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Sample records for molecular recognition annual

  1. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali; Khashab, Niveen M.; Fahrenbach, Albert C.; Friedman, Douglas C.; Colvin, Michael T.; Coti, Karla K.; Bení tez, Diego S.; Tkatchouk, Ekaterina; Olsen, John Carl; Belowich, Matthew E.; Carmieli, Raanan; Khatib, Hussam A.; Goddard, William Andrew III; Wasielewski, Michael R.; Stoddart, Fraser Fraser Raser

    2009-01-01

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  2. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  3. Molecular Mechanisms of Odor Recognition

    National Research Council Canada - National Science Library

    Anholt, Robert

    2000-01-01

    .... We characterized the transduction pathway for the recognition of pheromones in the vomeronasal organ and also characterized subpopulations of olfactory neurons expressing different axonal G proteins...

  4. Pattern recognition in molecular dynamics. [FORTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, W H; Schieve, W C [Texas Univ., Austin (USA)

    1977-07-01

    An algorithm for the recognition of the formation of bound molecular states in the computer simulation of a dilute gas is presented. Applications to various related problems in physics and chemistry are pointed out. Data structure and decision processes are described. Performance of the FORTRAN program based on the algorithm in cooperation with the molecular dynamics program is described and the results are presented.

  5. Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

    Directory of Open Access Journals (Sweden)

    Rongning Liang

    2018-03-01

    Full Text Available Nowadays, it is still difficult for molecularly imprinted polymers (MIPs to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

  6. Soluble Molecularly Imprinted Nanorods for Homogeneous Molecular Recognition

    Science.gov (United States)

    Liang, Rongning; Wang, Tiantian; Zhang, Huan; Yao, Ruiqing; Qin, Wei

    2018-03-01

    Nowadays, it is still difficult for molecularly imprinted polymer (MIPs) to achieve homogeneous recognition since they cannot be easily dissolved in organic or aqueous phase. To address this issue, soluble molecularly imprinted nanorods have been synthesized by using soluble polyaniline doped with a functionalized organic protonic acid as the polymer matrix. By employing 1-naphthoic acid as a model, the proposed imprinted nanorods exhibit an excellent solubility and good homogeneous recognition ability. The imprinting factor for the soluble imprinted nanoroads is 6.8. The equilibrium dissociation constant and the apparent maximum number of the proposed imprinted nanorods are 248.5 μM and 22.1 μmol/g, respectively. We believe that such imprinted nanorods may provide an appealing substitute for natural receptors in homogeneous recognition related fields.

  7. Molecular Recognition in the Colloidal World.

    Science.gov (United States)

    Elacqua, Elizabeth; Zheng, Xiaolong; Shillingford, Cicely; Liu, Mingzhu; Weck, Marcus

    2017-11-21

    Colloidal self-assembly is a bottom-up technique to fabricate functional nanomaterials, with paramount interest stemming from programmable assembly of smaller building blocks into dynamic crystalline domains and photonic materials. Multiple established colloidal platforms feature diverse shapes and bonding interactions, while achieving specific orientations along with short- and long-range order. A major impediment to their universal use as building blocks for predesigned architectures is the inability to precisely dictate and control particle functionalization and concomitant reversible self-assembly. Progress in colloidal self-assembly necessitates the development of strategies that endow bonding specificity and directionality within assemblies. Methodologies that emulate molecular and polymeric three-dimensional (3D) architectures feature elements of covalent bonding, while high-fidelity molecular recognition events have been installed to realize responsive reconfigurable assemblies. The emergence of anisotropic 'colloidal molecules', coupled with the ability to site-specifically decorate particle surfaces with supramolecular recognition motifs, has facilitated the formation of superstructures via directional interactions and shape recognition. In this Account, we describe supramolecular assembly routes to drive colloidal particles into precisely assembled architectures or crystalline lattices via directional noncovalent molecular interactions. The design principles are based upon the fabrication of colloidal particles bearing surface-exposed functional groups that can undergo programmable conjugation to install recognition motifs with high fidelity. Modular and versatile by design, our strategy allows for the introduction and integration of molecular recognition principles into the colloidal world. We define noncovalent molecular interactions as site-specific forces that are predictable (i.e., feature selective and controllable complementary bonding partners

  8. Entropy in molecular recognition by proteins.

    Science.gov (United States)

    Caro, José A; Harpole, Kyle W; Kasinath, Vignesh; Lim, Jackwee; Granja, Jeffrey; Valentine, Kathleen G; Sharp, Kim A; Wand, A Joshua

    2017-06-20

    Molecular recognition by proteins is fundamental to molecular biology. Dissection of the thermodynamic energy terms governing protein-ligand interactions has proven difficult, with determination of entropic contributions being particularly elusive. NMR relaxation measurements have suggested that changes in protein conformational entropy can be quantitatively obtained through a dynamical proxy, but the generality of this relationship has not been shown. Twenty-eight protein-ligand complexes are used to show a quantitative relationship between measures of fast side-chain motion and the underlying conformational entropy. We find that the contribution of conformational entropy can range from favorable to unfavorable, which demonstrates the potential of this thermodynamic variable to modulate protein-ligand interactions. For about one-quarter of these complexes, the absence of conformational entropy would render the resulting affinity biologically meaningless. The dynamical proxy for conformational entropy or "entropy meter" also allows for refinement of the contributions of solvent entropy and the loss in rotational-translational entropy accompanying formation of high-affinity complexes. Furthermore, structure-based application of the approach can also provide insight into long-lived specific water-protein interactions that escape the generic treatments of solvent entropy based simply on changes in accessible surface area. These results provide a comprehensive and unified view of the general role of entropy in high-affinity molecular recognition by proteins.

  9. Molecular Recognition Units: Design and diagnostic applications

    International Nuclear Information System (INIS)

    Alvarez, V.L.; Radcliffe, R.D.; Coughlin, D.J.; Lopes, A.D.; Rodwell, J.D.

    1992-01-01

    Molecular Recognition Units (MRUs), small peptides derived from complementarity-determining region (CDR) of IgM antibodies, can mimic the recognition site found in the antibody. One example of an MRU fusion peptide designed to image thrombi was derived from PAC 1.1, an IgM monoclonal antibody specific for the GPIIb/IIa receptor on platelets. The peptide sequence from the third CDR of the heavy chain was engineered for optimal binding activity and synthesized with a metal-binding peptide sequence. After labeling with 99m-Tc, the peptides were injected into either animal models of experimentally induced thrombi in order to determine their effectiveness in imaging model thrombi. Data are presented which demonstrate enhanced binding with open-quotes tandem repeatsclose quotes of the MRU domain and no loss of activity after incorporation of the metal-binding domain. These studies have led to a clinical candidate consisting of 17 amino acids. Extension of this concept to other MRUs and fusion peptides is also discussed

  10. Molecular Recognition: Detection of Colorless Compounds Based on Color Change

    Science.gov (United States)

    Khalafi, Lida; Kashani, Samira; Karimi, Javad

    2016-01-01

    A laboratory experiment is described in which students measure the amount of cetirizine in allergy-treatment tablets based on molecular recognition. The basis of recognition is competition of cetirizine with phenolphthalein to form an inclusion complex with ß-cyclodextrin. Phenolphthalein is pinkish under basic condition, whereas it's complex form…

  11. Signatures of molecular recognition from the topography of ...

    Indian Academy of Sciences (India)

    Administrator

    cules through non-covalent bonding such as hydro- gen bonding ... tion exhibit complementarity of certain properties ... of molecular recognition has been given in terms of .... VA and VB correspond to the monomer MESP in the composite.

  12. Environmental Molecular Sciences Laboratory 2004 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    White, Julia C.

    2005-04-17

    This 2004 Annual Report describes the research and accomplishments of staff and users of the W.R. Wiley Environmental Molecular Sciences Laboratory (EMSL), located in Richland, Washington. EMSL is a multidisciplinary, national scientific user facility and research organization, operated by Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy's Office of Biological and Environmental Research. The resources and opportunities within the facility are an outgrowth of the U.S. Department of Energy's (DOE) commitment to fundamental research for understanding and resolving environmental and other critical scientific issues.

  13. Molecular Recognition Involving Anthraquinone Derivatives and Molecular Clips

    Science.gov (United States)

    Alaparthi, Madhubabu

    In the past, we have demonstrated that 1,8-anthraquinone-18-crown-5 (1) and its heterocyclic derivatives act as luminescent hosts for a variety of cations of environmental and clinical concern. We report here a series of heteroatom-substituted macrocycles containing an anthraquinone moiety as a fluorescent signaling unit and a cyclic polyheteroether chain as the receptor. Sulfur, selenium, and tellurium derivatives of 1,8-anthraquinone-18-crown-5 (1) were synthesized by reacting sodium sulfide (Na2S), sodium selenide (Na2Se) and sodium telluride (Na2Te) with 1,8-bis(2-bromoethylethyleneoxy)anthracene - 9,10-dione in a 1:1 ratio (2,3, and 6). These sensors bind metal ions in a 1:1 ratio (7 and 8), and the optical properties of the new complexes were examined and the sulfur and selenium analogues show that selectivity for Pb(II) is markedly improved as compared to the oxygen analogue 1 which was competitive for Ca(II) ion. Selective reduction of 1 yields secondary alcohols where either one or both of the anthraquinone carbonyl groups has been reduced ( 15 and 9). A new mechanism for the fluorescence detection of metal cations in solution is introduced involving a unique keto-enol tautomerization. Reduction of 1 yields the doubly reduced secondary alcohol, 9. 9 acts as a chemodosimeter for Al(III) ion producing a strong blue emission due to the formation of the anthracene fluorophore, 10, via dehydration of the internal secondary alcohol in DMSO/aqueous solution. The enol form is not the most thermodynamically stable form under these conditions however, and slowly converts to the keto form 11.. Currently we are focusing on cucurbituril derivatives, also described as molecular clips due to their folded geometry used as molecular recognition hosts. We first investigated the synthesis and characterization of aromatic methoxy/catechol terminated cucurbituril units that act as hosts for small solvent molecules, such as CH2Cl2, CH3CN, DMF, and MeOH, through dual pi...H-C T

  14. Molecular recognition by gold, silver and copper nanoparticles

    Science.gov (United States)

    Tauran, Yannick; Brioude, Arnaud; Coleman, Anthony W; Rhimi, Moez; Kim, Beonjoom

    2013-01-01

    The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common methods of functionalization: Electrostatic adsorption; Chemisorption; Affinity-based coordination is given. In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition. In the main section the various types of capping agents for molecular recognition; nucleic acid coatings, protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications. Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition. For the proteins the recognition properties of antibodies form the core of the section. With respect to the supramolecular systems the cyclodextrins, calix[n]arenes, dendrimers, crown ethers and the cucurbitales are treated in depth. Finally a short section deals with the possible toxicity of the nanoparticles, a concern in public health. PMID:23977421

  15. Creating molecular macrocycles for anion recognition

    Directory of Open Access Journals (Sweden)

    Amar H. Flood

    2016-03-01

    Full Text Available The creation and functionality of new classes of macrocycles that are shape persistent and can bind anions is described. The genesis of triazolophane macrocycles emerges out of activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted upon in the creation of two new macrocycles. First, cyanostars are larger and like to capture large anions. Second is tricarb, which also favors large anions but shows a propensity to self-assemble in an orderly and stable manner, laying a foundation for future designs of hierarchical nanostructures.

  16. Specific Electrostatic Molecular Recognition in Water

    DEFF Research Database (Denmark)

    Li, Ming; Hoeck, Casper; Schoffelen, Sanne

    2016-01-01

    The identification of pairs of small peptides that recognize each other in water exclusively through electrostatic interactions is reported. The target peptide and a structure-biased combinatorial ligand library consisting of ≈78 125 compounds were synthesized on different sized beads. Peptide......-bead binding assay and by 2D NMR spectroscopy. Molecular dynamics (MD) studies revealed a putative mode of interaction for this unusual electrostatic binding event. High binding specificity occurred through a combination of topological matching and electrostatic and hydrogen-bond complementarities. From MD...

  17. Molecular recognition in protein modification with rhodium metallopeptides

    Science.gov (United States)

    Ball, Zachary T.

    2015-01-01

    Chemical manipulation of natural, unengineered proteins is a daunting challenge which tests the limits of reaction design. By combining transition-metal or other catalysts with molecular recognition ideas, it is possible to achieve site-selective protein reactivity without the need for engineered recognition sequences or reactive sites. Some recent examples in this area have used ruthenium photocatalysis, pyridine organocatalysis, and rhodium(II) metallocarbene catalysis, indicating that the fundamental ideas provide opportunities for using diverse reactivity on complex protein substrates and in complex cell-like environments. PMID:25588960

  18. Control of Target Molecular Recognition in a Small Pore Space with Biomolecule-Recognition Gating Membrane.

    Science.gov (United States)

    Okuyama, Hiroto; Oshiba, Yuhei; Ohashi, Hidenori; Yamaguchi, Takeo

    2018-05-01

    A biomolecule-recognition gating membrane, which introduces thermosensitive graft polymer including molecular recognition receptor into porous membrane substrate, can close its pores by recognizing target biomolecule. The present study reports strategies for improving both versatility and sensitivity of the gating membrane. First, the membrane is fabricated by introducing the receptor via a selectively reactive click reaction improving the versatility. Second, the sensitivity of the membrane is enhanced via an active delivering method of the target molecules into the pores. In the method, the tiny signal of the target biomolecule is amplified as obvious pressure change. Furthermore, this offers 15 times higher sensitivity compared to the previously reported passive delivering method (membrane immersion to sample solution) with significantly shorter recognition time. The improvement will aid in applying the gating membrane to membrane sensors in medical fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Programmable molecular recognition based on the geometry of DNA nanostructures.

    Science.gov (United States)

    Woo, Sungwook; Rothemund, Paul W K

    2011-07-10

    From ligand-receptor binding to DNA hybridization, molecular recognition plays a central role in biology. Over the past several decades, chemists have successfully reproduced the exquisite specificity of biomolecular interactions. However, engineering multiple specific interactions in synthetic systems remains difficult. DNA retains its position as the best medium with which to create orthogonal, isoenergetic interactions, based on the complementarity of Watson-Crick binding. Here we show that DNA can be used to create diverse bonds using an entirely different principle: the geometric arrangement of blunt-end stacking interactions. We show that both binary codes and shape complementarity can serve as a basis for such stacking bonds, and explore their specificity, thermodynamics and binding rules. Orthogonal stacking bonds were used to connect five distinct DNA origami. This work, which demonstrates how a single attractive interaction can be developed to create diverse bonds, may guide strategies for molecular recognition in systems beyond DNA nanostructures.

  20. Fluorescent and Colorimetric Molecular Recognition Probe for Hydrogen Bond Acceptors

    OpenAIRE

    Pike, Sarah Jane; Hunter, Christopher Alexander

    2018-01-01

    The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish sel...

  1. Preparation and Property Recognition of Nimodipine Molecularly Imprinted Polymer

    Directory of Open Access Journals (Sweden)

    Fei-fei CHEN

    2015-09-01

    Full Text Available Objective: To explore the application of molecular imprinting technique in the separation and detection of nimodipine. Methods: Methacrylic acid as functional monomer, pentaerythritol triacrylate as cross-linking agent were used to prepare molecularly imprinted polymer (MIP with the feature of specific recognition performance on imprinting molecule nimodipine under condition of template molecule nimodipine. The preparation conditions, recognition performance of MIP on nimodipine, different proportions of template molecule and functional monomer, the selectivity to other substrate, and the relationship between adsorption quantity (Q and time were observed. Results: MIP was prepared successfully bynimodipine as template and pentaerythritol triacrylate as cross-linking agent, with the feature of specific recognition performance on nimodipine. The static adsorption distribution coefficient (KD was 0.2264. The equation of Q and the concentration of substrate of template MIP was y = -0.21x+0.2204. Combining capacity of template molecule at the same concentration enhanced with the increasing proportion of functional monomer.Conclusion: Nimodipine MIP based on molecular imprinting technique may become a new approach to chiral separation for nimodipine.

  2. Molecular imprinting at walls of silica nanotubes for TNT recognition.

    Science.gov (United States)

    Xie, Chenggen; Liu, Bianhua; Wang, Zhenyang; Gao, Daming; Guan, Guijian; Zhang, Zhongping

    2008-01-15

    This paper reports the molecular imprinting at the walls of highly uniform silica nanotubes for the recognition of 2,4,6-trinitrotoluene (TNT). It has been demonstrated that TNT templates were efficiently imprinted into the matrix of silica through the strong acid-base pairing interaction between TNT and 3-aminopropyltriethoxysilane (APTS). TNT-imprinted silica nanotubes were synthesized by the gelation reaction between APTS and tetraethylorthosilicate (TEOS), selectively occurring at the porous walls of APTS-modified alumina membranes. The removal of the original TNT templates leaves the imprinted cavities with covalently anchored amine groups at the cavity walls. A high density of recognition sites with molecular selectivity to the TNT analyte was created at the wall of silica nanotubes. Furthermore, most of these recognition sites are situated at the inside and outside surfaces of tubular walls and in the proximity of the two surfaces due to the ultrathin wall thickness of only 15 nm, providing a better site accessibility and lower mass-transfer resistance. Therefore, greater capacity and faster kinetics of uptaking target species were achieved. The silica nanotube reported herein is an ideal form of material for imprinting various organic or biological molecules toward applications in chemical/biological sensors and bioassay.

  3. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

    Energy Technology Data Exchange (ETDEWEB)

    Kan Xianwen; Geng Zhirong; Zhao Yao; Wang Zhilin; Zhu Junjie [State Key Laboratory of Coordination Chemistry, MOE Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)], E-mail: wangzl@nju.edu.cn, E-mail: jjzhu@nju.edu.cn

    2009-04-22

    Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe{sub 3}O{sub 4} nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

  4. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

    International Nuclear Information System (INIS)

    Kan Xianwen; Geng Zhirong; Zhao Yao; Wang Zhilin; Zhu Junjie

    2009-01-01

    Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe 3 O 4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

  5. Molecular recognition on a cavitand-functionalized silicon surface.

    Science.gov (United States)

    Biavardi, Elisa; Favazza, Maria; Motta, Alessandro; Fragalà, Ignazio L; Massera, Chiara; Prodi, Luca; Montalti, Marco; Melegari, Monica; Condorelli, Guglielmo G; Dalcanale, Enrico

    2009-06-03

    A Si(100) surface featuring molecular recognition properties was obtained by covalent functionalization with a tetraphosphonate cavitand (Tiiii), able to complex positively charged species. Tiiii cavitand was grafted onto the Si by photochemical hydrosilylation together with 1-octene as a spatial spectator. The recognition properties of the Si-Tiiii surface were demonstrated through two independent analytical techniques, namely XPS and fluorescence spectroscopy, during the course of reversible complexation-guest exchange-decomplexation cycles with specifically designed ammonium and pyridinium salts. Control experiments employing a Si(100) surface functionalized with a structurally similar, but complexation inactive, tetrathiophosphonate cavitand (TSiiii) demonstrated no recognition events. This provides evidence for the complexation properties of the Si-Tiiii surface, ruling out the possibility of nonspecific interactions between the substrate and the guests. The residual Si-O(-) terminations on the surface replace the guests' original counterions, thus stabilizing the complex ion pairs. These results represent a further step toward the control of self-assembly of complex supramolecular architectures on surfaces.

  6. Molecular Science Research Center, 1991 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Knotek, M.L.

    1992-03-01

    During 1991, the Molecular Science Research Center (MSRC) experienced solid growth and accomplishment and the Environmental, and Molecular Sciences Laboratory (EMSL) construction project moved forward. We began with strong programs in chemical structure and dynamics and theory, modeling, and simulation, and both these programs continued to thrive. We also made significant advances in the development of programs in materials and interfaces and macromolecular structure and dynamics, largely as a result of the key staff recruited to lead these efforts. If there was one pervasive activity for the past year, however, it was to strengthen the role of the EMSL in the overall environmental restoration and waste management (ER/WM) mission at Hanford. These extended activities involved not only MSRC and EMSL staff but all PNL scientific and technical staff engaged in ER/WM programs.

  7. Molecular Science Research Center 1992 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Knotek, M.L.

    1994-01-01

    The Molecular Science Research Center is a designated national user facility, available to scientists from universities, industry, and other national laboratories. After an opening section, which includes conferences hosted, appointments, and projects, this document presents progress in the following fields: chemical structure and dynamics; environmental dynamics and simulation; macromolecular structure and dynamics; materials and interfaces; theory, modeling, and simulation; and computing and information sciences. Appendices are included: MSRC staff and associates, 1992 publications and presentations, activities, and acronyms and abbreviations.

  8. DNAzyme Feedback Amplification: Relaying Molecular Recognition to Exponential DNA Amplification.

    Science.gov (United States)

    Liu, Meng; Yin, Qingxin; McConnell, Erin M; Chang, Yangyang; Brennan, John D; Li, Yingfu

    2018-03-26

    Technologies capable of linking DNA amplification to molecular recognition are very desirable for ultrasensitive biosensing applications. We have developed a simple but powerful isothermal DNA amplification method, termed DNAzyme feedback amplification (DFA), that is capable of relaying molecular recognition to exponential DNA amplification. The method incorporates both an RNA-cleaving DNAzyme (RCD) and rolling circle amplification (RCA) carried out by a special DNA polymerase using a circular DNA template. DFA begins with a stimulus-dependent RCA reaction, producing tandemly linked RCDs in long-chain DNA products. These RCDs cleave an RNA-containing DNA sequence to form additional primers that hybridize to the circular DNA molecule, giving rise to DNA assemblies that act as the new inputs for RCA. The RCA reaction and the cleavage event keep on feeding each other autonomously, resulting in exponential growth of repetitive DNA sequences that can be easily detected. This method can be used for the detection of both nucleic acid based targets and non-nucleic acid analytes. In this article, we discuss the conceptual framework of the feedback amplification approach, the essential features of this method as well as remaining challenges and possible solutions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Fluorescent and colorimetric molecular recognition probe for hydrogen bond acceptors.

    Science.gov (United States)

    Pike, Sarah J; Hunter, Christopher A

    2017-11-22

    The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish self-consistent H-bond acceptor parameters (β) for benzoate, azide, chloride, thiocyanate anions, a series of phosphine oxides, phosphate ester, sulfoxide and a tertiary amide. The results demonstrate both the transferability of H-bond parameters between different solvents and the utility of the naphthol-based dual molecular recognition probe to exploit orthogonal spectroscopic techniques to determine the HBA properties of neutral and charged solutes. The benzoate anion is the strongest HBA studied with a β parameter of 15.4, and the neutral tertiary amide is the weakest H-bond acceptor investigated with a β parameter of 8.5. The H-bond acceptor strength of the azide anion is higher than that of chloride (12.8 and 12.2 respectively), and the thiocyanate anion has a β value of 10.8 and thus is a significantly weaker H-bond acceptor than both the azide and chloride anions.

  10. Molecular Science Research Center annual report

    Energy Technology Data Exchange (ETDEWEB)

    Knotek, M.L.

    1991-01-01

    The Chemical Structure and Dynamics group is studying chemical kinetics and reactions dynamics of terrestrial and atmospheric processes as well as the chemistry of complex waste forms and waste storage media. Staff are using new laser systems and surface-mapping techniques in combination with molecular clusters that mimic adsorbate/surface interactions. The Macromolecular Structure and Dynamics group is determining biomolecular structure/function relationships for processes the control the biological transformation of contaminants and the health effects of toxic substances. The Materials and Interfaces program is generating information needed to design and synthesize advanced materials for the analysis and separation of mixed chemical waste, the long-term storage of concentrated hazardous materials, and the development of chemical sensors for environmental monitoring of various organic and inorganic species. The Theory, Modeling, and Simulation group is developing detailed molecular-level descriptions of the chemical, physical, and biological processes in natural and contaminated systems. Researchers are using the full spectrum of computational techniques. The Computer and Information Sciences group is developing new approaches to handle vast amounts of data and to perform calculations for complex natural systems. The EMSL will contain a high-performance computing facility, ancillary computing laboratories, and high-speed data acquisition systems for all major research instruments.

  11. Molecular recognition in complexes of TRF proteins with telomeric DNA.

    Directory of Open Access Journals (Sweden)

    Miłosz Wieczór

    Full Text Available Telomeres are specialized nucleoprotein assemblies that protect the ends of linear chromosomes. In humans and many other species, telomeres consist of tandem TTAGGG repeats bound by a protein complex known as shelterin that remodels telomeric DNA into a protective loop structure and regulates telomere homeostasis. Shelterin recognizes telomeric repeats through its two major components known as Telomere Repeat-Binding Factors, TRF1 and TRF2. These two homologous proteins are therefore essential for the formation and normal function of telomeres. Indeed, TRF1 and TRF2 are implicated in a plethora of different cellular functions and their depletion leads to telomere dysfunction with chromosomal fusions, followed by apoptotic cell death. More specifically, it was found that TRF1 acts as a negative regulator of telomere length, and TRF2 is involved in stabilizing the loop structure. Consequently, these proteins are of great interest, not only because of their key role in telomere maintenance and stability, but also as potential drug targets. In the current study, we investigated the molecular basis of telomeric sequence recognition by TRF1 and TRF2 and their DNA binding mechanism. We used molecular dynamics (MD to calculate the free energy profiles for binding of TRFs to telomeric DNA. We found that the predicted binding free energies were in good agreement with experimental data. Further, different molecular determinants of binding, such as binding enthalpies and entropies, the hydrogen bonding pattern and changes in surface area, were analyzed to decompose and examine the overall binding free energies at the structural level. With this approach, we were able to draw conclusions regarding the consecutive stages of sequence-specific association, and propose a novel aspartate-dependent mechanism of sequence recognition. Finally, our work demonstrates the applicability of computational MD-based methods to studying protein-DNA interactions.

  12. Quantum origins of molecular recognition and olfaction in Drosophila.

    Science.gov (United States)

    Bittner, Eric R; Madalan, Adrian; Czader, Arkadiusz; Roman, Gregg

    2012-12-14

    The standard model for molecular recognition of an odorant is that receptor sites discriminate by molecular geometry as evidenced that two chiral molecules may smell very differently. However, recent studies of isotopically labeled olfactants indicate that there may be a molecular vibration-sensing component to olfactory reception, specifically in the spectral region around 2300 cm(-1). Here, we present a donor-bridge-acceptor model for olfaction which attempts to explain this effect. Our model, based upon accurate quantum chemical calculations of the olfactant (bridge) in its neutral and ionized states, posits that internal modes of the olfactant are excited impulsively during hole transfer from a donor to acceptor site on the receptor, specifically those modes that are resonant with the tunneling gap. By projecting the impulsive force onto the internal modes, we can determine which modes are excited at a given value of the donor-acceptor tunneling gap. Only those modes resonant with the tunneling gap and are impulsively excited will give a significant contribution to the inelastic transfer rate. Using acetophenone as a test case, our model and experiments on D. melanogaster suggest that isotopomers of a given olfactant give rise to different odorant qualities. These results support the notion that inelastic scattering effects may play a role in discriminating between isotopomers but that this is not a general spectroscopic effect.

  13. Consequences of Morphology on Molecularly Imprinted Polymer-Ligand Recognition

    Directory of Open Access Journals (Sweden)

    Annika M. Rosengren

    2013-01-01

    Full Text Available The relationship between molecularly imprinted polymer (MIP morphology and template-rebinding over a series of warfarin-imprinted methacrylic acid co(ethylene dimethacrylate polymers has been explored. Detailed investigations of the nature of template recognition revealed that an optimal template binding was obtained with polymers possessing a narrow population of pores (~3–4 nm in the mesopore size range. Importantly, the warfarin-polymer rebinding analyses suggest strategies for regulating ligand binding capacity and specificity through variation of the degree of cross-linking, where polymers prepared with a lower degree of cross-linking afford higher capacity though non-specific in character. In contrast, the co-existence of specific and non-specific binding was found in conjunction with higher degrees of cross-linking and resultant meso- and macropore size distributions.

  14. Structural insight into RNA recognition motifs: versatile molecular Lego building blocks for biological systems.

    Science.gov (United States)

    Muto, Yutaka; Yokoyama, Shigeyuki

    2012-01-01

    'RNA recognition motifs (RRMs)' are common domain-folds composed of 80-90 amino-acid residues in eukaryotes, and have been identified in many cellular proteins. At first they were known as RNA binding domains. Through discoveries over the past 20 years, however, the RRMs have been shown to exhibit versatile molecular recognition activities and to behave as molecular Lego building blocks to construct biological systems. Novel RNA/protein recognition modes by RRMs are being identified, and more information about the molecular recognition by RRMs is becoming available. These RNA/protein recognition modes are strongly correlated with their biological significance. In this review, we would like to survey the recent progress on these versatile molecular recognition modules. Copyright © 2012 John Wiley & Sons, Ltd.

  15. Molecular tips for scanning tunneling microscopy: intermolecular electron tunneling for single-molecule recognition and electronics.

    Science.gov (United States)

    Nishino, Tomoaki

    2014-01-01

    This paper reviews the development of molecular tips for scanning tunneling microscopy (STM). Molecular tips offer many advantages: first is their ability to perform chemically selective imaging because of chemical interactions between the sample and the molecular tip, thus improving a major drawback of conventional STM. Rational design of the molecular tip allows sophisticated chemical recognition; e.g., chiral recognition and selective visualization of atomic defects in carbon nanotubes. Another advantage is that they provide a unique method to quantify electron transfer between single molecules. Understanding such electron transfer is mandatory for the realization of molecular electronics.

  16. Molecularly Imprinted Polymers: Thermodynamic and Kinetic Considerations on the Specific Sorption and Molecular Recognition

    Directory of Open Access Journals (Sweden)

    Kejun Tong

    2008-04-01

    Full Text Available This article presents a work aiming at thermodynamically and kinetically interpreting the specific sorption and recognition by a molecularly imprinted polymer. Using Boc-L-Phe-OH as a template, the imprinted material was prepared. The result indicates that the prepared polymer can well discriminate the imprint species from its analogue (Boc-D-Phe-OH, so as to adsorb more for the former but less for the latter. Kinetic analysis indicates that this specific sorption, in nature, can be a result of a preferential promotion. The imprint within the polymer causes a larger adsorption rate for the template than for the analogue. Thermodynamic study also implies that the molecular induction from the specific imprint to the template is larger than to the analogue, which thus makes the polymer capable of preferentially alluring the template to bind.

  17. Effect of buffer at nanoscale molecular recognition interfaces - electrostatic binding of biological polyanions.

    Science.gov (United States)

    Rodrigo, Ana C; Laurini, Erik; Vieira, Vânia M P; Pricl, Sabrina; Smith, David K

    2017-10-19

    We investigate the impact of an over-looked component on molecular recognition in water-buffer. The binding of a cationic dye to biological polyanion heparin is shown by isothermal calorimetry to depend on buffer (Tris-HCl > HEPES > PBS). The heparin binding of self-assembled multivalent (SAMul) cationic micelles is even more buffer dependent. Multivalent electrostatic molecular recognition is buffer dependent as a result of competitive interactions between the cationic binding interface and anions present in the buffer.

  18. Molecular basis for convergent evolution of glutamate recognition by pentameric ligand-gated ion channels

    DEFF Research Database (Denmark)

    Lynagh, Timothy; Beech, Robin N.; Lalande, Maryline J.

    2015-01-01

    that glutamate recognition requires an arginine residue in the base of the binding site, which originated at least three distinct times according to phylogenetic analysis. Most remarkably, the arginine emerged on the principal face of the binding site in the Lophotrochozoan lineage, but 65 amino acids upstream......Glutamate is an indispensable neurotransmitter, triggering postsynaptic signals upon recognition by postsynaptic receptors. We questioned the phylogenetic position and the molecular details of when and where glutamate recognition arose in the glutamate-gated chloride channels. Experiments revealed......, on the complementary face, in the Ecdysozoan lineage. This combined experimental and computational approach throws new light on the evolution of synaptic signalling....

  19. Confinement of Aggregation-Induced Emission Molecular Rotors in Ultrathin Two-Dimensional Porous Organic Nanosheets for Enhanced Molecular Recognition.

    Science.gov (United States)

    Dong, Jinqiao; Li, Xu; Zhang, Kang; Di Yuan, Yi; Wang, Yuxiang; Zhai, Linzhi; Liu, Guoliang; Yuan, Daqiang; Jiang, Jianwen; Zhao, Dan

    2018-03-21

    Despite the rapid development of molecular rotors over the past decade, it still remains a huge challenge to understand their confined behavior in ultrathin two-dimensional (2D) nanomaterials for molecular recognition. Here, we report an all-carbon, 2D π-conjugated aromatic polymer, named NUS-25, containing flexible tetraphenylethylene (TPE) units as aggregation-induced emission (AIE) molecular rotors. NUS-25 bulk powder can be easily exfoliated into micrometer-sized lamellar freestanding nanosheets with a thickness of 2-5 nm. The dynamic behavior of the TPE rotors is partially restricted through noncovalent interactions in the ultrathin 2D nanosheets, which is proved by comparative experimental studies including AIE characteristics, size-selective molecular recognition, and theoretical calculations of rotary energy barrier. Because of the partially restricted TPE rotors, NUS-25 nanosheets are highly fluorescent. This property allows NUS-25 nanosheets to be used as a chemical sensor for the specific detection of acenaphthylene among a series of polycyclic aromatic hydrocarbons (PAHs) via fluorescent quenching mechanism. Further investigations show that NUS-25 nanosheets have much higher sensitivity and selectivity than their stacked bulk powder and other similar polymers containing dynamic TPE rotors. The highly efficient molecular recognition can be attributed to the photoinduced electron transfer (PET) from NUS-25 nanosheets to acenaphthylene, which is investigated by time-resolved photoluminescence measurements (TRPL), excitation and emission spectra, and density functional theory (DFT) calculations. Our findings demonstrate that confinement of AIE molecular rotors in 2D nanomaterials can enhance the molecular recognition. We anticipate that the material design strategy demonstrated in this study will inspire the development of other ultrathin 2D nanomaterials equipped with smart molecular machines for various applications.

  20. Molecularly imprinted polymers for the recognition of proteins: the state of the art.

    Science.gov (United States)

    Bossi, A; Bonini, F; Turner, A P F; Piletsky, S A

    2007-01-15

    Molecular imprinting has proved to be an effective technique for the creation of recognition sites on a polymer scaffold. Protein imprinting has been a focus for many chemists working in the area of molecular recognition, since the creation of synthetic polymers that can specifically recognise proteins is a very challenging but potentially extremely rewarding objective. It is expected that molecularly imprinted polymers (MIPs) with specificity for proteins will find application in medicine, diagnostics, proteomics, environmental analysis, sensors and drug delivery. In this review, the authors provide an overview of the progress achieved in the decade between 1994 and 2005, with respect to the challenging area of MIPs for protein recognition. The discussion furnishes a comparative analysis of different approaches developed, underlining their relative advantages and disadvantages and highlighting trends and possible future directions.

  1. Recognition of conformational changes in beta-lactoglobulin by molecularly imprinted thin films.

    Science.gov (United States)

    Turner, Nicholas W; Liu, Xiao; Piletsky, Sergey A; Hlady, Vladimir; Britt, David W

    2007-09-01

    Pathogenesis in protein conformational diseases is initiated by changes in protein secondary structure. This molecular restructuring presents an opportunity for novel shape-based detection approaches, as protein molecular weight and chemistry are otherwise unaltered. Here we apply molecular imprinting to discriminate between distinct conformations of the model protein beta-lactoglobulin (BLG). Thermal- and fluoro-alcohol-induced BLG isoforms were imprinted in thin films of 3-aminophenylboronic acid on quartz crystal microbalance chips. Enhanced rebinding of the template isoform was observed in all cases when compared to the binding of nontemplate isoforms over the concentration range of 1-100 microg mL(-1). Furthermore, it was observed that the greater the changes in the secondary structure of the template protein the lower the binding of native BLG challenges to the imprint, suggesting a strong steric influence in the recognition system. This feasibility study is a first demonstration of molecular imprints for recognition of distinct conformations of the same protein.

  2. Protein recognition by a pattern-generating fluorescent molecular probe

    Science.gov (United States)

    Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M.; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M.; Motiei, Leila; Margulies, David

    2017-12-01

    Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

  3. Dynamic combinatorial libraries: from exploring molecular recognition to systems chemistry.

    Science.gov (United States)

    Li, Jianwei; Nowak, Piotr; Otto, Sijbren

    2013-06-26

    Dynamic combinatorial chemistry (DCC) is a subset of combinatorial chemistry where the library members interconvert continuously by exchanging building blocks with each other. Dynamic combinatorial libraries (DCLs) are powerful tools for discovering the unexpected and have given rise to many fascinating molecules, ranging from interlocked structures to self-replicators. Furthermore, dynamic combinatorial molecular networks can produce emergent properties at systems level, which provide exciting new opportunities in systems chemistry. In this perspective we will highlight some new methodologies in this field and analyze selected examples of DCLs that are under thermodynamic control, leading to synthetic receptors, catalytic systems, and complex self-assembled supramolecular architectures. Also reviewed are extensions of the principles of DCC to systems that are not at equilibrium and may therefore harbor richer functional behavior. Examples include self-replication and molecular machines.

  4. All-organic microelectromechanical systems integrating specific molecular recognition--a new generation of chemical sensors.

    Science.gov (United States)

    Ayela, Cédric; Dubourg, Georges; Pellet, Claude; Haupt, Karsten

    2014-09-03

    Cantilever-type all-organic microelectromechanical systems based on molecularly imprinted polymers for specific analyte recognition are used as chemical sensors. They are produced by a simple spray-coating-shadow-masking process. Analyte binding to the cantilever generates a measurable change in its resonance frequency. This allows label-free detection by direct mass sensing of low-molecular-weight analytes at nanomolar concentrations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Design of supramolecular nanomaterials : from molecular recognition to hierarchical self-assembly

    OpenAIRE

    El Idrissi, Mohamed

    2017-01-01

    In the present thesis, are reported new strategies for the design of nanostructures to partly address environmental issues. The work carried out has been divided into three parts: the design of cyclodextrin (CD)-based polymeric materials, the molecular engineering of a pyrene derivative for the formation of self-assembled nanostructures and the design of smart nanocarriers. Considerable efforts have been devoted to the design of molecular receptors capable of specific recognition of a wid...

  6. Bio-specific recognition and applications: from molecular to colloidal scales

    International Nuclear Information System (INIS)

    Baudry, Jean; Bertrand, Emanuel; Lequeux, Nicolas; Bibette, Jerome

    2004-01-01

    Biomolecules have the well-known ability to build reversible complexes. Indeed, antigens and antibodies or adhesion molecules are able to recognize one another with a strong affinity and a very high specificity. This paper first reviews the various techniques and related results about binding and unbinding, at the scale of a unique ligand/receptor couple. One important biotechnological application arising from these recognition phenomena concerns immuno-diagnosis, which is essentially based on the formation of these specific complexes. We show how the physics of colloids associated with the growing scientific background concerning molecular recognition helps in rationalizing and inventing new diagnostic strategies. Finally the concept of colloidal self-assembling systems as biosensors is presented as directly impacting the most important questions related to molecular recognition and their biotechnological implications. (topical review)

  7. Tunable Complex Stability in Surface Molecular Recognition Mediated by Self-Complementary Quadruple Hydrogen Bonds

    NARCIS (Netherlands)

    Zou, S(han); Zhang, Zhihong; Forch, Renate; Knoll, Wolfgang; Schönherr, Holger; Vancso, Gyula J.

    2003-01-01

    We show that surfaces modified with asymmetric 2-ureido-4[1H]-pyrimidinone-hydroxyalkane disulfide adsorbates exhibit efficient and controllable self-complementary molecular recognition of the pyrimidinone moieties. Two novel asymmetric 2-ureido-4[1H]-pyrimidinone-hydroxyalkane disulfide adsorbates,

  8. Molecular Recognition: Preparation and Characterization of Two Tripodal Anion Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Shokri, Alireza; Deng, Shihu; Wang, Xue B.; Kass, Steven R.

    2014-03-01

    Two new tripodal hydroxyl-based anion receptors (1 and 2) are reported and their molecular complexes with Cl–, H2PO4 –, and OAc– along with the (M–1)– ion of 1 were characterized by negative ion photoelectron spectroscopy in the gas phase and by binding constant determinations in four solvents (i.e., CDCl3, CD2Cl2, CD3COCD3, and CD3CN). An intramolecular hydrogen bond network (HBN) in hexaol 1 was found to diminish its binding whereas the triol 2 is the strongest aliphatic hydroxyl-based receptor to date.

  9. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

    Science.gov (United States)

    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  10. Machine learning and pattern recognition from surface molecular architectures.

    Science.gov (United States)

    Maksov, Artem; Ziatdinov, Maxim; Fujii, Shintaro; Sumpter, Bobby; Kalinin, Sergei

    The ability to utilize molecular assemblies as data storage devices requires capability to identify individual molecular states on a scale of thousands of molecules. We present a novel method of applying machine learning techniques for extraction of positional and rotational information from ultra-high vacuum scanning tunneling microscopy (STM) images and apply it to self-assembled monolayer of π-bowl sumanene molecules on gold. From density functional theory (DFT) simulations, we assume existence of distinct polar and multiple azimuthal rotational states. We use DFT-generated templates in conjunction with Markov Chain Monte Carlo (MCMC) sampler and noise modeling to create synthetic images representative of our model. We extract positional information of each molecule and use nearest neighbor criteria to construct a graph input to Markov Random Field (MRF) model to identify polar rotational states. We train a convolutional Neural Network (cNN) on a synthetic dataset and combine it with MRF model to classify molecules based on their azimuthal rotational state. We demonstrate effectiveness of such approach compared to other methods. Finally, we apply our approach to experimental images and achieve complete rotational class information extraction. This research was sponsored by the Division of Materials Sciences and Engineering, Office of Science, Basic Energy Sciences, US DOE.

  11. Conformational Smear Characterization and Binning of Single-Molecule Conductance Measurements for Enhanced Molecular Recognition.

    Science.gov (United States)

    Korshoj, Lee E; Afsari, Sepideh; Chatterjee, Anushree; Nagpal, Prashant

    2017-11-01

    Electronic conduction or charge transport through single molecules depends primarily on molecular structure and anchoring groups and forms the basis for a wide range of studies from molecular electronics to DNA sequencing. Several high-throughput nanoelectronic methods such as mechanical break junctions, nanopores, conductive atomic force microscopy, scanning tunneling break junctions, and static nanoscale electrodes are often used for measuring single-molecule conductance. In these measurements, "smearing" due to conformational changes and other entropic factors leads to large variances in the observed molecular conductance, especially in individual measurements. Here, we show a method for characterizing smear in single-molecule conductance measurements and demonstrate how binning measurements according to smear can significantly enhance the use of individual conductance measurements for molecular recognition. Using quantum point contact measurements on single nucleotides within DNA macromolecules, we demonstrate that the distance over which molecular junctions are maintained is a measure of smear, and the resulting variance in unbiased single measurements depends on this smear parameter. Our ability to identify individual DNA nucleotides at 20× coverage increases from 81.3% accuracy without smear analysis to 93.9% with smear characterization and binning (SCRIB). Furthermore, merely 7 conductance measurements (7× coverage) are needed to achieve 97.8% accuracy for DNA nucleotide recognition when only low molecular smear measurements are used, which represents a significant improvement over contemporary sequencing methods. These results have important implications in a broad range of molecular electronics applications from designing robust molecular switches to nanoelectronic DNA sequencing.

  12. Towards structural models of molecular recognition in olfactory receptors.

    Science.gov (United States)

    Afshar, M; Hubbard, R E; Demaille, J

    1998-02-01

    The G protein coupled receptors (GPCR) are an important class of proteins that act as signal transducers through the cytoplasmic membrane. Understanding the structure and activation mechanism of these proteins is crucial for understanding many different aspects of cellular signalling. The olfactory receptors correspond to the largest family of GPCRs. Very little is known about how the structures of the receptors govern the specificity of interaction which enables identification of particular odorant molecules. In this paper, we review recent developments in two areas of molecular modelling: methods for modelling the configuration of trans-membrane helices and methods for automatic docking of ligands into receptor structures. We then show how a subset of these methods can be combined to construct a model of a rat odorant receptor interacting with lyral for which experimental data are available. This modelling can help us make progress towards elucidating the specificity of interactions between receptors and odorant molecules.

  13. Phytosterol Recognition via Rationally Designed Molecularly Imprinted Polymers

    Directory of Open Access Journals (Sweden)

    Lachlan J. Schwarz

    2018-02-01

    Full Text Available Molecularly imprinted polymers (MIPs prepared via a semi-covalent imprinting strategy using stigmasteryl methacrylate as a polymerisable template have been evaluated by static binding methods for their ability to selectively capture other valuable phytosterol targets, including campesterol and brassicasterol. Design criteria based on molecular modelling procedures and interaction energy calculations were employed to aid the selection of the co-monomer type, as well as the choice of co-monomer:template ratios for the formation of the pre-polymerisation complex. These novel hybrid semi-covalently imprinted polymers employed N,N′-dimethylacryl-amide (N,N′-DMAAM as the functional co-monomer and displayed specific binding capacities in the range 5.2–5.9 mg sterol/g MIP resin. Their binding attributes and selectivities towards phytosterol compounds were significantly different to the corresponding MIPs prepared via non-covalent procedures or when compared to non-imprinted polymers. Cross-reactivity studies using stigmasterol, ergosterol, cholesterol, campesterol, and brassicasterol as single analytes revealed the importance of the A-ring C-3-β-hydroxyl group and the orientational preferences of the D-ring alkyl chain structures in their interaction in the templated cavity with the N,N′-dimethylamide functional groups of the MIP. Finally, to obtain useful quantities of both campersterol and brassicasterol for these investigations, improved synthetic routes have been developed to permit the conversion of the more abundant, lower cost stigmasterol via a reactive aldehyde intermediate to these other sterols.

  14. Adsorption and recognition characteristics of surface molecularly imprinted polymethacrylic acid/silica toward genistein.

    Science.gov (United States)

    Zhang, Yanyan; Gao, Baojiao; An, Fuqiang; Xu, Zeqing; Zhang, Tingting

    2014-09-12

    In this paper, on the basis of surface-initiated graft polymerization, a new surface molecular imprinting technique is established by molecular design. And molecularly imprinted polymer MIP-PMAA/SiO2 is successfully prepared with genistein as template. The adsorption and recognition characteristics of MIP-PMAA/SiO2 for genistein are studied in depth by using static method, dynamic method and competitive adsorption experiment. The experimental results show that MIP-PMAA/SiO2 possesses very strong adsorption affinity and specific recognition for genistein. The saturated adsorption capacity could reach to 0.36mmolg(-1). The selectivity coefficients relative to quercetin and rutin are 5.4 and 11.8, respectively. Besides, MIP-PMAA/SiO2 is regenerated easily and exhibits excellent reusability. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Recognition

    DEFF Research Database (Denmark)

    Gimmler, Antje

    2017-01-01

    In this article, I shall examine the cognitive, heuristic and theoretical functions of the concept of recognition. To evaluate both the explanatory power and the limitations of a sociological concept, the theory construction must be analysed and its actual productivity for sociological theory mus...

  16. Molecular architecture of protein-RNA recognition sites.

    Science.gov (United States)

    Barik, Amita; C, Nithin; Pilla, Smita P; Bahadur, Ranjit Prasad

    2015-01-01

    The molecular architecture of protein-RNA interfaces are analyzed using a non-redundant dataset of 152 protein-RNA complexes. We find that an average protein-RNA interface is smaller than an average protein-DNA interface but larger than an average protein-protein interface. Among the different classes of protein-RNA complexes, interfaces with tRNA are the largest, while the interfaces with the single-stranded RNA are the smallest. Significantly, RNA contributes more to the interface area than its partner protein. Moreover, unlike protein-protein interfaces where the side chain contributes less to the interface area compared to the main chain, the main chain and side chain contributions flipped in protein-RNA interfaces. We find that the protein surface in contact with the RNA in protein-RNA complexes is better packed than that in contact with the DNA in protein-DNA complexes, but loosely packed than that in contact with the protein in protein-protein complexes. Shape complementarity and electrostatic potential are the two major factors that determine the specificity of the protein-RNA interaction. We find that the H-bond density at the protein-RNA interfaces is similar with that of protein-DNA interfaces but higher than the protein-protein interfaces. Unlike protein-DNA interfaces where the deoxyribose has little role in intermolecular H-bonds, due to the presence of an oxygen atom at the 2' position, the ribose in RNA plays significant role in protein-RNA H-bonds. We find that besides H-bonds, salt bridges and stacking interactions also play significant role in stabilizing protein-nucleic acids interfaces; however, their contribution at the protein-protein interfaces is insignificant.

  17. Selecting Molecular Recognition. What Can Existing Aptamers Tell Us about Their Inherent Recognition Capabilities and Modes of Interaction?

    Directory of Open Access Journals (Sweden)

    Ralf Landgraf

    2012-05-01

    Full Text Available The use of nucleic acid derived aptamers has rapidly expanded since the introduction of SELEX in 1990. Nucleic acid aptamers have demonstrated their ability to target a broad range of molecules in ways that rival antibodies, but advances have been very uneven for different biochemical classes of targets, and clinical applications have been slow to emerge. What sets different aptamers apart from each other and from rivaling molecular recognition platforms, specifically proteins? What advantages do aptamers as a reagent class offer, and how do the chemical properties and selection procedures of aptamers influence their function? Do the building blocks of nucleic acid aptamers dictate inherent limitations in the nature of molecular targets, and do existing aptamers give us insight in how these challenges might be overcome? This review is written as an introduction for potential endusers of aptamer technology who are evaluating the advantages of aptamers as a versatile, affordable, yet highly expandable platform to target a broad range of biological processes or interactions.

  18. Magnetic deep eutectic solvents molecularly imprinted polymers for the selective recognition and separation of protein

    International Nuclear Information System (INIS)

    Liu, Yanjin; Wang, Yuzhi; Dai, Qingzhou; Zhou, Yigang

    2016-01-01

    A novel and facile magnetic deep eutectic solvents (DES) molecularly imprinted polymers (MIPs) for the selective recognition and separation of Bovine hemoglobin (BHb) was prepared. The new-type DES was adopted as the functional monomer which would bring molecular imprinted technology to a new direction. The amounts of DES were optimized. The obtained magnetic DES-MIPs were characterized with fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), elemental analysis and vibrating sample magnetometer (VSM). The results suggested that the imprinted polymers were successfully formed and possessed a charming magnetism. The maximum adsorption capability (Q_m_a_x) and dissociation constant (K_L) were analyzed by Langmuir isotherms (R"2 = 0.9983) and the value were estimated to be 175.44 mg/g and 0.035 mg/mL for the imprinted particles. And the imprinted particles showed a high imprinting factor of 4.77. In addition, the magnetic DES-MIPs presented outstanding recognition specificity and selectivity so that it can be utilized to separate template protein from the mixture of proteins and real samples. Last but not least, the combination of deep eutectic solvents and molecular imprinted technology in this paper provides a new perspective for the recognition and separation of proteins. - Highlights: • Combined green deep eutectic solvents (DES) and molecular imprinted technology in recognition and separation of proteins. • DES was adopted as a new-type functional monomer. • The obtained magnetic DES-MIPs can separate proteins rapidly by an external magnetic field. • Adsorption and selectivity properties were discussed.

  19. Sensors based on carbon nanotube field-effect transistors and molecular recognition approaches

    OpenAIRE

    Cid Salavert, Cristina Carlota

    2009-01-01

    The general objective of this thesis is to develop chemical sensors whose sensing capacities are based on the principle of molecular recognition and where the transduction is carried out by single-walled carbon nanotubes (SWCNT).The sensing device used is the carbon nanotube field-effect transistor (CNTFET). The new structure of the CNTFET allows nanotubes to be integrated at the surface of the devices, thus exploiting SWCNTs' sensitivity to changes in their environment. The functionalization...

  20. Magnetic deep eutectic solvents molecularly imprinted polymers for the selective recognition and separation of protein

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanjin [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Dai, Qingzhou [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Zhou, Yigang [Department of Microbiology, College of Basic Medicine, Central South University, Changsha, 410083 (China)

    2016-09-14

    A novel and facile magnetic deep eutectic solvents (DES) molecularly imprinted polymers (MIPs) for the selective recognition and separation of Bovine hemoglobin (BHb) was prepared. The new-type DES was adopted as the functional monomer which would bring molecular imprinted technology to a new direction. The amounts of DES were optimized. The obtained magnetic DES-MIPs were characterized with fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), elemental analysis and vibrating sample magnetometer (VSM). The results suggested that the imprinted polymers were successfully formed and possessed a charming magnetism. The maximum adsorption capability (Q{sub max}) and dissociation constant (K{sub L}) were analyzed by Langmuir isotherms (R{sup 2} = 0.9983) and the value were estimated to be 175.44 mg/g and 0.035 mg/mL for the imprinted particles. And the imprinted particles showed a high imprinting factor of 4.77. In addition, the magnetic DES-MIPs presented outstanding recognition specificity and selectivity so that it can be utilized to separate template protein from the mixture of proteins and real samples. Last but not least, the combination of deep eutectic solvents and molecular imprinted technology in this paper provides a new perspective for the recognition and separation of proteins. - Highlights: • Combined green deep eutectic solvents (DES) and molecular imprinted technology in recognition and separation of proteins. • DES was adopted as a new-type functional monomer. • The obtained magnetic DES-MIPs can separate proteins rapidly by an external magnetic field. • Adsorption and selectivity properties were discussed.

  1. Electrochemical sensor for dopamine based on a novel graphene-molecular imprinted polymers composite recognition element

    DEFF Research Database (Denmark)

    Mao, Yan; Bao, Yu; Gan, Shiyu

    2011-01-01

    A novel composite of graphene sheets/Congo red-molecular imprinted polymers (GSCR-MIPs) was synthesized through free radical polymerization (FRP) and applied as a molecular recognition element to construct dopamine (DA) electrochemical sensor. The template molecules (DA) were firstly absorbed...... at the GSCR surface due to their excellent affinity, and subsequently, selective copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) was further achieved at the GSCR surface. Potential scanning was presented to extract DA molecules from the imprinted polymers film...

  2. Environmental Molecular Sciences Laboratory Annual Report: Fiscal Year 2006

    Energy Technology Data Exchange (ETDEWEB)

    Foster, Nancy S.; Showalter, Mary Ann

    2007-03-23

    This report describes the activities and research performed at the Environmental Molecular Sciences Laboratory, a Department of Energy national scientific user facility at Pacific Northwest National Laboratory, during Fiscal Year 2006.

  3. Molecular mechanism for differential recognition of membrane phosphatidylserine by the immune regulatory receptor Tim4.

