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Sample records for cholesterol-vinyl ether-peg conjugate

  1. Revisiting conjugate schedules.

    Science.gov (United States)

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed.

  2. Revisiting conjugate schedules.

    Science.gov (United States)

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed. PMID:26150349

  3. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    G Padmanaban; S Ramakrishnan

    2003-08-01

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying excitation energies. The latter feature, especially when the chromophores are fluorescent, like in MEHPPV, makes these systems particularly interesting from the photophysics point of view. Segmented MEHPPV- samples, where x represents the mole fraction of conjugated segments, were prepared by a novel approach that utilizes a suitable precursor wherein selective elimination of one of the two eliminatable groups is affected; the uneliminated units serve as conjugation truncations. Control of the composition x of the precursor therefore permits one to prepare segmented MEHPPV- samples with varying levels of conjugation (elimination). Using fluorescence spectroscopy, we have seen that even in single isolated polymer chains, energy migration from the shorter (higher energy) chromophores to longer (lower energy) ones occurs – the extent of which depends on the level of conjugation. Further, by varying the solvent composition, it is seen that the extent of energy transfer and the formation of poorly emissive inter-chromophore excitons are greatly enhanced with increasing amounts of non-solvent. A typical S-shaped curve represents the variation of emission yields as a function of composition suggestive of a cooperative collapse of the polymer coil, reminiscent of conformational transitions seen in biological macromolecules.

  4. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  5. Qualidade conjugal: mapeando conceitos

    OpenAIRE

    Clarisse Mosmann; Adriana Wagner; Terezinha Féres-Carneiro

    2006-01-01

    Apesar da ampla utilização do conceito de qualidade conjugal, identifica-se falta de clareza conceitual acerca das variáveis que o compõem. Esse artigo apresenta revisão da literatura na área com o objetivo de mapear o conceito de qualidade conjugal. Foram analisadas sete principais teorias sobre o tema: Troca Social, Comportamental, Apego, Teoria da Crise, Interacionismo Simbólico. Pelos postulados propostos nas diferentes teorias, podem-se identificar três grupos de variáveis fundamentais n...

  6. Stabilized polyacrylic saccharide protein conjugates

    Science.gov (United States)

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1996-02-20

    This invention is directed to water soluble protein polymer conjugates which are stable in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups. 16 figs.

  7. DNA-cell conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  8. Conjugation in "Escherichia coli"

    Science.gov (United States)

    Phornphisutthimas, Somkiat; Thamchaipenet, Arinthip; Panijpan, Bhinyo

    2007-01-01

    Bacterial conjugation is a genetic transfer that involves cell-to-cell between donor and recipient cells. With the current method used to teach students in genetic courses at the undergraduate level, the transconjugants are identified using bacterial physiology and/or antibiotic resistance. Using physiology, however, is difficult for both…

  9. Peptide-Carrier Conjugation

    DEFF Research Database (Denmark)

    Hansen, Paul Robert

    2015-01-01

    To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....

  10. Conjugated polymer nanoparticles

    Science.gov (United States)

    Tuncel, Dönüs; Demir, Hilmi Volkan

    2010-04-01

    Conjugated polymer nanoparticles are highly versatile nano-structured materials that can potentially find applications in various areas such as optoelectronics, photonics, bio-imaging, bio-sensing and nanomedicine. Their straightforward synthesis in desired sizes and properties, biocompatibility and non-toxicity make these materials highly attractive for the aforementioned applications. This feature article reviews the recent developments in the synthesis, characterization, properties and application of these exciting nanostructured materials.

  11. Anti- (conjugate) linearity

    Science.gov (United States)

    Uhlmann, Armin

    2016-03-01

    This is an introduction to antilinear operators. In following Wigner the terminus antilinear is used as it is standard in Physics. Mathematicians prefer to say conjugate linear. By restricting to finite-dimensional complex-linear spaces, the exposition becomes elementary in the functional analytic sense. Nevertheless it shows the amazing differences to the linear case. Basics of antilinearity is explained in sects. 2, 3, 4, 7 and in sect. 1.2: Spectrum, canonical Hermitian form, antilinear rank one and two operators, the Hermitian adjoint, classification of antilinear normal operators, (skew) conjugations, involutions, and acq-lines, the antilinear counterparts of 1-parameter operator groups. Applications include the representation of the Lagrangian Grassmannian by conjugations, its covering by acq-lines. As well as results on equivalence relations. After remembering elementary Tomita-Takesaki theory, antilinear maps, associated to a vector of a two-partite quantum system, are defined. By allowing to write modular objects as twisted products of pairs of them, they open some new ways to express EPR and teleportation tasks. The appendix presents a look onto the rich structure of antilinear operator spaces.

  12. Theory of Digitized Conjugate Surface and Solution to Conjugate Surface

    Institute of Scientific and Technical Information of China (English)

    Xiao Lai-yuan; Liao Dao-xun; Yi Chuan-yun

    2004-01-01

    In order to meet the needs of designing and processing digitized surfaces, the method to spreading digitized surface has been proposed. The key technique is to solve the problem of digitized conjugate surface. In the paper, the digitized conjugate surface was theoretically investigated, and the solution of conjugate surface based on digitized surface was also studied. The digitized conjugate surface theory was then proposed, and applied to build the model of solving conjugate surface based on digitized surface. A corresponding algorithm was developed. This paper applies the software Conjugater-1.0 that is developed by ourselves to compute the digitized conjugate surfaces of the drum-tooth surface. This study provides theoretical and technical bases for analyzing engagement of digitized surface, simulation and numerical processing technique.

  13. Organometallic B12-DNA conjugate

    DEFF Research Database (Denmark)

    Hunger, Miriam; Mutti, Elena; Rieder, Alexander;

    2014-01-01

    Design, synthesis, and structural characterization of a B12-octadecanucleotide are presented herein, a new organometallic B12-DNA conjugate. In such covalent conjugates, the natural B12 moiety may be a versatile vector for controlled in vivo delivery of oligonucleotides to cellular targets in hum...

  14. Dihydroazulene-buckminsterfullerene conjugates

    DEFF Research Database (Denmark)

    Santella, Marco; Mazzanti, Virginia; Jevric, Martyn;

    2012-01-01

    The dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch has recently attracted interest as a molecular switch for molecular electronics. In this field, Buckminsterfullerene, C(60), has been shown to be a useful anchoring group for adhering a molecular wire to an electrode. Here we have...... combined the two units with the overall aim to elucidate how C(60) influences the DHA-VHF switching events. Efficient synthetic protocols for making covalently linked DHA-C(60) conjugates were developed, using Prato, Sonogashira, Hay, and Cadiot-Chodkiewicz reactions. These syntheses provide as well...... a variety of potentially useful DHA and C(60) building blocks for acetylenic scaffolding. The two units were separated by bridges of various lengths, such as oligo(phenyleneethynylene) (OPE2 and OPE3) wires. The distance of separation was found to influence strongly the light-induced ring-opening reaction...

  15. Generalized conjugate gradient squared

    Energy Technology Data Exchange (ETDEWEB)

    Fokkema, D.R.; Sleijpen, G.L.G. [Utrecht Univ. (Netherlands)

    1994-12-31

    In order to solve non-symmetric linear systems of equations, the Conjugate Gradient Squared (CGS) is a well-known and widely used iterative method. In practice the method converges fast, often twice as fast as the Bi-Conjugate Gradient method. This is what you may expect, since CGS uses the square of the BiCG polynomial. However, CGS may suffer from its erratic convergence behavior. The method may diverge or the approximate solution may be inaccurate. BiCGSTAB uses the BiCG polynomial and a product of linear factors in an attempt to smoothen the convergence. In many cases, this has proven to be very effective. Unfortunately, the convergence of BiCGSTAB may stall when a linear factor (nearly) degenerates. BiCGstab({ell}) is designed to overcome this degeneration of linear factors. It generalizes BiCGSTAB and uses both the BiCG polynomial and a product of higher order factors. Still, CGS may converge faster than BiCGSTAB or BiCGstab({ell}). So instead of using a product of linear or higher order factors, it may be worthwhile to look for other polynomials. Since the BiCG polynomial is based on a three term recursion, a natural choice would be a polynomial based on another three term recursion. Possibly, a suitable choice of recursion coefficients would result in method that converges faster or as fast as CGS, but less erratic. It turns out that an algorithm for such a method can easily be formulated. One particular choice for the recursion coefficients leads to CGS. Therefore one could call this algorithm generalized CGS. Another choice for the recursion coefficients leads to BiCGSTAB. It is therefore possible to mix linear factors and some polynomial based on a three term recursion. This way one may get the best of both worlds. The authors will report on their findings.

  16. Star-Shaped Conjugated Systems

    Directory of Open Access Journals (Sweden)

    Heiner Detert

    2010-05-01

    Full Text Available The present review deals with the preparation and the properties of star-shaped conjugated compounds. Three, four or six conjugated arms are attached to cross-conjugated cores, which consist of single atoms (B, C+, N, benzene or azine rings or polycyclic ring systems, as for example triphenylene or tristriazolotriazine. Many of these shape-persistent [n]star compounds tend to π-stacking and self-organization, and exhibit interesting properties in materials science: Linear and non-linear optics, electrical conductivity, electroluminescence, formation of liquid crystalline phases, etc.

  17. Sequential measurements of conjugate observables

    Energy Technology Data Exchange (ETDEWEB)

    Carmeli, Claudio [Dipartimento di Fisica, Universita di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Heinosaari, Teiko [Department of Physics and Astronomy, Turku Centre for Quantum Physics, University of Turku, 20014 Turku (Finland); Toigo, Alessandro, E-mail: claudio.carmeli@gmail.com, E-mail: teiko.heinosaari@utu.fi, E-mail: alessandro.toigo@polimi.it [Dipartimento di Matematica ' Francesco Brioschi' , Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2011-07-15

    We present a unified treatment of sequential measurements of two conjugate observables. Our approach is to derive a mathematical structure theorem for all the relevant covariant instruments. As a consequence of this result, we show that every Weyl-Heisenberg covariant observable can be implemented as a sequential measurement of two conjugate observables. This method is applicable both in finite- and infinite-dimensional Hilbert spaces, therefore covering sequential spin component measurements as well as position-momentum sequential measurements.

  18. Research study of conjugate materials; Conjugate material no chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The paper reported an introductory research on possibilities of new glass `conjugate materials.` The report took up the structure and synthetic process of conjugate materials to be researched/developed, classified them according to structural elements on molecular, nanometer and cluster levels, and introduced the structures and functions. Further, as glasses with new functions to be proposed, the paper introduced transparent and high-strength glass used for houses and vehicles, light modulation glass which realizes energy saving and optical data processing, and environmentally functional glass which realizes environmental cleaning or high performance biosensor. An initial survey was also conducted on rights of intellectual property to be taken notice of in Japan and abroad in the present situation. Reports were summed up and introduced of Osaka National Research Institute, Electrotechnical Laboratory, and National Industrial Research Institute of Nagoya which are all carrying out leading studies of conjugate materials. 235 refs., 135 figs., 6 tabs.

  19. A Geometric View of Conjugate Priors

    CERN Document Server

    Agarwal, Arvind

    2010-01-01

    In Bayesian machine learning, conjugate priors are popular, mostly due to mathematical convenience. In this paper, we show that there are deeper reasons for choosing a conjugate prior. Specifically, we formulate the conjugate prior in the form of Bregman divergence and show that it is the inherent geometry of conjugate priors that makes them appropriate and intuitive. This geometric interpretation allows one to view the hyperparameters of conjugate priors as the {\\it effective} sample points, thus providing additional intuition. We use this geometric understanding of conjugate priors to derive the hyperparameters and expression of the prior used to couple the generative and discriminative components of a hybrid model for semi-supervised learning.

  20. Persistence Mechanisms of Conjugative Plasmids

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Hansen, Lars H.; Sørensen, Søren Johannes

    2009-01-01

    maintenance in the host cell. These importantly include the ability to self-mobilize in a process termed conjugative transfer, which may occur across species barriers. Other plasmid stabilizing mechanisms include the multimer resolution system, active partitioning, and post-segregational-killing of plasmid......Are plasmids selfish parasitic DNA molecules or an integrated part of the bacterial genome? This chapter reviews the current understanding of the persistence mechanisms of conjugative plasmids harbored by bacterial cells and populations. The diversity and intricacy of mechanisms affecting the...... successful propagation and long-term continued existence of these extra-chromosomal elements is extensive. Apart from the accessory genetic elements that may provide plasmid-harboring cells a selective advantage, special focus is placed on the mechanisms conjugative plasmids employ to ensure their stable...

  1. On contravariant product conjugate connections

    Directory of Open Access Journals (Sweden)

    A. M. Blaga

    2012-02-01

    Full Text Available Invariance properties for the covariant and contravariant connections on a Riemannian manifold with respect to an almost product structure are stated. Restricting to a distribution of the contravariant connections is also discussed. The particular case of the conjugate connection is investigated and properties of the extended structural and virtual tensors for the contravariant connections are given.

  2. Glutathione conjugation as a bioactivation reaction

    NARCIS (Netherlands)

    Bladeren, P.J. van

    2000-01-01

    In general, glutathione conjugation is regarded as a detoxication reaction. However, depending on the properties of the substrate, bioactivation is also possible. Four types of activation reaction have been recognized: direct-acting compounds, conjugates that are activated through cysteine conjugate

  3. Conjugative plasmids of Neisseria gonorrhoeae.

    Directory of Open Access Journals (Sweden)

    Emilia Pachulec

    Full Text Available Many clinical isolates of the human pathogen Neisseria gonorrhoeae contain conjugative plasmids. The host range of these plasmids is limited to Neisseria species, but presence of a tetracycline (tetM determinant inserted in several of these plasmids is an important cause of the rapid spread of tetracycline resistance. Previously plasmids with different backbones (Dutch and American type backbones and with and without different tetM determinants (Dutch and American type tetM determinants have been identified. Within the isolates tested, all plasmids with American or Dutch type tetM determinants contained a Dutch type plasmid backbone. This demonstrated that tetM determinants should not be used to differentiate between conjugal plasmid backbones. The nucleotide sequences of conjugative plasmids with Dutch type plasmid backbones either not containing the tetM determinant (pEP5233 or containing Dutch (pEP5289 or American (pEP5050 type tetM determinants were determined. Analysis of the backbone sequences showed that they belong to a novel IncP1 subfamily divergent from the IncP1alpha, beta, gamma, delta and epsilon subfamilies. The tetM determinants were inserted in a genetic load region found in all these plasmids. Insertion was accompanied by the insertion of a gene with an unknown function, and rearrangement of a toxin/antitoxin gene cluster. The genetic load region contains two toxin/antitoxins of the Zeta/Epsilon toxin/antitoxin family previously only found in Gram positive organisms and the virulence associated protein D of the VapD/VapX toxin/antitoxin family. Remarkably, presence of VapX of pJD1, a small cryptic neisserial plasmid, in the acceptor strain strongly increased the conjugation efficiency, suggesting that it functions as an antitoxin for the conjugative plasmid. The presence of the toxin and antitoxin on different plasmids might explain why the host range of this IncP1 plasmid is limited to Neisseria species. The isolated plasmids

  4. The ISG15 conjugation system.

    Science.gov (United States)

    Durfee, Larissa A; Huibregtse, Jon M

    2012-01-01

    ISG15 is a ubiquitin-like modifier that is expressed in response to type 1 interferon signaling (IFN-α/β) and plays a role in antiviral responses. The core E1, E2, and E3 enzymes for ISG15 are Ube1L, UbcH8, and Herc5, respectively, and these are all also induced at the transcriptional level by IFN-α/β. We recently showed that Herc5 associates with polysomes and modifies target proteins in a cotranslational manner. Here, we describe the expression of the core conjugating enzymes in human cells, the detection of ISG15 conjugates, and the methods for fractionation of Herc5 with polysomes. PMID:22350882

  5. Conjugated Polymers for Energy Production

    DEFF Research Database (Denmark)

    Livi, Francesco

    This dissertation is aimed at developing materials for flexible, large area, ITO-free polymer solar cells (PSCs) fully printed under ambient conditions. A large screening of conjugated polymers, both novel and well-known materials, has been carried out in order to find suitable candidates...... for scalable PSCs fully printed under ambient conditions [Adv. Energy Mater. 2015, 5, 1402186]. PPDTBT resulted to be the conjugated polymer with the best photovoltaic performance within the 104 synthesized macromolecules. Therefore, further studies have been done on such material. The impact of side chain...... arylation (DAr) and direct arylation polymerization (DArP) have been applied to the preparation of PPDTBT, making this polymer readily available in only 4 synthetic steps and thus easily transferable to a large scale-production setup. DArP avoids organometallic species and therefore is an appealing...

  6. Conjugated polyelectrolytes fundamentals and applications

    CERN Document Server

    Liu, Bin

    2013-01-01

    This is the first monograph to specifically focus on fundamentals and applications of polyelectrolytes, a class of molecules that gained substantial interest due to their unique combination of properties. Combining both features of organic semiconductors and polyelectrolytes, they offer a broad field for fundamental research as well as applications to analytical chemistry, optical imaging, and opto-electronic devices. The initial chapters introduce readers to the synthesis, optical and electrical properties of various conjugated polyelectrolytes. This is followed by chapters on the applica

  7. ON CONJUGATES AND MODULII OF BICOMPLEX NUMBERS

    Directory of Open Access Journals (Sweden)

    JAISHREE

    2012-06-01

    Full Text Available The paper presents extensive use of complex pairs to develop the algebraic properties of bicomplex numbers and contains various aspects of finding the conjugates and modulii of bicomplex numbers.We discuss three types of conjugations and some specific modulii with complex and hyperbolic ranges. We also examine the impact of different conjugations on the principal ideals I1 and I2.

  8. Cysteine S-conjugate β-lyases

    OpenAIRE

    Arthur J. L. Cooper; Krasnikov, Boris F.; Pinto, John T.; Bruschi, Sam A.

    2010-01-01

    Cysteine S-conjugate β-lyases are pyridoxal 5′-phosphate (PLP)-containing enzymes that catalyze the conversion of cysteine S-conjugates [RSCH2CH(NH3+)CO2−] and selenium Se-conjugates [RSeCH2CH(NH3+)CO2−] that contain a leaving group in the β position to pyruvate, ammonium and a sulfur-containing fragment (RSH) or selenium-containing fragment (RSeH), respectively. At least ten PLP enzymes catalyze β-elimination reactions with such cysteine S-conjugates. All are enzymes involved in amino acid m...

  9. Solution assembly of conjugated polymers

    Science.gov (United States)

    Bokel, Felicia A.

    This dissertation focuses on the solution-state polymer assembly of conjugated polymers with specific attention to nano- and molecular-scale morphology. Understanding how to control these structures holds potential for applications in polymer-based electronics. Optimization of conjugated polymer morphology was performed with three objectives: 1) segregation of donor and acceptor materials on the nanometer length-scale, 2) achieving molecular-scale ordering in terms of crystallinity within distinct domains, and 3) maximizing the number and quality of well-defined donor/acceptor interfaces. Chapter 1 introduces the development of a mixed solvent method to create crystalline poly(3-hexyl thiophene) (P3HT) fibrils in solution. Chapter 2 describes fibril purification and approaches to robust and functional fibrils, while chapters 3 and 4 demonstrate the formation of hybrid nanocomposite wires of P3HT and cadmium selenide (CdSe) nanoparticles by two methods: 1) co-crystallization of free and P3HT-grafted CdSe for composite nanowires and 2) direct attachment of CdSe nanoparticles at fibril edges to give superhighway structures. These composite structures show great potential in the application of optoelectronic devices, such as the active layer of solar cells. Finally, ultrafast photophysical characterization of these polymers, using time-resolved photoluminescence and transient absorption, was performed to determine the aggregation types present in suspended fibrils and monitor the formation and decay of charged species in fibrils and donor-acceptor systems.

  10. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  11. CONJUGATE-SYMPLECTICITY OF LINEAR MULTISTEP METHODS

    Institute of Scientific and Technical Information of China (English)

    Ernst Hairer

    2008-01-01

    For the numerical treatment of Hamiltonian differential equations, symplectic integra-tors are the most suitable choice, and methods that are conjugate to a symplectic integrator share the same good long-time behavior. This note characterizes linear multistep methods whose underlying one-step method is conjugate to a symplectic integrator. The bounded-hess of parasitic solution components is not addressed.

  12. The Conjugate Acid-Base Chart.

    Science.gov (United States)

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  13. DENDRIMER CONJUGATES FOR SELECTIVE OF PROTEIN AGGREGATES

    DEFF Research Database (Denmark)

    2004-01-01

    Dendrimer conjugates are presented, which are formed between a dendrimer and a protein solubilising substance. Such dendrimer conjugates are effective in the treatment of protein aggregate-related diseases (e.g. prion-related diseases). The protein solubilising substance and the dendrimer together...

  14. Kinetic models of conjugated metabolic cycles

    Science.gov (United States)

    Ershov, Yu. A.

    2016-01-01

    A general method is developed for the quantitative kinetic analysis of conjugated metabolic cycles in the human organism. This method is used as a basis for constructing a kinetic graph and model of the conjugated citric acid and ureapoiesis cycles. The results from a kinetic analysis of the model for these cycles are given.

  15. LEDs based on conjugated PPV block copolymers

    NARCIS (Netherlands)

    Brouwer, H.J.; Hilberer, A.; Krasnikov, V.V.; Werts, M.; Wildeman, J.; Hadziioannou, G.

    1997-01-01

    A way to control the bandgap in semi-conducting polymers is by preparing polymers with a partially conjugated backbone. In our laboratory, three conjugated copolymers containing PPV trimers as light emitting chromophores have been synthesized, which emit in the blue, green and orange wavelength regi

  16. CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

    NARCIS (Netherlands)

    Hilberer, A; Gill, R.E; Herrema, J.K; Malliaras, G.G; Wildeman, J.; Hadziioannou, G

    1995-01-01

    In this article we review results obtained in our laboratory on the design and study of new light-emitting polymers. We are interested in the synthesis and characterisation of block copolymers with regularly alternating conjugated and non conjugated sequences. The blocks giving rise to luminescence

  17. Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

    Institute of Scientific and Technical Information of China (English)

    Xueke Ding; Jian Rong; Hong Bai; Xiu Wang; Jine Shen; Fang Li

    2008-01-01

    A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO,which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.

  18. Immunization of newborns with bacterial conjugate vaccines.

    Science.gov (United States)

    van den Biggelaar, Anita H J; Pomat, William S

    2013-05-17

    Bacterial conjugate vaccines are based on the principle of coupling immunogenic bacterial capsular polysaccharides to a carrier protein to facilitate the induction of memory T-cell responses. Following the success of Haemophilus influenzae type b conjugate vaccines in the 1980s, conjugate vaccines for Streptococcus pneumoniae and Neisseria meningitidis infections were developed and proven to be effective in protecting children against invasive disease. In this review, the use of conjugate vaccines in human newborns is discussed. Neonatal Haemophilus influenzae type b and pneumococcal conjugate vaccination schedules have been trialed and proven to be safe, with the majority of studies demonstrating no evidence for the induction of immune tolerance. Whether their neonatal administration also results in an earlier induction of clinical protection in the first 2-3 critical months of life is still to be demonstrated. PMID:22728221

  19. Photoconductive properties of conjugated polymers

    CERN Document Server

    Halls, J J M

    1997-01-01

    The research described in my dissertation has involved the fabrication and characterisation of photovoltaic cells based on conjugated polymers, including the widely studied polymer poly(p-phenylenevinylene). These materials have semiconducting properties which arise from the delocalisation of electrons along the pi-electron systems of the polymer chains. Research into these materials is motivated both by their novel electronic properties, and also their potential for use in a wide range of applications including light-emitting diodes (LEDs), thin-film transistors, and photovoltaic cells (solar cells and light detectors). Light absorbed in a photovoltaic cell generates opposite charges which are collected at two different electrodes, giving rise to an electric current

  20. TAT Peptide and Its Conjugates: Proteolytic Stability

    Science.gov (United States)

    Grunwald, Jacob; Rejtar, Tomas; Sawant, Rupa; Wang, Zhouxi; Torchilin, Vladimir P.

    2009-01-01

    The proteolytic cleavage of TATp, TATp-PEG1000-PE conjugate (TATp-conjugate), and TATp as TATp-conjugate in mixed micelles made of TATp-conjugate and PEG5000-PE (2.5% mol of TATp-conjugate, TATp-Mic) were studied by HPLC with fluorescent detection using fluorenylmethyl chloroformate (FMOC) labeling and by MALDI-TOF MS analysis. The cleavage kinetics were analyzed in human blood plasma and in trypsin-containing phosphate buffered saline (PBS), pH 7.4, to simulate the proteolytic activity of human plasma. The trypsinolysis of free TATp, TATp-conjugate, and TATp-Mic revealed that the main initial fragmentation is an endocleavage at the carboxyl terminus resulting in an Arg-Arg (RR) dimer. The trypsinolysis followed pseudo-first-order kinetics. The cleavage of the free TATp was relatively fast with a half-life of a few minutes (t1/2 ∼ 3.5 min). The TATp-conjugate showed more stability with about a 3-fold increase in half-life (t1/2 ∼ 10 min). TATp in TATp-Mic was highly protected against proteolysis with an over 100-fold increase in half-life (t1/2 ∼ 430 min). The shielding of TATp by PEG moieties in the proposed TATp-Mic is of great importance for its potential use as a cell-penetrating moiety for multifunctional “smart” drug delivery systems with detachable PEG. PMID:19601640

  1. Mitigation of nonlinearities using conjugate data repetition.

    Science.gov (United States)

    Eliasson, Henrik; Johannisson, Pontus; Karlsson, Magnus; Andrekson, Peter A

    2015-02-01

    We investigate a time-domain implementation of generalized phase-conjugated twin waves which we call conjugate data repetition. A theory based on time-domain perturbation analysis explaining the mitigation of nonlinear effects is provided, and the concept is evaluated using numerical simulations. Compared to PM-QPSK at the same channel bit rate, the single-channel transmission reach in a conventional system with standard single-mode fiber of conjugate data repetition-QPSK is increased by approximately a factor of 2. PMID:25836107

  2. Modelling conjugation with stochastic differential equations

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Hasman, Henrik;

    2010-01-01

    Enterococcus faecium strains in a rich exhaustible media. The model contains a new expression for a substrate dependent conjugation rate. A maximum likelihood based method is used to estimate the model parameters. Different models including different noise structure for the system and observations are compared...... using a likelihood-ratio test and Akaike's information criterion. Experiments indicating conjugation on the agar plates selecting for transconjugants motivates the introduction of an extended model, for which conjugation on the agar plate is described in the measurement equation. This model is compared...

  3. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...... fluorescent peptides were designed and synthesized as part of two collaboration projects utilizing peptide conjugates in nanoscale applications to increase understanding of the role peptides and proteins plays in biological systems. Ras proteins are membrane bound molecular switches involved in many signaling...

  4. Conjugated amplifying polymers for optical sensing applications.

    Science.gov (United States)

    Rochat, Sébastien; Swager, Timothy M

    2013-06-12

    Thanks to their unique optical and electrochemical properties, conjugated polymers have attracted considerable attention over the last two decades and resulted in numerous technological innovations. In particular, their implementation in sensing schemes and devices was widely investigated and produced a multitude of sensory systems and transduction mechanisms. Conjugated polymers possess numerous attractive features that make them particularly suitable for a broad variety of sensing tasks. They display sensory signal amplification (compared to their small-molecule counterparts) and their structures can easily be tailored to adjust solubility, absorption/emission wavelengths, energy offsets for excited state electron transfer, and/or for use in solution or in the solid state. This versatility has made conjugated polymers a fluorescence sensory platform of choice in the recent years. In this review, we highlight a variety of conjugated polymer-based sensory mechanisms together with selected examples from the recent literature.

  5. Design and Application of Antimicrobial Peptide Conjugates

    Directory of Open Access Journals (Sweden)

    Andre Reinhardt

    2016-05-01

    Full Text Available Antimicrobial peptides (AMPs are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry.

  6. Conjugated microporous polymers: design, synthesis and application.

    Science.gov (United States)

    Xu, Yanhong; Jin, Shangbin; Xu, Hong; Nagai, Atsushi; Jiang, Donglin

    2013-10-21

    Conjugated microporous polymers (CMPs) are a class of organic porous polymers that combine π-conjugated skeletons with permanent nanopores, in sharp contrast to other porous materials that are not π-conjugated and with conventional conjugated polymers that are nonporous. As an emerging material platform, CMPs offer a high flexibility for the molecular design of conjugated skeletons and nanopores. Various chemical reactions, building blocks and synthetic methods have been developed and a broad variety of CMPs with different structures and specific properties have been synthesized, driving the rapid growth of the field. CMPs are unique in that they allow the complementary utilization of π-conjugated skeletons and nanopores for functional exploration; they have shown great potential for challenging energy and environmental issues, as exemplified by their excellent performance in gas adsorption, heterogeneous catalysis, light emitting, light harvesting and electrical energy storage. This review describes the molecular design principles of CMPs, advancements in synthetic and structural studies and the frontiers of functional exploration and potential applications.

  7. Geometric and Meshing Properties of Conjugate Curves for Gear Transmission

    Directory of Open Access Journals (Sweden)

    Dong Liang

    2014-01-01

    Full Text Available Conjugate curves have been put forward previously by authors for gear transmission. Compared with traditional conjugate surfaces, the conjugate curves have more flexibility and diversity in aspects of gear design and generation. To further extend its application in power transmission, the geometric and meshing properties of conjugate curves are discussed in this paper. Firstly, general principle descriptions of conjugate curves for arbitrary axial position are introduced. Secondly, geometric analysis of conjugate curves is carried out based on differential geometry including tangent and normal in arbitrary contact direction, characteristic point, and curvature relationships. Then, meshing properties of conjugate curves are further revealed. According to a given plane or spatial curve, the uniqueness of conjugated curve under different contact angle conditions is discussed. Meshing commonality of conjugate curves is also demonstrated in terms of a class of spiral curves contacting in the given direction for various gear axes. Finally, a conclusive summary of this study is given.

  8. Complex conjugate pairs in stationary Sturmians

    International Nuclear Information System (INIS)

    Sturmian expansions enable a simply accurate separable specification of two nucleon t matrices based upon realistic two nucleon interactions. Sturmian eigenstates specified by stationary scattering boundary conditions are particularly useful in that context, and they can be calculated by solving a generalised eigenvalue equation using real and symmetric matrices. In general, the spectrum of such an equation may contain complex eigenvalues. But to each complex eigenvalues there is a corresponding conjugate partner. In studies using realistic two nucleon potentials, and in certain positive energy intervals, these complex conjugated pairs indeed appear in the Sturmian spectrum. However, it is demonstrated that it is possible to recombine the complex conjugate pairs and corresponding states into a new, (and useful) pair of real eigenvalues and eigenstates with which of effect separable expansions of the (real) two nucleon reactance matrices. 8 refs

  9. Complex conjugate pairs in stationary Sturmian eigenstates

    International Nuclear Information System (INIS)

    Sturmian eigenstates specified by stationary scattering boundary conditions are particularly useful in contexts such as forming simple separable two nucleon t matrices, and are determined via solution of generalized eigenvalue equation using real and symmetric matrices. In general, the spectrum of such an equation may contain complex eigenvalues. But to each complex eigenvalue there is a corresponding conjugate partner. In studies using realistic nucleon-nucleon potentials, and in certain positive energy intervals, these complex conjugated pairs indeed appear in the Sturmian spectrum. However, as we demonstrate herein, it is possible to recombine the complex conjugate pairs and corresponding states into a new, sign-definite pair of real quantities with which to effect separable expansions of the (real) nucleon-nucleon reactance matrices

  10. Triplex glue by synthesizing conjugated flexible intercalators.

    Science.gov (United States)

    Pedersen, Erik B; Osman, Amany M A; Globisch, Daniel; Paramasivam, Manikandan; Cogoi, Susanna; Bomholt, Niels; Jørgensen, Per T; Xodo, Luigi E; Filichev, Vyacheslav V

    2008-01-01

    Bulge insertions of conjugated intercalators into the DNA triplex structure are found to give a dramatic contribution to the triplex stability. On the other hand insertions of conjugated intercalators are found to diminish quadruplex structures and in this way breaking down the self association of G-rich oligonucleotides under physiologically potassium ion conditions. A large number of intercalators are described here and they all result in dramatic increases of thermal stability of the corresponding triplexes. Another interesting aspect of conjugated intercalators is their use for assembling alternate strand triplexes. Targeting of neighbouring purine sequences on each their strand in the duplex DNA is a challenge for the 5'- 5' connectivity of the TFOs because of a large distance between the 5'-ends. The intercalator approach offers a linkage with the proper combination of flexibility and rigidity to produce alternate strand triplexes with higher stability than a similar wild type triplex of the same total length. PMID:18776241

  11. Conjugate Meningococcal Vaccines Development: GSK Biologicals Experience

    Directory of Open Access Journals (Sweden)

    Jacqueline M. Miller

    2011-01-01

    Full Text Available Meningococcal diseases are serious threats to global health, and new vaccines specifically tailored to meet the age-related needs of various geographical areas are required. This paper focuses on the meningococcal conjugate vaccines developed by GSK Biologicals. Two combined conjugate vaccines were developed to help protect infants and young children in countries where the incidence of meningococcal serogroup C or serogroup C and Y disease is important: Hib-MenC-TT vaccine, which offers protection against Haemophilus influenzae type b and Neisseria meningitidis serogroup C diseases, is approved in several countries; and Hib-MenCY-TT vaccine, which adds N. meningitidis serogroup Y antigen, is currently in the final stages of development. Additionally, a tetravalent conjugate vaccine (MenACWY-TT designed to help protect against four meningococcal serogroups is presently being evaluated for global use in all age groups. All of these vaccines were shown to be highly immunogenic and to have clinically acceptable safety profiles.

  12. Tight-binding treatment of conjugated polymers

    DEFF Research Database (Denmark)

    Lynge, Thomas Bastholm

    This PhD thesis concerns conjugated polymers which constitute a constantly growing research area. Today, among other things, conjugated polymers play a role in plastic based solar cells, photodetectors and light emitting diodes, and even today such plastic-based components constitute an alternative...... of tomorrow. This thesis specifically treats the three conjugated polymers trans-polyacetylene (tPA), poly(para-phenylene) (PPP) and poly(para-phe\\-nylene vinylene) (PPV). The present results, which are derived within the tight-binding model, are divided into two parts. In one part, analytic results...... are derived for the optical properties of the polymers expressed in terms of the optical susceptibility both in the presence and in the absence of a static electric field. In the other part, the cumputationally efficient Density Functional-based Tight-Binding (DFTB) model is applied to the description...

  13. Conjugate gradient algorithms using multiple recursions

    Energy Technology Data Exchange (ETDEWEB)

    Barth, T.; Manteuffel, T.

    1996-12-31

    Much is already known about when a conjugate gradient method can be implemented with short recursions for the direction vectors. The work done in 1984 by Faber and Manteuffel gave necessary and sufficient conditions on the iteration matrix A, in order for a conjugate gradient method to be implemented with a single recursion of a certain form. However, this form does not take into account all possible recursions. This became evident when Jagels and Reichel used an algorithm of Gragg for unitary matrices to demonstrate that the class of matrices for which a practical conjugate gradient algorithm exists can be extended to include unitary and shifted unitary matrices. The implementation uses short double recursions for the direction vectors. This motivates the study of multiple recursion algorithms.

  14. Conjugation in hydrogen-bonded systems

    CERN Document Server

    Novakovskaya, Yulia V

    2012-01-01

    Analysis of the electron density distribution in clusters composed of hydrogen fluoride, water, and ammonia molecules, especially within the hydrogen-bond domains, reveals the existence of both \\sigma- and \\pi-binding between molecules. The \\sigma-kind density distribution determines the mutual orientation of molecules. A \\pi-system may be delocalized conjugated, which provides additional stabilization of molecular clusters. In those clusters where the sequence of hydrogen bonds is not planar, a peculiar kind of \\pi-conjugation exists. HF anion and H5O2 cation are characterized by quasi-triple bonds between the electronegative atoms. The most long-lived species stabilized by delocalized \\pi-binding are rings and open or closed hoops composed of fused rings. It is conjugated \\pi-system that determines cooperativity phenomenon.

  15. Phase conjugation of high energy lasers.

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, David E; Valley, Michael T.; Atherton, Briggs W.; Bigman, Verle Howard; Boye, Lydia Ann; Broyles, Robin Scott; Kimmel, Mark W.; Law, Ryan J.; Yoder, James R.

    2013-01-01

    In this report we explore claims that phase conjugation of high energy lasers by stimulated Brillouin scattering (SBS) can compensate optical aberrations associated with severely distorted laser amplifier media and aberrations induced by the atmosphere. The SBS media tested was a gas cell pressurized up to 300 psi with SF6 or Xe or both. The laser was a 10 Hz, 3J, Q-switched Nd:YAG with 25 ns wide pulses. Atmospheric aberrations were created with space heaters, helium jets and phase plates designed with a Kolmogorov turbulence spectrum characterized by a Fried parameter, ro , ranging from 0.6 6.0 mm. Phase conjugate tests in the laboratory were conducted without amplification. For the strongest aberrations, D/ro ~ 20, created by combining the space heaters with the phase plate, the Strehl ratio was degraded by a factor of ~50. Phase conjugation in SF6 restored the peak focusable intensity to about 30% of the original laser. Phase conjugate tests at the outdoor laser range were conducted with laser amplifiers providing gain in combination with the SBS cell. A large 600,000 BTU kerosene space heater was used to create turbulence along the beam path. An atmospheric structure factor of Cn2 = 5x10-13 m2/3 caused the illumination beam to expand to a diameter 250mm and overfill the receiver. The phase conjugate amplified return could successfully be targeted back onto glints 5mm in diameter. Use of a lenslet arrays to lower the peak focusable intensity in the SBS cell failed to produce a useful phase conjugate beam; The Strehl ratio was degraded with multiple random lobes instead of a single focus. I will review literature results which show how multiple beams can be coherently combined by SBS when a confocal reflecting geometry is used to focus the laser in the SBS cell.

  16. Synthesis of cyanopyridine based conjugated polymer

    Directory of Open Access Journals (Sweden)

    B. Hemavathi

    2016-06-01

    Full Text Available This data file contains the detailed synthetic procedure for the synthesis of two new cyanopyridine based conjugated polymer P1 and P2 along with the synthesis of its monomers. The synthesised polymers can be used for electroluminescence and photovoltaic (PV application. The physical data of the polymers are provided in this data file along with the morphological data of the polymer thin films. The data provided here are in association with the research article entitled ‘Cyanopyridine based conjugated polymer-synthesis and characterisation’ (Hemavathi et al., 2015 [3].

  17. Conjugated polymers as actuators: modes of actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2007-01-01

    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed...

  18. Conjugated Polymers as Actuators: Modes of Actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed...

  19. Dynamics of Photogenerated Polarons in Conjugated Polymers

    Science.gov (United States)

    An, Z.; Wu, C. Q.; Sun, X.

    2004-11-01

    Within a tight-binding electron-phonon interacting model, we investigate the dynamics of photoexcitations to address the generation mechanism of charged polarons in conjugated polymers by using a nonadiabatic evolution method. Besides the neutral polaron exciton which is well known, we identify a novel product of lattice dynamic relaxation from the photoexcited states in a few hundreds of femtoseconds, which is a mixed state composed of both charged polarons and neutral excitons. Our results show that the charged polarons are generated directly with a yield of about 25%, which is independent of the excitation energies, in good agreement with results from experiments. Effects of the conjugation length are also discussed.

  20. Theoretical study of conjugated porphyrin polymers

    DEFF Research Database (Denmark)

    Pedersen, T.G.; Lynge, T.B.; Kristensen, P.K.;

    2005-01-01

    for these applications. From a theoretical analysis of excitons in long metalloporphyrin chains, we demonstrate that the binding energy is much lower than in usual conjugated polymers. Our calculated absorption spectra are in good agreement with measurements. (c) 2004 Elsevier B.V. All rights reserved.......The optical gap of conjugated triply linked porphyrin chains is exceptionally low (similar to 0.5 eV). Hence, such chains are candidates for organic infrared detectors and solar cells harvesting the infrared part of the solar spectrum. However, a low exciton binding energy is required...

  1. Conjugate metamaterials and the perfect lens

    CERN Document Server

    Xu, Yadong; Xu, Lin; Chen, Huanyang

    2015-01-01

    In this letter, we show how transformation optics makes it possible to design what we call conjugate metamaterials. We show that these materials can also serve as substrates for making a subwavelength-resolution lens. The so-called "perfect lens", which is a lens that could focus all components of light (including propagating and evanescent waves), can be regarded as a limiting case, in which the respective conjugate metamaterials approach the characteristics of left-handed metamaterials, which have a negative refractive index.

  2. Conjugate Gradient Methods with Armijo-type Line Searches

    Institute of Scientific and Technical Information of China (English)

    Yu-Hong DAI

    2002-01-01

    Two Armijo-type line searches are proposed in this paper for nonlinear conjugate gradient methods.Under these line searches, global convergence results are established for several famous conjugate gradient method.

  3. Interaction of antithrombin III with preadsorbed albumin-heparin conjugates

    OpenAIRE

    Hennink, W.E.; Ebert, C.D.; Kim, S. W.; Breemhaar, W.; Bantjes, A.; Feijen, J.

    1984-01-01

    The adsorption of antithrombin III (AT III) onto polystyrene surfaces preadsorbed with albumin or albuminheparin conjugates was studied using a two step enzyme immuno assay. When AT III-buffer solutions were used, the highest adsorption values were measured on high affinity albumin-heparin conjugate pretreated surfaces. Less AT III adsorption was found on nonfractionated albumin-heparin conjugate preadsorbed surfaces. AT III adsorption could also be detected on low affinity conjugate and albu...

  4. Biocatalytic Synthesis of Fluorescent Conjugated Indole Oligomers

    Directory of Open Access Journals (Sweden)

    Ryan M. Bouldin

    2014-12-01

    Full Text Available Fluorescent conjugated materials exhibiting reasonable biocompatibility that are capable of interacting with biological molecules are of interest for bio-sensing and imaging applications. Traditional approaches do not allow for the synthesis of conjugated materials in the presence of biologically relevant substrates. Further conjugated polymers synthesized using conventional methods are doped and not fluorescent. Here we explore the possibility of synthesizing fluorescent oligomers of indole using enzymes as catalyst under mild conditions. The peroxidase catalyzed coupling reaction presented here creates a photoluminescent material that allows for direct utilization (without purification and separation of the dopant in biosensing applications. The polymerization reaction proceeds smoothly in just deionized water and ethanol. Monitoring of the absorption and fluorescence spectra over one hour shows that the concentration of both absorbing and emitting species grows steadily over time. The presence of anionic buffers and templates is shown to effectively retard the development of light emitting species and instead leads to the formation of an electrically doped conjugated polymer. Structural characterization through FTIR and 1H-NMR analysis suggests that the oligomer is coupled through the 2 and 3 positions on the indole ring.

  5. Women experiencing the intergenerationality of conjugal violence

    Directory of Open Access Journals (Sweden)

    Gilvânia Patrícia do Nascimento Paixão

    2015-10-01

    Full Text Available Objective: to analyze the family relationship, in childhood and adolescence, of women who experience conjugal violence.Method: qualitative study. Interviews were held with 19 women, who were experiencing conjugal violence, and who were resident in a community in Salvador, Bahia, Brazil. The project was approved by the Research Ethics Committee (N. 42/2011.Results: the data was organized using the Discourse of the Collective Subject, identifying the summary central ideas: they witnessed violence between their parents; they suffered repercussions from the violence between their parents: they were angry about the mother's submission to her partner; and they reproduced the conjugal violence. The discourse showed that the women witnessed, in childhood and adolescence, violence between their parents, and were injured both physically and psychologically. As a result of the mother's submission, feelings of anger arose in the children. However, in the adult phase of their own lives, they noticed that their conjugal life resembled that of their parents, reproducing the violence.Conclusion: investment is necessary in strategies designed to break inter-generational violence, and the health professionals are important in this process, as it is a phenomenon with repercussions in health. Because they work in the Family Health Strategy, which focuses on the prevention of harm and illness, health promotion and interdepartmentality, the nurses are essential in the process of preventing and confronting this phenomenon.

  6. Stochastic differential equations used to model conjugation

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber; Christiansen, Lasse Engbo

    Stochastic differential equations (SDEs) are used to model horizontal transfer of antibiotic resis- tance by conjugation. The model describes the concentration of donor, recipient, transconjugants and substrate. The strength of the SDE model over the traditional ODE models is that the noise can...

  7. Charge Conjugation in the Galilean Limit

    OpenAIRE

    Socolovsky, Miguel

    2006-01-01

    Strictly working in the framework of the nonrelativistic quantum mechanics of a spin 1/2 particle coupled to an external electromagnetic field, we show, by explicit construction, the existence of a charge conjugation operator matrix which defines the corresponding antiparticle wave function and leads to the galilean and gauge invariant Schroedinger-Pauli equation satisfied by it.

  8. Conjugate Function Method for Numerical Conformal Mappings

    CERN Document Server

    Hakula, Harri; Rasila, Antti

    2011-01-01

    We present a method for numerical computation of conformal mappings from simply or doubly connected domains onto so-called canonical domains, which in our case are rectangles or annuli. The method is based on conjugate harmonic functions and properties of quadrilaterals. Several numerical examples are given.

  9. Predicting the optical gap of conjugated systems

    Science.gov (United States)

    Botelho, Andre Leitao

    The adapted Su-Schrieffer-Heeger model is developed in this work as a tool for in silico prediction of the optical gap of pi-conjugated systems for photovoltaic applications. Full transferability of the model ensures reliable predictive power - excellent agreement with 180 independent experimental data points covering virtually all existing conjugated system types with an accuracy exceeding the time-dependent density functional theory, one of the most accurate first-principles methods. Insights on the structure-property relation of conjugated systems obtained from the model lead to guiding rules for optical gap design: 1) fusing aromatic rings parallel to the conjugated path does not significantly lower the optical gap, 2) fusing rings perpendicularly lowers the optical gap of the monomer, but has a reduced benefit from polymerization, and 3) copolymers take advantage of the lower optical gap of perpendicular fused rings and benefit from further optical gap reduction through added parallel fused rings as electronic communicators. A copolymer of parallel and perpendicular benzodithiophenes, differing only in sulfur atom locations, is proposed as a candidate to achieve the optimal 1.2 eV donor optical gap for organic photovoltaics. For small-molecule organic photovoltaics, substituting the end pairs of carbon atoms on pentacene with sulfur atoms is predicted to lower the optical gap from 1.8 eV to 1.1 eV. Furthermore, the model offers an improvement of orders of magnitude in the computational efficiency over commonly used first-principles tools.

  10. Conjugate Problems in Convective Heat Transfer: Review

    Directory of Open Access Journals (Sweden)

    Abram Dorfman

    2009-01-01

    Full Text Available A review of conjugate convective heat transfer problems solved during the early and current time of development of this modern approach is presented. The discussion is based on analytical solutions of selected typical relatively simple conjugate problems including steady-state and transient processes, thermal material treatment, and heat and mass transfer in drying. This brief survey is accompanied by the list of almost two hundred publications considering application of different more and less complex analytical and numerical conjugate models for simulating technology processes and industrial devices from aerospace systems to food production. The references are combined in the groups of works studying similar problems so that each of the groups corresponds to one of selected analytical solutions considered in detail. Such structure of review gives the reader the understanding of early and current situation in conjugate convective heat transfer modeling and makes possible to use the information presented as an introduction to this area on the one hand, and to find more complicated publications of interest on the other hand.

  11. New Antibody Conjugates in Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Serengulam V. Govindan

    2010-01-01

    Full Text Available Targeting of radiation, drugs, and protein toxins to cancers selectively with monoclonal antibodies (MAbs has been a topic of considerable interest and an area of continued development. Radioimmunotherapy (RAIT of lymphoma using directly labeled MAbs is of current interest after approval of two radiolabeled anti-CD20 MAbs, as illustrated with the near 100% overall response rate obtained in a recent clinical trial using an investigational radiolabeled anti-CD22 MAb, 90Y-epratuzumab. The advantage of pretargeted RAIT over directly labeled MAbs is continuing to be validated in preclinical models of lymphoma and solid tumors. Importantly, the advantages of combining RAIT with radiation sensitizers, with immunotherapy, or a drug conjugate targeting a different antigen are being studied clinically and preclinically. The area of drug-conjugated antibodies is progressing with encouraging data published for the trastuzumab-DM1 conjugate in a phase I clinical trial in HER2-positive breast cancer. The Dock-and-Lock platform technology has contributed to the design and the evaluation of complex antibody-cytokine and antibody-toxin conjugates. This review describes the advances made in these areas, with illustrations taken from advances made in the authors' institutions.

  12. Conjugate problems in convective heat transfer

    CERN Document Server

    Dorfman, Abram S

    2009-01-01

    The conjugate heat transfer (CHT) problem takes into account the thermal interaction between a body and fluid flowing over or through it, a key consideration in both mechanical and aerospace engineering. Presenting more than 100 solutions of non-isothermal and CHT problems, this title considers the approximate solutions of CHT problems.

  13. Compositions for directed alignment of conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinsang; Kim, Bong-Gi; Jeong, Eun Jeong

    2016-04-19

    Conjugated polymers (CPs) achieve directed alignment along an applied flow field and a dichroic ratio of as high as 16.67 in emission from well-aligned thin films and fully realized anisotropic optoelectronic properties of CPs in field-effect transistor (FET).

  14. Bacillus thuringiensis Conjugation in Simulated Microgravity

    Science.gov (United States)

    Beuls, Elise; van Houdt, Rob; Leys, Natalie; Dijkstra, Camelia; Larkin, Oliver; Mahillon, Jacques

    2009-10-01

    Spaceflight experiments have suggested a possible effect of microgravity on the plasmid transfer among strains of the Gram-positive Bacillus thuringiensis, as opposed to no effect recorded for Gram-negative conjugation. To investigate these potential effects in a more affordable experimental setup, three ground-based microgravity simulators were tested: the Rotating Wall Vessel (RWV), the Random Positioning Machine (RPM), and a superconducting magnet. The bacterial conjugative system consisted in biparental matings between two B. thuringiensis strains, where the transfer frequencies of the conjugative plasmid pAW63 and its ability to mobilize the nonconjugative plasmid pUB110 were assessed. Specifically, potential plasmid transfers in a 0-g position (simulated microgravity) were compared to those obtained under 1-g (normal gravity) condition in each device. Statistical analyses revealed no significant difference in the conjugative and mobilizable transfer frequencies between the three different simulated microgravitational conditions and our standard laboratory condition. These important ground-based observations emphasize the fact that, though no stimulation of plasmid transfer was observed, no inhibition was observed either. In the case of Gram-positive bacteria, this ability to exchange plasmids in weightlessness, as occurs under Earth's conditions, should be seen as particularly relevant in the scope of spread of antibiotic resistances and bacterial virulence.

  15. Hyperbranched: a universal conjugated polymer platform.

    Science.gov (United States)

    Tolosa, Juan; Kub, Chris; Bunz, Uwe H F

    2009-01-01

    Out on a limb: Sonogashira coupling of a suitable AB(2) monomer containing two iodine and one alkyne group forms a hyperbranched conjugated polymer that is studded with iodine end groups (see picture: I purple). These iodine groups are a perfect handle for convenient, efficient, and high-yielding post-functionalization to access hyperbranched, fluorescent poly(phenyleneethynylene)s. PMID:19373821

  16. Conjugated Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2007-01-01

    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1...

  17. Continuous flow synthesis of conjugated polymers.

    Science.gov (United States)

    Seyler, Helga; Jones, David J; Holmes, Andrew B; Wong, Wallace W H

    2012-02-01

    A selection of conjugated polymers, widely studied in organic electronics, was synthesised using continuous flow methodology. As a result of superior heat transfer and reagent control, excellent polymer molecular mass distributions were achieved in significantly reduced reaction times compared to conventional batch reactions.

  18. Conjugal Succession and the American Kinship System.

    Science.gov (United States)

    Furstenberg, Frank F., Jr.

    Although not the preferred type of family formation, conjugal succession is now an accepted, if not expected, alternative to continuous marriage in the United States. This new trend appears to be related to a shift in the meaning of matrimony. Previously, marriage was part of a cultural pattern of transitions and as such was closely timed to…

  19. Meningococcal conjugate vaccines: optimizing global impact

    Directory of Open Access Journals (Sweden)

    Terranella A

    2011-09-01

    Full Text Available Andrew Terranella1,2, Amanda Cohn2, Thomas Clark2 1Epidemic Intelligence Service, Division of Applied Sciences, Scientific Education and Professional Development Program Office, 2Meningitis and Vaccine Preventable Diseases Branch, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA Abstract: Meningococcal conjugate vaccines have several advantages over polysaccharide vaccines, including the ability to induce greater antibody persistence, avidity, immunologic memory, and herd immunity. Since 1999, meningococcal conjugate vaccine programs have been established across the globe. Many of these vaccination programs have resulted in significant decline in meningococcal disease in several countries. Recent introduction of serogroup A conjugate vaccine in Africa offers the potential to eliminate meningococcal disease as a public health problem in Africa. However, the duration of immune response and the development of widespread herd immunity in the population remain important questions for meningococcal vaccine programs. Because of the unique epidemiology of meningococcal disease around the world, the optimal vaccination strategy for long-term disease prevention will vary by country. Keywords: conjugate vaccine, meningitis, meningococcal vaccine, meningococcal disease

  20. Synthesis of Indomethacin Conjugates with D-Glucosamine

    Institute of Scientific and Technical Information of China (English)

    Yi Chun ZHANG; Ying Xia LI; Hua Shi GUAN

    2005-01-01

    Two series of indomethacin conjugates with D-glucosamine were prepared with the objectives of reducing ulcerogenic potency, increasing the bioavailability of indomethacin and exerting the coordinative effects on osteoarthritis. The structures of the conjugates were identified by 1H NMR and 13C NMR. The ester conjugates inhibited edema as potent as indomethacin.

