy of individuals in the training set. In particular, the learning algorithm is required in this problem to guarantee differential privacy, a very strong notion of privacy that has gained significant attention in recent years.

  14. Lower Bounds on Quantum Query Complexity

    NARCIS (Netherlands)

    P. Hoyer; R. Spalek

    2005-01-01

    Shor's and Grover's famous quantum algorithms for factoring and searching show that quantum computers can solve certain computational problems significantly faster than any classical computer. We discuss here what quantum computers cannot do, and specifically how to prove limits on their computation

  15. Lower complexity bounds for lifted inference

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2015-01-01

    probabilistic relational models. Artificial Intelligence 117, 297–308). However, it is not immediate that these results also apply to the type of modeling languages that currently receive the most attention, i.e., weighted, quantifier-free formulas. In this paper we extend these earlier results, and show......One of the big challenges in the development of probabilistic relational (or probabilistic logical) modeling and learning frameworks is the design of inference techniques that operate on the level of the abstract model representation language, rather than on the level of ground, propositional...

  16. Phylogenetic diversity of carbohydrate degrading culturable bacteria from Mandovi and Zuari estuaries, Goa, west coast of India

    Science.gov (United States)

    Khandeparker, Rakhee; Verma, Preeti; Meena, Ram M.; Deobagkar, Deepti D.

    2011-12-01

    Coastal and estuarine waters are highly productive and dynamic ecosystems. The complex carbohydrate composition of the ecosystem would lead to colonisation of microbial communities with abilities to produce an array of complex carbohydrate degrading enzymes. We have examined the abundance and phylogenetic diversity of culturable bacteria with abilities to produce complex carbohydrate degrading enzymes in the Mondovi and Zuari eustauri. It was interesting to note that 65% of isolated bacteria could produce complex carbohydrate degrading enzymes. A majority of these bacteria belonged to Bacillus genera followed by Vibrio, Marinobacter, Exiquinobacterium, Alteromonas, Enterobacter and Aeromonas. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. It was seen that 46% of Bacillus had ability to degrade both the substrate while only 14% of Vibrio had bifunctionality.

  17. Deeply bound pionic states

    International Nuclear Information System (INIS)

    We discuss the structure and formation of deeply bound π- states in heavy nuclei, which are expected to be narrow due to the repulsive π--nucleus interaction. Possible experiments to produce those states are described. (author)

  18. Carbohydrates - Guidelines on Parenteral Nutrition, Chapter 5

    OpenAIRE

    Bolder, U; Ebener, C.; Hauner, H.; Jauch, KW; Kreymann, G.; Ockenga, J.; Traeger, K.; Working group for developing the guidelines for parenteral nutrition of The German Association for Nutritional Medicine

    2009-01-01

    The main role of carbohydrates in the human body is to provide energy. Carbohydrates should always be infused with PN (parenteral nutrition) in combination with amino acids and lipid emulsions to improve nitrogen balance. Glucose should be provided as a standard carbohydrate for PN, whereas the use of xylite is not generally recommended. Fructose solutions should not be used for PN. Approximately 60% of non-protein energy should be supplied as glucose with an intake of 3.0-3.5 g/kg body weigh...

  19. Utilization of carbohydrates by radiation processing

    Science.gov (United States)

    Kume, T.; Nagasawa, N.; Yoshii, F.

    2002-03-01

    Upgrading and utilization of carbohydrates such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated for recycling these bio-resources and reducing the environmental pollution. These carbohydrates were easily degraded by irradiation and various kinds of biological activities such as anti-microbial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction, etc. were induced. On the other hand, some carbohydrate derivatives, carboxymethylcellulose and carboxymethylstarch, could be crosslinked under certain radiation condition and produce the biodegradable hydrogel for medical and agricultural use.

  20. Selective preservation of carbohydrates in volcanic ash soils

    Science.gov (United States)

    Kaal, J.; Buurman, P.; Nierop, K. G. J.; Piccolo, A.

    2009-04-01

    Volcanic soils (Andosols) are formed in volcanic ash and depending on environmental and climatic factors they develop to two main forms, either allophanic Andosols (dominated by amorphous minerals) or non-allophanic Andosols (dominated by Al/Fe organic matter complexes). Andosols contain the largest amounts of organic carbon of all mineral soil orders. In recent studies using analytical pyrolysis techniques on the soil organic matter (SOM) of allophanic soils from the Azores Islands (Portugal) there was no indication of preservation of plant-derived organic matter by allophane or Al3+, but the presence of large amounts of (microbial) polysaccharides and chitin suggested that secondary organic matter products were stabilized. In the present study we used 13C NMR to further explore the organic matter of the Andosols of the Azores, and applied a molecular mixing model (MMM; ascribing characteristic resonances to the main biocomponent classes carbohydrate, protein, lipid, lignin and char) to the quantified NMR spectra to allow for a quantitative comparison with pyrolysis-GC/MS. The dominance of O-alkyl and di-O-alkyl C in the NMR spectra and carbohydrate contribution to the predictions made by the MMM (50 ± 8%) confirms that the majority of the SOM can still be recognised as carbohydrate. The accumulation of secondary/microbial carbohydrates (and, to a lesser extent, secondary proteinaceous matter and chitins) is thus a key characteristic of these Andosols. NMR-MMM and pyrolysis-GC/MS were in rough agreement. However, NMR does not recognise chitin (N-containing carbohydrate-like material) and chitin-associated protein, nor can it be used to estimate the degree of degradation of the carbohydrates. Therefore, NMR (as applied here) has a very limited capacity for characterisation of the SOM particularly in the Andosols studied. On the other hand, large peaks from carboxylic and amidic functional groups detected by NMR were not observed by pyrolysis-GC/MS. It is therefore

  1. Lanthanide-IMAC enrichment of carbohydrates and polyols.

    Science.gov (United States)

    Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

    2014-03-01

    In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions. PMID:24097333

  2. How mushrooms feed on compost: conversion of carbohydrates and linin in industrial wheat straw based compost enabling the growth of Agaricus bisporus

    OpenAIRE

    Jurak, E.

    2015-01-01

    Abstract In this thesis, the fate of carbohydrates and lignin was studied in industrial wheat straw based compost during composting and growth of Agaricus bisporus. The aim was to understand the availability and degradability of carbohydrates in order to help improve their utilization in the compost. The wheat straw based compost was characterized as being composed mainly of cellulose and lowly substituted xylan. During the first phase of composting, ester-bound substituents were removed from...

  3. A functional glycoprotein competitive recognition and signal amplification strategy for carbohydrate-protein interaction profiling and cell surface carbohydrate expression evaluation

    Science.gov (United States)

    Wang, Yangzhong; Chen, Zhuhai; Liu, Yang; Li, Jinghong

    2013-07-01

    A simple and sensitive carbohydrate biosensor has been suggested as a potential tool for accurate analysis of cell surface carbohydrate expression as well as carbohydrate-based therapeutics for a variety of diseases and infections. In this work, a sensitive biosensor for carbohydrate-lectin profiling and in situ cell surface carbohydrate expression was designed by taking advantage of a functional glycoprotein of glucose oxidase acting as both a multivalent recognition unit and a signal amplification probe. Combining the gold nanoparticle catalyzed luminol electrogenerated chemiluminescence and nanocarrier for active biomolecules, the number of cell surface carbohydrate groups could be conveniently read out. The apparent dissociation constant between GOx@Au probes and Con A was detected to be 1.64 nM and was approximately 5 orders of magnitude smaller than that of mannose and Con A, which would arise from the multivalent effect between the probe and Con A. Both glycoproteins and gold nanoparticles contribute to the high affinity between carbohydrates and lectin. The as-proposed biosensor exhibits excellent analytical performance towards the cytosensing of K562 cells with a detection limit of 18 cells, and the mannose moieties on a single K562 cell were determined to be 1.8 × 1010. The biosensor can also act as a useful tool for antibacterial drug screening and mechanism investigation. This strategy integrates the excellent biocompatibility and multivalent recognition of glycoproteins as well as the significant enzymatic catalysis and gold nanoparticle signal amplification, and avoids the cell pretreatment and labelling process. This would contribute to the glycomic analysis and the understanding of complex native glycan-related biological processes.A simple and sensitive carbohydrate biosensor has been suggested as a potential tool for accurate analysis of cell surface carbohydrate expression as well as carbohydrate-based therapeutics for a variety of diseases and

  4. Lectures on Bound states

    CERN Document Server

    Hoyer, Paul

    2016-01-01

    Even a first approximation of bound states requires contributions of all powers in the coupling. This means that the concept of "lowest order bound state" needs to be defined. In these lectures I discuss the "Born" (no loop, lowest order in $\\hbar$) approximation. Born level states are bound by gauge fields which satisfy the classical field equations. As a check of the method, Positronium states of any momentum are determined as eigenstates of the QED Hamiltonian, quantized at equal time. Analogously, states bound by a strong external field $A^\\mu(\\xv)$ are found as eigenstates of the Dirac Hamiltonian. Their Fock states have dynamically created $e^+e^-$ pairs, whose distribution is determined by the Dirac wave function. The linear potential of $D=1+1$ dimensions confines electrons but repels positrons. As a result, the mass spectrum is continuous and the wave functions have features of both bound states and plane waves. The classical solutions of Gauss' law are explored for hadrons in QCD. A non-vanishing bo...

  5. Bounding species distribution models

    Institute of Scientific and Technical Information of China (English)

    Thomas J. STOHLGREN; Catherine S. JARNEVICH; Wayne E. ESAIAS; Jeffrey T. MORISETTE

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern.Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development,yet there is no recommended best practice for “clamping” model extrapolations.We relied on two commonly used modeling approaches:classification and regression tree (CART) and maximum entropy (Maxent) models,and we tested a simple alteration of the model extrapolations,bounding extrapolations to the maximum and minimum values of primary environmental predictors,to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States.Findings suggest that multiple models of bounding,and the most conservative bounding of species distribution models,like those presented here,should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5):642-647,2011].

  6. Carbohydrate Nutrition and Team Sport Performance.

    Science.gov (United States)

    Williams, Clyde; Rollo, Ian

    2015-11-01

    The common pattern of play in 'team sports' is 'stop and go', i.e. where players perform repeated bouts of brief high-intensity exercise punctuated by lower intensity activity. Sprints are generally 2-4 s long and recovery between sprints is of variable length. Energy production during brief sprints is derived from the degradation of intra-muscular phosphocreatine and glycogen (anaerobic metabolism). Prolonged periods of multiple sprints drain muscle glycogen stores, leading to a decrease in power output and a reduction in general work rate during training and competition. The impact of dietary carbohydrate interventions on team sport performance have been typically assessed using intermittent variable-speed shuttle running over a distance of 20 m. This method has evolved to include specific work to rest ratios and skills specific to team sports such as soccer, rugby and basketball. Increasing liver and muscle carbohydrate stores before sports helps delay the onset of fatigue during prolonged intermittent variable-speed running. Carbohydrate intake during exercise, typically ingested as carbohydrate-electrolyte solutions, is also associated with improved performance. The mechanisms responsible are likely to be the availability of carbohydrate as a substrate for central and peripheral functions. Variable-speed running in hot environments is limited by the degree of hyperthermia before muscle glycogen availability becomes a significant contributor to the onset of fatigue. Finally, ingesting carbohydrate immediately after training and competition will rapidly recover liver and muscle glycogen stores. PMID:26553494

  7. Validation of EMP bounds

    Energy Technology Data Exchange (ETDEWEB)

    Warne, L.K.; Merewether, K.O.; Chen, K.C.; Jorgenson, R.E.; Morris, M.E.; Solberg, J.E.; Lewis, J.G. [Sandia National Labs., Albuquerque, NM (United States); Derr, W. [Derr Enterprises, Albuquerque, NM (United States)

    1996-07-01

    Test data on canonical weapon-like fixtures are used to validate previously developed analytical bounding results. The test fixtures were constructed to simulate (but be slightly worse than) weapon ports of entry but have known geometries (and electrical points of contact). The exterior of the test fixtures exhibited exterior resonant enhancement of the incident fields at the ports of entry with magnitudes equal to those of weapon geometries. The interior consisted of loaded transmission lines adjusted to maximize received energy or voltage but incorporating practical weapon geometrical constraints. New analytical results are also presented for bounding the energies associated with multiple bolt joints and for bounding the exterior resonant enhancement of the exciting fields.

  8. Information, Utility & Bounded Rationality

    CERN Document Server

    Ortega, Pedro A

    2011-01-01

    Perfectly rational decision-makers maximize expected utility, but crucially ignore the resource costs incurred when determining optimal actions. Here we employ an axiomatic framework for bounded rational decision-making based on a thermodynamic interpretation of resource costs as information costs. This leads to a variational "free utility" principle akin to thermodynamical free energy that trades off utility and information costs. We show that bounded optimal control solutions can be derived from this variational principle, which leads in general to stochastic policies. Furthermore, we show that risk-sensitive and robust (minimax) control schemes fall out naturally from this framework if the environment is considered as a bounded rational and perfectly rational opponent, respectively. When resource costs are ignored, the maximum expected utility principle is recovered.

  9. Impact of lignin and carbohydrate chemical structures on degradation reactions during hardwood kraft pulping processes

    Directory of Open Access Journals (Sweden)

    Ricardo B. Santos

    2013-02-01

    Full Text Available Most studies aimed at determining rates of hardwood delignification and carbohydrate degradation have focused on understanding the behavior of a single wood species. Such studies tend to determine either the delignification rate or the rate of carbohydrate degradation without examining the potential interactions resulting from related variables. The current study provides a comprehensive evaluation on both lignin and carbohydrate degradation during kraft pulping of multiple hardwood species. The kraft delignification rates of E. urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, red alder, cottonwood, and acacia were obtained. Furthermore, the kinetics of glucan, xylan, and total carbohydrate dissolution during the bulk phase of the kraft pulping process for the above species were also investigated. The wide ranges of delignification and carbohydrate degradation rates were correlated to wood chemical characteristics. It appears that the S/G ratio and lignin-carbohydrate-complexes (LCCs are the main characteristics responsible for the differences in kraft pulping performance among the hardwoods studied.

  10. Isolation of prebiotic carbohydrates by supercritical fluid extraction. Scaling-up and economical feasibility.

    Science.gov (United States)

    Montañés, F; Fornari, T; Olano, A; Ibáñez, E

    2012-08-10

    Production of prebiotic carbohydrates at competitive prices is a challenge nowadays since the well-established production processes involve many purification steps which are labour intensive and require important amounts of reagents and products thus increasing prebiotic's price. Several processes have been studied in our laboratory involving the use of Supercritical Fluid Technology to fractionate and purify carbohydrate solid mixtures. Research carried out at laboratory scale using theoretical mixtures (lactose/lactulose and galactose/tagatose), commercially available carbohydrate mixtures and carbohydrate mixtures produced by enzymatic transglycosylation and isomerized with complexating reagents demonstrated that purification of prebiotic carbohydrates was technically possible by supercritical fluid extraction. In the present work, the process optimized at laboratory scale to fractionate carbohydrate mixtures produced by enzymatic transglycosylation has been scaled-up to an industrial level and its economic feasibility has been simulated employing AspenONE(®) V7.3 software to obtain consistent data supporting the interest of a potential investment for prebiotics production at large scale using supercritical fluids. PMID:22560345

  11. The Chemical Neurobiology of Carbohydrates

    OpenAIRE

    Murrey, Heather E.; Hsieh-Wilson, Linda C.

    2008-01-01

    The cell surface displays a complex array of oligosaccharides, glycoproteins, and glycolipids. This diverse mixture of glycans contains a wealth of information, modulating a wide range of processes such as cell migration, proliferation, transcriptional regulation, and differentiation. Glycosylation is one of the most ubiquitous forms of post-translational modification, with more than 50% of the human proteome estimated to be glycosylated. Glycosylation adds another dimension to the complexity...

  12. Metabolic aspects of low carbohydrate diets and exercise

    Directory of Open Access Journals (Sweden)

    Peters Sandra

    2004-01-01

    Full Text Available Abstract Following a low carbohydrate diet, there is a shift towards more fat and less carbohydrate oxidation to provide energy to skeletal muscle, both at rest and during exercise. This review summarizes recent work on human skeletal muscle carbohydrate and fat metabolic adaptations to a low carbohydrate diet, focusing mainly on pyruvate dehydrogenase and pyruvate dehydrogenase kinase, and how these changes relate to the capacity for carbohydrate oxidation during exercise.

  13. Bounded variation and around

    CERN Document Server

    Appell, Jürgen; Merentes Díaz, Nelson José

    2013-01-01

    This monographis a self-contained exposition of the definition and properties of functionsof bounded variation and their various generalizations; the analytical properties of nonlinear composition operators in spaces of such functions; applications to Fourier analysis, nonlinear integral equations, and boundary value problems. The book is written for non-specialists. Every chapter closes with a list of exercises and open problems.

  14. Effect of carbohydrate ingestion subsequent to carbohydrate supercompensation on endurance performance.

    Science.gov (United States)

    Kang, J; Robertson, R J; Denys, B G; DaSilva, S G; Visich, P; Suminski, R R; Utter, A C; Goss, F L; Metz, K F

    1995-12-01

    This investigation determined whether carbohydrate ingestion during prolonged moderate-intensity exercise enhanced endurance performance when the exercise was preceded by carbohydrate supercompensation. Seven male trained cyclists performed two trials at an initial power output corresponding to 71 +/- 1% of their peak oxygen consumption. During the trials, subjects ingested either a 6% glucose/sucrose (C) solution or an equal volume of artificially flavored and sweetened placebo (P) every 20 min throughout exercise. Both C and P were preceded by a 6-day carbohydrate supercompensation procedure in which subjects undertook a depletion-taper exercise sequence in conjunction with a moderate- and high-carbohydrate diet regimen. Statistical analysis of time to exhaustion, plasma glucose concentration, carbohydrate oxidation rate, fat oxidation rate, and plasma glycerol concentration indicated that in spite of a carbohydrate supercompensation procedure administered prior to exercise, carbohydrate ingestion during exercise can exert an additional ergogenic effect by preventing a decline in blood glucose levels and maintaining carbohydrate oxidation during the later stages of moderate-intensity exercise. PMID:8605519

  15. Carbohydrate mouth rinse and caffeine improves high-intensity interval running capacity when carbohydrate restricted.

    Science.gov (United States)

    Kasper, Andreas M; Cocking, Scott; Cockayne, Molly; Barnard, Marcus; Tench, Jake; Parker, Liam; McAndrew, John; Langan-Evans, Carl; Close, Graeme L; Morton, James P

    2016-08-01

    We tested the hypothesis that carbohydrate mouth rinsing, alone or in combination with caffeine, augments high-intensity interval (HIT) running capacity undertaken in a carbohydrate-restricted state. Carbohydrate restriction was achieved by performing high-intensity running to volitional exhaustion in the evening prior to the main experimental trials and further refraining from carbohydrate intake in the post-exercise and overnight period. On the subsequent morning, eight males performed 45-min steady-state (SS) exercise (65% [Formula: see text]) followed by HIT running to exhaustion (1-min at 80% [Formula: see text]interspersed with 1-min walking at 6 km/h). Subjects completed 3 trials consisting of placebo capsules (administered immediately prior to SS and immediately before HIT) and placebo mouth rinse at 4-min intervals during HIT (PLACEBO), placebo capsules but 10% carbohydrate mouth rinse (CMR) at corresponding time-points or finally, caffeine capsules (200 mg per dose) plus 10% carbohydrate mouth rinse (CAFF + CMR) at corresponding time-points. Heart rate, capillary glucose, lactate, glycerol and NEFA were not different at exhaustion during HIT (P > 0.05). However, HIT capacity was different (P mouth rinsing and caffeine ingestion improves exercise capacity undertaken in carbohydrate-restricted states. Such nutritional strategies may be advantageous for those athletes who deliberately incorporate elements of training in carbohydrate-restricted states (i.e. the train-low paradigm) into their overall training programme in an attempt to strategically enhance mitochondrial adaptations of skeletal muscle. PMID:26035740

  16. Bounded Quadrant System: Error-bounded Trajectory Compression on the Go

    OpenAIRE

    Liu, Jiajun; Zhao, Kun; Sommer, Philipp; Shang, Shuo; Kusy, Brano; Jurdak, Raja

    2014-01-01

    Long-term location tracking, where trajectory compression is commonly used, has gained high interest for many applications in transport, ecology, and wearable computing. However, state-of-the-art compression methods involve high space-time complexity or achieve unsatisfactory compression rate, leading to rapid exhaustion of memory, computation, storage and energy resources. We propose a novel online algorithm for error-bounded trajectory compression called the Bounded Quadrant System (BQS), w...

  17. Asynchronous Bounded Expected Delay Networks

    OpenAIRE

    Bakhshi, Rena; Endrullis, Jörg; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In ...

  18. On Entropy Bounds and Holography

    CERN Document Server

    Halyo, Edi

    2009-01-01

    We show that the holographic entropy bound for gravitational systems and the Bekenstein entropy bound for nongravitational systems are holographically related. Using the AdS/CFT correspondence, we find that the Bekenstein bound on the boundary is obtained from the holographic bound in the bulk by minimizing the boundary energy with respect the AdS radius or the cosmological constant. This relation may also ameliorate some problems associated with the Bekenstein bound.

  19. Potential effect of ultrasound on carbohydrates.

    Science.gov (United States)

    Bera, Smritilekha; Mondal, Dhananjoy; Martin, Jacob T; Singh, Man

    2015-06-17

    The use of ultrasound has emerged as one of the most useful alternative energy sources for the synthesis of carbohydrate-derived biologically and pharmaceutically potential compounds. Spectacular advances have been made in the field of sonication-assisted organic reactions, which are known for producing superior yields, enhanced reactivity of the reactant, improved stereoselectivity, and shortened reaction times. Orthogonal protection-deprotection reactions and/or modification and manipulation of functional groups in carbohydrates are common synthetic steps in carbohydrate chemistry. These reaction steps can be driven by the ultrasonic energy generated by acoustic cavitation via the formation and subsequent collapse of ultrasound-induced bubbles. The ultrasound-assisted synthesis of differently functionalised monosaccharides is useful in a wide variety of applications of carbohydrate chemistry such as the glycosylation of oligosaccharides, one pot domino reactions, thioglycoside syntheses, azidoglycoside syntheses, 1,3-dipolar cycloaddition reactions, and syntheses of natural products. This review article covers ultrasound-mediated reactions on carbohydrates that have been described in the literature since 2000. PMID:25954862

  20. Bounded Tamper Resilience

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Faust, Sebastian; Mukherjee, Pratyay; Venturi, Daniele

    Related key attacks (RKAs) are powerful cryptanalytic attacks where an adversary can change the secret key and observe the effect of such changes at the output. The state of the art in RKA security protects against an a-priori unbounded number of certain algebraic induced key relations, e...... bounded tamper and leakage resilient CCA secure public key cryptosystem based on the DDH assumption. We first define a weaker CPA-like security notion that we can instantiate based on DDH, and then we give a general compiler that yields CCA-security with tamper and leakage resilience. This requires a...... public tamper-proof common reference string. Finally, we explain how to boost bounded tampering and leakage resilience (as in 1. and 2. above) to continuous tampering and leakage resilience, in the so-called floppy model where each user has a personal hardware token (containing leak- and tamper...