    Science.gov (United States)

    Tietjen, Gregory T; Gong, Zhiliang; Chen, Chiu-Hao; Vargas, Ernesto; Crooks, James E; Cao, Kathleen D; Heffern, Charles T R; Henderson, J Michael; Meron, Mati; Lin, Binhua; Roux, Benot; Schlossman, Mark L; Steck, Theodore L; Lee, Ka Yee C; Adams, Erin J

    2014-04-15

    Recognition of phosphatidylserine (PS) lipids exposed on the extracellular leaflet of plasma membranes is implicated in both apoptotic cell removal and immune regulation. The PS receptor T cell immunoglobulin and mucin-domain-containing molecule 4 (Tim4) regulates T-cell immunity via phagocytosis of both apoptotic (high PS exposure) and nonapoptotic (intermediate PS exposure) activated T cells. The latter population must be removed at lower efficiency to sensitively control immune tolerance and memory cell population size, but the molecular basis for how Tim4 achieves this sensitivity is unknown. Using a combination of interfacial X-ray scattering, molecular dynamics simulations, and membrane binding assays, we demonstrate how Tim4 recognizes PS in the context of a lipid bilayer. Our data reveal that in addition to the known Ca(2+)-coordinated, single-PS binding pocket, Tim4 has four weaker sites of potential ionic interactions with PS lipids. This organization makes Tim4 sensitive to PS surface concentration in a manner capable of supporting differential recognition on the basis of PS exposure level. The structurally homologous, but functionally distinct, Tim1 and Tim3 are significantly less sensitive to PS surface density, likely reflecting the differences in immunological function between the Tim proteins. These results establish the potential for lipid membrane parameters, such as PS surface density, to play a critical role in facilitating selective recognition of PS-exposing cells. Furthermore, our multidisciplinary approach overcomes the difficulties associated with characterizing dynamic protein/membrane systems to reveal the molecular mechanisms underlying Tim4's recognition properties, and thereby provides an approach capable of providing atomic-level detail to uncover the nuances of protein/membrane interactions.

  4. Recognition of Conformational Changes in β-Lactoglobulin by Molecularly Imprinted Thin Films

    Science.gov (United States)

    Turner, Nicholas W.; Liu, Xiao; Piletsky, Sergey A.; Hlady, Vladimir; Britt, David W.

    2008-01-01

    Pathogenesis in protein conformational diseases is initiated by changes in protein secondary structure. This molecular restructuring presents an opportunity for novel shape-based detection approaches, as protein molecular weight and chemistry are otherwise unaltered. Here we apply molecular imprinting to discriminate between distinct conformations of the model protein β-lactoglobulin (BLG). Thermal- and fluoro-alcohol-induced BLG isoforms were imprinted in thin films of 3-aminophenylboronic acid on quartz crystal microbalance chips. Enhanced rebinding of the template isoform was observed in all cases when compared to the binding of nontemplate isoforms over the concentration range of 1–100 µg mL−1. Furthermore, it was observed that the greater the changes in the secondary structure of the template protein the lower the binding of native BLG challenges to the imprint, suggesting a strong steric influence in the recognition system. This feasibility study is a first demonstration of molecular imprints for recognition of distinct conformations of the same protein. PMID:17665947

  5. Synthesis and Guest Recognition of Switchable Pt-Salphen Based Molecular Tweezers

    Directory of Open Access Journals (Sweden)

    Lorien Benda

    2018-04-01

    Full Text Available Molecular tweezers are artificial receptors that have an open cavity generated by two recognition units pre-organized by a spacer. Switchable molecular tweezers, using a stimuli-responsive spacer, are particularly appealing as prototypes of the molecular machines that combine mechanical motion and allosteric recognition properties. In this present study, the synthesis of switchable molecular tweezers composed of a central terpyridine unit substituted in 4,4″ positions by two Pt(II-salphen complexes is reported. The terpyridine ligand can be reversibly converted upon Zn(II coordination from a free ‘U’-shaped closed form to a coordinated ‘W’ open form. This new substitution pattern enables a reverse control of the mechanical motion compared to the previously reported 6,6″ substituted terpyridine-based tweezers. Guest binding studies with aromatic guests showed an intercalation of coronene in the cavity created by the Pt-salphen moieties in the closed conformation. The formation of 1:1 host-guest complex was investigated by a combination of NMR studies and DFT calculations.

  6. Molecular recognition in myxobacterial outer membrane exchange: functional, social and evolutionary implications.

    Science.gov (United States)

    Wall, Daniel

    2014-01-01

    Through cooperative interactions, bacteria can build multicellular communities. To ensure that productive interactions occur, bacteria must recognize their neighbours and respond accordingly. Molecular recognition between cells is thus a fundamental behaviour, and in bacteria important discoveries have been made. This MicroReview focuses on a recently described recognition system in myxobacteria that is governed by a polymorphic cell surface receptor called TraA. TraA regulates outer membrane exchange (OME), whereby myxobacterial cells transiently fuse their OMs to efficiently transfer proteins and lipids between cells. Unlike other transport systems, OME is rather indiscriminate in what OM goods are transferred. In contrast, the recognition of partnering cells is discriminatory and only occurs between cells that bear identical or closely related TraA proteins. Therefore TraA functions in kin recognition and, in turn, OME helps regulate social interactions between myxobacteria. Here, I discuss and speculate on the social and evolutionary implications of OME and suggest it helps to guide their transition from free-living cells into coherent and functional populations. © 2013 John Wiley & Sons Ltd.

  7. Elucidating Mechanisms of Molecular Recognition Between Human Argonaute and miRNA Using Computational Approaches

    KAUST Repository

    Jiang, Hanlun

    2016-12-06

    MicroRNA (miRNA) and Argonaute (AGO) protein together form the RNA-induced silencing complex (RISC) that plays an essential role in the regulation of gene expression. Elucidating the underlying mechanism of AGO-miRNA recognition is thus of great importance not only for the in-depth understanding of miRNA function but also for inspiring new drugs targeting miRNAs. In this chapter we introduce a combined computational approach of molecular dynamics (MD) simulations, Markov state models (MSMs), and protein-RNA docking to investigate AGO-miRNA recognition. Constructed from MD simulations, MSMs can elucidate the conformational dynamics of AGO at biologically relevant timescales. Protein-RNA docking can then efficiently identify the AGO conformations that are geometrically accessible to miRNA. Using our recent work on human AGO2 as an example, we explain the rationale and the workflow of our method in details. This combined approach holds great promise to complement experiments in unraveling the mechanisms of molecular recognition between large, flexible, and complex biomolecules.

  8. Molecularly imprinted titania nanoparticles for selective recognition and assay of uric acid

    Science.gov (United States)

    Mujahid, Adnan; Khan, Aimen Idrees; Afzal, Adeel; Hussain, Tajamal; Raza, Muhammad Hamid; Shah, Asma Tufail; uz Zaman, Waheed

    2015-06-01

    Molecularly imprinted titania nanoparticles are su ccessfully synthesized by sol-gel method for the selective recognition of uric acid. Atomic force microscopy is used to study the morphology of uric acid imprinted titania nanoparticles with diameter in the range of 100-150 nm. Scanning electron microscopy images of thick titania layer indicate the formation of fine network of titania nanoparticles with uniform distribution. Molecular imprinting of uric acid as well as its subsequent washing is confirmed by Fourier transformation infrared spectroscopy measurements. Uric acid rebinding studies reveal the recognition capability of imprinted particles in the range of 0.01-0.095 mmol, which is applicable in monitoring normal to elevated levels of uric acid in human blood. The optical shift (signal) of imprinted particles is six times higher in comparison with non-imprinted particles for the same concentration of uric acid. Imprinted titania particles have shown substantially reduced binding affinity toward interfering and structurally related substances, e.g. ascorbic acid and guanine. These results suggest the possible application of titania nanoparticles in uric acid recognition and quantification in blood serum.

  9. Elucidating Mechanisms of Molecular Recognition Between Human Argonaute and miRNA Using Computational Approaches.

    Science.gov (United States)

    Jiang, Hanlun; Zhu, Lizhe; Héliou, Amélie; Gao, Xin; Bernauer, Julie; Huang, Xuhui

    2017-01-01

    MicroRNA (miRNA) and Argonaute (AGO) protein together form the RNA-induced silencing complex (RISC) that plays an essential role in the regulation of gene expression. Elucidating the underlying mechanism of AGO-miRNA recognition is thus of great importance not only for the in-depth understanding of miRNA function but also for inspiring new drugs targeting miRNAs. In this chapter we introduce a combined computational approach of molecular dynamics (MD) simulations, Markov state models (MSMs), and protein-RNA docking to investigate AGO-miRNA recognition. Constructed from MD simulations, MSMs can elucidate the conformational dynamics of AGO at biologically relevant timescales. Protein-RNA docking can then efficiently identify the AGO conformations that are geometrically accessible to miRNA. Using our recent work on human AGO2 as an example, we explain the rationale and the workflow of our method in details. This combined approach holds great promise to complement experiments in unraveling the mechanisms of molecular recognition between large, flexible, and complex biomolecules.

  10. Two dimensional molecular electronics spectroscopy for molecular fingerprinting, DNA sequencing, and cancerous DNA recognition.

    Science.gov (United States)

    Rajan, Arunkumar Chitteth; Rezapour, Mohammad Reza; Yun, Jeonghun; Cho, Yeonchoo; Cho, Woo Jong; Min, Seung Kyu; Lee, Geunsik; Kim, Kwang S

    2014-02-25

    Laser-driven molecular spectroscopy of low spatial resolution is widely used, while electronic current-driven molecular spectroscopy of atomic scale resolution has been limited because currents provide only minimal information. However, electron transmission of a graphene nanoribbon on which a molecule is adsorbed shows molecular fingerprints of Fano resonances, i.e., characteristic features of frontier orbitals and conformations of physisorbed molecules. Utilizing these resonance profiles, here we demonstrate two-dimensional molecular electronics spectroscopy (2D MES). The differential conductance with respect to bias and gate voltages not only distinguishes different types of nucleobases for DNA sequencing but also recognizes methylated nucleobases which could be related to cancerous cell growth. This 2D MES could open an exciting field to recognize single molecule signatures at atomic resolution. The advantages of the 2D MES over the one-dimensional (1D) current analysis can be comparable to those of 2D NMR over 1D NMR analysis.

  11. Selective Nitrate Recognition by a Halogen‐Bonding Four‐Station [3]Rotaxane Molecular Shuttle

    Science.gov (United States)

    Barendt, Timothy A.; Docker, Andrew; Marques, Igor; Félix, Vítor

    2016-01-01

    Abstract The synthesis of the first halogen bonding [3]rotaxane host system containing a bis‐iodo triazolium‐bis‐naphthalene diimide four station axle component is reported. Proton NMR anion binding titration experiments revealed the halogen bonding rotaxane is selective for nitrate over the more basic acetate, hydrogen carbonate and dihydrogen phosphate oxoanions and chloride, and exhibits enhanced recognition of anions relative to a hydrogen bonding analogue. This elaborate interlocked anion receptor functions via a novel dynamic pincer mechanism where upon nitrate anion binding, both macrocycles shuttle from the naphthalene diimide stations at the periphery of the axle to the central halogen bonding iodo‐triazolium station anion recognition sites to form a unique 1:1 stoichiometric nitrate anion–rotaxane sandwich complex. Molecular dynamics simulations carried out on the nitrate and chloride halogen bonding [3]rotaxane complexes corroborate the 1H NMR anion binding results. PMID:27436297

  12. Integrated structural biology to unravel molecular mechanisms of protein-RNA recognition.

    Science.gov (United States)

    Schlundt, Andreas; Tants, Jan-Niklas; Sattler, Michael

    2017-04-15

    Recent advances in RNA sequencing technologies have greatly expanded our knowledge of the RNA landscape in cells, often with spatiotemporal resolution. These techniques identified many new (often non-coding) RNA molecules. Large-scale studies have also discovered novel RNA binding proteins (RBPs), which exhibit single or multiple RNA binding domains (RBDs) for recognition of specific sequence or structured motifs in RNA. Starting from these large-scale approaches it is crucial to unravel the molecular principles of protein-RNA recognition in ribonucleoprotein complexes (RNPs) to understand the underlying mechanisms of gene regulation. Structural biology and biophysical studies at highest possible resolution are key to elucidate molecular mechanisms of RNA recognition by RBPs and how conformational dynamics, weak interactions and cooperative binding contribute to the formation of specific, context-dependent RNPs. While large compact RNPs can be well studied by X-ray crystallography and cryo-EM, analysis of dynamics and weak interaction necessitates the use of solution methods to capture these properties. Here, we illustrate methods to study the structure and conformational dynamics of protein-RNA complexes in solution starting from the identification of interaction partners in a given RNP. Biophysical and biochemical techniques support the characterization of a protein-RNA complex and identify regions relevant in structural analysis. Nuclear magnetic resonance (NMR) is a powerful tool to gain information on folding, stability and dynamics of RNAs and characterize RNPs in solution. It provides crucial information that is complementary to the static pictures derived from other techniques. NMR can be readily combined with other solution techniques, such as small angle X-ray and/or neutron scattering (SAXS/SANS), electron paramagnetic resonance (EPR), and Förster resonance energy transfer (FRET), which provide information about overall shapes, internal domain

  13. Metal oxide nanosensors using polymeric membranes, enzymes and antibody receptors as ion and molecular recognition elements.

    Science.gov (United States)

    Willander, Magnus; Khun, Kimleang; Ibupoto, Zafar Hussain

    2014-05-16

    The concept of recognition and biofunctionality has attracted increasing interest in the fields of chemistry and material sciences. Advances in the field of nanotechnology for the synthesis of desired metal oxide nanostructures have provided a solid platform for the integration of nanoelectronic devices. These nanoelectronics-based devices have the ability to recognize molecular species of living organisms, and they have created the possibility for advanced chemical sensing functionalities with low limits of detection in the nanomolar range. In this review, various metal oxides, such as ZnO-, CuO-, and NiO-based nanosensors, are described using different methods (receptors) of functionalization for molecular and ion recognition. These functionalized metal oxide surfaces with a specific receptor involve either a complex formation between the receptor and the analyte or an electrostatic interaction during the chemical sensing of analytes. Metal oxide nanostructures are considered revolutionary nanomaterials that have a specific surface for the immobilization of biomolecules with much needed orientation, good conformation and enhanced biological activity which further improve the sensing properties of nanosensors. Metal oxide nanostructures are associated with certain unique optical, electrical and molecular characteristics in addition to unique functionalities and surface charge features which shows attractive platforms for interfacing biorecognition elements with effective transducing properties for signal amplification. There is a great opportunity in the near future for metal oxide nanostructure-based miniaturization and the development of engineering sensor devices.

  14. Metal Oxide Nanosensors Using Polymeric Membranes, Enzymes and Antibody Receptors as Ion and Molecular Recognition Elements

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2014-05-01

    Full Text Available The concept of recognition and biofunctionality has attracted increasing interest in the fields of chemistry and material sciences. Advances in the field of nanotechnology for the synthesis of desired metal oxide nanostructures have provided a solid platform for the integration of nanoelectronic devices. These nanoelectronics-based devices have the ability to recognize molecular species of living organisms, and they have created the possibility for advanced chemical sensing functionalities with low limits of detection in the nanomolar range. In this review, various metal oxides, such as ZnO-, CuO-, and NiO-based nanosensors, are described using different methods (receptors of functionalization for molecular and ion recognition. These functionalized metal oxide surfaces with a specific receptor involve either a complex formation between the receptor and the analyte or an electrostatic interaction during the chemical sensing of analytes. Metal oxide nanostructures are considered revolutionary nanomaterials that have a specific surface for the immobilization of biomolecules with much needed orientation, good conformation and enhanced biological activity which further improve the sensing properties of nanosensors. Metal oxide nanostructures are associated with certain unique optical, electrical and molecular characteristics in addition to unique functionalities and surface charge features which shows attractive platforms for interfacing biorecognition elements with effective transducing properties for signal amplification. There is a great opportunity in the near future for metal oxide nanostructure-based miniaturization and the development of engineering sensor devices.

  15. Molecular recognition of nucleotides in micelles and the development and expansion of a chemistry outreach program

    Science.gov (United States)

    Schechinger, Linda Sue

    I. To investigate the delivery of nucleotide-based drugs, we are studying molecular recognition of nucleotide derivatives in environments that are similar to cell membranes. The Nowick group previously discovered that membrane-like surfactant micelles tetradecyltrimethylammonium bromide (TTAB) micelle facilitate molecular of adenosine monophosphate (AMP) recognition. The micelles bind nucleotides by means of electrostatic interactions and hydrogen bonding. We observed binding by following 1H NMR chemical shift changes of unique hexylthymine protons upon addition of AMP. Cationic micelles are required for binding. In surfactant-free or sodium dodecylsulfate solutions, no hydrogen bonding is observed. These observations suggest that the cationic surfactant headgroups bind the nucleotide phosphate group, while the intramicellar base binds the nucleotide base. The micellar system was optimized to enhance binding and selectivity for adenosine nucleotides. The selectivity for adenosine and the number of phosphate groups attached to the adenosine were both investigated. Addition of cytidine, guanidine, or uridine monophosphates, results in no significant downfield shifting of the NH resonance. Selectivity for the phosphate is limited, since adenosine mono-, di-, and triphosphates all have similar binding constants. We successfully achieved molecular recognition of adenosine nucleotides in micellar environments. There is significant difference in the binding interactions between the adenosine nucleotides and three other natural nucleotides. II. The UCI Chemistry Outreach Program (UCICOP) addresses the declining interest of the nations youth for science. UCICOP brings fun and exciting chemistry experiments to local high schools, to remind students that science is fun and has many practical uses. Volunteer students and alumni of UCI perform the demonstrations using scripts and material provided by UCICOP. The preparation of scripts and materials is done by two coordinators

  16. Miniature Chemical Sensor Combining Molecular Recognition with Evanescent Wave Cavity Ring-Down Spectroscopy

    International Nuclear Information System (INIS)

    Pipino, Andrew C. R.; Meuse, Curtis W.

    2002-01-01

    To address the chemical sensing needs of DOE, a new class of chemical sensors is being developed that enables qualitative and quantitative, remote, real-time, optical diagnostics of chemical species in hazardous gas, liquid, and semi-solid phases by employing evanescent wave cavity ringdown spectroscopy (EW-CRDS). The sensitivity of EW-CRDS was demonstrated previously under Project No.60231. The objective of this project is to enhance the range of application and selectivity of the technique by combining EW-CRDS with refractive-index-sensitive nanoparticle optics, molecular recognition (MR) chemistry, and by utilizing the polarization-dependence of EW-CRDS. Research Progress and Implications

  17. In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element Specific for Bromacil

    Directory of Open Access Journals (Sweden)

    Ryan M. Williams

    2014-01-01

    Full Text Available Bromacil is a widely used herbicide that is known to contaminate environmental systems. Due to the hazards it presents and inefficient detection methods, it is necessary to create a rapid and efficient sensing device. Towards this end, we have utilized a stringent in vitro selection method to identify single-stranded DNA molecular recognition elements (MRE specific for bromacil. We have identified one MRE with high affinity (Kd=9.6 nM and specificity for bromacil compared to negative targets of selection and other pesticides. The selected ssDNA MRE will be useful as the sensing element in a field-deployable bromacil detection device.

  18. π-Cation Interactions in Molecular Recognition: Perspectives on Pharmaceuticals and Pesticides.

    Science.gov (United States)

    Liang, Zhibin; Li, Qing X

    2018-04-04

    The π-cation interaction that differs from the cation-π interaction is a valuable concept in molecular design of pharmaceuticals and pesticides. In this Perspective we present an up-to-date review (from 1995 to 2017) on bioactive molecules involving π-cation interactions with the recognition site, and categorize into systems of inhibitor-enzyme, ligand-receptor, ligand-transporter, and hapten-antibody. The concept of π-cation interactions offers use of π systems in a small molecule to enhance the binding affinity, specificity, selectivity, lipophilicity, bioavailability, and metabolic stability, which are physiochemical features desired for drugs and pesticides.

  19. Molecular recognition of malachite green by hemoglobin and their specific interactions: insights from in silico docking and molecular spectroscopy.

    Science.gov (United States)

    Peng, Wei; Ding, Fei; Peng, Yu-Kui; Sun, Ying

    2014-01-01

    Malachite green is an organic compound that can be widely used as a dyestuff for various materials; it has also emerged as a controversial agent in aquaculture. Since malachite green is proven to be carcinogenic and mutagenic, it may become a hazard to public health. For this reason, it is urgently required to analyze this controversial dye in more detail. In our current research, the interaction between malachite green and hemoglobin under physiological conditions was investigated by the methods of molecular modeling, fluorescence spectroscopy, circular dichroism (CD) as well as hydrophobic ANS displacement experiments. From the molecular docking, the central cavity of hemoglobin was assigned to possess high-affinity for malachite green, this result was corroborated by time-resolved fluorescence and hydrophobic ANS probe results. The recognition mechanism was found to be of static type, or rather the hemoglobin-malachite green complex formation occurred via noncovalent interactions such as π-π interactions, hydrogen bonds and hydrophobic interactions with an association constant of 10(4) M(-1). Moreover, the results also show that the spatial structure of the biopolymer was changed in the presence of malachite green with a decrease of the α-helix and increase of the β-sheet, turn and random coil suggesting protein damage, as derived from far-UV CD and three-dimensional fluorescence. Results of this work will help to further comprehend the molecular recognition of malachite green by the receptor protein and the possible toxicological profiles of other compounds, which are the metabolites and ramifications of malachite green.

  20. Molecular imprinting-chemiluminescence determination of trimethoprim using trimethoprim-imprinted polymer as recognition material.

    Science.gov (United States)

    He, Yunhua; Lu, Jiuru; Liu, Mei; Du, Jianxiu

    2005-07-01

    A new molecular imprinting-chemiluminescence method for the determination of trimethoprim was developed, in which trimethoprim-imprinted polymer was used as the molecular recognition material and the CL reaction of trimethoprim with potassium permanganate in acidic medium was used as the detection system. The CL intensity responds linearly to the concentration of trimethoprim within the 5.0 x 10(-8)-5.0 x 10(-6) g mL(-1) range (r= 0.9983) with a detection limit of 2 x 10(-8) g mL(-1). The relative standard deviation for the determination of 1.0 x 10(-7) g mL(-1) trimethoprim solutions is 4.8% (n= 9). The method has been applied to the determination of trimethoprim in pharmaceutical preparations and body fluids, and satisfactory results were obtained.

  1. RECOGNITION DYNAMICS OF ESCHERICHIA COLI THIOREDOXIN PROBED USING MOLECULAR DYNAMICS AND BINDING FREE ENERGY CALCULATIONS

    Directory of Open Access Journals (Sweden)

    M. S. Shahul Hameed

    2016-03-01

    Full Text Available E. coli thioredoxin has been regarded as a hub protein as it interacts with, and regulates, numerous target proteins involved in a wide variety of cellular processes. Thioredoxin can form complexes with a variety of target proteins with a wide range of affinity, using a consensus binding surface. In this study an attempt to deduce the molecular basis for the observed multispecificity of E. coli thioredoxin has been made. In this manuscript it has been shown that structural plasticity, adaptable and exposed hydrophobic binding surface, surface electrostatics, closely clustered multiple hot spot residues and conformational changes brought about by the redox status of the protein have been shown to account for the observed multispecificity and molecular recognition of thioredoxin. Dynamical differences between the two redox forms of the enzyme have also been studied to account for their differing interactions with some target proteins.

  2. Investigating the binding behaviour of two avidin-based testosterone binders using molecular recognition force spectroscopy.

    Science.gov (United States)

    Rangl, Martina; Leitner, Michael; Riihimäki, Tiina; Lehtonen, Soili; Hytönen, Vesa P; Gruber, Hermann J; Kulomaa, Markku; Hinterdorfer, Peter; Ebner, Andreas

    2014-02-01

    Molecular recognition force spectroscopy, a biosensing atomic force microscopy technique allows to characterise the dissociation of ligand-receptor complexes at the molecular level. Here, we used molecular recognition force spectroscopy to study the binding capability of recently developed testosterone binders. The two avidin-based proteins called sbAvd-1 and sbAvd-2 are expected to bind both testosterone and biotin but differ in their binding behaviour towards these ligands. To explore the ligand binding and dissociation energy landscape of these proteins, we tethered biotin or testosterone to the atomic force microscopy probe while the testosterone-binding protein was immobilized on the surface. Repeated formation and rupture of the ligand-receptor complex at different pulling velocities allowed determination of the loading rate dependence of the complex-rupturing force. In this way, we obtained the molecular dissociation rate (k(off)) and energy landscape distances (x(β)) of the four possible complexes: sbAvd-1-biotin, sbAvd-1-testosterone, sbAvd-2-biotin and sbAvd-2-testosterone. It was found that the kinetic off-rates for both proteins and both ligands are similar. In contrast, the x(β) values, as well as the probability of complex formations, varied considerably. In addition, competitive binding experiments with biotin and testosterone in solution differ significantly for the two testosterone-binding proteins, implying a decreased cross-reactivity of sbAvd-2. Unravelling the binding behaviour of the investigated testosterone-binding proteins is expected to improve their usability for possible sensing applications. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Magnetic-graphene based molecularly imprinted polymer nanocomposite for the recognition of bovine hemoglobin.

    Science.gov (United States)

    Guo, Junxia; Wang, Yuzhi; Liu, Yanjin; Zhang, Cenjin; Zhou, Yigang

    2015-11-01

    The protein imprinted technique combining surface imprinting and nanomaterials has been an attractive strategy for recognition and rapid separation of proteins. In this work, magnetic-graphene (MG) was chosen as the supporting substrate for the magnetic nanomaterials, which served to absorb the targeting imprinting molecules, bovine hemoglobin (BHb). Acryl amide (AAm) with a high affinity to BHb and N,N'- methylenebisacrylamide (MBA) were selected as the functional monomer and cross-linking agent, respectively. After in-situ polymerization, the proposed magnetic-graphene based molecularly imprinted polymer (MG-MIP) was obtained with a further extraction step of imprinted BHb. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), raman spectroscopy(RS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were employed to characterize the resulted MG-MIP. The maximum adsorption capability (Qmax) was determined by Langmuir Isotherm Plots and was 186.73 mg/g for imprinted nanomaterials (MIP) with an imprinting factor of 1.96. The selectivity of MG-MIP was investigated by using several proteins that are different in molecular mass and isoelectric points as the reference. The results showed that the shape memory effect of imprinted cavities, the size of proteins and the charge effect of proteins were the major factors for the selective recognition. The proposed method was also employed to specifically capture BHb from a binary protein mixture. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Higher Desolvation Energy Reduces Molecular Recognition in Multi-Drug Resistant HIV-1 Protease

    Directory of Open Access Journals (Sweden)

    Ladislau C. Kovari

    2012-05-01

    Full Text Available Designing HIV-1 protease inhibitors that overcome drug-resistance is still a challenging task. In this study, four clinical isolates of multi-drug resistant HIV-1 proteases that exhibit resistance to all the US FDA-approved HIV-1 protease inhibitors and also reduce the substrate recognition ability were examined. A multi-drug resistant HIV-1 protease isolate, MDR 769, was co-crystallized with the p2/NC substrate and the mutated CA/p2 substrate, CA/p2 P1’F. Both substrates display different levels of molecular recognition by the wild-type and multi-drug resistant HIV-1 protease. From the crystal structures, only limited differences can be identified between the wild-type and multi-drug resistant protease. Therefore, a wild-type HIV-1 protease and four multi-drug resistant HIV-1 proteases in complex with the two peptides were modeled based on the crystal structures and examined during a 10 ns-molecular dynamics simulation. The simulation results reveal that the multi-drug resistant HIV-1 proteases require higher desolvation energy to form complexes with the peptides. This result suggests that the desolvation of the HIV-1 protease active site is an important step of protease-ligand complex formation as well as drug resistance. Therefore, desolvation energy could be considered as a parameter in the evaluation of future HIV-1 protease inhibitor candidates.

  5. Molecularly imprinted poly (methacrylamide-co-methacrylic acid) composite membranes for recognition of curcumin

    International Nuclear Information System (INIS)

    Wang Ping; Hu Wenming; Su Weike

    2008-01-01

    In this study, molecularly imprinted poly (methacrylamide-co-methacrylic acid) composite membranes with different ratio of methacrylamide (MAM) versus methacrylic acid (MAA) were prepared via UV initiated photo-copolymerization on the commercial filter paper. Curcumin was chosen as the template molecule. Infra-red (IR) spectroscopy was used to study the binding mechanism between the imprinted sites and the templates. The morphology of the resultant membranes was visualized by scanning electron microscopy (SEM). Static equilibrium binding and recognition properties of the imprinted composite membranes to curcumin (cur-I) and its analogues demethoxycurcumin (cur-II) or bisdemethoxycurcumin (cur-III) were tested. The results showed that curcumin-imprinted membranes had the best recognition ability to curcumin compared to its analogues. From the results, the biggest selectivity factor of α cur-I/cur-II and α cur-I/cur-III were 1.50 and 5.94, and they were obtained from the composite membranes in which MAM/MAA were 1:4 and 0:1, respectively. The results of this study implied that the molecularly imprinted composite membranes could be used as separation membranes for curcumin enrichment

  6. Recognition of damage-associated, nucleic acid-related molecular patterns during inflammation and vaccination

    Directory of Open Access Journals (Sweden)

    Nao eJounai

    2013-01-01

    Full Text Available All mammalian cells are equipped with large numbers of sensors for protection from various sorts of invaders, who, in turn, are equipped with molecules containing pathogen-associated molecular patterns (PAMPs. Once these sensors recognize non-self antigens containing PAMPs, various physiological responses including inflammation are induced to eliminate the pathogens. However, the host sometimes suffers from chronic infection or continuous injuries, resulting in production of self-molecules containing damage-associated molecular patterns (DAMPs. DAMPs are also responsible for the elimination of pathogens, but promiscuous recognition of DAMPs through sensors against PAMPs has been reported. Accumulation of DAMPs leads to massive inflammation and continuous production of DAMPs; that is, a vicious circle leading to the development of autoimmune disease. From a vaccinological point of view, the accurate recognition of both PAMPs and DAMPs is important for vaccine immunogenicity, because vaccine adjuvants are composed of several PAMPs and/or DAMPs, which are also associated with severe adverse events after vaccination. Here, we review as the roles of PAMPs and DAMPs upon infection with pathogens or inflammation, and the sensors responsible for recognizing them, as well as their relationship with the development of autoimmune disease or the immunogenicity of vaccines.

  7. Preparation and recognition of surface molecularly imprinted core-shell microbeads for protein in aqueous solutions

    International Nuclear Information System (INIS)

    Lu Yan; Yan Changling; Gao Shuyan

    2009-01-01

    In this paper, a surface molecular imprinting technique was reported for preparing core-shell microbeads of protein imprinting, and bovine hemoglobin or bovine serum albumin were used as model proteins for studying the imprinted core-shell microbeads. 3-Aminophenylboronic acid (APBA) was polymerized onto the surface of polystyrene microbead in the presence of the protein templates to create protein-imprinted core-shell microbeads. The various samples were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) methods. The effect of pH on rebinding of the template hemoglobin, the specific binding and selective recognition were studied for the imprinted microbeads. The results show that the bovine hemoglobin-imprinted core-shell microbeads were successfully created. The shell was a sort of imprinted thin films with porous structure and larger surface areas. The imprinted microbeads have good selectivity for templates and high stability. Due to the recognition sites locating at or closing to the surface, these imprinted microbeads have good property of mass-transport. Unfortunately, the imprint technology was not successfully applied to imprinting bovine serum albumin (BSA).

  8. Selective Nitrate Recognition by a Halogen-Bonding Four-Station [3]Rotaxane Molecular Shuttle.

    Science.gov (United States)

    Barendt, Timothy A; Docker, Andrew; Marques, Igor; Félix, Vítor; Beer, Paul D

    2016-09-05

    The synthesis of the first halogen bonding [3]rotaxane host system containing a bis-iodo triazolium-bis-naphthalene diimide four station axle component is reported. Proton NMR anion binding titration experiments revealed the halogen bonding rotaxane is selective for nitrate over the more basic acetate, hydrogen carbonate and dihydrogen phosphate oxoanions and chloride, and exhibits enhanced recognition of anions relative to a hydrogen bonding analogue. This elaborate interlocked anion receptor functions via a novel dynamic pincer mechanism where upon nitrate anion binding, both macrocycles shuttle from the naphthalene diimide stations at the periphery of the axle to the central halogen bonding iodo-triazolium station anion recognition sites to form a unique 1:1 stoichiometric nitrate anion-rotaxane sandwich complex. Molecular dynamics simulations carried out on the nitrate and chloride halogen bonding [3]rotaxane complexes corroborate the (1) H NMR anion binding results. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  9. Molecularly imprinted polymer based on chemiluminescence imaging for the chiral recognition of dansyl-phenylalanine.

    Science.gov (United States)

    Wang, Li; Zhang, Zhujun; Huang, Lianggao

    2008-03-01

    A new molecularly imprinted polymer (MIP)-chemiluminescence (CL) imaging detection approach towards chiral recognition of dansyl-phenylalanine (Phe) is presented. The polymer microspheres were synthesized using precipitation polymerization with dansyl-L-Phe as template. Polymer microspheres were immobilized in microtiter plates (96 wells) using poly(vinyl alcohol) (PVA) as glue. The analyte was selectively adsorbed on the MIP microspheres. After washing, the bound fraction was quantified based on peroxyoxalate chemiluminescence (PO-CL) analysis. In the presence of dansyl-Phe, bis(2,4,6-trichlorophenyl)oxalate (TCPO) reacted with hydrogen peroxide (H2O2) to emit chemiluminescence. The signal was detected and quantified with a highly sensitive cooled charge-coupled device (CCD). Influencing factors were investigated and optimized in detail. Control experiments using capillary electrophoresis showed that there was no significant difference between the proposed method and the control method at a confidence level of 95%. The method can perform 96 independent measurements simultaneously in 30 min and the limits of detection (LODs) for dansyl-L-Phe and dansyl-D-Phe were 0.025 micromol L(-1) and 0.075 micromol L(-1) (3sigma), respectively. The relative standard deviation (RSD) for 11 parallel measurements of dansyl-L-Phe (0.78 micromol L(-1)) was 8%. The results show that MIP-based CL imaging can become a useful analytical technology for quick chiral recognition.

  10. Preparation and recognition of surface molecularly imprinted core-shell microbeads for protein in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yan, E-mail: yanlu2001@sohu.com [College of Chemistry and Environmental Science, Henan Normal University, 46 Jlanshe Road, Xinxiang 453007 (China); Yan Changling; Gao Shuyan [College of Chemistry and Environmental Science, Henan Normal University, 46 Jlanshe Road, Xinxiang 453007 (China)

    2009-04-01

    In this paper, a surface molecular imprinting technique was reported for preparing core-shell microbeads of protein imprinting, and bovine hemoglobin or bovine serum albumin were used as model proteins for studying the imprinted core-shell microbeads. 3-Aminophenylboronic acid (APBA) was polymerized onto the surface of polystyrene microbead in the presence of the protein templates to create protein-imprinted core-shell microbeads. The various samples were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) methods. The effect of pH on rebinding of the template hemoglobin, the specific binding and selective recognition were studied for the imprinted microbeads. The results show that the bovine hemoglobin-imprinted core-shell microbeads were successfully created. The shell was a sort of imprinted thin films with porous structure and larger surface areas. The imprinted microbeads have good selectivity for templates and high stability. Due to the recognition sites locating at or closing to the surface, these imprinted microbeads have good property of mass-transport. Unfortunately, the imprint technology was not successfully applied to imprinting bovine serum albumin (BSA).

  11. Electrospun Nanofibers from a Tricyanofuran-Based Molecular Switch for Colorimetric Recognition of Ammonia Gas.

    Science.gov (United States)

    Khattab, Tawfik A; Abdelmoez, Sherif; Klapötke, Thomas M

    2016-03-14

    A chromophore based on tricyanofuran (TCF) with a hydrazone (H) recognition moiety was developed. Its molecular-switching performance is reversible and has differential sensitivity towards aqueous ammonia at comparable concentrations. Nanofibers were fabricated from the TCF-H chromophore by electrospinning. The film fabricated from these nanofibers functions as a solid-state optical chemosensor for probing ammonia vapor. Recognition of ammonia vapor occurs by proton transfer from the hydrazone fragment of the chromophore to the ammonia nitrogen atom and is facilitated by the strongly electron withdrawing TCF fragment. The TCF-H chromophore was added to a solution of poly(acrylic acid), which was electrospun to obtain a nanofibrous sensor device. The morphology of the nanofibrous sensor was determined by SEM, which showed that nanofibers with a diameter range of 200-450 nm formed a nonwoven mat. The resultant nanofibrous sensor showed very good sensitivity in ammonia-vapor detection. Furthermore, very good reversibility and short response time were also observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Protein-Templated Fragment Ligations-From Molecular Recognition to Drug Discovery.

    Science.gov (United States)

    Jaegle, Mike; Wong, Ee Lin; Tauber, Carolin; Nawrotzky, Eric; Arkona, Christoph; Rademann, Jörg

    2017-06-19

    Protein-templated fragment ligation is a novel concept to support drug discovery and can help to improve the efficacy of protein ligands. Protein-templated fragment ligations are chemical reactions between small molecules ("fragments") utilizing a protein's surface as a reaction vessel to catalyze the formation of a protein ligand with increased binding affinity. The approach exploits the molecular recognition of reactive small-molecule fragments by proteins both for ligand assembly and for the identification of bioactive fragment combinations. In this way, chemical synthesis and bioassay are integrated in one single step. This Review discusses the biophysical basis of reversible and irreversible fragment ligations and gives an overview of the available methods to detect protein-templated ligation products. The chemical scope and recent applications as well as future potential of the concept in drug discovery are reviewed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Design, preparation, surface recognition properties, and characteristics of icariin molecularly imprinted polymers

    Directory of Open Access Journals (Sweden)

    Xiaohe Jia

    2015-12-01

    Full Text Available Icariin molecularly imprinted polymers (MIPs were prepared by precipitation polymerization. Prior to the polymerization, computer simulation was performed to sketchily choose the suitable functional monomer and the corresponding polymerization solvent. The optimized synthesis parameters, including the functional monomer acrylamide, the mixture of methanol and acetonitrile (V:V = 3:1 as the polymerization solvent, and the reaction molar ratio (1:6:80 of template molecule, functional monomer and cross-linker, were respectively obtained by single factor analysis and orthogonal design methods. The results of the adsorption experiments showed that the resultant MIPs exhibited good adsorption and recognition abilities to icariin. Scatchard analysis illustrated that the homogeneous binding sites only for icariin molecules were formed in the prepared MIPs.

  14. Computational modeling on the recognition of the HRE motif by HIF-1: molecular docking and molecular dynamics studies.

    Science.gov (United States)

    Sokkar, Pandian; Sathis, Vani; Ramachandran, Murugesan

    2012-05-01

    Hypoxia inducible factor-1 (HIF-1) is a bHLH-family transcription factor that controls genes involved in glycolysis, angiogenesis, migration, as well as invasion factors that are important for tumor progression and metastasis. HIF-1, a heterodimer of HIF-1α and HIF-1β, binds to the hypoxia responsive element (HRE) present in the promoter regions of hypoxia responsive genes, such as vascular endothelial growth factor (VEGF). Neither the structure of free HIF-1 nor that of its complex with HRE is available. Computational modeling of the transcription factor-DNA complex has always been challenging due to their inherent flexibility and large conformational space. The present study aims to model the interaction between the DNA-binding domain of HIF-1 and HRE. Experiments showed that rigid macromolecular docking programs (HEX and GRAMM-X) failed to predict the optimal dimerization of individually modeled HIF-1 subunits. Hence, the HIF-1 heterodimer was modeled based on the phosphate system positive regulatory protein (PHO4) homodimer. The duplex VEGF-DNA segment containing HRE with flanking nucleotides was modeled in the B form and equilibrated via molecular dynamics (MD) simulation. A rigid docking approach was used to predict the crude binding mode of HIF-1 dimer with HRE, in which the putative contacts were found to be present. An MD simulation (5 ns) of the HIF-1-HRE complex in explicit water was performed to account for its flexibility and to optimize its interactions. All of the conserved amino acid residues were found to play roles in the recognition of HRE. The present work, which sheds light on the recognition of HRE by HIF-1, could be beneficial in the design of peptide or small molecule therapeutics that can mimic HIF-1 and bind with the HRE sequence.

  15. Preparation of a magnetic molecularly imprinted polymer for selective recognition of rhodamine B

    International Nuclear Information System (INIS)

    Liu, Xiuying; Yu, Dan; Yu, Yingchao; Ji, Shujuan

    2014-01-01

    Graphical abstract: A novel material based on the use of magnetic Fe3O4 nanoparticles coated with MMIP for preconcentration and determination of RhB in real samples prior to fluorospectrophotometry was developed. - Highlights: • A novel rhodamine B magnetic molecularly imprinted polymer by using Fe 3 O 4 magnetite as the magnetically susceptible component was synthesized. • The MMIP had rapid adsorption and high selectivity towards rhodamine B. • Rhodamine B can be extracted selectively by MMIP from real samples. • The method provides the advantages of short analysis time and high sensitivity. - Abstract: A novel magnetic molecularly imprinted polymer (MMIP) was developed as an adsorbent to selectively remove rhodamine B from real samples. The polymer was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermo-gravimetric analysis. Static adsorption, kinetic adsorption, and selective recognition experiments were also performed to investigate the specific adsorption equilibrium, kinetics, and selective recognition ability of the MMIP. The MMIPs had outstanding thermal stability, large adsorption capacity, and high competitive selectivity. When they were used as dispersed solid-phase extraction adsorbents in real samples, rhodamine B recovery was 79.97–81.88% and 75.56–79.74% in intra-day and inter-day reproducibility experiments with relative standard deviations lower than 2.62% and 4.28%, respectively. Extraction was optimized for yield and efficiency. Precision, accuracy, and linear working range were determined under optimal experimental conditions. The limits of detection and quantification were 1.05 and 3.49 μg L −1 , respectively. These results suggest MMIPs may be used for determination of rhodamine B in real samples

  16. Engineering responsive polymer building blocks with host-guest molecular recognition for functional applications.

    Science.gov (United States)

    Hu, Jinming; Liu, Shiyong

    2014-07-15

    CONSPECTUS: All living organisms and soft matter are intrinsically responsive and adaptive to external stimuli. Inspired by this fact, tremendous effort aiming to emulate subtle responsive features exhibited by nature has spurred the invention of a diverse range of responsive polymeric materials. Conventional stimuli-responsive polymers are constructed via covalent bonds and can undergo reversible or irreversible changes in chemical structures, physicochemical properties, or both in response to a variety of external stimuli. They have been imparted with a variety of emerging applications including drug and gene delivery, optical sensing and imaging, diagnostics and therapies, smart coatings and textiles, and tissue engineering. On the other hand, in comparison with molecular chemistry held by covalent bonds, supramolecular chemistry built on weak and reversible noncovalent interactions has emerged as a powerful and versatile strategy for materials fabrication due to its facile accessibility, extraordinary reversibility and adaptivity, and potent applications in diverse fields. Typically involving more than one type of noncovalent interactions (e.g., hydrogen bonding, metal coordination, hydrophobic association, electrostatic interactions, van der Waals forces, and π-π stacking), host-guest recognition refers to the formation of supramolecular inclusion complexes between two or more entities connected together in a highly controlled and cooperative manner. The inherently reversible and adaptive nature of host-guest molecular recognition chemistry, stemming from multiple noncovalent interactions, has opened up a new platform to construct novel types of stimuli-responsive materials. The introduction of host-guest chemistry not only enriches the realm of responsive materials but also confers them with promising new applications. Most intriguingly, the integration of responsive polymer building blocks with host-guest recognition motifs will endow the former with

  17. Gelation or molecular recognition; is the bis-(α,β-dihydroxy esters motif an omnigelator?

    Directory of Open Access Journals (Sweden)

    Peter C. Griffiths

    2010-11-01

    Full Text Available Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy esters are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration. A range of neutron techniques – in particular small-angle neutron scattering (SANS – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS are warranted, and it is hoped that this work will stimulate others to pursue this line of research.

  18. Oxidation-specific epitopes are danger-associated molecular patterns recognized by pattern recognition receptors of innate immunity

    DEFF Research Database (Denmark)

    Miller, Yury I; Choi, Soo-Ho; Wiesner, Philipp

    2011-01-01

    are a major target of innate immunity, recognized by a variety of "pattern recognition receptors" (PRRs). By analogy with microbial "pathogen-associated molecular patterns" (PAMPs), we postulate that host-derived, oxidation-specific epitopes can be considered to represent "danger (or damage......)-associated molecular patterns" (DAMPs). We also argue that oxidation-specific epitopes present on apoptotic cells and their cellular debris provided the primary evolutionary pressure for the selection of such PRRs. Furthermore, because many PAMPs on microbes share molecular identity and/or mimicry with oxidation...

  19. Study on the mechanism of chiral recognition with molecularly imprinted polymers

    International Nuclear Information System (INIS)

    Lu Yan; Li Chenxi; Zhang Hesheng; Liu Xiaohang

    2003-01-01

    This study aimed at elucidating the chiral recognition mechanism with molecularly imprinted polymers (MIPs) in aqueous environment. The system used ethylene glycol dimethacrylate (EGDMA), methacrylic acid (MAA), and 4-L-phenylalanylamino-pyridine (4-L-PheNHPy) as the cross-linking monomer, functional monomer and template, respectively, to assemble the imprinted polymer. A self-assembly mechanism, which includes the pre-organizing functional monomers around template before polymerization process, was proposed. This mechanism was supported by 1 H NMR titration test. Interactions between functional monomer and template were observed using UV-Vis spectroscopy of solutions of these components as well. These studies indicated a 1:2 molecular complex dominantly formed between 4-L-PheNHPy and MAA. Association constant was estimated to be 97,000 M -2 . Based on these results, a model mainly involving two-spot interaction was proposed evolving from our reported concept of exact placement of functional group. Ionic interaction between the primary amino group of 4-L-PheNHPy and carboxylic acid group inside the microcavity on MIPs was believed to play a predominate role in the enantioselectivity as supported by the observation of the relationship between the retention factor of 4-L-PheNHPy and the pH of mobile phase. While thermodynamic study at different pH revealed that, the interaction between the pyridyl group of 4-L-PheNHPy and the carboxylic acid group on the MIPs is also strong, implying that it also plays a profound role in determining the highly chiral selectivity of MIPs

  20. Mapping molecular adhesion sites inside SMIL coated capillaries using atomic force microscopy recognition imaging

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, Michael [Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz (Austria); Stock, Lorenz G. [Division of Chemistry and Bioanalytics, Department of Molecular Biology, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg (Austria); Christian Doppler Laboratory for Innovative Tools for the Characterization of Biosimilars, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg (Austria); Traxler, Lukas [Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz (Austria); Leclercq, Laurent [Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier (France); Bonazza, Klaus; Friedbacher, Gernot [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, 1060 Vienna (Austria); Cottet, Hervé [Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier (France); Stutz, Hanno [Division of Chemistry and Bioanalytics, Department of Molecular Biology, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg (Austria); Christian Doppler Laboratory for Innovative Tools for the Characterization of Biosimilars, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg (Austria); Ebner, Andreas, E-mail: andreas.ebner@jku.at [Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz (Austria)

    2016-08-03

    Capillary zone electrophoresis (CZE) is a powerful analytical technique for fast and efficient separation of different analytes ranging from small inorganic ions to large proteins. However electrophoretic resolution significantly depends on the coating of the inner capillary surface. High technical efforts like Successive Multiple Ionic Polymer Layer (SMIL) generation have been taken to develop stable coatings with switchable surface charges fulfilling the requirements needed for optimal separation. Although the performance can be easily proven in normalized test runs, characterization of the coating itself remains challenging. Atomic force microscopy (AFM) allows for topographical investigation of biological and analytical relevant surfaces with nanometer resolution and yields information about the surface roughness and homogeneity. Upgrading the scanning tip to a molecular biosensor by adhesive molecules (like partly inverted charged molecules) allows for performing topography and recognition imaging (TREC). As a result, simultaneously acquired sample topography and adhesion maps can be recorded. We optimized this technique for electrophoresis capillaries and investigated the charge distribution of differently composed and treated SMIL coatings. By using the positively charged protein avidin as a single molecule sensor, we compared these SMIL coatings with respect to negative charges, resulting in adhesion maps with nanometer resolution. The capability of TREC as a functional investigation technique at the nanoscale was successfully demonstrated. - Highlights: • SMIL coating allows generation of homogeneous ultra-flat surfaces. • Molecular electrostatic adhesion forces can be determined in the inner wall of CZE capillary with picoNewton accuracy. • Topographical images and simultaneously acquired adhesion maps yield morphological and chemical information at the nanoscale.

  1. Leukemia-Associated Mutations in Nucleophosmin Alter Recognition by CRM1: Molecular Basis of Aberrant Transport.

    Directory of Open Access Journals (Sweden)

    Igor Arregi

    Full Text Available Nucleophosmin (NPM is a nucleocytoplasmic shuttling protein, normally enriched in nucleoli, that performs several activities related to cell growth. NPM mutations are characteristic of a subtype of acute myeloid leukemia (AML, where mutant NPM seems to play an oncogenic role. AML-associated NPM mutants exhibit altered subcellular traffic, being aberrantly located in the cytoplasm of leukoblasts. Exacerbated export of AML variants of NPM is mediated by the nuclear export receptor CRM1, and due, in part, to a mutationally acquired novel nuclear export signal (NES. To gain insight on the molecular basis of NPM transport in physiological and pathological conditions, we have evaluated the export efficiency of NPM in cells, and present new data indicating that, in normal conditions, wild type NPM is weakly exported by CRM1. On the other hand, we have found that AML-associated NPM mutants efficiently form complexes with CRM1HA (a mutant CRM1 with higher affinity for NESs, and we have quantitatively analyzed CRM1HA interaction with the NES motifs of these mutants, using fluorescence anisotropy and isothermal titration calorimetry. We have observed that the affinity of CRM1HA for these NESs is similar, which may help to explain the transport properties of the mutants. We also describe NPM recognition by the import machinery. Our combined cellular and biophysical studies shed further light on the determinants of NPM traffic, and how it is dramatically altered by AML-related mutations.

  2. Helicase Dependent Isothermal Amplification of DNA and RNA using Self-Avoiding Molecular Recognition Systems

    Science.gov (United States)

    Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M.; Hoshika, Shuichi; Frye, Carole; Benner, Steven A.

    2015-01-01

    Assays that target DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low resource environments, requiring equipment and power that may not be available in these environments. However, isothermal procedures that avoid thermal cycling are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a “self avoiding molecular recognition system” (SAMRS) eliminates these artifacts to give clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3′-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, something difficult to achieve with HDA using standard primers. This shows that SAMRS-HDA is a more versatile approach than standard HDA with a broader applicability for xNA-targeted diagnostics and research. PMID:25953623

  3. Molecular Recognition of Corticotropin releasing Factor by Its G protein-coupled Receptor CRFR1

    Energy Technology Data Exchange (ETDEWEB)

    Pioszak, Augen A.; Parker, Naomi R.; Suino-Powell, Kelly; Xu, H. Eric (Van Andel)

    2009-01-15

    The bimolecular interaction between corticotropin-releasing factor (CRF), a neuropeptide, and its type 1 receptor (CRFR1), a class B G-protein-coupled receptor (GPCR), is crucial for activation of the hypothalamic-pituitary-adrenal axis in response to stress, and has been a target of intense drug design for the treatment of anxiety, depression, and related disorders. As a class B GPCR, CRFR1 contains an N-terminal extracellular domain (ECD) that provides the primary ligand binding determinants. Here we present three crystal structures of the human CRFR1 ECD, one in a ligand-free form and two in distinct CRF-bound states. The CRFR1 ECD adopts the alpha-beta-betaalpha fold observed for other class B GPCR ECDs, but the N-terminal alpha-helix is significantly shorter and does not contact CRF. CRF adopts a continuous alpha-helix that docks in a hydrophobic surface of the ECD that is distinct from the peptide-binding site of other class B GPCRs, thereby providing a basis for the specificity of ligand recognition between CRFR1 and other class B GPCRs. The binding of CRF is accompanied by clamp-like conformational changes of two loops of the receptor that anchor the CRF C terminus, including the C-terminal amide group. These structural studies provide a molecular framework for understanding peptide binding and specificity by the CRF receptors as well as a template for designing potent and selective CRFR1 antagonists for therapeutic applications.

  4. Biopolymeric receptor for peptide recognition by molecular imprinting approach—Synthesis, characterization and application

    International Nuclear Information System (INIS)

    Singh, Lav Kumar; Singh, Monika; Singh, Meenakshi

    2014-01-01

    The present work is focused on the development of a biocompatible zwitterionic hydrogel for various applications in analytical chemistry. Biopolymer chitosan was derivatized to obtain a series of zwitterionic hydrogel samples. Free amino groups hanging on the biopolymeric chain were reacted with γ-butyrolactone to quaternize the N-centers of polymeric chain. N,N-methylene-bis-acrylamide acts as a crosslinker via Michael-type addition in the subsequent step and facilitated gelation of betainized chitosan. These biopolymeric hydrogel samples were fully characterized by FTIR, 1 H NMR, 13 C NMR spectra, SEM and XRD. Hydrogels were further characterized for their swelling behavior at varying parameters. The extent of swelling was perceived to be dictated by solvent composition such as pH, ionic strength and temperature. This valuable polymeric format is herein chosen to design an artificial receptor for dipeptide ‘carnosine’, which has adequate societal significance to be analytically determined, by molecular imprinting. Electrostatic interactions along with complementary H-bonding and other hydrophobic interactions inducing additional synergetic effect between the template (carnosine) and the imprinted polymer led to the formation of imprinted sites. The MIP was able to selectively and specifically take up carnosine from aqueous solution quantitatively. Thus prepared MIPs were characterized by FTIR spectroscopy, SEM providing evidence for the quality and quantity of imprinted gels. The binding studies showed that the MIP illustrated good recognition for carnosine as compared to non-imprinted polymers (NIPs). Detection limit was estimated as 3.3 μg mL −1 . Meanwhile, selectivity experiments demonstrated that imprinted gel had a high affinity to carnosine in the presence of close structural analogues (interferrants). - Highlights: • Development of a biocompatible zwitterionic hydrogel • A series of chitosan-derived zwitterionic hydrogel samples • Polymeric

  5. Molecularly imprinted polymer based on MWCNT-QDs as fluorescent biomimetic sensor for specific recognition of target protein

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Zhaoqiang [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Annie Bligh, S.W. [Department of Life Sciences, Faculty of Science and Technology, University of Westminster, 115 New Cavendish Street, London W1W 6UW (United Kingdom); Tao, Lei; Quan, Jing [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Nie, Huali, E-mail: niehuali@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Zhu, Limin, E-mail: lzhu@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Gong, Xiao [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China)

    2015-03-01

    A novel molecularly imprinted optosensing material based on multi-walled carbon nanotube-quantum dots (MWCNT-QDs) has been designed and synthesized for its high selectivity, sensitivity and specificity in the recognition of a target protein bovine serum albumin (BSA). Molecularly imprinted polymer coated MWCNT-QDs using BSA as the template (BMIP-coated MWCNT-QDs) exhibits a fast mass-transfer speed with a response time of 25 min. It is found that the BSA as a target protein can significantly quench the luminescence of BMIP-coated MWCNT-QDs in a concentration-dependent manner that is best described by a Stern–Volmer equation. The K{sub SV} for BSA is much higher than bovine hemoglobin and lysozyme, implying a highly selective recognition of the BMIP-coated MWCNT-QDs to BSA. Under optimal conditions, the relative fluorescence intensity of BMIP-coated MWCNT-QDs decreases linearly with the increasing target protein BSA in the concentration range of 5.0 × 10{sup −7}–35.0 × 10{sup −7} M with a detection limit of 80 nM. - Highlights: • A novel fluorescent biomimetic sensor based on MWCNT-QDs was designed. • The sensor exhibited a fast mass-transfer speed with a response time of 25 min. • The sensor possessed a highly selective recognition to BSA.