  1. Conjugated Educational System: Notion, Structure, Educational Potential 

    OpenAIRE

    Andrei A. Ostapenko; Dar'ya S. Tkach

    2012-01-01

    The article indicates the ways to decrease risk from teenagers and youth’s growing-up in today’s Russia by development of fundamental models of conjugated educational systems and their mass implementation in educational practice, introduces the notion of “conjugated educational system” for scientific use, describes types of conjugation and educational results of submitted models use.

  2. Resolution of Digitized Conjugate Tooth-Face Surface Based on the Theory of Digitized Conjugate Surfaces

    Institute of Scientific and Technical Information of China (English)

    XIAO Lai-yuan; LIAO Dao-xun; YI Chuan-yun

    2004-01-01

    According to the principle of meshing engagement and the theory of the digitized conjugate surface, this paper applies the software Conjugater-l. 0 that is developed by ourselves to compute, respectivcly, the digitized conjugate curved surfaces of the straight-tooth surface and drum-tooth surface,which will establish the theoretical and technical foundation for digitized engaging analysis, simulation, and digitized manufacturing technology of the diversified gears.

  3. Application of optical phase conjugation to plasma diagnostics (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Jahoda, F.C.; Anderson, B.T.; Forman, P.R.; Weber, P.G.

    1985-05-01

    Several possibilities for plasma diagnostics provided by optical phase conjugation and, in particular, self-pumped phase conjugation in barium titanate (BaTiO/sub 3/) are discussed. These include placing a plasma within a dye laser cavity equipped with a phase conjugate mirror for intracavity absorption measurements, time differential refractometry with high spatial resolution, and simplified real-time holographic interferometry. The principles of phase conjugation with particular reference to photorefractive media and the special advantages of self-pumped phase conjugation are reviewed prior to the discussion of the applications. Distinctions are made in the applications between those for which photorefractive conjugators are essential and those for which they only offer experimental simplification relative to other types of phase conjugators.

  4. Highly sensitive biosensors based on water-soluble conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    XU Hui; WU Haiping; FAN Chunhai; LI Wenxin; ZHANG Zhizhou; HE Lin

    2004-01-01

    Conjugated, conductive polymers are a kind of important organic macromolecules, which has found applications in a variety of areas. The application of conjugated polymers in developing fluorescent biosensors represents the merge of polymer sciences and biological sciences. Conjugated polymers are very good light harvesters as well as fluorescent polymers, and they are also "molecular wires". Through elaborate designs, these important features, i.e. efficient light harvesting and electron/energy transfer, can be used as signal amplification in fluorescent biosensors. This might significantly improve the sensitivity of conjugated polymer-based biosensors. In this article, we reviewed the application of conjugated polymers, via either electron transfer or energy transfer, to detections of gene targets, antibodies or enzymes. We also reviewed recent efforts in conjugated polymer-based solid-state sensor designs as well as chip-based multiple target detection. Possible directions in this conjugated polymer-based biosensor area are also discussed.

  5. PRINCIPLE AND TRANSMISSION TECHNOLOGY OF BERTRAND CONJUGATE SURFACES

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhenyun; CHEN Houjun; LIU Jian

    2006-01-01

    Bertrand surface is presented by abstracting and subliming the common characteristic of the usual surfaces including rotational surfaces, developable surfaces, normal circular-arc surfaces,etc. Basic characteristic of Bertrand surface is that normals along generator are coplanar. Bertrand conjugate principle is studied and its basic characteristic is that the instantaneous contact line between a pair of Bertrand conjugate surfaces is generator. Bertrand conjugate can be divided into three kinds of typical conjugation forms in terms of the generators that are general plane curve, circular-arc and straight line. Basic conjugate condition is given respectively, and structure condition, which reflects transmission forms and directrix characteristic of this kind of conjugation, is researched. As typical engineering application of Bertrand conjugate surface principle, transmission technology of loxodromic-type normal circular-arc bevel gear is studied.

  6. Discrete modelling of bacterial conjugation dynamics

    CERN Document Server

    Goni-Moreno, Angel

    2012-01-01

    In bacterial populations, cells are able to cooperate in order to yield complex collective functionalities. Interest in population-level cellular behaviour is increasing, due to both our expanding knowledge of the underlying biological principles, and the growing range of possible applications for engineered microbial consortia. Researchers in the field of synthetic biology - the application of engineering principles to living systems - have, for example, recently shown how useful decision-making circuits may be distributed across a bacterial population. The ability of cells to interact through small signalling molecules (a mechanism known as it quorum sensing) is the basis for the majority of existing engineered systems. However, horizontal gene transfer (or conjugation) offers the possibility of cells exchanging messages (using DNA) that are much more information-rich. The potential of engineering this conjugation mechanism to suit specific goals will guide future developments in this area. Motivated by a l...

  7. Development of a conjugate heat transfer solver

    OpenAIRE

    Al-Qubeissi, Mansour

    2013-01-01

    The current research study presents a numerical approach in modelling the conjugate heat transfer system of the gas-turbine rotating discs-cavities. The work was undertaken to understand such phenomena and, more specifically, to numerically investigate the thermal interactions in rotating discs-cavities. The developed solver is capable of dealing with complex heat transfer problems, such as unsteady three-dimensional compressible rotating-flows. The development was based on integrating...

  8. Functionalized conjugated polyelectrolytes design and biomedical applications

    CERN Document Server

    Wang, Shu

    2013-01-01

    Functionalized Conjugated Polyelectrolytes presents a comprehensive review of these polyelectrolytes and their biomedical applications. Basic aspects like molecular design and optoelectronic properties are covered in the first chapter. Emphasis is placed on the various applications including sensing (chemical and biological), disease diagnosis, cell imaging, drug/gene delivery and disease treatment. This book explores a multi-disciplinary topic of interest to researchers working in the fields of chemistry, materials, biology and medicine. It also offers an integrated perspective on both basic

  9. Synchronization in nonlinear oscillators with conjugate coupling

    OpenAIRE

    Han, Wenchen; Zhang, Mei; Yang, Junzhong

    2014-01-01

    In this work, we investigate the synchronization in oscillators with conjugate coupling in which oscillators interact via dissimilar variables. The synchronous dynamics and its stability are investigated theoretically and numerically. We ?nd that the synchronous dynamics and its stability are dependent on both coupling scheme and the coupling constant. We also ?nd that the synchronization may be independent of the number of oscillators. Numerical demonstrations with Lorenz oscillators are pro...

  10. Applications of Conjugated Polymers to DNA Sensing

    Institute of Scientific and Technical Information of China (English)

    Jadranka; Travas-Sejdic; Christian; Soeller

    2007-01-01

    1 Results Detection of biomolecules relies on a highly specific recognition event between an analyte biomolecule and a probe that is often closely connected or integrated within a sensor transducer element to provide a suitable signal. More widespread application of gene detection on a routine basis demands the development of a new generation of gene sensors that are fast, reliable and cost-effective.Conjugated polymers (CPs) have been shown to be a versatile substrate for DNA sensor construction, where...

  11. Conjugated Linoleic Acid: good or bad nutrient

    Directory of Open Access Journals (Sweden)

    Gonçalves Daniela C

    2010-10-01

    Full Text Available Abstract Conjugated linoleic acid (CLA is a class of 28 positional and geometric isomers of linoleic acid octadecadienoic.Currently, it has been described many benefits related to the supplementation of CLA in animals and humans, as in the treatment of cancer, oxidative stress, in atherosclerosis, in bone formation and composition in obesity, in diabetes and the immune system. However, our results show that, CLA appears to be not a good supplement in patients with cachexia.

  12. Spectral phase conjugation via extended phase matching

    OpenAIRE

    Tsang, Mankei

    2005-01-01

    It is shown that the copropagating three-wave-mixing parametric process, with appropriate type-II extended phase matching and pumped with a short second-harmonic pulse, can perform spectral phase conjugation and parametric amplification, which shows a threshold behavior analogous to backward wave oscillation. The process is also analyzed in the Heisenberg picture, which predicts a spontaneous parametric down conversion rate in agreement with the experimental result reported by Kuzucu et al. [...

  13. Solventless processing of conjugated polymers - a review

    OpenAIRE

    Brandão, Lúcia; Viana, Júlio; David G. Bucknall; Bernardo, Gabriel

    2014-01-01

    The molecular mobility of polymers in their solid or molten states allows their processing without the need for toxic, “non-friendly” solvents. In this work, the main features of solvent-free processing methods applied to conjugated polymers are reviewed taking into consideration that these materials are largely used in a broad range of (opto-)electronic applications, including organic field-effect transistors, polymer light-emitting diodes and polymer photovoltaic devices. This review addres...

  14. Peptide conjugation: before or after nanoparticle formation?

    Science.gov (United States)

    Valetti, Sabrina; Mura, Simona; Noiray, Magali; Arpicco, Silvia; Dosio, Franco; Vergnaud, Juliette; Desmaële, Didier; Stella, Barbara; Couvreur, Patrick

    2014-11-19

    We report herein a detailed study concerning the impact of different bioconjugation and nanoformulation strategies on the in vitro targeting ability of peptide-decorated squalenoyl gemcitabine (SQdFdC) nanoparticles (NPs). NPs have been functionalized with the CKAAKN peptide, previously identified as an efficient homing device within the pancreatic pathological microenvironment. Two approaches have been followed: (i) either the CKAAKN peptide was directly conjugated at the surface of preformed SQdFdC nanoparticles (conjugation after NP formation) or (ii) it was first reacted with a maleimide squalenoyl derivative before the resulting bioconjugate was co-nanoprecipitated with SQdFdC to form the peptide-decorated NPs (conjugation before NP formation). NPs were characterized with respect to mean diameter, zeta potential, and stability over time. Then, their specific interaction with the sFRP-4 protein was evaluated by surface plasmon resonance. Although both synthetic strategies allowed us to formulate NPs able to interact with the corresponding receptor, enhanced target binding and better specific avidity were observed with CKAAKN-NPs functionalized before NP formation. These NPs displayed the highest cell uptake and cytotoxicity in an in vitro model of human MIA Paca-2 pancreatic cancer cells.

  15. Structural investigation of PEG-fibrinogen conjugates.

    Science.gov (United States)

    Frisman, Ilya; Orbach, Ron; Seliktar, Dror; Bianco-Peled, Havazelet

    2010-01-01

    Controllable bio-synthetic polymeric hydrogels made from fibrinogen-poly(ethylene glycol) adducts have been successfully employed in tissue engineering. The structural consequences of PEG conjugation to fibrinogen (i.e., PEGylation) in such a hydrogel network are not fully understood. The current investigation details the structural alterations caused to the reduced fibrinogen polypeptides by the covalent attachment of linear or branched PEG chains. The structure of PEGylated fibrinogen polypeptides were comprehensively characterized using small angle X-ray scattering, light scattering, and cryo-transmission electron microscopy. These characterizations concur that the bio-synthetic hybrids self-assemble into elongated objects, having a protein core of about 50 A in diameter decorated with multiple PEG chains. Conjugates with branched PEG chains were shorter, and have lower average molecular weight compared to conjugates with linear chains. The diameter of the protein core of both samples was similar, suggesting a tail-to-head aggregation of the PEGylated fibrinogen polypeptide. A more complete understanding of this unique structural arrangement can provide further insight into the full extent of biofunctional accessibility in a biomaterial that combines the advantages of synthetic polymers with bioactive proteins. PMID:19693654

  16. Oligonucleotide conjugates - Candidates for gene silencing therapeutics.

    Science.gov (United States)

    Gooding, Matt; Malhotra, Meenakshi; Evans, James C; Darcy, Raphael; O'Driscoll, Caitriona M

    2016-10-01

    The potential therapeutic and diagnostic applications of oligonucleotides (ONs) have attracted great attention in recent years. The capability of ONs to selectively inhibit target genes through antisense and RNA interference mechanisms, without causing un-intended sideeffects has led them to be investigated for various biomedical applications, especially for the treatment of viral diseases and cancer. In recent years, many researchers have focused on enhancing the stability and target specificity of ONs by encapsulating/complexing them with polymers or lipid chains to formulate nanoparticles/nanocomplexes/micelles. Also, chemical modification of nucleic acids has emerged as an alternative to impart stability to ONs against nucleases and other degrading enzymes and proteins found in blood. In addition to chemically modifying the nucleic acids directly, another strategy that has emerged, involves conjugating polymers/peptide/aptamers/antibodies/proteins, preferably to the sense strand (3'end) of siRNAs. Conjugation to the siRNA not only enhances the stability and targeting specificity of the siRNA, but also allows for the development of self-administering siRNA formulations, with a much smaller size than what is usually observed for nanoparticle (∼200nm). This review concentrates mainly on approaches and studies involving ON-conjugates for biomedical applications. PMID:27521696

  17. Cancer Chemopreventive Ability of Conjugated Linolenic Acids

    Directory of Open Access Journals (Sweden)

    Kazuo Miyashita

    2011-11-01

    Full Text Available Conjugated fatty acids (CFA have received increased interest because of their beneficial effects on human health, including preventing cancer development. Conjugated linoleic acids (CLA are such CFA, and have been reviewed extensively for their multiple biological activities. In contrast to other types of CFAs including CLA that are found at low concentrations (less than 1% in natural products, conjugated linolenic acids (CLN are the only CFAs that occur in higher quantities in natural products. Some plant seeds contain a considerably high concentration of CLN (30 to 70 wt% lipid. Our research group has screened CLN from different plant seed oils to determine their cancer chemopreventive ability. This review describes the physiological functions of CLN isomers that occur in certain plant seeds. CLN are able to induce apoptosis through decrease of Bcl-2 protein in certain human cancer cell lines, increase expression of peroxisome proliferator-activated receptor (PPAR-γ, and up-regulate gene expression of p53. Findings in our preclinical animal studies have indicated that feeding with CLN resulted in inhibition of colorectal tumorigenesis through modulation of apoptosis and expression of PPARγ and p53. In this review, we summarize chemopreventive efficacy of CLN against cancer development, especially colorectal cancer.

  18. Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis.

    Science.gov (United States)

    Topuzogullari, Murat; Cakir Koc, Rabia; Dincer Isoglu, Sevil; Bagirova, Melahat; Akdeste, Zeynep; Elcicek, Serhat; Oztel, Olga N; Yesilkir Baydar, Serap; Canim Ates, Sezen; Allahverdiyev, Adil M

    2013-01-01

    Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential. PMID:23731716

  19. Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis.

    Science.gov (United States)

    Topuzogullari, Murat; Cakir Koc, Rabia; Dincer Isoglu, Sevil; Bagirova, Melahat; Akdeste, Zeynep; Elcicek, Serhat; Oztel, Olga N; Yesilkir Baydar, Serap; Canim Ates, Sezen; Allahverdiyev, Adil M

    2013-06-03

    Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential.

  20. Antibody Conjugates: From Heterogeneous Populations to Defined Reagents

    Directory of Open Access Journals (Sweden)

    Patrick Dennler

    2015-08-01

    Full Text Available Monoclonal antibodies (mAbs and their derivatives are currently the fastest growing class of therapeutics. Even if naked antibodies have proven their value as successful biopharmaceuticals, they suffer from some limitations. To overcome suboptimal therapeutic efficacy, immunoglobulins are conjugated with toxic payloads to form antibody drug conjugates (ADCs and with chelating systems bearing therapeutic radioisotopes to form radioimmunoconjugates (RICs. Besides their therapeutic applications, antibody conjugates are also extensively used for many in vitro assays. A broad variety of methods to functionalize antibodies with various payloads are currently available. The decision as to which conjugation method to use strongly depends on the final purpose of the antibody conjugate. Classical conjugation via amino acid residues is still the most common method to produce antibody conjugates and is suitable for most in vitro applications. In recent years, however, it has become evident that antibody conjugates, which are generated via site-specific conjugation techniques, possess distinct advantages with regard to in vivo properties. Here, we give a comprehensive overview on existing and emerging strategies for the production of covalent and non-covalent antibody conjugates.

  1. Dye linked conjugated homopolymers: using conjugated polymer electroluminescence to optically pump porphyrin-dye emission

    DEFF Research Database (Denmark)

    Nielsen, K.T.; Spanggaard, H.; Krebs, Frederik C

    2004-01-01

    Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were....... Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue...

  2. Co-conjugation vis-à-vis individual conjugation of α-amylase and glucoamylase for hydrolysis of starch.

    Science.gov (United States)

    Jadhav, Swati B; Singhal, Rekha S

    2013-10-15

    Two enzymes, α-amylase and glucoamylase have been individually and co-conjugated to pectin by covalent binding. Both the enzyme systems showed better thermal and pH stability over the free enzyme system with the complete retention of original activities. Mixture of individually conjugated enzymes showed lower inactivation rate constant with longer half life than the co-conjugated enzyme system. Individually conjugated enzymes showed an increase of 56.48 kJ/mole and 38.22 kJ/mole in activation energy for denaturation than the free enzymes and co-conjugated enzymes, respectively. Km as well as Vmax of individually and co-conjugated enzymes was found to be higher than the free enzymes. SDS-polyacrylamide gel electrophoresis confirmed the formation of conjugate and co-conjugate as evident by increased molecular weight. Both the enzyme systems were used for starch hydrolysis where individually conjugated enzymes showed highest release of glucose at 60 °C and pH 5.0 as compared to free and co-conjugated enzyme.

  3. Luminescence of a conjugated polymer containing europium (III) chelate

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Hao; Xie, Fang, E-mail: xiefang4498@126.com

    2013-12-15

    A europium (III) chelate has been incorporated in a conjugated polymer, poly-[2,2′-bipyridine-5,5′-diyl-(2,5-dihexyl-1,4-phenylene)]. From the absorbance and emission spectra measurement and using the Judd–Ofelt theory, an efficient energy transfer between the conjugated polymer and the europium (III) chelate has been confirmed. The luminescence lifetime of Eu{sup 3+} ion in the conjugated polymer is 0.352 ms and the emission cross section of this material is 3.11×10{sup −21} cm{sup 2}. -- Highlights: • A europium chelate has been incorporated in a conjugated polymer. • Energy transfer in the conjugated polymer containing europium chelate is efficient. • The conjugated polymer containing europium chelate is a promising optical material.

  4. Synthesis and characterization of HPMA copolymer-5-FU conjugates

    Institute of Scientific and Technical Information of China (English)

    Fang Yuan; Fu Chen; Qing Yu Xiang; Xuan Qin; Zhi Rong Zhang; Yuan Huang

    2008-01-01

    N-(2-Hydroxypropyl)methacrylamide copolymer-5-fluorouracil (PHPMA-FU)conjugates were synthesized by a novel and simplified synthetic mute,and characterized by UV,FTIR and HPLC analyses.The conjugated content of 5-fluorouracil (5-FU)was 3.41 ± 0.07 wt%.The stabilities of PHPMA-FU conjugates under different conditions were studied.The results showed that HPMA copolymer was a potential carrier for tumor-targeting delivery of 5-FU.

  5. Preparation and characterization of microspheres of albumin-heparin conjugates

    OpenAIRE

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Feijen, Jan

    1991-01-01

    Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form albumin-heparin microspheres. The composition of the conjugate was determined by amino acid analysis. The swelling properties of albumin-heparin microspheres were investigated as a function of pH and ionic stre...

  6. Design, synthesis, characterization and study of novel conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, W.

    1997-06-24

    After introducing the subject of conjugated polymers, the thesis has three sections each containing a literature survey, results and discussion, conclusions, and experimental methods on the following: synthesis, characterization of electroluminescent polymers containing conjugated aryl, olefinic, thiophene and acetylenic units and their studies for use in light-emitting diodes; synthesis, characterization and study of conjugated polymers containing silole unit in the main chain; and synthesis, characterization and study of silicon-bridged and butadiene-linked polythiophenes.

  7. Polylactide Conjugates of Camptothecin with Different Drug Release Abilities

    OpenAIRE

    Ewa Oledzka; Paweł Horeglad; Zuzanna Gruszczyńska; Andrzej Plichta; Grzegorz Nałęcz-Jawecki; Marcin Sobczak

    2014-01-01

    Camptothecin-polylactide conjugates (CMPT-PLA) were synthesized by covalent incorporation of CMPT into PLA of different microstructure, i.e., atactic PLA and atactic-block-isotactically enriched PLA (Pm = 0.79) via urethane bonds. The kinetic release of CPMT from CMPT-PLA conjugates, tested in vitro under different conditions, is possible in both cases and notably, strongly dependent on PLA microstructure. It shows that release properties of drug-PLA conjugates can be tailored by controlled ...

  8. Goat serums for fluorescent antibody conjugates to chlamydial antigens.

    OpenAIRE

    Tessler, J.

    1984-01-01

    Serums from goats hyperimmunized with Chlamydia psittaci consistently produce antichlamydial fluorescent antibody conjugate of high titer. The titer of the fluorescent antibody conjugate prepared from a given serum correlated well with the titer obtained by agar gel precipitin, but not with the complement fixation. The agar gel precipitin test can be used to predict whether a given serum is satisfactory for use in production of a conjugate for direct fluorescent antibody tests. Serums with an...

  9. Quantitative clinical uptake measurements using conjugate counting

    International Nuclear Information System (INIS)

    While the use of conjugate counting for determination of organ uptake in human subjects has been extensively described, in the present study the determination of the organ uptake of ortho-iodohippurate presented several opportunities for validation of the in vivo counting data. Ortho-iodohippurate is distributed in the extracellular space, is largely extracted on each pass through the kidneys, and is not significantly deiodinated in vivo. Thus, the kidney uptake rate should be proportional to the blood level, the appearance rate of activity in the bladder is equal to the disappearance rate from the kidneys, and direct measurement of activity in the urine after voiding provides an internal standard for imaging measurements of bladder activity. Since the activity levels in the kidneys, bladder, and remainder of the body changed fairly rapidly, especially in the first 20 to 30 minutes following injection, posterior images of the trunk including kidneys and bladder were obtained continuously using a gamma camera fitted with a diverging collimator for 30 minutes and then at intervals for several hours. Simultaneous conjugate counting determinations were made using a whole body scanning system previously described at these meetings. Imaging data corrected for decay and adjacent background were fitted by least squares methods to curves representing a sum of exponentials, and the curves were normalized to the conjugate uptake measurements. The uptake curves of the kidneys and bladder matched well with the direct measurements of the urinary excretion. Data were collected in 16 normal subjects, and the estimated absorbed dose was calculated for the kidneys, the bladder and the remainder of the body for seven radioisotopes of iodine. 4 references, 6 figures, 2 tables

  10. A class of globally convergent conjugate gradient methods

    Institute of Scientific and Technical Information of China (English)

    戴彧虹; 袁亚湘

    2003-01-01

    Conjugate gradient methods are very important ones for solving nonlinear optimization problems,especially for large scale problems. However, unlike quasi-Newton methods, conjugate gradient methods wereusually analyzed individually. In this paper, we propose a class of conjugate gradient methods, which can beregarded as some kind of convex combination of the Fletcher-Reeves method and the method proposed byDai et al. To analyze this class of methods, we introduce some unified tools that concern a general methodwith the scalarβk having the form of φk/φk-1. Consequently, the class of conjugate gradient methods canuniformly be analyzed.

  11. 2-Deoxystreptamine Conjugates by Truncation–Derivatization of Neomycin

    Directory of Open Access Journals (Sweden)

    Floris L. van Delft

    2010-03-01

    Full Text Available A small library of truncated neomycin-conjugates is prepared by consecutive removal of 2,6-diaminoglucose rings, oxidation-reductive amination of ribose, oxidation-conjugation of aminopyridine/aminoquinoline and finally dimerization. The dimeric conjugates were evaluated for antibacterial activity with a unique hemocyanin-based biosensor. Based on the outcome of these results, a second-generation set of monomeric conjugates was prepared and found to display significant antibacterial activity, in particular with respect to kanamycin-resistant E. coli.

  12. Sources and Bioactive Properties of Conjugated Dietary Fatty Acids.

    Science.gov (United States)

    Hennessy, Alan A; Ross, Paul R; Fitzgerald, Gerald F; Stanton, Catherine

    2016-04-01

    The group of conjugated fatty acids known as conjugated linoleic acid (CLA) isomers have been extensively studied with regard to their bioactive potential in treating some of the most prominent human health malignancies. However, CLA isomers are not the only group of potentially bioactive conjugated fatty acids currently undergoing study. In this regard, isomers of conjugated α-linolenic acid, conjugated nonadecadienoic acid and conjugated eicosapentaenoic acid, to name but a few, have undergone experimental assessment. These studies have indicated many of these conjugated fatty acid isomers commonly possess anti-carcinogenic, anti-adipogenic, anti-inflammatory and immune modulating properties, a number of which will be discussed in this review. The mechanisms through which these bioactivities are mediated have not yet been fully elucidated. However, existing evidence indicates that these fatty acids may play a role in modulating the expression of several oncogenes, cell cycle regulators, and genes associated with energy metabolism. Despite such bioactive potential, interest in these conjugated fatty acids has remained low relative to the CLA isomers. This may be partly attributed to the relatively recent emergence of these fatty acids as bioactives, but also due to a lack of awareness regarding sources from which they can be produced. In this review, we will also highlight the common sources of these conjugated fatty acids, including plants, algae, microbes and chemosynthesis. PMID:26968402

  13. Rhenium 188 labelling of peptide conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Melendez-Alafort, Laura

    2001-07-01

    Many human tumours express high levels, of somatostatin receptors. In order to make possible a radiotherapeutic treatment of this kind for tumour a series of somatostatin analogues that can tightly chelate beta emitting isotopes have been developed in recent years. The work carried out for this thesis has been aimed towards development of a new therapeutic radiopharmaceutical for treatment of somatostatin receptor positive tumours. The first chapters describe work with technetium-99m to establish the labelling and analytical conditions for a somatostatin analogue, [Tyr{sup 3}]-octreotide (TOC), as a precursor to undertaking labelling studies with the beta emitter rhenium-188. 6-Hydrazinopyridine-3-carboxylic acid (HYNIC) was conjugated to TOC and labelled with {sup 99m} using different coligands. Then the stability, receptor binding and biodistribution of each complex were assessed. {sup 99m}Tc-HYNIC-TOC using EDDA as coligand showed the best characteristics, and was superior for tumour imaging in humans than the commercially available {sup 111}In-DTPA-octreotide. The conditions for labelling the HYNIC-TOC conjugate with {sup 188}Re were then optimised using tricine as a co-ligand. A labelling yield of {approx}80% was achieved. After purification however, the stability of the complex was low. The use of other coligand systems which had proved useful for {sup 99m}Tc labelling was explored, but yields were very poor. Other chelators such as diethylenetriamine pentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA) and mercaptoacetyltriglycine (MAG{sub 3}) were studied as potential co-ligand agents to label the HYNIC-TOC conjugate with {sup 188}Re but, again low yields of the labelled peptide complexes were achieved. A novel {sup 188}Re-HYNIC complex was prepared in high yields using N-N-disubstituted dithiocarbamates as coligands. However to date, the specific activities achieved with this system are relatively low. The use of the [{sup 99m}Tc(CO){sub 3}(H{sub 2}O

  14. Synchronization regimes in conjugate coupled chaotic oscillators.

    Science.gov (United States)

    Karnatak, Rajat; Ramaswamy, Ram; Prasad, Awadhesh

    2009-09-01

    Nonlinear oscillators that are mutually coupled via dissimilar (or conjugate) variables display distinct regimes of synchronous behavior. In identical chaotic oscillators diffusively coupled in this manner, complete synchronization occurs only by chaos suppression when the coupled subsystems drive each other into a regime of periodic dynamics. Furthermore, the coupling does not vanish but acts as an "internal" drive. When the oscillators are mismatched, phase synchronization occurs, while in a master slave configuration, generalized synchrony results. These effects are demonstrated in a system of coupled chaotic Rossler oscillators.

  15. Inorganic Nanoparticles Conjugated with Biofunctional Molecules

    Institute of Scientific and Technical Information of China (English)

    J.H.Choy

    2007-01-01

    1 Results We have attempted to conjugate inorganic nanoparticles with biofunctional molecules.Recently we were quite successful in demonstrating that a two-dimensional inorganic compound like layered double hydroxide (LDH),and natural and synthetic clays can be used as gene or drug delivery carriers1-4.To the best of our knowledge,such inorganic vectors are completely new and different from conventionally developed ones such as viruses and cationic liposomes,those which are limited in certain cases of ap...

  16. Interplay of alternative conjugated pathways and steric interactions on the electronic and optical properties of donor-acceptor conjugated polymers

    KAUST Repository

    Lima, Igo T.

    2014-01-01

    Donor-acceptor π-conjugated copolymers are of interest for a wide range of electronic applications, including field-effect transistors and solar cells. Here, we present a density functional theory (DFT) study of the impact of varying the conjugation pathway on the geometric, electronic, and optical properties of donor-acceptor systems. We consider both linear ("in series"), traditional conjugation among the donor-acceptor moieties versus structures where the acceptor units are appended orthogonally to the linear, donor-only conjugated backbone. Long-range-corrected hybrid functionals are used in the investigation with the values of the tuned long-range separation parameters providing an estimate of the extent of conjugation as a function of the oligomer architecture. Considerable differences in the electronic and optical properties are determined as a function of the nature of the conjugation pathway, features that should be taken into account in the design of donor-acceptor copolymers.

  17. Evaluation of Haemophilus influenzae Type B Conjugate Vaccine (Meningococcal Protein Conjugate in Canadian Infants

    Directory of Open Access Journals (Sweden)

    David W Scheifele

    1994-01-01

    Full Text Available Objective: To assess adverse effects and immune responses with a three-dose series of Haemophilus influenzae type b meningococcal protein conjugate (PedvaxHIB or Hib.OMP vaccine, including any immunological response alterations from concurrent administration with routine vaccines for infants.

  18. Synthesis of gold and silver nanoparticle S-ovalbumin protein conjugates by in situ conjugation process

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Deepti, E-mail: deeptimishrajoshi@gmail.com; Soni, R. K. [Indian Institute of Technology Delhi, Physics Department (India)

    2015-05-15

    Pure gold and silver nanoparticle (NP) generation and their conjugation with protein S-ovalbumin using in situ conjugation process have been reported. The in situ conjugation involves nanosecond pulse laser ablation of pure metal target in the protein S-ovalbumin solution. Transmission electron microscopy (TEM) and UV–Visible absorption results show decrease in mean NP size along with narrow particle size distribution on ablation in S-ovalbumin solution as compared to ablation in water for both Au and Ag NPs. Also, the NP size reduction was found to be dependent on the concentration of S-ovalbumin. For AuNPs, spherical NPs of mean size 4 nm with particle size distribution 2–6 nm were obtained at 300 nM S-ovalbumin concentration. Further, it has been observed that the resultant in situ-conjugated colloid gold and silver NP solutions were quite stable even in the presence of NaCl at physiological salt concentration (0.15 M). On post-laser irradiation (532 nm, 15 mJ) for 20 min, 9 nm red shift in surface plasmon resonance peak (SPR), along with increased broadening towards longer wavelength, was observed in the AuNPs–S-ovalbumin sample. Further increase in the time of irradiation showed shift in AuNPs–S-ovalbumin SPR towards lower wavelength. On laser irradiation (532 nm, 15 mJ) for 20 min, no significant change was observed in the line shape of the plasmon absorption band of the AgNPs–S-ovalbumin conjugate. FTIR spectra revealed that S-ovalbumin peptide backbone and secondary structure remain unchanged on laser irradiation during in situ conjugation process. Thus, integrity of S-ovalbumin does not get affected, and no degradation of S-ovalbumin takes place on laser-induced in situ conjugation. Raman results confirm that both Au and Ag NPs interact with S-ovalbumin via thiol-bearing cysteine residues of the disulfide bond.

  19. Antibody-Conjugated Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Manuel Arruebo

    2009-01-01

    Full Text Available Nanoscience and Nanotechnology have found their way into the fields of Biotechnology and Medicine. Nanoparticles by themselves offer specific physicochemical properties that they do not exhibit in bulk form, where materials show constant physical properties regardless of size. Antibodies are nanosize biological products that are part of the specific immune system. In addition to their own properties as pathogens or toxin neutralizers, as well as in the recruitment of immune elements (complement, improving phagocytosis, cytotoxicity antibody dependent by natural killer cells, etc., they could carry several elements (toxins, drugs, fluorochroms, or even nanoparticles, etc. and be used in several diagnostic procedures, or even in therapy to destroy a specific target. The conjugation of antibodies to nanoparticles can generate a product that combines the properties of both. For example, they can combine the small size of nanoparticles and their special thermal, imaging, drug carrier, or magnetic characteristics with the abilities of antibodies, such as specific and selective recognition. The hybrid product will show versatility and specificity. In this review, we analyse both antibodies and nanoparticles, focusing especially on the recent developments for antibody-conjugated nanoparticles, offering the researcher an overview of the different applications and possibilities of these hybrid carriers.

  20. π-Clamp-mediated cysteine conjugation

    Science.gov (United States)

    Zhang, Chi; Welborn, Matthew; Zhu, Tianyu; Yang, Nicole J.; Santos, Michael S.; van Voorhis, Troy; Pentelute, Bradley L.

    2016-02-01

    Site-selective functionalization of complex molecules is one of the most significant challenges in chemistry. Typically, protecting groups or catalysts must be used to enable the selective modification of one site among many that are similarly reactive, and general strategies that selectively tune the local chemical environment around a target site are rare. Here, we show a four-amino-acid sequence (Phe-Cys-Pro-Phe), which we call the ‘π-clamp’, that tunes the reactivity of its cysteine thiol for site-selective conjugation with perfluoroaromatic reagents. We use the π-clamp to selectively modify one cysteine site in proteins containing multiple endogenous cysteine residues. These examples include antibodies and cysteine-based enzymes that would be difficult to modify selectively using standard cysteine-based methods. Antibodies modified using the π-clamp retained binding affinity to their targets, enabling the synthesis of site-specific antibody-drug conjugates for selective killing of HER2-positive breast cancer cells. The π-clamp is an unexpected approach to mediate site-selective chemistry and provides new avenues to modify biomolecules for research and therapeutics.

  1. The coordination dynamics of mobile conjugate reinforcement.

    Science.gov (United States)

    Kelso, J A Scott; Fuchs, Armin

    2016-02-01

    What we know about infant learning and memory is founded largely on systematic studies by the late Carolyn Rovee-Collier (1942-2014) and her associates of a phenomenon called mobile conjugate reinforcement. Experiments show that when a ribbon is attached from a 3-month-old infant's foot to a mobile suspended overhead the baby quickly realizes it can make the mobile move. The mobile, which offers interesting sights and sounds, responds conjugately to the baby's vigorous kicks which increase in rate by a factor of 3-4. In this paper, using the concepts, methods and tools of coordination dynamics, we present a theoretical model which reproduces the experimental observations of Rovee-Collier and others and predicts a number of additional features that can be experimentally tested. The model is a dynamical system consisting of three equations, one for the baby's leg movements, one for the jiggling motion of the mobile and one for the functional coupling between the two. A key mechanism in the model is positive feedback which is shown to depend sensitively on bifurcation parameters related to the infant's level of attention and inertial properties of the mobile. The implications of our model for the dynamical (and developmental) origins of agency are discussed. PMID:26759265

  2. Preparation and characterization of microspheres of albumin-heparin conjugates

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Feijen, Jan

    1991-01-01

    Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form albumin-hepar

  3. A NONMONOTONE CONJUGATE GRADIENT ALGORITHM FOR UNCONSTRAINED OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    DAI Yuhong

    2002-01-01

    Conjugate gradient methods are very important methods for unconstrained optimization, especially for large scale problems. In this paper, we propose a new conjugate gradient method, in which the technique of nonmonotone line search is used. Under mild assumptions, we prove the global convergence of the method. Some numerical results are also presented.

  4. An updated view of plasmid conjugation and mobilization in Staphylococcus.

    Science.gov (United States)

    Ramsay, Joshua P; Kwong, Stephen M; Murphy, Riley J T; Yui Eto, Karina; Price, Karina J; Nguyen, Quang T; O'Brien, Frances G; Grubb, Warren B; Coombs, Geoffrey W; Firth, Neville

    2016-01-01

    The horizontal gene transfer facilitated by mobile genetic elements impacts almost all areas of bacterial evolution, including the accretion and dissemination of antimicrobial-resistance genes in the human and animal pathogen Staphylococcus aureus. Genome surveys of staphylococcal plasmids have revealed an unexpected paucity of conjugation and mobilization loci, perhaps suggesting that conjugation plays only a minor role in the evolution of this genus. In this letter we present the DNA sequences of historically documented staphylococcal conjugative plasmids and highlight that at least 3 distinct and widely distributed families of conjugative plasmids currently contribute to the dissemination of antimicrobial resistance in Staphylococcus. We also review the recently documented "relaxase-in trans" mechanism of conjugative mobilization facilitated by conjugative plasmids pWBG749 and pSK41, and discuss how this may facilitate the horizontal transmission of around 90% of plasmids that were previously considered non-mobilizable. Finally, we enumerate unique sequenced S. aureus plasmids with a potential mechanism of mobilization and predict that at least 80% of all non-conjugative S. aureus plasmids are mobilizable by at least one mechanism. We suggest that a greater research focus on the molecular biology of conjugation is essential if we are to recognize gene-transfer mechanisms from our increasingly in silico analyses. PMID:27583185

  5. Enhanced Antioxidant Activities of Metal Conjugates of Curcumin Derivatives

    OpenAIRE

    Dutta, Sabari; Murugkar, Anupa; Gandhe, Nitasha; Padhye, Subhash

    2001-01-01

    Antioxidant properties of three Curcumin derivatives in which the 1,3-diketone system is appended with nitrogen and sulfur donors and their copper conjugates are examined for the first time. Metal conjugation seems to offer distinct advantages in radical scavenging activities of curcumin compounds.

  6. Link optimization for DWDM transmission with an optical phase conjugation.

    Science.gov (United States)

    Rosa, Paweł; Rizzelli, Giuseppe; Ania-Castañón, Juan Diego

    2016-07-25

    We characterize in-span signal power asymmetry in random distributed feedback ultralong Raman laser-amplified WDM transmission and numerically optimize fiber span length and operating band to achieve the lowest inter-span signal power asymmetry between transmitted and optically conjugated channels in systems relying upon mid-link optical conjugation to combat fiber nonlinear impairments. PMID:27464097

  7. CONVERGENCE PROPERTIES OF THE DEPENDENT PRP CONJUGATE GRADIENT METHODS

    Institute of Scientific and Technical Information of China (English)

    Shujun LIAN; Changyu WANG; Lixia CAO

    2006-01-01

    In this paper, a new region of βκ with respect to βPRPκ is given. With two Armijo-type line searches, the authors investigate the global convergence properties of the dependent PRP conjugate gradient methods, which extend the global convergence results of PRP conjugate gradient method proved by Grippo and Lucidi (1997) and Dai and Yuan (2002).

  8. Enzyme linked immunoassay with stabilized polymer saccharide enzyme conjugates

    Science.gov (United States)

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1997-11-25

    An improvement in enzyme linked immunoassays is disclosed wherein the enzyme is in the form of a water soluble polymer saccharide conjugate which is stable in hostile environments. The conjugate comprises the enzyme which is linked to the polymer at multiple points through saccharide linker groups. 19 figs.

  9. Method for synthesizing peptides with saccharide linked enzyme polymer conjugates

    Science.gov (United States)

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1997-06-17

    A method is disclosed for synthesizing peptides using water soluble enzyme polymer conjugates. The method comprises catalyzing the peptide synthesis with enzyme which has been covalently bonded to a polymer through at least three linkers which linkers have three or more hydroxyl groups. The enzyme is conjugated at lysines or arginines. 19 figs.

  10. Opto-electronic properties of charged conjugated molecules

    NARCIS (Netherlands)

    Fratiloiu, S.

    2007-01-01

    The aim of this thesis is to provide fundamental insight into the nature and opto-electronic properties of charge carriers on conjugated oligomers and polymers. Electronic structure, optical absorption properties and distribution of charge carriers along the chains of different conjugated materials

  11. Responsive Guest Encapsulation of Dynamic Conjugated Microporous Polymers.

    Science.gov (United States)

    Xu, Lai; Li, Youyong

    2016-06-30

    The host-guest complexes of conjugated microporous polymers encapsulating C60 and dye molecules have been investigated systematically. The orientation of guest molecules inside the cavities, have different terms: inside the open cavities of the polymer, or inside the cavities formed by packing different polymers. The host backbone shows responsive dynamic behavior in order to accommodate the size and shape of incoming guest molecule or guest aggregates. Simulations show that the host-guest binding of conjugated polymers is stronger than that of non-conjugated polymers. This detailed study could provide a clear picture for the host-guest interaction for dynamic conjugated microporous polymers. The mechanism obtained could guide designing new conjugated microporous polymers.

  12. Responsive Guest Encapsulation of Dynamic Conjugated Microporous Polymers.

    Science.gov (United States)

    Xu, Lai; Li, Youyong

    2016-01-01

    The host-guest complexes of conjugated microporous polymers encapsulating C60 and dye molecules have been investigated systematically. The orientation of guest molecules inside the cavities, have different terms: inside the open cavities of the polymer, or inside the cavities formed by packing different polymers. The host backbone shows responsive dynamic behavior in order to accommodate the size and shape of incoming guest molecule or guest aggregates. Simulations show that the host-guest binding of conjugated polymers is stronger than that of non-conjugated polymers. This detailed study could provide a clear picture for the host-guest interaction for dynamic conjugated microporous polymers. The mechanism obtained could guide designing new conjugated microporous polymers. PMID:27356483

  13. Genetic Drift Suppresses Bacterial Conjugation in Spatially Structured Populations

    Science.gov (United States)

    Freese, Peter D.; Korolev, Kirill S.; Jiménez, José I.; Chen, Irene A.

    2014-02-01

    Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid agar, and we develop a quantitative understanding by spatial extension of traditional mass-action models. We found that spatial structure suppresses conjugation in surface-associated growth because strong genetic drift leads to spatial isolation of donor and recipient cells, restricting conjugation to rare boundaries between donor and recipient strains. These results suggest that ecological strategies, such as enforcement of spatial structure and enhancement of genetic drift, could complement molecular strategies in slowing the spread of antibiotic resistance genes.

  14. Human glutathione S-transferase-mediated glutathione conjugation of curcumin and efflux of these conjugates in Caco-2 cells

    NARCIS (Netherlands)

    Usta, M.; Wortelboer, H.M.; Vervoort, J.J.M.; Boersma, M.G.; Rietjens, I.M.C.M.; Bladeren, van P.J.; Cnubben, N.H.P.

    2007-01-01

    Curcumin, an alpha,beta-unsaturated carbonyl compound, reacts with glutathione, leading to the formation of two monoglutathionyl curcumin conjugates. In the present study, the structures of both glutathione conjugates of curcumin were identified by LC-MS and one- and two-dimensional H-1 NMR analysis

  15. Human glutathione S-transferase-mediated glutathione conjugation of curcumin and efflux of these conjugates in caco-2 cells

    NARCIS (Netherlands)

    Usta, M.; Wortelboer, H.M.; Vervoort, J.; Boersma, M.G.; Rietjens, I.M.C.M.; Bladeren, P.J. van; Cnubben, N.H.P.

    2007-01-01

    Curcumin, an α,β-unsaturated carbonyl compound, reacts with glutathione, leading to the formation of two monoglutathionyl curcumin conjugates. In the present study, the structures of both glutathione conjugates of curcumin were identified by LC-MS and one- and two-dimensional 1H NMR analysis, and th

  16. Conjugated polymers with pyrrole as the conjugated bridge: synthesis, characterization, and two-photon absorption properties.

    Science.gov (United States)

    Li, Qianqian; Zhong, Cheng; Huang, Jing; Huang, Zhenli; Pei, Zhiguo; Liu, Jun; Qin, Jingui; Li, Zhen

    2011-07-14

    The synthesis, one- and two-photon absorption (2PA) and emission properties of two novel pyrrole-based conjugated polymers (P1 and P2) are reported. They emitted strong yellow-green and orange fluorescence with fluorescent quantum yields (Φ) of 46 and 33%, respectively. Their maximal 2PA cross sections (δ) measured by the two-photon-induced fluorescence method using femtosecond laser pulses in THF were 2392 and 1938 GM per repeating unit, respectively, indicating that the 2PA chromophores consisting of the triphenylamine with nonplanar structure as the donor and electron-rich pyrrole as the conjugated bridge could be the effective repeating units to enhance the δ values.

  17. Conjugate natural convection between horizontal eccentric cylinders

    Science.gov (United States)

    Nasiri, Davood; Dehghan, Ali Akbar; Hadian, Mohammad Reza

    2016-06-01

    This study involved the numerical investigation of conjugate natural convection between two horizontal eccentric cylinders. Both cylinders were considered to be isothermal with only the inner cylinder having a finite wall thickness. The momentum and energy equations were discretized using finite volume method and solved by employing SIMPLER algorithm. Numerical results were presented for various solid-fluid conductivity ratios (KR) and various values of eccentricities in different thickness of inner cylinder wall and also for different angular positions of inner cylinder. From the results, it was observed that in an eccentric case, and for KR 10 value caused an increase in overline{{K_{eq} }} . It was also concluded that in any angular position of inner cylinder, the value of overline{{K_{eq} }} increased with increase in the eccentricity.

  18. Spiropyran main-chain conjugated polymers.

    Science.gov (United States)

    Sommer, Michael; Komber, Hartmut

    2013-01-11

    The first main-chain conjugated copolymers based on alternating spiropyran (SP) and 9,9-dioctylfluorene (F8) units synthesized via Suzuki polycondensation (SPC) are presented. The reaction conditions of SPC are optimized to obtain materials of type P(para-SP-F8) with appreciably high molecular weights up to M(w) ≈ 100 kg mol(-1). (13)C NMR is used to identify the random orientation of the non-symmetric SP unit in P(p-SP-F8). Ultrasound-induced isomerization of P(p-SP-F8) to the corresponding merocyanine form P(p-MC-F8) yields a deep-red solution. This isomerization reaction is followed by (1)H NMR in solution using sonication, whereby the color increasingly changes to deep red. The possibility to incorporate multiple SP units into main-chain polymers significantly broadens existing SP-based polymeric architectures.

  19. Nonlinear optical response in doped conjugated polymers

    CERN Document Server

    Harigaya, K

    1995-01-01

    Exciton effects on conjugated polymers are investigated in soliton lattice states. We use the Su-Schrieffer-Heeger model with long-range Coulomb interactions. The Hartree-Fock (HF) approximation and the single-excitation configuration- interaction (single-CI) method are used to obtain optical absorption spectra. The third-harmonic generation (THG) at off-resonant frequencies is calculated as functions of the soliton concentration and the chain length of the polymer. The magnitude of the THG at the 10 percent doping increases by the factor about 10^2 from that of the neutral system. This is owing to the accumulation of the oscillator strengths at the lowest exciton with increasing the soliton concentration. The increase by the order two is common for several choices of Coulomb interaction strengths.

  20. Identification of excited states in conjugated polymers

    CERN Document Server

    Hartwell, L J

    2003-01-01

    This thesis reports quasi steady state photoinduced absorption measurements from three conjugated polymers: polypyridine (PPy), polyfluorene (PFO) and the emeraldine base (EB) form of polyaniline. The aim of these experiments was to determine the nature of the photoexcited states existing in these materials in the millisecond time domain, as this has important consequences for the operation of real devices manufactured using these materials. The results from the photoinduced absorption experiments are closely compared with published results from pulse radiolysis experiments. In all cases there is very good correspondence between the two data sets, which has enabled the photoexcited states to be assigned with a high degree of confidence. Quasi steady-state photoinduced absorption involves the measurement of the change in absorption of a material in response to optical excitation with a laser beam. The changes in absorption are small, so a instrument was developed and optimised for each different sample. Lock-i...

  1. Conjugated Linoleic Acid (CLA-An Overview

    Directory of Open Access Journals (Sweden)

    D J Crumb

    2011-09-01

    Full Text Available Summary: Conjugated linoleic acid (CLA is a group of octadecadienoic acids that are naturally present in the highest concentrations in foods originating in ruminant animals, and dairy products such as milk. Especially large numbers of CLA polymers have been detected in beef, lamb and milk fat. Results from many in vitro and animal studies, though conflicting, have suggested that CLA supplementation may have beneficial effect on obesity, weight management, cancer, diabetes and atherosclerosis. This article provides a brief overview on the functionality, safety and toxicity of CLA as described in literature. .   Industrial Relevance: CLA is a functional food and dietary supplement ingredient with potential benefits against a number of metabolic chronic diseases. However, the mechanism of action and its toxicological effects are not very well understood. These factors may play an important role in the effectiveness as CLA as a viable functional dietary bioactive compound.

  2. Monotone operators and "bigger conjugate" functions

    CERN Document Server

    Bauschke, Heinz H; Wang, Xianfu; Yao, Liangjin

    2011-01-01

    We study a question posed by Stephen Simons in his 2008 monograph involving "bigger conjugate" (BC) functions and the partial infimal convolution. As Simons demonstrated in his monograph, these function have been crucial to the understanding and advancement of the state-of-the-art of harder problems in monotone operator theory, especially the sum problem. In this paper, we provide some tools for further analysis of BC--functions which allow us to answer Simons' problem in the negative. We are also able to refute a similar but much harder conjecture which would have generalized a classical result of Br\\'ezis, Crandall and Pazy. Our work also reinforces the importance of understanding unbounded skew linear relations to construct monotone operators with unexpected properties.

  3. Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis

    OpenAIRE

    Topuzogullari, Murat; Cakir Koc, Rabia; Dincer Isoglu, Sevil; Bagirova, Melahat; Akdeste, Zeynep; Elcicek, Serhat; Oztel, Olga N.; Yesilkir Baydar, Serap; Canim Ates, Sezen; Allahverdiyev, Adil M

    2013-01-01

    Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant...

  4. Coexistence of Self-pumped Phase Conjugation and Mutual-pumped Phase Conjugation in Ce∶BaTiO3

    Institute of Scientific and Technical Information of China (English)

    SHE Weilong; Lee Wing-Kee

    2000-01-01

    Self-pumped phase conjugation(SPPC) and mutual-pumped phase conjugation (MPPC) have been found to coexist in Ce∶BaTiO3 by using two coherent beams of 514.5nm wavelength from an argon ion laser. Both phase conjugations are of the stimulated backscattering and four-wave mixing type. For 7/6 incident power ratio and 26 mW total incident power,he shortest phase conjugate mirror formation time is 10s . Phase conjugate reflectivity of one the beams can reach 70%,hich is ~20% higher than the SPPC reflectivity using only one beam. When the total incident power is increased to 40 mW and the incident power ratio remains constant,a maximum phase conjugatate reflectivity of as much as 88% is obtained.

  5. Synthesis and antimicrobial activity of gold nanoparticle conjugates with cefotaxime

    Science.gov (United States)

    Titanova, Elena O.; Burygin, Gennady L.

    2016-04-01

    Gold nanoparticles (GNPs) have attracted significant interest as a novel platform for various applications to nanobiotechnology and biomedicine. The conjugates of GNPs with antibiotics and antibodies were also used for selective photothermal killing of protozoa and bacteria. Also the conjugates of some antibiotics with GNPs decreased the number of bacterial growing cells. In this work was made the procedure optimization for conjugation of cefotaxime (a third-generation cephalosporin antibiotic) with GNPs (15 nm) and we examined the antimicrobial properties of this conjugate to bacteria culture of E. coli K-12. Addition of cefotaxime solution to colloidal gold does not change their color and extinction spectrum. For physiologically active concentration of cefotaxime (3 μg/mL), it was shown that the optimum pH for the conjugation was more than 9.5. A partial aggregation of the GNPs in saline medium was observed at pH 6.5-7.5. The optimum concentration of K2CO3 for conjugation cefotaxime with GNPs-15 was 5 mM. The optimum concentration of cefotaxime was at 0.36 μg/mL. We found the inhibition of the growth of E. coli K12 upon application cefotaxime-GNP conjugates.

  6. Nanostructured conjugated polymers in chemical sensors: synthesis, properties and applications.

    Science.gov (United States)

    Correa, D S; Medeiros, E S; Oliveira, J E; Paterno, L G; Mattoso, Luiz C

    2014-09-01

    Conjugated polymers are organic materials endowed with a π-electron conjugation along the polymer backbone that present appealing electrical and optical properties for technological applications. By using conjugated polymeric materials in the nanoscale, such properties can be further enhanced. In addition, the use of nanostructured materials makes possible miniaturize devices at the micro/nano scale. The applications of conjugated nanostructured polymers include sensors, actuators, flexible displays, discrete electronic devices, and smart fabric, to name a few. In particular, the use of conjugated polymers in chemical and biological sensors is made feasible owning to their sensitivity to the physicochemical conditions of its surrounding environment, such as chemical composition, pH, dielectric constant, humidity or even temperature. Subtle changes in these conditions bring about variations on the electrical (resistivity and capacitance), optical (absorptivity, luminescence, etc.), and mechanical properties of the conjugated polymer, which can be precisely measured by different experimental methods and ultimately associated with a specific analyte and its concentration. The present review article highlights the main features of conjugated polymers that make them suitable for chemical sensors. An especial emphasis is given to nanostructured sensors systems, which present high sensitivity and selectivity, and find application in beverage and food quality control, pharmaceutical industries, medical diagnosis, environmental monitoring, and homeland security, and other applications as discussed throughout this review.

  7. CONJUGATED POLYMERS AND POLYELECTROLYTES IN SOLAR PHOTOCONVERSION, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Schanze, Kirk S [University of Florida

    2014-08-05

    This DOE-supported program investigated the fundamental properties of conjugated polyelectrolytes, with emphasis placed on studies of excited state energy transport, self-assembly into conjugated polyelectroyte (CPE) based films and colloids, and exciton transport and charge injection in CPE films constructed atop wide bandgap semiconductors. In the most recent grant period we have also extended efforts to examine the properties of low-bandgap donor-acceptor conjugated polyelectrolytes that feature strong visible light absorption and the ability to adsorb to metal-oxide interfaces.