  1. Deeply bound $\\Xi$ tribaryon

    CERN Document Server

    Garcilazo, H

    2016-01-01

    We have used realistic local interactions based on the recent update of the strangeness $-2$ Nijmegen ESC08c potential to calculate the bound state problem of the $\\Xi NN$ system in the $(I)J^P=(\\frac{1}{2})\\frac{3}{2}^+$ state. We found that this system presents a deeply bound state lying $13.5$ MeV below the $\\Xi d$ threshold. Since in lowest order, pure S$-$wave configuration, this system can not decay into the open $\\Lambda\\Lambda N$ channel, its decay width is expected to be very small. We have also recalculated the $(I)J^P=(\\frac{3}{2})\\frac{1}{2}^+$ state and we have compared with results of quark-model based potentials.

  2. Petawatt laser absorption bounded

    CERN Document Server

    Levy, Matthew C; Tabak, Max; Libby, Stephen B; Baring, Matthew G

    2014-01-01

    The interaction of petawatt ($10^{15}\\ \\mathrm{W}$) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light $f$, and even the range of $f$ is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that $f$ exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  3. Towards Secure Distance Bounding

    OpenAIRE

    Boureanu, Ioana; Mitrokotsa, Aikaterini; Vaudenay, Serge

    2013-01-01

    Relay attacks (and, more generally, man-in-the-middle attacks) are a serious threat against many access control and payment schemes. In this work, we present distance-bounding protocols, how these can deter relay attacks, and the security models formalizing these protocols. We show several pitfalls making existing protocols insecure (or at least, vulnerable, in some cases). Then, we introduce the SKI protocol which enjoys resistance to all popular attack-models and features provable security....

  4. Maps of Bounded Rationality

    OpenAIRE

    Kahneman, Daniel

    2002-01-01

    The work cited by the Nobel committee was done jointly with the late Amos Tversky (1937-1996) during a long and unusually close collaboration. Together, we explored the psychology of intuitive beliefs and choices and examined their bounded rationality. This essay presents a current perspective on the three major topics of our joint work: heuristics of judgment, risky choice, and framing effects. In all three domains we studied intuitions - thoughts and preferences that come to mind quickly an...

  5. Bounded Active Perception

    OpenAIRE

    KETENCI, Uktu Gorkem; Bremond, Roland; Auberlet, Jean Michel; GRISLIN, Emmanuelle

    2010-01-01

    There are two kinds of perception : active and passive. This paper is an attempt to take advantage of active perception to improve the agent's perception of relevant information. Through the data filtering capacity, active perception is a useful tool for modeling human-like bounded perception. Using such filters, either the agent or the environment take an active role. We determine several unsolved issues in active perception and do several proposals to implement our concept on the active per...

  6. Bounded Discrete Walks

    OpenAIRE

    Banderier, Cyril; Nicodeme, Pierre

    2010-01-01

    This article tackles the enumeration and asymptotics of directed lattice paths (that are isomorphic to unidimensional paths) of bounded height (walks below one wall, or between two walls, for \\emphany finite set of jumps). Thus, for any lattice paths, we give the generating functions of bridges (``discrete'' Brownian bridges) and reflected bridges (``discrete'' reflected Brownian bridges) of a given height. It is a new success of the ``kernel method'' that the generating functions of such wal...

  7. Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates.

    Science.gov (United States)

    Nishiyama, Keita; Ueno, Shintaro; Sugiyama, Makoto; Yamamoto, Yuji; Mukai, Takao

    2016-06-01

    Lactobacillus rhamnosus GG (LGG) is a well-established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme-linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance-based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β-galactoside at the non-reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β-galactoside at the non-reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions. PMID:26434750

  8. Reflecting Magnon Bound States

    CERN Document Server

    Ahn, C; Rey, S J

    2008-01-01

    In N=4 super Yang-Mills spin chain, we compute reflection amplitudes of magnon bound-state off giant graviton. We first compute the reflection amplitude off Y=0 brane boundary and compare it with the scattering amplitude between two magnon bound-states in the bulk. We find that analytic structure of the two amplitudes are intimately related each other: the boundary reflection amplitude is a square-root of the bulk scattering amplitude. Using such relation as a guide and taking known results at weak and strong coupling limits as inputs, we find the reflection amplitude of an elementary magnon off Z=0 giant graviton boundary. The reflection phase factor is shown to solve crossing and unitarity relations. We then compute the reflection amplitude of magnon bound-state off the Z=0 brane boundary and observe that its analytic structures are again intimately related to the bulk scattering and the Y=0 boundary reflection amplitudes. We also take dyonic giant magnon limit of these reflection amplitudes and confirm tha...

  9. Synthetic Strategies for Converting Carbohydrates into Carbocycles by the Use of Olefin Metathesis

    DEFF Research Database (Denmark)

    Madsen, Robert

    2007-01-01

    , protecting groups and substituents. Subsequent ring-closing metathesis with a ruthenium carbene complex affords highly functionalized carbocycles with ring-sizes ranging from five- to eight-membered rings. The application of these methods for the synthesis of carbocyclic natural products from carbohydrates...

  10. Antibaryon-nucleus bound states

    CERN Document Server

    Hrtánková, J

    2014-01-01

    We calculated antibaryon ($\\bar{B}$ = $\\bar{p}$, $\\bar{\\Lambda}$, $\\bar{\\Sigma}$, $\\bar{\\Xi}$) bound states in selected nuclei within the relativistic mean-field (RMF) model. The G-parity motivated $\\bar{B}$-meson coupling constants were scaled to yield corresponding potentials consistent with available experimental data. Large polarization of the nuclear core caused by $\\bar{B}$ was confirmed. The $\\bar{p}$ annihilation in the nuclear medium was incorporated by including a phenomenological imaginary part of the optical potential. The calculations using a complex $\\bar{p}$-nucleus potential were performed fully self-consistently. The $\\bar{p}$ widths significantly decrease when the phase space reduction is considered for $\\bar{p}$ annihilation products, but they still remain sizeable for potentials consistent with $\\bar{p}$-atom data.

  11. Structural basis for the carbohydrate recognition of the Sclerotium rolfsii lectin.

    Science.gov (United States)

    Leonidas, Demetres D; Swamy, Bale M; Hatzopoulos, George N; Gonchigar, Sathisha J; Chachadi, Vishwanath B; Inamdar, Shashikala R; Zographos, Spyros E; Oikonomakos, Nikos G

    2007-05-11

    The crystal structure of a novel fungal lectin from Sclerotium rolfsii (SRL) in its free form and in complex with N-acetyl-d-galactosamine (GalNAc) and N-acetyl- d -glucosamine (GlcNAc) has been determined at 1.1 A, 2.0 A, and 1.7 A resolution, respectively. The protein structure is composed of two beta-sheets, which consist of four and six beta-strands, connected by two alpha-helices. Sequence and structural comparisons reveal that SRL is the third member of a newly identified family of fungal lectins, which includes lectins from Agaricus bisporus and Xerocomus chrysenteron that share a high degree of structural similarity and carbohydrate specificity. The data for the free SRL are the highest resolution data for any protein of this family. The crystal structures of the SRL in complex with two carbohydrates, GalNAc and GlcNAc, which differ only in the configuration of a single epimeric hydroxyl group, provide the structural basis for its carbohydrate specificity. SRL has two distinct carbohydrate-binding sites, a primary and a secondary. GalNAc binds at the primary site, whereas GlcNAc binds only at the secondary site. Thus, SRL has the ability to recognize and probably bind at the same time two different carbohydrate structures. Structural comparison to Agaricus bisporus lectin-carbohydrate complexes reveals that the primary site is also able to bind the Thomsen-Friedenreich antigen (Galbeta1-->3GalNAc-alpha- glycan structures) whereas the secondary site cannot. The features of the molecular recognition at the two sites are described in detail. PMID:17391699

  12. Minimally refined biomass fuel. [carbohydrate-water-alcohol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.K.; Hirschfeld, T.B.

    1981-03-26

    A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water-solubilizes the carbohydrate; and the alcohol aids in the combustion of the carbohydrate and reduces the viscosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.

  13. Upper bound on the number of steps for solving the subset sum problem by the Branch-and-Bound method

    OpenAIRE

    Kolpakov, Roman; Posypkin, Mikhail

    2015-01-01

    We study the computational complexity of one of the particular cases of the knapsack problem: the subset sum problem. For solving this problem we consider one of the basic variants of the Branch-and-Bound method in which any sub-problem is decomposed along the free variable with the maximal weight. By the complexity of solving a problem by the Branch-and-Bound method we mean the number of steps required for solving the problem by this method. In the paper we obtain upper bounds on the complex...

  14. Carbohydrate recognition by the antiviral lectin cyanovirin-N.

    Science.gov (United States)

    Fujimoto, Yukiji K; Green, David F

    2012-12-01

    Cyanovirin-N (CVN) is a cyanobacterial lectin with potent antiviral activity and has been the focus of extensive preclinical investigation as a potential prophylactic for the prevention of the sexual transmission of the human immunodeficiency virus (HIV). Here we present a detailed analysis of carbohydrate recognition by this important protein, using a combination of computational methods, including extensive molecular dynamics simulations and molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) energetic analysis. The simulation results strongly suggest that the observed tendency of wild-type CVN to form domain-swapped dimers is the result of a previously unidentified cis-peptide bond present in the monomeric state. The energetic analysis additionally indicates that the highest-affinity ligand for CVN characterized to date (α-Man-(1,2)-α-Man-(1,2)-α-Man) is recognized asymmetrically by the two binding sites. Finally, we are able to provide a detailed map of the role of all binding site functional groups (both backbone and side chain) to various aspects of molecular recognition: general affinity for cognate ligands, specificity for distinct oligosaccharide targets, and the asymmetric recognition of α-Man-(1,2)-α-Man-(1,2)-α-Man. Taken as a whole, these results complement past experimental characterization (both structural and thermodynamic) to provide the most complete understanding of carbohydrate recognition by CVN to date. The results also provide strong support for the application of similar approaches to the understanding of other protein-carbohydrate complexes. PMID:23057413

  15. Stability and Sugar Recognition Ability of Ricin-Like Carbohydrate Binding Domains

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Jianzhuang [ORNL; Nellas, Ricky B [ORNL; Glover, Mary M [ORNL; Shen, Tongye [ORNL

    2011-01-01

    Lectins are a class of proteins known for their novel binding to saccharides. Understanding this sugar recognition process can be crucial in creating structure-based designs of proteins with various biological roles. We focus on the sugar binding of a particular lectin, ricin, which has two -trefoil carbohydrate-binding domains (CRDs) found in several plant protein toxins. The binding ability of possible sites of ricin-like CRD has been puzzling. The apo and various (multiple) ligand-bound forms of the sugar-binding domains of ricin were studied by molecular dynamics simulations. By evaluating structural stability, hydrogen bond dynamics, flexibility, and binding energy, we obtained a detailed picture of the sugar recognition of the ricin-like CRD. Unlike what was previously believed, we found that the binding abilities of the two known sites are not independent of each other. The binding ability of one site is positively affected by the other site. While the mean positions of different binding scenarios are not altered significantly, the flexibility of the binding pockets visibly decreases upon multiple ligand binding. This change in flexibility seems to be the origin of the binding cooperativity. All the hydrogen bonds that are strong in the monoligand state are also strong in the double-ligand complex, although the stability is much higher in the latter form due to cooperativity. These strong hydrogen bonds in a monoligand state are deemed to be the essential hydrogen bonds. Furthermore, by examining the structural correlation matrix, the two domains are structurally one entity. Galactose hydroxyl groups, OH4 and OH3, are the most critical parts in both site 1 and site 2 recognition.

  16. Crystallization of carbohydrate oxidase from Microdochium nivale

    Czech Academy of Sciences Publication Activity Database

    Dušková, Jarmila; Dohnálek, Jan; Skálová, Tereza; Ostergaard, L. H.; Fuglsang, C. C.; Kolenko, Petr; Štěpánková, Andrea; Hašek, Jindřich

    2009-01-01

    Roč. 65, č. 6 (2009), s. 638-640. ISSN 1744-3091 R&D Projects: GA AV ČR IAA500500701; GA ČR GA305/07/1073 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbohydrate oxidase * crystallization * data processing Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.551, year: 2009

  17. The diagenesis of carbohydrates by hydrogen sulfide

    Science.gov (United States)

    Mango, Frank D.

    1983-08-01

    Carbohydrates react with hydrogen sulfide under low temperature (100° to 200°C) yielding a variety of organosulfur compounds including thiophenes, thiols, sulfides and sulfones. A polymer is also produced, whose elemental composition is within the range of natural coals. When reductive dehydration is carried out in the presence of hydrocarbon, organosulfur compounds are formed in the carbon number range of the hydrocarbon used. In these processes, an active hydrogen transfer catalyst is produced which facilitates the passage of hydrogen between normal paraffins and saccharide units, distributing sulfur between these two families primarily in the form of thiophene rings. The simplicity of these systems - H 2S, carbohydrates, H 2O, hydrocarbon - and the facility of the chemistry would suggest that the carbohydrates and hydrogen sulfide may be important agents in the diagenetic processes leading to petroleum and coal. Carbohydrate reduction by hydrogen sulfide may constitute an important route through which certain organosulfur compounds found in petroleum and coal entered these materials in early diagenesis.

  18. The clinical impact of carbohydrate malabsorption.

    Science.gov (United States)

    Born, Peter

    2011-03-01

    Malabsorption of carbohydrates such as fructose, lactose or sorbitol can often be detected among patients suffering from so-called non specific abdominal complaints. Sometimes the differential diagnosis may be difficult. So far successful treatment consists of dietary interventions only. Nevertheless, many questions are remaining still unanswered. PMID:21429446

  19. Nutrient and carbohydrate partitioning in sorghum stover

    International Nuclear Information System (INIS)

    Sorghum [Sorghum bicolor (L.) Moench] stover has been demonstrated to be a potential biomass energy source. Complete aboveground crop removal, however, can result in soil degradation. Differential dry matter, nutrient, and carbohydrate partitioning by sorghum cultivars may allow management strategies that return certain parts to the field while removing other portions for alternative uses, such as energy production. A field study was conducted to determine N,P,K, nonstructural carbohydrate, cellulose hemicellulose, and lignin distributions in stover of three diverse sorghum cultivars of differing harvest indices. Determinations were based on total vegetative biomass; total blades; total stalks; and upper middle, and lower blades and stalks. Concentrations of N and P were higher in blades than stalks and generally declines from upper to lower stover parts. Large carbohydrate and lignin concentration differences were observed on the basis of cultivar and stover part. Greater nutrient partitioning to the upper third of the intermediate and forage-type sorghum stovers was observed as compared to the conventional grain cultivar. Stover carbohydrates for all cultivars were mainly contained in the lower two-thirds of the stalk fraction. A system was proposed for returning upper stover portion to soil, while removing remaining portions for alternative uses

  20. General Properties, Occurrence, and Preparation of Carbohydrates

    Science.gov (United States)

    Robyt, John F.

    D-Glucose and its derivatives and analogues, N-acetyl-D-glucosamine, N-acetyl-D-muramic acid, D-glucopyranosyl uronic acid, and D-glucitol represent 99.9% of the carbohydrates on the earth. D-Glucose is found in the free state in human blood and in the combined state in disaccharides, sucrose, lactose, and α,α-trehalose, in cyclic dextrins, and in polysaccharides, starch, glycogen, cellulose, dextrans; N-acetyl-D-glucosamine and an analogue N-acetyl-D-muramic acid are found in bacterial cell wall polysaccharide, murein, along with teichoic acids made up of poly-glycerol or -ribitol phosphodiesters. Other carbohydrates, D-mannose, D-mannuronic acid, D-galactose, N-acetyl-D-galactosamine, D-galacturonic acid, D-iduronic acid, L-guluronic acid, L-rhamnose, L-fucose, D-xylose, and N-acetyl-D-neuraminic acid are found in glycoproteins, hemicelluloses, glycosaminoglycans, and polysaccharides of plant exudates, bacterial capsules, alginates, and heparin. D-Ribofuranose-5-phosphate is found in many coenzymes and is the backbone of RNAs (ribonucleic acid), and 2-deoxy-D-ribofuranose-5-phosphate is the backbone of DNA (deoxyribonucleic acid). D-Fructofuranose is found in sucrose, inulin, and levan. The general properties and occurrence of these carbohydrates and general methods of isolation and preparation of carbohydrates are presented.

  1. Lower Bounds for External Memory Dictionaries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf

    We study trade-offs between the update time and the query time for comparison based external memory dictionaries. The main contributions of this paper are two lower bound trade offs between the I/O complexity of member queries and insertions: If N < M insertions perform at most δ · N/B I/Os, then...... (1) there exists a query requiring N/(M. ·~O(δ)) I/Os, and (2) there exists a query requiring Ω(logδlog2N ~ I/Os when δ is O(B/log3 N) and N is at least M2. For both lower bound we describe data structures which give matching upper bounds for a wide range of parameters, thereby showing the lower...

  2. Bounded link prediction in very large networks

    Science.gov (United States)

    Cui, Wei; Pu, Cunlai; Xu, Zhongqi; Cai, Shimin; Yang, Jian; Michaelson, Andrew

    2016-09-01

    Evaluating link prediction methods is a hard task in very large complex networks due to the prohibitive computational cost. However, if we consider the lower bound of node pairs' similarity scores, this task can be greatly optimized. In this paper, we study CN index in the bounded link prediction framework, which is applicable to enormous heterogeneous networks. Specifically, we propose a fast algorithm based on the parallel computing scheme to obtain all node pairs with CN values larger than the lower bound. Furthermore, we propose a general measurement, called self-predictability, to quantify the performance of similarity indices in link prediction, which can also indicate the link predictability of networks with respect to given similarity indices.

  3. A bound on chaos

    CERN Document Server

    Maldacena, Juan; Stanford, Douglas

    2015-01-01

    We conjecture a sharp bound on the rate of growth of chaos in thermal quantum systems with a large number of degrees of freedom. Chaos can be diagnosed using an out-of-time-order correlation function closely related to the commutator of operators separated in time. We conjecture that the influence of chaos on this correlator can develop no faster than exponentially, with Lyapunov exponent $\\lambda_L \\le 2 \\pi k_B T/\\hbar$. We give a precise mathematical argument, based on plausible physical assumptions, establishing this conjecture.

  4. Regularity of Bound States

    DEFF Research Database (Denmark)

    Faupin, Jeremy; Møller, Jacob Schach; Skibsted, Erik

    2011-01-01

    We study regularity of bound states pertaining to embedded eigenvalues of a self-adjoint operator H, with respect to an auxiliary operator A that is conjugate to H in the sense of Mourre. We work within the framework of singular Mourre theory which enables us to deal with confined massless Pauli......–Fierz models, our primary example, and many-body AC-Stark Hamiltonians. In the simpler context of regular Mourre theory, our results boil down to an improvement of results obtained recently in [8, 9]....

  5. Automatic Complexity Analysis

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    1989-01-01

    One way to analyse programs is to to derive expressions for their computational behaviour. A time bound function (or worst-case complexity) gives an upper bound for the computation time as a function of the size of input. We describe a system to derive such time bounds automatically using abstract...

  6. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Darvill, Alan [Univ. of Georgia, Athens, GA (United States); Hahn, Michael G. [Univ. of Georgia, Athens, GA (United States); O' Neill, Malcolm A. [Univ. of Georgia, Athens, GA (United States); York, William S. [Univ. of Georgia, Athens, GA (United States)

    2015-02-17

    Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

  7. Tight Bernoulli tail probability bounds

    OpenAIRE

    Dzindzalieta, Dainius

    2014-01-01

    The purpose of the dissertation is to prove universal tight bounds for deviation from the mean probability inequalities for functions of random variables. Universal bounds shows that they are uniform with respect to some class of distributions and quantity of variables and other parameters. The bounds are called tight, if we can construct a sequence of random variables, such that the upper bounds are achieved. Such inequalities are useful for example in insurance mathematics, for constructing...

  8. Bounded Rationality in Transposition Processes

    DEFF Research Database (Denmark)

    Vollaard, Hans; Martinsen, Dorte Sindbjerg

    2014-01-01

    concerns the organisation and financing of national healthcare systems. This article applies the perspective of bounded rationality to explain (irregularities in) the timely and correct transposition of EU directives. The cognitive and organisational constraints long posited by the bounded rationality...... bounded rationality is apparent in the transposition processes in these relatively well-organised countries, future transposition studies should devote greater consideration to the bounded rationality perspective....

  9. Novel Bounds on Marginal Probabilities

    OpenAIRE

    Mooij, Joris M.; Kappen, Hilbert J

    2008-01-01

    We derive two related novel bounds on single-variable marginal probability distributions in factor graphs with discrete variables. The first method propagates bounds over a subtree of the factor graph rooted in the variable, and the second method propagates bounds over the self-avoiding walk tree starting at the variable. By construction, both methods not only bound the exact marginal probability distribution of a variable, but also its approximate Belief Propagation marginal (``belief''). Th...

