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Sample records for heteroatomic conjugated molecules

  1. To bend or not to bend – are heteroatom interactions within conjugated molecules effective in dictating conformation and planarity?

    KAUST Repository

    Conboy, Gary; Spencer, Howard J.; Angioni, Enrico; Kanibolotsky, Alexander L.; Findlay, Neil J.; Coles, Simon J.; Wilson, Claire; Pitak, Mateusz B.; Risko, Chad; Coropceanu, Veaceslav; Bredas, Jean-Luc; Skabara, Peter J.

    2016-01-01

    We consider the roles of heteroatoms (mainly nitrogen, the halogens and the chalcogens) in dictating the conformation of linear conjugated molecules and polymers through non-covalent intramolecular interactions. Whilst hydrogen bonding is a competitive and sometimes more influential interaction, we provide unambiguous evidence that heteroatoms are able to determine the conformation of such materials with reasonable predictability.

  2. To bend or not to bend – are heteroatom interactions within conjugated molecules effective in dictating conformation and planarity?

    KAUST Repository

    Conboy, Gary

    2016-04-26

    We consider the roles of heteroatoms (mainly nitrogen, the halogens and the chalcogens) in dictating the conformation of linear conjugated molecules and polymers through non-covalent intramolecular interactions. Whilst hydrogen bonding is a competitive and sometimes more influential interaction, we provide unambiguous evidence that heteroatoms are able to determine the conformation of such materials with reasonable predictability.

  3. Single-Molecule Electronics with Cross- Conjugated Molecules: Quantum Interference, IETS and Non-Equilibrium "Temperatures"

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo

    Abstract The idea of using single-molecules as components in electronic devices is fas- cinating. For this idea to come into fruition, a number of technical and theo- retical challenges must be overcome. In this PhD thesis, the electron-phonon interaction is studied for a special class of molecules......, which is characterised by destructive quantum interference. The molecules are cross-conjugated, which means that the two parts of the molecules are conjugated to a third part, but not to each other. This gives rise to an anti-resonance in the trans- mission. In the low bias and low temperature regime......-conjugated molecules. We nd that the vibrational modes that would be expected to dominate, following the propensity, rules are very weak. Instead, other modes are found to be the dominant ones. We study this phenomenon for a number of cross-conjugated molecules, and link these ndings to the anti...

  4. 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.

  5. Bispecific small molecule-antibody conjugate targeting prostate cancer.

    Science.gov (United States)

    Kim, Chan Hyuk; Axup, Jun Y; Lawson, Brian R; Yun, Hwayoung; Tardif, Virginie; Choi, Sei Hyun; Zhou, Quan; Dubrovska, Anna; Biroc, Sandra L; Marsden, Robin; Pinstaff, Jason; Smider, Vaughn V; Schultz, Peter G

    2013-10-29

    Bispecific antibodies, which simultaneously target CD3 on T cells and tumor-associated antigens to recruit cytotoxic T cells to cancer cells, are a promising new approach to the treatment of hormone-refractory prostate cancer. Here we report a site-specific, semisynthetic method for the production of bispecific antibody-like therapeutics in which a derivative of the prostate-specific membrane antigen-binding small molecule DUPA was selectively conjugated to a mutant αCD3 Fab containing the unnatural amino acid, p-acetylphenylalanine, at a defined site. Homogeneous conjugates were generated in excellent yields and had good solubility. The efficacy of the conjugate was optimized by modifying the linker structure, relative binding orientation, and stoichiometry of the ligand. The optimized conjugate showed potent and selective in vitro activity (EC50 ~ 100 pM), good serum half-life, and potent in vivo activity in prophylactic and treatment xenograft mouse models. This semisynthetic approach is likely to be applicable to the generation of additional bispecific agents using drug-like ligands selective for other cell-surface receptors.

  6. Electrochemistry of conjugated planar anticancer molecules: Irinotecan and Sunitinib

    International Nuclear Information System (INIS)

    Zotti, Gianni; Berlin, Anna; Vercelli, Barbara

    2017-01-01

    The evaluation of drug levels is important for personalized therapeutic approaches particularly in cancer care. To this end electrochemistry provides simplicity, low cost, high sensitivity and possibility of miniaturization. Here we report the electrochemistry and UV-visible spectroscopy of two extensively used planar conjugated anticancer molecules, Irinotecan (ITC) and Sunitinib (SUN), in aprotic medium and water. Comparison is made with model compounds without amine ends. The electronic spectra of ITC and SUN in dimethylsulfoxide show similar vibronic patterns (0.2 eV vibrational energy for both) with energy gaps of 3.1 and 2.5 eV respectively. Cyclic voltammetry in acetonitrile shows the same one-electron reduction peak (-1.9 V vs Ag/Ag + ) and oxidation peaks at 1.45 and 0.65 V, both beyond the oxidation of the amine ends (0.45 V). In water the optical energy gaps are unchanged but the vibronic structure is almost lost and the oxidation processes are eased by 0.45 V for SUN and 1.10 V for ITC. The number of oxidatively exchanged electrons in water is two for ITC but four in two subsequent two-electron steps for SUN. The overall oxidation process for ITC likely involves the nucleophilic attack of a water molecule to the quinoline moiety. The first two-electron oxidation of SUN, involving the pyrrole moiety, leads possibly to the conjugated imine ring which is further oxidized to the N-oxide form. Lowering of the electron-transfer activation energy by water is assigned in part to release of molecular rigidity but in ITC the major role is assigned to a nucleophilic attack of water already in the activated state.

  7. Model Hamiltonian Calculations of the Nonlinear Polarizabilities of Conjugated Molecules.

    Science.gov (United States)

    Risser, Steven Michael

    This dissertation advances the theoretical knowledge of the nonlinear polarizabilities of conjugated molecules. The unifying feature of these molecules is an extended delocalized pi electron structure. The pi electrons dominate the electronic properties of the molecules, allowing prediction of molecular properties based on the treatment of just the pi electrons. Two separate pi electron Hamiltonians are used in the research. The principal Hamiltonian used is the non-interacting single-particle Huckel Hamiltonian, which replaces the Coulomb interaction among the pi electrons with a mean field interaction. The simplification allows for exact solution of the Hamiltonian for large molecules. The second Hamiltonian used for this research is the interacting multi-particle Pariser-Parr-Pople (PPP) Hamiltonian, which retains explicit Coulomb interactions. This limits exact solutions to molecules containing at most eight electrons. The molecular properties being investigated are the linear polarizability, and the second and third order hyperpolarizabilities. The hyperpolarizabilities determine the nonlinear optical response of materials. These molecular parameters are determined by two independent approaches. The results from the Huckel Hamiltonian are obtained through first, second and third order perturbation theory. The results from the PPP Hamiltonian are obtained by including the applied field directly in the Hamiltonian and determining the ground state energy at a series of field strengths. By fitting the energy to a polynomial in field strength, the polarizability and hyperpolarizabilities are determined. The Huckel Hamiltonian is used to calculate the third order hyperpolarizability of polyenes. These calculations were the first to show the average hyperpolarizability of the polyenes to be positive, and also to show the saturation of the hyperpolarizability. Comparison of these Huckel results to those from the PPP Hamiltonian shows the lack of explicit Coulomb

  8. Chemical de-conjugation for investigating the stability of small molecule drugs in antibody-drug conjugates.

    Science.gov (United States)

    Chen, Tao; Su, Dian; Gruenhagen, Jason; Gu, Christine; Li, Yi; Yehl, Peter; Chetwyn, Nik P; Medley, Colin D

    2016-01-05

    Antibody-drug conjugates (ADCs) offer new therapeutic options for advanced cancer patients through precision killing with fewer side effects. The stability and efficacy of ADCs are closely related, emphasizing the urgency and importance of gaining a comprehensive understanding of ADC stability. In this work, a chemical de-conjugation approach was developed to investigate the in-situ stability of the small molecule drug while it is conjugated to the antibody. This method involves chemical-mediated release of the small molecule drug from the ADC and subsequent characterization of the released small molecule drug by HPLC. The feasibility of this technique was demonstrated utilizing a model ADC containing a disulfide linker that is sensitive to the reducing environment within cancer cells. Five reducing agents were screened for use in de-conjugation; tris(2-carboxyethyl) phosphine (TCEP) was selected for further optimization due to its high efficiency and clean impurity profile. The optimized de-conjugation assay was shown to have excellent specificity and precision. More importantly, it was shown to be stability indicating, enabling the identification and quantification of the small molecule drug and its degradation products under different formulation pHs and storage temperatures. In summary, the chemical de-conjugation strategy demonstrated here offers a powerful tool to assess the in-situ stability of small molecule drugs on ADCs and the resulting information will shed light on ADC formulation/process development and storage condition selection. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Molecules with linear pi-conjugated pathways between all substituents : Omniconjugation

    NARCIS (Netherlands)

    van der Veen, M.H.; Rispens, M.T; Jonkman, H.T.; Hummelen, J.C.

    In this paper, omniconjugation is introduced as a topological phenomenon in pi-conjugated systems. Omniconjugated molecules are defined by the fact that they provide direct and fully pi-conjugated pathways between all subdstituents attached to them. Surprisingly, until now such topologies have never

  10. Molecules with Linear π-Conjugated Pathways between All Substituents : Omniconjugation

    NARCIS (Netherlands)

    Veen, Marleen H. van der; Rispens, Minze T.; Jonkman, Harry T.; Hummelen, Jan C.

    2004-01-01

    In this paper, omniconjugation is introduced as a topological phenomenon in π-conjugated systems. Omniconjugated molecules are defined by the fact that they provide direct and fully π-conjugated pathways between all substituents attached to them. Surprisingly, until now such topologies have never

  11. Strong overtones modes in inelastic electron tunneling spectroscopy with cross-conjugated molecules

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2013-01-01

    . With this in mind, we investigate a spectroscopic method capable of providing insight into these junctions for cross-conjugated molecules: inelastic electron tunneling spectroscopy (IETS). IETS has the advantage that the molecule interface is probed directly by the tunneling current. Previously, it has been thought...... and leading to suppressed levels of elastic current. In most theoretical studies, only the elastic contributions to the current are taken into account. In this paper, we study the inelastic contributions to the current in cross-conjugated molecules and find that while the inelastic contribution to the current...

  12. Biotin conjugated organic molecules and proteins for cancer therapy: A review.

    Science.gov (United States)

    Maiti, Santanu; Paira, Priyankar

    2018-02-10

    The main transporter for biotin is sodium dependent multivitamin transporter (SMVT), which is overexpressed in various aggressive cancer cell lines such as ovarian (OV 2008, ID8), leukemia (L1210FR), mastocytoma (P815), colon (Colo-26), breast (4T1, JC, MMT06056), renal (RENCA, RD0995), and lung (M109) cancer cell lines. Furthermore, its overexpression was found higher to that of folate receptor. Therefore, biotin demand in the rapidly growing tumors is higher than normal tissues. Several biotin conjugated organic molecules has been reported here for selective delivery of the drug in cancer cell. Biotin conjugated molecules are showing higher fold of cytotoxicity in biotin positive cancer cell lines than the normal cell. Nanoparticles and polymer surface modified drugs and biotin mediated cancer theranostic strategy was highlighted in this review. The cytotoxicity and selectivity of the drug in cancer cells has enhanced after biotin conjugation. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  13. Conductance mechanism in a linear non-conjugated trimethylsilyl-acetylene molecule: tunneling through localized states

    NARCIS (Netherlands)

    Petrov, E.G.; Marchenko, A.; Kapitanchuk, O.; Katsonis, Nathalie Hélène; Fichou, D.

    2014-01-01

    The conductance properties of 1,3-(trimethylsilyl)-1-tridecene-6,12-diyne, a non-conjugated trimethylsil-acetylene molecule have been investigated both experimentally and theoretically. Based on scanning tunnelling spectroscopy experiments, a discussion on the mechanisms controlling the charge

  14. Spectral multitude and spectral dynamics reflect changing conjugation length in single molecules of oligophenylenevinylenes

    KAUST Repository

    Kobayashi, Hiroyuki; Tsuchiya, Kousuke; Ogino, Kenji; Vacha, Martin

    2012-01-01

    Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable estimation of the phenylene torsional barriers. © 2012 The Owner Societies.

  15. Cytotoxicity Effects of Different Surfactant Molecules Conjugated to Carbon Nanotubes on Human Astrocytoma Cells

    Science.gov (United States)

    Dong, Lifeng; Witkowski, Colette M.; Craig, Michael M.; Greenwade, Molly M.; Joseph, Katherine L.

    2009-12-01

    Phase contrast and epifluorescence microscopy were utilized to monitor morphological changes in human astrocytoma cells during a time-course exposure to single-walled carbon nanotube (SWCNT) conjugates with different surfactants and to investigate sub-cellular distribution of the nanotube conjugates, respectively. Experimental results demonstrate that cytotoxicity of the nanotube/surfactant conjugates is related to the toxicity of surfactant molecules attached on the nanotube surfaces. Both sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) are toxic to cells. Exposure to CNT/SDS conjugates (0.5 mg/mL) for less than 5 min caused changes in cell morphology resulting in a distinctly spherical shape compared to untreated cells. In contrast, sodium cholate (SC) and CNT/SC did not affect cell morphology, proliferation, or growth. These data indicate that SC is an environmentally friendly surfactant for the purification and dispersion of SWCNTs. Epifluorescence microscopy analysis of CNT/DNA conjugates revealed distribution in the cytoplasm of cells and did not show adverse effects on cell morphology, proliferation, or viability during a 72-h incubation. These observations suggest that the SWCNTs could be used as non-viral vectors for diagnostic and therapeutic molecules across the blood-brain barrier to the brain and the central nervous system.

  16. Bonding and vibrational dynamics of a large π-conjugated molecule on a metal surface

    International Nuclear Information System (INIS)

    Temirov, R; Soubatch, S; Lassise, A; Tautz, F S

    2008-01-01

    The interplay between the substrate bonding of a large π-conjugated semiconductor molecule and the dynamical properties of the metal-organic interface is studied, employing the prototypical PTCDA/Ag(111) monolayer as an example. Both the coupling of molecular vibrations to the electron-hole-pair continuum of the metal surface and the inelastic scattering of tunnelling electrons by the molecular vibrations on their passage through the molecule are considered. The results of both types of experiment are consistent with the findings of measurements which probe the geometric and electronic structure of the adsorbate-substrate complex directly; generally speaking, they can be understood in the framework of standard theories for the electron-vibron coupling. While the experiments reported here in fact provide additional qualitative insights into the substrate bonding of our π-conjugated model molecule, their detailed quantitative understanding would require a full calculation of the dynamical interface properties, which is currently not available

  17. Crystal growth of new charge-transfer salts based on π-conjugated donor molecules

    Energy Technology Data Exchange (ETDEWEB)

    Morherr, Antonia, E-mail: morherr@stud.uni-frankfurt.de [Physikalisches Institut, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main (Germany); Witt, Sebastian [Physikalisches Institut, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main (Germany); Chernenkaya, Alisa [Graduate School Materials Science in Mainz, 55128 Mainz (Germany); Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Bäcker, Jan-Peter [Physikalisches Institut, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main (Germany); Schönhense, Gerd [Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Bolte, Michael [Institut für anorganische Chemie, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main (Germany); Krellner, Cornelius [Physikalisches Institut, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main (Germany)

    2016-09-01

    New charge transfer crystals of π-conjugated, aromatic molecules (phenanthrene and picene) as donors were obtained by physical vapor transport. The melting behavior, optimization of crystal growth and the crystal structure are reported for charge transfer salts with (fluorinated) tetracyanoquinodimethane (TCNQ-F{sub x}, x=0, 2, 4), which was used as acceptor material. The crystal structures were determined by single-crystal X-ray diffraction. Growth conditions for different vapor pressures in closed ampules were applied and the effect of these starting conditions for crystal size and quality is reported. The process of charge transfer was investigated by geometrical analysis of the crystal structure and by infrared spectroscopy on single crystals. With these three different acceptor strengths and the two sets of donor materials, it is possible to investigate the distribution of the charge transfer systematically. This helps to understand the charge transfer process in this class of materials with π-conjugated donor molecules.

  18. Convergence problems and energetic regions in π excited states of certain conjugated molecules

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.; Barros, H.G. de P.L. de.

    1980-01-01

    When calculating π bond orders of excited and superexcited states of conjugated molecules, difficulties arise in applying the variation method; besides, the convergence problems involved are well known. For pyridazine, chosen for discussion, 27 states are considered; the convergence problem is envisaged through two criteria in the choice of a parameter introduced in the compromise Hamiltonian. This convergence parameter is related to the variation method. There exist three particular solutions for bond orders, which divide the 27 states into energetical regions. (Author) [pt

  19. CdS nanowires formed by chemical synthesis using conjugated single-stranded DNA molecules

    Science.gov (United States)

    Sarangi, S. N.; Sahu, S. N.; Nozaki, S.

    2018-03-01

    CdS nanowires were successfully grown by chemical synthesis using two conjugated single-stranded (ss) DNA molecules, poly G (30) and poly C (30), as templates. During the early stage of the synthesis with the DNA molecules, the Cd 2+ interacts with Poly G and Poly C and produces the (Cd 2+)-Poly GC complex. As the growth proceeds, it results in nanowires. The structural analysis by grazing angle x-ray diffraction and transmission electron microscopy confirmed the zinc-blende CdS nanowires with the growth direction of . Although the nanowires are well surface-passivated with the DNA molecules, the photoluminescence quenching was caused by the electron transfer from the nanowires to the DNA molecules. The quenching can be used to detect and label the DNAs.

  20. Control Strategy for Small Molecule Impurities in Antibody-Drug Conjugates.

    Science.gov (United States)

    Gong, Hai H; Ihle, Nathan; Jones, Michael T; Kelly, Kathleen; Kott, Laila; Raglione, Thomas; Whitlock, Scott; Zhang, Qunying; Zheng, Jie

    2018-04-01

    Antibody-drug conjugates (ADCs) are an emerging class of biopharmaceuticals. As such, there are no specific guidelines addressing impurity limits and qualification requirements. The current ICH guidelines on impurities, Q3A (Impurities in New Drug Substances), Q3B (Impurities in New Drug Products), and Q6B (Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products) do not adequately address how to assess small molecule impurities in ADCs. The International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) formed an impurities working group (IWG) to discuss this issue. This white paper presents a strategy for evaluating the impact of small molecule impurities in ADCs. This strategy suggests a science-based approach that can be applied to the design of control systems for ADC therapeutics. The key principles that form the basis for this strategy include the significant difference in molecular weights between small molecule impurities and the ADC, the conjugation potential of the small molecule impurities, and the typical dosing concentrations and dosing schedule. The result is that exposure to small impurities in ADCs is so low as to often pose little or no significant safety risk.

  1. n-Electrons of heteroatoms in hydrogen bond and luminescence

    International Nuclear Information System (INIS)

    Karyakin, A.V.

    1985-01-01

    Hydrogen bond energy in the process of interaction between water molecules, water molecules and heteroatoms of organic solvents, water molecules and inorganic compounds, is determined, its mechanism being studied. On the basis of X-ray structure and IR-spectroscopic data water state in easily hydrolized compounds of zirconium and hafnium, including sulfates, nitrates, oxychlorides etc. is analyzed. Water state in uranyl nitrate hydrates, the structure of the compounds and their behaviour when they are extracted by TBP, are considered. The reasons for stability of uranyl nitrate hydrates are discussed. The effect of n-electrons of heteroatoms of simple aromatic compound on structural spectra of luminescence in aliphatic and inorganic matrices is investigated

  2. Variable contact gap single-molecule conductance determination for a series of conjugated molecular bridges

    DEFF Research Database (Denmark)

    Haiss, W.; Wang, Christian; Jitchati, R.

    2008-01-01

    It is now becoming clear that the characteristics of the whole junction are important in determining the conductance of single molecules bound between two metal contacts. This paper shows through measurements on a series of seven conjugated molecular bridges that contact separation is an importan...... that conductance increases rather dramatically at higher tilt angle away from the normal for conformationally rigid molecular wires and that this increase in conductance arises from increased electronic coupling between the molecular bridge and the gold contacts.......It is now becoming clear that the characteristics of the whole junction are important in determining the conductance of single molecules bound between two metal contacts. This paper shows through measurements on a series of seven conjugated molecular bridges that contact separation is an important......-distance curves and knowledge of the terminal to terminal length of the molecular wire. The contact gap separation dependence is interpreted as arising from tilting of these molecules in the junction and this model is underpinned by ab initio transport computations. In this respect we make the general observation...

  3. Multi-small molecule conjugations as new targeted delivery carriers for tumor therapy

    Directory of Open Access Journals (Sweden)

    Shan L

    2015-09-01

    Full Text Available Lingling Shan,1 Ming Liu,2 Chao Wu,1 Liang Zhao,1 Siwen Li,3 Lisheng Xu,1 Wengen Cao,1 Guizhen Gao,1 Yueqing Gu3 1Institute of Pharmaceutical Biotechnology, School of Biology and Food Engineering, Suzhou University, Suzhou, People’s Republic of China; 2Department of Biology, University of South Dakota, Vermillion, SD, USA; 3Department of Biomedical Engineering, School of Life Science and Technology, China Pharmaceutical University, Nanjing, People’s Republic of China Abstract: In response to the challenges of cancer chemotherapeutics, including poor physicochemical properties, low tumor targeting ability, and harmful side effects, we developed a new tumor-targeted multi-small molecule drug delivery platform. Using paclitaxel (PTX as a model therapeutic, we prepared two prodrugs, ie, folic acid-fluorescein-5(6-isothiocyanate-arginine-paclitaxel (FA-FITC-Arg-PTX and folic acid-5-aminofluorescein-glutamic-paclitaxel (FA-5AF-Glu-PTX, composed of folic acid (FA, target, amino acids (Arg or Glu, linker, and fluorescent dye (fluorescein in vitro or near-infrared fluorescent dye in vivo in order to better understand the mechanism of PTX prodrug targeting. In vitro and acute toxicity studies demonstrated the low toxicity of the prodrug formulations compared with the free drug. In vitro and in vivo studies indicated that folate receptor-mediated uptake of PTX-conjugated multi-small molecule carriers induced high antitumor activity. Notably, compared with free PTX and with PTX-loaded macromolecular carriers from our previous study, this multi-small molecule-conjugated strategy improved the water solubility, loading rate, targeting ability, antitumor activity, and toxicity profile of PTX. These results support the use of multi-small molecules as tumor-targeting drug delivery systems. Keywords: multi-small molecules, paclitaxel, prodrugs, targeting, tumor therapy

  4. Impact of nuclear lattice relaxation on the excitation energy transfer along a chain of pi-conjugated molecules

    NARCIS (Netherlands)

    Schmid, S.A.; Abbel, R.J.; Schenning, A.P.H.J.; Meijer, E.W.; Herz, L.M.

    2010-01-01

    We have investigated the extent to which delocalization of the ground-state and excited-state wave functions of a p-conjugated molecule affects the excitation energy transfer (EET) between such molecules. Using femtosecond photoluminescence spectroscopy, we experimentally monitored the EET along

  5. Anisotropic charge transport in large single crystals of π-conjugated organic molecules.

    Science.gov (United States)

    Hourani, Wael; Rahimi, Khosrow; Botiz, Ioan; Koch, Felix Peter Vinzenz; Reiter, Günter; Lienerth, Peter; Heiser, Thomas; Bubendorff, Jean-Luc; Simon, Laurent

    2014-05-07

    The electronic properties of organic semiconductors depend strongly on the nature of the molecules, their conjugation and conformation, their mutual distance and the orientation between adjacent molecules. Variations of intramolecular distances and conformation disturb the conjugation and perturb the delocalization of charges. As a result, the mobility considerably decreases compared to that of a covalently well-organized crystal. Here, we present electrical characterization of large single crystals made of the regioregular octamer of 3-hexyl-thiophene (3HT)8 using a conductive-atomic force microscope (C-AFM) in air. We find a large anisotropy in the conduction with charge mobility values depending on the crystallographic orientation of the single crystal. The smaller conduction is in the direction of π-π stacking (along the long axis of the single crystal) with a mobility value in the order of 10(-3) cm(2) V(-1) s(-1), and the larger one is along the molecular axis (in the direction normal to the single crystal surface) with a mobility value in the order of 0.5 cm(2) V(-1) s(-1). The measured current-voltage (I-V) curves showed that along the molecular axis, the current followed an exponential dependence corresponding to an injection mode. In the π-π stacking direction, the current exhibits a space charge limited current (SCLC) behavior, which allows us to estimate the charge carrier mobility.

  6. Geometric and electronic structures of boron(III)-cored dyes tailored by incorporation of heteroatoms into ligands.

    Science.gov (United States)

    Sun, Lin; Zhang, Fan; Wang, Xinyang; Qiu, Feng; Xue, Minzhao; Tregnago, Giulia; Cacialli, Franco; Osella, Silvio; Beljonne, David; Feng, Xinliang

    2015-03-01

    Complexation of a boron atom with a series of bidentate heterocyclic ligands successfully gives rise to corresponding BF2-chelated heteroarenes, which could be considered as novel boron(III)-cored dyes. These dye molecules exhibit planar structures and expanded π-conjugated backbones due to the locked conformation with a boron center. The geometric and electronic structures of these BF2 complexes can be tailored by embedding heteroatoms in the unique modes to form positional isomer and isoelectronic structures. The structure-property relationship is further elucidated by studying the photophysical properties, electrochemical behavior and quantum-chemical calculations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Crystal engineering of giant molecules based on perylene diimide conjugated polyhedral oligomeric silsesquioxane nano-atom

    Science.gov (United States)

    Ren, He

    . In such "bottom-up" approach, the precise fabrication of 2 nm 100 nm nanostructures, is of great research interest. In this thesis, crystal engineering of giant molecules based on PDI conjugated POSS Nano-Atom (PDI-BPOSS) nano-atoms via self-assembly is performed and studied. Herein, three different giant molecules were synthesized: shape amphiphile, m-phenyl-(PDI-BPOSS)2 (S1) and tetrahedron, R-(PDI-BPOSS)4 (S2) and S-(PDI-BPOSS)4 (S3). Single crystals were grown for S1 and S2, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) were performed, and crystal structures of these samples were determined, while hexagonal superlattice without crystal order can be observed for S3 to exhibit crystal-like morphology.

  8. Conjugated donor-acceptor-acceptor (D-A-A) molecule for organic nonvolatile resistor memory.

    Science.gov (United States)

    Dong, Lei; Li, Guangwu; Yu, An-Dih; Bo, Zhishan; Liu, Cheng-Liang; Chen, Wen-Chang

    2014-12-01

    A new donor-acceptor-acceptor (D-A-A) type of conjugated molecule, N-(4-(N',N'-diphenyl)phenylamine)-4-(4'-(2,2-dicyanovinyl)phenyl) naphthalene-1,8-dicarboxylic monoimide (TPA-NI-DCN), consisting of triphenylamine (TPA) donors and naphthalimide (NI)/dicyanovinylene (DCN) acceptors was synthesized and characterized. In conjunction with previously reported D-A based materials, the additional DCN moiety attached as end group in the D-A-A configuration can result in a stable charge transfer (CT) and charge-separated state to maintain the ON state current. The vacuum-deposited TPA-NI-DCN device fabricated as an active memory layer was demonstrated to exhibit write-once-read-many (WORM) switching characteristics of organic nonvolatile memory due to the strong polarity of the TPA-NI-DCN moiety. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. An enzymatic deconjugation method for the analysis of small molecule active drugs on antibody-drug conjugates.

    Science.gov (United States)

    Li, Yi; Gu, Christine; Gruenhagen, Jason; Yehl, Peter; Chetwyn, Nik P; Medley, Colin D

    2016-01-01

    Antibody-drug conjugates (ADCs) are complex therapeutic agents that use the specific targeting properties of antibodies and the highly potent cytotoxicity of small molecule drugs to selectively eliminate tumor cells while limiting the toxicity to normal healthy tissues. Two critical quality attributes of ADCs are the purity and stability of the active small molecule drug linked to the ADC, but these are difficult to assess once the drug is conjugated to the antibody. In this study, we report a enzyme deconjugation approach to cleave small molecule drugs from ADCs, which allows the drugs to be subsequently characterized by reversed-phase high performance liquid chromatography. The model ADC we used in this study utilizes a valine-citrulline linker that is designed to be sensitive to endoproteases after internalization by tumor cells. We screened several proteases to determine the most effective enzyme. Among the 3 cysteine proteases evaluated, papain had the best efficiency in cleaving the small molecule drug from the model ADC. The deconjugation conditions were further optimized to achieve complete cleavage of the small molecule drug. This papain deconjugation approach demonstrated excellent specificity and precision. The purity and stability of the active drug on an ADC drug product was evaluated and the major degradation products of the active drug were identified. The papain deconjugation method was also applied to several other ADCs, with the results suggesting it could be applied generally to ADCs containing a valine-citrulline linker. Our results indicate that the papain deconjugation method is a powerful tool for characterizing the active small molecule drug conjugated to an ADC, and may be useful in ensuring the product quality, efficacy and the safety of ADCs.

  10. Multiple-heteroatom-containing sulfur compounds in a high sulfur coal

    International Nuclear Information System (INIS)

    Winans, R.E.; Neill, P.H.

    1990-01-01

    Flash vacuum pyrolysis of a high sulfur coal has been combined with high resolution mass spectrometry yielding information on aromatic sulfur compounds containing an additional heteroatom. Sulfur emission from coal utilization is a critical problem and in order to devise efficient methods for removing organic sulfur, it is important to know what types of molecules contain sulfur. A high sulfur Illinois No. 6 bituminous coal (Argonne Premium Coal Sample No. 3) was pyrolyzed on a platinum grid using a quartz probe inserted into a modified all glass heated inlet system and the products characterized by high resolution mass spectrometry (HRMS). A significant number of products were observed which contained both sulfur and an additional heteroatom. In some cases two additional heteroatoms were observed. These results are compared to those found in coal extracts and liquefaction products

  11. Single-Molecule Luminescence and High Efficiency Photovoltaic Cells Based on Percolated Conducting Carbon Nanotubes Scaffolds Templated with Light-Harvesting Conjugated Polymers and Nanohybrids

    National Research Council Canada - National Science Library

    Yang, Arnold C

    2009-01-01

    .... Nanocomposites constructed by surface-grafted multiwall carbon nanotubes (CNTs) with conjugated polymers dispersed in a polymer matrix were synthesized to form novel optoelectronic materials that exploit single-molecule effects...

  12. Pro-aromatic and anti-aromatic π-conjugated molecules: an irresistible wish to be diradicals

    KAUST Repository

    Zeng, Zebing

    2015-01-01

    © 2015 The Royal Society of Chemistry. Aromaticity is an important concept to understand the stability and physical properties of π-conjugated molecules. Recent studies on pro-aromatic and anti-aromatic molecules revealed their irresistible tendency to become diradicals in the ground state. Diradical character thus becomes another very important concept and it is fundamentally correlated to the physical (optical, electronic and magnetic) properties and chemical reactivity of most of the organic optoelectronic materials. Molecules with distinctive diradical character show unique properties which are very different from those of traditional closed-shell π-conjugated systems, and thus they have many potential applications in organic electronics, spintronics, non-linear optics and energy storage. This critical review first introduces the fundamental electronic structure of Kekulé diradicals within the concepts of anti-aromaticity and pro-aromaticity in the context of Hückel aromaticity and diradical character. Then recent research studies on various stable/persistent diradicaloids based on pro-aromatic and anti-aromatic compounds are summarized and discussed with regard to their synthetic chemistry, physical properties, structure-property relationships and potential material applications. A summary and personal perspective is given at the end.

  13. Reversible multi-electron redox chemistry of π-conjugated N-containing heteroaromatic molecule-based organic cathodes

    Science.gov (United States)

    Peng, Chengxin; Ning, Guo-Hong; Su, Jie; Zhong, Guiming; Tang, Wei; Tian, Bingbing; Su, Chenliang; Yu, Dingyi; Zu, Lianhai; Yang, Jinhu; Ng, Man-Fai; Hu, Yong-Sheng; Yang, Yong; Armand, Michel; Loh, Kian Ping

    2017-07-01

    Even though organic molecules with well-designed functional groups can be programmed to have high electron density per unit mass, their poor electrical conductivity and low cycle stability limit their applications in batteries. Here we report a facile synthesis of π-conjugated quinoxaline-based heteroaromatic molecules (3Q) by condensation of cyclic carbonyl molecules with o-phenylenediamine. 3Q features a number of electron-deficient pyrazine sites, where multiple redox reactions take place. When hybridized with graphene and coupled with an ether-based electrolyte, an organic cathode based on 3Q molecules displays a discharge capacity of 395 mAh g-1 at 400 mA g-1 (1C) in the voltage range of 1.2-3.9 V and a nearly 70% capacity retention after 10,000 cycles at 8 A g-1. It also exhibits a capacity of 222 mAh g-1 at 20C, which corresponds to 60% of the initial specific capacity. Our results offer evidence that heteroaromatic molecules with multiple redox sites are promising in developing high-energy-density, long-cycle-life organic rechargeable batteries.

  14. A size exclusion-reversed phase two dimensional-liquid chromatography methodology for stability and small molecule related species in antibody drug conjugates.

    Science.gov (United States)

    Li, Yi; Gu, Christine; Gruenhagen, Jason; Zhang, Kelly; Yehl, Peter; Chetwyn, Nik P; Medley, Colin D

    2015-05-08

    Antibody drug conjugates (ADCs) are complex therapeutic agents combining the specific targeting properties of antibodies and highly potent cytotoxic small molecule drugs to selectively eliminate tumor cells while limiting the toxicity to normal healthy tissues. One unique critical quality attribute of ADCs is the content of unconjugated small molecule drug present from either incomplete conjugation or degradation of the ADC. In this work, size exclusion chromatography (SEC) was coupled with reversed-phase (RP) HPLC in an online 2-dimensional chromatography format for identification and quantitation of unconjugated small molecule drugs and related small molecule impurities in ADC samples directly without sample preparation. The SEC method in the 1st dimension not only separated the small molecule impurities from the intact ADC, but also provided information about the size variants (monomer, dimer, aggregates, etc.) of the ADC. The small molecule peak from the SEC was trapped and sent to a RP-HPLC in the 2nd dimension to further separate and quantify the different small molecule impurities present in the ADC sample. This SEC-RP 2D-LC method demonstrated excellent precision (%RSDmolecule degradation products and aggregation of the conjugate were observed in the stability samples and the degradation pathways of the ADC were investigated. This 2D-LC method offers a powerful tool for ADC characterization and provides valuable information for conjugation and formulation development. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. In vivo evaluation of an anti-PSMA antibody conjugated with varying numbers of biotin molecules in a pretargeting protocol

    International Nuclear Information System (INIS)

    Wilbur, D.S.; Hamlin, D.K.; Quinn, J.; Vessella, R.L.

    2003-01-01

    An investigation has been conducted to determine the effect of varying the number of biotin molecules conjugated with an anti-PSMA antibody (mAb) as part of our studies to optimize biotinylated antibodies and radiolabeled streptavidin in pretargeting protocols for Targeted Radionuclide Therapy of prostate cancer. In the investigation, the anti-PSMA antibody 107-1A4 was biotinylated with varying amounts of biotinamidocaproate N-hydroxysuccinimide ester. This procedure resulted in obtaining 107-1A4 with 2.3, 4.5, and 6.8 biotin conjugated as measured by the standard HABA assay. The biotinylated 107-1A4 was radioiodinated and was evaluated in a pretargeting protocol in athymic mice bearing LNCaP human tumor xenografts. In the protocol, 50 μg biotinylated [ 125 I]107-1A4 was injected, followed 48h later by 25 μg of avidin for blood clearance, and 1h after that 20 μg of radiolabeled succinylated recombinant streptavidin ([ 13 1I]sSAv) was administered. The tumor localization and tissue distribution was evaluated at 24, 48, and 72h post [ 131 I]sSAv injection. With 2.3 biotin/mAb, an approximate 1:1 molar ratio (4-5 pmol/g) of sSAv/mAb was obtained at all three time points. With 4.5 biotin/mAb, a 1:1 ratio was observed at 24h, but approx. 2: 1 was observed at 48 and 72h pi. With 6.8 biotin/mAb, sSAv/mAb ratios of approximately 1.5:1; 2:1; and 3:1 were obtained at 24, 48, and 72h pi respectively. The amount of sSAv localized in the tumor was nearly the same (4-5 pmol/g) when 107-1A4 had 2.3 or 4.5 biotin conjugated, but decreased to 3-4.5 pmol/g with 6.8 biotin conjugated. Because the highest levels of co-localized sSAv was found with the lowest number of biotin conjugates, the observed differences in ratios of sSAv/mAb may be best explained as differences in internalization, and degradation of mAb and protease resistant sSAv. In duplicate experiments, similar results were obtained with biotinylated 107-1A4 F(ab') 2 , but not with an mAb to a non-internalizing antigen

  16. Analysis of vibronic interactions in the molecules of cross-conjugated ketones

    Directory of Open Access Journals (Sweden)

    Kompaneez V.V.

    2017-01-01

    Full Text Available We have done quantitative analysis of vibronic parameters of two cross-conjugated δ-dimethylaminoketones. The research shows the influence of С-N and C=O bonds in the rings, and the radicals with nitro compounds on the vibronic parameters of characteristic bands, which describe the state (vibrations, types of deformation under excitation of the phenyl ring and the polyene bridge. Results described impact of the substituent’s nature on the parameters of intra- and intermolecular interactions presents for the studied compounds.

  17. Fluorescence resonance energy transfer between conjugated molecules infiltrated in three-dimensional opal photonic crystals

    International Nuclear Information System (INIS)

    Zou, Lu; Sui, Ning; Wang, Ying-Hui; Qian, Cheng; Ma, Yu-Guang; Zhang, Han-Zhuang

    2015-01-01

    Fluorescence resonance energy transfer (FRET) from Coumarin 6 (C-6) to Sulforhodamine B (S-B) infiltrated into opal PMMA (poly-methyl-methacrylate) photonic crystals (PCs) has been studied in detail. The intrinsic mesh micro-porous structure of opal PCs could increase the luminescent efficiency through inhibiting the intermolecular interaction. Meanwhile, its structure of periodically varying refractive indices could also modify the FRET through affecting the luminescence characteristics of energy donor or energy acceptor. The results demonstrate that the FRET efficiency between conjugated dyes was easily modified by opal PCs. - Highlights: • We investigate the fluorescence resonance energy transfer between two kinds of dyes. • These two kinds of dyes are infiltrated in PMMA opal photonic crystals. • The structure of opal PCs could improve the luminescent characteristics. • The structure of opal PCs could improve the energy transfer characteristics

  18. Spontaneous dissociation of a conjugated molecule on the Si(100) surface

    DEFF Research Database (Denmark)

    Lin, Rong; Galili, Michael; Quaade, Ulrich

    2002-01-01

    The adsorption mechanism of alpha-sexithiophene (alpha-6T) on the clean Si(100)-(2x1) surface has been investigated using scanning tunneling microscopy (STM) and first principles electronic structure calculations. We find that at submonolayer coverage, the alpha-6T molecules are not stable and di...

  19. Ultrafast Charge Generation Pathways in Photovoltaic Blends Based on Novel Star-Shaped Conjugated Molecules

    NARCIS (Netherlands)

    Kozlov, Oleg V.; Luponosov, Yuriy N.; Ponomarenko, Sergei A.; Kausch-Busies, Nina; Paraschuk, Dmitry Yu; Olivier, Yoann; Beljonne, David; Cornil, Jerome; Pshenichnikov, Maxim S.

    2015-01-01

    The quest for new materials is one of the main factors propelling recent advances in organic photovoltaics. Star-shaped small molecules (SSMs) have been proven promising candidates as perspective donor material due to the increase in numbers of excitation pathways caused by the degeneracy of the

  20. Heteroatom doped graphene in photocatalysis: A review

    International Nuclear Information System (INIS)

    Putri, Lutfi Kurnianditia; Ong, Wee-Jun; Chang, Wei Sea; Chai, Siang-Piao

    2015-01-01

    Graphical abstract: - Highlights: • Doping graphene with foreign atoms extends its function in the photocatalyst system. • Chemically doped graphene improved the electrical conductivity. • Chemically doped graphene outperform conventional rGO as a semiconductor support. • Chemically doped graphene cause bandgap opening and formation of catalytic sites. • Chemically doped graphene can behave as functional standalone photocatalyst. - Abstract: Photocatalysis has been a focus of great attention due to its useful environmental applications such as eliminating hazardous pollutants and generating sustainable energy. Coincidentally, graphene, a 2D allotrope of carbon, has also infiltrated many research fields due to its outstanding properties – photocatalysis being no exception. As of recent, there has been growing research focus on heteroatom (O, N, B, P and S) doping of graphene and its emergent application opportunities. In this study, rather than the familiar graphene as the electron transfer medium that is normally integrated in a photocatalyst system, we contrarily explore the implication of heteroatom doped graphene and the underlying mechanism behind their advantageous uses in photocatalysis. This review surveys the literature and highlights recent progress and challenges in the development of chemically doped graphene in the photocatalysis scene. It is desired that this review will promote awareness and encourage further investigations for the development in this budding research area.

  1. Aptamer-conjugated DNA nano-ring as the carrier of drug molecules

    Science.gov (United States)

    Srivithya, Vellampatti; Roun, Heo; Sekhar Babu, Mitta; Hyung, Park Jae; Ha, Park Sung

    2018-03-01

    Due to its predictable self-assembly and structural stability, structural DNA nanotechnology is considered one of the main interdisciplinary subjects encompassing conventional nanotechnology and biotechnology. Here we have fabricated the mucin aptamer (MUC1)˗conjugated DNA nano˗ring intercalated with doxorubicin (DNRA˗DOX) as potential therapeutics for breast cancer. DNRA˗DOX exhibited significantly higher cytotoxicity to the MCF˗7 breast cancer cells than the controls, including DOX alone and the aptamer deficient DNA nano˗ring (DNR) with doxorubicin. Interactions between DOX and DNRA were studied using spectrophotometric measurements. Dose-dependent cytotoxicity was performed to prove that both DNR and DNRA were non-toxic to the cells. The drug release profile showed a controlled release of DOX at normal physiological pH 7.4, with approximately 61% released, but when exposed to lysosomal of pH 5.5, the corresponding 95% was released within 48 h. Owing to the presence of the aptamer, DNRA˗DOX was effectively taken up by the cancer cells, as confirmed by confocal microscopy, implying that it has potential for use in targeted drug delivery.

  2. A three-dimensional tetrahedral-shaped conjugated small molecule for organic solar cells

    Directory of Open Access Journals (Sweden)

    QIN Yang

    2014-04-01

    Full Text Available We report the synthesis of a novel three-dimensional tetrahedral-shaped small molecule,SO,containing a tetraphenylsilane core and cyanoester functionalized terthiophene arms.A deep lying HOMO energy level of -5.3 eV and a narrow bandgap of 1.9 eV were obtained from cyclic voltammetry measurements.Absorption,X-ray scattering and differential scanning calorimetry experiments all indicate high crystallinity of this compound.Solar cells employing SO were fabricated and evaluated.The relatively low performance was mainly ascribed to lack of appreciable phase separation,which is confirmed by optical microscopy.

  3. Analysis and removal of heteroatom containing species in coal liquid distillate over NiMo catalysts

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Sumbogo Murtia; Ki-Hyouk Choi; Kinya Sakanishi; Osamu Okuma; Yozo Korai; Isao Mochida [Kyushu University, Fukuoka (Japan). Institute for Materials Chemistry and Engineering

    2005-02-01

    Heteroatom containing molecules in South Banko coal liquid (SBCL) distillate were identified with a gas chromatograph equipped with an atomic emission detector (GC-AED). Thiophenes and benzothiophenes were found to be the major sulfur compounds. Pyridines, anilines, and phenols were the major nitrogen and oxygen compounds, respectively. Reactivities of heteroatom containing species in hydrotreatment over conventional NiMoS/Al{sub 2}O{sub 3}, NiMoS/Al{sub 2}O{sub 3}-SiO{sub 2} catalysts were very different according to their cyclic structure as well as the kind of heteroatom in the species. The sulfur species were completely desulfurized over the catalysts examined in the present study by 60 min at 360{degree}C under initial hydrogen pressure of 5 MPa. However, hydrodenitrogenation was more difficult than hydrodesulfurization even at 450{degree}C. Anilines were found the most refractory ones among the nitrogen species. Hydrodeoxygenation of SBCL was also difficult in the hydrotreatment conditions examined in the present study. Dibenzofuran was the most refractory molecule among the oxygen species. A two-stage reaction configuration at 340 and 360{degree}C improved HDN and HDO reactivities, although the conversions were still insufficient. Increasing the acidity of the support as well as the loading of the metals on the NiMoS/Al{sub 2}O{sub 3} catalysts improved very much the heteroatom reduction to achieve complete removal of nitrogen by two-stage reaction configuration at 340-360{degree}C and oxygen at 360{degree}C, respectively. The addition of H{sub 2}S in the reaction atmosphere inhibited the HDN reaction but increased markedly the HDO conversion. The acidic support increased the activity in hydrotreatment through enhancing the hydrogenation activity, while H{sub 2}S maintained the catalyst in a sufficiently sulfided state. 19 refs., 4 figs., 8 tabs.

  4. Inflammation-Specific T1 Imaging Using Anti-Intercellular Adhesion Molecule 1 Antibody-Conjugated Gadolinium Diethylenetriaminepentaacetic Acid

    Directory of Open Access Journals (Sweden)

    Kyu-Sil Choi

    2007-03-01

    Full Text Available To examine inflammatory tissue, an initial and common symptom of various types of pathogenesis, we designed inflammation-targeted T1 contrast agents prepared by bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA with anti-intercellular adhesion molecule 1 (ICAM-1 antibody. The anti-ICAM-1 antibody was coupled with DTPA and was then conjugated with Gd. The specific binding of the Gd-DTPA-anti-ICAM-1 antibody complex to the ICAM-1-expressing cells was examined in the cultured endothelial cells where ICAM-1 expression was stimulated. Inflammation-specific T1 imaging was then assessed using a mouse abscess model with the 1.5-Tesla module. The Gd-DTPA-anti-ICAM-1 antibody displayed increased r1, which was two times higher than that of Gd-DTPA and showed predominant binding to cultured endothelial cells, which expressed a high level of ICAM-1. Moreover, the inflammation-specific T1 enhancement was imaged with the Gd-DTPA-anti-ICAM-1 antibody in the mouse acute inflammation model. The Gd-DTPA-anti-ICAM-1 antibody showed significantly increased vascular circulation time, which thereby offered a greater chance for its binding to the target cells. The Gd-DTPA-anti-ICAM-1 antibody displays a potential targeted T1 contrast agent specific to the inflammatory tissue that expresses ICAM-1.