  8. Conjugated organometallic materials containing tungsten centers

    Science.gov (United States)

    Jones, Marya

    Our group is interested in the optical and electronic properties of organometallic analogues of conjugated organic compounds. Specifically, in this thesis we will discuss the properties of complexes in which W≡C moieties replace C≡C fragments within the framework of oligo(phenyleneethynylenes) and a C4-polyyne. A family of derivatives of the type Ph(C≡CC6H4 )m(L)4W≡C(C6H 4C≡C)nPh (m = 0, 1; n = 0, 1, 2) have been prepared and characterized by X-ray crystallography, electronic-absorption spectroscopy, and electrochemistry. This substitution has allowed us to directly compare the electronic and optical properties of these organometallic complexes with those of their organic analogues. We found that while these systems exhibit redox and spectroscopic properties similar to those of their organic counterparts they also exhibit new characteristics that are due to the incorporation of the metal center. The design of these compounds has also allowed us to address how the position of the metal within the backbone affects the electronic and optical properties of these compounds. We found that the position of the metal is important in controlling the electronic structure of the material, thus suggesting that the properties of these compounds can be further tuned by changing the position of the metal within the conjugated carbon chain. In addition, we have appended sulfur and isocyanide functionalities to oligo(phenyleneethynylene) analogues. A family of compounds of the type Cl(dppe) 2W(≡CC6H4-4-(C≡CC6H 4)m-4'-R) (m = l, 2; R = N≡C, SCH2CH 2Si(CH3)3) have been prepared and characterized by electronic-absorption spectroscopy and electrochemistry. Differences between the sulfur and isocyanide functionalities are examined, along with the effects of extending conjugation along the arylidyne chain. Evidence that the sulfur-containing arylidyne complexes form self-assembled monolayers on Au and Pt electrodes is presented. In addition, the electron-transfer rates for

  9. BSA-boronic acid conjugate as lectin mimetics.

    Science.gov (United States)

    Narla, Satya Nandana; Pinnamaneni, Poornima; Nie, Huan; Li, Yu; Sun, Xue-Long

    2014-01-10

    We report bovine serum albumin (BSA)-boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA-BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS-PAGE gel. The BSA-BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA-BA conjugates was conducted by immobilizing BSA-BA onto SPR gold chip. Overall, we demonstrated a BSA-BA-based lectin mimetics for glyco-capturing applications. These lectin mimetics are expected to provide an important tool for glycomics and biosensor research and applications.

  10. A Restarted Conjugate Gradient Method for Ill-posed Problems

    Institute of Scientific and Technical Information of China (English)

    Yan-fei Wang

    2003-01-01

    This paper presents a restarted conjugate gradient iterative algorithm for solving ill-posed problems.The damped Morozov's discrepancy principle is used as a stopping rule. Numerical experiments are given to illustrate the efficiency of the method.

  11. New Conjugates of Quinoxaline as Potent Antitubercular and Antibacterial Agents

    Directory of Open Access Journals (Sweden)

    Ramalingam Peraman

    2016-01-01

    Full Text Available Considering quinoxaline as a privileged structure for the design of potent intercalating agents, some new sugar conjugates of quinoxaline were synthesized and characterized by IR, 1HNMR, 13C NMR, and mass spectral data. In vitro testing for antitubercular and antimicrobial activities was performed against Mycobacterium tuberculosis H37Rv and some pathogenic bacteria. Results revealed that conjugate containing ribose moiety demonstrated the most promising activity against Mycobacteria and bacteria with minimum inhibitory concentrations (MIC of 0.65 and 2.07 μM, respectively. Other conjugates from xylose, glucose, and mannose were moderately active whilst disaccharides conjugates were found to be less active. In silico docking analysis of prototype compound revealed that ATP site of DNA gyrase B subunit could be a possible site for inhibitory action of these synthesized compounds.

  12. New Conjugates of Quinoxaline as Potent Antitubercular and Antibacterial Agents.

    Science.gov (United States)

    Peraman, Ramalingam; Kuppusamy, Rajendran; Killi, Sunil Kumar; Reddy, Y Padmanabha

    2016-01-01

    Considering quinoxaline as a privileged structure for the design of potent intercalating agents, some new sugar conjugates of quinoxaline were synthesized and characterized by IR, (1)HNMR, (13)C NMR, and mass spectral data. In vitro testing for antitubercular and antimicrobial activities was performed against Mycobacterium tuberculosis H 37 Rv and some pathogenic bacteria. Results revealed that conjugate containing ribose moiety demonstrated the most promising activity against Mycobacteria and bacteria with minimum inhibitory concentrations (MIC) of 0.65 and 2.07 μM, respectively. Other conjugates from xylose, glucose, and mannose were moderately active whilst disaccharides conjugates were found to be less active. In silico docking analysis of prototype compound revealed that ATP site of DNA gyrase B subunit could be a possible site for inhibitory action of these synthesized compounds.

  13. Betaine conjugated cationic pullulan as effective gene carrier.

    Science.gov (United States)

    Ambattu, Lizebona August; Rekha, M R

    2015-01-01

    Polyethyleneimne (PEI) is a very efficient transfecting agent but is toxic due to high charge density. To generate a vector which is efficient and less cytotoxic, PEI was conjugated with pullulan (PPEI). Further conjugation was done on PPEI with zwitter ionic betaine which possess antifouling property. PEI of molecular weight 1.2, 2, and 10 kDa were used in the study. Buffering capacity of pullulan-PEI-betaine (PPB) conjugates was found to be sufficient enough for the polymers to make endosomal escape. The polymers proved to be less cytotoxic and highly hemocompatible than PEI. Nuclear localization of YOYO tagged DNA was observed with the nanoplexes developed using PPEI and PPBs of PEI 10 kDa. Transfection efficiency was evaluated using p53 expressing gene and the live dead assay demonstrated very high transfection efficiency with PPB conjugates of PEI 10 kDa. PMID:25304750

  14. Polylactide Conjugates of Camptothecin with Different Drug Release Abilities

    Directory of Open Access Journals (Sweden)

    Ewa Oledzka

    2014-11-01

    Full Text Available Camptothecin-polylactide conjugates (CMPT-PLA were synthesized by covalent incorporation of CMPT into PLA of different microstructure, i.e., atactic PLA and atactic-block-isotactically enriched PLA (Pm = 0.79 via urethane bonds. The kinetic release of CPMT from CMPT-PLA conjugates, tested in vitro under different conditions, is possible in both cases and notably, strongly dependent on PLA microstructure. It shows that release properties of drug-PLA conjugates can be tailored by controlled design of the PLA microstructure, and allow in the case of CMPT-PLA conjugates for the development of highly controlled biodegradable CMPT systems—important delivery systems for anti-cancer agents.

  15. Biomedical Applications of DNA-Conjugated Gold Nanoparticles.

    Science.gov (United States)

    Wang, Chun-Chi; Wu, Shou-Mei; Li, Hung-Wen; Chang, Huan-Tsung

    2016-06-16

    Gold nanoparticles (AuNPs) are useful for diagnostic and biomedical applications, mainly because of their ease in preparation and conjugation, biocompatibility, and size-dependent optical properties. However, bare AuNPs do not possess specificity for targets. AuNPs conjugated with DNA aptamers offer specificity for various analytes, such as proteins and small molecules/ions. Although DNA aptamers themselves have therapeutic and target-recognizing properties, they are susceptible to degradation in vivo. When DNA aptamers are conjugated to AuNPs, their stability and cell uptake efficiency both increase, making aptamer-AuNPs suitable for biomedical applications. Additionally, drugs can be efficiently conjugated with DNA aptamer-AuNPs to further enhance their therapeutic efficiency. This review focuses on the applications of DNA aptamer-based AuNPs in several biomedical areas, including anticoagulation, anticancer, antibacterial, and antiviral applications.

  16. Phase conjugation of gap solitons: A numerical study

    Indian Academy of Sciences (India)

    V S C Manga Rao; S Dutta Gupta

    2003-09-01

    We study the effect of a nearby phase-conjugate mirror (PCM) on the gap soliton of a Kerr non-linear periodic structure. We show that phase conjugation of the gap soliton (in the sense of replication of the amplitude profile in the reverse direction) is possible under the condition of PCM reflectivity approaching unity. This is in contrast with the results for linear structures, where the wave profiles can be conjugated for arbitrary values of the PCM reflectivity. The sensitivity of the conjugation of the gap solitons to PCM reflectivity is ascribed to the fine balance of non-linearity with dispersion, necessary for their existence.

  17. Conjugate heat transfer with the entropic lattice Boltzmann method.

    Science.gov (United States)

    Pareschi, G; Frapolli, N; Chikatamarla, S S; Karlin, I V

    2016-07-01

    A conjugate heat-transfer model is presented based on the two-population entropic lattice Boltzmann method. The present approach relies on the extension of Grad's boundary conditions to the two-population model for thermal flows, as well as on the appropriate exact conjugate heat-transfer condition imposed at the fluid-solid interface. The simplicity and efficiency of the lattice Boltzmann method (LBM), and in particular of the entropic multirelaxation LBM, are retained in the present approach, thus enabling simulations of turbulent high Reynolds number flows and complex wall boundaries. The model is validated by means of two-dimensional parametric studies of various setups, including pure solid conduction, conjugate heat transfer with a backward-facing step flow, and conjugate heat transfer with the flow past a circular heated cylinder. Further validations are performed in three dimensions for the case of a turbulent flow around a heated mounted cube.

  18. Conjugated Polymers/DNA Hybrid Materials for Protein Inactivation.

    Science.gov (United States)

    Zhao, Likun; Zhang, Jiangyan; Xu, Huiming; Geng, Hao; Cheng, Yongqiang

    2016-09-01

    Chromophore-assisted light inactivation (CALI) is a powerful tool for analyzing protein functions due to the high degree of spatial and temporal resolution. In this work, we demonstrate a CALI approach based on conjugated polymers (CPs)/DNA hybrid material for protein inactivation. The target protein is conjugated with single-stranded DNA in advance. Single-stranded DNA can form CPs/DNA hybrid material with cationic CPs via electrostatic and hydrophobic interactions. Through the formation of CPs/DNA hybrid material, the target protein that is conjugated with DNA is brought into close proximity to CPs. Under irradiation, CPs harvest light and generate reactive oxygen species (ROS), resulting in the inactivation of the adjacent target protein. This approach can efficiently inactivate any target protein which is conjugated with DNA and has good specificity and universality, providing a new strategy for studies of protein function and adjustment of protein activity.

  19. Preparation of Conjugated Linoleic Acid and Identification of Its Isomers

    Institute of Scientific and Technical Information of China (English)

    郭诤; 张根旺; 孙彦

    2003-01-01

    Conjugated linoleic acid(CLA)is a kind of fatty acid with physiological activities and potential appli-cation prospect ,A synthesis method of conjugated linoleic acid and a purification technology were studied .CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material,The purity of CLA and total recovery of the product was more than 95% and 48%,respectively,The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC)linked to mass spectrometry(MS) and Fourier transform infrared spectroscopy(FTIR),The total amount of the two main isomers (9cis,11trans-and 10trans,12cis-CLA) determined by GC was more than 90% of the product.

  20. Fluorescence array-based sensing of nitroaromatics using conjugated polyelectrolytes.

    Science.gov (United States)

    Wu, Jiatao; Tan, Chunyan; Chen, Zhifang; Chen, Yu Zong; Tan, Ying; Jiang, Yuyang

    2016-05-23

    A sensor array consisting of six cationic fluorescent conjugated polyelectrolytes (CPEs) is reported, which could readily differentiate between nine closely related hydrophilic nitroaromatics (NACs) in separate aqueous solutions by fluorescence pattern recognition and linear discrimination analysis (LDA). PMID:27169808

  1. Gauge Transformations For Self/Anti-Self Charge Conjugate States

    CERN Document Server

    Dvoeglazov, V V

    1998-01-01

    Gauge transformations of type-II spinors are considered in the Majorana-Ahluwalia construct for self/anti-self charge conjugate states. Some speculations on the relations of this model with the earlier ones are given.

  2. Partial Hermitian Conjugate Separability Criteria for Pure Quantum States

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xin; WU Hua; LI Yan-Song; LONG Gui-Lu

    2009-01-01

    We propose a criterion for the separability of quantum pure states using the concept of a partial Hermitian conjugate.It is equivalent to the usual positive partial transposition criteria,with a simple physical interpretation.

  3. "Angle" Operator Conjugate to Photon's Intrinsic Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    范洪义

    2001-01-01

    We find the correct "angle" operator conjugate to the intrinsic angular momentum of the photon by introducing a suitable representation which involves both left-handed and right-handed polarization photon operators.

  4. DNA Interaction Studies of Selected Polyamine Conjugates

    Science.gov (United States)

    Szumilak, Marta; Merecz, Anna; Strek, Malgorzata; Stanczak, Andrzej; Inglot, Tadeusz W.; Karwowski, Boleslaw T.

    2016-01-01

    The interaction of polyamine conjugates with DNA double helix has been studied. Binding properties were examined by ethidium bromide (EtBr) displacement and DNA unwinding/topoisomerase I/II (Topo I/II) activity assays, as well as dsDNA thermal stability studies and circular dichroism spectroscopy. Genotoxicity of the compounds was estimated by a comet assay. It has been shown that only compound 2a can interact with dsDNA via an intercalative binding mode as it displaced EtBr from the dsDNA-dye complex, with Kapp = 4.26 × 106 M−1; caused an increase in melting temperature; changed the circular dichroism spectrum of dsDNA; converted relaxed plasmid DNA into a supercoiled molecule in the presence of Topo I and reduced the amount of short oligonucleotide fragments in the comet tail. Furthermore, preliminary theoretical study has shown that interaction of the discussed compounds with dsDNA depends on molecule linker length and charge distribution over terminal aromatic chromophores. PMID:27657041

  5. Theory of Periodic Conjugate Heat Transfer

    CERN Document Server

    Zudin, Yuri B

    2012-01-01

    This book presents the theory of periodic conjugate heat transfer in a detailed way. The effects of thermophysical properties and geometry of a solid body on the commonly used and experimentally determined heat transfer coefficient are analytically presented from a general point of view. The main objective of the book is a simplified description of the interaction between a solid body and a fluid as a boundary value problem of the heat conduction equation for the solid body. At the body surface, the true heat transfer coefficient is composed of two parts: the true mean value resulting from the solution of the steady state heat transfer problem and a periodically variable part, the periodic time and length to describe the oscillatory hydrodynamic effects. The second edition is extended by (i) the analysis of stability boundaries in helium flow at supercritical conditions in a heated channel with respect to the interaction between a solid body and a fluid; (ii) a periodic model and a method of heat transfer sim...

  6. Stellar photometry with Multi Conjugate Adaptive Optics

    CERN Document Server

    Fiorentino, Giuliana; McConnachie, Alan; Stetson, Peter B; Bono, Giuseppe; Turri, Paolo; Andersen, David; Veran, Jean-Pierre; Diolaiti, Emiliano; Schreiber, Laura; Ciliegi, Paolo; Bellazzini, Michele; Tolstoy, Eline; Monelli, Matteo; Iannicola, Giacinto; Ferraro, Ivan; Testa, Vincenzo

    2016-01-01

    We overview the current status of photometric analyses of images collected with Multi Conjugate Adaptive Optics (MCAO) at 8-10m class telescopes that operated, or are operating, on sky. Particular attention will be payed to resolved stellar population studies. Stars in crowded stellar systems, such as globular clusters or in nearby galaxies, are ideal test particles to test AO performance. We will focus the discussion on photometric precision and accuracy reached nowadays. We briefly describe our project on stellar photometry and astrometry of Galactic globular clusters using images taken with GeMS at the Gemini South telescope. We also present the photometry performed with DAOPHOT suite of programs into the crowded regions of these globulars reaching very faint limiting magnitudes Ks ~21.5 mag on moderately large fields of view (~1.5 arcmin squared). We highlight the need for new algorithms to improve the modeling of the complex variation of the Point Spread Function across the ?eld of view. Finally, we outl...

  7. Microfluidic Fabrication of Conjugated Polymer Sensor Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Imsung; Song, Simon [Hanyang University, Seoul (Korea, Republic of)

    2014-10-15

    We propose a fabrication method for polydiacetylene (PDA)-embedded hydrogel microfibers on a microfluidic chip. These fibers can be applied to the detection of cyclodextrines (CDs), which are a family of sugar and aluminum ions. PDA, a family of conjugated polymers, has unique characteristics when used for a sensor, because it undergoes a blue-to-red color transition and nonfluorescence-to-fluorescence transition in response to environmental stimulation. PDAs have different sensing characteristics depending on the head group of PCDA. By taking advantage of ionic crosslinking-induced hydrogel formation and the 3D hydrodynamic focusing effect on a microfluidic chip, PCDA-EDEA-derived diacetylene (DA) monomer-embedded microfibers were successfully fabricated. UV irradiation of the fibers afforded blue-colored PDA, and the resulting blue PDA fibers underwent a phase transition to red and emitted red fluorescence upon exposure to CDs and aluminum ions. Their fluorescence intensity varied depending on the CDs and aluminum ion concentrations. This phase transition was also observed when the fibers were dried.

  8. Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins

    DEFF Research Database (Denmark)

    Houen, G.; Olsen, D.T.; Hansen, P.R.;

    2003-01-01

    protein was conjugated with glutathione, the conjugation ratio determined by acid hydrolysis, and amino acid analysis performed with quantification of carboxymethyl cysteine. Elution of conjugates from the resin by a salt gradient revealed considerable heterogeneity in the degree of derivatization......, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates...

  9. Optimization of PAMAM-gold nanoparticle conjugation for gene therapy

    OpenAIRE

    Figueroa, Elizabeth R.; Lin, Adam Y.; Yan, Jiaxi; Luo, Laureen; Foster, Aaron E.; Drezek, Rebekah A.

    2013-01-01

    The development of efficient and biocompatible non-viral vectors for gene therapy remains a great challenge, and exploiting the properties of both nanoparticle carriers and cationic polymers is an attractive approach. In this work, we have developed gold nanoparticle (AuNP) polyamidoamine (PAMAM) conjugates for use as non-viral transfection agents. AuPAMAM conjugates were prepared by crosslinking PAMAM dendrimers to carboxylic-terminated AuNPs via EDC and sulfo-NHS chemistry. EDC and sulfo-NH...

  10. Fluorescent non-conjugated polymer dots for targeted cell imaging

    Science.gov (United States)

    Sun, Bin; Zhao, Bin; Wang, Dandan; Wang, Yibo; Tang, Qi; Zhu, Shoujun; Yang, Bai; Sun, Hongchen

    2016-05-01

    Through the chemical crosslinking of the sub-fluorophore, linear non-conjugated polymers can possess strong photoluminescence (PL), which is a very important fluorescence behavior and the non-conjugated polymer dots (PDs) are efficient bio-fluorophores for bio-based applications. Herein, the new type of non-conjugated polyethyleneimine (PEI) PDs was further modified by targeting molecules (folic acid) for a new generation of bio-fluorophores. The free folic acid can quench the PL of PDs by energy transfer, while the conjugated folic acid@PDs (FA@PDs) can still maintain their PL properties to a certain degree. The FA@PDs also possess lower toxicity compared with free PDs, which is possibly due to blocking of the amino groups. Moreover, we investigated the targeted bioimaging applications of the FA@PDs, which gave a very important direction for application of these types of materials.Through the chemical crosslinking of the sub-fluorophore, linear non-conjugated polymers can possess strong photoluminescence (PL), which is a very important fluorescence behavior and the non-conjugated polymer dots (PDs) are efficient bio-fluorophores for bio-based applications. Herein, the new type of non-conjugated polyethyleneimine (PEI) PDs was further modified by targeting molecules (folic acid) for a new generation of bio-fluorophores. The free folic acid can quench the PL of PDs by energy transfer, while the conjugated folic acid@PDs (FA@PDs) can still maintain their PL properties to a certain degree. The FA@PDs also possess lower toxicity compared with free PDs, which is possibly due to blocking of the amino groups. Moreover, we investigated the targeted bioimaging applications of the FA@PDs, which gave a very important direction for application of these types of materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01909a

  11. Impacts of the 13-valent pneumococcal conjugate vaccine in children

    OpenAIRE

    Susanna Esposito; Nicola Principi

    2015-01-01

    Applications of the heptavalent pneumococcal conjugate vaccine (PCV7) in the pediatric immunization schedule have dramatically reduced the incidence of pneumococcal diseases in both vaccinated children and unvaccinated individuals of all ages. However, increased infections caused by non-PCV7 serotypes have been reported by several groups. To overcome this problem, new vaccines covering more serotypes including the emerging serotypes have been developed. The 13-valent pneumococcal conjugate va...

  12. Pneumococcal Conjugate Vaccine for Adults: A New Paradigm

    OpenAIRE

    Paradiso, Peter R

    2012-01-01

    A 13-valent pneumococcal conjugate vaccine has been studied in adults aged ≥50 years to compare the immune response to that induced by the 23-valent pneumococcal polysaccharide vaccine, which has been the standard of care over the past 30 years. The results demonstrate that adults, regardless of whether they are naive or previously vaccinated with the polysaccharide vaccine, have an overall superior antibody response when vaccinated with the conjugate vaccine compared with the pneumococcal po...

  13. Pneumococcal conjugate vaccine in adults: Let's see what happens.

    Science.gov (United States)

    Paradiso, Peter R

    2016-07-01

    The recent recommendation for the use of the 13-valent pneumococcal conjugate vaccine (PCV13) in adults 65 y of age and older, provides a new tool for preventing disease in this at-risk population. The conjugate vaccine induces a T-cell dependent response, which distinguishes it from the polysaccharide vaccine and could provide the longer-term protection necessary to have a significant impact in this population. PMID:26901618

  14. Pneumococcal vaccination of older adults: Conjugate or polysaccharide?

    OpenAIRE

    Fedson, David S; Guppy, Martin J.

    2013-01-01

    Invasive pneumococcal disease continues to be important problem for older adults. Pneumococcal polysaccharide vaccine (PPV23) has a clinical effectiveness of 43–81%, and following primary vaccination and revaccination, antibody responses last 5–10 y. Hyporesponsiveness to a second dose of vaccine has not been shown to be a significant problem. The use of pneumococcal conjugate vaccines (initially PCV7; more recently PCV13) has led to a dramatic fall in the incidence of conjugate vaccine-type ...

  15. Conjugate boundary condition, hidden matters, and gauge-Higgs inflation

    CERN Document Server

    Abe, Yugo; Kawamura, Yoshiharu; Nishikawa, Yasunari

    2016-01-01

    We propose an idea that hidden matters can be separated according to gauge quantum numbers from the visible ones by the difference of boundary conditions on extra dimensions. We formulate 5-dimensional gauge theories yielding conjugate boundary conditions besides ordinary ones on $S^1/Z_2$, and examine physical implications concerning hidden matters on an extension of the standard model coexisting different types of boundary conditions. A model with conjugate boundary conditions is applied on a gauge-Higgs inflation scenario.

  16. A NOTE ON THE NONLINEAR CONJUGATE GRADIENT METHOD

    Institute of Scientific and Technical Information of China (English)

    Yu-hong Dai; Ya-xiang Yuan

    2002-01-01

    The conjugate gradient method for unconstrained optimization problems varies with a scalar. In this note, a general condition concerning the scalar is given, which ensures the global convergence of the method in the case of strong Wolfe line searches. It is also discussed how to use the result to obtain the convergence of the famous Fletcher-Reeves, and Polak-Ribiere-Polyak conjugate gradient methods. That the condition cannot be relaxed in some sense is mentioned.

  17. Cross-conjugation and quantum interference: a general correlation?

    DEFF Research Database (Denmark)

    Valkenier, Hennie; Guedon, Constant M.; Markussen, Troels;

    2014-01-01

    We discuss the relationship between the pi-conjugation pattern, molecular length, and charge transport properties of molecular wires, both from an experimental and a theoretical viewpoint. Specifically, we focus on the role of quantum interference in the conductance properties of cross-conjugated...... interference occurs can be tuned by the choice of side group. The latter provides an outlook for future devices in this fascinating field connecting chemistry and physics....

  18. Solid State NMR and Fluorescence Studies of Conjugated Polymer Nanocomposties

    Institute of Scientific and Technical Information of China (English)

    Chao Jun JING; Liu Sheng CHEN; Yi SHI; Xi Gao JIN

    2005-01-01

    13C spin-lattice relaxation times (T1) of a conjugated polymer MEH-PPV in polymer/layered silicate nanocomposites together with the steady state fluorescence emission and transient fluorescence decay measurements have been investigated. The T1 values of the conjugated carbons decrease dramatically according to the reduction of polymer concentration in the nano composites, while the fluorescence life times (τ) show a linear prolonging tendency. The results are explained from the point of view of molecular dynamics.

  19. Synthesis of Conjugated Polymers for Light Emitting and Photovoltalc Applications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results The initial report of polymeric light-emitting diodes (PLEDs) based on poly(p-phenylenevinylene) gave birth to an intense research effort in conjugated polymers, primarily focused on the development of optoelectronic and electrochemical devices. Significant developments in modern synthetic chemistry, especially the chemistry of carbon-carbon bond formation have allowed the synthesis of various well-defined conjugated polymers and oligomers with optimized physical properties.Meanwhile, these re...

  20. Biological Sensing and DNA Templated Electronics Using Conjugated Polymers

    OpenAIRE

    Björk, Per

    2007-01-01

    Conjugated polymers have been found useful in a wide range of applications such as solar cells, sensor elements and printed electronics, due to their optical and electronic properties. Functionalization with charged side chains has enabled water solubility, resulting in an enhanced interaction with biomolecules. This thesis focus on the emerging research fields, where these conjugated polyelectrolytes (CPEs) are combined with biomolecules for biological sensing and DNA nanowire assembling. CP...

  1. Protein carriers of conjugate vaccines: characteristics, development, and clinical trials.

    Science.gov (United States)

    Pichichero, Michael E

    2013-12-01

    The immunogenicity of polysaccharides as human vaccines was enhanced by coupling to protein carriers. Conjugation transformed the T cell-independent polysaccharide vaccines of the past to T cell-dependent antigenic vaccines that were much more immunogenic and launched a renaissance in vaccinology. This review discusses the conjugate vaccines for prevention of infections caused by Hemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis. Specifically, the characteristics of the proteins used in the construction of the vaccines including CRM, tetanus toxoid, diphtheria toxoid, Neisseria meningitidis outer membrane complex, and Hemophilus influenzae protein D are discussed. The studies that established differences among and key features of conjugate vaccines including immunologic memory induction, reduction of nasopharyngeal colonization and herd immunity, and antibody avidity and avidity maturation are presented. Studies of dose, schedule, response to boosters, of single protein carriers with single and multiple polysaccharides, of multiple protein carriers with multiple polysaccharides and conjugate vaccines administered concurrently with other vaccines are discussed along with undesirable consequences of conjugate vaccines. The clear benefits of conjugate vaccines in improving the protective responses of the immature immune systems of young infants and the senescent immune systems of the elderly have been made clear and opened the way to development of additional vaccines using this technology for future vaccine products. PMID:23955057

  2. Selective esterification of non-conjugated carboxylic acids in the presence of conjugated or aromatic carboxylic acids over active carbon supported methanesulfonic acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Non-conjugated carboxylic acids are selectively esterified in good yields in the presence of conjugated or aromatic carboxylic acids by stirring over active carbon supported methanesulfonic acid in di-chloromethane at room temperature.

  3. Antibody conjugate radioimmunotherapy of superficial bladder cancer

    Directory of Open Access Journals (Sweden)

    Alan Perkins

    2002-09-01

    Full Text Available The administration of antibody conjugates for cancer therapy is now proving to be of clinical value. We are currently undertaking a programme of clinical studies using the monoclonal antibody C595 (IgG3 which reacts with the MUC1 glycoprotein antigen that is aberrantly expressed in a high proportion of bladder tumours. Radioimmunoconjugates of the C595 antibody have been produced with high radiolabelling efficiency and immunoreactivity using Tc-99m and In-111 for diagnostic imaging, and disease staging and the cytotoxic radionuclides Cu-67 and Re-188 for therapy of superficial bladder cancer. A Phase I/II therapeutic trail involving the intravesical administration of antibody directly into the bladder has now begun.A administração de anticorpos conjugados para o tratamento do câncer está agora provando ser de valor clínico. Nós estamos atualmente realizando um programa de estudos clínicos usando o anticorpo monoclonal C595 (IgG3 que reage com a glicoproteína MUC1 que está aberrantemente expressa numa alta proporção de tumores de bexiga. Tem sido produzidos radioimunoconjugados do anticorpo C595, com alta eficiência de radiomarcação e a imunoreatividade, usando-se o Tc-99m e In-111, para o diagnóstico por imagem e estagiamento de doenças. Tem sido produzidos, também, radionuclídeos citotóxicos (Cu-67 e Re-188 para o tratamento de cânceres superficiais de bexiga. A fase terapêutica I/II já se iniciou, envolvendo a administração intravesical do anticorpo diretamente na bexiga.

  4. Dosing Schedules for Pneumococcal Conjugate Vaccine

    Science.gov (United States)

    2014-01-01

    Since second generation pneumococcal conjugate vaccines (PCVs) targeting 10 and 13 serotypes became available in 2010, the number of national policy makers considering these vaccines has steadily increased. An important consideration for a national immunization program is the timing and number of doses—the schedule—that will best prevent disease in the population. Data on disease epidemiology and the efficacy or effectiveness of PCV schedules are typically considered when choosing a schedule. Practical concerns, such as the existing vaccine schedule, and vaccine program performance are also important. In low-income countries, pneumococcal disease and deaths typically peak well before the end of the first year of life, making a schedule that provides PCV doses early in life (eg, a 6-, 10- and 14-week schedule) potentially the best option. In other settings, a schedule including a booster dose may address disease that peaks in the second year of life or may be seen to enhance a schedule already in place. A large and growing body of evidence from immunogenicity studies, as well as clinical trials and observational studies of carriage, pneumonia and invasive disease, has been systematically reviewed; these data indicate that schedules of 3 or 4 doses all work well, and that the differences between these regimens are subtle, especially in a mature program in which coverage is high and indirect (herd) effects help enhance protection provided directly by a vaccine schedule. The recent World Health Organization policy statement on PCVs endorsed a schedule of 3 primary doses without a booster or, as a new alternative, 2 primary doses with a booster dose. While 1 schedule may be preferred in a particular setting based on local epidemiology or practical considerations, achieving high coverage with 3 doses is likely more important than the specific timing of doses. PMID:24336059

  5. Optical observations geomagnetically conjugate to sprite-producing lightning discharges

    Directory of Open Access Journals (Sweden)

    R. A. Marshall

    2005-09-01

    Full Text Available Theoretical studies have predicted that large positive cloud-to-ground discharges can trigger a runaway avalanche process of relativistic electrons, forming a geomagnetically trapped electron beam. The beam may undergo pitch angle and energy scattering during its traverse of the Earth's magnetosphere, with a small percentage of electrons remaining in the loss cone and precipitating in the magnetically conjugate atmosphere. In particular, N2 1P and N2+1N optical emissions are expected to be observable. In July and August 2003, an attempt was made to detect these optical emissions, called "conjugate sprites", in correlation with sprite observations in Europe near . Sprite observations were made from the Observatoire du Pic du Midi (OMP in the French Pyrenées, and VLF receivers were installed in Europe to detect causative sferics and ionospheric disturbances associated with sprites. In the Southern Hemisphere conjugate region, the Wide-angle Array for Sprite Photometry (WASP was deployed at the South African Astronomical Observatory (SAAO, near Sutherland, South Africa, to observe optical emissions with a field-of-view magnetically conjugate to the Northern Hemisphere observing region. Observations at OMP revealed over 130 documented sprites, with WASP observations covering the conjugate region successfully for 30 of these events. However, no incidences of optical emissions in the conjugate hemisphere were found. Analysis of the conjugate optical data from SAAO, along with ELF energy measurements from Palmer Station, Antarctica, and charge-moment analysis, show that the lightning events during the course of this experiment likely had insufficient intensity to create a relativistic beam.

    Keywords. Ionosphere (Ionsophere-magnetosphere interactions; Ionospheric disturbances; Instruments and techniques

  6. Recent Advances in Conjugated Polymers for Light Emitting Devices

    Directory of Open Access Journals (Sweden)

    Mohan Raja

    2011-03-01

    Full Text Available A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.

  7. Recent advances in conjugated polymers for light emitting devices.

    Science.gov (United States)

    Alsalhi, Mohamad Saleh; Alam, Javed; Dass, Lawrence Arockiasamy; Raja, Mohan

    2011-01-01

    A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review.

  8. Recent advances in conjugated polymers for light emitting devices.

    Science.gov (United States)

    Alsalhi, Mohamad Saleh; Alam, Javed; Dass, Lawrence Arockiasamy; Raja, Mohan

    2011-01-01

    A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review. PMID:21673938

  9. Optical study of pi-conjugated polymers and pi-conjugated polymers/fullerene blends

    Science.gov (United States)

    Drori, Tomer

    In this research, we studied the optical properties of a variety of pi-conjugated polymers and pi-conjugated polymers/fullerene blends, using various continuous wave optical spectroscopies. We found an illumination-induced metastable polaron-supporting phase in films of a soluble derivative of poly-p-phenylene vinylene (MEH-PPV). Pristine, MEH-PPV polymer films in the dark do not show long-lived photogenerated polarons. Prolonged UV illumination, however, is found to induce a reversible, metastable phase characterized by its ability to support abundant long-lived photogenerated polarons. We also discovered a photobleaching band in our photomodulation measurement around 0.9eV that scales with and thus is related to the observed polaron band. In the dark, the illumination-induced metastable phase reverts back to the phase of the original MEH-PPV within about 30 min at room temperature. We also applied our experimental techniques in polymer/fullerene blends for studying the photophysics of bulk heterostructures with below-gap excitation. In contrast to the traditional view, we found that below-gap excitation, which is incapable of generating intrachain excitons, nevertheless efficiently generates polarons on the polymer chains and fullerene molecules. Using frequency dependence photomodulation, we distinguished between the two mechanisms of photoinduced charge transfer using above-gap and below-gap excitations, and found a distinguishable long polaron lifetime when photogenerated with below-gap excitation. The polaron action spectrum extends deep inside the gap as a result of a charge-transfer complex state formed between the polymer chain and fullerene molecule. Using the electroabsorption technique, we were able to detect the optical transition of the charge transfer complex state that lies below the gap of the polymer and the fullerene. With appropriate design engineering the long-lived polarons might be harvested in solar cell devices. Another system studied was

  10. New heparin–indomethacin conjugate with an ester linkage: Synthesis, self aggregation and drug delivery behavior

    Energy Technology Data Exchange (ETDEWEB)

    Li, Nan-Nan; Zheng, Bing-Na [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Lin, Jian-Tao [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Guangdong Medical College, Dongguan 523808 (China); Zhang, Li-Ming, E-mail: ceszhlm@mail.sysu.edu.cn [DSAPM Lab and PCFM Lab, Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2014-01-01

    New heparin–indomethacin conjugate with an ester linkage was prepared by the carbodiimide-mediated condensation reaction, and then characterized by FTIR and {sup 1}HNMR analyses. Due to its amphiphilic character, such a conjugate could self-aggregate into spherical nanoparticles in aqueous system, as confirmed by fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. By the in vitro drug release tests, the resultant conjugate nanoparticles were found to have a sustained and esterase-sensitive release behavior for conjugated indomethacin. In addition, the uptake of these conjugate nanoparticles into human nasopharyngeal carcinoma CNE1 cells was confirmed by fluorescence microscopy. - Highlights: • New heparin–indomethacin conjugate with an ester linkage was prepared. • Such a conjugate could self-aggregate into spherical nanoparticles in aqueous system. • The resultant conjugate nanoparticles exhibited an esterase-sensitive drug release behavior. • The resultant conjugate nanoparticles showed the cellular uptake ability in CNE1 cells.

  11. A novel chemistry for conjugating pneumococcal polysaccharides to Luminex microspheres.

    Science.gov (United States)

    Schlottmann, Sonela A; Jain, Neil; Chirmule, Narendra; Esser, Mark T

    2006-02-20

    Here we describe a novel method to conjugate pneumococcal polysaccharides (PnPS) to Luminex microspheres for use in serological assays. 4-(4,6-dimethoxy[1,3,5]triazin-2-yl)-4-methyl-morpholinium (DMTMM) modification of PnPS and conjugation to carboxyl functional groups on Luminex microspheres (COOH-DMTMM method) was shown to be a reproducible chemistry that efficiently conjugated PnPS to Luminex microspheres without affecting the antigenicity of a broad set of PnPS. The COOH-DMTMM method was compared to three other methods for robustness, reproducibility and effect on PnPS antigenicity in a multiplexed assay format. The other methods examined included adsorption of the unmodified PnPS to Luminex microspheres, oxidation of the PnPS to conjugate them to amino-modified microspheres using carbodiimide chemistry and poly-l-lysine modification of the PnPS before conjugating to carboxy Luminex microspheres using carbodiimide chemistry. Of the four methods, the COOH-DMTMM chemistry was shown to be a robust methodology, producing stable PnPS coupled microspheres with a 4-log dynamic range and low cross-reactivity when used in a PnPS-specific IgG serology assay. This novel chemistry should be useful for developing serological assays to measure antibodies to polysaccharides for use in vaccine and epidemiology studies. PMID:16448665

  12. Social behavior and decision making in bacterial conjugation.

    Science.gov (United States)

    Koraimann, Günther; Wagner, Maria A

    2014-01-01

    Bacteria frequently acquire novel genes by horizontal gene transfer (HGT). HGT through the process of bacterial conjugation is highly efficient and depends on the presence of conjugative plasmids (CPs) or integrated conjugative elements (ICEs) that provide the necessary genes for DNA transmission. This review focuses on recent advancements in our understanding of ssDNA transfer systems and regulatory networks ensuring timely and spatially controlled DNA transfer (tra) gene expression. As will become obvious by comparing different systems, by default, tra genes are shut off in cells in which conjugative elements are present. Only when conditions are optimal, donor cells-through epigenetic alleviation of negatively acting roadblocks and direct stimulation of DNA transfer genes-become transfer competent. These transfer competent cells have developmentally transformed into specialized cells capable of secreting ssDNA via a T4S (type IV secretion) complex directly into recipient cells. Intriguingly, even under optimal conditions, only a fraction of the population undergoes this transition, a finding that indicates specialization and cooperative, social behavior. Thereby, at the population level, the metabolic burden and other negative consequences of tra gene expression are greatly reduced without compromising the ability to horizontally transfer genes to novel bacterial hosts. This undoubtedly intelligent strategy may explain why conjugative elements-CPs and ICEs-have been successfully kept in and evolved with bacteria to constitute a major driving force of bacterial evolution.

  13. Controlling molecular ordering in solution-state conjugated polymers.

    Science.gov (United States)

    Zhu, J; Han, Y; Kumar, R; He, Y; Hong, K; Bonnesen, P V; Sumpter, B G; Smith, S C; Smith, G S; Ivanov, I N; Do, C

    2015-10-01

    Rationally encoding molecular interactions that can control the assembly structure and functional expression in a solution of conjugated polymers hold great potential for enabling optimal organic optoelectronic and sensory materials. In this work, we show that thermally-controlled and surfactant-guided assembly of water-soluble conjugated polymers in aqueous solution is a simple and effective strategy to generate optoelectronic materials with the desired molecular ordering. We have studied a conjugated polymer consisting of a hydrophobic thiophene backbone and hydrophilic, thermo-responsive ethylene oxide side groups, which shows a step-wise, multi-dimensional assembly in water. By incorporating the polymer into phase-segregated domains of an amphiphilic surfactant in solution, we demonstrate that both chain conformation and degree of molecular ordering of the conjugated polymer can be tuned in hexagonal, micellar and lamellar phases of the surfactant solution. The controlled molecular ordering in conjugated polymer assembly is demonstrated as a key factor determining the electronic interaction and optical function.

  14. The Preparation and Characterization of Conjugated Linolenic Acid

    Institute of Scientific and Technical Information of China (English)

    Cao Ying; Yang Lin; Chen Zhen-Yu

    2004-01-01

    Conjugated Linolenic Acid (CLN) has recently been shown to have a more strong cytotoxic effect on various human tumor cell lines than CLA. In CLN, all the three double bonds are conjugated, whereas they are methylene-interrupted in LN. Some seed oil, such as tung oil and pomegranate seed oil, principally consist of CLN, accounting for 76.5% and 75.5%, respectively.CLN can be characterized using the combination of gas chromatography (GC), highperformance liquid chromatography (HPLC) and UV /VIS spectrophotomea-ic analysis. GC can separate the CLN from other fatty acids and HPLC can separate the individual CLN isomers.The conjugated triene formation has a maximum absorbency at 268 nm and the conjugated diene formation has an absorbency at 235 nm in UV spectrum.CLN was prepared from linseed oil by isomerization reaction in our present study. By treating at was isomerized and the product was purified by recrystallizing in the methanol. The GC and UV /VIS spectrophotometric analysis were used to characterize the obtained products. It was found that the a-LN in the linseed oil was converted to the corresponding conjugated diene acids and CLN. The GC analysis also showed that there formed about 20% CLN when reacting for 10h with 40% KOH/ethylene glycol.

  15. Novel conjugates of peptides and conjugated polymers for optoelectronics and neural interfaces

    Science.gov (United States)

    Bhagwat, Nandita

    Peptide-polymer conjugates are a novel class of hybrid materials that take advantage of each individual component giving the opportunity to generate materials with unique physical, chemical, mechanical, optical, and electronic properties. In this dissertation peptide-polymer conjugates for two different applications are discussed. The first set of peptide-polymer conjugates were developed as templates to study the intermolecular interactions between electroactive molecules by manipulating the intermolecular distances at nano-scale level. A PEGylated, alpha-helical peptide template was employed to effectively display an array of organic chromophores (oxadiazole containing phenylenevinylene oligomers, Oxa-PPV). Three Oxa-PPV chromophores were strategically positioned on each template, at distances ranging from 6 to 17 A from each other, as dictated by the chemical and structural properties of the peptide. The Oxa-PPV modified PEGylated helical peptides (produced via Heck coupling strategies) were characterized by a variety of spectroscopic methods. Electronic contributions from multiple pairs of chromophores on a scaffold were detectable; the number and relative positioning of the chromophores dictated the absorbance and emission maxima, thus confirming the utility of these polymer--peptide templates for complex presentation of organic chromophores. The rest of the thesis is focused on using poly(3,4-alkylenedioxythiophene) based conjugated polymers as coatings for neural electrodes. This thiophene derivative is of considerable current interest for functionalizing the surfaces of a wide variety of devices including implantable biomedical electronics, specifically neural bio-electrodes. Toward these ends, copolymer films of 3,4-ethylenedioxythiophene (EDOT) with a carboxylic acid functional EDOT (EDOTacid) were electrochemically deposited and characterized as a systematic function of the EDOTacid content (0, 25, 50, 75, and 100%). The chemical surface characterization

  16. Conjugated Linoleic Triacylglycerols Exhibit Superior Lymphatic Absorption Than Free Conjugate Linoleic Acids and Have Antiobesity Properties.

    Science.gov (United States)

    Woo, Hyunjoon; Chung, Min-Yu; Kim, Juyeon; Kong, Daecheol; Min, Jinyoung; Choi, Hee-Don; Choi, In-Wook; Kim, In-Hwan; Noh, Sang K; Kim, Byung Hee

    2016-05-01

    This study aimed to compare lymphatic absorption of conjugated linoleic acids (CLAs) in the triacylglycerol (TAG) or free fatty acid (FFA) form and to examine the antiobesity effects of different doses of CLAs in the TAG form in animals. Conjugated linoleic TAGs (containing 70.3 wt% CLAs; CLA-TAG) were prepared through lipase-catalyzed esterification of glycerol with commercial CLA mixtures (CLA-FFA). Lymphatic absorption of CLA-TAG and CLA-FFA was compared in a rat model of lymphatic cannulation. Greater amounts of cis-9,trans-11 and trans-10,cis-12 CLAs were detected in the collected lymph from a lipid emulsion containing CLA-TAG. This result suggests that CLA-TAG has greater capacity for lymphatic absorption than does CLA-FFA. The antiobesity efficacy of CLA-TAG at different doses was examined in mice with diet-induced obesity. A high-fat diet (HFD) for 12 weeks caused a significant increase in body weight and epididymal and retroperitoneal fat weights, which were significantly decreased by 2% dietary supplementation (w/w) with CLA-TAG. CLA-TAG at 2% significantly attenuated the HFD-induced upregulation of serum TAG, but led to hepatomegaly and exacerbated HFD-induced hypercholesterolemia. CLA-TAG at 1% significantly attenuated upregulation of retroperitoneal fat weight and significantly increased liver weight, which was decreased by the HFD. Nonetheless, the liver weight in group "HFD +1% CLA-TAG" was not significantly different from that of normal diet controls. CLA-TAG at 1% significantly reduced serum TAG levels and did not exacerbate HFD-induced hypercholesterolemia. Thus, 1% dietary supplementation with CLA-TAG reduces retroperitoneal fat weight without apparent hepatomegaly, a known side-effect of CLAs in mouse models of obesity. PMID:27081749

  17. Thin Films Formed from Conjugated Polymers with Ionic, Water-Soluble Backbones.

    Science.gov (United States)

    Voortman, Thomas P; Chiechi, Ryan C

    2015-12-30

    This paper compares the morphologies of films of conjugated polymers in which the backbone (main chain) and pendant groups are varied between ionic/hydrophilic and aliphatic/hydrophobic. We observe that conjugated polymers in which the pendant groups and backbone are matched, either ionic-ionic or hydrophobic-hydrophobic, form smooth, structured, homogeneous films from water (ionic) or tetrahydrofuran (hydrophobic). Mismatched conjugated polymers, by contrast, form inhomogeneous films with rough topologies. The polymers with ionic backbone chains are conjugated polyions (conjugated polymers with closed-shell charges in the backbone), which are semiconducting materials with tunable bad-gaps, not unlike uncharged conjugated polymers.

  18. Chemically optimized antimyosin Fab conjugates with chelating polymers: importance of the nature of the protein-polymer single site covalent bond for biodistribution and infarction localization.

    Science.gov (United States)

    Trubetskoy, V S; Narula, J; Khaw, B A; Torchilin, V P

    1993-01-01

    Murine antimyosin Fab fragment was conjugated with 111In-labeled N-terminal-modified DTPA-polylysine using three bifunctional reagents: N-hydroxysuccinimide esters of 3-(2-pyridyldithio)propionic acid (SPDP conjugate), 4-(maleimidomethyl)cyclohexanecarboxylic acid (SMCC conjugate) and bromoacetic acid (BrAc conjugate) for potential localization of experimental myocardial infarction. Using various antibody preparations and a rabbit acute myocardial infarction model the following parameters were observed: (1) an in vitro antigen binding activity of SPDP conjugate = SMCC conjugate > BrAc conjugate, (2) a blood clearance rate of SPDP conjugate > BrAc conjugate > SMCC conjugate, (3) a liver and splenic accumulation of SPDP conjugate > BrAc conjugate > SMCC conjugate, and (4) the infarcted tissue activity showed an accumulation of SMCC conjugate > SPDP conjugate > BrAc conjugate. This study exemplifies the importance of rational chemical design of antimyosin Fab-chelating polymer conjugate for improved target tissue localization in vivo.

  19. Conjugates of a photoactivated rhodamine with biopolymers for cell staining.

    Science.gov (United States)

    Zaitsev, Sergei Yu; Shaposhnikov, Mikhail N; Solovyeva, Daria O; Solovyeva, Valeria V; Rizvanov, Albert A

    2014-01-01

    Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids) are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD) has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan ("Chitosan-PFD") and histone H1 ("Histone H1.3-PFD"). The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK). Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes ("caged" dyes) for microscopic probing of biological objects. Thus, the synthesized "Chitosan-PFD" and "Histone H1-PFD" have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.

  20. Recent advances in the construction of antibody-drug conjugates

    Science.gov (United States)

    Chudasama, Vijay; Maruani, Antoine; Caddick, Stephen

    2016-02-01

    Antibody-drug conjugates (ADCs) comprise antibodies covalently attached to highly potent drugs using a variety of conjugation technologies. As therapeutics, they combine the exquisite specificity of antibodies, enabling discrimination between healthy and diseased tissue, with the cell-killing ability of cytotoxic drugs. This powerful and exciting class of targeted therapy has shown considerable promise in the treatment of various cancers with two US Food and Drug Administration approved ADCs currently on the market (Adcetris and Kadcyla) and approximately 40 currently undergoing clinical evaluation. However, most of these ADCs exist as heterogeneous mixtures, which can result in a narrow therapeutic window and have major pharmacokinetic implications. In order for ADCs to deliver their full potential, sophisticated site-specific conjugation technologies to connect the drug to the antibody are vital. This Perspective discusses the strategies currently used for the site-specific construction of ADCs and appraises their merits and disadvantages.

  1. Small angle scattering from protein/sugar conjugates

    Science.gov (United States)

    Jackson, Andrew; White, John

    2006-11-01

    The Maillard reaction between free amine groups on proteins and sugars is well known. We have examined the effect of the reaction of the casein group of milk proteins with sugars on their nanoscale structure and aggregation. The small angle neutron scattering from beta casein and sodium caseinate and their sugar conjugates have been studied as a function of solution concentration. At high conjugate concentration (greater than ca. 5 mg/ml) the addition of sugar reduces supra-micellar aggregation of the protein whilst at lower concentration, where the protein is expected to be deaggregated already, little effect is seen. Guinier analysis of the scattering data show a radius of gyration of around 75 A˚ for beta casein in solution and around 80 A˚ for the sucrose conjugate.

  2. Small angle scattering from protein/sugar conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Andrew [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)]. E-mail: ajj@nist.gov; White, John [Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)

    2006-11-15

    The Maillard reaction between free amine groups on proteins and sugars is well known. We have examined the effect of the reaction of the casein group of milk proteins with sugars on their nanoscale structure and aggregation. The small angle neutron scattering from beta casein and sodium caseinate and their sugar conjugates have been studied as a function of solution concentration. At high conjugate concentration (greater than ca. 5mg/ml) the addition of sugar reduces supra-micellar aggregation of the protein whilst at lower concentration, where the protein is expected to be deaggregated already, little effect is seen. Guinier analysis of the scattering data show a radius of gyration of around 75A-bar for beta casein in solution and around 80A-bar for the sucrose conjugate.

  3. Conjugates of a Photoactivated Rhodamine with Biopolymers for Cell Staining

    Science.gov (United States)

    Zaitsev, Sergei Yu.; Shaposhnikov, Mikhail N.; Solovyeva, Daria O.; Solovyeva, Valeria V.; Rizvanov, Albert A.

    2014-01-01

    Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids) are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD) has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan (“Chitosan-PFD”) and histone H1 (“Histone H1.3-PFD”). The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK). Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes (“caged” dyes) for microscopic probing of biological objects. Thus, the synthesized “Chitosan-PFD” and “Histone H1-PFD” have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy. PMID:25383365

  4. Conjugates of a Photoactivated Rhodamine with Biopolymers for Cell Staining

    Directory of Open Access Journals (Sweden)

    Sergei Yu. Zaitsev

    2014-01-01

    Full Text Available Conjugates of the photoactivated rhodamine dyes with biopolymers (proteins, polysaccharides, and nucleic acids are important tools for microscopic investigation of biological tissue. In this study, a precursor of the photoactivated fluorescent dye (PFD has been successfully used for staining of numerous mammalian cells lines and for conjugate formation with chitosan (“Chitosan-PFD” and histone H1 (“Histone H1.3-PFD”. The intensive fluorescence has been observed after photoactivation of these conjugates inside cells (A431, HaCaT, HEK239, HBL-100, and MDCK. Developed procedures and obtained data are important for further application of novel precursors of fluorescent dyes (“caged” dyes for microscopic probing of biological objects. Thus, the synthesized “Chitosan-PFD” and “Histone H1-PFD” have been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.

  5. FAST NAS-RIF ALGORITHM USING ITERATIVE CONJUGATE GRADIENT METHOD

    Directory of Open Access Journals (Sweden)

    A.M.Raid

    2014-04-01

    Full Text Available Many improvements on image enhancemen have been achieved by The Non-negativity And Support constraints Recursive Inverse Filtering (NAS-RIF algorithm. The Deterministic constraints such as non negativity, known finite support, and existence of blur invariant edges are given for the true image. NASRIF algorithms iterative and simultaneously estimate the pixels of the true image and the Point Spread Function (PSF based on conjugate gradients method. NAS-RIF algorithm doesn’t assume parametric models for either the image or the blur, so we update the parameters of conjugate gradient method and the objective function for improving the minimization of the cost function and the time for execution. We propose a different version of linear and nonlinear conjugate gradient methods to obtain the better results of image restoration with high PSNR.

  6. Progress towards meningitis prevention in the conjugate vaccines era

    Directory of Open Access Journals (Sweden)

    Cristina Aparecida Borges Laval

    2003-10-01

    Full Text Available Acute bacterial meningitis is an important cause of morbidity and mortality among children less than five years old. Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis are the most important agents of bacterial meningitis in developing countries. The development of the conjugate vaccines in the beginning of the 90's, especially type b H. influenzae (Hib, and more recently the heptavalent pneumococcal and the serogroup C meningococcal vaccines, have contributed directly to changes in the epidemiological profile of these invasive diseases (direct effect and of their carriage status (indirect effect. We review the impact of the Hib conjugate vaccine in Latin American countries, where this vaccine has been implemented, and the potential of pneumococcal and meningococcal conjugate vaccines for the reduction of meningitis worldwide. We also address constraints for the development and delivery of these vaccines and review new candidate state-of-the-art vaccines. The greatest challenge, undoubtedly, is to implement these vaccines worldwide, especially in the developing regions.

  7. Synthesis and Spectral Studies of CdTe–Dendrimer Conjugates

    Directory of Open Access Journals (Sweden)

    Ghosh Srabanti

    2009-01-01

    Full Text Available Abstract In order to couple high cellular uptake and target specificity of dendrimer molecule with excellent optical properties of semiconductor nanoparticles, the interaction of cysteine-capped CdTe quantum dots with dendrimer was investigated through spectroscopic techniques. NH2-terminated dendrimer molecule quenched the photoluminescence of CdTe quantum dots. The binding constants and binding capacity were calculated, and the nature of binding was found to be noncovalent. Significant decrease in luminescence intensity of CdTe quantum dots owing to noncovalent binding with dendrimer limits further utilization of these nanoassemblies. Hence, an attempt is made, for the first time, to synthesize stable, highly luminescent, covalently linked CdTe–Dendrimer conjugate in aqueous medium using glutaric dialdehyde (G linker. Conjugate has been characterized through Fourier transform infrared spectroscopy and transmission electron microscopy. In this strategy, photoluminescence quantum efficiency of CdTe quantum dots with narrow emission bandwidths remained unaffected after formation of the conjugate.