  10. Structure of Dioclea virgata lectin: relations between carbohydrate binding site and nitric oxide production

    Energy Technology Data Exchange (ETDEWEB)

    Delatorre, P.; Gadelha, C.A.A.; Santi-Gadelha, T. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Nobrega, R.B.; Rocha, B.A.M.; Nascimento, K.S.; Naganao, C.S.; Sampaio, A.H.; Cavada, B.S. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Pires, A.F.; Assreuy, A.M.S. [Universidade Estadual do Ceara (UECE), Fortaleza, CE (Brazil)

    2012-07-01

    Full text: Lectins are proteins/glycoproteins with at least one noncatalytic domain binding reversibly to specific monosaccharides or oligosaccharides. By binding to carbohydrate moieties on the cell surface, lectins participate in a range of cellular processes without changing the properties of the carbohydrates involved. The lectin of Dioclea virgata (DvirL), both native and complexed with X-man, was submitted to X-ray diffraction analysis and the crystal structure was compared to that of other Diocleinae lectins in order to better understand differences in biological proper- ties, especially with regard to the ability of lectins to induce nitric oxide (NO) production. The DvirL diffraction analysis revealed that both the native crystal and the X-Man-complexed form are orthorhombic and belong to space group I222. The cell parameters were: a=65.4 , b=86.6 and c=90.2 (native structure), and a=61.89 , b=87.67 and c=88.78 (X-Man-complexed structure). An association was observed between the volume of the carbohydrate recognition domain (CRD), the ability to induce NO production and the relative positions of Tyr12, Arg228 and Leu99. Thus, differences in biological activity induced by Diocleinae lectins are related to the configuration of amino acid residues in the carbohydrate binding site and to the structural conformation of subsequent regions capable of influencing site-ligand interactions. In conclusion, the ability of Diocleinae lectins to induce NO production depends on CRD configuration. (author)

  11. Identification and characterization of sulfated carbohydrate-binding protein from Lactobacillus reuteri.

    Directory of Open Access Journals (Sweden)

    Keita Nishiyama

    Full Text Available We previously purified a putative sulfated-galactosylceramide (sulfatide-binding protein with a molecular weight of 47 kDa from the cell surface of Lactobacillus reuteri JCM1081. The aim of this study was to identify the 47-kDa protein, examine its binding to sulfated glycolipids and mucins, and evaluate its role in bacterial adhesion to mucosal surfaces. By cloning and sequencing analysis, the 47-kDa protein was identified as elongation factor-Tu (EF-Tu. Adhesion properties were examined using 6 × Histidine-fused EF-Tu (His6-EF-Tu. Surface plasmon resonance analysis demonstrated pH-dependent binding of His6-EF-Tu to sulfated glycolipids, but not to neutral or sialylated glycolipids, suggesting that a sulfated galactose residue was responsible for EF-Tu binding. Furthermore, His6-EF-Tu was found to bind to porcine gastric mucin (PGM by enzyme-linked immunosorbent assay. Binding was markedly reduced by sulfatase treatment of PGM and in the presence of acidic and desialylated oligosaccharide fractions containing sulfated carbohydrate residues prepared from PGM, demonstrating that sulfated carbohydrate moieties mediated binding. Histochemical staining revealed similar localization of His6-EF-Tu and high iron diamine staining in porcine mucosa. These results indicated that EF-Tu bound PGM via sulfated carbohydrate moieties. To characterize the contribution of EF-Tu to the interaction between bacterial cells and PGM, we tested whether anti-EF-Tu antibodies could inhibit the interaction. Binding of L. reuteri JCM1081 to PGM was significantly blocked in a concentration-dependent matter, demonstrating the involvement of EF-Tu in bacterial adhesion. In conclusion, the present results demonstrated, for the first time, that EF-Tu bound sulfated carbohydrate moieties of sulfated glycolipids and sulfomucin, thereby promoting adhesion of L. reuteri to mucosal surfaces.

  12. Separable subgroups have bounded packing

    CERN Document Server

    Yang, Wen-yuan

    2010-01-01

    In this note, we prove that separable subgroups have bounded packing in ambient groups. The notion bounded packing was introduced by Hruska-Wise \\cite{HrWi} and in particular, our result confirms a conjecture in \\cite{HrWi} which states each subgroup of a virtually polycyclic group has the bounded packing property.

  13. On bound entanglement assisted distillation

    OpenAIRE

    Vedral, V.

    1999-01-01

    We investigate asymptotic distillation of entanglement in the presence of an unlimited amount of bound entanglement for bi-partite systems. We show that the distillability is still bounded by the relative entropy of entanglement. This offers a strong support to the fact that bound entanglement does not improve distillation of entanglement.

  14. Parallel Branch and Bound Algorithm for Computing Maximal Structured Singular Value

    OpenAIRE

    Chen, Xinjia; Zhou, Kemin

    2008-01-01

    In this paper, we have developed a parallel branch and bound algorithm which computes the maximal structured singular value $\\mu$ without tightly bounding $\\mu$ for each frequency and thus significantly reduce the computational complexity.

  15. Carbohydrate deficient transferrin (CDT) in alcoholic cirrhosis: a kinetic study

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Grønbaek, M; Møller, Søren;

    1997-01-01

    controls (n = 8), which indicates a slow turnover rate of carbohydrate deficient transferrin. Food ingestion did not affect the circulating level of carbohydrate deficient transferrin, and the analysis of carbohydrate deficient transferrin was almost unaffected by the presence of ethanol in plasma within...... alcohol intake, but the overlap is substantial in patients with cirrhosis. Carbohydrate deficient transferrin has a low turnover rate in both patients with cirrhosis and normals....

  16. The carbohydrate-active enzymes database (CAZy) in 2013.

    Science.gov (United States)

    Lombard, Vincent; Golaconda Ramulu, Hemalatha; Drula, Elodie; Coutinho, Pedro M; Henrissat, Bernard

    2014-01-01

    The Carbohydrate-Active Enzymes database (CAZy; http://www.cazy.org) provides online and continuously updated access to a sequence-based family classification linking the sequence to the specificity and 3D structure of the enzymes that assemble, modify and breakdown oligo- and polysaccharides. Functional and 3D structural information is added and curated on a regular basis based on the available literature. In addition to the use of the database by enzymologists seeking curated information on CAZymes, the dissemination of a stable nomenclature for these enzymes is probably a major contribution of CAZy. The past few years have seen the expansion of the CAZy classification scheme to new families, the development of subfamilies in several families and the power of CAZy for the analysis of genomes and metagenomes. This article outlines the changes that have occurred in CAZy during the past 5 years and presents our novel effort to display the resolution and the carbohydrate ligands in crystallographic complexes of CAZymes. PMID:24270786

  17. Strongly Bounded Partial Sums

    Directory of Open Access Journals (Sweden)

    Charles Swartz

    2014-06-01

    Full Text Available If λ is a scalar sequence space, a series P Zj in a topological vector space Z is λ multiplier convergent in Z if the series P ∞J =1 tj Zj converges in Z for every t = {tj} ∈ λ-If λ satisfies appropriate conditions, a series in a locally convex space X which is λ multiplier convergent in the weak topology is λ multiplier convergent in the original topology ofthe space (the Orlicz-Pettis Theorem but may fail to be λ multiplier convergent in the strong topology of the space. However, we show under apprpriate conditions on the multiplier space λ that the series will have strongly bounded partial sums.

  18. Moment Problems on Bounded and Unbounded Domains

    Directory of Open Access Journals (Sweden)

    Octav Olteanu

    2013-01-01

    Full Text Available Using approximation results, we characterize the existence of the solution for a two-dimensional moment problem in the first quadrant, in terms of quadratic forms, similar to the one-dimensional case. For the bounded domain case, one considers a space of complex analytic functions in a disk and a space of continuous functions on a compact interval. The latter result seems to give sufficient (and necessary conditions for the existence of a multiplicative solution.

  19. A sorting network in bounded arithmetic

    Czech Academy of Sciences Publication Activity Database

    Jeřábek, Emil

    2011-01-01

    Roč. 162, č. 4 (2011), s. 341-355. ISSN 0168-0072 R&D Projects: GA AV ČR IAA1019401; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : bounded arithmetic * sorting network * proof complexity * monotone sequent calculus Subject RIV: BA - General Mathematics Impact factor: 0.450, year: 2011 http://www.sciencedirect.com/science/article/pii/S0168007210001272

  20. Carbohydrate plasma expanders for passive tumor targeting

    DEFF Research Database (Denmark)

    Hoffmann, Stefan; Caysa, Henrike; Kuntsche, Judith;

    2013-01-01

    The objective of this study was to investigate the suitability of carbohydrate plasma volume expanders as a novel polymer platform for tumor targeting. Many synthetic polymers have already been synthesized for targeted tumor therapy, but potential advantages of these carbohydrates include...... inexpensive synthesis, constant availability, a good safety profile, biodegradability and the long clinical use as plasma expanders. Three polymers have been tested for cytotoxicity and cytokine activation in cell cultures and conjugated with a near-infrared fluorescent dye: hydroxyethyl starches (HES 200 k......Da and HES 450 kDa) and dextran (DEX 500 kDa). Particle size and molecular weight distribution were determined by asymmetric flow field-flow fractionation (AF4). The biodistribution was investigated non-invasively in nude mice using multispectral optical imaging. The most promising polymer conjugate was...

  1. Fine carbohydrate recognition of Euphorbia milii lectin.

    Science.gov (United States)

    Irazoqui, Fernando J; Vozari-Hampe, Magdolna M; Lardone, Ricardo D; Villarreal, Marcos A; Sendra, Victor G; Montich, Guillermo G; Trindade, Vera M; Clausen, Henrik; Nores, Gustavo A

    2005-10-14

    Glycans are key structures involved in biological processes such as cell attachment, migration, and invasion. Information coded on cell-surface glycans is frequently deciphered by proteins, as lectins, that recognize specific carbohydrate topology. Here, we describe the fine carbohydrate specificity of Euphorbia milii lectin (EML). Competitive assays using various sugars showed that GalNAc was the strongest inhibitor, and that the hydroxyl axial position of C4 and acetamido on C2 of GalNAc are critical points of EML recognition. A hydrophobic locus adjacent to GalNAc is also an important region for EML binding. Direct binding assays of EML revealed a stereochemical requirement for a structure adjacent to terminal GalNAc, showing that GalNAc residue is a necessary but not sufficient condition for EML interaction. The capacity of EML to bind epithelial tumor cells makes it a potentially useful tool for study of some over-expressed GalNAc glycoconjugates. PMID:16122701

  2. Role of carbohydrate metabolism in grass tetany

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.K.; Madsen, F.C.; Lentz, D.E.; Hansard, S.L.

    1977-01-01

    Clinical hypomagnesemia is confined primarily to beef cattle in the United States but also occurs in dairy cattle in other countries, probably due to different management practices. During periods when grass tetany is likely, early vegetative temperate zone grasses are usually low in total readily available carbohydrates and magnesium but high in potassium and nitrogen. The tetany syndrome may include hypoglycemia and ketosis, suggesting an imbalance in intermediary energy metabolism. Many enzyme systems critical to cellular metabolism, including those which hydrolyze and transfer phosphate groups, are activated by Mg. Thus, by inference, Mg is required for normal glucose utilization, fat, protein, nucleic acid and coenzyme synthesis, muscle contraction, methyl group transfer, and sulfate, acetate, and formate activation. Numerous clinical and experimental studies suggest an intimate relationship between metabolism of Mg and that of carbohydrate, glucagon, and insulin. The objective is to review this literature and suggest ways in which these relationships might contribute to a chain of events leading to grass tetany.

  3. A rapid stereoselective synthesis of fluorinated carbohydrates

    International Nuclear Information System (INIS)

    Acetyl hypofluorite has been added to six unsaturated carbohydrates which contain the vinyl ether moiety. All reactions were rapid (less than 5 min.) at -78 degrees C and gave, with one exception, high yields of isomerically pure products. The hypofluorite was shown to add exclusively in a cis mode and with a strong preference for a particular 'face' of the double bond. As well as the syntheses, NMR data and preferred conformations for the fluorinated products are also discussed

  4. Cell surface carbohydrates as prognostic markers in human carcinomas

    DEFF Research Database (Denmark)

    Dabelsteen, Erik

    1996-01-01

    cell types; within a given tissue, variation in expression may be related to cell maturation. Tumour-associated carbohydrate structures often reflect a certain stage of cellular development; most of these moieties are structures normally found in other adult or embryonic tissues. There is no unique......Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core...... tumour carbohydrate structure, since certain structures which are tumour-related in one organ may be normal constituents of other tissues. Tumour-associated carbohydrate changes have been used in the diagnosis of human cancers. Recently, however, it has been demonstrated that the expression of some...

  5. Curve complexes are rigid

    OpenAIRE

    Rafi, Kasra; Schleimer, Saul

    2007-01-01

    Any quasi-isometry of the complex of curves is bounded distance from a simplicial automorphism. As a consequence, the quasi-isometry type of the curve complex determines the homeomorphism type of the surface.

  6. Quantum Communication Complexity

    OpenAIRE

    Klauck, Hartmut

    2000-01-01

    This paper surveys the field of quantum communication complexity. Some interesting recent results are collected concerning relations to classical communication, lower bound methods, one-way communication, and applications of quantum communication complexity.

  7. Quantification of Carbohydrates in Grape Tissues Using Capillary Zone Electrophoresis

    Science.gov (United States)

    Zhao, Lu; Chanon, Ann M.; Chattopadhyay, Nabanita; Dami, Imed E.; Blakeslee, Joshua J.

    2016-01-01

    Soluble sugars play an important role in freezing tolerance in both herbaceous and woody plants, functioning in both the reduction of freezing-induced dehydration and the cryoprotection of cellular constituents. The quantification of soluble sugars in plant tissues is, therefore, essential in understanding freezing tolerance. While a number of analytical techniques and methods have been used to quantify sugars, most of these are expensive and time-consuming due to complex sample preparation procedures which require the derivatization of the carbohydrates being analyzed. Analysis of soluble sugars using capillary zone electrophoresis (CZE) under alkaline conditions with direct UV detection has previously been used to quantify simple sugars in fruit juices. However, it was unclear whether CZE-based methods could be successfully used to quantify the broader range of sugars present in complex plant extracts. Here, we present the development of an optimized CZE method capable of separating and quantifying mono-, di-, and tri-saccharides isolated from plant tissues. This optimized CZE method employs a column electrolyte buffer containing 130 mM NaOH, pH 13.0, creating a current of 185 μA when a separation voltage of 10 kV is employed. The optimized CZE method provides limits-of-detection (an average of 1.5 ng/μL) for individual carbohydrates comparable or superior to those obtained using gas chromatography–mass spectrometry, and allows resolution of non-structural sugars and cell wall components (structural sugars). The optimized CZE method was successfully used to quantify sugars from grape leaves and buds, and is a robust tool for the quantification of plant sugars found in vegetative and woody tissues. The increased analytical efficiency of this CZE method makes it ideal for use in high-throughput metabolomics studies designed to quantify plant sugars. PMID:27379118

  8. Radiation inactivation probe of membrane-bound enzymes: gamma-glutamyltranspeptidase, aminopeptidase N, and sucrase

    International Nuclear Information System (INIS)

    gamma-Glutamyltranspeptidase (GGT), aminopeptidase N (AP-N), and sucrase in purified rabbit intestinal brush border membrane vesicles were irradiated in situ at -135 degrees C using high energy electrons. Surviving activities of the enzymes were measured as a function of radiation dose, and the functional unit target sizes (corresponding to carbohydrate-free polypeptides) were determined using target analysis. The in situ functional unit sizes were GGT 59 kDa, AP-N 59 kDa, and sucrase 63 kDa. Together with biochemical data determined previously, it is concluded that the noncovalently attached large (approximately 40 kDa) and small (approximately 25 kDa) subunits of GGT are both required for catalytic activity. Furthermore, these data suggest that (i) the membrane-bound form of AP-N consists of one or more noncovalently attached subunits of 59 kDa, each of which is enzymatically active; and (ii) in situ sucrase activity is associated with a subunit of 63 kDa which is noncovalently attached within the sucrase-isomaltase complex

  9. Bounding approaches to system identification

    CERN Document Server

    Norton, John; Piet-Lahanier, Hélène; Walter, Éric

    1996-01-01

    In response to the growing interest in bounding error approaches, the editors of this volume offer the first collection of papers to describe advances in techniques and applications of bounding of the parameters, or state variables, of uncertain dynamical systems. Contributors explore the application of the bounding approach as an alternative to the probabilistic analysis of such systems, relating its importance to robust control-system design.

  10. Patterns of organic acids exuded by pioneering fungi from a glacier forefield are affected by carbohydrate sources

    International Nuclear Information System (INIS)

    Bare soils in the area of retreating glaciers are ideal environments to study the role of microorganisms in the early soil formation and in processes of mineral weathering. The aim of our study was to investigate whether the source of carbohydrate would influence the patterns of organic acids exuded by fungal species. Three pioneering fungus species, isolated from fine granitic sediments in front of the Damma glacier from the central Swiss Alps, have previously been found to have the capability to exude organic acids and dissolve granite powder. In batch experiments, various carbohydrates, including glucose, cellulose, pectin, pollen, and cell remnants of cyanobacteria, fungi, and algae, were applied as carbohydrate sources and the patterns of exuded organic acids recorded. The results showed that two fungi, the zygomycete fungus Mucor hiemalis and the ascomycete fungus Penicillium chrysogenum, released a significantly higher amount of organic acids in dependence on specific carbohydrate sources. Pollen and algae as carbohydrate sources triggered significantly the exudation of malate in M. hiemalis, and pollen and cellulose that of oxalate in P. chrysogenum. We conclude that the occurrence of complex carbohydrate sources in nutrient-deficient deglaciated soils may positively influence the exudation of organic acids of fungi. In particular, pollen and remnants of other microorganisms can trigger the exudation of organic acids of fungi in order to promote the weathering of minerals and to make nutrients available that would otherwise be trapped in that cryospheric environment. (paper)

  11. Bounds for Asian basket options

    Science.gov (United States)

    Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle

    2008-09-01

    In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.

  12. A Lower Bound on Concurrence

    Institute of Scientific and Technical Information of China (English)

    LIU Li-Guo; TIAN Cheng-Lin; CHEN Ping-Xing; YUAN Nai-Chang

    2009-01-01

    We derive an analytical lower bound on the concurrence for bipartite quantum systems with an improved computable cross norm or realignment criterion and an improved positive partial transpose criterion respectively.Furthermore we demonstrate that our bound is better than that obtained from the local uncertainty relations criterion with optimal local orthogonal observables which is known as one of the best estimations of concurrence.

  13. Carbohydrates/nucleosides/RNA-DNA-ligand interactions

    Energy Technology Data Exchange (ETDEWEB)

    Kaptein, R.; McConnell, B.; Serianni, A.S.; Silks, L.A. III

    1994-12-01

    Carbohydrate and nucleotide structural determination using modern spectroscopic techniques is dependent on our ability to label oligonucleotides and oligosaccharides with stable isotopes. Uniform Carbon 13 and Nitrogen 15 labeling of oligonucleotides is important to present-day efforts, which are focused on determining the structure of relatively small oligosaccharides and oligonucleotides, which form the elements of larger structures. Because of the relatively recent interest in three-dimensional structure, the development of techniques used to label them has lagged behind parallel techniques used to label peptides and proteins. Therefore, this group`s discussion focused primarily on problems faced today in obtaining oligonucleotides labeled uniformly with carbon 13 and nitrogen 15.

  14. Chapter 22 (Part 3): Carbohydrate Chemistry

    OpenAIRE

    Christiansen, Mike A

    2012-01-01

    In this video I'll continue teaching you about carbohydrate chemistry. I'll teach you how to inter-covert between open- and close-chained forms of monosaccharides, illustrating their pyranose and furanose forms. I also teach you about alpha vs. beta sugars, which are called anomers, and I compare chair conformations with Haworth projections. I'll also teach you how to form glycosides from simple monosaccharides, with the mechanism. I'll introduce you to a few polysaccharides, which include st...

  15. Classical and quantum partition bound and detector inefficiency

    CERN Document Server

    Laplante, S; Roland, J

    2012-01-01

    In communication complexity, two players each have an input and they wish to compute some function of the joint inputs. This has been the object of much study and a wide variety of lower bound methods have been introduced to address the problem of showing lower bounds on communication. Recently, Jain and Klauck introduced the partition bound, which subsumes many of the known methods, in particular factorization norm, discrepancy, and the rectangle (corruption) bound. Physicists have considered a closely related scenario where two players share a predefined entangled state. Each is given a measurement as input, which they perform on their share of the system. The outcomes of the measurements follow a distribution which is predicted by quantum mechanics. In an experimental setting, Bell inequalities are used to distinguish truly quantum from classical behavior. We present a new lower bound technique based on the notion of detector inefficiency (where some runs are discarded by either of the players) for the ext...

  16. A functional genomics approach to establish the complement of carbohydrate transporters in Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Alessandro Bidossi

    Full Text Available The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium:solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection.

  17. A Functional Genomics Approach to Establish the Complement of Carbohydrate Transporters in Streptococcus pneumoniae

    Science.gov (United States)

    Bidossi, Alessandro; Mulas, Laura; Decorosi, Francesca; Colomba, Leonarda; Ricci, Susanna; Pozzi, Gianni; Deutscher, Josef; Viti, Carlo; Oggioni, Marco Rinaldo

    2012-01-01

    The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium∶solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection. PMID:22428019

  18. Effects of carbohydrate, protein and lipid content of organic waste on hydrogen production and fermentation products.

    Science.gov (United States)

    Alibardi, Luca; Cossu, Raffaello

    2016-01-01

    Organic waste from municipalities, food waste and agro-industrial residues are ideal feedstocks for use in biological conversion processes in biorefinery chains, representing biodegradable materials containing a series of substances belonging to the three main groups of the organic matter: carbohydrates, proteins and lipids. Biological hydrogen production by dark fermentation may assume a central role in the biorefinery concept, representing an up-front treatment for organic waste capable of hydrolysing complex organics and producing biohydrogen. This research study was aimed at evaluating the effects of carbohydrate, protein and lipid content of organic waste on hydrogen yields, volatile fatty acid production and carbon-fate. Biogas and hydrogen productions were linearly correlated to carbohydrate content of substrates while proteins and lipids failed to produce significant contributions. Chemical composition also produced effects on the final products of dark fermentation. Acetic and butyric acids were the main fermentation products, with their ratio proving to correlate with carbohydrate and protein content. The results obtained in this research study enhance the understanding of data variability on hydrogen yields from organic waste. Detailed information on waste composition and chemical characterisation are essential to clearly identify the potential performances of the dark fermentation process. PMID:26254676

  19. The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics.

    Science.gov (United States)

    Cantarel, Brandi L; Coutinho, Pedro M; Rancurel, Corinne; Bernard, Thomas; Lombard, Vincent; Henrissat, Bernard

    2009-01-01

    The Carbohydrate-Active Enzyme (CAZy) database is a knowledge-based resource specialized in the enzymes that build and breakdown complex carbohydrates and glycoconjugates. As of September 2008, the database describes the present knowledge on 113 glycoside hydrolase, 91 glycosyltransferase, 19 polysaccharide lyase, 15 carbohydrate esterase and 52 carbohydrate-binding module families. These families are created based on experimentally characterized proteins and are populated by sequences from public databases with significant similarity. Protein biochemical information is continuously curated based on the available literature and structural information. Over 6400 proteins have assigned EC numbers and 700 proteins have a PDB structure. The classification (i) reflects the structural features of these enzymes better than their sole substrate specificity, (ii) helps to reveal the evolutionary relationships between these enzymes and (iii) provides a convenient framework to understand mechanistic properties. This resource has been available for over 10 years to the scientific community, contributing to information dissemination and providing a transversal nomenclature to glycobiologists. More recently, this resource has been used to improve the quality of functional predictions of a number genome projects by providing expert annotation. The CAZy resource resides at URL: http://www.cazy.org/. PMID:18838391

  20. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27041659

  1. Tritium ingestion as organically bound tritium (OBT) - incorporation in different organs of pregnant and non-pregnant rats

    International Nuclear Information System (INIS)

    For a better understanding of the hazard of tritium, its bound form in the food constituents (organically bound tritium (OBT)) has not been investigated though study on tritiated water are many. Hence an evaluation of the uptake of tritium incorporated in basic constituents of food viz, proteins, carbohydrates and lipids is warranted. Present study cells with the incorporated three organically bound tritium components separated from tritiated milk powder (casein, butter and lactose). This is further compared in the organs of pregnant (after parturition) and non-pregnant rats

  2. Bounded link prediction for very large networks

    CERN Document Server

    Cui, Wei; Xu, Zhongqi

    2015-01-01

    Evaluation of link prediction methods is a hard task in very large complex networks because of the inhibitive computational cost. By setting a lower bound of the number of common neighbors (CN), we propose a new framework to efficiently and precisely evaluate the performances of CN-based similarity indices in link prediction for very large heterogeneous networks. Specifically, we propose a fast algorithm based on the parallel computing scheme to obtain all the node pairs with CN values larger than the lower bound. Furthermore, we propose a new measurement, called self-predictability, to quantify the performance of the CN-based similarity indices in link prediction, which on the other side can indicate the link predictability of a network.