  5. Transition metal-induced activation of alkynes leading to metal carbene species: synthetic application to new {pi}-conjugated molecules

    Energy Technology Data Exchange (ETDEWEB)

    Abo, T; Ohe, K [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)], E-mail: ohe@scl.kyoto-u.ac.jp

    2008-03-15

    The in situ generation of furylcarbene complexes by means of transition metals was applied to catalytic carbene reactions, such as Wittig-type olefination and cycloisomerization reactions. In the presence of [Rh(OAc){sub 2}]{sub 2} as a catalyst and triphenylphosphine as a carbene accepter, carbonyl-ene-ynes 1a reacted with benzaldehyde to give a 2-styrylfuran derivative 3a. The reaction involving phosphine-ylide formation followed by Wittig-type olefination with aldehydes was applied to synthesis of furfurylidene-containing p-extended conjugated molecules. A Ruthenium catalyst underwent cycloisomerization of 1,2-bis(carbonylenyl)acetylene 10a,b to afford 2,2'-bifuran structures. The crystal structure of 5,5'-diphenyl-2,2'-bifuran 11b was determined by X-ray crystallography. The ORTEP drawings of 11b exhibited transoid and highly planar structure. The emission bands of the bisfuran 11b were observed at 414 and 440 nm, its quantum yield (84%) was higher than that of a similar 5,5'-diphenyl-2,2'-bithiophene.

  6. The use of radiocobalt as a label improves imaging of EGFR using DOTA-conjugated Affibody molecule

    DEFF Research Database (Denmark)

    Garousi, Javad; Andersson, Ken G; Dam, Johan H

    2017-01-01

    -expressing xenografts in mice. An optimal combination of radionuclide, chelator and targeting protein may further improve the contrast of radionuclide imaging. The aim of this study was to evaluate the targeting properties of radiocobalt-labelled DOTA-ZEGFR:2377. DOTA-ZEGFR:2377 was labelled with (57)Co (T1/2 = 271.8 d......), (55)Co (T1/2 = 17.5 h), and, for comparison, with the positron-emitting radionuclide (68)Ga (T1/2 = 67.6 min) with preserved specificity of binding to EGFR-expressing A431 cells. The long-lived cobalt radioisotope (57)Co was used in animal studies. Both (57)Co-DOTA-ZEGFR:2377 and (68)Ga-DOTA......Several anti-cancer therapies target the epidermal growth factor receptor (EGFR). Radionuclide imaging of EGFR expression in tumours may aid in selection of optimal cancer therapy. The (111)In-labelled DOTA-conjugated ZEGFR:2377 Affibody molecule was successfully used for imaging of EGFR...

  7. The use of radiocobalt as a label improves imaging of EGFR using DOTA-conjugated Affibody molecule.

    Science.gov (United States)

    Garousi, Javad; Andersson, Ken G; Dam, Johan H; Olsen, Birgitte B; Mitran, Bogdan; Orlova, Anna; Buijs, Jos; Ståhl, Stefan; Löfblom, John; Thisgaard, Helge; Tolmachev, Vladimir

    2017-07-20

    Several anti-cancer therapies target the epidermal growth factor receptor (EGFR). Radionuclide imaging of EGFR expression in tumours may aid in selection of optimal cancer therapy. The 111 In-labelled DOTA-conjugated Z EGFR:2377 Affibody molecule was successfully used for imaging of EGFR-expressing xenografts in mice. An optimal combination of radionuclide, chelator and targeting protein may further improve the contrast of radionuclide imaging. The aim of this study was to evaluate the targeting properties of radiocobalt-labelled DOTA-Z EGFR:2377 . DOTA-Z EGFR:2377 was labelled with 57 Co (T 1/2  = 271.8 d), 55 Co (T 1/2  = 17.5 h), and, for comparison, with the positron-emitting radionuclide 68 Ga (T 1/2  = 67.6 min) with preserved specificity of binding to EGFR-expressing A431 cells. The long-lived cobalt radioisotope 57 Co was used in animal studies. Both 57 Co-DOTA-Z EGFR:2377 and 68 Ga-DOTA-Z EGFR:2377 demonstrated EGFR-specific accumulation in A431 xenografts and EGFR-expressing tissues in mice. Tumour-to-organ ratios for the radiocobalt-labelled DOTA-Z EGFR:2377 were significantly higher than for the gallium-labelled counterpart already at 3 h after injection. Importantly, 57 Co-DOTA-Z EGFR:2377 demonstrated a tumour-to-liver ratio of 3, which is 7-fold higher than the tumour-to-liver ratio for 68 Ga-DOTA-Z EGFR:2377 . The results of this study suggest that the positron-emitting cobalt isotope 55 Co would be an optimal label for DOTA-Z EGFR:2377 and further development should concentrate on this radionuclide as a label.

  8. Heteroatom-Doped Carbon Materials for Electrocatalysis.

    Science.gov (United States)

    Asefa, Tewodros; Huang, Xiaoxi

    2017-08-10

    Fuel cells, water electrolyzers, and metal-air batteries are important energy systems that have started to play some roles in our renewable energy landscapes. However, despite much research works carried out on them, they have not yet found large-scale applications, mainly due to the unavailability of sustainable catalysts that can catalyze the reactions employed in them. Currently, noble metal-based materials are the ones that are commonly used as catalysts in most commercial fuel cells, electrolyzers, and metal-air batteries. Hence, there has been considerable research efforts worldwide to find alternative noble metal-free and metal-free catalysts composed of inexpensive, earth-abundant elements for use in the catalytic reactions employed in these energy systems. In this concept paper, a brief introduction on catalysis in renewable energy systems, followed by the recent efforts to develop sustainable, heteroatom-doped carbon and non-noble metal-based electrocatalysts, the challenges to unravel their structure-catalytic activity relationships, and the authors' perspectives on these topics and materials, are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. White polymer light-emitting electrochemical cells using emission from exciplexes with long intermolecular distances formed between polyfluorene and π-conjugated amine molecules

    Science.gov (United States)

    Nishikitani, Y.; Takeuchi, H.; Nishide, H.; Uchida, S.; Yazaki, S.; Nishimura, S.

    2015-12-01

    The authors present white polymer light-emitting electrochemical cells (PLECs) fabricated with polymer blend films of poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and π-conjugated triphenylamine molecules. The PLECs have bulk heterojunction structures composed of van der Waals interfaces between the PFD segments and the amine molecules. White-light electroluminescence (EL) can be achieved via light-mixing of the blue exciton emission from PFD and long-wavelength exciplex emission from excited complexes consisting of PFD segments (acceptors (As)) and the amine molecules (donors (Ds)). Precise control of the distances between the PFD and the amine molecules, affected through proper choice of the concentrations of PFD, amine molecules, and polymeric solid electrolytes, is critical to realizing white emission. White PLECs can be fabricated with PFD and amine molecules whose highest occupied molecular orbital (HOMO) levels range from -5.3 eV to -5.0 eV. Meanwhile, PLECs fabricated with amine molecules whose HOMO levels are lower than -5.6 eV cannot produce exciplex emission. The distances between the PFD and amine molecules of the exciplexes appear to be larger than 0.4 nm. These experimental data are explained by perturbation theory using the charge-transfer state ( A - D + ), the locally excited state ( A * D ), which is assumed to be the locally excited acceptor state in which there is no interaction with the donor molecule; and the energy gap between the HOMO levels of the PFD and the amine molecules. Color-stable white PLECs were fabricated using 4,4',4″-tris[N-(2-naphthyl)-N-phenylamino]-triphenylamine, which has a HOMO level of -5.2 eV, as the amine molecule, and the color stability of the device is a function of the fact that PFD forms exciplexes with these molecules.

  10. Synthesis of Conjugated Small Molecules and Polymers by a Palladium Catalyzed Cyclopentannulation Strategy: Towards New Organic Semiconductors

    Science.gov (United States)

    Bheemireddy, Sambasiva Reddy

    The utility of conjugated small molecules and polymers as organic semiconductors have seen a tremendous growth in research and development in academia as well as industry because of their processability and flexibility advantages in comparison to inorganic semiconductors. The extensive research over the years has produced a large number of p-type (hole conducting) and n-type (electron conducting) semiconductors that can be used to construct organic electronic devices. Of these materials, p-type semiconductors are more established and extensively studied because of the ease of preparation as well as their better general stability in comparison to n-type materials. Despite recent research into the development of n-type materials, fullerene (C60 and C 70) and its derivatives are still the predominant materials used as electron acceptors for OPV applications. By taking advantage of the electron accepting behavior of cyclopenta[hi]aceanthrylene fragment of C70, we have designed and synthesized new materials based on cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). By using a newly developed palladium catalyzed cyclopentannulation methodology, 1,2,6,7- tetraarylcyclopenta[hi]aceanthrylenes were prepared by treating diarylethynylenes with 9,10-dibromoanthracene. Scholl cyclodehydrogenation was used to close the externally fused aryl groups to provide access to contorted 2,7,13,18- tetraalkoxytetrabenzo[f,h,r,t]rubicenes. The contortion provides access to more soluble materials than their planar counterparts but still ii allows significant pi-pi stacking between molecules. Using a modified palladium catalyzed cyclopentannulation polymerization followed by a cyclodehydrogenation reaction, a nonconventional synthesis of CP-PAH embedded ladder polymers was also achieved. These ladder polymers possess broad UV-Vis absorptions and narrow optical gaps of 1.17-1.29 eV. The synthesis of new donor-acceptor copolymers incorporating electron accepting 1,2,6,7- tetra(4

  11. Magnetic and transport properties of conjugated and cumulated molecules: the π-system enlightens part of the story

    DEFF Research Database (Denmark)

    Sarbadhikary, Prodipta; Shil, Suranjan; Misra, Anirban

    2018-01-01

    We have investigated the intramolecular magnetic exchange coupling constants (J) for a series of nitronyl nitroxide diradicals connected by a range of linear conjugated and cumulene couplers focusing on the unusual π-interaction properties within the couplers. Distance between radical centers, sp...

  12. Controlling Electrical Conductance through a π‐Conjugated Cruciform Molecule by Selective Anchoring to Gold Electrodes

    DEFF Research Database (Denmark)

    Huang, Cancan; Chen, Songjie; Ørnsø, Kristian Baruël

    2015-01-01

    Tuning charge transport at the single‐molecule level plays a crucial role in the construction of molecular electronic devices. Introduced herein is a promising and operationally simple approach to tune two distinct charge‐transport pathways through a cruciform molecule. Upon in situ cleavage of t...

  13. Asymmetric Conjugated Molecules Based on [1]Benzothieno[3,2-b][1]benzothiophene for High-Mobility Organic Thin-Film Transistors: Influence of Alkyl Chain Length.

    Science.gov (United States)

    He, Keqiang; Li, Weili; Tian, Hongkun; Zhang, Jidong; Yan, Donghang; Geng, Yanhou; Wang, Fosong

    2017-10-11

    Herein, we report the synthesis and characterization of a series of [1]benzothieno[3,2-b][1]benzothiophene (BTBT)-based asymmetric conjugated molecules, that is, 2-(5-alkylthiophen-2-yl)[1]benzothieno[3,2-b][1]benzothiophene (BTBT-Tn, in which T and n represent thiophene and the number of carbons in the alkyl group, respectively). All of the molecules with n ≥ 4 show mesomorphism and display smectic A, smectic B (n = 4), or smectic E (n > 4) phases and then crystalline phases in succession upon cooling from the isotropic state. Alkyl chain length has a noticeable influence on the microstructures of vacuum-deposited films and therefore on the performance of the organic thin-film transistors (OTFTs). All molecules except for 2-(thiophen-2-yl)[1]benzothieno[3,2-b][1]benzothiophene and 2-(5-ethylthiophen-2-yl)[1]benzothieno[3,2-b][1]benzothiophene showed OTFT mobilities above 5 cm 2 V -1 s -1 . 2-(5-Hexylthiophen-2-yl)[1]benzothieno[3,2-b][1]benzothiophene and 2-(5-heptylthiophen-2-yl)[1]benzothieno[3,2-b][1]benzothiophene showed the greatest OTFT performance with reliable hole mobilities (μ) up to 10.5 cm 2 V -1 s -1 because they formed highly ordered and homogeneous films with diminished grain boundaries.

  14. Look fast: Crystallization of conjugated molecules during solution shearing probed in-situ and in real time by X-ray scattering

    KAUST Repository

    Smilgies, Detlef Matthias; Li, Ruipeng; Giri, Gaurav; Chou, Kang Wei; Diao, Ying; Bao, Zhenan; Amassian, Aram

    2012-01-01

    High-speed solution shearing, in which a drop of dissolved material is spread by a coating knife onto the substrate, has emerged as a versatile, yet simple coating technique to prepare high-mobility organic thin film transistors. Solution shearing and subsequent drying and crystallization of a thin film of conjugated molecules is probed in situ using microbeam grazing incidence wide-angle X-ray scattering (μGIWAXS). We demonstrate the advantages of this approach to study solution based crystal nucleation and growth, and identify casting parameter combinations to cast highly ordered and laterally aligned molecular thin films. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Look fast: Crystallization of conjugated molecules during solution shearing probed in-situ and in real time by X-ray scattering

    KAUST Repository

    Smilgies, Detlef Matthias

    2012-12-20

    High-speed solution shearing, in which a drop of dissolved material is spread by a coating knife onto the substrate, has emerged as a versatile, yet simple coating technique to prepare high-mobility organic thin film transistors. Solution shearing and subsequent drying and crystallization of a thin film of conjugated molecules is probed in situ using microbeam grazing incidence wide-angle X-ray scattering (μGIWAXS). We demonstrate the advantages of this approach to study solution based crystal nucleation and growth, and identify casting parameter combinations to cast highly ordered and laterally aligned molecular thin films. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. DFT theoretical investigations of π-conjugated molecules based on thienopyrazine and different acceptor moieties for organic photovoltaic cells

    Directory of Open Access Journals (Sweden)

    Mohammed Bourass

    2016-09-01

    Full Text Available In this work, theoretical study by using the DFT method on eleven conjugated compounds based on thienopyrazine is reported. Different electron side groups were introduced to investigate their effects on the electronic structure; The HOMO, LUMO and Gap energy of these compounds have been calculated and reported in this paper. A systematic theoretical study of such compound has not been reported as we know. Thus, our aim is first, to explore their electronic and spectroscopic properties on the basis of the DFT quantum chemical calculations. Second, we are interested to elucidate the parameters that influence the photovoltaic efficiency toward better understanding of the structure–property relationships. The study of structural, electronic and optical properties for these compounds could help to design more efficient functional photovoltaic organic materials.

  17. Coumarin-BODIPY hybrids by heteroatom linkage: versatile, tunable and photostable dye lasers for UV irradiation.

    Science.gov (United States)

    Esnal, I; Duran-Sampedro, G; Agarrabeitia, A R; Bañuelos, J; García-Moreno, I; Macías, M A; Peña-Cabrera, E; López-Arbeloa, I; de la Moya, S; Ortiz, M J

    2015-03-28

    Linking amino and hydroxycoumarins to BODIPYs through the amino or hydroxyl group lets the easy construction of unprecedented photostable coumarin-BODIPY hybrids with broadened and enhanced absorption in the UV spectral region, and outstanding wavelength-tunable laser action within the green-to-red spectral region (∼520-680 nm). These laser dyes allow the generation of a valuable tunable UV (∼260-350 nm) laser source by frequency doubling, which is essential to study accurately the photochemistry of biological molecules under solar irradiation. The tunability is achieved by selecting the substitution pattern of the hybrid. Key factors are the linking heteroatom (nitrogen vs. oxygen), the number of coumarin units joined to the BODIPY framework and the involved linking positions.

  18. Conformational sensitivity of conjugated poly(ethylene oxide)-poly(amidoamine) molecules to cations adducted upon electrospray ionization – A mass spectrometry, ion mobility and molecular modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, Aura [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Chendo, Christophe [Aix-Marseille Université – CNRS, FR 1739, Fédération des Sciences Chimiques de Marseille, Spectropole, Marseille (France); Wang, Qi [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Viel, Stéphane [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Quéléver, Gilles; Peng, Ling [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Posocco, Paola [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Pricl, Sabrina, E-mail: sabrina.pricl@di3.units.it [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Charles, Laurence, E-mail: laurence.charles@univ-amu.fr [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France)

    2014-01-15

    Graphical abstract: -- Highlights: •ESI-MS/MS, IMS and molecular modeling were combined to study PEO-PAMAM conformation. •Protonated and lithiated molecules were studied, with charge states from 2 to 4. •Protonation mostly occurred on PAMAM, with PEO units enclosing the protonated group. •Lithium adduction on PEO units lead to more expanded conformations. •Charge location strongly influenced PEO-PAMAM dissociation behavior. -- Abstract: Tandem mass spectrometry and ion mobility spectrometry experiments were performed on multiply charged molecules formed upon conjugation of a poly(amidoamine) (PAMAM) dendrimer with a poly(ethylene oxide) (PEO) linear polymer to evidence any conformational modification as a function of their charge state (2+ to 4+) and of the adducted cation (H{sup +}vs Li{sup +}). Experimental findings were rationalized by molecular dynamics simulations. The G0 PAMAM head-group could accommodate up to three protons, with protonated terminal amine group enclosed in a pseudo 18-crown-6 ring formed by the PEO segment. This particular conformation enabled a hydrogen bond network which allowed long-range proton transfer to occur during collisionally activated dissociation. In contrast, lithium adduction was found to mainly occur onto oxygen atoms of the polyether, each Li{sup +} cation being coordinated by a 12-crown-4 pseudo structure. As a result, for the studied polymeric segment (M{sub n} = 1500 g mol{sup −1}), PEO-PAMAM hybrid molecules exhibited a more expanded shape when adducted to lithium as compared to proton.

  19. Oligothiophene-Indandione-Linked Narrow-Band Gap Molecules: Impact of π-Conjugated Chain Length on Photovoltaic Performance.

    Science.gov (United States)

    Komiyama, Hideaki; To, Takahiro; Furukawa, Seiichi; Hidaka, Yu; Shin, Woong; Ichikawa, Takahiro; Arai, Ryota; Yasuda, Takuma

    2018-04-04

    Solution-processed organic solar cells (OSCs) based on narrow-band gap small molecules hold great promise as next-generation energy-converting devices. In this paper, we focus on a family of A-π-D-π-A-type small molecules, namely, BDT- nT-ID ( n = 1-4) oligomers, consisting of benzo[1,2- b:4,5- b']dithiophene (BDT) as the central electron-donating (D) core, 1,3-indandione (ID) as the terminal electron-accepting (A) units, and two regioregular oligo(3-hexylthiophene)s ( nT) with different numbers of thiophene rings as the π-bridging units, and elucidate their structure-property-function relationships. The effects of the length of the π-bridging nT units on the optical absorption, thermal behavior, morphology, hole mobility, and OSC performance were systematically investigated. All oligomers exhibited broad and intense visible photoabsorption in the 400-700 nm range. The photovoltaic performances of bulk heterojunction OSCs based on BDT- nT-IDs as donors and a fullerene derivative as an acceptor were studied. Among these oligomers, BDT-2T-ID, incorporating bithiophene as the π-bridging units, showed better photovoltaic performance with a maximum power conversion efficiency as high as 6.9% under AM 1.5G illumination without using solvent additives or postdeposition treatments. These favorable properties originated from the well-developed interpenetrating network morphology of BDT-2T-ID, with larger domain sizes in the photoactive layer. Even though all oligomers have the same A-D-A main backbone, structural modulation of the π-bridging nT length was found to impact their self-organization and nanostructure formation in the solid state, as well as the corresponding OSC device performance.

  20. Rhodium-Catalyzed C-C Bond Formation via Heteroatom-Directed C-H Bond Activation

    Energy Technology Data Exchange (ETDEWEB)

    Colby, Denise; Bergman, Robert; Ellman, Jonathan

    2010-05-13

    Once considered the 'holy grail' of organometallic chemistry, synthetically useful reactions employing C-H bond activation have increasingly been developed and applied to natural product and drug synthesis over the past decade. The ubiquity and relative low cost of hydrocarbons makes C-H bond functionalization an attractive alternative to classical C-C bond forming reactions such as cross-coupling, which require organohalides and organometallic reagents. In addition to providing an atom economical alternative to standard cross - coupling strategies, C-H bond functionalization also reduces the production of toxic by-products, thereby contributing to the growing field of reactions with decreased environmental impact. In the area of C-C bond forming reactions that proceed via a C-H activation mechanism, rhodium catalysts stand out for their functional group tolerance and wide range of synthetic utility. Over the course of the last decade, many Rh-catalyzed methods for heteroatom-directed C-H bond functionalization have been reported and will be the focus of this review. Material appearing in the literature prior to 2001 has been reviewed previously and will only be introduced as background when necessary. The synthesis of complex molecules from relatively simple precursors has long been a goal for many organic chemists. The ability to selectively functionalize a molecule with minimal pre-activation can streamline syntheses and expand the opportunities to explore the utility of complex molecules in areas ranging from the pharmaceutical industry to materials science. Indeed, the issue of selectivity is paramount in the development of all C-H bond functionalization methods. Several groups have developed elegant approaches towards achieving selectivity in molecules that possess many sterically and electronically similar C-H bonds. Many of these approaches are discussed in detail in the accompanying articles in this special issue of Chemical Reviews. One approach

  1. Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores

    KAUST Repository

    Zhang, Siyuan

    2017-09-05

    Two intermediate-sized donor molecules, BBTz-X and BDT-X, have been synthesized by the Stille coupling between 4-(4,4-bis(2-ethylhexyl)-6-(trimethylstannyl)-4H-silolo[3,2-b:4,5-b′]dithiophen-2-yl)-7-(5′-hexyl-[2,2′-bithiophen]-5-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine and either 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diiodobenzo[1,2-d:4,5-d′]bis(thiazole) or 2,6-dibromo-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene, respectively. Both oxidation and reduction potentials for BBTz-X are anodically shifted relative to those for BDT-X, but the oxidation potential is more sensitive to the identity of the core; this is consistent with what is seen for DFT-calculated HOMO and LUMO energies and with a slightly blue-shifted absorption maximum for BBTz-X. Although DFT calculations, along with crystal structures of related compounds, suggest more planar molecular structures for BBTz-X than for BDT-X, film structures and the effects of various annealing processes on these films, as revealed by GIWAXS, are similar. The performance of BDT-X:PC61BM bulk-heterojunction solar cells is more sensitive to annealing conditions than that of BBTz-X:PC61BM cells, but under appropriate conditions, both yield power conversion efficiencies of >7%.

  2. Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores

    KAUST Repository

    Zhang, Siyuan; Zhang, Junxiang; Abdelsamie, Maged; Shi, Qinqin; Zhang, Yadong; Parker, Timothy C.; Jucov, Evgheni V.; Timofeeva, Tatiana V.; Amassian, Aram; Bazan, Guillermo C.; Blakey, Simon B.; Barlow, Stephen; Marder, Seth R.

    2017-01-01

    Two intermediate-sized donor molecules, BBTz-X and BDT-X, have been synthesized by the Stille coupling between 4-(4,4-bis(2-ethylhexyl)-6-(trimethylstannyl)-4H-silolo[3,2-b:4,5-b′]dithiophen-2-yl)-7-(5′-hexyl-[2,2′-bithiophen]-5-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine and either 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diiodobenzo[1,2-d:4,5-d′]bis(thiazole) or 2,6-dibromo-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene, respectively. Both oxidation and reduction potentials for BBTz-X are anodically shifted relative to those for BDT-X, but the oxidation potential is more sensitive to the identity of the core; this is consistent with what is seen for DFT-calculated HOMO and LUMO energies and with a slightly blue-shifted absorption maximum for BBTz-X. Although DFT calculations, along with crystal structures of related compounds, suggest more planar molecular structures for BBTz-X than for BDT-X, film structures and the effects of various annealing processes on these films, as revealed by GIWAXS, are similar. The performance of BDT-X:PC61BM bulk-heterojunction solar cells is more sensitive to annealing conditions than that of BBTz-X:PC61BM cells, but under appropriate conditions, both yield power conversion efficiencies of >7%.

  3. Effect of five-membered ring and heteroatom substitution on charge transport properties of perylene discotic derivatives: A theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Amparo, E-mail: anavarro@ujaen.es; Fernández-Liencres, M. Paz; Peña-Ruiz, Tomás; Granadino-Roldán, José M.; Fernández-Gómez, Manuel [Departamento de Química Física y Analítica, Universidad de Jaén, Campus Las Lagunillas, E23071 Jaén (Spain); García, Gregorio [Instituto de Energía Solar and Departamento TFB, E.T.S.I. Telecomunicación, Universidad Politécnica de Madrid, Ciudad Universitaria, Madrid 28040 (Spain)

    2016-08-07

    Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier compared to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials.

  4. Evidence for a hopping mechanism in metal|single molecule|metal junctions involving conjugated metal–terpyridyl complexes; potential-dependent conductances of complexes [M(pyterpy)2]2+(M = Co and Fe; pyterpy = 4′-(pyridin-4-yl)-2,2′:6′,2′′-terpyridine) in ionic liquid

    DEFF Research Database (Denmark)

    Chappell, Sarah; Brooke, Carly; Nichols, Richard John

    2016-01-01

    Extensive studies of various families of conjugated molecules in metal|molecule|metal junctions suggest that the mechanism of conductance is usually tunnelling for molecular lengths < ca. 4 nm, and that for longer molecules, coherence is lost as a hopping element becomes more significant. In this...

  5. Facilitated Oxygen Chemisorption in Heteroatom-Doped Carbon for Improved Oxygen Reaction Activity in All-Solid-State Zinc-Air Batteries.

    Science.gov (United States)

    Liu, Sisi; Wang, Mengfan; Sun, Xinyi; Xu, Na; Liu, Jie; Wang, Yuzhou; Qian, Tao; Yan, Chenglin

    2018-01-01

    Driven by the intensified demand for energy storage systems with high-power density and safety, all-solid-state zinc-air batteries have drawn extensive attention. However, the electrocatalyst active sites and the underlying mechanisms occurring in zinc-air batteries remain confusing due to the lack of in situ analytical techniques. In this work, the in situ observations, including X-ray diffraction and Raman spectroscopy, of a heteroatom-doped carbon air cathode are reported, in which the chemisorption of oxygen molecules and oxygen-containing intermediates on the carbon material can be facilitated by the electron deficiency caused by heteroatom doping, thus improving the oxygen reaction activity for zinc-air batteries. As expected, solid-state zinc-air batteries equipped with such air cathodes exhibit superior reversibility and durability. This work thus provides a profound understanding of the reaction principles of heteroatom-doped carbon materials in zinc-air batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

    International Nuclear Information System (INIS)

    Goldfarb, Jillian L.; Suuberg, Eric M.

    2010-01-01

    The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol -1 were measured over the temperature range of (301 to 486) K using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin, and 9H-pyrido[3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

  7. Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, Jillian L., E-mail: JillianLGoldfarb@gmail.co [Division of Engineering, Brown University, Providence, RI 02912 (United States); Suuberg, Eric M., E-mail: Eric_Suuberg@brown.ed [Division of Engineering, Brown University, Providence, RI 02912 (United States)

    2010-06-15

    The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol{sup -1} were measured over the temperature range of (301 to 486) K using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin, and 9H-pyrido[3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

  8. Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds

    Science.gov (United States)

    Gao, Hongyin; Zhou, Zhe; Kwon, Doo-Hyun; Coombs, James; Jones, Steven; Behnke, Nicole Erin; Ess, Daniel H.; Kürti, László

    2017-07-01

    Arylmetals are highly valuable carbon nucleophiles that are readily and inexpensively prepared from aryl halides or arenes and widely used on both laboratory and industrial scales to react directly with a wide range of electrophiles. Although C-C bond formation has been a staple of organic synthesis, the direct transfer of primary amino (-NH2) and hydroxyl (-OH) groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge because of the absence of suitable heteroatom-transfer reagents. Here, we demonstrate the use of bench-stable N-H and N-alkyl oxaziridines derived from readily available terpenoid scaffolds as efficient multifunctional reagents for the direct primary amination and hydroxylation of structurally diverse aryl- and heteroarylmetals. This practical and scalable method provides one-step synthetic access to primary anilines and phenols at low temperature and avoids the use of transition-metal catalysts, ligands and additives, nitrogen-protecting groups, excess reagents and harsh workup conditions.

  9. An MCBJ case study : The influence of π-conjugation on the single-molecule conductance at a solid/liquid interface

    NARCIS (Netherlands)

    Hong, Wenjing; Valkenier, Hennie; Meszaros, Gabor; Manrique, David Zsolt; Mishchenko, Artem; Putz, Alexander; Garcia, Pavel Moreno; Lambert, Colin J.; Hummelen, Jan C.; Wandlowski, Thomas

    2011-01-01

    π-Conjugation plays an important role in charge transport through single molecular junctions. We describe in this paper the construction of a mechanically controlled break-junction setup (MCBJ) equipped with a highly sensitive log I–V converter in order to measure ultralow conductances of molecular

  10. Role of Nearby Charges on the Electronic Structure of π-Conjugated Molecules: Symmetric versus Asymmetric Charge Distributions in Oligo(p-phenyleneethynylene)

    DEFF Research Database (Denmark)

    Kirketerp, Maj-Britt Suhr; Ryhding, Torben; Støchkel, Kristian

    2011-01-01

    Oligo(p-phenyleneethynylene)s (OPEs) are conjugated oligomers of great interest within materials science and molecular electronics on account of their highly applicable electronic and optical properties. Here we use gas-phase action spectroscopy to elucidate how the intrinsic electronic properties...

  11. Importance of the alignment of polar π conjugated molecules inside carbon nanotubes in determining second-order non-linear optical properties.

    Science.gov (United States)

    Yumura, Takashi; Yamamoto, Wataru

    2017-09-20

    We employed density functional theory (DFT) calculations with dispersion corrections to investigate energetically preferred alignments of certain p,p'-dimethylaminonitrostilbene (DANS) molecules inside an armchair (m,m) carbon nanotube (n × DANS@(m,m)), where the number of inner molecules (n) is no greater than 3. Here, three types of alignments of DANS are considered: a linear alignment in a parallel fashion and stacking alignments in parallel and antiparallel fashions. According to DFT calculations, a threshold tube diameter for containing DANS molecules in linear or stacking alignments was found to be approximately 1.0 nm. Nanotubes with diameters smaller than 1.0 nm result in the selective formation of linearly aligned DANS molecules due to strong confinement effects within the nanotubes. By contrast, larger diameter nanotubes allow DANS molecules to align in a stacking and linear fashion. The type of alignment adopted by the DANS molecules inside a nanotube is responsible for their second-order non-linear optical properties represented by their static hyperpolarizability (β 0 values). In fact, we computed β 0 values of DANS assemblies taken from optimized n × DANS@(m,m) structures, and their values were compared with those of a single DANS molecule. DFT calculations showed that β 0 values of DANS molecules depend on their alignment, which decrease in the following order: linear alignment > parallel stacking alignment > antiparallel stacking alignment. In particular, a linear alignment has a β 0 value more significant than that of the same number of isolated molecules. Therefore, the linear alignment of DANS molecules, which is only allowed inside smaller diameter nanotubes, can strongly enhance their second-order non-linear optical properties. Since the nanotube confinement determines the alignment of DANS molecules, a restricted nanospace can be utilized to control their second-order non-linear optical properties. These DFT findings can assist in the

  12. Toward control of the metal-organic interfacial electronic structure in molecular electronics: a first-principles study on self-assembled monolayers of pi-conjugated molecules on noble metals.

    Science.gov (United States)

    Heimel, Georg; Romaner, Lorenz; Zojer, Egbert; Brédas, Jean-Luc

    2007-04-01

    Self-assembled monolayers (SAMs) of organic molecules provide an important tool to tune the work function of electrodes in plastic electronics and significantly improve device performance. Also, the energetic alignment of the frontier molecular orbitals in the SAM with the Fermi energy of a metal electrode dominates charge transport in single-molecule devices. On the basis of first-principles calculations on SAMs of pi-conjugated molecules on noble metals, we provide a detailed description of the mechanisms that give rise to and intrinsically link these interfacial phenomena at the atomic level. The docking chemistry on the metal side of the SAM determines the level alignment, while chemical modifications on the far side provide an additional, independent handle to modify the substrate work function; both aspects can be tuned over several eV. The comprehensive picture established in this work provides valuable guidelines for controlling charge-carrier injection in organic electronics and current-voltage characteristics in single-molecule devices.

  13. Position for Site-Specific Attachment of a DOTA Chelator to Synthetic Affibody Molecules Has a Different Influence on the Targeting Properties of 68Ga-Compared to 111In-Labeled Conjugates

    Directory of Open Access Journals (Sweden)

    Hadis Honarvar

    2014-12-01

    Full Text Available Affibody molecules, small (7 kDa scaffold proteins, are a promising class of probes for radionuclide molecular imaging. Radiolabeling of Affibody molecules with the positron-emitting nuclide 68Ga would permit the use of positron emission tomography (PET, providing better resolution, sensitivity, and quantification accuracy than single-photon emission computed tomography (SPECT. The synthetic anti-HER2 ZHER2:S1 Affibody molecule was conjugated with DOTA at the N-terminus, in the middle of helix 3, or at the C-terminus. The biodistribution of 68Ga- and 111In-labeled Affibody molecules was directly compared in NMRI nu/nu mice bearing SKOV3 xenografts. The position of the chelator strongly influenced the biodistribution of the tracers, and the influence was more pronounced for 68Ga-labeled Affibody molecules than for the 111In-labeled counterparts. The best 68Ga-labeled variant was 68Ga-[DOTA-A1]-ZHER2:S1 which provided a tumor uptake of 13 ± 1 %ID/g and a tumor to blood ratio of 39 ± 12 at 2 hours after injection. 111In-[DOTA-A1]-ZHER2:S1 and 111In-[DOTA-K58]-ZHER2:S1 were equally good at this time point, providing a tumor uptake of 15 to 16 %ID/g and a tumor to blood ratio in the range of 60 to 80. In conclusion, the selection of the best position for a chelator in Affibody molecules can be used for optimization of their imaging properties. This may be important for the development of Affibody-based and other protein-based imaging probes.

  14. Effects of structure and number of heteroatom on the π-π stacking inte-ractions of benzene with N-substituted coronenes: A theoretical study

    Directory of Open Access Journals (Sweden)

    Pouya Karimi

    2014-07-01

    Full Text Available Stability of the π-π stacking interactions in the Ben||N-substituted-coronene complexes was stu-died using the computational quantum chemistry methods (where Ben is benzene and || denotes π-π stacking interaction, and N-substituted-coronene is coronene molecule which substituted with different number of N atoms. The results reveal simultaneous effects of structure and number of Heteroatom on the π-π stacking interactions with N-substituted-coronenes. Changing the number of Heteroatom N in N-substituted-coronenes and substitution of 8N-coronene with electron-withdrawing or electron-donating X groups alter the electron charge density at rings of this molecule and leads to different binding energies in the Ben||X-8N-substituted-coronene com-plexes. Results indicate that electron-withdrawing groups lead to higher π–π stacking binding energies compared to electron-donating ones in the Ben||X-8N-substituted-coronene complexes.

  15. Catalase and superoxide dismutase conjugated with platelet-endothelial cell adhesion molecule antibody distinctly alleviate abnormal endothelial permeability caused by exogenous reactive oxygen species and vascular endothelial growth factor.

    Science.gov (United States)

    Han, Jingyan; Shuvaev, Vladimir V; Muzykantov, Vladimir R

    2011-07-01

    Reactive oxygen species (ROS) superoxide anion (O(2)()) and hydrogen peroxide (H(2)O(2)) produced by activated leukocytes and endothelial cells in sites of inflammation or ischemia cause endothelial barrier dysfunction that may lead to tissue edema. Antioxidant enzymes (AOEs) catalase and superoxide dismutase (SOD) conjugated with antibodies to platelet-endothelial cell adhesion molecule-1 (PECAM-1) specifically bind to endothelium, quench the corresponding ROS, and alleviate vascular oxidative stress and inflammation. In the present work, we studied the effects of anti-PECAM/catalase and anti-PECAM/SOD conjugates on the abnormal permeability manifested by transendothelial electrical resistance decline, increased fluorescein isothiocyanate-dextran influx, and redistribution of vascular endothelial-cadherin in human umbilical vein endothelial cell (HUVEC) monolayers. Anti-PECAM/catalase protected HUVEC monolayers against H(2)O(2)-induced endothelial barrier dysfunction. Polyethylene glycol-conjugated catalase exerted orders of magnitude lower endothelial uptake and no protective effect, similarly to IgG/catalase. Anti-PECAM/catalase, but not anti-PECAM/SOD, alleviated endothelial hyperpermeability caused by exposure to hypoxanthine/xanthine oxidase, implicating primarily H(2)O(2) in the disruption of the endothelial barrier in this model. Thrombin-induced endothelial permeability was not affected by treatment with anti-PECAM/AOEs or the NADPH oxidase inhibitor apocynin or overexpression of AOEs, indicating that the endogenous ROS play no key role in thrombin-mediated endothelial barrier dysfunction. In contrast, anti-PECAM/SOD, but not anti-PECAM/catalase, inhibited a vascular endothelial growth factor (VEGF)-induced increase in endothelial permeability, identifying a key role of endogenous O(2)() in the VEGF-mediated regulation of endothelial barrier function. Therefore, AOEs targeted to endothelial cells provide versatile molecular tools for testing the roles of

  16. Theoretical Investigations of the Photophysical Properties of Star-Shaped π-Conjugated Molecules with Triarylboron Unit for Organic Light-Emitting Diodes Applications

    Directory of Open Access Journals (Sweden)

    Ruifa Jin

    2017-10-01

    Full Text Available The density functional theory (DFT and time-dependent DFT (TD-DFT methodologies have been applied to explore on a series of star-shaped π-conjugated organoboron systems for organic light-emitting diode (OLED materials. The compounds under investigation consist of benzene as π-bridge and different core units and triarylboron end groups. Their geometry structures, frontier molecular orbital (FMO energies, absorption and fluorescence spectra, and charge transport properties have been investigated systematically. It turned out that the FMO energy levels, the band gaps, and reorganization energies optical are affected by the introduction of different core units and triarylboron end groups. The results suggest that the designed compounds are expected to be promising candidates for luminescent materials. Furthermore, they can also serve as hole and/or electron transport materials for OLEDs.

  17. Yeast Cells-Derived Hollow Core/Shell Heteroatom-Doped Carbon Microparticles for Sustainable Electrocatalysis

    Czech Academy of Sciences Publication Activity Database

    Huang, X.; Zou, X.; Meng, Y.; Mikmeková, Eliška; Chen, H.; Voiry, D.; Goswami, A.; Chhowalla, M.; Asefa, T.

    2015-01-01

    Roč. 7, č. 3 (2015), s. 1978-1986 ISSN 1944-8244 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : yeast * heteroatom-doped carbon * oxygen reduction * ORR * hydrazine electrooxidation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 7.145, year: 2015

  18. Chemical Preparation of Graphene Materials Results in Extensive Unintentional Doping with Heteroatoms and Metals

    Czech Academy of Sciences Publication Activity Database

    Chua, C. K.; Ambrosi, A.; Sofer, Z.; Macková, Anna; Havránek, Vladimír; Tomandl, Ivo; Pumera, M.

    2014-01-01

    Roč. 20, č. 48 (2014), s. 15760-15767 ISSN 1521-3765 R&D Projects: GA MŠk(XE) LM2011019; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : doping * graphene * heteroatoms * oxidation * synthetic methods Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  19. Self-assembled nanoparticles based on PEGylated conjugated polyelectrolyte and drug molecules for image-guided drug delivery and photodynamic therapy.

    Science.gov (United States)

    Yuan, Youyong; Liu, Bin

    2014-09-10

    A drug delivery system based on poly(ethylene glycol) (PEG) grafted conjugated polyelectrolyte (CPE) has been developed to serve as a polymeric photosensitizer and drug carrier for combined photodynamic and chemotherapy. The amphiphilic brush copolymer can self-assemble into micellar nanopaticles (NPs) in aqueous media with hydrophobic conjugated polyelectrolyte backbone as the core and hydrophilic PEG as the shell. The NPs have an average diameter of about 100 nm, with the absorption and emission maxima at 502 and 598 nm, respectively, making them suitable for bioimaging applications. Moreover, the CPE itself can serve as a photosensitizer, which makes the NPs not only a carrier for drug but also a photosensitizing unit for photodynamic therapy, resulting in the combination of chemo- and photodynamic therapy for cancer. The half-maximal inhibitory concentration (IC50) value for the combination therapy to U87-MG cells is 12.7 μg mL(-1), which is much lower than that for the solely photodynamic therapy (25.5 μg mL(-1)) or chemotherapy (132.8 μg mL(-1)). To improve the tumor specificity of the system, cyclic arginine-glycine-aspartic acid (cRGD) tripeptide as the receptor to integrin αvβ3 overexpressed cancer cells was further incorporated to the surface of the NPs. The delivery system based on PEGylated CPE is easy to fabricate, which integrates the merits of targeted cancer cell image, chemotherapeutic drug delivery, and photodynamic therapy, making it promising for cancer treatment.

  20. Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue.

    Science.gov (United States)

    Wang, Yanfang; Yang, Na; Liu, Yi

    2018-04-05

    A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560nm. The detection limit for phosphorylated proteins was estimated to be 100nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. New naphtho[1,2-b:5,6-b‧]difuran based two-dimensional conjugated small molecules for photovoltaic application

    Science.gov (United States)

    Peng, Hongjian; Luan, Xiangfeng; Qiu, Lixia; Li, Hang; Liu, Ye; Zou, Yingping

    2017-10-01

    Two new A-D-A small molecules with alkoxyphenyl and alkylthiophenyl-substituted naphtho[1,2-b:5,6-b‧]difuran (NDF) as the central building block named NDFPO-DPP and NDFPS-DPP were synthesized and firstly used as donor materials in organic solar cells (OSCs). The effects of the alkoxyphenyl and alkylthiophenyl side chains on the NDF unit have been investigated. With a single atom variation from O to S, NDFPS-DPP exhibited lower HOMO energy levels than its counterpart NDFPO-DPP, which resulted in enhanced Voc. The device based on NDFPO-DPP with thermal annealing exhibited a better PCE of 3.10% due to the higher and more balanced hole and electron mobilities. The investigations show that NDF could be a promising building block in OSCs via rational molecular structure design and device optimizations.

  2. Bimetallic promotion of cooperative hydrogen transfer and heteroatom removal in coal liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Eisch, J.J.

    1992-04-07

    The ultimate objective of this research has been to uncover novel reagents and experimental conditions for heteroatom removal and hydrogen transfer processes, which would be applicable to the liquefaction of coal under low-severity conditions. To this end, one phase of this research has investigated the cleavage of carbon-heteroatom bonds involving sulfur, oxygen, nitrogen and halogen by subvalent transition-metal complexes. A second phase of the study has assessed the capability of the same transition-metal complexes or of organoaluminum Lewis acids to catalyze the cleavage of carbon-hydrogen bonds in aromatics and hence to promote hydrogen shuttling. Finally, a third phase of our work has uncovered a remarkable synergistic effect of combinations of transition metals with organoaluminum Lewis acids on hydrogen shuttling between aromatics and hydroaromatics. (VC)

  3. Gold nanoparticles on OMS-2 for heterogeneously catalyzed aerobic oxidative α,β-dehydrogenation of β-heteroatom-substituted ketones.

    Science.gov (United States)

    Yoshii, Daichi; Jin, Xiongjie; Yatabe, Takafumi; Hasegawa, Jun-Ya; Yamaguchi, Kazuya; Mizuno, Noritaka

    2016-12-06

    In the presence of Au nanoparticles supported on manganese oxide OMS-2 (Au/OMS-2), various kinds of β-heteroatom-substituted α,β-unsaturated ketones (heteroatom = N, O, S) can be synthesized through α,β-dehydrogenation of the corresponding saturated ketones using O 2 (in air) as the oxidant. The catalysis of Au/OMS-2 is truly heterogeneous, and the catalyst can be reused.

  4. Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

    OpenAIRE

    Zdanowska Sandra; Pyzalska Magdalena; Drabowicz Józef; Kulawik Damian; Pavlyuk Volodymyr; Girek Tomasz; Ciesielski Wojciech

    2016-01-01

    This paper concentrates on electrochemical properties of groups of multi-walled carbon nanotubes (MWCNT) functionalized with substituents containing a stereogenic heteroatom bonded covalently to the surface of the carbon nanotube. This system was tested in Swagelok-type cells. The cells comprised a system (functionalized CNT with salts containing S and P atoms) with a working electrode, microfiber separators soaked with electrolyte solution, and a lithium foil counter/reference (commercial Li...

  5. Heteroatom-doped porous carbon from methyl orange dye wastewater for oxygen reduction

    Directory of Open Access Journals (Sweden)

    Yiqing Wang

    2018-04-01

    Full Text Available Banana peel-derived porous carbon (BPPC was prepared from banana peel and used as an adsorbent for methyl orange (MO wastewater removal. BPPC-MO50 is a N,S-doped BPPC obtained via secondary carbonization. The BPPC-MO50 exhibited a high specific surface area of 1774.3 m2/g. Heteroatom-doped porous carbon (PC was successfully synthesized from the BPPC absorbed MO at high temperature and used for oxygen reduction. The BPPC-MO50 displayed the highest ORR onset potential among all carbon-based electrocatalysts, i.e., 0.93 V vs. reversible hydrogen electrode (RHE. This is the first report to describe porous carbon-activated materials from agriculture and forestry waste that is used for adsorption of dyes from wastewater via an enhanced heteroatom (N,S content. These results may contribute to the sustainable development of dye wastewater treatment by transforming saturated PC into an effective material and has potential applications in fuel cells or as energy sources. Keywords: Banana peel, Dye wastewater, Porous carbon, Heteroatom doping, Oxygen reduction reaction

  6. Persistence Mechanisms of Conjugative Plasmids

    DEFF Research Database (Denmark)

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

    2009-01-01

    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 suc...