  8. Full Eulerian lattice Boltzmann model for conjugate heat transfer.

    Science.gov (United States)

    Hu, Yang; Li, Decai; Shu, Shi; Niu, Xiaodong

    2015-12-01

    In this paper a full Eulerian lattice Boltzmann model is proposed for conjugate heat transfer. A unified governing equation with a source term for the temperature field is derived. By introducing the source term, we prove that the continuity of temperature and its normal flux at the interface is satisfied automatically. The curved interface is assumed to be zigzag lines. All physical quantities are recorded and updated on a Cartesian grid. As a result, any complicated treatment near the interface is avoided, which makes the proposed model suitable to simulate the conjugate heat transfer with complex interfaces efficiently. The present conjugate interface treatment is validated by several steady and unsteady numerical tests, including pure heat conduction, forced convection, and natural convection problems. Both flat and curved interfaces are also involved. The obtained results show good agreement with the analytical and/or finite volume results. PMID:26764851

  9. Streamline upwind finite element method for conjugate heat transfer problems

    Institute of Scientific and Technical Information of China (English)

    Niphon Wansophark; Atipong Malatip; Pramote Dechaumphai; Yunming Chen

    2005-01-01

    This paper presents a combined finite element method for solving conjugate heat transfer problems where heat conduction in a solid is coupled with heat convection in viscous fluid flow. The streamline upwind finite element method is used for the analysis of thermal viscous flow in the fluid region, whereas the analysis of heat conduction in solid region is performed by the Galerkin method. The method uses the three-node triangular element with equal-order interpolation functions for all the variables of the velocity components,the pressure and the temperature. The main advantage of the proposed method is to consistently couple heat transfer along the fluid-solid interface. Three test cases, i.e. conjugate Couette flow problem in parallel plate channel, counter-flow in heat exchanger, and conjugate natural convection in a square cavity with a conducting wall, are selected to evaluate the efficiency of the present method.

  10. Microscopic and spectroscopic analysis of chitosan-DNA conjugates.

    Science.gov (United States)

    Agudelo, D; Kreplak, L; Tajmir-Riahi, H A

    2016-02-10

    Conjugations of DNA with chitosans 15 kD (ch-15), 100 kD (ch-100) and 200 kD (ch-200) were investigated in aqueous solution at pH 5.5-6.5. Multiple spectroscopic methods and atomic force microscopy (AFM) were used to locate the chitosan binding sites and the effect of polymer conjugation on DNA compaction and particle formation. Structural analysis showed that chitosan-DNA conjugation is mainly via electrostatic interactions through polymer cationic charged NH2 and negatively charged backbone phosphate groups. As polymer size increases major DNA compaction and particle formation occurs. At high chitosan concentration major DNA structural changes observed indicating a partial B to A-DNA conformational transition.

  11. Push-pull macrocycles: donor-acceptor compounds with paired linearly conjugated or cross-conjugated pathways.

    Science.gov (United States)

    Leu, Wade C W; Fritz, Amanda E; Digianantonio, Katherine M; Hartley, C Scott

    2012-03-01

    Two-dimensional π-systems are of current interest in the design of functional organic molecules, exhibiting unique behavior for applications in organic electronics, single-molecule devices, and sensing. Here we describe the synthesis and characterization of "push-pull macrocycles": electron-rich and electron-poor moieties linked by a pair of (matched) conjugated bridges. We have developed a two-component macrocyclization strategy that allows these structures to be synthesized with efficiencies comparable to acyclic donor-bridge-acceptor systems. Compounds with both cross-conjugated (m-phenylene) and linearly conjugated (2,5-thiophene) bridges have been prepared. As expected, the compounds undergo excitation to locally excited states followed by fluorescence from charge-transfer states. The m-phenylene-based systems exhibit slower charge-recombination rates presumably due to reduced electronic coupling through the cross-conjugated bridges. Interestingly, pairing the linearly conjugated 2,5-thiophene bridges also slows charge recombination. DFT calculations of frontier molecular orbitals show that the direct HOMO-LUMO transition is polarized orthogonal to the axis of charge transfer for these symmetrical macrocyclic architectures, reducing the electronic coupling. We believe the push-pull macrocycle design may be useful in engineering functional frontier molecular orbital symmetries.

  12. Effects of Polymer Conjugation on Hybridization Thermodynamics of Oligonucleic Acids.

    Science.gov (United States)

    Ghobadi, Ahmadreza F; Jayaraman, Arthi

    2016-09-15

    In this work, we perform coarse-grained (CG) and atomistic simulations to study the effects of polymer conjugation on hybridization/melting thermodynamics of oligonucleic acids (ONAs). We present coarse-grained Langevin molecular dynamics simulations (CG-NVT) to assess the effects of the polymer flexibility, length, and architecture on hybridization/melting of ONAs with different ONA duplex sequences, backbone chemistry, and duplex concentration. In these CG-NVT simulations, we use our recently developed CG model of ONAs in implicit solvent, and treat the conjugated polymer as a CG chain with purely repulsive Weeks-Chandler-Andersen interactions with all other species in the system. We find that 8-100-mer linear polymer conjugation destabilizes 8-mer ONA duplexes with weaker Watson-Crick hydrogen bonding (WC H-bonding) interactions at low duplex concentrations, while the same polymer conjugation has an insignificant impact on 8-mer ONA duplexes with stronger WC H-bonding. To ensure the configurational space is sampled properly in the CG-NVT simulations, we also perform CG well-tempered metadynamics simulations (CG-NVT-MetaD) and analyze the free energy landscape of ONA hybridization for a select few systems. We demonstrate that CG-NVT-MetaD simulation results are consistent with the CG-NVT simulations for the studied systems. To examine the limitations of coarse-graining in capturing ONA-polymer interactions, we perform atomistic parallel tempering metadynamics simulations at well-tempered ensemble (AA-MetaD) for a 4-mer DNA in explicit water with and without conjugation to 8-mer poly(ethylene glycol) (PEG). AA-MetaD simulations also show that, for a short DNA duplex at T = 300 K, a condition where the DNA duplex is unstable, conjugation with PEG further destabilizes DNA duplex. We conclude with a comparison of results from these three different types of simulations and discuss their limitations and strengths. PMID:27598692

  13. Novel synthetic (poly)glycerolphosphate-based antistaphylococcal conjugate vaccine.

    Science.gov (United States)

    Chen, Quanyi; Dintaman, Jay; Lees, Andrew; Sen, Goutam; Schwartz, David; Shirtliff, Mark E; Park, Saeyoung; Lee, Jean C; Mond, James J; Snapper, Clifford M

    2013-07-01

    Staphylococcal infections are a major source of global morbidity and mortality. Currently there exists no antistaphylococcal vaccine in clinical use. Previous animal studies suggested a possible role for purified lipoteichoic acid as a vaccine target for eliciting protective IgG to several Gram-positive pathogens. Since the highly conserved (poly)glycerolphosphate backbone of lipoteichoic acid is a major antigenic target of the humoral immune system during staphylococcal infections, we developed a synthetic method for producing glycerol phosphoramidites to create a covalent 10-mer of (poly)glycerolphosphate for potential use in a conjugate vaccine. We initially demonstrated that intact Staphylococcus aureus elicits murine CD4(+) T cell-dependent (poly)glycerolphosphate-specific IgM and IgG responses in vivo. Naive mice immunized with a covalent conjugate of (poly)glycerolphosphate and tetanus toxoid in alum plus CpG-oligodeoxynucleotides produced high secondary titers of serum (poly)glycerolphosphate-specific IgG. Sera from immunized mice enhanced opsonophagocytic killing of live Staphylococcus aureus in vitro. Mice actively immunized with the (poly)glycerolphosphate conjugate vaccine showed rapid clearance of staphylococcal bacteremia in vivo relative to mice similarly immunized with an irrelevant conjugate vaccine. In contrast to purified, natural lipoteichoic acid, the (poly)glycerolphosphate conjugate vaccine itself exhibited no detectable inflammatory activity. These data suggest that a synthetic (poly)glycerolphosphate-based conjugate vaccine will contribute to active protection against extracellular Gram-positive pathogens expressing this highly conserved backbone structure in their membrane-associated lipoteichoic acid. PMID:23649092

  14. High-conjugation-efficiency aqueous CdSe quantum dots.

    Science.gov (United States)

    Au, Giang H T; Shih, Wan Y; Shih, Wei-Heng

    2013-11-12

    Quantum dots (QDs) are photoluminescent nanoparticles that can be directly or indirectly coupled with a receptor such as an antibody to specifically image a target biomolecule such as an antigen. Recent studies have shown that QDs can be directly made at room temperature and in an aqueous environment (AQDs) with 3-mercaptopropionic acid (MPA) as the capping ligand without solvent and ligand exchange typically required by QDs made by the organic solvent routes (OQDs). In this study, we have synthesized CdSe AQDs and compared their conjugation efficiency and imaging efficacy with commercial carboxylated OQDs in HT29 colon cancer cells using a primary antibody-biotinylated secondary antibody-streptavidin (SA) sandwich. We showed that the best imaging condition for AQDs occurred when one AQD was bound with 3 ± 0.3 SA with a nominal SA/AQD ratio of 4 corresponding to an SA conjugation efficiency of 75 ± 7.5%. In comparison, for commercial CdSe-ZnS OQDs to achieve 2.7 ± 0.4 bound SAs per OQD for comparable imaging efficacy a nominal SA/OQD ratio of 80 was needed corresponding to an SA conjugation efficiency of 3.4 ± 0.5% for CdSe-ZnS OQDs. The more than 10 times better SA conjugation efficiency of the CdSe AQDs as compared to that of the CdSe-ZnS OQDs was attributed to more capping molecules on the AQD surface as a result of the direct aqueous synthesis. More capping molecules on the AQD surface also allowed the SA-AQD conjugate to be stable in cell culture medium for more than three days without losing their staining capability in a flowing cell culture medium. In contrast, SA-OQD conjugates aggregated in cell culture medium and in phosphate buffer saline solution over time. PMID:24151632

  15. Self-Assembled Conjugated Polymer Nanometer Scale Devices

    Institute of Scientific and Technical Information of China (English)

    Wenping Hu; Hiroshi Nakashima; Keiichi Torimitsu; Yunqi Liu; Daoben Zhu

    2005-01-01

    @@ 1Introduction Nanometer scale devices, as the next generation devices of electronics, have got a worldwide attention and rapid development recently. Simultaneously, conjugated polymers have been applied in organic electronics successfully because of their outstanding electronic-photonic properties. However, as far as we know few reports have dealt with the fabrication of nanometer scale devices by using conjugated polymers, although the combination of nanometer scale devices and polymers will not only extend conjugated polymers to Nanoelectronics, but also excavate the behaviors of polymer molecules at nano-molecular level, such as the electron transport through polymer molecules. One reason for this case is due to the lack of rigidity for most polymers.It results in the failure to bridge them between electrodes or to stand on substrates, therefore, fails to be characterized by scanning probe microscopy. Another reason is that the non-functionalized end-group of most polymers is impossible to graft on substrates through chemical bonds. Here, we introduce a self-assembled conjugated polymer can be used to fabricate nanodevices by self-assembly. The conjugated polymer is a derivative of poly(p-phenyleneethynylene)s (PPE) with thioacetyl end groups (Fig. 1). In general, it is known that for self-assembling ideal nanojunctions the materials should possess: a) conductivity, b) rigidity (for wiring and bridging between electrodes), and c) connectivity (for covalent attachment to metallic or semiconductor solid surfaces). PPE provides good conductivity owing to its special π-conjugated configuration. It is also believed that in principle PPE molecules possess rigidity because of the presence of the triple bond in their molecules,which prevents the rotation of adjacent phenyl rings with respect to each other.

  16. Side Chain Engineering in Solution-Processable Conjugated Polymers

    KAUST Repository

    Mei, Jianguo

    2014-01-14

    Side chains in conjugated polymers have been primarily utilized as solubilizing groups. However, these side chains have roles that are far beyond. We advocate using side chain engineering to tune a polymer\\'s physical properties, including absorption, emission, energy level, molecular packing, and charge transport. To date, numerous flexible substituents suitable for constructing side chains have been reported. In this Perspective article, we advocate that the side chain engineering approach can advance better designs for next-generation conjugated polymers. © 2013 American Chemical Society.

  17. A REVISED CONJUGATE GRADIENT PROJECTION ALGORITHM FOR INEQUALITY CONSTRAINED OPTIMIZATIONS

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Lian-sheng Zhang; Yi-fan Xu

    2005-01-01

    A revised conjugate gradient projection method for nonlinear inequality constrained optimization problems is proposed in the paper, since the search direction is the combination of the conjugate projection gradient and the quasi-Newton direction. It has two merits. The one is that the amount of computation is lower because the gradient matrix only needs to be computed one time at each iteration. The other is that the algorithm is of global convergence and locally superlinear convergence without strict complementary condition under some mild assumptions. In addition the search direction is explicit.

  18. Imaging GABAc Receptors with Ligand-Conjugated Quantum Dots

    Directory of Open Access Journals (Sweden)

    Ian D. Tomlinson

    2007-01-01

    Full Text Available We report a methodology for labeling the GABAc receptor on the surface membrane of intact cells. This work builds upon our earlier work with serotonin-conjugated quantum dots and our studies with PEGylated quantum dots to reduce nonspecific binding. In the current approach, a PEGylated derivative of muscimol was synthesized and attached via an amide linkage to quantum dots coated in an amphiphilic polymer derivative of a modified polyacrylamide. These conjugates were used to image GABAC receptors heterologously expressed in Xenopus laevis oocytes.

  19. Poly(trimethylsilylcyclooctatetraene): A soluble conjugated polyacetylene via olefin metathesis

    Energy Technology Data Exchange (ETDEWEB)

    Ginsburg, E.J.; Gorman, C.B.; Grubbs, R.H.; Marder, S.R. (California Institute of Technology, Pasadena (USA))

    1989-09-13

    highly conjugated polymers, such as polyacetylene, polythiophene, and poly(p-phenylene vinylene), have been the subject of intensive research due to their intriguing optical and electronic properties. These parent systems are highly desirable for experimental and theoretical studies due to their simplicity. Their intractability, however, has made characterization an arduous task, and insolubility has severely limited their applications. Researchers have successfully circumvented these obstacles by synthesizing soluble alkyl- and alkoxy-substituted polythiphenes and poly(p-phenylene vinylenes). Analogous soluble highly conjugated polyacetylene derivatives have proven more elusive. The authors report here the synthesis of such a polymer using ring-opening metathesis polymerization (ROMP).

  20. Conjugate heat and mass transfer in heat mass exchanger ducts

    CERN Document Server

    Zhang, Li-Zhi

    2013-01-01

    Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts bridges the gap between fundamentals and recent discoveries, making it a valuable tool for anyone looking to expand their knowledge of heat exchangers. The first book on the market to cover conjugate heat and mass transfer in heat exchangers, author Li-Zhi Zhang goes beyond the basics to cover recent advancements in equipment for energy use and environmental control (such as heat and moisture recovery ventilators, hollow fiber membrane modules for humidification/dehumidification, membrane modules for air purification, desi

  1. Biophysical characterization of a model antibody drug conjugate.

    Science.gov (United States)

    Arakawa, Tsutomu; Kurosawa, Yasunori; Storms, Michael; Maruyama, Toshiaki; Okumura, C J; Maluf, Nasib Karl

    2016-01-01

    Antibody drug conjugates (ADC) are important next-generation biopharmaceuticals and thus require stringent structure characterization as is the case for monoclonal antibodies. We have tested several biophysical techniques, i.e., circular dichroism, analytical ultracentrifugation, differential scanning calorimetry and fluorescence spectroscopy, to characterize a fluorescein-labeled monoclonal antibody as a model ADC. These techniques indicated possible small structure and stability changes by the conjugation, while largely retaining the tertiary structure of the antibody, consistent with unaltered biological activities. Thus, the above biophysical techniques are effective at detecting changes in the structural properties of ADC. PMID:27534450

  2. Synthesis and photocurrent response of porphyrin-containing conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jinling; LI Binsong; BO Zhishan

    2006-01-01

    Porphyrin-containing conjugated polymers with fluorene or carbazole as spacer groups were prepared by Sonogashira cross-coupling reactions. The polymers were of high molecular weight and the flexible alkyl chains on fluorene or carbazole units made the conjugated polymers soluble in common organic solvents, such as THF and methylene chloride. The polymers could form high quality durable films from solution casting. Their optical and photocurrent responsive properties were investigated. It was found that the photocurrent response was directly proportional to the content of porphyrin. The incorporation of carbazole units into the polymer chains also gave positive contribution to the photocurrent generation in some extent.

  3. Emerging applications of conjugated polymers in molecular imaging.

    Science.gov (United States)

    Li, Junwei; Liu, Jie; Wei, Chen-Wei; Liu, Bin; O'Donnell, Matthew; Gao, Xiaohu

    2013-10-28

    In recent years, conjugated polymers have attracted considerable attention from the imaging community as a new class of contrast agent due to their intriguing structural, chemical, and optical properties. Their size and emission wavelength tunability, brightness, photostability, and low toxicity have been demonstrated in a wide range of in vitro sensing and cellular imaging applications, and have just begun to show impact in in vivo settings. In this Perspective, we summarize recent advances in engineering conjugated polymers as imaging contrast agents, their emerging applications in molecular imaging (referred to as in vivo uses in this paper), as well as our perspectives on future research.

  4. Peptide π-Electron Conjugates: Organic Electronics for Biology?

    Science.gov (United States)

    Ardoña, Herdeline Ann M; Tovar, John D

    2015-12-16

    Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

  5. Functionalized Conjugated Polyelectrolytes for Biological Sensing and Imaging.

    Science.gov (United States)

    Zhan, Ruoyu; Liu, Bin

    2016-06-01

    Conjugated polyelectrolytes (CPEs) are macromolecules with highly delocalized π-conjugated backbones and charged side chains, which are unique types of active materials, with wide applications in optoelectronics, sensing, imaging, and therapy. By attaching specific groups (e.g., recognition elements, magnetic resonance (MR) contrast agents, gene carriers, and drugs) to the side chain or backbone of CPEs, functionalized CPEs have been developed and used for specific biological applications. In this account, we summarize the recent progress of functionalized CPEs with respect to their synthesis and biomedical applications. Future perspectives are also discussed at the end. PMID:27230631

  6. Convexity of Spheres in a Manifold without Conjugate Points

    Indian Academy of Sciences (India)

    Akhil Ranjan; Hemangi Shah

    2002-11-01

    For a non-compact, complete and simply connected manifold without conjugate points, we prove that if the determinant of the second fundamental form of the geodesic spheres in is a radial function, then the geodesic spheres are convex. We also show that if is two or three dimensional and without conjugate points, then, at every point there exists a ray with no focal points on it relative to the initial point of the ray. The proofs use a result from the theory of vector bundles combined with the index lemma.

  7. Conjugated Linoleic Acids Reduce Body Fat in Healthy Postmenopausal Women

    DEFF Research Database (Denmark)

    Raff, M.; Tholstrup, T.; Toubro, S.;

    2009-01-01

    Isomers of conjugated linoleic acids (CLA) reduce fat mass FM) and increase insulin sensitivity in some, but not all, murine studies. In humans, this effect is still debatable. In this study, we compared the effect of 2 CLA supplements on total and regional FM assessed by dual energy X-ray absorp......Isomers of conjugated linoleic acids (CLA) reduce fat mass FM) and increase insulin sensitivity in some, but not all, murine studies. In humans, this effect is still debatable. In this study, we compared the effect of 2 CLA supplements on total and regional FM assessed by dual energy X...

  8. Amphiphilic Cyanine-Platinum Conjugates as Fluorescent Nanodrugs.

    Science.gov (United States)

    Sun, Tingting; Li, Zhensheng; Xie, Zhigang; Jing, Xiabin

    2016-01-01

    Two fluorescent nanomedicines based on small molecular cyanine-platinum conjugates have been prepared via a nanoprecipitation method and characterized by transmission electron microscopy (TEM) as well as dynamic light scattering (DLS). The conjugates exhibited an enhanced fluorescence in their nanoparticle formulation compared to that in solution. The nanomedicines could be endocytosed by cancer cells as revealed by confocal laser scanning microscopy (CLSM) and showed high cellular proliferation inhibition. Fluorescent platinum nanomedicines prepared directly from small molecules could be an alternative strategy for developing new drugs with simultaneous cellular imaging and cancer therapy functions. PMID:26556434

  9. Light-emitting conjugated polymers with microporous network architecture: interweaving scaffold promotes electronic conjugation, facilitates exciton migration, and improves luminescence.

    Science.gov (United States)

    Xu, Yanhong; Chen, Long; Guo, Zhaoqi; Nagai, Atsushi; Jiang, Donglin

    2011-11-01

    Herein we report a strategy for the design of highly luminescent conjugated polymers by restricting rotation of the polymer building blocks through a microporous network architecture. We demonstrate this concept using tetraphenylethene (TPE) as a building block to construct a light-emitting conjugated microporous polymer. The interlocked network successfully restricted the rotation of the phenyl units, which are the major cause of fluorescence deactivation in TPE, thus providing intrinsic luminescence activity for the polymers. We show positive "CMP effects" that the network promotes π-conjugation, facilitates exciton migration, and improves luminescence activity. Although the monomer and linear polymer analogue in solvents are nonemissive, the network polymers are highly luminescent in various solvents and the solid state. Because emission losses due to rotation are ubiquitous among small chromophores, this strategy can be generalized for the de novo design of light-emitting materials by integrating the chromophores into an interlocked network architecture.

  10. Bioactivation of cysteine conjugates of 1-nitropyrene oxides by cysteine conjugate beta-lyase purified from Peptostreptococcus magnus.

    OpenAIRE

    Kataoka, K; Kinouchi, T; Akimoto, S; Ohnishi, Y

    1995-01-01

    To determine the role of cysteine conjugate beta-lyase (beta-lyase) in the metabolism of mutagenic nitropolycyclic aromatic hydrocarbons, we determined the effect of beta-lyase on the mutagenicities and DNA binding of cysteine conjugates of 4,5-epoxy-4,5-dihydro-1-nitropyrene (1-NP 4,5-oxide) and 9,10-epoxy-9,10-dihydro-1-nitropyrene (1-NP 9,10-oxide), which are detoxified metabolites of the mutagenic compound 1-nitropyrene. We purified beta-lyase from Peptostreptococcus magnus GAI0663, since...

  11. New type of antibody-enzyme conjugate which specifically kills Candida albicans.

    OpenAIRE

    Okuda, K; Ishiwara, K; Noguchi, Y.; Takahashi, T.; Tadokoro, I

    1980-01-01

    A new type of antibody-enzyme conjugate was made, and its possible application to Candida infection was studied. Both lactoperoxidase and xanthine oxidase were conjugated to specific antibody against Candida albicans. In vitro microbiocidal activity of the new antibody-enzyme conjugate, when incubated together with xanthine and minute amount of halides, showed a remarkable level of candidacidal ability. When the new antibody-enzyme conjugate was given to Candida-infected mice, followed by inj...

  12. Uncovering the Prevalence and Diversity of Integrating Conjugative Elements in Actinobacteria

    OpenAIRE

    Mariana Gabriela Ghinet; Eric Bordeleau; Julie Beaudin; Ryszard Brzezinski; Sébastien Roy; Vincent Burrus

    2011-01-01

    Horizontal gene transfer greatly facilitates rapid genetic adaptation of bacteria to shifts in environmental conditions and colonization of new niches by allowing one-step acquisition of novel functions. Conjugation is a major mechanism of horizontal gene transfer mediated by conjugative plasmids and integrating conjugative elements (ICEs). While in most bacterial conjugative systems DNA translocation requires the assembly of a complex type IV secretion system (T4SS), in Actinobacteria a sing...

  13. Novel Curcumin Diclofenac Conjugate Enhanced Curcumin Bioavailability and Efficacy in Streptococcal Cell Wall-induced Arthritis

    OpenAIRE

    S.K. Jain; Gill, M. S.; Pawar, H. S.; Sarasija Suresh

    2014-01-01

    Curcumin-diclofenac conjugate as been synthesized by esterification of phenolic group of curcumin with the acid moiety of diclofenac, and characterized by mass spectrometry, NMR, FTIR, DSC, thermogravimetric analysis and X-ray diffraction analysis. The relative solubility of curcumin-diclofenac conjugate, curcumin and diclofenac; stability of curcumin-diclofenac conjugate in intestinal extract; permeability study of curcumin-diclofenac conjugate using the everted rat intestinal sac method; st...

  14. Sub-nanometer control of the interlayer spacing in thin films of intercalated rodlike conjugated molecules.

    Science.gov (United States)

    Vogel, Jörn-Oliver; Salzmann, Ingo; Opitz, Ricarda; Duhm, Steffen; Nickel, Bert; Rabe, Jürgen P; Koch, Norbert

    2007-12-27

    Organic molecular beam co-deposition of rodlike conjugated molecules with an alkylated analogue resulted in thin film structures with layers of alternating semiconducting (conjugated molecular parts) and insulating (alkyl parts) character. By varying the alkylated molecule ratio, we could adjust the distance between conjugated layers with sub-nanometer precision, exploiting the mechanical flexibility of the alkyl chains. Furthermore, due to mutual molecular intercalation, mixed layers containing two conjugated moieties with vastly different electronic properties could be fabricated.

  15. Effects of Sperm Conjugation and Dissociation on Sperm Viability In Vitro

    OpenAIRE

    Higginson, Dawn M.; Henn, Kali R. H.

    2012-01-01

    Sperm conjugation is an unusual variation in sperm behavior where two or more spermatozoa physically unite for motility or transport through the female reproductive tract. Conjugation has frequently been interpreted as sperm cooperation, including reproductive altruism, with some sperm advancing their siblings toward the site of fertilization while ostensibly forfeiting their own ability to fertilize through damage incurred during conjugate break-up. Conversely, conjugation has been proposed ...

  16. Synthesis and Antiproliferative Activity of Silybin Conjugates with Salinomycin and Monensin.

    Science.gov (United States)

    Antoszczak, Michał; Klejborowska, Greta; Kruszyk, Monika; Maj, Ewa; Wietrzyk, Joanna; Huczyński, Adam

    2015-12-01

    Aiming at development of multitarget drugs for the anticancer treatment, new silybin (SIL) conjugates with salinomycin (SAL) and monensin (MON) were synthesized, in mild esterification conditions, and their antiproliferative activity was studied. The conjugates obtained exhibit anticancer activity against HepG2, LoVo and LoVo/DX cancer cell lines. Moreover, MON-SIL conjugate exhibits higher anticancer potential and better selectivity than the corresponding SAL-SIL conjugate.

  17. Optimization of PAMAM-gold nanoparticle conjugation for gene therapy.

    Science.gov (United States)

    Figueroa, Elizabeth R; Lin, Adam Y; Yan, Jiaxi; Luo, Laureen; Foster, Aaron E; Drezek, Rebekah A

    2014-02-01

    The development of efficient and biocompatible non-viral vectors for gene therapy remains a great challenge, and exploiting the properties of both nanoparticle carriers and cationic polymers is an attractive approach. In this work, we have developed gold nanoparticle (AuNP) polyamidoamine (PAMAM) conjugates for use as non-viral transfection agents. AuPAMAM conjugates were prepared by crosslinking PAMAM dendrimers to carboxylic-terminated AuNPs via EDC and sulfo-NHS chemistry. EDC and sulfo-NHS have been utilized widely and in numerous applications such as amino acid coupling; however, their use in the coupling of PAMAM dendrimers to AuNPs presents new challenges to form effective and stable constructs for delivery that have not yet been examined. Enhanced colloidal stability and DNA condensation ability was established by probing two critical synthetic parameters: the reaction rate of the PAMAM crosslinking step, and the amine to carboxyl ratio. Based on this work, increasing the amine to carboxyl ratio during conjugation of PAMAM onto AuNPs yielded the optimal vector with respect to colloidal stability and transfection efficiency in vitro. AuPAMAM conjugates present attractive candidates for non-viral gene delivery due to their commercial availability, ease of fabrication and scale-up, high yield, high transfection efficiency and low cytotoxicity. PMID:24286816

  18. Morphological Priming by Itself: A Study of Portuguese Conjugations

    Science.gov (United States)

    Verissimo, Joao; Clahsen, Harald

    2009-01-01

    Does the language processing system make use of abstract grammatical categories and representations that are not directly visible from the surface form of a linguistic expression? This study examines stem-formation processes and conjugation classes, a case of "pure" morphology that provides insight into the role of grammatical structure in…

  19. Mn(lll)-Mediated Chlorination of Conjugated Ketones

    Institute of Scientific and Technical Information of China (English)

    刘兴超; 王璐; 邹建平

    2011-01-01

    Mn(III)-Cl formed by the reaction of Mn(OAc)3 and hydrochloric acid in situ, reacted with α,β-unsaturated ketones readily to afford α,β-dichloroketones in good yields under mild conditions. The products are key precursors for synthesis of conjugated alkynones and other organic compounds.

  20. Homology among tet determinants in conjugative elements of streptococci

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.D.; Hazum, S.; Guild, W.R.

    1981-10-01

    A mutation to tetracycline sensitivity in a resistant strain of Streptococcus pneumoniae was shown by several criteria to be due to a point mutation in the conjugative o(cat-tet) element found in the chromosomes of strains derived from BM6001, a clinical strain resistant to tetracycline and chloramphenicol. Strains carrying the mutation were transformed back to tetracycline resistance with the high efficiency of a point marker by donor deoxyribonucleic acids from its ancestral strain and from nine other clinical isolates of pneumococcus and by deoxyribonucleic acids from Group D Streptococcus faecalis and Group B Streptococcus agalactiae strains that also carry conjugative tet elements in their chromosomes. It was not transformed to resistance by tet plasmid deoxyribonucleic acids from either gram-negative or gram-positive species, except for one that carried transposon TN916, the conjugative tet element present in the chromosomes of some S. faecalis strains. The results showed that the tet determinants in conjugative elements of several streptococcal species share a high degree of deoxyribonucleic acid sequence homology and suggested that they differ from other tet genes.

  1. Bacteriophages Limit the Existence Conditions for Conjugative Plasmids

    Science.gov (United States)

    Wood, A. Jamie; Dytham, Calvin; Pitchford, Jonathan W.; Truman, Julie; Spiers, Andrew; Paterson, Steve; Brockhurst, Michael A.

    2015-01-01

    ABSTRACT Bacteriophages are a major cause of bacterial mortality and impose strong selection on natural bacterial populations, yet their effects on the dynamics of conjugative plasmids have rarely been tested. We combined experimental evolution, mathematical modeling, and individual-based simulations to explain how the ecological and population genetics effects of bacteriophages upon bacteria interact to determine the dynamics of conjugative plasmids and their persistence. The ecological effects of bacteriophages on bacteria are predicted to limit the existence conditions for conjugative plasmids, preventing persistence under weak selection for plasmid accessory traits. Experiments showed that phages drove faster extinction of plasmids in environments where the plasmid conferred no benefit, but they also revealed more complex effects of phages on plasmid dynamics under these conditions, specifically, the temporary maintenance of plasmids at fixation followed by rapid loss. We hypothesized that the population genetic effects of bacteriophages, specifically, selection for phage resistance mutations, may have caused this. Further mathematical modeling and individual-based simulations supported our hypothesis, showing that conjugative plasmids may hitchhike with phage resistance mutations in the bacterial chromosome. PMID:26037122

  2. Abnormal glutathione conjugation in patients with tyrosinaemia type I

    NARCIS (Netherlands)

    Bergman, DJW; PollThe, BT; Smit, GPA; Breimer, DD; Duran, M; Smeitink, JAM

    1997-01-01

    Previous studies have suggested that tyrosinaemia type I may be associated with reduced glutathione availability due to conjugation of tyrosinaemia-associated reactive intermediates with glutathione. In the present study, the glutathione/glutathione S-transferase system of two tyrosinaemia patients

  3. Amphiphilic phthalocyanine-cyclodextrin conjugates for cancer photodynamic therapy.

    Science.gov (United States)

    Lourenço, Leandro M O; Pereira, Patrícia M R; Maciel, Elisabete; Válega, Mónica; Domingues, Fernando M J; Domingues, Maria R M; Neves, Maria G P M S; Cavaleiro, José A S; Fernandes, Rosa; Tomé, João P C

    2014-08-01

    Three phthalocyanines (Pcs) conjugated with α-, β- and γ-cyclodextrins (CDs) were prepared and their application as photosensitizer (PS) agents was assessed by photophysical, photochemical and in vitro photobiological studies. The photoactivity of Pc-α-CD and Pc-γ-CD ensures their potential as PDT drugs against UM-UC-3 human bladder cancer cells. PMID:24943806

  4. Adaptive Regularization of Neural Networks Using Conjugate Gradient

    DEFF Research Database (Denmark)

    Goutte, Cyril; Larsen, Jan

    1998-01-01

    Andersen et al. (1997) and Larsen et al. (1996, 1997) suggested a regularization scheme which iteratively adapts regularization parameters by minimizing validation error using simple gradient descent. In this contribution we present an improved algorithm based on the conjugate gradient technique...

  5. Parallel conjugate gradient algorithms for manipulator dynamic simulation

    Science.gov (United States)

    Fijany, Amir; Scheld, Robert E.

    1989-01-01

    Parallel conjugate gradient algorithms for the computation of multibody dynamics are developed for the specialized case of a robot manipulator. For an n-dimensional positive-definite linear system, the Classical Conjugate Gradient (CCG) algorithms are guaranteed to converge in n iterations, each with a computation cost of O(n); this leads to a total computational cost of O(n sq) on a serial processor. A conjugate gradient algorithms is presented that provide greater efficiency using a preconditioner, which reduces the number of iterations required, and by exploiting parallelism, which reduces the cost of each iteration. Two Preconditioned Conjugate Gradient (PCG) algorithms are proposed which respectively use a diagonal and a tridiagonal matrix, composed of the diagonal and tridiagonal elements of the mass matrix, as preconditioners. Parallel algorithms are developed to compute the preconditioners and their inversions in O(log sub 2 n) steps using n processors. A parallel algorithm is also presented which, on the same architecture, achieves the computational time of O(log sub 2 n) for each iteration. Simulation results for a seven degree-of-freedom manipulator are presented. Variants of the proposed algorithms are also developed which can be efficiently implemented on the Robot Mathematics Processor (RMP).

  6. Some properties of charge-conjugated spinors in D dimensions

    CERN Document Server

    D'Andrade, M A

    1995-01-01

    Spinors for an arbitrary Minkowski space with signature (t, s) are reassessed in connection with D-dimensional free Dirac action. The possibility of writing down kinetic and mass terms for charge-conjugated spinors is discussed in terms of the number of time-like directions of the space-time.

  7. Maternal Conjugal Multiplicity and Child Development in Rural Jamaica

    Science.gov (United States)

    Dreher, Melanie; Hudgins, Rebekah

    2010-01-01

    Using field-based observations and standardized measures of the home environment and child development, the authors followed 59 rural Jamaican women and their offspring from birth to age 5. The findings suggest that conjugal multiplicity, a female reproductive pattern characterized by multiple unions, maternal unmarried status, and absent father,…

  8. Beta-conjugates of real algebraic numbers as Puiseux expansions

    CERN Document Server

    Verger-Gaugry, Jean-Louis

    2011-01-01

    The beta-conjugates of a base of numeration $\\beta > 1$, $\\beta$ being a Parry number, were introduced by Boyd, in the context of the R\\'enyi-Parry dynamics of numeration system and the beta-transformation. These beta-conjugates are canonically associated with $\\beta$. Let $\\beta > 1$ be a real algebraic number. A more general definition of the beta-conjugates of $\\beta$ is introduced in terms of the Parry Upper function $f_{\\beta}(z)$ of the beta-transformation. We introduce the concept of a germ of curve at $(0,1/\\beta) \\in \\mathbb{C}^{2}$ associated with $f_{\\beta}(z)$ and the reciprocal of the minimal polynomial of $\\beta$. This germ is decomposed into irreducible elements according to the theory of Puiseux, gathered into conjugacy classes. The beta-conjugates of $\\beta$, in terms of the Puiseux expansions, are given a new equivalent definition in this new context. If $\\beta$ is a Parry number the (Artin-Mazur) dynamical zeta function $\\zeta_{\\beta}(z)$ of the beta-transformation, simply related to $f_{\\b...

  9. PROPERTIES AND ALGORITHM ON PRECONDITIONED CONJUGATE GRADIENT METHOD

    Institute of Scientific and Technical Information of China (English)

    田伶改

    2004-01-01

    Some properties of the preconditioned gradient conjugate method are given.It may happen that loss of significant digits, when the norm of residual is very small. To avoid this, a variant algorithm which does not use the residual is put forward.

  10. Synthesis of regioregular pentacene-containing conjugated polymers

    KAUST Repository

    Okamoto, Toshihiro

    2011-01-01

    We report the synthesis and characterization of a new class of regioregular pentacene-containing conjugated polymers via our synthetic routes reported previously. We found that our regioregular pentacene polymers showed improved ordering than their regiorandom counterpart as well as ambipolar OFET performance. © 2011 The Royal Society of Chemistry.

  11. RPM peptide conjugated bioreducible polyethylenimine targeting invasive colon cancer.

    Science.gov (United States)

    Lee, Yeong Mi; Lee, Duhwan; Kim, Jihoon; Park, Hansoo; Kim, Won Jong

    2015-05-10

    CPIEDRPMC (RPM) peptide is a peptide that specifically targets invasive colorectal cancer, which is one of the leading causes of cancer-related deaths worldwide. In this study, we exploited RPM peptide as a targeting ligand to produce a novel and efficient gene delivery system that could potentially be used to treat invasive colon cancer. In order to achieve enhanced specificity to colon cancer cells, the RPM peptide was conjugated to a bioreducible gene carrier consisting of a reducible moiety of disulfide-crosslinked low molecular weight polyethylenimine, IR820 dye, and polyethylene glycol. Here, we examined the physiochemical properties, cytotoxicity, in vitro transfection efficiency, and in vivo biodistribution of the RPM-conjugated polyplex. Our results showed that the RPM-conjugated gene carrier formed a compact polyplex with pDNA that had low toxicity. Furthermore, the RPM-conjugated polymer not only had higher cellular uptake in invasive colon cancer than the non-targeted polymer, but also showed enhanced transfection efficiency in invasive colon cancer cells in vitro and in vivo.

  12. A CLASS OF NONMONOTONE CONJUGATE GRADIENT METHODS FOR NONCONVEX FUNCTIONS

    Institute of Scientific and Technical Information of China (English)

    LiuYun; WeiZengxin

    2002-01-01

    This paper discusses the global convergence of a class of nonmonotone conjugate gradient methods (NM methods) for nonconvex object functions. This class of methods includes the nonmonotone counterpart of modified Polak-Ribiere method and modified Hestenes-Stiefel method as special cases.

  13. Propargylamine-isothiocyanate reaction: efficient conjugation chemistry in aqueous media

    DEFF Research Database (Denmark)

    Viart, Helene Marie-France; Larsen, T. S.; Tassone, Chiara;

    2014-01-01

    A coupling reaction between secondary propargyl amines and isothiocyanates in aqueous media is described. The reaction is high-yielding and affords cyclized products within 2-24 h. A functionalized ether lipid was synthesized in 8 steps, formulated as liposomes with POPC and conjugated to FITC un...

  14. Nanobody-photosensitizer conjugates for targeted photodynamic therapy

    NARCIS (Netherlands)

    Heukers, Raimond; van Bergen en Henegouwen, P; Santos Oliveira, Sabrina

    2014-01-01

    Photodynamic therapy (PDT) induces cell death through light activation of a photosensitizer (PS). Targeted delivery of PS via monoclonal antibodies has improved tumor selectivity. However, these conjugates have long half-lives, leading to relatively long photosensitivity in patients. In an attempt t

  15. Photorefractive dynamic holography using self-pumped phase conjugate beam

    Indian Academy of Sciences (India)

    Arun Anand; C S Narayanamurthy

    2006-03-01

    Dynamic holography in photorefractive materials using self-pumped phase conjugate beam of the object beam itself as the other writing beam is proposed. Our detailed theoretical analysis shows four-fold increase in the diffraction efficiency of dynamic holograms if recorded using this geometry even in photorefractive crystal like BTO (having low optical activity) without applying external field. Detailed theoretical analysis is given.

  16. Prostaglandin phospholipid conjugates with unusual biophysical and cytotoxic properties

    DEFF Research Database (Denmark)

    Pedersen, Palle Jacob; Adolph, Sidsel K.; Andresen, Thomas Lars;

    2010-01-01

    in an aqueous buffer and both phospholipids are hydrolyzed by phospholipase A(2), but with different conversion rates and extent of hydrolysis. The cytotoxicity was evaluated in HT-29 and Colo205 cells and the conjugates induced cell death in the presence of phospholipase A(2) and surprisingly also...

  17. Two novel conjugative plasmids from a single strain of Sulfolobus

    NARCIS (Netherlands)

    Erauso, G.; Stedman, K.M.; Werken, van de H.J.G.; Zillig, W.; Oost, van der J.

    2006-01-01

    Two conjugative plasmids (CPs) were isolated and characterized from the same 'Sulfolobus islandicus' strain, SOG2/4, The plasmids were separated from each other and transferred into Sulfolobus soltataricus. One has a high copy number and is not stable (pSOG1) whereas the other has a low copy number

  18. Synthesis and characterization of nido-carborane-cobalamin conjugates

    International Nuclear Information System (INIS)

    Three vitamin B12 (cyanocobalamin) conjugates bearing one nido-carborane molecule or two nido-carborane molecules linked to the propionamide side chains via a four carbon linker have been synthesized. Reaction of o-carboranoylchloride with 1,4-diaminobutane in pyridine produced nido-carboranoyl(4-amidobutyl)amine, which was linked to the b- and d-monocarboxylic acids and the b,d-dicarboxylic acid of cyanocobalamin. Mass spectrometry analysis as well as 11B nuclear magnetic resonance demonstrated that during the reaction of o-carboranonylchloride with diaminobutane one of the boron atoms was eliminated. In vitro biological activity of the cyanocobalamin-nido-carborane conjugates was assessed by the unsaturated vitamin B12 binding capacity assay. When compared with 57Co cyanocobalamin, the biological activity of cyanocobalamin-b-nido-carborane, cyanocobalamin-d-nido-carborane, and cyanocobalamin-b-d-bis-nido-carborane conjugates were 92.93%, 35.75%, and 37.02%, respectively. These findings suggest that the 10B cobalamin conjugates might be useful agents in treating malignant tumors via neutron capture therapy

  19. Fullerene–biomolecule conjugates and their biomedicinal applications

    Directory of Open Access Journals (Sweden)

    Yang X

    2013-12-01

    Full Text Available Xinlin Yang,1 Ali Ebrahimi,1 Jie Li,1,2 Quanjun Cui11Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, USA; 2School of Materials Science, Beijing Institute of Technology, Beijing, People's Republic of ChinaAbstract: Fullerenes are among the strongest antioxidants and are characterized as "radical sponges." The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene–biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene–biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene–biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest.Keywords: fullerene, amino acid, peptide, oligonucleotide, sugar, ester

  20. Development of Vi conjugate - a new generation of typhoid vaccine.

    Science.gov (United States)

    Szu, Shousun Chen

    2013-11-01

    Typhoid fever remains to be a serious disease burden worldwide with an estimated annual incidence about 20 million. The licensed vaccines showed moderate protections and have multiple deficiencies. Most important of all, none of the licensed typhoid vaccines demonstrated protection for children under 5 years old. These limitations impeded successful implementation of typhoid vaccination programs. To improve immunogenicity Vi was conjugated to rEPA, a recombinant exoprotein A from Pseudomonas aeruginosa. Vi-rEPA showed higher and longer lasting anti-Vi IgG in adults and children than Vi alone in high endemic areas. In school-age children and adults, the immunity persisted more than 8 years. In a double-blind, placebo-controlled and randomized efficacy trial in 2- to 5-year-old children, Vi-rEPA conferred 89% protective efficacy against typhoid fever and the protection lasted at least 4 years. When given concomitantly with infant routine vaccines, Vi-rEPA was safe, immunogenic and showed no interference with the routine vaccines. Vi conjugate vaccine was also attempted and successfully demonstrated by several other laboratories and manufactures. Using either rEPA or different carrier proteins, such as diphtheria or tetanus toxoid, recombinant diphtheria toxin (CRM197), the Vi conjugates synthesized was significantly more immunogenic than Vi alone. Recently, two Vi-tetanus toxoid conjugates were licensed in India for all ages, starts as young as 3 month old. This new generation of typhoid vaccine opens up a new era for typhoid prevention and elimination.

  1. Chiral amides via copper-catalysed enantioselective conjugate addition

    NARCIS (Netherlands)

    Schoonen, Anne K.; Fernández-Ibáñez, M. Ángeles; Fañanás-Mastral, Martín; Teichert, Johannes F.; Feringa, Bernard

    2014-01-01

    A highly enantioselective one pot procedure for the synthesis of β-substituted amides was developed starting from the corresponding α,β-unsaturated esters. This new methodology is based on the copper-catalysed enantioselective conjugate addition of Grignard reagents to α,β-unsaturated esters and sub

  2. Novel Bipolar Conjugated Polymer Containing Both Triphenylamine and Oxadizole Units

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel bipolar conjugated polymer containing triphenylamine and 1, 3, 4-oxadiazole units was synthesized by Suzuki reaction. Its structure and properties were characterized by NMR, IR, UV-Vis, PL spectroscopy and electrochemical measurement. The photoluminescent spectroscopy and cyclic voltammograms measurement demonstrated that the resulting polymer shows blue emission (477 nm) and possesses both electron and hole-transporting property.

  3. Facile Synthesis of Chiral Conjugated Polymer Based on BINOL Skeleton

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new type of chiral conjugated polymers 6a-d has been synthesized by the reaction of (R)-2,2'-dihydroxy-1,1'-binaphthyl-6,6'-dicarbaldehyde 5 with corresponding diamine in the presence of acetic acid.

  4. Patterning of conjugated polymers for organic optoelectronic devices.

    Science.gov (United States)

    Xu, Youyong; Zhang, Fan; Feng, Xinliang

    2011-05-23

    Conjugated polymers have been attracting more and more attention because they possess various novel electrical, magnetical, and optical properties, which render them useful in modern organic optoelectronic devices. Due to their organic nature, conjugated polymers are light-weight and can be fabricated into flexible appliances. Significant research efforts have been devoted to developing new organic materials to make them competitive with their conventional inorganic counterparts. It is foreseeable that when large-scale industrial manufacture of the devices made from organic conjugated polymers is feasible, they would be much cheaper and have more functions. On one hand, in order to improve the performance of organic optoelectronic devices, it is essential to tune their surface morphologies by techniques such as patterning. On the other hand, patterning is the routine requirement for device processing. In this review, the recent progress in the patterning of conjugated polymers for high-performance optoelectronic devices is summarized. Patterning based on the bottom-up and top-down methods are introduced. Emerging new patterning strategies and future trends for conventional patterning techniques are discussed.

  5. Opto-Electronic Properties of Conjugated Molecular Wires

    NARCIS (Netherlands)

    Grozema, F.C.

    2003-01-01

    Conjugated polymers are of considerable current interest because of their semi-conducting and light-emitting properties. These properties, combined with their relatively low cost and good processability as compared to inorganic semiconductors, make them attractive candidates for application in plast

  6. Diazobenzene-containing conjugated polymers as dark quenchers.

    Science.gov (United States)

    Wu, Jiatao; Tan, Ying; Xie, Yonghua; Wu, Yi; Zhao, Rui; Jiang, Yuyang; Tan, Chunyan

    2013-12-18

    The synthesis and photophysical characterization of new conjugated polymers (CPs) with alternating phenylethynylene and diazobenzene (azo-PPE) units were reported, which showed broadened absorption and no measurable fluorescence. Quenching studies showed that azo-PPEs displayed high efficiency over a wide wavelength range.

  7. Direct measurement of the microscale conductivity of conjugated polymer monolayers

    DEFF Research Database (Denmark)

    Bøggild, Peter; Grey, Francois; Hassenkam, T.;

    2000-01-01

    The in-plane conductivity of conjugated polymer monolayers is mapped here for the first time on the microscale using a novel scanning micro four-point probe (see Figure). The probe allows the source, drain, and voltage electrodes to be positioned within the same domain and the mapping results...... demonstrate how microscopic ordering in the polymer domains controls the conductivity....

  8. Tumor targeting of HPMA copolymer conjugates containing sulfadiazine groups

    Institute of Scientific and Technical Information of China (English)

    Jian Chao Yuan; Xiao Li Xie; Xian Wu Zeng; Hong Yun Guo; Cheng Ping Miao

    2012-01-01

    To develop new tumor targeting macromolecular conjugates,poly(HPMA)-SD-APMA-DTPA (HPMA:N-(2-hydroxypropyl)-methacrylamide; APMA:N-(3-aminopropyl)methacrylamide; DTPA:diethylenetriarninepentaacetic acid; SD:sulfadiazine) was synthesized and characterized.The poly(HPMA)-SD-DTPA conjugates were radiolabeled with the radionuclide 99mTc and tested for uptake by cultured H22 cells in vitro.DTPA-99mTc (radiotracer 1) and poly(HPMA)-DTPA-99mTc (radiotracer 2) were also synthesized and characterized for comparison.The uptake of poly(HPMA)-SD-DTPA-99mTc (radiotracer 3,34.76%) was significantly higher than that of poly(HPMA)-DTPA-99mTc (16.40%),indicating that uptake of the poly(HPMA)-SD-DTPA-99mT was active binding.The uptake of poly(HPMA)-DTPA-99mTc was significantly higher than that of DTPA-99mTc (2.98%),suggesting that uptake of the poly(HPMA)-DTPA-99mT was passive binding.The data suggest thin the poly(HPMA)-SD-APMA-DTPA conjugates might be useful as tumor targeting macromolecular conjugates.

  9. From Support to Control: A Configurational Perspective on Conjugal Quality

    Science.gov (United States)

    Widmer, Eric D.; Giudici, Francesco; Le Goff, Jean-Marie; Pollien, Alexandre

    2009-01-01

    The topic of conjugal quality provides an empirical illustration of the relevance of the configurational perspective on families. On the basis of a longitudinal sample of 1,534 couples living in Switzerland drawn from the study "Social Stratification, Cohesion and Conflict in Contemporary Families," we show that various types of interdependencies…

  10. Self-assembly behaviour of conjugated terthiophene surfactants in water

    NARCIS (Netherlands)

    van Rijn, Patrick; Janeliunas, Dainius; Brizard, Aurelie M.; Stuart, Marc C. A.; Koper, Ger J. M.; Eelkema, Rienk; van Esch, Jan H.

    2011-01-01

    Conjugated self-assembled systems in water are of great interest because of their potential application in biocompatible supramolecular electronics, but so far their supramolecular chemistry remains almost unexplored. Here we present amphiphilic terthiophenes as a general self-assembling platform fo

  11. Implementing the conjugate gradient algorithm on multi-core systems

    NARCIS (Netherlands)

    Wiggers, W.A.; Bakker, V.; Kokkeler, A.B.J.; Smit, G.J.M.; Nurmi, J.; Takala, J.; Vainio, O.

    2007-01-01

    In linear solvers, like the conjugate gradient algorithm, sparse-matrix vector multiplication is an important kernel. Due to the sparseness of the matrices, the solver runs relatively slow. For digital optical tomography (DOT), a large set of linear equations have to be solved which currently takes

  12. Antiobesity mechanisms of action of conjugated linoleic acid

    DEFF Research Database (Denmark)

    Kennedy, Arion; Martinez, Kristina; Schmidt, Soren;

    2010-01-01

    Conjugated linoleic acid (CLA), a family of fatty acids found in beef, dairy foods and dietary supplements, reduces adiposity in several animal models of obesity and some human studies. However, the isomer-specific antiobesity mechanisms of action of CLA are unclear, and its use in humans is...

  13. Programmable multimetallic linear nanoassemblies of ruthenium-DNA conjugates

    OpenAIRE

    Irvoas, Joris; Noirot, Arielle; Chouini-Lalanne, Nadia; Reynes, Olivier; Garrigues, Jean-Christophe; Sartor, Valérie

    2012-01-01

    International audience A new ruthenium-DNA conjugates family was synthesized, made up of a ruthenium complex bound to one or two identical DNA strands of 14-58 nucleotides. The formation of controlled linear nanoassemblies containing one to seven ruthenium complexes is described.

  14. Polyphenol-chitosan conjugates: Synthesis, characterization, and applications.

    Science.gov (United States)

    Hu, Qiaobin; Luo, Yangchao

    2016-10-20

    Chitosan, the only positively charged polysaccharide in the world, is very attractive for food, medicinal and pharmaceutical applications because of its promising properties, including non-toxicity, superb biodegradability, high biocompatibility, abundant availability and low cost. In order to overcome the poor water solubility and widen the applications of chitosan, various polyphenol-chitosan conjugates have been synthesized in recent years. The present review focuses on the chitosan-based conjugates formed using different polyphenols, including gallic acid, caffeic acid, ferulic acid, salicylic acid, catechin, and EGGE, etc. Three major synthesis techniques, namely, activated ester-mediated modification, enzyme-mediated strategy, and free radical induced grafting approach are introduced in detail. In addition, the new physicochemical and biological properties of polyphenol-chitosan conjugates are introduced, including water solubility, thermo stability, in vitro and in vivo antioxidant activity, antimicrobial and anticancer activity. Furthermore, the novel applications of each conjugate are discussed in detail. Lastly, the challenges and prospective areas of study related to polyphenol-chitosan are summarized. PMID:27474608

  15. Conjugal gene transfer between bacteria in soil and rhizosphere.

    NARCIS (Netherlands)

    Smit, E.