  3. Mutual information rate and bounds for it.

    Directory of Open Access Journals (Sweden)

    Murilo S Baptista

    Full Text Available The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR, is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic networks or between two time series (not fully deterministic, and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators.

  4. Mutual information rate and bounds for it.

    Science.gov (United States)

    Baptista, Murilo S; Rubinger, Rero M; Viana, Emilson R; Sartorelli, José C; Parlitz, Ulrich; Grebogi, Celso

    2012-01-01

    The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two time series (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators. PMID:23112809

  5. A Metric Encoding for Bounded Model Checking

    Science.gov (United States)

    Pradella, Matteo; Morzenti, Angelo; San Pietro, Pierluigi

    In Bounded Model Checking, both the system model and the checked property are translated into a Boolean formula to be analyzed by a SAT-solver. We introduce a new encoding technique which is particularly optimized for managing quantitative future and past metric temporal operators, typically found in properties of hard real time systems. The encoding is simple and intuitive in principle, but it is made more complex by the presence, typical of the Bounded Model Checking technique, of backward and forward loops used to represent an ultimately periodic infinite domain by a finite structure. We report and comment on the new encoding technique and on an extensive set of experiments carried out to assess its feasibility and effectiveness.

  6. Carbohydrate synthesis and biosynthesis technologies for cracking of the glycan code: Recent advances

    Czech Academy of Sciences Publication Activity Database

    Mrázek, Hynek; Weignerová, Lenka; Bojarová, Pavla; Novák, Petr; Vaněk, Ondřej; Bezouška, Karel

    2013-01-01

    Roč. 31, č. 1 (2013), s. 17-37. ISSN 0734-9750 R&D Projects: GA ČR GA303/09/0477; GA ČR GD305/09/H008; GA ČR GAP207/10/0321; GA MŠk(CZ) 7E11011; GA MŠk(CZ) LD13041 Institutional support: RVO:61388971 Keywords : Cellular factories * Complex carbohydrates * Glycodrugs Subject RIV: CE - Biochemistry Impact factor: 8.905, year: 2013

  7. A Model for Carbohydrate Metabolism in the Diatom Phaeodactylum tricornutum Deduced from Comparative Whole Genome Analysis

    OpenAIRE

    Kroth, Peter G.; Chiovitti, Anthony; Gruber, Ansgar; Martin-jezequel, Veronique; Mock, Thomas; Schnitzler Parker, Micaela; Michele S. Stanley; Kaplan, Aaron; Caron, Lise; Weber, Till; Maheswari, Uma; Armbrust, Elisabeth Virginia; Bowler, Chris

    2008-01-01

    Background:Diatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids.Methodology/Principal Findings:The whole genome sequence of the diatom Phaeodactylum tricornutum has recently been completed. We identified and annotated genes for enzymes involved in carbohydrate pathways based on extensive EST support and comparison to ...

  8. Metal-Mediated Couplings of Primary Alcohols with Amines and Carbohydrates

    OpenAIRE

    Maggi, Agnese; Madsen, Robert

    2012-01-01

    The work presented in this thesis was performed at the Department of Chemistry of the Technical University of Denmark during a three year Ph.D. program. The thesis involves two distinct Projects related to organometallic and carbohydrate chemistry. Project 1: Dehydrogenative synthesis of imines from alcohols and amines catalyzed by a ruthenium N-heterocyclic carbene complex. The successful method development and application of a convenient and direct (one step) synthesis of imines from alcoho...

  9. Modulation of carbohydrate residues in regenerative nodules and neoplasms of canine and feline pancreas.

    OpenAIRE

    Skutelsky, E.; Alroy, J.; Ucci, A. A.; Carpenter, J.L.; Moore, F. M.

    1987-01-01

    The glycoconjugates of regenerative acinar cells, acinic cell carcinomas, islet cell tumors, and normal canine and feline pancreas were studied. The authors used biotinylated lectins as probes and avidin-biotin-peroxidase complex as visualant to identify and to compare the distribution of carbohydrate residues on paraffin sections from 74 cases. The findings demonstrate a difference in the staining pattern between normal acinar, islet, and ductal cells in each species and small differences in...

  10. Carbohydrate-active enzymes from pigmented Bacilli: a genomic approach to assess carbohydrate utilization and degradation

    Directory of Open Access Journals (Sweden)

    Henrissat Bernard

    2011-09-01

    Full Text Available Abstract Background Spore-forming Bacilli are Gram-positive bacteria commonly found in a variety of natural habitats, including soil, water and the gastro-intestinal (GI-tract of animals. Isolates of various Bacillus species produce pigments, mostly carotenoids, with a putative protective role against UV irradiation and oxygen-reactive forms. Results We report the annotation of carbohydrate active enzymes (CAZymes of two pigmented Bacilli isolated from the human GI-tract and belonging to the Bacillus indicus and B. firmus species. A high number of glycoside hydrolases (GHs and carbohydrate binding modules (CBMs were found in both isolates. A detailed analysis of CAZyme families, was performed and supported by growth data. Carbohydrates able to support growth as the sole carbon source negatively effected carotenoid formation in rich medium, suggesting that a catabolite repression-like mechanism controls carotenoid biosynthesis in both Bacilli. Experimental results on biofilm formation confirmed genomic data on the potentials of B. indicus HU36 to produce a levan-based biofilm, while mucin-binding and -degradation experiments supported genomic data suggesting the ability of both Bacilli to degrade mammalian glycans. Conclusions CAZy analyses of the genomes of the two pigmented Bacilli, compared to other Bacillus species and validated by experimental data on carbohydrate utilization, biofilm formation and mucin degradation, suggests that the two pigmented Bacilli are adapted to the intestinal environment and are suited to grow in and colonize the human gut.

  11. Synthesis and evaluation of novel carbocyclic carbohydrate analogues

    OpenAIRE

    Adamson, Christopher William

    2016-01-01

    Carbohydrate analogues play an indispensible role in the study of glycan processing enzymes. These compounds have attracted attention as probes of enzyme mechanisms, as chemical tools for the elucidation of enzyme function and as potential pharmaceuticals. The development of organocatalytic aldol chemistry has fundamentally altered the way chemists approach the synthesis of carbohydrate analogues. In this thesis I highlight a novel strategy toward the synthesis of carbocyclic carbohydrate ana...

  12. CARBOHYDRATE INGESTION AND EXERCISE: EFFECTS ON METABOLISM AND PERFORMANCE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@KEY POINTS ■ Carbohydrate is the preferred fuel for most competitive sports;an inadequate supply of carbohydrate in the body often leads to poor performance. ■ Carbohydrate ingestion during exercise increases blood glucose availability and maintains the ability of the body to use carbohydrate as fuel during exercise.When carbohydrate is consumed during exercise,glucose uptake by muscles is increased,and the breakdown of glycogen in the liver into blood glucose is reduced,thus saving liver glycogen until late in exercise.The use of muscle glycogen for energy is generally unaffected by carbohydrate feeding.However,during prolonged running,the breakdown of muscle glycogen may be slowed because the supply of blood glucose is improved when carbohydrate is consumed.These metabolic responses underlie the performance benefit that accompanies carbohydrate ingestion during exercise. ■ There are some minor differences among glucose,sucrose,and maltodextrins in their effects on metabolism,but each of them can enhance performance when ingested in the appropriate quantity during exercise.Fructose alone is not an effective carbohydrate supplement because of its slow absorption and slow conversion by the body to glucose,but when small amounts of fructose are combined with other carbohydrates,fructose can be beneficial. ■ Ingesting carbohydrate at a rate of 30-60 grams per hour can improve exercise erformance.A good way to achieve this carbohydrate intake is to consume 600-to-1200 ml(20-to-40 oz)of a sports drink during each hour of exercise.Consuming carbohydrate in a beverage provides an added benefit of preventing potentially harmful effects of dehydration on performance.

  13. Renewable Hydrogen Carrier — Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    Directory of Open Access Journals (Sweden)

    Y.-H. Percival Zhang

    2011-01-01

    Full Text Available The hydrogen economy presents an appealing energy future but its implementation must solve numerous problems ranging from low-cost sustainable production, high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density hydrogen carrier and energy source for hydrogen production is possible due to emerging cell-free synthetic biology technology—cell-free synthetic pathway biotransformation (SyPaB. Assembly of numerous enzymes and co-enzymes in vitro can create complicated set of biological reactions or pathways that microorganisms or catalysts cannot complete, for example, C6H10O5 (aq + 7 H2O (l à 12 H2 (g + 6 CO2 (g (PLoS One 2007, 2:e456. Thanks to 100% selectivity of enzymes, modest reaction conditions, and high-purity of generated hydrogen, carbohydrate is a promising hydrogen carrier for end users. Gravimetric density of carbohydrate is 14.8 H2 mass% if water can be recycled from proton exchange membrane fuel cells or 8.33% H2 mass% without water recycling. Renewable carbohydrate can be isolated from plant biomass or would be produced from a combination of solar electricity/hydrogen and carbon dioxide fixation mediated by high-efficiency artificial photosynthesis mediated by SyPaB. The construction of this carbon-neutral carbohydrate economy would address numerous sustainability challenges, such as electricity and hydrogen storage, CO2 fixation and long-term storage, water conservation, transportation fuel production, plus feed and food production.

  14. CARBOHYDRATE INTAKE CONSIDERATIONS FOR YOUNG ATHLETES

    Directory of Open Access Journals (Sweden)

    Veronica Montfort-Steiger

    2007-09-01

    Full Text Available Good nutritional practices are important for exercise performance and health during all ages. Athletes and especially growing children engaged in heavy training have higher energy and nutrient requirements compared to their non-active counterparts. Scientific understanding of sports nutrition for the young athlete is lacking behind the growing number of young athletes engaged in sports. Most of the sports nutrition recommendations given to athletic children and adolescents are based on adult findings due to the deficiency in age specific information in young athletes. Therefore, this review reflects on child specific sports nutrition, particularly on carbohydrate intake and metabolism that distinguishes the child athlete from the adult athlete. Children are characterised to be in an insulin resistance stage during certain periods of maturation, have different glycolytic/metabolic responses during exercise, have a tendency for higher fat oxidation during exercise and show different heat dissipation mechanisms compared to adults. These features point out that young athletes may need different nutritional advice on carbohydrate for exercise to those from adult athletes. Sport drinks for example may need to be adapted to children specific needs. However, more research in this area is warranted to clarify sports nutrition needs of the young athlete to provide better and healthy nutritional guidance to young athletes

  15. Crystallization of carbohydrate oxidase from Microdochium nivale

    International Nuclear Information System (INIS)

    Industrially used carbohydrate oxidase was successfully crystallized in several forms, diffraction data suitable for structural analysis were collected. Microdochium nivale carbohydrate oxidase was produced by heterologous recombinant expression in Aspergillus oryzae, purified and crystallized. The enzyme crystallizes with varying crystal morphologies depending on the crystallization conditions. Several different crystal forms were obtained using the hanging-drop vapour-diffusion method, two of which were used for diffraction measurements. Hexagon-shaped crystals (form I) diffracted to 2.66 Å resolution, with unit-cell parameters a = b = 55.7, c = 610.4 Å and apparent space group P6222. Analysis of the data quality showed almost perfect twinning of the crystals. Attempts to solve the structure by molecular replacement did not give satisfactory results. Recently, clusters of rod-shaped crystals (form II) were grown in a solution containing PEG MME 550. These crystals belonged to the monoclinic system C2, with unit-cell parameters a = 132.9, b = 56.6, c = 86.5 Å, β = 95.7°. Data sets were collected to a resolution of 2.4 Å. The structure was solved by the molecular-replacement method. Model refinement is currently in progress

  16. Postexercise recovery period: carbohydrate and protein metabolism.

    Science.gov (United States)

    Viru, A

    1996-02-01

    The essence of the postexercise recovery period is normalization of function and homeostatic equilibrium, and replenishment of energy resources and accomplishment of the reconstructive function. The repletion of energy stores is actualized in a certain sequence and followed by a transitory supercompensation. The main substrate for repletion of the muscle glycogen store is blood glucose derived from hepatic glucose output as well as from consumption of carbohydrates during the postexercise period. The repletion of liver glycogen is realized less rapidly. It depends to a certain extent on hepatic gluconeogenesis but mainly on supply with exogenous carbohydrates. The constructive function is founded on elevated protein turnover and adaptive protein synthesis. Whereas during and shortly after endurance exercise intensive protein breakdown was found in less active fast-twitch glycolytic fibers, during the later course of the recovery period the protein degradation rate increased together with intensification of protein synthesis rate in more active fast-twitch glycolytic oxidative and slow-twitch oxidative fibers. PMID:8680938

  17. Quantum computation speedup limits from quantum metrological precision bounds

    OpenAIRE

    Demkowicz-Dobrzanski, Rafal; Markiewicz, Marcin

    2014-01-01

    We propose a scheme for translating metrological precision bounds into lower bounds on query complexity of quantum search algorithms. Within the scheme the link between quadratic performance enhancement in idealized quantum metrological and quantum computing schemes becomes clear. More importantly, we utilize results from the field of quantum metrology on a generic loss of quadratic quantum precision enhancement in presence of decoherence to infer an analogous generic loss of quadratic speed-...

  18. Continuous-Time Stochastic Games with Time-Bounded Reachability

    OpenAIRE

    Brázdil, Tomáš; Forejt, Vojtěch; Krčál, Jan; Křetínský, Jan; Kučera, Antonín

    2013-01-01

    We study continuous-time stochastic games with time-bounded reachability objectives. We show that each vertex in such a game has a emph{value} (i.e., an equilibrium probability), and we classify the conditions under which optimal strategies exist. Finally, we show how to compute optimal strategies in finite uniform games, and how to compute $varepsilon$-optimal strategies in finitely-branching games with bounded rates (for finite games, we provide detailed complexity esti...

  19. New worst upper bound for #SAT

    CERN Document Server

    Zhou, Junping; Zhou, Chunguang

    2010-01-01

    The rigorous theoretical analyses of algorithms for #SAT have been proposed in the literature. As we know, previous algorithms for solving #SAT have been analyzed only regarding the number of variables as the parameter. However, the time complexity for solving #SAT instances depends not only on the number of variables, but also on the number of clauses. Therefore, it is significant to exploit the time complexity from the other point of view, i.e. the number of clauses. In this paper, we present algorithms for solving #2-SAT and #3-SAT with rigorous complexity analyses using the number of clauses as the parameter. By analyzing the algorithms, we obtain the new worst-case upper bounds O(1.1892m) for #2-SAT and O(1.4142m) for #3-SAT, where m is the number of clauses.

  20. Combining Alphas via Bounded Regression

    Directory of Open Access Journals (Sweden)

    Zura Kakushadze

    2015-11-01

    Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

  1. Bounded Model Checking of CTL

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Tao; Cong-Hua Zhou; Zhong Chen; Li-Fu Wang

    2007-01-01

    Bounded Model Checking has been recently introduced as an efficient verification method for reactive systems.This technique reduces model checking of linear temporal logic to propositional satisfiability.In this paper we first present how quantified Boolean decision procedures can replace BDDs.We introduce a bounded model checking procedure for temporal logic CTL* which reduces model checking to the satisfiability of quantified Boolean formulas.Our new technique avoids the space blow up of BDDs, and extends the concept of bounded model checking.

  2. Catalytic Deoxydehydration of Carbohydrates and Polyols to Chemicals and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Kenneth M. [Univ. of Oklahoma, Norman, OK (United States)

    2016-01-15

    As the world's fossil fuel resources are being depleted and their costs increase, there is an urgent need to discover and develop new processes for the conversion of renewable, biomass resources into fuels and chemical feedstocks. Research and development in this area have been given high priority by both governmental agencies and industry. To increase the energy content and decrease the boiling points of biomass-derived carbohydrates and polyols to the useful liquid range it is necessary to chemically remove water (dehydrate) and, preferably, oxygen (deoxygenate/reduce). The poly-hydroxylic nature of carbohydrates is attractive for their use as functionalized chemical building blocks, but it presents a daunting challenge for their selective conversion to single product chemicals or fuels. The long term, practical objective of this project is to develop catalytic processes for the deoxydehydration (DODH) of biomass-derived carbohydrates and polyols to produce unsaturated alcohols and hydrocarbons of value as chemical feedstocks and fuels; DODH: polyol + reductant --(LMOx catalyst)--> unsaturate + oxidized reductant + H2O. Limited prior studies have established the viability of the DODH process with expensive phosphine reductants and rhenium-catalysts. Initial studies in the PI's laboratory have now demonstrated: 1) the moderately efficient conversion of glycols to olefins by the economical sulfite salts is catalyzed by MeReO3 and Z+ReO4-; 2) effective phosphine-based catalytic DODH of representative glycols to olefins by cheap LMoO2 complexes; and 3) computational studies (with K. Houk, UCLA) have identified several Mo-, W-, and V-oxo complexes that are likely to catalyze glycol DODH. Seeking practically useful DODH reactions of complex polyols and new understanding of the reactivity of polyoxo-metal species with biomass-oxygenates we will employ a two-pronged approach: 1) investigate experimentally the reactivity, both stoichiometric and catalytic, of

  3. Quantum Computational Complexity

    OpenAIRE

    Watrous, John

    2008-01-01

    This article surveys quantum computational complexity, with a focus on three fundamental notions: polynomial-time quantum computations, the efficient verification of quantum proofs, and quantum interactive proof systems. Properties of quantum complexity classes based on these notions, such as BQP, QMA, and QIP, are presented. Other topics in quantum complexity, including quantum advice, space-bounded quantum computation, and bounded-depth quantum circuits, are also discussed.

  4. Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

    Directory of Open Access Journals (Sweden)

    Lindsay B. Baker

    2015-07-01

    Full Text Available Intermittent sports (e.g., team sports are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h. Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1 potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2 the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3 what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports. Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before

  5. Cognitive awareness of carbohydrate intake does not alter exercise-induced lymphocyte apoptosis

    OpenAIRE

    James Wilfred Navalta; Brian Keith McFarlin; Scott Lyons; Scott Wesley Arnett; Mark Anthony Schafer

    2011-01-01

    OBJECTIVE: The purpose of this investigation was to determine whether cognitive awareness of carbohydrate beverage consumption affects exercise‐induced lymphocyte apoptosis, independent of actual carbohydrate intake. INTRODUCTION: Carbohydrate supplementation during aerobic exercise generally protects against the immunosuppressive effects of exercise. It is not currently known whether carbohydrate consumption or simply the knowledge of carbohydrate consumption also has that effect. METHODS: E...

  6. Bound states in string nets

    CERN Document Server

    Schulz, M D; Vidal, J

    2016-01-01

    We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.

  7. Global microarray analysis of carbohydrate use in alkaliphilic hemicellulolytic bacterium Bacillus sp. N16-5.

    Directory of Open Access Journals (Sweden)

    Yajian Song

    Full Text Available The alkaliphilic hemicellulolytic bacterium Bacillus sp. N16-5 has a broad substrate spectrum and exhibits the capacity to utilize complex carbohydrates such as galactomannan, xylan, and pectin. In the monosaccharide mixture, sequential utilization by Bacillus sp. N16-5 was observed. Glucose appeared to be its preferential monosaccharide, followed by fructose, mannose, arabinose, xylose, and galactose. Global transcription profiles of the strain were determined separately for growth on six monosaccharides (glucose, fructose, mannose, galactose, arabinose, and xylose and four polysaccharides (galactomannan, xylan, pectin, and sodium carboxymethylcellulose using one-color microarrays. Numerous genes potentially related to polysaccharide degradation, sugar transport, and monosaccharide metabolism were found to respond to a specific substrate. Putative gene clusters for different carbohydrates were identified according to transcriptional patterns and genome annotation. Identification and analysis of these gene clusters contributed to pathway reconstruction for carbohydrate utilization in Bacillus sp. N16-5. Several genes encoding putative sugar transporters were highly expressed during growth on specific sugars, suggesting their functional roles. Two phosphoenolpyruvate-dependent phosphotransferase systems were identified as candidate transporters for mannose and fructose, and a major facilitator superfamily transporter was identified as a candidate transporter for arabinose and xylose. Five carbohydrate uptake transporter 1 family ATP-binding cassette transporters were predicted to participate in the uptake of hemicellulose and pectin degradation products. Collectively, microarray data improved the pathway reconstruction involved in carbohydrate utilization of Bacillus sp. N16-5 and revealed that the organism precisely regulates gene transcription in response to fluctuations in energy resources.

  8. Curvature bounds for configuration spaces

    OpenAIRE

    Erbar, Matthias; Huesmann, Martin

    2014-01-01

    We show that the configuration space over a manifold M inherits many curvature properties of the manifold. For instance, we show that a lower Ricci curvature bound on M implies for the configuration space a lower Ricci curvature bound in the sense of Lott-Sturm-Villani, the Bochner inequality, gradient estimates and Wasserstein contraction. Moreover, we show that the heat flow on the configuration space, or the infinite independent particle process, can be identified as the gradient flow of t...