  6. Assembling of G-strands into novel tetra-molecular parallel G4-DNA nanostructures using avidin-biotin recognition.

    Science.gov (United States)

    Borovok, Natalia; Iram, Natalie; Zikich, Dragoslav; Ghabboun, Jamal; Livshits, Gideon I; Porath, Danny; Kotlyar, Alexander B

    2008-09-01

    We describe a method for the preparation of novel long (hundreds of nanometers), uniform, inter-molecular G4-DNA molecules composed of four parallel G-strands. The only long continuous G4-DNA reported so far are intra-molecular structures made of a single G-strand. To enable a tetra-molecular assembly of the G-strands we developed a novel approach based on avidin-biotin biological recognition. The steps of the G4-DNA production include: (i) Enzymatic synthesis of long poly(dG)-poly(dC) molecules with biotinylated poly(dG)-strand; (ii) Formation of a complex between avidin-tetramer and four biotinylated poly(dG)-poly(dC) molecules; (iii) Separation of the poly(dC) strands from the poly(dG)-strands, which are connected to the avidin; (iv) Assembly of the four G-strands attached to the avidin into tetra-molecular G4-DNA. The average contour length of the formed structures, as measured by AFM, is equal to that of the initial poly(dG)-poly(dC) molecules, suggesting a tetra-molecular mechanism of the G-strands assembly. The height of tetra-molecular G4-nanostructures is larger than that of mono-molecular G4-DNA molecules having similar contour length. The CD spectra of the tetra- and mono-molecular G4-DNA are markedly different, suggesting different structural organization of these two types of molecules. The tetra-molecular G4-DNA nanostructures showed clear electrical polarizability. This suggests that they may be useful for molecular electronics.

  7. Molecular Recognition of PTS-1 Cargo Proteins by Pex5p: Implications for Protein Mistargeting in Primary Hyperoxaluria

    Directory of Open Access Journals (Sweden)

    Noel Mesa-Torres

    2015-02-01

    Full Text Available Peroxisomal biogenesis and function critically depends on the import of cytosolic proteins carrying a PTS1 sequence into this organelle upon interaction with the peroxin Pex5p. Recent structural studies have provided important insights into the molecular recognition of cargo proteins by Pex5p. Peroxisomal import is a key feature in the pathogenesis of primary hyperoxaluria type 1 (PH1, where alanine:glyoxylate aminotransferase (AGT undergoes mitochondrial mistargeting in about a third of patients. Here, we study the molecular recognition of PTS1 cargo proteins by Pex5p using oligopeptides and AGT variants bearing different natural PTS1 sequences, and employing an array of biophysical, computational and cell biology techniques. Changes in affinity for Pex5p (spanning over 3–4 orders of magnitude reflect different thermodynamic signatures, but overall bury similar amounts of molecular surface. Structure/energetic analyses provide information on the contribution of ancillary regions and the conformational changes induced in Pex5p and the PTS1 cargo upon complex formation. Pex5p stability in vitro is enhanced upon cargo binding according to their binding affinities. Moreover, we provide evidence that the rational modulation of the AGT: Pex5p binding affinity might be useful tools to investigate mistargeting and misfolding in PH1 by pulling the folding equilibria towards the native and peroxisomal import competent state.

  8. Rapid determination of 239Pu in urine samples using molecular recognition technology product AnaLigRPu-02 gel

    International Nuclear Information System (INIS)

    Silvia Dulanska; Boris Remenec; Jan Bilohuscin; Miroslav Labaska; Bianka Horvathova; Andrej Matel

    2013-01-01

    This paper describes the use of IBC's AnaLig R Pu-02 molecular recognition technology product to effectively and selectively pre-concentrate, separate and recover plutonium from urine samples. This method uses two-stage column separations consisting of two different commercial products, Eichrom's Pre-filter Material and AnaLig R Pu-02 resin from IBC Advanced Technologies. By eliminating the co-precipitation techniques and the ashing steps to remove residual organics, the analysis time was reduced significantly. The method was successfully tested by adding known activities of reference solutions of 242 Pu and 239 Pu to urine samples. (author)

  9. Molecular Recognition in the Oxidation of Catechols by Dicobalt-BISDIEN Dioxygen Complexes

    Science.gov (United States)

    1992-01-30

    Recognition in the Oxidation of Catechols by Dicobalt-RISDIEN Dioxygen Complexes Lizete F S Cezar and Bruno Szpoganicz Departamento de Quimica ...bridged bi- nuclear Co(II)-BISDIEN dioxygen complexes; Co20 2 LCat2 + is the bivalent form, and Co20 2 (OH)LCat + and Co 20 2 (OH)2 Cat° are hydroxo

  10. Molecular recognition of halogen-tagged aromatic VOCs at the air-silicon interface.

    Science.gov (United States)

    Condorelli, Guglielmo G; Motta, Alessandro; Favazza, Maria; Gurrieri, Ettore; Betti, Paolo; Dalcanale, Enrico

    2010-01-14

    Selective and reversible complexation of halogen-tagged aromatic VOCs by a quinoxaline cavitand-decorated Si surface is demonstrated. The specific host-guest interactions of the Si-bonded receptors are proved to be responsible of the surface recognition properties, while extracavity non specific adsorptions are totally suppressed compared to the bulk material.

  11. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)-adenine derivatives.

    Science.gov (United States)

    Stojković, Marijana Radić; Skugor, Marko; Dudek, Lukasz; Grolik, Jarosław; Eilmes, Julita; Piantanida, Ivo

    2014-01-01

    An investigation of the interactions of two novel and several known DBTAA-adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA-propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure-activity relation for the studied series of compounds showed that the essential structural features for the ICD recognition are a) the presence of DNA-binding appendages (adenine side chain and positively charged side chain) on both DBTAA side chains, and b) the presence of a short propyl linker, which does not support intramolecular aromatic stacking between DBTAA and adenine. The observed AT-DNA-ICD pattern differs from previously reported ss-DNA (poly dT) ICD recognition by a strong negative ICD band at 350 nm, which allows for the dynamic differentiation between ss-DNA (poly dT) and coupled ds-AT-DNA.

  12. The role of the molecular chaperone heat shock protein A2 (HSPA2 in regulating human sperm-egg recognition

    Directory of Open Access Journals (Sweden)

    Brett Nixon

    2015-01-01

    Full Text Available One of the most common lesions present in the spermatozoa of human infertility patients is an idiopathic failure of sperm-egg recognition. Although this unique cellular interaction can now be readily by-passed by assisted reproductive strategies such as intracytoplasmic sperm injection (ICSI, recent large-scale epidemiological studies have encouraged the cautious use of this technology and highlighted the need for further research into the mechanisms responsible for defective sperm-egg recognition. Previous work in this field has established that the sperm domains responsible for oocyte interaction are formed during spermatogenesis prior to being dynamically modified during epididymal maturation and capacitation in female reproductive tract. While the factors responsible for the regulation of these sequential maturational events are undoubtedly complex, emerging research has identified the molecular chaperone, heat shock protein A2 (HSPA2, as a key regulator of these events in human spermatozoa. HSPA2 is a testis-enriched member of the 70 kDa heat shock protein family that promotes the folding, transport, and assembly of protein complexes and has been positively correlated with in vitro fertilization (IVF success. Furthermore, reduced expression of HSPA2 from the human sperm proteome leads to an impaired capacity for cumulus matrix dispersal, sperm-egg recognition and fertilization following both IVF and ICSI. In this review, we consider the evidence supporting the role of HSPA2 in sperm function and explore the potential mechanisms by which it is depleted in the spermatozoa of infertile patients. Such information offers novel insights into the molecular mechanisms governing sperm function.

  13. Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes

    Directory of Open Access Journals (Sweden)

    Chuanjun Liu

    2017-02-01

    Full Text Available The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM sensor arrays based on molecularly imprinted sol-gel (MISG materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL; nonanal (NAL and bezaldehyde (BAL. The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS and tetrabutoxytitanium (TBOT. Aminopropyltriethoxysilane (APT; diethylaminopropyltrimethoxysilane (EAP and trimethoxy-phenylsilane (TMP were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA; nonanoic acid (NA and benzoic acid (BA were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA; multivariate analysis of covariance (MANCOVA and hierarchical cluster analysis (HCA. The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP effect and the matrix

  14. Molecular recognition of H3/H4 histone tails by the tudor domains of JMJD2A: a comparative molecular dynamics simulations study.

    Directory of Open Access Journals (Sweden)

    Musa Ozboyaci

    Full Text Available BACKGROUND: Histone demethylase, JMJD2A, specifically recognizes and binds to methylated lysine residues at histone H3 and H4 tails (especially trimethylated H3K4 (H3K4me3, trimethylated H3K9 (H3K9me3 and di,trimethylated H4K20 (H4K20me2, H4K20me3 via its tandem tudor domains. Crystal structures of JMJD2A-tudor binding to H3K4me3 and H4K20me3 peptides are available whereas the others are not. Complete picture of the recognition of the four histone peptides by the tandem tudor domains yet remains to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We report a detailed molecular dynamics simulation and binding energy analysis of the recognition of JMJD2A-tudor with four different histone tails. 25 ns fully unrestrained molecular dynamics simulations are carried out for each of the bound and free structures. We investigate the important hydrogen bonds and electrostatic interactions between the tudor domains and the peptide molecules and identify the critical residues that stabilize the complexes. Our binding free energy calculations show that H4K20me2 and H3K9me3 peptides have the highest and lowest affinity to JMJD2A-tudor, respectively. We also show that H4K20me2 peptide adopts the same binding mode with H4K20me3 peptide, and H3K9me3 peptide adopts the same binding mode with H3K4me3 peptide. Decomposition of the enthalpic and the entropic contributions to the binding free energies indicate that the recognition of the histone peptides is mainly driven by favourable van der Waals interactions. Residue decomposition of the binding free energies with backbone and side chain contributions as well as their energetic constituents identify the hotspots in the binding interface of the structures. CONCLUSION: Energetic investigations of the four complexes suggest that many of the residues involved in the interactions are common. However, we found two receptor residues that were related to selective binding of the H3 and H4 ligands. Modifications or mutations

  15. Foundations for a syntatic pattern recognition system for genomic DNA sequences. [Annual] report, 1 December 1991--31 March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Searles, D.B.

    1993-03-01

    The goal of the proposed work is the creation of a software system that will perform sophisticated pattern recognition and related functions at a level of abstraction and with expressive power beyond current general-purpose pattern-matching systems for biological sequences; and with a more uniform language, environment, and graphical user interface, and with greater flexibility, extensibility, embeddability, and ability to incorporate other algorithms, than current special-purpose analytic software.

  16. Fabrication of micromagnetic beads with molecular recognition/electron-transfer peptides for the sensing of ovalbumin

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, Kazuharu, E-mail: kzsuga@maebashi-it.ac.jp [Maebashi Institute of Technology, Gunma, 371-0816 (Japan); Kuramitz, Hideki [Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering for Research, University of Toyama, Toyama, 930-8555 (Japan); Shinohara, Hiroki [Maebashi Institute of Technology, Gunma, 371-0816 (Japan)

    2017-03-15

    Electrochemical sensing of ovalbumin (OVA) was performed using magnetic beads with OVA recognition (RNRCKGTDVQAW)/electron-transfer (YYYYC) peptides. The focus of this study was to construct a highly sensitive and regenerative tool for OVA detection based on the interaction between a protein and peptide-1(RNRCKGTDVQAWYYYYC). The peptide-1 was introduced to the bead through four types of cross-linking reagents. Magnetic beads of different sizes with N-(6-maleimidocaproyloxy)sulfosuccinimide (Sulfo-EMCS) were also prepared. An oxidation peak due to tyrosine residues at 0.65 V depended on the distance of the electron-transfer peptide from the bead surface and on the surface area of the magnetic beads that contacted the electrode surface. The response of the electro-transfer peptide moiety was decreased because the protein was accumulated via the recognition peptide on the beads. When using Sulfo-EMCS and beads that were 6.0–6.9 μm in diameter, the calibration curve of OVA was linear and ranged from 8.0 × 10{sup −13} to 2.0 × 10{sup −11} M. To regenerate the magnetic beads, the measurements were achieved after removal of the OVA using a denaturing reagent. When OVA was added to fetal bovine serum containing a complex matrix, OVA was recovered at a rate of 98–100%. Consequently, these magnetic beads could be a powerful tool for the sensing of OVA in real samples. - Highlights: • Ovalbumin recognition/electron-transfer peptides were immobilized on magnetic beads. • The accumulation of the protein through the peptides on the beads caused the change of electrode response. • The magnetic beads could be reused for sensing of ovalbumin.

  17. Analogies Between Digital Radio and Chemical Orthogonality as a Method for Enhanced Analysis of Molecular Recognition Events

    Directory of Open Access Journals (Sweden)

    Sang-Hun Lee

    2008-02-01

    Full Text Available Acoustic wave biosensors are a real-time, label-free biosensor technology, which have been exploited for the detection of proteins and cells. One of the conventional biosensor approaches involves the immobilization of a monolayer of antibodies onto the surface of the acoustic wave device for the detection of a specific analyte. The method described within includes at least two immobilizations of two different antibodies onto the surfaces of two separate acoustic wave devices for the detection of several analogous analytes. The chemical specificity of the molecular recognition event is achieved by virtue of the extremely high (nM to pM binding affinity between the antibody and its antigen. In a standard ELISA (Enzyme-Linked ImmunoSorbent Assay test, there are multiple steps and the end result is a measure of what is bound so tightly that it does not wash away easily. The fact that this “gold standard” is very much not real time, masks the dance that is the molecular recognition event. X-Ray Crystallographer, Ian Wilson, demonstrated more than a decade ago that antibodies undergo conformational change during a binding event[1, 2]. Further, it is known in the arena of immunochemistry that some antibodies exhibit significant cross-reactivity and this is widely termed antibody promiscuity. A third piece of the puzzle that we will exploit in our system of acoustic wave biosensors is the notion of chemical orthogonality. These three biochemical constructs, the dance, antibody promiscuity and chemical orthogonality will be combined in this paper with the notions of Int. J. Mol. Sci. 2008, 9 155 in-phase (I and quadrature (Q signals from digital radio to manifest an approach to molecular recognition that allows a level of discrimination and analysis unobtainable without the aggregate. As an example we present experimental data on the detection of TNT, RDX, C4, ammonium nitrate and musk oil from a system of antibody-coated acoustic

  18. Aptamer-Based Molecular Recognition of Lysergamine, Metergoline and Small Ergot Alkaloids

    Directory of Open Access Journals (Sweden)

    Johan Robbens

    2012-12-01

    Full Text Available Ergot alkaloids are mycotoxins produced by fungi of the genus Claviceps, which infect cereal crops and grasses. The uptake of ergot alkaloid contaminated cereal products can be lethal to humans and animals. For food safety assessment, analytical techniques are currently used to determine the presence of ergot alkaloids in food and feed samples. However, the number of samples which can be analyzed is limited, due to the cost of the equipment and the need for skilled personnel. In order to compensate for the lack of rapid tests for the detection of ergot alkaloids, the aim of this study was to develop a specific recognition element for ergot alkaloids, which could be further applied to produce a colorimetric reaction in the presence of these toxins. As recognition elements, single-stranded DNA ligands were selected by using an iterative selection procedure named SELEX, i.e., Systematic Evolution of Ligands by EXponential enrichment. After several selection cycles, the resulting aptamers were cloned and sequenced. A surface plasmon resonance analysis enabled determination of the dissociation constants of the complexes of aptamers and lysergamine. Dissociation constants in the nanomolar range were obtained with three selected aptamers. One of the selected aptamers, having a dissociation constant of 44 nM, was linked to gold nanoparticles and it was possible to produce a colorimetric reaction in the presence of lysergamine. This system could also be applied to small ergot alkaloids in an ergot contaminated flour sample.

  19. Molecular cloning and characterization of a short peptidoglycan recognition protein from silkworm Bombyx mori.

    Science.gov (United States)

    Yang, P-J; Zhan, M-Y; Ye, C; Yu, X-Q; Rao, X-J

    2017-12-01

    Peptidoglycan is the major bacterial component recognized by the insect immune system. Peptidoglycan recognition proteins (PGRPs) are a family of pattern-recognition receptors that recognize peptidoglycans and modulate innate immune responses. Some PGRPs retain N-acetylmuramoyl-L-alanine amidase (Enzyme Commission number: 3.5.1.28) activity to hydrolyse bacterial peptidoglycans. Others have lost the enzymatic activity and work only as immune receptors. They are all important modulators for innate immunity. Here, we report the cloning and functional analysis of PGRP-S4, a short-form PGRP from the domesticated silkworm, Bombyx mori. The PGRP-S4 gene encodes a protein of 199 amino acids with a signal peptide and a PGRP domain. PGRP-S4 was expressed in the fat body, haemocytes and midgut. Its expression level was significantly induced by bacterial challenges in the midgut. The recombinant PGRP-S4 bound bacteria and different peptidoglycans. In addition, it inhibited bacterial growth and hydrolysed an Escherichia coli peptidoglycan in the presence of Zn 2+ . Scanning electron microscopy showed that PGRP-S4 disrupted the bacterial cell surface. PGRP-S4 further increased prophenoloxidase activation caused by peptidoglycans. Taken together, our data suggest that B. mori PGRP-S4 has multiple functions in immunity. © 2017 The Royal Entomological Society.

  20. Molecular Pathways for Immune Recognition of Preproinsulin Signal Peptide in Type 1 Diabetes.

    Science.gov (United States)

    Kronenberg-Versteeg, Deborah; Eichmann, Martin; Russell, Mark A; de Ru, Arnoud; Hehn, Beate; Yusuf, Norkhairin; van Veelen, Peter A; Richardson, Sarah J; Morgan, Noel G; Lemberg, Marius K; Peakman, Mark

    2018-04-01

    The signal peptide region of preproinsulin (PPI) contains epitopes targeted by HLA-A-restricted (HLA-A0201, A2402) cytotoxic T cells as part of the pathogenesis of β-cell destruction in type 1 diabetes. We extended the discovery of the PPI epitope to disease-associated HLA-B*1801 and HLA-B*3906 (risk) and HLA-A*1101 and HLA-B*3801 (protective) alleles, revealing that four of six alleles present epitopes derived from the signal peptide region. During cotranslational translocation of PPI, its signal peptide is cleaved and retained within the endoplasmic reticulum (ER) membrane, implying it is processed for immune recognition outside of the canonical proteasome-directed pathway. Using in vitro translocation assays with specific inhibitors and gene knockout in PPI-expressing target cells, we show that PPI signal peptide antigen processing requires signal peptide peptidase (SPP). The intramembrane protease SPP generates cytoplasm-proximal epitopes, which are transporter associated with antigen processing (TAP), ER-luminal epitopes, which are TAP independent, each presented by different HLA class I molecules and N-terminal trimmed by ER aminopeptidase 1 for optimal presentation. In vivo, TAP expression is significantly upregulated and correlated with HLA class I hyperexpression in insulin-containing islets of patients with type 1 diabetes. Thus, PPI signal peptide epitopes are processed by SPP and loaded for HLA-guided immune recognition via pathways that are enhanced during disease pathogenesis. © 2018 by the American Diabetes Association.

  1. Investigations into the origin of the molecular recognition of several adenosine deaminase inhibitors.

    Science.gov (United States)

    Gillerman, Irina; Fischer, Bilha

    2011-01-13

    Inhibitors of adenosine deaminase (ADA, EC 3.5.4.4) are potential therapeutic agents for the treatment of various health disorders. Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities. We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity. We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA. However, several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity. Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K(i) values of 25, 22, 6, and 3 μM, respectively. We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters. A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor. In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant.

  2. Effective Use of Molecular Recognition in Gas Sensing: Results from Acoustic Wave and In-Situ FTIR Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bodenhofer, K,; Gopel, W.; Hierlemann, A.; Ricco, A.J.

    1998-12-09

    To probe directly the analyte/film interactions that characterize molecular recognition in gas sensors, we recorded changes to the in-situ surface vibrational spectra of specifically fictionalized surface acoustic wave (SAW) devices concurrently with analyte exposure and SAW measurement of the extent of sorption. Fourier-lmnsform infrared external- reflectance spectra (FTIR-ERS) were collected from operating 97-MH2 SAW delay lines during exposure to a range of analytes as they interacted with thin-film coatings previously shown to be selective: cyclodextrins for chiral recognition, Ni-camphorates for Lewis bases such as pyridine and organophosphonates, and phthalocyanines for aromatic compounds. In most cases where specific chemical interactions-metal coordination, "cage" compound inclusion, or z stacking-were expected, analyte dosing caused distinctive changes in the IR spectr~ together with anomalously large SAW sensor responses. In contrast, control experiments involving the physisorption of the same analytes by conventional organic polymers did not cause similar changes in the IR spectra, and the SAW responses were smaller. For a given conventional polymer, the partition coefficients (or SAW sensor signals) roughly followed the analyte fraction of saturation vapor pressure. These SAW/FTIR results support earlier conclusions derived from thickness-shear mode resonator data.

  3. Molecular basis for the wide range of affinity found in Csr/Rsm protein-RNA recognition.

    Science.gov (United States)

    Duss, Olivier; Michel, Erich; Diarra dit Konté, Nana; Schubert, Mario; Allain, Frédéric H-T

    2014-04-01

    The carbon storage regulator/regulator of secondary metabolism (Csr/Rsm) type of small non-coding RNAs (sRNAs) is widespread throughout bacteria and acts by sequestering the global translation repressor protein CsrA/RsmE from the ribosome binding site of a subset of mRNAs. Although we have previously described the molecular basis of a high affinity RNA target bound to RsmE, it remains unknown how other lower affinity targets are recognized by the same protein. Here, we have determined the nuclear magnetic resonance solution structures of five separate GGA binding motifs of the sRNA RsmZ of Pseudomonas fluorescens in complex with RsmE. The structures explain how the variation of sequence and structural context of the GGA binding motifs modulate the binding affinity for RsmE by five orders of magnitude (∼10 nM to ∼3 mM, Kd). Furthermore, we see that conformational adaptation of protein side-chains and RNA enable recognition of different RNA sequences by the same protein contributing to binding affinity without conferring specificity. Overall, our findings illustrate how the variability in the Csr/Rsm protein-RNA recognition allows a fine-tuning of the competition between mRNAs and sRNAs for the CsrA/RsmE protein.

  4. Tragacanth gum-based nanogel as a superparamagnetic molecularly imprinted polymer for quercetin recognition and controlled release.

    Science.gov (United States)

    Hemmati, Khadijeh; Masoumi, Arameh; Ghaemy, Mousa

    2016-01-20

    A highly selective magnetic molecularly imprinted polymer (MMIP) with core-shell structure has been synthesized by a sol-gel process composed of Tragacanth Gum (TG) crosslinker, Fe3O4/SiO2 nanoparticles, and N-vinyl imidazole(VI) functional monomer in the presence of template Quercetin (QC). Different techniques including scanning electron microscopy (SEM), SEM-energy dispersive spectroscopy (SEM-EDS), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM) were used to verify the successful synthesis of MIP on the surface of Fe3O4/SiO2 nanoparticles. The swelling behavior of MMIP, its recognition and selectivity for QC and structural analog, Catechin (CT), were tested and compared with magnetic non imprinted polymer (MNIP). MMIP adsorbs the template drug quickly and equilibrium could be reached in 2h. The mechanism for adsorption was found to follow the Langmuir model with the maximum capacity of 175.43 mg g(-1). The MMIP indicated excellent recognition and binding affinity toward QC, selectivity factor (ɛ) relative to CT was 2.16. Finally, the MMIP was evaluated as a drug delivery device by performing in vitro release studies in PBS. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Electrochemical impedimetric sensor based on molecularly imprinted polymers/sol-gel chemistry for methidathion organophosphorous insecticide recognition.

    Science.gov (United States)

    Bakas, Idriss; Hayat, Akhtar; Piletsky, Sergey; Piletska, Elena; Chehimi, Mohamed M; Noguer, Thierry; Rouillon, Régis

    2014-12-01

    We report here a novel method to detect methidathion organophosphorous insecticides. The sensing platform was architected by the combination of molecularly imprinted polymers and sol-gel technique on inexpensive, portable and disposable screen printed carbon electrodes. Electrochemical impedimetric detection technique was employed to perform the label free detection of the target analyte on the designed MIP/sol-gel integrated platform. The selection of the target specific monomer by electrochemical impedimetric methods was consistent with the results obtained by the computational modelling method. The prepared electrochemical MIP/sol-gel based sensor exhibited a high recognition capability toward methidathion, as well as a broad linear range and a low detection limit under the optimized conditions. Satisfactory results were also obtained for the methidathion determination in waste water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Molecular imprinting polymer electrosensor based on gold nanoparticles for theophylline recognition and determination

    International Nuclear Information System (INIS)

    Kan, X.; Liu, T.; Zhou, H.; Li, C.; Fang, B.

    2010-01-01

    An electrochemical sensor for theophylline (ThPh) was prepared by electropolymerizing o-phenylenediamine on a glassy carbon electrode in the presence of ThPh via cyclic voltammetry, followed by deposition of gold nanoparticles using a potentiostatic method. The effects of pH, ratio between template molecule and monomer, number of cycles for electropolymerization, and of the solution for extraction were optimized. The current of the electro-active model system hexacyanoferrate(III) and hexacyanoferrate(IV) decreased linearly with successive addition of ThPh in the concentration range between 4. 0 x 10 -7 ∼ 1. 5 x 10 -5 mol.L -1 and 2. 4 x 10 -4 ∼ 3. 4 x 10 -3 mol.L -1 , with a detection limit of 1. 0 x 10 -7 mol.L -1 . The sensor has an excellent recognition capability for ThPh compared to structurally related molecules, can be regenerated and is stable. (author)

  7. Application of Machine Learning tools to recognition of molecular patterns in STM images

    Science.gov (United States)

    Maksov, Artem; Ziatdinov, Maxim; Fujii, Shintaro; Kiguchi, Manabu; Higashibayashi, Shuhei; Sakurai, Hidehiro; Kalinin, Sergei; Sumpter, Bobby

    The ability to utilize individual molecules and molecular assemblies as data storage elements has motivated scientist for years, concurrent with the continuous effort to shrink a size of data storage devices in microelectronics industry. One of the critical issues in this effort lies in being able to identify individual molecular assembly units (patterns), on a large scale in an automated fashion of complete information extraction. Here we present a novel method of applying machine learning techniques for extraction of positional and rotational information from scanning tunneling microscopy (STM) images of π-bowl sumanene molecules on gold. We use Markov Random Field (MRF) model to decode the polar rotational states for each molecule in a large scale STM image of molecular film. We further develop an algorithm that uses a convolutional Neural Network combined with MRF and input from density functional theory to classify molecules into different azimuthal rotational classes. Our results demonstrate that a molecular film is partitioned into distinctive azimuthal rotational domains consisting typically of 20-30 molecules. In each domain, the ``bowl-down'' molecules are generally surrounded by six nearest neighbor molecules in ``bowl-up'' configuration, and the resultant overall structure form a periodic lattice of rotational and polar states within each domain. Research was supported by the US Department of Energy.

  8. Structural analysis and unique molecular recognition properties of a Bauhinia forficata lectin that inhibits cancer cell growth.

    Science.gov (United States)

    Lubkowski, Jacek; Durbin, Sarah V; Silva, Mariana C C; Farnsworth, David; Gildersleeve, Jeffrey C; Oliva, Maria Luiza V; Wlodawer, Alexander

    2017-02-01

    Lectins have been used at length for basic research and clinical applications. New insights into the molecular recognition properties enhance our basic understanding of carbohydrate-protein interactions and aid in the design/development of new lectins. In this study, we used a combination of cell-based assays, glycan microarrays, and X-ray crystallography to evaluate the structure and function of the recombinant Bauhinia forficata lectin (BfL). The lectin was shown to be cytostatic for several cancer cell lines included in the NCI-60 panel; in particular, it inhibited growth of melanoma cancer cells (LOX IMVI) by over 95%. BfL is dimeric in solution and highly specific for binding of oligosaccharides and glycopeptides with terminal N-acetylgalactosamine (GalNAc). BfL was found to have especially strong binding (apparent K d  = 0.5-1.0 nm) to the tumor-associated Tn antigen. High-resolution crystal structures were determined for the ligand-free lectin, as well as for its complexes with three Tn glycopeptides, globotetraose, and the blood group A antigen. Extensive analysis of the eight crystal structures and comparison to structures of related lectins revealed several unique features of GalNAc recognition. Of special note, the carboxylate group of Glu126, lining the glycan-binding pocket, forms H-bonds with both the N-acetyl of GalNAc and the peptide amido group of Tn antigens. Stabilization provided by Glu126 is described here for the first time for any GalNAc-specific lectin. Taken together, the results provide new insights into the molecular recognition of carbohydrates and provide a structural understanding that will enable rational engineering of BfL for a variety of applications. Structural data are available in the PDB under the accession numbers 5T50, 5T52, 5T55, 5T54, 5T5L, 5T5J, 5T5P, and 5T5O. © 2016 Federation of European Biochemical Societies.

  9. Dielectric and ferroelectric sensing based on molecular recognition in Cu(1,10-phenlothroline)2SeO4.(diol) systems

    Science.gov (United States)

    Ye, Heng-Yun; Liao, Wei-Qiang; Zhou, Qionghua; Zhang, Yi; Wang, Jinlan; You, Yu-Meng; Wang, Jin-Yun; Chen, Zhong-Ning; Li, Peng-Fei; Fu, Da-Wei; Huang, Songping D.; Xiong, Ren-Gen

    2017-02-01

    The process of molecular recognition is the assembly of two or more molecules through weak interactions. Information in the process of molecular recognition can be transmitted to us via physical signals, which may find applications in sensing and switching. The conventional signals are mainly limited to light signal. Here, we describe the recognition of diols with Cu(1,10-phenlothroline)2SeO4 and the transduction of discrete recognition events into dielectric and/or ferroelectric signals. We observe that systems of Cu(1,10-phenlothroline)2SeO4.(diol) exhibit significant dielectric and/or ferroelectric dependence on different diol molecules. The compounds including ethane-1,2-diol or propane-1,2-diol just show small temperature-dependent dielectric anomalies and no reversible polarization, while the compound including ethane-1,3-diol shows giant temperature-dependent dielectric anomalies as well as ferroelectric reversible spontaneous polarization. This finding shows that dielectricity and/or ferroelectricity has the potential to be used for signalling molecular recognition.

  10. Synthesis and Characterization of Magnetic-Graphene Molecularly Imprinted Polymers for Selective Recognition of Ltryptophan

    Directory of Open Access Journals (Sweden)

    Zhang Yi

    2017-01-01

    Full Text Available In this paper, a novel molecular imprinted polymer using L-tryptophan(L-Trp as the template, dopamine(DA as both functional monomer and cross linking agent, magnetic graphene as the supporting matrix was synthesized. The prepared magnetic-graphene molecularly imprinted polymers(Fe3O4@GO-MIPs were characterized by Fourier transform infrared spectrometer(FT-IR, transmission electron microscopy (TEM, vibrating sample magnetometer (VSM, respectively. The results showed that when the molar ratio of L- tryptophan and dopamine was 1:4 and the reaction temperature was 60 °C, Fe3O4@GO-MIPs had the best adsorption quantity of 31.9 mg/g. The rebinding experiments indicated that Fe3O4@GO-MIPs not only have outstanding affinity and selectivity towards L-Trp over structurally related compounds but also easily reach the magnetic separation under an external magnetic field.

  11. Synthesis and Theoretical Study of Molecularly Imprinted Nanospheres for Recognition of Tocopherols

    Directory of Open Access Journals (Sweden)

    Chartchalerm Isarankura-Na-Ayudhya

    2009-08-01

    Full Text Available Molecular imprinting is a technology that facilitates the production of artificial receptors toward compounds of interest. The molecularly imprinted polymers act as artificial antibodies, artificial receptors, or artificial enzymes with the added benefit over their biological counterparts of being highly durable. In this study, we prepared molecularly imprinted polymers for the purpose of binding specifically to tocopherol (vitamin E and its derivative, tocopherol acetate. Binding of the imprinted polymers to the template was found to be two times greater than that of the control, non-imprinted polymers, when using only 10 mg of polymers. Optimization of the rebinding solvent indicated that ethanol-water at a molar ratio of 6:4 (v/v was the best solvent system as it enhanced the rebinding performance of the imprinted polymers toward both tocopherol and tocopherol acetate with a binding capacity of approximately 2 mg/g of polymer. Furthermore, imprinted nanospheres against tocopherol was successfully prepared by precipitation polymerization with ethanol-water at a molar ratio of 8:2 (v/v as the optimal rebinding solvent. Computer simulation was also performed to provide mechanistic insights on the binding mode of template-monomer complexes. Such polymers show high potential for industrial and medical applications, particularly for selective separation of tocopherol and derivatives.

  12. Molecular mechanism of ligand recognition by membrane transport protein, Mhp1

    Science.gov (United States)

    Simmons, Katie J; Jackson, Scott M; Brueckner, Florian; Patching, Simon G; Beckstein, Oliver; Ivanova, Ekaterina; Geng, Tian; Weyand, Simone; Drew, David; Lanigan, Joseph; Sharples, David J; Sansom, Mark SP; Iwata, So; Fishwick, Colin WG; Johnson, A Peter; Cameron, Alexander D; Henderson, Peter JF

    2014-01-01

    The hydantoin transporter Mhp1 is a sodium-coupled secondary active transport protein of the nucleobase-cation-symport family and a member of the widespread 5-helix inverted repeat superfamily of transporters. The structure of Mhp1 was previously solved in three different conformations providing insight into the molecular basis of the alternating access mechanism. Here, we elucidate detailed events of substrate binding, through a combination of crystallography, molecular dynamics, site-directed mutagenesis, biochemical/biophysical assays, and the design and synthesis of novel ligands. We show precisely where 5-substituted hydantoin substrates bind in an extended configuration at the interface of the bundle and hash domains. They are recognised through hydrogen bonds to the hydantoin moiety and the complementarity of the 5-substituent for a hydrophobic pocket in the protein. Furthermore, we describe a novel structure of an intermediate state of the protein with the external thin gate locked open by an inhibitor, 5-(2-naphthylmethyl)-L-hydantoin, which becomes a substrate when leucine 363 is changed to an alanine. We deduce the molecular events that underlie acquisition and transport of a ligand by Mhp1. PMID:24952894

  13. Preparation of a molecularly imprinted sensor based on quartz crystal microbalance for specific recognition of sialic acid in human urine.

    Science.gov (United States)

    Qiu, Xiuzhen; Xu, Xian-Yan; Chen, Xuncai; Wu, Yiyong; Guo, Huishi

    2018-05-08

    A novel molecularly imprinted quartz crystal microbalance (QCM) sensor was successfully prepared for selective determination of sialic acid (SA) in human urine samples. To obtain the QCM sensor, we first modified the gold surface of the QCM chip by self-assembling of allylmercaptane to introduce polymerizable double bonds on the chip surface. Then, SA molecularly imprinted polymer (MIP) nanofilm was attached to the modified QCM chip surface. For comparison, we have also characterized the nonmodified and improved surfaces of the QCM sensor by using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. We then tested the selectivity and detection limit of the imprinted QCM sensor via a series of adsorption experiments. The results show a linear response in the range of 0.025-0.50 μmol L -1 for sialic acid. Moreover, the limit of detection (LOD) of the prepared imprinted QCM sensor was found to be 1.0 nmol L -1 for sialic acid, and high recovery values range from 87.6 to 108.5% with RSD sensor was developed and used to detect sialic acid in human urine samples. Graphical abstract Specific recognition of sialic acid by the MIP-QCM sensor system.

  14. Molecular recognition of the environment and mechanisms of the origin of species in quantum-like modeling of evolution.

    Science.gov (United States)

    Melkikh, Alexey V; Khrennikov, Andrei

    2017-11-01

    A review of the mechanisms of speciation is performed. The mechanisms of the evolution of species, taking into account the feedback of the state of the environment and mechanisms of the emergence of complexity, are considered. It is shown that these mechanisms, at the molecular level, cannot work steadily in terms of classical mechanics. Quantum mechanisms of changes in the genome, based on the long-range interaction potential between biologically important molecules, are proposed as one of possible explanation. Different variants of interactions of the organism and environment based on molecular recognition and leading to new species origins are considered. Experiments to verify the model are proposed. This bio-physical study is completed by the general operational model of based on quantum information theory. The latter is applied to model of epigenetic evolution. We briefly present the basics of the quantum-like approach to modeling of bio-informational processes. This approach is illustrated by the quantum-like model of epigenetic evolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Characterization of the molecular basis of group II intron RNA recognition by CRS1-CRM domains.

    Science.gov (United States)

    Keren, Ido; Klipcan, Liron; Bezawork-Geleta, Ayenachew; Kolton, Max; Shaya, Felix; Ostersetzer-Biran, Oren

    2008-08-22

    CRM (chloroplast RNA splicing and ribosome maturation) is a recently recognized RNA-binding domain of ancient origin that has been retained in eukaryotic genomes only within the plant lineage. Whereas in bacteria CRM domains exist as single domain proteins involved in ribosome maturation, in plants they are found in a family of proteins that contain between one and four repeats. Several members of this family with multiple CRM domains have been shown to be required for the splicing of specific plastidic group II introns. Detailed biochemical analysis of one of these factors in maize, CRS1, demonstrated its high affinity and specific binding to the single group II intron whose splicing it facilitates, the plastid-encoded atpF intron RNA. Through its association with two intronic regions, CRS1 guides the folding of atpF intron RNA into its predicted "catalytically active" form. To understand how multiple CRM domains cooperate to achieve high affinity sequence-specific binding to RNA, we analyzed the RNA binding affinity and specificity associated with each individual CRM domain in CRS1; whereas CRM3 bound tightly to the RNA, CRM1 associated specifically with a unique region found within atpF intron domain I. CRM2, which demonstrated only low binding affinity, also seems to form specific interactions with regions localized to domains I, III, and IV. We further show that CRM domains share structural similarities and RNA binding characteristics with the well known RNA recognition motif domain.

  16. Dissecting molecular interactions involved in recognition of target disulfides by the barley thioredoxin system

    DEFF Research Database (Denmark)

    Björnberg, Olof; Maeda, Kenji; Svensson, Birte

    2012-01-01

    Thioredoxin reduces disulfide bonds, thus regulating activities of target proteins in various biological systems, e.g., inactivation of inhibitors of starch hydrolases and proteases in germinating plant seeds. In the three-dimensional structure of a complex with barley α-amylase/subtilisin inhibi......Thioredoxin reduces disulfide bonds, thus regulating activities of target proteins in various biological systems, e.g., inactivation of inhibitors of starch hydrolases and proteases in germinating plant seeds. In the three-dimensional structure of a complex with barley α...... thioredoxin reductase. HvTrxh2 M88G and M88A adjacent to the invariant cis-proline lost efficiency in both BASI disulfide reduction and recycling by thioredoxin reductase. These effects were further pronounced in M88P lacking a backbone NH group. Remarkably, HvTrxh2 E86R in the same loop displayed overall...... retained catalytic properties, with the exception of a 3-fold increased activity toward BASI. From the 104VGA106 loop, a backbone hydrogen bond donated by A106 appears to be important for target disulfide recognition as A106P lost 90% activity toward BASI but was efficiently recycled by thioredoxin...

  17. Comparison of extraction chromatography and a procedure based on the molecular recognition method as separation methods in the determination of neptunium and plutonium radionuclides

    International Nuclear Information System (INIS)

    Strisovska, Jana; Galanda, Dusan; Drabova, Veronika; Kuruc, Jozef

    2012-01-01

    The potential of various types of sorbents for separation of radionuclides of plutonium and neptunium were examined. Extraction chromatography and a procedure based on the molecular recognition method were used for the separation. The suitability of the various sorbent types and brands for this purpose was determined. (orig.)

  18. iBodies: modular synthetic antibody mimetics based on hydrophilic polymers decorated with functional moieties as tools for molecular recognition, imaging and specific drug delivery

    Czech Academy of Sciences Publication Activity Database

    Šácha, Pavel; Dvořáková, Petra; Knedlík, Tomáš; Schimer, Jiří; Šubr, Vladimír; Ulbrich, Karel; Bušek, P.; Navrátil, Václav; Sedlák, František; Majer, Pavel; Šedo, A.; Konvalinka, Jan

    2017-01-01

    Roč. 284, Suppl 1 (2017), s. 340 ISSN 1742-464X. [FEBS Congress /42./ From Molecules to Cells and Back. 10.09.2017-14.09.2017, Jerusalem] Institutional support: RVO:61388963 ; RVO:61389013 Keywords : antibody mimetics * molecular recognition * polymer conjugates Subject RIV: CE - Biochemistry

  19. Conductometric Sensor for PAH Detection with Molecularly Imprinted Polymer as Recognition Layer

    Directory of Open Access Journals (Sweden)

    Usman Latif

    2018-03-01

    Full Text Available A conductometric sensor based on screen-printed interdigital gold electrodes on glass substrate coated with molecularly imprinted polyurethane layers was fabricated to detect polycyclic aromatic hydrocarbons (PAHs in water. The results prove that screen-printed interdigital electrodes are very suitable transducers to fabricate low-cost sensor systems for measuring change in resistance of PAH-imprinted layers while exposing to different PAHs. The sensor showed good selectivity to its templated molecules and high sensitivity with a detection limit of 1.3 nmol/L e.g., for anthracene in water which is lower than WHO’s permissible limit.

  20. Application of TensorFlow to recognition of visualized results of fragment molecular orbital (FMO) calculations

    OpenAIRE

    Saitou, Sona; Iijima, Jun; Fujimoto, Mayu; Mochizuki, Yuji; Okuwaki, Koji; Doi, Hideo; Komeiji, Yuto

    2018-01-01

    We have applied Google's TensorFlow deep learning toolkit to recognize the visualized results of the fragment molecular orbital (FMO) calculations. Typical protein structures of alpha-helix and beta-sheet provide some characteristic patterns in the two-dimensional map of inter-fragment interaction energy termed as IFIE-map (Kurisaki et al., Biophys. Chem. 130 (2007) 1). A thousand of IFIE-map images with labels depending on the existences of alpha-helix and beta-sheet were prepared by employi...

  1. Molecular recognition of live methicillin-resistant staphylococcus aureus cells using DNA aptamers.

    Science.gov (United States)

    Turek, Diane; Van Simaeys, Dimitri; Johnson, Judith; Ocsoy, Ismail; Tan, Weihong

    2013-01-01

    To generate DNA-aptamers binding to Methicillin-resistant Staphylococcus aureus (MRSA) . The Cell-Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology was used to run the selection against MRSA bacteria and develop target-specific aptamers. MRSA bacteria were targeted while Enterococcus faecalis bacteria were used for counter selection during that process. Binding assays to determine the right aptamer candidates as well as binding assays on clinical samples were performed through flow cytometry and analyzed using the FlowJo software. The characterization of the aptamers was done by determination of their K d values and determined by analysis of flow data at different aptamer concentration using SigmaPlot. Finally, the recognition of the complex Gold-nanoparticle-aptamer to the bacteria cells was observed using transmission electron microscopy (TEM). During the cell-SELEX selection process, 17 rounds were necessary to generate enrichment of the pool. While the selection was run using fixed cells, it was shown that the binding of the pools with live cells was giving similar results. After sequencing and analysis of the two last pools, four sequences were identified to be aptamer candidates. The characterization of those aptamers showed that based on their K d values, DTMRSA4 presented the best binding with a K d value of 94.61 ± 18.82 nmol/L. A total of ten clinical samples of MRSA , S. aureus and Enterococcus faecalis were obtained to test those aptamers and determine their binding on a panel of samples. DTMRSA1 and DTMRSA3 showed the best results regarding their specificity to MRSA , DTMRSA1 being the most specific of all. Finally, those aptamers were coupled with gold-nanoparticle and their binding to MRSA cells was visualized through TEM showing that adduction of nanoparticles on the aptamers did not change their binding property. A total of four aptamers that bind to MRSA were obtained with K d values ranking from 94 to 200 nmol/L.

  2. Molecular recognition of ketamine by a subset of olfactory G protein–coupled receptors

    Science.gov (United States)

    Saven, Jeffery G.; Matsunami, Hiroaki; Eckenhoff, Roderic G.

    2015-01-01

    Ketamine elicits various neuropharmacological effects, including sedation, analgesia, general anesthesia, and antidepressant activity. Through an in vitro screen, we identified four mouse olfactory receptors (ORs) that responded to ketamine. In addition to their presence in the olfactory epithelium, these G protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptors (GPCRs) are distributed throughout the central nervous system. To better understand the molecular basis of the interactions between ketamine and ORs, we used sequence comparison and molecular modeling to design mutations that (i) increased, reduced, or abolished ketamine responsiveness in responding receptors, and (ii) rendered non-responding receptors responsive to ketamine. We showed that olfactory sensory neurons (OSNs) that expressed distinct ORs responded to ketamine in vivo, suggesting that ORs may serve as functional targets for ketamine. The ability to both abolish and introduce responsiveness to ketamine in GPCRs enabled us to identify and confirm distinct interaction loci in the binding site, which suggested a signature ketamine-binding pocket that may guide exploration of additional receptors for this general anesthetic drug. PMID:25829447

  3. Sequence analysis of serum albumins reveals the molecular evolution of ligand recognition properties.

    Science.gov (United States)

    Fanali, Gabriella; Ascenzi, Paolo; Bernardi, Giorgio; Fasano, Mauro

    2012-01-01

    Serum albumin (SA) is a circulating protein providing a depot and carrier for many endogenous and exogenous compounds. At least seven major binding sites have been identified by structural and functional investigations mainly in human SA. SA is conserved in vertebrates, with at least 49 entries in protein sequence databases. The multiple sequence analysis of this set of entries leads to the definition of a cladistic tree for the molecular evolution of SA orthologs in vertebrates, thus showing the clustering of the considered species, with lamprey SAs (Lethenteron japonicum and Petromyzon marinus) in a separate outgroup. Sequence analysis aimed at searching conserved domains revealed that most SA sequences are made up by three repeated domains (about 600 residues), as extensively characterized for human SA. On the contrary, lamprey SAs are giant proteins (about 1400 residues) comprising seven repeated domains. The phylogenetic analysis of the SA family reveals a stringent correlation with the taxonomic classification of the species available in sequence databases. A focused inspection of the sequences of ligand binding sites in SA revealed that in all sites most residues involved in ligand binding are conserved, although the versatility towards different ligands could be peculiar of higher organisms. Moreover, the analysis of molecular links between the different sites suggests that allosteric modulation mechanisms could be restricted to higher vertebrates.

  4. Nanosilica-based molecularly imprinted polymer nanoshell for specific recognition and determination of rhodamine B in red wine and beverages.

    Science.gov (United States)

    Long, Zerong; Xu, Weiwei; Lu, Yi; Qiu, Hongdeng

    2016-09-01

    A new and facile rhodamine B (RhB)-imprinted polymer nanoshell coating for SiO2 nanoparticles was readily prepared by a combination of silica gel modification and molecular surface imprinting. The RhB-imprinted polymers (RhB-MIPs) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and UV-vis spectroscopy; the binding properties and selectivity of these MIPs were investigated in detail. The uniformly imprinted nanoparticles displayed a rather thin shell thickness (23nm) with highly effective recognition sites, showing homogenous distribution and monolayer adsorption. The maximum MIP adsorption capacity (Qm) was as high as 45.2mgg(-1), with an adsorption equilibrium time of about 15min at ambient temperature. Dynamic rebinding experiments showed that chemical adsorption is crucial for RhB binding to RhB-MIPs. The adsorption isotherm for RhB-MIPs binding could also be described by the Langmuir equation at different temperatures and pH values. Increasing temperature led to an enhanced Qm, a decreased dissociation constant (K'd), and a more negative free energy (ΔG), indicating that adsorption is favored at higher temperatures. Moreover, the adsorption capacity of RhB was remarkably affected by pH. At pH>7, the adsorption of RhB was driven by hydrogen bonding interactions, while at pH<7 electrostatic forces were dominant. Additionally, the MIPs also showed specific recognition of RhB from the standard mixture solution containing five structurally analogs. This method was also successfully employed to determine RhB content in red wine and beverages using three levels of spiking, with recoveries in the range of 91.6-93.1% and relative standard deviations lower than 4.1%. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. A structural and mutagenic blueprint for molecular recognition of strychnine and d-tubocurarine by different cys-loop receptors.

    Directory of Open Access Journals (Sweden)

    Marijke Brams

    2011-03-01

    Full Text Available Cys-loop receptors (CLR are pentameric ligand-gated ion channels that mediate fast excitatory or inhibitory transmission in the nervous system. Strychnine and d-tubocurarine (d-TC are neurotoxins that have been highly instrumental in decades of research on glycine receptors (GlyR and nicotinic acetylcholine receptors (nAChR, respectively. In this study we addressed the question how the molecular recognition of strychnine and d-TC occurs with high affinity and yet low specificity towards diverse CLR family members. X-ray crystal structures of the complexes with AChBP, a well-described structural homolog of the extracellular domain of the nAChRs, revealed that strychnine and d-TC adopt multiple occupancies and different ligand orientations, stabilizing the homopentameric protein in an asymmetric state. This introduces a new level of structural diversity in CLRs. Unlike protein and peptide neurotoxins, strychnine and d-TC form a limited number of contacts in the binding pocket of AChBP, offering an explanation for their low selectivity. Based on the ligand interactions observed in strychnine- and d-TC-AChBP complexes we performed alanine-scanning mutagenesis in the binding pocket of the human α1 GlyR and α7 nAChR and showed the functional relevance of these residues in conferring high potency of strychnine and d-TC, respectively. Our results demonstrate that a limited number of ligand interactions in the binding pocket together with an energetic stabilization of the extracellular domain are key to the poor selective recognition of strychnine and d-TC by CLRs as diverse as the GlyR, nAChR, and 5-HT(3R.

  6. Fuzzy method of recognition of high molecular substances in evidence-based biology

    Science.gov (United States)

    Olevskyi, V. I.; Smetanin, V. T.; Olevska, Yu. B.

    2017-10-01

    Nowadays modern requirements to achieving reliable results along with high quality of researches put mathematical analysis methods of results at the forefront. Because of this, evidence-based methods of processing experimental data have become increasingly popular in the biological sciences and medicine. Their basis is meta-analysis, a method of quantitative generalization of a large number of randomized trails contributing to a same special problem, which are often contradictory and performed by different authors. It allows identifying the most important trends and quantitative indicators of the data, verification of advanced hypotheses and discovering new effects in the population genotype. The existing methods of recognizing high molecular substances by gel electrophoresis of proteins under denaturing conditions are based on approximate methods for comparing the contrast of electrophoregrams with a standard solution of known substances. We propose a fuzzy method for modeling experimental data to increase the accuracy and validity of the findings of the detection of new proteins.

  7. Transfer of molecular recognition information from DNA nanostructures to gold nanoparticles

    Science.gov (United States)

    Edwardson, Thomas G. W.; Lau, Kai Lin; Bousmail, Danny; Serpell, Christopher J.; Sleiman, Hanadi F.

    2016-02-01

    DNA nanotechnology offers unparalleled precision and programmability for the bottom-up organization of materials. This approach relies on pre-assembling a DNA scaffold, typically containing hundreds of different strands, and using it to position functional components. A particularly attractive strategy is to employ DNA nanostructures not as permanent scaffolds, but as transient, reusable templates to transfer essential information to other materials. To our knowledge, this approach, akin to top-down lithography, has not been examined. Here we report a molecular printing strategy that chemically transfers a discrete pattern of DNA strands from a three-dimensional DNA structure to a gold nanoparticle. We show that the particles inherit the DNA sequence configuration encoded in the parent template with high fidelity. This provides control over the number of DNA strands and their relative placement, directionality and sequence asymmetry. Importantly, the nanoparticles produced exhibit the site-specific addressability of DNA nanostructures, and are promising components for energy, information and biomedical applications.

  8. Molecular recognition applied to gas detection: the contribution of Langmuir-Blodgett films

    International Nuclear Information System (INIS)

    Clemendot, Sylvain

    1992-01-01

    In the first part of this research thesis, the author presents the Langmuir-Blodgett technique and outlines how it can face the challenge of molecular electronics. Then, he proposes an overview of the state-of-the-art of chemical sensors based on LB films, and an assessment of the state of the art of conductive LB films based on TCNQ (tetracyanoquinodimethane) and on tetrathiafulvalene for which the author proposes a modelling. He describes how phosphine sensors with varying conductivity based on TCNQ-based conductive LB films have been developed and reports the study of electric performance of these sensors. He describes and compares mechanisms of interaction of phosphine with conductive LB films for films based on TCNQ and those based on tetrathiafulvalene [fr

  9. A Targeted "Capture" and "Removal" Scavenger toward Multiple Pollutants for Water Remediation based on Molecular Recognition.

    Science.gov (United States)

    Wang, Jie; Shen, Haijing; Hu, Xiaoxia; Li, Yan; Li, Zhihao; Xu, Jinfan; Song, Xiufeng; Zeng, Haibo; Yuan, Quan

    2016-03-01

    For the water remediation techniques based on adsorption, the long-standing contradictories between selectivity and multiple adsorbability, as well as between affinity and recyclability, have put it on weak defense amid more and more severe environment crisis. Here, a pollutant-targeting hydrogel scavenger is reported for water remediation with both high selectivity and multiple adsorbability for several pollutants, and with strong affinity and good recyclability through rationally integrating the advantages of multiple functional materials. In the scavenger, aptamers fold into binding pockets to accommodate the molecular structure of pollutants to afford perfect selectivity, and Janus nanoparticles with antibacterial function as well as anisotropic surfaces to immobilize multiple aptamers allow for simultaneously handling different kinds of pollutants. The scavenger exhibits high efficiencies in removing pollutants from water and it can be easily recycled for many times without significant loss of loading capacities. Moreover, the residual concentrations of each contaminant are well below the drinking water standards. Thermodynamic behavior of the adsorption process is investigated and the rate-controlling process is determined. Furthermore, a point of use device is constructed and it displays high efficiency in removing pollutants from environmental water. The scavenger exhibits great promise to be applied in the next generation of water purification systems.