    1994-01-01

    The extent of possible conjugal transfer of recombinant DNA present in genetically engineered microorganisms (GEMs) was studied. Occurrence of transfer of recombinant DNA is only one of the concerns regarding the use of GEMs (Chapter 2). Other potential hazards preventing the application of GEMs for

  16. A Facile Synthesis of Indole-based Conjugated Derivatives

    Institute of Scientific and Technical Information of China (English)

    LI, Qian-Qian; ZHU, Zhi-Chao; LI,Zhen; QIN, Jin-Gui

    2007-01-01

    A novel synthetic method was developed for the preparation of indole-based conjugated derivatives with satisfied yields. By applying this strategy, a series of new compounds were prepared conveniently. All the obtained new indole derivatives were characterized by spectroscopic analyse s, giving satisfactory data corresponding to their expected molecular structures.

  17. Risk of Guillain-Barre syndrome after meningococcal conjugate vaccination

    NARCIS (Netherlands)

    Velentgas, P.; Amato, A.A.; Bohn, R.L.; Arnold Chan, K.; Cochrane, T.; Funch, D.P.; Dashevsky, I.; Duddy, A.L.; Gladowski, P.; Greenberg, S.A.; Kramer, J.M.; McMahill-Walraven, C.; Nakasato, C.; Spettell, C.M.; Syat, B.L.; Wahl, P.M.; Walker, A.M.; Zhang, F.; Brown, J.S.; Platt, R.

    2012-01-01

    PURPOSE: A new meningococcal conjugate vaccine (MCV4) was introduced in 2005. Shortly after, case reports of Guillain-Barre syndrome (GBS), a serious demyelinating disease, began to be reported to the Vaccine Adverse Event Reporting System. In 2006, the Centers for Disease Control and Prevention and

  18. A little less conjugation, a little more accuracy

    Science.gov (United States)

    2016-02-01

    The modification of proteins with fluorophores, drugs and polymers is required for many applications, yet conjugation reactions often generate a heterogeneous mixture of products. A collection of articles in this issue focuses on methods to modify proteins in a site-selective manner.

  19. Excitons in conjugated polymers: Do we need a paradigma change?

    Energy Technology Data Exchange (ETDEWEB)

    Beenken, Wichard J.D. [Department of Theoretical Physics I, Ilmenau University of Thechnology (Germany)

    2009-12-15

    We have previously shown that both, polymer conformation and dynamics are crucial for the exciton transport in conjugated polymers. Thereby we found that the usual Foerster-type hopping transfer model - even if one applies the line-dipole approximation - falls short in one crucial aspect: the nature of the sites the excitons are transferred between is still unclear. We found that the simple model of spectroscopic units defined as segments of the polymer chains separated by structural defects breaking the {pi}-conjugation is only justified for chemical defects like hydrogenated double bonds, or extreme gauche (90 ) torsions between the monomers. Both defects are far too rare in a well-prepared conjugated polymer to explain the mean spectroscopic-unit length of typically 6-7 monomers. Meanwhile, also the concept of dynamical formation of the spectroscopic units, we had previously suggested, has also failed. Thus the question of a paradigma change concerning the exciton transport in conjugated polymers appears on the agenda. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  20. Antibiotics as a selective driver for conjugation dynamics.

    Science.gov (United States)

    Lopatkin, Allison J; Huang, Shuqiang; Smith, Robert P; Srimani, Jaydeep K; Sysoeva, Tatyana A; Bewick, Sharon; Karig, David K; You, Lingchong

    2016-01-01

    It is generally assumed that antibiotics can promote horizontal gene transfer. However, because of a variety of confounding factors that complicate the interpretation of previous studies, the mechanisms by which antibiotics modulate horizontal gene transfer remain poorly understood. In particular, it is unclear whether antibiotics directly regulate the efficiency of horizontal gene transfer, serve as a selection force to modulate population dynamics after such gene transfer has occurred, or both. Here, we address this question by quantifying conjugation dynamics in the presence and absence of antibiotic-mediated selection. Surprisingly, we find that sublethal concentrations of antibiotics from the most widely used classes do not significantly increase the conjugation efficiency. Instead, our modelling and experimental results demonstrate that conjugation dynamics are dictated by antibiotic-mediated selection, which can both promote and suppress conjugation dynamics. Our findings suggest that the contribution of antibiotics to the promotion of horizontal gene transfer may have been overestimated. These findings have implications for designing effective antibiotic treatment protocols and for assessing the risks of antibiotic use. PMID:27572835

  1. Conjugation Properties of Tensor Product and Fusion Coefficients

    CERN Document Server

    Coquereaux, Robert

    2016-01-01

    We review some recent results on properties of tensor product and fusion coefficients under complex conjugation of one of the factors. Some of these results have been proven, some others are conjectures awaiting a proof, one of them involving hitherto unnoticed observations on ordinary representation theory of finite simple groups of Lie type

  2. Development and application of nanoparticles synthesized with folic acid-conjugated soy protein

    Science.gov (United States)

    In this study, soy protein isolate (SPI) was conjugated with folic acid (FA) to prepare nanoparticles for target-specific drug delivery. Successful conjugation was evidenced by UV spectrophotometry and primary amino group analysis. An increase in count rate by at least 142% was observed in FA-conjug...

  3. NHS Mediated CdTe Quantum Dots/Albumin Conjugates and Labeling C. Elegans

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Luminescent quantum dots(QDs) are a promising alternative to organic dyes for biomedical assays and imaging.A new conjugation method, NHS mediated conjugating, for QDs and BSA was introduced. The QDs-BSA conjugates were confirmed, and their stability has been proved. Caenorhabditis elegans (C. elegans) were used as animal models, and the imaging of QDs in the organism was studied.

  4. Synthesis and Cytotoxicity of Derivatives of Fluorouracil Conjugated with Three-membered Ring

    Institute of Scientific and Technical Information of China (English)

    WANG, Le; ZHANG, Yunxiao; TAO, Jingchao

    2009-01-01

    A novel series of 3-membered ring fluorouracil conjugates including cyclopropylmethyl fluorouracil and (2,3- epoxypropyl) fluorouracil conjugates were synthesized via selective protection, and their structures were confirmed by IR, 1H NMR and HRMS. Cytotoxicities in vitro of these conjugates were evaluated. Compounds 7, 8, 12 and 13 have shown cytotoxicities against Ec9706 cells in different degrees.

  5. CRITERION FOR SL(2,Z)-MATRIX TO BE CONJUGATE TO ITS INVERSE

    Institute of Scientific and Technical Information of China (English)

    龙以明

    2002-01-01

    This paper gives a necessary and sufficient condition for a matrix in SL(2, Z) to be conjugate to its inverse. This condition reduces the determination of the conjugation to solving some indeterminate equation of second degree. It yields an algorithm to determine this conjugation in finite steps based on the elementary number theory.

  6. Catalytic production of conjugated fatty acids and oils.

    Science.gov (United States)

    Philippaerts, An; Goossens, Steven; Jacobs, Pierre A; Sels, Bert F

    2011-06-20

    The reactive double bonds in conjugated vegetable oils are of high interest in industry. Traditionally, conjugated vegetable oils are added to paints, varnishes, and inks to improve their drying properties, while recently there is an increased interest in their use in the production of bioplastics. Besides the industrial applications, also food manufactures are interested in conjugated vegetable oils due to their various positive health effects. While the isomer type is less important for their industrial purposes, the beneficial health effects are mainly associated with the c9,t11, t10,c12 and t9,t11 CLA isomers. The production of CLA-enriched oils as additives in functional foods thus requires a high CLA isomer selectivity. Currently, CLAs are produced by conjugation of oils high in linoleic acid, for example soybean and safflower oil, using homogeneous bases. Although high CLA productivities and very high isomer selectivities are obtained, this process faces many ecological drawbacks. Moreover, CLA-enriched oils can not be produced directly with the homogeneous bases. Literature reports describe many catalytic processes to conjugate linoleic acid, linoleic acid methyl ester, and vegetable oils rich in linoleic acid: biocatalysts, for example enzymes and cells; metal catalysts, for example homogeneous metal complexes and heterogeneous catalysts; and photocatalysts. This Review discusses state-of-the-art catalytic processes in comparison with some new catalytic production routes. For each category of catalytic process, the CLA productivities and the CLA isomer selectivity are compared. Heterogeneous catalysis seems the most attractive approach for CLA production due to its easy recovery process, provided that the competing hydrogenation reaction is limited and the CLA production rate competes with the current homogeneous base catalysis. The most important criteria to obtain high CLA productivity and isomer selectivity are (1) absence of a hydrogen donor, (2

  7. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Science.gov (United States)

    Prati, Federica; Goldman-Pinkovich, Adele; Lizzi, Federica; Belluti, Federica; Koren, Roni; Zilberstein, Dan; Bolognesi, Maria Laura

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes) and intracellular (amastigotes) forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively). Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives. PMID:25254495

  8. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Directory of Open Access Journals (Sweden)

    Federica Prati

    Full Text Available The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7 to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III with amino acids (i.e. arginine and lysine by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes and intracellular (amastigotes forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively. Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives.

  9. Site-specific gene modification by PNAs conjugated to psoralen.

    Science.gov (United States)

    Kim, Ki-Hyun; Nielsen, Peter E; Glazer, Peter M

    2006-01-10

    DNA-binding molecules, including triplex-forming oligonucleotides (TFOs) and peptide nucleic acids (PNAs), can be utilized to introduce site-specific mutations or to promote recombination at selected genomic sites. To further evaluate the utility of PNAs for site-specific gene modification, we tested dimeric bis-PNAs conjugated to psoralen. These PNAs are designed to form a triplex-invasion complex within the supF reporter gene in an episomal shuttle vector and to direct site-specific photoadduct formation by the conjugated psoralen. The psoralen-bis-PNA conjugate was found to direct photoadduct formation to the intended 5'-TpA base step next to the PNA-binding site, and the photoadduct formation efficiency displayed both concentration and UVA irradiation dependence. The effect of PNA-targeted photoadducts in a mammalian system was tested by SV40-based shuttle vector assay. After in vitro binding, we found that photoadducts directed by PNAs conjugated to psoralen-induced mutations at frequencies in the range of 0.46%, 6.5-fold above the background. In a protocol for intracellular gene targeting in the episomal shuttle vector, the psoralen-PNA-induced mutation frequency was 0.13%, 3.5-fold higher than the background. Most of the induced mutations were deletions and single-base-pair substitutions at or adjacent to the targeted PNA-binding and photoadduct-formation sites. When the results are taken together, they demonstrate the ability of bis-PNAs conjugated with psoralen to mediate site-specific gene modification, and they further support the development of PNAs as tools for gene-targeting applications. PMID:16388608

  10. Synthesis, characterization and in vitro studies of pegylated melphalan conjugates.

    Science.gov (United States)

    Ajazuddin; Alexander, Amit; Amarji, Basant; Kanaujia, Parijat

    2013-07-01

    Melphalan, a drug used for the treatment of breast, ovaries and a certain type of cancer in the bone marrow, was conjugated to linear methoxy poly (ethylene glycol) (M-PEG) of 2000 and 5000, Da. An ester linkage between polymer and drug was used in the coupling to yield a polymeric prodrug. Purified esters were characterized by Maldi-Tof and IR spectroscopy methods. The modification allowed overcoming the known melphalan aqueous solubility problem (0.1 µg/ml) leading us to obtain a polymer-drug bioconjugate more suitable for oral and parental administration. It was found that molecular weight of M-PEG is critical for the conjugates stability, aqueous solubility (80 times and 123 times higher aqueous solubility for M-PEG 2000 and M-PEG 5000, respectively), and hemolytic activity. The melphalan caused 100% hemolysis above the concentration 3.5 µg/ml in 1 h. whereas conjugate of M-PEG 2000 and M-PEG 5000 shows 81.3 ± 0.5% and 48.8 ± 1.5% hemolysis, respectively at 32 µg/ml after1 h. Further In vitro anticancer activity of melphalan and its conjugates was performed with breast cancer MCF-7 cell lines. It shows that LD50 concentration was higher 1.14 and 2 µm for M-PEG 2000 and M-PEG 5000, respectively in comparison to pure melphalan (0.74 µm). Above studies revealed improved pharmacokinetics properties upon conjugation. PMID:22779444

  11. A conserved helicase processivity factor is needed for conjugation and replication of an integrative and conjugative element.

    Directory of Open Access Journals (Sweden)

    Jacob Thomas

    Full Text Available Integrative and conjugative elements (ICEs are agents of horizontal gene transfer and have major roles in evolution and acquisition of new traits, including antibiotic resistances. ICEs are found integrated in a host chromosome and can excise and transfer to recipient bacteria via conjugation. Conjugation involves nicking of the ICE origin of transfer (oriT by the ICE-encoded relaxase and transfer of the nicked single strand of ICE DNA. For ICEBs1 of Bacillus subtilis, nicking of oriT by the ICEBs1 relaxase NicK also initiates rolling circle replication. This autonomous replication of ICEBs1 is critical for stability of the excised element in growing cells. We found a conserved and previously uncharacterized ICE gene that is required for conjugation and replication of ICEBs1. Our results indicate that this gene, helP (formerly ydcP, encodes a helicase processivity factor that enables the host-encoded helicase PcrA to unwind the double-stranded ICEBs1 DNA. HelP was required for both conjugation and replication of ICEBs1, and HelP and NicK were the only ICEBs1 proteins needed for replication from ICEBs1 oriT. Using chromatin immunoprecipitation, we measured association of HelP, NicK, PcrA, and the host-encoded single-strand DNA binding protein Ssb with ICEBs1. We found that NicK was required for association of HelP and PcrA with ICEBs1 DNA. HelP was required for association of PcrA and Ssb with ICEBs1 regions distal, but not proximal, to oriT, indicating that PcrA needs HelP to progress beyond nicked oriT and unwind ICEBs1. In vitro, HelP directly stimulated the helicase activity of the PcrA homologue UvrD. Our findings demonstrate that HelP is a helicase processivity factor needed for efficient unwinding of ICEBs1 for conjugation and replication. Homologues of HelP and PcrA-type helicases are encoded on many known and putative ICEs. We propose that these factors are essential for ICE conjugation, replication, and genetic stability.

  12. A conserved helicase processivity factor is needed for conjugation and replication of an integrative and conjugative element.

    Science.gov (United States)

    Thomas, Jacob; Lee, Catherine A; Grossman, Alan D

    2013-01-01

    Integrative and conjugative elements (ICEs) are agents of horizontal gene transfer and have major roles in evolution and acquisition of new traits, including antibiotic resistances. ICEs are found integrated in a host chromosome and can excise and transfer to recipient bacteria via conjugation. Conjugation involves nicking of the ICE origin of transfer (oriT) by the ICE-encoded relaxase and transfer of the nicked single strand of ICE DNA. For ICEBs1 of Bacillus subtilis, nicking of oriT by the ICEBs1 relaxase NicK also initiates rolling circle replication. This autonomous replication of ICEBs1 is critical for stability of the excised element in growing cells. We found a conserved and previously uncharacterized ICE gene that is required for conjugation and replication of ICEBs1. Our results indicate that this gene, helP (formerly ydcP), encodes a helicase processivity factor that enables the host-encoded helicase PcrA to unwind the double-stranded ICEBs1 DNA. HelP was required for both conjugation and replication of ICEBs1, and HelP and NicK were the only ICEBs1 proteins needed for replication from ICEBs1 oriT. Using chromatin immunoprecipitation, we measured association of HelP, NicK, PcrA, and the host-encoded single-strand DNA binding protein Ssb with ICEBs1. We found that NicK was required for association of HelP and PcrA with ICEBs1 DNA. HelP was required for association of PcrA and Ssb with ICEBs1 regions distal, but not proximal, to oriT, indicating that PcrA needs HelP to progress beyond nicked oriT and unwind ICEBs1. In vitro, HelP directly stimulated the helicase activity of the PcrA homologue UvrD. Our findings demonstrate that HelP is a helicase processivity factor needed for efficient unwinding of ICEBs1 for conjugation and replication. Homologues of HelP and PcrA-type helicases are encoded on many known and putative ICEs. We propose that these factors are essential for ICE conjugation, replication, and genetic stability. PMID:23326247

  13. Digital phase conjugate mirror by parallel arrangement of two phase-only spatial light modulators.

    Science.gov (United States)

    Shibukawa, Atsushi; Okamoto, Atsushi; Goto, Yuta; Honma, Satoshi; Tomita, Akihisa

    2014-05-19

    In a conventional digital phase conjugation system, only the phase of an input light is time-reversed. This deteriorates phase conjugation fidelity and restricts application fields to specific cases only when the input light has uniformly-distributed scattered wavefront. To overcome these difficulties, we present a digital phase conjugate mirror based on parallel alignment of two phase-only spatial light modulators (SLMs), in which both amplitude and phase of the input light can be time-reversed. Experimental result showed that, in the phase conjugation through a holographic diffuser with diffusion angle of 0.5 degree, background noises decrease to 65% by our digital phase conjugation mirror.

  14. The stb operon balances the requirements for vegetative stability and conjugative transfer of plasmid R388

    OpenAIRE

    Catherine Guynet; Ana Cuevas; Gabriel Moncalián; Fernando de la Cruz

    2011-01-01

    The conjugative plasmid R388 and a number of other plasmids carry an operon, stbABC, adjacent to the origin of conjugative transfer. We investigated the role of the stbA, stbB, and stbC genes. Deletion of stbA affected both conjugation and stability. It led to a 50-fold increase in R388 transfer frequency, as well as to high plasmid loss. In contrast, deletion of stbB abolished conjugation but provoked no change in plasmid stability. Deletion of stbC showed no effect, neither in conjugation n...

  15. Axial range of conjugate adaptive optics in two-photon microscopy

    CERN Document Server

    Paudel, Hari P; Mertz, Jerome; Bifano, Thomas

    2015-01-01

    We describe an adaptive optics technique for two-photon microscopy in which the deformable mirror used for aberration compensation is positioned in a plane conjugate to the plane of the aberration. We demonstrate in a proof-of-principle experiment that this technique yields a large field of view advantage in comparison to standard pupil-conjugate adaptive optics. Further, we show that the extended field of view in conjugate AO is maintained over a relatively large axial translation of the deformable mirror with respect to the conjugate plane. We conclude with a discussion of limitations and prospects for the conjugate AO technique in two-photon biological microscopy.

  16. Nanohybrid conjugated polyelectrolytes: highly photostable and ultrabright nanoparticles

    Science.gov (United States)

    Darwish, Ghinwa H.; Karam, Pierre

    2015-09-01

    We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (~109, on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the conjugated polyelectrolyte from the destructive photooxidation. The prepared nanohybrid particles will prove instrumental in single particle based fluorescent assays and can serve as a probe for the current state-of-the-art bioimaging fluorescence techniques.We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (~109, on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the

  17. A comparison of chemiluminescent acridinium dimethylphenyl ester labels with different conjugation sites.

    Science.gov (United States)

    Natrajan, Anand; Wen, David

    2015-03-01

    Chemiluminescent acridinium dimethylphenyl esters are highly sensitive labels that are used in automated assays for clinical diagnosis. Light emission from these labels and their conjugates is triggered by treatment with alkaline peroxide. Conjugation of acridinium ester labels is normally done at the phenol. During the chemiluminescent reaction of these acridinium esters, the phenolic ester is cleaved and the light emitting acridone moiety is liberated from its conjugate partner. In the current study, we report the synthesis of three new acridinium esters with conjugation sites at the acridinium nitrogen and compare their properties with that of a conventional acridinium ester with a conjugation site at the phenol. Our study is the first that provides a direct comparison of the emissive properties of acridinium dimethylphenyl esters (free labels and protein conjugates) with different conjugation sites, one where the light emitting acridone remains attached to its conjugate partner versus conventional labeling which results in cleavage of the acridone from the conjugate. Our results indicate that the conjugation at the acridinium nitrogen, which also alters how the acridinium ring and phenol are oriented with respect to the protein surface, has a minimal impact on emission kinetics and emission spectra. However, this mode of conjugation to three different proteins led to a significant increase in light yield which should be useful for improving the assay sensitivity. PMID:25581208

  18. Current preclinical small interfering RNA (siRNA)-based conjugate systems for RNA therapeutics.

    Science.gov (United States)

    Lee, Soo Hyeon; Kang, Yoon Young; Jang, Hyo-Eun; Mok, Hyejung

    2016-09-01

    Recent promising clinical results of RNA therapeutics have drawn big attention of academia and industries to RNA therapeutics and their carrier systems. To improve their feasibility in clinics, systemic evaluations of currently available carrier systems under clinical trials and preclinical studies are needed. In this review, we focus on recent noticeable preclinical studies and clinical results regarding siRNA-based conjugates for clinical translations. Advantages and drawbacks of siRNA-based conjugates are discussed, compared to particle-based delivery systems. Then, representative siRNA-based conjugates with aptamers, peptides, carbohydrates, lipids, polymers, and nanostructured materials are introduced. To improve feasibility of siRNA conjugates in preclinical studies, several considerations for the rational design of siRNA conjugates in terms of cleavability, immune responses, multivalent conjugations, and mechanism of action are also presented. Lastly, we discuss lessons from previous preclinical and clinical studies related to siRNA conjugates and perspectives of their clinical applications. PMID:26514375

  19. HER2 specific delivery of methotrexate by dendrimer conjugated anti-HER2 mAb

    Science.gov (United States)

    Shukla, Rameshwer; Thomas, Thommey P.; Desai, Ankur M.; Kotlyar, Alina; Park, Steve J.; Baker, James R., Jr.

    2008-07-01

    Herceptin, a humanized monoclonal antibody that binds to human growth factor receptor-2 (HER2), was covalently attached to a fifth-generation (G5) polyamidoamine dendrimer containing the cytotoxic drug methotrexate. The specific binding and internalization of this conjugate labeled with FITC was clearly demonstrated in cell lines overexpressing HER2 by flow cytometry as well as confocal microscopic analysis. In addition, binding and uptake of antibody conjugated dendrimers was completely blocked by excess non-conjugated herceptin. The dendrimer conjugate was also shown to inhibit the dihydrofolate reductase with similar activity to methotrexate. Co-localization experiments with lysotracker red indicate that antibody conjugate, although internalized efficiently into cells, has an unusually long residence time in the lysosome. Somewhat lower cytotoxicity of the conjugate in comparison to free methotrexate was attributed to the slow release of methotrexate from the conjugate and its long retention in the lysosomal pocket.

  20. HER2 specific delivery of methotrexate by dendrimer conjugated anti-HER2 mAb

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Rameshwer; Thomas, Thommey P; Desai, Ankur M; Kotlyar, Alina; Park, Steve J; Baker, James R Jr [Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, 9220 MSRB III, Box 0648, Ann Arbor, MI 48109 (United States)], E-mail: rameshwe@umich.edu, E-mail: jbakerjr@med.umich.edu

    2008-07-23

    Herceptin, a humanized monoclonal antibody that binds to human growth factor receptor-2 (HER2), was covalently attached to a fifth-generation (G5) polyamidoamine dendrimer containing the cytotoxic drug methotrexate. The specific binding and internalization of this conjugate labeled with FITC was clearly demonstrated in cell lines overexpressing HER2 by flow cytometry as well as confocal microscopic analysis. In addition, binding and uptake of antibody conjugated dendrimers was completely blocked by excess non-conjugated herceptin. The dendrimer conjugate was also shown to inhibit the dihydrofolate reductase with similar activity to methotrexate. Co-localization experiments with lysotracker red indicate that antibody conjugate, although internalized efficiently into cells, has an unusually long residence time in the lysosome. Somewhat lower cytotoxicity of the conjugate in comparison to free methotrexate was attributed to the slow release of methotrexate from the conjugate and its long retention in the lysosomal pocket.

  1. HER2 specific delivery of methotrexate by dendrimer conjugated anti-HER2 mAb

    International Nuclear Information System (INIS)

    Herceptin, a humanized monoclonal antibody that binds to human growth factor receptor-2 (HER2), was covalently attached to a fifth-generation (G5) polyamidoamine dendrimer containing the cytotoxic drug methotrexate. The specific binding and internalization of this conjugate labeled with FITC was clearly demonstrated in cell lines overexpressing HER2 by flow cytometry as well as confocal microscopic analysis. In addition, binding and uptake of antibody conjugated dendrimers was completely blocked by excess non-conjugated herceptin. The dendrimer conjugate was also shown to inhibit the dihydrofolate reductase with similar activity to methotrexate. Co-localization experiments with lysotracker red indicate that antibody conjugate, although internalized efficiently into cells, has an unusually long residence time in the lysosome. Somewhat lower cytotoxicity of the conjugate in comparison to free methotrexate was attributed to the slow release of methotrexate from the conjugate and its long retention in the lysosomal pocket

  2. Phase conjugator with two coherent beams in a BaTiO3: Ce crystal

    Institute of Scientific and Technical Information of China (English)

    武建劳; 谢平; 戴建华; 张洪钧

    2000-01-01

    A phase conjugator which includes two coherent beams that are incident upon one of a-faces of a BaTiO3: Ce crystal without internal reflection is performed experimentally. Based on the four-wave mixing, the mechanism of this conjugator is investigated numerically. in comparison with the cor-responding self-pumped phase conjugator, the phase-conjugate behavior of this conjugator is estab-lished much more quickly, its phase conjugate reflectivity is greater in some cases and the intensity threshold is lower by over two orders of magnitude. The configuration of this conjugator is easy to per-form because the output response exists over a wide range of angular and lateral positions of the two incident beams on the crystal.

  3. Wavelet methods in multi-conjugate adaptive optics

    CERN Document Server

    Helin, Tapio

    2013-01-01

    The next generation ground-based telescopes rely heavily on adaptive optics for overcoming the limitation of atmospheric turbulence. In the future adaptive optics modalities, like multi-conjugate adaptive optics (MCAO), atmospheric tomography is the major mathematical and computational challenge. In this severely ill-posed problem a fast and stable reconstruction algorithm is needed that can take into account many real-life phenomena of telescope imaging. We introduce a novel reconstruction method for the atmospheric tomography problem and demonstrate its performance and flexibility in the context of MCAO. Our method is based on using locality properties of compactly supported wavelets, both in the spatial and frequency domain. The reconstruction in the atmospheric tomography problem is obtained by solving the Bayesian MAP estimator with a conjugate gradient based algorithm. An accelerated algorithm with preconditioning is also introduced. Numerical performance is demonstrated on the official end-to-end simul...

  4. Recent Advances in Boron-Containing Conjugated Porous Polymers

    Directory of Open Access Journals (Sweden)

    Feng Qiu

    2016-05-01

    Full Text Available Porous polymers, integrating the advantages of porous materials and conventional polymers, have been well developed and exhibited tremendous attention in the fields of material, chemistry and biology. Of these, boron-containing conjugated porous polymers, featuring tunable geometric structures, unique Lewis acid boron centers and very rich physical properties, such as high specific surface, chargeable scaffold, strong photoluminescence and intramolecular charge transfer, have emerged as one of the most promising functional materials for optoelectronics, catalysis and sensing, etc. Furthermore, upon thermal treatment, some of them can be effectively converted to boron-doped porous carbon materials with good electrochemical performance in energy storage and conversion, extensively enlarging the applicable scope of such kinds of polymers. In this review, the synthetic approaches, structure analyses and various applications of the boron-containing conjugated porous polymers reported very recently are summarized.

  5. All solid-state SBS phase conjugate mirror

    Science.gov (United States)

    Dane, C.B.; Hackel, L.A.

    1999-03-09

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  6. Wavelet methods in multi-conjugate adaptive optics

    Science.gov (United States)

    Helin, T.; Yudytskiy, M.

    2013-08-01

    The next generation ground-based telescopes rely heavily on adaptive optics for overcoming the limitation of atmospheric turbulence. In the future adaptive optics modalities, like multi-conjugate adaptive optics (MCAO), atmospheric tomography is the major mathematical and computational challenge. In this severely ill-posed problem, a fast and stable reconstruction algorithm is needed that can take into account many real-life phenomena of telescope imaging. We introduce a novel reconstruction method for the atmospheric tomography problem and demonstrate its performance and flexibility in the context of MCAO. Our method is based on using locality properties of compactly supported wavelets, both in the spatial and frequency domains. The reconstruction in the atmospheric tomography problem is obtained by solving the Bayesian MAP estimator with a conjugate-gradient-based algorithm. An accelerated algorithm with preconditioning is also introduced. Numerical performance is demonstrated on the official end-to-end simulation tool OCTOPUS of European Southern Observatory.

  7. Design and synthesis of isosteviol triazole conjugates for cancer therapy.

    Science.gov (United States)

    Khaybullin, Ravil N; Zhang, Mei; Fu, Junjie; Liang, Xiao; Li, Tammy; Katritzky, Alan R; Okunieff, Paul; Qi, Xin

    2014-01-01

    One of the keys for successfully developing drugs against the broad spectrum of cancer cell types is structural diversity. In the current study, we focused on a family of isosteviol derivatives as potential novel antitumor agents. Isosteviol is a tetracyclic diterpenoid obtained by acid hydrolysis of steviol glycoside extracts isolated from abundant Stevia rebaudiana plants. In this work, we have designed and synthesized a panel of isosteviol triazole conjugates using "click" chemistry methodology. Evaluation of these compounds against a series of cancer cell lines derived from primary and metastatic tumors demonstrated that these conjugates exhibit cytotoxic activities with IC50 in the low μM range. In addition, their anti-proliferative activities are cancer cell type specific. Taken together, our studies underscore the importance of structural diversity in achieving cancer cell type specific drug development. PMID:25405286

  8. Design and Synthesis of Isosteviol Triazole Conjugates for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Ravil N. Khaybullin

    2014-11-01

    Full Text Available One of the keys for successfully developing drugs against the broad spectrum of cancer cell types is structural diversity. In the current study, we focused on a family of isosteviol derivatives as potential novel antitumor agents. Isosteviol is a tetracyclic diterpenoid obtained by acid hydrolysis of steviol glycoside extracts isolated from abundant Stevia rebaudiana plants. In this work, we have designed and synthesized a panel of isosteviol triazole conjugates using “click” chemistry methodology. Evaluation of these compounds against a series of cancer cell lines derived from primary and metastatic tumors demonstrated that these conjugates exhibit cytotoxic activities with IC50 in the low μM range. In addition, their anti-proliferative activities are cancer cell type specific. Taken together, our studies underscore the importance of structural diversity in achieving cancer cell type specific drug development.

  9. Quantum dot conjugates in a sub-micrometer fluidic channel

    Science.gov (United States)

    Stavis, Samuel M.; Edel, Joshua B.; Samiee, Kevan T.; Craighead, Harold G.

    2010-04-13

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  10. Coherent chirped pulse laser network with Mickelson phase-conjugator

    CERN Document Server

    Okulov, A Yu

    2013-01-01

    The mechanisms of nonlinear phase-locking of a large fiber amplifier array are analyzed. The preference is given to configuration most suitable for a coherent coupling of a thousands of a fundamental spatial mode fiber beams into a single smooth beam ready for chirped pulse compression. It is shown that Michelson phase conjugating configuration with double passage through array of fiber amplifiers have the definite advantages compared to one-way fiber array coupled in a Mach-Zehnder configuration. Regardless to amount of synchronized fiber amplifiers Michelson phase-conjugating interferometer is expected to do a perfect compensation of the phase-piston errors and collimation of backwardly amplified fiber beams on entrance/output beamsplitter. In both configurations the nonlinear transformation of the stretched pulse envelope due to gain saturation is capable to randomize the position of chirp inside envelope thus it may reduce the visibility of interference pattern at output beamsplitter. A certain advantages...

  11. Conjugated polymer fluorescence: Interplay of correlations and alternation

    Energy Technology Data Exchange (ETDEWEB)

    Soos, Z.G. [Princeton Univ., NJ (United States). Dept. of Chemistry; Galvao, D.S. [Bell Communications Research, Inc., Red Bank, NJ (United States)]|[Universidade Estadual de Campinas, SP (Brazil). Dept. de Fisica Aplicada; Etemad, S. [Bell Communications Research, Inc., Red Bank, NJ (United States); Kepler, R.G. [Sandia National Labs., Albuquerque, NM (United States)

    1993-12-31

    Conjugated polymers can have high conductivity on doping, large nonlinear optical response in semiconducting state, and be used as LEDs. These polymers include polyactylene, polydiacetylenes, polysilanes, polythiophene, poly-p-phenylenevinylene. Polymer fluorescence is related to the lowest singlet excited state S{sub 1}. Polymer and oligomer data are shown for the excitation energy ratio of the two-photon and one-photon gaps. There is a ratio crossover with increasing e-e correlations in any centrosymmetri chain with an insulating ground state. The {pi}-conjugated polymers present various band gaps at constant correlations, and single-particle gaps can be related to the structure. The nature of the lowest singlet excited state depends sensitively on both correlations and alternation. 22 refs, 2 figs.

  12. Oligonucleotide Tagging for Copper-Free Click Conjugation

    Directory of Open Access Journals (Sweden)

    Alan Rowan

    2013-06-01

    Full Text Available Copper-free click chemistry between cyclooctynes and azide is a mild, fast and selective technology for conjugation of oligonucleotides. However, technology for site-specific introduction of the requisite probes by automated protocols is scarce, while the reported cyclooctynes are large and hydrophobic. In this work, it is demonstrated that the introduction of bicyclo[6.1.0]nonyne (BCN into synthetic oligonucleotides is feasible by standard solid-phase phosphoramidite chemistry. A range of phosphoramidite building blocks is presented for incoporation of BCN or azide, either on-support or in solution. The usefulness of the approach is demonstrated by the straightforward and high-yielding conjugation of the resulting oligonucleotides, including biotinylation, fluorescent labeling, dimerization and attachment to polymer.

  13. Detection of Lectins by Saccharide-gold Nanoparticle Conjugates

    Institute of Scientific and Technical Information of China (English)

    HOU Qiong; WANG Jin-e; LIU Xia; LI Xiao-kun; MA Li-na; DUAN Wu-biao; WANG Zhen-xin

    2012-01-01

    A general functionalization strategy was reported,which enables one to conjugate saccharide(SA) on gold nanoparticle(GNP) surface without affecting SA properties.First,disulfide phenylboronic acid(Bor) functionalized GNPs(Bor@GNPs) were synthesized by the reaction of citrate stabilized GNPs of 13 nm in diameter with the mixture of Bor and pentapeptide(Cys-Ala-Leu-Asn-Asn,CALNN).Subsequently,the SA-GNP conjugates(SA@GNPs) were prepared by coupling SA to the GNP surface via the reaction of phenylboronic acid(PBA) with the cis-diol configuration in SA.The interactions of three SA@GNPs with three lectins have been analyzed by UV-visible spectroscopic and transmission electronic microscopic(TEM) techniques,respectively.The experimental results demonstrate that SA@GNPs can efficiently bind to lectins and show a great promise as optical probes for monitoring specific affinities of lectins for SA,and detecting lectins with high sensitivity.

  14. Conjugated Molecules for the Smart Filtering of Intense Radiations

    Directory of Open Access Journals (Sweden)

    Danilo Dini

    2003-04-01

    Full Text Available Abstract: The practical realization of smart optical filters, i.e. devices which change their optical transmission in a suitable way to keep a working state for a general light sensitive element , can involve the use of conjugated molecules whose light absorption properties are light- intensity dependent (nonlinear optical effect. The verification of optical limiting displayed by some particular conjugated molecules, e.g. phthalocyanines, is quite noteworthy and can be successfully exploited for the realization of such smart optical devices. In the present contribution the analysis of the relevant molecular feature of a phthalocyanine are analyzed with the aim of determining useful correlations between optical limiting performance and phthalocyanine chemical structure. In particular , the electronic nature of the substituent is considered as a key factor for the explanation of some observed optical limiting trends.

  15. Helical peptide-polyamine and -polyether conjugates as synthetic ionophores.

    Science.gov (United States)

    Benincasa, Monica; Francescon, Marco; Fregonese, Massimo; Gennaro, Renato; Pengo, Paolo; Rossi, Paola; Scrimin, Paolo; Tecilla, Paolo

    2015-12-01

    Two new synthetic ionophores in which the hydrophobic portion is represented by a short helical Aib-peptide (Aib=α-amino-isobutyric acid) and the hydrophilic one is a poly-amino (1a) or a polyether (1b) chain have been prepared. The two conjugates show a high ionophoric activity in phospholipid membranes being able to efficiently dissipate a pH gradient and, in the case of 1b, to transport Na(+) across the membrane. Bioactivity evaluation of the two conjugates shows that 1a has a moderate antimicrobial activity against a broad spectrum of microorganisms and it is able to permeabilize the inner and the outer membrane of Escherichia coli cells. PMID:26558517

  16. Polythiophenes Comprising Conjugated Pendants for Polymer Solar Cells: A Review

    Directory of Open Access Journals (Sweden)

    Hsing-Ju Wang

    2014-03-01

    Full Text Available Polythiophene (PT is one of the widely used donor materials for solution-processable polymer solar cells (PSCs. Much progress in PT-based PSCs can be attributed to the design of novel PTs exhibiting intense and broad visible absorption with high charge carrier mobility to increase short-circuit current density (Jsc, along with low-lying highest occupied molecular orbital (HOMO levels to achieve large open circuit voltage (Voc values. A promising strategy to tailor the photophysical properties and energy levels via covalently attaching electron donor and acceptor pendants on PTs backbone has attracted much attention recently. The geometry, electron-donating capacity, and composition of conjugated pendants are supposed to be the crucial factors in adjusting the conformation, energy levels, and photovoltaic performance of PTs. This review will go over the most recent approaches that enable researchers to obtain in-depth information in the development of PTs comprising conjugated pendants for PSCs.

  17. Stereoselective sulphate conjugation of racemic terbutaline by human liver cytosol.

    Science.gov (United States)

    Walle, T; Walle, U K

    1990-07-01

    1. The enantioselectivity of the sulphation of racemic terbutaline by phenolsulphotransferases was examined in vitro using cytosol from human livers (n = 3) and [35S]-3'-phosphoadenosine-5'-phosphosulphate (PAP35S) as the sulphate donor. 2. The radioactive sulphate conjugate formed was isolated by h.p.l.c. and its enantiomers were separated intact by h.p.l.c. after chiral derivatization. 3. Sulphation of racemic terbutaline occurred with the same apparent Km value for both enantiomers (270 microM). The extent of sulphation of the (+)-enantiomer was double that of the (-)-enantiomer, solely due to a difference in their apparent Vmax values. 4. Sulphation of racemic prenalterol, a structural analogue of terbutaline, also showed a two-fold preference for the (+)-enantiomer. 5. These findings suggest that enantioselective sulphate conjugation of chiral phenolic sympathomimetic amine drugs may lead to enantioselective pharmacokinetics that should be considered in the clinical use of these drugs. PMID:2390423

  18. Application of Conjugate Gradient methods to tidal simulation

    Science.gov (United States)

    Barragy, E.; Carey, G.F.; Walters, R.A.

    1993-01-01

    A harmonic decomposition technique is applied to the shallow water equations to yield a complex, nonsymmetric, nonlinear, Helmholtz type problem for the sea surface and an accompanying complex, nonlinear diagonal problem for the velocities. The equation for the sea surface is linearized using successive approximation and then discretized with linear, triangular finite elements. The study focuses on applying iterative methods to solve the resulting complex linear systems. The comparative evaluation includes both standard iterative methods for the real subsystems and complex versions of the well known Bi-Conjugate Gradient and Bi-Conjugate Gradient Squared methods. Several Incomplete LU type preconditioners are discussed, and the effects of node ordering, rejection strategy, domain geometry and Coriolis parameter (affecting asymmetry) are investigated. Implementation details for the complex case are discussed. Performance studies are presented and comparisons made with a frontal solver. ?? 1993.

  19. Synthesis and anti-angiogenic effect of conjugates between serum albumin and non-steroidal anti-inflammatory drugs

    DEFF Research Database (Denmark)

    Kjaer, B; Struve, C; Friis, T;

    2010-01-01

    of investigating the anti-angiogenic efficiency of NSAID-HSA conjugates in vitro, three NSAIDs, aspirin, ibuprofen, and naproxen were conjugated to HSA using different concentrations of their N-hydroxysuccinimide esters. Conjugation ratios from 10 to 50 were achieved and the conjugates retained a growth inhibitory...

  20. Streptavidin conjugation and quantification-a method evaluation for nanoparticles.

    Science.gov (United States)

    Quevedo, Pablo Darío; Behnke, Thomas; Resch-Genger, Ute

    2016-06-01

    Aiming at the development of validated protocols for protein conjugation of nanomaterials and the determination of protein labeling densities, we systematically assessed the conjugation of the model protein streptavidin (SAv) to 100-, 500-, and 1000-nm-sized polystyrene and silica nanoparticles and dye-encoded polymer particles with two established conjugation chemistries, based upon achievable coupling efficiencies and labeling densities. Bioconjugation reactions compared included EDC/sulfo NHS ester chemistry for direct binding of the SAv to carboxyl groups at the particle surface and maleimide-thiol chemistry in conjunction with heterobifunctional PEG linkers and aminated nanoparticles (NPs). Quantification of the total and functional amounts of SAv on these nanomaterials and unreacted SAv in solution was performed with the BCA assay and the biotin-FITC (BF) titration, relying on different signal generation principles, which are thus prone to different interferences. Our results revealed a clear influence of the conjugation chemistry on the amount of NP crosslinking, yet under optimized reaction conditions, EDC/sulfo NHS ester chemistry and the attachment via heterobifunctional PEG linkers led to comparably efficient SAv coupling and good labeling densities. Particle size can obviously affect protein labeling densities and particularly protein functionality, especially for larger particles. For unstained nanoparticles, direct bioconjugation seems to be the most efficient strategy, whereas for dye-encoded nanoparticles, PEG linkers are to be favored for the prevention of dye-protein interactions which can affect protein functionality specifically in the case of direct SAv binding. Moreover, an influence of particle size on achievable protein labeling densities and protein functionality could be demonstrated. PMID:27038055

  1. Liposomes surface conjugated with human hemoglobin target delivery to macrophages

    OpenAIRE

    Zhang, Ning; Palmer, Andre F.

    2011-01-01

    Current strategies to deliver therapeutic molecules to specific cell and tissue types rely on conjugation of antibodies and other targeting ligands directly to the therapeutic molecule itself or its carrier. This work describes a novel strategy to deliver therapeutic molecules into macrophages that takes advantage of the native hemoglobin (Hb) scavenging activity of plasma haptoglobin (Hp) and the subsequent uptake of the Hb-Hp complex into macrophages via CD163 receptor mediated endocytosis....

  2. Stress Intensity of Antiplane Conjugate Cracks in Cubic Quasicrystal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei

    2008-01-01

    Based on the theory of Muskhelishvili, the general solutions for stress and strain of conjugate cracks in cubic quasicrystal are obtained, with which the stress intensity factors of cubic quasicrystal at crack tips and the stress distribution functions of phonon and phason fields are given. The results show that though phason field is coupled with phonon field by constitutive equations, the stress intensity factors are not coupled with any other factors.

  3. Controlled Self Assembly of Conjugated Polymer Containing Block Copolymers

    OpenAIRE

    McCulloch, Bryan

    2012-01-01

    The discovery and development of conjugated polymers has led to a large and vibrant research field due to their unique semiconducting properties and possibility of offering a completely new paradigm due to their abundant, lightweight, flexible and solution processable properties. In particular, the optoelectronic properties of these materials make them very well suited to applications such as organic light emitting diodes or organic photovoltaics and their relatively high charge mobility als...

  4. Efficacy and effectiveness of extended-valency pneumococcal conjugate vaccines

    OpenAIRE

    Lee, Hyunju; Choi, Eun Hwa; Lee, Hoan Jong

    2014-01-01

    The 7-valent pneumococcal protein conjugate vaccine (PCV7) has been shown to be highly efficacious against invasive pneumococcal diseases and effective against pneumonia and in reducing otitis media. The introduction of PCV7 has resulted in major changes in the epidemiology of pneumococcal diseases. However, pneumococcal vaccines induce serotype-specific immunity, and a relative increase in non-vaccine serotypes has been reported following the widespread use of PCV7, leading to a need for ext...

  5. Update on the success of the pneumococcal conjugate vaccine

    OpenAIRE

    Kellner, JD

    2011-01-01

    Several years after the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in Canada and elsewhere, routine infant vaccination has led to near eradication of invasive pneumococcal disease caused by vaccine serotype strains in both children and adults. There have also been significant declines in pneumococcal-related disease including lobar pneumonia and otitis media. These declines have been offset, to some extent, by increases in nonvaccine serotype disease. Serotype 19A, whic...

  6. Radiolabeled Cetuximab Conjugates for EGFR Targeted Cancer Diagnostics and Therapy

    OpenAIRE

    Wiebke Sihver; Jens Pietzsch; Mechthild Krause; Michael Baumann; Jörg Steinbach; Hans-Jürgen Pietzsch

    2014-01-01

    The epidermal growth factor receptor (EGFR) has evolved over years into a main molecular target for the treatment of different cancer entities. In this regard, the anti-EGFR antibody cetuximab has been approved alone or in combination with: (a) chemotherapy for treatment of colorectal and head and neck squamous cell carcinoma and (b) with external radiotherapy for treatment of head and neck squamous cell carcinoma. The conjugation of radionuclides to cetuximab in combination with the specif...

  7. Optical phase conjugation in semiconductor-doped glasses

    Science.gov (United States)

    Roussignol, P.; Ricard, D.; Rustagi, K. C.; Flytzanis, C.

    1985-08-01

    We have studied optical phase conjugation in two types of semiconductor-doped glasses. Corning 3.68 and Schott OG 530 at λ = 0.532 μm using picosecond pulses. We observe a slow nonlinearity in agreement with the slow decay of luminescence. The saturation of the reflectivity is strongly correlated with the absorption saturation of these glasses and may be interpreted in terms of a three-level system model.

  8. DNA-Conjugated Organic Chromophores in DNA Stacking Interactions

    DEFF Research Database (Denmark)

    Filichev, Vyacheslav V.; Pedersen, Erik Bjerregaard

    2009-01-01

    Since the discovery of the intercalation of acridine derivatives into DNA (1961), chemists have synthesized many intercalators tethered to DNA. Advances in the chemical synthesis of modified nucleosides along with progress in oligonucleotide synthesis have made it possible to introduce organic...... review presents those efforts in the design of intercalators/organic chromophores as oligonucleotide conjugates that form a foundation for the generation of novel nucleic acid architectures...

  9. A SMOOTHING CONJUGATE GRADIENT ALGORITHM FOR NONLINEAR COMPLEMENTARITY PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Caiying WU; Guoqing CHEN

    2008-01-01

    A PRP-type smoothing conjugate gradient method for solving large scale nonlinearcomplementarity problems (NCP( F )) is proposed. At each iteration, two Armijo line searches are performed, which guarantees the positive property of the smoothing parameter and minimizes the merit function formed by Fischer-Burmeister function, respectively. Global convergence is studied when F : Rn→Rn is a continuously differentiable P0 + R0 function. Numerical results show that the method is efficient.

  10. Design and Synthesis of Isosteviol Triazole Conjugates for Cancer Therapy

    OpenAIRE

    Ravil N. Khaybullin; Mei Zhang; Junjie Fu; Xiao Liang; Tammy Li; ALAN R. KATRITZKY; Paul Okunieff; Xin Qi

    2014-01-01

    One of the keys for successfully developing drugs against the broad spectrum of cancer cell types is structural diversity. In the current study, we focused on a family of isosteviol derivatives as potential novel antitumor agents. Isosteviol is a tetracyclic diterpenoid obtained by acid hydrolysis of steviol glycoside extracts isolated from abundant Stevia rebaudiana plants. In this work, we have designed and synthesized a panel of isosteviol triazole conjugates using “click” chemistry meth...

  11. Quinone-Amino Acid Conjugates Targeting Leishmania Amino Acid Transporters

    OpenAIRE

    Federica Prati; Adele Goldman-Pinkovich; Federica Lizzi; Federica Belluti; Roni Koren; Dan Zilberstein; Maria Laura Bolognesi

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxi...

  12. Improved QD-BRET conjugates for detection and imaging

    OpenAIRE

    Xing, Yun; So, Min-kyung; Koh, Ai-leen; Sinclair, Robert; Rao, Jianghong

    2008-01-01

    Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dots bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness & photostability, tunable emission, multiplexing) as well as the high sensitivity of...

  13. Invasive pneumococcal infection despite 7-valent conjugated vaccine

    Directory of Open Access Journals (Sweden)

    Sebastien Joye

    2013-03-01

    Full Text Available Despite good cover with 7-valent vaccination, invasive pneumococcal infections may still be misdiagnosed and may lead to lifethreatening situations or death in young children. New serotypes are emerging and, therefore, clinicians must keep a high level of suspicion in young children regardless of their vaccination status. We report three cases of invasive pneumococcal infection due to new serotypes not covered by the 7-valent conjugated vaccine, two of which led children to death.

  14. Plasmon-Polaron Coupling in Conjugated Polymer on Infrared Nanoantennas.

    Science.gov (United States)

    Wang, Zilong; Zhao, Jun; Frank, Bettina; Ran, Qiandong; Adamo, Giorgio; Giessen, Harald; Soci, Cesare

    2015-08-12

    We propose and demonstrate a novel type of coupling between polarons in a conjugated polymer and localized surface plasmons in infrared (IR) nanoantennas. The near-field interaction between plasmons and polarons is revealed by polarized photoinduced absorption measurements, probing mid-IR polaron transitions, and infrared-active vibrational modes of the polymer, which directly gauge the density of photogenerated charge carriers. This work proves the possibility of tuning the polaronic properties of organic semiconductors with plasmonic nanostructures.

  15. Intracellular Fate of Spherical Nucleic Acid Nanoparticle Conjugates

    OpenAIRE

    Wu, Xiaochen A.; Choi, Chung Hang J.; Zhang, Chuan; Hao, Liangliang; Mirkin, Chad A.

    2014-01-01

    Spherical nucleic acid (SNA) nanoparticle conjugates are a class of bionanomaterials that are extremely potent in many biomedical applications. Their unique ability to enter multiple mammalian cell types as single-entity agents arises from their novel three-dimensional architecture, which consists of a dense shell of highly oriented oligonucleotides chemically attached typically to a gold nanoparticle core. This architecture allows SNAs to engage certain cell surface receptors to facilitate e...

  16. Measuring the gain dynamics in a conjugated polymer film

    CERN Document Server

    Van den Berg, S A; Hooft, G W; Eliel, E R

    2004-01-01

    We present a simple method for measuring the gain decay time in a conjugated polymer film by optically exciting the film with two mutually delayed ultrashort pump pulses. When the pump is set at such a power level that amplified spontaneous emission marginally develops along the polymer waveguide, the total output emitted from its edge decays exponentially as a function of the interpulse delay. The corresponding decay time represents the decay time of the gain of the polymer material.

  17. Bioavailability of nanoemulsified conjugated linoleic acid for an antiobesity effect

    OpenAIRE

    Kim D; Park JH; Kweon DJ; Han GD

    2013-01-01

    Dongyeop Kim,1,3* Jin-Hong Park,2* Dae-Jun Kweon,2 Gi Dong Han11Department of Food Science and Technology, College of Natural Resources, Yeungnam University, Gyeongsan, Republic of Korea; 2BioHealth Convergence Center, Daegu Technopark, Daegu, Republic of Korea; 3Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan *These authors contributed equally to this workBackground: The aim of this study was to enhance the bioavailability of conjugated lin...

  18. Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition

    OpenAIRE

    Raimondi, Stefano; Amaretti, Alberto; Leonardi, Alan; Quartieri, Andrea; Gozzoli, Caterina; Rossi, Maddalena

    2016-01-01

    Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31 Bifidobacterium species were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged to B. breve and B. pseudocatenulatum. GC-MS revealed that CLA producer st...

  19. Bio-Conjugated Polycaprolactone Membranes: A Novel Wound Dressing

    OpenAIRE

    Cai, Elijah Zhengyang; Teo, Erin Yiling; Jing, Lim; Koh, Yun Pei; Qian, Tan Si; Wen, Feng; Lee, James Wai Kit; Hing, Eileen Chor Hoong; Yap, Yan Lin; Lee, Hanjing; Lee, Chuen Neng; Teoh, Swee-Hin; Lim,Jane; Lim, Thiam Chye

    2014-01-01

    Background The combination of polycaprolactone and hyaluronic acid creates an ideal environment for wound healing. Hyaluronic acid maintains a moist wound environment and accelerates the in-growth of granulation tissue. Polycaprolactone has excellent mechanical strength, limits inflammation and is biocompatible. This study evaluates the safety and efficacy of bio-conjugated polycaprolactone membranes (BPM) as a wound dressing. Methods 16 New Zealand white rabbits were sedated and local anaest...

  20. Self-organized supramolecules of π-conjugated rodlike polymers

    OpenAIRE

    Knaapila, Matti

    2004-01-01

    This thesis concerns fundamental self-organized aspects in π-conjugated polymers. Self-organization is the central issue in nanotechnology of soft condensed matter. The thesis focuses on the design and control of supramolecular hairy-rodlike molecules which are characterized by a thermotropic and preferentially aligned nanoscale structure. The major emphasis is on polypyridine, polyaniline, and polyfluorene. Because of their rodlike chain the formation of supramolecules is nontrivial. The und...

  1. ON CONE D.C. OPTIMIZATION AND CONJUGATE DUALITY

    Institute of Scientific and Technical Information of China (English)

    M. SEMU

    2003-01-01

    This paper derives first order necessary and sufficient conditions for unconstrained coned.c. Programming problems where the underlined space is partially ordered with respect to acone. These conditions are given in terms of directional derivatives and subdifferentials of thecomponent functions. Moreover, conjugate duality for cone d.c. Optimization is discussed andweak duality theorem is proved in a more general partially ordered linear topological vectorspace (generalizing the results in [11]).