  9. Entropy bounds for uncollapsed matter

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Gabriel; Visser, Matt, E-mail: Gabriel.Abreu@msor.vuw.ac.nz, E-mail: Matt.Visser@msor.vuw.ac.nz [School of Mathematics, Statistics and Operation Research Victoria University of Wellington Wellington (New Zealand)

    2011-09-22

    In any static spacetime the quasilocal Tolman mass contained within a volume can be reduced to a Gauss-like surface integral involving the flux of a suitably defined generalized surface gravity. By introducing some basic thermodynamics, and invoking the Unruh effect, one can then develop elementary bounds on the quasilocal entropy that are very similar in spirit to the holographic bound, and closely related to entanglement entropy.

  10. Finite Domain Bounds Consistency Revisited

    OpenAIRE

    Choi, Chiu Wo; Harvey, Warwick; Lee, Jimmy Ho-Man; Stuckey, Peter J.

    2004-01-01

    A widely adopted approach to solving constraint satisfaction problems combines systematic tree search with constraint propagation for pruning the search space. Constraint propagation is performed by propagators implementing a certain notion of consistency. Bounds consistency is the method of choice for building propagators for arithmetic constraints and several global constraints in the finite integer domain. However, there has been some confusion in the definition of bounds consistency. In t...

  11. Valuation models and Simon's bounded rationality

    Directory of Open Access Journals (Sweden)

    Alexandra Strommer de Farias Godoi

    2009-09-01

    Full Text Available This paper aims at reconciling the evidence that sophisticated valuation models are increasingly used by companies in their investment appraisal with the literature of bounded rationality, according to which objective optimization is impracticable in the real world because it would demand an immense level of sophistication of the analytical and computational processes of human beings. We show how normative valuation models should rather be viewed as forms of reality representation, frameworks according to which the real world is perceived, fragmented for a better understanding, and recomposed, providing an orderly method for undertaking a task as complex as the investment decision.

  12. Jackson's Theorem on Bounded Symmetric Domains

    Institute of Scientific and Technical Information of China (English)

    Ming Zhi WANG; Guang Bin REN

    2007-01-01

    Polynomial approximation is studied on bounded symmetric domain Ω in C n for holo-morphic function spaces X ,such as Bloch-type spaces,Bergman-type spaces,Hardy spaces,Ω algebra and Lipschitz space.We extend the classical Jackson ’s theorem to several complex variables:E k f,X ) ω (1 /k,f,X ),where E k f,X )is the deviation of the best approximation of f ∈X by polynomials of degree at mostk with respect to the X -metric and ω (1/k,f,X )is the corresponding modulus of continuity.

  13. Topological edge states of bound photon pairs

    CERN Document Server

    Gorlach, Maxim A

    2016-01-01

    We predict the existence of interaction-driven edge states of bound two-photon quasiparticles in a dimer periodic array of nonlinear optical cavities. Energy spectrum of photon pairs is dramatically richer than in the noninteracting case or in a simple lattice, featuring collapse and revival of multiple edge and bulk modes as well as edge states in continuum. Despite the unexpected breakdown of the Zak phase technique and the edge mixing of internal and center-of-mass motion we link the edge state existence to the two-photon quantum walk graph connectivity, thus uncovering the topological nature of the many-body problem in complex lattices.

  14. Tight Bounds for Distributed Functional Monitoring

    CERN Document Server

    Woodruff, David P

    2011-01-01

    We resolve several fundamental questions in the area of distributed functional monitoring, initiated by Cormode, Muthukrishnan, and Yi (SODA, 2008). In this model there are $k$ sites each tracking their input and communicating with a central coordinator that continuously maintain an approximate output to a function $f$ computed over the union of the inputs. The goal is to minimize the communication. We show the randomized communication complexity of estimating the number of distinct elements up to a $1+\\eps$ factor is $\\Omega(k/\\eps^2)$, improving the previous $\\Omega(k + 1/\\eps^2)$ bound and matching known upper bounds. For the $p$-th frequency moment $F_p$, $p > 1$, we improve the previous $\\Omega(k + 1/\\eps^2)$ communication bound to $\\tilde{\\Omega}(k^{p-1}/\\eps^2)$. We obtain similar improvements for heavy hitters, empirical entropy, and other problems. We also show that we can estimate $F_p$, for any $p > 1$, using $\\tilde{O}(k^{p-1}\\poly(\\eps^{-1}))$ communication. This drastically improves upon the pre...

  15. [Determination of the total quantity of carbohydrates in dried yeast].

    Science.gov (United States)

    Maksimenko, O A; Ziukova, L A; Fedorovich, R M

    1975-01-01

    Different colourimetric methods for measuring carbohydrates in yeast have been compared. A method using 5% phenol aqueous solution in the presence of concentrated sulphuric acid has been developed to quantitate carbohydrates. The method has been described as applied to an analysis of dry yeast. PMID:1129224

  16. The role of carbohydrate in dietary prescription for weight loss

    DEFF Research Database (Denmark)

    Astrup, Arne

    to be shown whether a low-glycemic index diet provides benefits beyond this. Low-carbohydrate diets may be an option for inducing weight loss in obese patients, but a very low intake of carbohydrate-rich foods is not commensurate with a healthy and palatable diet in the long term. However, there is...

  17. Why use DFT methods in the study of carbohydrates?

    Science.gov (United States)

    The recent advances in density functional theory (DFT) and computer technology allow us to study systems with more than 100 atoms routinely. This makes it feasible to study large carbohydrate molecules via quantum mechanical methods, whereas in the past, studies of carbohydrates were restricted to ...

  18. Reinforcement effect of soy protein and carbohydrates in polymer composites

    Science.gov (United States)

    The modulus of soft polymer material can be increased by filler reinforcement. A review of using soy protein and carbohydrates as alternative renewable reinforcement material is presented here. Dry soy protein and carbohydrates are rigid and can form strong filler networks through hydrogen-bonding...

  19. Using structure to inform carbohydrate binding module function

    NARCIS (Netherlands)

    Abbott, D. Wade; Lammerts van Bueren, Alicia

    2014-01-01

    Generally, non-catalytic carbohydrate binding module (CBM) specificity has been shown to parallel the catalytic activity of the carbohydrate active enzyme (CAZyme) module it is appended to. With the rapid expansion in metagenomic sequence space for the potential discovery of new CBMs in addition to

  20. Structural and Functional Studies of Peptide-Carbohydrate Mimicry

    Science.gov (United States)

    Johnson, Margaret A.; Pinto, B. Mario

    Certain peptides act as molecular mimics of carbohydrates in that they are specifically recognized by carbohydrate-binding proteins. Peptides that bind to anti-carbohydrate antibodies, carbohydrate-processing enzymes, and lectins have been identified. These peptides are potentially useful as vaccines and therapeutics; for example, immunologically functional peptide molecular mimics (mimotopes) can strengthen or modify immune responses induced by carbohydrate antigens. However, peptides that bind specifically to carbohydrate-binding proteins may not necessarily show the corresponding biological activity, and further selection based on biochemical studies is always required. The degree of structural mimicry required to generate the desired biological activity is therefore an interesting question. This review will discuss recent structural studies of peptide-carbohydrate mimicry employing NMR spectroscopy, X-ray crystallography, and molecular modeling, as well as relevant biochemical data. These studies provide insights into the basis of mimicry at the molecular level. Comparisons with other carbohydrate-mimetic compounds, namely proteins and glycopeptides, will be drawn. Finally, implications for the design of new therapeutic compounds will also be presented.

  1. Carbohydrate loading in the preoperative setting.

    Science.gov (United States)

    Hill, L T; Miller, M G A

    2015-03-01

    Nutrition support is an evolving field, and modern clinical nutrition practice should actively incorporate strategies to enhance various clinical outcomes. In surgical patients, clinical benefits can be maximised by nutritional support protocols that minimise and manage the perioperative fasting period. This approach, which includes the perioperative provision of clear carbohydrate-containing fluids, has been shown to be safe, is evidence based, and is supported by many professional societies. Such a strategy has been shown to aid the anaesthetic process and maintain an optimal metabolic state, including improved insulin sensitivity and blunted muscle catabolic activity. Some important consequences of this improved metabolic control include shorter hospital stay and fewer postoperative complications. A proactive multidisciplinary team approach is essential to use this nutrition support strategy with success across a hospital's surgical service. PMID:26294840

  2. Arabinogalactan proteins: focus on carbohydrate active enzymes

    Directory of Open Access Journals (Sweden)

    Eva eKnoch

    2014-06-01

    Full Text Available Arabinogalactan proteins (AGPs are a highly diverse class of cell surface proteoglycans that are commonly found in most plant species. AGPs play important roles in many cellular processes during plant development, such as reproduction, cell proliferation, pattern formation and growth, and in plant-microbe interaction. However, little is known about the molecular mechanisms of their function. Numerous studies using monoclonal antibodies that recognize different AGP glycan epitopes have shown the appearance of a slightly altered AGP glycan in a specific stage of development in plant cells. Therefore, it is anticipated that the biosynthesis and degradation of AGP glycan is tightly regulated during development. Until recently, however, little was known about the enzymes involved in the metabolism of AGP glycans. In this review, we summarize recent discoveries of carbohydrate active enzymes (CAZy; http://www.cazy.org/ involved in the biosynthesis and degradation of AGP glycans, and we discuss the biological role of these enzymes in plant development.

  3. Reset Complexity of Ideal Languages

    OpenAIRE

    Maslennikova, Marina

    2014-01-01

    We present a new characteristic of a regular ideal language called reset complexity. We find some bounds on the reset complexity in terms of the state complexity of a given language. We also compare the reset complexity and the state complexity for languages related to slowly synchronizing automata and study uniqueness question for automata yielding the minimum of reset complexity.

  4. Structure of a streptococcal adhesion carbohydrate receptor

    International Nuclear Information System (INIS)

    Interactions between complementary protein and carbohydrate structures on different genera of human oral bacteria have been implicated in the formation of dental plaque. The carbohydrate receptor on Streptococcus sanguis H1 that is specific for the adhesion on Capnocytophaga ochracea ATCC 33596 has been isolated from the streptococcal cell wall, purified, and structurally characterized. The hexasaccharide repeating unit of the polysaccharide was purified by reverse-phase, amino-bonded silica, and gel permeation high performance liquid chromatography. Earlier studies established that the repeating unit was a hexasaccharide composed of rhamnose, galactose, and glucose in the ration of 2:3:1, respectively. In the present study, determination of absolute configuration by gas chromatography of the trimethylsilyl (+)-2-butyl glycosides revealed that the rhamnose residues were of the L configuration while the hexoses were all D. 252Californium plasma desorption mass spectrometry of the native, the acetylated and the reduced and acetylated hexasaccharide determined that the molecular mass of the native hexasaccharide was 959, and that the 2 rhamnose residues were linked to each other at the nonreducing terminus of the linear molecule. Methylation analysis revealed the positions of the glycosidic linkages in the hexasaccharide and showed that a galactose residue was present at the reducing end. The structural characterization of the hexasaccharide was completed by one and two dimensional 1H and 13C NMR spectroscopy. Complete 1H and 13C assignments for each glycosyl residue were established by two-dimensional (1H,1H) correlation spectroscopy, homonuclear Hartmann-Hahn, and (13C,1H) correlation experiments. The configurations of the glycosidic linkages were inferred from the chemical shifts and coupling constants of the anomeric 1H and 13C resonances

  5. Sensitive LC MS quantitative analysis of carbohydrates by Cs+ attachment.

    Science.gov (United States)

    Rogatsky, Eduard; Jayatillake, Harsha; Goswami, Gayotri; Tomuta, Vlad; Stein, Daniel

    2005-11-01

    The development of a sensitive assay for the quantitative analysis of carbohydrates from human plasma using LC/MS/MS is described in this paper. After sample preparation, carbohydrates were cationized by Cs(+) after their separation by normal phase liquid chromatography on an amino based column. Cesium is capable of forming a quasi-molecular ion [M + Cs](+) with neutral carbohydrate molecules in the positive ion mode of electrospray ionization mass spectrometry. The mass spectrometer was operated in multiple reaction monitoring mode, and transitions [M + 133] --> 133 were monitored (M, carbohydrate molecular weight). The new method is robust, highly sensitive, rapid, and does not require postcolumn addition or derivatization. It is useful in clinical research for measurement of carbohydrate molecules by isotope dilution assay. PMID:16182559

  6. Mining anaerobic digester consortia metagenomes for secreted carbohydrate active enzymes

    DEFF Research Database (Denmark)

    Wilkens, Casper; Busk, Peter Kamp; Pilgaard, Bo;

    . To gain insight into both the degradation of the carbohydrates and the various roles of the microbes in the ADs we have mined metagenomes from both types of ADs for glycoside hydrolases, carbohydrate esterases, polysaccharide lyases, auxiliary activities, and carbohydrate binding modules. The mining...... thermophilic and mesophilic ADs a wide variety of carbohydrate active enzyme functions were discovered in the metagenomic sequencing of the microbial consortia. The most dominating type of glycoside hydrolases were β-glucosidases (up to 27%), α-amylases (up to 10%), α-glucosidases (up to 8%), α......-galactosidases (up to 9%) and β-galactosidases (up to 7%). For carbohydrate esterases the by far most dominating type was acetylxylan esterases (up to 59%) followed by feruloyl esterases (up to 16%). Less than 15 polysaccharide lyases were identified in the different metagenomes and not surprisingly...

  7. Renewable Hydrogen Carrier — Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    OpenAIRE

    Y.-H. Percival Zhang; Mielenz, Jonathan R.

    2011-01-01

    The hydrogen economy presents an appealing energy future but its implementation must solve numerous problems ranging from low-cost sustainable production, high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density hydrogen carrier and energy source for hydrogen production is possible due to emerging cell-free synthetic biology technology—cell-free synthetic pathway biotransformation (SyPaB). Assembly of numerous enzymes and ...

  8. Renewable Hydrogen Carrier — Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

    OpenAIRE

    Y.-H. Percival Zhang; Mielenz, Jonathan R.

    2011-01-01

    The hydrogen economy presents an appealing energy future but its implementation must solve numerous problems ranging from low-cost sustainable production, high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density hydrogen carrier and energy source for hydrogen production is possible due to emerging cell-free synthetic biology technology–cell-free synthetic pathway biotransformation (SyPaB). Assembly of numerous enzymes and ...

  9. Crystallization and preliminary X-ray analysis of the Ca{sup 2+}-bound C-terminal lobe of troponin C in complex with a troponin I-derived peptide fragment from Akazara scallop

    Energy Technology Data Exchange (ETDEWEB)

    Yumoto, Fumiaki [Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, Bunkyo-ku, Tokyo 113-8657 (Japan); Department of Physiology II, The Jikei University School of Medicine, 3-19-18 Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Nagata, Koji; Miyauchi, Yumiko [Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, Bunkyo-ku, Tokyo 113-8657 (Japan); Ojima, Takao; Tanaka, Hiroyuki; Nishita, Kiyoyoshi [Laboratory of Biochemistry and Biotechnology, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611 (Japan); Ohtsuki, Iwao [Department of Physiology II, The Jikei University School of Medicine, 3-19-18 Nishi-shinbashi, Minato-ku, Tokyo 105-8461 (Japan); Tanokura, Masaru, E-mail: amtanok@mail.ecc.u-tokyo.ac.jp [Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, Bunkyo-ku, Tokyo 113-8657 (Japan)

    2007-06-01

    Recombinant TnC was expressed in Escherichia coli, purified, complexed with a 24-residue synthetic peptide derived from scallop troponin I (TnI) and crystallized. Troponin C (TnC) is the Ca{sup 2+}-binding component of troponin and triggers muscle contraction. TnC of the invertebrate Akazara scallop can bind only one Ca{sup 2+} at the C-terminal EF-hand motif. Recombinant TnC was expressed in Escherichia coli, purified, complexed with a 24-residue synthetic peptide derived from scallop troponin I (TnI) and crystallized. The crystals diffracted X-rays to 1.80 Å resolution and belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 32.1, b = 42.2, c = 60.0 Å. The asymmetric unit was assumed to contain one molecular complex of the Akazara scallop TnC C-lobe and TnI fragment, with a Matthews coefficient of 1.83 Å{sup 3} Da{sup −1} and a solvent content of 33.0%.

  10. Crystallization and preliminary X-ray analysis of the Ca2+-bound C-terminal lobe of troponin C in complex with a troponin I-derived peptide fragment from Akazara scallop

    International Nuclear Information System (INIS)

    Recombinant TnC was expressed in Escherichia coli, purified, complexed with a 24-residue synthetic peptide derived from scallop troponin I (TnI) and crystallized. Troponin C (TnC) is the Ca2+-binding component of troponin and triggers muscle contraction. TnC of the invertebrate Akazara scallop can bind only one Ca2+ at the C-terminal EF-hand motif. Recombinant TnC was expressed in Escherichia coli, purified, complexed with a 24-residue synthetic peptide derived from scallop troponin I (TnI) and crystallized. The crystals diffracted X-rays to 1.80 Å resolution and belonged to space group P212121, with unit-cell parameters a = 32.1, b = 42.2, c = 60.0 Å. The asymmetric unit was assumed to contain one molecular complex of the Akazara scallop TnC C-lobe and TnI fragment, with a Matthews coefficient of 1.83 Å3 Da−1 and a solvent content of 33.0%

  11. On a Generalization of Kingman's Bounds

    OpenAIRE

    Liu, Zhen; Nain, Philippe; Towsley, Don

    1994-01-01

    In this paper we develop a framework for computing upper and lower bounds of an exponential form for a class of single server queueing systems with non-renewal inputs. These bounds generalize Kingman's bounds for queues with renewal inputs.

  12. The case for low carbohydrate diets in diabetes management

    Directory of Open Access Journals (Sweden)

    McFarlane Samy I

    2005-07-01

    Full Text Available Abstract A low fat, high carbohydrate diet in combination with regular exercise is the traditional recommendation for treating diabetes. Compliance with these lifestyle modifications is less than satisfactory, however, and a high carbohydrate diet raises postprandial plasma glucose and insulin secretion, thereby increasing risk of CVD, hypertension, dyslipidemia, obesity and diabetes. Moreover, the current epidemic of diabetes and obesity has been, over the past three decades, accompanied by a significant decrease in fat consumption and an increase in carbohydrate consumption. This apparent failure of the traditional diet, from a public health point of view, indicates that alternative dietary approaches are needed. Because carbohydrate is the major secretagogue of insulin, some form of carbohydrate restriction is a prima facie candidate for dietary control of diabetes. Evidence from various randomized controlled trials in recent years has convinced us that such diets are safe and effective, at least in short-term. These data show low carbohydrate diets to be comparable or better than traditional low fat high carbohydrate diets for weight reduction, improvement in the dyslipidemia of diabetes and metabolic syndrome as well as control of blood pressure, postprandial glycemia and insulin secretion. Furthermore, the ability of low carbohydrate diets to reduce triglycerides and to increase HDL is of particular importance. Resistance to such strategies has been due, in part, to equating it with the popular Atkins diet. However, there are many variations and room for individual physician planning. Some form of low carbohydrate diet, in combination with exercise, is a viable option for patients with diabetes. However, the extreme reduction of carbohydrate of popular diets (

  13. Protein-Carbohydrate Interactions as Part of Plant Defense and Animal Immunity

    Directory of Open Access Journals (Sweden)

    Kristof De Schutter

    2015-05-01

    Full Text Available The immune system consists of a complex network of cells and molecules that interact with each other to initiate the host defense system. Many of these interactions involve specific carbohydrate structures and proteins that specifically recognize and bind them, in particular lectins. It is well established that lectin-carbohydrate interactions play a major role in the immune system, in that they mediate and regulate several interactions that are part of the immune response. Despite obvious differences between the immune system in animals and plants, there are also striking similarities. In both cases, lectins can play a role as pattern recognition receptors, recognizing the pathogens and initiating the stress response. Although plants do not possess an adaptive immune system, they are able to imprint a stress memory, a mechanism in which lectins can be involved. This review will focus on the role of lectins in the immune system of animals and plants.

  14. A central role of abscisic acid in stress-regulated carbohydrate metabolism.

    Directory of Open Access Journals (Sweden)

    Stefan Kempa

    Full Text Available BACKGROUND: Abiotic stresses adversely affect plant growth and development. The hormone abscisic acid (ABA plays a central role in the response and adaptation to environmental constraints. However, apart from the well established role of ABA in regulating gene expression programmes, little is known about its function in plant stress metabolism. PRINCIPAL FINDINGS: Using an integrative multiparallel approach of metabolome and transcriptome analyses, we studied the dynamic response of the model glyophyte Arabidopsis thaliana to ABA and high salt conditions. Our work shows that salt stress induces complex re-adjustment of carbohydrate metabolism and that ABA triggers the initial steps of carbon mobilisation. SIGNIFICANCE: These findings open new perspectives on how high salinity and ABA impact on central carbohydrate metabolism and highlight the power of iterative combinatorial approaches of non-targeted and hypothesis-driven experiments in stress biology.

  15. Glycaemic index of different kinds of carbohydrates in type 2 diabetes.

    Science.gov (United States)

    Donduran, S; Hamulu, F; Cetinkalp, S; Colak, B; Horozoğlu, N; Tüzün, M

    1999-12-01

    An adequate diet provides good metabolic control in diabetics. Since 1981 when Jenkins showed that complex carbohydrates are digested more slowly and raise blood glucose less than simple sugars, many studies have been performed in this field. In this study, seven kinds of carbohydrate-rich food were compared with glucose in 52 Type 2 diabetic patients and 31 normal volunteers. The subject consumed either macaroni, white rice, potatoes, tarhana soup (tarhana includes wheat flour, yoghurt, tomato and green pepper), noodle soup, white or whole wheat bread, or glucose at one-week intervals after an overnight fast. The glycaemic index (GI) of each food was calculated from the area under its glycaemic response curve (AUC) expressed as a percentage of the mean response to glucose. The results showed that the foods ranked from the highest to the lowest GI as follows: white bread; whole wheat bread; macaroni; tarhana soup; white rice; potatoes; noodle soup. PMID:10728183

  16. Dietary non-digestible carbohydrates and the resistance to intestinal infections

    NARCIS (Netherlands)

    Bruggencate, ten S.J.M.