  10. Molecular imprinting polymer with polyoxometalate/carbon nitride nanotubes for electrochemical recognition of bilirubin

    International Nuclear Information System (INIS)

    Yola, Mehmet Lütfi; Göde, Ceren; Atar, Necip

    2017-01-01

    Highlights: •Bilirubin-imprinted sensor is developed for the sensitive detection of bilirubin •The prepared based on nanocomposite were characterized by several methods. •Bilirubin-imprinted sensor offers the important advantages •Bilirubin-imprinted sensor is preferred to the other methods for analysis -- Abstract: In this work, a new molecular imprinted sensor based on polyoxometalate (H 3 PW 12 O 40 , POM) functionalized carbon nitride nanotubes (C 3 N 4 NTs) nanocomposite was prepared for bilirubin (BR) analysis. The structures of prepared surfaces based on the nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray analysis (EDX). After that, BR imprinted electrode on H 3 PW 12 O 40 /C 3 N 4 NTs nanocomposite was developed by cyclic voltammetry (CV) in 100 mM pyrrole containing 25 mM BR. The linearity range and the detection limit of the developed method were calculated as 1.0 × 10 −12 –1.0 × 10 −10 M and 3.0 × 10 −13 M, respectively. In addition, the imprinted sensor was applied to human plasma samples with high recovery and selectivity.

  11. Recognition of dual targets by a molecular beacon-based sensor: subtyping of influenza A virus.

    Science.gov (United States)

    Lee, Chun-Ching; Liao, Yu-Chieh; Lai, Yu-Hsuan; Lee, Chang-Chun David; Chuang, Min-Chieh

    2015-01-01

    A molecular beacon (MB)-based sensor to offer a decisive answer in combination with information originated from dual-target inputs is designed. The system harnesses an assistant strand and thermodynamically favored designation of unpaired nucleotides (UNs) to process the binary targets in "AND-gate" format and report fluorescence in "off-on" mechanism via a formation of a DNA four-way junction (4WJ). By manipulating composition of the UNs, the dynamic fluorescence difference between the binary targets-coexisting circumstance and any other scenario was maximized. Characteristic equilibrium constant (K), change of entropy (ΔS), and association rate constant (k) between the association ("on") and dissociation ("off") states of the 4WJ were evaluated to understand unfolding behavior of MB in connection to its sensing capability. Favorable MB and UNs were furthermore designed toward analysis of genuine genetic sequences of hemagglutinin (HA) and neuraminidase (NA) in an influenza A H5N2 isolate. The MB-based sensor was demonstrated to yield a linear calibration range from 1.2 to 240 nM and detection limit of 120 pM. Furthermore, high-fidelity subtyping of influenza virus was implemented in a sample of unpurified amplicons. The strategy opens an alternative avenue of MB-based sensors for dual targets toward applications in clinical diagnosis.

  12. Preparation and evaluation of molecularly imprinted polymer for selective recognition and adsorption of gossypol.

    Science.gov (United States)

    Zhi, Keke; Wang, Lulu; Zhang, Yagang; Zhang, Xuemin; Zhang, Letao; Liu, Li; Yao, Jun; Xiang, Wei

    2018-03-01

    Molecularly imprinted polymers (MIPs) were designed and prepared via bulk thermal polymerization with gossypol as the template molecule and dimethylaminoethyl methacrylate as the functional monomer. The morphology and microstructures of MIPs were characterized by scanning electron microscope and Brunauer-Emmett-Teller surface areas. Static adsorption tests were performed to evaluate adsorption behavior of gossypol by the MIPs. It was found that adsorption kinetics and adsorption isotherms data of MIPs for gossypol were fit well with the pseudo-second-order model and Freundlich model, respectively. Scatchard analysis showed that heterogeneous binding sites were formed in the MIPs, including lower-affinity binding sites with the maximum adsorption of 252 mg/g and higher-affinity binding sites with the maximum adsorption of 632 mg/g. Binding studies also revealed that MIPs had favorable selectivity towards gossypol compared with non-imprinted polymers. Furthermore, adsorption capacity of MIPs maintained above 90% after 5 regeneration cycles, indicating MIPs were recyclable and could be used multiple times. These results demonstrated that prepared MIPs could be a promising functional material for selective adsorption of gossypol. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Abstracts of the 27. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    1998-01-01

    This meeting was about biochemistry and molecular biology. It was discussed topics related to bio energetic, channels, transports, biotechnology, metabolism, cellular biology, immunology, toxicology, photobiology and pharmacology

  14. Abstracts of the 26. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    1997-01-01

    This meeting was about biochemistry and molecular biology. It was discussed topics related to bio energetic, channels, transports, biotechnology, metabolism, cellular biology, immunology, toxicology, photobiology and pharmacology

  15. Electrochemical sensor for catechol and dopamine based on a catalytic molecularly imprinted polymer-conducting polymer hybrid recognition element.

    Science.gov (United States)

    Lakshmi, Dhana; Bossi, Alessandra; Whitcombe, Michael J; Chianella, Iva; Fowler, Steven A; Subrahmanyam, Sreenath; Piletska, Elena V; Piletsky, Sergey A

    2009-05-01

    One of the difficulties with using molecularly imprinted polymers (MIPs) and other electrically insulating materials as the recognition element in electrochemical sensors is the lack of a direct path for the conduction of electrons from the active sites to the electrode. We have sought to address this problem through the preparation and characterization of novel hybrid materials combining a catalytic MIP, capable of oxidizing the template, catechol, with an electrically conducting polymer. In this way a network of "molecular wires" assists in the conduction of electrons from the active sites within the MIP to the electrode surface. This was made possible by the design of a new monomer that combines orthogonal polymerizable functionality; comprising an aniline group and a methacrylamide. Conducting films were prepared on the surface of electrodes (Au on glass) by electropolymerization of the aniline moiety. A layer of MIP was photochemically grafted over the polyaniline, via N,N'-diethyldithiocarbamic acid benzyl ester (iniferter) activation of the methacrylamide groups. Detection of catechol by the hybrid-MIP sensor was found to be specific, and catechol oxidation was detected by cyclic voltammetry at the optimized operating conditions: potential range -0.6 V to +0.8 V (vs Ag/AgCl), scan rate 50 mV/s, PBS pH 7.4. The calibration curve for catechol was found to be linear to 144 microM, with a limit of detection of 228 nM. Catechol and dopamine were detected by the sensor, whereas analogues and potentially interfering compounds, including phenol, resorcinol, hydroquinone, serotonin, and ascorbic acid, had minimal effect (< or = 3%) on the detection of either analyte. Non-imprinted hybrid electrodes and bare gold electrodes failed to give any response to catechol at concentrations below 0.5 mM. Finally, the catalytic properties of the sensor were characterized by chronoamperometry and were found to be consistent with Michaelis-Menten kinetics.

  16. Molecular recognition of floral volatile with two olfactory related proteins in the Eastern honeybee (Apis cerana).

    Science.gov (United States)

    Li, Hongliang; Zhang, Linya; Ni, Cuixia; Shang, Hanwu; Zhuang, Shulin; Li, Jianke

    2013-05-01

    The honeybee relies on its sensitive olfaction to perform the foraging activities in the field. In the antennal chemoreception system of honeybee, odorant-binding proteins (OBPs) and chemosensory protein (CSPs) are major two protein families capable of binding with some plant volatiles and chemical ligands. However, the chemical binding interaction of plant odors with OBPs and CSPs in the honeybee olfactory system is still not clear yet. Hence, complex fluorescent spectra, ultraviolet absorption spectra, circular dichroism spectra and molecular docking were used to investigate the binding property of AcerASP2 (an OBP of Apis cerana) and AcerASP3 (a CSP of Apis cerana) with β-ionone, one of ordinary floral volatiles in botanical flower. As a result, β-ionone had a strong capability to quench the fluorescence that the two proteins produced, and their interaction was a dynamic process that was mainly driven by a hydrophobic force. AcerASP2 had a larger hydrophobic cavity than that of AcerASP3 and the conformation of AcerASP2 was changed less than AcerASP3 when binding with β-ionone. Our data suggests that OBPs like AcerASP2 might make a large contribution toward assisting the honeybee in sensing and foraging flowers, and A. cerana has evolved a good circadian rhythm to perceive a flower's odor following the fluctuation of temperature in the olfactory system. This significantly extends our knowledge on how to strengthen the honeybees' pollination service via manipulation of target proteins in the olfactory system. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. The molecular bases of δ/αβ T cell-mediated antigen recognition.

    Science.gov (United States)

    Pellicci, Daniel G; Uldrich, Adam P; Le Nours, Jérôme; Ross, Fiona; Chabrol, Eric; Eckle, Sidonia B G; de Boer, Renate; Lim, Ricky T; McPherson, Kirsty; Besra, Gurdyal; Howell, Amy R; Moretta, Lorenzo; McCluskey, James; Heemskerk, Mirjam H M; Gras, Stephanie; Rossjohn, Jamie; Godfrey, Dale I

    2014-12-15

    αβ and γδ T cells are disparate T cell lineages that can respond to distinct antigens (Ags) via the use of the αβ and γδ T cell Ag receptors (TCRs), respectively. Here we characterize a population of human T cells, which we term δ/αβ T cells, expressing TCRs comprised of a TCR-δ variable gene (Vδ1) fused to joining α and constant α domains, paired with an array of TCR-β chains. We demonstrate that these cells, which represent ∼50% of all Vδ1(+) human T cells, can recognize peptide- and lipid-based Ags presented by human leukocyte antigen (HLA) and CD1d, respectively. Similar to type I natural killer T (NKT) cells, CD1d-lipid Ag-reactive δ/αβ T cells recognized α-galactosylceramide (α-GalCer); however, their fine specificity for other lipid Ags presented by CD1d, such as α-glucosylceramide, was distinct from type I NKT cells. Thus, δ/αβTCRs contribute new patterns of Ag specificity to the human immune system. Furthermore, we provide the molecular bases of how δ/αβTCRs bind to their targets, with the Vδ1-encoded region providing a major contribution to δ/αβTCR binding. Our findings highlight how components from αβ and γδTCR gene loci can recombine to confer Ag specificity, thus expanding our understanding of T cell biology and TCR diversity. © 2014 Pellicci et al.

  18. The molecular bases of δ/αβ T cell–mediated antigen recognition

    Science.gov (United States)

    Pellicci, Daniel G.; Uldrich, Adam P.; Le Nours, Jérôme; Ross, Fiona; Chabrol, Eric; Eckle, Sidonia B.G.; de Boer, Renate; Lim, Ricky T.; McPherson, Kirsty; Besra, Gurdyal; Howell, Amy R.; Moretta, Lorenzo; McCluskey, James; Heemskerk, Mirjam H.M.; Gras, Stephanie

    2014-01-01

    αβ and γδ T cells are disparate T cell lineages that can respond to distinct antigens (Ags) via the use of the αβ and γδ T cell Ag receptors (TCRs), respectively. Here we characterize a population of human T cells, which we term δ/αβ T cells, expressing TCRs comprised of a TCR-δ variable gene (Vδ1) fused to joining α and constant α domains, paired with an array of TCR-β chains. We demonstrate that these cells, which represent ∼50% of all Vδ1+ human T cells, can recognize peptide- and lipid-based Ags presented by human leukocyte antigen (HLA) and CD1d, respectively. Similar to type I natural killer T (NKT) cells, CD1d-lipid Ag-reactive δ/αβ T cells recognized α-galactosylceramide (α-GalCer); however, their fine specificity for other lipid Ags presented by CD1d, such as α-glucosylceramide, was distinct from type I NKT cells. Thus, δ/αβTCRs contribute new patterns of Ag specificity to the human immune system. Furthermore, we provide the molecular bases of how δ/αβTCRs bind to their targets, with the Vδ1-encoded region providing a major contribution to δ/αβTCR binding. Our findings highlight how components from αβ and γδTCR gene loci can recombine to confer Ag specificity, thus expanding our understanding of T cell biology and TCR diversity. PMID:25452463

  19. Molecular basis for H3K36me3 recognition by the Tudor domain of PHF1

    Science.gov (United States)

    Musselman, Catherine A.; Avvakumov, Nikita; Watanabe, Reiko; Abraham, Christopher G.; Lalonde, Marie-Eve; Hong, Zehui; Allen, Christopher; Roy, Siddhartha; Nuñez, James K.; Nickoloff, Jac; Kulesza, Caroline A.; Yasui, Akira; Côté, Jacques; Kutateladze, Tatiana G.

    2013-01-01

    The PHD finger protein 1 (PHF1) is essential in epigenetic regulation and genome maintenance. Here, we demonstrate that the Tudor domain of human PHF1 binds to histone H3 trimethylated at Lys36 (H3K36me3). We report a 1.9 Å resolution crystal structure of the Tudor domain in complex with H3K36me3 and describe the molecular mechanism of H3K36me3 recognition using NMR analysis. Binding of PHF1 to H3K36me3 inhibits the ability of the Polycomb PRC2 complex to methylate H3K27 in vitro and in vivo. Laser micro-irradiation data reveal that PHF1 is transiently recruited to DNA double-strand breaks (DSBs), and PHF1 mutants impaired in the H3K36me3 interaction exhibit reduced retention at DSB sites. Together, our findings suggest that PHF1 can mediate deposition of the repressive H3K27me3 mark and acts as an early DNA damage response cofactor. PMID:23142980

  20. Structural, mutational and biophysical studies reveal a canonical mode of molecular recognition between immune receptor TIGIT and nectin-2

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, Dibyendu; Guo, Haisu; Rubinstein, Rotem; Ramagopal, Udupi A.; Almo, Steven C.

    2017-01-01

    In addition to antigen-specific stimulation of T cell receptor (TCR) by a peptide-MHC complex, the functional outcome of TCR engagement is regulated by antigen-independent costimulatory signals. Costimulatory signals are provided by an array of interactions involving activating and inhibitory receptors expressed on T cells and their cognate ligands on antigen presenting cells. T cell immunoglobulin and ITIM domain (TIGIT), a recently identified immune receptor expressed on T and NK cells, upon interaction with either of its two ligands, nectin-2 or poliovirus receptor (PVR), inhibits activation of T and NK cells. Here we report the crystal structure of the human TIGIT ectodomain, which exhibits the classic two-layer β-sandwich topology observed in other immunoglobulin super family (IgSF) members. Biophysical studies indicate that TIGIT is monomeric in solution but can form a dimer at high concentrations, consistent with the observation of a canonical immunoglobulin-like dimer interface in the crystalline state. Based on existing structural data, we present a model of the TIGIT:nectin-2 complex and utilized complementary biochemical studies to map the nectin-binding interface on TIGIT. Our data provide important structural and biochemical determinants responsible for the recognition of nectin-2 by TIGIT. Defining the TIGIT:nectin-2 binding interface provides the basis for rational manipulation of this molecular interaction for the development of immunotherapeutic reagents in autoimmunity and cancer.

  1. [Preparation of molecularly imprinted polypyrrole/Fe3O4 composite material and its application in recognition of tryptophan enantiomers].

    Science.gov (United States)

    Chen, Zhidong; Shan, Xueling; Kong, Yong

    2012-04-01

    Ferrosoferric oxide (Fe(3)O(4)) magnetic material was first synthesized, and then the in-situ chemical polymerization of pyrrole was carried out on the surface of Fe(3)O(4) by using pyrole and L-tryptophan (L-Trp) as the functional monomer and templates, respectively. As a result, molecularly imprinted polypyrrole/Fe(3)O(4) composite material was obtained. This composite material was separated from the solution because of its magnetic property. Polypyrrole in the composite was overoxidized in 1 mol/L NaOH solution by applying a potential of 1.0 V, and thus L-Trp templates were de-deoped from the composite. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods were employed to characterize the composite. The solution containing L- or D-Trp was pumped through a porous ceramic tube packed with the composite, separately. High performance liquid chromatography (HPLC) was adopted for the detection of L- or D-Trp in the eluate, and the results indicated that the enrichment ability of the composite for L-Trp was almost 2 times that of D-Trp. Therefore, the electro-magnetic composite material has potential applications as chromatographic stationary phase for chiral recognition.

  2. Helicase-Dependent Isothermal Amplification of DNA and RNA by Using Self-Avoiding Molecular Recognition Systems.

    Science.gov (United States)

    Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M; Hoshika, Shuichi; Frye, Carole B; Benner, Steven A

    2015-06-15

    Assays that detect DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low-resource environments, and requires equipment and power that might not be available in these environments. Isothermal procedures, which avoid thermal cycling, are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a "self avoiding molecular recognition system" (SAMRS) eliminates these artifacts and gives clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3'-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, difficult to achieve with HDA using standard primers. Thus, SAMRS-HDA is a more versatile approach than standard HDA, with a broader applicability for xNA-targeted diagnostics and research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The influence of constitutional isomerism and change on molecular recognition processes.

    Science.gov (United States)

    Williams, Avril R; Northrop, Brian H; Houk, Kendall N; Stoddart, J Fraser; Williams, David J

    2004-10-25

    Three constitutionally isomeric bis(naphthylmethyl)ammonium ions, in which the two naphthyl groups are substituted 1) both at their 1-positions, 2) one at its 1-position and the other at its 2-position, and 3) both at their 2-positions, have been investigated separately in solution for their propensities to undergo spontaneous self-assembly with three different [24]crown-8 derivatives, namely, pyrido[24]crown-8 (P24C8), dipyrido[24]crown-8 (DP24C8) and dibenzo[24]crown-8 (DB24C8), in turn to form [2]pseudorotaxanes. The strengths of the 1:1 complexes depend on the composition of the secondary dialkylammonium ions and on the nature of the crown ether hosts; generally, as far as the guest cation is concerned, the 1/1- and 2/2-isomers form stronger complexes, as indicated by stability constant measurements, than the 1/2-isomer and, as far as the crown ethers are concerned, the more flexible P24C8 is a much more efficient host than either DP24C8 or DB24C8. The rates of formation of the [2]pseudorotaxanes are fast (i.e., taking no more than a few minutes) in solution with the exception of one case, that is, in which the crown ether host is DB24C8 and the guest cation is the 1/1-isomer, when it can take upwards of one month for the complexation-decomplexation equilibrium to be established at room temperature. In all cases, the equilibrium between complexed and uncomplexed species is slow on the NMR timescale, allowing the determination of stability constants to be made readily using the single-point method. X-ray crystallography and molecular modeling have been used to gain insight into ground and transition state interactions, respectively, in some of the [2]pseudorotaxanes. The relative stabilities of the three [2]pseudorotaxanes formed by each guest cation in the presence of the three crown ether hosts were also evaluated in solution by competition experiments that were monitored by (1)H NMR spectroscopy. By and large the results of the competition experiments could

  4. Molecular recognition of naphthalene diimide ligands by telomeric quadruplex-DNA: the importance of the protonation state and mediated hydrogen bonds.

    Science.gov (United States)

    Spinello, A; Barone, G; Grunenberg, J

    2016-01-28

    In depth Monte Carlo conformational scans in combination with molecular dynamics (MD) simulations and electronic structure calculations were applied in order to study the molecular recognition process between tetrasubstituted naphthalene diimide (ND) guests and G-quadruplex (G4) DNA receptors. ND guests are a promising class of telomere stabilizers due to which they are used in novel anticancer therapeutics. Though several ND guests have been studied experimentally in the past, the protonation state under physiological conditions is still unclear. Based on chemical intuition, in the case of N-methyl-piperazine substitution, different protonation states are possible and might play a crucial role in the molecular recognition process by G4-DNA. Depending on the proton concentration, different nitrogen atoms of the N-methyl-piperazine might (or might not) be protonated. This fact was considered in our simulation in terms of a case by case analysis, since the process of molecular recognition is determined by possible donor or acceptor positions. The results of our simulations show that the electrostatic interactions between the ND ligands and the G4 receptor are maximized in the case of the protonation of the terminal nitrogen atoms, forming compact ND G4 complexes inside the grooves. The influence of different protonation states in terms of the ability to form hydrogen bonds with the sugar-phosphate backbone, as well as the importance of mediated vs. direct hydrogen bonding, was analyzed in detail by MD and relaxed force constant (compliance constant) simulations.

  5. The menagerie of human lipocalins: a natural protein scaffold for molecular recognition of physiological compounds.

    Science.gov (United States)

    Schiefner, André; Skerra, Arne

    2015-04-21

    While immunoglobulins are well-known for their characteristic ability to bind macromolecular antigens (i.e., as antibodies during an immune response), the lipocalins constitute a family of proteins whose role is the complexation of small molecules for various physiological processes. In fact, a number of low-molecular-weight substances in multicellular organisms show poor solubility, are prone to chemical decomposition, or play a pathophysiological role and thus require specific binding proteins for transport through body fluids, storage, or sequestration. In many cases, lipocalins are involved in such tasks. Lipocalins are small, usually monomeric proteins with 150-180 residues and diameters of approximately 40 Å, adopting a compact fold that is dominated by a central eight-stranded up-and-down β-barrel. At the amino-terminal end, this core is flanked by a coiled polypeptide segment, while its carboxy-terminal end is followed by an α-helix that leans against the β-barrel as well as an amino acid stretch in a more-or-less extended conformation, which finally is fixed by a disulfide bond. Within the β-barrel, the antiparallel strands (designated A to H) are arranged in a (+1)7 topology and wind around a central axis in a right-handed manner such that part of strand A is hydrogen-bonded to strand H again. Whereas the lower region of the β-barrel is closed by short loops and densely packed hydrophobic side chains, including many aromatic residues, the upper end is usually open to solvent. There, four long loops, each connecting one pair of β-strands, together form the entrance to a cup-shaped cavity. Depending on the individual structure of a lipocalin, and especially on the lengths and amino acid sequences of its four loops, this pocket can accommodate chemical ligands of various sizes and shapes, including lipids, steroids, and other chemical hormones as well as secondary metabolites such as vitamins, cofactors, or odorants. While lipocalins are ubiquitous in

  6. Molecular insights on the recognition of a Lactococcus lactis cell wall pellicle by the phage 1358 receptor binding protein.

    Science.gov (United States)

    Farenc, Carine; Spinelli, Silvia; Vinogradov, Evgeny; Tremblay, Denise; Blangy, Stéphanie; Sadovskaya, Irina; Moineau, Sylvain; Cambillau, Christian

    2014-06-01

    The Gram-positive bacterium Lactococcus lactis is used for the production of cheeses and other fermented dairy products. Accidental infection of L. lactis cells by virulent lactococcal tailed phages is one of the major risks of fermentation failures in industrial dairy factories. Lactococcal phage 1358 possesses a host range limited to a few L. lactis strains and strong genomic similarities to Listeria phages. We report here the X-ray structures of phage 1358 receptor binding protein (RBP) in complex with monosaccharides. Each monomer of its trimeric RBP is formed of two domains: a "shoulder" domain linking the RBP to the rest of the phage and a jelly roll fold "head/host recognition" domain. This domain harbors a saccharide binding crevice located in the middle of a monomer. Crystal structures identified two sites at the RBP surface, ∼8 Å from each other, one accommodating a GlcNAc monosaccharide and the other accommodating a GlcNAc or a glucose 1-phosphate (Glc1P) monosaccharide. GlcNAc and GlcNAc1P are components of the polysaccharide pellicle that we identified at the cell surface of L. lactis SMQ-388, the host of phage 1358. We therefore modeled a galactofuranose (Galf) sugar bridging the two GlcNAc saccharides, suggesting that the trisaccharidic motif GlcNAc-Galf-GlcNAc (or Glc1P) might be common to receptors of genetically distinct lactococcal phages p2, TP091-1, and 1358. Strain specificity might therefore be elicited by steric clashes induced by the remaining components of the pellicle hexasaccharide. Taken together, these results provide a first insight into the molecular mechanism of host receptor recognition by lactococcal phages. Siphophages infecting the Gram-positive bacterium Lactococcus lactis are sources of milk fermentation failures in the dairy industry. We report here the structure of the pellicle polysaccharide from L. lactis SMQ-388, the specific host strain of phage 1358. We determined the X-ray structures of the lytic lactococcal phage

  7. Metal-Based Systems for Molecular Imaging Applications - COST D38 Annual Workshop - Scientific Program and Abstracts

    International Nuclear Information System (INIS)

    Mikolajczak, R.

    2009-01-01

    The main objective of the Action is the development of metal-based imaging probes for cellular and molecular imaging applications, based on MRI, PET, SPECT and optical imaging that will facilitate early diagnosis, assessment of disease progression and treatment evaluation.The goal of this Action is to further the development of innovative imaging probes through the pursuit of innovations in a number of different areas, ranging from the design of imaging units endowed with enhanced sensitivity to the control of the structural and electronic determinants responsible for the molecular recognition of the target molecule.At present, in vivo diagnostic systems basically assess the structure and function of human organs. Therefore, for important diseases such as cancer and cardiovascular pathologies,and also diseases of the central nervous system, only the late symptoms are detected. It is expected that the advances in genomics and proteomics will have a tremendous impact on human health care of the future. However, advances in molecular biology are already redefining diseases in terms of molecular abnormalities. With this knowledge, new generations of diagnostic imaging agents can be defined that aim at the detection of those molecular processes in vivo.The molecular imaging approach offers a great potential for earlier detection and characterisation of disease, and evaluation of treatment. However, more research is necessary to bring these ideas to clinical applications and a key aspect relates to the development of high-specificity, high-sensitivity imaging probes for the different detection modalities. Additionally, the Action includes research activities dealing with the exploitation of peculiar nuclear properties of given isotopes for therapeutic effects, thus integrating the diagnostic and the therapeutic stages.Apart from its use in early diagnosis in clinical practice, the molecular imaging approach will have also a major impact on the development of new

  8. Environmental Research Division: fundamental molecular physics and chemistry. Annual report, January-December 1983. Part I

    International Nuclear Information System (INIS)

    1985-03-01

    Research progress is reported in the following areas: (1) photoionization of radicals or excited states; (2) molecular spectroscopy by resonant multiphoton ionization; (3) studies conducted with the synchrotron radiation facility at the National Bureau of Standards; (4) theoretical studies on molecular photoabsorption; (5) analysis of photoabsorption spectra of open-shell atoms; (6) the electron energy-loss spectra of molecules; and (7) cross sections and stopping powers. Items have been individually abstracted for the data base

  9. Environmental Research Division: fundamental molecular physics and chemistry. Annual report, January-December 1983. Part I

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-01

    Research progress is reported in the following areas: (1) photoionization of radicals or excited states; (2) molecular spectroscopy by resonant multiphoton ionization; (3) studies conducted with the synchrotron radiation facility at the National Bureau of Standards; (4) theoretical studies on molecular photoabsorption; (5) analysis of photoabsorption spectra of open-shell atoms; (6) the electron energy-loss spectra of molecules; and (7) cross sections and stopping powers. Items have been individually abstracted for the data base. (ACR)

  10. Synergetic dual recognition and separation of the fungicide carbendazim by using magnetic nanoparticles carrying a molecularly imprinted polymer and immobilized β-cyclodextrin

    International Nuclear Information System (INIS)

    Li, Shuhuai; Wu, Xuejin; Zhang, Qun; Li, Pingping

    2016-01-01

    The authors describe a nanomaterial for solid-phase extraction of carbendazim. Magnetic molecularly imprinted polymer nanoparticles (mag-MIP-NPs) were obtained by immobilizing the MIP and a thiolated β-cyclodextrin on the surface of magnetite (Fe_3O_4) nanoparticles coated with gold nanoparticles. Both the recognition sites of the MIP and the hydrophobic cavities in the β-cyclodextrin contribute to the specific molecular recognition and extraction of carbendazim. The mag-MIP-NPs have an apparent adsorption capacity of 190 mg⋅g"-"1. Spiked vegetables were analyzed by using this material for extraction of carbendazim prior to its determination by ultra performance liquid chromatography (UHPLC). Recoveries range from 90.5 % to 109 %, and the detection limit is 3.0 pg⋅mL"-"1. (author)

  11. Engineering of an Extremely Thermostable Alpha/Beta Barrel Scaffold to Serve as a High Affinity Molecular Recognition Element for Use in Sensor Applications

    Science.gov (United States)

    2015-12-23

    Molecular Recognition Element For Use in Sensor Applications Report Title The overall goal of the project was to evolve a highly thermostable enzyme ( alcohol ...SECURITY CLASSIFICATION OF: The overall goal of the project was to evolve a highly thermostable enzyme ( alcohol dehydrogenase D (AdhD) from Pyrococcus...furiosus) to bind an explosive molecule, RDX. The enzyme naturally catalyzes the nicotinamide cofactor-dependent oxidation or reduction of alcohols

  12. Molecularly imprinted nanoparticles with recognition properties towards a laminin H-Tyr-Ile-Gly-Ser-Arg-OH sequence for tissue engineering applications

    International Nuclear Information System (INIS)

    Rosellini, Elisabetta; Barbani, Niccoletta; Giusti, Paolo; Ciardelli, Gianluca; Cristallini, Caterina

    2010-01-01

    Nanotechnology is an emerging field that promises to revolutionize medicine and is increasingly used in tissue engineering applications. Our research group proposed for the first time molecular imprinting as a new nanotechnology for the creation of advanced synthetic support structures for cell adhesion and proliferation. The aim of this work was the synthesis and characterization of molecularly imprinted polymers with recognition properties towards a laminin peptide sequence and their application as functionalization structures in the development of bioactive materials. Nanoparticles with an average diameter of 200 nm were synthesized by precipitation polymerization of methacrylic acid in the presence of the template molecule and trimethylpropane trimethacrylate as the cross-linking agent. The imprinted nanoparticles showed good performance in terms of recognition capacity and selectivity. The cytotoxicity tests showed normal vitality of C2C12 myoblasts cultured in the medium that was put in contact with the imprinted polymers. After the deposition on the polymeric film surface, the imprinted particles maintained their specific recognition and rebinding behaviour, showing an even higher quantitative binding than free nanoparticles. Preliminary in vitro cell culture tests demonstrated the ability of functionalized materials to promote cell adhesion, proliferation and differentiation, suggesting that molecular imprinting can be used as an innovative functionalization technique.

  13. Exploring the molecular basis of dsRNA recognition by NS1 protein of influenza A virus using molecular dynamics simulation and free energy calculation.

    Science.gov (United States)

    Pan, Dabo; Sun, Huijun; Shen, Yulin; Liu, Huanxiang; Yao, Xiaojun

    2011-12-01

    The frequent outbreak of influenza pandemic and the limited available anti-influenza drugs highlight the urgent need for the development of new antiviral drugs. The dsRNA-binding surface of nonstructural protein 1 of influenza A virus (NS1A) is a promising target. The detailed understanding of NS1A-dsRNA interaction will be valuable for structure-based anti-influenza drug discovery. To characterize and explore the key interaction features between dsRNA and NS1A, molecular dynamics simulation combined with MM-GBSA calculations were performed. Based on the MM-GBSA calculations, we find that the intermolecular van der Waals interaction and the nonpolar solvation term provide the main driving force for the binding process. Meanwhile, 17 key residues from NS1A were identified to be responsible for the dsRNA binding. Compared with the wild type NS1A, all the studied mutants S42A, T49A, R38A, R35AR46A have obvious reduced binding free energies with dsRNA reflecting in the reduction of the polar and/or nonpolar interactions. In addition, the structural and energy analysis indicate the mutations have a small effect to the backbone structures but the loss of side chain interactions is responsible for the decrease of the binding affinity. The uncovering of NS1A-dsRNA recognition mechanism will provide some useful insights and new chances for the development of anti-influenza drugs. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Microwave-assisted RAFT polymerization of well-constructed magnetic surface molecularly imprinted polymers for specific recognition of benzimidazole residues

    Science.gov (United States)

    Chen, Fangfang; Wang, Jiayu; Chen, Huiru; Lu, Ruicong; Xie, Xiaoyu

    2018-03-01

    Magnetic nanoparticles have been widely used as support core for fast separation, which could be directly separated from complicated matrices using an external magnet in few minutes. Surface imprinting based on magnetic core has shown favorable adsorption and separation performance, including good adsorption capacity, fast adsorption kinetics and special selectivity adsorption. Reversible addition-fragmentation chain transfer (RAFT) is an ideal choice for producing well-defined complex architecture with mild reaction conditions. We herein describe the preparation of well-constructed magnetic molecularly imprinted polymers (MMIPs) for the recognition of benzimidazole (BMZ) residues via the microwave-assisted RAFT polymerization. The merits of RAFT polymerization assisting with microwave heating allowed successful and more efficient preparation of well-constructed imprinted coats. Moreover, the polymerization time dramatically shortened and was just 1/24th of the time taken by conventional heating. The results indicated that a uniform nanoscale imprinted layer was formed on the Fe3O4 core successfully, and enough saturation magnetization of MMIPs (16.53 emu g-1) was got for magnetic separation. The desirable adsorption capacity (30.18 μmol g-1) and high selectivity toward template molecule with a selectivity coefficient (k) of 13.85 of MMIPs were exhibited by the adsorption isothermal assay and competitive binding assay, respectively. A solid phase extraction enrichment approach was successfully established for the determination of four BMZ residues from apple samples using MMIPs coupled to HPLC. Overall, this study provides a versatile approach for highly efficient fabrication of well-constructed MMIPs for enrichment and determination of target molecules from complicated samples.

  15. Molecular Modeling Study of Chiral Separation and Recognition Mechanism of β-Adrenergic Antagonists by Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Yifeng Chai

    2012-01-01

    Full Text Available Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol were studied by capillary electrophoresis using six cyclodextrins (CDs as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the –OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.

  16. Rapid Colorimetric Detection of Cartap Residues by AgNP Sensor with Magnetic Molecularly Imprinted Microspheres as Recognition Elements

    Directory of Open Access Journals (Sweden)

    Mao Wu

    2018-06-01

    Full Text Available The overuse of cartap in tea tree leads to hazardous residues threatening human health. A colorimetric determination was established to detect cartap residues in tea beverages by silver nanoparticles (AgNP sensor with magnetic molecularly imprinted polymeric microspheres (Fe3O4@mSiO2@MIPs as recognition elements. Using Fe3O4 as supporting core, mesoporous SiO2 as intermediate shell, methylacrylic acid as functional monomer, and cartap as template, Fe3O4@mSiO2@MIPs were prepared to selectively and magnetically separate cartap from tea solution before colorimetric determination by AgNP sensors. The core-shell Fe3O4@mSiO2@MIPs were also characterized by FT-IR, TEM, VSM, and experimental adsorption. The Fe3O4@mSiO2@MIPs could be rapidly separated by an external magnet in 10 s with good reusability (maintained 95.2% through 10 cycles. The adsorption process of cartap on Fe3O4@mSiO2@MIPs conformed to Langmuir adsorption isotherm with maximum adsorption capacity at 0.257 mmol/g and short equilibrium time of 30 min at 298 K. The AgNP colorimetric method semi-quantified cartap ≥5 mg/L by naked eye and quantified cartap 0.1–5 mg/L with LOD 0.01 mg/L by UV-vis spectroscopy. The AgNP colorimetric detection after pretreatment with Fe3O4@mSiO2@MIPs could be successfully utilized to recognize and detect cartap residues in tea beverages.

  17. Abstracts of the 30. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    2001-01-01

    Several aspects concerning biochemistry and molecular biology of either animals, plants and microorganisms are studied. Topics such as cell membrane structures (including receptors), enzymatic assays, biological pathways, structural chemical analysis, metabolism, biological functions are focused. The use of radiolabelled compounds (radioassay, radioreceptor assay) and nuclear magnetic resonance are the most applied techniques

  18. Abstracts of the 29. annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    2000-01-01

    Several aspects concerning biochemistry and molecular biology of either animals (including man), plants and microorganisms are studied. Topics such as cell membrane structures (including receptors), enzymatic assays, biological pathways, structural chemical analysis, metabolism, biological functions are focused. The use of radiolabelled compounds (radioassay, radioenzymatic assay, radioreceptor assay and nuclear magnetic resonance are the most applied techniques

  19. Abstracts of the 28. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    1999-01-01

    Biochemistry, genetic and molecular biology aspects of either animals (including man), plants and microorganisms are studied. Topics such as cell membrane structures (including receptors), enzymatic assays, biological pathways, structural chemical analysis, metabolism, biological functions are focused. The use of radiolabelled compounds (radioassay, radioenzymatic assay, radioreceptor assay) and nuclear magnetic resonance are the most applied techniques

  20. Energy-related atomic and molecular structure and scattering studies. Annual report, June 1, 1985-May 31, 1986

    International Nuclear Information System (INIS)

    Bederson, B.

    1986-01-01

    This is the Annual Report for the period June 1, 1985 to May 31, 1986 for ''Energy-Related Atomic and Molecular Structure and Scattering Studies''. During the past year our efforts were concentrated on two specific experiments. These were (1) an attempt to measure the polarizability of the optically pumped excited state of thallium 6s6p 2 P/sub 3/2/, including its tensor components, and (2) a study of the differential scattering at small angles of electrons at low energies by several alkali halide molecules. In the thallium experiment we have performed some preliminary measurements, although we have temporarily discontinued these in order to update the beams machine upon which this experiment is being performed. 13 refs., 16 figs

  1. Following are the abstracts from the Fourth Annual Meeting of the Society for Molecular Imaging

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available Declaration of Financial Interests or Relationships To insure balance, independence, objectivity and scientific rigor in all CME programs it is the policy of the meeting's joint sponsors that any speaker or poster presenter who makes a presentation at a program designated for AMA Physician's Recognition Award (PRA Category 1 or 2 credit must disclose any real or apparent financial interest or other relationship (i.e., grants, research support, consultant, honoraria that the presenter may have with the manufacturers, distributors or providers of any commercial products or services that may be discussed in the presentation. ISMRM and SMI do not imply that such financial interests or relationships are inherently improper or that such interests or relationships would prevent the presenter from making an objective presentation. However, it is imperative that such financial interests or relationships be identified by the presenter so that participants at the CME activity may have these facts fully disclosed prior to the presentation, and may form their own judgments about the presentation. Towards this end, the information provided by each presenter can be found at the bottom of each abstract. Every speaker, abstract presenter, organizer or anyone else who has control over any content in this meeting has been required to submit a Declaration of Financial Interests or Relationships, even if there is no conflict or relationship to declare.

  2. Preparation of molecularly imprinted nanoparticles with superparamagnetic susceptibility through atom transfer radical emulsion polymerization for the selective recognition of tetracycline from aqueous medium

    International Nuclear Information System (INIS)

    Dai, Jiangdong; Pan, Jianming; Xu, Longcheng; Li, Xiuxiu; Zhou, Zhiping; Zhang, Rongxian; Yan, Yongsheng

    2012-01-01

    Highlights: ► Atom transfer radical emulsion polymerization is a “living” and green technique. ► Nanoparticles can overcome mass transfer limitations and improve accessibility. ► Molecular imprinted nanoparticles with magnetic property for fast separation. ► The performance of imprinted nanoparticles was investigated in detail. ► Nanoparticles were used to selective recognize Tetracycline from water medium. - Abstract: In the work, we reported an effective method for the preparation of molecularly imprinted nanoparticles with superparamagnetic susceptibility through atom transfer radical emulsion polymerization (ATREP), and then as-prepared magnetic molecularly imprinted nanoparticles (MMINs) were evaluated as adsorbents for selective recognition of tetracycline (TC) molecules from aqueous medium. The resulting nanoparticles were characterized by FT-IR, TGA, VSM, SEM and TEM. The results demonstrated MMINs with a narrow diameter distribution were cross-linked with modified Fe 3 O 4 particles, composed of imprinted layer and exhibited good magnetic sensitivity, magnetic and thermal stability. Batch rebinding studies were carried out to determine the specific adsorption equilibrium, kinetics, and selective recognition. The estimated adsorption capacity of MMINs towards TC by the Langmuir isotherm model was 12.10 mg g −1 at 298 K, which was 6.33 times higher than that of magnetic non-molecularly imprinted nanoparticles (MNINs). The kinetic property of MMINs was well-described by the pseudo-second-order rate equation. The results of selective recognition experiments demonstrated outstanding affinity and selectivity towards TC over competitive antibiotics. The reusability of MMINs showed no obviously deterioration at least five repeated cycles in performance. In addition, the MMINs prepared were successfully applied to the extraction of TC from the spiked pork sample.

  3. Preparation of molecularly imprinted nanoparticles with superparamagnetic susceptibility through atom transfer radical emulsion polymerization for the selective recognition of tetracycline from aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jiangdong; Pan, Jianming; Xu, Longcheng; Li, Xiuxiu [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Zhiping [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhang, Rongxian [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yan, Yongsheng, E-mail: djdxxx123@163.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, 100191 (China)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Atom transfer radical emulsion polymerization is a 'living' and green technique. Black-Right-Pointing-Pointer Nanoparticles can overcome mass transfer limitations and improve accessibility. Black-Right-Pointing-Pointer Molecular imprinted nanoparticles with magnetic property for fast separation. Black-Right-Pointing-Pointer The performance of imprinted nanoparticles was investigated in detail. Black-Right-Pointing-Pointer Nanoparticles were used to selective recognize Tetracycline from water medium. - Abstract: In the work, we reported an effective method for the preparation of molecularly imprinted nanoparticles with superparamagnetic susceptibility through atom transfer radical emulsion polymerization (ATREP), and then as-prepared magnetic molecularly imprinted nanoparticles (MMINs) were evaluated as adsorbents for selective recognition of tetracycline (TC) molecules from aqueous medium. The resulting nanoparticles were characterized by FT-IR, TGA, VSM, SEM and TEM. The results demonstrated MMINs with a narrow diameter distribution were cross-linked with modified Fe{sub 3}O{sub 4} particles, composed of imprinted layer and exhibited good magnetic sensitivity, magnetic and thermal stability. Batch rebinding studies were carried out to determine the specific adsorption equilibrium, kinetics, and selective recognition. The estimated adsorption capacity of MMINs towards TC by the Langmuir isotherm model was 12.10 mg g{sup -1} at 298 K, which was 6.33 times higher than that of magnetic non-molecularly imprinted nanoparticles (MNINs). The kinetic property of MMINs was well-described by the pseudo-second-order rate equation. The results of selective recognition experiments demonstrated outstanding affinity and selectivity towards TC over competitive antibiotics. The reusability of MMINs showed no obviously deterioration at least five repeated cycles in performance. In addition, the MMINs prepared were successfully

  4. Molecular recognition in a diverse set of protein-ligand interactions studied with molecular dynamics simulations and end-point free energy calculations.

    Science.gov (United States)

    Wang, Bo; Li, Liwei; Hurley, Thomas D; Meroueh, Samy O

    2013-10-28

    End-point free energy calculations using MM-GBSA and MM-PBSA provide a detailed understanding of molecular recognition in protein-ligand interactions. The binding free energy can be used to rank-order protein-ligand structures in virtual screening for compound or target identification. Here, we carry out free energy calculations for a diverse set of 11 proteins bound to 14 small molecules using extensive explicit-solvent MD simulations. The structure of these complexes was previously solved by crystallography and their binding studied with isothermal titration calorimetry (ITC) data enabling direct comparison to the MM-GBSA and MM-PBSA calculations. Four MM-GBSA and three MM-PBSA calculations reproduced the ITC free energy within 1 kcal·mol(-1) highlighting the challenges in reproducing the absolute free energy from end-point free energy calculations. MM-GBSA exhibited better rank-ordering with a Spearman ρ of 0.68 compared to 0.40 for MM-PBSA with dielectric constant (ε = 1). An increase in ε resulted in significantly better rank-ordering for MM-PBSA (ρ = 0.91 for ε = 10), but larger ε significantly reduced the contributions of electrostatics, suggesting that the improvement is due to the nonpolar and entropy components, rather than a better representation of the electrostatics. The SVRKB scoring function applied to MD snapshots resulted in excellent rank-ordering (ρ = 0.81). Calculations of the configurational entropy using normal-mode analysis led to free energies that correlated significantly better to the ITC free energy than the MD-based quasi-harmonic approach, but the computed entropies showed no correlation with the ITC entropy. When the adaptation energy is taken into consideration by running separate simulations for complex, apo, and ligand (MM-PBSAADAPT), there is less agreement with the ITC data for the individual free energies, but remarkably good rank-ordering is observed (ρ = 0.89). Interestingly, filtering MD snapshots by prescoring

  5. Fundamental molecular physics and chemistry. Radiological and Environmental Research Division annual report, October 1981-December 1982. Pt. 1

    International Nuclear Information System (INIS)

    1983-12-01

    This document is the twelfth Annual Report of our Fundamental Molecular Physics and Chemistry Program. Scientifically, the work of the program deals with aspects of the physics and chemistry of molecules related to their interactions with photons, electrons, and other external agents. We chose these areas of study in view of our matic goals; that is to say, we chose them so that the eventual outcome of our work meets some of the needs of the US Department of Energy (DOE) and of other government agencies that support our research. First, we endeavor to determine theoretically and experimentally cross sections for electron and photon interactions with molecules, because those cross sections are indispensable for detailed microscopic analyses of the earliest processes of radiation action on any molecular substance, including biological materials. Those analyses in turn provide a sound basis for radiology and radiation dosimetry. Second, we study the spectroscopy of certain molecules and of small clusters of molecules because this topic is fundamental to the full understanding of atmospheric-pollutant chemistry

  6. Fundamental molecular physics and chemistry. Radiological and Environmental Research Division annual report, October 1981-December 1982. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    1983-12-01

    This document is the twelfth Annual Report of our Fundamental Molecular Physics and Chemistry Program. Scientifically, the work of the program deals with aspects of the physics and chemistry of molecules related to their interactions with photons, electrons, and other external agents. We chose these areas of study in view of our matic goals; that is to say, we chose them so that the eventual outcome of our work meets some of the needs of the US Department of Energy (DOE) and of other government agencies that support our research. First, we endeavor to determine theoretically and experimentally cross sections for electron and photon interactions with molecules, because those cross sections are indispensable for detailed microscopic analyses of the earliest processes of radiation action on any molecular substance, including biological materials. Those analyses in turn provide a sound basis for radiology and radiation dosimetry. Second, we study the spectroscopy of certain molecules and of small clusters of molecules because this topic is fundamental to the full understanding of atmospheric-pollutant chemistry.

  7. Chiral Recognition in Molecular and Macromolecular Pairs of(S)- and (R)- 1-Cyano-2-Methylpropyl 4’((4-(8-Vinyloxyoctyloxy)Benzoyl) Biphenyl-4-Carboxylate Enantiomers

    Science.gov (United States)

    1994-06-30

    above please provide a graphical abstract of the paper ar, return it to the Editorial Office as soon as possible. 4oeg0 o F-99S or TS A& I DTI•’ I J. u1...TCLSICAON 2.LIMITATION OF ABSTRAC •F oFPORT OF THIS PAGE OF ABSTRACT . unclass ified Graphical Abstracts for Perkin Txans. 1 Example TITLE GRAPHICAL ... ABSTRACT AUTHORS’ N AMES Template (S)-II Chiral recognition in molecular and . -- macromolecular pairs of (S)- and -- (R)-i-cyano-2-methyipropyl 4’-{[4

  8. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

    OpenAIRE

    Stojković, Marijana Radić; Škugor, Marko; Dudek, Łukasz; Grolik, Jarosław; Eilmes, Julita; Piantanida, Ivo

    2014-01-01

    Summary An investigation of the interactions of two novel and several known DBTAA–adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA–propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure–activity...

  9. Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

    Science.gov (United States)

    Stojković, Marijana Radić; Škugor, Marko; Dudek, Łukasz; Grolik, Jarosław; Eilmes, Julita

    2014-01-01

    Summary An investigation of the interactions of two novel and several known DBTAA–adenine conjugates with double-stranded DNA and RNA has revealed the DNA/RNA groove as the dominant binding site, which is in contrast to the majority of previously studied DBTAA analogues (DNA/RNA intercalators). Only DBTAA–propyladenine conjugates revealed the molecular recognition of AT-DNA by an ICD band pattern > 300 nm, whereas significant ICD bands did not appear for other ds-DNA/RNA. A structure–activity relation for the studied series of compounds showed that the essential structural features for the ICD recognition are a) the presence of DNA-binding appendages (adenine side chain and positively charged side chain) on both DBTAA side chains, and b) the presence of a short propyl linker, which does not support intramolecular aromatic stacking between DBTAA and adenine. The observed AT-DNA-ICD pattern differs from previously reported ss-DNA (poly dT) ICD recognition by a strong negative ICD band at 350 nm, which allows for the dynamic differentiation between ss-DNA (poly dT) and coupled ds-AT-DNA. PMID:25246976

  10. Fluorescence and room temperature phosphorescence of 6-bromo-2-naphthol in {beta}-cyclodextrin solution and its selective molecular recognition for cyclohexane

    Energy Technology Data Exchange (ETDEWEB)

    Zhai Yanqiang; Zhang Shuzhen; Xie Jianwei; Liu Changsong

    2003-10-08

    The room temperature phosphorescence (RTP) and fluorescence behavior of 6-bromo-2-naphthol (BN) in water and {beta}-cyclodextrin ({beta}-CD) aerated aqueous solution was investigated. The study of fluorescence behavior at different pH values indicated that three kinds of species of BN (protonated, uncharged and anionic species) formed 1:1 inclusion complexes with {beta}-CD, and RTP and fluorescence emission depended on the pH of the solution. The inclusion complex constants were 430{+-}25 l mol{sup -1} (pH 1.80), 840{+-}25 l mol{sup -1} (pH 5.80), 1850{+-}75 l mol{sup -1} (pH 11.50), respectively. Experimental results elucidated that RTP of the BN/{beta}-CD/cyclohexane solution came from the protonated and uncharged species of BN, but not from the anionic species, though the inclusion constant of the anionic species of BN with {beta}-CD was larger than that of the other two species of BN Selective molecular recognition of BN/{beta}-CD as an RTP sensor for 28 small organic molecules was studied, it was shown that BN/{beta}-CD could be develop as a new RTP sensor with high selectivity molecular recognition ability for cyclohexane.

  11. Fluorescence and room temperature phosphorescence of 6-bromo-2-naphthol in β-cyclodextrin solution and its selective molecular recognition for cyclohexane

    International Nuclear Information System (INIS)

    Zhai Yanqiang; Zhang Shuzhen; Xie Jianwei; Liu Changsong

    2003-01-01

    The room temperature phosphorescence (RTP) and fluorescence behavior of 6-bromo-2-naphthol (BN) in water and β-cyclodextrin (β-CD) aerated aqueous solution was investigated. The study of fluorescence behavior at different pH values indicated that three kinds of species of BN (protonated, uncharged and anionic species) formed 1:1 inclusion complexes with β-CD, and RTP and fluorescence emission depended on the pH of the solution. The inclusion complex constants were 430±25 l mol -1 (pH 1.80), 840±25 l mol -1 (pH 5.80), 1850±75 l mol -1 (pH 11.50), respectively. Experimental results elucidated that RTP of the BN/β-CD/cyclohexane solution came from the protonated and uncharged species of BN, but not from the anionic species, though the inclusion constant of the anionic species of BN with β-CD was larger than that of the other two species of BN Selective molecular recognition of BN/β-CD as an RTP sensor for 28 small organic molecules was studied, it was shown that BN/β-CD could be develop as a new RTP sensor with high selectivity molecular recognition ability for cyclohexane

  12. Interconnectivity of macroporous molecularly imprinted polymers fabricated by hydroxyapatite-stabilized Pickering high internal phase emulsions-hydrogels for the selective recognition of protein.

    Science.gov (United States)

    Sun, Yanhua; Li, Yuqing; Xu, Jiangfeng; Huang, Ling; Qiu, Tianyun; Zhong, Shian

    2017-07-01

    Hydroxyapatite hybridized molecularly imprinted polydopamine polymers with selective recognition of bovine hemoglobin (BHb) were successfully prepared via Pickering oil-in-water high internal phase emulsions-hydrogels and molecularly imprinting technique. The emulsions were stabilized by hydroxyapatite of which the wettability was modified by 3-methacryloxypropyltrimethoxysilane. The materials were characterized by SEM, IR and TGA. The results showed that the BHb imprinted polymers based on Pickering hydrogels (Hydro-MIPs) possess macropores ranging from 20μm to 50μm, and their large numbers of amino groups and hydroxyl groups result in a favorable adsorption capacity for BHb. The maximum adsorption capacity of Hydro-MIPs for BHb was 438mg/g, 3.27 times more than that of the non-imprinted polymers (Hydro-NIPs). The results indicated that Hydro-MIPs possessing well-defined hierarchical porous structures exhibited outstanding recognition behavior towards the target protein molecules. This work provided a promising alternative method for the fabrication of polymer materials with tunable and interconnected pores structures for the separation and purification of protein in vitro. Copyright © 2017. Published by Elsevier B.V.

  13. Proceedings of the forty third annual conference of Society of Nuclear Medicine India: empowering modern medicine with molecular nuclear medicine

    International Nuclear Information System (INIS)

    2011-01-01

    Theme of the 43rd Annual Conference of the Society of Nuclear Medicine India is 'empowering modem medicine with molecular nuclear medicine'. Keeping the theme in mind, the scientific committee has arranged an attractive and comprehensive program for both physicians and scientists reflecting the multimodality background of Nuclear Medicine and Metabolic Imaging. During this meeting the present status and future prospects of Nuclear medicine are discussed at length by esteemed faculty in dedicated symposia and interesting featured sessions which are immensely facilitate in educating the participants. Nuclear Medicine has come a long way since the first applications of radioiodine in the diagnosis of thyroid disease. The specialty of nuclear medicine in India is growing very rapidly. Technology continues to push the field in new directions and open new pathways for providing optimal care to patients. It is indeed an exciting time in the world of imaging and in the field of nuclear medicine. Innovative techniques in hardware and software offer advantages for enhanced accuracy. New imaging agents, equipment, and software will provide us with new opportunities to improve current practices and to introduce new technology into the clinical protocols. Papers relevant to INIS are indexed separately

  14. Molecular Evolution of the CYP2D Subfamily in Primates: Purifying Selection on Substrate Recognition Sites without the Frequent or Long-Tract Gene Conversion

    Science.gov (United States)

    Yasukochi, Yoshiki; Satta, Yoko

    2015-01-01

    The human cytochrome P450 (CYP) 2D6 gene is a member of the CYP2D gene subfamily, along with the CYP2D7P and CYP2D8P pseudogenes. Although the CYP2D6 enzyme has been studied extensively because of its clinical importance, the evolution of the CYP2D subfamily has not yet been fully understood. Therefore, the goal of this study was to reveal the evolutionary process of the human drug metabolic system. Here, we investigate molecular evolution of the CYP2D subfamily in primates by comparing 14 CYP2D sequences from humans to New World monkey genomes. Window analysis and statistical tests revealed that entire genomic sequences of paralogous genes were extensively homogenized by gene conversion during molecular evolution of CYP2D genes in primates. A neighbor-joining tree based on genomic sequences at the nonsubstrate recognition sites showed that CYP2D6 and CYP2D8 genes were clustered together due to gene conversion. In contrast, a phylogenetic tree using amino acid sequences at substrate recognition sites did not cluster the CYP2D6 and CYP2D8 genes, suggesting that the functional constraint on substrate specificity is one of the causes for purifying selection at the substrate recognition sites. Our results suggest that the CYP2D gene subfamily in primates has evolved to maintain the regioselectivity for a substrate hydroxylation activity between individual enzymes, even though extensive gene conversion has occurred across CYP2D coding sequences. PMID:25808902

  15. Selective separation of hydroxy polychlorinated biphenyls (HO-PCBs) by the structural recognition on the molecularly imprinted polymers: Direct separation of the thyroid hormone active analogues from mixtures

    International Nuclear Information System (INIS)

    Kubo, Takuya; Matsumoto, Hideyuki; Shiraishi, Fujio; Nomachi, Makoto; Nemoto, Koji; Hosoya, Ken; Kaya, Kunimitsu

    2007-01-01

    We developed novel separation media for hydroxy polychlorinated biphenyls (HO-PCBs) using the molecular imprinting techniques. The results of evaluation for the molecularly imprinted polymers (MIPs) by the liquid chromatography (LC) suggested that MIPs had selective separation ability for certain HO-PCB analogues. The results of the LC evaluations and molecular modeling indicated that the molecular volumes and pK a values of template molecules were related with the retention factor of HO-PCBs. Additionally, according to the detail evaluation toward the selective separation behaviors of MIPs, these HO-PCB analogues have low pK a values dependent on their chemical structures. In other words, the prepared MIPs had selective recognition ability against the analogues, which have an OH group on a phenyl carbon and two chlorine atoms on the both neighboring carbons of the carbon attached with the OH group. Moreover, these analogues may have a potential for thyroid hormone activities so that we attempted to separate these analogues directly from mixtures of HO-PCBs using a prepared MIP

  16. Molecular cloning and functional characterization of peptidoglycan recognition protein OmPGRP-L2 from the rainbow trout, Oncorhynchus mykiss.