  7. Neighboring Hetero-Atom Assistance of Sacrificial Amines to Hydrogen Evolution Using Pt-Loaded TiO2-Photocatalyst

    Directory of Open Access Journals (Sweden)

    Masahide Yasuda

    2014-05-01

    Full Text Available Photocatalytic H2 evolution was examined using Pt-loaded TiO2-photocatalyst in the presence of amines as sacrificial agents. In the case of amines with all of the carbon attached to the hetero-atom such as 2-aminoethanol, 1,2-diamonoethane, 2-amino-1,3-propanediol, and 3-amino-1,2-propanediol, they were completely decomposed into CO2 and water to quantitatively evolve H2. On the other hand, the amines with both hetero-atoms and one methyl group at the β-positions (neighboring carbons of amino group such as 2-amino-1-propanol and 1,2-diaminopropane were partially decomposed. Also, the photocatalytic H2 evolution using amines without the hetero-atoms at the β-positions such as ethylamine, propylamine, 1-butylamine, 1,3-diaminopropane, 2-propylamine, and 2-butylamine was inefficient. Thus, it was found that the neighboring hetero-atom strongly assisted the degradation of sacrificial amines. Moreover, rate constants for H2 evolution were compared among amines. In conclusion, the neighboring hetero-atom did not affect the rate constants but enhanced the yield of hydrogen evolution.

  8. Upgrading including heteroatom removal from Victorian brown coal-derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Larkins, F.P.; Youings, J.C.; Jackson, W.R.; Park, D. (University of Tasmania, Hobart, Tasmania (Australia))

    1989-10-01

    It has been shown using model compounds that the hydrodeoxygenation performance of a catalyst is severely inhibited by the presence of nitrogen-containing compounds under conditions of moderate reaction severity. For a low molecular weight coal-derived liquid commercial catalysts were effective for HDO and HDN at 400{degree}C, 10 MPa H{sub 2} for 30 min reaction time. For a coal-derived liquid high in asphaltene commercial catalysts and others prepared and tested in this study were ineffective. Alternative catalysts and hydrotreating conditions of greater severity will be required for such materials to effect acceptable heteroatom removal. 3 refs., 2 figs., 2 tabs.

  9. The Effects of Heteroatoms Si and S on Tuning the Optical Properties of Rhodamine- and Fluorescein-Based Fluorescence Probes: A Theoretical Analysis.

    Science.gov (United States)

    Zhou, Panwang; Ning, Cai; Alsaedi, Ahmed; Han, Keli

    2016-10-05

    The effects of the incorporated heteroatoms Si and S on tuning the optical properties of rhodamine- and fluorescein-based fluorescence probes is investigated using DFT and time-dependent DFT with four different functionals. As previously proposed, the large redshift (90 nm) produced by a Si atom in both the absorption and emission spectra can be attributed to the σ*-π* conjugation between the σ* orbital of the Si atom and the π* orbital of the adjacent carbon atoms. However, the presence of a Si atom does not alter the fluorescence quenching mechanism of the nonfluorescent forms of the investigated compounds. For the first time, these theoretical results indicate that the n orbital of the S atom plays an important role in determining the optical properties of the nonfluorescent form of rhodamine-based fluorescence probes. It alters the fluorescence quenching mechanism by lowering the energy of the dark nπ* state, which is due to breakage of the C10-S52 bond upon photoexcitation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Sodium-ion supercapacitors based on nanoporous pyroproteins containing redox-active heteroatoms

    Science.gov (United States)

    Cho, Se Youn; Yoon, Hyeon Ji; Kim, Na Rae; Yun, Young Soo; Jin, Hyoung-Joon

    2016-10-01

    Nanostructured carbon-based materials fabricated via simple methods from renewable bio-resources have great potential in rechargeable energy storage systems. In this study, nanoporous pyroproteins containing a large amount of redox-active heteroatoms (H-NPs) were fabricated from silk fibroin by an in situ carbonization/activation method. The H-NPs have a large surface area of ∼3050 m2 g-1, which is mainly comprised of nanometer-scale pores. Also, these H-NPs have oxygen and nitrogen heteroatoms of 17.4 wt% and 2.9 wt%, respectively. Synergistic sodium ion storage behaviors originate from electrochemical double layer capacitance and pseudocapacitance, leading to very high electrochemical performances of H-NPs in aqueous and non-aqueous electrolyte systems. Sodium-ion supercapacitors (NISs) based on commercial graphite//H-NPs show a high specific power of ∼1900 W kg-1 at ∼77 Wh kg-1. Also, NISs based on commercial hard carbon//H-NPs exhibit a high specific energy of ∼217 Wh kg-1 at ∼42 W kg-1. In addition, outstanding cycling performances over 30,000 cycles are achieved for symmetric NISs.

  11. Micro-orientation control of silicon polymer thin films on graphite surfaces modified by heteroatom doping

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Iwao, E-mail: shimoyama.iwao@jaea.go.jp [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Baba, Yuji [Fukushima Administrative Department, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Hirao, Norie [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan)

    2017-05-31

    Highlights: • Micro-orientation control method for organic polysilane thin films is proposed. • This method utilizes surface modification of graphite using heteroatom doping. • Lying, standing, and random orientations can be freely controlled by this method. • Micro-pattering of a polysilane film with controlled orientations is achieved. - Abstract: Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is applied to study orientation structures of polydimethylsilane (PDMS) films deposited on heteroatom-doped graphite substrates prepared by ion beam doping. The Si K-edge NEXAFS spectra of PDMS show opposite trends of polarization dependence for non irradiated and N{sub 2}{sup +}-irradiated substrates, and show no polarization dependence for an Ar{sup +}-irradiated substrate. Based on a theoretical interpretation of the NEXAFS spectra via first-principles calculations, we clarify that PDMS films have lying, standing, and random orientations on the non irradiated, N{sub 2}{sup +}-irradiated, and Ar{sup +}-irradiated substrates, respectively. Furthermore, photoemission electron microscopy indicates that the orientation of a PDMS film can be controlled with microstructures on the order of μm by separating irradiated and non irradiated areas on the graphite surface. These results suggest that surface modification of graphite using ion beam doping is useful for micro-orientation control of organic thin films.

  12. Heteroatom Doped-Carbon Nanospheres as Anodes in Lithium Ion Batteries.

    Science.gov (United States)

    Pappas, George S; Ferrari, Stefania; Huang, Xiaobin; Bhagat, Rohit; Haddleton, David M; Wan, Chaoying

    2016-01-09

    Long cycle performance is a crucial requirement in energy storage devices. New formulations and/or improvement of "conventional" materials have been investigated in order to achieve this target. Here we explore the performance of a novel type of carbon nanospheres (CNSs) with three heteroatom co-doped (nitrogen, phosphorous and sulfur) and high specific surface area as anode materials for lithium ion batteries. The CNSs were obtained from carbonization of highly-crosslinked organo (phosphazene) nanospheres (OPZs) of 300 nm diameter. The OPZs were synthesized via a single and facile step of polycondensation reaction between hexachlorocyclotriphosphazene (HCCP) and 4,4'-sulphonyldiphenol (BPS). The X-ray Photoelectron Spectroscopy (XPS) analysis showed a high heteroatom-doping content in the structure of CNSs while the textural evaluation from the N₂ sorption isotherms revealed the presence of micro- and mesopores and a high specific surface area of 875 m²/g. The CNSs anode showed remarkable stability and coulombic efficiency in a long charge-discharge cycling up to 1000 cycles at 1C rate, delivering about 130 mA·h·g -1 . This study represents a step toward smart engineering of inexpensive materials with practical applications for energy devices.

  13. Heteroatom Doped-Carbon Nanospheres as Anodes in Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    George S. Pappas

    2016-01-01

    Full Text Available Long cycle performance is a crucial requirement in energy storage devices. New formulations and/or improvement of “conventional” materials have been investigated in order to achieve this target. Here we explore the performance of a novel type of carbon nanospheres (CNSs with three heteroatom co-doped (nitrogen, phosphorous and sulfur and high specific surface area as anode materials for lithium ion batteries. The CNSs were obtained from carbonization of highly-crosslinked organo (phosphazene nanospheres (OPZs of 300 nm diameter. The OPZs were synthesized via a single and facile step of polycondensation reaction between hexachlorocyclotriphosphazene (HCCP and 4,4′-sulphonyldiphenol (BPS. The X-ray Photoelectron Spectroscopy (XPS analysis showed a high heteroatom-doping content in the structure of CNSs while the textural evaluation from the N2 sorption isotherms revealed the presence of micro- and mesopores and a high specific surface area of 875 m2/g. The CNSs anode showed remarkable stability and coulombic efficiency in a long charge–discharge cycling up to 1000 cycles at 1C rate, delivering about 130 mA·h·g−1. This study represents a step toward smart engineering of inexpensive materials with practical applications for energy devices.

  14. Linking the Molecular Signature of Heteroatomic Dissolved Organic Matter to Watershed Characteristics in World Rivers.

    Science.gov (United States)

    Wagner, Sasha; Riedel, Thomas; Niggemann, Jutta; Vähätalo, Anssi V; Dittmar, Thorsten; Jaffé, Rudolf

    2015-12-01

    Large world rivers are significant sources of dissolved organic matter (DOM) to the oceans. Watershed geomorphology and land use can drive the quality and reactivity of DOM. Determining the molecular composition of riverine DOM is essential for understanding its source, mobility and fate across landscapes. In this study, DOM from the main stem of 10 global rivers covering a wide climatic range and land use features was molecularly characterized via ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). FT-ICR mass spectral data revealed an overall similarity in molecular components among the rivers. However, when focusing specifically on the contribution of nonoxygen heteroatomic molecular formulas (CHON, CHOS, CHOP, etc.) to the bulk molecular signature, patterns relating DOM composition and watershed land use became apparent. Greater abundances of N- and S-containing molecular formulas were identified as unique to rivers influenced by anthropogenic inputs, whereas rivers with primarily forested watersheds had DOM signatures relatively depleted in heteroatomic content. A strong correlation between cropland cover and dissolved black nitrogen was established when focusing specifically on the pyrogenic class of compounds. This study demonstrated how changes in land use directly affect downstream DOM quality and could impact C and nutrient cycling on a global scale.

  15. Formation, Energetics, and Electronic Properties of Graphene Monolayer and Bilayer Doped with Heteroatoms

    Directory of Open Access Journals (Sweden)

    Yoshitaka Fujimoto

    2015-01-01

    Full Text Available Doping with heteroatoms is one of the most effective methods to tailor the electronic properties of carbon nanomaterials such as graphene and carbon nanotubes, and such nanomaterials doped with heteroatom dopants might therefore provide not only new physical and chemical properties but also novel nanoelectronics/optoelectronics device applications. The boron and nitrogen are neighboring elements to carbon in the periodic table, and they are considered to be good dopants for carbon nanomaterials. We here review the recent work of boron and nitrogen doping effects into graphene monolayer as well as bilayer on the basis of the first-principles electronic structure calculations in the framework of the density-functional theory. We show the energetics and the electronic properties of boron and nitrogen defects in graphene monolayer and bilayer. As for the nitrogen doping, we further discuss the stabilities, the growth processes, and the electronic properties associated with the plausible nitrogen defect formation in graphene which is suggested by experimental observations.

  16. Alkaloid-derived molecules in low rank Argonne premium coals.

    Energy Technology Data Exchange (ETDEWEB)

    Winans, R. E.; Tomczyk, N. A.; Hunt, J. E.

    2000-11-30

    Molecules that are probably derived from alkaloids have been found in the extracts of the subbituminous and lignite Argonne Premium Coals. High resolution mass spectrometry (HRMS) and liquid chromatography mass spectrometry (LCMS) have been used to characterize pyridine and supercritical extracts. The supercritical extraction used an approach that has been successful for extracting alkaloids from natural products. The first indication that there might be these natural products in coals was the large number of molecules found containing multiple nitrogen and oxygen heteroatoms. These molecules are much less abundant in bituminous coals and absent in the higher rank coals.

  17. Structure Property Relationships in Organic Conjugated Systems

    OpenAIRE

    O'Neill, Luke; Lynch, Patrick; McNamara, Mary

    2005-01-01

    A series of π conjugated oligomers were studied by absorption and photoluminescence spectroscopy. A linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transition energies, it was observed that the Sto...

  18. High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage

    Directory of Open Access Journals (Sweden)

    Zhijie Wang

    2018-04-01

    Full Text Available In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S doping of 0.9% and nitrogen (N doping of as high as 15.5%, in which the electrochemically active N accounts for 84% of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g−1, it still delivers a high discharge capacity of 329 mA h g−1 after 1,000 cycles. First principle calculations verifies that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes.

  19. Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

    Directory of Open Access Journals (Sweden)

    Zdanowska Sandra

    2016-12-01

    Full Text Available This paper concentrates on electrochemical properties of groups of multi-walled carbon nanotubes (MWCNT functionalized with substituents containing a stereogenic heteroatom bonded covalently to the surface of the carbon nanotube. This system was tested in Swagelok-type cells. The cells comprised a system (functionalized CNT with salts containing S and P atoms with a working electrode, microfiber separators soaked with electrolyte solution, and a lithium foil counter/reference (commercial LiCoO2 electrode. The electrolyte solution was 1 M LiPF6 in propylene carbonate. Using standard techniques (cyclic voltammetry/chronopotentiometry, galvanostatic cycling was performed on the cells at room temperature with a CH Instruments Model 600E potentiostat/galvanostat electrochemical measurements. Methods of functionalization CNT were compared in terms of the electrochemical properties of the studied systems. In all systems, the process of charge/discharge was observed.

  20. Adsorption of alanine with heteroatom substituted fullerene for solar cell application: A DFT study.

    Science.gov (United States)

    Dheivamalar, S; Sugi, L; Ravichandran, K; Sriram, S

    2018-05-14

    C 20 is the most important fullerene cage and alanine is the simplest representation of a backbone unit of the protein. The absorption feasibility of alanine molecule in the Si-doped C 20 and B-doped C 20 fullerenes has been studied based on calculated electronic properties of fullerenes using density functional theory (DFT). In this work, we explore the ability of Si-doped C 20 , B-doped C 20 fullerene to interact with alanine at the DFT-B3LYP/6-31G, RHF level of theory. We find that noticeable structural change takes place in C 20 when one of its carbon is substituted with Si or B. The molecular geometry, electronic properties and vibrational analysis have also been performed on the title compounds. The NMR study reveals the aromaticity of the pure and doped fullerene compounds. Stability of the doped fullerene - alanine compound arises from hyper conjugative interactions. It leads to one of the major property of bioactivity, charge transfer and delocalization of charge and this properties has been analyzed using Natural Bond Orbital (NBO) analysis. The energy gap of the doped fullerene reveals that there is a decrease in the size of energy gap significantly, making them more reactive as compared to C 20 fullerene. Theoretical studies of the electronic spectra by using time - dependent density functional theory (TD-DFT) method were helpful to interpret the observed electronic transition state. We aim to optimize the performance of the solar cells by altering the frontier orbital energy gaps. Considering all studied properties, it may be inferred that the applicability of C 20 fullerene as the non-linear optical (NLO) material and its NLO property would increase on doping fullerene with Si and B atom. Specifically C 19 Si would be better among them. Copyright © 2018. Published by Elsevier B.V.

  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

    . 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......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...

  2. Carbazole based electrochromic polymers with benzoazole units: Effect of heteroatom variation on electrochromic performance

    Directory of Open Access Journals (Sweden)

    C. Doyranli

    2016-09-01

    Full Text Available A series of carbazole-based polymers were synthesized via Suzuki polymerization between N-(2-ethylhexylcarbazole-3,6-bis(ethyleneboronate (Cbz and dibromobenzazole unit. Three different polymers, PCBN, PCBS and PCBSe were obtained from 4,7-dibromo-2-hexyl-2H-benzotriazole (BN, 4,7-dibromo-2,1,3-benzothiadiazole- (BS and 4,7-dibromo-2,1,3-benzoselenadiazole (BSe, respectively. It is observed that, the variation of heteroatoms (N,S and Se on the benzazole unit have most important effect on electro-optic properties of the PCBX polymers. Neutral state color of the polymer films and their electrochromic performances are also influenced. Among the synthesized polymers, the PCBS bearing 2,1,3-benzothiadiazole as acceptor units has a broad absorption and 50% of ΔT in the near-IR regime at the oxidized state. This property of PCBS is a great advantage for near-IR electrochromic applications.

  3. Fluorescent probe based on heteroatom containing styrylcyanine: pH-sensitive properties and bioimaging in vivo

    International Nuclear Information System (INIS)

    Yang, Xiaodong; Gao, Ya; Huang, Zhibing; Chen, Xiaohui; Ke, Zhiyong; Zhao, Peiliang; Yan, Yichen; Liu, Ruiyuan; Qu, Jinqing

    2015-01-01

    A novel fluorescent probe based on heteroatom containing styrylcyanine is synthesized. The fluorescence of probe is bright green in basic and neutral media but dark orange in strong acidic environments, which could be reversibly switched. Such behavior enables it to work as a fluorescent pH sensor in the solution state and a chemosensor for detecting acidic and basic volatile organic compounds. Analyses by NMR spectroscopy confirm that the protonation or deprotonation of pyridinyl moiety is responsible for the sensing process. In addition, the fluorescent microscopic images of probe in live cells and zebrafish are achieved successfully, suggesting that the probe has good cell membrane permeability and low cytotoxicity. - Graphical abstract: A novel styrylcyanine-based fluorescent pH probe was designed and synthesized, the fluorescence of which is bright green in basic and neutral media but dark orange in strong acidic environments. Such behavior enables it to work as a fluorescent pH sensor in solution states, and a chemosensor for detecting volatile organic compounds with high acidity and basicity in solid state. In addition, it can be used for fluorescent imaging in living cell and living organism. - Highlights: • Bright green fluorescence was observed in basic and neutral media. • Dark orange fluorescence was found in strong acidic environments. • Volatile organic compounds with high acidity and basicity could be detected. • Bioimaging in living cell and living organism was achieved successfully

  4. Hierarchically porous and heteroatom doped carbon derived from tobacco rods for supercapacitors

    Science.gov (United States)

    Zhao, Yong-Qing; Lu, Min; Tao, Peng-Yu; Zhang, Yun-Jie; Gong, Xiao-Ting; Yang, Zhi; Zhang, Guo-Qing; Li, Hu-Lin

    2016-03-01

    A novel tobacco rods-derived carbon (TC) has been prepared by hydrothermal carbonization and potassium hydroxide activation strategy for supercapacitors application. The physicochemical properties of TC are investigated by X-ray diffraction, Raman spectra, Scanning electron microscopy, Nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and four-probe tests. Results show TC derived from different tobacco rods possesses similar properties, such as amorphous state, high specific surface area, hierarchical porous structure, numerous heteroatom groups, and good electrical conductivity. The electrochemical characteristics of TC are examined via cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements. In a three-electrode system, TC exhibits high capacitance with 286.6 F g-1 at 0.5 A g-1, excellent rate performance with 212.1 F g-1 even at 30 A g-1, and outstanding cyclic stability with 96% capacitance retention after 10,000 cycles at 5 A g-1. Furthermore, TC supercapacitor devices can deliver an energy density of 31.3 Wh kg-1 at 0.5 A g-1 and power density of 11.8 kW kg-1 at 15 A g-1. Therefore, this novel concept of tobacco use, namely tobacco rods from cigarette (the harmful) to high-performance carbon for supercapacitors (the beneficial), is an extremely promising strategy for developing high-performance carbon from renewable sources, and supporting the tobacco control.

  5. X-ray photoelectron spectroscopy of graphitic carbon nanomaterials doped with heteroatoms

    Directory of Open Access Journals (Sweden)

    Toma Susi

    2015-01-01

    Full Text Available X-ray photoelectron spectroscopy (XPS is one of the best tools for studying the chemical modification of surfaces, and in particular the distribution and bonding of heteroatom dopants in carbon nanomaterials such as graphene and carbon nanotubes. Although these materials have superb intrinsic properties, these often need to be modified in a controlled way for specific applications. Towards this aim, the most studied dopants are neighbors to carbon in the periodic table, nitrogen and boron, with phosphorus starting to emerge as an interesting new alternative. Hundreds of studies have used XPS for analyzing the concentration and bonding of dopants in various materials. Although the majority of works has concentrated on nitrogen, important work is still ongoing to identify its precise atomic bonding configurations. In general, care should be taken in the preparation of a suitable sample, consideration of the intrinsic photoemission response of the material in question, and the appropriate spectral analysis. If this is not the case, incorrect conclusions can easily be drawn, especially in the assignment of measured binding energies into specific atomic configurations. Starting from the characteristics of pristine materials, this review provides a practical guide for interpreting X-ray photoelectron spectra of doped graphitic carbon nanomaterials, and a reference for their binding energies that are vital for compositional analysis via XPS.

  6. Preparation and biodistribution study of 99Tcm labelled dextran conjugates

    International Nuclear Information System (INIS)

    Yang Chunhui; Li Hongyu; Liang Jixin; Lu Jia; Luo Hongyi; Zheng Deqiang; Sun Guiquan

    2012-01-01

    99 Tc m Mannosylated dextran conjugates were prepared through [ 99 Tc m (CO) 3 ] + precursor synthesized by carbonyl Isolink kit. The labelled conjugates were injected sub-dermally into the rear foots of the mice, and the patent blue solution was injected at the same site 10 min before sacrifice. The mice were killed at 1 h and 4 h postinjection, and the samples of different tissues including SLN, 2LN, injection site, liver, spleen, blood were dissected and counted. The uptake in terms was calculated. The results of biodistribution demonstrated that the SLN uptakes of radiopharmaceutical (without mannose in the molecules) were rather low and in vivo excretion of these conjugates were comparatively faster, and the uptake of injection site was also low; on the other hand, the SLN uptakes of radio pharmaceutical (with mannose in their molecules) were much higher than those of their corresponding dextran conjugates without mannose, but the retention in the injection site of these conjugates increased too. The results indicated that the affinity of mannosyl-dextran conjugates to the receptors on the surface of macrophages in the lymph node. In addition, the different relative molecular mass of dextran conjugates also cause different biodistribution results, the major one had higher SLN uptake, the difference was significant (P 99 Tc m (CO) 3 ] + labelled mannosylated dextran conjugates showed promising properties as SLN imaging agent and worth further investigation. (authors)

  7. Optical phase conjugation

    CERN Document Server

    Fisher, Robert A

    1983-01-01

    This book appears at a time of intense activity in optical phase conjugation. We chose not to await the maturation of the field, but instead to provide this material in time to be useful in its development. We have tried very hard to elucidate and interrelate the various nonlinear phenomena which can be used for optical phase conjugation.

  8. Methotrexate and epirubicin conjugates as potential antitumor drugs

    Directory of Open Access Journals (Sweden)

    Szymon Wojciech Kmiecik

    2017-07-01

    Full Text Available Introduction: The use of hybrid molecules has become one of the most significant approaches in new cytotoxic drug design. This study describes synthesis and characterization of conjugates consisting of two well-known and characterized chemotherapeutic agents: methotrexate (MTX and epirubicin (EPR. The synthesized conjugates combine two significant anticancer strategies: combinatory therapy and targeted therapy. These two drugs were chosen because they have different mechanisms of action, which can increase the anticancer effect of the obtained conjugates. MTX, which is a folic acid analog, has high cytotoxic properties and can serve as a targeting moiety that can reach folate receptors (FRs overexpresing tumor cells. Combination of nonselective drugs such as EPR with MTX can increase the selectivity of the obtained conjugates, while maintaining the high cytotoxic properties.Materials and methods: Conjugates were purified by RP-HPLC and the structure was investigated by MS and MS/MS methods. The effect of the conjugates on proliferation of LoVo, LoVo/Dx, MCF-7 and MV-4-11 human cancer cell lines was determined by SRB or MTT assay.Results: The conjugation reaction results in the formation of monosubstituted (α, γ and disubstituted MTX derivatives. In vitro proliferation data demonstrate that the conjugates synthesized in our study show lower cytotoxic properties than both chemotherapeutics used alone.Discussion: Epirubicin cytotoxicity was not observed in obtained conjugates. Effective drugs release after internalization needs further investigation.

  9. Conjugation vs hyperconjugation in molecular structure of acrolein

    Science.gov (United States)

    Shishkina, Svitlana V.; Slabko, Anzhelika I.; Shishkin, Oleg V.

    2013-01-01

    Analysis of geometric parameters of butadiene and acrolein reveals the contradiction between the Csp2-Csp2 bond length in acrolein and classical concept of conjugation degree in the polarized molecules. In this Letter the reasons of this contradiction have been investigated. It is concluded that the Csp2-Csp2 bond length in acrolein is determined by influence of the bonding for it π-π conjugation and antibonding n → σ∗ hyperconjugation between the oxygen lone pair and the antibonding orbital of the single bond. It was shown also this bond length depends on the difference in energy of conjugative and hyperconjugative interactions.

  10. Preparation and immunological properties of procaine-protein conjugates

    International Nuclear Information System (INIS)

    Liakopoulou, A.

    1981-01-01

    Procaine was conjugated to BSA and rat and rabbit Gf using the carbodiimide method and 14 C-procaine as tracer. The composition of the conjugates could be varied depending on the time of incubation and the concentration of procaine in the reaction mixtures. Procaine-BSA conjugates were soluble in water or saline. However, procaine conjugates to rat or rabbit Gf were not readily soluble in saline. These conjugates were good for immunization purposes, but it was cumbersome to work with them when clear solutions were needed, as in the immunochemical procedures used in this study. The immunological properties of the conjugates were studied in rats and rabbits. Rats responded with production of IgGa and precipitating antibodies to the procaine group, but IgE antibodies to the immunogen could not be detected. Furthermore, precipitating antibodies towards the procaine group were raised in rabbits. When BSA was the protein carrier, antibodies to the carrier molecule were also detected in both rats and rabbits. The conjugates of procaine to rat or rabbit Gf did not elicit antibody response to the carrier molecule when used in the homologous species. Hapten inhibition studies suggested that, in the rabbit, antibodies were also produced with specificity directed towards the molecular configuration of the hapten-carrier bond. (author)

  11. Qualidade conjugal: mapeando conceitos

    Directory of Open Access Journals (Sweden)

    Clarisse Mosmann

    2006-12-01

    Full Text Available 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 na definição da qualidade conjugal: recursos pessoais dos cônjuges, contexto de inserção do casal e processos adaptativos. Neste sentido, a qualidade conjugal é resultado do processo dinâmico e interativo do casal, razão deste caráter multidimensional.

  12. Conjugate Gaze Palsies

    Science.gov (United States)

    ... version Home Brain, Spinal Cord, and Nerve Disorders Cranial Nerve Disorders Conjugate Gaze Palsies Horizontal gaze palsy Vertical ... Version. DOCTORS: Click here for the Professional Version Cranial Nerve Disorders Overview of the Cranial Nerves Internuclear Ophthalmoplegia ...

  13. Conjugated Polymer Solar Cells

    National Research Council Canada - National Science Library

    Paraschuk, Dmitry Y

    2006-01-01

    This report results from a contract tasking Moscow State University as follows: Conjugated polymers are promising materials for many photonics applications, in particular, for photovoltaic and solar cell devices...

  14. 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.

  15. Factors Governing Intercalation of Fullerenes and Other Small Molecules Between the Side Chains of Semiconducting Polymers Used in Solar Cells

    KAUST Repository

    Miller, Nichole Cates; Cho, Eunkyung; Gysel, Roman; Risko, Chad; Coropceanu, Veaceslav; Miller, Chad E.; Sweetnam, Sean; Sellinger, Alan; Heeney, Martin; McCulloch, Iain; Bré das, Jean-Luc; Toney, Michael F.; McGehee, Michael D.

    2012-01-01

    bimolecular crystals did not form in the other studied polymer:nonfullerene blends, including those with both conjugated and non-conjugated small molecules. DSC and molecular simulations demonstrate that strong polymer-fullerene interactions can exist

  16. Molecule nanoweaver

    Science.gov (United States)

    Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

    2009-03-10

    A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

  17. Evidence for quantum interference in sams of arylethynylene thiolates in tunneling junctions with eutectic Ga-In (EGaIn) top-contacts : The influence of π-conjugation on the single-molecule conductance at a solid/liquid interface

    NARCIS (Netherlands)

    Fracasso, Davide; Valkenier, Hennie; Hummelen, Jan C.; Solomon, Gemma C.; Chiechi, Ryan C.; Hong, Wenjing; Mészáros, Gábor; Zsolt Manrique, David; Mishchenko, Artem; Putz, Alexander; Moreno García, Pavel; Lambert, Colin J.; Wandlowski, Thomas; Ruitenbeek, J.M. van

    2011-01-01

    This paper compares the current density (J) versus applied bias (V) of self-assembled monolayers (SAMs) of three different ethynylthiophenol-functionalized anthracene derivatives of approximately the same thickness with linear-conjugation (AC), cross-conjugation (AQ), and broken-conjugation (AH)

  18. Understanding the atmospheric pressure ionization of petroleum components: The effects of size, structure, and presence of heteroatoms

    International Nuclear Information System (INIS)

    Huba, Anna Katarina; Huba, Kristina; Gardinali, Piero R.

    2016-01-01

    Understanding the composition of crude oil and its changes with weathering is essential when assessing its provenience, fate, and toxicity. High-resolution mass spectrometry (HRMS) has provided the opportunity to address the complexity of crude oil by assigning molecular formulae, and sorting compounds into “classes” based on heteroatom content. However, factors such as suppression effects and discrimination towards certain components severely limit a truly comprehensive mass spectrometric characterization, and, despite the availability of increasingly better mass spectrometers, a complete characterization of oil still represents a major challenge. In order to fully comprehend the significance of class abundances, as well as the nature and identity of compounds detected, a good understanding of the ionization efficiency of the various compound classes is indispensable. The current study, therefore, analyzed model compounds typically found in crude oils by high-resolution mass spectrometry with atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI), and electrospray ionization (ESI), in order to provide a better understanding of benefits and drawbacks of each source. The findings indicate that, overall, APPI provides the best results, being able to ionize the broadest range of compounds, providing the best results with respect to ionization efficiencies, and exhibiting the least suppression effects. However, just like in the other two sources, in APPI several factors have shown to affect the ionization efficiency of petroleum model compounds. The main such factor is the presence or absence of functional groups that can be easily protonated/deprotonated, in addition to other factors such as size, methylation level, presence of heteroatoms, and ring structure. Overall, this study evidences the intrinsic limitations and benefits of each of the three sources, and should provide the fundamental knowledge required to expand the

  19. Understanding the atmospheric pressure ionization of petroleum components: The effects of size, structure, and presence of heteroatoms

    Energy Technology Data Exchange (ETDEWEB)

    Huba, Anna Katarina; Huba, Kristina [Department of Chemistry & Biochemistry, Florida International University, 3000 NE 151 Street, Biscayne Bay Campus, North Miami, Florida 33181 (United States); Gardinali, Piero R. [Department of Chemistry & Biochemistry, Florida International University, 3000 NE 151 Street, Biscayne Bay Campus, North Miami, Florida 33181 (United States); Southeast Environmental Research Center (SERC), Florida International University, 3000 NE 151 Street, Biscayne Bay Campus, North Miami, Florida 33181 (United States)

    2016-10-15

    Understanding the composition of crude oil and its changes with weathering is essential when assessing its provenience, fate, and toxicity. High-resolution mass spectrometry (HRMS) has provided the opportunity to address the complexity of crude oil by assigning molecular formulae, and sorting compounds into “classes” based on heteroatom content. However, factors such as suppression effects and discrimination towards certain components severely limit a truly comprehensive mass spectrometric characterization, and, despite the availability of increasingly better mass spectrometers, a complete characterization of oil still represents a major challenge. In order to fully comprehend the significance of class abundances, as well as the nature and identity of compounds detected, a good understanding of the ionization efficiency of the various compound classes is indispensable. The current study, therefore, analyzed model compounds typically found in crude oils by high-resolution mass spectrometry with atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI), and electrospray ionization (ESI), in order to provide a better understanding of benefits and drawbacks of each source. The findings indicate that, overall, APPI provides the best results, being able to ionize the broadest range of compounds, providing the best results with respect to ionization efficiencies, and exhibiting the least suppression effects. However, just like in the other two sources, in APPI several factors have shown to affect the ionization efficiency of petroleum model compounds. The main such factor is the presence or absence of functional groups that can be easily protonated/deprotonated, in addition to other factors such as size, methylation level, presence of heteroatoms, and ring structure. Overall, this study evidences the intrinsic limitations and benefits of each of the three sources, and should provide the fundamental knowledge required to expand the

  20. In Vitro Evaluation of Third Generation PAMAM Dendrimer Conjugates

    Directory of Open Access Journals (Sweden)

    Mohammad Najlah

    2017-10-01

    Full Text Available The present study compares the use of high generation G3 and low generation G0 Polyamidoamine (PAMAM dendrimers as drug carriers of naproxen (NAP, a poorly water soluble drug. Naproxen was conjugated to G3 in different ratios and to G0 in a 1:1 ratio via a diethylene glycol linker. A lauroyl chain (L, a lipophilic permeability enhancer, was attached to G3 and G0 prodrugs. The G3 and G0 conjugates were more hydrophilic than naproxen as evaluated by the measurement of partitioning between 1-octanol and a phosphate buffer at pH 7.4 and pH 1.2. The unmodified surface PAMAM-NAP conjugates showed significant solubility enhancements of NAP at pH 1.2; however, with the number of NAP conjugated to G3, this was limited to 10 molecules. The lactate dehydrogenase (LDH assay indicated that the G3 dendrimer conjugates had a concentration dependent toxicity towards Caco-2 cells. Attaching naproxen to the surface of the dendrimer increased the IC50 of the resulting prodrugs towards Caco-2 cells. The lauroyl G3 conjugates showed the highest toxicity amongst the PAMAM dendrimer conjugates investigated and were significantly more toxic than the lauroyl-G0-naproxen conjugates. The permeability of naproxen across monolayers of Caco-2 cells was significantly increased by its conjugation to either G3 or G0 PAMAM dendrimers. Lauroyl-G0 conjugates displayed considerably lower cytotoxicity than G3 conjugates and may be preferable for use as a drug carrier for low soluble drugs such as naproxen.

  1. Highly Efficient Electrocatalysts for Oxygen Reduction Reaction Based on 1D Ternary Doped Porous Carbons Derived from Carbon Nanotube Directed Conjugated Microporous Polymers

    KAUST Repository

    He, Yafei; Gehrig, Dominik; Zhang, Fan; Lu, Chenbao; Zhang, Chao; Cai, Ming; Wang, Yuanyuan; Laquai, Fré dé ric; Zhuang, Xiaodong; Feng, Xinliang

    2016-01-01

    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.One-dimensional (1D) porous materials have shown great potential for gas storage and separation, sensing, energy storage, and conversion. However, the controlled approach for preparation of 1D porous materials, especially porous organic materials, still remains a great challenge due to the poor dispersibility and solution processability of the porous materials. Here, carbon nanotube (CNT) templated 1D conjugated microporous polymers (CMPs) are prepared using a layer-by-layer method. As-prepared CMPs possess high specific surface areas of up to 623 m2 g-1 and exhibit strong electronic interactions between p-type CMPs and n-type CNTs. The CMPs are used as precursors to produce heteroatom-doped 1D porous carbons through direct pyrolysis. As-produced ternary heteroatom-doped (B/N/S) 1D porous carbons possess high specific surface areas of up to 750 m2 g-1, hierarchical porous structures, and excellent electrochemical-catalytic performance for oxygen reduction reaction. Both of the diffusion-limited current density (4.4 mA cm-2) and electron transfer number (n = 3.8) for three-layered 1D porous carbons are superior to those for random 1D porous carbon. These results demonstrate that layered and core-shell type 1D CMPs and related heteroatom-doped 1D porous carbons can be rationally designed and controlled prepared for high performance energy-related applications.

  2. Highly Efficient Electrocatalysts for Oxygen Reduction Reaction Based on 1D Ternary Doped Porous Carbons Derived from Carbon Nanotube Directed Conjugated Microporous Polymers

    KAUST Repository

    He, Yafei

    2016-10-11

    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.One-dimensional (1D) porous materials have shown great potential for gas storage and separation, sensing, energy storage, and conversion. However, the controlled approach for preparation of 1D porous materials, especially porous organic materials, still remains a great challenge due to the poor dispersibility and solution processability of the porous materials. Here, carbon nanotube (CNT) templated 1D conjugated microporous polymers (CMPs) are prepared using a layer-by-layer method. As-prepared CMPs possess high specific surface areas of up to 623 m2 g-1 and exhibit strong electronic interactions between p-type CMPs and n-type CNTs. The CMPs are used as precursors to produce heteroatom-doped 1D porous carbons through direct pyrolysis. As-produced ternary heteroatom-doped (B/N/S) 1D porous carbons possess high specific surface areas of up to 750 m2 g-1, hierarchical porous structures, and excellent electrochemical-catalytic performance for oxygen reduction reaction. Both of the diffusion-limited current density (4.4 mA cm-2) and electron transfer number (n = 3.8) for three-layered 1D porous carbons are superior to those for random 1D porous carbon. These results demonstrate that layered and core-shell type 1D CMPs and related heteroatom-doped 1D porous carbons can be rationally designed and controlled prepared for high performance energy-related applications.

  3. Formation of mixed aryl-, alkyl-lithium aggregates in the heteroatom assisted lithiation of a,a'-dialkyl substituted 1,3-bis[(dimethylamino)methyl]benzene

    NARCIS (Netherlands)

    Koten, G. van; Donkervoort, J.G.; Vicario, J.L.; Rijnberg, E.; Jastrzebski, J.T.B.H.; Kooijman, H.; Spek, A.L.

    1998-01-01

    The heteroatom assisted lithiation of 1, 3-bis[1-(dimethylamino)ethyl]benzene with n-BuLi afforded 2,6-bis[1-(dimethylamino)ethyl]phenyllithium. An X-ray crystal structure determination revealed a dimeric aggregate in which the four benzylic chiral centers are identical, pointing to stereoselective

  4. Catalytic hydrotreatment of Illinois No. 6 coal-derived naphtha: comparison of molybdenum nitride and molybdenum sulfide for heteroatom removal

    Energy Technology Data Exchange (ETDEWEB)

    Raje, A.; Liaw, S.J.; Chary, K.V.R.; Davis, B.H. [University of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    1995-03-16

    The hydrotreatment of naphtha derived from Illinois No. 6 coal was investigated using molybdenum sulfide and nitride catalysts. The two catalysts are compared on the basis of total catalyst weight. Molybdenum sulfide is more active than molybdenum nitride for hydrodesulfurization (HDS) of a coal-derived naphtha. The rate of hydrodeoxygenation (HDO) of the naphtha over both catalysts are comparable. For hydrodenitrogenation (HDN), the sulfide is more active than the nitride only at higher temperatures ({gt}325{degree}C). Based upon conversion data, the naphtha can be lumped into a reactive and a less reactive fraction with each following first-order kinetics for heteroatom removal. The HDS and HDN rates and activation energies of the less reactive lump are smaller for the nitride than for the sulfide catalyst.

  5. Selective Semihydrogenation of Alkynes Catalyzed by Pd Nanoparticles Immobilized on Heteroatom-Doped Hierarchical Porous Carbon Derived from Bamboo Shoots.

    Science.gov (United States)

    Ji, Guijie; Duan, Yanan; Zhang, Shaochun; Fei, Benhua; Chen, Xiufang; Yang, Yong

    2017-09-11

    Highly dispersed palladium nanoparticles (Pd NPs) immobilized on heteroatom-doped hierarchical porous carbon supports (N,O-carbon) with large specific surface areas are synthesized by a wet chemical reduction method. The N,O-carbon derived from naturally abundant bamboo shoots is fabricated by a tandem hydrothermal-carbonization process without assistance of any templates, chemical activation reagents, or exogenous N or O sources in a simple and ecofriendly manner. The prepared Pd/N,O-carbon catalyst shows extremely high activity and excellent chemoselectivity for semihydrogenation of a broad range of alkynes to versatile and valuable alkenes under ambient conditions. The catalyst can be readily recovered for successive reuse with negligible loss in activity and selectivity, and is also applicable for practical gram-scale reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Effects of Acids, Bases, and Heteroatoms on Proximal Radial Distribution Functions for Proteins.

    Science.gov (United States)

    Nguyen, Bao Linh; Pettitt, B Montgomery

    2015-04-14

    The proximal distribution of water around proteins is a convenient method of quantifying solvation. We consider the effect of charged and sulfur-containing amino acid side-chain atoms on the proximal radial distribution function (pRDF) of water molecules around proteins using side-chain analogs. The pRDF represents the relative probability of finding any solvent molecule at a distance from the closest or surface perpendicular protein atom. We consider the near-neighbor distribution. Previously, pRDFs were shown to be universal descriptors of the water molecules around C, N, and O atom types across hundreds of globular proteins. Using averaged pRDFs, a solvent density around any globular protein can be reconstructed with controllable relative error. Solvent reconstruction using the additional information from charged amino acid side-chain atom types from both small models and protein averages reveals the effects of surface charge distribution on solvent density and improves the reconstruction errors relative to simulation. Solvent density reconstructions from the small-molecule models are as effective and less computationally demanding than reconstructions from full macromolecular models in reproducing preferred hydration sites and solvent density fluctuations.

  7. 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.

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

    Science.gov (United States)

    Stavis, Samuel M [Ithaca, NY; Edel, Joshua B [Brookline, MA; Samiee, Kevan T [Ithaca, NY; Craighead, Harold G [Ithaca, NY

    2008-07-29

    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.

  9. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

  10. Synthesis of Mikto-Arm Star Peptide Conjugates.

    Science.gov (United States)

    Koo, Jin Mo; Su, Hao; Lin, Yi-An; Cui, Honggang

    2018-01-01

    Mikto-arm star peptide conjugates are an emerging class of self-assembling peptide-based structural units that contain three or more auxiliary segments of different chemical compositions and/or functionalities. This group of molecules exhibit interesting self-assembly behavior in solution due to their chemically asymmetric topology. Here we describe the detailed procedure for synthesis of an ABC Mikto-arm star peptide conjugate in which two immiscible entities (a saturated hydrocarbon and a hydrophobic and lipophobic fluorocarbon) are conjugated onto a short β-sheet forming peptide sequence, GNNQQNY, derived from the Sup35 prion, through a lysine junction. Automated and manual Fmoc-solid phase synthesis techniques are used to synthesize the Mikto-arm star peptide conjugates, followed by HPLC purification. We envision that this set of protocols can afford a versatile platform to synthesize a new class of peptidic building units for diverse applications.

  11. Interpretation of observations of subauroral red arches in conjugate regions at the OVI-10 satellite

    International Nuclear Information System (INIS)

    Pavlov, A.V.

    1996-01-01

    Calculations of the velocities of SAR-arches in the north and south hemispheres in the conjugate regions with regard to non-Boltzman distribution of nitrogen molecules along the oscillation levels were carried out

  12. IRDye78 Conjugates for Near-Infrared Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Atif Zaheer

    2002-10-01

    Full Text Available The detection of human malignancies by near-infrared (NIR fluorescence will require the conjugation of cancer-specific ligands to NIR fluorophores that have optimal photoproperties and pharmacokinetics. IRDye78, a tetra-sulfonated heptamethine indocyanine NIR fluorophore, meets most of the criteria for an in vivo imaging agent, and is available as an N-hydroxysuccinimide ester for conjugation to low-molecular-weight ligands. However, IRDye78 has a high charge-to-mass ratio, complicating purification of conjugates. It also has a potentially labile linkage between fluorophore and ligand. We have developed an ion-pairing purification strategy for IRDye78 that can be performed with a standard C18 column under neutral conditions, thus preserving the stability of fluorophore, ligand, and conjugate. By employing parallel evaporative light scatter and absorbance detectors, all reactants and products are identified, and conjugate purity is maximized. We describe reversible and irreversible conversions of IRDye78 that can occur during sample purification, and describe methods for preserving conjugate stability. Using seven ligands, spanning several classes of small molecules and peptides (neutral, charged, and/or hydrophobic, we illustrate the robustness of these methods, and confirm that IRDye78 conjugates so purified retain bioactivity and permit NIR fluorescence imaging of specific targets.

  13. 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....

  14. Photoluminescence in conjugated polymers

    International Nuclear Information System (INIS)

    Furst, J.E.; Laugesen, R.; Dastoor, P.; McNeill, C.

    2002-01-01

    Full text: Conjugated polymers combine the electronic and optical properties of semiconductors with the processability of polymers. They contain a sequence of alternate single and double carbon bonds so that the overlap of unhybridised p z orbitals creates a delocalised ρ system which gives semiconducting properties with p-bonding (valence) and p* -antibonding (conduction) bands. Photoluminesence (PL) in conjugated polymers results from the radiative decay of singlet excitons confined to a single chain. The present work is the first in a series of studies in our laboratory that will characterize the optical properties of conjugated polymers. The experiment involves the illumination of thin films of conjugated polymer with UV light (I=360 nm) and observing the subsequent fluorescence using a custom-built, fluorescence spectrometer. Photoluminesence spectra provide basic information about the structure of the polymer film. A typical spectrum is shown in the accompanying figure. The position of the first peak is related to the polymer chain length and resolved multiple vibronic peaks are an indication of film structure and morphology. We will also present results related to the optical degradation of these materials when exposed to air and UV light

  15. DNA-cell conjugates

    Science.gov (United States)

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

    2018-05-15

    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.

  16. DNA-cell conjugates

    Science.gov (United States)

    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.

  17. Conjugated material self-assembly : towards supramolecular electronics

    NARCIS (Netherlands)

    Leclère, P.E.L.G.; Surin, M.; Cavallini, M.; Jonkheijm, P.; Henze, O.; Schenning, A.P.H.J.; Biscarini, F.; Grimsdale, A.C.; Feast, W.J.; Meijer, E.W.; Müllen, K.; Brédas, J.L.; Lazzaroni, R.