    2004-01-01

    Keywords: Non-digestible carbohydrates, prebiotics, inulin, FOS, calcium, microflora, short-chain fatty acids, mucin, intestinal permeability, salmonella, infection, rat, humanDietary non-digestible carbohydrates and the resistance to intestinal infectionsNon-digestible carbohydrates (NDC) stimulate

  17. Simulation bounds for system availability

    International Nuclear Information System (INIS)

    System availability is a dominant factor in the practicality of nuclear power electrical generating plants. A proposed model for obtaining either lower bounds or interval estimates on availability uses observed data on ''n'' failure-to-repair cycles of the system to estimate the parameters in the time-to-failure and time-to-repair models. These estimates are then used in simulating failure/repair cycles of the system. The availability estimate is obtained for each of 5000 samples of ''n'' failure/repair cycles to form a distribution of estimates. Specific percentile points of those simulated distributions are selected as lower simulation bounds or simulation interval bounds for the system availability. The method is illustrated with operational data from two nuclear plants for which an exponential time-to-failure and a lognormal time-to-repair are assumed

  18. Characterization of Cu(II-ACC Complexes and Conversion of the Bound ACC into Ethylene in the Presence of Hydrogen Peroxide. Detection of a Brown Intermediate at Low Temperature

    Directory of Open Access Journals (Sweden)

    Wadih Ghattas

    2007-01-01

    Full Text Available Two copper(II-ACC complexes were prepared and characterized: [Cu(bpy(ACC(H2O]⋅CO4 (1 and [Cu(ACC2]3⋅4H2O (2. Their crystallographic structures are described and analyzed. Spectroscopic characterizations (UV-visible and EPR confirm that the structure is maintained in solution. These complexes are able to produce ethylene in the presence of hydrogen peroxide in an “ACC Oxidase-like” reaction in water and in methanol. The conversion of ACC into ethylene depends on the amount of base, and, in methanol, 3 equivalents of NaOH are needed for optimum activity. The base is proposed to play a role in H2O2 deprotonation. The presence of an exogenic ligand (bpy is important for the reactivity and may stabilize a reaction intermediate. Indeed, a brown intermediate with an absorption band centered at 433 nm can be detected at low temperature when 1 is treated with 10 equivalents of H2O2.

  19. Refining Castelnuovo-Halphen bounds

    CERN Document Server

    Di Gennaro, Vincenzo

    2011-01-01

    Fix integers $r,d,s,\\pi$ with $r\\geq 4$, $d\\gg s$, $r-1\\leq s \\leq 2r-4$, and $\\pi\\geq 0$. Refining classical results for the genus of a projective curve, we exhibit a sharp upper bound for the arithmetic genus $p_a(C)$ of an integral projective curve $C\\subset {\\mathbb{P}^r}$ of degree $d$, assuming that $C$ is not contained in any surface of degree $ \\pi$. Next we discuss other types of bound for $p_a(C)$, involving conditions on the entire Hilbert polynomial of the integral surfaces on which $C$ may lie.

  20. Bounding solutions of Pfaff equations

    OpenAIRE

    Esteves, E.; Kleiman, S

    2003-01-01

    Let \\omega be a Pfaff system of differential forms on a projective space. Let S be its singular locus, and Y a solution of \\omega=0. We prove Y\\cap S is of codimension at most 1 in Y, just as Jouanolou suspected; he proved this result assuming \\omega is completely integrable, and asked if the integrability is, in fact, needed. Furthermore, we prove a lower bound on the Castelnuovo--Mumford regularity of Y\\cap S. As in two related articles, we derive upper bounds on numerical invariants of Y, ...

  1. Bound orbits and gravitational theory

    OpenAIRE

    Dadhich, Naresh; Ghosh, Sushant G.(School of Mathematical Sciences, University of KwaZulu-Natal, Westville, 4000, Durban, South Africa); Jhingan, Sanjay

    2013-01-01

    It can be easily shown that bound orbits around a static source can exist only in 4 dimension and in none else for any long range force. This is so not only for Maxwell's electromagnetic and Newton's gravity but also for Einstein's gravitation theory. In contrast to Maxwell's electrodynamics and Newton's gravity, GR has a natural higher dimensional generalization in Lovelock gravity which remarkably admits bound orbits around a static black hole in all even d=2N+2 dimensions where $N$ is degr...

  2. Analytic continuation of bound states to solve resonance states

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Norimichi; Arai, Koji [Niigata Univ. (Japan); Suzuki, Yoshiyuki; Varga, K.

    1997-05-01

    As a method to determine the parameters of the resonance state, a method is proposed using analytic continuation on bound constants of correlation. The characteristics of this method consists in probability of prediction of the parameters of the resonance state only by calculation of the bound state. Owing to conducting the analytic continuation on square root of energy in the bound state as a function relating to the bound constant, energy and width in the bound state was determined. Here was reported on a result of application of this method to three systems. Some partial wave on two systems showing correlation at a simple potential and a resonance state of zero of all orbital angular motion quality in three boson system were determined using the analytic continuation method. These results agreed well with one used a method of integrating Schroedinger equation directly and one used the complex scaling method, and this method was found to be much efficient for the study of the resonance state. Under a background of becoming applicable to the method of analytic continuation, there was development of calculating method for the recent small number multi system. As the characteristics of the analytic continuation method is used for only calculation of the bound state, it is convenient at a point applicable to the method to obtain conventional bound state and then is much efficient in a point of applicability of calculus of variations. However, in order to obtain coefficient of Pade approximation correctly, the bound state must be solved correctly, which is difficult for more complex system and is not always applicable to every systems. (G.K.)

  3. Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity

    Science.gov (United States)

    Warda, Alicja K.; Siezen, Roland J.; Boekhorst, Jos; Wells-Bennik, Marjon H. J.; de Jong, Anne; Kuipers, Oscar P.; Nierop Groot, Masja N.; Abee, Tjakko

    2016-01-01

    We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed. PMID:27272929

  4. Contribution of plant carbohydrates to sedimentary carbon mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Vichkovitten, T.; Holmer, M. [University of Southern Denmark, Odense (Denmark). Institute of Biology

    2004-09-01

    The decomposition of different types of organic matter in marine sediments, including eelgrass (Zostera marina) leaves, roots and rhizomes and a macroalga (Polysiphonia spp.), was studied under anoxic conditions using decomposition bags over a period of 24 weeks. The carbohydrate composition of the plant materials and sediment was analyzed using high performance liquid chromatography (HPLC) with pulsed amperometric detection (PAD) and the total sum of individual sugars was taken to represent the total carbohydrate content. The alga was degraded more rapidly than other plant materials, while eelgrass rhizome was recalcitrant to decomposition. The non-structural carbohydrate pool from all plant materials degraded quickly and was gone within the 24-week experiment. A clear reduction in carbohydrate yield for the plant materials provided the most consistent indicator of decomposition status. There was no evident change in carbohydrate amount and composition in the sediment during the decomposition experiments and the non-structural carbohydrates from plant materials were thus more labile and readily available for bacterial decomposition than the bulk of carbohydrates in the sediments. (author)

  5. Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity.

    Directory of Open Access Journals (Sweden)

    Alicja K Warda

    Full Text Available We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed.

  6. Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity.

    Science.gov (United States)

    Warda, Alicja K; Siezen, Roland J; Boekhorst, Jos; Wells-Bennik, Marjon H J; de Jong, Anne; Kuipers, Oscar P; Nierop Groot, Masja N; Abee, Tjakko

    2016-01-01

    We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed. PMID:27272929

  7. Carbohydrate-active enzymes: sequences, shapes, contortions and cells.

    Science.gov (United States)

    Davies, Gideon J; Williams, Spencer J

    2016-02-15

    The enzyme-catalysed degradation of oligo and polysaccharides is of considerable interest in many fields ranging from the fundamental-understanding the intrinsic chemical beauty-through to the applied, including diverse practical applications in medicine and biotechnology. Carbohydrates are the most stereochemically-complex biopolymer, and myriad different natural polysaccharides have led to evolution of multifaceted enzyme consortia for their degradation. The glycosidic bonds that link sugar monomers are among the most chemically-stable, yet enzymatically-labile, bonds in the biosphere. That glycoside hydrolases can achieve a rate enhancement (kcat/kuncat) >10(17)-fold provides testament to their remarkable proficiency and the sophistication of their catalysis reaction mechanisms. The last two decades have seen significant advances in the discovery of new glycosidase sequences, sequence-based classification into families and clans, 3D structures and reaction mechanisms, providing new insights into enzymatic catalysis. New impetus to these studies has been provided by the challenges inherent in plant and microbial polysaccharide degradation, both in the context of environmentally-sustainable routes to foods and biofuels, and increasingly in human nutrition. Study of the reaction mechanism of glycoside hydrolases has also inspired the development of enzyme inhibitors, both as mechanistic probes and increasingly as therapeutic agents. We are on the cusp of a new era where we are learning how to dovetail powerful computational techniques with structural and kinetic data to provide an unprecedented view of conformational details of enzyme action. PMID:26862192

  8. Radiolabeled Peptide Scaffolds for PET/SPECT - Optical in Vivo Imaging of Carbohydrate-Lectin Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Deutscher, Susan

    2014-09-30

    The objective of this research is to develop phage display-selected peptides into radio- and fluoresecently- labeled scaffolds for the multimodal imaging of carbohydrate-lectin interactions. While numerous protein and receptor systems are being explored for the development of targeted imaging agents, the targeting and analysis of carbohydrate-lectin complexes in vivo remains relatively unexplored. Antibodies, nanoparticles, and peptides are being developed that target carbohydrate-lectin complexes in living systems. However, antibodies and nanoparticles often suffer from slow clearance and toxicity problems. Peptides are attractive alternative vehicles for the specific delivery of radionuclides or fluorophores to sites of interest in vivo, although, because of their size, uptake and retention may be less than antibodies. We have selected high affinity peptides that bind a specific carbohydrate-lectin complex involved in cell-cell adhesion and cross-linking using bacteriophage (phage) display technologies (1,2). These peptides have allowed us to probe the role of these antigens in cell adhesion. Fluorescent versions of the peptides have been developed for optical imaging and radiolabeled versions have been used in single photon emission computed tomography (SPECT) and positron emission tomography (PET) in vivo imaging (3-6). A benefit in employing the radiolabeled peptides in SPECT and PET is that these imaging modalities are widely used in living systems and offer deep tissue sensitivity. Radiolabeled peptides, however, often exhibit poor stability and high kidney uptake in vivo. Conversely, optical imaging is sensitive and offers good spatial resolution, but is not useful for deep tissue penetration and is semi-quantitative. Thus, multimodality imaging that relies on the strengths of both radio- and optical- imaging is a current focus for development of new in vivo imaging agents. We propose a novel means to improve the efficacy of radiolabeled and fluorescently

  9. Carbohydrates – Guidelines on Parenteral Nutrition, Chapter 5

    OpenAIRE

    Working group for developing the guidelines for parenteral nutrition of The German Association for Nutritional Medicine; Traeger, K.; Ockenga, J.; Kreymann, G.; Jauch, K.W.; Hauner, H.; Ebener, C.; Bolder, U

    2009-01-01

    The main role of carbohydrates in the human body is to provide energy. Carbohydrates should always be infused with PN (parenteral nutrition) in combination with amino acids and lipid emulsions to improve nitrogen balance. Glucose should be provided as a standard carbohydrate for PN, whereas the use of xylite is not generally recommended. Fructose solutions should not be used for PN. Approximately 60% of non-protein energy should be supplied as glucose with an intake of 3.0–3.5 g/kg body weigh...

  10. Communication Complexity (for Algorithm Designers)

    OpenAIRE

    Roughgarden, Tim

    2015-01-01

    This document collects the lecture notes from my course "Communication Complexity (for Algorithm Designers),'' taught at Stanford in the winter quarter of 2015. The two primary goals of the course are: 1. Learn several canonical problems that have proved the most useful for proving lower bounds (Disjointness, Index, Gap-Hamming, etc.). 2. Learn how to reduce lower bounds for fundamental algorithmic problems to communication complexity lower bounds. Along the way, we'll also: 3. Get exposure t...

  11. Bound states of 'dressed' particles

    International Nuclear Information System (INIS)

    A new approach to the problem of bound states in relativistic quantum field theories is suggested. It uses the creation - destruction operators of 'dresses' particles which have been granted by Faddeev's (1963) 'dressing' formalism. Peculiarities of the proposed approach as compared to the known ones are discussed. 8 refs. (author)

  12. Bounded Densities and Their Derivatives

    DEFF Research Database (Denmark)

    Kozine, Igor; Krymsky, V.

    2009-01-01

    This paper describes how one can compute interval-valued statistical measures given limited information about the underlying distribution. The particular focus is on a bounded derivative of a probability density function and its combination with other available statistical evidence for computing...

  13. Semiclassical bounds in magnetic bottles

    Czech Academy of Sciences Publication Activity Database

    Barseghyan, Diana; Exner, Pavel; Kovařík, H.; Weidl, T.

    2016-01-01

    Roč. 28, č. 1 (2016), s. 1650002. ISSN 0129-055X R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : magnetic Laplacian * discrete spectrum * eigenvalue bounds Subject RIV: BE - Theoretical Physics Impact factor: 1.329, year: 2014

  14. Unconditional lower bounds against advice

    NARCIS (Netherlands)

    H. Buhrman; L. Fortnow; R. Santhanam

    2009-01-01

    We show several unconditional lower bounds for exponential time classes against polynomial time classes with advice, including: (1) For any constant c, NEXP not in P^{NP[n^c]} (2) For any constant c, MAEXP not in MA/n^c (3) BPEXP not in BPP/n^{o(1)}. It was previously unknown even whether NEXP in NP

  15. Bounded Fixed-Point Iteration

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming

    1992-01-01

    In the context of abstract interpretation the authors study the number of times a functional needs to be unfolded in order to give the least fixed point. For the cases of total or monotone functions they obtain an exponential bound and in the case of strict and additive (or distributive) functions...

  16. Market Access through Bound Tariffs

    DEFF Research Database (Denmark)

    Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal

    WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings on t...

  17. Market access through bound tariffs

    DEFF Research Database (Denmark)

    Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal

    2010-01-01

    WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings on t...

  18. Improved Bounds for Geometric Permutations

    CERN Document Server

    Rubin, Natan; Sharir, Micha

    2010-01-01

    We show that the number of geometric permutations of an arbitrary collection of $n$ pairwise disjoint convex sets in $\\mathbb{R}^d$, for $d\\geq 3$, is $O(n^{2d-3}\\log n)$, improving Wenger's 20 years old bound of $O(n^{2d-2})$.

  19. Crystallization of carbohydrate oxidase from Microdochium nivale.

    Science.gov (United States)

    Dusková, Jarmila; Dohnálek, Jan; Skálová, Tereza; Østergaard, Lars Henrik; Fuglsang, Claus Crone; Kolenko, Petr; Stepánková, Andrea; Hasek, Jindrich

    2009-06-01

    Microdochium nivale carbohydrate oxidase was produced by heterologous recombinant expression in Aspergillus oryzae, purified and crystallized. The enzyme crystallizes with varying crystal morphologies depending on the crystallization conditions. Several different crystal forms were obtained using the hanging-drop vapour-diffusion method, two of which were used for diffraction measurements. Hexagon-shaped crystals (form I) diffracted to 2.66 A resolution, with unit-cell parameters a = b = 55.7, c = 610.4 A and apparent space group P6(2)22. Analysis of the data quality showed almost perfect twinning of the crystals. Attempts to solve the structure by molecular replacement did not give satisfactory results. Recently, clusters of rod-shaped crystals (form II) were grown in a solution containing PEG MME 550. These crystals belonged to the monoclinic system C2, with unit-cell parameters a = 132.9, b = 56.6, c = 86.5 A, beta = 95.7 degrees . Data sets were collected to a resolution of 2.4 A. The structure was solved by the molecular-replacement method. Model refinement is currently in progress. PMID:19478452

  20. Carbohydrate degrading polypeptide and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Sagt, Cornelis Maria Jacobus; Schooneveld-Bergmans, Margot Elisabeth Francoise; Roubos, Johannes Andries; Los, Alrik Pieter

    2015-10-20

    The invention relates to a polypeptide having carbohydrate material degrading activity which comprises the amino acid sequence set out in SEQ ID NO: 2 or an amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 1 or SEQ ID NO: 4, or a variant polypeptide or variant polynucleotide thereof, wherein the variant polypeptide has at least 96% sequence identity with the sequence set out in SEQ ID NO: 2 or the variant polynucleotide encodes a polypeptide that has at least 96% sequence identity with the sequence set out in SEQ ID NO: 2. The invention features the full length coding sequence of the novel gene as well as the amino acid sequence of the full-length functional protein and functional equivalents of the gene or the amino acid sequence. The invention also relates to methods for using the polypeptide in industrial processes. Also included in the invention are cells transformed with a polynucleotide according to the invention suitable for producing these proteins.

  1. Application of radiation degraded carbohydrates for plants

    International Nuclear Information System (INIS)

    Radiation degraded carbohydrates such as chitosan, sodium alginate, carageenan, cellulose, pectin, etc. were applied for plant cultivation. Chitosan (poly-β -D-glucosamine) was easily degraded by irradiation and induced various kinds of biological activities such as anti-microbacterial activity, promotion of plant growth, suppression of heavy metal stress on plants, phytoalexins induction, etc. Pectic fragments obtained from degraded pectin also induced the phytoalexins such as glyceollins in soybean and pisafin in pea. The irradiated chitosan shows the higher elicitor activity for pisafin than that of pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. The hot water and ethanol extracts from EFB and sugar cane bagasse were increased by irradiation. These extracts promoted the growth of plants and suppressed the damage on barley with salt and Zn stress. The results show that the degraded polysaccharides by radiation have the potential to induce various biological activities and the products can be use for agricultural and medical fields

  2. Donor substrate recognition in the raffinose-bound E342A mutant of fructosyltransferase Bacillus subtilis levansucrase

    Directory of Open Access Journals (Sweden)

    Meng Guoyu

    2008-03-01

    Full Text Available Abstract Background Fructans – β-D-fructofuranosyl polymers with a sucrose starter unit – constitute a carbohydrate reservoir synthesised by a considerable number of bacteria and plant species. Biosynthesis of levan (αGlc(1–2βFru [(2–6βFru]n, an abundant form of bacterial fructan, is catalysed by levansucrase (sucrose:2,6-β-D-fructan-6-β-D-fructosyl transferase, utilizing sucrose as the sole substrate. Previously, we described the tertiary structure of Bacillus subtilis levansucrase in the ligand-free and sucrose-bound forms, establishing the mechanistic roles of three invariant carboxylate side chains, Asp86, Asp247 and Glu342, which are central to the double displacement reaction mechanism of fructosyl transfer. Still, the structural determinants of the fructosyl transfer reaction thus far have been only partially defined. Results Here, we report high-resolution structures of three levansucrase point mutants, D86A, D247A, and E342A, and that of raffinose-bound levansucrase-E342A. The D86A and D247A substitutions have little effect on the active site geometry. In marked contrast, the E342A mutant reveals conformational flexibility of functionally relevant side chains in the vicinity of the general acid Glu342, including Arg360, a residue required for levan polymerisation. The raffinose-complex reveals a conserved mode of donor substrate binding, involving minimal contacts with the raffinose galactosyl unit, which protrudes out of the active site, and specificity-determining contacts essentially restricted to the sucrosyl moiety. Conclusion The present structures, in conjunction with prior biochemical data, lead us to hypothesise that the conformational flexibility of Arg360 is linked to it forming a transient docking site for the fructosyl-acceptor substrate, through an interaction network involving nearby Glu340 and Asn242 at the rim of a central pocket forming the active site.

  3. Universal Entropy Bound for Rotating Systems

    OpenAIRE

    Hod, Shahar

    1999-01-01

    We conjecture a universal upper bound to the entropy of a rotating system. The entropy bound follows from application of the generalized second law of thermodynamics to an idealized gedanken experiment in which an entropy-bearing rotating system falls into a black hole. This bound is stronger than the Bekenstein entropy bound for non-rotating systems.

  4. Tandem DNA-bound cAMP-CRP complexes are required for transcriptional repression of the deoP2 promoter by the CytR repressor in Escherichia coli

    DEFF Research Database (Denmark)

    Søgaard-Andersen, Lotte; Møllegaard, N E; Douthwaite, S R; Valentin-Hansen, P

    1990-01-01

    We have studied the deoP2 promoter in Escherichia coli to define features important for its interaction with the CytR repressor. As is characteristic for CytR-regulated promoters, deoP2 encodes tandem binding sites for the activating complex cAMP-CRP. One of these sites, CRP-1, overlaps the -35...... region, and is sufficient for activation; the second site, CRP-2, centred around -93, is indispensable for repression. Here we demonstrate, by means of in vivo titration, that CytR interaction with deoP2 depends not only on CRP-2, but also on CRP-1 and the length and possibly the sequence separating...... these two sites. Also, point mutations in either CRP site reduce or abolish CytR titration; however, no co-operativity is observed in the interaction of CytR with the two CRP binding sites. Furthermore, the reduction in CytR titration parallels the reduction in binding of cAMP-CRP to the mutated CRP...

  5. Carbohydrates mediate sperm-ovum adhesion and triggering of the acrosome reaction

    Institute of Scientific and Technical Information of China (English)

    DaulatR.P.Tulsiani

    2000-01-01

    The fertilization process is the net result of a complex sequence of events that collectively result in the fusion of the opposite gametes. The male gamete undergoes continuous morphological and biochemical modifications during sperm development in the testis (spermatogenesis), maturation in the epididymis, and capacitation in the female reproductive tract. Only the capacitated spermatozoa are able to recognize and bind to the bioactive glycan residue(s) on the ovum's extracellular coat, the zona pellucida (ZP). Sperm-zona binding in the mouse and several other species is believed to take place in two stages. First, capacitated (acrosome-intact) spermatozoa loosely and reversibly adhere to the zona-intact ovum. In the second stage tight irreversible binding occurs. Both types of bindings are attributed to the presence of glycan- binding proteins (receptors) on the sperm plasma membrane and their complementary bioactive glycan units (ligands) on the surface of the ZP. The carbohydrate-mediated adhesion event initiates a signal transduction cascade resulting in the exocytosis of acrosomal contents. This step is believed to be prerequisite which allows the hypemctivated acrosome-reacted spermatozoa to penetrate the ZP and fertilize the ovum. This review focuses on the role of carbohydrate residues in sperm-ovum interaction, and triggering of the acrosome reaction. I have attempted to discuss extensive progress that has been made to enhance our understanding of the well programmed multiple molecular events necessary for successful fertilization. This review will identify these events, and discuss the functional significance of carbohydrates in these events.