    Science.gov (United States)

    Jang, Ju Hye; Kim, Hyun; Cho, Ju Hyun

    2017-10-01

    Peptidoglycan recognition proteins (PGRPs), a group of pattern recognition receptors (PRRs), are innate immune molecules that are structurally conserved through evolution in both invertebrate and vertebrate animals. In teleost fish, several PGRPs have been characterized recently. They have both amidase activity and bactericidal activity and are involved in indirectly killing bacteria and regulating multiple signaling pathways. However, the knowledge of functional similarity and divergence between PGRP paralogs for their role as an immune modulator in teleost fish is still limited. In this study, we identified a novel PGRP paralog, termed OmPGRP-L2 from the rainbow trout (Oncorhynchus mykiss). OmPGRP-L2 contains the conserved PGRP domain and the four Zn 2+ -binding amino acid residues required for amidase activity. Quantitative RT-PCR analysis indicated that OmPGRP-L2 is highly expressed in liver. Overexpression of OmPGRP-L2 in a rainbow trout hepatocyte cell line RTH-149 challenged with Edwardsiella tarda resulted in down-regulation of IL-1β and TNF-α expression. When overexpressed in RTH-149 cells, OmPGRP-L2 inhibited NF-κB activity with or without bacterial stimulation. Collectively, these findings suggest that OmPGRP-L2 has an immunomodulatory function, via NF-κB inhibition in liver. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Molecular insights into the specific recognition between the RNA binding domain qRRM2 of hnRNP F and G-tract RNA: A molecular dynamics study.

    Science.gov (United States)

    Wang, Lingyun; Yan, Feng

    2017-12-09

    Heterogeneous nuclear ribonucleoprotein F (hnRNP F) controls the expression of various genes through regulating the alternative splicing of pre-mRNAs in the nucleus. It uses three quasi-RNA recognition motifs (qRRMs) to recognize G-tract RNA which contains at least three consecutive guanines. The structures containing qRRMs of hnRNP F in complex with G-tract RNA have been determined by nuclear magnetic resonance (NMR) spectroscopy, shedding light on the recognition mechanism of qRRMs with G-tract RNA. However, knowledge of the recognition details is still lacking. To investigate how qRRMs specifically bind with G-tract RNA and how the mutations of any guanine to an adenine in the G-tract affect the binding, molecular dynamics simulations with binding free energy analysis were performed based on the NMR structure of qRRM2 in complex with G-tract RNA. Simulation results demonstrate that qRRM2 binds strongly with G-tract RNA, but any mutation of the G-tract leads to a drastic reduction of the binding free energy. Further comparisons of the energetic components reveal that van der Waals and non-polar interactions play essential roles in the binding between qRRM2 and G-tract RNA, but the interactions are weakened by the effect of RNA mutations. Structural and dynamical analyses indicate that when qRRM2 binds with G-tract RNA, both qRRM2 and G-tract maintain stabilized structures and dynamics; however, the stability is disrupted by the mutations of the G-tract. These results provide novel insights into the recognition mechanism of qRRM2 with G-tract RNA that are not elucidated by the NMR technique. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Zipper-like magnetic molecularly imprinted microspheres for on/off-switchable recognition and extraction of 17β-estradiol from food samples.

    Science.gov (United States)

    Zhu, Wenting; Peng, Hailong; Luo, Mei; Yu, Ningxiang; Xiong, Hua; Wang, Ronghui; Li, Yanbin

    2018-09-30

    Zipper-like on/off-switchable and magnetic molecularly imprinted microspheres (SM-MIMs) were constructed using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers for 17β-estradiol (17β-E 2 ) recognition and extraction. The imprinted polymer interactions between poly(AAm) (PAAm) and poly(AMPS) (PAMPS) with on/off-switchable property to temperature, exhibited dissociation at relatively higher temperatures (such as 30 °C) and helped 17β-E 2 enter into imprinted sites, leading to higher binding capability. Conversely, the interpolymer complexes between PAAm and PAMPS formed and blocked 17β-E 2 access to imprinted sites at lower temperature (such as 20 °C). SM-MIMs were used as dispersive solid phase extraction (SPE) adsorbent with HPLC for 17β-E 2 pretreatment and detection in food samples, and low limit detection (2.52 µg L -1 ) and quantification (10.76 µg L -1 ) with higher recovery were obtained. Therefore, SM-MIMs may be a promising adsorbent for 17β-E 2 pretreatment in food samples owing to its advantages of on/off-switchable recognition, eco-friendly elution, and efficient separation. Copyright © 2018. Published by Elsevier Ltd.

  19. Molecularly imprinted polymer beads for nicotine recognition prepared by RAFT precipitation polymerization: a step forward towards multifunctionalities

    DEFF Research Database (Denmark)

    Zhou, Tongchang; Jørgensen, Lars; Mattebjerg, Maria Ahlm

    2014-01-01

    A nicotine imprinted polymer was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using methacrylic acid (MAA) as a functional monomer. The resulting molecularly imprinted polymers were monodispersed beads with an average diameter of 1.55 mm. The molecular...... selectivity of the imprinted polymer beads was evaluated by studying the uptake of nicotine and its structural analogs by the polymer beads. Equilibrium binding results indicate that the amount of nicotine bound to the imprinted polymer beads is significantly higher than that bound to the nonimprinted polymer...

  20. Charge pattern matching as a ‘fuzzy’ mode of molecular recognition for the functional phase separations of intrinsically disordered proteins

    Science.gov (United States)

    Lin, Yi-Hsuan; Brady, Jacob P.; Forman-Kay, Julie D.; Chan, Hue Sun

    2017-11-01

    Biologically functional liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is driven by interactions encoded by their amino acid sequences. Little is currently known about the molecular recognition mechanisms for distributing different IDP sequences into various cellular membraneless compartments. Pertinent physics was addressed recently by applying random-phase-approximation (RPA) polymer theory to electrostatics, which is a major energetic component governing IDP phase properties. RPA accounts for charge patterns and thus has advantages over Flory-Huggins (FH) and Overbeek-Voorn mean-field theories. To make progress toward deciphering the phase behaviors of multiple IDP sequences, the RPA formulation for one IDP species plus solvent is hereby extended to treat polyampholyte solutions containing two IDP species plus solvent. The new formulation generally allows for binary coexistence of two phases, each containing a different set of volume fractions ({φ }1,{φ }2) for the two different IDP sequences. The asymmetry between the two predicted coexisting phases with regard to their {φ }1/{φ }2 ratios for the two sequences increases with increasing mismatch between their charge patterns. This finding points to a multivalent, stochastic, ‘fuzzy’ mode of molecular recognition that helps populate various IDP sequences differentially into separate phase compartments. An intuitive illustration of this trend is provided by FH models, whereby a hypothetical case of ternary coexistence is also explored. Augmentations of the present RPA theory with a relative permittivity {ɛ }{{r}}(φ ) that depends on IDP volume fraction φ ={φ }1+{φ }2 lead to higher propensities to phase separate, in line with the case with one IDP species we studied previously. Notably, the cooperative, phase-separation-enhancing effects predicted by the prescriptions for {ɛ }{{r}}(φ ) we deem physically plausible are much more prominent than that entailed by common

  1. Molecular recognition at methyl methacrylate/n-butyl acrylate (MMA/nBA) monomer unit boundaries of phospholipids at p-MMA/nBA copolymer surfaces.

    Science.gov (United States)

    Yu, Min; Urban, Marek W; Sheng, Yinghong; Leszczynski, Jerzy

    2008-09-16

    Lipid structural features and their interactions with proteins provide a useful vehicle for further advances in membrane proteins research. To mimic one of potential lipid-protein interactions we synthesized poly(methyl methacrylate/ n-butyl acrylate) (p-MMA/nBA) colloidal particles that were stabilized by phospholipid (PLs). Upon the particle coalescence, PL stratification resulted in the formation of surface localized ionic clusters (SLICs). These entities are capable of recognizing MMA/nBA monomer interfaces along the p-MMA/nBA copolymer backbone and form crystalline SLICs at the monomer interface. By utilizing attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy and selected area electron diffraction (SAD) combined with ab initio calculations, studies were conducted that identified the origin of SLICs as well as their structural features formed on the surface of p-MMA/nBA copolymer films stabilized by 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) PL. Specific entities responsible for SLIC formation are selective noncovalent bonds of anionic phosphate and cationic quaternary ammonium segments of DLPC that interact with two neighboring carbonyl groups of nBA and MMA monomers of the p-MMA/nBA polymer backbone. To the best of our knowledge this is the first example of molecular recognition facilitated by coalescence of copolymer colloidal particles and the ability of PLs to form SLICs at the boundaries of the neighboring MMA and nBA monomer units of the p-MMA/nBA chain. The dominating noncovalent bonds responsible for the molecular recognition is a combination of H-bonding and electrostatic interactions.

  2. Use of UV-vis-NIR spectroscopy to monitor label-free interaction between molecular recognition elements and erythropoietin on a gold-coated polycarbonate platform.

    Science.gov (United States)

    Citartan, Marimuthu; Gopinath, Subash C B; Tominaga, Junji; Chen, Yeng; Tang, Thean-Hock

    2014-08-01

    Label-free-based detection is pivotal for real-time monitoring of biomolecular interactions and to eliminate the need for labeling with tags that can occupy important binding sites of biomolecules. One simplest form of label-free-based detection is ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, which measure changes in reflectivity as a means to monitor immobilization and interaction of biomolecules with their corresponding partners. In biosensor development, the platform used for the biomolecular interaction should be suitable for different molecular recognition elements. In this study, gold (Au)-coated polycarbonate was used as a platform and as a proof-of-concept, erythropoietin (EPO), a doping substance widely abused by the athletes was used as the target. The interaction of EPO with its corresponding molecular recognition elements (anti-EPO monoclonal antibody and anti-EPO DNA aptamer) is monitored by UV-vis-NIR spectroscopy. Prior to this, to show that UV-vis-NIR spectroscopy is a suitable method for measuring biomolecular interaction, the interaction between biotin and streptavidin was demonstrated via this strategy and reflectivity of this interaction decreased by 25%. Subsequent to this, interaction of the EPO with anti-EPO monoclonal antibody and anti-EPO DNA aptamer resulted in the decrease of reflectivity by 5% and 10%, respectively. The results indicated that Au-coated polycarbonate could be an ideal biosensor platform for monitoring biomolecular interactions using UV-vis-NIR spectroscopy. A smaller version of the Au-coated polycarbonate substrates can be derived from the recent set-up, to be applied towards detecting EPO abuse among atheletes. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. A malonitrile-functionalized metal-organic framework for hydrogen sulfide detection and selective amino acid molecular recognition

    Science.gov (United States)

    Li, Haiwei; Feng, Xiao; Guo, Yuexin; Chen, Didi; Li, Rui; Ren, Xiaoqian; Jiang, Xin; Dong, Yuping; Wang, Bo

    2014-03-01

    A novel porous polymeric fluorescence probe, MN-ZIF-90, has been designed and synthesized for quantitative hydrogen sulfide (H2S) fluorescent detection and highly selective amino acid recognition. This distinct crystalline structure, derived from rational design and malonitrile functionalization, can trigger significant enhancement of its fluorescent intensity when exposed to H2S or cysteine molecules. Indeed this new metal-organic framework (MOF) structure shows high selectivity of biothiols over other amino acids and exhibits favorable stability. Moreover, in vitro viability assays on HeLa cells show low cytotoxicity of MN-ZIF-90 and its imaging contrast efficiency is further demonstrated by fluorescence microscopy studies. This facile yet powerful strategy also offers great potential of using open-framework materials (i.e. MOFs) as the novel platform for sensing and other biological applications.

  4. Syntheses, structures, molecular and cationic recognitions and catalytic properties of two lanthanide coordination polymers based on a flexible tricarboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yu; Wang, Yan-Mei; Xu, Ji; Liu, Pan; Weththasinha, H.A.B.M.D.; Wu, Yun-Long; Lu, Xiao-Qing; Xie, Ji-Min, E-mail: xiejm391@sohu.com

    2014-11-15

    Two lanthanide coordination polymers, namely, ([La(TTTA)(H{sub 2}O){sub 2}]·2H{sub 2}O){sub n} (La-TTTA) and [Nd(TTTA)(H{sub 2}O){sub 2}]·2H{sub 2}O){sub n} (Nd-TTTA) have been hydrothermally synthesized through the reaction of lanthanide ions (La{sup 3+} and Nd{sup 3+}) with the flexible tripodal ligand 2,2′,2″-[1,3,5-triazine-2,4,6-triyltris(thio)]tris-acetic acid (H{sub 3}TTTA). La-TTTA and Nd-TTTA are isostructural and both show three dimensional structures. La-TTTA and Nd-TTTA show good recognition of amine molecules via quenching the luminescent intensities in amines emulsions. They can also recognize Fe{sup 3+}, Cu{sup 2+}, Mg{sup 2+}, Cr{sup 3+} and Co{sup 2+} ions with the quenching the peak around 361 nm when the compounds immersed in ionic solutions. The two compounds act as efficient Lewis acid catalysts for the cyanosilylation of benzaldehyde and derivatives in high yields shortly due to the strong Lewis acidity and the possible open sites of the lanthanide ions. - Graphical abstract: We have synthesized two isostructural 3D compounds based on H{sub 3}TTTA. They are chemical sensor of amine solvents and cations. They have higher yields and TOFs to catalyze cyanosilylation reactions. - Highlights: • The compounds show recognition of amine molecules via quenching luminescent intensities. • The compounds recognize Fe{sup 3+}, Cu{sup 2+}, Mg{sup 2+}, Cr{sup 3+} and Co{sup 2+} ions via quenching the peak around 361 nm. • They act as efficient Lewis acid catalysts for the cyanosilylation reactions in high yields.

  5. Combining an Elastic Network With a Coarse-Grained Molecular Force Field : Structure, Dynamics, and Intermolecular Recognition

    NARCIS (Netherlands)

    Periole, Xavier; Cavalli, Marco; Marrink, Siewert-Jan; Ceruso, Marco A.

    Structure-based and physics-based coarse-grained molecular force fields have become attractive approaches to gain mechanistic insight into the function of large biomolecular assemblies. Here, we study how both approaches can be combined into a single representation, that we term ELNEDIN. In this

  6. Proceedings of the Twenty-Third Annual Symposium of the Pattern Recognition Association of South Africa, 29-30 November 2012 Pretoria, South Africa

    CSIR Research Space (South Africa)

    De Waal, A

    2012-11-01

    Full Text Available -30 November 2012 Pretoria, South Africa Hosted by: Council for Scientific and Industrial Research (CSIR) http://www.prasa.org Edited by: Alta de Waal ISBN 978-0-620-54601-0 Publication date: 29 November 2012 Member of the International Association... of Pattern Recognition (IAPR) iii Organisation PRASA 2012 was organised by the Council for Scientific and Industrial Research (CSIR). Organising Committee Alta de Waal Asheer Bachoo Jason de Villiers Natasha Govender iv Review process Full...

  7. An effective HIV-1 integrase inhibitor screening platform: Rationality validation of drug screening, conformational mobility and molecular recognition analysis for PFV integrase complex with viral DNA.

    Science.gov (United States)

    Du, Wenyi; Zuo, Ke; Sun, Xin; Liu, Wei; Yan, Xiao; Liang, Li; Wan, Hua; Chen, Fengzheng; Hu, Jianping

    2017-11-01

    As an important target for the development of novel anti-AIDS drugs, HIV-1 integrase (IN) has been widely concerned. However, the lack of a complete accurate crystal structure of HIV-1 IN greatly blocks the discovery of novel inhibitors. In this work, an effective HIV-1 IN inhibitor screening platform, namely PFV IN, was filtered from all species of INs. Next, the 40.8% similarity with HIV-1 IN, as well as the high efficiency of virtual screening and the good agreement between calculated binding free energies and experimental ones all proved PFV IN is a promising screening platform for HIV-1 IN inhibitors. Then, the molecular recognition mechanism of PFV IN by its substrate viral DNA and six naphthyridine derivatives (NRDs) inhibitors was investigated through molecular docking, molecular dynamics simulations and water-mediated interactions analyses. The functional partition of NRDs IN inhibitors could be divided into hydrophobic and hydrophilic ones, and the Mg 2+ ions, water molecules and conserved DDE motif residues all interacted with the hydrophilic partition, while the bases in viral DNA and residues like Tyr212, Pro214 interacted with the hydrophobic one. Finally, the free energy landscape (FEL) and cluster analyses were performed to explore the molecular motion of PFV IN-DNA system. It is found that the association with NRDs inhibitors would obviously decrease the motion amplitude of PFV IN-DNA, which may be one of the most potential mechanisms of IN inhibitors. This work will provide a theoretical basis for the inhibitor design based on the structure of HIV-1 IN. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography.

    Science.gov (United States)

    Thompson, Larry H

    2012-01-01

    The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Towards a molecular interpretation of astringency: synthesis, 3D structure, colloidal state, and human saliva protein recognition of procyanidins.

    Science.gov (United States)

    Cala, Olivier; Fabre, Sandy; Pinaud, Noël; Dufourc, Erick J; Fouquet, Eric; Laguerre, Michel; Pianet, Isabelle

    2011-07-01

    Astringency is a sensation in the mouth used in judging the quality of red wine. The rough, dry, and puckering sensation called astringency is the result of an interaction between tannins and saliva proteins, mainly proline-rich proteins (PRP), which leads to the formation and precipitation of a complex. A dry and rough sensation is then perceived in the mouth. To get an insight into astringency at the molecular level we investigated: (i) An efficient and iterative method for 4-8 procyanidin synthesis, which gives rise to all possible 4-8 procyanidins up to the tetramer with total control of degree of oligomerization and stereochemistry. (ii) The 3D-structural preferences, which take into account their internal movements, using 2D NMR and molecular modeling. (iii) The self-association process in water or hydroalcoholic solutions using diffusion NMR spectroscopy that gives the active proportion of tannins able to fix proteins. (iv) A comprehensive description of the PRP-procyanidin complex formation to get information about stoichiometry, binding site localization, and affinity constants for different procyanidins. The data collected suggest that the interactions are controlled by both procyanidin conformational and colloidal state preferences. All these results provide new insights into the molecular interpretation of tannin astringency. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Molecularly imprinted electrochemical sensing interface based on in-situ-polymerization of amino-functionalized ionic liquid for specific recognition of bovine serum albumin.

    Science.gov (United States)

    Wang, Yanying; Han, Miao; Liu, Guishen; Hou, Xiaodong; Huang, Yina; Wu, Kangbing; Li, Chunya

    2015-12-15

    A molecularly imprinted polymer film was in situ polymerized on a carboxyl functionalized multi-walled carbon nanotubes modified glassy carbon electrode surface under room temperature. This technique provides a promising imprinting approach for protein in an aqueous solution using 3-(3-aminopropyl)-1-vinylimidazolium tetrafluoroborate ionic liquid as functional monomer, N, N'-methylenebisacrylamide as crossing linker, ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator, and bovine serum albumin (BSA) as template. The molecularly imprinted polymerized ionic liquid film shows enhanced accessibility, high specificity and sensitivity towards BSA. Electrochemical sensing performance of the imprinted sensor was thoroughly investigated using K3Fe[CN]6/K4Fe[CN]6 as electroactive probes. Under optimal conditions, the current difference before and after specific recognition of BSA was found linearly related to its concentration in the range from 1.50×10(-9) to 1.50×10(-6) mol L(-1). The detection limit was calculated to be 3.91×10(-10) mol L(-1) (S/N=3). The practical application of the imprinted sensor was demonstrated by determining BSA in liquid milk samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. CARMA2sh and ULK2 control pathogen-associated molecular patterns recognition in human keratinocytes: psoriasis-linked CARMA2sh mutants escape ULK2 censorship.

    Science.gov (United States)

    Scudiero, Ivan; Mazzone, Pellegrino; D'Andrea, Luca E; Ferravante, Angela; Zotti, Tiziana; Telesio, Gianluca; De Rubis, Gabriele; Reale, Carla; Pizzulo, Maddalena; Muralitharan, Shanmugakonar; Vito, Pasquale; Stilo, Romania

    2017-02-23

    The molecular complexes formed by specific members of the family of CARMA proteins, the CARD domain-containing adapter molecule BCL10 and MALT1 (CBM complex) represent a central hub in regulating activation of the pleiotropic transcription factor NF-κB. Recently, missense mutations in CARMA2sh have been shown to cause psoriasis in a dominant manner and with high penetrancy. Here, we demonstrate that in human keratinocytes CARMA2sh plays an essential role in the signal transduction pathway that connects pathogen-associated molecular patterns recognition to NF-κB activation. We also find that the serine/threonine kinase ULK2 binds to and phosphorylates CARMA2sh, thereby inhibiting its capacity to activate NF-κB by promoting lysosomal degradation of BCL10, which is essential for CARMA2sh-mediated NF-κB signaling. Remarkably, CARMA2sh mutants associated with psoriasis escape ULK2 inhibition. Finally, we show that a peptide blocking CARD-mediated BCL10 interactions reduces the capacity of psoriasis-linked CARMA2sh mutants to activate NF-κB. Our work elucidates a fundamental signaling mechanism operating in human keratinocytes and opens to novel potential tools for the therapeutical treatment of human skin disorders.

  12. DNA aptamer functionalized gold nanostructures for molecular recognition and photothermal inactivation of methicillin-Resistant Staphylococcus aureus.

    Science.gov (United States)

    Ocsoy, Ismail; Yusufbeyoglu, Sadi; Yılmaz, Vedat; McLamore, Eric S; Ildız, Nilay; Ülgen, Ahmet

    2017-11-01

    In this work, we report the development of DNA aptamer-functionalized gold nanoparticles (Apt@Au NPs) and gold nanorods (Apt@Au NRs) for inactivation of Methicillin-resistant Staphylococcus aureus (MRSA) with targeted photothermal therapy (PTT). Although both Apt@Au NPs and Apt@Au NRs specifically bind to MRSA cells, Apt@Au NPs and Apt@Au NRs inactivated ∼5% and over 95% of the cells,respectively through PTT. This difference in inactivation was based on the relatively high longitudinal absorption of near-infrared (NIR) radiation and strong photothermal conversion capability for the Apt@Au NRs compared to the Apt@Au NPs. The Au NRs served as a nanoplatform for the loading of thiolated aptamer and also provided multivalent effects for increasing binding strength and affinity to MRSA. Our results indicate that the type of aptamer and the degree of multivalent effect(s) are important factors for MRSA inactivation efficiency in PTT. We show that the Apt@Au NRs are a very effective and promising nanosystem for specific cell recognition and in vitro PTT. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Recognition of RNA by amide modified backbone nucleic acids: molecular dynamics simulations of DNA-RNA hybrids in aqueous solution.

    Science.gov (United States)

    Nina, Mafalda; Fonné-Pfister, Raymonde; Beaudegnies, Renaud; Chekatt, Habiba; Jung, Pierre M J; Murphy-Kessabi, Fiona; De Mesmaeker, Alain; Wendeborn, Sebastian

    2005-04-27

    Thermodynamic and structural properties of a chemically modified DNA-RNA hybrid in which a phosphodiester linkage is replaced by a neutral amide-3 linkage (3'-CH(2)-CONH-5') were investigated using UV melting experiments, molecular dynamics simulations in explicit water, and continuum solvent models. van't Hoff analysis of the experimental UV melting curves suggests that the significant increase of the thermodynamic stability of a 15-mer DNA-RNA with seven alternated amide-3 modifications (+11 degrees C) is mainly due to an increased binding enthalpy. To further evaluate the origin in the observed affinities differences, the electrostatic contribution to the binding free energy was calculated by solving the Poisson-Boltzmann equation numerically. The nonelectrostatic contribution was estimated as the product of a hydrophobic surface tension coefficient and the surface area that is buried upon double strand formation. Structures were taken from 10 ns molecular dynamics simulations computed in a consistent fashion using explicit solvent, counterions, and the particle-mesh Ewald procedure. The present preliminary thermodynamic study suggests that the favorable binding free energy of the amide-3 DNA single strand to the complementary RNA is equally driven by electrostatic and nonpolar contributions to the binding compared to their natural analogues. In addition, molecular dynamics simulations in explicit water were performed on an amide-3 DNA single strand and the corresponding natural DNA. Results from the conformations cluster analysis of the simulated amide-3 DNA single strand ensembles suggest that the 25% of the population sampled within 10 ns has a pre-organized conformation where the sugar C3' endo pucker is favored at the 3'-flanking nucleotides. These structural and thermodynamic features contribute to the understanding of the observed increased affinities of the amide-3 DNA-RNA hybrids at the microscopic level.

  14. Triple-negative breast cancer: the importance of molecular and histologic subtyping, and recognition of low-grade variants.

    Science.gov (United States)

    Pareja, Fresia; Geyer, Felipe C; Marchiò, Caterina; Burke, Kathleen A; Weigelt, Britta; Reis-Filho, Jorge S

    2016-01-01

    Triple-negative breast cancers (TNBCs), defined by lack of expression of estrogen receptor, progesterone receptor and HER2, account for 12-17% of breast cancers and are clinically perceived as a discrete breast cancer subgroup. Nonetheless, TNBC has been shown to constitute a vastly heterogeneous disease encompassing a wide spectrum of entities with marked genetic, transcriptional, histological and clinical differences. Although most TNBCs are high-grade tumors, there are well-characterized low-grade TNBCs that have an indolent clinical course, whose natural history, molecular features and optimal therapy vastly differ from those of high-grade TNBCs. Secretory and adenoid cystic carcinomas are two histologic types of TNBCs underpinned by specific fusion genes; these tumors have an indolent clinical behavior and lack all of the cardinal molecular features of high-grade triple-negative disease. Recent studies of rare entities, including lesions once believed to constitute mere benign breast disease (e.g., microglandular adenosis), have resulted in the identification of potential precursors of TNBC and suggested the existence of a family of low-grade triple-negative lesions that, despite having low-grade morphology and indolent clinical behavior, have been shown to harbor the complex genomic landscape of common forms of TNBC, and may progress to high-grade disease. In this review, we describe the heterogeneity of TNBC and focus on the histologic and molecular features of low-grade forms of TNBC. Germane to addressing the challenges posed by the so-called triple-negative disease is the realization that TNBC is merely a descriptive term, and that low-grade types of TNBC may be driven by distinct sets of genetic alterations.

  15. Abstracts of the 26. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology; Resumos da 26. reuniao anual da Sociedade Brasileira de Bioquimica e Biologia Molecular

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    This meeting was about biochemistry and molecular biology. It was discussed topics related to bio energetic, channels, transports, biotechnology, metabolism, cellular biology, immunology, toxicology, photobiology and pharmacology.

  16. Abstracts of the 27. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology; Resumos da 27. reuniao anual da Sociedade Brasileira de Bioquimica e Biologia Molecular

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    This meeting was about biochemistry and molecular biology. It was discussed topics related to bio energetic, channels, transports, biotechnology, metabolism, cellular biology, immunology, toxicology, photobiology and pharmacology.

  17. Recognition/removal of phloretic acid on molecularly imprinted poly(n-vinyl imidazole) based polymers grafted onto nonwoven fabrics

    International Nuclear Information System (INIS)

    Ranada, Ma. Llorina; Abad, Lucille; Akbulut, Meshude; Guven, Olgun

    2013-01-01

    Molecular imprinting is the process of developing polymeric matrices for recognizing a target molecule in the presence of chemically similar structures. These matrices can be tailored using one or more functional monomers with a cross linker in the presence of a molecule behaving as the template. Phloretic acid is one of the members of dietary phenolic group which may have physiological antioxidant properties, potentially modifying pathological mechanisms relevant to some health problems such as cardiovascular diseases and cancer. The content of these compounds is generally very low in plants to be detected by traditional instruments. Thus, the development of an easy, cheap and reliable method is an important issue. In this study, a solution of n-vinyl imidazole was grafted onto polypropylene/polyethylene (PP/PE) films through gamma irradiation to create a film-based polymer matrix for phloretic acid. These films are assessed in terms of structural and binding capacity. The maximum free-volume ratio was obtained at 5 kGy using positron annihilation lifetime spectroscopy (PALS). The imprinting capacity of the matrix system is 2.41 between the molecularly-imprinted and the non-imprinted films. Scanning electron microscopy and Fourier-Transform Infrared Spectroscopy complemented the PALS data in elucidating the structure of the grafted films. (author)

  18. Molecularly imprinted macroporous monoliths for solid-phase extraction: Effect of pore size and column length on recognition properties.

    Science.gov (United States)

    Vlakh, E G; Stepanova, M A; Korneeva, Yu M; Tennikova, T B

    2016-09-01

    The series of macroporous monolithic molecularly imprinted monoliths differed by pore size, column length (volume) and amount of template used for imprinting was synthesized using methacrylic acid and glycerol dimethacrylate as co-monomers and antibiotic ciprofloxacin as a template. The prepared monoliths were characterized regarding to their permeability, pore size, porosity, and resistance to the flow of a mobile phase. The surface morphology was also analyzed. The slight dependence of imprinting factor on flow rate, as well as its independence on pore size of macroporous molecularly imprinted monolithic media was observed. The column obtained at different conditions exhibited different affinity of ciprofloxacin to the imprinted sites that was characterized with Kdiss values in the range of 10(-5)-10(-4)M. The solid-phase extraction of ciprofloxacin from such biological liquids as human blood serum, human urine and cow milk serum was performed using the developed monolithic columns. In all cases, the extraction was found to be 95.0-98.6%. Additionally, the comparison of extraction of three fluoroqinolone analogues, e.g. ciprofloxacin, levofloxacin and moxifloxacin, from human blood plasma was carried out. Contrary to ciprofloxacin extracted with more than 95%, this parameter did not exceed 40% for its analogues. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Galatheoidea are not monophyletic - molecular and morphological phylogeny of the squat lobsters (Decapoda: Anomura) with recognition of a new superfamily.

    Science.gov (United States)

    Schnabel, K E; Ahyong, S T; Maas, E W

    2011-02-01

    The monophyletic status of the squat lobster superfamily Galatheoidea has come under increasing doubt by studies using evidence as diverse as larval and adult somatic morphology, sperm ultrastructure, and molecular data. Here we synthesize phylogenetic data from these diverse strands, with the addition of new molecular and morphological data to examine the phylogeny of the squat lobsters and assess the status of the Galatheoidea. A total of 64 species from 16 of the 17 currently recognised anomuran families are included. Results support previous work pointing towards polyphyly in the superfamily Galatheoidea and Paguroidea, specifically, suggesting independent origins of the Galatheidae+Porcellanidae and the Chirostylidae+Kiwaidae. Morphological characters are selected that support clades resolved in the combined analysis and the taxonomic status of Galatheoidea sensu lato is revised. Results indicate that Chirostylidae are more closely related to an assemblage including Aegloidea, Lomisoidea and Paguroidea than to the remaining Galatheoidea and are referred to the superfamily Chirostyloidea to include the Chirostylidae and Kiwaidae. A considerable amount of research highlighting morphological differences supporting this split is discussed. The Galatheoidea sensu stricto is restricted to the families Galatheidae and Porcellanidae, and diagnoses for both Chirostyloidea and Galatheoidea are provided. Present results highlight the need for a detailed revision of a number of taxa, challenge some currently used morphological synapomorphies, and emphasise the need for integrated studies with wide taxon sampling and multiple data sources to resolve complex phylogenetic questions. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Molecularly Imprinted Polymer Enables High-Efficiency Recognition and Trapping Lithium Polysulfides for Stable Lithium Sulfur Battery.

    Science.gov (United States)

    Liu, Jie; Qian, Tao; Wang, Mengfan; Liu, Xuejun; Xu, Na; You, Yizhou; Yan, Chenglin

    2017-08-09

    Using molecularly imprinted polymer to recognize various target molecules emerges as a fascinating research field. Herein, we applied this strategy for the first time to efficiently recognize and trap long-chain polysulfides (Li 2 S x , x = 6-8) in lithium sulfur battery to minimize the polysulfide shuttling between anode and cathode, which enables us to achieve remarkable electrochemical performance including a high specific capacity of 1262 mAh g -1 at 0.2 C and superior capacity retention of over 82.5% after 400 cycles at 1 C. The outstanding performance is attributed to the significantly reduced concentration of long-chain polysulfides in electrolyte as evidenced by in situ UV/vis spectroscopy and Li 2 S nucleation tests, which were further confirmed by density functional theory calculations. The molecular imprinting is demonstrated as a promising approach to effectively prevent the free diffusion of long-chain polysulfides, providing a new avenue to efficiently recognize and trap lithium polysulfides for high-performance lithium sulfur battery with greatly suppressed shuttle effect.

  1. Insight into the intermolecular recognition mechanism between Keap1 and IKKβ combining homology modelling, protein-protein docking, molecular dynamics simulations and virtual alanine mutation.

    Directory of Open Access Journals (Sweden)

    Zheng-Yu Jiang

    Full Text Available Degradation of certain proteins through the ubiquitin-proteasome pathway is a common strategy taken by the key modulators responsible for stress responses. Kelch-like ECH-associated protein-1(Keap1, a substrate adaptor component of the Cullin3 (Cul3-based ubiquitin E3 ligase complex, mediates the ubiquitination of two key modulators, NF-E2-related factor 2 (Nrf2 and IκB kinase β (IKKβ, which are involved in the redox control of gene transcription. However, compared to the Keap1-Nrf2 protein-protein interaction (PPI, the intermolecular recognition mechanism of Keap1 and IKKβ has been poorly investigated. In order to explore the binding pattern between Keap1 and IKKβ, the PPI model of Keap1 and IKKβ was investigated. The structure of human IKKβ was constructed by means of the homology modeling method and using reported crystal structure of Xenopus laevis IKKβ as the template. A protein-protein docking method was applied to develop the Keap1-IKKβ complex model. After the refinement and visual analysis of docked proteins, the chosen pose was further optimized through molecular dynamics simulations. The resulting structure was utilized to conduct the virtual alanine mutation for the exploration of hot-spots significant for the intermolecular interaction. Overall, our results provided structural insights into the PPI model of Keap1-IKKβ and suggest that the substrate specificity of Keap1 depend on the interaction with the key tyrosines, namely Tyr525, Tyr574 and Tyr334. The study presented in the current project may be useful to design molecules that selectively modulate Keap1. The selective recognition mechanism of Keap1 with IKKβ or Nrf2 will be helpful to further know the crosstalk between NF-κB and Nrf2 signaling.

  2. Pattern recognition

    CERN Document Server

    Theodoridis, Sergios

    2003-01-01

    Pattern recognition is a scientific discipline that is becoming increasingly important in the age of automation and information handling and retrieval. Patter Recognition, 2e covers the entire spectrum of pattern recognition applications, from image analysis to speech recognition and communications. This book presents cutting-edge material on neural networks, - a set of linked microprocessors that can form associations and uses pattern recognition to ""learn"" -and enhances student motivation by approaching pattern recognition from the designer's point of view. A direct result of more than 10

  3. Equilibrium shift in solution: molecular shape recognition and precipitation of a synthetic double helix using helicene-grafted silica nanoparticles.

    Science.gov (United States)

    Miyagawa, Masamichi; Ichinose, Wataru; Yamaguchi, Masahiko

    2014-01-27

    Chiral silica nanoparticles (70 nm) grafted with (P)-helicene recognized the molecular shape of double helix and random coil (P)-ethynylhelicene oligomers in solution. A mixture of the (P)-nanoparticles and double helix precipitated much faster than a mixture of the (P)-nanoparticles and random coil, and the precipitate contained only the double helix. The mixture of the (P)-nanoparticles and (P)-ethynylhelicene pentamer reversibly dispersed in trifluoromethylbenzene upon heating at 70 °C and precipitated upon cooling at 25 °C. When a 10:90 equilibrium mixture of the double helix and random coil in solution was treated with the (P)-nanoparticles, the double helix was precipitated in 53% yield and was accompanied by equilibrium shift. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Radiation synthesis of carboxymethyl cellulose hydrogel imprinted with β-estradiol for molecular recognition of endocrine disruptive chemicals

    International Nuclear Information System (INIS)

    Dela Cruz, Rafael Miguel M.; Estorque, Kit Joshua J.

    2015-03-01

    This study demonstrates the possibility of synthesizing molecularly imprinted polymers (MIP) using carboxymethyl cellulose in low concentration and pH, and intiated by γ-irradiation. The capability of the synthesized MIPs to absorb specific molecules was demonstrated using an NIP which adsorbing capability was successfully done. The selectivity of molecules is beyond the scope of this study. Right amount of monomer and solvents affects the capability of the imprinted polymer to be formed. It was also found out that it is important to acidify the CMC mixture to enable the cross-linking of CMC chains without using a cross-linker. It was confirmed that β-estradiol is soluble in acentonitrile by subjecting the mixture to UV-Vis spectrophotometry. The Incorporation of β-estradiol to CMC after γ-irradiation was also confirmed using FTIR-ATR. (author)

  5. 55th Annual Canadian Society for Molecular Biosciences Conference on Epigenetics and Genomic Stability. Whistler, British Columbia, Canada, 14–18 March 2012.

    Science.gov (United States)

    Nelson, Christopher J; Ausió, Juan

    2012-06-01

    The 55th Annual Canadian Society for Molecular Biosciences Conference on Epigenetics and Genomic Stability in Whistler, Canada, 14-18 March 2012, brought together 31 speakers from different nationalities. The organizing committee, led by Jim Davie (Chair) at the University of Manitoba (Manitoba, Canada), consisted of several established researchers in the fields of chromatin and epigenetics from across Canada. The meeting was centered on the contribution of epigenetics to gene expression, DNA damage and repair, and the role of environmental factors. A few interesting talks on replication added some insightful information on the controversial issue of histone post-translational modifications as genuine epigenetic marks that are inherited through cell division.

  6. High-capacity hollow porous dummy molecular imprinted polymers using ionic liquid as functional monomer for selective recognition of salicylic acid.

    Science.gov (United States)

    Xiang, Haiyan; Peng, Mijun; Li, Hui; Peng, Sheng; Shi, Shuyun

    2017-01-30

    The existence of strong intramolecular hydrogen bond in salicylic acid (SA) weakens its intermolecular hydrogen bonding with functional monomer, then it is a challenge work to fabricate molecularly imprinted polymers (MIPs) for SA recognition with high capacity and good selectivity. Here, hollow porous dummy MIPs (HPDMIPs) were prepared using benzoic acid (BA) as dummy template, ionic liquid (i.e. 1-vinyl-3-methylimidazolium chloride) as functional monomer, and MCM-48 as sacrificial support. Factors that affected adsorption, such as type of template and porogen, mole ratio of template-functional monomer-cross-linker and type of binding solvent, were optimized in detail. Multiple strong interactions between SA and ionic liquid in HPDMIPs deduced higher binding capacity (29.75mg/g), imprinting factor (5.61) and selectivity than any previously reported MIPs by traditional or surface imprinting technology. The large surface area (543.9m 2 /g) with hollow porous structure resulted in faster kinetic binding (25min). The equilibrium data fitted well to Freundlich equation and the adsorption process could be described by pseudo-second order model. Finally, HPDMIPs were successfully applied to selectively extract and enrich SA from Actinidia chinensis with a relatively high recovery (84.6-94.5%). Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Role of DNA conformation & energetic insights in Msx-1-DNA recognition as revealed by molecular dynamics studies on specific and nonspecific complexes.

    Science.gov (United States)

    Kachhap, Sangita; Singh, Balvinder

    2015-01-01

    In most of homeodomain-DNA complexes, glutamine or lysine is present at 50th position and interacts with 5th and 6th nucleotide of core recognition region. Molecular dynamics simulations of Msx-1-DNA complex (Q50-TG) and its variant complexes, that is specific (Q50K-CC), nonspecific (Q50-CC) having mutation in DNA and (Q50K-TG) in protein, have been carried out. Analysis of protein-DNA interactions and structure of DNA in specific and nonspecific complexes show that amino acid residues use sequence-dependent shape of DNA to interact. The binding free energies of all four complexes were analysed to define role of amino acid residue at 50th position in terms of binding strength considering the variation in DNA on stability of protein-DNA complexes. The order of stability of protein-DNA complexes shows that specific complexes are more stable than nonspecific ones. Decomposition analysis shows that N-terminal amino acid residues have been found to contribute maximally in binding free energy of protein-DNA complexes. Among specific protein-DNA complexes, K50 contributes more as compared to Q50 towards binding free energy in respective complexes. The sequence dependence of local conformation of DNA enables Q50/Q50K to make hydrogen bond with nucleotide(s) of DNA. The changes in amino acid sequence of protein are accommodated and stabilized around TAAT core region of DNA having variation in nucleotides.

  8. Recognition and determination of bovine hemoglobin using a gold electrode modified with gold nanoparticles and molecularly imprinted self-polymerized dopamine

    International Nuclear Information System (INIS)

    Li, Lu; Fan, Limei; Dai, Yunlong; Kan, Xianwen

    2015-01-01

    A molecularly imprinted polymer (MIP) was prepared by self-polymerization of dopamine in the presence of bovine hemoglobin (BHb) and then deposited on the surface of an electrode modified with gold nanoparticles (AuNPs). Scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry were employed to characterize the modified electrode using the hexacyanoferrate redox system as an electroactive probe. The effects of BHb concentration, dopamine concentration, and polymerization time were optimized. Under optimized conditions, the modified electrode selectively recognizes BHb even in the presence of other proteins. The peak current for hexacyanoferrate, typically measured at + 0.17 V (vs. SCE), depends on the concentration of BHb in the 1.0 × 10 −11 to 1.0 × 10 −2 mg mL −1 range. Due to the ease of preparation and tight adherence of polydopamine to various support materials, the present strategy conceivably also provides a platform for the recognition and detection of other proteins. (author)

  9. In Vitro Selection of Single-Stranded DNA Molecular Recognition Elements against S. aureus Alpha Toxin and Sensitive Detection in Human Serum

    Directory of Open Access Journals (Sweden)

    Ka L. Hong

    2015-01-01

    Full Text Available Alpha toxin is one of the major virulence factors secreted by Staphylococcus aureus, a bacterium that is responsible for a wide variety of infections in both community and hospital settings. Due to the prevalence of S. aureus related infections and the emergence of methicillin-resistant S. aureus, rapid and accurate diagnosis of S. aureus infections is crucial in benefiting patient health outcomes. In this study, a rigorous Systematic Evolution of Ligands by Exponential Enrichment (SELEX variant previously developed by our laboratory was utilized to select a single-stranded DNA molecular recognition element (MRE targeting alpha toxin with high affinity and specificity. At the end of the 12-round selection, the selected MRE had an equilibrium dissociation constant (Kd of 93.7 ± 7.0 nM. Additionally, a modified sandwich enzyme-linked immunosorbent assay (ELISA was developed by using the selected ssDNA MRE as the toxin-capturing element and a sensitive detection of 200 nM alpha toxin in undiluted human serum samples was achieved.

  10. Molecular basis of IgE-recognition of Lol p 5, a major allergen of rye-grass pollen.

    Science.gov (United States)

    Suphioglu, C; Blaher, B; Rolland, J M; McCluskey, J; Schäppi, G; Kenrick, J; Singh, M B; Knox, R B

    1998-04-01

    Grass pollen, especially of rye-grass (Lolium perenne). represents an important cause of type I allergy. Identification of IgE-binding (allergenic) epitopes of major grass pollen allergens is essential for understanding the molecular basis of interaction between allergens and human IgE antibodies and therefore facilitates the devising of safer and more effective diagnostic and immunotherapy reagents. The aim of this study was to identify the allergenic epitopes of Lol p 5, a major allergen of rye-grass pollen, immunodissect these epitopes further so that the amino acid residues critical for antibody binding can be determined and investigate the conservation and nature of these epitopes within the context of the natural grass pollen allergens. Peptides, 12-13 amino acid residues long and overlapping each other by 4 amino acid residues, based on the entire deduced amino acid sequence of the coding region of Lol p 5, were synthesised and assayed for IgE-binding. Two strong IgE-binding epitopes (Lol p 5 (49-60) and (265-276), referred to as peptides 7 and 34, respectively) were identified. These epitopes were further resolved by truncated peptides and amino acid replacement studies and the amino acid residues critical for IgE-binding determined (Lol p 5 (49-60) residue Lys57 and (265-276) residue Lys275). Sequences of these epitopes were conserved in related allergens and may form the conserved allergenic domains responsible for the cross-reactivity observed between pollen allergens of taxonomically related grasses. Furthermore, due to its strong IgE-reactivity, synthetic peptide Lol p 5 (265-276) was used to affinity-purify specific IgE antibodies which recognised proteins of other clinically important grass pollens. further indicating presence of allergenic cross-reactivity at the level of allergenic epitope. Moreover, Lol p 5 (265 276) demonstrated a strong capacity to inhibit IgE-binding to natural rye-grass pollen proteins highlighting the antibody accessibility

  11. Program and abstracts of the 25. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology

    International Nuclear Information System (INIS)

    1996-01-01

    The meeting was about biochemistry and molecular biology.In this meeting it was also discussed the following subjects: biotechnology, metabolism, enzymes, proteins, immunology, drugs and others related topics

  12. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol–gel surface imprinting technology

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni, E-mail: tannii@21cn.com

    2016-02-28

    Graphical abstract: - Highlights: • Nordihydroguaiaretic acid imprinted polymer with imprinting factor 2.12 was prepared for the first time through hydrogen bonding and hydrophobic interaction between the template molecules and the bifunctional monomers. • The obtained surface molecularly imprinting polymers exhibited high affinity and selectivity to the template molecules. • The prepared surface molecularly imprinted polymers were used in separation the natural active component nordihydroguaiaretic acid from medicinal plants. - Abstract: In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO{sub 2}) was prepared through sol–gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO{sub 2}) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO{sub 2} and NIP@SiO{sub 2} were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO{sub 2} could reach to 5.90 mg g{sup −1}, which was two times more than that of NIP@SiO{sub 2}. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results

  13. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol–gel surface imprinting technology

    International Nuclear Information System (INIS)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni

    2016-01-01

    Graphical abstract: - Highlights: • Nordihydroguaiaretic acid imprinted polymer with imprinting factor 2.12 was prepared for the first time through hydrogen bonding and hydrophobic interaction between the template molecules and the bifunctional monomers. • The obtained surface molecularly imprinting polymers exhibited high affinity and selectivity to the template molecules. • The prepared surface molecularly imprinted polymers were used in separation the natural active component nordihydroguaiaretic acid from medicinal plants. - Abstract: In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO_2) was prepared through sol–gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO_2) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO_2 and NIP@SiO_2 were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO_2 could reach to 5.90 mg g"−"1, which was two times more than that of NIP@SiO_2. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results indicated that the MIP@SiO_2 had

  14. Role of protein structure and the role of individual fingers in zinc finger protein-DNA recognition: a molecular dynamics simulation study and free energy calculations

    Science.gov (United States)

    Hamed, Mazen Y.

    2018-05-01

    Molecular dynamics and MM_GBSA energy calculations on various zinc finger proteins containing three and four fingers bound to their target DNA gave insights into the role of each finger in the DNA binding process as part of the protein structure. The wild type Zif 268 (PDB code: 1AAY) gave a ΔG value of - 76.1 (14) kcal/mol. Zinc fingers ZF1, ZF2 and ZF3 were mutated in one experiment and in another experiment one finger was cut and the rest of the protein was studied for binding. The ΔΔG values for the Zinc Finger protein with both ZF1 and ZF2 mutated was + 80 kcal/mol, while mutating only ZF1 the ΔΔG value was + 52 kcal/mol (relative to the wild type). Cutting ZF3 and studying the protein consisting only of ZF1 linked to ZF2 gave a ΔΔG value of + 68 kcal/mol. Upon cutting ZF1, the resulting ZF2 linked to ZF3 protein gave a ΔΔG value of + 41 kcal/mol. The above results shed light on the importance of each finger in the binding process, especially the role of ZF1 as the anchoring finger followed in importance by ZF2 and ZF3. The energy difference between the binding of the wild type protein Zif268 (1AAY) and that for individual finger binding to DNA according to the formula: ΔΔGlinkers, otherstructuralfactors = ΔGzif268 - (ΔGF1+F2+F3) gave a value = - 44.5 kcal/mol. This stabilization can be attributed to the contribution of linkers and other structural factors in the intact protein in the DNA binding process. DNA binding energies of variant proteins of the wild type Zif268 which differ in their ZF1 amino acid sequence gave evidence of a good relationship between binding energy and recognition and specificity, this finding confirms the reported vital role of ZF1 in the ZF protein scanning and anchoring to the target DNA sequence. The role of hydrogen bonds in both specific and nonspecific amino acid-DNA contacts is discussed in relation to mutations. The binding energies of variant Zinc Finger proteins confirmed the role of ZF1 in the recognition

  15. Speech Recognition

    Directory of Open Access Journals (Sweden)

    Adrian Morariu

    2009-01-01

    Full Text Available This paper presents a method of speech recognition by pattern recognition techniques. Learning consists in determining the unique characteristics of a word (cepstral coefficients by eliminating those characteristics that are different from one word to another. For learning and recognition, the system will build a dictionary of words by determining the characteristics of each word to be used in the recognition. Determining the characteristics of an audio signal consists in the following steps: noise removal, sampling it, applying Hamming window, switching to frequency domain through Fourier transform, calculating the magnitude spectrum, filtering data, determining cepstral coefficients.

  16. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol-gel surface imprinting technology

    Science.gov (United States)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni

    2016-02-01

    In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO2) was prepared through sol-gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO2) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO2 and NIP@SiO2 were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO2 could reach to 5.90 mg g-1, which was two times more than that of NIP@SiO2. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results indicated that the MIP@SiO2 had potential application in separation of the natural active component NDGA from medicinal plants.

  17. Inherent dynamics of head domain correlates with ATP-recognition of P2X4 receptors: insights gained from molecular simulations.

    Directory of Open Access Journals (Sweden)

    Li-Dong Huang

    Full Text Available P2X receptors are ATP-gated ion channels involved in many physiological functions, and determination of ATP-recognition (AR of P2X receptors will promote the development of new therapeutic agents for pain, inflammation, bladder dysfunction and osteoporosis. Recent crystal structures of the zebrafish P2X4 (zfP2X4 receptor reveal a large ATP-binding pocket (ABP located at the subunit interface of zfP2X4 receptors, which is occupied by a conspicuous cluster of basic residues to recognize triphosphate moiety of ATP. Using the engineered affinity labeling and molecular modeling, at least three sites (S1, S2 and S3 within ABP have been identified that are able to recognize the adenine ring of ATP, implying the existence of at least three distinct AR modes in ABP. The open crystal structure of zfP2X4 confirms one of three AR modes (named AR1, in which the adenine ring of ATP is buried into site S1 while the triphosphate moiety interacts with clustered basic residues. Why architecture of ABP favors AR1 not the other two AR modes still remains unexplored. Here, we examine the potential role of inherent dynamics of head domain, a domain involved in ABP formation, in AR determinant of P2X4 receptors. In silico docking and binding free energy calculation revealed comparable characters of three distinct AR modes. Inherent dynamics of head domain, especially the downward motion favors the preference of ABP for AR1 rather than AR2 and AR3. Along with the downward motion of head domain, the closing movement of loop139-146 and loop169-183, and structural rearrangements of K70, K72, R298 and R143 enabled ABP to discriminate AR1 from other AR modes. Our observations suggest the essential role of head domain dynamics in determining AR of P2X4 receptors, allowing evaluation of new strategies aimed at developing specific blockers/allosteric modulators by preventing the dynamics of head domain associated with both AR and channel activation of P2X4 receptors.

  18. Energy-related atomic and molecular structure and scattering studies. Annual progress report, July 1, 1980-June 30, 1981

    International Nuclear Information System (INIS)

    Bederson, B.

    1981-02-01

    The basic goals of this program concern the experimental determination of properties of atoms and molecules and molecular clusters that are important in a wide range of energy-related processes, in particular, measurements of polarizabilities of highly polar molecules and their polymers, and of a number of important atomic elements distributed through the periodic table, as well as of the scattering of low-energy electrons by these same systems. The most significant scientific accomplishment of the program during the past year has been the completion of measurements of the dc electric dipole polarizabilities of a number of alkali halide dimers [(KCl) 2 , (RbCl) 2 , (CsCl) 2 , (KF) 2 , and (CsF) 2 ]. An experiment was completed to measure the total cross sections for the scattering of low-energy electrons by atomic lithium, a very significant experimental test of a relatively simple, many-body system, which is amenable to elaborate computational determination

  19. Evolution and molecular epidemiology of classical swine fever virus during a multi-annual outbreak amongst European wild boar.

    Science.gov (United States)

    Goller, Katja V; Gabriel, Claudia; Dimna, Mireille Le; Le Potier, Marie-Frédérique; Rossi, Sophie; Staubach, Christoph; Merboth, Matthias; Beer, Martin; Blome, Sandra

    2016-03-01

    Classical swine fever is a viral disease of pigs that carries tremendous socio-economic impact. In outbreak situations, genetic typing is carried out for the purpose of molecular epidemiology in both domestic pigs and wild boar. These analyses are usually based on harmonized partial sequences. However, for high-resolution analyses towards the understanding of genetic variability and virus evolution, full-genome sequences are more appropriate. In this study, a unique set of representative virus strains was investigated that was collected during an outbreak in French free-ranging wild boar in the Vosges-du-Nord mountains between 2003 and 2007. Comparative sequence and evolutionary analyses of the nearly full-length sequences showed only slow evolution of classical swine fever virus strains over the years and no impact of vaccination on mutation rates. However, substitution rates varied amongst protein genes; furthermore, a spatial and temporal pattern could be observed whereby two separate clusters were formed that coincided with physical barriers.

  20. Speaker Recognition

    DEFF Research Database (Denmark)

    Mølgaard, Lasse Lohilahti; Jørgensen, Kasper Winther

    2005-01-01

    Speaker recognition is basically divided into speaker identification and speaker verification. Verification is the task of automatically determining if a person really is the person he or she claims to be. This technology can be used as a biometric feature for verifying the identity of a person...

  1. Evolution of Soybean mosaic virus-G7 molecularly cloned genome in Rsv1-genotype soybean results in emergence of a mutant capable of evading Rsv1-mediated recognition

    International Nuclear Information System (INIS)

    Hajimorad, M.R.; Eggenberger, A.L.; Hill, J.H.