    2004-01-01

    Properties of organic electronic materials in solid-state are determined as individual molecules and molecular assembly. It is essential to optimize conjugated materials to control performance of molecular assembly that constitute electronic devices such as light-emitting diodes and solar cells, and

  18. Atkins' molecules

    CERN Document Server

    Atkins, Peters

    2003-01-01

    Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

  19. Interstellar Molecules

    Science.gov (United States)

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  20. Bimetallic promotion of cooperative hydrogen transfer and heteroatom removal in coal liquefaction. Final technical report, September 1, 1988--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Eisch, J.J.

    1992-04-07

    The ultimate objective of this research has been to uncover novel reagents and experimental conditions for heteroatom removal and hydrogen transfer processes, which would be applicable to the liquefaction of coal under low-severity conditions. To this end, one phase of this research has investigated the cleavage of carbon-heteroatom bonds involving sulfur, oxygen, nitrogen and halogen by subvalent transition-metal complexes. A second phase of the study has assessed the capability of the same transition-metal complexes or of organoaluminum Lewis acids to catalyze the cleavage of carbon-hydrogen bonds in aromatics and hence to promote hydrogen shuttling. Finally, a third phase of our work has uncovered a remarkable synergistic effect of combinations of transition metals with organoaluminum Lewis acids on hydrogen shuttling between aromatics and hydroaromatics. (VC)

  1. Alkyl halide-free heteroatom alkylation and epoxidation facilitated by a recyclable polymer-supported oxidant for the in-flow preparation of diazo compounds.

    Science.gov (United States)

    Nicolle, Simon M; Hayes, Christopher J; Moody, Christopher J

    2015-03-16

    Highly reactive metal carbenes, generated from simple ketones via diazo compounds, including diazo-amides and -phosphonates, using a recyclable reagent in-flow, are transient but versatile electrophiles for heteroatom alkylation reactions and for epoxide formation. The method produces no organic waste, with the only by-products being water, KI and nitrogen, without the attendant hazards of isolation of intermediate diazo compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Layer-by-layer assembled heteroatom-doped graphene films with ultrahigh volumetric capacitance and rate capability for micro-supercapacitors.

    Science.gov (United States)

    Wu, Zhong-Shuai; Parvez, Khaled; Winter, Andreas; Vieker, Henning; Liu, Xianjie; Han, Sheng; Turchanin, Andrey; Feng, Xinliang; Müllen, Klaus

    2014-07-09

    Highly uniform, ultrathin, layer-by-layer heteroatom (N, B) co-doped graphene films are fabricated for high-performance on-chip planar micro-supercapacitors with an ultrahigh volumetric capacitance of ∼488 F cm(-3) and excellent rate capability due to the synergistic effect of nitrogen and boron co-doping. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis of Novel Synthetic Vitamin K Analogues Prepared by Introduction of a Heteroatom and a Phenyl Group That Induce Highly Selective Neuronal Differentiation of Neuronal Progenitor Cells.

    Science.gov (United States)

    Kimura, Kimito; Hirota, Yoshihisa; Kuwahara, Shigefumi; Takeuchi, Atsuko; Tode, Chisato; Wada, Akimori; Osakabe, Naomi; Suhara, Yoshitomo

    2017-03-23

    We synthesized novel vitamin K 2 analogues that incorporated a heteroatom and an aromatic ring in the side chain and evaluated their effect on the selective differentiation of neuronal progenitor cells into neurons in vitro. The results showed that a menaquinone-2 analogue bearing a p-fluoroaniline had the most potent activity, which was more than twice as great as the control. In addition, the neuronal selectivity was more than 3 times greater than the control.

  4. Tunable and selective hydrogenation of furfural to furfuryl alcohol and cyclopentanone over Pt supported on biomass-derived porous heteroatom doped carbon.

    Science.gov (United States)

    Liu, Xiuyun; Zhang, Bo; Fei, Benhua; Chen, Xiufang; Zhang, Junyi; Mu, Xindong

    2017-09-21

    The search for and exploitation of efficient catalytic systems for selective conversion of furfural into various high value-added chemicals remains a huge challenge for green synthesis in the chemical industry. Here, novel Pt nanoparticles supported on bamboo shoot-derived porous heteroatom doped carbon materials were designed as highly active catalysts for controlled hydrogenation of furfural in aqueous media. The porous heteroatom doped carbon supported Pt catalysts were endowed with a large surface area with a hierarchical porous structure, a high content of nitrogen and oxygen functionalities, a high dispersion of the Pt nanoparticles, good water dispersibility and reaction stability. Benefiting from these features, the novel Pt catalysts displayed a high activity and controlled tunable selectivity for furfural hydrogenation to produce furfuryl alcohol and cyclopentanone in water. The product selectivity could be easily modulated by controlling the carbonization temperature of the porous heteroatom doped carbon support and the reaction conditions (temperature and H 2 pressure). Under mild conditions (100 °C, 1 MPa H 2 ), furfuryl alcohol was obtained in water with complete conversion of the furfural and an impressive furfuryl alcohol selectivity of >99% in the presence of Pt/NC-BS-500. A higher reaction temperature, in water, favored rearrangement of the furfural (FFA) with Pt/NC-BS-800 as the catalyst, which resulted in a high cyclopentanone yield of >76% at 150 °C and 3 MPa H 2 . The surface properties and pore structure of the heteroatom doped carbon support, adjusted using the carbonization temperature, might determine the interactions between the Pt nanoparticles, carbon support and catalytic reactants in water, which in turn could have led to a good selectivity control. The effect of different reaction temperatures and reaction times on the product selectivity was also explored. Combined with exploration of the distribution of the reaction products, a

  5. Molecularly precise dendrimer-drug conjugates with tunable drug release for cancer therapy.

    Science.gov (United States)

    Zhou, Zhuxian; Ma, Xinpeng; Murphy, Caitlin J; Jin, Erlei; Sun, Qihang; Shen, Youqing; Van Kirk, Edward A; Murdoch, William J

    2014-10-06

    The structural preciseness of dendrimers makes them perfect drug delivery carriers, particularly in the form of dendrimer-drug conjugates. Current dendrimer-drug conjugates are synthesized by anchoring drug and functional moieties onto the dendrimer peripheral surface. However, functional groups exhibiting the same reactivity make it impossible to precisely control the number and the position of the functional groups and drug molecules anchored to the dendrimer surface. This structural heterogeneity causes variable pharmacokinetics, preventing such conjugates to be translational. Furthermore, the highly hydrophobic drug molecules anchored on the dendrimer periphery can interact with blood components and alter the pharmacokinetic behavior. To address these problems, we herein report molecularly precise dendrimer-drug conjugates with drug moieties buried inside the dendrimers. Surprisingly, the drug release rates of these conjugates were tailorable by the dendrimer generation, surface chemistry, and acidity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Tetra-heteroatom self-doped carbon nanosheets derived from silkworm excrement for high-performance supercapacitors

    Science.gov (United States)

    Lei, Shuijin; Chen, Lianfu; Zhou, Wei; Deng, Peiqin; Liu, Yan; Fei, Linfeng; Lu, Wei; Xiao, Yanhe; Cheng, Baochang

    2018-03-01

    Carbon materials are deemed to be competitive candidate electrode materials for energy storage systems. It is still a great challenge to explore advanced carbon-based electrode materials for high-performance supercapacitors by a facile, economical and efficient method. In this work, N-, P-, S-, O-self-doped carbon nanosheets with high surface area and well-developed porosity are successfully prepared by pyrolysis carbonization and post KOH activation from silkworm excrement, a novel abundant, low-cost and eco-friendly agricultural waste. Thanks to their unique multi-heteroatom doping and porous structure, the obtained carbon materials exhibit high charge storage capacity with a specific capacitance of 401 F g-1 at a current density of 0.5 A g-1 in 6 M KOH and good cycling stability with a capacitance retention of 93.8% over 10000 cycles. A symmetric supercapacitor device using 1 M Na2SO4 aqueous solution as the electrolyte can deliver a specific capacitance of 41.7 F g-1 at a current density of 0.5 A g-1, and a high energy density of 23.17 Wh kg-1 at a power density of 500 W kg-1 with a wide voltage window of 2.0 V. This work develops a new strategy to produce favorable carbon-based electrode materials for supercapacitors with high electrochemical performances.

  7. Dual peptide conjugation strategy for improved cellular uptake and mitochondria targeting.

    Science.gov (United States)

    Lin, Ran; Zhang, Pengcheng; Cheetham, Andrew G; Walston, Jeremy; Abadir, Peter; Cui, Honggang

    2015-01-21

    Mitochondria are critical regulators of cellular function and survival. Delivery of therapeutic and diagnostic agents into mitochondria is a challenging task in modern pharmacology because the molecule to be delivered needs to first overcome the cell membrane barrier and then be able to actively target the intracellular organelle. Current strategy of conjugating either a cell penetrating peptide (CPP) or a subcellular targeting sequence to the molecule of interest only has limited success. We report here a dual peptide conjugation strategy to achieve effective delivery of a non-membrane-penetrating dye 5-carboxyfluorescein (5-FAM) into mitochondria through the incorporation of both a mitochondrial targeting sequence (MTS) and a CPP into one conjugated molecule. Notably, circular dichroism studies reveal that the combined use of α-helix and PPII-like secondary structures has an unexpected, synergistic contribution to the internalization of the conjugate. Our results suggest that although the use of positively charged MTS peptide allows for improved targeting of mitochondria, with MTS alone it showed poor cellular uptake. With further covalent linkage of the MTS-5-FAM conjugate to a CPP sequence (R8), the dually conjugated molecule was found to show both improved cellular uptake and effective mitochondria targeting. We believe these results offer important insight into the rational design of peptide conjugates for intracellular delivery.

  8. Pulse gas chromatographic study of adsorption of substituted aromatics and heterocyclic molecules on MIL-47 at zero coverage.

    Science.gov (United States)

    Duerinck, Tim; Couck, Sarah; Vermoortele, Frederik; De Vos, Dirk E; Baron, Gino V; Denayer, Joeri F M

    2012-10-02

    The low coverage adsorptive properties of the MIL-47 metal organic framework toward aromatic and heterocyclic molecules are reported in this paper. The effect of molecular functionality and size on Henry adsorption constants and adsorption enthalpies of alkyl and heteroatom functionalized benzene derivates and heterocyclic molecules was studied using pulse gas chromatography. By means of statistical analysis, experimental data was analyzed and modeled using principal component analysis and partial least-squares regression. Structure-property relationships were established, revealing and confirming several trends. Among the molecular properties governing the adsorption process, vapor pressure, mean polarizability, and dipole moment play a determining role.

  9. Expeditious synthesis of coumarin-pyridone conjugates molecules ...

    Indian Academy of Sciences (India)

    RAJNI KHAJURIA

    2017-09-06

    Sep 6, 2017 ... Compound 2k showed good inhibitory potential against the tested yeasts organisms. ... HO. O. Me. OH. Pavietin. Anti-fungal. N. O. ABT 719. Anti-bacterial. F. Me. N ...... 2-one1a-ounderwent NH4OAc catalyzed Michael addi-.

  10. Magnetic Field Effect in Conjugated Molecules-Based Devices

    Science.gov (United States)

    2017-10-23

    line shapes of magnetoconductance curves for diodes of pentacene:fullerene charge transfer complexes” Org . Electron. 15, 3076 (2014). (AOARD-14-4012...2. “The origins in the transformation of ambipolar to n-type pentacene-based organic field-effect transistors” Org . Electron. 15, 1759 (2014...shell nanoparticles doped PEDOT:PSS hole-transporter. Org . Electron. : Phys. Mater. Appl. 33, 221-226 (2016). 5. Huang, X., Wang, K. Yi, C., Meng, T

  11. Adhesion molecules

    CERN Document Server

    Preedy, Victor R

    2016-01-01

    This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

  12. 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.

  13. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule Matters - Dinitrogen. A G Samuelson J Jabadurai. Volume 16 Issue 12 ... Author Affiliations. A G Samuelson1 J Jabadurai1. Department of Inroganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

  14. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 9. Molecule Matters - A Chromium Compound with a Quintuple Bond. K C Kumara Swamy. Feature Article Volume 11 Issue 9 September 2006 pp 72-75. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. Are conjugated linolenic acid isomers an alternative to conjugated linoleic acid isomers in obesity prevention?

    Science.gov (United States)

    Miranda, Jonatan; Arias, Noemi; Fernández-Quintela, Alfredo; del Puy Portillo, María

    2014-04-01

    Despite its benefits, conjugated linoleic acid (CLA) may cause side effects after long-term administration. Because of this and the controversial efficacy of CLA in humans, alternative biomolecules that may be used as functional ingredients have been studied in recent years. Thus, conjugated linolenic acid (CLNA) has been reported to be a potential anti-obesity molecule which may have additional positive effects related to obesity. According to the results reported in obesity, CLNA needs to be given at higher doses than CLA to be effective. However, because of the few studies conducted so far, it is still difficult to reach clear conclusions about the potential use of these CLNAs in obesity and its related changes (insulin resistance, dyslipidemia, or inflammation). Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  16. Heteroatom Polymer-Derived 3D High-Surface-Area and Mesoporous Graphene Sheet-Like Carbon for Supercapacitors.

    Science.gov (United States)

    Sheng, Haiyang; Wei, Min; D'Aloia, Alyssa; Wu, Gang

    2016-11-09

    Current supercapacitors suffer from low energy density mainly due to the high degree of microporosity and insufficient hydrophilicity of their carbon electrodes. Development of a supercapacitor capable of simultaneously storing as much energy as a battery, along with providing sufficient power and long cycle stability would be valued for energy storage applications and innovations. Differing from commonly studied reduced graphene oxides, in this work we identified an inexpensive heteroatom polymer (polyaniline-PANI) as a carbon/nitrogen precursor, and applied a controlled thermal treatment at elevated temperature to convert PANI into 3D high-surface-area graphene-sheet-like carbon materials. During the carbonization process, various transition metals including Fe, Co, and Ni were added, which play critical roles in both catalyzing the graphitization and serving as pore forming agents. Factors including post-treatments, heating temperatures, and types of metal were found crucial for achieving enhanced capacitance performance on resulting carbon materials. Using FeCl 3 as precursor along with optimal heating temperature 1000 °C and mixed acid treatment (HCl+HNO 3 ), the highest Brunauer-Emmett-Teller (BET) surface area of 1645 m 2 g -1 was achieved on the mesopore dominant graphene-sheet-like carbon materials. The unique morphologies featured with high-surface areas, dominant mesopores, proper nitrogen doping, and 3D graphene-like structures correspond to remarkably enhanced electrochemical specific capacitance up to 478 Fg -1 in 1.0 M KOH at a scan rate of 5 mV s -1 . Furthermore, in a real two-electrode system of a symmetric supercapacitor, a specific capacitance of 235 Fg -1 using Nafion binder is obtained under a current density of 1 Ag -1 by galvanostatic charge-discharge tests in 6.0 M KOH. Long-term cycle stability up to 5000 cycles by using PVDF binder in electrode was systematically evaluated as a function of types of metals and current densities.

  17. Effective Approach for Increasing the Heteroatom Doping Levels of Porous Carbons for Superior CO2 Capture and Separation Performance.

    Science.gov (United States)

    Abdelmoaty, Yomna H; Tessema, Tsemre-Dingel; Norouzi, Nazgol; El-Kadri, Oussama M; Turner, Joseph B McGee; El-Kaderi, Hani M

    2017-10-18

    Development of efficient sorbents for carbon dioxide (CO 2 ) capture from flue gas or its removal from natural gas and landfill gas is very important for environmental protection. A new series of heteroatom-doped porous carbon was synthesized directly from pyrazole/KOH by thermolysis. The resulting pyrazole-derived carbons (PYDCs) are highly doped with nitrogen (14.9-15.5 wt %) as a result of the high nitrogen-to-carbon ratio in pyrazole (43 wt %) and also have a high oxygen content (16.4-18.4 wt %). PYDCs have a high surface area (SA BET = 1266-2013 m 2 g -1 ), high CO 2 Q st (33.2-37.1 kJ mol -1 ), and a combination of mesoporous and microporous pores. PYDCs exhibit significantly high CO 2 uptakes that reach 2.15 and 6.06 mmol g -1 at 0.15 and 1 bar, respectively, at 298 K. At 273 K, the CO 2 uptake improves to 3.7 and 8.59 mmol g -1 at 0.15 and 1 bar, respectively. The reported porous carbons also show significantly high adsorption selectivity for CO 2 /N 2 (128) and CO 2 /CH 4 (13.4) according to ideal adsorbed solution theory calculations at 298 K. Gas breakthrough studies of CO 2 /N 2 (10:90) at 298 K showed that PYDCs display excellent separation properties. The ability to tailor the physical properties of PYDCs as well as their chemical composition provides an effective strategy for designing efficient CO 2 sorbents.

  18. Click chemistry based biomolecular conjugation monitoring using surface-enhanced Raman spectroscopy mapping

    DEFF Research Database (Denmark)

    Palla, Mirko; Kumar, Shiv; Li, Zengmin

    2016-01-01

    We describe here a novel surface-enhanced Raman spectroscopy (SERS) based technique for monitoring the conjugation of small molecules by the well-known click reaction between an alkyne and azido moiety on the partner molecules. The monitoring principle is based on the loss of the characteristic...... alkyne/azide Raman signal with triazole formation in the reaction as a function of time. Since these universal Raman reporter groups are specific for click reactions, this method may facilitate a broad range of applications for monitoring the conjugation efficiency of molecules in diverse areas...

  19. Principles of conjugating quantum dots to proteins via carbodiimide chemistry

    International Nuclear Information System (INIS)

    Song Fayi; Chan, Warren C W

    2011-01-01

    The covalent coupling of nanomaterials to bio-recognition molecules is a critical intermediate step in using nanomaterials for biology and medicine. Here we investigate the carbodiimide-mediated conjugation of fluorescent quantum dots to different proteins (e.g., immunoglobulin G, bovine serum albumin, and horseradish peroxidase). To enable these studies, we developed a simple method to isolate quantum dot bioconjugates from unconjugated quantum dots. The results show that the reactant concentrations and protein type will impact the overall number of proteins conjugated onto the surfaces of the quantum dots, homogeneity of the protein–quantum dot conjugate population, quantum efficiency, binding avidity, and enzymatic kinetics. We propose general principles that should be followed for the successful coupling of proteins to quantum dots.

  20. 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...

  1. Self-doped carbon architectures with heteroatoms containing nitrogen, oxygen and sulfur as high-performance anodes for lithium- and sodium-ion batteries

    International Nuclear Information System (INIS)

    Lu, Mingjie; Yu, Wenhua; Shi, Jing; Liu, Wei; Chen, Shougang; Wang, Xin; Wang, Huanlei

    2017-01-01

    Highlights: •Self-doped carbon architectures with nitrogen, oxygen, and sulfur are derived from Carrageen. •The obtained carbon materials exhibit excellent electrochemical property. •The strategy provides a one-step synthesis route to design advanced anodes for batteries. -- Abstract: Nitrogen, oxygen and sulfur tridoped porous carbons have been successfully synthesized from natural biomass algae-Carrageen by using a simultaneous carbonization and activation procedure. The doped carbons with sponge-like interconnected architecture, partially ordered graphitic structure, and abundant heteroatom doping perform outstanding features for electrochemical energy storage. When tested as lithium-ion battery anodes, a high reversible capacity of 839 mAh g −1 can be obtained at the current density of 0.1 A g −1 after 100 cycles, while a high capacity of 228 mAh g −1 can be maintained at 10 A g −1 . Tested against sodium, a high specific capacity of 227 can be delivered at 0.1 A g −1 after 100 cycles, while a high capacity of 109 mAh g −1 can be achieved at 10 A g −1 . These results turn out that the doped carbons would be potential anode materials for lithium- and sodium-ion batteries, which can be achieved by a one-step and large-scale synthesis route. Our observation indicates that heteroatom doping (especially sulfur) can significantly promote ion storage and reduce irreversible ion trapping to some extent. This work gives a general route for designing carbon nanostructures with heteroatom doping for efficient energy storage.

  2. Conjugation in Escherichia coli

    Science.gov (United States)

    Boyer, Herbert

    1966-01-01

    Boyer, Herbert (Yale University, New Haven, Conn.). Conjugation in Escherichia coli. J. Bacteriol. 91:1767–1772. 1966.—The sex factor of Escherichia coli K-12 was introduced into an E. coli B/r strain by circumventing the host-controlled modification and restriction incompatibilities known to exist between these closely related strains. The sexual properties of the constructed F+ B strain and its Hfr derivatives were examined. These studies showed that the E. coli strain B/r F+ and Hfr derivatives are similar to the E. coli strain K-12 F+ and Hfr derivatives. However, the site of sex factor integration was found to be dependent on the host genome. PMID:5327905

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

    International Nuclear Information System (INIS)

    Hogenkamp, Harry P.C.; Collins, Douglas A.; Live, David; Benson, Linda M.; Naylor, Stephen

    2000-01-01

    Three vitamin B 12 (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 11 B 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 B 12 binding capacity assay. When compared with 57 Co 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 10 B cobalamin conjugates might be useful agents in treating malignant tumors via neutron capture therapy

  4. A nanodiamond-fluorescein conjugate for cell studies

    Science.gov (United States)

    Pedroso-Santana, Seidy; Fleitas-Salazar, Noralvis; Sarabia-Sainz, Andrei; Silva-Campa, Erika; Burgara-Estrella, Alexel; Angulo-Molina, Aracely; Melendrez, Rodrigo; Pedroza-Montero, Martin; Riera, Raul

    2018-03-01

    The use of nanodiamonds in studies with living systems generally involves the modification of their surfaces with functional groups. Fluorescent molecules can be attached to these groups, so that one can know the exact position of the particles in each moment of the interaction with the cells. Here we modify the surface of detonation nanodiamonds and nitrogen-vacancy center nanodiamonds using carboxylation and hydroxylation procedures. Subsequent reactions with silicates and cysteine, before addition of fluorescein allow to obtain fluorescent nano-conjugates. We used confocal microscopy to observe the position of nanodiamonds interacting with HeLa cells. At 3 h post-incubation the green fluorescence is localized in extracellular rounded like-vesicles assemblies while at 24 h the conjugates can be observed inside the cells. The measurement of the fluorescence emitted by both conjugates allowed to find an enhanced emission of fluorescein isothiocyanate (FITC) when the nitrogen-vacancy center is present. We propose the existence of a fluorescence enhancement by electron transference process. The procedure described in this work allows the functionalization of nanodiamonds with FITC and other molecules using functional surface groups and small size mediators. Also, as was proved in our work, the nanodiamond-fluorescein conjugates can be used to track nanoparticles position within the cell. Localization studies are particularly important for drug delivery applications of nanodiamonds.

  5. Electrochromic in conjugated polymers

    International Nuclear Information System (INIS)

    Picado Valenzuela, Alfredo

    2007-01-01

    This revision considered object the description of one of the materials with the greatest potential in the field of electrochromic (mainly in the visible region): the conjugated polymers (CP), area of enormous potential both now and in a short time ahead. The CP are insulating materials and organic semiconductors in a state not doped. They can be doped positively or negatively being observed a significant increase in the conductivity and being generated a color change in these materials. The understanding of how optical properties vary based on the chemical structure of the polymer or its mixtures and more precisely of the alternatives that can be entered into the conjugated system or π system to obtain a material that besides to be flexible, environmentally stable, presents the colored states. The revision was centred chiefly in the polypyrrole (Ppy), the polythiophene (PTh) and their derivatives such as poly (3.4-ethylenedioxythiophene) (PEDOT). The advantage of using monomers with variable structure, to adjust the composition of the copolymer, or to blend with the PC, allows to obtain a variety of colored states that can be modulated through the visible spectrum and even with applications to wavelengths outside of this region. Because the PC presented at least two different colored states can be varied continuously as a function of the voltage applied. In some cases, they may submit multicoloured statements, which offers a range of possibilities for their application in flexible electronic devices type screens and windows. Applications include smart windows, camouflage clothing and data screens. This type of material is emerging as one of the substitutes of the traditional inorganic semiconductor, with the advantage of its low cost, high flexibility and the possibility to generate multiple colors through the handling of the monomers in the structure and control of energy of his band gap. (author) [es

  6. Non-classical light emission from single conjugated polymers

    Science.gov (United States)

    Hollars, Christopher; Lane, Stephen; Huser, Thomas

    2002-03-01

    Photon-antibunching from single, isolated molecules of collapsed-chain poly[2-methoxy,5-(2’-ethyl-hexyloxy)-p-phenylene-vinylene] (MEH-PPV) has been observed using confocal microscopy techniques. Efficient inter-segment energy transfer in collapsed-chain conjugated polymers leads to emission from an average of only 2-3 active sites on a polymer chain that is composed of hundreds of quasi-chromophores. These few centers consist of the segments with the lowest excitation energy and are supplied by the efficient light-harvesting and energy transfer of the surrounding higher-energy segments. This effect depends on the conformation of the polymer molecules, which is controlled by solvent polarity. These results provide new insight into the controversial photophysics of conjugated polymers and their application in optoelectronic devices.

  7. Block-conjugate-gradient method

    International Nuclear Information System (INIS)

    McCarthy, J.F.

    1989-01-01

    It is shown that by using the block-conjugate-gradient method several, say s, columns of the inverse Kogut-Susskind fermion matrix can be found simultaneously, in less time than it would take to run the standard conjugate-gradient algorithm s times. The method improves in efficiency relative to the standard conjugate-gradient algorithm as the fermion mass is decreased and as the value of the coupling is pushed to its limit before the finite-size effects become important. Thus it is potentially useful for measuring propagators in large lattice-gauge-theory calculations of the particle spectrum

  8. Molecule Matters van der Waals Molecules

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

  9. Facile Synthesis of Three-Dimensional Heteroatom-Doped and Hierarchical Egg-Box-Like Carbons Derived from Moringa oleifera Branches for High-Performance Supercapacitors.

    Science.gov (United States)

    Cai, Yijin; Luo, Ying; Xiao, Yong; Zhao, Xiao; Liang, Yeru; Hu, Hang; Dong, Hanwu; Sun, Luyi; Liu, Yingliang; Zheng, Mingtao

    2016-12-07

    In this paper, we demonstrate that Moringa oleifera branches, a renewable biomass waste with abundant protein content, can be employed as novel precursor to synthesize three-dimensional heteroatom-doped and hierarchical egg-box-like carbons (HEBLCs) by a facile room-temperature pretreatment and direct pyrolysis process. The as-prepared HEBLCs possess unique egg-box-like frameworks, high surface area, and interconnected porosity as well as the doping of heteroatoms (oxygen and nitrogen), endowing its excellent electrochemical performances (superior capacity, high rate capability, and outstanding cycling stability). Therefore, the resultant HEBLC manifests a maximum specific capacitance of 355 F g -1 at current density of 0.5 A g -1 and remarkable rate performance. Moreover, 95% of capacitance retention of HEBLCs can be also achieved after 20 000 charge-discharge cycles at an extremely high current density (20 A g -1 ), indicating a prominent cycling stability. Furthermore, the as-assembled HEBLC//HEBLC symmetric supercapacitor displays a superior energy density of 20 Wh kg -1 in aqueous electrolyte and remarkable capacitance retention (95.6%) after 10 000 charge-discharge cycles. This work provides an environmentally friendly and reliable method to produce higher-valued carbon nanomaterials from renewable biomass wastes for energy storage applications.

  10. The effect of halogen hetero-atoms on the vapor pressures and thermodynamics of polycyclic aromatic compounds measured via the Knudsen effusion technique

    International Nuclear Information System (INIS)

    Goldfarb, Jillian L.; Suuberg, Eric M.

    2008-01-01

    Knowledge of vapor pressures of high molar mass organics is essential to predicting their behavior in combustion systems as well as their fate and transport within the environment. This study involved polycyclic aromatic compounds (PACs) containing halogen hetero-atoms, including bromine and chlorine. The vapor pressures of eight PACs, ranging in molar mass from (212 to 336) g . mol -1 , were measured using the isothermal Knudsen effusion technique over the temperature range of (296 to 408) K. These compounds included those with few or no data available in the literature, namely: 1,4-dibromonaphthalene, 5-bromoacenaphthene, 9-bromoanthracene, 1,5-dibromoanthracene, 9,10-dibromoanthracene, 2-chloroanthracene, 9,10-dichloroanthracene, and 1-bromopyrene. Enthalpies of sublimation of these compounds were determined via application of the Clausius-Clapeyron equation. An analysis is presented on the effects of the addition of halogen hetero-atoms to pure polycyclic aromatic hydrocarbons using these data as well as available literature data. As expected, the addition of halogens onto these PACs increases their enthalpies of sublimation and decreases their vapor pressures as compared to the parent compounds

  11. Sulfur- and nitrogen-containing phenol-formaldehyde co-resites for probing the thermal behaviour of heteroatomic forms in solid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.; Sirkecioglu, O.; Andresen, J.M.; Brown, S.D.; Hall, P.J.; Snape, C.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

    1996-09-01

    In order to probe the formation of sulfur- and nitrogen-containing gases during the pyrolysis and combustion of coals and other solid fuels, non-softening model substrates are required. In this respect phenol-formaldehyde (PF) resins are ideal since they readily facilitate the incorporation of individual heteroatomic functions into a highly crosslinked matrix. A series of sulfur- and nitrogen-containing co-resites were prepared using phenol with, as the second component, thiophene, dibenzothiophene, diphenylsulfide, benzyl phenyl sulfide, thioanisole, 8-hydroxyquinoline and 2-hydroxycarbazole. A mole ratio of 3:1 (phenol: heteroatom-containing component) was used. Resoles containing diphenyldisulfide were also prepared but, due to the comparable bond strengths of the S-S and C-O linkages, a curing temperature of only 130{degree}C was used to avoid cleavage of the disulfide bond. The virtually complete elimination of ether and methylol functions from the resoles by curing at 200{degree}C was monitored by solid-state {sup 13}C nuclear magnetic resonance spectroscopy. The resultant resites were also characterized by sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy, X-ray photoelectron spectroscopy and differential scanning calorimetry. Simple air oxidation was found to selectively convert the aliphatic-bound sulfur to a mixture of sulfones and sulfoxides. Applications of the resites in fuel science are described.

  12. 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.

  13. Quantification of residual solvents in antibody drug conjugates using gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Medley, Colin D., E-mail: medley.colin@gene.com [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States); Kay, Jacob [Research Pharmaceutical Services, 520 Virginia Dr. Fort, Washington, PA (United States); Li, Yi; Gruenhagen, Jason; Yehl, Peter; Chetwyn, Nik P. [Genentech Inc., Small Molecule Pharmaceutical Sciences, 1 DNA Way, South San Francisco, CA 94080 (United States)

    2014-11-19

    Highlights: • Sensitive residual solvents detection in ADCs. • 125 ppm QL for common conjugation solvents. • Generic and validatable method. - Abstract: The detection and quantification of residual solvents present in clinical and commercial pharmaceutical products is necessary from both patient safety and regulatory perspectives. Head-space gas chromatography is routinely used for quantitation of residual solvents for small molecule APIs produced through synthetic processes; however residual solvent analysis is generally not needed for protein based pharmaceuticals produced through cultured cell lines where solvents are not introduced. In contrast, antibody drug conjugates and other protein conjugates where a drug or other molecule is covalently bound to a protein typically use solvents such as N,N-dimethylacetamide (DMA), N,N‑dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or propylene glycol (PG) to dissolve the hydrophobic small molecule drug for conjugation to the protein. The levels of the solvent remaining following the conjugation step are therefore important to patient safety as these parental drug products are introduced directly into the patients bloodstream. We have developed a rapid sample preparation followed by a gas chromatography separation for the detection and quantification of several solvents typically used in these conjugation reactions. This generic method has been validated and can be easily implemented for use in quality control testing for clinical or commercial bioconjugated products.

  14. Entanglements in Conjugated Polymers

    Science.gov (United States)

    Xie, Renxuan; Lee, Youngmin; Aplan, Melissa; Caggiano, Nick; Gomez, Enrique; Colby, Ralph

    Conjugated polymers, such as poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly-((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(thiophen-5-yl)-2,1,3-benzothiadiazole]-2',2''-diyl) (PFTBT), are widely used as hole and electron transport materials in a variety of electronic devices. However, fundamental knowledge regarding chain entanglements and nematic-to-isotropic transition is still lacking and are crucial to maximize charge transport properties. A systematic melt rheology study on P3HT with various molecular weights and regio regularities was performed. We find that the entanglement molecular weight Me is 5.0 kg/mol for regiorandom P3HT, but the apparent Me for regioregular P3HT is significantly higher. The difference is postulated to arise from the presence of a nematic phase only in regioregular P3HT. Analogously, PFTBT shows a clear rheological signature of the nematic-to-isotropic transition as a reversible sharp transition at 278 C. Shearing of this nematic phase leads to anisotropic crystalline order in PFTBT. We postulate that aligning the microstructure will impact charge transport and thereby advance the field of conducting polymers. National Science Foundation.

  15. Protein carriers of conjugate vaccines

    Science.gov (United States)

    Pichichero, Michael E

    2013-01-01

    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

  16. Conjugated Fatty Acid Synthesis

    Science.gov (United States)

    Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

    2012-01-01

    Conjugated linolenic acids (CLNs), 18:3 Δ9,11,13, lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ9,12,15). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ9cis,11trans,13cis) or α-eleostearic acid (18:3 Δ9cis,11trans,13trans). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation. PMID:22451660

  17. Hacking into the granuloma: could antibody antibiotic conjugates be developed for TB?

    Science.gov (United States)

    Ekins, Sean

    2014-12-01

    Alternatives to small molecule or vaccine approaches to treating tuberculosis are rarely discussed. Attacking Mycobacterium tuberculosis in the granuloma represents a challenge. It is proposed that the conjugation of small molecules onto a monoclonal antibody that recognizes macrophage or lymphocytes cell surface receptors, might be a way to target the bacteria in the granuloma. This antibody drug conjugate approach is currently being used in 2 FDA approved targeted cancer therapies. The pros and cons of this proposal for further research are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  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. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi

    2017-03-16

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  20. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi; Piwonski, Hubert Marek; Michinobu, Tsuyoshi

    2017-01-01

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  1. Bispecific small molecule–antibody conjugate targeting prostate cancer

    Science.gov (United States)

    Kim, Chan Hyuk; Axup, Jun Y.; Lawson, Brian R.; Yun, Hwayoung; Tardif, Virginie; Choi, Sei Hyun; Zhou, Quan; Dubrovska, Anna; Biroc, Sandra L.; Marsden, Robin; Pinstaff, Jason; Smider, Vaughn V.; Schultz, Peter G.

    2013-01-01

    Bispecific antibodies, which simultaneously target CD3 on T cells and tumor-associated antigens to recruit cytotoxic T cells to cancer cells, are a promising new approach to the treatment of hormone-refractory prostate cancer. Here we report a site-specific, semisynthetic method for the production of bispecific antibody-like therapeutics in which a derivative of the prostate-specific membrane antigen-binding small molecule DUPA was selectively conjugated to a mutant αCD3 Fab containing the unnatural amino acid, p-acetylphenylalanine, at a defined site. Homogeneous conjugates were generated in excellent yields and had good solubility. The efficacy of the conjugate was optimized by modifying the linker structure, relative binding orientation, and stoichiometry of the ligand. The optimized conjugate showed potent and selective in vitro activity (EC50 ∼100 pM), good serum half-life, and potent in vivo activity in prophylactic and treatment xenograft mouse models. This semisynthetic approach is likely to be applicable to the generation of additional bispecific agents using drug-like ligands selective for other cell-surface receptors. PMID:24127589

  2. Conjugated polymer zwitterions and solar cells comprising conjugated polymer zwitterions

    Science.gov (United States)

    Emrick, Todd; Russell, Thomas; Page, Zachariah; Liu, Yao

    2018-06-05

    A conjugated polymer zwitterion includes repeating units having structure (I), (II), or a combination thereof ##STR00001## wherein Ar is independently at each occurrence a divalent substituted or unsubstituted C3-30 arylene or heteroarylene group; L is independently at each occurrence a divalent C1-16 alkylene group, C6-30arylene or heteroarylene group, or alkylene oxide group; and R1 is independently at each occurrence a zwitterion. A polymer solar cell including the conjugated polymer zwitterion is also disclosed.

  3. Preparation, Single-Molecule Manipulation, and Energy Transfer Investigation of a Polyfluorene-graft-DNA polymer.

    Science.gov (United States)

    Madsen, Mikael; Christensen, Rasmus S; Krissanaprasit, Abhichart; Bakke, Mette R; Riber, Camilla F; Nielsen, Karina S; Zelikin, Alexander N; Gothelf, Kurt V

    2017-08-04

    Conjugated polymers have been intensively studied due to their unique optical and electronic properties combined with their physical flexibility and scalable bottom up synthesis. Although the bulk qualities of conjugated polymers have been extensively utilized in research and industry, the ability to handle and manipulate conjugated polymers at the nanoscale lacks significantly behind. Here, the toolbox for controlled manipulation of conjugated polymers was expanded through the synthesis of a polyfluorene-DNA graft-type polymer (poly(F-DNA)). The polymer possesses the characteristics associated with the conjugated polyfluorene backbone, but the protruding single-stranded DNA provides the material with an exceptional addressability. This study demonstrates controlled single-molecule patterning of poly(F-DNA), as well as energy transfer between two different polymer-DNA conjugates. Finally, highly efficient DNA-directed quenching of polyfluorene fluorescence was shown. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Characterization of hapten-protein conjugates: antibody generation and immunoassay development for chlorophenoxyacetic acid pesticides.

    Science.gov (United States)

    Boro, Robin C; Singh, K Vikas; Suri, C Raman

    2009-01-01

    The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1-500 nglmL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

  5. Docosahexaenoyl serotonin, an endogenously formed n-3 fatty acid-serotonin conjugate has anti-inflammatory properties by attenuating IL-23–IL-17 signaling in macrophages

    NARCIS (Netherlands)

    Poland, Mieke; Klooster, ten Jean Paul; Wang, Zheng; Pieters, Raymond; Boekschoten, Mark; Witkamp, Renger; Meijerink, Jocelijn

    2016-01-01

    Conjugates of fatty acids and amines, including endocannabinoids, are known to play important roles as endogenous signaling molecules. Among these, the ethanolamine conjugate of the n-3 poly unsaturated long chain fatty acid (PUFA) docosahexaenoic acid (22:6n-3) (DHA) was shown to possess strong

  6. Docosahexaenoyl serotonin, an endogenously formed n-3 fatty acid-serotonin conjugate has anti-inflammatory properties by attenuating IL-23-IL-17 signaling in macrophages

    NARCIS (Netherlands)

    Poland, Mieke; Ten Klooster, Jean Paul; Wang, Zheng; Pieters, Raymond; Boekschoten, Mark; Witkamp, Renger; Meijerink, Jocelijn

    2016-01-01

    Conjugates of fatty acids and amines, including endocannabinoids, are known to play important roles as endogenous signaling molecules. Among these, the ethanolamine conjugate of the n-3 poly unsaturated long chain fatty acid (PUFA) docosahexaenoic acid (22:6n-3) (DHA) was shown to possess strong

  7. Docosahexaenoyl Serotonin, an endogenously formed n-3 fatty acid-serotonin conjugate, has anti-inflammatory properties by attenuating IL23–IL17 signalling in macrophages

    NARCIS (Netherlands)

    Poland, M.C.R.; Klooster, ten Jean Paul; Wang, Zheng; Pieters, Raymond; Boekschoten, M.V.; Witkamp, R.F.; Meijerink, J.

    2016-01-01

    Conjugates of fatty acids and amines, including endocannabinoids, are known to play important roles as endogenous signalling molecules. Among these, the ethanolamine conjugate of the n-3 poly unsaturated long chain fatty acid (PUFA) docosahexaenoic acid (22:6n-3) (DHA) was shown to possess strong

  8. Recyclable surfaces for amine conjugation chemistry via redox reaction

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Inseong; Yeo, Woon Seok [Dept. of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul (Korea, Republic of); Bae, Se Won [Green Materials and Process Group, Research Institute of Sustainable Manufacturing System, Korea Institute of Industrial Technology, Cheonan (Korea, Republic of)

    2017-02-15

    In this study, we extended this strategy to present a switchable surface that allows surface functionalization and removal of functional groups repeatedly. The substrate presenting a benzoquinone acid group is first used to immobilize with an amine-containing (bio)molecule using well-known conjugation chemistry. The benzoquinone group is then converted to the corresponding hydroquinone by treating with a reducing agent. We have described a strategy for the dynamic control of surface properties with recyclability via a simple reduction/ oxidation reaction. A stimuli-responsive quinone derivative was harnessed for the repeated immobilization and release of (bio)molecules, and thus, for the repeated dynamic change of the surface properties according to the characteristics of the immobilized (bio)molecules.

  9. PSMA-targeted bispecific Fab conjugates that engage T cells.

    Science.gov (United States)

    Patterson, James T; Isaacson, Jason; Kerwin, Lisa; Atassi, Ghazi; Duggal, Rohit; Bresson, Damien; Zhu, Tong; Zhou, Heyue; Fu, Yanwen; Kaufmann, Gunnar F

    2017-12-15

    Bioconjugate formats provide alternative strategies for antigen targeting with bispecific antibodies. Here, PSMA-targeted Fab conjugates were generated using different bispecific formats. Interchain disulfide bridging of an αCD3 Fab enabled installation of either the PSMA-targeting small molecule DUPA (SynFab) or the attachment of an αPSMA Fab (BisFab) by covalent linkage. Optimization of the reducing conditions was critical for selective interchain disulfide reduction and good bioconjugate yield. Activity of αPSMA/CD3 Fab conjugates was tested by in vitro cytotoxicity assays using prostate cancer cell lines. Both bispecific formats demonstrated excellent potency and antigen selectivity. Copyright © 2017. Published by Elsevier Ltd.

  10. Preparation of Conjugates of Cytotoxic Lupane Triterpenes with Biotin.

    Science.gov (United States)

    Soural, Miroslav; Hodon, Jiri; Dickinson, Niall J; Sidova, Veronika; Gurska, Sona; Dzubak, Petr; Hajduch, Marian; Sarek, Jan; Urban, Milan

    2015-12-16

    To better understand the mechanism of action of antitumor triterpenes, we are developing methods to identify their molecular targets. A promising method is based on combination of quantitative proteomics with SILAC and uses active compounds anchored to magnetic beads via biotin-streptavidin interaction. We developed a simple and fast solid-phase synthetic technique to connect terpenes to biotin through a linker. Betulinic acid was biotinylated from three different conjugation sites for use as a standard validation tool since many molecular targets of this triterpene are already known. Then, a set of four other cytotoxic triterpenoids was biotinylated. Biotinylated terpenes were similarly cytotoxic to their nonbiotinylated parents, which suggests that the target identification should not be influenced by linker or biotin. The developed solid-phase synthetic approach is the first attempt to use solid-phase synthesis to connect active triterpenes to biotin and is applicable as a general procedure for routine conjugation of triterpenes with other molecules of choice.

  11. Molecule Matters van der Waals Molecules

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Molecule Matters van der Waals Molecules - Rg•••HF Complexes are Debye Molecules! E Arunan. Feature Article Volume 15 Issue 7 July 2010 pp 667-674. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Ti-Catalyzed Hydroamination for the Synthesis of Amine-Containing π-Conjugated Materials.

    Science.gov (United States)

    Hao, Han; Thompson, Kyle A; Hudson, Zachary M; Schafer, Laurel L

    2018-04-11

    A series of conjugated enamines were prepared by Ti catalyzed anti-Markovnikov hydroamination. The synthetic route is efficient with yields of up to 94 % and the 100 % atom efficiency of the reaction means that these products are easily isolated and purified. Due to the extended conjugated system, the enamine tautomers were observed exclusively in both solid and solution phases, as determined by X-ray crystallography and NMR spectroscopy. These new conjugated molecules, with N incorporated into the backbone, show interesting photophysical properties including photo-luminescent quantum yields of up to 0.26. Notably, through the incorporation of B to give a donor-acceptor π-conjugated system, a redshift of approximately 100 nm is observed for the emission maximum along with the anticipated solvatochromic shifts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Conjugated Polymer with Intrinsic Alkyne Units for Synergistically Enhanced Raman Imaging in Living Cells.

    Science.gov (United States)

    Li, Shengliang; Chen, Tao; Wang, Yunxia; Liu, Libing; Lv, Fengting; Li, Zhiliang; Huang, Yanyi; Schanze, Kirk S; Wang, Shu

    2017-10-16

    Development of Raman-active materials with enhanced and distinctive Raman vibrations in the Raman-silent region (1800-2800 cm -1 ) is highly required for specific molecular imaging of living cells with high spatial resolution. Herein, water-soluble cationic conjugated polymers (CCPs), poly(phenylene ethynylene) (PPE) derivatives, are explored for use as alkyne-state-dependent Raman probes for living cell imaging due to synergetic enhancement effect of alkyne vibrations in Raman-silent region compared to alkyne-containing small molecules. The enhanced alkyne signals result from the integration of alkyne groups into the rigid backbone and the delocalized π-conjugated structure. PPE-based conjugated polymer nanoparticles (CPNs) were also prepared as Raman-responsive nanomaterials for distinct imaging application. This work opens a new way into the development of conjugated polymer materials for enhanced Raman imaging. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Albumin–Polymer–Drug Conjugates: Long Circulating, High Payload Drug Delivery Vehicles

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford; Zuwala, Kaja; Pilgram, Oliver

    2016-01-01

    Albumin is an exquisite tool of nature used in biomedicine to achieve long blood residence time for drugs, but the payload it can carry is typically limited to one molecule per protein. In contrast, synthetic macromolecular prodrugs contain multiple copies of drugs per polymer chain but offer only...... a marginal increase in the circulation lifetime of the drugs. We combine the benefits of the two platforms and at the same time overcome their respective limitations. Specifically, we develop the synthesis of albumin–polymer–drug conjugates to obtain long circulating, high payload drug delivery vehicles....... In vivo data validate that albumin endows the conjugate with a blood residence time similar to that of the protein and well exceeding that of the polymer. Therapeutic activity of the conjugates is validated using prodrugs of panobinostat, an HIV latency reversal agent, in which case the conjugates matched...

  15. Integrating Protein Engineering and Bioorthogonal Click Conjugation for Extracellular Vesicle Modulation and Intracellular Delivery.