  6. Amplifying Lower Bounds by Means of Self-Reducibility

    Czech Academy of Sciences Publication Activity Database

    Allender, E.; Koucký, Michal

    Maryland : IEEE Computer Society Press, 2008, s. 31-40. ISBN 978-0-7695-3169-4. [IEEE Conference on Computational Complexity 2008. College Park (US), 23.06.2008-26.06.2008] R&D Projects: GA ČR GP201/07/P276 Institutional research plan: CEZ:AV0Z10190503 Keywords : circuit complexity * lower bounds * natural proofs Subject RIV: BA - General Mathematics

  7. Hydrogen and methane breath tests for evaluation of resistant carbohydrates

    DEFF Research Database (Denmark)

    Rumessen, J J

    1992-01-01

    This review considers in detail the background, principles, techniques, limitations and advantages of the hydrogen and methane breath tests. Resistant food carbohydrates, defined as dietary carbohydrates partly or totally escaping small intestinal assimilation, are fermented in the human colon....... Due to the large interindividual variations of hydrogen excretion, unabsorbable standards should be used. The intraindividual variations of H2 production/excretion and differences in fermentability of different carbohydrate substrates only allow for semiquantitative estimates of malabsorbed amounts of...... some carbohydrates. Methane breath tests may supplement the information gained from hydrogen measurements, but further evaluations are needed. The hydrogen breath technique is rapid, simple and non-invasive as well as non-radioactive. It may be carried out in a large number of intact individuals under...

  8. Synthesis of Heterocylic Compounds of Biological Interest from Carbohydrate Derivatives

    OpenAIRE

    M. F. Martinez Esperón; Fascio, M. L.; N. B. D’Accorso

    2000-01-01

    The synthesis of some isoxazolic compounds from carbohydrate derivatives is described. These products are obtained by 1,3-dipolar cycloaddition reaction and their functionalization leads to derivatives with potential biological activities.

  9. What I Need to Know about Carbohydrate Counting and Diabetes

    Science.gov (United States)

    ... zucchini. Foods that do not contain carbohydrates include meat, fish, and poultry; most types of cheese; nuts; ... Training & Career Development Research at NIDDK Research Resources Technology Advancement & Transfer Meetings & Events Health Information Health Topics ...

  10. Carbohydrate and steroid analysis by desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Kauppila, Tiina J; Talaty, Nari; Jackson, Ayanna U; Kotiaho, Tapio; Kostiainen, Risto; Cooks, R Graham

    2008-06-21

    Desorption electrospray ionization mass spectrometry (DESI-MS) is applied to the analysis of carbohydrates and steroids; the detection limits are significantly improved by the addition of low concentrations of salts to the spray solvent. PMID:18535704

  11. Simple mucin-type carbohydrate antigens in major salivary glands

    DEFF Research Database (Denmark)

    Therkildsen, M H; Mandel, U; Thorn, J; Christensen, M; Dabelsteen, Erik

    1994-01-01

    Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are often markers of neoplastic transformation and have very limited expression in normal tissues. We performed an immunohistological study of simple mucin-type carbohydrate antigens, including H and A variants, with well-defined monoc......Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are often markers of neoplastic transformation and have very limited expression in normal tissues. We performed an immunohistological study of simple mucin-type carbohydrate antigens, including H and A variants, with well...... were predominantly observed in the cell cytoplasm, most often in the supranuclear area, suggesting localization to the Golgi region, whereas ductal contents were unstained. Mucous acinar cells expressed Tn, sialosyl-Tn, and H and A antigens, regardless of glandular location. Serous acinar cells, on the...

  12. Carbohydrate vaccines: developing sweet solutions to sticky situations?

    OpenAIRE

    Astronomo, Rena D.; Burton, Dennis R.

    2010-01-01

    The realm of carbohydrate vaccines has expanded far beyond the capsular polysaccharides of bacterial pathogens to include a diverse collection of targets representing nearly every biological kingdom. Recent technological advances in glycobiology and glycochemistry are paving the way for a new era in carbohydrate vaccine design enabling greater efficiency in the identification, synthesis and evaluation of unique glycan epitopes found on a plethora of pathogens and malignant cells. This article...

  13. Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency

    OpenAIRE

    Anna K. Ciuk; Lindhorst, Thisbe K

    2015-01-01

    Multivalency effects are essential in carbohydrate recognition processes as occurring on the cell surface. Thus many synthetic multivalent glycoconjugates have been developed as important tools for glycobiological research. We are expanding this collection of molecules by the introduction of carbohydrate-scaffolded divalent glycothymine derivatives that can be intramolecularily dimerized by [2 + 2] photocycloaddition. Thus, thymine functions as a control element that allows to restrict the co...

  14. Co-occurrence of carbohydrate malabsorption and primary epiploic appendagitis

    OpenAIRE

    Schnedl, Wolfgang J.; Kalmar, Peter; Mangge, Harald; Krause, Robert; Wallner-Liebmann, Sandra J.

    2015-01-01

    Unspecific abdominal complaints including bloating and irregular bowel movements may be caused by carbohydrate malabsorption syndromes, e.g., lactose and fructose malabsorption. These symptoms were investigated with hydrogen (H2) breath tests and correlated to carbohydrate malabsorption. During performing these H2-breath tests the patient presented with an acute, localized, non-migratory pain in the left lower abdominal quadrant. Primary epiploic appendagitis is a rare cause of abdominal acut...

  15. The case for low carbohydrate diets in diabetes management

    OpenAIRE

    McFarlane Samy I; Arora Surender K

    2005-01-01

    Abstract A low fat, high carbohydrate diet in combination with regular exercise is the traditional recommendation for treating diabetes. Compliance with these lifestyle modifications is less than satisfactory, however, and a high carbohydrate diet raises postprandial plasma glucose and insulin secretion, thereby increasing risk of CVD, hypertension, dyslipidemia, obesity and diabetes. Moreover, the current epidemic of diabetes and obesity has been, over the past three decades, accompanied by ...

  16. Phosphoglucan-bound structure of starch phosphatase Starch Excess4 reveals the mechanism for C6 specificity

    OpenAIRE

    Meekins, David A.; Raththagala, Madushi; Husodo, Satrio; White, Cory J.; Guo, Hou-Fu; Kötting, Oliver; Vander Kooi, Craig W.; Gentry, Matthew S.

    2014-01-01

    Starch is the main carbohydrate storage molecule in plants and is ubiquitous in human life. Reversible starch phosphorylation is the key regulatory event in starch catabolism. Starch Excess4 (SEX4) preferentially dephosphorylates the C6 position of starch glucose and its absence results in a dramatic accumulation of leaf starch. We present the structure of SEX4 bound to a phosphoglucan product, define its mechanism of specific activity, and reverse its specificity to the C3 position via mutag...

  17. Carbohydrate catabolic diversity of bifidobacteria and lactobacilli of human origin.

    Science.gov (United States)

    McLaughlin, Heather P; Motherway, Mary O'Connell; Lakshminarayanan, Bhuvaneswari; Stanton, Catherine; Paul Ross, R; Brulc, Jennifer; Menon, Ravi; O'Toole, Paul W; van Sinderen, Douwe

    2015-06-16

    Because increased proportions of particular commensal bacteria such as bifidobacteria and lactobacilli have been linked to human health through a variety of mechanisms, there is corresponding interest in identifying carbohydrates that promote growth and metabolic activity of these bacteria. We evaluated the ability of 20 carbohydrates, including several commercially available carbohydrates that are sold as prebiotic ingredients, to support growth of 32 human-derived isolates belonging to the genera Bifidobacterium and Lactobacillus, including those isolated from healthy elderly subjects. In general, bifidobacterial strains were shown to display more diverse carbohydrate utilization profiles compared to the tested Lactobacillus species, with several bifidobacterial strains capable of metabolizing xylo-oligosaccharide (XOS), arabinoxylan, maltodextrin, galactan and carbohydrates containing fructo-oligosaccharide (FOS) components. In contrast, maltodextrin, galactan, arabinogalactan and galactomannan did not support robust growth (≥0.8 OD600 nm) of any of the Lactobacillus strains assessed. Carbohydrate fermentation was variable among strains tested of the same species for both genera. This study advances our knowledge of polysaccharide utilization by human gut commensals, and provides information for the rational design of selective prebiotic food ingredients. PMID:25817019

  18. Cause of impaired carbohydrate metabolism in hyperthyroidism

    International Nuclear Information System (INIS)

    Hyperthyroidism (HT) affects glucose metabolism in various ways. The role of insulin, glucagon and growth-hormone (GH) was determined. After glucose loading the insulin response is weaker in HT than in euthyroid subjects. Enhanced degradation of insulin has been reported. It is suggested that in HT the serum insulin concentration declines at a slightly accelerated rate. In HT the deranged carbohydrate metabolism might be a consequence of altered tissue sensitivity to insulin. To elucidate this problem insulin receptors on erythrocytes obtained from hyperthyroid women were investigated. The maximal specific binding of 125I-insulin to RBC of hyperthyroid patients was decreased and the analysis refers to a decreased receptor concentration in RBC. The nature of glucagon secretion and its influence on glucose metabolism in HT was investigated. The basal plasma glucagon is elevated in hyperthyroid patients. The suppression of glucagon secretion induced by an oral glucose loading was of significantly lesser degree in hyperthyroid patients than in controls. Applying the erythrocyte receptor assay a decreased specific binding of 125I-glucagon to RBC of hyperthyroid patients has been found and data indicate a significantly less glucagon receptor concentration in thyrotoxicosis. Physiological elevations of serum GH levels led to a significant impairment of glucose metabolism. Beside the GH-RH and somatostatin, the dopaminergic neurotransmitter system participates in the regulation of GH secretion too. It has been demonstrated that after administration of the dopamine agonist l-dopa the GH response was weaker in HT than in controls. This indicates that in thyrotoxicosis the GH secretion can not be stimulated in such a degree as in euthyroidism. (author)

  19. Carbohydrate Mimetic Peptides Augment Carbohydrate-Reactive Immune Responses in the Absence of Immune Pathology

    Energy Technology Data Exchange (ETDEWEB)

    Hennings, Leah; Artaud, Cecile; Jousheghany, Fariba; Monzavi-Karbassi, Behjatolah; Pashov, Anastas; Kieber-Emmons, Thomas, E-mail: tke@uams.edu [Winthrop P. Rockefeller Cancer Institute and Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States)

    2011-11-11

    Among the most challenging of clinical targets for cancer immunotherapy are Tumor Associated Carbohydrate Antigens (TACAs). To augment immune responses to TACA we are developing carbohydrate mimetic peptides (CMPs) that are sufficiently potent to activate broad-spectrum anti-tumor reactivity. However, the activation of immune responses against terminal mono- and disaccharide constituents of TACA raises concerns regarding the balance between “tumor destruction” and “tissue damage”, as mono- and disaccharides are also expressed on normal tissue. To support the development of CMPs for clinical trial testing, we demonstrate in preclinical safety assessment studies in mice that vaccination with CMPs can enhance responses to TACAs without mediating tissue damage to normal cells expressing TACA. BALB/c mice were immunized with CMPs that mimic TACAs reactive with Griffonia simplicifolia lectin 1 (GS-I), and tissue reactivity of serum antibodies were compared with the tissue staining profile of GS-I. Tissues from CMP immunized mice were analyzed using hematoxylin and eosin stain, and Luxol-fast blue staining for myelination. Western blots of membranes from murine mammary 4T1 cells, syngeneic with BALB/c mice, were also compared using GS-I, immunized serum antibodies, and naive serum antibodies. CMP immunization enhanced glycan reactivities with no evidence of pathological autoimmunity in any immunized mice demonstrating that tissue damage is not an inevitable consequence of TACA reactive responses.

  20. Carbohydrate Mimetic Peptides Augment Carbohydrate-Reactive Immune Responses in the Absence of Immune Pathology

    International Nuclear Information System (INIS)

    Among the most challenging of clinical targets for cancer immunotherapy are Tumor Associated Carbohydrate Antigens (TACAs). To augment immune responses to TACA we are developing carbohydrate mimetic peptides (CMPs) that are sufficiently potent to activate broad-spectrum anti-tumor reactivity. However, the activation of immune responses against terminal mono- and disaccharide constituents of TACA raises concerns regarding the balance between “tumor destruction” and “tissue damage”, as mono- and disaccharides are also expressed on normal tissue. To support the development of CMPs for clinical trial testing, we demonstrate in preclinical safety assessment studies in mice that vaccination with CMPs can enhance responses to TACAs without mediating tissue damage to normal cells expressing TACA. BALB/c mice were immunized with CMPs that mimic TACAs reactive with Griffonia simplicifolia lectin 1 (GS-I), and tissue reactivity of serum antibodies were compared with the tissue staining profile of GS-I. Tissues from CMP immunized mice were analyzed using hematoxylin and eosin stain, and Luxol-fast blue staining for myelination. Western blots of membranes from murine mammary 4T1 cells, syngeneic with BALB/c mice, were also compared using GS-I, immunized serum antibodies, and naive serum antibodies. CMP immunization enhanced glycan reactivities with no evidence of pathological autoimmunity in any immunized mice demonstrating that tissue damage is not an inevitable consequence of TACA reactive responses

  1. ADMonium: Asymmetric Dark Matter Bound State

    CERN Document Server

    Bi, Xiao-Jun; Ko, P; Li, Jinmian; Li, Tianjun

    2016-01-01

    We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. Therefore, the ADM can form bound state due to its large self-interaction via $X$ mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with $b\\bar b$. Of particular interest, our setup nicely explains the recent di-photon anomaly at 750 GeV via the events from ${\\rm ADMonium}\\ra 2X(\\ra e^+e^-)$, where the electrons are identified as ...

  2. Generalized bounds for convex multistage stochastic programs

    CERN Document Server

    Künzi, H; Fandel, G; Trockel, W; Basile, A; Drexl, A; Dawid, H; Inderfurth, K; Kürsten, W; Schittko, U

    2005-01-01

    This work was completed during my tenure as a scientific assistant and d- toral student at the Institute for Operations Research at the University of St. Gallen. During that time, I was involved in several industry projects in the field of power management, on the occasion of which I was repeatedly c- fronted with complex decision problems under uncertainty. Although usually hard to solve, I quickly learned to appreciate the benefit of stochastic progr- ming models and developed a strong interest in their theoretical properties. Motivated both by practical questions and theoretical concerns, I became p- ticularly interested in the art of finding tight bounds on the optimal value of a given model. The present work attempts to make a contribution to this important branch of stochastic optimization theory. In particular, it aims at extending some classical bounding methods to broader problem classes of practical relevance. This book was accepted as a doctoral thesis by the University of St. Gallen in June 2004.1...

  3. Physics with loosely bound nuclei

    Indian Academy of Sciences (India)

    Chhanda Samanta

    2001-08-01

    The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to find a consistent picture for the unstable nuclei starting from their stable counterparts. Some significant differences in the structure and reaction mechanisms are found.

  4. Concentration Bounds for Stochastic Approximations

    CERN Document Server

    Frikha, Noufel

    2012-01-01

    We obtain non asymptotic concentration bounds for two kinds of stochastic approximations. We first consider the deviations between the expectation of a given function of the Euler scheme of some diffusion process at a fixed deterministic time and its empirical mean obtained by the Monte-Carlo procedure. We then give some estimates concerning the deviation between the value at a given time-step of a stochastic approximation algorithm and its target. Under suitable assumptions both concentration bounds turn out to be Gaussian. The key tool consists in exploiting accurately the concentration properties of the increments of the schemes. For the first case, as opposed to the previous work of Lemaire and Menozzi (EJP, 2010), we do not have any systematic bias in our estimates. Also, no specific non-degeneracy conditions are assumed.

  5. Assessing the Impacts of Low Carbohydrate Related Health Information on the Market Demand for US Vegetables

    OpenAIRE

    Paudel, Laxmi; Adhikari, Murali; Houston, Jack E.

    2005-01-01

    An Almost Ideal Demand System was estimated to examine the impacts of low carbohydrate information on the market demand for US vegetables. Analysis was extended to examine the performance of alternative carbohydrate information indexes. Study shows significant robust impacts of low carbohydrate information across all included vegetables. Results favor the general and weighted carbohydrate information index.

  6. Bound anionic states of adenine

    OpenAIRE

    Harańczyk, Maciej; Gutowski, Maciej; Li, Xiang; Bowen, Kit H.

    2007-01-01

    Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine...

  7. The bound mu+ mu- system

    OpenAIRE

    Jentschura, U.; Soff, G.; Ivanov, V.; Karshenboim, S.

    1997-01-01

    We consider the hyperfine structure, the atomic spectrum and the decay channels of the bound mu+ mu- system (dimuonium). The annihilation lifetimes of low-lying atomic states of the system lie in the nanosecond range range. The decay rates could be measured by detection of the decay products (high energy photons or electron-positron pairs). The hyperfine structure splitting of the dimuonic system and its decay rate are influenced by electronic vacuum polarization effects in the far time-like ...

  8. Provably Bounded-Optimal Agents

    OpenAIRE

    Russell, S J; Subramanian, D.

    1995-01-01

    Since its inception, artificial intelligence has relied upon a theoretical foundation centered around perfect rationality as the desired property of intelligent systems. We argue, as others have done, that this foundation is inadequate because it imposes fundamentally unsatisfiable requirements. As a result, there has arisen a wide gap between theory and practice in AI, hindering progress in the field. We propose instead a property called bounded optimality. Roughly speaking, an agent is boun...

  9. 78 FR 18326 - Agency Information Collection Activities; Comment Request; Upward Bound and Upward Bound Math...

    Science.gov (United States)

    2013-03-26

    ... Agency Information Collection Activities; Comment Request; Upward Bound and Upward Bound Math Science... Upward Bound Math Science Annual Performance Report. OMB Control Number: 1840-NEW. Type of Review: New... under the regular Upward Bound (UB) and Upward Bound Math and Science (UBMS) Programs. The Department...

  10. The Cost of Bounded Curvature

    CERN Document Server

    Kim, Hyo-Sil

    2011-01-01

    We study the motion-planning problem for a car-like robot whose turning radius is bounded from below by one and which is allowed to move in the forward direction only (Dubins car). For two robot configurations $\\sigma, \\sigma'$, let $\\ell(\\sigma, \\sigma')$ be the shortest bounded-curvature path from $\\sigma$ to $\\sigma'$. For $d \\geq 0$, let $\\ell(d)$ be the supremum of $\\ell(\\sigma, \\sigma')$, over all pairs $(\\sigma, \\sigma')$ that are at Euclidean distance $d$. We study the function $\\dub(d) = \\ell(d) - d$, which expresses the difference between the bounded-curvature path length and the Euclidean distance of its endpoints. We show that $\\dub(d)$ decreases monotonically from $\\dub(0) = 7\\pi/3$ to $\\dub(\\ds) = 2\\pi$, and is constant for $d \\geq \\ds$. Here $\\ds \\approx 1.5874$. We describe pairs of configurations that exhibit the worst-case of $\\dub(d)$ for every distance $d$.

  11. Modified carbohydrate-chitosan compounds, methods of making the same and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, Richard A; Pawlak, Joel J; Salam, Abdus; El-Tahlawy, Khaled Fathy

    2015-03-10

    Compositions of matter are provided that include chitosan and a modified carbohydrate. The modified carbohydrate includes a carbohydrate component and a cross linking agent. The modified carbohydrate has increased carboxyl content as compared to an unmodified counterpart carbohydrate. A carboxyl group of the modified carbohydrate is covalently bonded with an amino group of chitosan. The compositions of matter provided herein may include cross linked starch citrate-chitosan and cross linked hemicellulose citrate-chitosan, including foams thereof. These compositions yield excellent absorbency and metal chelation properties. Methods of making cross linked modified carbohydrate-chitosan compounds are also provided.

  12. A semidefinite programming based branch-and-bound framework for the quadratic assignment problem

    OpenAIRE

    2014-01-01

    The practical approach to calculate an exact solution for a quadratic assignment problem (QAP) via a branch-and-bound framework depends strongly on a "smart" choice of different strategies within the framework, for example the branching strategy, heuristics for the upper bound or relaxations for the lower bound. In the first part of this thesis, we analyze promising old and new semidefinite programming (SDP) relaxations. In particular, we focus on their complexity, the strength of the respect...

  13. Causal Entropy Bound for a Spacelike Region

    Science.gov (United States)

    Brustein, R.; Veneziano, G.

    2000-06-01

    The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic spacelike region. This ``causal entropy bound,'' scaling as EV, and thus lying around the geometric mean of Bekenstein's S/ER and holographic S/A bounds, is checked in various ``critical'' situations. In the case of limited gravity, Bekenstein's bound is the strongest while naive holography is the weakest. In the case of strong gravity, our bound and Bousso's holographic bound are stronger than Bekenstein's, while naive holography is too tight, and hence typically wrong.

  14. Competition analysis of a triopoly game with bounded rationality

    International Nuclear Information System (INIS)

    Highlights: ► We model a Cournot triopoly game with three boundedly rational players. ► The equilibrium points of the model and their local stability are investigated. ► We study the dynamics of this model as varying the parameters. ► The stability of Nash equilibrium is lost and a chaotic behaviors occur. - Abstract: A dynamic Cournot game characterized by three boundedly rational players is modeled by three nonlinear difference equations. The stability of the equilibria of the discrete dynamical system is analyzed. As some parameters of the model are varied, the stability of Nash equilibrium is lost and a complex chaotic behavior occurs. Numerical simulation results show that complex dynamics, such as, bifurcations and chaos are displayed when the value of speed of adjustment is high. The global complexity analysis can help players to take some measures and avoid the collapse of the output dynamic competition game.

  15. Bounding the Set of Finite Dimensional Quantum Correlations.

    Science.gov (United States)

    Navascués, Miguel; Vértesi, Tamás

    2015-07-10

    We describe a simple method to derive high performance semidefinite programing relaxations for optimizations over complex and real operator algebras in finite dimensional Hilbert spaces. The method is very flexible, easy to program, and allows the user to assess the behavior of finite dimensional quantum systems in a number of interesting setups. We use this method to bound the strength of quantum nonlocality in Bell scenarios where the dimension of the parties is bounded from above. We derive new results in quantum communication complexity and prove the soundness of the prepare-and-measure dimension witnesses introduced in Gallego et al., Phys. Rev. Lett. 105, 230501 (2010). Finally, we propose a new dimension witness that can distinguish between classical, real, and complex two-level systems. PMID:26207454

  16. 2009 Cellulosomes, Cellulases & Other Carbohydrate Modifying Enzymes GRC

    Energy Technology Data Exchange (ETDEWEB)

    Harry Gilbert

    2009-07-26

    The 2009 Gordon Conference on Cellulosomes, Cellulases & Other Carbohydrate Modifying Enzymes will present cutting-edge research on the enzymatic degradation of cellulose and other plant cell wall polysaccharides. The Conference will feature a wide range of topics that includes the enzymology of plant structural degradation, regulation of the degradative apparatus, the mechanism of protein complex assembly, the genomics of cell wall degrading organisms, the structure of the substrate and the industrial application of the process particularly within the biofuel arena. Indeed the deployment of plant cell wall degrading enzymes in biofuel processes will be an important feature of the meeting. It should be emphasized that the 2009 Conference will be expanded to include, in addition to cellulase research, recent advances in other plant cell wall degrading enzymes, and contributions from people working on hemicellulases and pectinases will be particularly welcome. Invited speakers represent a variety of scientific disciplines, including biochemistry, structural biology, genetics and cell biology. The interplay between fundamental research and its industrial exploitation is a particularly important aspect of the meeting, reflecting the appointment of the chair and vice-chair from academia and industry, respectively. The meeting will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with more established figures in the field. Indeed, some poster presenters will be selected for short talks. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented. The Conference is likely to be heavily subscribed so we would recommend that you submit

  17. Data Structure Lower Bounds on Random Access to Grammar-Compressed Strings

    DEFF Research Database (Denmark)

    Chen, Shiteng; Verbin, Elad; Yu, Wei

    2012-01-01

    proof works by reduction to communication complexity, namely to the LSD problem, recently employed by Patrascu and others. We prove lower bounds also for the case of LZ-compression and Burrows-Wheeler (BWT) compression. All of our lower bounds hold even when the strings are over an alphabet of size 2...