  2. A conjugate heat transfer procedure for gas turbine blades.

    Science.gov (United States)

    Croce, G

    2001-05-01

    A conjugate heat transfer procedure, allowing for the use of different solvers on the solid and fluid domain(s), is presented. Information exchange between solid and fluid solution is limited to boundary condition values, and this exchange is carried out at any pseudo-time step. Global convergence rate of the procedure is, thus, of the same order of magnitude of stand-alone computations.

  3. Stereoselective sulphate conjugation of racemic terbutaline by human liver cytosol.

    OpenAIRE

    Walle, T; Walle, U K

    1990-01-01

    1. The enantioselectivity of the sulphation of racemic terbutaline by phenolsulphotransferases was examined in vitro using cytosol from human livers (n = 3) and [35S]-3'-phosphoadenosine-5'-phosphosulphate (PAP35S) as the sulphate donor. 2. The radioactive sulphate conjugate formed was isolated by h.p.l.c. and its enantiomers were separated intact by h.p.l.c. after chiral derivatization. 3. Sulphation of racemic terbutaline occurred with the same apparent Km value for both enantiomers (270 mi...

  4. Decomposition Theorems and Conjugate Pair in DK Spaces

    Institute of Scientific and Technical Information of China (English)

    Ji Zhen ZHOU; Yu Tian WU

    2014-01-01

    Let K be a right-continuous and nondecreasing function. A function f analytic in the unit disk D belongs to the space DK if ?D|f?(z)|2K(1-|z|2)dA(z)<∞. Decomposition theorems for DK spaces are established in this paper. As an application, we obtain a characterization of interpolation by functions in DK spaces. Furthermore, we characterize functions in DK spaces by conjugate pairs.

  5. Regioselectivity of conjugate additions to monoalkyl-1,4-benzoquinones

    OpenAIRE

    SNEZANA TRIFUNOVIC; MIROSLAV J. GASIC; MARIO ZLATOVIC; IRENA NOVAKOVIC; DUSAN SLADIC; TATJANA BOZIC

    2002-01-01

    The regioselectivity of the reaction of conjugate addition of thiols, amines, methanol and hydrogen chloride with the monoalkyl-1,4-benzoquinones avarone and 2-tert-butyl-1,4-benzoquinone was investigated. It was shown that the regioselectivity of the reaction is influenced by the electrophilicity of position 5 in unprotonated 2-alkylquinones, the increased electrophilicity of position 6 in acidic medium, and by the acidity of the intermediate hydroquinones.

  6. Regioselectivity of conjugate additions to monoalkyl-1,4-benzoquinones

    Directory of Open Access Journals (Sweden)

    SNEZANA TRIFUNOVIC

    2002-09-01

    Full Text Available The regioselectivity of the reaction of conjugate addition of thiols, amines, methanol and hydrogen chloride with the monoalkyl-1,4-benzoquinones avarone and 2-tert-butyl-1,4-benzoquinone was investigated. It was shown that the regioselectivity of the reaction is influenced by the electrophilicity of position 5 in unprotonated 2-alkylquinones, the increased electrophilicity of position 6 in acidic medium, and by the acidity of the intermediate hydroquinones.

  7. Daunomycin-TFO Conjugates for Downregulation of Gene Expression

    Science.gov (United States)

    Capobianco, Massimo L.; Catapano, Carlo V.

    Daunomycin has shown interesting properties as a stabilizing agent for the antigene methodology. This approach consists of targeting a polypurine region of a given gene, with a triplex forming oligonucleotide (TFO), realizing a triple helix complex (triplex), with the aim of down-regulating gene expression. This chapter describes the basic principles of the triplex approach, the chemistry underlining the binding of daunomycin to oligonucleotides, and some results of gene-inhibition obtained with daunomycin-TFO conjugates with different targets.

  8. Compatibilization of All-Conjugated Polymer Blends for Organic Photovoltaics.

    Science.gov (United States)

    Lombeck, Florian; Sepe, Alessandro; Thomann, Ralf; Friend, Richard H; Sommer, Michael

    2016-08-23

    Compatibilization of an immiscible binary blend comprising a conjugated electron donor and a conjugated electron acceptor polymer with suitable electronic properties upon addition of a block copolymer (BCP) composed of the same building blocks is demonstrated. Efficient compatibilization during melt-annealing is feasible when the two polymers are immiscible in the melt, i.e. above the melting point of ∼250 °C of the semicrystalline donor polymer P3HT. To generate immiscibility at these high temperatures, the acceptor polymer PCDTBT is equipped with fluorinated side chains leading to an increased Flory-Huggins interaction parameter. Compatibilization in bulk and thin films is demonstrated, showing that the photovoltaic performance of pristine microphase separated and nanostructured BCPs can also be obtained for compatibilized blend films containing low contents of 10-20 wt % BCP. Thermodynamically stable domain sizes range between several tens of microns for pure blends and ∼10 nm for pure block copolymers. In addition to controlling domain size, the amount of block copolymer added dictates the ratio of edge-on and face-on P3HT crystals, with compatibilized films showing an increasing amount of face-on P3HT crystals with increasing amount of compatibilizer. This study demonstrates the prerequisites and benefits of compatibilizing all-conjugated semicrystalline polymer blends for organic photovoltaics.

  9. Development of hematin conjugated PLGA nanoparticle for selective cancer targeting.

    Science.gov (United States)

    Amin, Md Lutful; Kim, Dami; Kim, SeJin

    2016-08-25

    Targeted nanomedicine for cancer therapy has gained widespread popularity and is being extensively explored. Porphyrins have intrinsic tumor localizing ability and have been studied for photodynamic therapy. However, they have not been used as cancer targeting agents for nanomedicines. In this study, PLGA nanoparticles were formulated and an iron-containing blood porphyrin, hematin was conjugated to the surface of the nanoparticles to investigate selectivity towards cancer cell and cellular internalization. Hematin was previously shown to facilitate growth and proliferation of cancer cells. PLGA nanoparticles were characterized by FE-SEM, AFM, DLS, and Zeta potential analyzer. The conjugation of hematin was confirmed by FTIR. HeLa cells were used to study tumor selectivity and uptake. Hematin conjugated particles (ζ potential: -15.19mV) showed higher affinity towards the cancer cells than the control particles. The result indicated that the particles were internalized by heme carrier protein-1. Together these data suggest that hematin is a promising cancer targeting material for nanotherapeutics. PMID:27260086

  10. Genome modifications and cloning using a conjugally transferable recombineering system

    Directory of Open Access Journals (Sweden)

    Mohammad J Hossain

    2015-12-01

    Full Text Available The genetic modification of primary bacterial disease isolates is challenging due to the lack of highly efficient genetic tools. Herein we describe the development of a modified PCR-based, λ Red-mediated recombineering system for efficient deletion of genes in Gram-negative bacteria. A series of conjugally transferrable plasmids were constructed by cloning an oriT sequence and different antibiotic resistance genes into recombinogenic plasmid pKD46. Using this system we deleted ten different genes from the genomes of Edwardsiella ictaluri and Aeromonas hydrophila. A temperature sensitive and conjugally transferable flp recombinase plasmid was developed to generate markerless gene deletion mutants. We also developed an efficient cloning system to capture larger bacterial genetic elements and clone them into a conjugally transferrable plasmid for facile transferring to Gram-negative bacteria. This system should be applicable in diverse Gram-negative bacteria to modify and complement genomic elements in bacteria that cannot be manipulated using available genetic tools.

  11. Conjugated polymelectrolyte assembly at water-oil interfaces

    Science.gov (United States)

    Liu, Feng; Huang, Caili; Thomas, Russell; Russell Team

    Conjugated polyelectrolytes featured with conjugated backbone and functional side chains are interesting optoelectronic materials and widely used to modify electrodes in electronic devices such as light emitting diodes and solar cells to enhance device performance. Conjugated polyelectrolyte can be designed to have alternating hydrophilic and hydrophobic side chains, and thus inducing interesting surface and interface properties. In this work, we using polyfluorene based material, to study its behavior at water-toluene interface. The aliphatic side-chains will favorably interact with toluene, and amine side-chains will interact with water, making this material a good surfactant. At interface the polymer chain is stretched to a Janus type of geometry. Flattened molecules will assemble into ultra thin films via pi-pi intermolecular stacking, and thus creating barriers between liquids. When liquid volume is reduced, jamming at interface will show up. These properties are strongly affected by the environment of the liquids, such as temperature and PH values, and polyelectrolyte diffusion to interfaces. This study leads to new methods to structure liquids using single component, which can be extended to applications such as electro-spinning or fabricate flow devices.

  12. Facile biosynthesis, separation and conjugation of gold nanoparticles to doxorubicin

    Science.gov (United States)

    Kumar, S. Anil; Peter, Yves-Alain; Nadeau, Jay L.

    2008-12-01

    Particle shape and size determine the physicochemical and optoelectronic properties of nanoscale materials, including optical absorption, fluorescence, and electric and magnetic moments. It is thus desirable to be able to synthesize and separate various particle shapes and sizes. Biosynthesis using microorganisms has emerged as a more ecologically friendly, simpler, and more reproducible alternative to chemical synthesis of metal and semiconductor nanoparticles, allowing the generation of rare forms such as triangles. Here we show that the plant pathogenic fungus Helminthosporum solani, when incubated with an aqueous solution of chloroaurate ions, produces a diverse mixture of extracellular gold nanocrystals in the size range from 2 to 70 nm. A plurality are polydisperse spheres, but a significant number are homogeneously sized rods, triangles, pentagons, pyramids, and stars. The particles can be separated according to their size and shape by using a sucrose density gradient in a tabletop microcentrifuge, a novel and facile approach to nanocrystal purification. Conjugation to biomolecules can be performed without further processing, as illustrated with the smallest fraction of particles which were conjugated to the anti-cancer drug doxorubicin (Dox) and taken up readily into HEK293 cells. The cytotoxicity of the conjugates was comparable to that of an equivalent concentration of Dox.

  13. How Geometric Distortions Scatter Electronic Excitations in Conjugated Macromolecules.

    Science.gov (United States)

    Shi, Tian; Li, Hao; Tretiak, Sergei; Chernyak, Vladimir Y

    2014-11-20

    Effects of disorder and exciton-phonon interactions are the major factors controlling photoinduced dynamics and energy-transfer processes in conjugated organic semiconductors, thus defining their electronic functionality. All-atom quantum-chemical simulations are potentially capable of describing such phenomena in complex "soft" organic structures, yet they are frequently computationally restrictive. Here we efficiently characterize how electronic excitations in branched conjugated molecules interact with molecular distortions using the exciton scattering (ES) approach as a fundamental principle combined with effective tight-binding models. Molecule geometry deformations are incorporated to the ES view of electronic excitations by identifying the dependence of the Frenkel-type exciton Hamiltonian parameters on the characteristic geometry parameters. We illustrate our methodology using two examples of intermolecular distortions, bond length alternation and single bond rotation, which constitute vibrational degrees of freedom strongly coupled to the electronic system in a variety of conjugated systems. The effect on excited-state electronic structures has been attributed to localized variation of exciton on-site energies and couplings. As a result, modifications of the entire electronic spectra due to geometric distortions can be efficiently and accurately accounted for with negligible numerical cost. The presented approach can be potentially extended to model electronic structures and photoinduced processes in bulk amorphous polymer materials.

  14. Meeting the challenge: prevention of pneumococcal disease with conjugate vaccines

    Directory of Open Access Journals (Sweden)

    Echániz-Avilés Irma Gabriela

    2001-01-01

    Full Text Available Streptococcus pneumoniae is one of the leading causes of both invasive and noninvasive diseases in the pediatric population and continues to represent a significant public health burden worldwide. The increasing incidence of antibioticresistant strains of the pathogen has complicated treatment and management of the various pneumococcal disease manifestations. Thus, the best management strategy may be the prevention of pneumococcal diseases through vaccination. Although several pneumococcal conjugate vaccines have been clinically studied in infants and children, only a 7-valent conjugate vaccine (PNCRM7; Prevnar®/Prevenar® is currently approved for the prevention of invasive disease. Vaccination with PNCRM7 is safe and effective in infants and young children. Routine vaccination with the conjugate vaccine could improve outcomes by safeguarding against the development of antibiotic-resistant strains of S. pneumoniae, thus simplifying the management of pneumococcal disease. Additionally, the overall costs associated with the treatment of pneumococcal diseases could be substantially reduced, particularly in developing countries. The time has come for fully applying this new advancement against S. pneumoniae, to benefit the children of the world. The Spanish version of this paper is available at: http://www.insp.mx/salud/index.html

  15. Compatibilization of All-Conjugated Polymer Blends for Organic Photovoltaics.

    Science.gov (United States)

    Lombeck, Florian; Sepe, Alessandro; Thomann, Ralf; Friend, Richard H; Sommer, Michael

    2016-08-23

    Compatibilization of an immiscible binary blend comprising a conjugated electron donor and a conjugated electron acceptor polymer with suitable electronic properties upon addition of a block copolymer (BCP) composed of the same building blocks is demonstrated. Efficient compatibilization during melt-annealing is feasible when the two polymers are immiscible in the melt, i.e. above the melting point of ∼250 °C of the semicrystalline donor polymer P3HT. To generate immiscibility at these high temperatures, the acceptor polymer PCDTBT is equipped with fluorinated side chains leading to an increased Flory-Huggins interaction parameter. Compatibilization in bulk and thin films is demonstrated, showing that the photovoltaic performance of pristine microphase separated and nanostructured BCPs can also be obtained for compatibilized blend films containing low contents of 10-20 wt % BCP. Thermodynamically stable domain sizes range between several tens of microns for pure blends and ∼10 nm for pure block copolymers. In addition to controlling domain size, the amount of block copolymer added dictates the ratio of edge-on and face-on P3HT crystals, with compatibilized films showing an increasing amount of face-on P3HT crystals with increasing amount of compatibilizer. This study demonstrates the prerequisites and benefits of compatibilizing all-conjugated semicrystalline polymer blends for organic photovoltaics. PMID:27482842

  16. Non-covalent interactions between carbon nanotubes and conjugated polymers.

    Science.gov (United States)

    Tuncel, Dönüs

    2011-09-01

    Carbon nanotubes (CNTs) are interest to many different disciplines including chemistry, physics, biology, material science and engineering because of their unique properties and potential applications in various areas spanning from optoelectronics to biotechnology. However, one of the drawbacks associated with these materials is their insolubility which limits their wide accessibility for many applications. Various approaches have been adopted to circumvent this problem including modification of carbon nanotube surfaces by non-covalent and covalent attachments of solubilizing groups. Covalent approach modification may alter the intrinsic properties of carbon nanotubes and, in turn make them undesirable for many applications. On the other hand, a non-covalent approach helps to improve the solubility of CNTs while preserving their intrinsic properties. Among many non-covalent modifiers of CNTs, conjugated polymers are receiving increasing attention and highly appealing because of a number of reasons. To this end, the aim of this feature article is to review the recent results on the conjugated polymer-based non-covalent functionalization of CNTs with an emphasis on the effect of conjugated polymers in the dispersibility/solubility, optical, thermal and mechanical properties of carbon nanotubes as well as their usage in the purification and isolation of a specific single-walled nanotube from the mixture of the various tubes.

  17. Development of conjugate shear bands during bulk simple shearing

    Science.gov (United States)

    Harris, L. B.; Cobbold, P. R.

    In rocks possessing a strong planar fabric, shear bands of constant shear sense and oriented at an oblique angle to the foliation are considered by many authors to be characteristic of a non-coaxial bulk deformation history, whereas conjugate shear bands are considered to indicate coaxial shortening. However, in two areas where bulk deformation history appears to be non-coaxial (Cap Corse, Corsica and Ile de Groix, Brittany), conjugate shear bands are observed. In order to investigate this problem, experiments were performed by bulk simple shearing using Plasticine as a rock analogue. When slip between layers of the model is permitted, shear bands of normal-fault geometry form with both the same and opposite shear sense as the bulk simple shearing at approximately the same angle with the layering (40°) irrespective of layer orientation in the undeformed state (for initial orientations of 50, 30 and 15°). Shear bands are initially formed within individual layers and may propagate across layer interfaces when further movement along these is inhibited. The existence of conjugate shear bands in Corsica and Ile de Groix is therefore not incompatible with a model of bulk simple shearing for these two regions. In field studies, one should perhaps exercise care in using shear bands to determine the kind of motion or the sense of bulk shearing.

  18. Fatty acid conjugation enhances the activities of antimicrobial peptides.

    Science.gov (United States)

    Li, Zhining; Yuan, Penghui; Xing, Meng; He, Zhumei; Dong, Chuanfu; Cao, Yongchang; Liu, Qiuyun

    2013-04-01

    Antimicrobial peptides are small molecules that play a crucial role in innate immunity in multi-cellular organisms, and usually expressed and secreted constantly at basal levels to prevent infection, but local production can be augmented upon an infection. The clock is ticking as rising antibiotic abuse has led to the emergence of many drug resistance bacteria. Due to their broad spectrum antibiotic and antifungal activities as well as anti-viral and anti-tumor activities, efforts are being made to develop antimicrobial peptides into future microbial agents. This article describes some of the recent patents on antimicrobial peptides with fatty acid conjugation. Potency and selectivity of antimicrobial peptide can be modulated with fatty acid tails of variable length. Interaction between membranes and antimicrobial peptides was affected by fatty acid conjugation. At concentrations above the critical miscelle concentration (CMC), propensity of solution selfassembly hampered binding of the peptide to cell membranes. Overall, fatty acid conjugation has enhanced the activities of antimicrobial peptides, and occasionally it rendered inactive antimicrobial peptides to be bioactive. Antimicrobial peptides can not only be used as medicine but also as food additives.

  19. Coordinate-Space Solver for Superfluid Many-Fermion Systems with Shifted Conjugate Orthogonal Conjugate Gradient Method

    CERN Document Server

    Jin, Shi; Roche, Kenneth; Wlazłowski, Gabriel

    2016-01-01

    Self-consistent approaches to superfluid many-fermion systems in 3-dimensions (and subsequent time-dependent approaches) require a large number of diagonalizations of very large dimension hermitian matrices, which results in enormous computational costs. We present an approach based on the shifted conjugate-orthogonal conjugate-gradient (COCG) method for the evaluation of the Green's function, from which we subsequently extract various densities (particle number, spin, current, kinetic energy, etc.) of a nuclear system needed in self-consistent approaches. The approach eschews the construction of the quasiparticle wavefunctions and their corresponding quasiparticle energies, which are never explicitly needed in any density functional approaches. As benchmarks we present calculations for nuclei with axial symmetry, including the ground state of spherical (magic or semi-magic) and axially deformed nuclei, the saddle-point in the $^{240}$Pu constrained fission path, and a vortex in the neutron star crust.

  20. Systemic aspects of conjugal resilience in couples with a child facing cancer and marrow transplantation

    Directory of Open Access Journals (Sweden)

    Julie Martin

    2016-09-01

    Full Text Available Introduction: The negative impact of paediatric cancer on parents is well known and is even greater when intensive treatments are used. This study aimed to describe how couples whose child has received a transplant for the treatment of leukaemia view conjugal resilience and to evaluate the role of we-ness as a precursor of conjugal adjustment. Methods: Four parental couples were interviewed. Interviews were analysed in two ways: inductive thematic analysis and rating of verbal content with the We-ness Coding Scale. Results: Participants report that conjugal resilience involves the identification of the couple as a team and cohesion in the couple. Being a team generates certain collaborative interactions that lead to conjugal resilience. A sense of we-ness in parents is associated with fluctuation in the frequency of themes. Discussion: Participants’ vision of conjugal resilience introduced novel themes. The sense of we-ness facilitates cohesion and the process of conjugal resilience.

  1. Seismic evidence of conjugate normal faulting: The 1994 Devil Canyon earthquake sequence near Challis, Idaho

    International Nuclear Information System (INIS)

    In this study, the term ''conjugate'' refers to faults that occur in two intersecting sets and coordinated kinematically, with each set being distinctive in both orientation and sense of shear (Davis, 1984). Contemporaneous activity along the conjugate faults is defined as occurring within the time frame of the mainshock-aftershock sequence (three weeks for this sequence and generally less than one month in other observed cases). Detailed recordings of microearthquakes from a dense array of temporary analog seismic stations are analyzed. The focal mechanisms and hypocenter spatial and temporal characteristics are combined with geological information to assess the style, geometry, timing, kinematics, and mechanics of conjugate normal faulting. The characteristics of conjugate normal faulting observed in the Devil Canyon sequence are compared to other conjugate normal faulting sequences, and strike-slip and thrust conjugate sequences worldwide

  2. Identification of a benzyladenine disaccharide conjugate produced during shoot organogenesis in Petunia leaf explants

    Energy Technology Data Exchange (ETDEWEB)

    Auer, C.A. (Univ. of Connecticute, Storrs, CT (United States)); Cohen, J.D. (Beltsville Agricultural Research Ctr., MD (United States))

    1993-06-01

    Prior studies of benzyladenine (BA) metabolism in Petunia hybrida Vilm. leaf explants during shoot organogenesis revealed the presence of an abundant unidentified BA conjugate. The BA conjugate, compound C, made up to 39% of the total pool of BA conjugates in two Petunia lines and was associated with an increased shoot organogenic response when compared with a third Petunia line that did not produce any compound C. Structural analysis of compound C utilizing fast atom bombardment mass spectrometry, two methods of carbohydrate analysis, ultraviolet absorption spectra, and Fourier transform infrared spectra identified it as a new cytokinin conjugate, 6-benzylamino-9-[O-glucopyranosyl-(1[yields]3)-ribofuranosyl]-purine. Based on our prior biological studies and the similarity of this compound to related cytokinin conjugates, this disaccharide cytokinin conjugate may be part of the interconvertible pool of cytokinins active in Petunia shoot organogenesis. 17 refs., 2 figs., 2 tabs.

  3. DNA-templated antibody conjugation for targeted drug delivery to cancer cells

    DEFF Research Database (Denmark)

    Liu, Tianqiang

    2016-01-01

    Monoclonal antibodies have been used for the treatment of cancer because of their specificity to tumor markers. However, intact unmodified antibodies used as single agent therapeutics sometimes are not curative. To overcome this, there is a trend to empower them with bioactive payloads (toxins......, chemotherapeutics, radionuclides, cytokines) by means of antibody conjugation. Conventional chemical modification techniques for the conjugation of antibodies result in highly heterogeneous mixtures. This heterogeneity is far from optimal since for therapeutic purpose antibody conjugates are better in homogeneous...... conjugation strategy. Recently, a site-selective antibody conjugation method called “DNA-templated protein conjugation (DTPC)” was developed by our group. The site-selective covalently attachment of single-stranded DNA (ssDNA) to proteins was achieved by using a metal-affinity DNA probe and DNA...

  4. Human Intestinal Cells Modulate Conjugational Transfer of Multidrug Resistance Plasmids between Clinical Escherichia coli Isolates

    DEFF Research Database (Denmark)

    Machado, Ana Manuel; Sommer, Morten

    2014-01-01

    Bacterial conjugation in the human gut microbiota is believed to play a major role in the dissemination of antibiotic resistance genes and virulence plasmids. However, the modulation of bacterial conjugation by the human host remains poorly understood and there is a need for controlled systems......-cultured with human intestinal cells. We show that filtered media from co-cultures contain a factor that reduces conjugation efficiency. Protease treatment of the filtered media eliminates this inhibition of conjugation. This data suggests that a peptide or protein based factor is secreted on the apical side...... of the intestinal cells exposed to bacteria leading to a two-fold reduction in conjugation efficiency. These results show that human gut epithelial cells can modulate bacterial conjugation and may have relevance to gene exchange in the gut....

  5. Enzymatic degradation behavior and cytocompatibility of silk fibroin–starch–chitosan conjugate membranes

    OpenAIRE

    Baran, E. T.; Tuzlakoglu, K.; Mano, J. F.; Reis, R. L.

    2012-01-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in α-amylase was more ...

  6. Synthesis and in Vitro Cytotoxicity of a Novel Conjugate of Polyamide and Phospholipid

    Institute of Scientific and Technical Information of China (English)

    Yi LIU; Yu Lin DENG; Rong ZHENG; Pei Long ZHANG; Hui ZHAI; Ke Zhong LIU; Chang Jin ZHU

    2006-01-01

    In order to increase the cell penetration and decrease the cytotoxicity of the synthetic molecule, we designed and synthesized a DNA-binding ligand, which was a conjugate of polyamide and phospholipid. We examined the differences in the effect on cytotoxicity between the conjugate and the native polyamide. As expected that the in vitro cytotoxicity of the conjugate was obviously lower than that of the native polyamide either in HeLa cells or SH-SY5Y neuroblastoma cells.

  7. Enzymatic degradation behavior and cytocompatibility of silk fibroin–starch–chitosan conjugate membranes

    International Nuclear Information System (INIS)

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in α-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: ► Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. ► The enzymatic biodegradation and the cytocompatibility of conjugates were tested. ► The conjugate with 30% starch composition was degraded by α-amylase significantly. ► Higher starch composition in conjugates prevented protease and lysozyme degradation. ► Fibroin incorporation effectively increased the cell proliferation of conjugates.

  8. Linkage structures strongly influence the binding cooperativity of DNA intercalators conjugated to triplex forming oligonucleotides.

    OpenAIRE

    1994-01-01

    Conjugation of DNA intercalators to triple helix forming oligodeoxynucleotides (ODN's) can enhance ODN binding properties and consequently their potential ability to modulate gene expression. To test the hypothesis that linkage structure could strongly influence the binding enhancement of intercalator conjugation with triplex forming ODN's, we have used a model system to investigate binding avidity of short oligomers conjugated to DNA intercalators through various linkages. Using a dA10.T10 t...

  9. Particle-in-a-Box Model of Exciton Absorption and Electroabsorption in Conjugated Polymers

    DEFF Research Database (Denmark)

    Pedersen, Thomas Garm

    2001-01-01

    The recently proposed particle-in-a-box model of one-dimensional excitons in conjugated polymers is applied in calculations of optical absorption and electroabsorption spectra. It is demonstrated that for polymers of long conjugation length a superposition of single exciton resonances produces...... a line shape characterized by a square-root singularity in agreement with experimental spectra near the absorption edge. The effects of finite conjugation length on both absorption and electroabsorption spectra are analyzed....

  10. A SELF-ADAPTIVE TECHNIQUE FOR A KIND OF NONLINEAR CONJUGATE GRADIENT METHODS

    Institute of Scientific and Technical Information of China (English)

    王丽平

    2004-01-01

    Conjugate gradient methods. are a class of important methods for unconstrained optimization, especially when the dimension is large. In 2001, Dai and Liao have proposed a new conjugate condition, based on it two nonlinear conjugate gradient methods are constructed. With trust region idea, this paper gives a self-adaptive technique for the two methods. The numerical results show that this technique works well for the given nonlinear optimization test problems.

  11. Preparation and testing of a Haemophilus influenzae Type b/Hepatitis B surface antigen conjugate vaccine.

    Science.gov (United States)

    An, So Jung; Woo, Joo Sung; Chae, Myung Hwa; Kothari, Sudeep; Carbis, Rodney

    2015-03-24

    The majority of conjugate vaccines focus on inducing an antibody response to the polysaccharide antigen and the carrier protein is present primarily to induce a T-cell dependent response. In this study conjugates consisting of poly(ribosylribitolphosphate) (PRP) purified from Haemophilus influenzae Type b bound to Hepatitis B virus surface antigen (HBsAg) virus like particles were prepared with the aim of inducing an antibody response to not only the PRP but also the HBsAg. A conjugate consisting of PRP bound to HBsAg via an adipic acid dihydrazide (ADH) spacer induced strong IgG antibodies to both the PRP and HBsAg. When conjugation was performed without the ADH spacer the induction of an anti-PRP response was equivalent to that seen by conjugate with the ADH spacer, however, a negligible anti-HBsAg response was induced. For comparison, PRP was conjugated to diphtheria toxoid (DT) and Vi polysaccharide purified from Salmonella Typhi conjugated to HBsAg both using an ADH spacer. The PRPAH-DT conjugate induced strong anti-PRP and anti-DT responses, the Vi-AHHBsAg conjugate induced a good anti-HBsAg response but not as strong as that induced by the PRPAH-HBsAg conjugate. This study demonstrated that in mice it was possible to induce robust antibody responses to both polysaccharide and carrier protein provided the conjugate has certain physico-chemical properties. A PRPAH-HBsAg conjugate with the capacity to induce anti-PRP and anti-HBsAg responses could be incorporated into a multivalent pediatric vaccine and simplify formulation of such a vaccine.

  12. Optical phase-conjugation in erioglaucine dye-doped thin film

    Indian Academy of Sciences (India)

    T Geethakrishnan; P K Palanisamy

    2006-02-01

    Optical phase-conjugation (OPC) has been demonstrated in erioglaucine (acid blue 9) dye-doped gelatin films via continuous-wave degenerate four-wave mixing (DFWM) using a low-power He-Ne laser at 633 nm. DFWM and holographic processes are found to contribute to the observed phase-conjugate signal. A maximum phase-conjugate beam reflectivity of about 0.24% has been observed in these dye-doped gelatin films.

  13. Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, Erkan T., E-mail: erkantur@metu.edu.tr; Tuzlakoglu, Kadriye, E-mail: kadriye@dep.uminho.pt; Mano, Joao F., E-mail: jmano@dep.uminho.pt; Reis, Rui L., E-mail: rgreis@dep.uminho.pt

    2012-08-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in {alpha}-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: Black-Right-Pointing-Pointer Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. Black-Right-Pointing-Pointer The enzymatic biodegradation and the cytocompatibility of conjugates were tested. Black-Right-Pointing-Pointer The conjugate with 30% starch composition was degraded by {alpha}-amylase significantly. Black-Right-Pointing-Pointer Higher starch composition in conjugates prevented protease and lysozyme degradation. Black-Right-Pointing-Pointer Fibroin incorporation effectively increased the cell proliferation of conjugates.

  14. Very Small Bandgap π-Conjugated Polymers with Extended Thienoquinoids.

    Science.gov (United States)

    Kawabata, Kohsuke; Saito, Masahiko; Osaka, Itaru; Takimiya, Kazuo

    2016-06-22

    The introduction of quinoidal character to π-conjugated polymers is one of the effective approaches to reducing the bandgap. Here we synthesized new π-conjugated polymers (PBTD4T and PBDTD4T) incorporating thienoquinoids 2,2'-bithiophene-5,5'-dione (BTD) and benzo[1,2-b:4,5-b']dithiophene-2,6-dione (BDTD) as strong electron-deficient (acceptor) units. PBTD4T showed a deep LUMO energy level of -3.77 eV and a small bandgap of 1.28 eV, which are similar to those of the analog using thieno[3,2-b]thiophene-2,5-dione (TTD) (PTTD4T). PBDTD4T had a much deeper LUMO energy level of -4.04 eV and a significantly smaller bandgap of 0.88 eV compared to those of the other two polymers. Interestingly, PBDTD4T showed high transparency in the visible region. The very small bandgap of PBDTD4T can be rationalized by the enhanced contribution of the resonance backbone structure in which the p-benzoquinodimethane skeleton in the BDTD unit plays a crucial role. PBTD4T and PBDTD4T exhibited ambipolar charge transport with more balanced mobilities between the hole and the electron than PTTD4T. We believe that the very small bandgap, i.e., the high near-infrared activity, as well as the well-balanced ambipolar property of the π-conjugated polymers based on these units would be of particular interest in the fabrication of next-generation organic devices.

  15. Optical Control of Living Cells Electrical Activity by Conjugated Polymers.

    Science.gov (United States)

    Martino, Nicola; Bossio, Caterina; Vaquero Morata, Susana; Lanzani, Guglielmo; Antognazza, Maria Rosa

    2016-01-28

    Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated polymers display several optimal properties as substrates for biological systems, such as good biocompatibility, excellent mechanical properties, cheap and easy processing technology, and possibility of deposition on light, thin and flexible substrates. These materials have been employed for cellular interfaces like neural probes, transistors for excitation and recording of neural activity, biosensors and actuators for drug release. Recent experiments have also demonstrated the possibility to use conjugated polymers for all-optical modulation of the electrical activity of cells. Several in-vitro study cases have been reported, including primary neuronal networks, astrocytes and secondary line cells. Moreover, signal photo-transduction mediated by organic polymers has been shown to restore light sensitivity in degenerated retinas, suggesting that these devices may be used for artificial retinal prosthesis in the future. All in all, light sensitive conjugated polymers represent a new approach for optical modulation of cellular activity. In this work, all the steps required to fabricate a bio-polymer interface for optical excitation of living cells are described. The function of the active interface is to transduce the light stimulus into a modulation of the cell membrane potential. As a study case, useful for in-vitro studies, a polythiophene thin film is used as the functional, light absorbing layer, and Human Embryonic Kidney (HEK-293) cells are employed as the biological component of the interface. Practical examples of successful control of the cell membrane potential upon stimulation with light pulses of different duration are provided. In particular, it is shown that both depolarizing and hyperpolarizing effects on the cell membrane can be achieved depending on the duration of the light stimulus. The reported

  16. Optical Control of Living Cells Electrical Activity by Conjugated Polymers.

    Science.gov (United States)

    Martino, Nicola; Bossio, Caterina; Vaquero Morata, Susana; Lanzani, Guglielmo; Antognazza, Maria Rosa

    2016-01-01

    Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated polymers display several optimal properties as substrates for biological systems, such as good biocompatibility, excellent mechanical properties, cheap and easy processing technology, and possibility of deposition on light, thin and flexible substrates. These materials have been employed for cellular interfaces like neural probes, transistors for excitation and recording of neural activity, biosensors and actuators for drug release. Recent experiments have also demonstrated the possibility to use conjugated polymers for all-optical modulation of the electrical activity of cells. Several in-vitro study cases have been reported, including primary neuronal networks, astrocytes and secondary line cells. Moreover, signal photo-transduction mediated by organic polymers has been shown to restore light sensitivity in degenerated retinas, suggesting that these devices may be used for artificial retinal prosthesis in the future. All in all, light sensitive conjugated polymers represent a new approach for optical modulation of cellular activity. In this work, all the steps required to fabricate a bio-polymer interface for optical excitation of living cells are described. The function of the active interface is to transduce the light stimulus into a modulation of the cell membrane potential. As a study case, useful for in-vitro studies, a polythiophene thin film is used as the functional, light absorbing layer, and Human Embryonic Kidney (HEK-293) cells are employed as the biological component of the interface. Practical examples of successful control of the cell membrane potential upon stimulation with light pulses of different duration are provided. In particular, it is shown that both depolarizing and hyperpolarizing effects on the cell membrane can be achieved depending on the duration of the light stimulus. The reported

  17. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Science.gov (United States)

    2010-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1115 Urinary bilirubin and its conjugates (nonquantitative)...

  18. 21 CFR 862.1187 - Conjugated sulfolithocholic acid (SLCG) test system.

    Science.gov (United States)

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1187 Conjugated sulfolithocholic acid (SLCG) test system. (a) Identification....

  19. Conjugate Etalon Spectral Imager (CESI) & Scanning Etalon Methane Mapper (SEMM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Conjugate Etalon Spectral Imaging (CESI) concept enables the development of miniature instruments with high spectral resolution, suitable for LEO missions...

  20. Integral mean of Green’s potentials and their conjugate

    Directory of Open Access Journals (Sweden)

    Vasyl'kiv, Ya. V.

    2013-06-01

    Full Text Available The best possible estimates for Lebesgue integral means $m_q(r,F; (1le q <+infty$ for the pair of functions $F= g+i:reve{g}$, here $g$ --- Green's potential, $reve{g}$ --- function conjugate to $g$, was obtained. It generalizes well-known results of Ya.V. Vasyl'kiv and A.A. Kondratyuk for logarithms $log; B$ of Blaschke products $B$ in terms of counting function $n(r,0,B$; $(0

  1. Graphite-Conjugated Pyrazines as Molecularly Tunable Heterogeneous Electrocatalysts.

    Science.gov (United States)

    Fukushima, Tomohiro; Drisdell, Walter; Yano, Junko; Surendranath, Yogesh

    2015-09-01

    Condensation of ortho-phenylenediamine derivatives with ortho-quinone moieties at edge planes of graphitic carbon generates graphite-conjugated pyrazines (GCPs) that are active for oxygen reduction electrocatalysis in alkaline aqueous electrolyte. Catalytic rates of oxygen reduction are positively correlated with the electrophilicity of the active site pyrazine unit and can be tuned by over 70-fold by appending electron-withdrawing substituents to the phenylenediamine precursors. Discrete molecular analogs containing pyrazine moieties display no activity above background under identical conditions. This simple bottom up method for constructing molecularly well-defined active sites on ubiquitous graphitic solids enables the rational design of tunable heterogeneous catalysts.

  2. Error bound results for convex inequality systems via conjugate duality

    CERN Document Server

    Bot, Radu Ioan

    2010-01-01

    The aim of this paper is to implement some new techniques, based on conjugate duality in convex optimization, for proving the existence of global error bounds for convex inequality systems. We deal first of all with systems described via one convex inequality and extend the achieved results, by making use of a celebrated scalarization function, to convex inequality systems expressed by means of a general vector function. We also propose a second approach for guaranteeing the existence of global error bounds of the latter, which meanwhile sharpens the classical result of Robinson.

  3. Synthesis of Conjugated Polyphenylene Dendritic β-Diketones

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; SHI Hua-Hong; CAO Yong

    2006-01-01

    An efficient synthesis of high generation conjugated polyphenylene dendrimer-based β-diketones was investigated using simple synthetic methods. The new dendrimer-based β-diketones were characterized by NMR, MS and elemental analysis. The UV-Vis and fluorescence spectra of theseβ-diketones in different solvents were investigated.The photoluminescent (PL) quantum yield and TG and DSC curves were also investigated. A new intermediate,1-bromo-3,5-diiodobenzene, was developed to synthesize high generation dendrimers with good yields.

  4. Program generator for the Incomplete Cholesky Conjugate Gradient (ICCG) method

    Energy Technology Data Exchange (ETDEWEB)

    Kuo-Petravic, G.; Petravic, M.

    1978-04-01

    The Incomplete Cholesky Conjugate Gradient (ICCG) method has been found very effective for the solution of sparse systems of linear equations. Its implementation on a computer, however, requires a considerable amount of careful coding to achieve good machine efficiency. Furthermore, the resulting code is necessarily inflexible and cannot be easily adapted to different problems. We present in this paper a code generator GENIC which, given a small amount of information concerning the sparsity pattern and size of the system of equations, generates a solver package. This package, called SOLIC, is tailor made for a particular problem and can be easily incorporated into any user program.

  5. Characterization of naproxen-polymer conjugates for drug-delivery.

    Science.gov (United States)

    Forte, Gianpiero; Chiarotto, Isabella; Giannicchi, Ilaria; Loreto, Maria Antonietta; Martinelli, Andrea; Micci, Roberta; Pepi, Federico; Rossi, Serena; Salvitti, Chiara; Stringaro, Annarita; Tortora, Luca; Vecchio Ciprioti, Stefano; Feroci, Marta

    2016-01-01

    The synthesis and the characterization of three new naproxen decorated polymers are described. A versatile and general approach is employed to link the drug to polymers, affording the derivatives with a very high degree of purity. The release of the drug from the conjugates proved to be exceptionally slow, even in acidic aqueous media, and the kinetic of the process seems to be triggered by their solubility in water. On the other hand, the interesting outcome of the first ex vivo drug release experiments on human blood samples makes this preliminary study valuable for future investigations on the use of these polymeric prodrugs in in vivo treatment of inflammatory states.

  6. Remark on charge conjugation in the non relativistic limit

    OpenAIRE

    Cabo, A.; Cervantes, D. B.; Rojas, H. Perez; Socolovsky, M.

    2005-01-01

    We study the non relativistic limit of the charge conjugation operation $\\cal C$ in the context of the Dirac equation coupled to an electromagnetic field. The limit is well defined and, as in the relativistic case, $\\cal C$, $\\cal P$ (parity) and $\\cal T$ (time reversal) are the generators of a matrix group isomorphic to a semidirect sum of the dihedral group of eight elements and $\\Z_2$. The existence of the limit is supported by an argument based in quantum field theory. Also, and most impo...

  7. Noise-Immune Conjugate Large-Area Atom Interferometers

    International Nuclear Information System (INIS)

    We present a pair of simultaneous conjugate Ramsey-Borde atom interferometers using large (20(ℎ/2π)k)-momentum transfer beam splitters, where (ℎ/2π)k is the photon momentum. Simultaneous operation allows for common-mode rejection of vibrational noise. This allows us to surpass the enclosed space-time area of previous interferometers with a splitting of 20(ℎ/2π)k by a factor of 2500. Using a splitting of 10(ℎ/2π)k, we demonstrate a 3.4 ppb resolution in the measurement of the fine structure constant. Examples for applications in tests of fundamental laws of physics are given.

  8. Comparative cytotoxicity of quantum dot and gold conjugates

    Science.gov (United States)

    Nadeau, Jay; Kumar, Anil; Dumas, Eve-Marie

    2009-02-01

    Nanoparticle toxicity is of interest for the design of anti-bacterial and anti-cancer agents, and also for development of regulations for their safe handling and disposal. However, the same reactivity that makes nanoparticles show unique optical properties also makes them interact with standard cytotoxicity agents, causing false positive and/or false negative results. We discuss which cytotoxicity assays are most likely to work with nanoparticles and which are to be avoided, and present some results on comparative cytotoxicity of different types of conjugates.

  9. Hydrochromic conjugated polymers for human sweat pore mapping.

    Science.gov (United States)

    Lee, Joosub; Pyo, Minkyeong; Lee, Sang-hwa; Kim, Jaeyong; Ra, Moonsoo; Kim, Whoi-Yul; Park, Bum Jun; Lee, Chan Woo; Kim, Jong-Man

    2014-04-29

    Hydrochromic materials have been actively investigated in the context of humidity sensing and measuring water contents in organic solvents. Here we report a sensor system that undergoes a brilliant blue-to-red colour transition as well as 'Turn-On' fluorescence upon exposure to water. Introduction of a hygroscopic element into a supramolecularly assembled polydiacetylene results in a hydrochromic conjugated polymer that is rapidly responsive (polymer. As a result, the sensor can be used to construct a precise map of active sweat pores on fingertips. The sensor technology, developed in this study, has the potential of serving as new method for fingerprint analysis and for the clinical diagnosis of malfunctioning sweat pores.

  10. Multifunctional non-viral delivery systems based on conjugated polymers.

    Science.gov (United States)

    Yang, Gaomai; Lv, Fengting; Wang, Bing; Liu, Libing; Yang, Qiong; Wang, Shu

    2012-12-01

    Multifunctional nanomaterials with simultaneous therapeutic and imaging functions explore new strategies for the treatment of various diseases. Conjugated polymers (CPs) are considered as novel candidates to serve as multifunctional delivery systems due to their high fluorescence quantum yield, good photostability, and low cytotoxicity. Highly sensitive sensing and imaging properties of CPs are well reviewed, while the applications of CPs as delivery systems are rarely covered. This feature article mainly focuses on CP-based multifunctional non-viral delivery systems for drug, protein, gene, and cell delivery. Promising directions for the further development of CP-based delivery systems are also discussed.

  11. Nonlinear Optical Response of Conjugated Polymer to Electric Field

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-fang; ZHUANG De-xin; CUI Bin

    2005-01-01

    The organic π-conjugated polymers are of major interest materials for the use in electro-optical and nonlinear optical devices. In this work, for a selected polyacetylene chain, the optical absorption spectra in UV/Vis regime as well as the linear polarizabilitiy and nonlinear hyperpolarizability are calculated by using quantum chemical ab initio and semiempirical methods. The relationship of its optical property to electric field is obtained. Some physical mechanism of electric field effect on molecular optical property is discussed by means of electron distribution and intramolecular charge transfer.

  12. A DSC STUDY OF PHOTOPOLYMERIZATION OF POLYESTERS CONTAINING CONJUGATED DIACETYLENES

    Institute of Scientific and Technical Information of China (English)

    Yao-wen Bai; Xiao-fang Chen; Dong Zhang; Xin-hua Wan; Qi-feng Zhou

    2000-01-01

    The photopolymerization of two kinds of prepolyesters containing conjugated diacetylene (PDA-6 and PDA-12)was investigated using DSC. By measuring the endothermic enthalpy of the prepolymers after different UV-irradiation times,the polymerizations were found to follow the first-order rate law which agreed with the results of other investigators using a different method. The endothermic enthalpy measurements of PDA-6 and PDA-12 before UV-irradiation precluded the possibility that the decrease of endothermic enthalpy was caused by thermal polymerization.

  13. Conjugated Linoleic Acid: Chemical Structure, Sources and Biological Properties

    OpenAIRE

    AYDIN, Rahim

    2005-01-01

    Conjugated linoleic acid (CLA) is a group of geometrical and positional isomers of linoleic acid (C18:2, cis-9, cis-12). In contrast to linoleic acid, double bonds in CLA are usually located at positions 9 and 11 or 10 and 12 and each double bond can be either in the cis or trans configuration. Meat and dairy products from ruminant animals (such as milk, butter, yogurt and cheese) are the principal natural sources of CLA in the human diet. Egg and meat products from poultry contain less CLA t...

  14. Synthesis and study of conjugated polymers containing Di- or Triphenylamine

    Energy Technology Data Exchange (ETDEWEB)

    Sukwattanasinitt, M.

    1996-06-21

    This thesis consists of two separate parts. The first part addresses the synthesis and study of conjugated polymers containing di- or triphenylamine. Two types of polymers: linear polymers and dendrimers, were synthesized. The polymers were characterized by NMR, IR, UV, GPC, TGA and DSC. Electronic and optical properties of the polymers were studied through the conductivity measurements and excitation- emission spectra. the second part of this thesis deals with a reaction of electron-rich acetylenes with TCNE. The discovery of the reaction from charge transfer complex studies and the investigation of this reaction on various electron-rich acetylenes are presented.

  15. Conjugate gradient solvers on Intel Xeon Phi and NVIDIA GPUs

    CERN Document Server

    Kaczmarek, O; Steinbrecher, P; Wagner, M

    2014-01-01

    Lattice Quantum Chromodynamics simulations typically spend most of the runtime in inversions of the Fermion Matrix. This part is therefore frequently optimized for various HPC architectures. Here we compare the performance of the Intel Xeon Phi to current Kepler-based NVIDIA Tesla GPUs running a conjugate gradient solver. By exposing more parallelism to the accelerator through inverting multiple vectors at the same time, we obtain a performance greater than 300 GFlop/s on both architectures. This more than doubles the performance of the inversions. We also give a short overview of the Knights Corner architecture, discuss some details of the implementation and the effort required to obtain the achieved performance.

  16. Synthesis of novel fullerene α-amino acid conjugates

    Institute of Scientific and Technical Information of China (English)

    Jing Zhang; Yan Xia Wang; Feng Kang; Ying Ya Shao; Zong Jie Li; Xin Lin Yang

    2008-01-01

    Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas)and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.

  17. Sulbactomax prevents antimicrobial resistance development by inhibition of conjugal transfer of F plasmids

    Directory of Open Access Journals (Sweden)

    Manu Chaudhary

    2012-03-01

    Full Text Available Aims: To evaluate the effect of EDTA on conjugation and plasmid transfer also to study the effect of different antibiotics on the conjugation. Methods and Results: The minimum inhibitory concentration (MIC of each antibacterial agent was determined using a broth dilution method. In-vitro conjugation study was performed in the presence of different concentration of EDTA. Following selection of appropriate concentration of EDTA which inhibits conjugation process and susceptibility profiles, the same concentration was corelated with Sulbactomax and a comparative study against ceftriaxone and ceftriaxone+sulbactam without EDTA was performed. Further to confirm the inhibition of conjugal transfer of plasmid, plasmid DNA was isolated from donor, recipient and transconjugates and processed for electrophoresis. Results of in vitro study shows that EDTA when used alone strongly inhibits conjugation process at 10 mM. Sulbactomax at half of MIC strongly inhibited the conjugation process as compared to ceftriaxone and ceftriaxone+sulbactam without EDTA. Further, it is clearly evident from agarose gel electrophoresis that conjugation process is inhibited by EDTA alone at 10 mM and higher as well as Sulbactomax. Conclusions: The results obtained in the present study, suggests that EDTA alone at 10 mM and at a very low concentration Sulbactomax inhibits the conjugation process and plasmid transfer. Thus, the inhibition of conjugation process is potentially a novel antimicrobial approach in the prevention of transfer of antibiotic resistance. Significance and Impact of Study: The increasing prevalence of microbial pathogens which are resistant to antibiotics has been encouraging investigation of new strategies for controlling bacterial infections. Conjugative plasmids are potential targets because of the high frequency of antibiotic resistance arising from conjugation and conjugative transfer of plasmid DNA by which antibiotic resistance genes spread between

  18. Linkers Having a Crucial Role in Antibody-Drug Conjugates.

    Science.gov (United States)

    Lu, Jun; Jiang, Feng; Lu, Aiping; Zhang, Ge

    2016-01-01

    Antibody-drug conjugates (ADCs) comprised of a desirable monoclonal antibody, an active cytotoxic drug and an appropriate linker are considered to be an innovative therapeutic approach for targeted treatment of various types of tumors and cancers, enhancing the therapeutic parameter of the cytotoxic drug and reducing the possibility of systemic cytotoxicity. An appropriate linker between the antibody and the cytotoxic drug provides a specific bridge, and thus helps the antibody to selectively deliver the cytotoxic drug to tumor cells and accurately releases the cytotoxic drug at tumor sites. In addition to conjugation, the linkers maintain ADCs' stability during the preparation and storage stages of the ADCs and during the systemic circulation period. The design of linkers for ADCs is a challenge in terms of extracellular stability and intracellular release, and intracellular circumstances, such as the acid environment, the reducing environment and cathepsin, are considered as the catalysts to activate the triggers for initiating the cleavage of ADCs. This review discusses the linkers used in the clinical and marketing stages for ADCs and details the fracture modes of the linkers for the further development of ADCs. PMID:27089329

  19. Graphite-Conjugated Rhenium Catalysts for Carbon Dioxide Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Seokjoon; Gallagher, James R.; Miller, Jeffrey T.; Surendranath, Yogesh

    2016-02-17

    Condensation of fac-Re(5,6-diamino-1,10-phenanthroline)(CO)(3)Cl to o-quinone edge defects on graphitic carbon surfaces generates graphite-conjugated rhenium (GCC-Re) catalysts that are highly active for CO2 reduction to CO in acetonitrile electrolyte. X-ray photo-electron and X-ray absorption spectroscopies establish the formation of surface-bound Re centers with well-defined coordination environments. GCC-Re species on glassy carbon surfaces display catalytic currents greater than 50 mA cm(-2) with 96 +/- 3% Faradaic efficiency for CO production. Normalized for the number of Re active sites, GCC-Re catalysts exhibit higher turnover frequencies than that of a soluble molecular analogue, fac-Re(1,10-phenanthroline)(CO)(3)Cl, and turnover numbers greater than 12,000. In contrast to the molecular analogue, GCC-Re surfaces display a Tafel slope of 150 mV/decade, indicative of a catalytic mechanism involving rate-limiting one-electron transfer. This work establishes graphite conjugation as a powerful strategy for generating well-defined, tunable, heterogeneous electrocatalysts on ubiquitous graphitic carbon surfaces.

  20. Nanoparticles of Fluorescent Conjugated Polymers: Novel Ion-Selective Optodes.

    Science.gov (United States)

    Kłucińska, Katarzyna; Stelmach, Emilia; Kisiel, Anna; Maksymiuk, Krzysztof; Michalska, Agata

    2016-06-01

    A novel type of ion-selective nano-optode is proposed, in which a conjugated polymer is used as optical transducer and nanoprobe material. Thus, contrary to most of the proposed optodes, the response does not require presence of pH-sensitive dye in the sensor. The conjugated polymer nanosensor material is in partially oxidized form-it is bearing positive charges and its emission is quenched. The receptor is an optically silent uncharged ionophore selective for the analyte cation. When a binding event occurs, positive charges are formed in the nanosphere, leading to a decrease in the oxidation state of the polymer, in the absence of redox potential change, resulting in increased emission. This general approach herein proposed results in a simple sensor, benefitting from a novel optical transduction mechanism and high lipophilicity of the polymer matrix that results in linear responses over a broad concentration range of analyte. For the model system studied, the linear dependence of emission intensity on the logarithm of analyte (K(+)) concentration was obtained for a broad range from 10(-5) M to 0.1 M. PMID:27136386

  1. Crystallization-driven assembly of conjugated-polymer-based nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, Ryan C. [Univ. of Massachusetts, Amherst, MA (United States). Polymer Science & Engineering

    2016-10-15

    The goal of this project has been to improve our ability to simultaneously control the organization, and therefore the opto-electronic properties, of conjugated-polymer based materials across three different length-scales: 1) the molecular scale, in the sense of controlling growth and functionalization of highly crystalline semiconducting organic materials capable of efficient charge transport, 2) the nanoscale, in terms of positioning n- and p-type materials with domain sizes comparable to exciton diffusion lengths (~ 10 nm) to facilitate charge separation, and 3) the colloidal scale, such that well-defined crystalline nanoscale building blocks can be hierarchically organized into device layers. As described in more detail below, the project was successful in generating powerful new approaches to, and improved fundamental understanding of, processing and self-assembly of organic and hybrid semiconducting materials across all three length-scales. Although the goals of the project were formulated with primarily photovoltaic architectures in mind, the outcomes of the project have significant implications for a variety of conjugated-polymer-based devices including field-effect-transistors for sensors and logic devices, as well as potentially thermoelectrics and battery electrode materials. The project has resulted in 10 peer-reviewed publications to date [1-10], with several additional manuscripts currently in preparation.

  2. Impacts of the 13-Valent Pneumococcal Conjugate Vaccine in Children.

    Science.gov (United States)

    Esposito, Susanna; Principi, Nicola

    2015-01-01

    Applications of the heptavalent pneumococcal conjugate vaccine (PCV7) in the pediatric immunization schedule have dramatically reduced the incidence of pneumococcal diseases in both vaccinated children and unvaccinated individuals of all ages. However, increased infections caused by non-PCV7 serotypes have been reported by several groups. To overcome this problem, new vaccines covering more serotypes including the emerging serotypes have been developed. The 13-valent pneumococcal conjugate vaccine (PCV13) currently covers the 7 PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) and 6 additional serotypes 1, 3, 5, 6A, 7F, and 19A. After the first year of PCV13 applications in the immunization schedule in young children, global evaluation studies demonstrated that PCV13 provided a wider coverage and more effective prevention than PCV7 against invasive pneumococcal diseases (IPDs), mucosal pneumococcal diseases, and pneumococcal carriage. We reviewed the effects of PCV13 in the control of pneumococcal diseases in children based on previous studies.