    2003-01-01

    Plant resistance (R) genes direct recognition of pathogens harboring matching avirluent signals leading to activation of defense responses. It has long been hypothesized that under selection pressure the infidelity of RNA virus replication together with large population size and short generation times results in emergence of mutants capable of evading R-mediated recognition. In this study, the Rsv1/Soybean mosaic virus (SMV) pathosystem was used to investigate this hypothesis. In soybean line PI 96983 (Rsv1), the progeny of molecularly cloned SMV strain G7 (pSMV-G7) provokes a lethal systemic hypersensitive response (LSHR) with up regulation of a defense-associated gene transcript (PR-1). Serial passages of a large population of the progeny in PI 96983 resulted in emergence of a mutant population (vSMV-G7d), incapable of provoking either Rsv1-mediated LSHR or PR-1 protein gene transcript up regulation. An infectious clone of the mutant (pSMV-G7d) was synthesized whose sequences were very similar but not identical to the vSMV-G7d population; however, it displayed a similar phenotype. The genome of pSMV-G7d differs from parental pSMV-G7 by 17 substitutions, of which 10 are translationally silent. The seven amino acid substitutions in deduced sequences of pSMV-G7d differ from that of pSMV-G7 by one each in P1 proteinase, helper component-proteinase, and coat protein, respectively, and by four in P3. To the best of our knowledge, this is the first demonstration in which experimental evolution of a molecularly cloned plant RNA virus resulted in emergence of a mutant capable of evading an R-mediated recognition

  2. Interrogating the Molecular Basis for Substrate Recognition in Serotonin and Dopamine Transporters with High-Affinity Substrate-Based Bivalent Ligands

    DEFF Research Database (Denmark)

    Andersen, Jacob; Ladefoged, Lucy Kate; Kristensen, Trine N. Bjerre

    2016-01-01

    insight into substrate recognition in SERT and DAT. An optimized bivalent ligand comprising two serotonin moieties binds SERT with 3,800-fold increased affinity compared to that of serotonin, suggesting that the human transporters have two distinct substrate binding sites. We show that the bivalent...... ligands are inhibitors of SERT and an experimentally validated docking model suggests that the bivalent compounds bind with one substrate moiety in the central binding site (the S1 site), whereas the other substrate moiety binds in a distinct binding site (the S2 site). A systematic study of nonconserved...

  3. Surface molecular imprinting onto fluorescein-coated magnetic nanoparticlesvia reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals

    Science.gov (United States)

    Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

    2011-01-01

    In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads viareversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17β-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic

  4. A 9-vinyladenine-based molecularly imprinted polymeric membrane for the efficient recognition of plant hormone 1H-indole-3-acetic acid

    International Nuclear Information System (INIS)

    Chen Changbao; Chen Yanjun; Zhou Jie; Wu Chunhui

    2006-01-01

    9-Vinyladenine was synthesized as a novel functional monomer for molecular imprinting techniques and its structure was established with elemental analysis and 1 H NMR spectroscopy. The binding mechanism between this functional monomer 9-vinyladenine and the plant hormone 1 H-indole-3-acetic acid in acetonitrile was studied with UV-vis spectrophotometry. Based on this study, using 1 H-indole-3-acetic acid as a template molecule, a specific 9-vinyladenine-based molecularly imprinted polymeric membrane was prepared. Then, the resultant polymeric membrane morphologies were visualized with scanning electron microscopy, and the membrane permselectivity for 1 H-indole-3-acetic acid, 1 H-indole-3-butyric acid and kinetin was tested with separate experiments and competitive diffusion experiments. These results showed that the imprinted polymeric membrane prepared with 9-vinyladenine exhibited higher transport selectivity for the template molecule 1 H-indole-3-acetic acid than 1 H-indole-3-butyric acid or kinetin. The membrane prepared with 9-vinyladenine also took on higher permselectivity for 1 H-indole-3-acetic acid in comparison with the imprinted membrane made with methacrylic acid. It is predicted that the 9-vinyladenine-based molecularly imprinted membrane may be applicable to the assay of 1 H-indole-3-acetic acid or for the preparation of a molecularly imprinted polymer sensor for the analysis of 1 H-indole-3-acetic acid in plant samples

  5. HASYLAB annual report 1987

    International Nuclear Information System (INIS)

    1988-01-01

    This annual report contains extended abstracts about the work performed at HASYLAB together with a list of publications, speeches, and theses. The work concerns technical developments, the study of the electronic structure of atoms, molecules, solids, surfaces, and liquids, X-ray structure studies of solids and interfaces, molecular biology, further applications of synchrotron radiation, and experimental developments. (HSI)

  6. Recognition tunneling

    Czech Academy of Sciences Publication Activity Database

    Lindsay, S.; He, J.; Sankey, O.; Hapala, Prokop; Jelínek, Pavel; Zhang, P.; Chang, S.; Huang, S.

    2010-01-01

    Roč. 21, č. 26 (2010), 262001/1-262001/12 ISSN 0957-4484 R&D Projects: GA ČR GA202/09/0545 Institutional research plan: CEZ:AV0Z10100521 Keywords : STM * tunneling current * molecular electronics * DFT calculations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.644, year: 2010

  7. Eighteenth annual West Coast theoretical chemistry conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    Abstracts are presented from the eighteenth annual west coast theoretical chemistry conference. Topics include molecular simulations; quasiclassical simulations of reactions; photodissociation reactions; molecular dynamics;interface studies; electronic structure; and semiclassical methods of reactive systems.

  8. Molecular Recognition of Human Papilloma Virus (HPV Using Proprietary PCR Method Based on L1 Gene and the Evaluation of its Frequency in Tissue Samples from Patients with Cervical Cancer

    Directory of Open Access Journals (Sweden)

    Roohollah Dorostkar

    2015-06-01

    Full Text Available Abstract Background: In 1970, human papillomavirus (HPV was introduced as the main etiologic factor of cervical carcinoma. Since there is no possibility of detecting the virus and its subtypes using serological methods and cell culture, the molecular methods such as PCR have particular importance in accurate, early and definite diagnosis of the virus. So, in this research, our goal is to use a proprietary PCR assay based on L1 gene of human papillomavirus for molecular recognition of HPV and to evaluate its prevalence in patient samples. Materials and Methods: In this experimental study, after collecting of samples from malignant cervical lesions, the viral DNA was extracted from paraffin blocks of 50 clinical samples and PCR was done by specific primers for L1 gene of human papillomavirus in all samples. After the analysis of PCR products by 2% agarose gel electrophoresis, sensitivity and specificity of the test were also evaluated. Results: Among 50 patient samples, 33 cases were confirmed to be positive for HPV infection and 17 cases were negative, showing high frequency of HPV in this patient population (about 66%. The results of specificity assay were positive for papilloma samples and sensitivity of the assay was 20 copies of recombinant construct containing L1 per reaction. Conclusion: This study showed that PCR by specific primers for L1 gene of human papilloma virus is a proper and accurate method for detection of this virus and the results confirm the previous reports of correlation between HPV and cervical carcinoma.

  9. Chiral recognition of proteins having L-histidine residues on the surface with lanthanide ion complex incorporated-molecularly imprinted fluorescent nanoparticles

    International Nuclear Information System (INIS)

    Uzun, Lokman; Uzek, Recep; Şenel, Serap; Say, Ridvan; Denizli, Adil

    2013-01-01

    In this study, lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles were synthesized. A combination of three novel approaches was applied for the purpose. First, lanthanide ions [Terbium(III)] were complexed with N-methacryloyl-L-histidine (MAH), polymerizable derivative of L-histidine amino acid, in order to incorporate the complex directly into the polymeric backbone. At the second stage, L-histidine molecules imprinted nanoparticles were utilized instead of whole protein imprinting in order to avoid whole drawbacks such as fragility, complexity, denaturation tendency, and conformation dependency. At the third stage following the first two steps mentioned above, imprinted L-histidine was coordinated with cupric ions [Cu(II)] to conduct the study under mild conditions. Then, molecularly imprinted fluorescent nanoparticles synthesized were used for L-histidine adsorption from aqueous solution to optimize conditions for adsorption and fluorimetric detection. Finally, usability of nanoparticles was investigated for chiral biorecognition using stereoisomer, D-histidine, racemic mixture, D,L-histidine, proteins with surface L-histidine residue, lysozyme, cytochrome C, or without ribonuclease A. The results revealed that the proposed polymerization strategy could make significant contribution to the solution of chronic problems of fluorescent component introduction into polymers. Additionally, the fluorescent nanoparticles reported here could be used for selective separation and fluorescent monitoring purposes. Highlights: • Lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles • Direct incorporation of the fluorescent complex into polymeric backbone. • Imprinting by assistance of cupric ion coordination into nanoparticles • Evaluation of the chiral biorecognition ability of nanoparticles • Simultaneous selective separation and fluorescent monitoring

  10. Chiral recognition of proteins having L-histidine residues on the surface with lanthanide ion complex incorporated-molecularly imprinted fluorescent nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Uzun, Lokman, E-mail: lokman@hacettepe.edu.tr [Hacettepe University, Department of Chemistry, 06381, Ankara (Turkey); Uzek, Recep; Şenel, Serap [Hacettepe University, Department of Chemistry, 06381, Ankara (Turkey); Say, Ridvan [Anadolu University, Department of Chemistry, 26470, Eskisehir (Turkey); Denizli, Adil [Hacettepe University, Department of Chemistry, 06381, Ankara (Turkey)

    2013-08-01

    In this study, lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles were synthesized. A combination of three novel approaches was applied for the purpose. First, lanthanide ions [Terbium(III)] were complexed with N-methacryloyl-L-histidine (MAH), polymerizable derivative of L-histidine amino acid, in order to incorporate the complex directly into the polymeric backbone. At the second stage, L-histidine molecules imprinted nanoparticles were utilized instead of whole protein imprinting in order to avoid whole drawbacks such as fragility, complexity, denaturation tendency, and conformation dependency. At the third stage following the first two steps mentioned above, imprinted L-histidine was coordinated with cupric ions [Cu(II)] to conduct the study under mild conditions. Then, molecularly imprinted fluorescent nanoparticles synthesized were used for L-histidine adsorption from aqueous solution to optimize conditions for adsorption and fluorimetric detection. Finally, usability of nanoparticles was investigated for chiral biorecognition using stereoisomer, D-histidine, racemic mixture, D,L-histidine, proteins with surface L-histidine residue, lysozyme, cytochrome C, or without ribonuclease A. The results revealed that the proposed polymerization strategy could make significant contribution to the solution of chronic problems of fluorescent component introduction into polymers. Additionally, the fluorescent nanoparticles reported here could be used for selective separation and fluorescent monitoring purposes. Highlights: • Lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles • Direct incorporation of the fluorescent complex into polymeric backbone. • Imprinting by assistance of cupric ion coordination into nanoparticles • Evaluation of the chiral biorecognition ability of nanoparticles • Simultaneous selective separation and fluorescent monitoring.

  11. Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Aleš Procházka

    2018-05-01

    Full Text Available Multimodal signal analysis based on sophisticated sensors, efficient communicationsystems and fast parallel processing methods has a rapidly increasing range of multidisciplinaryapplications. The present paper is devoted to pattern recognition, machine learning, and the analysisof sleep stages in the detection of sleep disorders using polysomnography (PSG data, includingelectroencephalography (EEG, breathing (Flow, and electro-oculogram (EOG signals. The proposedmethod is based on the classification of selected features by a neural network system with sigmoidaland softmax transfer functions using Bayesian methods for the evaluation of the probabilities of theseparate classes. The application is devoted to the analysis of the sleep stages of 184 individualswith different diagnoses, using EEG and further PSG signals. Data analysis points to an averageincrease of the length of the Wake stage by 2.7% per 10 years and a decrease of the length of theRapid Eye Movement (REM stages by 0.8% per 10 years. The mean classification accuracy for givensets of records and single EEG and multimodal features is 88.7% ( standard deviation, STD: 2.1 and89.6% (STD:1.9, respectively. The proposed methods enable the use of adaptive learning processesfor the detection and classification of health disorders based on prior specialist experience andman–machine interaction.

  12. Synthesis of molecularly imprinted silica nanospheres embedded mercaptosuccinic acid-coated CdTe quantum dots for selective recognition of λ-cyhalothrin

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Meng, Minjia; Song, Zhilong; Gao, Lin; Li, Hongji [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Dai, Jiangdong; Zhou, Zhiping [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Chunxiang, E-mail: weixiaokeyan@163.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Pan, Jianming; Yu, Ping; Yan, Yongsheng [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2014-09-15

    In this study, a simple procedure for the determination of λ-cyhalothrin was reported. CdTe quantum dots (QDs) capped by molecularly imprinted polymers (MIPs) were prepared and characterized by spectrofluorometer, Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM) and scanning electron microscope (SEM). Mercaptosuccinic acid (MSA) was chosen as a stabilizer for CdTe QDs synthesis. The MSA stabilizer which comprises both thioglycolic acid (TGA)-like and 3-mercaptopropionic acid (MPA)-like moieties could accelerate the whole growth process of CdTe QDs comparing with TGA-like or MPA-like stabilizer. Meanwhile, the spectrofluorometer was used to evaluate the optical stability, effect of pH, and selective and sensitive determination of λ-cyhalothrin (LC). Moreover, LC could quench the fluorescence of the molecularly imprinted silica nanospheres (CdTe@SiO{sub 2}@MIPs) in a concentration-dependent manner, which was best described by a Stern–Volmer-type equation. - Highlights: • We choose Mercaptosuccinic acid (MSA) as the stabilizer for CdTe QDs synthesis. • The composite materials were prepared by the reverse microemulsion method. • The composite materials can be used for the direct analysis of relevant real samples.

  13. Factors affecting nucleolytic efficiency of some ternary metal complexes with DNA binding and recognition domains. Crystal and molecular structure of Zn(phen)(edda).

    Science.gov (United States)

    Seng, Hoi-Ling; Ong, Han-Kiat Alan; Rahman, Raja Noor Zaliha Raja Abd; Yamin, Bohari M; Tiekink, Edward R T; Tan, Kong Wai; Maah, Mohd Jamil; Caracelli, Ignez; Ng, Chew Hee

    2008-11-01

    The binding selectivity of the M(phen)(edda) (M=Cu, Co, Ni, Zn; phen=1,10-phenanthroline, edda=ethylenediaminediacetic acid) complexes towards ds(CG)(6), ds(AT)(6) and ds(CGCGAATTCGCG) B-form oligonucleotide duplexes were studied by CD spectroscopy and molecular modeling. The binding mode is intercalation and there is selectivity towards AT-sequence and stacking preference for A/A parallel or diagonal adjacent base steps in their intercalation. The nucleolytic properties of these complexes were investigated and the factors affecting the extent of cleavage were determined to be: concentration of complex, the nature of metal(II) ion, type of buffer, pH of buffer, incubation time, incubation temperature, and the presence of hydrogen peroxide or ascorbic acid as exogenous reagents. The fluorescence property of these complexes and its origin were also investigated. The crystal structure of the Zn(phen)(edda) complex is reported in which the zinc atom displays a distorted trans-N(4)O(2) octahedral geometry; the crystal packing features double layers of complex molecules held together by extensive hydrogen bonding that inter-digitate with adjacent double layers via pi...pi interactions between 1,10-phenanthroline residues. The structure is compared with that of the recently described copper(II) analogue and, with the latter, included in molecular modeling.

  14. Chiral recognition of proteins having L-histidine residues on the surface with lanthanide ion complex incorporated-molecularly imprinted fluorescent nanoparticles.

    Science.gov (United States)

    Uzun, Lokman; Uzek, Recep; Senel, Serap; Say, Ridvan; Denizli, Adil

    2013-08-01

    In this study, lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles were synthesized. A combination of three novel approaches was applied for the purpose. First, lanthanide ions [Terbium(III)] were complexed with N-methacryloyl-L-histidine (MAH), polymerizable derivative of L-histidine amino acid, in order to incorporate the complex directly into the polymeric backbone. At the second stage, L-histidine molecules imprinted nanoparticles were utilized instead of whole protein imprinting in order to avoid whole drawbacks such as fragility, complexity, denaturation tendency, and conformation dependency. At the third stage following the first two steps mentioned above, imprinted L-histidine was coordinated with cupric ions [Cu(II)] to conduct the study under mild conditions. Then, molecularly imprinted fluorescent nanoparticles synthesized were used for L-histidine adsorption from aqueous solution to optimize conditions for adsorption and fluorimetric detection. Finally, usability of nanoparticles was investigated for chiral biorecognition using stereoisomer, D-histidine, racemic mixture, D,L-histidine, proteins with surface L-histidine residue, lysozyme, cytochrome C, or without ribonuclease A. The results revealed that the proposed polymerization strategy could make significant contribution to the solution of chronic problems of fluorescent component introduction into polymers. Additionally, the fluorescent nanoparticles reported here could be used for selective separation and fluorescent monitoring purposes. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Radiological and Environmental Research Division annual report: Fundamental Molecular Physics and Chemistry, October 1977-September 1978. [Summary of research activities at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, R. E.; Inokuti, Mitio [eds.

    1978-01-01

    Research presented includes 32 papers, six of which have appeared previously in ERA, and 26 appear in this issue of ERA. Molecular physics and chemistry including photoionization, molecular properties, oscillator strengths, scattering, shape resonances, and photoelectrons are covered. A list of publications is included. (JFP)

  16. Synthesis, recognition and evaluation of molecularly imprinted polymer nanoparticle using miniemulsion polymerization for controlled release and analysis of risperidone in human plasma samples

    International Nuclear Information System (INIS)

    Asadi, Ebadullah; Azodi-Deilami, Saman; Abdouss, Majid; Kordestani, Davood; Rahimi, Alireza; Asadi, Somayeh

    2014-01-01

    We prepared high selective imprinted nanoparticle polymers by a miniemulsion polymerization technique, using risperidone as the template, MAA as the functional monomers, and TRIM as the cross-linker in acetonitrile as solvent. The morphology of the nanoparticles determined by scanning electron microscopy (SEM) images and drug release, binding properties and dynamic light scattering (DLS) of molecularly imprinted polymers (MIPs) were studied. Controlled release of risperidone from nanoparticles was investigated through in 1% wt sodium dodecyl sulfate aqueous solution and by measuring the absorbance by HPLC-UV. The results showed that the imprinted nanoparticles exhibited a higher binding level and slower release rate than non-imprinted nanoparticles, which contributed to interaction of risperidone with imprinted cavities within nanoparticles. Furthermore, the results from HPLC showed good precision (5% for 50.0 µg L -1 ) and recoveries (between 86-91) using MIP from human plasma samples

  17. The use of coenzyme Q0 as a template in the development of a molecularly imprinted polymer for the selective recognition of coenzyme Q10.

    Science.gov (United States)

    Contin, Mario; Flor, Sabrina; Martinefski, Manuela; Lucangioli, Silvia; Tripodi, Valeria

    2014-01-07

    In this work, a novel molecularly imprinted polymer (MIP) for use as a solid phase extraction sorbent was developed for the determination of coenzyme Q10 (CoQ10) in liver extract. CoQ10 is an essential cofactor in mitochondrial oxidative phosphorylation and a powerful antioxidant agent found in low concentrations in biological samples. This fact and its high hydrophobicity make the analysis of CoQ10 technically challenging. Accordingly, a MIP was synthesised using coenzyme Q0 as the template, methacrylic acid as the functional monomer, acetonitrile as the porogen, ethylene glycol dimethacrylate as the crosslinker and benzoyl peroxide as the initiator. Various parameters affecting the polymer preparation and extraction efficiency were evaluated. Morphological characterisation of the MIP and its proper comparison with C18 as a sorbent in solid phase extraction were performed. The optimal conditions for the molecularly imprinted solid phase extraction (MISPE) consisted of 400 μL of sample mixed with 30 mg of MIP and 600 μL of water to reach the optimum solution loading. The loading was followed by a washing step consisting of 1 mL of a 1-propanol solution (1-propanol:water, 30:70,v/v) and elution with 1 mL of 1-propanol. After clean-up, the CoQ10 in the samples was analysed by high performance liquid chromatography. The extraction recoveries were higher than 73.7% with good precision (3.6-8.3%). The limits of detection and quantification were 2.4 and 7.5 μg g(-1), respectively, and a linear range between 7.5 and 150 μg g(-1) of tissue was achieved. The new MISPE procedure provided a successful clean-up for the determination of CoQ10 in a complex matrix. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Structural and molecular dynamics studies of a C1-oxidizing lytic polysaccharide monooxygenase from Heterobasidion irregulare reveal amino acids important for substrate recognition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bing [Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala Sweden; Kognole, Abhishek A. [Department of Chemical and Materials Engineering, University of Kentucky, Lexington KY USA; Wu, Miao [Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala Sweden; Westereng, Bjørge [Department of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences, Ås Norway; Crowley, Michael F. [Biosciences Center, National Renewable Energy Laboratory, Golden CO USA; Kim, Seonah [Biosciences Center, National Renewable Energy Laboratory, Golden CO USA; Dimarogona, Maria [Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala Sweden; Department of Chemical Engineering, University of Patras, Greece; Payne, Christina M. [Department of Chemical and Materials Engineering, University of Kentucky, Lexington KY USA; Directorate of Engineering, Division of Chemical, Bioengineering, Environmental, and Transport Systems, National Science Foundation, Alexandria VA USA; Sandgren, Mats [Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala Sweden

    2018-04-24

    Lytic polysaccharide monooxygenases (LPMOs) are a group of recently discovered enzymes that play important roles in the decomposition of recalcitrant polysaccharides. Here, we report the biochemical, structural, and computational characterization of an LPMO from the white-rot fungus Heterobasidion irregulare (HiLPMO9B). This enzyme oxidizes cellulose at the C1 carbon of glycosidic linkages. The crystal structure of HiLPMO9B was determined at 2.1 A resolution using X-ray crystallography. Unlike the majority of the currently available C1-specific LPMO structures, the HiLPMO9B structure contains an extended L2 loop, connecting ..beta..-strands ..beta..2 and ..beta..3 of the ..beta..-sandwich structure. Molecular dynamics (MD) simulations suggest roles for both aromatic and acidic residues in the substrate binding of HiLPMO9B, with the main contribution from the residues located on the extended region of the L2 loop (Tyr20) and the LC loop (Asp205, Tyr207, and Glu210). Asp205 and Glu210 were found to be involved in the hydrogen bonding with the hydroxyl group of the C6 carbon of glucose moieties directly or via a water molecule. Two different binding orientations were observed over the course of the MD simulations. In each orientation, the active-site copper of this LPMO preferentially skewed toward the pyranose C1 of the glycosidic linkage over the targeted glycosidic bond. This study provides additional insight into cellulose binding by C1-specific LPMOs, giving a molecular-level picture of active site substrate interactions.

  19. Molecular characterization of HIV-1 CRF01_AE in Mekong Delta, Vietnam, and impact of T-cell epitope mutations on HLA recognition (ANRS 12159.

    Directory of Open Access Journals (Sweden)

    Estibaliz Lazaro

    Full Text Available BACKGROUND: To date, 11 HIV-1 subtypes and 48 circulating recombinant forms have been described worldwide. The underlying reason why their distribution is so heterogeneous is not clear. Host genetic factors could partly explain this distribution. The aim of this study was to describe HIV-1 strains circulating in an unexplored area of Mekong Delta, Vietnam, and to assess the impact of optimal epitope mutations on HLA binding. METHODS: We recruited 125 chronically antiretroviral-naive HIV-1-infected subjects from five cities in the Mekong Delta. We performed high-resolution DNA typing of HLA class I alleles, sequencing of Gag and RT-Prot genes and phylogenetic analysis of the strains. Epitope mutations were analyzed in patients bearing the HLA allele restricting the studied epitope. Optimal wild-type epitopes from the Los Alamos database were used as reference. T-cell epitope recognition was predicted using the immune epitope database tool according to three different scores involved in antigen processing (TAP and proteasome scores and HLA binding (MHC score. RESULTS: All sequences clustered with CRF01_AE. HLA class I genotyping showed the predominance of Asian alleles as A*11:01 and B*46:01 with a Vietnamese specificity held by two different haplotypes. The percentage of homology between Mekong and B consensus HIV-1 sequences was above 85%. Divergent epitopes had TAP and proteasome scores comparable with wild-type epitopes. MHC scores were significantly lower in divergent epitopes with a mean of 2.4 (±0.9 versus 2 (±0.7 in non-divergent ones (p<0.0001. CONCLUSIONS: Our study confirms the wide predominance of CRF01_AE in the Mekong Delta where patients harbor a specific HLA pattern. Moreover, it demonstrates the lower MHC binding affinity among divergent epitopes. This weak immune pressure combined with a narrow genetic diversity favors immune escape and could explain why CRF01_AE is still predominant in Vietnam, particularly in the Mekong area.

  20. Molecular dynamics simulations shed light on the enthalpic and entropic driving forces that govern the sequence specific recognition between netropsin and DNA.

    Science.gov (United States)

    Dolenc, Jozica; Gerster, Sarah; van Gunsteren, Wilfred F

    2010-09-02

    With the aim to gain a better understanding of the various driving forces that govern sequence specific DNA minor groove binding, we performed a thermodynamic analysis of netropsin binding to an AT-containing and to a set of six mixed AT/GC-containing binding sequences in the DNA minor groove. The relative binding free energies obtained using molecular dynamics simulations and free energy calculations show significant variations with the binding sequence. While the introduction of a GC base pair in the middle or close to the middle of the binding site is unfavorable for netropsin binding, a GC base pair at the end of the binding site appears to have no negative influence on the binding. The results of the structural and energetic analyses of the netropsin-DNA complexes reveal that the differences in the calculated binding affinities cannot be explained solely in terms of netropsin-DNA hydrogen-bonding or interaction energies. In addition, solvation effects and entropic contributions to the relative binding free energy provide a more complete picture of the various factors determining binding. Analysis of the relative binding entropy indicates that its magnitude is highly sequence-dependent, with the ratio |TDeltaDeltaS|/|DeltaDeltaH| ranging from 0.07 for the AAAGA to 1.7 for the AAGAG binding sequence, respectively.

  1. Structure of CC Chemokine Receptor 5 with a Potent Chemokine Antagonist Reveals Mechanisms of Chemokine Recognition and Molecular Mimicry by HIV

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Han, Gye Won; Abagyan, Ruben; Wu, Beili; Stevens, Raymond C.; Cherezov, Vadim; Kufareva, Irina; Handel, Tracy M. (USC); (Chinese Aca. Sci.); (UCSD)

    2017-06-01

    CCR5 is the primary chemokine receptor utilized by HIV to infect leukocytes, whereas CCR5 ligands inhibit infection by blocking CCR5 engagement with HIV gp120. To guide the design of improved therapeutics, we solved the structure of CCR5 in complex with chemokine antagonist [5P7]CCL5. Several structural features appeared to contribute to the anti-HIV potency of [5P7]CCL5, including the distinct chemokine orientation relative to the receptor, the near-complete occupancy of the receptor binding pocket, the dense network of intermolecular hydrogen bonds, and the similarity of binding determinants with the FDA-approved HIV inhibitor Maraviroc. Molecular modeling indicated that HIV gp120 mimicked the chemokine interaction with CCR5, providing an explanation for the ability of CCR5 to recognize diverse ligands and gp120 variants. Our findings reveal that structural plasticity facilitates receptor-chemokine specificity and enables exploitation by HIV, and provide insight into the design of small molecule and protein inhibitors for HIV and other CCR5-mediated diseases.

  2. The development of a new optical sensor based on the Mn doped ZnS quantum dots modified with the molecularly imprinted polymers for sensitive recognition of florfenicol

    Science.gov (United States)

    Sadeghi, Susan; Jahani, Moslem; Belador, Foroogh

    2016-04-01

    The Mn doped ZnS quantum dots (Mn:ZnS QDs) capped with the florfenicol molecularly imprinted polymer (Mn:ZnS QDs@MIP) were prepared via the sol-gel surface imprinting approach using 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethoxysilane (TEOS) as the cross-linker for the optosensing of the florfenicol. Transmission electron microscopy (TEM), X-ray diffractometer, IR spectroscopy, UV-Vis absorption spectrophotometry, and spectrofluorometry were used to elucidate the formation, morphology, and identification of the products. To illustrate the usefulness of the new imprinted material, the non-imprinted coated Mn:ZnS QDs (Mn:ZnS QDs@NIP) were synthesized without the presence of the florfenicol. It was revealed that the fluorescence (FL) intensity of the Mn:ZnS QDs@MIP increased with increasing the FF concentration. Under the optimal conditions, changes in the FL intensity in the presence of the target molecule showed a linear response in the concentration range of 30-700 μmol L- 1 with a detection limit of 24 μmol L- 1. The developed method was finally applied successfully to the determination of FF in different meat samples with satisfactory recoveries.

  3. The development of a new optical sensor based on the Mn doped ZnS quantum dots modified with the molecularly imprinted polymers for sensitive recognition of florfenicol.

    Science.gov (United States)

    Sadeghi, Susan; Jahani, Moslem; Belador, Foroogh

    2016-04-15

    The Mn doped ZnS quantum dots (Mn:ZnS QDs) capped with the florfenicol molecularly imprinted polymer (Mn:ZnS QDs@MIP) were prepared via the sol-gel surface imprinting approach using 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethoxysilane (TEOS) as the cross-linker for the optosensing of the florfenicol. Transmission electron microscopy (TEM), X-ray diffractometer, IR spectroscopy, UV-Vis absorption spectrophotometry, and spectrofluorometry were used to elucidate the formation, morphology, and identification of the products. To illustrate the usefulness of the new imprinted material, the non-imprinted coated Mn:ZnS QDs (Mn:ZnS QDs@NIP) were synthesized without the presence of the florfenicol. It was revealed that the fluorescence (FL) intensity of the Mn:ZnS QDs@MIP increased with increasing the FF concentration. Under the optimal conditions, changes in the FL intensity in the presence of the target molecule showed a linear response in the concentration range of 30-700 μmol L(-1) with a detection limit of 24 μmol L(-1). The developed method was finally applied successfully to the determination of FF in different meat samples with satisfactory recoveries. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Halide anion solvation and recognition by a macro tri-cyclic tetra-ammonium host in an ionic liquid: a molecular dynamics stud

    International Nuclear Information System (INIS)

    Chaumont, A.; Wipff, G.

    2006-01-01

    We report a molecular dynamics study of halide anions X - and their inclusion complexes X - - L 4+ with a macro-tri-cyclic tetrahedral host L 4+ built from four quaternary ammonium sites, in an ionic liquid (IL) based on the 1-butyl-3-methyl-imidazolium (BMI + ) cation and the PF 6 - anion. The 'dry' and 'humid' forms of the [BMI][PF 6 ] IL are compared, showing the importance of IL ions in the 'dry' IL and, in some cases, of water molecules in the 'humid' IL. In the 'dry' IL the F - , Cl - , Br - and I - un-complexed halides are surrounded by 4-5 BMI + cations whose binding mode evolves from hydrogen bonding to facial coordination along this series. Solvent humidity has the largest impact on the solvation of F - whose first shell BMI + cations are all displaced by H 2 O molecules, while the first solvation shell of Cl - , Br - and I - comprises 3-4 BMI + cations plus ca. 4 H 2 O molecules. The solvation of the L 4+ host and of its X - - L 4+ complex mainly involves PF 6 - anions in the 'dry' IL, and additional H 2 O molecules in the 'humid' IL. The question of anion binding selectivity is addressed by free energy perturbation calculations which predict that, in the 'dry' liquid, F - is preferred over Cl - , Br - and I - , which contrasts with the aqueous solution where L 4+ is selective for Cl - . In the 'humid' liquid however, there is no F - /Cl - discrimination, showing the importance of small amounts of water on the complexation selectivity. (authors)

  5. Idiosyncratic recognition of UUG/UUA codons by modified nucleoside 5-taurinomethyluridine, τm5U present at 'wobble' position in anticodon loop of tRNALeu: A molecular modeling approach.

    Directory of Open Access Journals (Sweden)

    Asmita S Kamble

    Full Text Available Lack of naturally occurring modified nucleoside 5-taurinomethyluridine (τm5U at the 'wobble' 34th position in tRNALeu causes mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS. The τm5U34 specifically recognizes UUG and UUA codons. Structural consequences of τm5U34 to read cognate codons have not been studied so far in detail at the atomic level. Hence, 50ns multiple molecular dynamics (MD simulations of various anticodon stem loop (ASL models of tRNALeu in presence and absence of τm5U34 along with UUG and UUA codons were performed to explore the dynamic behaviour of τm5U34 during codon recognition process. The MD simulation results revealed that τm5U34 recognizes G/A ending codons by 'wobble' as well as a novel 'single' hydrogen bonding interactions. RMSD and RMSF values indicate the comparative stability of the ASL models containing τm5U34 modification over the other models, lacking τm5U34. Another MD simulation study of 55S mammalian mitochondrial rRNA with tRNALeu showed crucial interactions between the A-site residues, A918, A919, G256 and codon-anticodon bases. Thus, these results could improve our understanding about the decoding efficiency of human mt tRNALeu with τm5U34 to recognize UUG and UUA codons.

  6. Annual report 1976

    International Nuclear Information System (INIS)

    Nilsson, A.

    1976-01-01

    This annual report contains research reports from the various groups of the Research Institute of Physics, Stockholm. Reports are made by workers in the Atomic and Molecular Physics group, the Surface Physics group, the Nuclear Physics group, the group researching into High Energy Physics and related topics and the Instrumentation and Methods group. The report also contains a list of the papers published by members of the Institute during the year and a list of the theses which were presented. (B.D.)

  7. Molecular characterization of UGT94F2 and UGT86C4, two glycosyltransferases from Picrorhiza kurrooa: comparative structural insight and evaluation of substrate recognition.

    Directory of Open Access Journals (Sweden)

    Wajid Waheed Bhat

    Full Text Available Uridine diphosphate glycosyltransferases (UGTs are pivotal in the process of glycosylation for decorating natural products with sugars. It is one of the versatile mechanisms in determining chemical complexity and diversity for the production of suite of pharmacologically active plant natural products. Picrorhiza kurrooa is a highly reputed medicinal herb known for its hepato-protective properties which are attributed to a novel group of iridoid glycosides known as picrosides. Although the plant is well studied in terms of its pharmacological properties, very little is known about the biosynthesis of these important secondary metabolites. In this study, we identified two family-1 glucosyltransferases from P. kurrooa. The full length cDNAs of UGT94F4 and UGT86C4 contained open reading frames of 1455 and 1422 nucleotides, encoding polypeptides of 484 and 473 amino acids respectively. UGT94F2 and UGT86C4 showed differential expression pattern in leaves, rhizomes and inflorescence. To elucidate whether the differential expression pattern of the two Picrorhiza UGTs correlate with transcriptional regulation via their promoters and to identify elements that could be recognized by known iridoid-specific transcription factors, upstream regions of each gene were isolated and scanned for putative cis-regulatory elements. Interestingly, the presence of cis-regulatory elements within the promoter regions of each gene correlated positively with their expression profiles in response to different phytohormones. HPLC analysis of picrosides extracted from different tissues and elicitor-treated samples showed a significant increase in picroside levels, corroborating well with the expression profile of UGT94F2 possibly indicating its implication in picroside biosynthesis. Using homology modeling and molecular docking studies, we provide an insight into the donor and acceptor specificities of both UGTs identified in this study. UGT94F2 was predicted to be an iridoid

  8. Program and abstracts of the 25. Annual meeting of the Brazilian Society on Biochemistry and Molecular Biology; Programa e resumos da 25. Reuniao anual da Sociedade Brasileira de Bioquimica e Biologia Molecular

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The meeting was about biochemistry and molecular biology.In this meeting it was also discussed the following subjects: biotechnology, metabolism, enzymes, proteins, immunology, drugs and others related topics.

  9. Face Detection and Recognition

    National Research Council Canada - National Science Library

    Jain, Anil K

    2004-01-01

    This report describes research efforts towards developing algorithms for a robust face recognition system to overcome many of the limitations found in existing two-dimensional facial recognition systems...

  10. Performance appraisal and merit recognition exercise 2007

    CERN Multimedia

    HR Department

    2006-01-01

    The 2007 performance appraisal and merit recognition exercise will start in the usual way with annual interviews between staff and their supervisors. This year, these interviews should be held in the period from 8 January 2007 to 16 April 2007. Interconnection with the 5-yearly review, a number of modifications to the procedures relating to the performance appraisal and merit recognition are currently under study. Administrative Circular No. 26 (Procedures governing the Career Development of Staff Members) and the electronic MAPS form in EDH are being reviewed and will be available from January onwards. HR Department will shortly provide further information on this subject. Human Resources Department Tel. 73566

  11. Graphical symbol recognition

    OpenAIRE

    K.C. , Santosh; Wendling , Laurent

    2015-01-01

    International audience; The chapter focuses on one of the key issues in document image processing i.e., graphical symbol recognition. Graphical symbol recognition is a sub-field of a larger research domain: pattern recognition. The chapter covers several approaches (i.e., statistical, structural and syntactic) and specially designed symbol recognition techniques inspired by real-world industrial problems. It, in general, contains research problems, state-of-the-art methods that convey basic s...

  12. Designer molecule for molecular recognition and photoinduced ...

    Indian Academy of Sciences (India)

    amitava

    Signaling unit: Transform the cation-receptor interaction into output signal. 1H NMR ..... solution of Hg2+ (10 μM) and then to a water/ethanol (7/3 v/v) solution of solution of Hg2+ (10 μM) and .... System extended in the [010] direction. 2.5 fs.

  13. Molecular Recognition Studies on Naphthyridine Derivatives

    Directory of Open Access Journals (Sweden)

    José Carlos Iglesias-Sánchez

    2010-03-01

    Full Text Available The association constants Kb of three hosts I–III designed to have both enhanced hydrogen bonding donor strength and conformational preorganization with biotin analogues 1–5 are reported. 1H-NMR titrations under two different concentration conditions have been employed to determine the association constants Kb. A statistical analysis using a presence absence matrix has been applied to calculate the different contributions. Hydrogen bond interactions make naphthyridine derivatives II and III potent binders and effective receptors for (+-biotin methyl ester (1, due to the complex stabilization by additional hydrogen bonds.

  14. Recognition and Toleration

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    Recognition and toleration are ways of relating to the diversity characteristic of multicultural societies. The article concerns the possible meanings of toleration and recognition, and the conflict that is often claimed to exist between these two approaches to diversity. Different forms...... or interpretations of recognition and toleration are considered, confusing and problematic uses of the terms are noted, and the compatibility of toleration and recognition is discussed. The article argues that there is a range of legitimate and importantly different conceptions of both toleration and recognition...

  15. Accessing Specific Peptide Recognition by Combinatorial Chemistry

    DEFF Research Database (Denmark)

    Li, Ming

    Molecular recognition is at the basis of all processes for life, and plays a central role in many biological processes, such as protein folding, the structural organization of cells and organelles, signal transduction, and the immune response. Hence, my PhD project is entitled “Accessing Specific...... Peptide Recognition by Combinatorial Chemistry”. Molecular recognition is a specific interaction between two or more molecules through noncovalent bonding, such as hydrogen bonding, metal coordination, van der Waals forces, π−π, hydrophobic, or electrostatic interactions. The association involves kinetic....... Combinatorial chemistry was invented in 1980s based on observation of functional aspects of the adaptive immune system. It was employed for drug development and optimization in conjunction with high-throughput synthesis and screening. (chapter 2) Combinatorial chemistry is able to rapidly produce many thousands...

  16. 8 CFR 1292.2 - Organizations qualified for recognition; requests for recognition; withdrawal of recognition...

    Science.gov (United States)

    2010-01-01

    ...; requests for recognition; withdrawal of recognition; accreditation of representatives; roster. 1292.2...; requests for recognition; withdrawal of recognition; accreditation of representatives; roster. (a) Qualifications of organizations. A non-profit religious, charitable, social service, or similar organization...

  17. Improved hemicryptophane hosts for the stereoselective recognition of glucopyranosides

    Czech Academy of Sciences Publication Activity Database

    Schmitt, A.; Perraud, O.; Payet, E.; Chatelet, B.; Bousquet, B.; Valls, M.; Padula, Daniele; Di Bari, L.; Dutasta, J. P.; Martinez, A.

    2014-01-01

    Roč. 12, č. 24 (2014), s. 4211-4217 ISSN 1477-0520 Institutional support: RVO:61388963 Keywords : hydrogen-bonding receptors * molecular recognition * artificial receptors Subject RIV: CC - Organic Chemistry Impact factor: 3.562, year: 2014

  18. Optical Pattern Recognition

    Science.gov (United States)

    Yu, Francis T. S.; Jutamulia, Suganda

    2008-10-01

    Contributors; Preface; 1. Pattern recognition with optics Francis T. S. Yu and Don A. Gregory; 2. Hybrid neural networks for nonlinear pattern recognition Taiwei Lu; 3. Wavelets, optics, and pattern recognition Yao Li and Yunglong Sheng; 4. Applications of the fractional Fourier transform to optical pattern recognition David Mendlovic, Zeev Zalesky and Haldum M. Oxaktas; 5. Optical implementation of mathematical morphology Tien-Hsin Chao; 6. Nonlinear optical correlators with improved discrimination capability for object location and recognition Leonid P. Yaroslavsky; 7. Distortion-invariant quadratic filters Gregory Gheen; 8. Composite filter synthesis as applied to pattern recognition Shizhou Yin and Guowen Lu; 9. Iterative procedures in electro-optical pattern recognition Joseph Shamir; 10. Optoelectronic hybrid system for three-dimensional object pattern recognition Guoguang Mu, Mingzhe Lu and Ying Sun; 11. Applications of photrefractive devices in optical pattern recognition Ziangyang Yang; 12. Optical pattern recognition with microlasers Eung-Gi Paek; 13. Optical properties and applications of bacteriorhodopsin Q. Wang Song and Yu-He Zhang; 14. Liquid-crystal spatial light modulators Aris Tanone and Suganda Jutamulia; 15. Representations of fully complex functions on real-time spatial light modulators Robert W. Cohn and Laurence G. Hassbrook; Index.

  19. DNA recognition by synthetic constructs.

    Science.gov (United States)

    Pazos, Elena; Mosquera, Jesús; Vázquez, M Eugenio; Mascareñas, José L

    2011-09-05

    The interaction of transcription factors with specific DNA sites is key for the regulation of gene expression. Despite the availability of a large body of structural data on protein-DNA complexes, we are still far from fully understanding the molecular and biophysical bases underlying such interactions. Therefore, the development of non-natural agents that can reproduce the DNA-recognition properties of natural transcription factors remains a major and challenging goal in chemical biology. In this review we summarize the basics of double-stranded DNA recognition by transcription factors, and describe recent developments in the design and preparation of synthetic DNA binders. We mainly focus on synthetic peptides that have been designed by following the DNA interaction of natural proteins, and we discuss how the tools of organic synthesis can be used to make artificial constructs equipped with functionalities that introduce additional properties to the recognition process, such as sensing and controllability. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Pattern recognition & machine learning

    CERN Document Server

    Anzai, Y

    1992-01-01

    This is the first text to provide a unified and self-contained introduction to visual pattern recognition and machine learning. It is useful as a general introduction to artifical intelligence and knowledge engineering, and no previous knowledge of pattern recognition or machine learning is necessary. Basic for various pattern recognition and machine learning methods. Translated from Japanese, the book also features chapter exercises, keywords, and summaries.

  1. NERSC 2001 Annual Report; ANNUAL

    International Nuclear Information System (INIS)

    Hules, John

    2001-01-01

    The National Energy Research Scientific Computing Center (NERSC) is the primary computational resource for scientific research funded by the DOE Office of Science. The Annual Report for FY2001 includes a summary of recent computational science conducted on NERSC systems (with abstracts of significant and representative projects); information about NERSC's current systems and services; descriptions of Berkeley Lab's current research and development projects in applied mathematics, computer science, and computational science; and a brief summary of NERSC's Strategic Plan for 2002-2005

  2. Statistical Pattern Recognition

    CERN Document Server

    Webb, Andrew R

    2011-01-01

    Statistical pattern recognition relates to the use of statistical techniques for analysing data measurements in order to extract information and make justified decisions.  It is a very active area of study and research, which has seen many advances in recent years. Applications such as data mining, web searching, multimedia data retrieval, face recognition, and cursive handwriting recognition, all require robust and efficient pattern recognition techniques. This third edition provides an introduction to statistical pattern theory and techniques, with material drawn from a wide range of fields,

  3. Molecular threading and tunable molecular recognition on DNA origami nanostructures.

    Science.gov (United States)

    Wu, Na; Czajkowsky, Daniel M; Zhang, Jinjin; Qu, Jianxun; Ye, Ming; Zeng, Dongdong; Zhou, Xingfei; Hu, Jun; Shao, Zhifeng; Li, Bin; Fan, Chunhai

    2013-08-21

    The DNA origami technology holds great promise for the assembly of nanoscopic technological devices and studies of biochemical reactions at the single-molecule level. For these, it is essential to establish well controlled attachment of functional materials to predefined sites on the DNA origami nanostructures for reliable measurements and versatile applications. However, the two-sided nature of the origami scaffold has shown limitations in this regard. We hypothesized that holes of the commonly used two-dimensional DNA origami designs are large enough for the passage of single-stranded (ss)-DNA. Sufficiently long ssDNA initially located on one side of the origami should thus be able to "thread" to the other side through the holes in the origami sheet. By using an origami sheet attached with patterned biotinylated ssDNA spacers and monitoring streptavidin binding with atomic force microscopic (AFM) imaging, we provide unambiguous evidence that the biotin ligands positioned on one side have indeed threaded through to the other side. Our finding reveals a previously overlooked critical design feature that should provide new interpretations to previous experiments and new opportunities for the construction of origami structures with new functional capabilities.

  4. Paradigms in object recognition

    International Nuclear Information System (INIS)

    Mutihac, R.; Mutihac, R.C.

    1999-09-01

    A broad range of approaches has been proposed and applied for the complex and rather difficult task of object recognition that involves the determination of object characteristics and object classification into one of many a priori object types. Our paper revises briefly the three main different paradigms in pattern recognition, namely Bayesian statistics, neural networks, and expert systems. (author)

  5. Infant Visual Recognition Memory

    Science.gov (United States)

    Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.

    2004-01-01

    Visual recognition memory is a robust form of memory that is evident from early infancy, shows pronounced developmental change, and is influenced by many of the same factors that affect adult memory; it is surprisingly resistant to decay and interference. Infant visual recognition memory shows (a) modest reliability, (b) good discriminant…

  6. Recognition and Toleration

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    Recognition and toleration are ways of relating to the diversity characteristic of multicultural societies. The article concerns the possible meanings of toleration and recognition, and the conflict that is often claimed to exist between these two approaches to diversity. Different forms or inter...

  7. Success with voice recognition.

    Science.gov (United States)

    Sferrella, Sheila M

    2003-01-01

    You need a compelling reason to implement voice recognition technology. At my institution, the compelling reason was a turnaround time for Radiology results of more than two days. Only 41 percent of our reports were transcribed and signed within 24 hours. In November 1998, a team from Lehigh Valley Hospital went to RSNA and reviewed every voice system on the market. The evaluation was done with the radiologist workflow in mind, and we came back from the meeting with the vendor selection completed. The next steps included developing a business plan, approval of funds, reference calls to more than 15 sites and contract negotiation, all of which took about six months. The department of Radiology at Lehigh Valley Hospital and Health Network (LVHHN) is a multi-site center that performs over 360,000 procedures annually. The department handles all modalities of radiology: general diagnosis, neuroradiology, ultrasound, CT Scan, MRI, interventional radiology, arthography, myelography, bone densitometry, nuclear medicine, PET imaging, vascular lab and other advanced procedures. The department consists of 200 FTEs and a medical staff of more than 40 radiologists. The budget is in the $10.3 million range. There are three hospital sites and four outpatient imaging center sites where services are provided. At Lehigh Valley Hospital, radiologists are not dedicated to one subspecialty, so implementing a voice system by modality was not an option. Because transcription was so far behind, we needed to eliminate that part of the process. As a result, we decided to deploy the system all at once and with the radiologists as editors. The planning and testing phase took about four months, and the implementation took two weeks. We deployed over 40 workstations and trained close to 50 physicians. The radiologists brought in an extra radiologist from our group for the two weeks of training. That allowed us to train without taking a radiologist out of the department. We trained three to six

  8. Challenging ocular image recognition

    Science.gov (United States)

    Pauca, V. Paúl; Forkin, Michael; Xu, Xiao; Plemmons, Robert; Ross, Arun A.

    2011-06-01

    Ocular recognition is a new area of biometric investigation targeted at overcoming the limitations of iris recognition performance in the presence of non-ideal data. There are several advantages for increasing the area beyond the iris, yet there are also key issues that must be addressed such as size of the ocular region, factors affecting performance, and appropriate corpora to study these factors in isolation. In this paper, we explore and identify some of these issues with the goal of better defining parameters for ocular recognition. An empirical study is performed where iris recognition methods are contrasted with texture and point operators on existing iris and face datasets. The experimental results show a dramatic recognition performance gain when additional features are considered in the presence of poor quality iris data, offering strong evidence for extending interest beyond the iris. The experiments also highlight the need for the direct collection of additional ocular imagery.

  9. Annual report

    International Nuclear Information System (INIS)

    1986-01-01

    This is the thirty-ninth annual report of the Atomic Energy Control Board. The period covered by this report is the year ending March 31, 1986. The Atomic Energy Control Board (AECB) was established in 1946, by the Atomic Energy Control Act (AEC Act), (Revised Statues of Canada (R.S.C.) 1970 cA19). It is a departmental corporation (Schedule B) within the meaning and purpose of the Financial Administration Act. The AECB controls the development, application and use of atomic energy in Canada, and participates on behalf of Canada in international measures of control. The AECB is also repsonsible for the administration of the Nuclear Liability Act, (R.S.C. 1970 c29 1st Supp) as amended, including the designation of nuclear installations and the prescription of basic insurance to be carried by the operators of such nuclear installations. The AECB reports to Parliament through a designated Minister, currently the Minister of Energy, Mines and Resources

  10. Supervised and Unsupervised Speaker Adaptation in the NIST 2005 Speaker Recognition Evaluation

    National Research Council Canada - National Science Library

    Hansen, Eric G; Slyh, Raymond E; Anderson, Timothy R

    2006-01-01

    Starting in 2004, the annual NIST Speaker Recognition Evaluation (SRE) has added an optional unsupervised speaker adaptation track where test files are processed sequentially and one may update the target model...

  11. 1994 MCAP annual report

    International Nuclear Information System (INIS)

    Harmony, S.C.; Boyack, B.E.

    1995-04-01

    VELCOR is an integrated, engineering-level computer code that models the progression of severe accidents in light water reactor (LWR) nuclear power plants. The entire spectrum of severe accident phenomena, including reactor coolant system and containment thermal-hydraulic response, core heatup, degradation and relocation, and fission product release and transport is treated in MELCOR in a unified framework for both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Its current uses include the estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications. Independent assessment efforts have been successfully completed by the US and international MELCOR user communities. Most of these independent assessment efforts have been conducted to support the needs and fulfill the requirements of the individual user organizations. The resources required to perform an extensive set of model and integral code assessments are large. A prudent approach to fostering code development and maturation is to coordinate the individual assessment efforts of the MELCOR user community. While retaining individual control over assessment resources, each organization using the MELCOR code could work with the other users to broaden assessment coverage and minimize duplication. In recognition of these considerations, the US Nuclear Regulatory Commission (US NRC) has initiated the MELCOR Cooperative Assessment Program (MCAP), a vehicle for coordinating and standardizing the assessment practices of the various MELCOR users. In addition, the user community will have a forum to better communicate lessons learned regarding MELCOR applications, capabilities, and user guidelines and limitations and to provide a user community perspective on code development needs and priorities. This second Annual Report builds on the foundation laid with the first Annual Report

  12. 8 CFR 292.2 - Organizations qualified for recognition; requests for recognition; withdrawal of recognition...

    Science.gov (United States)

    2010-01-01

    ...; requests for recognition; withdrawal of recognition; accreditation of representatives; roster. 292.2...; withdrawal of recognition; accreditation of representatives; roster. (a) Qualifications of organizations. A non-profit religious, charitable, social service, or similar organization established in the United...

  13. Harmonization versus Mutual Recognition

    DEFF Research Database (Denmark)

    Jørgensen, Jan Guldager; Schröder, Philipp

    The present paper examines trade liberalization driven by the coordination of product standards. For oligopolistic firms situated in separate markets that are initially sheltered by national standards, mutual recognition of standards implies entry and reduced profits at home paired with the oppor......The present paper examines trade liberalization driven by the coordination of product standards. For oligopolistic firms situated in separate markets that are initially sheltered by national standards, mutual recognition of standards implies entry and reduced profits at home paired...... countries and three firms, where firms first lobby for the policy coordination regime (harmonization versus mutual recognition), and subsequently, in case of harmonization, the global standard is auctioned among the firms. We discuss welfare effects and conclude with policy implications. In particular......, harmonized standards may fail to harvest the full pro-competitive effects from trade liberalization compared to mutual recognition; moreover, the issue is most pronounced in markets featuring price competition....

  14. CASE Recognition Awards.

    Science.gov (United States)

    Currents, 1985

    1985-01-01

    A total of 294 schools, colleges, and universities received prizes in this year's CASE Recognition program. Awards were given in: public relations programs, student recruitment, marketing, program pulications, news writing, fund raising, radio programming, school periodicals, etc. (MLW)

  15. Forensic speaker recognition

    NARCIS (Netherlands)

    Meuwly, Didier

    2013-01-01

    The aim of forensic speaker recognition is to establish links between individuals and criminal activities, through audio speech recordings. This field is multidisciplinary, combining predominantly phonetics, linguistics, speech signal processing, and forensic statistics. On these bases, expert-based

  16. The Recognition Of Fatigue

    DEFF Research Database (Denmark)

    Elsass, Peter; Jensen, Bodil; Mørup, Rikke

    2007-01-01

    Elsass P., Jensen B., Morup R., Thogersen M.H. (2007). The Recognition Of Fatigue: A qualitative study of life-stories from rehabilitation clients. International Journal of Psychosocial Rehabilitation. 11 (2), 75-87......Elsass P., Jensen B., Morup R., Thogersen M.H. (2007). The Recognition Of Fatigue: A qualitative study of life-stories from rehabilitation clients. International Journal of Psychosocial Rehabilitation. 11 (2), 75-87...

  17. Evaluating music emotion recognition

    DEFF Research Database (Denmark)

    Sturm, Bob L.

    2013-01-01

    A fundamental problem with nearly all work in music genre recognition (MGR)is that evaluation lacks validity with respect to the principal goals of MGR. This problem also occurs in the evaluation of music emotion recognition (MER). Standard approaches to evaluation, though easy to implement, do...... not reliably differentiate between recognizing genre or emotion from music, or by virtue of confounding factors in signals (e.g., equalization). We demonstrate such problems for evaluating an MER system, and conclude with recommendations....

  18. Quarterly, Bi-annual and Annual Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Quarterly, Bi-annual and Annual Reports are periodic reports issued for public release. For the deep set fishery these reports are issued quarterly and anually....