  18. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    DEFF Research Database (Denmark)

    Wong, Jaslyn E M M; Midtgaard, Søren Roi; Gysel, Kira; Thygesen, Mikkel B; Sørensen, Kasper K; Jensen, Knud J; Stougaard, Jens; Thirup, Søren; Blaise, Mickaël

    multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering...

  19. Extension of Drosophila Lifespan by Rhodiola rosea Depends on Dietary Carbohydrate and Caloric Content in a Simplified Diet.

    Science.gov (United States)

    Schriner, Samuel E; Coskun, Volkan; Hogan, Sean P; Nguyen, Cindy T; Lopez, Terry E; Jafari, Mahtab

    2016-03-01

    The root and rhizome extract of Rhodiola rosea has been extensively used in traditional medicine to improve physical and mental performance and to protect against stress. We, and others, have reported that R. rosea can extend lifespan in flies, worms, and yeast. We also previously found that the extract can act independently of dietary restriction (DR), a treatment that can extend lifespan in a range of model organisms. In flies, DR is implemented through a reduction in dietary yeast content. Here, we report that the ability of R. rosea extract to extend lifespan in flies is dependent on the carbohydrate and caloric content when supplemented with a simplified diet composed of yeast and sucrose. R. rosea extract elevated the sugar content in flies and down-regulated hexokinase expression, suggesting that it perturbs carbohydrate metabolism in flies. In our previous studies, bananas, barley malt, and corn syrup provided dietary carbohydrates, and R. rosea extract could extend lifespan with a range of caloric levels. We conclude that the lifespan-extending effect of R. rosea extract in flies is dependent on dietary carbohydrate and caloric contents coupled with an interaction with complex dietary components present in bananas, barley, or corn. PMID:26987024

  20. Synthesis and emulsifying properties of carbohydrate fatty acid esters produced from Agave tequilana fructans by enzymatic acylation.

    Science.gov (United States)

    Casas-Godoy, Leticia; Arrizon, Javier; Arrieta-Baez, Daniel; Plou, Francisco J; Sandoval, Georgina

    2016-08-01

    Carbohydrate fatty acid esters are non-ionic surfactants with a broad spectrum of applications. These molecules are generally synthesized using short carbohydrates or linear fructans; however in this research carbohydrate fatty acid esters were produced for the first time with branched fructans from Agave tequilana. Using immobilized lipases we successfully acylated A. tequilana fructans with vinyl laurate, obtaining products with different degrees of polymerization (DP). Lipozyme 435 was the most efficient lipase to catalyze the transesterification reaction. HPLC and ESI-MS analysis proved the presence of a mixture of acylated products as a result of the chemical complexity of fructans in the A. tequilana. The ESI-MS spectra showed a molecular mass shift between 183 and 366g/mol for fructooligosaccharides with a DP lower than 6, which indicated the presence of Agave fructans that had been mono- and diacylated with lauric acid. The carbohydrate fatty acid esters (CFAE) obtained showed good emulsifying properties in W/O emulsions. PMID:26988522

  1. Fast carbohydrate analysis via liquid chromatography coupled with ultra violet and electrospray ionization ion trap detection in 96-well format.

    Science.gov (United States)

    Rühmann, Broder; Schmid, Jochen; Sieber, Volker

    2014-07-11

    A fast carbohydrate screening platform processible in 96-well format is described. The method is suitable for the determination of various carbohydrates out of complex mixtures as obtained by acidic hydrolysis of carbohydrates polymers. The chromatographic conditions for an efficient separation (12min) and the derivatization process with 1-phenyl-3-methyl-5-pyrazolone (PMP) were optimized for high resolution separation and simultaneous determination of deoxy-, amino-, anhydro-sugars as well as hexoses, pentoses, dimers, uronic acids and degradation products like furfural and hydroxymethylfurfural (HMF). The potential to quantify with UV- and MS-detector in the same range has been demonstrated for 20 different compounds. Finally, the matrix effects of the hydrolysis were positively evaluated. The micro scale hydrolysis and PMP-derivatization without any extraction or drying steps, both in 96-well format, result in a fast and intuitive sample preparation. In combination with a fast liquid chromatography coupled to UV and electrospray ionization ion trap detection (LC-UV-ESI-MS/MS) for the qualification and quantification of various sugars, dimers and degradation products, this method shows great performance in carbohydrate analysis. PMID:24861788

  2. Effect of carbohydrate restriction and high carbohydrates diets on men with chemical diabetes.

    Science.gov (United States)

    Anderson, J W

    1977-03-01

    The influence of low carbohydrate (CHO) diets, starvation, and high CHO diets on glucose tolerance tests (GTT) and plasma insulin response of men with chemical diabetes was studied. The GTT and insulin responses of these seven lean diabetic men were unchanged when the carbohydrate content of the diet was reduced from 44 to 20% of calories. After a 48-hr fast a significant deterioration of the GTT was observed in these diabetic men but the percentage change was identical to that reported previously for normal men. Thus these studies indicate that changes in glucose mtes are quite similar to those reported previously for normal men. The fasting plasma glucose values of seven lean and four obese men with chemical diabetes were significantly lower after one week on a 75% CHO diet than values on a 44% CHO diet. The 75% CHO diet also was accompanied by slight improvements in the oral and intravenous GTT and by slightly lower plasma insulin responses. The improvement in glucose metabolism on high CHO diets appears to results from increased insulin sensitivity. Serum triglyceride values were approximately 55% higher on the 75% CHO diet than values on the 44% CHO diet for the 11 men but these differences were not statistically significant. These studies support previous observations and suggest that high CHO diets may be beneficial in the management of certain diabetic patients. However, further studies are required to determine the long-term effects of high CHO diets containing natural foods on the glucose and lipid metabolism of diabetic patients. PMID:842491

  3. Relativistic bound state approach to fundamental forces including gravitation

    Directory of Open Access Journals (Sweden)

    Morsch H.P.

    2012-06-01

    Full Text Available To describe the structure of particle bound states of nature, a relativistic bound state formalism is presented, which requires a Lagrangian including scalar coupling of two boson fields. The underlying mechanisms are quite complex and require an interplay of overlapping boson fields and fermion-antifermion production. This gives rise to two potentials, a boson-exchange potential and one identified with the long sought confinement potential in hadrons. With minimal requirements, two elementary massless fermions (quantons - with and without charge - and one gauge boson, hadrons and leptons but also atoms and gravitational systems are described by bound states with electric and magnetic coupling between the charges and spins of quantons. No need is found for colour, Higgs-coupling and supersymmetry.

  4. On Some Properties of Squeezing Functions of Bounded Domains

    CERN Document Server

    Deng, Fusheng; Zhang, Liyou

    2011-01-01

    The main purpose of the present paper is to introduce the notion of squeezing functions of bounded domains and study some properties of them. The relation to geometric and analytic structures of bounded domains will be investigated. Existence of related extremal maps and continuity of squeezing functions are proved. Holomorphic homogeneous regular domains are exactly domains whose squeezing functions have positive lower bounds. Completeness of certain intrinsic metrics and pseudoconvexity of holomorphic homogeneous regular domains are proved by alternative method. In dimension one case, we get a neat description of boundary behavior of squeezing functions of finitely connected planar domains. This leads to a necessary and sufficient conditions for a finitely connected planar domain to be a holomorphic homogeneous regular domain. Consequently, we can recover some important results in complex analysis. For annuli, we obtain some interesting properties of their squeezing functions. We finally exhibit some exampl...

  5. Conformational entropy changes upon lactose binding to the carbohydrate recognition domain of galectin-3

    International Nuclear Information System (INIS)

    The conformational entropy of proteins can make significant contributions to the free energy of ligand binding. NMR spin relaxation enables site-specific investigation of conformational entropy, via order parameters that parameterize local reorientational fluctuations of rank-2 tensors. Here we have probed the conformational entropy of lactose binding to the carbohydrate recognition domain of galectin-3 (Gal3), a protein that plays an important role in cell growth, cell differentiation, cell cycle regulation, and apoptosis, making it a potential target for therapeutic intervention in inflammation and cancer. We used 15N spin relaxation experiments and molecular dynamics simulations to monitor the backbone amides and secondary amines of the tryptophan and arginine side chains in the ligand-free and lactose-bound states of Gal3. Overall, we observe good agreement between the experimental and computed order parameters of the ligand-free and lactose-bound states. Thus, the 15N spin relaxation data indicate that the molecular dynamics simulations provide reliable information on the conformational entropy of the binding process. The molecular dynamics simulations reveal a correlation between the simulated order parameters and residue-specific backbone entropy, re-emphasizing that order parameters provide useful estimates of local conformational entropy. The present results show that the protein backbone exhibits an increase in conformational entropy upon binding lactose, without any accompanying structural changes

  6. Changes in carbohydrate expression in the cervical spinal cord of rats during aging.

    Science.gov (United States)

    Lozza, Facundo A; Chinchilla, Leonardo A; Barbeito, Claudio G; Goya, Rodolfo G; Gimeno, Eduardo J; Portiansky, Enrique L

    2009-06-01

    Aging is a process where histochemical changes occur. Some of these may consist of age-dependent loss of expression of some cell markers. Conversely, cell markers not expressed in young animals may be detectable in their older counterparts. Histochemical age changes in carbohydrate profiles in the spinal cord have not been documented. In order to fill this information gap lectin histochemistry and image analysis were used to characterize the histochemical age changes occurring in the cervical segments of the rat spinal cord. From a battery of 11 lectins, the more important age changes were detected with Glicine maximus (SBA)-lectin. Thus, SBA-lectin neuronal staining which was moderately positive in the cervical segments of young animals was negative in old rats. In contrast the same lectin which did not react with the ependyma of young animals strongly bound to the ependyma of senescent rats. None of the tested lectins bound to glial cells, either in young or old animals. In no case the senile animals evidenced anatomopathological changes. We conclude that although in the aged spinal cord changes in lectin histochemical binding patterns occur, they do not reflect a pathologic situation. PMID:18992009

  7. Algebraic Proof Complexity: Progress, Frontiers and Challenges

    OpenAIRE

    Pitassi, Tonnian; Tzameret, Iddo

    2016-01-01

    We survey recent progress in the proof complexity of strong proof systems and its connection to algebraic circuit complexity, showing how the synergy between the two gives rise to new approaches to fundamental open questions, solutions to old problems, and new directions of research. In particular, we focus on tight connections between proof complexity lower bounds (namely, lower bounds on the size of proofs of certain tautologies), algebraic circuit lower bounds, and the Polynomial Identity ...

  8. Monotonicity of the quantum linear programming bound

    OpenAIRE

    Eric M. Rains

    1998-01-01

    The most powerful technique known at present for bounding the size of quantum codes of prescribed minimum distance is the quantum linear programming bound. Unlike the classical linear programming bound, it is not immediately obvious that if the quantum linear programming constraints are satisfiable for dimension K, that the constraints can be satisfied for all lower dimensions. We show that the quantum linear programming bound is indeed monotonic in this sense, and give an explicitly monotoni...

  9. Phase transformation of goethite into magnetite by reducing with carbohydrates

    Directory of Open Access Journals (Sweden)

    Dudchenko N.O.

    2015-09-01

    Full Text Available Phase transformations of synthetic goethite and goethite ore from Kryvyi Rih region by reducing with different carbohydrates (starch, glucose, fructose, sucrose and ascorbic acid were investigated by thermomagnetic analysis. Thermomagnetic analysis was carried-out using laboratory device that allows automatic registration of sample magnetization with the temperature (the rate of sample heating/cooling was 65-80°/min. The reduction reaction of synthetic goethite for all carbohydrates starts at the temperature of ~250°C while reduction of goethite ore for all carbohydrates starts at the temperature of ~450°C. We could relate this increasing of reduction start temperature with shielding effect of admixtures in the ore. Reduction of synthetic goethite at this temperature range leads to formation of magnetic phase with saturation magnetisation ~70 A*m2/kg. At the same time, reduction of goethite ore leads to formation of magnetic phase with saturation magnetisation ~25 A*m2/kg. One could attribute this decreased value of saturation magnetisation to the presence of other minerals (quartz, etc. in the ore. It was shown by X-Ray Diffraction method that goethite completely transforms into magnetite under heating with different carbohydrates up to 650°C. All carbohydrates reduce goethite to magnetite.

  10. Bound states in waveguides with complex Robin boundary conditions

    Czech Academy of Sciences Publication Activity Database

    Novák, Radek

    2016-01-01

    Roč. 96, 3-4 (2016), s. 251-281. ISSN 0921-7134 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : non-self-adjointness * waveguide * Robin boundary conditions * spectral analysis * essential spectrum * weak coupling * Birman-Schwinger principle * reality of the spectrum Subject RIV: BE - Theoretical Physics Impact factor: 0.528, year: 2014

  11. The Relationship Between Bound Water and Carbohydrate Reserves in Association with Cellular Integrity in Fragaria vesca Stored Under Different Conditions

    OpenAIRE

    Blanch, Maria; Sánchez-Ballesta, M. Teresa; Escribano, M. Isabel; Merodio, Carmen

    2015-01-01

    © 2014, The Author(s). It has been recognized that high CO2 concentrations maintain the freshness of strawberries, reducing weight loss and the incidence of decay. Since strawberries have high tolerance threshold to CO2, it is of interest to know what changes occur in cellular water distribution when the threshold is reached or exceeded. Moreover, as strawberries are prone to producing exudate during storage at low temperatures, application of technologies improving water retention is needed....

  12. Bound entangled states invariant under Ux

    Institute of Scientific and Technical Information of China (English)

    Wang Zhen; Wang Zhi-Xi

    2008-01-01

    This paper obtains an entangled condition for isotropic-like states by using an atomic map. It constructs a class of bound entangled states from the entangled condition and shows that the partial transposition of the state from the constructed bound entangled class is an edge bound entangled state by using range criterion.

  13. Bounded rationality and heterogeneous expectations in macroeconomics

    NARCIS (Netherlands)

    D. Massaro

    2012-01-01

    This thesis studies the effect of individual bounded rationality on aggregate macroeconomic dynamics. Boundedly rational agents are specified as using simple heuristics in their decision making. An important aspect of the type of bounded rationality described in this thesis is that the population of

  14. Upper Bounds on Numerical Approximation Errors

    DEFF Research Database (Denmark)

    Raahauge, Peter

    2004-01-01

    This paper suggests a method for determining rigorous upper bounds on approximationerrors of numerical solutions to infinite horizon dynamic programming models.Bounds are provided for approximations of the value function and the policyfunction as well as the derivatives of the value function. The...... approximations of a standard (strictly concave)growth model.KEYWORDS: Numerical approximation errors, Bellman contractions, Error bounds...

  15. Protein-carbohydrate interactions defining substrate specificity in Bacillus 1,3-1,4-beta-D-glucan 4-glucanohydrolases as dissected by mutational analysis.

    Science.gov (United States)

    Piotukh, K; Serra, V; Borriss, R; Planas, A

    1999-12-01

    The carbohydrate-binding site of Bacillus macerans 1,3-1, 4-beta-D-glucan 4-glucanohydrolase has been analyzed through a mutational analysis to probe the role of protein-carbohydrate interactions defining substrate specificity. Amino acid residues involved in substrate binding were proposed on the basis of a modeled enzyme-substrate complex [Hahn, M., Keitel, T., and Heinemann, U. (1995) Eur. J. Biochem. 232, 849-859]. The effects of the mutations at 15 selected residues on catalysis and binding were determined by steady-state kinetics using a series of chromogenic substrates of different degree of polymerization to assign the individual H-bond and hydrophobic contributions to individual subsites in the binding site cleft. The glucopyranose rings at subsites -III and -II are tightly bound by a number of H-bond interactions to Glu61, Asn24, Tyr92, and Asn180. From k(cat)/K(M) values, single H-bonds account for 1.8-2.2 kcal mol(-)(1) transition-state (TS) stabilization, and a charged H-bond contributes up to 3.5 kcal mol(-)(1). Glu61 forms a bidentated H-bond in subsites -III and -II, and provides up to 6.5 kcal mol(-)(1) TS stabilization. With a disaccharide substrate that fills subsites -I and -II, activation kinetics were observed for the wild-type and mutant enzymes except for mutations on Glu61, pointing to an important role of the bidentate interaction of Glu61 in two subsites. Whereas removal of the hydroxyl group of Tyr121, initially proposed to hydrogen-bond with the 2OH of Glcp-I, has essentially no effect (Y121F mutant), side-chain removal (Y121A mutant) gave a 100-fold reduction in k(cat)/K(M) and a 10-fold lower K(I) value with a competitive inhibitor. In subsite -IV, only a stacking interaction with Tyr22 (0.7 kcal mol(-)(1) TS stabilization) is observed. PMID:10587432

  16. Atoms as Qed bound atoms

    International Nuclear Information System (INIS)

    The relevance of Quantum Electrodynamics (Qed) in contemporary atomic structure theory is reviewed. Recent experimental advances allow both the production of heavy ions of high charge as well as the measurement of atomic properties with a precision never achieved before. The description of heavy atoms with few electrons via the successive incorporation of one, two, etcetera photons in a rigorous manner and within the bound state Furry representation of Qed is technically feasible. For many-electron atoms the many-body (correlation) effects are very important and it is practically impossible to evaluate all the relevant Feynman diagrams to the required accuracy. Thus, it is necessary to develop a theoretical scheme in which the radiative and nonradiative effects are taken into account in an effective way making emphasis in electronic correlation. Preserving gauge invariance, and avoiding both continuum dissolution and variational collapse are basic problems that must be solved when using effective potential methods and finite-basis representations of them. In this context, we shall discuss advances and problems in the description of atoms as Qed bound states. (Author)

  17. On Bounds for Spectra of Operator Pencils in a Hilbert Space

    Institute of Scientific and Technical Information of China (English)

    Michael Iosif GIL'

    2003-01-01

    A class of pencils (operator-valued functions of a complex argument) in a separable Hilbert space is considered. Bounds for the spectra are derived. Applications to differential operators, integral operators with delay and infinite matrix pencils are discussed.

  18. Carbohydrate mimetics and scaffolds: sweet spots in medicinal chemistry.

    Science.gov (United States)

    Cipolla, Laura; La Ferla, Barbara; Airoldi, Cristina; Zona, Cristiano; Orsato, Alexandre; Shaikh, Nasrin; Russo, Laura; Nicotra, Francesco

    2010-04-01

    Several glycoprocessing enzymes and glycoreceptors have been recognized as important targets for therapeutic intervention. This concept has inspired the development of important classes of therapeutics, such as anti-influenza drugs inhibiting influenza virus neuraminidase, anti-inflammatory drugs targeting lectin-sialyl-Lewis X interaction and glycosidase inhibitors against HIV, Gaucher's disease, hepatitis and cancer. These therapeutics are mainly carbohydrate mimics in which proper modifications permit stronger interactions with the target protein, higher stability, better pharmacokinetic properties and easier synthesis. Furthermore, the conformational rigidity and polyfunctionality of carbohydrates stimulate their use as scaffolds for the generation of libraries by combinatorial decoration with different pharmacophores. This mini-review will present examples of how to exploit carbohydrates mimics and scaffolds in drug research. PMID:21426009

  19. Microalgal carbohydrates. An overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Markou, Giorgos; Georgakakis, Dimitris [Agricultural Univ. of Athens (Greece). Dept. of Natural Resources Management and Agricultural Engineering; Angelidaki, Irini [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Environmental Engineering

    2012-11-15

    Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several cultivation techniques, such as nutrient starvation or other stressed environmental conditions, which cause the microalgae to accumulate carbohydrates. This paper attempts to give a general overview of techniques that can be used for increasing the microalgal biomass carbohydrate content. In addition, biomass conversion technologies, related to the conversion of carbohydrates into biofuels are discussed. (orig.)

  20. Characterization of carbohydrate-protein matrices for nutrient delivery.

    Science.gov (United States)

    Zhou, Yankun; Roos, Yrjö H

    2011-05-01

    Amorphous carbohydrates may show glass transition and crystallization as a result of thermal or water plasticization. Proteins often affect the state transitions of carbohydrates in carbohydrate-protein systems. Water sorption behavior and effects of water on glass transition and crystallization in freeze-dried lactose, trehalose, lactose-casein (3: 1), lactose-soy protein isolate (3:1), trehalose-casein (3:1), and trehalose-soy protein isolate (3:1) systems were studied. Water sorption was determined gravimetrically as a function of time, and Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were fitted to the experimental data. Glass transition temperature (T(g)) and instant crystallization temperature (T(ic)) in anhydrous and water plasticized systems were measured using differential scanning calorimetry (DSC). The Gordon-Taylor equation was used to model water content dependence of the T(g) values. The critical water content and water activity (a(w)) at 24 °C were calculated and crystallization of lactose and trehalose in the systems was followed at and above 0.54 a(w). Carbohydrate-protein systems showed higher amounts of sorbed water and less rapid sugar crystallization than pure sugars. A greater sugar crystallization delay was found in carbohydrate-casein systems than in carbohydrate-soy protein isolate systems. The T(g) and T(ic) values decreased with increasing water content and a(w). However, higher T(ic) values for lactose-protein systems were found than for lactose at the same a(w). Trehalose showed lower T(ic) value than lactose at 0.44 a(w) but no instant crystallization was measured below 0.44 a(w). State diagrams for each system are useful in selecting processing parameters and storage conditions in nutrient delivery applications. PMID:22417357