  3. Swift Electrofluorochromism of Donor-Acceptor Conjugated Polytriphenylamines.

    Science.gov (United States)

    Sun, Jingwei; Liang, Ziqi

    2016-07-20

    Electrofluorochromic (EFC) materials, which exhibit electrochemically controllable fluorescence, hold great promise in optoelectronic devices and biological analysis. Here we design such donor-acceptor (D-A) conjugated polymers-P(TPACO) and P(TCEC)-that contain the same electron-rich and oxidizable polytriphenylamine (PTPA) as π-backbone, yet with different electron-deficient ketone and cyano units as pendant groups, respectively. They both exhibit solvatochromic effects due to intrinsic characteristics of intramolecular charge transfer (ICT). Compared to P(TPACO), P(TCEC) shows stronger ICT, which leads to higher electrochemical oxidation potential and lower ion diffusion coefficient. Moreover, both polymers present simultaneous electrochromic (EC) and EFC behaviors with multistate display and remarkably rapid fluorescence response. The response time of P(TPACO) is as short as 0.19 s, nearly 4-fold faster than that of P(TCEC) (0.92 s). Such rapid response is found to be determined by the ion diffusion coefficient which is associated with the ICT nature. Finally, the EFC display device based on P(TPACO) is successfully demonstrated, which shows green fluorescence ON/OFF switching upon applied potentials. This work has successfully demonstrated that swift EFCs can be achieved by rational modulation of the ICT effect in such D-A conjugated polymers. PMID:27347724

  4. Conjugate heat transfer analysis of double pane windows

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Orhan [Department of Mechanical Engineering, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2006-02-01

    This study numerically analyzes conjugate heat transfer through a double pane window using a finite difference technique. The aim of the study is to determine the thermal optimum air layer thickness between the two panes for different climates. Four different cities of Turkey, representing different climate conditions are considered: Ankara, Antalya, Kars and Trabzon. Here, much more realistic boundary conditions considered for panes than those considered in Aydin (Energy and Buildings 2000; 32:303-8). Aydin (2000) assumed panes as isothermal surfaces, while, here, a conjugate heat transfer analysis is applied. Two different boundary conditions are applied for the outer surfaces facing inside and outside: constant temperature and convection. The height of the window, H is chosen 80cm and the thickness of each pane is set 4mm. The effect of air layer thickness varying between 3 and 40mm on the average Nusselt number and the heat flux through the inner pane. It was shown that energy losses through the double pane windows can be considerably reduced by optimizing thickness of the air layer. It is also shown that filling the space between the glass panes with a gas having a lower thermal conductivity instead of air reduces the insulating value of the window, (author)

  5. Concanavalin A conjugated biodegradable nanoparticles for oral insulin delivery

    International Nuclear Information System (INIS)

    Major research issues in oral protein delivery include the stabilization of protein in delivery devices which could increase its oral bioavailability. The study deals with development of oral insulin delivery system utilizing biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and modifying its surface with Concanavalin A to increase lymphatic uptake. Surface-modified PLGA nanoparticles were characterized for conjugation efficiency of ligand, shape and surface morphology, particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro drug release. Stability of insulin in the developed formulation was confirmed by SDS-PAGE, and integrity of entrapped insulin was assessed using circular dichroism spectrum. Ex vivo study was performed on Wistar rats, which exhibited the higher intestinal uptake of Con A conjugated nanoparticles. In vivo study performed on streptozotocin-induced diabetic rats which indicate that a surface-modified nanoparticle reduces blood glucose level effectively within 4 h of its oral administration. In conclusion, the present work resulted in successful production of Con A NPs bearing insulin with sustained release profile, and better absorption and stability. The Con A NPs showed high insulin uptake, due to its relative high affinity for non-reducing carbohydrate residues i.e., fucose present on M cells and have the potential for oral insulin delivery in effective management of Type 1 diabetes condition.

  6. Conjugate Compressible Fluid Flow and Heat Transfer in Ducts

    Science.gov (United States)

    Cross, M. F.

    2011-01-01

    A computational approach to modeling transient, compressible fluid flow with heat transfer in long, narrow ducts is presented. The primary application of the model is for analyzing fluid flow and heat transfer in solid propellant rocket motor nozzle joints during motor start-up, but the approach is relevant to a wide range of analyses involving rapid pressurization and filling of ducts. Fluid flow is modeled through solution of the spatially one-dimensional, transient Euler equations. Source terms are included in the governing equations to account for the effects of wall friction and heat transfer. The equation solver is fully-implicit, thus providing greater flexibility than an explicit solver. This approach allows for resolution of pressure wave effects on the flow as well as for fast calculation of the steady-state solution when a quasi-steady approach is sufficient. Solution of the one-dimensional Euler equations with source terms significantly reduces computational run times compared to general purpose computational fluid dynamics packages solving the Navier-Stokes equations with resolved boundary layers. In addition, conjugate heat transfer is more readily implemented using the approach described in this paper than with most general purpose computational fluid dynamics packages. The compressible flow code has been integrated with a transient heat transfer solver to analyze heat transfer between the fluid and surrounding structure. Conjugate fluid flow and heat transfer solutions are presented. The author is unaware of any previous work available in the open literature which uses the same approach described in this paper.

  7. Functional characterization of Corynebacterium glutamicum mycothiol S-conjugate amidase.

    Directory of Open Access Journals (Sweden)

    Meiru Si

    Full Text Available The present study focuses on the genetic and biochemical characterization of mycothiol S-conjugate amidase (Mca of Corynebacterium glutamicum. Recombinant C. glutamicum Mca was heterologously expressed in Escherichia coli and purified to apparent homogeneity. The molecular weight of native Mca protein determined by gel filtration chromatography was 35 kDa, indicating that Mca exists as monomers in the purification condition. Mca showed amidase activity with mycothiol S-conjugate of monobromobimane (MSmB in vivo while mca mutant lost the ability to cleave MSmB. In addition, Mca showed limited deacetylase activity with N-acetyl-D-glucosamine (GlcNAc as substrate. Optimum pH for amidase activity was between 7.5 and 8.5, while the highest activity in the presence of Zn2+ confirmed Mca as a zinc metalloprotein. Amino acid residues conserved among Mca family members were located in C. glutamicum Mca and site-directed mutagenesis of these residues indicated that Asp14, Tyr137, His139 and Asp141 were important for activity. The mca deletion mutant showed decreased resistance to antibiotics, alkylating agents, oxidants and heavy metals, and these sensitive phenotypes were recovered in the complementary strain to a great extent. The physiological roles of Mca in resistance to various toxins were further supported by the induced expression of Mca in C. glutamicum under various stress conditions, directly under the control of the stress-responsive extracytoplasmic function-sigma (ECF-σ factor SigH.

  8. Complexation of amyloid fibrils with charged conjugated polymers.

    Science.gov (United States)

    Ghosh, Dhiman; Dutta, Paulami; Chakraborty, Chanchal; Singh, Pradeep K; Anoop, A; Jha, Narendra Nath; Jacob, Reeba S; Mondal, Mrityunjoy; Mankar, Shruti; Das, Subhadeep; Malik, Sudip; Maji, Samir K

    2014-04-01

    It has been suggested that conjugated charged polymers are amyloid imaging agents and promising therapeutic candidates for neurological disorders. However, very less is known about their efficacy in modulating the amyloid aggregation pathway. Here, we studied the modulation of Parkinson's disease associated α-synuclein (AS) amyloid assembly kinetics using conjugated polyfluorene polymers (PF, cationic; PFS, anionic). We also explored the complexation of these charged polymers with the various AS aggregated species including amyloid fibrils and oligomers using multidisciplinary biophysical techniques. Our data suggests that both polymers irrespective of their different charges in the side chains increase the fibrilization kinetics of AS and also remarkably change the morphology of the resultant amyloid fibrils. Both polymers were incorporated/aligned onto the AS amyloid fibrils as evident from electron microscopy (EM) and atomic force microscopy (AFM), and the resultant complexes were structurally distinct from their pristine form of both polymers and AS supported by FTIR study. Additionally, we observed that the mechanism of interactions between the polymers with different species of AS aggregates were markedly different.

  9. Concanavalin A conjugated biodegradable nanoparticles for oral insulin delivery

    Energy Technology Data Exchange (ETDEWEB)

    Hurkat, Pooja; Jain, Aviral; Jain, Ashish; Shilpi, Satish; Gulbake, Arvind; Jain, Sanjay K., E-mail: drskjainin@yahoo.com [Dr. Hari Singh Gour Vishwavidyalaya, Pharmaceutics Research Projects Laboratory, Department of Pharmaceutical Sciences (India)

    2012-11-15

    Major research issues in oral protein delivery include the stabilization of protein in delivery devices which could increase its oral bioavailability. The study deals with development of oral insulin delivery system utilizing biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and modifying its surface with Concanavalin A to increase lymphatic uptake. Surface-modified PLGA nanoparticles were characterized for conjugation efficiency of ligand, shape and surface morphology, particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro drug release. Stability of insulin in the developed formulation was confirmed by SDS-PAGE, and integrity of entrapped insulin was assessed using circular dichroism spectrum. Ex vivo study was performed on Wistar rats, which exhibited the higher intestinal uptake of Con A conjugated nanoparticles. In vivo study performed on streptozotocin-induced diabetic rats which indicate that a surface-modified nanoparticle reduces blood glucose level effectively within 4 h of its oral administration. In conclusion, the present work resulted in successful production of Con A NPs bearing insulin with sustained release profile, and better absorption and stability. The Con A NPs showed high insulin uptake, due to its relative high affinity for non-reducing carbohydrate residues i.e., fucose present on M cells and have the potential for oral insulin delivery in effective management of Type 1 diabetes condition.

  10. Sequence-selective DNA recognition with peptide-bisbenzamidine conjugates.

    Science.gov (United States)

    Sánchez, Mateo I; Vázquez, Olalla; Vázquez, M Eugenio; Mascareñas, José L

    2013-07-22

    Transcription factors (TFs) are specialized proteins that play a key role in the regulation of genetic expression. Their mechanism of action involves the interaction with specific DNA sequences, which usually takes place through specialized domains of the protein. However, achieving an efficient binding usually requires the presence of the full protein. This is the case for bZIP and zinc finger TF families, which cannot interact with their target sites when the DNA binding fragments are presented as isolated monomers. Herein it is demonstrated that the DNA binding of these monomeric peptides can be restored when conjugated to aza-bisbenzamidines, which are readily accessible molecules that interact with A/T-rich sites by insertion into their minor groove. Importantly, the fluorogenic properties of the aza-benzamidine unit provide details of the DNA interaction that are eluded in electrophoresis mobility shift assays (EMSA). The hybrids based on the GCN4 bZIP protein preferentially bind to composite sequences containing tandem bisbenzamidine-GCN4 binding sites (TCAT⋅AAATT). Fluorescence reverse titrations show an interesting multiphasic profile consistent with the formation of competitive nonspecific complexes at low DNA/peptide ratios. On the other hand, the conjugate with the DNA binding domain of the zinc finger protein GAGA binds with high affinity (KD≈12 nM) and specificity to a composite AATTT⋅GAGA sequence containing both the bisbenzamidine and the TF consensus binding sites.

  11. Aptamer conjugated silver nanoparticles for the detection of interleukin 6

    Science.gov (United States)

    Locke, Andrea K.; Norwood, Nicole; Marks, Haley L.; Schechinger, Monika; Jackson, George W.; Graham, Duncan; Coté, Gerard L.

    2016-03-01

    The controlled assembly of plasmonic nanoparticles by a molecular binding event has emerged as a simple yet sensitive methodology for protein detection. Metallic nanoparticles (NPs) coated with functionalized aptamers can be utilized as biosensors by monitoring changes in particle optical properties, such as the LSPR shift and enhancement of the SERS spectra, in the presence of a target protein. Herein we test this method using two modified aptamers selected for the protein biomarker interleukin 6, an indicator of the dengue fever virus and other diseases including certain types of cancers, diabetes, and even arthritis. IL6 works by inducing an immunological response within the body that can be either anti-inflammatory or pro-inflammatory. The results show that the average hydrodynamic diameter of the NPs as measured by Dynamic Light Scattering was ~42 nm. After conjugation of the aptamers, the peak absorbance of the AgNPs shifted from 404 to 408 nm indicating a surface modification of the NPs due to the presence of the aptamer. Lastly, preliminary results were obtained showing an increase in SERS intensity occurs when the IL-6 protein was introduced to the conjugate solution but the assay will still need to be optimized in order for it to be able to monitor varying concentration changes within and across the desired range.

  12. Strong conjugation actions induced by flags of exact Borel subalgebras

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yuehui(张跃辉)

    2002-01-01

    Let A be a quasi-hereditary algebra with a strong exact Borel subalgebra. It is proved that for any standard semisimple subalgebra T there exists an exact Borel subalgebra B of A such that T is a maximal semisimple subalgebra of B. It is shown that the maximal length of flags of exact Borel subalgebras of A is the difference of the radium and the rank of Grothendic group of A plus 2. The number of conjugation-classes of exact Borel subalgebras is 1 if and only if A is basic; the number is 2 if and only if A is semisimple. For all other cases, this number is 0 or no less than 3. Furthermore, it is shown that all the exact Borel subalgebras are idempotent-conjugate to each other, that is, for any exact Borel subalgebras B and C of A, there exists an idempotent e of A, and an invertible element u of A, such that eBe = u-1eCeu.

  13. Mechanical Properties of Nanoworm Assembled by DNA and Nanoparticle Conjugates.

    Science.gov (United States)

    Zhou, Yihua; Sohrabi, Salman; Tan, Jifu; Liu, Yaling

    2016-06-01

    Recently, DNA-nanoparticle conjugates have been widely used as building blocks for assembling complex nanostructures, due to their programmable recognitions, high cellular uptake and enhanced binding capabilities. In this study, a nanoworm structure, which can be applied in fields of drug targeting, image probing and thermal therapies, has been assembled by DNA-nanoparticle conjugates. Subsequently, its mechanical properties have been investigated due to their importance on the structural stability, transport and circulations of the nanoworm. Stiffness and strengths of the nanoworm under different deformation types are studied by coarse-grained molecular dynamics simulations. Effects of temperature, DNA coating density and particle size on mechanical properties of nanoworms are also thoroughly investigated. Results show that both resistance and strength of the nanoworm are the weakest along the axial direction, indicating it is more prone to be ruptured by a stretching force. i addition, DNA strands are found to be more important than nanoparticles in determining mechanical properties of the nanoworm. Moreover, both strength and resistance in regardless of directions are proved to be enhanced by decreasing the temperature, raising the DNA coating density and enlarging the particle size. This study is capable of serving as guidance for designing nanoworms with optimal mechanical strengths for applications. PMID:27427583

  14. SPECIFIC UPTAKE OF MONOCLONAL ANTIBODY-CONJUGATED METHOTREXATE BY HUMAN LYMPHOCYTIC LEUKEMIC B CELLS

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhenping; Yang Chunzheng; Tarunendu Ghose; Jaroslav Kralovec

    1998-01-01

    Objective: To analysis the uptake of free MTX and MTX conjugated to tumor specific monoclonal antibody by target and non-target cells. Methods: The folate antagonist methotrexate (MTX) was conjugated to two monoclonal antibodies (Mab) directed against human chronic lymphocytic leukemia (CLL), Dal B01 and Dal B02, by an active ester method. Both conjugates were more cytotoxic toward the target tumor cell line D10-1than to the non-target cell line MOLT-3, and Dal B02-MTX conjugate was more inhibitory to D10-1 cells than free MTX in a 6 h pulse exposure assay. Results: Drug uptake studies revealed that D10-1 cells took up much more Dal B01 and Dal B02-conjugated MTX than free MTX. The amounts of drug taken up by D10-1 cells incubated with Dal B01 and Dal B02-conjugated MTX were always 3 to 5-fold higher than that taken up by MOLT-3 cells, although the latter took up more drug when incubated with free MTX. Furthermore, tumor cells incubated with Dal B01 or Dal B02-conjugated MTX retained much larger amounts of drug for a prolonged period of time than those incubated with free MTX.Conclusion: The enhanced specific cytotoxicity of Dal B01 and Dal B02-MTX conjugates toward target tumor cells is therefore likely due to (Ⅰ) delivery of larger amounts of MTX to target cells when the drug is conjugated to Mab;(ii) longer retention of Mab-conjugated MTX by target cells; and (iii) slow, prolonged release of MTX from the surface-bound or endocytosed conjugates, rendering them into a sustained release dosage form.

  15. Comparative assay of fluorescent antibody test results among twelve European National Reference Laboratories using various anti-rabies conjugates.

    Science.gov (United States)

    Robardet, E; Andrieu, S; Rasmussen, T Bruun; Dobrostana, M; Horton, D L; Hostnik, P; Jaceviciene, I; Juhasz, T; Müller, T; Mutinelli, F; Servat, A; Smreczak, M; Vanek, E; Vázquez-Morón, S; Cliquet, F

    2013-07-01

    Twelve National Reference Laboratories (NRLs) for rabies have undertaken a comparative assay to assess the comparison of fluorescent antibody test (FAT) results using five coded commercial anti-rabies conjugates (Biorad, Bioveta, Fujirebio, Millipore, and SIFIN conjugates). Homogenized positive brain tissues infected with various lyssavirus species as well as negative samples were analyzed blindly using a standardized FAT procedure. Conjugates B, C, D, and E were found to be significantly more effective than conjugate A for GS7 (French RABV) diluted samples (1/8 and 1/100) while the frequency of concordant results of conjugates C and D differ significantly from conjugates A, B and E for CVS 27. For detection of EBLV-1 strains, conjugates C and D also presented a significantly lower frequency of discordant results compared to conjugates A, B and E. Conjugates B, C and D were found to be significantly more effective than conjugates E and A for EBLV-2 and ABLV samples. In view of these results, conjugates C and D set themselves apart from the others and appeared as the most effective of this 5-panel conjugates. This study clearly demonstrates that the variability of conjugates used by National Reference Laboratories can potentially lead to discordant results and influence assay sensitivity. In case of false negative results this could have a dramatic impact if the animal under investigation is responsible for human exposure. To avoid such situations, confirmatory tests should be implemented.

  16. Conjugation, number of Dewar resonance structures (DSs) in homologous polyzethrene and related conjugated polycyclic hydrocarbon series, and kinked versus straight

    Science.gov (United States)

    Dias, Jerry Ray

    2015-11-01

    Kinked polyzethrenes are more stable than linear polyzethrenes making them better candidates as materials for organic electronic devices (e.g., organic field effect transistors, nonlinear optics, and semiconductors) because of their greater singlet biradical properties. For series of molecules constructed by successive attachment of a given aufbau unit, we are able to derive analytical or recursion expressions relating certain properties. For example, starting with a few known number of Dewar resonance structures (DSs) for such a series, one is often able to derive analytical or recursion expressions for these DS values by our method of successive differences which then lead to either constant or Fibonacci numbers, respectively. The increasing order of π-electronic stability of isomers with the same number of Kekulé structures (K) is determined by their increasing number of DSs. Kinked polycyclic conjugated polyenes with a single classical structure (i.e., K = 1) are more conjugated and stable than their straight polycyclic isomers with a single classical structure.

  17. NIR photoregulated chemo- and photodynamic cancer therapy based on conjugated polyelectrolyte-drug conjugate encapsulated upconversion nanoparticles

    Science.gov (United States)

    Yuan, Youyong; Min, Yuanzeng; Hu, Qinglian; Xing, Bengang; Liu, Bin

    2014-09-01

    The design of nanoplatforms with target recognition and near-infrared (NIR) laser photoregulated chemo- and photodynamic therapy is highly desirable but remains challenging. In this work, we have developed such a system by taking advantage of a conjugated polyelectrolyte (CPE)-drug conjugate and upconversion nanoparticles (UCNPs). The poly(ethylene glycol) (PEG) grafted CPE not only serves as a polymer matrix for UCNP encapsulation, but also as a fluorescent imaging agent, a photosensitizer as well as a carrier for chemotherapeutic drug doxorubicin (DOX) through a UV-cleavable ortho-nitrobenzyl (NB) linker. Upon 980 nm laser irradiation, the UCNPs emit UV and visible light. The up-converted UV light is utilized for controlled drug release through the photocleavage of the ortho-nitrobenzyl linker, while the up-converted visible light is used to initiate the polymer photosensitizer to produce reactive oxygen species (ROS) for photodynamic therapy. The NIR photo-regulated UCNP@CPE-DOX showed high efficiency of ROS generation and controlled drug release in cancer cells upon single laser irradiation. In addition, the combination therapy showed enhanced inhibition of U87-MG cell growth as compared to sole treatments. As two light sources with different wavelengths are always needed for traditional photodynamic therapy and photoregulated drug release, the adoption of UCNPs as an NIR light switch is highly beneficial to combined chemo- and photodynamic therapy with enhanced therapeutic effects.

  18. Conjugation behaviours of CdTe quantum dots and antibody by a novel immunochromatographic method.

    Science.gov (United States)

    Wang, Y; Bai, Y; Wei, X

    2011-03-01

    Three water-soluble CdTe quantum dots (QDs) (green-emitting, yellow-emitting and red-emitting) were synthesised for different refluxing time with 3-mercaptopropionic acid (MPA) as stabiliser. Then the red-emitting CdTe QDs and mouse immunoglobulin G (IgG) were taken as the representative to study the conjugation behaviour of QDs and antibody by a novel immunochromatographic method. After comparing with several methods, that is, direct conjugation, 1-ethyl-3(3-dimethylaminopropyl) carbodiimides hydrochloride (EDC)-mediated conjugation, N-hydroxysuccinimide (NHS)-mediated conjugation, EDC/NHS-mediated conjugation by immunochromatographic strips, EDC and NHS were selected together as coupling agents to conjugate QDs with antibody efficiently. Finally, the K562 leukaemia cells were incubated with the EDC/NHS-mediated conjugates to evaluate the performance in practical application, and the result from fluorescence images showed that it was successfully applied to label cells. The immunochromatographic strip was a superior method to study the conjugation of the fluorophore and antibody. PMID:21241157

  19. Novel curcumin diclofenac conjugate enhanced curcumin bioavailability and efficacy in streptococcal cell wall-induced arthritis

    Directory of Open Access Journals (Sweden)

    S K Jain

    2014-01-01

    Full Text Available Curcumin-diclofenac conjugate as been synthesized by esterification of phenolic group of curcumin with the acid moiety of diclofenac, and characterized by mass spectrometry, NMR, FTIR, DSC, thermogravimetric analysis and X-ray diffraction analysis. The relative solubility of curcumin-diclofenac conjugate, curcumin and diclofenac; stability of curcumin-diclofenac conjugate in intestinal extract; permeability study of curcumin-diclofenac conjugate using the everted rat intestinal sac method; stability of curcumin-diclofenac conjugate in gastrointestinal fluids and in vitro efficacy have been evaluated. In vivo bioavailability of curcumin-diclofenac conjugate and curcumin in Sprague-Dawley rats, and antiarthritic activity of curcumin-diclofenac conjugate, curcumin and diclofenac in modified streptococcal cell wall-induced arthritis model in Balb/c mice to mimic rheumatoid arthritis in humans have also been studied. In all of the above studies, curcumin-diclofenac conjugate exhibited enhanced stability as compared to curcumin; its activity was twice that of diclofenac in inhibiting thermal protein denaturation taken as a measure of in vitro antiinflammatory activity; it enhanced the bioavailability of curcumin by more than five folds, and significantly (P<0.01 alleviated the symptoms of arthritis in streptococcal cell wall-induced arthritis model as compared to both diclofenac and curcumin.

  20. A Scanning Hologram Recorded by Phase Conjugate Property of Nonlinear Crystals

    DEFF Research Database (Denmark)

    Zi-Liang, Ping; Dalsgaard, Erik

    1996-01-01

    A methode of recording a scanning hologram with phase conjugate property of nonlinear crystal is provided. The principle of recording, setup and experiments are given.......A methode of recording a scanning hologram with phase conjugate property of nonlinear crystal is provided. The principle of recording, setup and experiments are given....

  1. Invasive Pneumococcal Disease 3 Years after Introduction of 10-Valent Pneumococcal Conjugate Vaccine, the Netherlands

    OpenAIRE

    Knol, Mirjam J.; Wagenvoort, Gertjan H.J.; Sanders, Elisabeth A. M.; Elberse, Karin; Vlaminckx, Bart J.; Hester E. de Melker; van der Ende, Arie

    2015-01-01

    Three years after a 7-valent pneumococcal conjugate vaccine was replaced by a 10-valent pneumococcal conjugate vaccine in the Netherlands, we observed a decrease in incidence of invasive pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 5, and 7F. Our data do not support or exclude cross-protection against serotype 19A.

  2. Anti-CD163-dexamethasone conjugate inhibits the acute phase response to lipopolysaccharide in rats

    DEFF Research Database (Denmark)

    Thomsen, Karen Louise; Møller, Holger Jon; Graversen, Jonas Heilskov;

    2016-01-01

    AIM: To study the effect of a new anti-CD163-dexamethasone conjugate targeting activated macrophages on the hepatic acute phase response in rats. METHODS: Wistar rats were injected intravenous with either the CD163 targeted dexamethasone-conjugate (0.02 mg/kg) or free dexamethasone (0.02 or 1 mg/...

  3. Functional properties of nisin–carbohydrate conjugates formed by radiation induced Maillard reaction

    International Nuclear Information System (INIS)

    Nisin–carbohydrate conjugates were prepared by irradiating nisin either with glucose or dextran. Increase in browning and formation of intermediate products was observed with a concomitant decrease in free amino and reducing sugar groups indicating occurrence of the Maillard reaction catalyzed by irradiation. Nisin–carbohydrate conjugates showed a broad spectrum antibacterial activity against Gram negative bacteria (Escherichia coli, Pseudomonas fluorescence) as well as Gram positive bacteria (Staphylococcus aureus, Bacillus cereus). Results of antioxidant assays, including that of DPPH radical-scavenging activity and reducing power, showed that the nisin–dextran conjugates possessed better antioxidant potential than nisin–glucose conjugate. These results suggested that it was possible to enhance the functional properties of nisin by preparing radiation induced conjugates suitable for application in food industry. - Highlights: ► Nisin–carbohydrate conjugates were prepared using radiation induced Maillard reaction. ► Conjugation of nisin with dextran/glucose resulted in improvement of antibacterial spectrum. ► Conjugates of nisin with dextran/glucose had significant radical scavenging activity.

  4. Physicochemical properties of β-carotene emulsions stabilized by chlorogenic acid-lactoferrin-glucose/polydextrose conjugates.

    Science.gov (United States)

    Liu, Fuguo; Wang, Di; Xu, Honggao; Sun, Cuixia; Gao, Yanxiang

    2016-04-01

    In this study, the influence of chlorogenic acid (CA)-lactoferrin (LF)-glucose (Glc) conjugate and CA-LF-polydextrose (PD) conjugate on the physicochemical characteristics of β-carotene emulsions was investigated. Novel emulsifiers were formed during Maillard reaction between CA-LF conjugate and Glc/PD. The physicochemical properties of β-carotene emulsions were characterized by droplet size, ζ-potential, rheological behavior, transmission changes during centrifugal sedimentation and β-carotene degradation. Results showed that the covalent attachment of Glc or PD to CA-LF conjugate effectively increased the hydrophilicity of the oil droplets surfaces and strengthened the steric repulsion between the oil droplets. Glucose was better than polydextrose for the conjugation with CA-LF conjugate to stabilize β-carotene emulsions. In comparison with LF and CA-LF-Glc/PD mixtures, CA-LF-Glc/PD ternary conjugates exhibited better emulsifying properties and improved physical stability of β-carotene emulsions during the freeze-thaw treatment. In addition, CA-LF-Glc/PD conjugates significantly enhanced chemical stability of β-carotene in the emulsions against ultraviolet light exposure. PMID:26593499

  5. Sequence-selective DNA binding with cell-permeable oligoguanidinium-peptide conjugates.

    Science.gov (United States)

    Mosquera, Jesús; Sánchez, Mateo I; Valero, Julián; de Mendoza, Javier; Vázquez, M Eugenio; Mascareñas, José L

    2015-03-21

    Conjugation of a short peptide fragment from a bZIP protein to an oligoguanidinium tail results in a DNA-binding miniprotein that selectively interacts with composite sequences containing the peptide-binding site next to an A/T-rich tract. In addition to stabilizing the complex with the target DNA, the oligoguanidinium unit also endows the conjugate with cell internalization properties.

  6. Purification and Characterization of Conjugated Bile Salt Hydrolase from Bifidobacterium longum BB536

    OpenAIRE

    Grill, J; Schneider, F.; Crociani, J.; Ballongue, J.

    1995-01-01

    Bifidobacterium species deconjugate taurocholic, taurodeoxycholic, taurochenodeoxycholic, glycocholic, glycodeoxycholic, and glycochenodeoxycholic acids. The enzyme level increases in the growth phase. No increase in activity is observed for the cytoplasmic enzyme after addition of conjugated bile acids to a stationary-phase culture. Conjugated bile salt hydrolase (BSH) was purified from Bifidobacterium longum BB536. Its apparent molecular mass in denaturing polyacrylamide gel electrophoresis...

  7. Thin Films Formed from Conjugated Polymers with Ionic, Water-Soluble Backbones

    NARCIS (Netherlands)

    Voortman, Thomas P; Chiechi, Ryan C

    2015-01-01

    This paper compares the morphologies of films of conjugated polymers in which the backbone (main chain) and pendant groups are varied between ionic/hydrophilic and aliphatic/hydrophobic. We observe that conjugated polymers in which the pendant groups and backbone are matched, either ionic-ionic or h

  8. Tales of conjugation and sex pheromones: A plasmid and enterococcal odyssey

    OpenAIRE

    Clewell, Don B

    2011-01-01

    This review covers highlights of the author's experience becoming and working as a plasmid biologist. The account chronicles a progression from studies of ColE1 DNA in Escherichia coli to Gram-positive bacteria with an emphasis on conjugation in enterococci. It deals with gene amplification, conjugative transposons and sex pheromones in the context of bacterial antibiotic resistance.

  9. Tales of conjugation and sex pheromones: A plasmid and enterococcal odyssey.

    Science.gov (United States)

    Clewell, Don B

    2011-05-01

    This review covers highlights of the author's experience becoming and working as a plasmid biologist. The account chronicles a progression from studies of ColE1 DNA in Escherichia coli to Gram-positive bacteria with an emphasis on conjugation in enterococci. It deals with gene amplification, conjugative transposons and sex pheromones in the context of bacterial antibiotic resistance. PMID:22016844

  10. Observation of Image Transfer and Phase Conjugation in Stimulated Down-Conversion

    CERN Document Server

    Souto-Ribeiro, P H; Almeida, M P; Huguenin, J A; Dos Santos, B C; Khoury, A Z

    2001-01-01

    We observe experimentally the transfer of angular spectrum and image formation in the process of stimulated parametric down-conversion. Images and interference patterns can be transferred either from the pump or the auxiliary laser beams to the stimulated down-converted one. The stimulated field propagates as the complex conjugate of the auxiliary laser. The phase conjugation is observed through intensity pattern measurements.

  11. Site-Specific Zwitterionic Polymer Conjugates of a Protein Have Long Plasma Circulation.

    Science.gov (United States)

    Bhattacharjee, Somnath; Liu, Wenge; Wang, Wei-Han; Weitzhandler, Isaac; Li, Xinghai; Qi, Yizhi; Liu, Jinyao; Pang, Yan; Hunt, Donald F; Chilkoti, Ashutosh

    2015-11-01

    Many proteins suffer from suboptimal pharmacokinetics (PK) that limit their utility as drugs. The efficient synthesis of polymer conjugates of protein drugs with tunable PK to optimize their in vivo efficacy is hence critical. We report here the first study of the in vivo behavior of a site-specific conjugate of a zwitterionic polymer and a protein. To synthesize the conjugate, we first installed an initiator for atom-transfer radical polymerization (ATRP) at the N terminus of myoglobin (Mb-N-Br). Subsequently, in situ ATRP was carried out in aqueous buffer to grow an amine-functionalized polymer from Mb-N-Br. The cationic polymer was further derivatized to two zwitterionic polymers by treating the amine groups of the cationic polymer with iodoacetic acid to obtain poly(carboxybetaine methacrylate) with a one-carbon spacer (PCBMA; C1 ), and sequentially with 3-iodopropionic acid and iodoacetic acid to obtain PCBMA(mix) with a mixture of C1 and C2 spacers. The Mb-N-PCBMA polymer conjugates had a longer in vivo plasma half-life than a PEG-like comb polymer conjugate of similar molecular weights (MW). The structure of the zwitterion plays a role in controlling the in vivo behavior of the conjugate, as the PCBMA conjugate with a C1 spacer had significantly longer plasma circulation than the conjugate with a mixture of C1 and C2 spacers.

  12. In vivo quantification of renal sulfate and glucuronide conjugation in the chicken

    International Nuclear Information System (INIS)

    A Specific Activity Difference Ratio (SADR) technique was developed to quantify simultaneously the in vivo sulfate and glucuronide conjugation in the kidneys. In man and the chicken, p-nitrophenol (PNP) is excreted almost entirely in the urine, where it is present as the sulfate and glucuronide conjugates. Measurements of the SADR's for p-nitro[14C]phenyl sulfate (14C-PNPS) and p-nitro[14C] phenyl glucuronide (14C-PNPG) in the fasted, unanesthetized chicken during the infusion of 14C-PNP at a rate of 100 nmol/min/kg, revealed that a minimum of 38% of the conjugation of PNP occurred in the kidneys. 14C-PNPS accounted for virtually all of the nephrogenic conjugates. Catechol, which is known to compete with PNP for renal conjugation, was used to test the validity of the SADR technique. During catechol infusion into the renal portal circulation of one kidney, the renal tubular conjugation and excretory transport of 14C-PNP decreased essentially to zero, as did the SADR for 14C-PNP conjugates, suggesting that the SADR technique is a valid indicator of in vivo renal conjugation

  13. 关于Banach共轭算子和Hilbert共轭算子的讨论%Discussion on Banach conjugate operator and Hilbert conjugate operator

    Institute of Scientific and Technical Information of China (English)

    杨纪华; 李艳秋

    2014-01-01

    Banach conjugate operator and Hilbert conjugate operator are two very important concepts in functional analysis. Hilbert space is a special Banach space,but the conjugate operator in Hilbert space does not follow the definition of conjugate operator in Banach space,and thevast majority textbooks don′t explain the reasons for this definition.Described the reason why conjugate operator in Hilbert space does not follow the definition of conjugate operator in Banach space,and discussed the relationship between the two operators.%Banach共轭算子和Hilbert共轭算子是泛函分析中两个非常重要的概念.Hilbert 空间是特殊的Banach空间,但Hilbert空间上的共轭算子没有沿用Banach空间上共轭算子的定义,并且绝大数教材都没有说明这样定义的原因.阐述了Hilbert空间上的共轭算子没有沿用Banach空间上共轭算子定义的原因,并讨论Hilbert空间中这两种算子的关系.

  14. Enzyme-Regulated Supramolecular Assemblies of Cholesterol Conjugates against Drug-Resistant Ovarian Cancer Cells.

    Science.gov (United States)

    Wang, Huaimin; Feng, Zhaoqianqi; Wu, Dongdong; Fritzsching, Keith J; Rigney, Mike; Zhou, Jie; Jiang, Yujie; Schmidt-Rohr, Klaus; Xu, Bing

    2016-08-31

    We report that phosphotyrosine-cholesterol conjugates effectively and selectively kill cancer cells, including platinum-resistant ovarian cancer cells. The conjugate increases the degree of noncovalent oligomerization upon enzymatic dephosphorylation in aqueous buffer. This enzymatic conversion also results in the assembly of the cholesterol conjugates inside and outside cells and leads to cell death. Preliminary mechanistic studies suggest that the formed assemblies of the conjugates not only interact with actin filaments and microtubules but also affect lipid rafts. As the first report of multifaceted supramolecular assemblies of cholesterol conjugates against cancer cells, this work illustrates the integration of enzyme catalysis and self-assembly of essential biological small molecules on and inside cancer cells as a promising strategy for developing multifunctional therapeutics to treat drug-resistant cancers. PMID:27529637

  15. Optimization with numerical simulations of the conjugate altitudes of deformable mirrors in an MCAO system

    CERN Document Server

    Femenia, B

    2003-01-01

    This article reports on the results of simulations conducted to assess the performance of a modal Multi-Conjugate Adaptive Optics (MCAO) system on a 10m telescope with one Deformable Mirror (DM) conjugated to the telescope pupil and a second DM conjugated at a certain altitude above the pupil. The main goal of these simulations is to study the dependence of MCAO performance upon the altitude of the high-altitude conjugated DM and thereby determine its optimal conjugation. The performance is also studied with respect to the geometry of the Guide Star constellation when using constellations of Natural Guide Stars (NGS), which are rare, or constellations of Laser Guide Stars (LGS) which would allow large sky coverage.

  16. Functional properties of nisin-carbohydrate conjugates formed by radiation induced Maillard reaction

    Science.gov (United States)

    Muppalla, Shobita R.; Sonavale, Rahul; Chawla, Surinder P.; Sharma, Arun

    2012-12-01

    Nisin-carbohydrate conjugates were prepared by irradiating nisin either with glucose or dextran. Increase in browning and formation of intermediate products was observed with a concomitant decrease in free amino and reducing sugar groups indicating occurrence of the Maillard reaction catalyzed by irradiation. Nisin-carbohydrate conjugates showed a broad spectrum antibacterial activity against Gram negative bacteria (Escherichia coli, Pseudomonas fluorescence) as well as Gram positive bacteria (Staphylococcus aureus, Bacillus cereus). Results of antioxidant assays, including that of DPPH radical-scavenging activity and reducing power, showed that the nisin-dextran conjugates possessed better antioxidant potential than nisin-glucose conjugate. These results suggested that it was possible to enhance the functional properties of nisin by preparing radiation induced conjugates suitable for application in food industry.

  17. Preparation and characterization of conjugated polyamidoamine-MPEG-methotrexate for potential drug delivery system

    Science.gov (United States)

    Mohd Sabri, Siti Noorzidah bt; Abu, Norhidayah; Mastor, Azreena; Hisham, Siti Farhana; Noorsal, Kartini

    2012-07-01

    Star polymers have unique characteristics due to their well-defined size and tailor ability which makes these polymers attractive candidates as carriers in drug delivery system applications. This work focuses on attaching a drug to the star polymer (polyamidoamine). The conjugation of polyamidoamine (PAMAM, generation 4) with methotrexate (MTX) (model drug) was studied in which monomethyl polyethylene glycol (MPEG) was used as a linker to reduce the toxicity of dendrimer. Conjugation starts with attaching the drug to the linker and followed by further conjugation with the polyamidoamine (PAMAM) dendrimer. The conjugation of PAMAM-PEG-MTX was confirmed through UV-Vis, FTIR, 1H NMR and DSC. The loading capacities and release profile of this conjugate were determined using 1H NMR and UV spectrometer.

  18. Preparation of thermocleavable conjugates based on ansamitocin and superparamagnetic nanostructured particles by a chemobiosynthetic approach.

    Science.gov (United States)

    Mancuso, Lena; Knobloch, Tobias; Buchholz, Jessica; Hartwig, Jan; Möller, Lena; Seidel, Katja; Collisi, Wera; Sasse, Florenz; Kirschning, Andreas

    2014-12-22

    A combination of mutasynthesis, precursor-directed biosynthesis and semisynthesis provides access to new ansamitocin derivatives including new nanostructured particle-drug conjugates. These conjugates are based on the toxin ansamitocin and superparamagnetic iron oxide-silica core shell particles. New ansamitocin derivatives that are functionalized either with alkynyl- or azido groups in the ester side chain at C-3 are attached to nanostructured iron oxide core-silica shell particles. Upon exposure to an oscillating electromagnetic field these conjugates heat up and the ansamitocin derivatives are released by a retro-Diels-Alder reaction. For example, one ansamitocin derivative exerts strong antiproliferative activity against various cancer cell lines in the lower nanomolar range while the corresponding nanostructured particle-drug conjugate is not toxic. Therefore, these new conjugates can serve as dormant toxins that can be employed simultaneously in hyperthermia and chemotherapy when external inductive heating is applied. PMID:25346489

  19. Diketopyrrolopyrrole-based Conjugated Polymers Bearing Branched Oligo(Ethylene Glycol) Side Chains for Photovoltaic Devices.

    Science.gov (United States)

    Chen, Xingxing; Zhang, Zijian; Ding, Zicheng; Liu, Jun; Wang, Lixiang

    2016-08-22

    Conjugated polymers are essential for solution-processable organic opto-electronic devices. In contrast to the great efforts on developing new conjugated polymer backbones, research on developing side chains is rare. Herein, we report branched oligo(ethylene glycol) (OEG) as side chains of conjugated polymers. Compared with typical alkyl side chains, branched OEG side chains endowed the resulting conjugated polymers with a smaller π-π stacking distance, higher hole mobility, smaller optical band gap, higher dielectric constant, and larger surface energy. Moreover, the conjugated polymers with branched OEG side chains exhibited outstanding photovoltaic performance in polymer solar cells. A power conversion efficiency of 5.37 % with near-infrared photoresponse was demonstrated and the device performance could be insensitive to the active layer thickness.

  20. Comparative assay of fluorescent antibody test results among twelve European National Reference Laboratories using various anti-rabies conjugates

    DEFF Research Database (Denmark)

    Robardet, E.; Andrieu, S.; Rasmussen, Thomas Bruun;

    2013-01-01

    Twelve National Reference Laboratories (NRLs) for rabies have undertaken a comparative assay to assess the comparison of fluorescent antibody test (FAT) results using five coded commercial anti-rabies conjugates (Biorad, Bioveta, Fujirebio, Millipore, and SIFIN conjugates). Homogenized positive...

  1. A strategy to enhance the binding affinity of fluorophore-aptamer pairs for RNA tagging with neomycin conjugation.

    Science.gov (United States)

    Jeon, Jongho; Lee, Kyung Hyun; Rao, Jianghong

    2012-10-14

    Fluorogenic sulforhodamine-neomycin conjugates have been designed and synthesized for RNA tagging. Conjugates were fluorescently activated by binding to RNA aptamers and exhibited greater than 250-400 fold enhancement in binding affinity relative to corresponding unconjugated fluorophores.

  2. [The metabolism and conjugation of estrogens in the human fetus].

    Science.gov (United States)

    Tsukamoto, K

    1984-09-20

    Although several studies have been reported on the synthesis of steroids in the fetus, the metabolism and conjugation of estrogens in the fetus is not completely known. In this study serum levels of estetrol (E4), estetrol glucosiduronate (E4-G), estriol (E3) and estriol-16-glucosiduronate (E3-16-G) were measured by R.I.A. in maternal peripheral vein blood (MPV), umbilical artery blood (UA) and umbilical vein blood (UV) at delivery. The same steroids were also measured in various fetal organs (liver, kidney, intestine, adrenal, lung and placenta) in the second-trimester. After 4-14C-E2, 4-14C-E3 and 6, 9 (n)-3H-E4 were incubated with homogenates of various human fetal organs, the metabolites were analyzed with an authentic sample. 15, 15-D2-estradiol-17 beta (d2-E2) was incubated with human second-trimester fetal liver and the metabolites were analyzed with GC-MS. It was concluded that: 1) E3-16-G was higher in UA and UV than in MPV, suggesting active glucosiduronation in the fetus. 2) Higher levels of E4 and E4-G in UA and UV than in MPV suggest the production of E3 and E3-16-G in the fetus. 3) Levels of E4 and E4-G were higher than those of E3 and E3-16-G in various fetal organs in the second-trimester. 4) E4 and E4-G were especially high in fetal liver and intestine, and E3 and E3-16-G were high in fetal kidney, liver and intestine. 5) The level of E3-16-G was higher than that of E3 in these organs. 6) The second-trimester fetal liver conjugated E2, E3 and E4 to each glucosiduronate. 7) The second-trimester fetal kidney conjugated E2 and E4 to each sulfate, but E3 to E3-16-G. 8) 15-Hydroxylation of d2-E2 was demonstrated in the incubation with homogenate of second human fetal liver. 9) The active glucosiduronation of E3 in the fetus was thought to inactivate a large amount of E3 transported from the placenta. PMID:6519315

  3. Incorporating distant sequence features and radial basis function networks to identify ubiquitin conjugation sites.

    Science.gov (United States)

    Lee, Tzong-Yi; Chen, Shu-An; Hung, Hsin-Yi; Ou, Yu-Yen

    2011-03-09

    Ubiquitin (Ub) is a small protein that consists of 76 amino acids about 8.5 kDa. In ubiquitin conjugation, the ubiquitin is majorly conjugated on the lysine residue of protein by Ub-ligating (E3) enzymes. Three major enzymes participate in ubiquitin conjugation. They are E1, E2 and E3 which are responsible for activating, conjugating and ligating ubiquitin, respectively. Ubiquitin conjugation in eukaryotes is an important mechanism of the proteasome-mediated degradation of a protein and regulating the activity of transcription factors. Motivated by the importance of ubiquitin conjugation in biological processes, this investigation develops a method, UbSite, which uses utilizes an efficient radial basis function (RBF) network to identify protein ubiquitin conjugation (ubiquitylation) sites. This work not only investigates the amino acid composition but also the structural characteristics, physicochemical properties, and evolutionary information of amino acids around ubiquitylation (Ub) sites. With reference to the pathway of ubiquitin conjugation, the substrate sites for E3 recognition, which are distant from ubiquitylation sites, are investigated. The measurement of F-score in a large window size (-20∼+20) revealed a statistically significant amino acid composition and position-specific scoring matrix (evolutionary information), which are mainly located distant from Ub sites. The distant information can be used effectively to differentiate Ub sites from non-Ub sites. As determined by five-fold cross-validation, the model that was trained using the combination of amino acid composition and evolutionary information performs best in identifying ubiquitin conjugation sites. The prediction sensitivity, specificity, and accuracy are 65.5%, 74.8%, and 74.5%, respectively. Although the amino acid sequences around the ubiquitin conjugation sites do not contain conserved motifs, the cross-validation result indicates that the integration of distant sequence features of Ub

  4. Incorporating distant sequence features and radial basis function networks to identify ubiquitin conjugation sites.

    Directory of Open Access Journals (Sweden)

    Tzong-Yi Lee

    Full Text Available Ubiquitin (Ub is a small protein that consists of 76 amino acids about 8.5 kDa. In ubiquitin conjugation, the ubiquitin is majorly conjugated on the lysine residue of protein by Ub-ligating (E3 enzymes. Three major enzymes participate in ubiquitin conjugation. They are E1, E2 and E3 which are responsible for activating, conjugating and ligating ubiquitin, respectively. Ubiquitin conjugation in eukaryotes is an important mechanism of the proteasome-mediated degradation of a protein and regulating the activity of transcription factors. Motivated by the importance of ubiquitin conjugation in biological processes, this investigation develops a method, UbSite, which uses utilizes an efficient radial basis function (RBF network to identify protein ubiquitin conjugation (ubiquitylation sites. This work not only investigates the amino acid composition but also the structural characteristics, physicochemical properties, and evolutionary information of amino acids around ubiquitylation (Ub sites. With reference to the pathway of ubiquitin conjugation, the substrate sites for E3 recognition, which are distant from ubiquitylation sites, are investigated. The measurement of F-score in a large window size (-20∼+20 revealed a statistically significant amino acid composition and position-specific scoring matrix (evolutionary information, which are mainly located distant from Ub sites. The distant information can be used effectively to differentiate Ub sites from non-Ub sites. As determined by five-fold cross-validation, the model that was trained using the combination of amino acid composition and evolutionary information performs best in identifying ubiquitin conjugation sites. The prediction sensitivity, specificity, and accuracy are 65.5%, 74.8%, and 74.5%, respectively. Although the amino acid sequences around the ubiquitin conjugation sites do not contain conserved motifs, the cross-validation result indicates that the integration of distant sequence

  5. Structure Tuning of Cationic Oligospermine-siRNA Conjugates for Carrier-Free Gene Silencing.

    Science.gov (United States)

    Nothisen, Marc; Bagilet, Jérémy; Behr, Jean-Paul; Remy, Jean-Serge; Kotera, Mitsuharu

    2016-08-01

    Oligospermine-siRNA conjugates are able to induce efficient luciferase gene silencing upon carrier-free transfection. These conjugates are readily accessible by a versatile automated chemistry that we developed using a DMT-spermine phosphoramidite reagent. In this article, we used this chemistry to study a wide range of structural modifications of the oligospermine-siRNA conjugates, i.e., variation of conjugate positions and introduction of chemical modifications to increase nuclease resistance. At first we examined gene silencing activity of a series of siRNA-tris(spermine) conjugates with and without chemical modifications in standard carrier assisted conditions. The three spermine units attached at one of the two ends of the sense strand or at the 3'-end of the antisense strand are compatible with gene silencing activity whereas attachment of spermine units at the 5'-end of the antisense strand abolished the activity. 2'-O-Methylated nucleotides introduced in the sense strand are compatible while not in the antisense strand. Thiophosphate links could be used without activity loss at the 3'-end of both strands and at the 5'-end of the sense strand to conjugate oligospermine. Consequently a series of oligospermine-siRNA conjugates containing 15 to 45 spermines units in various configurations were chosen, prepared, and examined in carrier-free conditions. Attachment of 30 spermine units singly at the 5'-end of the sense strand provides the most potent carrier-free siRNA. Longevity of luciferase gene silencing was studied using oligospermine-siRNA conjugates. Five day long efficiency with more than 80% gene expression knockdown was observed upon transfection without vector. Oligospermine-siRNA conjugates targeting cell-constitutive natural lamin A/C gene were prepared. Efficient gene silencing was observed upon carrier-free transfection of siRNA conjugates containing 20 or 30 spermine residues grafted at the 5'-end of the sense strand. PMID:27398779

  6. Characterization and evolution of a family of integrative and potentially conjugative or mobilizable elements from Streptococcus thermophilus

    OpenAIRE

    Pavlovic, Guillaume; Burrus, Vincent; Toulmay, Alexandre; Choulet, Frédéric; Decaris, Bernard; Guédon, Gérard

    2004-01-01

    International audience The integrative and conjugative elements (ICEs) excise by site-specific recombination, self-transfer the resulting circular form by conjugation and integrate into the genome of the recipient bacterium. The 34.7-kb element from Streptococcus thermophilus CNRZ368, ICESt1, excises and integrates by site-specific recombination. This element also possesses a conjugation module distantly related to that of the conjugative transposon Tn916 from Enterococcus faecalis. Theref...

  7. Biodegradable multiblock poly(N-2-hydroxypropyl)methacrylamide gemcitabine and paclitaxel conjugates for ovarian cancer cell combination treatment

    OpenAIRE

    Larson, Nate; Yang, Jiyuan; Ray, Abhijit; Cheney, Darwin L.; Ghandehari, Hamidreza; Kopeček, Jindřich

    2013-01-01

    The synthesis, characterization, and in vitro evaluation of a combination delivery of multiblock poly(N-2-hydroxypropyl)methacrylamide (HPMA), gemcitabine (GEM) and paclitaxel (PTX) conjugates is described in this study. Multiblock copolymer conjugates of a large molecular weight (Mw > 200 kDa) were studied and compared to traditional, small molecular weight (Mw < 45 kDa) conjugates. Stability of the conjugates in different pH was assessed, and their cytotoxicity in combination toward A2780 h...

  8. Hydrophobic conjugated microporous polymers for sorption of human serum albumin

    Science.gov (United States)

    Zheng, Chunli; Du, Miaomiao; Feng, Shanshan; Sun, Hanxue; Li, An; He, Chi; Zhang, TianCheng; Wang, Qiaorui; Wei, Wei

    2016-02-01

    This paper investigated the sorption of human serum albumin (HSA) from water by three kinds of conjugated microporous polymers (CMPs) with surface hydrophobicity and intrinsic porosity. It was found that the three CMPs captured HSA with fast sorption kinetics and good working capacity. Equilibrium was obtained at 80 min for all the tests, and the maximum sorption quantity (qm) ranged from 0.07 to 0.14 mg/mg. With the increase in the particle external surface area of the CMPs, a greater extent of HSA sorption was achieved. Moreover, promoting the dispersion of CMPs in HSA aqueous solution was also beneficial to the extraction. Attenuated Total Reflection Fourier Transform Infrared spectroscopy verified the interactions between the CMPs and the Nsbnd H, Cdbnd O, and Csbnd N groups of HSA. This paper might provide fundamental guidance for the practical application of CMPs to proteins separation and recovery.

  9. Temperature dependence of charge transport in conjugated single molecule junctions

    Science.gov (United States)

    Huisman, Eek; Kamenetska, Masha; Venkataraman, Latha

    2011-03-01

    Over the last decade, the break junction technique using a scanning tunneling microscope geometry has proven to be an important tool to understand electron transport through single molecule junctions. Here, we use this technique to probe transport through junctions at temperatures ranging from 5K to 300K. We study three amine-terminated (-NH2) conjugated molecules: a benzene, a biphenyl and a terphenyl derivative. We find that amine groups bind selectively to undercoordinate gold atoms gold all the way down to 5K, yielding single molecule junctions with well-defined conductances. Furthermore, we find that the conductance of a single molecule junction increases with temperature and we present a mechanism for this temperature dependent transport result. Funded by a Rubicon Grant from The Netherlands Organisation for Scientific Research (NWO) and the NSEC program of NSF under grant # CHE-0641523.