    Directory of Open Access Journals (Sweden)

    Ming Wang

    Full Text Available Exosomes are small, cell-secreted vesicles that transfer proteins and genetic information between cells. This intercellular transmission regulates many physiological and pathological processes. Therefore, exosomes have emerged as novel biomarkers for disease diagnosis and as nanocarriers for drug delivery. Here, we report an easy-to-adapt and highly versatile methodology to modulate exosome composition and conjugate exosomes for intracellular delivery. Our strategy combines the metabolic labeling of newly synthesized proteins or glycan/glycoproteins of exosome-secreting cells with active azides and bioorthogonal click conjugation to modify and functionalize the exosomes. The azide-integrated can be conjugated to a variety of small molecules and proteins and can efficiently deliver conjugates into cells. The metabolic engineering of exosomes diversifies the chemistry of exosomes and expands the functions that can be introduced into exosomes, providing novel, powerful tools to study the roles of exosomes in biology and expand the biomedical potential of exosomes.

  16. Conjugal Pairing in Escherichia Coli

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Conjugal Pairing in Escherichia Coli. Joshua Lederberg. Classics Volume 13 Issue 8 August 2008 pp 793-794. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/013/08/0793-0794 ...

  17. Orderings for conjugate gradient preconditionings

    Science.gov (United States)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  18. Bacteriophytochromes control conjugation in Agrobacterium fabrum.

    Science.gov (United States)

    Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

    2016-08-01

    Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. REVIEW ARTICLE Conjugated Hyperbilirubinaemia in Early Infancy ...

    African Journals Online (AJOL)

    REVIEW ARTICLE Conjugated Hyperbilirubinaemia in Early Infancy. AOK Johnson. Abstract. Conjugated hyperbilirubinaemia exists when the conjugated serum bilirubin level is more than 2 mg/dl or more than 20 per cent of the total serum bilirubin. It is always pathological in early infancy. The causes are many and diverse ...

  20. Purification of SUMO conjugating enzymes and kinetic analysis of substrate conjugation

    Science.gov (United States)

    Yunus, Ali A.; Lima, Christopher D.

    2009-01-01

    SUMO conjugation to protein substrates requires the concerted action of a dedicated E2 ubiquitin conjugation enzyme (Ubc9) and associated E3 ligases. Although Ubc9 can directly recognize and modify substrate lysine residues that occur within a consensus site for SUMO modification, E3 ligases can redirect specificity and enhance conjugation rates during SUMO conjugation in vitro and in vivo. In this chapter, we will describe methods utilized to purify SUMO conjugating enzymes and model substrates which can be used for analysis of SUMO conjugation in vitro. We will also describe methods to extract kinetic parameters during E3-dependent or E3-independent substrate conjugation. PMID:19107417

  1. Bioanalysis of antibody-drug conjugates: American Association of Pharmaceutical Scientists Antibody-Drug Conjugate Working Group position paper.

    Science.gov (United States)

    Gorovits, Boris; Alley, Stephen C; Bilic, Sanela; Booth, Brian; Kaur, Surinder; Oldfield, Phillip; Purushothama, Shobha; Rao, Chetana; Shord, Stacy; Siguenza, Patricia

    2013-05-01

    Antibody-drug conjugates (ADCs) typically consist of a cytotoxic drug covalently bound to an antibody by a linker. These conjugates have the potential to substantially improve efficacy and reduce toxicity compared with cytotoxic small-molecule drugs. Since ADCs are generally complex heterogeneous mixtures of multiple species, these novel therapeutic products present unique bioanalytical challenges. The growing number of ADCs being developed across the industry suggests the need for alignment of the bioanalytical methods or approaches used to assess the multiple species and facilitate consistent interpretation of the bioanalytical data. With limited clinical data, the current strategies that can be used to provide insight into the relationship between the multiple species and the observed clinical safety and efficacy are still evolving. Considerations of the bioanalytical strategies for ADCs based on the current industry practices that take into account the complexity and heterogeneity of ADCs are discussed.

  2. Laboratory Anion Chemistry: Implications for the DIBs, and a Potential Formation Mechanism for a Known Interstellar Molecule

    Science.gov (United States)

    Eichelberger, B.; Barckholtz, C.; Stepanovic, M.; Bierbaum, V.; Snow, T.

    2002-01-01

    Due to recent interest in molecular anions as possible interstellar species, we have carried out several laboratory studies of anion chemistry. The reactions of the series C(sub n)(sup -); and C(sub n)H(sup -) with H and H2 were studied to address the viability of such species in the diffuse interstellar medium and to address their ability to be carriers of the diffuse interstellar bands (DIBs). These same molecules were also reacted with N and O to show possible heteroatomic products. C(sub m)N(sup - was a particularly stable product from the reaction of C(sub n)(sup -) + N. C3N(sup -) was further reacted with H to study chemistry that could produce HC3N, a known interstellar species. The reactions were done in a flowing afterglow selected ion flow tube apparatus (FA-SIFT). The anions were generated in an electron impact or cold cathode discharge source and the anion of interest was then selected by a quadrupole mass filter. The selected ion was then reacted with the atomic or molecular species in the flow tube and products were detected by another quadrupole. While the C(sub n)(sup -) species do not appear to be viable DIB carriers, their possible presence could provide a mechanism for the formation of known heteroatomic neutral molecules detected in the interstellar medium (ISM).

  3. Formation of high-quality self-assembled monolayers of conjugated dithiols on gold : Base matters

    NARCIS (Netherlands)

    Valkenier, Hennie; Huisman, Everardus H.; Hal, Paul A. van; de Leeuw, Dagobert; Chiechi, Ryan C.; Hummelen, Jan C.

    2011-01-01

    This Article reports a systematic study on the formation of self-assembled monolayers (SAMs) of conjugated molecules for molecular electronic (ME) devices. We monitored the deprotection reaction of acetyl protected dithiols of oligophenylene ethynylenes (OPEs) in solution using two different bases

  4. Synthesis and biological evaluations of cytotoxic and antiangiogenic triterpenoids-jacaranone conjugates

    DEFF Research Database (Denmark)

    Sun, Hua; Yue, Partick Y. K.; Wang, Shao Rong

    2016-01-01

    showed that these conjugates are more potent in both cytotoxic and antiangiogenic assays than their corresponding parent molecules, and are also selectively more active against melanoma cells B16 and metastatic B16BL6 than the two other cancer cell lines (A549 and MCF-7) tested. The predicted...

  5. Electric-Field Control of Interfering Transport Pathways in a Single-Molecule Anthraquinone Transistor

    NARCIS (Netherlands)

    Koole, Max; Thijssen, Jos M.; Valkenier, Hennie; Hummelen, Jan C.; van der Zant, Herre S. J.

    It is understood that molecular conjugation plays an important role in charge transport through single-molecule junctions. Here, we investigate electron transport through an anthraquinone based single-molecule three-terminal device. With the use of an electric-field induced by a gate electrode, the

  6. Inhibiting prolyl isomerase activity by hybrid organic-inorganic molecules containing rhodium(II) fragments.

    Science.gov (United States)

    Coughlin, Jane M; Kundu, Rituparna; Cooper, Julian C; Ball, Zachary T

    2014-11-15

    A small molecule containing a rhodium(II) tetracarboxylate fragment is shown to be a potent inhibitor of the prolyl isomerase FKBP12. The use of small molecules conjugates of rhodium(II) is presented as a general strategy for developing new protein inhibitors based on distinct structural and sequence features of the enzyme active site. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Electric-Field Control of Interfering Transport Pathways in a Single-Molecule Anthraquinone Transistor

    Science.gov (United States)

    Koole, Max; Thijssen, Jos M.; Valkenier, Hennie; Hummelen, Jan C.; Zant, Herre S. J. van der

    2015-08-01

    It is understood that molecular conjugation plays an important role in charge transport through single-molecule junctions. Here, we investigate electron transport through an anthraquinone based single-molecule three-terminal device. With the use of an electric-field induced by a gate electrode, the molecule is reduced resulting into a ten-fold increase in the off-resonant differential conductance. Theoretical calculations link the change in differential conductance to a reduction-induced change in conjugation, thereby lifting destructive interference of transport pathways.

  8. Vibrational Coupling in Conjugated π Systems with a view to Optimization of Fluorescence Yield through Phonon Confinement

    OpenAIRE

    O'Neill, Luke; Lynch, Patrick; McNamara, Mary; Byrne, Hugh J.

    2005-01-01

    A series of π conjugated systems were studied by absorption, photoluminescence and vibrational spectroscopy. As is common for these systems, a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transi...

  9. Targeting of [[sup 111]In]biocytin to cultured ovarian adenocarcinoma cells using covalent monoclonal antibody -streptavidin conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Sheldon, K.; Marks, A. (Toronto Univ., ON (Canada). Banting and Best Dept. of Medical Research); Baumal, R. (Hospital for Sick Children, Toronto, ON (Canada). Dept. of Pathology)

    1992-11-01

    Three monoclonal antibodies (mAb) directed against the human ovarian adenocarcinoma cell line HEY, were substituted with maleimide and covalently bonded to thiolated streptavidin. The conjugates were separated from unreacted reagents by successive affinity chromatography on protein A-Sepharose and iminobiotin columns. Purified conjugates consisted of an immunoglobulin (Ig) monomer bound to a streptavidin tetramer through a covalent bond between the Ig molecule and one of the streptavidin subunits. The conjugates were able to specifically target [[sup 111]In]biocytin to HEY cells in vitro in the presence of human serum and ascitic fluid from ovarian cancer patients. (Author).

  10. Hemoglobin Detection on a Microfluidic Sensor Chip with a Partially Conjugated Polymer

    International Nuclear Information System (INIS)

    Eo, Soo Han; Won, Kwang Jae; Song, Simon; Yoon, Bora; Kim, Jong Man

    2010-01-01

    The development of efficient chemosensors based on the conjugated polymers has been the central focus of a large number of recent research programs. The presence of extensively delocalized electrons and conformational restrictions of the backbone structures make conjugated polymers attractive sensory materials. In these polymers, molecular recognition events influence electronic absorption and emission properties. Thus, a wide variety of conjugated polymer-based sensors have been investigated. However, the majority of the conjugated polymer sensors described to date have been explored in the form of solutions or thin films. Most biologically interesting target molecules, such as proteins, carbohydrates, nucleic acids, or ions, are only soluble in water. Thus, it is desirable to use water-soluble conjugated polymers as sensor matrices. In general, in order to make water-soluble conjugated polymers tedious procedures are required since most synthetic methods developed for this purpose are incompatible with sidechain functionalities. Accordingly, protecting group strategies are required to prepare polymers with requisite functional groups that foster water solubility

  11. High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

    Energy Technology Data Exchange (ETDEWEB)

    Meux, Susan C.; Datta, Ankona; Hooker, Jacob M.; Botta, Mauro; Francis, Matthew B.; Aime, Silvio; Raymond, Kenneth N.

    2007-08-29

    High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) there is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups.

  12. Fabrication of 3D heteroatom-doped porous carbons from self-assembly of chelate foams via a solid state method

    KAUST Repository

    Wang, Yu; Pan, Ying; Zhu, Liangkui; Guo, Ningning; Wang, Runwei; Zhang, Zongtao; Qiu, Shilun

    2018-01-01

    A novel 3D foam-like porous carbon architectures with homogeneous N doping and unique mesopore-in-macropore structures have been fabricated from metal-organic complex via a facile template-free solid state method, which show high specific surface area (2732 m2 g-1), large pore volume (3.31 cm3 g-1), interconnected hierarchical pore structures with macro/meso/micro multimodal distribution and abundant surface functionality N doping (5.36 wt%). These characteristics afford high catalytic performance for oxygen reduction with an onset potential of 0.98 V (vs RHE) and a half-wave potential of 0.83 V (vs RHE) in alkaline media, which are comparable with those of the commercial 20 wt% Pt/C catalyst and many state-of-the-art noble-metal-free catalysts. These results demonstrate the significant advantages of the unique mesopore-in-macropore porous structures with efficient heteroatom doping, which provides abundant of accessible active sites for highly mass and charge transports. The present work pave a new facile and environmentally benign synthesis strategy for the preparation of 3D porous carbon architectures as efficient electrochemical energy devices and give deep insights into fabricating advanced nanostructured materials.

  13. Heteroatom-enriched and renewable banana-stem-derived porous carbon for the electrochemical determination of nitrite in various water samples

    Science.gov (United States)

    Madhu, Rajesh; Veeramani, Vediyappan; Chen, Shen-Ming

    2014-04-01

    For the first time, high-surface-area (approximately 1465 m2 g-1), highly porous and heteroatom-enriched activated carbon (HAC) was prepared from banana stems (Musa paradisiaca, Family: Musaceae) at different carbonization temperatures of 700, 800 and 900°C (HAC) using a simple and eco-friendly method. The amounts of carbon, hydrogen, nitrogen and sulfur in the HAC are 61.12, 2.567, 0.4315, and 0.349%, respectively. Using X-ray diffraction (XRD), CHNS elemental analysis, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the prepared activated carbon appears amorphous and disordered in nature. Here, we used HAC for an electrochemical application of nitrite (NO2-) sensor to control the environmental pollution. In addition, HAC exhibits noteworthy performance for the highly sensitive determination of nitrite. The limit of detection (LODs) of the nitrite sensor at HAC-modified GCE is 0.07 μM. In addition, the proposed method was applied to determine nitrite in various water samples with acceptable results.

  14. Fabrication of 3D heteroatom-doped porous carbons from self-assembly of chelate foams via a solid state method

    KAUST Repository

    Wang, Yu

    2018-01-09

    A novel 3D foam-like porous carbon architectures with homogeneous N doping and unique mesopore-in-macropore structures have been fabricated from metal-organic complex via a facile template-free solid state method, which show high specific surface area (2732 m2 g-1), large pore volume (3.31 cm3 g-1), interconnected hierarchical pore structures with macro/meso/micro multimodal distribution and abundant surface functionality N doping (5.36 wt%). These characteristics afford high catalytic performance for oxygen reduction with an onset potential of 0.98 V (vs RHE) and a half-wave potential of 0.83 V (vs RHE) in alkaline media, which are comparable with those of the commercial 20 wt% Pt/C catalyst and many state-of-the-art noble-metal-free catalysts. These results demonstrate the significant advantages of the unique mesopore-in-macropore porous structures with efficient heteroatom doping, which provides abundant of accessible active sites for highly mass and charge transports. The present work pave a new facile and environmentally benign synthesis strategy for the preparation of 3D porous carbon architectures as efficient electrochemical energy devices and give deep insights into fabricating advanced nanostructured materials.

  15. Influence of Endo- and Exocyclic Heteroatoms on Stabilities and 1,3-Dipolar Cycloaddition Reactivities of Mesoionic Azomethine Ylides and Imines.

    Science.gov (United States)

    Champagne, Pier Alexandre; Houk, K N

    2017-10-20

    The geometries, stabilities, and 1,3-dipolar cycloaddition reactivities of 24 mesoionic azomethine ylides and imines were investigated using density functional theory calculations at the M06-2X/6-311+G-(d,p)/M06-2X/6-31G-(d) level. The computed structures highlight how the commonly used "aromatic" resonance form should be replaced by two more accurate resonance structures. Stabilities of the dipoles were assessed by various homodesmotic schemes and are consistent with these compounds being nonaromatic. The activation free energies with ethylene or acetylene range from 11.8 to 36.6 kcal/mol. Within each dipole type, the predicted cycloaddition reactivities correlate with the reaction energies and the resonance stabilization energies provided by the various substituents. Endocyclic (X) heteroatoms increase the reactivity of the 1,3-dipoles in the order of O > NH ≅ S, whereas exocyclic (Y) substituents increase it in the order of CH 2 > NH > O > S. Distortion/interaction analysis indicated that the difference in reactivity between differently substituted 1,3-dipoles is driven by distortion, whereas the difference between azomethine ylides and imines is related to lower interaction energies of imines with the dipolarophiles.

  16. Theoretical studies of the structures and local aromaticity of conjugated polycyclic hydrocarbons using three aromatic indices

    Science.gov (United States)

    Sakai, Shogo; Kita, Yuki

    2013-07-01

    The structures and local aromaticity of some conjugated polycyclic hydrocarbons (from the butadienoid, acene, and phenylene series) are studied using ab initio MO and density functional methods. The aromaticities of the molecules are estimated using three indices: the nucleus-independent chemical shift (NICS), the harmonic oscillator model of aromaticity (HOMA), and the index of deviation from aromaticity (IDA). Assessment of the relationships between the structures and the aromatic indices shows that the IDA values correspond best to the characteristics of the conjugated polycyclic hydrocarbon structures.

  17. Polyamine conjugation of curcumin analogues toward the discovery of mitochondria-directed neuroprotective agents.

    Science.gov (United States)

    Simoni, Elena; Bergamini, Christian; Fato, Romana; Tarozzi, Andrea; Bains, Sandip; Motterlini, Roberto; Cavalli, Andrea; Bolognesi, Maria Laura; Minarini, Anna; Hrelia, Patrizia; Lenaz, Giorgio; Rosini, Michela; Melchiorre, Carlo

    2010-10-14

    Mitochondria-directed antioxidants 2-5 were designed by conjugating curcumin congeners with different polyamine motifs as vehicle tools. The conjugates emerged as efficient antioxidants in mitochondria and fibroblasts and also exerted a protecting role through heme oxygenase-1 activation. Notably, the insertion of a polyamine function into the curcumin-like moiety allowed an efficient intracellular uptake and mitochondria targeting. It also resulted in a significant decrease in the cytotoxicity effects. 2-5 are therefore promising molecules for neuroprotectant lead discovery.

  18. A dual platform for selective analyte enrichment and ionization in mass spectrometry using aptamer-conjugated graphene oxide.

    Science.gov (United States)

    Gulbakan, Basri; Yasun, Emir; Shukoor, M Ibrahim; Zhu, Zhi; You, Mingxu; Tan, Xiaohong; Sanchez, Hernan; Powell, David H; Dai, Hongjie; Tan, Weihong

    2010-12-15

    This study demonstrates the use of aptamer-conjugated graphene oxide as an affinity extraction and detection platform for analytes from complex biological media. We have shown that cocaine and adenosine can be selectively enriched from plasma samples and that direct mass spectrometric readouts can be obtained without a matrix and with greatly improved signal-to-noise ratios. Aptamer-conjugated graphene oxide has clear advantages in target enrichment and in generating highly efficient ionization of target molecules for mass spectrometry. These results demonstrate the utility of the approach for analysis of small molecules in real biological samples.

  19. Structure Property Relationships in Organic Conjugated Systems

    OpenAIRE

    O'Neill, Luke

    2008-01-01

    A series of pi(п) conjugated oligomers containing 1 to 6 monomer units were studied by absorption and photoluminescence spectroscopies. The results are discussed and examined with regard to the variation of the optical properties with the increase of effective conjugation length. It was found that there was a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length. The relationships are in good agreement with the si...

  20. 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...... polymerization method for industrial production of polymers. Several DArP protocols have been employed for the synthesis of PPDTBT leading to polymers with high structural regularity and photovoltaic performances comparable with the same materials synthesized via Stille cross-coupling polymerization...

  1. Novel ?-cyclodextrin?eosin conjugates

    OpenAIRE

    Benkovics, G?bor; Afonso, Damien; Darcsi, Andr?s; B?ni, Szabolcs; Conoci, Sabrina; Fenyvesi, ?va; Szente, Lajos; Malanga, Milo; Sortino, Salvatore

    2017-01-01

    Eosin B (EoB) and eosin Y (EoY), two xanthene dye derivatives with photosensitizing ability were prepared in high purity through an improved synthetic route. The dyes were grafted to a 6-monoamino-β-cyclodextrin scaffold under mild reaction conditions through a stable amide linkage using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The molecular conjugates, well soluble in aqueous medium, were extensively characterized by 1D and 2D NMR spectroscopy an...

  2. Test of charge conjugation invariance

    International Nuclear Information System (INIS)

    Nefkens, B.M.K.; Prakhov, S.; Gaardestig, A.; Clajus, M.; Marusic, A.; McDonald, S.; Phaisangittisakul, N.; Price, J.W.; Starostin, A.; Tippens, W.B.; Allgower, C.E.; Spinka, H.; Bekrenev, V.; Koulbardis, A.; Kozlenko, N.; Kruglov, S.; Lopatin, I.; Briscoe, W.J.; Shafi, A.; Comfort, J.R.

    2005-01-01

    We report on the first determination of upper limits on the branching ratio (BR) of η decay to π 0 π 0 γ and to π 0 π 0 π 0 γ. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(η→π 0 π 0 γ) -4 at the 90% confidence level, in support of C invariance of isoscalar electromagnetic interactions of the light quarks. We have also measured BR(η→π 0 π 0 π 0 γ) -5 at the 90% confidence level, in support of C invariance of isovector electromagnetic interactions

  3. Base-catalyzed tandem Michael/dehydro-Diels-Alder reaction of α,α-dicyanoolefins with electron-deficient 1,3-conjugated enynes: a facile entry to angularly fused polycycles.

    Science.gov (United States)

    Zhang, Mingrui; Zhang, Junliang

    2014-01-07

    Angularly fused carbocyclic frameworks and their heteroatom-substituted analogues exist in many natural products that display a broad and interesting range of biological activities. Preparation of polycyclic products by cycloaddition reactions have been the long-standing hot topic in the synthetic community. Dehydro-Diels-Alder (DDA) reactions are one class of dehydropericyclic reactions that are derived conceptually by systematic removal of hydrogen atom pairs. A base-promoted tandem Michael addition and DDA reaction of α,α-dicyanoolefins with electron-deficient 1,3-conjugated enynes was realized in which a DDA reaction takes place between the arylalkynes and electron-deficient tetrasubstituted olefin. The control experiments support the stepwise anionic reaction pathway rather than the concerted reaction pathway. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Biotin/Folate-decorated Human Serum Albumin Nanoparticles of Docetaxel: Comparison of Chemically Conjugated Nanostructures and Physically Loaded Nanoparticles for Targeting of Breast Cancer.

    Science.gov (United States)

    Nateghian, Navid; Goodarzi, Navid; Amini, Mohsen; Atyabi, Fatemeh; Khorramizadeh, Mohammad Reza; Dinarvand, Rassoul

    2016-01-01

    Docetaxel (DTX) is a widely used chemotherapeutic agent with very low water solubility. Conjugation of DTX to human serum albumin (HSA) is an effective way to increase its water solubility. Attachment of folic acid (FA) or biotin as targeting moieties to DTX-HSA conjugates may lead to active targeting and specific uptake by cancer cells with overexpressed FA or biotin receptors. In this study, FA or biotin molecules were attached to DTX-HSA conjugates by two different methods. In one method, FA or biotin molecules were attached to remaining NH2 residues of HSA in DTX-HSA conjugate by covalent bonds. In the second method, HSA-FA or HSA-biotin conjugates were synthesized separately and then combined by DTX-HSA conjugate in proper ratio to prepare nanoparticles containing DTX-HSA plus HSA-FA or HSA-biotin. Cell viability of different nanoparticle was evaluated on MDA-MB-231 (folate receptor positive), A549 (folate receptor negative), and 4T1 (biotin receptor positive) and showed superior cytotoxicity compared with free docetaxel (Taxotere). In vivo studies of DTX-HSA-FA and DTX-HSA-biotin conjugates in BULB/c mice, tumorized by 4T1 cell line, showed the conjugates prepared in this study were more powerful in the reduction in tumor size and increasing the survival rate when compared to free docetaxel. © 2015 John Wiley & Sons A/S.

  5. Conjugated polymers developed from alkynes

    Institute of Scientific and Technical Information of China (English)

    Yajing Liu; Jacky W.Y.Lam; Ben Zhong Tang

    2015-01-01

    The numerous merits of conjugated polymers(CPs) have encouraged scientists to develop a variety of synthetic routes to CPs with diverse structures and functionalities. Among the large scope of substrates,alkyne plays an important role in constructing polymers with conjugated backbones. In addition to some well-developed reactions including Glaser–Hay and Sonogashira coupling, azide/thiol-yne click reaction and cyclotrimerization, some novel alkyne-based reactions have also been explored such as oxidative polycoupling, decarbonylative polycoupling and multicomponent tandem polymerizations. his review focuses on the recent progress on the synthetic methodology of CPs in the last ive years using monomers with two or more triple bonds and some of their high-technological applications. Selected examples of materials properties of these CPs are given in this review, such as luorescence response to chemical or physical stimuli, magnetism, white light emission, cell imaging and bioprobing. Finally, a short perspective is raised in regard to the outlook of the preparation methodologies, functionalities as well as potential applications of CPs in the future.

  6. 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 materials. We have used PDS to measure the optical absorption spectra of the 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.

  7. Subgap absorption in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, M.; Seager, C.H. (Sandia National Labs., Albuquerque, NM (USA)); McBranch, D.; Heeger, A.J. (California Univ., Santa Barbara, CA (USA)); Baker, G.L. (Bell Communications Research, Inc., Red Bank, NJ (USA))

    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 < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the 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 refs., 4 figs.

  8. One-Step Protein Conjugation to Upconversion Nanoparticles.

    Science.gov (United States)

    Lu, Jie; Chen, Yinghui; Liu, Deming; Ren, Wei; Lu, Yiqing; Shi, Yu; Piper, James; Paulsen, Ian; Jin, Dayong

    2015-10-20

    The emerging upconversion nanoparticles offer a fascinating library of ultrasensitive luminescent probes for a range of biotechnology applications from biomarker discovery to single molecule tracking, early disease diagnosis, deep tissue imaging, and drug delivery and therapies. The effective bioconjugation of inorganic nanoparticles to the molecule-specific proteins, free of agglomeration, nonspecific binding, or biomolecule deactivation, is crucial for molecular recognition of target molecules or cells. The current available protocols require multiple steps which can lead to low probe stability, specificity, and reproducibility. Here we report a simple and rapid protein bioconjugation method based on a one-step ligand exchange using the DNAs as the linker. Our method benefits from the robust DNA-protein conjugates as well as from multiple ions binding capability. Protein can be preconjugated via an amino group at the 3' end of a synthetic DNA molecule, so that the 5' end phosphoric acid group and multiple phosphate oxygen atoms in the phosphodiester bonds are exposed to replace the oleic acid ligands on the surface of upconversion nanoparticles due to their stronger chelating capability to lanthanides. We demonstrated that our method can efficiently pull out the upconversion nanoparticles from organic solvent into an aqueous phase. The upconversion nanoparticles then become hydrophilic, stable, and specific biomolecules recognition. This allows us to successfully functionalize the upconversion nanoparticles with horseradish peroxidise (HRP) for catalytic colorimetric assay and for streptavidin (SA)-biotin immunoassays.

  9. Synthetic strategies for efficient conjugation of organometallic complexes with pendant protein reactive markers

    KAUST Repository

    Jantke, Dominik

    2013-11-01

    Site-directed conjugation of metal centers to proteins is fundamental for biological and bioinorganic applications of transition metals. However, methods for the site-selective introduction of metal centers remain scarce. Herein, we present broadly applicable synthetic strategies for the conjugation of bioactive molecules with a range of organometallic complexes. Following three different synthetic strategies, we were able to synthesize a small library of metal conjugated protein markers featuring different types of protein reactive sites (epoxides, phenylphosphonates, fluorosulfonates and fluorophosphonate groups) as well as different late transition metals (iron, ruthenium, rhodium, palladium and platinum). The products were isolated in moderate to excellent yields and high purity. Furthermore, X-ray diffraction of the metalated protein markers corroborates structural integrity of the metal complex and the protein reactive site. © 2013 Elsevier B.V. All rights reserved.

  10. Synthetic strategies for efficient conjugation of organometallic complexes with pendant protein reactive markers

    KAUST Repository

    Jantke, Dominik; Marziale, Alexander N.; Reiner, Thomas; Kraus, Florian; Herdtweck, Eberhardt; Raba, Andreas; Eppinger, Jö rg

    2013-01-01

    Site-directed conjugation of metal centers to proteins is fundamental for biological and bioinorganic applications of transition metals. However, methods for the site-selective introduction of metal centers remain scarce. Herein, we present broadly applicable synthetic strategies for the conjugation of bioactive molecules with a range of organometallic complexes. Following three different synthetic strategies, we were able to synthesize a small library of metal conjugated protein markers featuring different types of protein reactive sites (epoxides, phenylphosphonates, fluorosulfonates and fluorophosphonate groups) as well as different late transition metals (iron, ruthenium, rhodium, palladium and platinum). The products were isolated in moderate to excellent yields and high purity. Furthermore, X-ray diffraction of the metalated protein markers corroborates structural integrity of the metal complex and the protein reactive site. © 2013 Elsevier B.V. All rights reserved.

  11. The studies on the preparation of hapten conjugates for extension of the applicability of radioligandassay

    International Nuclear Information System (INIS)

    Kim, J.

    1979-01-01

    The stability of T 4 - 125 I has been secured by addition of a small amount of cysteine in the T 4 - 125 I solution. Various methods for the preparation of thyroid hormone-BSA conjugates were reviewed and an efficient preparation method as well as a qualitative and quantitative analysis procedures for the conjugates has been established. The results of analysis of the prepared hapten conjugates indicated that the mole ratios of BSA: T 3 (acid form) and BSA: T 4 (ethyl ester form) are 1:12 and 1:10, respectively, and the binding % of T 3 (acid form) and T 4 (ethyl ester form) to BSA molecule are 25% and 20%, respectively. (author)

  12. Probing Conformational Change of Bovine Serum Albumin–Dextran Conjugates under Controlled Dry Heating

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Shuqin; Li, Yunqi; Zhao, Qin; Li, Ji; Xia, Qiuyang; Zhang, Xiaoming; Huang, Qingrong (Rutgers); (Chinese Aca. Sci.); (Jiangnan)

    2015-04-29

    The time-dependent conformational change of bovine serum album (BSA) during Maillard reaction with dextran under controlled dry heating has been studied by small-angle X-ray scattering, fluorescence spectroscopy, dynamic light scattering, and circular dichroism analysis. Through the research on the radii of gyration (Rg), intrinsic fluorescence, and secondary structure, conjugates with dextran coating were found to inhibit BSA aggregation and preserve the secondary structure of native BSA against long-time heat treatment during Maillard reaction. The results suggested that the hydrophilic dextran was conjugated to the compact protein surface and enclosed it and more dextran chains were attached to BSA with the increase of the heating time. The study presented here will be beneficial to the understanding of the conformational evolution of BSA molecules during the dry-heating Maillard reaction and to the control of the protein–polysaccharide conjugate structure.

  13. Preconditioning the modified conjugate gradient method ...

    African Journals Online (AJOL)

    In this paper, the convergence analysis of the conventional conjugate Gradient method was reviewed. And the convergence analysis of the modified conjugate Gradient method was analysed with our extension on preconditioning the algorithm. Convergence of the algorithm is a function of the condition number of M-1A.

  14. 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...

  15. Tetrafullerene conjugates for all-organic photovoltaics

    NARCIS (Netherlands)

    Fernández, G.; Sánchez, L.; Veldman, D.; Wienk, M.M.; Atienza, C.M.; Guldi, D.M.; Janssen, R.A.J.; Martin, N.

    2008-01-01

    The synthesis of two new tetrafullerene nanoconjugates in which four C60 units are covalently connected through different -conjugated oligomers (oligo(p-phenylene ethynylene) and oligo(p-phenylene vinylene)) is described. The photovoltaic (PV) response of these C60-based conjugates was evaluated by

  16. CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

    NARCIS (Netherlands)

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

    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. 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)

  18. 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...

  19. Class, Kinship Density, and Conjugal Role Segregation.

    Science.gov (United States)

    Hill, Malcolm D.

    1988-01-01

    Studied conjugal role segregation in 150 married women from intact families in working-class community. Found that, although involvement in dense kinship networks was associated with conjugal role segregation, respondents' attitudes toward marital roles and phase of family cycle when young children were present were more powerful predictors of…

  20. In situ growth of SnO2 nanoparticles in heteroatoms doped cross-linked carbon frameworks for lithium ion batteries anodes

    International Nuclear Information System (INIS)

    Zhou, Xiangyang; Xi, Lihua; Chen, Feng; Bai, Tao; Wang, Biao; Yang, Juan

    2016-01-01

    Highlights: • A facile hydrothermal method is proposed to prepare cross-linked NSG/CNTs@SnO 2 . • The graphene/CNTs anchored with untrasmall SnO 2 nanoparticles can be obtained. • The N, S are successfully incorporated into the carbon matrix. • The NSG/CNTs@SnO 2 presents enhanced cycling stability and good high-rate capacity. - Abstract: SnO 2 -based nanostructures have attracted considerable interest as a promising high-capacity anode materials for lithium ion batteries. We present herein a facile one step hydrothermal approach for in situ growth of SnO 2 nanoparticles in heteroatoms doped cross-linked carbon framework (NSG/CNTs@SnO 2 ). Thiourea is employed as a single source of nitrogen and sulfur in the cross-linked carbon framework (NSG/CNTs). Characterization shows that the SnO 2 nanoparticles with an average size of 6–10 nm are uniformly anchored on NSG/CNTs matrix. When evaluated for the electrochemical properties in lithium ion batteries, the obtained NSG/CNTs@SnO 2 composite with ultrasmall SnO 2 particle size (6–10 nm) delivers a high reversible capacity of 999 mAh g −1 at 200 mA g −1 after 120 cycles and excellent rate performance. Such outstanding electrochemical performance of the peculiar cross-linked NSG/CNTs@SnO 2 composite can be primarily attributed to the synergistic effect of the ultrasmall anchored SnO 2 nanoparticles and the dual-doped NSG/CNTs matrix. The uniformly distributed SnO 2 nanoparticles can deliver large capacity and the robust dual-doped NSG/CNTs matrix can guarantee the good structural integrity and high electrical conductivity during cycling. Besides, the porous structure can provide free space for the volume expansion of SnO 2 and accommodate the strain formed during repeated lithiation/delithiation processes.

  1. Photoelectron Imaging Spectroscopy as a Window to Unexpected Molecules

    Science.gov (United States)

    Blackstone, Christopher C.

    2017-06-01

    Targeting an anion with the formula CH_{3}O_{3} for exploration with photoelectron imaging spectroscopy, we determine its identity to be dihydroxymethanolate, an anion largely absent in the literature, and the conjugate base of the hypothetical species orthoformic acid. Comparing the observed photoelectron spectrum to CCSD-EOM-IP and CCSD-EOM-SF calculations completed in QChem and Franck-Condon overlap simulations in PESCAL, we are able to determine with confidence the connectivity of the atoms in this molecule.

  2. Misonidazole-glutathione conjugates in CHO cells

    International Nuclear Information System (INIS)

    Varghese, A.J.; Whitmore, G.F.

    1984-01-01

    Misonidazole, after reduction to the hydroxylamine derivative, reacts with glutathione (GSH) under physiological conditions. The reaction product has been identified as a mixture of two isomeric conjugates. When water soluble extracts of CHO cells exposed to misonidazole under hypoxic conditions are subjected to HPLC analysis, misonidazole derivatives, having the same chromatographic properties as the GSH-MISO conjugates, were detected. When CHO cells were incubated with misonidazole in the presence of added GSH, a substantial increase in the amount of the conjugate was detected. When extracts of CHO cells exposed to misonidazole under hypoxia were subsequently exposed to GSH, an increased formation of the conjugate was observed. A rearrangement product of the hydroxylamine derivative of misonidazole is postulated as the reactive intermediate responsible for the formation of the conjugate

  3. Approximate error conjugation gradient minimization methods

    Science.gov (United States)

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  4. 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......Conjugation is an important mechanism involved in the transfer of resistance between bacteria. In this article a stochastic differential equation based model consisting of a continuous time state equation and a discrete time measurement equation is introduced to model growth and conjugation of two...... 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...

  5. On the trends of Fukui potential and hardness potential derivatives in isolated atoms vs. atoms in molecules.

    Science.gov (United States)

    Bhattacharjee, Rituparna; Roy, Ram Kinkar

    2014-10-28

    In the present study, trends of electronic contribution to molecular electrostatic potential [Vel(r¯)(r=0)], Fukui potential [v(+)f|(r=0) and v(-)f|(r=0)] and hardness potential derivatives [Δ(+)h(k) and Δ(-)h(k)] for isolated atoms as well as atoms in molecules are investigated. The generated numerical values of these three reactivity descriptors in these two electronically different situations are critically analyzed through the relevant formalism. Values of Vel(r¯) (when r → 0, i.e., on the nucleus) are higher for atoms in molecules than that of isolated atoms. In contrast, higher values of v(+)|(r=0) and v(-)|(r=0) are observed for isolated atoms compared to the values for atoms in a molecule. However, no such regular trend is observed for the Δ(+)h(k) and Δ(-)h(k) values, which is attributed to the uncertainty in the Fukui function values of atoms in molecules. The sum of Fukui potential and the sum of hardness potential derivatives in molecules are also critically analyzed, which shows the efficacy of orbital relaxation effects in quantifying the values of these parameters. The chemical consequence of the observed trends of these descriptors in interpreting electron delocalization, electronic relaxation and non-negativity of atomic Fukui function indices is also touched upon. Several commonly used molecules containing carbon as well as heteroatoms are chosen to make the investigation more insightful.

  6. 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

    Conjugation to cationic cell penetrating peptides (such as Tat, Penetratin, or oligo arginines) efficiently improves the cellular uptake of large hydrophilic molecules such as oligonucleotides and peptide nucleic acids, but the cellular uptake is predominantly via an unproductive endosomal pathway...... 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...... with increasing length of the fatty acid (C8-C16) but in parallel also results in increased cellular toxicity, with decanoic acid being optimal. Furthermore, the relative enhancement is significantly higher for Tat peptide compared to oligoarginine. Confocal microscopy and chloroquine enhancement indicates...

  7. Formation of Ultracold Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cote, Robin [Univ. of Connecticut, Storrs, CT (United States)

    2016-01-28

    Advances in our ability to slow down and cool atoms and molecules to ultracold temperatures have paved the way to a revolution in basic research on molecules. Ultracold molecules are sensitive of very weak interactions, even when separated by large distances, which allow studies of the effect of those interactions on the behavior of molecules. In this program, we have explored ways to form ultracold molecules starting from pairs of atoms that have already reached the ultracold regime. We devised methods that enhance the efficiency of ultracold molecule production, for example by tuning external magnetic fields and using appropriate laser excitations. We also investigates the properties of those ultracold molecules, especially their de-excitation into stable molecules. We studied the possibility of creating new classes of ultra-long range molecules, named macrodimers, thousand times more extended than regular molecules. Again, such objects are possible because ultra low temperatures prevent their breakup by collision. Finally, we carried out calculations on how chemical reactions are affected and modified at ultracold temperatures. Normally, reactions become less effective as the temperature decreases, but at ultracold temperatures, they can become very effective. We studied this counter-intuitive behavior for benchmark chemical reactions involving molecular hydrogen.

  8. Antibody-dendrimer conjugates: the number, not the size of the dendrimers, determines the immunoreactivity.

    Science.gov (United States)

    Wängler, C; Moldenhauer, G; Eisenhut, M; Haberkorn, U; Mier, W

    2008-04-01

    Radioimmunotherapy using antibodies with favorable tumor targeting properties and high binding affinity is increasingly applied in cancer therapy. The potential of this valuable cancer treatment modality could be further improved by increasing the specific activity of the labeled proteins. This can be done either by coupling a large number of chelators which leads to a decreased immunoreactivity or by conjugating a small number of multimeric chelators. In order to systematically investigate the influence of conjugations on immunoreactivity with respect to size and number of the conjugates, the anti-EGFR antibody hMAb425 was reacted with PAMAM dendrimers of different size containing up to 128 chelating agents per conjugation site. An improved dendrimer synthesis protocol was established to obtain compounds of high homogeneity suitable for the formation of defined protein conjugates. The quantitative derivatization of the PAMAM dendrimers with DOTA moieties and the characterization of the products by isotopic dilution titration using (111)In/(nat)In are shown. The DOTA-containing dendrimers were conjugated with high efficiency to hMAb425 by applying Sulfo-SMCC as cross-linking agent and a 10- to 25-fold excess of the thiol-containing dendrimers. The determination of the immunoreactivities of the antibody-dendrimer conjugates by FACS analysis revealed a median retained immunoreactivity of 62.3% for 1.7 derivatization sites per antibody molecule, 55.4% for 2.8, 27.9% for 5.3, and 17.1% for 10.0 derivatization sites per antibody but no significant differences in immunoreactivity for different dendrimer sizes. These results show that the dendrimer size does not influence the immunoreactivity of the derivatized antibody significantly over a wide molecular weight range, whereas the number of derivatization sites has a crucial effect.

  9. Surface functionalization of aluminosilicate nanotubes with organic molecules

    Directory of Open Access Journals (Sweden)

    Wei Ma

    2012-02-01

    Full Text Available The surface functionalization of inorganic nanostructures is an effective approach for enriching the potential applications of existing nanomaterials. Inorganic nanotubes attract great research interest due to their one-dimensional structure and reactive surfaces. In this review paper, recent developments in surface functionalization of an aluminosilicate nanotube, “imogolite”, are introduced. The functionalization processes are based on the robust affinity between phosphate groups of organic molecules and the aluminol (AlOH surface of imogolite nanotubes. An aqueous modification process employing a water soluble ammonium salt of alkyl phosphate led to chemisorption of molecules on imogolite at the nanotube level. Polymer-chain-grafted imogolite nanotubes were prepared through surface-initiated polymerization. In addition, the assembly of conjugated molecules, 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid (HT3P and 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid 1,1-dioxide (HT3OP, on the imogolite nanotube surface was achieved by introducing a phosphonic acid group to the corresponding molecules. The optical and photophysical properties of these conjugated-molecule-decorated imogolite nanotubes were characterized. Moreover, poly(3-hexylthiophene (P3HT chains were further hybridized with HT3P modified imogolite to form a nanofiber hybrid.

  10. The status of molecules

    International Nuclear Information System (INIS)

    Barnes, T.; Oak Ridge National Lab., TN; Tennessee Univ., Knoxville, TN

    1994-06-01

    This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 → 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f o (1710)) which are not well established as molecules but satisfy some of the expected signatures. (Author)

  11. Lactoferrin conjugated iron oxide nanoparticles for targeting brain glioma cells in magnetic particle imaging

    Science.gov (United States)

    Tomitaka, Asahi; Arami, Hamed; Gandhi, Sonu; Krishnan, Kannan M.

    2015-10-01

    Magnetic Particle Imaging (MPI) is a new real-time imaging modality, which promises high tracer mass sensitivity and spatial resolution directly generated from iron oxide nanoparticles. In this study, monodisperse iron oxide nanoparticles with median core diameters ranging from 14 to 26 nm were synthesized and their surface was conjugated with lactoferrin to convert them into brain glioma targeting agents. The conjugation was confirmed with the increase of the hydrodynamic diameters, change of zeta potential, and Bradford assay. Magnetic particle spectrometry (MPS), performed to evaluate the MPI performance of these nanoparticles, showed no change in signal after lactoferrin conjugation to nanoparticles for all core diameters, suggesting that the MPI signal is dominated by Néel relaxation and thus independent of hydrodynamic size difference or presence of coating molecules before and after conjugations. For this range of core sizes (14-26 nm), both MPS signal intensity and spatial resolution improved with increasing core diameter of nanoparticles. The lactoferrin conjugated iron oxide nanoparticles (Lf-IONPs) showed specific cellular internalization into C6 cells with a 5-fold increase in MPS signal compared to IONPs without lactoferrin, both after 24 h incubation. These results suggest that Lf-IONPs can be used as tracers for targeted brain glioma imaging using MPI.

  12. Effect of Maillard Conjugates on the Physical Stability of Zein Nanoparticles Prepared by Liquid Antisolvent Coprecipitation.

    Science.gov (United States)

    Davidov-Pardo, Gabriel; Joye, Iris J; Espinal-Ruiz, Mauricio; McClements, David Julian

    2015-09-30

    Protein nanoparticles are often not very stable in a complex food matrix because they are primarily stabilized by electrostatic repulsion. In this study, we envisaged the stabilization of zein nanoparticles through Maillard conjugation reactions with polysaccharides of different molecular mass. Zein nanoparticles (0.5% w/v) containing resveratrol (0.025% w/v grape skin extract) were produced by liquid antisolvent precipitation and coated with Maillard conjugates (MC) of sodium caseinate and different molecular mass carbohydrates during particle production. Zein nanoparticles coated with conjugated polysaccharides of 2.8, 37, and 150 kDa had diameters of 198 ± 5, 176 ± 6, and 180 ± 3 nm, respectively. The encapsulation efficiency (∼83%) was not affected by conjugation, but the conjugates significantly improved particle stability against changes in pH (2.0-9.0), CaCl2 addition (up to 100 mM), and heat treatment (30-90 °C, 30 min). Zein nanoparticles coated by MC may therefore be suitable delivery systems for hydrophobic bioactive molecules in a wide range of commercial products.

  13. Nanostructured Conjugated Polymers for Energy-Related Applications beyond Solar Cells.

    Science.gov (United States)

    Xie, Jian; Zhao, Cui-E; Lin, Zong-Qiong; Gu, Pei-Yang; Zhang, Qichun

    2016-05-20

    To meet the ever-increasing requirements for the next generation of sustainable and versatile energy-related devices, conjugated polymers, which have potential advantages over small molecules and inorganic materials, are among the most promising types of green candidates. The properties of conjugated polymers can be tuned through modification of the structure and incorporation of different functional moieties. In addition, superior performances can be achieved as a result of the advantages of nanostructures, such as their large surface areas and the shortened pathways for charge transfer. Therefore, nanostructured conjugated polymers with different properties can be obtained to be applied in different energy-related organic devices. This review focuses on the application and performance of the recently reported nanostructured conjugated polymers for high-performance devices, including rechargeable lithium batteries, microbial fuel cells (MFCs), thermoelectric generators, and photocatalytic systems. The design strategies, reaction mechanisms, advantages, and limitations of nanostructured conjugated polymers are further discussed in each section. Finally, possible routes to improve the performances of the current systems are also included in the conclusion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Photoinduced electron transfer in a Watson-Crick base-paired, 2-aminopurine:uracil-C60 hydrogen bonding conjugate.

    Science.gov (United States)

    D'Souza, Francis; Gadde, Suresh; Islam, D-M Shafiqul; Pang, Siew-Cheng; Schumacher, Amy Lea; Zandler, Melvin E; Horie, Rumiko; Araki, Yasuyaki; Ito, Osamu

    2007-02-07

    A fluorescent reporter molecule, 2-aminopurine was self-assembled via Watson-Crick base-pairing to a uracil appended fullerene to form a donor-acceptor conjugate; efficient photoinduced charge separation was confirmed by time-resolved emission and transient absorption spectral studies.