  19. Why recognition is rational

    Directory of Open Access Journals (Sweden)

    Clintin P. Davis-Stober

    2010-07-01

    Full Text Available The Recognition Heuristic (Gigerenzer and Goldstein, 1996; Goldstein and Gigerenzer, 2002 makes the counter-intuitive prediction that a decision maker utilizing less information may do as well as, or outperform, an idealized decision maker utilizing more information. We lay a theoretical foundation for the use of single-variable heuristics such as the Recognition Heuristic as an optimal decision strategy within a linear modeling framework. We identify conditions under which over-weighting a single predictor is a mini-max strategy among a class of a priori chosen weights based on decision heuristics with respect to a measure of statistical lack of fit we call ``risk''. These strategies, in turn, outperform standard multiple regression as long as the amount of data available is limited. We also show that, under related conditions, weighting only one variable and ignoring all others produces the same risk as ignoring the single variable and weighting all others. This approach has the advantage of generalizing beyond the original environment of the Recognition Heuristic to situations with more than two choice options, binary or continuous representations of recognition, and to other single variable heuristics. We analyze the structure of data used in some prior recognition tasks and find that it matches the sufficient conditions for optimality in our results. Rather than being a poor or adequate substitute for a compensatory model, the Recognition Heuristic closely approximates an optimal strategy when a decision maker has finite data about the world.

  20. Stigma-pollen recognition: a new look

    Directory of Open Access Journals (Sweden)

    C. Dumas

    2014-01-01

    Full Text Available During the last two decades, there have been several conceptual developments in our understanding of pollen-stigma recognition and molecular mechanisms involved. The main models proposed are compared. Based on additional data a hypothesis to complete these models especially for pollen hydration and adhesion is proposed. After attachment of the pollen to the stigma surface a close interaction exists involving lipoproteic membrane-like compounds (pollenkitt and stigma pellicle and pollen agglutinating ability.

  1. Object recognition memory: neurobiological mechanisms of encoding, consolidation and retrieval.

    Science.gov (United States)

    Winters, Boyer D; Saksida, Lisa M; Bussey, Timothy J

    2008-07-01

    Tests of object recognition memory, or the judgment of the prior occurrence of an object, have made substantial contributions to our understanding of the nature and neurobiological underpinnings of mammalian memory. Only in recent years, however, have researchers begun to elucidate the specific brain areas and neural processes involved in object recognition memory. The present review considers some of this recent research, with an emphasis on studies addressing the neural bases of perirhinal cortex-dependent object recognition memory processes. We first briefly discuss operational definitions of object recognition and the common behavioural tests used to measure it in non-human primates and rodents. We then consider research from the non-human primate and rat literature examining the anatomical basis of object recognition memory in the delayed nonmatching-to-sample (DNMS) and spontaneous object recognition (SOR) tasks, respectively. The results of these studies overwhelmingly favor the view that perirhinal cortex (PRh) is a critical region for object recognition memory. We then discuss the involvement of PRh in the different stages--encoding, consolidation, and retrieval--of object recognition memory. Specifically, recent work in rats has indicated that neural activity in PRh contributes to object memory encoding, consolidation, and retrieval processes. Finally, we consider the pharmacological, cellular, and molecular factors that might play a part in PRh-mediated object recognition memory. Recent studies in rodents have begun to indicate the remarkable complexity of the neural substrates underlying this seemingly simple aspect of declarative memory.

  2. Page Recognition: Quantum Leap In Recognition Technology

    Science.gov (United States)

    Miller, Larry

    1989-07-01

    No milestone has proven as elusive as the always-approaching "year of the LAN," but the "year of the scanner" might claim the silver medal. Desktop scanners have been around almost as long as personal computers. And everyone thinks they are used for obvious desktop-publishing and business tasks like scanning business documents, magazine articles and other pages, and translating those words into files your computer understands. But, until now, the reality fell far short of the promise. Because it's true that scanners deliver an accurate image of the page to your computer, but the software to recognize this text has been woefully disappointing. Old optical-character recognition (OCR) software recognized such a limited range of pages as to be virtually useless to real users. (For example, one OCR vendor specified 12-point Courier font from an IBM Selectric typewriter: the same font in 10-point, or from a Diablo printer, was unrecognizable!) Computer dealers have told me the chasm between OCR expectations and reality is so broad and deep that nine out of ten prospects leave their stores in disgust when they learn the limitations. And this is a very important, very unfortunate gap. Because the promise of recognition -- what people want it to do -- carries with it tremendous improvements in our productivity and ability to get tons of written documents into our computers where we can do real work with it. The good news is that a revolutionary new development effort has led to the new technology of "page recognition," which actually does deliver the promise we've always wanted from OCR. I'm sure every reader appreciates the breakthrough represented by the laser printer and page-makeup software, a combination so powerful it created new reasons for buying a computer. A similar breakthrough is happening right now in page recognition: the Macintosh (and, I must admit, other personal computers) equipped with a moderately priced scanner and OmniPage software (from Caere

  3. 2005 Annual Scientific Conference. Program and Abstracts

    International Nuclear Information System (INIS)

    Barborica, Andrei; Bulinski, Mircea; Stefan, Sabina

    2005-01-01

    Every year the Physics Department of the University of Bucharest organizes the 'Annual Scientific Conference' to present the most interesting scientific results, obtained within the department. This scientific session is opened also to the interested physics researchers from other institutes and universities in the country. This scientific event represents a recognition and a continuation of the prestigious tradition of physics research performed within University. The scientific research in the Physics Department is performed in groups and research centers, the terminal year undergraduate students and graduate students being involved in a high extent in the research works. There are 5 research centers with the status of Center of excellence in research. The long-term strategy adopted by the faculty was focused on developing the scientific research in modern topics of theoretical, experimental and applied physics, as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of the environment, physics - computer science. Following this strategy, the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to perform modern and competitive research projects. The Faculty of Physics is a partner in many common research programs with prestigious foreign universities and institutes. The 2005 session covered the following 8 topics: 1. Atmosphere and Earth Science; Environment Protection (21 papers); 2. Atomic and Molecular Physics; Astrophysics (12 papers); 3. Electricity and Biophysics (19 papers); 4. Nuclear and Elementary Particles Physics (17 papers); 5. Optics, Spectroscopy, Plasma and Lasers (19 papers); 6. Polymer Physics (10 papers); 7. Solid State Physics and Materials Science (10 papers); 8. Theoretical Physics and Applied Mathematics Seminar (12 papers)

  4. Application of biomolecular recognition via magnetic nanoparticle in nanobiotechnology

    Science.gov (United States)

    Shen, Wei-Zheng; Cetinel, Sibel; Montemagno, Carlo

    2018-05-01

    The marriage of biomolecular recognition and magnetic nanoparticle creates tremendous opportunities in the development of advanced technology both in academic research and in industrial sectors. In this paper, we review current progress on the magnetic nanoparticle-biomolecule hybrid systems, particularly employing the recognition pairs of DNA-DNA, DNA-protein, protein-protein, and protein-inorganics in several nanobiotechnology application areas, including molecular biology, diagnostics, medical treatment, industrial biocatalysts, and environmental separations.

  5. MOLECULARLY IMPRINTED POLYMER TECHNOLOGY: A ...

    African Journals Online (AJOL)

    dell

    Cross-linking ensures polymer rigidity that “freezes” the 3-D molecular architecture of the binding cavity when the ... molecular technology applications whose potential is still .... recognition element is responsible for the selective ... organic treatments, making them superior ... efficiency with which such materials may be.

  6. Annual report '80

    International Nuclear Information System (INIS)

    1981-01-01

    This document is an annual report from the Foundation for Fundamental Research on Matter (FOM) and the Foundation Institute for Nuclear Physics Research (IKO). The FOM stimulates research in new fields of physics, by the co-ordination of existing research projects and by calling in the help of its institutes and working groups. Furthermore it supports the IKO which has as its task the promotion of fundamental and applied scientific research in the field of nuclear physics and related fields in the Netherlands. The report contains organisational and financial reports and information concerning the personnel. The following FOM institutes/working-communities have submitted separate reports: Nuclear physics, Institute for atomic and molecular physics, Atomic physics, Metals FOM-TNO, Molecular physics, Solid State, Thermonuclear Research and Plasma Physics and High energy physics. Reports are also included from the Special Committee for Theoretical physics, The Special Committee for Technical physics and the Contact Group for technical semi-conductor physics and electronics. Four ''trend articles'' are also included with the following titles: 'Atomic hydrogen as a gas at low temperatures', 'Negative ion beams', 'Turbulence in plasmas' and 'Nuclear structure described by interacting bosons'. (C.F.)

  7. Probabilistic Open Set Recognition

    Science.gov (United States)

    Jain, Lalit Prithviraj

    Real-world tasks in computer vision, pattern recognition and machine learning often touch upon the open set recognition problem: multi-class recognition with incomplete knowledge of the world and many unknown inputs. An obvious way to approach such problems is to develop a recognition system that thresholds probabilities to reject unknown classes. Traditional rejection techniques are not about the unknown; they are about the uncertain boundary and rejection around that boundary. Thus traditional techniques only represent the "known unknowns". However, a proper open set recognition algorithm is needed to reduce the risk from the "unknown unknowns". This dissertation examines this concept and finds existing probabilistic multi-class recognition approaches are ineffective for true open set recognition. We hypothesize the cause is due to weak adhoc assumptions combined with closed-world assumptions made by existing calibration techniques. Intuitively, if we could accurately model just the positive data for any known class without overfitting, we could reject the large set of unknown classes even under this assumption of incomplete class knowledge. For this, we formulate the problem as one of modeling positive training data by invoking statistical extreme value theory (EVT) near the decision boundary of positive data with respect to negative data. We provide a new algorithm called the PI-SVM for estimating the unnormalized posterior probability of class inclusion. This dissertation also introduces a new open set recognition model called Compact Abating Probability (CAP), where the probability of class membership decreases in value (abates) as points move from known data toward open space. We show that CAP models improve open set recognition for multiple algorithms. Leveraging the CAP formulation, we go on to describe the novel Weibull-calibrated SVM (W-SVM) algorithm, which combines the useful properties of statistical EVT for score calibration with one-class and binary

  8. Touchless palmprint recognition systems

    CERN Document Server

    Genovese, Angelo; Scotti, Fabio

    2014-01-01

    This book examines the context, motivation and current status of biometric systems based on the palmprint, with a specific focus on touchless and less-constrained systems. It covers new technologies in this rapidly evolving field and is one of the first comprehensive books on palmprint recognition systems.It discusses the research literature and the most relevant industrial applications of palmprint biometrics, including the low-cost solutions based on webcams. The steps of biometric recognition are described in detail, including acquisition setups, algorithms, and evaluation procedures. Const

  9. [Prosopagnosia and facial expression recognition].

    Science.gov (United States)

    Koyama, Shinichi

    2014-04-01

    This paper reviews clinical neuropsychological studies that have indicated that the recognition of a person's identity and the recognition of facial expressions are processed by different cortical and subcortical areas of the brain. The fusiform gyrus, especially the right fusiform gyrus, plays an important role in the recognition of identity. The superior temporal sulcus, amygdala, and medial frontal cortex play important roles in facial-expression recognition. Both facial recognition and facial-expression recognition are highly intellectual processes that involve several regions of the brain.

  10. Molecularly Imprinted Membranes

    Science.gov (United States)

    Trotta, Francesco; Biasizzo, Miriam; Caldera, Fabrizio

    2012-01-01

    Although the roots of molecularly imprinted polymers lie in the beginning of 1930s in the past century, they have had an exponential growth only 40–50 years later by the works of Wulff and especially by Mosbach. More recently, it was also proved that molecular imprinted membranes (i.e., polymer thin films) that show recognition properties at molecular level of the template molecule are used in their formation. Different procedures and potential application in separation processes and catalysis are reported. The influences of different parameters on the discrimination abilities are also discussed. PMID:24958291

  11. Optical Character Recognition.

    Science.gov (United States)

    Converso, L.; Hocek, S.

    1990-01-01

    This paper describes computer-based optical character recognition (OCR) systems, focusing on their components (the computer, the scanner, the OCR, and the output device); how the systems work; and features to consider in selecting a system. A list of 26 questions to ask to evaluate systems for potential purchase is included. (JDD)

  12. Recognition of fractal graphs

    NARCIS (Netherlands)

    Perepelitsa, VA; Sergienko, [No Value; Kochkarov, AM

    1999-01-01

    Definitions of prefractal and fractal graphs are introduced, and they are used to formulate mathematical models in different fields of knowledge. The topicality of fractal-graph recognition from the point of view, of fundamental improvement in the efficiency of the solution of algorithmic problems

  13. Facial Expression Recognition

    NARCIS (Netherlands)

    Pantic, Maja; Li, S.; Jain, A.

    2009-01-01

    Facial expression recognition is a process performed by humans or computers, which consists of: 1. Locating faces in the scene (e.g., in an image; this step is also referred to as face detection), 2. Extracting facial features from the detected face region (e.g., detecting the shape of facial

  14. Galeotti on recognition as inclusion

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2008-01-01

    Anna Elisabetta Galeotti's theory of 'toleration as recognition' has been criticised by Peter Jones for being conceptually incoherent, since liberal toleration presupposes a negative attitude to differences, whereas multicultural recognition requires positive affirmation hereof. The paper spells ...

  15. School IPM Recognition and Certification

    Science.gov (United States)

    Schools and school districts can get support and recognition for implementation of school IPM. EPA is developing a program to provide recognition for school districts that are working towards or have achieved a level of success with school IPM programs.

  16. Stereotype Associations and Emotion Recognition

    NARCIS (Netherlands)

    Bijlstra, Gijsbert; Holland, Rob W.; Dotsch, Ron; Hugenberg, Kurt; Wigboldus, Daniel H. J.

    We investigated whether stereotype associations between specific emotional expressions and social categories underlie stereotypic emotion recognition biases. Across two studies, we replicated previously documented stereotype biases in emotion recognition using both dynamic (Study 1) and static

  17. Administrative Circular No. 26 (Rev. 9) – Recognition of Merit

    CERN Multimedia

    2012-01-01

    Administrative Circular No. 26 (Rev. 9) entitled "Recognition of Merit”, approved by the Director-General following discussion in the Standing Concertation Committee meeting on 27 September 2011 is available on the intranet site of the Human Resources Department: https://cern.ch/hr-docs/admincirc/admincirc.asp The circular was above all revised in order to integrate the new CERN Competency Model into the annual procedure of performance appraisal. It cancels and replaces Administrative Circular No. 26 (Rev. 8) entitled "Recognition of merit” of September 2008. Department Head Office HR Department

  18. A REVIEW: OPTICAL CHARACTER RECOGNITION

    OpenAIRE

    Swati Tomar*1 & Amit Kishore2

    2018-01-01

    This paper presents detailed review in the field of Optical Character Recognition. Various techniques are determine that have been proposed to realize the center of character recognition in an optical character recognition system. Even though, sufficient studies and papers are describes the techniques for converting textual content from a paper document into machine readable form. Optical character recognition is a process where the computer understands automatically the image of handwritten ...

  19. Molecular profiling of childhood cancer: Biomarkers and novel therapies

    Directory of Open Access Journals (Sweden)

    Federica Saletta

    2014-06-01

    General significance: The increasing recognition of the heterogeneity of molecular causes of cancer favors the continued development of molecularly targeted agents, and their transfer to pediatric and adolescent populations.

  20. Superficial Priming in Episodic Recognition

    Science.gov (United States)

    Dopkins, Stephen; Sargent, Jesse; Ngo, Catherine T.

    2010-01-01

    We explored the effect of superficial priming in episodic recognition and found it to be different from the effect of semantic priming in episodic recognition. Participants made recognition judgments to pairs of items, with each pair consisting of a prime item and a test item. Correct positive responses to the test item were impeded if the prime…

  1. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  2. Visual Recognition Memory across Contexts

    Science.gov (United States)

    Jones, Emily J. H.; Pascalis, Olivier; Eacott, Madeline J.; Herbert, Jane S.

    2011-01-01

    In two experiments, we investigated the development of representational flexibility in visual recognition memory during infancy using the Visual Paired Comparison (VPC) task. In Experiment 1, 6- and 9-month-old infants exhibited recognition when familiarization and test occurred in the same room, but showed no evidence of recognition when…

  3. Forensic Face Recognition: A Survey

    NARCIS (Netherlands)

    Ali, Tauseef; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; Quaglia, Adamo; Epifano, Calogera M.

    2012-01-01

    The improvements of automatic face recognition during the last 2 decades have disclosed new applications like border control and camera surveillance. A new application field is forensic face recognition. Traditionally, face recognition by human experts has been used in forensics, but now there is a

  4. Semantic Activity Recognition

    OpenAIRE

    Thonnat , Monique

    2008-01-01

    International audience; Extracting automatically the semantics from visual data is a real challenge. We describe in this paper how recent work in cognitive vision leads to significative results in activity recognition for visualsurveillance and video monitoring. In particular we present work performed in the domain of video understanding in our PULSAR team at INRIA in Sophia Antipolis. Our main objective is to analyse in real-time video streams captured by static video cameras and to recogniz...

  5. Student award for outstanding research winner in the Ph.D. category for the 2017 society for biomaterials annual meeting and exposition, april 5-8, 2017, Minneapolis, Minnesota: Characterization of protein interactions with molecularly imprinted hydrogels that possess engineered affinity for high isoelectric point biomarkers.

    Science.gov (United States)

    Clegg, John R; Zhong, Justin X; Irani, Afshan S; Gu, Joann; Spencer, David S; Peppas, Nicholas A

    2017-06-01

    Molecularly imprinted polymers (MIPs) with selective affinity for protein biomarkers could find extensive utility as environmentally robust, cost-efficient biomaterials for diagnostic and therapeutic applications. In order to develop recognitive, synthetic biomaterials for prohibitively expensive protein biomarkers, we have developed a molecular imprinting technique that utilizes structurally similar, analogue proteins. Hydrogel microparticles synthesized by molecular imprinting with trypsin, lysozyme, and cytochrome c possessed an increased affinity for alternate high isoelectric point biomarkers both in isolation and plasma-mimicking adsorption conditions. Imprinted and non-imprinted P(MAA-co-AAm-co-DEAEMA) microgels containing PMAO-PEGMA functionalized polycaprolactone nanoparticles were net-anionic, polydisperse, and irregularly shaped. MIPs and control non-imprinted polymers (NIPs) exhibited regions of Freundlich and BET isotherm adsorption behavior in a range of non-competitive protein solutions, where MIPs exhibited enhanced adsorption capacity in the Freundlich isotherm regions. In a competitive condition, imprinting with analogue templates (trypsin, lysozyme) increased the adsorption capacity of microgels for cytochrome c by 162% and 219%, respectively, as compared to a 122% increase provided by traditional bulk imprinting with cytochrome c. Our results suggest that molecular imprinting with analogue protein templates is a viable synthetic strategy for enhancing hydrogel-biomarker affinity and promoting specific protein adsorption behavior in biological fluids. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1565-1574, 2017. © 2017 Wiley Periodicals, Inc.

  6. Pattern Recognition Control Design

    Science.gov (United States)

    Gambone, Elisabeth A.

    2018-01-01

    Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

  7. An automated approach for annual layer counting in ice cores

    DEFF Research Database (Denmark)

    Winstrup, Mai; Svensson, A. M.; Rasmussen, S. O.

    2012-01-01

    A novel method for automated annual layer counting in seasonally-resolved paleoclimate records has been developed. It relies on algorithms from the statistical framework of Hidden Markov Models (HMMs), which originally was developed for use in machine speech-recognition. The strength of the layer...

  8. An automated approach for annual layer counting in ice cores

    DEFF Research Database (Denmark)

    Winstrup, Mai; Svensson, A. M.; Rasmussen, S. O.

    2012-01-01

    A novel method for automated annual layer counting in seasonally-resolved paleoclimate records has been developed. It relies on algorithms from the statistical framework of hidden Markov models (HMMs), which originally was developed for use in machine speech recognition. The strength of the layer...

  9. Molecular immune recognition of botulinum neurotoxin B. The light chain regions that bind human blocking antibodies from toxin-treated cervical dystonia patients. Antigenic structure of the entire BoNT/B molecule.

    Science.gov (United States)

    Atassi, M Zouhair; Jankovic, Joseph; Steward, Lance E; Aoki, K Roger; Dolimbek, Behzod Z

    2012-01-01

    We recently mapped the regions on the heavy (H) chain of botulinum neurotoxin, type B (BoNT/B) recognized by blocking antibodies (Abs) from cervical dystonia (CD) patients who develop immunoresistance during toxin treatment. Since blocking could also be effected by Abs directed against regions on the light (L) chain, we have mapped here the L chain, using the same 30 CD antisera. We synthesized, purified and characterized 32 19-residue L chain peptides that overlapped successively by 5 residues (peptide L32 overlapped with peptide N1 of the H chain by 12 residues). In a given patient, Abs against the L chain seemed less intense than those against H chain. Most sera recognized a limited set of L chain peptides. The levels of Abs against a given region varied with the patient, consistent with immune responses to each epitope being under separate MHC control. The peptides most frequently recognized were: L13, by 30 of 30 antisera (100%); L22, by 23 of 30 (76.67%); L19, by 15 of 30 (50.00%); L26, by 11 of 30 (36.70%); and L14, by 12 of 30 (40.00%). The activity of L14 probably derives from its overlap with L13. The levels of Ab binding decreased in the following order: L13 (residues 169-187), L22 (295-313), L19 (253-271), and L26 (351-369). Peptides L12 (155-173), L18 (239-257), L15 (197-215), L1 (1-19) and L23 (309-327) exhibited very low Ab binding. The remaining peptides had little or no Ab-binding activity. The antigenic regions are analyzed in terms of their three-dimensional locations and the enzyme active site. With the previous localization of the antigenic regions on the BoNT/B H chain, the human Ab recognition of the entire BoNT/B molecule is presented and compared to the recognition of BoNT/A by human blocking Abs. Copyright © 2011. Published by Elsevier GmbH.

  10. Molecularly Imprinted Polymer Technology: A Powerful, Generic ...

    African Journals Online (AJOL)

    Molecularly Imprinted Polymer Technology: A Powerful, Generic, Facile and Cost Effective Alternative for Enantio-recognition and Separation: A Glance at Advances and Applications. ... Tanzania Journal of Science. Journal Home · ABOUT ...

  11. Annual report and accounts 1994

    International Nuclear Information System (INIS)

    1994-01-01

    The document presents the Amersham International Annual Report and Accounts for 1994. This health science company's research program focuses on developments in life science research, nuclear medicine, and industrial quality and safety assurance, and they have particular expertise in the application of radioactivity to labelling and detection at the molecular level. Sales and profits were both at record levels, and four major new products were launched to the health science market place, with increased investment in research and development, as well as commercialization of the new products, clinical trials, sales training and major launch events. Trading internationally has continued to be fruitful. (UK)

  12. Annual report and accounts 1993

    International Nuclear Information System (INIS)

    1993-01-01

    The Annual Report and Accounts for 1993 are presented for the health science company Amersham International. The company's research program focuses on developments in life science research, nuclear medicine and industrial quality and safety assurance, with particular expertise in the application of radioactivity to labelling and detection at the molecular level. A review of the company's financial performance and shareholders' returns is presented. The company's strategies in its worldwide markets is explained, as are the research programmes underpinning present and future sales growth. The three main businesses are also described. (UK)

  13. Threshold models of recognition and the recognition heuristic

    Directory of Open Access Journals (Sweden)

    Edgar Erdfelder

    2011-02-01

    Full Text Available According to the recognition heuristic (RH theory, decisions follow the recognition principle: Given a high validity of the recognition cue, people should prefer recognized choice options compared to unrecognized ones. Assuming that the memory strength of choice options is strongly correlated with both the choice criterion and recognition judgments, the RH is a reasonable strategy that approximates optimal decisions with a minimum of cognitive effort (Davis-Stober, Dana, and Budescu, 2010. However, theories of recognition memory are not generally compatible with this assumption. For example, some threshold models of recognition presume that recognition judgments can arise from two types of cognitive states: (1 certainty states in which judgments are almost perfectly correlated with memory strength and (2 uncertainty states in which recognition judgments reflect guessing rather than differences in memory strength. We report an experiment designed to test the prediction that the RH applies to certainty states only. Our results show that memory states rather than recognition judgments affect use of recognition information in binary decisions.

  14. Structural insights into the recognition of phosphopeptide by the FHA domain of kanadaptin

    DEFF Research Database (Denmark)

    Xu, Qingping; Deller, Marc C; Nielsen, Tine K

    2014-01-01

    with a phosphopeptide mimic derived from a peptide segment from the N-terminus of a symmetry-related molecule as well as a sulfate bound to the structurally conserved phosphothreonine recognition cleft. This structure provides insights into the molecular recognition features utilized by this family of proteins...

  15. Ficolins and FIBCD1: Soluble and membrane bound pattern recognition molecules with acetyl group selectivity

    DEFF Research Database (Denmark)

    Thomsen, Theresa; Schlosser, Anders; Holmskov, Uffe

    2011-01-01

    as pattern recognition molecules. Ficolins are soluble oligomeric proteins composed of trimeric collagen-like regions linked to fibrinogen-related domains (FReDs) that have the ability to sense molecular patterns on both pathogens and apoptotic cell surfaces and activate the complement system. The ficolins......D-containing molecules, and discusses structural resemblance but also diversity in recognition of acetylated ligands....

  16. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  17. Re-thinking employee recognition: understanding employee experiences of recognition

    OpenAIRE

    Smith, Charlotte

    2013-01-01

    Despite widespread acceptance of the importance of employee recognition for both individuals and organisations and evidence of its increasing use in organisations, employee recognition has received relatively little focused attention from academic researchers. Particularly lacking is research exploring the lived experience of employee recognition and the interpretations and meanings which individuals give to these experiences. Drawing on qualitative interviews conducted as part of my PhD rese...

  18. Foreword. Annual report 2003

    International Nuclear Information System (INIS)

    Sujkowski, Z.

    2004-01-01

    Full text: My Foreword to the 2002 Annual Report ended with a handful of best wishes for the year 2003. One of them, rather highly pitched, was addressed to our funding authorities: may their preaching about a ''Knowledge Based Society in Poland'' come true ! There is, unfortunately, little evidence that this preaching is taken seriously by the preachers, even though the time for that in a unifying Europe is high. I hope that this Annual Report bears witness that at least we are doing our bit in this direction. Thus: We have published 203 papers in international journals. Several of them quickly gain international recognition. There was hard competition for our internal awards. The four emerging winners are behind the contributions: on the creation of circular vortices in Bose-Einstein condensates (contribution 8.23), on our share in the NA49 experiment at CERN (contribution 6.4), on our use of solid state nuclear track detectors, SSNTD, in the hostile environment of hot plasma experiments (contribution 5.5) and on some special detectors for positron emission tomography to be applied in hadron therapy (contribution 3.7). We have also contributed to the general education by, e.g., having over 7000 young guests at our Training Department (see Chapter 11 ), taking part in the Science Festival in Warsaw and Lodz, or starting the ''Roland Maze project'' in that city. The project aims at involving a large number of high school pupils in active research concerning extensive air showers at highest energies (contribution 7.6). Very importantly, it has gained approval and financial support of the local authorities in Lodz. Two international meetings were organized by our Institute: the 28 Mazurian Lakes Conference, ''The Atomic Nucleus as a Laboratory for Fundamental Processes'', EPS sponsored, see e.g. CERN Courier 44 (2004), and the ''Conference on Plasma Research and Applications, PLASMA 2003'', biannual gathering of plasma physics its. Our attempts at obtaining EU

  19. The Coding of Biological Information: From Nucleotide Sequence to Protein Recognition

    Science.gov (United States)

    Štambuk, Nikola

    The paper reviews the classic results of Swanson, Dayhoff, Grantham, Blalock and Root-Bernstein, which link genetic code nucleotide patterns to the protein structure, evolution and molecular recognition. Symbolic representation of the binary addresses defining particular nucleotide and amino acid properties is discussed, with consideration of: structure and metric of the code, direct correspondence between amino acid and nucleotide information, and molecular recognition of the interacting protein motifs coded by the complementary DNA and RNA strands.

  20. Human activity recognition and prediction

    CERN Document Server

    2016-01-01

    This book provides a unique view of human activity recognition, especially fine-grained human activity structure learning, human-interaction recognition, RGB-D data based action recognition, temporal decomposition, and causality learning in unconstrained human activity videos. The techniques discussed give readers tools that provide a significant improvement over existing methodologies of video content understanding by taking advantage of activity recognition. It links multiple popular research fields in computer vision, machine learning, human-centered computing, human-computer interaction, image classification, and pattern recognition. In addition, the book includes several key chapters covering multiple emerging topics in the field. Contributed by top experts and practitioners, the chapters present key topics from different angles and blend both methodology and application, composing a solid overview of the human activity recognition techniques. .

  1. [Comparative studies of face recognition].

    Science.gov (United States)

    Kawai, Nobuyuki

    2012-07-01

    Every human being is proficient in face recognition. However, the reason for and the manner in which humans have attained such an ability remain unknown. These questions can be best answered-through comparative studies of face recognition in non-human animals. Studies in both primates and non-primates show that not only primates, but also non-primates possess the ability to extract information from their conspecifics and from human experimenters. Neural specialization for face recognition is shared with mammals in distant taxa, suggesting that face recognition evolved earlier than the emergence of mammals. A recent study indicated that a social insect, the golden paper wasp, can distinguish their conspecific faces, whereas a closely related species, which has a less complex social lifestyle with just one queen ruling a nest of underlings, did not show strong face recognition for their conspecifics. Social complexity and the need to differentiate between one another likely led humans to evolve their face recognition abilities.

  2. Genetic specificity of face recognition.

    Science.gov (United States)

    Shakeshaft, Nicholas G; Plomin, Robert

    2015-10-13

    Specific cognitive abilities in diverse domains are typically found to be highly heritable and substantially correlated with general cognitive ability (g), both phenotypically and genetically. Recent twin studies have found the ability to memorize and recognize faces to be an exception, being similarly heritable but phenotypically substantially uncorrelated both with g and with general object recognition. However, the genetic relationships between face recognition and other abilities (the extent to which they share a common genetic etiology) cannot be determined from phenotypic associations. In this, to our knowledge, first study of the genetic associations between face recognition and other domains, 2,000 18- and 19-year-old United Kingdom twins completed tests assessing their face recognition, object recognition, and general cognitive abilities. Results confirmed the substantial heritability of face recognition (61%), and multivariate genetic analyses found that most of this genetic influence is unique and not shared with other cognitive abilities.

  3. Speech Recognition on Mobile Devices

    DEFF Research Database (Denmark)

    Tan, Zheng-Hua; Lindberg, Børge

    2010-01-01

    in the mobile context covering motivations, challenges, fundamental techniques and applications. Three ASR architectures are introduced: embedded speech recognition, distributed speech recognition and network speech recognition. Their pros and cons and implementation issues are discussed. Applications within......The enthusiasm of deploying automatic speech recognition (ASR) on mobile devices is driven both by remarkable advances in ASR technology and by the demand for efficient user interfaces on such devices as mobile phones and personal digital assistants (PDAs). This chapter presents an overview of ASR...

  4. Markov Models for Handwriting Recognition

    CERN Document Server

    Plotz, Thomas

    2011-01-01

    Since their first inception, automatic reading systems have evolved substantially, yet the recognition of handwriting remains an open research problem due to its substantial variation in appearance. With the introduction of Markovian models to the field, a promising modeling and recognition paradigm was established for automatic handwriting recognition. However, no standard procedures for building Markov model-based recognizers have yet been established. This text provides a comprehensive overview of the application of Markov models in the field of handwriting recognition, covering both hidden

  5. Sudden Event Recognition: A Survey

    Directory of Open Access Journals (Sweden)

    Mohd Asyraf Zulkifley

    2013-08-01

    Full Text Available Event recognition is one of the most active research areas in video surveillance fields. Advancement in event recognition systems mainly aims to provide convenience, safety and an efficient lifestyle for humanity. A precise, accurate and robust approach is necessary to enable event recognition systems to respond to sudden changes in various uncontrolled environments, such as the case of an emergency, physical threat and a fire or bomb alert. The performance of sudden event recognition systems depends heavily on the accuracy of low level processing, like detection, recognition, tracking and machine learning algorithms. This survey aims to detect and characterize a sudden event, which is a subset of an abnormal event in several video surveillance applications. This paper discusses the following in detail: (1 the importance of a sudden event over a general anomalous event; (2 frameworks used in sudden event recognition; (3 the requirements and comparative studies of a sudden event recognition system and (4 various decision-making approaches for sudden event recognition. The advantages and drawbacks of using 3D images from multiple cameras for real-time application are also discussed. The paper concludes with suggestions for future research directions in sudden event recognition.

  6. 2004 Annual Scientific Conference. Program and Abstracts

    International Nuclear Information System (INIS)

    Barborica, Andrei; Bulinski, Mircea; Stefan, Sabina

    2005-01-01

    As consequence of a long experience in educational as well as research field the Physics Department of the Bucharest University is offering high-standard undergraduate and graduate programs of higher education in physical sciences. The long-term strategy adopted by the faculty was focused on developing scientific research in modern topics of theoretical, experimental and applied physics as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of environment, physics-computer science. Following this strategy the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to approach modern and competitive research projects. Every year the Physics Department of the University of Bucharest organizes the 'Annual Scientific Conference' to present the most interesting scientific results, obtained within the department. This 2004 scientific session is opened also to the interested physics researchers from other institutes and universities in the country. This scientific event represents a recognition and a continuation of the prestigious tradition of physics research performed within University. The scientific research in the Physics Department is performed in groups and research centers, the terminal year undergraduate students and graduate students being involved in a high extent in the research works. There are 5 research centers with the status of Center of excellence in research. The long-term strategy adopted by the faculty was focused on developing the scientific research in modern topics of theoretical, experimental and applied physics, as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of the environment, physics - computer science. Following this strategy, the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to perform modern

  7. 2003 Annual Scientific Conference. Program and Abstracts

    International Nuclear Information System (INIS)

    Barborica, Andrei; Bulinski, Mircea

    2003-01-01

    As consequence of a long experience in educational as well as research field the Physics Department of the Bucharest University is offering high-standard undergraduate and graduate programs of higher education in physical sciences. The long-term strategy adopted by the faculty was focused on developing scientific research in modern topics of theoretical, experimental and applied physics as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of environment, physics-computer science. Following this strategy the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to approach modern and competitive research projects. Every year the Physics Department of the University of Bucharest organizes the 'Annual Scientific Conference' to present the most interesting scientific results, obtained within the department. This scientific session is opened also to the interested physics researchers from other institutes and universities in the country. This scientific event represents a recognition and a continuation of the prestigious tradition of physics research performed within University. The scientific research in the Physics Department is performed in groups and research centers, the terminal year undergraduate students and graduate students being involved in a high extent in the research works. There are 5 research centers with the status of Center of excellence in research. The long-term strategy adopted by the faculty was focused on developing the scientific research in modern topics of theoretical, experimental and applied physics, as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of the environment, physics - computer science. Following this strategy, the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to perform modern and

  8. 2002 Annual Scientific Conference. Program and Abstracts

    International Nuclear Information System (INIS)

    Barborica, Andrei; Bulinski, Mircea; Dinca, Mihai P.

    2002-01-01

    As consequence of a long experience in educational as well as research field the Physics Department of the Bucharest University is offering high-standard undergraduate and graduate programs of higher education in physical sciences. The long-term strategy adopted by the faculty was focused on developing scientific research in modern topics of theoretical, experimental and applied physics as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of environment, physics-computer science. Following this strategy the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to approach modern and competitive research projects. Every year the Physics Department of the University of Bucharest organizes the 'Annual Scientific Conference' to present the most interesting scientific results, obtained within the department. This scientific session is opened also to the interested physics researchers from other institutes and universities in the country. This scientific event represents a recognition and a continuation of the prestigious tradition of physics research performed within University. The scientific research in the Physics Department is performed in groups and research centers, the terminal year undergraduate students and graduate students being involved in a high extent in the research works. There are 5 research centers with the status of Center of excellence in research. The long-term strategy adopted by the faculty was focused on developing the scientific research in modern topics of theoretical, experimental and applied physics, as well as in inter-disciplinary fields as biophysics, medical physics, physics and protection of the environment, physics - computer science. Following this strategy, the Faculty of Physics has diversified the research activity, developing new research laboratories and encouraging the academic community to perform modern and

  9. Piezoelectric sensors based on molecular imprinted polymers for detection of low molecular mass analytes.

    Science.gov (United States)

    Uludağ, Yildiz; Piletsky, Sergey A; Turner, Anthony P F; Cooper, Matthew A

    2007-11-01

    Biomimetic recognition elements employed for the detection of analytes are commonly based on proteinaceous affibodies, immunoglobulins, single-chain and single-domain antibody fragments or aptamers. The alternative supra-molecular approach using a molecularly imprinted polymer now has proven utility in numerous applications ranging from liquid chromatography to bioassays. Despite inherent advantages compared with biochemical/biological recognition (which include robustness, storage endurance and lower costs) there are few contributions that describe quantitative analytical applications of molecularly imprinted polymers for relevant small molecular mass compounds in real-world samples. There is, however, significant literature describing the use of low-power, portable piezoelectric transducers to detect analytes in environmental monitoring and other application areas. Here we review the combination of molecularly imprinted polymers as recognition elements with piezoelectric biosensors for quantitative detection of small molecules. Analytes are classified by type and sample matrix presentation and various molecularly imprinted polymer synthetic fabrication strategies are also reviewed.

  10. Annual report 1973

    International Nuclear Information System (INIS)

    1973-01-01

    The GKSS scientific annual report summarizes the problems and results of the research and development projects of 1973. In contrast to earlier annual reports, a comprehensive description of the research facilities is not included. The annual report was extended by the paragraph 'Financial Report 1973' in the chapter 'Development of Geesthacht Research Centre'. The financial report gives a survey of the financial transactions and the major operations of the year under review. (orig./AK) [de

  11. NUKEM annual report 1981

    International Nuclear Information System (INIS)

    The annual report of this important undertaking in the German nuclear industry informs about its structure, holdings and activities in 1981. The report of the management is followed by remarks on the annual statement of accounts (annual balance, profit-loss accounting) and the report of the Supervisory Board. In the annex the annual balance of NUKEM GmbH/HOBEG mbH as per December 31, 1981, and the profit-loss accounting of NUKEM GmbH/HOBEG mbH for the business year 1981 are presented. (UA) [de

  12. Annual Statistical Supplement, 2002

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2002 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  13. Annual Statistical Supplement, 2010

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2010 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  14. Annual Statistical Supplement, 2007

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2007 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  15. Annual Statistical Supplement, 2001

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2001 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  16. Annual Statistical Supplement, 2016

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2016 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  17. Annual Statistical Supplement, 2011

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2011 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  18. Annual Statistical Supplement, 2005

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2005 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  19. Annual Statistical Supplement, 2015

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2015 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  20. Annual Statistical Supplement, 2003

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2003 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  1. Annual Statistical Supplement, 2017

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2017 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  2. Annual Statistical Supplement, 2008

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2008 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  3. Annual Statistical Supplement, 2014

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2014 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  4. Annual Statistical Supplement, 2004

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2004 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  5. Annual Statistical Supplement, 2000

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2000 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  6. Annual Statistical Supplement, 2009

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2009 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  7. Annual Statistical Supplement, 2006

    Data.gov (United States)

    Social Security Administration — The Annual Statistical Supplement, 2006 includes the most comprehensive data available on the Social Security and Supplemental Security Income programs. More than...

  8. SAR: Stroke Authorship Recognition

    KAUST Repository

    Shaheen, Sara; Rockwood, Alyn; Ghanem, Bernard

    2015-01-01

    Are simple strokes unique to the artist or designer who renders them? If so, can this idea be used to identify authorship or to classify artistic drawings? Also, could training methods be devised to develop particular styles? To answer these questions, we propose the Stroke Authorship Recognition (SAR) approach, a novel method that distinguishes the authorship of 2D digitized drawings. SAR converts a drawing into a histogram of stroke attributes that is discriminative of authorship. We provide extensive classification experiments on a large variety of data sets, which validate SAR's ability to distinguish unique authorship of artists and designers. We also demonstrate the usefulness of SAR in several applications including the detection of fraudulent sketches, the training and monitoring of artists in learning a particular new style and the first quantitative way to measure the quality of automatic sketch synthesis tools. © 2015 The Eurographics Association and John Wiley & Sons Ltd.

  9. Iris Recognition Using Wavelet

    Directory of Open Access Journals (Sweden)

    Khaliq Masood

    2013-08-01

    Full Text Available Biometric systems are getting more attention in the present era. Iris recognition is one of the most secure and authentic among the other biometrics and this field demands more authentic, reliable and fast algorithms to implement these biometric systems in real time. In this paper, an efficient localization technique is presented to identify pupil and iris boundaries using histogram of the iris image. Two small portions of iris have been used for polar transformation to reduce computational time and to increase the efficiency of the system. Wavelet transform is used for feature vector generation. Rotation of iris is compensated without shifts in the iris code. System is tested on Multimedia University Iris Database and results show that proposed system has encouraging performance.

  10. SAR: Stroke Authorship Recognition

    KAUST Repository

    Shaheen, Sara

    2015-10-15

    Are simple strokes unique to the artist or designer who renders them? If so, can this idea be used to identify authorship or to classify artistic drawings? Also, could training methods be devised to develop particular styles? To answer these questions, we propose the Stroke Authorship Recognition (SAR) approach, a novel method that distinguishes the authorship of 2D digitized drawings. SAR converts a drawing into a histogram of stroke attributes that is discriminative of authorship. We provide extensive classification experiments on a large variety of data sets, which validate SAR\\'s ability to distinguish unique authorship of artists and designers. We also demonstrate the usefulness of SAR in several applications including the detection of fraudulent sketches, the training and monitoring of artists in learning a particular new style and the first quantitative way to measure the quality of automatic sketch synthesis tools. © 2015 The Eurographics Association and John Wiley & Sons Ltd.

  11. The Legal Recognition of Sign Languages

    Science.gov (United States)

    De Meulder, Maartje

    2015-01-01

    This article provides an analytical overview of the different types of explicit legal recognition of sign languages. Five categories are distinguished: constitutional recognition, recognition by means of general language legislation, recognition by means of a sign language law or act, recognition by means of a sign language law or act including…

  12. Synergy of Two Highly Specific Biomolecular Recognition Events

    DEFF Research Database (Denmark)

    Ejlersen, Maria; Christensen, Niels Johan; Sørensen, Kasper K

    2018-01-01

    Two highly specific biomolecular recognition events, nucleic acid duplex hybridization and DNA-peptide recognition in the minor groove, were coalesced in a miniature ensemble for the first time by covalently attaching a natural AT-hook peptide motif to nucleic acid duplexes via a 2'-amino......-LNA scaffold. A combination of molecular dynamics simulations and ultraviolet thermal denaturation studies revealed high sequence-specific affinity of the peptide-oligonucleotide conjugates (POCs) when binding to complementary DNA strands, leveraging the bioinformation encrypted in the minor groove of DNA...

  13. Unequal recognition, misrecognition and injustice

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2012-01-01

    by the state of religious minorities. It argues that state–religion relations can be analysed as relations of recognition, which are not only unequal but also multi-dimensional, and that it is difficult to answer the question whether multi-dimensional recognitive inequalities are unjust or wrong if one...

  14. Side-View Face Recognition

    NARCIS (Netherlands)

    Santemiz, P.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; van den Biggelaar, Olivier

    As a widely used biometrics, face recognition has many advantages such as being non-intrusive, natural and passive. On the other hand, in real-life scenarios with uncontrolled environment, pose variation up to side-view positions makes face recognition a challenging work. In this paper we discuss

  15. Infants' Recognition Memory for Hue

    Science.gov (United States)

    Bornstein, Marc H.

    1976-01-01

    Fifty 4-month-old infants were habituated to one wavelength of light and then tested for recognition with the original and two new spectral lights. After short- and long-term delays with different types of retroactive interference, the results indicated that the infants' recognition memory for hue was quite resilient to interference or delay. (JMB)

  16. Forensic Face Recognition: A Survey

    NARCIS (Netherlands)

    Ali, Tauseef; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

    2010-01-01

    Beside a few papers which focus on the forensic aspects of automatic face recognition, there is not much published about it in contrast to the literature on developing new techniques and methodologies for biometric face recognition. In this report, we review forensic facial identification which is

  17. Side-View Face Recognition

    NARCIS (Netherlands)

    Santemiz, P.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2010-01-01

    Side-view face recognition is a challenging problem with many applications. Especially in real-life scenarios where the environment is uncontrolled, coping with pose variations up to side-view positions is an important task for face recognition. In this paper we discuss the use of side view face

  18. FILTWAM and Voice Emotion Recognition

    NARCIS (Netherlands)

    Bahreini, Kiavash; Nadolski, Rob; Westera, Wim

    2014-01-01

    This paper introduces the voice emotion recognition part of our framework for improving learning through webcams and microphones (FILTWAM). This framework enables multimodal emotion recognition of learners during game-based learning. The main goal of this study is to validate the use of microphone

  19. Imprinting of molecular recognition sites combined with π-donor-acceptor interactions using bis-aniline-crosslinked Au-CdSe/ZnS nanoparticles array on electrodes: Development of electrochemiluminescence sensor for the ultrasensitive and selective detection of 2-methyl-4-chlorophenoxyacetic acid.

    Science.gov (United States)

    Yang, Yukun; Fang, Guozhen; Wang, Xiaomin; Liu, Guiyang; Wang, Shuo

    2016-03-15

    A novel strategy is reported for the fabrication of bis-aniline-crosslinked Au nanoparticles (NPs)-CdSe/ZnS quantum dots (QDs) array composite by facil one-step co-electropolymerization of thioaniline-functionalized AuNPs and thioaniline-functionalized CdSe/ZnS QDs onto thioaniline-functionalized Au elctrodes (AuE). Stable and enhanced cathodic electrochemiluminescence (ECL) of CdSe/ZnS QDs is observed on the modified electrode in neutral solution, suggesting promising applications in ECL sensing. An advanced ECL sensor is explored for detection of 2-methyl-4-chlorophenoxyacetic acid (MCPA) which quenches the ECL signal through electron-transfer pathway. The sensitive determination of MCPA with limit of detection (LOD) of 2.2 nmolL(-1) (S/N=3) is achieved by π-donor-acceptor interactions between MCPA and the bis-aniline bridging units. Impressively, the imprinting of molecular recognition sites into the bis-aniline-crosslinked AuNPs-CdSe/ZnS QDs array yields a functionalized electrode with an extremely sensitive response to MCPA in a linear range of 10 pmolL(-1)-50 μmolL(-1) with a LOD of 4.3 pmolL(-1 ()S/N=3). The proposed ECL sensor with high sensitivity, good selectivity, reproducibility and stability has been successfully applied for the determination of MCPA in real samples with satisfactory recoveries. In this study, ECL sensor combined the merits of QDs-ECL and molecularly imprinting technology is reported for the first time. The developed ECL sensor holds great promise for the fabrication of QDs-based ECL sensors with improved sensitivity and furthermore opens the door to wide applications of QDs-based ECL in food safety and environmental monitoring. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. CERN's Merit Appraisal and Recognition System from the point of view of the supervisor

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    The required training consists of 2 parts : This presentation explaining “CERN’s merit recognition system”, followed by a session of questions/answers – duration : 2 hours A training session on “How to get, as a supervisor, the most out of the annual interview” – duration : 1 day. This hands-on training focuses on how to set smart work and development objectives, how to give feedback and how to run the annual interview in a constructive way.

  1. Online handwritten mathematical expression recognition

    Science.gov (United States)

    Büyükbayrak, Hakan; Yanikoglu, Berrin; Erçil, Aytül

    2007-01-01

    We describe a system for recognizing online, handwritten mathematical expressions. The system is designed with a user-interface for writing scientific articles, supporting the recognition of basic mathematical expressions as well as integrals, summations, matrices etc. A feed-forward neural network recognizes symbols which are assumed to be single-stroke and a recursive algorithm parses the expression by combining neural network output and the structure of the expression. Preliminary results show that writer-dependent recognition rates are very high (99.8%) while writer-independent symbol recognition rates are lower (75%). The interface associated with the proposed system integrates the built-in recognition capabilities of the Microsoft's Tablet PC API for recognizing textual input and supports conversion of hand-drawn figures into PNG format. This enables the user to enter text, mathematics and draw figures in a single interface. After recognition, all output is combined into one LATEX code and compiled into a PDF file.

  2. Viewpoint Manifolds for Action Recognition

    Directory of Open Access Journals (Sweden)

    Souvenir Richard

    2009-01-01

    Full Text Available Abstract Action recognition from video is a problem that has many important applications to human motion analysis. In real-world settings, the viewpoint of the camera cannot always be fixed relative to the subject, so view-invariant action recognition methods are needed. Previous view-invariant methods use multiple cameras in both the training and testing phases of action recognition or require storing many examples of a single action from multiple viewpoints. In this paper, we present a framework for learning a compact representation of primitive actions (e.g., walk, punch, kick, sit that can be used for video obtained from a single camera for simultaneous action recognition and viewpoint estimation. Using our method, which models the low-dimensional structure of these actions relative to viewpoint, we show recognition rates on a publicly available dataset previously only achieved using multiple simultaneous views.

  3. CSIR Annual report 1965

    CSIR Research Space (South Africa)

    CSIR

    1965-01-01

    Full Text Available stream_source_info Annual Report_ 1965.pdf.txt stream_content_type text/plain stream_size 48 Content-Encoding ISO-8859-1 stream_name Annual Report_ 1965.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  4. CSIR Annual report 1992

    CSIR Research Space (South Africa)

    CSIR

    1992-01-01

    Full Text Available stream_source_info Annual Report_ 1992.pdf.txt stream_content_type text/plain stream_size 39 Content-Encoding ISO-8859-1 stream_name Annual Report_ 1992.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  5. CSIR Annual report 1979

    CSIR Research Space (South Africa)

    CSIR

    1979-01-01

    Full Text Available stream_source_info CSIR Annual report_1979.pdf.txt stream_content_type text/plain stream_size 86 Content-Encoding ISO-8859-1 stream_name CSIR Annual report_1979.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  6. CSIR Annual report 1976

    CSIR Research Space (South Africa)

    CSIR

    1976-01-01

    Full Text Available stream_source_info Annual Report_1976.pdf.txt stream_content_type text/plain stream_size 75 Content-Encoding ISO-8859-1 stream_name Annual Report_1976.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  7. CSIR Annual report 1978

    CSIR Research Space (South Africa)

    CSIR

    1978-01-01

    Full Text Available stream_source_info Annual Report_1978.pdf.txt stream_content_type text/plain stream_size 78 Content-Encoding ISO-8859-1 stream_name Annual Report_1978.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  8. CSIR Annual report 1991

    CSIR Research Space (South Africa)

    CSIR

    1991-01-01

    Full Text Available stream_source_info Annual Report_ 1991.pdf.txt stream_content_type text/plain stream_size 40 Content-Encoding ISO-8859-1 stream_name Annual Report_ 1991.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  9. Annual Partnership Report, 2016

    Science.gov (United States)

    Wyoming Community College Commission, 2016

    2016-01-01

    The "Annual Partnership Report" catalogs partnerships that Wyoming community colleges established and maintained for each fiscal year. This partnership report fulfills statutory reporting requirement W.S. 21-18-202(e)(iv) which mandates the development of annual reports to the legislature on the outcomes of partnerships between colleges…

  10. Annual Report 1997

    Energy Technology Data Exchange (ETDEWEB)

    Golnik, N.; Mika, J.R.; Wieteska, K. [eds.

    1998-12-31

    This Annual Report of the Institute of Atomic Energy describes the results of the research works carried out at the Institute at 1997. As in the preceding years the authors of the individual scientific reports published in this Annual Report are fully responsible for their content and layout. The Report contains the information on other activities of the Institute as well. (author)

  11. Annual Energy Review, 2008

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-06-01

    The Annual Energy Review (AER) is the Energy Information Administration's (EIA) primary report of annual historical energy statistics. For many series, data begin with the year 1949. Included are statistics on total energy production, consumption, trade, and energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, and international energy; financial and environment indicators; and data unit conversions.

  12. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1993-01-01

    The Natural Gas Annual 1991 provides information on the supply and disposition of natural gas to a wide audience including industry, consumers Federal and State agencies, and education institutions. This report, the Natural Gas Annual 1991 Supplement: Company Profiles, presents a detailed profile of selected companies

  13. Annual Report 2001

    International Nuclear Information System (INIS)

    Swiboda, G.

    2002-01-01

    This Annual Report of the Institute of Atomic Energy describes the results of the research works carried out at the Institute at 2001. As in the preceding years the authors of the individual scientific reports published in this Annual Report are fully responsible for their content and layout. The Report contains the information on other activities of the Institute as well. (author)

  14. Annual report to Congress

    International Nuclear Information System (INIS)

    1987-01-01

    This is the ninth Annual Report to Congress of the United States Department of Energy. It covers the activities of all elements of the Department except the independent Federal Regulatory Commission, which issues its own annual report. 88 refs., 43 tabs

  15. Annual Report 1997

    International Nuclear Information System (INIS)

    Golnik, N.; Mika, J.R.; Wieteska, K.

    1998-01-01

    This Annual Report of the Institute of Atomic Energy describes the results of the research works carried out at the Institute at 1997. As in the preceding years the authors of the individual scientific reports published in this Annual Report are fully responsible for their content and layout. The Report contains the information on other activities of the Institute as well. (author)

  16. Annual Report 1997

    Energy Technology Data Exchange (ETDEWEB)

    Golnik, N; Mika, J R; Wieteska, K [eds.

    1999-12-31

    This Annual Report of the Institute of Atomic Energy describes the results of the research works carried out at the Institute at 1997. As in the preceding years the authors of the individual scientific reports published in this Annual Report are fully responsible for their content and layout. The Report contains the information on other activities of the Institute as well. (author)

  17. Specification for projects of radiogeologic recognition

    International Nuclear Information System (INIS)

    1979-01-01

    This instruction is a guidance to achievement of radiogeologic recognition projects. The radiogeologic recognition is a prospecting method that join the classic geologic recognition with measures of rock radioactivity. (C.M.)

  18. Autonomy, recognition and education

    Directory of Open Access Journals (Sweden)

    Angelo Vitório Cenci

    2015-01-01

    Full Text Available This paper addresses Honneth’s concept of autonomy from two dimensions of his work, distinct, though inseparable. The first one is suggested through the subject’s positive practical self-relation linked to the patterns of reciprocal recognition of love, right and social esteem; the second is formulated as non-centered autonomy opposed to the present-day criticism of the modern autonomous subject encompassing three levels, namely: the capacity of linguistic articulation, the narrative coherence of life and the complementation of being guided by principles with some criteria of moral sensitivity to the context. We defend the position that, by metaphysically anchoring the concept of autonomy onto the intersubjective assumptions of his/her theory of the subject, and exploring it linked to the subject’s positive practical self-relation and to a non-centered meaning, Honneth has managed to renew it, which allows drawing important consequences of such effort to the field of education.