  10. Surface Modification of Liposomal Vaccines by Peptide Conjugation

    Directory of Open Access Journals (Sweden)

    Hazra M2

    2011-01-01

    Full Text Available The aim of the present work was to prepare liposomal vaccine formulation by incorporating naked plasmid DNA that can trigger humoral and cell mediated protective immunity against infection. For these cationic lipids like dimyristoyl phosphatidylcholine (DMPC, dioleyl phosphatidyl ethanolamine (DOPE, [1, 2 – dioleyloxy -3-(trimethyl ammonium propane] (DOTAP, were taken in the ratio of 4:2:1 respectively. The liposomal formulations thus prepared were surface modified by peptide conjugation with the help of EDC and NHS. Physical characterization of liposomal formulationswas done by estimating the average size distribution, which gives an average liposomal size of 53.0nm. Concentration of peptide bound liposomes wasestimated by Lowry method which entails that bound protein concentration was 30.5 µg/ml.

  11. A conjugate thermo-electric model for a composite medium.

    Science.gov (United States)

    Chávez, Oscar; Godínez, Francisco A; Beltrán, Alberto; García, Armando; Zenit, Roberto

    2014-01-01

    Electrical transmission signals have been used for decades to characterize the internal structure of composite materials. We theoretically analyze the transmission of an electrical signal through a composite material which consists of two phases with different chemical compositions. We assume that the temperature of the biphasic system increases as a result of Joule heating and its electrical resistivity varies linearly with temperature; this last consideration leads to simultaneously study the electrical and thermal effects. We propose a nonlinear conjugate thermo-electric model, which is solved numerically to obtain the current density and temperature profiles for each phase. We study the effect of frequency, resistivities and thermal conductivities on the current density and temperature. We validate the prediction of the model with comparisons with experimental data obtained from rock characterization tests. PMID:24867618

  12. A conjugate thermo-electric model for a composite medium.

    Directory of Open Access Journals (Sweden)

    Oscar Chávez

    Full Text Available Electrical transmission signals have been used for decades to characterize the internal structure of composite materials. We theoretically analyze the transmission of an electrical signal through a composite material which consists of two phases with different chemical compositions. We assume that the temperature of the biphasic system increases as a result of Joule heating and its electrical resistivity varies linearly with temperature; this last consideration leads to simultaneously study the electrical and thermal effects. We propose a nonlinear conjugate thermo-electric model, which is solved numerically to obtain the current density and temperature profiles for each phase. We study the effect of frequency, resistivities and thermal conductivities on the current density and temperature. We validate the prediction of the model with comparisons with experimental data obtained from rock characterization tests.

  13. Conjugative plasmids: Vessels of the communal gene pool

    DEFF Research Database (Denmark)

    Norman, Anders; Hansen, Lars H.; Sørensen, Søren Johannes

    2009-01-01

    Comparative whole-genome analyses have demonstrated that horizontal gene transfer (HGT) provides a significant contribution to prokaryotic genome innovation. The evolution of specific prokaryotes is therefore tightly linked to the environment in which they live and the communal pool of genes...... available within that environment. Here we use the term supergenome to describe the set of all genes that a prokaryotic ‘individual' can draw on within a particular environmental setting. Conjugative plasmids can be considered particularly successful entities within the communal pool, which have enabled HGT...... to the hosts and, potentially, other resident prokaryotes within specific environmental niches. Insight into the evolution of plasmid modules therefore contributes to our knowledge of gene dissemination and evolution within prokaryotic communities. This communal pool provides the prokaryotes with an important...

  14. NUMERICAL APPROACH TO DETERMINING INSTANTANEOUS CONTACT REGION FOR CONJUGATE SURFACES

    Institute of Scientific and Technical Information of China (English)

    WANG Taiyong; LI Jingcai; HE Gaiyun; FAN Shengbo; HAO Yongjiang

    2008-01-01

    According to the defect of traditional method of determining instantaneous contact regions for conjugate surfaces, a numerical approach to the determination is proposed. A local coordinate system is built by using the surface unit tangent and unit normal at the contact point. Considering that the gap forming the boundary of instantaneous contact region in the direction of the common normal vectors is given, a system of nonlinear equations is built to find the instantaneous contact boundary in local coordinate system, a modified Powell's hybrid algorithm of finite-difference approximation to the Jacobian used to solve the system. The new method simplifies the task of determining instantaneous contact regions without calculating curvature and relative curvature. The validity of the proposed approach is verified by an example of hypoid gears.

  15. Adsorption calorimetry of conjugated organic molecules on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lytken, Ole; Drescher, Hans-Joerg; Bebensee, Fabian; Steinrueck, Hans-Peter; Gottfried, J. Michael [Universitaet Erlangen-Nuernberg, Lehrstuhl fuer Physikalische Chemie II (Germany)

    2011-07-01

    Traditional experimental methods for determining adsorption energies, such as temperature programmed desorption (TPD) and equilibrium adsorption isotherms, rely on desorption. However, on many metal surfaces large conjugated organic molecules, such as PTCDA and pentacene, decompose at elevated temperatures before or simultaneously with desorption. Discussions about relative bond strengths are, therefore, typically based on indirect arguments, such as the height of the adsorbed species above the surface as measured with normal incidence X-ray standing waves (NIXSW) or chemical shifts in spectroscopic techniques such as X-ray photoelectron spectroscopy (XPS). Unlike the more traditional methods, nanojoule adsorption calorimetry does not require desorption of the molecules; instead, the heat of adsorption is measured directly as an adsorption-induced temperature change of the sample. We will describe the construction of such a calorimeter at the Universitaet Erlangen-Nuernberg.

  16. Control of self organization in conjugated polymer fibers.

    Science.gov (United States)

    Chuangchote, Surawut; Fujita, Michiyasu; Sagawa, Takashi; Sakaguchi, Hiroshi; Yoshikawa, Susumu

    2010-11-01

    We propose new strategy to facilitate the fabrication of conjugated polymer fiber with higher oriented structures, which focused on electrospinning of a blend solution of regioregular poly(3-hexylthiophene) (rr-P3HT) and poly(vinyl pyrrolidone) (PVP). SEM observation revealed that the blend system forms homogeneous composite nanofibers. This system exhibits the specific feature of strong interchain contribution of P3HT from UV-vis absorption, fluorescence spectroscopic, XRD, and photoelectron spectrometric (for HOMO levels) investigations. We also demonstrate the removal of the PVP component from the P3HT/PVP composite fibers through the selective extraction and such strong interchain stacking of pristine P3HT fiber mat can be remarkably maintained.

  17. Analysis of Peptides and Conjugates by Amino Acid Analysis

    DEFF Research Database (Denmark)

    Højrup, Peter

    2015-01-01

    Amino acid analysis is a highly accurate method for characterization of the composition of synthetic peptides. Together with mass spectrometry, it gives a reliable control of peptide quality and quantity before conjugation and immunization.Peptides are hydrolyzed, preferably in gas phase, with 6 M...... HCl at 110 °C for 20-24 h and the resulting amino acids analyzed by ion-exchange chromatography with post-column ninhydrin derivatization. Depending on the hydrolysis conditions, tryptophan is destroyed, and cysteine also, unless derivatized, and the amides, glutamine and asparagine, are deamidated to...... glutamic acid and aspartic acid, respectively. Three different ways of calculating results are suggested, and taking the above limitations into account, a quantitation better than 5 % can usually be obtained....

  18. Fuzzy ta/2 symmetries of straight chain conjugate polyene molecules

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    On the basis of our recent studies on the molecular fuzzy point group symmetry,we further probe into the more complicated planar one-dimensional fuzzy periodic molecules-straight chain conjugate polyene.Except for the fuzzy translation transformation,the space transformation of the fuzzy screw rotation and the glide plane will be referred to.In addition,other fuzzy point symmetry transformation lain in the space transformation is discussed.Usually there is a correlation between the fuzzy symmetry characterization caused by the transition of the point symmetry elements and by certain space symmetry transformation.For the molecular orbital,the irreducible representation component is analyzed besides the membership function of the fuzzy symmetry transformation.Also,we inquire into the relativity between some molecular property and the fuzzy symmetry characterization.

  19. MILC staggered conjugate gradient performance on Intel KNL

    CERN Document Server

    DeTar, Carleton; Gottlieb, Steven; Jha, Ashish; Kalamkar, Dhiraj; Li, Ruizi; Toussaint, Doug

    2016-01-01

    We review our work done to optimize the staggered conjugate gradient (CG) algorithm in the MILC code for use with the Intel Knights Landing (KNL) architecture. KNL is the second gener- ation Intel Xeon Phi processor. It is capable of massive thread parallelism, data parallelism, and high on-board memory bandwidth and is being adopted in supercomputing centers for scientific research. The CG solver consumes the majority of time in production running, so we have spent most of our effort on it. We compare performance of an MPI+OpenMP baseline version of the MILC code with a version incorporating the QPhiX staggered CG solver, for both one-node and multi-node runs.

  20. Nanoparticles based DNA conjugates for detection of pathogenic microorganisms

    Science.gov (United States)

    Jamdagni, Pragati; Khatri, Poonam; Rana, J. S.

    2016-01-01

    Infectious diseases have been on rise in the recent past. Early diagnosis plays a role as important as proper treatment and prophylaxis. The current practices of detection are time consuming which may result in unnecessary delays in treatment. Advances in nanodiagnostic approaches have been in focus lately. The rising interest and better understanding of nanoparticles have led to opening up of new frontiers in the concerned area. Optical properties of nanoparticles are being exploited to design detection systems that can provide fast, one-step and reliable results. Based on conserved DNA sequences unique to the target organism, the results offer accuracy comparable to conventional tests. Further, visual or spectrophotometric analysis omits the need of costly apparatus for result interpretation. The present review aims at putting together the information on nanoparticles based DNA conjugate systems for detection of pathogenic microorganisms.

  1. Conference report: hot topics in antibody-drug conjugate development.

    Science.gov (United States)

    Thudium, Karen; Bilic, Sanela

    2013-12-01

    American Association of Pharmaceutical Scientists National Biotechnology Conference Sheraton San Diego Hotel and Marina, San Diego, CA, USA, 19-23 May 2013 The National Biotechnology Conference, is a premier meeting for biotechnology professionals covering a broad range of hot topics in the biotechnology industry. Attracting participants from academia, industry and regulatory, this meeting features sessions that aim to address emerging subjects of interest and allows for open exchange between scientists. The 2013 conference featured leading researchers in the fields of antibody-drug conjugates (ADCs) and immunogenicity. Herein, we present a summary of the ADC hot topics, including bioanalytical and PK considerations, quantitative evaluation of the impact of immunogenicity and ADME to understand ADC drug-drug interactions, and clinical considerations for ADC development. This article aims to summarize the recommendations that were made by the speakers during various sessions throughout the conference. PMID:24320125

  2. Double phase conjugate mirror in CdTe:Ge

    Science.gov (United States)

    Shcherbin, K.; Odoulov, S.; Rarenko, I.; Zakharuk, Z.

    2001-10-01

    The coherent oscillation in double phase conjugate mirror (DPCM) geometry at 1.064 μm with ac or dc electric field applied to CdTe:Ge sample is reported. The threshold of oscillations and the conversion efficiency are studied at different electric field, total light intensity and intensity ratio of the pump beams. The conversion efficiency up to 50% is reached with rather poor fidelity which can be improved by means of a cylindrical telescope. A new architecture of all optical interconnect is proposed. An auxiliary illumination is used to control the coupling strength of the sample, switching it either below or above the threshold of oscillation. A prototype of optical switch is built that can connect one emitter/receiver to two other emitters/receivers. A switching time less than 5 ms is achieved at the intensities of the recording and erasing beams less than 100 mW/cm2.

  3. Interactions of conjugate vaccines and co-administered vaccines.

    Science.gov (United States)

    Findlow, H; Borrow, R

    2016-01-01

    Conjugate vaccines play an important role in the prevention of infectious diseases such as those caused by the bacteria Haemophilus influenzae (Hi) type b (Hib), Neisseria meningitidis, and Streptococcus pneumoniae. Vaccines developed against these 3 pathogens utilize 3 main carrier proteins, non-toxic mutant of diphtheria toxin (CRM197), diphtheria toxoid (DT) and tetanus toxoid (TT). Current pediatric immunisation schedules include the administration of several vaccines simultaneously, therefore increasing the potential for immune interference (both positively and negatively) to the antigens administered. Knowledge of vaccine interactions is principally derived from clinical trials, these are reviewed here to explore immune interference which may result of from carrier-specific T-cell helper interactions, bystander interference and carrier induced epitopic suppression. PMID:26619353

  4. Multi GPU Performance of Conjugate Gradient Algorithm with Staggered Fermions

    CERN Document Server

    Kim, Hyung-Jin

    2010-01-01

    We report results of the performance test of GPUs obtained using the conjugate gradient (CG) algorithm for staggered fermions on the MILC fine lattice ($28^3 \\times 96$). We use GPUs of nVIDIA GTX 295 model for the test. When we turn off the MPI communication and use only a single GPU, the performance is 35 giga flops in double precision, which corresponds to 47% of the peak. When we turn on the MPI communication and use multi-GPUs, the performance is reduced down to 12.3 giga flops. The data transfer through the infiniband network and PCI-E bus I/O is a main bottle neck. We suggest two potential solutions of how to optimize the data transfer.

  5. Recombinogenic engineering of conjugative plasmids with fluorescent marker cassettes

    DEFF Research Database (Denmark)

    Reisner, A.; Molin, Søren; Zechner, E.L.

    2002-01-01

    An efficient approach for the insertion of fluorescent marker genes with sequence specificity into conjugative plasmids in Escherichia coli is described. For this purpose, homologous recombination of linear double-stranded targeting DNA was mediated by the bacteriophage lambda recombination...... functions using very short regions of homology. Initial manipulation of the IncFII target plasmids R1 and R1drd19 indicated that the linear targeting DNA should be devoid of all extraneous homologies to. the target molecule for optimal insertion specificity. Indeed, a simple recombination assay proved...... resistance genes and fluorescent markers. The choice of 5' non-homologous extensions in primer pairs used for amplifying the marker cassettes determines the site specificity of the targeting DNA. This methodology is applicable to the modification of all plasmids that replicate in E coli and is not restricted...

  6. Immunotoxins, ligand-toxin conjugates and molecular targeting.

    Science.gov (United States)

    Soria, M

    1989-01-01

    Biotechnology provides tools for therapeutic exploitation following advances in the elucidation of protein-to-cell and cell-to-cell interactions. Molecular targeting of bacterial and plant toxins to the desired district of action can be achieved through effector molecules like monoclonal antibodies or protein ligands. Biochemical conjugation of these effectors to SO-6, a single-chain Ribosome Inactivating Protein from Saponaria officinalis, yielded powerful cytotoxic agents that are attractive candidates for therapeutic evaluation. Cloning of the gene for this plant toxin has been achieved. Technologies for expression of protein ligands, such as apolipoproteins or several growth factors, are available in recombinant microorganisms, providing adequate partners for the assembly of targeted chimaeras. Domain engineering of structural and functional regions in effector proteins is now possible and will be carried out with the available technologies to improve existing therapy. PMID:2698471

  7. Evidence for fully conjugated double-stranded cycles.

    Science.gov (United States)

    Standera, Malte; Häfliger, Rolf; Gershoni-Poranne, Renana; Stanger, Amnon; Jeschke, Gunnar; van Beek, Jacco D; Bertschi, Louis; Schlüter, A Dieter

    2011-10-17

    A chain of circumstantial evidence for the existence of the first fully conjugated, double-stranded cycles is presented. The products have the structure of the belt-region of fullerene C(84)(D(2)) and carry either four hexyl chains or four phenyl groups. The unsubstituted parent cycle is also presented. The chain of evidence is mainly based on mass spectrometric analysis and trapping reactions, the latter being supported by quantum mechanical calculations. It is also of importance that the phenyl-substituted and unsubstituted products cannot undergo a [1,5] hydrogen shift, the only reasonable side-reaction that recently could not be excluded for the alkyl-substituted analogue. It is concluded that the fully aromatic targets truly exist in the gas phase. Whether they can be generated in solution under the applied conditions cannot yet be firmly decided; theoretical evidence speaks against. PMID:21915923

  8. Role of triplet polaron pairs in conjugated polymer photophysics

    Science.gov (United States)

    Wesely, Elizabeth; Rothberg, Lewis; Marchetti, Alfred; Chen, Shaw; Geng, Yanhou; Culligan, Sean

    2007-03-01

    We measure the decay of the long-lived fluorescence of a conjugated oligofluorene at temperatures from 300 K to 20 K. We conclude that nearly all of this emission arises from geminate recombination of photogenerated polaron pairs to reform the singlet exciton, and that charge pair recombination represents a significant contribution to the overall fluorescence quantum yield. The unusual nonmonotonic decay dynamics of the delayed fluorescence can be explained if we assume interconversion between singlet and triplet polaron pairs on the submicrosecond time scale. (˜500 ns.) We are able to model the decay of the delayed fluorescence by assuming activated recombination from a Gaussian energy distribution of singlet polaron pairs centered 0.2 eV below the excited state and having a standard deviation of 0.12 eV. The model is relevant to recent work involving the measurement of singlet-triplet branching ratios and to the yields of electroluminescent devices.

  9. Relating Chromophoric and Structural Disorder in Conjugated Polymers

    CERN Document Server

    Simine, Lena

    2016-01-01

    The optoelectronic properties of amorphous conjugated polymers are sensitive to conformational disorder and spectroscopy provides the means for structural characterization of the fragments of the chain which interact with light - "chromophores". A faithful interpretation of spectroscopic conformational signatures, however, presents a key challenge. We investigate the relationship between the ground state optical gaps, the properties of the excited states, and the structural features of chromophores of a single molecule poly(3-hexyl)-thiophene (P3HT), using quantum-classical atomistic simulations. Our results demonstrate that chromophoric disorder reflects an interplay between excited state de-localization and electron-hole polarization, and is controlled by torsional disorder that is specifically associated with the presence of side chains. Within this conceptual framework, we predict and explain a counter-intuitive spectral signature of P3HT: a red-shifted absorption, despite shortening of chromophores, with...

  10. Solvent immersion nanoimprint lithography of fluorescent conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Whitworth, G. L.; Zhang, S.; Stevenson, J. R. Y.; Ebenhoch, B.; Samuel, I. D. W.; Turnbull, G. A. [Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-10-19

    Solvent immersion imprint lithography (SIIL) was used to directly nanostructure conjugated polymer films. The technique was used to create light-emitting diffractive optical elements and organic semiconductor lasers. Gratings with lateral features as small as 70 nm and depths of ∼25 nm were achieved in poly(9,9-dioctylfluorenyl-2,7-diyl). The angular emission from the patterned films was studied, comparing measurement to theoretical predictions. Organic distributed feedback lasers fabricated with SIIL exhibited thresholds for lasing of ∼40 kW/cm{sup 2}, similar to those made with established nanoimprint processes. The results show that SIIL is a quick, convenient and practical technique for nanopatterning of polymer photonic devices.

  11. QM/MM-MD simulations of conjugated polyelectrolytes

    DEFF Research Database (Denmark)

    Sjöqvist, Jonas; Linares, Mathieu; Mikkelsen, Kurt Valentin;

    2014-01-01

    A methodological development is reported for the study of luminescence properties of conjugated polyelectrolytes, encompassing systems in which dihedral rotational barriers are easily overcome at room temperature. The components of the model include (i) a molecular mechanics (MM) force field...... description of the solvent in its electronic ground state as well as the chromophore in its electronic ground and excited states, (ii) a conformational sampling by means of classical molecular dynamics (MD) in the respective electronic states, and (iii) spectral response calculations by means of the quantum....... In fluorescence spectroscopy, the experimental spectrum shows a vibrational progression that is not addressed by theory, but the theoretical band position is in excellent agreement with experiment, with a highly accurate description of the Stokes shift as a result....

  12. Conjugate Heat Transfer Analysis of Film Cooling Flows

    Institute of Scientific and Technical Information of China (English)

    Xiaochen LU; Peixue JIANG; Hideaki SUGISHITA; Hideyuki UECHI; Kiyoshi SUENAGA

    2006-01-01

    The objective of this study is to evaluate the potential of various grids to satisfactorily simulate the development of a cooling film, using a coupled computation that takes into account the full geometry. Detailed computations of a single row of 30 degrees round holes on a flat plate are presented for blowing ratios of 0.764, 1.01 and 1.54.The simulation results are compared well with experimental data. The two-layer model gave more accurate results but consumed much more computational time than the standard wall functions. The k-ε turbulence model with wall functions with appropriate values of y+ is suitable for practical use. The results show the importance of the conjugate calculation for accurately describing the influence of the heat transfer within the cooling film.

  13. Least-Squares Seismic Inversion with Stochastic Conjugate Gradient Method

    Institute of Scientific and Technical Information of China (English)

    Wei Huang; Hua-Wei Zhou

    2015-01-01

    With the development of computational power, there has been an increased focus on data-fitting related seismic inversion techniques for high fidelity seismic velocity model and image, such as full-waveform inversion and least squares migration. However, though more advanced than conventional methods, these data fitting methods can be very expensive in terms of computational cost. Recently, various techniques to optimize these data-fitting seismic inversion problems have been implemented to cater for the industrial need for much improved efficiency. In this study, we propose a general stochastic conjugate gradient method for these data-fitting related inverse problems. We first prescribe the basic theory of our method and then give synthetic examples. Our numerical experiments illustrate the potential of this method for large-size seismic inversion application.

  14. Monolignol ferulate conjugates are naturally incorporated into plant lignins

    Science.gov (United States)

    Karlen, Steven D.; Zhang, Chengcheng; Peck, Matthew L.; Smith, Rebecca A.; Padmakshan, Dharshana; Helmich, Kate E.; Free, Heather C. A.; Lee, Seonghee; Smith, Bronwen G.; Lu, Fachuang; Sedbrook, John C.; Sibout, Richard; Grabber, John H.; Runge, Troy M.; Mysore, Kirankumar S.; Harris, Philip J.; Bartley, Laura E.; Ralph, John

    2016-01-01

    Angiosperms represent most of the terrestrial plants and are the primary research focus for the conversion of biomass to liquid fuels and coproducts. Lignin limits our access to fibers and represents a large fraction of the chemical energy stored in plant cell walls. Recently, the incorporation of monolignol ferulates into lignin polymers was accomplished via the engineering of an exotic transferase into commercially relevant poplar. We report that various angiosperm species might have convergently evolved to natively produce lignins that incorporate monolignol ferulate conjugates. We show that this activity may be accomplished by a BAHD feruloyl–coenzyme A monolignol transferase, OsFMT1 (AT5), in rice and its orthologs in other monocots. PMID:27757415

  15. Tumor Selective Silencing Using an RNAi-Conjugated Polymeric Nanopharmaceutical.

    Science.gov (United States)

    Svenson, Sonke; Case, Roy I; Cole, Roderick O; Hwang, Jungyeon; Kabir, Sujan R; Lazarus, Douglas; Lim Soo, Patrick; Ng, Pei-Sze; Peters, Christian; Shum, Pochi; Sweryda-Krawiec, Beata; Tripathi, Snehlata; van der Poll, Derek; Eliasof, Scott

    2016-03-01

    Small interfering RNA (siRNA) therapeutics have potential advantages over traditional small molecule drugs such as high specificity and the ability to inhibit otherwise "undruggable" targets. However, siRNAs have short plasma half-lives in vivo, can induce a cytokine response, and show poor cellular uptake. Formulating siRNA into nanoparticles offers two advantages: enhanced siRNA stability against nuclease degradation beyond what chemical modification alone can provide; and improved site-specific delivery that takes advantage of the enhanced permeability and retention (EPR) effect. Existing delivery systems generally suffer from poor delivery to tumors. Here we describe the formation and biological activity of polymeric nanopharmaceuticals (PNPs) based on biocompatible and biodegradable poly(lactic-co-glycolic acid) (PLGA) conjugated to siRNA via an intracellular cleavable disulfide linker (PLGA-siRNA). Additionally, these PNPs contain (1) PLGA conjugated to polyethylene glycol (PEG) for enhanced pharmacokinetics of the nanocarrier; (2) a cation for complexation of siRNA and charge compensation to avoid high negative zeta potential; and (3) neutral poly(vinyl alcohol) (PVA) to stabilize the PNPs and support the PEG shell to prevent particle aggregation and protein adsorption. The biological data demonstrate that these PNPs achieve prolonged circulation, tumor accumulation that is uniform throughout the tumor, and prolonged tumor-specific knockdown. PNPs employed in this study had no effect on body weight, blood cell count, serum chemistry, or cytokine response at doses >10 times the effective dose. PNPs, therefore, constitute a promising solution for achieving durable siRNA delivery and gene silencing in tumors. PMID:26835715

  16. Efficacy of conjugate vaccines in pneumococcal infection prevention

    Directory of Open Access Journals (Sweden)

    A. L. Perova

    2014-01-01

    Full Text Available The problem of pneumococcal infection is actual for many countries of the world in connection with high incidence and mortality. Vaccination by the 7-valent conjugated pneumococcal vaccine of children till 2 years is available in Russia since 2009, 13-valent – since 2012. Objectives – an assessment of clinical and epidemiological efficacy in pneumococcal infection prevention infection by catamnesis after 7-valent conjugated pneumococcal vaccine application. Observation over incidence of pneumonia and otitis of 50 children imparted against a pneumococcal infection is made. The indicator of density of incidence of pneumonia in group of the imparted made 9,7 on 1000 (95% of CI; 9,1–10,3 in group of comparison – 92,6 on 1000 (95% of CI; 91,3–93,9. Index of efficacy of vaccination concerning pneumonia of any etiology – 9,5, effectiveness ratio – 89,5%. The indicator of density of incidence of otitis at the imparted was 1,8 times less – 155,3 on 1000 (95% of CI; 150,9–155,7 in group of comparison – 263,9 on 1000 (95% of CI; 261,7–266,1. The index and vaccination effectiveness ratio concerning acute otitis media made 1,8 and 44,3%. Thus, vaccination against pneumococcal infection is effective as concerning community acquired pneumonia, and acute otitis media of any etiology.

  17. Formation of protein-oligosaccharide conjugates by laccase and tyrosinase.

    Science.gov (United States)

    Selinheimo, Emilia; Lampila, Piritta; Mattinen, Maija-Liisa; Buchert, Johanna

    2008-05-14

    Proteins and certain carbohydrates contain phenolic moieties, which are potential sites for modification of the function of the biopolymers. In this study, the capability of two different fungal oxidative enzymes, laccase from Trametes hirsuta (ThL) and tyrosinase from Trichoderma reesei (TrT), to catalyze formation of hetero-cross-linking between tyrosine side chains of alpha-casein and phenolic acids of hydrolyzed oat spelt xylan (hOSX) was studied. Formation of reaction products was followed by size exclusion chromatography (SEC), fluorescence spectroscopy, and SDS-PAGE, using specific staining methods for proteins and protein-carbohydrate conjugates. ThL and TrT were observed to differ significantly in their ability to catalyze the formation of protein-carbohydrate conjugates or the linking of the small molecular weight phenolic compounds to alpha-casein. The efficiency of these enzymes to directly cross-link protein also differed notably. TrT was able to cross-link alpha-casein more efficiently than ThL. ThL-catalyzed casein cross-linking was significantly enhanced by ferulic acid, p-coumaric acid, and also hOSX. The main reaction products by ThL appeared to be phenolic acid-bridged alpha-caseins. Indications of hetero-cross-link formation between alpha-casein and hOSX by both oxidative enzymes could be visualized by glycoprotein-specific staining in the SDS-PAGE analysis, although ThL was observed to be more effective in the heteroconjugate formation than TrT. PMID:18422326

  18. Improved cellular activity of antisense peptide nucleic acids by conjugation to a cationic peptide-lipid (CatLip) domain

    DEFF Research Database (Denmark)

    Koppelhus, Uffe; Shiraishi, Takehiko; Zachar, Vladimir;

    2008-01-01

    for future in vivo applications. We find that simply conjugating a lipid domain (fatty acid) to the cationic peptide (a CatLip conjugate) increases the biological effect of the corresponding PNA (CatLip) conjugates in a luciferase cellular antisense assay up to 2 orders of magnitude. The effect increases...

  19. Humoral and cell-mediated immunity following vaccination with synthetic Candida cell wall mannan derived heptamannoside-protein conjugate: immunomodulatory properties of heptamannoside-BSA conjugate.

    Science.gov (United States)

    Paulovičová, Lucia; Paulovičová, Ema; Karelin, Alexander A; Tsvetkov, Yury E; Nifantiev, Nikolay E; Bystrický, Slavomír

    2012-10-01

    Chemically defined glycoprotein conjugate composed of synthetically prepared mannan-derived heptamannoside with terminal β-1,2-linked mannose residue attached to the α-1,3-linked mannose residues and BSA as carrier protein (M7-BSA conjugate) was analysed for the capacity to induce protective humoral immunity and appropriate alteration cellular immunity. To identify protective antigenic structure of Candida cell wall mannan M7-BSA conjugate was used for BALB/c mice immunization. The obtained results were compared with placebo group and with heat-inactivated C. albicans whole cells immunization. The administration route of M7-BSA conjugate secondary booster injection significantly affected the intensity of humoral immune response and the specificity of produced antibodies. All prepared sera were able to elevate candidacidal activity of polymorphonuclear leukocytes (PMN) in cooperation with complement. Moreover, polyclonal sera obtained after secondary subcutaneous (s.c.) booster injection of M7-BSA conjugate were able to induce candidacidal activity of PMN also in complement independent manner. M7-BSA conjugate immunization induced increases of phagocytic activity and respiratory burst of granulocytes, caused a raise of the proportion of CD3(+) T lymphocytes and increased the CD4(+)/CD8(+) T lymphocyte ratio. We observed also an increasing proportion of CD4(+)CD25(+) T cells compared to immunization with heat inactivated whole C. albicans cells, which in turn promoted an increase of the CD8(+)CD25(+) cell proportion. Immunization with M7-BSA conjugate induced Th1, Th2 and Th17 immune responses as indicated by the elevation of relevant cytokines levels. These data provide some insights on the immunomodulatory properties of oligomannosides and contribute to the development of synthetic oligosaccharide vaccines against fungal diseases.

  20. Synthesis and photophysicochemical studies of a water soluble conjugate between folic acid and zinc tetraaminophthalocyanine

    Energy Technology Data Exchange (ETDEWEB)

    Khoza, Phindile; Antunes, Edith [Department of Chemistry, Rhodes University, PO Box 94, Grahamstown (South Africa); Chen, Ji-Yao [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za [Department of Chemistry, Rhodes University, PO Box 94, Grahamstown (South Africa)

    2013-02-15

    This work reports on the synthesis of zinc tetraaminophthalocyanine (ZnTAPc) functionalized with folic acid (FA), forming ZnTAPcFA. The conjugate between FA and ZnTAPc was soluble in water whereas ZnTAPc alone is not. The structure of ZnTAPcFA conjugate was elucidated by {sup 1}H NMR, MALDI-TOF mass and FTIR spectra. Photophysical and photochemical studies of ZnTAPcFA were conducted in DMSO. The increase in fluorescence quantum yield of the conjugate was accompanied by a decrease in the triplet and singlet oxygen quantum yields. The changes in triplet quantum and singlet oxygen quantum yields were marginal when ZnTAPc was simply mixed with FA without a chemical bond. - Highlights: Black-Right-Pointing-Pointer A conjugate between folic acid and a zinc tetraaminophthalocyanine was formed. Black-Right-Pointing-Pointer The conjugate is water soluble even though the phthalocyanine alone is not. Black-Right-Pointing-Pointer The fluorescence quantum yield of the conjugate was enhanced compared to the phthalocyanine alone. Black-Right-Pointing-Pointer Triplet quantum yields decreased for the conjugate.

  1. Development and technology transfer of Haemophilus influenzae type b conjugate vaccines for developing countries.

    Science.gov (United States)

    Beurret, Michel; Hamidi, Ahd; Kreeftenberg, Hans

    2012-07-13

    This paper describes the development of a Haemophilus influenzae type b (Hib) conjugate vaccine at the National Institute for Public Health and the Environment/Netherlands Vaccine Institute (RIVM/NVI, Bilthoven, The Netherlands), and the subsequent transfer of its production process to manufacturers in developing countries. In 1998, at the outset of the project, the majority of the world's children were not immunized against Hib because of the high price and limited supply of the conjugate vaccines, due partly to the fact that local manufacturers in developing countries did not master the Hib conjugate production technology. To address this problem, the RIVM/NVI has developed a robust Hib conjugate vaccine production process based on a proven model, and transferred this technology to several partners in India, Indonesia, Korea and China. As a result, emerging manufacturers in developing countries acquired modern technologies previously unavailable to them. This has in turn facilitated their approach to producing other conjugate vaccines. As an additional spin-off from the project, a World Health Organization (WHO) Hib quality control (QC) course was designed and conducted at the RIVM/NVI, resulting in an increased regulatory capacity for conjugate vaccines in developing countries at the National Regulatory Authority (NRA) level. For the local populations, this has translated into an increased and sustainable supply of affordable Hib conjugate-containing combination vaccines. During the course of this project, developing countries have demonstrated their ability to produce large quantities of high-quality modern vaccines after a successful transfer of the technology.

  2. Conjugated ionomers for photovoltaic applications: electric field driven charge separation in organic photovoltaics. Final Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Lonergan, Mark [Univ. of Oregon, Eugene, OR (United States)

    2015-05-29

    Final technical report for Conjugated ionomers for photovoltaic applications, electric field driven charge separation in organic photovoltaics. The central goal of the work we completed was been to understand the photochemical and photovoltaic properties of ionically functionalized conjugated polymers (conjugated ionomers or polyelectrolytes) and energy conversion systems based on them. We primarily studied two classes of conjugated polymer interfaces that we developed based either upon undoped conjugated polymers with an asymmetry in ionic composition (the ionic junction) or doped conjugated polymers with an asymmetry in doping type (the p-n junction). The materials used for these studies have primarily been the polyacetylene ionomers. We completed a detailed study of p-n junctions with systematically varying dopant density, photochemical creation of doped junctions, and experimental and theoretical work on charge transport and injection in polyacetylene ionomers. We have also completed related work on the use of conjugated ionomers as interlayers that improve the efficiency or organic photovoltaic systems and studied several important aspects of the chemistry of ionically functionalized semiconductors, including mechanisms of so-called "anion-doping", the formation of charge transfer complexes with oxygen, and the synthesis of new polyfluorene polyelectrolytes. We also worked worked with the Haley group at the University of Oregon on new indenofluorene-based organic acceptors.

  3. Calculation method of sliding ratios for conjugate-curve gear pair and its application

    Institute of Scientific and Technical Information of China (English)

    梁栋; 陈兵奎; 高艳娥

    2015-01-01

    The calculation method of sliding ratios for conjugate-curve gear pair, generated based on the theory of conjugate curves, is proposed. The theoretical model of conjugate-curve gear drive is briefly introduced. The general calculation formulas of sliding ratios are developed according to the conjugate curves. The applications to the circular arc gears based on conjugate curves and the novel involute-helix gears are studied. A comparison on the sliding coefficient with the conventional corresponding gear drive is also carried out. The influences of gear parameters such as spiral parameter, gear ratio and modulus on the sliding ratios of gear drive are discussed. Brief description of manufacturing method for conjugate-curve gear pair is given. The research results show that the sliding ratios of gear pair become smaller with the increase of spiral parameter and gear ratio, respectively. And it will be greater with the increase of modulus for the tooth profiles. The meshing characteristics of conjugate-curve gears are further reflected and the optimization design of tooth profiles with high performance may be obtained.

  4. Con-A conjugated mucoadhesive microspheres for the colonic delivery of diloxanide furoate.

    Science.gov (United States)

    Anande, Nalini M; Jain, Sunil K; Jain, Narendra K

    2008-07-01

    The aim of the research work was to develop cyst-targeted novel concanavalin-A (Con-A) conjugated mucoadhesive microspheres of diloxanide furoate (DF) for the effective treatment of amoebiasis. Eudragit microspheres of DF were prepared using emulsification-solvent evaporation method. Formulations were characterized for particle size and size distribution, % drug entrapment, surface morphology and in vitro drug release in simulated gastrointestinal (GI) fluids. Eudragit microspheres of DF were conjugated with Con-A. IR spectroscopy and DSC were used to confirm successful conjugation of Con-A to Eudragit microspheres while Con-A conjugated microspheres were further characterized using the parameters of zeta potential, mucoadhesiveness to colonic mucosa and Con-A conjugation efficiency with microspheres. IR studies confirmed the attachment of Con-A with Eudragit microspheres. All the microsphere formulations showed good % drug entrapment (78+/-5%). Zeta potential of Eudragit microspheres and Con-A conjugated Eudragit microspheres were found to be 3.12+/-0.7mV and 16.12+/-0.5mV, respectively. Attachment of lectin to the Eudragit microspheres significantly increases the mucoadhesiveness and also controls the release of DF in simulated GI fluids. Gamma scintigraphy study suggested that Eudragit S100 coated gelatin capsule retarded the release of Con-A conjugated microspheres at low pH and released microspheres slowly at pH 7.4 in the colon.

  5. Influence of the spacer on the inhibitory effect of different polycarbophil-protease inhibitor conjugates.

    Science.gov (United States)

    Marschütz, M K; Veronese, F M; Bernkop-Schnürch, A

    2001-09-01

    Within the present study various polycarbophil (PCP)-serine protease inhibitor conjugates were synthesized and the influence of different spacers on their inhibitory efficacy was evaluated in vitro. Results demonstrated that 4.2+/-0.15 units (n=3; +/-SD) of alpha-chymotrypsin were inhibited by 50% utilizing 0.86% (w/v) of a PCP-tetramethylenediamine (TMDA)-chymostatin 20:1 conjugate. In contrast, only 0.6+/-0.05 units (n=3; +/-SD) of alpha-chymotrypsin were inhibited by a corresponding PCP-poly(ethylene glycol) (PEG)-chymostatin conjugate. Inhibitory effects of PCP-TMDA-antipain and -elastatinal conjugates towards trypsin and elastase, respectively, were also significantly higher (P<0.05) than those of corresponding PCP-PEG-inhibitor conjugates. Hence, the great impact of the molecular size as well as the structure of the spacer on resulting polymer-inhibitor conjugates could be demonstrated. The small and rigid C4-spacer TMDA (molecular weight (MW) 161.1) was thereby shown to be highly advantageous over a long, hydrophilic and flexible PEG-diamine spacer (MW 3400). Results obtained should provide helpful basic knowledge for the development of mucoadhesive polymer-inhibitor conjugates used as auxiliary agents for the oral administration of peptide drugs.

  6. Sequential radioimmunoassay of unconjugated and conjugated estrogen in male human plasma.

    Directory of Open Access Journals (Sweden)

    Ohashi,Teruhisa

    1979-06-01

    Full Text Available A sequential radioimmunoassay procedure for unconjugated and conjugated estrone, estradiol-17 beta and estriol in male human plasma was developed. The blank values in this assay for unconjugated estrone, estradiol-17 beta, estriol conjugated estrone, estradiol-17 beta and conjugated estriol were 0.36 +/- 1.14 pg, 3.90 +/- 2.75 pg, 2.25 +/- 2.08 pg, 0.92 +/- 1.51 pg, 5.02 +/- 2.86 pg and 3.12 +/- 2.97 pg, respectively. Mean values of unconjugated estrone, estradiol-17 beta, estriol, conjugated estrone, estradiol-17 beta and conjugated estriol in plasma from 28 normal adult males were 38.4 +/- 13.4 pg/ml, 32.6 +/- 9.90 pg/ml, 4.06 +/- 3.68 pg/ml, 34.2 +/- 13.8 pg/ml, 40.4 +/- 12.3 pg/ml and 31.8 +/- 7.41 pg/ml, respectively. Both unconjugated and conjugated estrogen levels in patients with liver cirrhosis were elevated and conjugated estrogen, especially estriol levels, in patients with renal insufficiency were markedly elevated.

  7. Precise construction of oligonucleotide-Fab fragment conjugate for homogeneous immunoassay using HaloTag technology.

    Science.gov (United States)

    Päkkilä, Henna; Peltomaa, Riikka; Lamminmäki, Urpo; Soukka, Tero

    2015-03-01

    The use of oligonucleotide-protein conjugates enables the development of novel types of bioanalytical assays. However, convenient methods for producing covalent and stoichiometric oligonucleotide-protein conjugates are still rare. Here we demonstrate, for the first time, covalent conjugation of DNA oligonucleotide to Fab fragments with a 1:1 ratio using HaloTag self-labeling technology. The oligonucleotide coupling was carried out while the Fab was attached to protein G matrix, thereby enabling straightforward production of covalent conjugates. Furthermore, it allowed convenient purification of the product because the unreacted components were easily removed before the elution of the high-purity conjugate. The prepared conjugate was employed in a homogeneous immunoassay where prostate-specific antigen was used as a model analyte. Switchable lanthanide luminescence was used for detection, and the obtained limit of detection was 0.27 ng/ml. In the future, the developed method for covalent conjugation and successive purification in protein G column could also be applied for introducing other kinds of modifications to Fab fragments in a simple and site-specific manner.

  8. Anticancer activity of drug conjugates in head and neck cancer cells.

    Science.gov (United States)

    Majumdar, Debatosh; Rahman, Mohammad Aminur; Chen, Zhuo Georgia; Shin, Dong M

    2016-01-01

    Sexually transmitted oral cancer/head and neck cancer is increasing rapidly. Human papilloma virus (HPV) is playing a role in the pathogenesis of a subset of squamous cell carcinoma of head and neck (SCCHN). Paclitaxel is a widely used anticancer drug for breast, ovarian, testicular, cervical, non-small cell lung, head and neck cancer. However, it is water insoluble and orally inactive. We report the synthesis of water soluble nanosize conjugates of paclitaxel, branched PEG, and EGFR-targeting peptide by employing native chemical ligation. We performed a native chemical ligation between the N-hydroxy succinimide (NHS) ester of paclitaxel succinate and cysteine at pH 6.5 to give the cysteine-conjugated paclitaxel derivative. The thiol functionality of cysteine was activated and subsequently conjugated to multiarm thiol-PEG to obtain the paclitaxel branched PEG conjugate. Finally, we conjugated an EGFR-targeting peptide to obtain conjugates of paclitaxel, branched PEG, and EGFR-targeting peptide. These conjugates show anticancer activity against squamous cell carcinoma of head and neck cells (SCCHN, Tu212). PMID:27100344

  9. Uptake of Single-Walled Carbon Nanotubes Conjugated with DNA by Microvascular Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Joseph Harvey

    2012-01-01

    Full Text Available Single-walled carbon nanotubes (SWCNTs have been proposed to have great therapeutic potential. SWCNTs conjugated with drugs or genes travel in the systemic circulation to reach target cells or tissues following extravasation from microvessels although the interaction between SWCNT conjugates and the microvascular endothelial cells (ECs remains unknown. We hypothesized that SWCNT-DNA conjugates would be taken up by microvascular ECs and that this process would be facilitated by SWCNTs compared to facilitation by DNA alone. ECs were treated with various concentrations of SWCNT-DNA-FITC conjugates, and the uptake and intracellular distribution of these conjugates were determined by a confocal microscope imaging system followed by quantitative analysis of fluorescence intensity. The uptake of SWCNT-DNA-FITC conjugates (2 μg/mL by microvascular ECs was significantly greater than that of DNA-FITC (2 μg/mL, observed at 6 hrs after treatment. For the intracellular distribution, SWCNT-DNA-FITC conjugates were detected in the nucleus of ECs, while DNA-FITC was restricted to the cytoplasm. The fluorescence intensity and distribution of SWCNTs were concentration and time independent. The findings demonstrate that SWCNTs facilitate DNA delivery into microvascular ECs, thus suggesting that SWCNTs serving as drug and gene vehicles have therapeutic potential.

  10. Conjugation of the mycotoxins alternariol and alternariol monomethyl ether in tobacco suspension cells.

    Science.gov (United States)

    Hildebrand, Andreas A; Kohn, Beate N; Pfeiffer, Erika; Wefers, Daniel; Metzler, Manfred; Bunzel, Mirko

    2015-05-20

    The mycotoxins alternariol (AOH) and alternariol-9-O-methyl ether (AME) carry three and two phenolic hydroxyl groups, respectively, which makes them candidates for the formation of conjugated metabolites in plants. Such conjugates may escape routine methods of analysis and have therefore been termed masked or, more recently, modified mycotoxins. We report now that AOH and AME are extensively conjugated in suspension cultures of tobacco BY-2 cells. Five conjugates of AOH were identified by MS and NMR spectroscopy as β-D-glucopyranosides (attached in AOH 3- or 9-position) as well as their 6'-malonyl derivatives, and as a gentiobiose conjugate. For AME, conjugation resulted in the d-glucopyranoside (mostly attached in the AME 3-position) and its 6'- and 4'-malonyl derivatives. Pronounced differences were noted for the quantitative pattern of AOH and AME conjugates as well as for their phytotoxicity. Our in vitro study demonstrates for the first time that masked mycotoxins of AOH and AME can be formed in plant cells.

  11. Chitosan-isoniazid conjugates: Synthesis, evaluation of tuberculostatic activity, biodegradability and toxicity.

    Science.gov (United States)

    Berezin, Alexander S; Skorik, Yury A

    2015-08-20

    Novel water-soluble chitosan-isoniazid conjugates were synthesized by two methods: (1) the carbodiimide method using isoniazid (INH) and N-(2-carboxyethyl)chitosan (CEC), and (2) the reaction between INH and N-(3-chloro-2-hydroxypropyl)chitosan (CHPC). The solubility of the conjugates under physiological conditions was enhanced by phosphorylation. Method (1) is preferable in terms of obtaining conjugates with a high content of active substance; depending on reaction conditions, the degree of substitution in the INH-CEC conjugates varies from 0.08 to 0.39. Ultrasound treatment increased the reaction rate by a factor of 1.3-1.5, but caused partial degradation of the polymer. Consecutive modification led to a considerable decrease in polymer biodegradability in the following order: chitosan>CEC or CHPC>conjugate. In vitro screening of the antimicrobial activity against Mycobacterium tuberculosis H37Rv demonstrated a comparable or slightly higher minimum inhibitory concentration for conjugates than for INH itself (0.20, 0.25, and 1.05 μg INH/mL for INH, CEC-INH, and CHPC-INH, respectively). A slug mucosal irritation test employing Limax flavus revealed a lower toxicity for the conjugates than for INH by a factor of 3-4; the most noticeable toxicity decrease was observed for the conjugates obtained by method (1). Studies of acute toxicity in mice revealed a 3-4-fold increase in median lethal dose for the conjugates compared with INH (LD50 210, 850, and 650 mg INH/kg for INH, CEC-INH, and CHPC-INH, respectively). PMID:25965488

  12. METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method to solve the elastic conjugate surfaces in multi-teeth meshing is presented. In mechanicalmanufacturing and design, there exist a lot of problems relating to conjugate surfaces, such as three-dimensionalengagement, steel rolling and workpiece machining, which cause great effects on the quality of machining andperformances of transmission. This method describes relation between conjugate motion and elastic deformation in theprocess of mesh-in and mesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

  13. Surface doping of conjugated polymers by graphene oxide and its application for organic electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yan [Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195 (United States); State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Zhejiang-California International Nanosystems Institute, Zhejiang University, Hangzhou 310027 (China); Yip, Hin-Lap; Chen, Kung-Shih; Acton, Orb; Sun, Ying [Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195 (United States); O' Malley, Kevin M.; Ting, Guy [Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195 (United States); Chen, Hongzheng [State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Zhejiang-California International Nanosystems Institute, Zhejiang University, Hangzhou 310027 (China); Jen, Alex K.Y. [Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA 98195 (United States); Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195 (United States)

    2011-04-26

    Surface doping of conjugated polymers is realized by depositing a thin layer of graphene oxide (GO) on top of the polymers. The high proton density and the unique 2D structure of GO facilitate the protonic surface doping of conjugated polymers to achieve high conductivities. This finding represents a new strategy for improving charge transport across the metal/conjugated polymer interface to achieve much improved performance in organic solar cells. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Lensless two-photon imaging through a multicore fiber with coherence-gated digital phase conjugation

    Science.gov (United States)

    Conkey, Donald B.; Stasio, Nicolino; Morales-Delgado, Edgar E.; Romito, Marilisa; Moser, Christophe; Psaltis, Demetri

    2016-04-01

    We performed near-diffraction limited two-photon fluorescence (TPF) imaging through a lensless, multicore-fiber (MCF) endoscope utilizing digital phase conjugation. The phase conjugation technique is compatible with commercially available MCFs with high core density. We demonstrate focusing of ultrashort pulses through an MCF and show that the method allows for resolution that is not limited by the MCF core spacing. We constructed TPF images of fluorescent beads and cells by digital scanning of the phase-conjugated focus on the target object and collection of the emitted fluorescence through the MCF.

  15. A monoclonal antibody-Pseudomonas toxin conjugate that specifically kills multidrug-resistant cells.

    OpenAIRE

    FitzGerald, D J; Willingham, M C; Cardarelli, C O; Hamada, H; Tsuruo, T.; Gottesman, M M; Pastan, I

    1987-01-01

    One form of multidrug resistance is due to the expression of a 170-kDa energy-dependent drug efflux pump called P-glycoprotein in the plasma membranes of human cancer cells. We have prepared conjugates of Pseudomonas toxin with the anti-P-glycoprotein monoclonal antibody MRK-16. These anti-P-glycoprotein-toxin conjugates specifically kill multidrug-resistant human KB cells. Similar conjugates could be useful in cancer therapy to reduce or eliminate multidrug-resistant tumor populations in tum...

  16. Synthesis, characterization, and in vivo efficacy evaluation of PGG–docetaxel conjugate for potential cancer chemotherapy

    Directory of Open Access Journals (Sweden)

    Jiang X

    2012-02-01

    Full Text Available Danbo Yang1, Sang Van2, Yingyi Shu1, Xiaoqing Liu1, Yangfeng Ge1, Xinguo Jiang3, Yi Jin2, Lei Yu1,21Biomedical Engineering and Technology Institute, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, People’s Republic of China; 2Biomedical Group, Nitto Denko Technical Corporation, CA, USA; 3School of Pharmacy, Fudan University, Shanghai, People’s Republic of ChinaAim: This work is intended to develop and evaluate a biopolymeric poly(L-γ-glutamyl-glutamine (PGG–docetaxel (DTX conjugate that can spontaneously self-assemble in aqueous solutions to become nanoparticles.Methods: DTX was covalently attached to hydrophilic PGG by direct esterification, and the conjugate was characterized by proton nuclear magnetic resonance spectroscopy, molecular weight gel permeation chromatography, solubility, size distribution and morphology, and hemolysis. Conjugated DTX was found to have 2000 times improved water solubility compared with free DTX. Dynamic light scattering, transmission electron microscopy, and atomic force microscopy revealed the particle size, distribution and morphology of the PGG–DTX conjugate. In addition, the conjugate was further tested for in vitro cytotoxicity and in vivo antitumor efficacy on the human non-small cell lung cancer cell line NCI-H460.Results: Conjugated DTX was found to have 2000 times improved water solubility compared with free DTX. The conjugate formed nanoparticles with an average diameter of 30 nm in spherical shape and unimodal particle size distribution. The conjugate exhibited about 2% hemolysis at 10 mg/mL, compared with 56% for Tween 80® at 0.4 mg/mL, and 33% for Cremophor EL® at 10 mg/mL. In addition, the conjugate was further tested for in vitro cytotoxicity and in vivo antitumor efficacy on the human non-small cell lung cancer cell line NCI-H460. As expected, conjugated DTX exhibited lower cytotoxicity compared to that of free DTX, in concentration

  17. Emulsifying properties of maillard conjugates produced from sodium caseinate and locust bean gum

    OpenAIRE

    F. A. Perrechil; Santana, R.C.; D. B. Lima; M. Z. Polastro; Cunha, R. L.

    2014-01-01

    Emulsifying properties of sodium caseinate -locust bean gum Maillard conjugates produced at different temperatures (54 - 96 ºC), protein/polysaccharide ratios (0.3 - 1.0) and reaction times (1 - 24 hours) were evaluated. Conjugate formation was confirmed by formation of color and high molecular weight fractions and the decrease of the αs- and β-casein bands. The emulsions stabilized by Maillard conjugates showed good stability. The mean droplet diameter (d32) tended to decrease with the incre...

  18. Targeted images of KB cells using folate-conjugated gold nanoparticles

    Science.gov (United States)

    Rathinaraj, Pierson; Lee, Kyubae; Park, Soo-Young; Kang, Inn-Kyu

    2015-01-01

    Mercaptosuccinic acid-coated gold (GM) nanoparticles were prepared and characterized by transmission electron microscopy and dynamic light scattering. Folic acid (F) was then conjugated to the GM to preferentially target oral squamous cancer (KB) cells with folate receptors expressed on their membranes and facilitate the transit of the nanoparticles across the cell membrane. Finally, a fluorescence dye (Atto) was conjugated to the nanoparticles to visualize their internalization into KB cells. After culture of the cells in a medium containing GM and folate-conjugated GM (GF), the interaction of surface-modified gold nanoparticles with KB cells was studied.

  19. Conjugate variables in quantum field theory and a refinement of Paulis theorem

    CERN Document Server

    Pottel, Steffen

    2016-01-01

    For the case of spin zero we construct conjugate pairs of operators on Fock space. On states multiplied by polarization vectors coordinate operators Q conjugate to the momentum operator P exist. The massive case is derived from a geometrical quantity, the massless case is realized by taking the limit mass going to zero on the one hand, on the other from conformal transformations. Crucial is the norm problem of the states on which the Q's act: they determine eventually how many independent conjugate pairs exist. It is intriguing that light wedge variables and hence the wedge-local case seems to be preferred.

  20. Role of the conjugated spacer in the optimization of second-order nonlinear chromophores

    Science.gov (United States)

    Pérez-Moreno, Javier; Clays, Koen; Kuzyk, Mark G.

    2009-08-01

    We investigate the role of the conjugated spacer in the optimization of the first hyperpolarizability of organic chromophores. We propose a novel strategy for the optimization of the first hyperpolarizability that is based on the variation of the degree of conjugation for the bridge that separates the donor and acceptors at the end of push-pull type chromophores. The correlation between the type of conjugated spacer and the experimental nonlinear performance of the chromophores is investigated and interpreted in the context of the quantum limits.