  15. Cold Rydberg molecules

    Science.gov (United States)

    Raithel, Georg; Zhao, Jianming

    2017-04-01

    Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

  16. Indication of viruses and virus-specific antibodies by ELISA using conjugates based on β-lactamase obtained by genetic engineering

    International Nuclear Information System (INIS)

    Kharitonenkov, I.G.; Kordym, V.A.; Khristova, M.L.; Leonov, S.V.; Kirillova, V.S.; Chernykh, S.I.

    1987-01-01

    The method of enzyme-linked immunosorbent assay (ELISA), by means of which antigens and antibodies of different origin can be detected with high sensitivity and specificity, is an immunoenzymatic technique based on the use of conjugates, or macromolecular complexes formed by covalent attachment of enzyme molecules to antigen or antibody molecules. Conjugates based on peroxidase, alkaline phosphatase, and beta-galactosidase are most frequently used to construct immunoenzymatic test systems. The use of these enzymes in ELISA, however, is complicated by the fact that they are often present in free or bound form in the biological material under study, and that their substrates either possess low stability, are difficult to synthesize, or are toxic. In this paper, in order to avoid these shortcomings, the authors develop a method for the biosynthesis of lactamase conjugates which is based on genetic engineering, and demonstrate the viability and stability of these conjugates in radioimmunoenzymatic assay of viruses

  17. Computational and Experimental Insight Into Single-Molecule Piezoelectric Materials

    Science.gov (United States)

    Marvin, Christopher Wayne

    Piezoelectric materials allow for the harvesting of ambient waste energy from the environment. Producing lightweight, highly responsive materials is a challenge for this type of material, requiring polymer, foam, or bio-inspired materials. In this dissertation, I explore the origin of the piezoelectric effect in single molecules through density functional theory (DFT), analyze the piezoresponse of bio-inspired peptidic materials through the use of atomic and piezoresponse force microscopy (AFM and PFM), and develop a novel class of materials combining flexible polyurethane foams and non-piezoelectric, polar dopants. For the DFT calculations, functional group, regiochemical, and heteroatom derivatives of [6]helicene were examined for their influence on the piezoelectric response. An aza[6]helicene derivative was found to have a piezoelectric response (108 pm/V) comparable to ceramics such as lead zirconium titanate (200+ pm/V). These computed materials have the possibility to compete with current field-leading piezomaterials such as lead zirconium titanate (PZT), zinc oxide (ZnO), and polyvinylidene difluoride (PVDF) and its derivatives. The use of AFM/PFM allows for the demonstration of the piezoelectric effect of the selfassembled monolayer (SAM) peptidic systems. Through PFM, the influence that the helicity and sequence of the peptide has on the overall response of the molecule can be analyzed. Finally, development of a novel class of piezoelectrics, the foam-based materials, expands the current understanding of the qualities required for a piezoelectric material from ceramic and rigid materials to more flexible, organic materials. Through the exploration of these novel types of piezoelectric materials, new design rules and figures of merit have been developed.

  18. Coupling of dextrans conjugated with boron to γ globulin: a model for NCT

    International Nuclear Information System (INIS)

    Elmore, J.J. Jr.; Borg, D.C.; Micca, P.; Gabel, D.

    1982-01-01

    To achieve the selective localization of boron in or on cancer cells or other target cells, the authors have elected to use water-soluble dextrans as intermediate carriers. This permits each MCA molecule to target many atoms of boron-10 to the specified antigenic receptors while only 5 to 10 of the amino acid residues of the protein are conjugated by dextrans carrying boron-10. As a result, there should be little of the loss of receptor specificity or affinity

  19. Fluorophore-conjugated iron oxide nanoparticle labeling and analysis of engrafting human hematopoietic stem cells

    DEFF Research Database (Denmark)

    Maxwell, Dustin J; Bonde, Jesper; Hess, David A

    2008-01-01

    culture conditions to maintain viability without inducing terminal differentiation. In the current study, fluorescent molecules were covalently linked to dextran-coated iron oxide nanoparticles (Feridex) to characterize human HSC labeling to monitor the engraftment process. Conjugating fluorophores...... to the dextran coat for fluorescence-activated cell sorting purification eliminated spurious signals from nonsequestered nanoparticle contaminants. A short-term defined incubation strategy was developed that allowed efficient labeling of both quiescent and cycling HSC, with no discernable toxicity in vitro...

  20. Novel Aflatoxin Derivatives and Protein Conjugates

    Directory of Open Access Journals (Sweden)

    Reinhard Niessner

    2007-03-01

    Full Text Available Aflatoxins, a group of structurally related mycotoxins, are well known for their toxic and carcinogenic effects in humans and animals. Aflatoxin derivatives and protein conjugates are needed for diverse analytical applications. This work describes a reliable and fast synthesis of novel aflatoxin derivatives, purification by preparative HPLC and characterisation by ESI-MS and one- and two-dimensional NMR. Novel aflatoxin bovine serum albumin conjugates were prepared and characterised by UV absorption and MALDI-MS. These aflatoxin protein conjugates are potentially interesting as immunogens for the generation of aflatoxin selective antibodies with novel specificities.

  1. Multifunctional adhesive polymers: Preactivated thiolated chitosan-EDTA conjugates.

    Science.gov (United States)

    Netsomboon, Kesinee; Suchaoin, Wongsakorn; Laffleur, Flavia; Prüfert, Felix; Bernkop-Schnürch, Andreas

    2017-02-01

    The aim of this study was to synthesis preactivated thiolated chitosan-EDTA (Ch-EDTA-cys-2MNA) conjugates exhibiting in particular high mucoadhesive, cohesive and chelating properties. Thiol groups were coupled with chitosan by carbodiimide reaction and further preactivated by attachment with 2-mercaptonicotinic acid (2MNA) via disulfide bond formation. Determinations of primary amino and sulfhydryl groups were performed by TNBS and Ellman's tests, respectively. Cytotoxicity was screened by resazurin assay in Caco-2 cells. Mucoadhesive properties and bivalent cation binding capacity with Mg 2+ and Ca 2+ in comparison to chitosan-EDTA (Ch-EDTA) and thiolated Ch-EDTA (Ch-EDTA-cys) were evaluated. Determination of 2MNA and total sulfhydryl groups indicated that 80% of thiol groups were preactivated. The results from cytotoxicity studies demonstrated that Ch-EDTA-cys and Ch-EDTA-cys-2MNA were not toxic to the cells at the polymer test concentration of 0.25% (w/v) while cell viability decreased by increasing the concentration of Ch-EDTA. Although EDTA molecule was modified by thiolation and preactivation, approximately 50% of chelating properties of the conjugates were maintained compared to Ch-EDTA. Ch-EDTA-cys-2MNA adhered on freshly excised porcine intestinal mucosa up to 6h while Ch-EDTA adhered for just 1h. According to the combination of mucoadhesive and chelating properties of the conjugates synthesized in this study, Ch-EDTA-cys-2MNA might be useful for various mucosal drug delivery systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. A rapid approach for characterization of thiol-conjugated antibody-drug conjugates and calculation of drug-antibody ratio by liquid chromatography mass spectrometry.

    Science.gov (United States)

    Firth, David; Bell, Leonard; Squires, Martin; Estdale, Sian; McKee, Colin

    2015-09-15

    We present the demonstration of a rapid "middle-up" liquid chromatography mass spectrometry (LC-MS)-based workflow for use in the characterization of thiol-conjugated maleimidocaproyl-monomethyl auristatin F (mcMMAF) and valine-citrulline-monomethyl auristatin E (vcMMAE) antibody-drug conjugates. Deconvoluted spectra were generated following a combination of deglycosylation, IdeS (immunoglobulin-degrading enzyme from Streptococcus pyogenes) digestion, and reduction steps that provide a visual representation of the product for rapid lot-to-lot comparison-a means to quickly assess the integrity of the antibody structure and the applied conjugation chemistry by mass. The relative abundance of the detected ions also offer information regarding differences in drug conjugation levels between samples, and the average drug-antibody ratio can be calculated. The approach requires little material (<100 μg) and, thus, is amenable to small-scale process development testing or as an early component of a complete characterization project facilitating informed decision making regarding which aspects of a molecule might need to be examined in more detail by orthogonal methodologies. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Highly parallel translation of DNA sequences into small molecules.

    Directory of Open Access Journals (Sweden)

    Rebecca M Weisinger

    Full Text Available A large body of in vitro evolution work establishes the utility of biopolymer libraries comprising 10(10 to 10(15 distinct molecules for the discovery of nanomolar-affinity ligands to proteins. Small-molecule libraries of comparable complexity will likely provide nanomolar-affinity small-molecule ligands. Unlike biopolymers, small molecules can offer the advantages of cell permeability, low immunogenicity, metabolic stability, rapid diffusion and inexpensive mass production. It is thought that such desirable in vivo behavior is correlated with the physical properties of small molecules, specifically a limited number of hydrogen bond donors and acceptors, a defined range of hydrophobicity, and most importantly, molecular weights less than 500 Daltons. Creating a collection of 10(10 to 10(15 small molecules that meet these criteria requires the use of hundreds to thousands of diversity elements per step in a combinatorial synthesis of three to five steps. With this goal in mind, we have reported a set of mesofluidic devices that enable DNA-programmed combinatorial chemistry in a highly parallel 384-well plate format. Here, we demonstrate that these devices can translate DNA genes encoding 384 diversity elements per coding position into corresponding small-molecule gene products. This robust and efficient procedure yields small molecule-DNA conjugates suitable for in vitro evolution experiments.

  4. Role of isothiocyanate conjugate of pterostilbene on the inhibition of MCF-7 cell proliferation and tumor growth in Ehrlich ascitic cell induced tumor bearing mice

    Energy Technology Data Exchange (ETDEWEB)

    Nikhil, Kumar; Sharan, Shruti; Chakraborty, Ajanta [Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India); Bodipati, Naganjaneyulu; Krishna Peddinti, Rama [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India); Roy, Partha, E-mail: paroyfbs@iitr.ernet.in [Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247 667, Uttarakhand (India)

    2014-01-15

    Naturally occurring pterostilbene (PTER) and isothiocyanate (ITC) attract great attention due to their wide range of biological properties, including anti-cancer, anti-leukemic, anti-bacterial and anti-inflammatory activities. A novel class of hybrid compound synthesized by introducing an ITC moiety on PTER backbone was evaluated for its anti-cancer efficacy in hormone-dependent breast cancer cell line (MCF-7) in vitro and Ehrlich ascitic tumor bearing mice model in vivo. The novel hybrid molecule showed significant in vitro anti-cancer activity (IC{sub 50}=25±0.38) when compared to reference compound PTER (IC{sub 50}=65±0.42). The conjugate molecule induced both S and G2/M phase cell cycle arrest as indicated by flow cytometry analysis. In addition, the conjugate induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-9, release of cytochrome-c into cytosol and increased Bax: Bcl-2 ratio. The conjugate also suppressed the phosphorylation of Akt and ERK. The conjugate induced cell death was significantly increased in presence of A6730 (a potent Akt1/2 kinase inhibitor) and PD98059 (a specific ERK inhibitor). Moreover, the conjugated PTER inhibited tumor growth in Ehrlich ascitic cell induced tumor bearing mice as observed by reduction in tumor volume compared to untreated animals. Collectively, the pro-apoptotic effect of conjugate is mediated through the activation of caspases, and is correlated with the blockade of the Akt and ERK signaling pathways in MCF-7 cells. - Highlights: • Conjugate was prepared by appending isothiocyanate moiety on pterostilbene backbone. • Conjugate showed anticancer effects at comparatively lower dose than pterostilbene. • Conjugate caused blockage of the Akt and ERK signaling pathways in MCF-7 cells. • Conjugate significantly reduced solid tumor volume as compared to pterostilbene.

  5. Role of isothiocyanate conjugate of pterostilbene on the inhibition of MCF-7 cell proliferation and tumor growth in Ehrlich ascitic cell induced tumor bearing mice

    International Nuclear Information System (INIS)

    Nikhil, Kumar; Sharan, Shruti; Chakraborty, Ajanta; Bodipati, Naganjaneyulu; Krishna Peddinti, Rama; Roy, Partha

    2014-01-01

    Naturally occurring pterostilbene (PTER) and isothiocyanate (ITC) attract great attention due to their wide range of biological properties, including anti-cancer, anti-leukemic, anti-bacterial and anti-inflammatory activities. A novel class of hybrid compound synthesized by introducing an ITC moiety on PTER backbone was evaluated for its anti-cancer efficacy in hormone-dependent breast cancer cell line (MCF-7) in vitro and Ehrlich ascitic tumor bearing mice model in vivo. The novel hybrid molecule showed significant in vitro anti-cancer activity (IC 50 =25±0.38) when compared to reference compound PTER (IC 50 =65±0.42). The conjugate molecule induced both S and G2/M phase cell cycle arrest as indicated by flow cytometry analysis. In addition, the conjugate induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-9, release of cytochrome-c into cytosol and increased Bax: Bcl-2 ratio. The conjugate also suppressed the phosphorylation of Akt and ERK. The conjugate induced cell death was significantly increased in presence of A6730 (a potent Akt1/2 kinase inhibitor) and PD98059 (a specific ERK inhibitor). Moreover, the conjugated PTER inhibited tumor growth in Ehrlich ascitic cell induced tumor bearing mice as observed by reduction in tumor volume compared to untreated animals. Collectively, the pro-apoptotic effect of conjugate is mediated through the activation of caspases, and is correlated with the blockade of the Akt and ERK signaling pathways in MCF-7 cells. - Highlights: • Conjugate was prepared by appending isothiocyanate moiety on pterostilbene backbone. • Conjugate showed anticancer effects at comparatively lower dose than pterostilbene. • Conjugate caused blockage of the Akt and ERK signaling pathways in MCF-7 cells. • Conjugate significantly reduced solid tumor volume as compared to pterostilbene

  6. Molecule of the Month

    Indian Academy of Sciences (India)

    Atoms in a molecule generally prefer, particularly among the neighbouring ones, certain optimmn geometrical relationships. These are manifested in specific ranges of bond lengths, bond angles, torsion angles etc. As it always happens, chemists are interested in making molecules where these 'standard relationships' are ...

  7. Molecule of the Month

    Indian Academy of Sciences (India)

    Cyclo bu tadiene (1) has been one of the most popular molecules for experimentalists and theoreticians. This molecule is unstable as . it is antiaromatic ( 4,n electrons in a cyclic array). Even though some highly substituted cyclobutadienes, for example, compound 2 and the Fe(CO)3 complex of cyclobutadiene (3) are ...

  8. Single-Molecule Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Single-Molecule Spectroscopy: Every Molecule is Different! Kankan Bhattacharyya. General Article Volume 20 Issue 2 February 2015 pp 151-164. Fulltext. Click here to view fulltext PDF. Permanent link:

  9. Single molecule conductance

    NARCIS (Netherlands)

    Willems, R.

    2008-01-01

    This thesis represents an excursion into the world of molecular electronics, i.e. the field of research trying to use individual (organic) molecules as electronic components; in this work various experimental methods have been explored to connect individual molecules to metallic contacts and

  10. Molecules in stars

    International Nuclear Information System (INIS)

    Tsuji, T.

    1986-01-01

    Recently, research related to molecules in stars has rapidly expanded because of progress in related fields. For this reason, it is almost impossible to cover all the topics related to molecules in stars. Thus, here the authors focus their attention on molecules in the atmospheres of cool stars and do not cover in any detail topics related to circumstellar molecules originating from expanding envelopes located far from the stellar surface. However, the authors do discuss molecules in quasi-static circumstellar envelopes (a recently discovered new component of circumstellar envelopes) located near the stellar surface, since molecular lines originating from such envelopes show little velocity shift relative to photospheric lines, and hence they directly affect the interpretation and analysis of stellar spectra

  11. X-ray induced singlet oxygen generation by nanoparticle-photosensitizer conjugates for photodynamic therapy: determination of singlet oxygen quantum yield

    OpenAIRE

    Clement, Sandhya; Deng, Wei; Camilleri, Elizabeth; Wilson, Brian C.; Goldys, Ewa M.

    2016-01-01

    Singlet oxygen is a primary cytotoxic agent in photodynamic therapy. We show that CeF3 nanoparticles, pure as well as conjugated through electrostatic interaction with the photosensitizer verteporfin, are able to generate singlet oxygen as a result of UV light and 8?keV X-ray irradiation. The X-ray stimulated singlet oxygen quantum yield was determined to be 0.79???0.05 for the conjugate with 31 verteporfin molecules per CeF3 nanoparticle, the highest conjugation level used. From this result ...

  12. Dielectrophoresis of gold nanoparticles conjugated to DNA origami structures

    Directory of Open Access Journals (Sweden)

    Anja Henning-Knechtel

    2016-07-01

    Full Text Available DNA nanostructures are promising construction materials to bridge the gap between self-assembly of functional molecules and conventional top-down fabrication methods in nanotechnology. Their positioning onto specific locations of a microstructured substrate is an important task towards this aim. Here we study manipulation and positioning of pristine and of gold nanoparticle-conjugated tubular DNA origami structures using ac dielectrophoresis. The dielectrophoretic behavior was investigated employing fluorescence microscopy. For the pristine origami, a significant dielectrophoretic response was found to take place in the megahertz range, whereas, due to the higher polarizability of the metallic nanoparticles, the nanoparticle/DNA hybrid structures required a lower electrical field strength and frequency for a comparable trapping at the edges of the electrode structure. The nanoparticle conjugation additionally resulted in a remarkable alteration of the DNA structure arrangement. The growth of linear, chain-like structures in between electrodes at applied frequencies in the megahertz range was observed. The long-range chain formation is caused by a local, gold nanoparticle-induced field concentration along the DNA nanostructures, which in turn, creates dielectrophoretic forces that enable the observed self-alignment of the hybrid structures.

  13. Genetic engineering and chemical conjugation of potato virus X.

    Science.gov (United States)

    Lee, Karin L; Uhde-Holzem, Kerstin; Fischer, Rainer; Commandeur, Ulrich; Steinmetz, Nicole F

    2014-01-01

    Here we report the genetic engineering and chemical modification of potato virus X (PVX) for the presentation of various peptides, proteins, and fluorescent dyes, or other chemical modifiers. Three different ways of genetic engineering are described and by these means, peptides are successfully expressed not only when the foot and mouth disease virus (FMDV) 2A sequence or a flexible glycine-serine linker is included, but also when the peptide is fused directly to the PVX coat protein. When larger proteins or unfavorable peptide sequences are presented, a partial fusion via the FMDV 2A sequence is preferable. When these PVX chimeras retain the ability to assemble into viral particles and are thus able to infect plants systemically, they can be utilized to inoculate susceptible plants for isolation of sufficient amounts of virus particles for subsequent chemical modification. Chemical modification is required for the display of nonbiological ligands such as fluorophores, polymers, and small drug compounds. We present three methods of chemical bioconjugation. For direct conjugation of small chemical modifiers to solvent exposed lysines, N-hydroxysuccinimide chemistry can be applied. Bio-orthogonal reactions such as copper-catalyzed azide-alkyne cycloaddition or hydrazone ligation are alternatives to achieve more efficient conjugation (e.g., when working with high molecular weight or insoluble ligands). Furthermore, hydrazone ligation offers an attractive route for the introduction of pH-cleavable cargos (e.g., therapeutic molecules).

  14. Evaluation of iodovinyl antibody conjugates: Comparison with a p-iodobenzoyl conjugate and direct radioiodination

    International Nuclear Information System (INIS)

    Hadley, S.W.; Wilbur, D.S.

    1990-01-01

    The preparations and conjugations of 2,3,5,6-tetrafluorophenyl 5-[125I/131I]iodo-4-pentenoate (7a) and 2,3,5,6-tetrafluorophenyl 3,3-dimethyl-5-[125I/131I]iodo-4-pentenoate (7b) to monoclonal antibodies are reported. Reagents 7a and 7b were prepared in high radiochemical yield by iododestannylation of their corresponding 5-tri-n-butylstannyl precursors. Radioiodinated antibody conjugates were prepared by reaction of 7a or 7b with the protein at basic pH. Evaluation of these conjugates by several in vitro procedures demonstrated that the radiolabel was attached to the antibody in a stable manner and that the conjugates maintained immunoreactivity. Comparative dual-isotope biodistribution studies of a monoclonal antibody Fab fragment conjugate of 7a and 7b with the same Fab fragment labeled with N-succinimidyl p-[131I]iodobenzoate (PIB, p-iodobenzoate, 2) or directly radioiodinated have been carried out in tumor-bearing nude mice. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 2 demonstrated that the biodistributions were similar in most organs, except the neck tissue (thyroid-containing) and the stomach, which contained substantially increased levels of the 7a label. Coinjection of the Fab conjugate of 7a with the Fab fragment radioiodinated by using the chloramine-T method demonstrated that the biodistributions were remarkably similar, suggesting roughly equivalent in vivo deiodination of these labeled antibody fragments. Coinjection of the Fab conjugate of 7a with the Fab conjugate of 7b indicated that there was ∼ a 2-fold reduction in the amount of in vivo deiodination of the 7b conjugate as compared to the 7a conjugate

  15. Influence of thermocleavable functionality on organic field-effect transistor performance of small molecules

    Science.gov (United States)

    Mahale, Rajashree Y.; Dharmapurikar, Satej S.; Chini, Mrinmoy Kumar; Venugopalan, Vijay

    2017-06-01

    Diketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160 °C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07 × 10-5 cm2/V s.

  16. Conjugate descent formulation of backpropagation error in ...

    African Journals Online (AJOL)

    nique of backpropagation was popularized in a paper by Rumelhart, et al. ... the training of a multilayer neural network using a gradient descent approach applied to a .... superior convergence of the conjugate descent method over a standard ...

  17. Factors Affecting the Pharmacology of Antibody–Drug Conjugates

    Directory of Open Access Journals (Sweden)

    Andrew T. Lucas

    2018-02-01

    Full Text Available Major advances in therapeutic proteins, including antibody–drug conjugates (ADCs, have created revolutionary drug delivery systems in cancer over the past decade. While these immunoconjugate agents provide several advantages compared to their small-molecule counterparts, their clinical use is still in its infancy. The considerations in their development and clinical use are complex, and consist of multiple components and variables that can affect the pharmacologic characteristics. It is critical to understand the mechanisms employed by ADCs in navigating biological barriers and how these factors affect their biodistribution, delivery to tumors, efficacy, and toxicity. Thus, future studies are warranted to better understand the complex pharmacology and interaction between ADC carriers and biological systems, such as the mononuclear phagocyte system (MPS and tumor microenvironment. This review provides an overview of factors that affect the pharmacologic profiles of ADC therapies that are currently in clinical use and development.

  18. Soluble polymer conjugates for drug delivery.

    Science.gov (United States)

    Minko, Tamara

    2005-01-01

    The use of water-soluble polymeric conjugates as drug carriers offers several possible advantages. These advantages include: (1) improved drug pharmacokinetics; (2) decreased toxicity to healthy organs; (3) possible facilitation of accumulation and preferential uptake by targeted cells; (4) programmed profile of drug release. In this review, we will consider the main types of useful polymeric conjugates and their role and effectiveness as carriers in drug delivery systems.: © 2005 Elsevier Ltd . All rights reserved.

  19. Diffeomorphisms Holder conjugate to Anosov diffeomorphisms

    OpenAIRE

    Gogolev, Andrey

    2008-01-01

    We show by means of a counterexample that a $C^{1+Lip}$ diffeomorphism Holder conjugate to an Anosov diffeomorphism is not necessarily Anosov. The counterexample can bear higher smoothness up to $C^3$. Also we include a result from the 2006 Ph.D. thesis of T. Fisher: a $C^{1+Lip}$ diffeomorphism Holder conjugate to an Anosov diffeomorphism is Anosov itself provided that Holder exponents of the conjugacy and its inverse are sufficiently large.

  20. Rapid modification of retroviruses using lipid conjugates

    International Nuclear Information System (INIS)

    Mukherjee, Nimisha G; Le Doux, Joseph M; Andrew Lyon, L

    2009-01-01

    Methods are needed to manipulate natural nanoparticles. Viruses are particularly interesting because they can act as therapeutic cellular delivery agents. Here we examine a new method for rapidly modifying retroviruses that uses lipid conjugates composed of a lipid anchor (1,2-distearoyl-sn-glycero-3-phosphoethanolamine), a polyethylene glycol chain, and biotin. The conjugates rapidly and stably modified retroviruses and enabled them to bind streptavidin. The implication of this work for modifying viruses for gene therapy and vaccination protocols is discussed.

  1. Dynamics of Activated Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, Amy S. [Univ. of Maryland, College Park, MD (United States)

    2016-11-16

    Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

  2. Dissociation in small molecules

    International Nuclear Information System (INIS)

    Dehmer, P.M.

    1982-01-01

    The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

  3. Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions.

    Science.gov (United States)

    Xin, Na; Wang, Jinying; Jia, Chuancheng; Liu, Zitong; Zhang, Xisha; Yu, Chenmin; Li, Mingliang; Wang, Shuopei; Gong, Yao; Sun, Hantao; Zhang, Guanxin; Liu, Zhirong; Zhang, Guangyu; Liao, Jianhui; Zhang, Deqing; Guo, Xuefeng

    2017-02-08

    Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.

  4. Application of a small molecule radiopharmaceutical concept to improve kinetics

    International Nuclear Information System (INIS)

    Jeong, Jae Min

    2016-01-01

    Recently, large molecules or nanoparticles are actively studied as radiopharmaceuticals. However, their kinetics is problematic because of a slow penetration through the capillaries and slow distribution to the target. To improve the kinetics, a two-step targeting method can be applied by using small molecules and very rapid copper-free click reaction. Although this method might have limitations such as internalization of the first targeted conjugate, it will provide high target-to-non-target ratio imaging of radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals. In conclusion, the small molecule radiopharmaceuticals generally show excellent biodistribution properties; however, they show poor efficiency of radioisotope delivery. Large molecule or nanoparticle radiopharmaceuticals have advantages of multimodal and efficient delivery, but lower target-to-non-target ratio. Two-step targeting using a bio-orthogonal copper-free click reaction can be a solution of the problem of large molecule or nanoparticle radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals

  5. Application of a small molecule radiopharmaceutical concept to improve kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jae Min [Dept. of Nuclear Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    Recently, large molecules or nanoparticles are actively studied as radiopharmaceuticals. However, their kinetics is problematic because of a slow penetration through the capillaries and slow distribution to the target. To improve the kinetics, a two-step targeting method can be applied by using small molecules and very rapid copper-free click reaction. Although this method might have limitations such as internalization of the first targeted conjugate, it will provide high target-to-non-target ratio imaging of radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals. In conclusion, the small molecule radiopharmaceuticals generally show excellent biodistribution properties; however, they show poor efficiency of radioisotope delivery. Large molecule or nanoparticle radiopharmaceuticals have advantages of multimodal and efficient delivery, but lower target-to-non-target ratio. Two-step targeting using a bio-orthogonal copper-free click reaction can be a solution of the problem of large molecule or nanoparticle radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals.

  6. Distinct uptake mechanisms but similar intracellular processing of two different toll-like receptor ligand-peptide conjugates in dendritic cells.

    Science.gov (United States)

    Khan, Selina; Bijker, Martijn S; Weterings, Jimmy J; Tanke, Hans J; Adema, Gosse J; van Hall, Thorbald; Drijfhout, Jan W; Melief, Cornelis J M; Overkleeft, Hermen S; van der Marel, Gijsbert A; Filippov, Dmitri V; van der Burg, Sjoerd H; Ossendorp, Ferry

    2007-07-20

    Covalent conjugation of Toll-like receptor ligands (TLR-L) to synthetic antigenic peptides strongly improves antigen presentation in vitro and T lymphocyte priming in vivo. These molecularly well defined TLR-L-peptide conjugates, constitute an attractive vaccination modality, sharing the peptide antigen and a defined adjuvant in one single molecule. We have analyzed the intracellular trafficking and processing of two TLR-L conjugates in dendritic cells (DCs). Long synthetic peptides containing an ovalbumin cytotoxic T-cell epitope were chemically conjugated to two different TLR-Ls the TLR2 ligand, Pam(3)CysSK(4) (Pam) or the TLR9 ligand CpG. Rapid and enhanced uptake of both types of TLR-L-conjugated peptide occurred in DCs. Moreover, TLR-L conjugation greatly enhanced antigen presentation, a process that was dependent on endosomal acidification, proteasomal cleavage, and TAP translocation. The uptake of the CpG approximately conjugate was independent of endosomally-expressed TLR9 as reported previously. Unexpectedly, we found that Pam approximately conjugated peptides were likewise internalized independently of the expression of cell surface-expressed TLR2. Further characterization of the uptake mechanisms revealed that TLR2-L employed a different uptake route than TLR9-L. Inhibition of clathrin- or caveolin-dependent endocytosis greatly reduced uptake and antigen presentation of the Pam-conjugate. In contrast, internalization and antigen presentation of CpG approximately conjugates was independent of clathrin-coated pits but partly dependent on caveolae formation. Importantly, in contrast to the TLR-independent uptake of the conjugates, TLR expression and downstream TLR signaling was required for dendritic cell maturation and for priming of naïve CD8(+) T-cells. Together, our data show that targeting to two distinct TLRs requires distinct uptake mechanism but follows similar trafficking and intracellular processing pathways leading to optimal antigen

  7. Single-Molecule Photocurrent at a Metal-Molecule-Semiconductor Junction.

    Science.gov (United States)

    Vezzoli, Andrea; Brooke, Richard J; Higgins, Simon J; Schwarzacher, Walther; Nichols, Richard J

    2017-11-08

    We demonstrate here a new concept for a metal-molecule-semiconductor nanodevice employing Au and GaAs contacts that acts as a photodiode. Current-voltage traces for such junctions are recorded using a STM, and the "blinking" or "I(t)" method is used to record electrical behavior at the single-molecule level in the dark and under illumination, with both low and highly doped GaAs samples and with two different types of molecular bridge: nonconjugated pentanedithiol and the more conjugated 1,4-phenylene(dimethanethiol). Junctions with highly doped GaAs show poor rectification in the dark and a low photocurrent, while junctions with low doped GaAs show particularly high rectification ratios in the dark (>10 3 for a 1.5 V bias potential) and a high photocurrent in reverse bias. In low doped GaAs, the greater thickness of the depletion layer not only reduces the reverse bias leakage current, but also increases the volume that contributes to the photocurrent, an effect amplified by the point contact geometry of the junction. Furthermore, since photogenerated holes tunnel to the metal electrode assisted by the HOMO of the molecular bridge, the choice of the latter has a strong influence on both the steady state and transient metal-molecule-semiconductor photodiode response. The control of junction current via photogenerated charge carriers adds new functionality to single-molecule nanodevices.

  8. In vivo and in vitro toxicity of nanogold conjugated snake venom protein toxin GNP-NKCT1

    Directory of Open Access Journals (Sweden)

    Partha Pratim Saha

    2014-01-01

    Full Text Available Research on nanoparticles has created interest among the biomedical scientists. Nanoparticle conjugation aims to target drug delivery, increase drug efficacy and imaging for better diagnosis. Toxicity profile of the nanoconjugated molecules has not been studied well. In this communication, the toxicity profile of snake venom cytotoxin (NKCT1, an antileukemic protein toxin, was evaluated after its conjugation with gold nanoparticle (GNP-NKCT1. Gold nanoparticle conjugation with NKCT1 was done with NaBH4 reduction method. The conjugated product GNP-NKCT1 was found less toxic than NKCT1 on isolated rat lymphocyte, mice peritoneal macrophage, in culture, which was evident from the MTT/Trypan blue assay. Peritoneal mast cell degranulation was in the order of NKCT1 > GNP-NKCT1. The in vitro cardiotoxicity and neurotoxicity were increased in case of NKCT1 than GNP-NKCT1. On isolated kidney tissue, NKCT1 released significant amount of ALP and γ-GT than GNP-NKCT1. Gold nanoconjugation with NKCT1 also reduced the lethal activity in mice. In vivo acute/sub-chronic toxicity studies in mice showed significant increase in molecular markers due to NKCT1 treatment, which was reduced by gold nanoconjugation. Histopathology study showed decreased toxic effect of NKCT1 in kidney tissue after GNP conjugation. The present study confirmed that GNP conjugation significantly decreased the toxicity profile of NKCT1. Further studies are in progress to establish the molecular mechanism of GNP induced toxicity reduction.

  9. [Optimizing synthesis of conjugates of superoxide dismutase and catalase with aldehyde dextrans in surfactant microemulsions in heptane].

    Science.gov (United States)

    Eremin, A N; Metelitsa, D I

    1997-01-01

    Stable microemulsions in heptane retaining considerable amounts of the polar phase were obtained by using Aerosol OT (AOT), Triton X-45, and catalase. Conjugates of superoxide dismutase (SOD) and catalase with aldehyde dextrans (AD) were synthesized in surfactant microemulsions in heptane. Effects of the reaction duration, the microemulsion polar phase volume, and concentrations of enzymes and modifiers on the properties of these conjugates were studied. The catalytic properties of conjugates depended on the nature of the surfactants used to stabilize the microemulsions, the initial concentration of protein in the reaction mixture, and the enzyme: modifier ratio. The degree of modification of the enzymes and the stabilities of their conjugates during isolation from microemulsions by a water-acetone solution depended on the concentration of the AD used. The catalytic properties of the conjugates synthesized were compared, and their stabilities in the presence of H2O2 were described. We suggested a simple method of transformation of whole kinetic curves of H2O2 conversion in coordinates 1/ln([H2O2]0/[H2O2]t - 1/t for simultaneous measurement of the constant of the catalase inactivation rate by H2O2 (Cin, S-1) and the rate constant of the catalase complex 1 interaction with the second H2O2 molecule (C2, M-1 S-1). This method was tested experimentally. Values C2 and Cin for catalase and its conjugates with ADs were compared, and these results were discussed.

  10. Use of biotin targeted methotrexate–human serum albumin conjugated nanoparticles to enhance methotrexate antitumor efficacy

    Science.gov (United States)

    Taheri, Azade; Dinarvand, Rassoul; Nouri, Faranak Salman; Khorramizadeh, Mohammad Reza; Borougeni, Atefeh Taheri; Mansoori, Pooria; Atyabi, Fatemeh

    2011-01-01

    Biotin molecules could be used as suitable targeting moieties in targeted drug delivery systems against tumors. To develop a biotin targeted drug delivery system, we employed human serum albumin (HSA) as a carrier. Methotrexate (MTX) molecules were conjugated to HSA. MTX-HSA nanoparticles (MTX-HSA NPs) were prepared from these conjugates by cross-linking the HSA molecules. Biotin molecules were then conjugated on the surface of MTX-HSA NPs. The anticancer efficacy of biotin targeted MTX-HSA NPs was evaluated in mice bearing 4T1 breast carcinoma. A single dose of biotin targeted MTX-HSA NPs showed stronger in vivo antitumor activity than non-targeted MTX-HSA NPs and free MTX. By 7 days after treatment, average tumor volume in the biotin targeted MTX-HSA NPs-treated group decreased to 17.6% of the initial tumor volume when the number of attached biotin molecules on MTX-HSA-NPs was the highest. Average tumor volume in non-targeted MTX-HSA NPs-treated mice grew rapidly and reached 250.7% of the initial tumor volume. Biotin targeted MTX-HSA NPs increased the survival of tumor-bearing mice to 47.5 ± 0.71 days and increased their life span up to 216.7%. Mice treated with biotin targeted MTX-HSA NPs showed slight body weight loss (8%) 21 days after treatment, whereas non-targeted MTX-HSA NPs treatment at the same dose caused a body weight loss of 27.05% ± 3.1%. PMID:21931482

  11. Small-molecule azomethines : Organic photovoltaics via Schiff base condensation chemistry

    NARCIS (Netherlands)

    Petrus, M.L.; Bouwer, R.K.M.; Lafont, U.; Athanasopoulos, S.; Greenham, N.C.; Dingemans, T.J.

    2014-01-01

    Conjugated small-molecule azomethines for photovoltaic applications were prepared via Schiff base condensation chemistry. Bulk heterojunction (BHJ) devices exhibit efficiencies of 1.2% with MoOx as the hole-transporting layer. The versatility and simplicity of the chemistry is illustrated by

  12. Small-molecule azomethines: Organic photovoltaics via Schiff base condensation chemistry

    OpenAIRE

    Petrus, M.L.; Bouwer, R.K.M.; Lafont, U.; Athanasopoulos, S.; Greenham, N.C.; Dingemans, T.J.

    2014-01-01

    Conjugated small-molecule azomethines for photovoltaic applications were prepared via Schiff base condensation chemistry. Bulk heterojunction (BHJ) devices exhibit efficiencies of 1.2% with MoOx as the hole-transporting layer. The versatility and simplicity of the chemistry is illustrated by preparing a photovoltaic device directly from the reaction mixture without any form of workup.

  13. Single molecules and nanotechnology

    CERN Document Server

    Vogel, Horst

    2007-01-01

    This book focuses on recent advances in the rapidly evolving field of single molecule research. These advances are of importance for the investigation of biopolymers and cellular biochemical reactions, and are essential to the development of quantitative biology. Written by leading experts in the field, the articles cover a broad range of topics, including: quantum photonics of organic dyes and inorganic nanoparticles their use in detecting properties of single molecules the monitoring of single molecule (enzymatic) reactions single protein (un)folding in nanometer-sized confined volumes the dynamics of molecular interactions in biological cells The book is written for advanced students and scientists who wish to survey the concepts, techniques and results of single molecule research and assess them for their own scientific activities.

  14. Electron-molecule collisions

    CERN Document Server

    Takayanagi, Kazuo

    1984-01-01

    Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

  15. Molecules to Materials

    Indian Academy of Sciences (India)

    evolved as a new line of thinking wherein a single molecule or perhaps a collection .... In photonic communication processes, laser light has to be modulated and .... The author wishes to thank G Rajaram for a critical reading of the manuscript.

  16. Single-Molecule Spectroscopy

    Indian Academy of Sciences (India)

    IAS Admin

    overall absorption spectrum of a molecule is a superposition of many such sharp lines .... dilute solution of the enzyme and the substrate over few drops of silicone oil placed ..... Near-field Scanning Optical Microscopy (NSOM): Development.

  17. Quantum dot molecules

    CERN Document Server

    Wu, Jiang

    2014-01-01

    This book reviews recent advances in the exciting and rapidly growing field of quantum dot molecules (QDMs). It offers state-of-the-art coverage of novel techniques and connects fundamental physical properties with device design.

  18. Molecule of the Month

    Indian Academy of Sciences (India)

    Molecule of the Month - Adamantane - A Plastic Piece of Diamond. J Chandrasekhar. Volume 16 Issue 12 ... Keywords. Adamantane; diamondoid systems; plastic crystals. ... Resonance – Journal of Science Education | News. © 2017 Indian ...

  19. Mapping the Small Molecule Interactome by Mass Spectrometry.

    Science.gov (United States)

    Flaxman, Hope A; Woo, Christina M

    2018-01-16

    Mapping small molecule interactions throughout the proteome provides the critical structural basis for functional analysis of their impact on biochemistry. However, translation of mass spectrometry-based proteomics methods to directly profile the interaction between a small molecule and the whole proteome is challenging because of the substoichiometric nature of many interactions, the diversity of covalent and noncovalent interactions involved, and the subsequent computational complexity associated with their spectral assignment. Recent advances in chemical proteomics have begun fill this gap to provide a structural basis for the breadth of small molecule-protein interactions in the whole proteome. Innovations enabling direct characterization of the small molecule interactome include faster, more sensitive instrumentation coupled to chemical conjugation, enrichment, and labeling methods that facilitate detection and assignment. These methods have started to measure molecular interaction hotspots due to inherent differences in local amino acid reactivity and binding affinity throughout the proteome. Measurement of the small molecule interactome is producing structural insights and methods for probing and engineering protein biochemistry. Direct structural characterization of the small molecule interactome is a rapidly emerging area pushing new frontiers in biochemistry at the interface of small molecules and the proteome.

  20. Synthesis of nano-bio conjugates for drug delivery systems using gas-liquid interfacial discharge plasmas

    International Nuclear Information System (INIS)

    Kaneko, Toshiro; Chen, Qiang; Hatakeyama, Rikizo

    2012-01-01

    Size-controlled gold nanoparticles (AuNPs) covered with DNA are synthesized by using a pulse driven gas-liquid interfacial discharge plasma (GLIDP) to reduce an aqueous solution of chloroauric acid trihydrate with DNA. The size and the assembly of the AuNPs are found to be easily controlled by changing the DNA concentration in the aqueous solution. The synthesized AuNP-DNA conjugates are forced to be encapsulated into double-walled carbon nanotubes (DWNTs) by superimposing a positive DC voltage on the pulse voltage. The AuNP-DNA-conjugate encapsulated DWNTs can be utilized in drug delivery systems when DNA is used as a drug molecule.

  1. A DFT and QTAIM study of the adsorption of organic molecules over the copper-doped coronene and circumcoronene

    Science.gov (United States)

    Malček, Michal; Cordeiro, M. Natalia D. S.

    2018-01-01

    Graphene based materials are nowadays extensively studied because of their potential applications as gas sensors, biosensors or adsorbents. Doping the graphene surface with heteroatoms or transition metals can improve its electronic properties and chemical reactivity. Polyaromatic hydrocarbons coronene and circumcoronene can be used as models of tiny graphene quantum dots. The adsorption of a set of organic molecules (water, hydrogen peroxide, hydrogen sulfide, methanol, ethanol and oxygen molecule) over the copper-doped coronene and circumcoronene was theoretically studied using density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM). In the case of coronene, only one site was considered for the Cu-doping, whereas in the case of circumcoronene being a polyaromatic hydrocarbon composed of 54 carbon atoms, three different sites for Cu-doping were considered. For the systems under study, the adsorption of O2 was found energetically the most favorable, with energetic outcome ranging from -3.1 to -3.7 eV related to the position of dopant Cu atom. Changes in the topology of charge densities at Cu and in its vicinity after the adsorption of studied molecules were investigated in the framework of QTAIM. In addition, QTAIM analysis of bond critical points (BCP) was employed to study the character of the newly formed chemical bonds. The results of this study point out the suitability of Cu-doped graphene materials as sensors and/or adsorbents in practical applications.

  2. Electron-molecule collisions

    International Nuclear Information System (INIS)

    Shimamura, I.; Takayanagi, K.

    1984-01-01

    The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

  3. Antibody drug conjugates - Trojan horses in the war on cancer.

    Science.gov (United States)

    Iyer, U; Kadambi, V J

    2011-01-01

    Antibody drug conjugates (ADCs) consist of an antibody attached to a cytotoxic drug by means of a linker. ADCs provide a way to couple the specificity of a monoclonal antibody (mAb) to the cytotoxicity of a small-molecule drug and, therefore, are promising new therapies for cancer. ADCs are prodrugs that are inactive in circulation but exert their cytotoxicity upon binding to the target cancer cell. Earlier unsuccessful attempts to generate ADCs with therapeutic value have emphasized the important role each component plays in determining the efficacy and safety of the final ADC. Scientific advances in engineering antibodies for maximum efficacy as anticancer agents, identification of highly cytotoxic molecules, and generation of linkers with increased stability in circulation have all contributed to the development of the many ADCs that are currently in clinical trials. This review discusses parameters that guide the selection of the components of an ADC to increase its therapeutic window, provides a brief look at ADCs currently in clinical trials, and discusses future challenges in this field. Copyright © 2011. Published by Elsevier Inc.

  4. Charge transport through molecular rods with reduced pi-conjugation.

    Science.gov (United States)

    Lörtscher, Emanuel; Elbing, Mark; Tschudy, Meinrad; von Hänisch, Carsten; Weber, Heiko B; Mayor, Marcel; Riel, Heike

    2008-10-24

    A series of oligophenylene rods of increasing lengths is synthesized to investigate the charge-transport mechanisms. Methyl groups are attached to the phenyl rings to weaken the electronic overlap of the pi-subsystems along the molecular backbones. Out-of-plane rotation of the phenyl rings is confirmed in the solid state by means of X-ray analysis and in solution by using UV/Vis spectroscopy. The influence of the reduced pi-conjugation on the resonant charge transport is studied at the single-molecule level by using the mechanically controllable break-junction technique. Experiments are performed under ultra-high-vacuum conditions at low temperature (50 K). A linear increase of the conductance gap with increasing number of phenyl rings (from 260 meV for one ring to 580 meV for four rings) is revealed. In addition, the absolute conductance of the first resonant peaks does not depend on the length of the molecular wire. Resonant transport through the first molecular orbital is found to be dominated by charge-carrier injection into the molecule, rather than by the intrinsic resistance of the molecular wire length.

  5. Clicked bis-PEG-peptide conjugates for studying calmodulin-Kv7.2 channel binding.

    Science.gov (United States)

    Bonache, M Angeles; Alaimo, Alessandro; Malo, Covadonga; Millet, Oscar; Villarroel, Alvaro; González-Muñiz, Rosario

    2014-11-28

    The recombinant Kv7.2 calmodulin (CaM) binding site (Q2AB CaMBD) shows a high tendency to aggregate, thus complicating biochemical and structural studies. To facilitate these studies we have conceived bis-PEG-peptide CaMBD-mimetics linking helices A and B in single, easy to handle molecules. Short PEG chains were selected as spacers between the two peptide molecules, and a Cu(i)-catalyzed cycloaddition (CuAAC) protocol was used to assemble the final bis-PEG-peptide conjugate, by the convenient functionalization of PEG arms with azide and alkyne groups. The resulting conjugates, with a certain helical character in TFE solutions (CD), showed nanomolar affinity in a fluorescence CaM binding in vitro assay, higher than just the sum of the precursor PEG-peptide affinities, thus validating our design. The approach to these first described examples of Kv7.2 CaMBD-mimetics could pave the way to chimeric conjugates merging helices A and B from different Kv7 subunits.

  6. Fluctuating exciton localization in giant π-conjugated spoked-wheel macrocycles

    Science.gov (United States)

    Aggarwal, A. Vikas; Thiessen, Alexander; Idelson, Alissa; Kalle, Daniel; Würsch, Dominik; Stangl, Thomas; Steiner, Florian; Jester, Stefan-S.; Vogelsang, Jan; Höger, Sigurd; Lupton, John M.