  19. Pattern recognition in spectra

    International Nuclear Information System (INIS)

    Gebran, M; Paletou, F

    2017-01-01

    We present a new automated procedure that simultaneously derives the effective temperature T eff , surface gravity log g , metallicity [ Fe/H ], and equatorial projected rotational velocity v e sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones. (paper)

  20. Vision-Based Navigation and Recognition

    National Research Council Canada - National Science Library

    Rosenfeld, Azriel

    1998-01-01

    .... (4) Invariants: both geometric and other types. (5) Human faces: Analysis of images of human faces, including feature extraction, face recognition, compression, and recognition of facial expressions...

  1. Vision-Based Navigation and Recognition

    National Research Council Canada - National Science Library

    Rosenfeld, Azriel

    1996-01-01

    .... (4) Invariants -- both geometric and other types. (5) Human faces: Analysis of images of human faces, including feature extraction, face recognition, compression, and recognition of facial expressions...

  2. Recognition Using Classification and Segmentation Scoring

    National Research Council Canada - National Science Library

    Kimball, Owen; Ostendorf, Mari; Rohlicek, Robin

    1992-01-01

    .... We describe an approach to connected word recognition that allows the use of segmental information through an explicit decomposition of the recognition criterion into classification and segmentation scoring...

  3. Auditory Modeling for Noisy Speech Recognition

    National Research Council Canada - National Science Library

    2000-01-01

    ... digital filtering for noise cancellation which interfaces to speech recognition software. It uses auditory features in speech recognition training, and provides applications to multilingual spoken language translation...

  4. Kernel learning algorithms for face recognition

    CERN Document Server

    Li, Jun-Bao; Pan, Jeng-Shyang

    2013-01-01

    Kernel Learning Algorithms for Face Recognition covers the framework of kernel based face recognition. This book discusses the advanced kernel learning algorithms and its application on face recognition. This book also focuses on the theoretical deviation, the system framework and experiments involving kernel based face recognition. Included within are algorithms of kernel based face recognition, and also the feasibility of the kernel based face recognition method. This book provides researchers in pattern recognition and machine learning area with advanced face recognition methods and its new

  5. Facial recognition in education system

    Science.gov (United States)

    Krithika, L. B.; Venkatesh, K.; Rathore, S.; Kumar, M. Harish

    2017-11-01

    Human beings exploit emotions comprehensively for conveying messages and their resolution. Emotion detection and face recognition can provide an interface between the individuals and technologies. The most successful applications of recognition analysis are recognition of faces. Many different techniques have been used to recognize the facial expressions and emotion detection handle varying poses. In this paper, we approach an efficient method to recognize the facial expressions to track face points and distances. This can automatically identify observer face movements and face expression in image. This can capture different aspects of emotion and facial expressions.

  6. Iris recognition via plenoptic imaging

    Science.gov (United States)

    Santos-Villalobos, Hector J.; Boehnen, Chris Bensing; Bolme, David S.

    2017-11-07

    Iris recognition can be accomplished for a wide variety of eye images by using plenoptic imaging. Using plenoptic technology, it is possible to correct focus after image acquisition. One example technology reconstructs images having different focus depths and stitches them together, resulting in a fully focused image, even in an off-angle gaze scenario. Another example technology determines three-dimensional data for an eye and incorporates it into an eye model used for iris recognition processing. Another example technology detects contact lenses. Application of the technologies can result in improved iris recognition under a wide variety of scenarios.

  7. Face Recognition using Approximate Arithmetic

    DEFF Research Database (Denmark)

    Marso, Karol

    Face recognition is image processing technique which aims to identify human faces and found its use in various different fields for example in security. Throughout the years this field evolved and there are many approaches and many different algorithms which aim to make the face recognition as effective...... processing applications the results do not need to be completely precise and use of the approximate arithmetic can lead to reduction in terms of delay, space and power consumption. In this paper we examine possible use of approximate arithmetic in face recognition using Eigenfaces algorithm....

  8. Evaluating music emotion recognition:Lessons from music genre recognition?

    OpenAIRE

    Sturm, Bob L.

    2013-01-01

    A fundamental problem with nearly all work in music genre recognition (MGR)is that evaluation lacks validity with respect to the principal goals of MGR. This problem also occurs in the evaluation of music emotion recognition (MER). Standard approaches to evaluation, though easy to implement, do not reliably differentiate between recognizing genre or emotion from music, or by virtue of confounding factors in signals (e.g., equalization). We demonstrate such problems for evaluating an MER syste...

  9. Epstein-Barr virus-positive gastric cancer: a distinct molecular subtype of the disease?

    Science.gov (United States)

    Jácome, Alexandre Andrade Dos Anjos; Lima, Enaldo Melo de; Kazzi, Ana Izabela; Chaves, Gabriela Freitas; Mendonça, Diego Cavalheiro de; Maciel, Marina Mara; Santos, José Sebastião Dos

    2016-04-01

    Approximately 90% of the world population is infected by Epstein-Barr virus (EBV). Usually, it infects B lymphocytes, predisposing them to malignant transformation. Infection of epithelial cells occurs rarely, and it is estimated that about to 10% of gastric cancer patients harbor EBV in their malignant cells. Given that gastric cancer is the third leading cause of cancer-related mortality worldwide, with a global annual incidence of over 950,000 cases, EBV-positive gastric cancer is the largest group of EBV-associated malignancies. Based on gene expression profile studies, gastric cancer was recently categorized into four subtypes; EBV-positive, microsatellite unstable, genomically stable and chromosomal instability. Together with previous studies, this report provided a more detailed molecular characterization of gastric cancer, demonstrating that EBV-positive gastric cancer is a distinct molecular subtype of the disease, with unique genetic and epigenetic abnormalities, reflected in a specific phenotype. The recognition of characteristic molecular alterations in gastric cancer allows the identification of molecular pathways involved in cell proliferation and survival, with the potential to identify therapeutic targets. These findings highlight the enormous heterogeneity of gastric cancer, and the complex interplay between genetic and epigenetic alterations in the disease, and provide a roadmap to implementation of genome-guided personalized therapy in gastric cancer. The present review discusses the initial studies describing EBV-positive gastric cancer as a distinct clinical entity, presents recently described genetic and epigenetic alterations, and considers potential therapeutic insights derived from the recognition of this new molecular subtype of gastric adenocarcinoma.

  10. Indoor navigation by image recognition

    Science.gov (United States)

    Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man

    2017-07-01

    With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.

  11. Pattern recognition and string matching

    CERN Document Server

    Cheng, Xiuzhen

    2002-01-01

    The research and development of pattern recognition have proven to be of importance in science, technology, and human activity. Many useful concepts and tools from different disciplines have been employed in pattern recognition. Among them is string matching, which receives much theoretical and practical attention. String matching is also an important topic in combinatorial optimization. This book is devoted to recent advances in pattern recognition and string matching. It consists of twenty eight chapters written by different authors, addressing a broad range of topics such as those from classifica­ tion, matching, mining, feature selection, and applications. Each chapter is self-contained, and presents either novel methodological approaches or applications of existing theories and techniques. The aim, intent, and motivation for publishing this book is to pro­ vide a reference tool for the increasing number of readers who depend upon pattern recognition or string matching in some way. This includes student...

  12. License plate recognition (phase B).

    Science.gov (United States)

    2010-06-01

    License Plate Recognition (LPR) technology has been used for off-line automobile enforcement purposes. The technology has seen mixed success with correct reading rate as high as 60 to 80% depending on the specific application and environment. This li...

  13. Similarity measures for face recognition

    CERN Document Server

    Vezzetti, Enrico

    2015-01-01

    Face recognition has several applications, including security, such as (authentication and identification of device users and criminal suspects), and in medicine (corrective surgery and diagnosis). Facial recognition programs rely on algorithms that can compare and compute the similarity between two sets of images. This eBook explains some of the similarity measures used in facial recognition systems in a single volume. Readers will learn about various measures including Minkowski distances, Mahalanobis distances, Hansdorff distances, cosine-based distances, among other methods. The book also summarizes errors that may occur in face recognition methods. Computer scientists "facing face" and looking to select and test different methods of computing similarities will benefit from this book. The book is also useful tool for students undertaking computer vision courses.

  14. NIRE annual report 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The National Institute for Resources and Environment (NIRE) has a R & D concept of 'ecotechnology' that aims to protect the environment from degradation whilst promoting sustainable development. This annual report presents summaries of 32 recent research efforts.

  15. ASIST 2002 annual meeting

    CERN Multimedia

    Peek, R

    2003-01-01

    Review of discussions and presentations at the American Society for Information Science and Technology 2002 annual meeting. Topics covered included new models of scholarly publishing and the development of the semantic web (1 page).

  16. SIS - Annual Catch Limit

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Annual Catch Limit (ACL) dataset within the Species Information System (SIS) contains information and data related to management reference points and catch data.

  17. IKO Annual Report 1976

    International Nuclear Information System (INIS)

    1977-01-01

    The IKO Annual Report of 1976 relates their progress in different projects and project fields. The fields covered include electron scattering, pion and muon physics, theory, radio- and nuclear chemistry, technical department, MEA, nuclear reactions and nuclear spectroscopy

  18. Annual Adjustment Factors

    Data.gov (United States)

    Department of Housing and Urban Development — The Department of Housing and Urban Development establishes the rent adjustment factors - called Annual Adjustment Factors (AAFs) - on the basis of Consumer Price...

  19. 2002 Annual report: synthesis

    International Nuclear Information System (INIS)

    2003-01-01

    This synthesis of the Annual Report 2002 presents information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (ARN) of the Argentina during 2002

  20. Annual report 1980

    International Nuclear Information System (INIS)

    1981-01-01

    This annual report contains a description of the named institute, the research programm, reports from the scientific establishments, a description of different cooperations, and a list of scientific publications. (HSI) [de

  1. Annual Report 1974

    International Nuclear Information System (INIS)

    1975-01-01

    This annual report supersedes the work done in the nuclear physics institute at Lyon. The studied matters are the following: nuclear theory, nuclear reactions, nuclear spectroscopy and nuclear chemistry [fr

  2. 2010 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-01-01

    This annual report includes: an overview of Western; approaches for future hydropower and transmission service; major achievements in FY 2010; FY 2010 customer Integrated Resource Planning, or IRP, survey; and financial data.

  3. Annual report 1990

    International Nuclear Information System (INIS)

    Gaeggeler, H.W.; Lorenzen, R.

    1991-04-01

    This annual report of the chemistry laboratory gives an overview of research performed during 1990 in the field of geochemistry, trace analysis, aerosol chemistry, heavy elements, cement chemistry and analytical chemistry. figs., tabs., refs

  4. Scientific annual report 1980

    International Nuclear Information System (INIS)

    1981-01-01

    This annual report contains a collection of the abstracts of the publications concerning research and development in the named institute together with a bibliography about further publications, contributions to conferences and speeches. (HSI) [de

  5. Annual report - LNLS - 1990

    International Nuclear Information System (INIS)

    1990-01-01

    This is the 1990 Annual Report of the LNLS, the upcoming Brazilian Synchrotron Light Source. It discusses its projects, organization as well as the proposed experimental stations. It presents also a list of publications. (A.C.A.S.)

  6. Annual report 2005

    International Nuclear Information System (INIS)

    Toncik, M.

    2006-04-01

    In this Annual report the operating of the Slovak Environmental Agency in 2005 is reported. The structure of the Agency, mission, personnel structure, financing, monitoring of the environment, international cooperation and coordination of research programmes are reviewed

  7. Annual report 2002

    International Nuclear Information System (INIS)

    Toncik, M.

    2003-04-01

    In this Annual report the operating of the Slovak Environmental Agency in 2002 is reported. Structure of the Agency, mission, personnel structure, financing, monitoring of the environment, international cooperation and coordination of research programmes are reviewed

  8. Annual report 2004

    International Nuclear Information System (INIS)

    Toncik, M.

    2005-04-01

    In this Annual report the operating of the Slovak Environmental Agency in 2004 is reported. The structure of the Agency, mission, personnel structure, financing, monitoring of the environment, international cooperation and coordination of research programmes are reviewed

  9. Annual report 2003

    International Nuclear Information System (INIS)

    Toncik, M.

    2004-04-01

    In this Annual report the operating of the Slovak Environmental Agency in 2003 is reported. The structure of the Agency, mission, personnel structure, financing, monitoring of the environment, international cooperation and coordination of research programmes are reviewed

  10. Annual report 2006

    International Nuclear Information System (INIS)

    Anon

    2007-04-01

    In this Annual report the operating of the Slovak Environmental Agency in 2006 is reported. The structure of the Agency, mission, personnel structure, financing, monitoring of the environment, international cooperation and coordination of research programmes are reviewed

  11. Annual Report 1978

    International Nuclear Information System (INIS)

    1979-01-01

    The annual report gives the specific scientific results in the fields of nuclear and radiation physics, radiation chemistry, radiochemistry and data processing with a list of publications. (orig.) [de

  12. 2000 Annual report: synthesis

    International Nuclear Information System (INIS)

    2001-01-01

    This synthesis of the Annual Report 2000 present information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (NRA) of the Argentina during 2000

  13. 2001 Annual report: synthesis

    International Nuclear Information System (INIS)

    2001-01-01

    This synthesis of the Annual Report 2001 presents information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (ARN) of the Argentina during 2001

  14. [Neurological disease and facial recognition].

    Science.gov (United States)

    Kawamura, Mitsuru; Sugimoto, Azusa; Kobayakawa, Mutsutaka; Tsuruya, Natsuko

    2012-07-01

    To discuss the neurological basis of facial recognition, we present our case reports of impaired recognition and a review of previous literature. First, we present a case of infarction and discuss prosopagnosia, which has had a large impact on face recognition research. From a study of patient symptoms, we assume that prosopagnosia may be caused by unilateral right occipitotemporal lesion and right cerebral dominance of facial recognition. Further, circumscribed lesion and degenerative disease may also cause progressive prosopagnosia. Apperceptive prosopagnosia is observed in patients with posterior cortical atrophy (PCA), pathologically considered as Alzheimer's disease, and associative prosopagnosia in frontotemporal lobar degeneration (FTLD). Second, we discuss face recognition as part of communication. Patients with Parkinson disease show social cognitive impairments, such as difficulty in facial expression recognition and deficits in theory of mind as detected by the reading the mind in the eyes test. Pathological and functional imaging studies indicate that social cognitive impairment in Parkinson disease is possibly related to damages in the amygdalae and surrounding limbic system. The social cognitive deficits can be observed in the early stages of Parkinson disease, and even in the prodromal stage, for example, patients with rapid eye movement (REM) sleep behavior disorder (RBD) show impairment in facial expression recognition. Further, patients with myotonic dystrophy type 1 (DM 1), which is a multisystem disease that mainly affects the muscles, show social cognitive impairment similar to that of Parkinson disease. Our previous study showed that facial expression recognition impairment of DM 1 patients is associated with lesion in the amygdalae and insulae. Our study results indicate that behaviors and personality traits in DM 1 patients, which are revealed by social cognitive impairment, are attributable to dysfunction of the limbic system.

  15. Annual report 2003

    International Nuclear Information System (INIS)

    2003-01-01

    Delivering products and services to nuclear power plants operators, AREVA operates in every sector of the civilian nuclear power and fuel cycle industry. This annual report 2003 provides, in seven chapters, information on persons responsible for the annual report and for auditing the financial statements, general information on the company and share capital (statute, capital, share trading, dividends), information on company operations, changes and future prospects, assets, financial position and financial performance, corporate governance, recent developments and future prospects. (A.L.B.)

  16. Annual report June 1988

    International Nuclear Information System (INIS)

    1988-01-01

    This annual report reviews the activities of the National Accelerator Centre until June 1988. The 200 MeV cyclotron facility, the Pretoria cyclotron facility and the Van De Graaff facility are discussed in detail. Aspects of the 200 MeV cyclotron facility examined are, inter alia: the injector cyclotrons, the separated-sector cyclotron, the control system, the beam transport system and radioisotope production. Separate abstracts were prepared for the various subdivisions contained in this annual report

  17. Natural gas annual 1995

    International Nuclear Information System (INIS)

    1996-11-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1995 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1991 to 1995 for each Census Division and each State. Annual historical data are shown at the national level

  18. Natural gas annual 1993

    International Nuclear Information System (INIS)

    1994-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1993 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition from 1989 to 1993 are given for each Census Division and each State. Annual historical data are shown at the national level

  19. Natural gas annual 1991

    International Nuclear Information System (INIS)

    1992-01-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1991 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. Tables summarizing natural gas supply and disposition form 1987 to 1991 are given for each Census Division and each State. Annual historical data are shown at the national level

  20. Nanostructured materials for selective recognition and targeted drug delivery

    International Nuclear Information System (INIS)

    Kotrotsiou, O; Kotti, K; Dini, E; Kammona, O; Kiparissides, C

    2005-01-01

    Selective recognition requires the introduction of a molecular memory into a polymer matrix in order to make it capable of rebinding an analyte with a very high specificity. In addition, targeted drug delivery requires drug-loaded vesicles which preferentially localize to the sites of injury and avoid uptake into uninvolved tissues. The rapid evolution of nanotechnology is aiming to fulfill the goal of selective recognition and optimal drug delivery through the development of molecularly imprinted polymeric (MIP) nanoparticles, tailor-made for a diverse range of analytes (e.g., pharmaceuticals, pesticides, amino acids, etc.) and of nanostructured targeted drug carriers (e.g., liposomes and micelles) with increased circulation lifetimes. In the present study, PLGA microparticles containing multilamellar vesicles (MLVs), and MIP nanoparticles were synthesized to be employed as drug carriers and synthetic receptors respectively

  1. International Journal of Molecular Science 2017 Best Paper Award.

    Science.gov (United States)

    2017-11-02

    The Editors of the International Journal of Molecular Sciences have established the Best Paper Award to recognize the most outstanding articles published in the areas of molecular biology, molecular physics and chemistry that have been published in the International Journal of Molecular Sciences. The prizes have been awarded annually since 2012 [...].

  2. Voice congruency facilitates word recognition.

    Directory of Open Access Journals (Sweden)

    Sandra Campeanu

    Full Text Available Behavioral studies of spoken word memory have shown that context congruency facilitates both word and source recognition, though the level at which context exerts its influence remains equivocal. We measured event-related potentials (ERPs while participants performed both types of recognition task with words spoken in four voices. Two voice parameters (i.e., gender and accent varied between speakers, with the possibility that none, one or two of these parameters was congruent between study and test. Results indicated that reinstating the study voice at test facilitated both word and source recognition, compared to similar or no context congruency at test. Behavioral effects were paralleled by two ERP modulations. First, in the word recognition test, the left parietal old/new effect showed a positive deflection reflective of context congruency between study and test words. Namely, the same speaker condition provided the most positive deflection of all correctly identified old words. In the source recognition test, a right frontal positivity was found for the same speaker condition compared to the different speaker conditions, regardless of response success. Taken together, the results of this study suggest that the benefit of context congruency is reflected behaviorally and in ERP modulations traditionally associated with recognition memory.

  3. Voice congruency facilitates word recognition.

    Science.gov (United States)

    Campeanu, Sandra; Craik, Fergus I M; Alain, Claude

    2013-01-01

    Behavioral studies of spoken word memory have shown that context congruency facilitates both word and source recognition, though the level at which context exerts its influence remains equivocal. We measured event-related potentials (ERPs) while participants performed both types of recognition task with words spoken in four voices. Two voice parameters (i.e., gender and accent) varied between speakers, with the possibility that none, one or two of these parameters was congruent between study and test. Results indicated that reinstating the study voice at test facilitated both word and source recognition, compared to similar or no context congruency at test. Behavioral effects were paralleled by two ERP modulations. First, in the word recognition test, the left parietal old/new effect showed a positive deflection reflective of context congruency between study and test words. Namely, the same speaker condition provided the most positive deflection of all correctly identified old words. In the source recognition test, a right frontal positivity was found for the same speaker condition compared to the different speaker conditions, regardless of response success. Taken together, the results of this study suggest that the benefit of context congruency is reflected behaviorally and in ERP modulations traditionally associated with recognition memory.

  4. LIBRA: LIgand Binding site Recognition Application.

    Science.gov (United States)

    Hung, Le Viet; Caprari, Silvia; Bizai, Massimiliano; Toti, Daniele; Polticelli, Fabio

    2015-12-15

    In recent years, structural genomics and ab initio molecular modeling activities are leading to the availability of a large number of structural models of proteins whose biochemical function is not known. The aim of this study was the development of a novel software tool that, given a protein's structural model, predicts the presence and identity of active sites and/or ligand binding sites. The algorithm implemented by ligand binding site recognition application (LIBRA) is based on a graph theory approach to find the largest subset of similar residues between an input protein and a collection of known functional sites. The algorithm makes use of two predefined databases for active sites and ligand binding sites, respectively, derived from the Catalytic Site Atlas and the Protein Data Bank. Tests indicate that LIBRA is able to identify the correct binding/active site in 90% of the cases analyzed, 90% of which feature the identified site as ranking first. As far as ligand binding site recognition is concerned, LIBRA outperforms other structure-based ligand binding sites detection tools with which it has been compared. The application, developed in Java SE 7 with a Swing GUI embedding a JMol applet, can be run on any OS equipped with a suitable Java Virtual Machine (JVM), and is available at the following URL: http://www.computationalbiology.it/software/LIBRAv1.zip. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Colorimetric Recognition of Aldehydes and Ketones.

    Science.gov (United States)

    Li, Zheng; Fang, Ming; LaGasse, Maria K; Askim, Jon R; Suslick, Kenneth S

    2017-08-07

    A colorimetric sensor array has been designed for the identification of and discrimination among aldehydes and ketones in vapor phase. Due to rapid chemical reactions between the solid-state sensor elements and gaseous analytes, distinct color difference patterns were produced and digitally imaged for chemometric analysis. The sensor array was developed from classical spot tests using aniline and phenylhydrazine dyes that enable molecular recognition of a wide variety of aliphatic or aromatic aldehydes and ketones, as demonstrated by hierarchical cluster, principal component, and support vector machine analyses. The aldehyde/ketone-specific sensors were further employed for differentiation among and identification of ten liquor samples (whiskies, brandy, vodka) and ethanol controls, showing its potential applications in the beverage industry. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Molecular Biology and Functions of Carrier Proteins. Annual Symposium (46th) of the Society of General Physiologists held in Woods Hole, Massachusetts on September 10-13, 1992. Volume 48

    Science.gov (United States)

    1993-09-13

    resistance in the enteric protozoan Entamoeba histolytica has been found associated with the overexpression of at least three mdr-related mRNA species...mutants of " Entamoeba histolytica overexpress mRNAs for multidrug resistance. Molecular and Biochemi- cal Parasitology. 38:281-290. Schinkel, A. H., M. E...incubated in 100 Ri of a solution containing 50 l.M NaI25 ( sp act 100 mCi/mmol), 10 mM HEPES (pH 7.5), 1 mM MgCl2. and 2 mM KCI with either 101 mM NaCI

  7. Protein crystals as scanned probes for recognition atomic force microscopy.

    Science.gov (United States)

    Wickremasinghe, Nissanka S; Hafner, Jason H

    2005-12-01

    Lysozyme crystal growth has been localized at the tip of a conventional silicon nitride cantilever through seeded nucleation. After cross-linking with glutaraldehyde, lysozyme protein crystal tips image gold nanoparticles and grating standards with a resolution comparable to that of conventional tips. Force spectra between the lysozyme crystal tips and surfaces covered with antilysozyme reveal an adhesion force that drops significantly upon blocking with free lysozyme, thus confirming that lysozyme crystal tips can detect molecular recognition interactions.

  8. Comparing Face Detection and Recognition Techniques

    OpenAIRE

    Korra, Jyothi

    2016-01-01

    This paper implements and compares different techniques for face detection and recognition. One is find where the face is located in the images that is face detection and second is face recognition that is identifying the person. We study three techniques in this paper: Face detection using self organizing map (SOM), Face recognition by projection and nearest neighbor and Face recognition using SVM.

  9. Chirality in molecular collision dynamics

    Science.gov (United States)

    Lombardi, Andrea; Palazzetti, Federico

    2018-02-01

    Chirality is a phenomenon that permeates the natural world, with implications for atomic and molecular physics, for fundamental forces and for the mechanisms at the origin of the early evolution of life and biomolecular homochirality. The manifestations of chirality in chemistry and biochemistry are numerous, the striking ones being chiral recognition and asymmetric synthesis with important applications in molecular sciences and in industrial and pharmaceutical chemistry. Chiral discrimination phenomena, due to the existence of two enantiomeric forms, very well known in the case of interaction with light, but still nearly disregarded in molecular collision studies. Here we review some ideas and recent advances about the role of chirality in molecular collisions, designing and illustrating molecular beam experiments for the demonstration of chiral effects and suggesting a scenario for a stereo-directional origin of chiral selection.

  10. Structure of the mouse galectin-4 N-terminal carbohydrate-recognition domain reveals the mechanism of oligosaccharide recognition

    Czech Academy of Sciences Publication Activity Database

    Krejčiříková, Veronika; Pachl, Petr; Fábry, Milan; Malý, Petr; Řezáčová, Pavlína; Brynda, Jiří

    2011-01-01

    Roč. 67, Pt3 (2011), 204-211 ISSN 0907-4449 R&D Projects: GA ČR GA203/09/0820; GA ČR GA304/03/0090; GA ČR GA301/07/0600 Institutional research plan: CEZ:AV0Z50520514; CEZ:AV0Z50520701; CEZ:AV0Z40550506 Keywords : S-type lectins * carbohydrate binding * molecular recognition Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 12.619, year: 2011

  11. Molecular recognition of chromophore molecules to amine terminated surfaces

    International Nuclear Information System (INIS)

    Flores-Perez, Rosangelly; Ivanisevic, Albena

    2007-01-01

    We report the design and characterization of quartz surfaces that can bind to three retinal based chromophores. The amine terminated surfaces were engineered in order to mimic the environment of the opsin protein that accommodates binding of chromophore molecules in the human eye. Each surface coupling step was characterized by water contact angle measurements, ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and transmission infrared spectroscopy. The spectroscopic techniques confirmed that the three chromophore molecules can bind to the surface using a Schiff base mode. Our data suggests that the availability of the amine groups on the surface is critical in the accommodation of the binding of different chromophores

  12. Biofluidic Transport and Molecular Recognition in Polymer Microdevices

    National Research Council Canada - National Science Library

    Davis, Robert H; Anseth, Kristi S; Bowman, Christopher N

    2005-01-01

    .... Key accomplishments include specific cell adhesion and cytocompatibility demonstrated with grafted surfaces, a fluid-responsive polymer micropump integrated on a device and characterized, a porous...

  13. [Studies of biologic activation associated with molecular receptor increase and tumor response in ChL6/L6 protocol patients; Studies in phantoms; Quantitative SPECT; Preclinical studies; and Clinical studies]. DOE annual report, 1994-95

    International Nuclear Information System (INIS)

    DeNardo, S.J.

    1995-01-01

    The authors describe results which have not yet been published from their associated studies listed in the title. For the first, they discuss Lym-1 single chain genetically engineered molecules, analysis of molecular genetic coded messages to enhance tumor response, and human dosimetry and therapeutic human use radiopharmaceuticals. Studies in phantoms includes a discussion of planar image quantitation, counts coincidence correction, organ studies, tumor studies, and 90 Y quantitation with Bremsstrahlung imaging. The study on SPECT discusses attenuation correction and scatter correction. Preclinical studies investigated uptake of 90 Y-BrE-3 in mice using autoradiography. Clinical studies discuss image quantitation verses counts from biopsy samples, S factors for radiation dose calculation, 67 Cu imaging studies for lymphoma cancer, and 111 In MoAb imaging studies for breast cancer to predict 90 Y MoAb therapy

  14. Bidirectional Modulation of Recognition Memory.

    Science.gov (United States)

    Ho, Jonathan W; Poeta, Devon L; Jacobson, Tara K; Zolnik, Timothy A; Neske, Garrett T; Connors, Barry W; Burwell, Rebecca D

    2015-09-30

    Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects. For example, animals and humans with perirhinal damage are unable to distinguish familiar from novel objects in recognition memory tasks. In the normal brain, perirhinal neurons respond to novelty and familiarity by increasing or decreasing firing rates. Recent work also implicates oscillatory activity in the low-beta and low-gamma frequency bands in sensory detection, perception, and recognition. Using optogenetic methods in a spontaneous object exploration (SOR) task, we altered recognition memory performance in rats. In the SOR task, normal rats preferentially explore novel images over familiar ones. We modulated exploratory behavior in this task by optically stimulating channelrhodopsin-expressing perirhinal neurons at various frequencies while rats looked at novel or familiar 2D images. Stimulation at 30-40 Hz during looking caused rats to treat a familiar image as if it were novel by increasing time looking at the image. Stimulation at 30-40 Hz was not effective in increasing exploration of novel images. Stimulation at 10-15 Hz caused animals to treat a novel image as familiar by decreasing time looking at the image, but did not affect looking times for images that were already familiar. We conclude that optical stimulation of PER at different frequencies can alter visual recognition memory bidirectionally. Significance statement: Recognition of novelty and familiarity are important for learning, memory, and decision making. Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects, but how novelty and familiarity are encoded and transmitted in the brain is not known. Perirhinal neurons respond to novelty and familiarity by changing firing rates, but recent work suggests that brain oscillations may also be important for recognition. In this study, we showed that stimulation of

  15. Bio-recognitive photonics of a DNA-guided organic semiconductor

    Science.gov (United States)

    Back, Seung Hyuk; Park, Jin Hyuk; Cui, Chunzhi; Ahn, Dong June

    2016-01-01

    Incorporation of duplex DNA with higher molecular weights has attracted attention for a new opportunity towards a better organic light-emitting diode (OLED) capability. However, biological recognition by OLED materials is yet to be addressed. In this study, specific oligomeric DNA-DNA recognition is successfully achieved by tri (8-hydroxyquinoline) aluminium (Alq3), an organic semiconductor. Alq3 rods crystallized with guidance from single-strand DNA molecules show, strikingly, a unique distribution of the DNA molecules with a shape of an `inverted' hourglass. The crystal's luminescent intensity is enhanced by 1.6-fold upon recognition of the perfect-matched target DNA sequence, but not in the case of a single-base mismatched one. The DNA-DNA recognition forming double-helix structure is identified to occur only in the rod's outer periphery. This study opens up new opportunities of Alq3, one of the most widely used OLED materials, enabling biological recognition.

  16. Bio-recognitive photonics of a DNA-guided organic semiconductor.

    Science.gov (United States)

    Back, Seung Hyuk; Park, Jin Hyuk; Cui, Chunzhi; Ahn, Dong June

    2016-01-04

    Incorporation of duplex DNA with higher molecular weights has attracted attention for a new opportunity towards a better organic light-emitting diode (OLED) capability. However, biological recognition by OLED materials is yet to be addressed. In this study, specific oligomeric DNA-DNA recognition is successfully achieved by tri (8-hydroxyquinoline) aluminium (Alq3), an organic semiconductor. Alq3 rods crystallized with guidance from single-strand DNA molecules show, strikingly, a unique distribution of the DNA molecules with a shape of an 'inverted' hourglass. The crystal's luminescent intensity is enhanced by 1.6-fold upon recognition of the perfect-matched target DNA sequence, but not in the case of a single-base mismatched one. The DNA-DNA recognition forming double-helix structure is identified to occur only in the rod's outer periphery. This study opens up new opportunities of Alq3, one of the most widely used OLED materials, enabling biological recognition.

  17. Cognitive object recognition system (CORS)

    Science.gov (United States)

    Raju, Chaitanya; Varadarajan, Karthik Mahesh; Krishnamurthi, Niyant; Xu, Shuli; Biederman, Irving; Kelley, Troy

    2010-04-01

    We have developed a framework, Cognitive Object Recognition System (CORS), inspired by current neurocomputational models and psychophysical research in which multiple recognition algorithms (shape based geometric primitives, 'geons,' and non-geometric feature-based algorithms) are integrated to provide a comprehensive solution to object recognition and landmarking. Objects are defined as a combination of geons, corresponding to their simple parts, and the relations among the parts. However, those objects that are not easily decomposable into geons, such as bushes and trees, are recognized by CORS using "feature-based" algorithms. The unique interaction between these algorithms is a novel approach that combines the effectiveness of both algorithms and takes us closer to a generalized approach to object recognition. CORS allows recognition of objects through a larger range of poses using geometric primitives and performs well under heavy occlusion - about 35% of object surface is sufficient. Furthermore, geon composition of an object allows image understanding and reasoning even with novel objects. With reliable landmarking capability, the system improves vision-based robot navigation in GPS-denied environments. Feasibility of the CORS system was demonstrated with real stereo images captured from a Pioneer robot. The system can currently identify doors, door handles, staircases, trashcans and other relevant landmarks in the indoor environment.

  18. An audiovisual emotion recognition system

    Science.gov (United States)

    Han, Yi; Wang, Guoyin; Yang, Yong; He, Kun

    2007-12-01

    Human emotions could be expressed by many bio-symbols. Speech and facial expression are two of them. They are both regarded as emotional information which is playing an important role in human-computer interaction. Based on our previous studies on emotion recognition, an audiovisual emotion recognition system is developed and represented in this paper. The system is designed for real-time practice, and is guaranteed by some integrated modules. These modules include speech enhancement for eliminating noises, rapid face detection for locating face from background image, example based shape learning for facial feature alignment, and optical flow based tracking algorithm for facial feature tracking. It is known that irrelevant features and high dimensionality of the data can hurt the performance of classifier. Rough set-based feature selection is a good method for dimension reduction. So 13 speech features out of 37 ones and 10 facial features out of 33 ones are selected to represent emotional information, and 52 audiovisual features are selected due to the synchronization when speech and video fused together. The experiment results have demonstrated that this system performs well in real-time practice and has high recognition rate. Our results also show that the work in multimodules fused recognition will become the trend of emotion recognition in the future.

  19. Kazakh Traditional Dance Gesture Recognition

    Science.gov (United States)

    Nussipbekov, A. K.; Amirgaliyev, E. N.; Hahn, Minsoo

    2014-04-01

    Full body gesture recognition is an important and interdisciplinary research field which is widely used in many application spheres including dance gesture recognition. The rapid growth of technology in recent years brought a lot of contribution in this domain. However it is still challenging task. In this paper we implement Kazakh traditional dance gesture recognition. We use Microsoft Kinect camera to obtain human skeleton and depth information. Then we apply tree-structured Bayesian network and Expectation Maximization algorithm with K-means clustering to calculate conditional linear Gaussians for classifying poses. And finally we use Hidden Markov Model to detect dance gestures. Our main contribution is that we extend Kinect skeleton by adding headwear as a new skeleton joint which is calculated from depth image. This novelty allows us to significantly improve the accuracy of head gesture recognition of a dancer which in turn plays considerable role in whole body gesture recognition. Experimental results show the efficiency of the proposed method and that its performance is comparable to the state-of-the-art system performances.

  20. Annual report 1976

    International Nuclear Information System (INIS)

    1977-01-01

    This annual report is the fifth issued in English from the Tandem Accelerator Laboratory in Uppsala since research was started in November 1970. It covers work performed during the calendar year 1976 and updates information given in earlier annual reports with regard to laboratory facilities such as computer configuration and layout of the experimental area. The descriptions of the research projects are also in general more detailed than usual and may sometime contain results obtained before 1976 in order to avoid too many references to earlier annual reports. It has, for instance, been thought of interest to make the sections on the study of beam foil excitation of atoms and on the measurements of nuclear deformations by the REPREC method quite extensive. (Auth.)

  1. Petroleum supply annual 1992

    International Nuclear Information System (INIS)

    1993-01-01

    The Petroleum Supply Annual (PSA) contains information on the supply and disposition of crude oil and petroleum products. The publication reflects data that were collected from the petroleum industry during 1992 through annual and monthly surveys. The PSA is divided into two volumes. The first volume contains four sections: Summary Statistics, Detailed Statistics, Refinery Capacity, and Oxygenate Capacity each with final annual data. This second volume contains final statistics for each month of 1992, and replaces data previously published in the Petroleum Supply Monthly (PSM). The tables in Volumes 1 and 2 are similarly numbered to facilitate comparison between them. Explanatory Notes, located at the end of this publication, present information describing data collection, sources, estimation methodology, data quality control procedures, modifications to reporting requirements and interpretation of tables. Industry terminology and product definitions are listed alphabetically in the Glossary

  2. Natural gas annual 1997

    International Nuclear Information System (INIS)

    1998-10-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1997 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1993 to 1997 for each Census Division and each State. Annual historical data are shown at the national level. 27 figs., 109 tabs

  3. Natural gas annual 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    The Natural Gas Annual provides information on the supply and disposition of natural gas to a wide audience including industry, consumers, Federal and State agencies, and educational institutions. The 1997 data are presented in a sequence that follows natural gas (including supplemental supplies) from its production to its end use. This is followed by tables summarizing natural gas supply and disposition from 1993 to 1997 for each Census Division and each State. Annual historical data are shown at the national level. 27 figs., 109 tabs.

  4. International energy annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    The International Energy Annual presents an overview of key international energy trends for production, consumption, imports, and exports of primary energy commodities in over 220 countries, dependencies, and areas of special sovereignty. Also included are population and gross domestic product data, as well as prices for crude oil and petroleum products in selected countries. Renewable energy reported in the International Energy Annual includes hydroelectric power, geothermal, solar, and wind electric power, biofuels energy for the US, and biofuels electric power for Brazil. New in the 1996 edition are estimates of carbon dioxide emissions from the consumption of petroleum and coal, and the consumption and flaring of natural gas. 72 tabs.

  5. On speech recognition during anaesthesia

    DEFF Research Database (Denmark)

    Alapetite, Alexandre

    2007-01-01

    This PhD thesis in human-computer interfaces (informatics) studies the case of the anaesthesia record used during medical operations and the possibility to supplement it with speech recognition facilities. Problems and limitations have been identified with the traditional paper-based anaesthesia...... and inaccuracies in the anaesthesia record. Supplementing the electronic anaesthesia record interface with speech input facilities is proposed as one possible solution to a part of the problem. The testing of the various hypotheses has involved the development of a prototype of an electronic anaesthesia record...... interface with speech input facilities in Danish. The evaluation of the new interface was carried out in a full-scale anaesthesia simulator. This has been complemented by laboratory experiments on several aspects of speech recognition for this type of use, e.g. the effects of noise on speech recognition...

  6. Discriminative learning for speech recognition

    CERN Document Server

    He, Xiadong

    2008-01-01

    In this book, we introduce the background and mainstream methods of probabilistic modeling and discriminative parameter optimization for speech recognition. The specific models treated in depth include the widely used exponential-family distributions and the hidden Markov model. A detailed study is presented on unifying the common objective functions for discriminative learning in speech recognition, namely maximum mutual information (MMI), minimum classification error, and minimum phone/word error. The unification is presented, with rigorous mathematical analysis, in a common rational-functio

  7. Acoustic modeling for emotion recognition

    CERN Document Server

    Anne, Koteswara Rao; Vankayalapati, Hima Deepthi

    2015-01-01

     This book presents state of art research in speech emotion recognition. Readers are first presented with basic research and applications – gradually more advance information is provided, giving readers comprehensive guidance for classify emotions through speech. Simulated databases are used and results extensively compared, with the features and the algorithms implemented using MATLAB. Various emotion recognition models like Linear Discriminant Analysis (LDA), Regularized Discriminant Analysis (RDA), Support Vector Machines (SVM) and K-Nearest neighbor (KNN) and are explored in detail using prosody and spectral features, and feature fusion techniques.

  8. Simultaneous tracking and activity recognition

    DEFF Research Database (Denmark)

    Manfredotti, Cristina Elena; Fleet, David J.; Hamilton, Howard J.

    2011-01-01

    be used to improve the prediction step of the tracking, while, at the same time, tracking information can be used for online activity recognition. Experimental results in two different settings show that our approach 1) decreases the error rate and improves the identity maintenance of the positional......Many tracking problems involve several distinct objects interacting with each other. We develop a framework that takes into account interactions between objects allowing the recognition of complex activities. In contrast to classic approaches that consider distinct phases of tracking and activity...... tracking and 2) identifies the correct activity with higher accuracy than standard approaches....

  9. Human ear recognition by computer

    CERN Document Server

    Bhanu, Bir; Chen, Hui

    2010-01-01

    Biometrics deals with recognition of individuals based on their physiological or behavioral characteristics. The human ear is a new feature in biometrics that has several merits over the more common face, fingerprint and iris biometrics. Unlike the fingerprint and iris, it can be easily captured from a distance without a fully cooperative subject, although sometimes it may be hidden with hair, scarf and jewellery. Also, unlike a face, the ear is a relatively stable structure that does not change much with the age and facial expressions. ""Human Ear Recognition by Computer"" is the first book o

  10. Familiar Person Recognition: Is Autonoetic Consciousness More Likely to Accompany Face Recognition Than Voice Recognition?

    Science.gov (United States)

    Barsics, Catherine; Brédart, Serge

    2010-11-01

    Autonoetic consciousness is a fundamental property of human memory, enabling us to experience mental time travel, to recollect past events with a feeling of self-involvement, and to project ourselves in the future. Autonoetic consciousness is a characteristic of episodic memory. By contrast, awareness of the past associated with a mere feeling of familiarity or knowing relies on noetic consciousness, depending on semantic memory integrity. Present research was aimed at evaluating whether conscious recollection of episodic memories is more likely to occur following the recognition of a familiar face than following the recognition of a familiar voice. Recall of semantic information (biographical information) was also assessed. Previous studies that investigated the recall of biographical information following person recognition used faces and voices of famous people as stimuli. In this study, the participants were presented with personally familiar people's voices and faces, thus avoiding the presence of identity cues in the spoken extracts and allowing a stricter control of frequency exposure with both types of stimuli (voices and faces). In the present study, the rate of retrieved episodic memories, associated with autonoetic awareness, was significantly higher from familiar faces than familiar voices even though the level of overall recognition was similar for both these stimuli domains. The same pattern was observed regarding semantic information retrieval. These results and their implications for current Interactive Activation and Competition person recognition models are discussed.

  11. Micro-Recognition - Erving Goffman as Recognition Thinker

    DEFF Research Database (Denmark)

    Jacobsen, Michael Hviid; Kristiansen, Søren

    2009-01-01

    and civil inattention guide the conduct of people in many of their face-to-face encounters with each other. This article therefore shows how Goffman may in fact supplement many of the most fashionable and celebrated contemporary recognition theories as advanced by e.g. Nancy Fraser, Charles Taylor or Axel...

  12. Face recognition : implementation of face recognition on AMIGO

    NARCIS (Netherlands)

    Geelen, M.J.A.J.; Molengraft, van de M.J.G.; Elfring, J.

    2011-01-01

    In this (traineeship)report two possible methods of face recognition were presented. The first method describes how to detect and recognize faces by using the SURF algorithm. This algorithm finally was not used for recognizing faces, with the reason that the Eigenface algorithm was an already tested

  13. Interdependence of Inhibitor Recognition in HIV-1 Protease.

    Science.gov (United States)

    Paulsen, Janet L; Leidner, Florian; Ragland, Debra A; Kurt Yilmaz, Nese; Schiffer, Celia A

    2017-05-09

    Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1' and S2' subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. All-atom molecular dynamics simulations starting from these structures were performed and systematically analyzed in terms of atomic fluctuations, intermolecular interactions, and water structure. These analyses reveal that the S1' subsite highly influences other subsites: the extension of the hydrophobic P1' moiety results in 1) reduced van der Waals contacts in the P2' subsite, 2) more variability in the hydrogen bond frequencies with catalytic residues and the flap water, and 3) changes in the occupancy of conserved water sites both proximal and distal to the active site. In addition, one of the monomers in this homodimeric enzyme has atomic fluctuations more highly correlated with DRV than the other monomer. These relationships intricately link the HIV-1 protease subsites and are critical to understanding molecular recognition and inhibitor binding. More broadly, the interdependency of subsite recognition within an active site requires consideration in the selection of chemical moieties in drug design; this strategy is in contrast to what is traditionally done with independent optimization of chemical moieties of an inhibitor.

  14. An automated approach for annual layer counting in ice cores

    Science.gov (United States)

    Winstrup, M.; Svensson, A.; Rasmussen, S. O.; Winther, O.; Steig, E.; Axelrod, A.

    2012-04-01

    The temporal resolution of some ice cores is sufficient to preserve seasonal information in the ice core record. In such cases, annual layer counting represents one of the most accurate methods to produce a chronology for the core. Yet, manual layer counting is a tedious and sometimes ambiguous job. As reliable layer recognition becomes more difficult, a manual approach increasingly relies on human interpretation of the available data. Thus, much may be gained by an automated and therefore objective approach for annual layer identification in ice cores. We have developed a novel method for automated annual layer counting in ice cores, which relies on Bayesian statistics. It uses algorithms from the statistical framework of Hidden Markov Models (HMM), originally developed for use in machine speech recognition. The strength of this layer detection algorithm lies in the way it is able to imitate the manual procedures for annual layer counting, while being based on purely objective criteria for annual layer identification. With this methodology, it is possible to determine the most likely position of multiple layer boundaries in an entire section of ice core data at once. It provides a probabilistic uncertainty estimate of the resulting layer count, hence ensuring a proper treatment of ambiguous layer boundaries in the data. Furthermore multiple data series can be incorporated to be used at once, hence allowing for a full multi-parameter annual layer counting method similar to a manual approach. In this study, the automated layer counting algorithm has been applied to data from the NGRIP ice core, Greenland. The NGRIP ice core has very high temporal resolution with depth, and hence the potential to be dated by annual layer counting far back in time. In previous studies [Andersen et al., 2006; Svensson et al., 2008], manual layer counting has been carried out back to 60 kyr BP. A comparison between the counted annual layers based on the two approaches will be presented

  15. Annual report 2000

    International Nuclear Information System (INIS)

    2001-07-01

    Article VI.J of the Agency's Statute requires the Board of Governors to submit 'an annual report to the General Conference concerning the affairs of the Agency and any projects approved by the Agency'. This report covers the period 1 January to 31 December 2000

  16. IRI annual report 1989

    International Nuclear Information System (INIS)

    1990-01-01

    In this annual report of the Dutch Interfacultary Reactor Institute, summary reports are presented of current research and teaching activities during 1989 of the departments radiochemistry, radiation chemistry, radiation physics and reactor physics, operation and maintenance of, and experiments with the Delft Hoger Onderwijs reactor, nuclear instrumentation projects and supporting services. (H.W.). 299 refs.; 2 figs.; 7 tabs

  17. Annual report 1981

    International Nuclear Information System (INIS)

    1981-12-01

    This annual report contains short descriptions of the work done at the named institute. These concern the study of hyperfine interactions, experiments with synchroton radiation, experiments at storage rings, and experiments at CERN. Furthermore, a list of publications, contributions to conferences and these is presented. (HSI) [de

  18. CSIR Annual report 1966

    CSIR Research Space (South Africa)

    CSIR

    1966-01-01

    Full Text Available This report presents the twenty second annual report of the Council for Scientific and Industrial Research. The report covers the period from the 1st January, 1966, to the 31st December 1966. Balance sheets and statements of income and expenditure...

  19. Annual Report - ESCELSA - 1997

    International Nuclear Information System (INIS)

    1998-01-01

    The annual report of ESCELSA - Brazilian electric power distribution company - introduces the following main topics: state of Espirito Santo; strategic focus; financial performance; relation with investors; energy sales; market overview; market expansion; customers; technological stream; measuring quality; electric system; investments; protecting the environment; and resource allocation

  20. Annual Conference Abstracts

    Science.gov (United States)

    Journal of Engineering Education, 1972

    1972-01-01

    Includes abstracts of papers presented at the 80th Annual Conference of the American Society for Engineering Education. The broad areas include aerospace, affiliate and associate member council, agricultural engineering, biomedical engineering, continuing engineering studies, chemical engineering, civil engineering, computers, cooperative…

  1. Annual report 1996

    International Nuclear Information System (INIS)

    1996-01-01

    This annual report presents an evaluation of activities of the Entomology Unit of the FAO/IAEA Agriculture and Biotechnology Laboratory, Seibersdorf. The major themes of the report include mass rearing and quality control in Tsetse fly and research on Medfly genetic sexing strains

  2. Annual report 1999

    International Nuclear Information System (INIS)

    1999-01-01

    This annual report presents an evaluation of activities of the Entomology Unit of the FAO/IAEA Agriculture and Biotechnology Laboratory, Seibersdorf. The major themes of the report include mass rearing and quality control in Tsetse fly and research on Medfly genetic sexing strains

  3. Annual report 1997

    International Nuclear Information System (INIS)

    1997-01-01

    This annual report presents an evaluation of activities of the Entomology Unit of the FAO/IAEA Agriculture and Biotechnology Laboratory, Seibersdorf. The major themes of the report include mass rearing and quality control in Tsetse fly and research on Medfly genetic sexing strains

  4. CSIR Annual report 1968

    CSIR Research Space (South Africa)

    CSIR

    1968-01-01

    Full Text Available This report presents the twenty fourth annual report of the Council for Scientific and Industrial Research. The report covers the period from the 1st January, 1968, to the 31st December 1968. Balance sheets and statements of income and expenditure...

  5. CSIR Annual report 1971

    CSIR Research Space (South Africa)

    CSIR

    1971-01-01

    Full Text Available This report presents the twenty seventh annual report of the Council for Scientific and Industrial Research. The report covers the period from the 1st January, 1971, to the 31st December 1971. Balance sheets and statements of income and expenditure...

  6. CSIR Annual report 1970

    CSIR Research Space (South Africa)

    CSIR

    1970-01-01

    Full Text Available This report presents the twenty sixth annual report of the Council for Scientific and Industrial Research. The report covers the period from the 1st January, 1970, to the 31st December 1970. Balance sheets and statements of income and expenditure...

  7. CSIR Annual report 1969

    CSIR Research Space (South Africa)

    CSIR

    1969-01-01

    Full Text Available This report presents the twenty fifth annual report of the Council for Scientific and Industrial Research. The report covers the period from the 1st January, 1969, to the 31st December 1969. Balance sheets and statements of income and expenditure...

  8. International energy annual, 1991

    International Nuclear Information System (INIS)

    1992-12-01

    This report is prepared annually and presents the latest information and trends on world energy production and consumption for petroleum, natural gas, coal, and electricity. Trade and reserves are shown for petroleum, natural gas, and coal. Prices are included for selected petroleum products. Production and consumption data are reported in standard units as well as British thermal units (Btu) and joules

  9. Uranium industry annual 1998

    International Nuclear Information System (INIS)

    1999-01-01

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ''Uranium Industry Annual Survey.'' Data provides a comprehensive statistical characterization of the industry's activities for the survey year and also include some information about industry's plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ''Uranium Industry Annual Survey'' is provided in Appendix C. The Form EIA-858 ''Uranium Industry Annual Survey'' is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs

  10. KTA annual report 1980

    International Nuclear Information System (INIS)

    The annual report gives an overview of the rulemaking work in the individual fields as well as other activities, such as meetings, international codes of rules, and publications. KTA organization, including its administration and funds is listed. (orig./HP) [de

  11. IRI annual report 1989

    International Nuclear Information System (INIS)

    1990-01-01

    In this annual report of the Dutch Interfacultary Reactor Institute, summary reports are presented of current research and teaching activities during 1989 of the departments radiochemistry, radiation chemistry, radiation physics and reactor physics, operation and maintenance of, and experiments with the Delft Hoger Onderwijs reactor, nuclear instrumentation projects and supporting services. (H.W.). 145 refs.; 20 figs.; 4 fotos; 2 tabs

  12. Annual report 1981

    International Nuclear Information System (INIS)

    1982-01-01

    In this annual report the work done at the named Institute is described. This concerns particle and fields in the solar system, infrared astronomy, X-ray astronomy, γ-astronomy, and molecule spectroscopy. A list of publications is added. (HSI)

  13. ANCLI annual report 2003

    International Nuclear Information System (INIS)

    2003-01-01

    The National Association for the Information Local Commissions (ANCLI) was created in september 1999. This association aims to develop an exchange and information network for the information local commissions. In this framework it develops information sheets, Internet site, nuclear centers visits, colloquium and formations organizations. This report presents the annual activities for the year 2003. (A.L.B.)

  14. ANCLI annual report 2004

    International Nuclear Information System (INIS)

    2004-01-01

    The National Association for the Information Local Commissions (ANCLI) was created in september 1999. This association aims to develop an exchange and information network for the information local commissions. In this framework it develops information sheets, Internet site, nuclear centers visits, colloquium and formations organizations. This report presents the annual activities for the year 2004. (A.L.B.)

  15. Annual Report 2008

    Energy Technology Data Exchange (ETDEWEB)

    Keeley, N; Skalski, J [The Andrzej Soltan Institute for Nuclear Studies, Swierk-Otwock (Poland)

    2009-07-01

    The ''Annual Report 2008'' describes activities of Andrzej Soltan Institute for Nuclear Studies in 2008. Report consists of two parts. First one consists of general information about location, management, scientific council, personnel, financial support and conferences while the second one describes the scientific activity of Institute. A Foreword to all report written by Director of the Institute prof. Grzegorz Wrochna is also given.

  16. TIARA annual report 2004

    International Nuclear Information System (INIS)

    Ohara, Yoshihiro; Arakawa, Kazuo; Tanaka, Shigeru; Narumi, Kazumasa; Yoshida, Masaru; Itoh, Hisayoshi; Yoshikawa, Masato; Tanaka, Atsushi; Kobayashi, Yasuhiko; Fukuda, Mitsuhiro; Otsubo, Michiro; Yokota, Watalu; Nakamura, Yoshiteru

    2006-01-01

    This annual report describes research and development activities which have been performed with the TIARA (Takasaki Ion Accelerators for Advanced Radiation Application) facilities from April 1, 2004 to March 31, 2005. The 126 of the presented papers are indexed individually. A list of publications, the type of research collaborations and organization of TIARA are also given as appendices. (J.P.N.)

  17. Annual Report 2000

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The Institut Laue-Langevin (ILL) is an international research center using neutrons to probe the microscopic structure and dynamics of a broad range of materials. This annual report presents the ILL activities in 2000: the scientific highlights, the Millennium programme and the new developments, the workshops organized by the ILL, the experimental programme and the publications. (A.L.B.)

  18. International Energy Annual, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-14

    This report is prepared annually and presents the latest information and trends on world energy production and consumption for petroleum, natural gas, coal, and electricity. Trade and reserves are shown for petroleum, natural gas, and coal. Prices are included for selected petroleum products. Production and consumption data are reported in standard units as well as British thermal units (Btu) and joules.

  19. ANCLI annual report 2002

    International Nuclear Information System (INIS)

    2002-01-01

    The National Association for the Information Local Commissions (ANCLI) was created in september 1999. This association aims to develop an exchange and information network for the information local commissions. In this framework it develops information sheets, Internet site, nuclear centers visits, colloquium and formations organizations. This report presents the annual activities for the year 2002. (A.L.B.)

  20. Annual General Meetings

    OpenAIRE

    2009-01-01

    We have produced this information booklet to explain why companies must – by law – hold an Annual General Meeting (AGM). The laws which cover AGMs are known as the Companies Acts. This guide gives only a summary of the rules for AGMs. If you have a concern about the AGM of a particular company, you should get independent legal advice.