    2013-11-01

    Conjugated polymers offer potential for many diverse applications, but we still lack a fundamental microscopic understanding of their electronic structure. Elementary photoexcitations (excitons) span only a few nanometres of a molecule, which itself can extend over microns, and how their behaviour is affected by molecular dimensions is not immediately obvious. For example, where is the exciton formed within a conjugated segment and is it always situated on the same repeat units? Here, we introduce structurally rigid molecular spoked wheels, 6 nm in diameter, as a model of extended π conjugation. Single-molecule fluorescence reveals random exciton localization, which leads to temporally varying emission polarization. Initially, this random localization arises after every photon absorption event because of temperature-independent spontaneous symmetry breaking. These fast fluctuations are slowed to millisecond timescales after prolonged illumination. Intramolecular heterogeneity is revealed in cryogenic spectroscopy by jumps in transition energy, but emission polarization can also switch without a spectral jump occurring, which implies long-range homogeneity in the local dielectric environment.

  7. MOLECULES IN η CARINAE

    International Nuclear Information System (INIS)

    Loinard, Laurent; Menten, Karl M.; Güsten, Rolf; Zapata, Luis A.; Rodríguez, Luis F.

    2012-01-01

    We report the detection toward η Carinae of six new molecules, CO, CN, HCO + , HCN, HNC, and N 2 H + , and of two of their less abundant isotopic counterparts, 13 CO and H 13 CN. The line profiles are moderately broad (∼100 km s –1 ), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO + do not appear to be underabundant in η Carinae. On the other hand, molecules containing nitrogen or the 13 C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of η Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

  8. Analytical characterization of polymer-drug conjugates

    International Nuclear Information System (INIS)

    Rizzo, V.; Gigli, M.; Pinciroli, V.

    1998-01-01

    A few polymeric conjugates of antitumor drugs have been recently developed in view of possible therapeutic advantages: solubilization of sparingly soluble drugs in water, improvement of therapeutic index, organ targeting through a second chemical species bound to the same polymeric chain. In this article it's described the analytical approach used in the characterization of the conjugates for chemical identity, purity and strength of the contained active ingredient. The techniques are: high field NMR and size exclusion chromatography with non-aqueous mobile phase for identity; selective hydrolysis and HPLC for strength and purity. A complete and reliable picture is thus obtained both for qualitative and for quantitative aspects. This is an important step forward in the direction of further development and marketing of polymer-drug conjugates [it

  9. Nonlinear conjugate gradient methods in micromagnetics

    Directory of Open Access Journals (Sweden)

    J. Fischbacher

    2017-04-01

    Full Text Available Conjugate gradient methods for energy minimization in micromagnetics are compared. The comparison of analytic results with numerical simulation shows that standard conjugate gradient method may fail to produce correct results. A method that restricts the step length in the line search is introduced, in order to avoid this problem. When the step length in the line search is controlled, conjugate gradient techniques are a fast and reliable way to compute the hysteresis properties of permanent magnets. The method is applied to investigate demagnetizing effects in NdFe12 based permanent magnets. The reduction of the coercive field by demagnetizing effects is μ0ΔH = 1.4 T at 450 K.

  10. Conjugate Meningococcal Vaccines Development: GSK Biologicals Experience

    Science.gov (United States)

    Miller, Jacqueline M.; Mesaros, Narcisa; Van Der Wielen, Marie; Baine, Yaela

    2011-01-01

    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. PMID:21991444

  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. 125I Radioimmunoassay of serum ursodeoxycholyl conjugates

    International Nuclear Information System (INIS)

    Hill, A.; Ross, P.E.; Bouchier, I.A.D.

    1983-01-01

    A radioimmunoassay for serum ursodeoxycholic conjugates using an iodine-125 ligand has been developed. The bile acid was present in normal fasting serum (0.19 +- SD 0.19 μmol/l, n=24) and 2-hour post-prandial serum (0.8 +- SD 0.8 μmol/l, n=16). Gallstone patients undergoing oral ursodeoxycholic acid therapy had significantly higher post-prandial serum levels (21.5 +- SD 14.0 μmol/l, n=15) by radioimmunoassay. Gas liquid chromatography analysis indicated that in normal serum ursodeoxycholic acid was totally conjugated, whereas sera from gallstone patients contained a proportion as the free bile acid (10.2 +- SD 8.1 μmol/l, n=15). Following an oral dose of ursodeoxycholic acid, both unconjugated and conjugated forms of the bile acid appeared in the serum of healthy individuals. (Auth.)

  13. Novel β-cyclodextrin–eosin conjugates

    Directory of Open Access Journals (Sweden)

    Gábor Benkovics

    2017-03-01

    Full Text Available Eosin B (EoB and eosin Y (EoY, two xanthene dye derivatives with photosensitizing ability were prepared in high purity through an improved synthetic route. The dyes were grafted to a 6-monoamino-β-cyclodextrin scaffold under mild reaction conditions through a stable amide linkage using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl-4-methylmorpholinium chloride. The molecular conjugates, well soluble in aqueous medium, were extensively characterized by 1D and 2D NMR spectroscopy and mass spectrometry. Preliminary spectroscopic investigations showed that the β-cyclodextrin–EoY conjugate retains both the fluorescence properties and the capability to photogenerate singlet oxygen of the unbound chromophore. In contrast, the corresponding β-cyclodextrin–EoB conjugate did not show either relevant emission or photosensitizing activity probably due to aggregation in aqueous medium, which precludes any response to light excitation.

  14. Novel β-cyclodextrin-eosin conjugates.

    Science.gov (United States)

    Benkovics, Gábor; Afonso, Damien; Darcsi, András; Béni, Szabolcs; Conoci, Sabrina; Fenyvesi, Éva; Szente, Lajos; Malanga, Milo; Sortino, Salvatore

    2017-01-01

    Eosin B (EoB) and eosin Y (EoY), two xanthene dye derivatives with photosensitizing ability were prepared in high purity through an improved synthetic route. The dyes were grafted to a 6-monoamino-β-cyclodextrin scaffold under mild reaction conditions through a stable amide linkage using the coupling agent 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The molecular conjugates, well soluble in aqueous medium, were extensively characterized by 1D and 2D NMR spectroscopy and mass spectrometry. Preliminary spectroscopic investigations showed that the β-cyclodextrin-EoY conjugate retains both the fluorescence properties and the capability to photogenerate singlet oxygen of the unbound chromophore. In contrast, the corresponding β-cyclodextrin-EoB conjugate did not show either relevant emission or photosensitizing activity probably due to aggregation in aqueous medium, which precludes any response to light excitation.

  15. Deciphering conjugative plasmid permissiveness in wastewater microbiomes

    DEFF Research Database (Denmark)

    Jacquiod, Samuel Jehan Auguste; Brejnrod, Asker Daniel; Milani, Stefan Morberg

    2017-01-01

    Wastewater treatment plants (WWTPs) are designed to robustly treat polluted water. They are characterized by ceaseless flows of organic, chemical and microbial matter, followed by treatment steps before environmental release. WWTPs are hotspots of horizontal gene transfer between bacteria via...... still remains largely uncharted. Furthermore, current in vitro methods used to assess conjugation in complex microbiomes do not include in situ behaviours of recipient cells, resulting in partial understanding of transfers. We investigated the in vitro conjugation capacities of WWTP microbiomes from...... inlet sewage and outlet treated water using the broad-host range IncP-1 conjugative plasmid, pKJK5. A thorough molecular approach coupling metagenomes to 16S rRNA DNA/cDNA amplicon sequencing was established to characterize microbiomes using the ecological concept of functional response groups. A broad...

  16. 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.

  17. Electron Accumulative Molecules.

    Science.gov (United States)

    Buades, Ana B; Sanchez Arderiu, Víctor; Olid-Britos, David; Viñas, Clara; Sillanpää, Reijo; Haukka, Matti; Fontrodona, Xavier; Paradinas, Markos; Ocal, Carmen; Teixidor, Francesc

    2018-02-28

    With the goal to produce molecules with high electron accepting capacity and low reorganization energy upon gaining one or more electrons, a synthesis procedure leading to the formation of a B-N(aromatic) bond in a cluster has been developed. The research was focused on the development of a molecular structure able to accept and release a specific number of electrons without decomposing or change in its structural arrangement. The synthetic procedure consists of a parallel decomposition reaction to generate a reactive electrophile and a synthesis reaction to generate the B-N(aromatic) bond. This procedure has paved the way to produce the metallacarboranylviologen [M(C 2 B 9 H 11 )(C 2 B 9 H 10 )-NC 5 H 4 -C 5 H 4 N-M'(C 2 B 9 H 11 )(C 2 B 9 H 10 )] (M = M' = Co, Fe and M = Co and M' = Fe) and semi(metallacarboranyl)viologen [3,3'-M(8-(NC 5 H 4 -C 5 H 4 N-1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] (M = Co, Fe) electron cumulative molecules. These molecules are able to accept up to five electrons and to donate one in single electron steps at accessible potentials and in a reversible way. By targeted synthesis and corresponding electrochemical tests each electron transfer (ET) step has been assigned to specific fragments of the molecules. The molecules have been carefully characterized, and the electronic communication between both metal centers (when this situation applies) has been definitely observed through the coplanarity of both pyridine fragments. The structural characteristics of these molecules imply a low reorganization energy that is a necessary requirement for low energy ET processes. This makes them electronically comparable to fullerenes, but on their side, they have a wide range of possible solvents. The ET from one molecule to another has been clearly demonstrated as well as their self-organizing capacity. We consider that these molecules, thanks to their easy synthesis, ET, self-organizing capacity, wide range of solubility, and easy processability, can

  18. METHOD OF CONJUGATED CIRCULAR ARCS TRACING

    Directory of Open Access Journals (Sweden)

    N. Ageyev Vladimir

    2017-01-01

    Full Text Available The geometric properties of conjugated circular arcs connecting two points on the plane with set directions of tan- gent vectors are studied in the work. It is shown that pairs of conjugated circular arcs with the same conditions in frontier points create one-parameter set of smooth curves tightly filling all the plane. One of the basic properties of this set is the fact that all coupling points of circular arcs are on the circular curve going through the initially given points. The circle radius depends on the direction of tangent vectors. Any point of the circle curve, named auxiliary in this work, determines a pair of conjugated arcs with given boundary conditions. One more condition of the auxiliary circle curve is that it divides the plane into two parts. The arcs going from the initial point are out of the circle limited by this circle curve and the arcs coming to the final point are inside it. These properties are the basis for the method of conjugated circular arcs tracing pro- posed in this article. The algorithm is rather simple and allows to fulfill all the needed plottings using only the divider and ruler. Two concrete examples are considered. The first one is related to the problem of tracing of a pair of conjugated arcs with the minimal curve jump when going through the coupling point. The second one demonstrates the possibility of trac- ing of the smooth curve going through any three points on the plane under condition that in the initial and final points the directions of tangent vectors are given. The proposed methods of conjugated circular arcs tracing can be applied in solving of a wide variety of problems connected with the tracing of cam contours, for example pattern curves in textile industry or in computer-aided-design systems when programming of looms with numeric control.

  19. Conjugated Polymers as Actuators: Modes of Actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2004-01-01

    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...

  20. 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...

  1. Functionalized conjugated polyelectrolytes design and biomedical applications

    CERN Document Server

    Wang, Shu

    2014-01-01

    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 research and application issues. Functionalized conjugated polyelectrolyte materials, which have already drawn considerable interest, will become a major new direction for biomedicine development.

  2. Carbon K-shell photoionization of CO: Molecular frame angular distributions of normal and conjugate shakeup satellites

    International Nuclear Information System (INIS)

    Jahnke, T.; Titze, J.; Foucar, L.; Wallauer, R.; Osipov, T.; Benis, E.P.; Jagutzki, O.; Arnold, W.; Czasch, A.; Staudte, A.; Schoeffler, M.; Alnaser, A.; Weber, T.; Prior, M.H.; Schmidt-Boecking, H.; Doerner, R.

    2011-01-01

    We have measured the molecular frame angular distributions of photoelectrons emitted from the Carbon K-shell of fixed-in-space CO molecules for the case of simultaneous excitation of the remaining molecular ion. Normal and conjugate shakeup states are observed. Photoelectrons belonging to normal Σ-satellite lines show an angular distribution resembling that observed for the main photoline at the same electron energy. Surprisingly a similar shape is found for conjugate shakeup states with Π-symmetry. In our data we identify shake rather than electron scattering (PEVE) as the mechanism producing the conjugate lines. The angular distributions clearly show the presence of a Σ shape resonance for all of the satellite lines.

  3. Single Molecule Atomic Force Microscopy Studies of Photosensitized Singlet Oxygen Behavior on a DNA Origami Template

    DEFF Research Database (Denmark)

    Helmig, Sarah Wendelboe; Rotaru, Alexandru; Arian, Dumitru

    2010-01-01

    DNA origami, the folding of a long single-stranded DNA sequence (scaffold strand) by hundreds of short synthetic oligonucleotides (staple strands) into parallel aligned helices, is a highly efficient method to form advanced self-assembled DNA-architectures. Since molecules and various materials can...... be conjugated to each of the short staple strands, the origami method offers a unique possibility of arranging molecules and materials in well-defined positions on a structured surface. Here we combine the action of light with AFM and DNA nanostructures to study the production of singlet oxygen from a single...... photosensitizer molecule conjugated to a selected DNA origami staple strand on an origami structure. We demonstrate a distance-dependent oxidation of organic moieties incorporated in specific positions on DNA origami by singlet oxygen produced from a single photosensitizer located at the center of each origami....

  4. Energetic Analysis of Conjugated Hydrocarbons Using the Interacting Quantum Atoms Method.

    Science.gov (United States)

    Jara-Cortés, Jesús; Hernández-Trujillo, Jesús

    2018-07-05

    A number of aromatic, antiaromatic, and nonaromatic organic molecules was analyzed in terms of the contributions to the electronic energy defined in the quantum theory of atoms in molecules and the interacting quantum atoms method. Regularities were found in the exchange and electrostatic interatomic energies showing trends that are closely related to those of the delocalization indices defined in the theory. In particular, the CC interaction energies between bonded atoms allow to rationalize the energetic stabilization associated with the bond length alternation in conjugated polyenes. This approach also provides support to Clar's sextet rules devised for aromatic systems. In addition, the H⋯H bonding found in some of the aromatic molecules studied was of an attractive nature, according to the stabilizing exchange interaction between the bonded H atoms. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Protective Effect of Vitamin D3 and Gp63 Conjugated with Tetanus Toxoid on Outcome of Cutaneous Leishmaniasis Lesions in Balb/C Mice

    Directory of Open Access Journals (Sweden)

    S Soudi

    2006-01-01

    Full Text Available Introduction: GP63 is a major surface protease of Leishmania promastigotes that plays an important role in its virulance. As GP63 on its own can not develop an effective protection against leishmaniasis, the goal of this study was to evaluate the protective effect of GP63 conjugated with tetanus toxoid (TT and Vitamin D3 in susceptible BALB/c mice against cutaneous leishmaniasis. Methods: This study was a basic-applied experimental study performed in Tarbiat Modarres University from September 2002 to April 2005. Cloned virulant Leishmania (L. major [MRHO / IR / 75 / ER] strain was cultured and 5109 cells were harvested. GP63 Molecule was purified and conjugated with TT and conjugated molecule was used for immunization of 8 groups of female BALB/c mice. Results: Results showed that the group of mice receiving conjugated molecule with Vitamin D3 had significant differences from other groups regarding lesion progression (P0.05. The culture of spleen cells showed that the disease did not become systemic in this group. Conclusion: Conjugation of GP63 with TT strengthens cell immunity and its use along with vitamin D3 provokes macrophages activity. This basis can be used for production of an appropriate preparation for protection against Leishmaniasis.

  6. Molecule of the Month

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. Molecule of the Month Isomers of Benzene - Still Pursuing Dreams. J Chandrasekhar. Feature Article Volume 1 Issue 2 February 1996 pp 80-83. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  8. Electrons in Molecules

    Indian Academy of Sciences (India)

    structure and properties (includingreactivt'ty) - both static (independent of time) and ... Furthermore, since the energy of H2 + in the ground state must be lower than that of .... (Figure 2b); note also that dp is positive in parts of the antibinding regions behind the two ... But, now both the sizes and shapes of molecules enter into.

  9. Molecule of the Month

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule of the Month - A Stable Dibismuthene - A Compound with a Bi-Bi Double Bond. V Chandrasekhar. Volume 16 ... Author Affiliations. V Chandrasekhar1. Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India.

  10. OMG: Open molecule generator

    NARCIS (Netherlands)

    Peironcely, J.E.; Rojas-Chertó, M.; Fichera, D.; Reijmers, T.; Coulier, L.; Faulon, J.-L.; Hankemeier, T.

    2012-01-01

    Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical

  11. Molecule-based magnets

    Indian Academy of Sciences (India)

    Administrator

    Employing self-assembly methods, it is possible to engineer a bulk molecular material ... synthesis of molecular magnets in 1986, a large variety of them have been synthesized, which can be catego- ... maintained stably per organic molecule, stabilization of a ..... rotating freely under an applied field because it is a magne-.

  12. Molecule of the Month

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 5. Molecule of the Month Molecular–Chameleon: Solvatochromism at its Iridescent Best! Photon Rao. Feature Article Volume 2 Issue 5 May 1997 pp 69-72. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Peptide-mediated vectorization of metal complexes: conjugation strategies and biomedical applications.

    Science.gov (United States)

    Soler, Marta; Feliu, Lidia; Planas, Marta; Ribas, Xavi; Costas, Miquel

    2016-08-16

    The rich chemical and structural versatility of transition metal complexes provides numerous novel paths to be pursued in the design of molecules that exert particular chemical or physicochemical effects that could operate over specific biological targets. However, the poor cell permeability of metallodrugs represents an important barrier for their therapeutic use. The conjugation between metal complexes and a functional peptide vector can be regarded as a versatile and potential strategy to improve their bioavailability and accumulation inside cells, and the site selectivity of their effect. This perspective lies in reviewing the recent advances in the design of metallopeptide conjugates for biomedical applications. Additionally, we highlight the studies where this approach has been directed towards the incorporation of redox active metal centers into living organisms for modulating the cellular redox balance, as a tool with application in anticancer therapy.

  14. Novel two-step synthesis of gold nanoparticles capped with bile acid conjugates

    International Nuclear Information System (INIS)

    Noponen, Virpi; Bhat, Shreedhar; Sievaenen, Elina; Kolehmainen, Erkki

    2008-01-01

    Bile acids and their conjugates are physiologically important molecules. Syntheses and structure elucidation combined with investigation of properties and applications of bile acids and their derivatives are of academic interest. The concept of using bile acids and their conjugates in nanoscience is a novel idea, which opens up fascinating prospects. In this article, an easy and simple route for obtaining N-lithocholyl-L-(cysteine ethyl ester) (3), capable of effectively capping and stabilizing metal nanoparticles, is described. The whole synthetic route needs only two steps giving a moderate to good yield. The gold NPs are characterized by elemental analysis, UV spectroscopy, and TEM. Additionally, 13 C CP/MAS NMR studies for different ligand/Au ratios have been performed

  15. Peptide-Conjugated Nanoparticles Reduce Positive Co-stimulatory Expression and T Cell Activity to Induce Tolerance.

    Science.gov (United States)

    Kuo, Robert; Saito, Eiji; Miller, Stephen D; Shea, Lonnie D

    2017-07-05

    Targeted approaches to treat autoimmune diseases would improve upon current therapies that broadly suppress the immune system and lead to detrimental side effects. Antigen-specific tolerance was induced using poly(lactide-co-glycolide) nanoparticles conjugated with disease-relevant antigen to treat a model of multiple sclerosis. Increasing the nanoparticle dose and amount of conjugated antigen both resulted in more durable immune tolerance. To identify active tolerance mechanisms, we investigated downstream cellular and molecular events following nanoparticle internalization by antigen-presenting cells. The initial cell response to nanoparticles indicated suppression of inflammatory signaling pathways. Direct and functional measurement of surface MHC-restricted antigen showed positive correlation with both increasing particle dose from 1 to 100 μg/mL and increasing peptide conjugation by 2-fold. Co-stimulatory analysis of cells expressing MHC-restricted antigen revealed most significant decreases in positive co-stimulatory molecules (CD86, CD80, and CD40) following high doses of nanoparticles with higher peptide conjugation, whereas expression of a negative co-stimulatory molecule (PD-L1) remained high. T cells isolated from mice immunized against myelin proteolipid protein (PLP 139-151 ) were co-cultured with antigen-presenting cells administered PLP 139-151 -conjugated nanoparticles, which resulted in reduced T cell proliferation, increased T cell apoptosis, and a stronger anti-inflammatory response. These findings indicate several potential mechanisms used by peptide-conjugated nanoparticles to induce antigen-specific tolerance. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

  16. Exotic helium molecules

    International Nuclear Information System (INIS)

    Portier, M.

    2007-12-01

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range 4 He 2 (2 3 S 1 -2 3 P 0 ) molecule, or a 4 He 2 (2 3 S 1 -2 3 S 1 ) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 ± 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range 4 He 2 (2 3 S 1 -2 3 S 1 ) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime τ = (1.4 ± 0.3) μs is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  17. OMG: Open Molecule Generator.

    Science.gov (United States)

    Peironcely, Julio E; Rojas-Chertó, Miguel; Fichera, Davide; Reijmers, Theo; Coulier, Leon; Faulon, Jean-Loup; Hankemeier, Thomas

    2012-09-17

    Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck.

  18. OMG: Open Molecule Generator

    Directory of Open Access Journals (Sweden)

    Peironcely Julio E

    2012-09-01

    Full Text Available Abstract Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG, which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck.

  19. Photoacoustic tomography of joints aided by an Etanercept-conjugated gold nanoparticle contrast agent-an ex vivo preliminary rat study

    International Nuclear Information System (INIS)

    Chamberland, David L; Agarwal, Ashish; Kotov, Nicholas; Fowlkes, J Brian; Carson, Paul L; Wang Xueding

    2008-01-01

    Monitoring of anti-rheumatic drug delivery in experimental models and in human diseases would undoubtedly be very helpful for both basic research and clinical management of inflammatory diseases. In this study, we have investigated the potential of an emerging hybrid imaging technology-photoacoustic tomography-in noninvasive monitoring of anti-TNF drug delivery. After the contrast agent composed of gold nanorods conjugated with Etanercept molecules was produced, ELISA experiments were performed to prove the conjugation and to show that the conjugated anti-TNF-α drug was biologically active. PAT of ex vivo rat tail joints with the joint connective tissue enhanced by intra-articularly injected contrast agent was conducted to examine the performance of PAT in visualizing the distribution of the gold-nanorod-conjugated drug in articular tissues. By using the described system, gold nanorods with a concentration down to 1 pM in phantoms or 10 pM in biological tissues can be imaged with good signal-to-noise ratio and high spatial resolution. This study demonstrates the feasibility of conjugating TNF antagonist pharmaceutical preparations with gold nanorods, preservation of the mechanism of action of TNF antagonist along with preliminary evaluation of novel PAT technology in imaging optical contrast agents conjugated with anti-rheumatic drugs. Further in vivo studies on animals are warranted to test the specific binding between such conjugates and targeted antigen in joint tissues affected by inflammation

  20. Single Molecule Nanoelectrochemistry in Electrical Junctions.

    Science.gov (United States)

    Nichols, Richard J; Higgins, Simon J

    2016-11-15

    gating. This has been referred to as to a "single molecule transistor configuration" with the gate voltage being provided by the controllable potential achieved through the electrochemical double layer. It is shown how the electrolyte medium can control such gating, with ionic liquids providing more efficient gate coupling than aqueous electrolytes. Control of the conductance of viologen molecular wires can also be achieved by encapsulating the viologen redox moiety within a molecular cage, thereby controlling its immediate environment. Molecular conductance can also be gated through multiple redox states. This has been shown for the redox moiety pyrrolo-tetrathiafulvalene, which undergoes single molecule electrochemical transistor gating through three redox states in molecular junctions. Charge transport through this junction follows a two-step hopping mechanism, demonstrating the role of the redox center in electron transfer across the molecular bridge. Recent electrolyte gating studies of rigid, conjugated redox-active metal complexes with tailored terpyridine coordinating ligands and anchors are also presented. These aforementioned studies have all been performed with gold electrode contacts. The Account concludes with recent data showing that it is now possible to study single molecule electrochemical gating with nickel electrodes. This opens up new perspectives for studying interfacial charge transfer with a wide variety of other electrode materials including semiconductor electrodes and also points toward future opportunities for coupling molecular spintronics and nanoelectrochemistry.

  1. Membrane Transporters for Bilirubin and Its Conjugates: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Jovana Čvorović

    2017-12-01

    Full Text Available Background: Bilirubin is a highly-hydrophobic tetrapyrrole which binds to plasma albumin. It is conjugated in the liver to glucuronic acid, and the water-soluble glucuronides are excreted in urine and bile. The membrane transporters of bilirubin diglucuronide are well-known. Still undefined are however the transporters performing the uptake of bilirubin from the blood into the liver, a process known to be fast and not rate-limited. The biological importance of this process may be appraised by considering that in normal adults 200–300 mg of bilirubin are produced daily, as a result of the physiologic turnover of hemoglobin and cellular cytochromes. Nevertheless, research in this field has yielded controversial and contradicting results. We have undertaken a systematic review of the literature, believing in its utility to improve the existing knowledge and promote further advancements.Methods: We have sourced the PubMed database until 30 June 2017 by applying 5 sequential searches. Screening and eligibility criteria were applied to retain research articles reporting results obtained by using bilirubin molecules in membrane transport assays in vitro or by assessing serum bilirubin levels in in vivo experiments.Results: We have identified 311 articles, retaining 44, reporting data on experimental models having 6 incremental increases of complexity (isolated proteins, membrane vesicles, cells, organ fragments, in vivo rodents, and human studies, demonstrating the function of 19 membrane transporters, encoded by either SLCO or ABC genes. Three other bilirubin transporters have no gene, though one, i.e., bilitranslocase, is annotated in the Transporter Classification Database.Conclusions: This is the first review that has systematically examined the membrane transporters for bilirubin and its conjugates. Paradoxically, the remarkable advancements in the field of membrane transport of bilirubin have pointed to the elusive mechanism(s enabling

  2. Plasmid transfer by conjugation in Xylella fastidiosa.

    Science.gov (United States)

    Recombination and horizontal gene transfer have been implicated in the adaption of Xylella fastidiosa (Xf) to infect a wide variety of different plant species. There is evidence that certain strains of Xf carry native plasmids equipped with transfer and mobilization genes, suggesting conjugation as ...

  3. Theory of periodic conjugate heat transfer

    CERN Document Server

    Zudin, Yuri B

    2016-01-01

    This book presents the theory of periodic conjugate heat transfer in detail. It offers 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.

  4. 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.

  5. 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...

  6. Immunogenicity of novel sulfadimethoxide conjugates | Chen ...

    African Journals Online (AJOL)

    Immunogenicity of novel sulfadimethoxide conjugates. L Chen, J Su, X Zhang, L Li, X He. Abstract. Sulfadimethoxine (SDM) is an antibiotic commonly added to animal feeds. Anti-SDM antibodies are useful for the detection of residual SDM in foods, feeds and biological fluids by ELISA. In this study, we show that SDM is ...

  7. 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.

  8. Integrated circuits based on conjugated polymer monolayer.

    Science.gov (United States)

    Li, Mengmeng; Mangalore, Deepthi Kamath; Zhao, Jingbo; Carpenter, Joshua H; Yan, Hongping; Ade, Harald; Yan, He; Müllen, Klaus; Blom, Paul W M; Pisula, Wojciech; de Leeuw, Dago M; Asadi, Kamal

    2018-01-31

    It is still a great challenge to fabricate conjugated polymer monolayer field-effect transistors (PoM-FETs) due to intricate crystallization and film formation of conjugated polymers. Here we demonstrate PoM-FETs based on a single monolayer of a conjugated polymer. The resulting PoM-FETs are highly reproducible and exhibit charge carrier mobilities reaching 3 cm 2  V -1  s -1 . The high performance is attributed to the strong interactions of the polymer chains present already in solution leading to pronounced edge-on packing and well-defined microstructure in the monolayer. The high reproducibility enables the integration of discrete unipolar PoM-FETs into inverters and ring oscillators. Real logic functionality has been demonstrated by constructing a 15-bit code generator in which hundreds of self-assembled PoM-FETs are addressed simultaneously. Our results provide the state-of-the-art example of integrated circuits based on a conjugated polymer monolayer, opening prospective pathways for bottom-up organic electronics.

  9. 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.

  10. Compositions for directed alignment of conjugated polymers

    Science.gov (United States)

    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).

  11. Conjugate Gradient Algorithms For Manipulator Simulation

    Science.gov (United States)

    Fijany, Amir; Scheid, Robert E.

    1991-01-01

    Report discusses applicability of conjugate-gradient algorithms to computation of forward dynamics of robotic manipulators. Rapid computation of forward dynamics essential to teleoperation and other advanced robotic applications. Part of continuing effort to find algorithms meeting requirements for increased computational efficiency and speed. Method used for iterative solution of systems of linear equations.

  12. 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...

  13. Some aspects of geomagnetically conjugate phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Rycroft, M.J.

    1987-12-01

    Both charged particles and waves convey information about the thermosphere, ionosphere and magnetosphere from the Northern to the Southern Hemisphere and vice versa, along geomagnetic flux tubes.The interhemispheric travel time of electrons or ions, being dependent upon L-value , pitch angle and energy (which may lie between less than or equal to 1 eV and greater than or equal to 1 MeV) may be many hours, ranging down to less than or equal to 1 s. However, the one-hop propagation time for magnetohydrodynamic or whistler mode waves generally lies between 10/sup 2/s and 1 s. Such times, therefore, give the time scales of transient phenomena that are geomagnetically conjugate and of changes in steady-state plasma processes occurring in geomagnetically conjugate regions. Contrasting examples are presented of conjugate physical phenomena, obtained using satellite, rocket, aircraft and ground-based observations; the latter capitalise upon the rather rare disposition of land - rather than ocean - at each end of a geophysically interesting flux tube. Particular attention is paid to the interactions between whistler mode waves and energetic electrons. Geomagnetic, radio, optical and plasma observations, taken together with model computations, provide a wealth of knowledge on conjugate phenomena and their dependence on conditions in the solar wind, substorms, L-value, etc... Finally, some suggestions are made for future lines of research.

  14. Cross-Conjugated n-Dopable Aromatic Polyketone

    NARCIS (Netherlands)

    Voortman, Thomas P.; Bartesaghi, Davide; Koster, L. Jan Anton; Chiechi, Ryan C.

    2015-01-01

    This paper describes the synthesis and characterization of a high molecular weight cross-conjugated polyketone synthesized via scalable Friedel Crafts chemistry. Cross-conjugated polyketones are precursors to conjugated polyions; they become orders of magnitude more conductive after a two-electron

  15. Bis-polymer lipid-peptide conjugates and nanoparticles thereof

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Dong, He; Shu, Jessica; Dube, Nikhil

    2018-04-24

    The present invention provides bis-polymer lipid-peptide conjugates containing a hydrophobic block and headgroup containing a helical peptide and two polymer blocks. The conjugates can self-assemble to form helix bundle subunits, which in turn assemble to provide micellar nanocarriers for drug cargos and other agents. Particles containing the conjugates and methods for forming the particles are also disclosed.

  16. Production and characterization of a camelid single domain antibody-urease enzyme conjugate for the treatment of cancer.

    Science.gov (United States)

    Tian, Baomin; Wong, Wah Yau; Hegmann, Elda; Gaspar, Kim; Kumar, Praveen; Chao, Heman

    2015-06-17

    A novel immunoconjugate (L-DOS47) was developed and characterized as a therapeutic agent for tumors expressing CEACAM6. The single domain antibody AFAIKL2, which targets CEACAM6, was expressed in the Escherichia coli BL21 (DE3) pT7-7 system. High purity urease (HPU) was extracted and purified from Jack bean meal. AFAIKL2 was activated using N-succinimidyl [4-iodoacetyl] aminobenzoate (SIAB) as the cross-linker and then conjugated to urease. The activation and conjugation reactions were controlled by altering pH. Under these conditions, the material ratio achieved conjugation ratios of 8-11 antibodies per urease molecule, the residual free urease content was practically negligible (95%) L-DOS47 conjugate was produced using only ultradiafiltration to remove unreacted antibody and hydrolyzed cross-linker. L-DOS47 was characterized by a panel of analytical techniques including SEC, IEC, Western blot, ELISA, and LC-MS(E) peptide mapping. As the antibody-urease conjugate ratio increased, a higher binding signal was observed. The specificity and cytotoxicity of L-DOS47 was confirmed by screening in four cell lines (BxPC-3, A549, MCF7, and CEACAM6-transfected H23). BxPC-3, a CEACAM6-expressing cell line was found to be most susceptible to L-DOS47. L-DOS47 is being investigated as a potential therapeutic agent in human phase I clinical studies for nonsmall cell lung cancer.

  17. Curcumin Conjugated with PLGA Potentiates Sustainability, Anti-Proliferative Activity and Apoptosis in Human Colon Carcinoma Cells

    Science.gov (United States)

    Waghela, Bhargav N.; Sharma, Anupama; Dhumale, Suhashini; Pandey, Shashibahl M.; Pathak, Chandramani

    2015-01-01

    Curcumin, an ingredient of turmeric, exhibits a variety of biological activities such as anti-inflammatory, anti-atherosclerotic, anti-proliferative, anti-oxidant, anti-cancer and anti-metastatic. It is a highly pleiotropic molecule that inhibits cell proliferation and induces apoptosis in cancer cells. Despite its imperative biological activities, chemical instability, photo-instability and poor bioavailability limits its utilization as an effective therapeutic agent. Therefore, enhancing the bioavailability of curcumin may improve its therapeutic index for clinical setting. In the present study, we have conjugated curcumin with a biodegradable polymer Poly (D, L-lactic-co-glycolic acid) and evaluated its apoptotic potential in human colon carcinoma cells (HCT 116). The results show that curcumin-PLGA conjugate efficiently inhibits cell proliferation and cell survival in human colon carcinoma cells as compared to native curcumin. Additionally, curcumin conjugated with PLGA shows improved cellular uptake and exhibits controlled release at physiological pH as compared to native curcumin. The curcumin-PLGA conjugate efficiently activates the cascade of caspases and promotes intrinsic apoptotic signaling. Thus, the results suggest that conjugation potentiates the sustainability, anti-proliferative and apoptotic activity of curcumin. This approach could be a promising strategy to improve the therapeutic index of cancer therapy. PMID:25692854

  18. Single-Molecule Nanomagnets

    Science.gov (United States)

    Friedman, Jonathan R.; Sarachik, Myriam P.

    2010-04-01

    Single-molecule magnets straddle the classical and quantum mechanical worlds, displaying many fascinating phenomena. They may have important technological applications in information storage and quantum computation. We review the physical properties of two prototypical molecular nanomagnets, Mn12-acetate and Fe8: Each behaves as a rigid, spin-10 object and exhibits tunneling between up and down directions. As temperature is lowered, the spin-reversal process evolves from thermal activation to pure quantum tunneling. At low temperatures, magnetic avalanches occur in which the magnetization of an entire sample rapidly reverses. We discuss the important role that symmetry-breaking fields play in driving tunneling and in producing Berry-phase interference. Recent experimental advances indicate that quantum coherence can be maintained on timescales sufficient to allow a meaningful number of quantum computing operations to be performed. Efforts are under way to create monolayers and to address and manipulate individual molecules.

  19. Superexcited states of molecules

    International Nuclear Information System (INIS)

    Nakamura, Hiroki; Takagi, Hidekazu.

    1990-01-01

    The report addresses the nature and major features of molecule's superexcited states, focusing on their involvement in dynamic processes. It also outlines the quantum defect theory which allows various processes involving these states to be treated in a unified way. The Rydberg state has close relation with an ionized state with a positive energy. The quantum defect theory interprets such relation. Specifically, the report first describes the quantum defect theory focusing on its basic principle. The multi-channel quantum defect theory is then outlined centering on how to describe a Rydberg-type superexcited state. Description of a dissociative double-electron excited state is also discussed. The quantum defect theory is based on the fact that the physics of the motion of a Rydberg electron vary with the region in the electron's coordinate space. Finally, various molecular processes that involve a superexcited state are addressed focusing on autoionization, photoionization, dissociative recombination and bonding ionization of diatomic molecules. (N.K.)

  20. Modulation of mdm2 pre-mRNA splicing by 9-aminoacridine-PNA (peptide nucleic acid) conjugates targeting intron-exon junctions

    DEFF Research Database (Denmark)

    Shiraishi, Takehiko; Eysturskard, Jonhard; Nielsen, Peter E

    2010-01-01

    ABSTRACT: BACKGROUND: Modulation of pre-mRNA splicing by antisense molecules is a promising mechanism of action for gene therapeutic drugs. In this study, we have examined the potential of peptide nucleic acid (PNA) 9-aminoacridine conjugates to modulate the pre-mRNA splicing of the mdm2 human ca...

  1. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  2. Conjugation of Organic Molecules to DNA and Their Application in DNA Nanotechnology

    DEFF Research Database (Denmark)

    Olsen, Eva Maria

    2012-01-01

    Denne PhD afhandling præsenterer fire kapitler, som omhandler det videnskabelige område DNA nanoteknologi. Kapitel 1 er en general introduktion til DNA nanoteknologi, som først beskriver opbygningen af DNA og efter flere underkapitler slutter med en gennemgang af nogle fantastiske dynamiske DNA s...

  3. Efficient synthetic methods for the installation of boron-nitrogen bonds in conjugated organic molecules.

    Science.gov (United States)

    Morgan, Matthew M; Piers, Warren E

    2016-04-14

    Polycyclic aromatic hydrocarbons in which one or more CC units have been replaced by isoelectronic BN units have attracted interest as potentially improved organic materials in various devices. This promise has been hampered by a lack of access to gram quantities of these materials. However, the exploitation of keystone reactions such as ring closing metathesis, borylative cyclization of amino styrenes and electrophilic borylation has lead to strategies for access to workable amounts of material. These strategies can be augmented by judicious postfunctionalization reactions to diversify the library of materials available. This Frontier article highlights some of the recent successes and shows that the long promised applications of BN-doped PAHs are beginning to be explored in a meaningful way.

  4. Electrochemical Control of Single-Molecule Conductance by Fermi- Level Tuning and Conjugation Switching

    DEFF Research Database (Denmark)

    Baghernejad, Masoud; Zhao, Xiaotao; Ørnsø, Kristian Baruël

    2014-01-01

    ) centers, over >1 order of magnitude. For electrode potentials outside the redox-active region, the effect of the gate is simply to shift the molecular energy levels relative to the metal Fermi level. At the redox potential, the conductance changes abruptly as the AQ unit is oxidized...

  5. Photonic Molecule Lasers Revisited

    Science.gov (United States)

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.

    2014-05-01

    Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

  6. Interstellar molecules and masers

    International Nuclear Information System (INIS)

    Nguyen-Q-Rieu; Guibert, J.

    1978-01-01

    The study of dense and dark clouds, in which hydrogen is mostly in molecular form, became possible since the discovery of interstellar molecules, emitting in the centimeter and millimeter wavelengths. The molecular lines are generally not in local thermal equilibrium (LTE). Their intensity can often be explained by invoking a population inversion mechanism. Maser emission lines due to OH, H 2 O and SiO molecules are among the most intense molecular lines. The H 2 CO molecule, detected in absorption in front of the cold cosmic background radiation of 2.7 K, illustrates the inverse phenomenon, the antimaser absorption. For a radio transition of frequency v, the inversion rate Δn (relative population difference between the upper and lower level) as well as the maser gain can be determined from the radio observations. In the case of the OH lines in the 2 PIsub(3/2), J=3/2 state, the inversion rates approximately 1 to 2% derived from the observations, are comparable with those obtained in the laboratory. The determination of the excitation mechanisms of the masers, through the statistical equilibrium and radiative transfer equations, implies the knowledge of collisional and radiative transition probabilities. A pumping model, which can satisfactorily explain the radio observations of some interstellar OH clouds, will be discussed [fr

  7. The design and fabrication of supramolecular semiconductor nanowires formed by benzothienobenzothiophene (BTBT)-conjugated peptides.

    Science.gov (United States)

    Khalily, Mohammad Aref; Usta, Hakan; Ozdemir, Mehmet; Bakan, Gokhan; Dikecoglu, F Begum; Edwards-Gayle, Charlotte; Hutchinson, Jessica A; Hamley, Ian W; Dana, Aykutlu; Guler, Mustafa O

    2018-05-18

    π-Conjugated small molecules based on a [1]benzothieno[3,2-b]benzothiophene (BTBT) unit are of great research interest in the development of solution-processable semiconducting materials owing to their excellent charge-transport characteristics. However, the BTBT π-core has yet to be demonstrated in the form of electro-active one-dimensional (1D) nanowires that are self-assembled in aqueous media for potential use in bioelectronics and tissue engineering. Here we report the design, synthesis, and self-assembly of benzothienobenzothiophene (BTBT)-peptide conjugates, the BTBT-peptide (BTBT-C3-COHN-Ahx-VVAGKK-Am) and the C8-BTBT-peptide (C8-BTBT-C3-COHN-Ahx-VVAGKK-Am), as β-sheet forming amphiphilic molecules, which self-assemble into highly uniform nanofibers in water with diameters of 11-13(±1) nm and micron-size lengths. Spectroscopic characterization studies demonstrate the J-type π-π interactions among the BTBT molecules within the hydrophobic core of the self-assembled nanofibers yielding an electrical conductivity as high as 6.0 × 10-6 S cm-1. The BTBT π-core is demonstrated, for the first time, in the formation of self-assembled peptide 1D nanostructures in aqueous media for potential use in tissue engineering, bioelectronics and (opto)electronics. The conductivity achieved here is one of the highest reported to date in a non-doped state.

  8. Ligand-protein conjugated quantification assay by UV spectrophotometry in 99mTc indirect labeling

    International Nuclear Information System (INIS)

    Basualdo, Daniel A.; Rabiller, Graciela; Poch, Carolina; El Tamer, Elias A.

    2009-01-01

    Objective: Quantify IgG-HYNIC conjugated for obtaining substitution ratio and as a chemical quality control for 99m Tc labeling of this immunoglobulin. Introduction: The Operational Guidance on Hospital Radiopharmacy by IAEA states that the procedures performed in a Radiopharmacy Laboratory fall into three operational levels. At present, Nuclear Medicine Centre of 'Hospital de Clinicas' has an operational level 2b which requires the preparation of radiopharmaceuticals from approved reagent kits and radionuclide generators, and labeling of autologous blood cells. Centre's goal is to reach an operational level 3a, which allows us to compounding radiopharmaceuticals from drugs and radionuclides for diagnosis; modification to existing commercial kits; related research and development. In approach of that goal, we addressed the optimization of conjugation of proteins and peptides with S-HYNIC so as to bring about the procedures involved. In this work, was conjugated nonspecific polyclonal immunoglobulin G (IgG) with S-HYNIC. Our interest was focused in calculate how many HYNIC groups were incorporated per IgG molecule so that in later stages can be obtained a correlate with labeling efficiency. Materials and methods: A sample of IgG-HYNIC conjugate of 0.2 ml was diluted in 4 ml of benzaldehyde o-sulfonic acid (1 mg / ml, 0.1 M NaAc, pH 4.7). The reaction was incubated at room temperature overnight in darkness. As a negative control took 0.2 ml of IgG-HYNIC conjugate in 4 ml of NaAc buffer 0.1 M. 3 ml of benzaldehyde o-sulfonic acid (1 mg / ml 0.1 M NaAc, pH 4.7) was used as blank. The absorption of the hydrazone was read at 343 nm. The hydrazine concentration was calculated using a molar extinction coefficient ε (343 nm) 17000 M-1cm-1. Results: Molar substitution ratio (MSR) was calculated. The MSR indicates the number of HYNIC groups incorporated in the IgG-HYNIC conjugate determined by the spectrophotometric assay. Conclusions: In labeling with a bifunctional

  9. A smart magnetic resonance imaging contrast agent responsive to adenosine based on a DNA aptamer-conjugated gadolinium complex.

    Science.gov (United States)

    Xu, Weichen; Lu, Yi

    2011-05-07

    We report a general strategy for developing a smart MRI contrast agent for the sensing of small molecules such as adenosine based on a DNA aptamer that is conjugated to a Gd compound and a protein streptavidin. The binding of adenosine to its aptamer results in the dissociation of the Gd compound from the large protein, leading to decreases in the rotational correlation time and thus change of MRI contrast. © The Royal Society of Chemistry 2011

  10. The chemistry of bisallenes

    Directory of Open Access Journals (Sweden)

    Henning Hopf

    2012-11-01

    Full Text Available This review describes the preparation, structural properties and the use of bisallenes in organic synthesis for the first time. All classes of compounds containing at least two allene moieties are considered, starting from simple conjugated bisallenes and ending with allenes in which the two cumulenic units are connected by complex polycyclic ring systems, heteroatoms and/or heteroatom-containing tethers. Preparatively the bisallenes are especially useful in isomerization and cycloaddition reactions of all kinds leading to the respective target molecules with high atom economy and often in high yield. Bisallenes are hence substrates for generating molecular complexity in a small number of steps (high step economy.

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

    International Nuclear Information System (INIS)

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

    1985-01-01

    Several possibilities for plasma diagnostics provided by optical phase conjugation and, in particular, self-pumped phase conjugation in barium titanate (BaTiO 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

  12. Electrical Matching at Metal/Molecule Contacts for Efficient Heterogeneous Charge Transfer.

    Science.gov (United States)

    Sato, Shino; Iwase, Shigeru; Namba, Kotaro; Ono, Tomoya; Hara, Kenji; Fukuoka, Atsushi; Uosaki, Kohei; Ikeda, Katsuyoshi

    2018-02-27

    In a metal/molecule hybrid system, unavoidable electrical mismatch exists between metal continuum states and frontier molecular orbitals. This causes energy loss in the electron conduction across the metal/molecule interface. For efficient use of energy in a metal/molecule hybrid system, it is necessary to control interfacial electronic structures. Here we demonstrate that electrical matching between a gold substrate and π-conjugated molecular wires can be obtained by using monatomic foreign metal interlayers, which can change the degree of d-π* back-donation at metal/anchor contacts. This interfacial control leads to energy level alignment between the Fermi level of the metal electrode and conduction molecular orbitals, resulting in resonant electron conduction in the metal/molecule hybrid system. When this method is applied to molecule-modified electrocatalysts, the heterogeneous electrochemical reaction rate is considerably improved with significant suppression of energy loss at the internal electron conduction.

  13. Probing Surface-Adlayer Conjugation on Organic-Modified Si(111) Surfaces with Microscopy, Scattering, Spectroscopy, and Density Functional Theory

    International Nuclear Information System (INIS)

    Kellar, Joshua A.; Lin, Jui-Ching; Kim, Jun-Hyun; Yoder, Nathan L.; Bevan, Kirk H.; Stokes, Grace Y.; Geiger, Franz M.; Nguyen, SonBinh T.; Bedzyk, Michael J.; Hersam, Mark C.

    2009-01-01

    Highly conjugated molecules bound to silicon are promising candidates for organosilicon electronic devices and sensors. In this study, 1-bromo-4-ethynylbenzene was synthesized and reacted with a hydrogen-passivated Si(111) surface via ultraviolet irradiation. Through an array of characterization and modeling tools, the binding configuration and morphology of the reacted molecule were thoroughly analyzed. Atomic force microscopy confirmed an atomically flat surface morphology following reaction, while X-ray photoelectron spectroscopy verified reaction to the surface via the terminal alkyne moiety. In addition, synchrotron X-ray characterization, including X-ray reflectivity, X-ray fluorescence, and X-ray standing wave measurements, enabled sub-angstrom determination of the position of the bromine atom with respect to the silicon lattice. This structural characterization was quantitatively compared with density functional theory (DFT) calculations, thus enabling the π-conjugation of the terminal carbon atoms to be deduced. The X-ray and DFT results were additionally corroborated with the vibrational spectrum of the organic adlayer, which was measured with sum frequency generation. Overall, these results illustrate that the terminal carbon atoms in 1-bromo-4-ethynylbenzene adlayers on Si(111) retain π-conjugation, thus revealing alkyne molecules as promising candidates for organosilicon electronics and sensing.

  14. Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

    Directory of Open Access Journals (Sweden)

    Lucie Brulíková

    2016-09-01

    Full Text Available The hetero-Diels–Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds.

  15. Stereo- and regioselectivity of the hetero-Diels-Alder reaction of nitroso derivatives with conjugated dienes.

    Science.gov (United States)

    Brulíková, Lucie; Harrison, Aidan; Miller, Marvin J; Hlaváč, Jan

    2016-01-01

    The hetero-Diels-Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2 H -1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds.

  16. Direct calculation of self-consistent π bond orders in conjugated systems and pairing relations

    International Nuclear Information System (INIS)

    Castro, A.F.

    1982-01-01

    Pairing relations in excited states of conjugated systems which satisfy to a given symmetry with a Pariser-Parr-Pople-like (PPP) calculation are studied. Six π - electron systems are considered having a symmetry axis which does not cross π centers following a treatment which permits the direct obtainment of the bond order matrix based on Hall's method. Pairing relations are looked for, too, using particular solutions when U(3) groups is applied. Pyridazine molecules are used in order to test the results. (L.C.) [pt

  17. Quark chemistry: charmonium molecules

    International Nuclear Information System (INIS)

    De Rujula, A.; Jaffe, R.L.

    1977-01-01

    The theoretical and experimental evidence for two quark-two antiquark hadrons is reviewed. Concentration is placed on predictions for S-wave ''charmonium molecules,'' built of a c anti c charmonium pair and a light quark-antiquark pair. Their spectrum and quantum numbers are predicted and an estimate of their decay couplings and their prediction in monochromatic pion decays from charmonium resonances produced in e + e - -annihilation is given. Some S-wave charmonium resonances should be detectable in these decays, but typical branching ratios are only at the 1% level. 19 references

  18. Stochastic Spectral and Conjugate Descent Methods

    KAUST Repository

    Kovalev, Dmitry

    2018-02-11

    The state-of-the-art methods for solving optimization problems in big dimensions are variants of randomized coordinate descent (RCD). In this paper we introduce a fundamentally new type of acceleration strategy for RCD based on the augmentation of the set of coordinate directions by a few spectral or conjugate directions. As we increase the number of extra directions to be sampled from, the rate of the method improves, and interpolates between the linear rate of RCD and a linear rate independent of the condition number. We develop and analyze also inexact variants of these methods where the spectral and conjugate directions are allowed to be approximate only. We motivate the above development by proving several negative results which highlight the limitations of RCD with importance sampling.

  19. Stochastic Spectral and Conjugate Descent Methods

    KAUST Repository

    Kovalev, Dmitry; Gorbunov, Eduard; Gasanov, Elnur; Richtarik, Peter

    2018-01-01

    The state-of-the-art methods for solving optimization problems in big dimensions are variants of randomized coordinate descent (RCD). In this paper we introduce a fundamentally new type of acceleration strategy for RCD based on the augmentation of the set of coordinate directions by a few spectral or conjugate directions. As we increase the number of extra directions to be sampled from, the rate of the method improves, and interpolates between the linear rate of RCD and a linear rate independent of the condition number. We develop and analyze also inexact variants of these methods where the spectral and conjugate directions are allowed to be approximate only. We motivate the above development by proving several negative results which highlight the limitations of RCD with importance sampling.

  20. Phase-conjugate optical coherence tomography

    International Nuclear Information System (INIS)

    Erkmen, Baris I.; Shapiro, Jeffrey H.

    2006-01-01

    Quantum optical coherence tomography (Q-OCT) offers a factor-of-2 improvement in axial resolution and the advantage of even-order dispersion cancellation when it is compared to conventional OCT (C-OCT). These features have been ascribed to the nonclassical nature of the biphoton state employed in the former, as opposed to the classical state used in the latter. Phase-conjugate OCT (PC-OCT) shows that nonclassical light is not necessary to reap Q-OCT's advantages. PC-OCT uses classical-state signal and reference beams, which have a phase-sensitive cross correlation, together with phase conjugation to achieve the axial resolution and even-order dispersion cancellation of Q-OCT with a signal-to-noise ratio that can be comparable to that of C-OCT

  1. Antibody conjugate radioimmunotherapy of superficial bladder cancer

    International Nuclear Information System (INIS)

    Perkins, Alan; Hopper, Melanie; Murray, Andrea; Frier, Malcolm; Bishop, Mike

    2002-01-01

    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 C 595 (gG3) which reacts with the MUC1 glycoprotein antigen that is aberrantly expressed in a high proportion of bladder tumours. Radio immuno conjugates of the C 595 antibody have been produced with high radiolabelling efficiency and immuno reactivity using Tc-99 m 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. (author)

  2. Surface and Electrical Characterization of Conjugated Molecular Wires

    Science.gov (United States)

    Demissie, Abel Tesfahun

    This thesis describes the surface and electrical characterization of ultrathin organic films and interfaces. These films were synthesized on the surface of gold by utilizing layer by layer synthesis via imine condensation. Film growth by imine click (condensation) chemistry is particularly useful for molecular electronics experiments because it provides a convenient means to obtain and extend ?-conjugation in the growth direction. However, in the context of film growth from a solid substrate, the reaction yield per step has not been characterized previously, though it is critically important. To address these issues, my research focused on a comprehensive characterization of oligophenyleneimine (OPI) wires via Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), reflection-absorption infrared spectroscopy (RAIRS), and cyclic voltammetry (CV). In addition, we had the unique opportunity of developing the first of its kind implementation of nuclear reaction analysis (NRA) to probe the intensity of carbon atoms after each addition step. Overall the combination of various techniques indicated that film growth proceeds in a quantitative manner. Furthermore, the NRA experiment was optimized to measure the carbon content in self-assembled monolayers of alkyl thiols. The results indicated well-resolved coverage values for ultrathin films with consecutive steps of 2 carbon atoms per molecule. Another fundamental problem in molecular electronics is the vast discrepancy in the values of measured resistance per molecule between small and large area molecular junctions. In collaboration with researchers at the National University of Singapore, we addressed these issues by comparing the electrical properties of OPI wires with the eutectic gallium indium alloy (EGaIn) junction (1000 mum2), and conducting probe atomic force microscopy (CP-AFM) junction (50 nm2). Our results showed that intensive (i.e., area

  3. Ultra-cold molecule production

    International Nuclear Information System (INIS)

    Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

    2005-01-01

    The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled

  4. Charge conjugation invariance of the spectator equations

    International Nuclear Information System (INIS)

    Gross, F.

    1999-01-01

    In response to recent criticism, the authors show how to define the spectator equations for negative energies so that charge conjugation invariance is preserved. The result, which emerges naturally from the application of spectator principles to systems of particles with negative energies, is to replace all factors of the external energies W iota by √ W 2 iota , insuring that the amplitudes are independent of the sign of the energies W iota

  5. 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.

  6. Error Estimation in Preconditioned Conjugate Gradients

    Czech Academy of Sciences Publication Activity Database

    Strakoš, Zdeněk; Tichý, Petr

    2005-01-01

    Roč. 45, - (2005), s. 789-817 ISSN 0006-3835 R&D Projects: GA AV ČR 1ET400300415; GA AV ČR KJB1030306 Institutional research plan: CEZ:AV0Z10300504 Keywords : preconditioned conjugate gradient method * error bounds * stopping criteria * evaluation of convergence * numerical stability * finite precision arithmetic * rounding errors Subject RIV: BA - General Mathematics Impact factor: 0.509, year: 2005

  7. Conjugate gradient optimization programs for shuttle reentry

    Science.gov (United States)

    Powers, W. F.; Jacobson, R. A.; Leonard, D. A.

    1972-01-01

    Two computer programs for shuttle reentry trajectory optimization are listed and described. Both programs use the conjugate gradient method as the optimization procedure. The Phase 1 Program is developed in cartesian coordinates for a rotating spherical earth, and crossrange, downrange, maximum deceleration, total heating, and terminal speed, altitude, and flight path angle are included in the performance index. The programs make extensive use of subroutines so that they may be easily adapted to other atmospheric trajectory optimization problems.

  8. M-step preconditioned conjugate gradient methods

    Science.gov (United States)

    Adams, L.

    1983-01-01

    Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included.

  9. Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates

    International Nuclear Information System (INIS)

    Paul, Manidipa; Pal, Nabanita; Bhaumik, Asim

    2012-01-01

    Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6–7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate–adsorbent interaction at the surfaces. - Graphical abstract: Highly ordered 2D-hexagonal mesoporous borosilicate materials have been synthesized by using Pluronic P123 as template. The materials show very good adsorption and release of organic cationic dye molecules under physiological conditions. Highlights: ► Highly ordered 2D-hexagonal mesoporous borosilicate. ► Nonionic Pluoronic P123 templated mesoporous material. ► Adsorption of organic dyes at the mesopore surface. ► Controlled release of dyes under physiological pH and temperature. ► Release of safranine T (ST) and malachite green (MG) dyes in simulated body fluids.

  10. [Relationship between family variables and conjugal adjustment].

    Science.gov (United States)

    Jiménez-Picón, Nerea; Lima-Rodríguez, Joaquín-Salvador; Lima-Serrano, Marta

    2018-04-01

    To determine whether family variables, such as type of relationship, years of marriage, existence of offspring, number of members of family, stage of family life cycle, transition between stages, perceived social support, and/or stressful life events are related to conjugal adjustment. A cross-sectional and correlational study using questionnaires. Primary care and hospital units of selected centres in the province of Seville, Spain. Consecutive stratified sampling by quotas of 369 heterosexual couples over 18years of age, who maintained a relationship, with or without children, living in Seville. A self-report questionnaire for the sociodemographic variables, and the abbreviated version of the Dyadic Adjustment Scale, Questionnaire MOS Perceived Social Support, and Social Readjustment Rating Scale, were used. Descriptive and inferential statistics were performed with correlation analysis and multivariate regression. Statistically significant associations were found between conjugal adjustment and marriage years (r=-10: Pfamily life cycle (F=2.65; Pfamily life cycle stage (mature-aged stage) on conjugal adjustment (R2=.21; F=9.9; df=356; Prelationship. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  11. 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.

  12. Passing Current through Touching Molecules

    DEFF Research Database (Denmark)

    Schull, G.; Frederiksen, Thomas; Brandbyge, Mads

    2009-01-01

    The charge flow from a single C-60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two...

  13. Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

    Directory of Open Access Journals (Sweden)

    Igor V. Alabugin

    2011-06-01

    Full Text Available Hybrid molecules combining photoactivated aryl acetylenes and a dicationic lysine moiety cause the most efficient double-strand (ds DNA cleavage known to date for a small molecule. In order to test the connection between the alkylating ability and the DNA-damaging properties of these compounds, we investigated the photoreactivity of three isomeric aryl–tetrafluoropyridinyl (TFP alkynes with amide substituents in different positions (o-, m-, and p- toward a model π-system. Reactions with 1,4-cyclohexadiene (1,4-CHD were used to probe the alkylating properties of the triplet excited states in these three isomers whilst Stern–Volmer quenching experiments were used to investigate the kinetics of photoinduced electron transfer (PET. The three analogous isomeric lysine conjugates cleaved DNA with different efficiencies (34, 15, and 0% of ds DNA cleavage for p-, m-, and o-substituted lysine conjugates, respectively consistent with the alkylating ability of the respective acetamides. The significant protecting effect of the hydroxyl radical and singlet oxygen scavengers to DNA cleavage was shown only with m-lysine conjugate. All three isomeric lysine conjugates inhibited human melanoma cell growth under photoactivation: The p-conjugate had the lowest CC50 (50% cell cytotoxicity value of 1.49 × 10−7 M.

  14. Cathepsin B Cleavage of vcMMAE-Based Antibody-Drug Conjugate Is Not Drug Location or Monoclonal Antibody Carrier Specific.

    Science.gov (United States)

    Gikanga, Benson; Adeniji, Nia S; Patapoff, Thomas W; Chih, Hung-Wei; Yi, Li

    2016-04-20

    Antibody-drug conjugates (ADCs) require thorough characterization and understanding of product quality attributes. The framework of many ADCs comprises one molecule of antibody that is usually conjugated with multiple drug molecules at various locations. It is unknown whether the drug release rate from the ADC is dependent on drug location, and/or local environment, dictated by the sequence and structure of the antibody carrier. This study addresses these issues with valine-citrulline-monomethylauristatin E (vc-MMAE)-based ADC molecules conjugated at reduced disulfide bonds, by evaluating the cathepsin B catalyzed drug release rate of ADC molecules with different drug distributions or antibody carriers. MMAE drug release rates at different locations on ADC I were compared to evaluate the impact of drug location. No difference in rates was observed for drug released from the V(H), V(L), or C(H)2 domains of ADC I. Furthermore, four vc-MMAE ADC molecules were chosen as substrates for cathepsin B for evaluation of Michaelis-Menten parameters. There was no significant difference in K(M) or k(cat) values, suggesting that different sequences of the antibody carrier do not result in different drug release rates. Comparison between ADCs and small molecules containing vc-MMAE moieties as substrates for cathepsin B suggests that the presence of IgG1 antibody carrier, regardless of its bulkiness, does not impact drug release rate. Finally, a molecular dynamics simulation on ADC II revealed that the val-cit moiety at each of the eight possible conjugation sites was, on average, solvent accessible over 50% of its maximum solvent accessible surface area (SASA) during a 500 ns trajectory. Combined, these results suggest that the cathepsin cleavage sites for conjugated drugs are exposed enough for the enzyme to access and that the drug release rate is rather independent of drug location or monoclonal antibody carrier. Therefore, the distribution of drug conjugation at different

  15. Structure and optical bandgap relationship of π-conjugated systems.

    Directory of Open Access Journals (Sweden)

    André Leitão Botelho

    Full Text Available In bulk heterojunction photovoltaic systems both the open-circuit voltage as well as the short-circuit current, and hence the power conversion efficiency, are dependent on the optical bandgap of the electron-donor material. While first-principles methods are computationally intensive, simpler model Hamiltonian approaches typically suffer from one or more flaws: inability to optimize the geometries for their own input; absence of general, transferable parameters; and poor performance for non-planar systems. We introduce a set of new and revised parameters for the adapted Su-Schrieffer-Heeger (aSSH Hamiltonian, which is capable of optimizing geometries, along with rules for applying them to any [Formula: see text]-conjugated system containing C, N, O, or S, including non-planar systems. The predicted optical bandgaps show excellent agreement to UV-vis spectroscopy data points from literature, with a coefficient of determination [Formula: see text], a mean error of -0.05 eV, and a mean absolute deviation of 0.16 eV. We use the model to gain insights from PEDOT, fused thiophene polymers, poly-isothianaphthene, copolymers, and pentacene as sources of design rules in the search for low bandgap materials. Using the model as an in-silico design tool, a copolymer of benzodithiophenes along with a small-molecule derivative of pentacene are proposed as optimal donor materials for organic photovoltaics.

  16. Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells

    Science.gov (United States)

    Mauzeroll, Janine; Bard, Allen J.

    2004-01-01

    The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-μm-diameter electrode situated 10 μm from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster. PMID:15148374

  17. Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

    Directory of Open Access Journals (Sweden)

    Artur Jabłoński

    2017-11-01

    Full Text Available Fluorescent pyrene–linker–nucleobase (nucleobase = thymine, adenine conjugates with carbonyl and hydroxy functionalities in the linker were synthesized and characterized. X-ray single-crystal structure analysis performed for the pyrene–C(OCH2CH2–thymine (2 conjugate reveals dimers of molecules 2 stabilized by hydrogen bonds between the thymine moieties. The photochemical characterization showed structure-dependent fluorescence properties of the investigated compounds. The conjugates bearing a carbonyl function represent weak emitters as compared to compounds with a hydroxy function in the linker. The self-assembly properties of pyrene nucleobases were investigated in respect to their binding to single and double strand oligonucleotides in water and in buffer solution. In respect to the complementary oligothymidine T10 template in water, compounds 3 and 5 both show a self-assembling behavior according to canonical base–base pairing. However, in buffer solution, derivative 5 was much more effective than 3 in binding to the T10 template. Furthermore the adenine derivative 5 binds to the double-stranded (dA10–T10 template with a self-assembly ratio of 112%. Such a high value of a self-assembly ratio can be rationalized by a triple-helix-like binding, intercalation, or a mixture of both. Remarkably, compound 5 also shows dual staining pattern in living HeLa cells. Confocal microscopy confirmed that 5 predominantly stains mitochondria but it also accumulates in the nucleoli of the cells.

  18. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    International Nuclear Information System (INIS)

    Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

    2015-01-01

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe 3 O 4 @Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe 3 O 4 @Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe 3 O 4 @Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe 3 O 4 @Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe 3 O 4 @Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe 3 O 4 @Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

  19. Synthesis of novel bifunctional chelators and their use in preparing monoclonal antibody conjugates for tumor targeting

    International Nuclear Information System (INIS)

    Westerberg, D.A.; Carney, P.L.; Rogers, P.E.; Kline, S.J.; Johnson, D.K.

    1989-01-01

    Bifunctional derivatives of the chelating agents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, in which a p-isothiocyanatobenzyl moiety is attached at the methylene carbon atom of one carboxymethyl arm, was synthesized by reductive alkylation of the relevant polyamine with (p-nitrophenyl)pyruvic acid followed by carboxymethylation, reduction of the nitro group, and reaction with thiophosgene. The resulting isothiocyanate derivatives reacted with monoclonal antibody B72.3 to give antibody-chelator conjugates containing 3 mol of chelator per mole of immunoglobulin, without significant loss of immunological activity. Such conjugates, labeled with the radioisotopic metal indium-111, selectively bound a human colorectal carcinoma implanted in nude mice when given intravenously. Uptake into normal tissues was comparable to or lower than that reported for analogous conjugates with known bifunctional chelators. It is concluded that substitution with a protein reactive group at this position in polyaminopolycarboxylate chelators does not alter the chelating properties of these molecules to a sufficient extent to adversely affect biodistribution and thus provides a general method for the synthesis of such chelators

  20. Relationships for electron-vibrational coupling in conjugated π organic systems

    Science.gov (United States)

    O'Neill, L.; Lynch, P.; McNamara, M.; Byrne, H. J.

    2005-06-01

    A series of π conjugated systems were studied by absorption, photoluminescence and vibrational spectroscopy. As is common for these systems, a linear relationship between the positioning of the absorption and photoluminescence maxima plotted against inverse conjugation length is observed. The relationships are in good agreement with the simple particle in a box method, one of the earliest descriptions of the properties of one-dimensional organic molecules. In addition to the electronic transition energies, it was observed that the Stokes shift also exhibited a well-defined relationship with increasing conjugation length, implying a correlation between the electron-vibrational coupling and chain length. This correlation is further examined using Raman spectroscopy, whereby the integrated Raman scattering is seen to behave superlinearly with chain length. There is a clear indication that the vibrational activity and thus nonradiative decay processes are controllable through molecular structure. The correlations between the Stokes energies and the vibrational structure are also observed in a selection of PPV based polymers and a clear trend of increasing luminescence efficiency with decreasing vibrational activity and Stokes shift is observable. The implications of such structure property relationships in terms of materials design are discussed.

  1. Synthesis, Characterization, and Biodistribution of Quantum Dot-Celecoxib Conjugate in Mouse Paw Edema Model

    Directory of Open Access Journals (Sweden)

    Suresh K. Kalangi

    2018-01-01

    Full Text Available Increased risk of cardiovascular side effects has been reported with many of the drugs in the market, including nonsteroidal anti-inflammatory drugs (NSAIDs. Hence, it is critical to thoroughly evaluate the biodistribution and pharmacokinetic properties of the drugs. Presently nanotechnology in combination with noninvasive imaging techniques such as magnetic resonance imaging (MRI, computed axial tomography (CAT, and positron emission tomography (PET provides a better estimate of the spatio-temporal distribution of therapeutic molecules. Optical imaging using quantum dot- (QD- tagged biological macromolecules is emerging as a fast, economical, sensitive, and safer alternative for theranostic purposes. In the present study, we report the nanoconjugates of mercaptopropionic acid- (MPA- capped CdTe quantum dots (QDs and Celecoxib for bio-imaging in carrageenan-induced mouse paw edema model of inflammation. QD-Celecoxib conjugates were characterized by fluorescence, FT-IR, NMR, and zeta-potential studies. In vivo imaging of QD-Celecoxib conjugates showed clear localization in the inflamed tissue of mouse paw within 3 h, with a gradual increase reaching a maximum and a later decline. This decrease of fluorescence in the paw region is followed by an increase in urinary bladder region, suggesting the possible excretion of QD-drug conjugates from mice within 24 h.

  2. Synthesis and Studies of Sulfur-Containing Heterocyclic Molecules for Molecular Electronics

    DEFF Research Database (Denmark)

    Mazzanti, Virginia

    This work describes the synthesis and studies of sulfur containing π conjugated heterocycles, which are considered interesting motifs in the field of molecular electronics. The first project, which is covered in Chapter 1, concerns the functionalization of tetracycle dibenzo[bc,fg][1,4]dithiapent......This work describes the synthesis and studies of sulfur containing π conjugated heterocycles, which are considered interesting motifs in the field of molecular electronics. The first project, which is covered in Chapter 1, concerns the functionalization of tetracycle dibenzo[bc,fg][1......,4]dithiapentalene (DDP). Attempts to prepare the S-O analog are also discussed. Chapter 2, focuses upon the studies performed on DDP and other sulfur containing π conjugated organic molecules. Organic Field Effect Transistor devices were fabricated and their performances were evaluated. Chapter 3 entails...... the synthesis of dimeric structures of redox active system tetrathiafulvalene (TTF). Molecules with different conjugation pathways bridging two TTFs were synthesized and studied using CV and DPV in order to probe the electronic interaction between these two redox units. The last aspect of this thesis, which...

  3. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Swami, Rajan; Singh, Indu [National Institute of Pharmaceutical Education & Research (NIPER), Department of Pharmaceutics (India); Kulhari, Hitesh [CSIR-Indian Institute of Chemical Technology, Medicinal Chemistry & Pharmacology Division (India); Jeengar, Manish Kumar [National Institute of Pharmaceutical Education & Research (NIPER), Departmentof Pharmacology (India); Khan, Wahid, E-mail: wahid@niperhyd.ac.in; Sistla, Ramakrishna, E-mail: sistla@iict.res.in, E-mail: rksistla@yahoo.com [National Institute of Pharmaceutical Education & Research (NIPER), Department of Pharmaceutics (India)

    2015-06-15

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by {sup 1}HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere{sup ®}). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors.

  4. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    International Nuclear Information System (INIS)

    Swami, Rajan; Singh, Indu; Kulhari, Hitesh; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2015-01-01

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by 1 HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere ® ). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors

  5. p-Hydroxy benzoic acid-conjugated dendrimer nanotherapeutics as potential carriers for targeted drug delivery to brain: an in vitro and in vivo evaluation

    Science.gov (United States)

    Swami, Rajan; Singh, Indu; Kulhari, Hitesh; Jeengar, Manish Kumar; Khan, Wahid; Sistla, Ramakrishna

    2015-06-01

    Dendrimers which are discrete nanostructures/nanoparticles are emerging as promising candidates for many nanomedicine applications. Ligand-conjugated dendrimer facilitate the delivery of therapeutics in a targeted manner. Small molecules such as p-hydroxyl benzoic acid (pHBA) were found to have high affinity for sigma receptors which are prominent in most parts of central nervous system and tumors. The aim of this study was to synthesize pHBA-dendrimer conjugates as colloidal carrier for site-specific delivery of practically water insoluble drug, docetaxel (DTX) to brain tumors and to determine its targeting efficiency. pHBA, a small molecule ligand was coupled to the surface amine groups of generation 4-PAMAM dendrimer via a carbodiimide reaction and loaded with DTX. The conjugation was confirmed by 1HNMR and FT-IR spectroscopy. In vitro release of drug from DTX-loaded pHBA-conjugated dendrimer was found to be less as compared to unconjugated dendrimers. The prepared drug delivery system exhibited good physico-chemical stability and decrease in hemolytic toxicity. Cell viability and cell uptake studies were performed against U87MG human glioblastoma cells and formulations exerted considerable anticancer effect than plain drug. Conjugation of dendrimer with pHBA significantly enhanced the brain uptake of DTX which was shown by the recovery of a higher percentage of the dose from the brain following administration of pHBA-conjugated dendrimers compared with unconjugated dendrimer or formulation in clinical use (Taxotere®). Therefore, pHBA conjugated dendrimers could be an efficient delivery vehicle for the targeting of anticancer drugs to brain tumors.

  6. Mono(pyridine-N-oxide) DOTA analog and its G1/G4-PAMAM dendrimer conjugates labeled with 177Lu: Radiolabeling and biodistribution studies

    International Nuclear Information System (INIS)

    Laznickova, A.; Biricova, V.; Laznicek, M.; Hermann, P.

    2014-01-01

    177 Lu radiolabeling of the first (G1-) or fourth (G4-) generation polyaminoamide (PAMAM) dendrimer conjugates with DOTA-like bifunctional chelator with one methylenepyridine-N-oxide pendant arm (DO3A-py NO-C ) stability of the radiolabeled species and their pharmacokinetic characteristics were evaluated in preclinical experiments. The results showed that the G1- and G4-dendrimer conjugates, modified in average with 7.5 or 57 DO3A-py NO-C chelating units, respectively, can also be labeled with 177 Lu with a high specific activity and radiochemical purity even at 37 °C. The radiolabeled species were stable for at least 24 h. Distribution profile of G1-dendrimer conjugate in organs and tissues of rats was more favorable than that of G4 one. On the other hand, the later dendrimer conjugate bears a substantially higher number of metal chelators per molecule enabling binding of a considerably larger number of radiometals. Our results indicate that an employment of dendrimer-chelate conjugates with bound radiometals might represent a prospective way for radiolabeling of biologically active target-specific macromolecules to obtain markedly high specific activity. - Highlights: • Chelation of DOTA-like ligands suitable for biomacromolecules modification. • Radiolabeling of modified PAMAM-dendrimers with 177 Lu. • Determination of stability of the labeled conjugates. • Pharmacokinetic characteristics evaluated in preclinical experiments

  7. Up-converter nanophosphor Y2O2S:Er,Yb aminofunctionalized containing or not spherical silica conjugated with BSA

    International Nuclear Information System (INIS)

    Gelamos, Joao Paulo; Laranja, Marlon Larry; Alvino, Karla Cristina Lombardi; Camacho, Sabrina Alessio; Pires, Ana Maria

    2009-01-01

    This work reports on the study of the nanophosphor Y 2 O 2 S:Er(2%),Yb(1%) obtained from polymeric resin to be evaluated as fluorescent label with suitable features to conjugate with bio-molecules for bioassay up-converting phosphor technology (UPT) application. A conjugation protocol between bovine serum albumin (BSA) and the aminofunctionalized nanophosphor containing or not spherical silica was established. UV-vis results indicated an effective conjugation between nanophosphor particles and the protein. Up-conversion measurements under 980 nm excitation performed for samples before and after aminofunctionalization showed that nanophosphor particles luminescence features keep unchanged in all cases. All results suggest that the adapted protocol is feasible to provide a nanoparticle-protein effective conjugation preserving nanophosphor optical features. The presence of spherical silica can be considered advantageous to increase conjugation efficiency. Therefore, the developed procedure is applicable for future conjugations between the chosen nanophosphor and the streptavidin protein that takes part in the well known self-recognition system avidin-biotin.

  8. Enzymatic production of single-molecule FISH and RNA capture probes.

    Science.gov (United States)

    Gaspar, Imre; Wippich, Frank; Ephrussi, Anne

    2017-10-01

    Arrays of singly labeled short oligonucleotides that hybridize to a specific target revolutionized RNA biology, enabling quantitative, single-molecule microscopy analysis and high-efficiency RNA/RNP capture. Here, we describe a simple and efficient method that allows flexible functionalization of inexpensive DNA oligonucleotides by different fluorescent dyes or biotin using terminal deoxynucleotidyl transferase and custom-made functional group conjugated dideoxy-UTP. We show that (i) all steps of the oligonucleotide labeling-including conjugation, enzymatic synthesis, and product purification-can be performed in a standard biology laboratory, (ii) the process yields >90%, often >95% labeled product with minimal carryover of impurities, and (iii) the oligonucleotides can be labeled with different dyes or biotin, allowing single-molecule FISH, RNA affinity purification, and Northern blot analysis to be performed. © 2017 Gaspar et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  9. Lanthanide single molecule magnets

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jinkui; Zhang, Peng [Chinese Academy of Sciences, Changchun (China). Changchun Inst. of Applied Chemistry

    2015-10-01

    This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures - an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and explore new directions.

  10. Lanthanide single molecule magnets

    CERN Document Server

    Tang, Jinkui

    2015-01-01

    This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs, and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures – an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and...

  11. Molecules in the Spotlight

    Energy Technology Data Exchange (ETDEWEB)

    Cryan, James

    2010-01-26

    SLAC has just unveiled the world's first X-ray laser, the LCLS. This machine produces pulses of X-rays that are ten billion times brighter than those from conventional sources. One of the goals of this machine is to make movies of chemical reactions, including reactions necessary for life and reactions that might power new energy technologies. This public lecture will show the first results from the LCLS. As a first target, we have chosen nitrogen gas, the main component of the air we breathe. Using the unprecedented power of the LCLS X-rays as a blasting torch, we have created new forms of this molecule and with unique electronic arrangements. Please share with us the first insights from this new technology.

  12. Receptor-mediated photo-cytotoxicity: synthesis of a photoactivatable psoralen derivative conjugated to insulin.

    Science.gov (United States)

    Gasparro, F P; Knobler, R M; Yemul, S S; Bisaccia, E; Edelson, R L

    1986-12-15

    4'-Aminomethyl-4,5',8-trimethylpsoralen has been chemically conjugated to insulin using a carbodiimide derivative. The psoralen moiety retains its photochemical reactivity as evidenced by its ability to crosslink DNA after exposure to long wavelength ultraviolet light (UVA, 320-400 nm). This chimeric molecule has been used to selectively kill a population of lymphocytes whose expression of insulin receptors has been stimulated with phytohemagglutinin. Insulin carries the psoralen into the cell via receptor-mediated endocytosis, where it is subsequently activated by exposure to UVA light. The UVA induced activity of AMT-insulin can be blocked by the presence of native insulin. The viability of unstimulated lymphocytes was not affected by AMT-insulin and UVA light. The hybrid insulin-psoralen molecule may be a prototype for a family of phototoxic drugs which can be selectively delivered to subsets of lymphocytes.

  13. Self-assembling chimeric polypeptide-doxorubicin conjugate nanoparticles that abolish tumours after a single injection

    Science.gov (United States)

    Andrew Mackay, J.; Chen, Mingnan; McDaniel, Jonathan R.; Liu, Wenge; Simnick, Andrew J.; Chilkoti, Ashutosh

    2009-12-01

    New strategies to self-assemble biocompatible materials into nanoscale, drug-loaded packages with improved therapeutic efficacy are needed for nanomedicine. To address this need, we developed artificial recombinant chimeric polypeptides (CPs) that spontaneously self-assemble into sub-100-nm-sized, near-monodisperse nanoparticles on conjugation of diverse hydrophobic molecules, including chemotherapeutics. These CPs consist of a biodegradable polypeptide that is attached to a short Cys-rich segment. Covalent modification of the Cys residues with a structurally diverse set of hydrophobic small molecules, including chemotherapeutics, leads to spontaneous formation of nanoparticles over a range of CP compositions and molecular weights. When used to deliver chemotherapeutics to a murine cancer model, CP nanoparticles have a fourfold higher maximum tolerated dose than free drug, and induce nearly complete tumour regression after a single dose. This simple strategy can promote co-assembly of drugs, imaging agents and targeting moieties into multifunctional nanomedicines.

  14. Optical, Electrical and Magnetic Studies of Pi-Conjugated Organic Semiconductor Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vardeny, Zeev Valentine [Univ. of Utah, Salt Lake City, UT (United States)

    2016-09-15

    Over the duration of this grant our group has studied the transient and cw optical response of various π-conjugated polymers, oligomers, single crystals, fullerene molecules and blends of organic donor-acceptor molecules. We have been also involved in complementary experiments such as magneto-optical studies and spin-physics. We have advanced the field of photophysics of these materials by providing information on their excited state energies and primodal and long-lived photoexcitations such as singlet excitons, triplet excitons, polaron-pairs, excimers and exciplexes. We also fabricated various organic optoelectronic devices such as organic light emitting diodes (OLED), electrochemical cells, organic diodes, organic spin-valves (OSV), and organic photovoltaic (OPV) solar cells. These devices benefited the society in terms of cheap and energy saving illumination, as well as harnessing the solar energy.

  15. Molecular Polygons Probe the Role of Intramolecular Strain in the Photophysics of π-Conjugated Chromophores.

    Science.gov (United States)

    Wilhelm, Philipp; Vogelsang, Jan; Poluektov, Georgiy; Schönfelder, Nina; Keller, Tristan J; Jester, Stefan-Sven; Höger, Sigurd; Lupton, John M

    2017-01-24

    π-Conjugated segments, chromophores, are the electronically active units of polymer materials used in organic electronics. To elucidate the effect of the bending of these linear moieties on elementary electronic properties, such as luminescence color and radiative rate, we introduce a series of molecular polygons. The π-system in these molecules becomes so distorted in bichromophores (digons) that these absorb and emit light of arbitrary polarization: any part of the chain absorbs and emits radiation with equal probability. Bending leads to a cancellation of transition dipole moment (TDM), increasing excited-state lifetime. Simultaneously, fluorescence shifts to the red as radiative transitions require mixing of the excited state with vibrational modes. However, strain can become so large that excited-state localization on shorter units of the chain occurs, compensating TDM cancellation. The underlying correlations between shape and photophysics can only be resolved in single molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Optimization of photoactive protein Z for fast and efficient site-specific conjugation of native IgG.

    Science.gov (United States)

    Hui, James Z; Tsourkas, Andrew

    2014-09-17

    Antibody conjugates have been used in a variety of applications from immunoassays to drug conjugates. However, it is becoming increasingly clear that in order to maximize an antibody's antigen binding ability and to produce homogeneous antibody-conjugates, the conjugated molecule should be attached onto IgG site-specifically. We previously developed a facile method for the site-specific modification of full length, native IgGs by engineering a recombinant Protein Z that forms a covalent link to the Fc domain of IgG upon exposure to long wavelength UV light. To further improve the efficiency of Protein Z production and IgG conjugation, we constructed a panel of 13 different Protein Z variants with the UV-active amino acid benzoylphenylalanine (BPA) in different locations. By using this panel of Protein Z to cross-link a range of IgGs from different hosts, including human, mouse, and rat, we discovered two previously unknown Protein Z variants, L17BPA and K35BPA, that are capable of cross-linking many commonly used IgG isotypes with efficiencies ranging from 60% to 95% after only 1 h of UV exposure. When compared to existing site-specific methods, which often require cloning or enzymatic reactions, the Protein Z-based method described here, utilizing the L17BPA, K35BPA, and the previously described Q32BPA variants, represents a vastly more accessible and efficient approach that is compatible with nearly all native IgGs, thus making site-specific conjugation more accessible to the general research community.

  17. Synthesis, characterization and target protein binding of drug-conjugated quantum dots in vitro and in living cells

    International Nuclear Information System (INIS)

    Choi, Youngseon; Kim, Minjung; Cho, Yoojin; Yun, Eunsuk; Song, Rita

    2013-01-01

    Elucidation of unknown target proteins of a drug is of great importance in understanding cell biology and drug discovery. There have been extensive studies to discover and identify target proteins in the cell. Visualization of targets using drug-conjugated probes has been an important approach to gathering mechanistic information of drug action at the cellular level. As quantum dot (QD) nanocrystals have attracted much attention as a fluorescent probe in the bioimaging area, we prepared drug-conjugated QD to explore the potential of target discovery. As a model drug, we selected a well-known anticancer drug, methotrexate (MTX), which has been known to target dihydrofolate reductase (DHFR) with high affinity binding (K d = 0.54 nM). MTX molecules were covalently attached to amino-PEG-polymer-coated QDs. Specific interactions of MTX-conjugated QDs with DHFR were identified using agarose gel electrophoresis and fluorescence microscopy. Cellular uptake of the MTX-conjugated QDs in living CHO cells was investigated with regard to their localization and distribution pattern. MTX–QD was found to be internalized into the cells via caveolae-medicated endocytosis without significant sequestration in endosomes. A colocalization experiment of the MTX–QD conjugate with antiDHFR-TAT-QD also confirmed that MTX–QD binds to the target DHFR. This study showed the potential of the drug-QD conjugate to identify or visualize drug–target interactions in the cell, which is currently of great importance in the area of drug discovery and chemical biology. (paper)

  18. Magnetic field modification of ultracold molecule-molecule collisions

    International Nuclear Information System (INIS)

    Tscherbul, T V; Suleimanov, Yu V; Aquilanti, V; Krems, R V

    2009-01-01

    We present an accurate quantum mechanical study of molecule-molecule collisions in the presence of a magnetic field. The work focuses on the analysis of elastic scattering and spin relaxation in collisions of O 2 ( 3 Σ g - ) molecules at cold (∼0.1 K) and ultracold (∼10 -6 K) temperatures. Our calculations show that magnetic spin relaxation in molecule-molecule collisions is extremely efficient except at magnetic fields below 1 mT. The rate constant for spin relaxation at T=0.1 K and a magnetic field of 0.1 T is found to be as large as 6.1x10 -11 cm -3 s -1 . The magnetic field dependence of elastic and inelastic scattering cross sections at ultracold temperatures is dominated by a manifold of Feshbach resonances with the density of ∼100 resonances per Tesla for collisions of molecules in the absolute ground state. This suggests that the scattering length of ultracold molecules in the absolute ground state can be effectively tuned in a very wide range of magnetic fields. Our calculations demonstrate that the number and properties of the magnetic Feshbach resonances are dramatically different for molecules in the absolute ground and excited spin states. The density of Feshbach resonances for molecule-molecule scattering in the low-field-seeking Zeeman state is reduced by a factor of 10.

  19. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Palladium-Catalyzed Direct C-H Arylations of Dioxythiophenes Bearing Reactive Functional Groups: A Step-Economical Approach for Functional π-Conjugated Oligoarenes

    KAUST Repository

    Liu, Ching-Yuan

    2015-06-25

    A Pd-catalyzed and single-step C-H arylation of dioxythiophene derivates bearing unprotected reactive functional groups (-OH, -COOH, -N3) in a phosphine-free manner has been developed. Various dioxythiopene-based oligoarenes with extended π-conjugation are obtained with good yields (up to 90%). These oligoarenes display suitable optical properties (absorption and emission maxima, quantum yields) and contain reactive functional groups suitable for further conjugations with bioactive molecules. This new methodology is step economical (fewer synthetic steps), environmental friendly (no toxic metal-containing side-poducts) and the oligoarenes synthesized are potentially applicable for bio-labeling, bioimaging, and biosensing.

  1. Palladium-Catalyzed Direct C-H Arylations of Dioxythiophenes Bearing Reactive Functional Groups: A Step-Economical Approach for Functional π-Conjugated Oligoarenes

    KAUST Repository

    Liu, Ching-Yuan; Chong, Hui; Lin, Hsing-An; Yamashita, Yoshiro; Zheng, Bin; Huang, Kuo-Wei; Hashizume, Daisuke; Yu, Hsiao-hua

    2015-01-01

    A Pd-catalyzed and single-step C-H arylation of dioxythiophene derivates bearing unprotected reactive functional groups (-OH, -COOH, -N3) in a phosphine-free manner has been developed. Various dioxythiopene-based oligoarenes with extended π-conjugation are obtained with good yields (up to 90%). These oligoarenes display suitable optical properties (absorption and emission maxima, quantum yields) and contain reactive functional groups suitable for further conjugations with bioactive molecules. This new methodology is step economical (fewer synthetic steps), environmental friendly (no toxic metal-containing side-poducts) and the oligoarenes synthesized are potentially applicable for bio-labeling, bioimaging, and biosensing.

  2. Novel HPC-ibuprofen conjugates: synthesis, characterization, thermal analysis and degradation kinetics

    International Nuclear Information System (INIS)

    Hussain, M.A.; Lodhi, B.A.; Abbas, K.

    2014-01-01

    Naturally occurring hydrophilic polysaccharides are advantageously used as drug carriers because they provide a mechanism to improve drug action. Hydroxypropylcellulose (HPC) is water-soluble, biocompatible and bears hydroxyl groups for drug conjugation outside the parent polymeric chains. This unique geometry allows the attachment of drug molecules with higher covalent loading. The HPC-Ibuprofen conjugates as macromolecular prodrugs were therefore synthesized employing homogenous and one pot reaction methodologies using p-toluenesulfonyl chloride in N,N-dimethylacetamide solvent at 80 degree C for 24 h under nitrogen atmosphere. The imidazole was used as a base for neutralization of acidic impurities. Present strategy appeared effective to get high yield (77-81%) and high degree of drug substitution (DS 0.88-1.40) onto the HPC polymer as determined by the acid-base titration and verified by 1H-NMR spectroscopy. The gel permeation chromatography has shown uni-modal absorption which indicates no significant degradation of polymer during reaction. Macromolecular prodrugs with different DS of ibuprofen were synthesized, purified, characterized and found soluble in organic solvents. From thermogravimetric analysis, initial, maximum and final degradation temperatures of the conjugates were calculated and compared for relative thermal stability. Thermal degradation kinetics was also studied and results have indicated that degradation of conjugates follows about first order kinetics as calculated by Kissinger model. The energy of activation was also found moderate 92.38, 99.34 and 87.34 kJ/mol as calculated using Friedman, Broido and Chang models. It was found that these novel prodrugs of ibuprofen were thermally stable therefore these may have potential pharmaceutical applications. (author)

  3. Evaluation of Immunogenicity of Yersinia enterocolitica O:8 Oligopolysaccaride-DiphtheriaeToxoide Conjugate in Mice

    Directory of Open Access Journals (Sweden)

    SM Rezavian

    2015-06-01

    Full Text Available Background & objectives: Yersiniosis is created by Yersinia enterocolitica O:8 and causes problems in the world especialy in cold and mild countries. The purpose of this study is to evaluate the immunogenicity of Yersinia enterocolitica O:8 oligopolysaccaride (OPS conjugate to diphtheria toxoid (DT as a vaccine candidate.   Methods : After cultivation of bacteria, the LPS were isolated by modified hot phenol method. Then dialysis and concentration were done and the OPS were extracted by acetic acid 2%. To conjugate with diphtheria toxoid, ADH was used as a spacer molecule and EDAC as a linker. Conjugate was purified by gel filtration. Then 4 groups of female BALB/c mice were selected (15 mice in each group. Injection was performed intraperitoneally in three doses with two weeks interval. Then serum samples were collected and antibody response against OPS was measured by indirect ELISA method for detection of total IgG, IgA, IgM, IgG1, IgG2a, IgG2b and IgG3.   Results: After second and third doses, OPS-DT recieved group showed significant increase in all types of antibodies titer in anti-OPS in comparison to group that recived nonconjugated OPS. The increase in titer of antibodies was as: OPS-DT>OPS>DT. A remarkable increase was shown in total IgG and IgM titers (with total amount of 3204 and 670, respectively. In IgG1 subclass the amount was 920 and in other subclasses of IgG (IgG3, IgG2a and IgG2b the amounts were 910, 110, and 99, respectively.   Conclusion: The results shows that OPS of Yersinia enterocolitica O:8 increases the anti-OPS antibodies in the form of conjugate with diphtheria toxoid and could be considered as an appropriate vaccine candidate.

  4. Exploiting members of the BAHD acyltransferase family to synthesize multiple hydroxycinnamate and benzoate conjugates in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Eudes, Aymerick [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mouille, Maxence [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Robinson, David S. [Joint BioEnergy Institute, Emeryville, CA (United States); Benites, Veronica T. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); San Francisco State Univ., San Francisco, CA (United States); Wang, George [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Roux, Lucien [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Tsai, Yi-Lin [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baidoo, Edward E. K. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chiu, Tsan-Yu [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Heazlewood, Joshua L. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); The Univ. of Melbourne, Melbourne, VIC (Australia); Scheller, Henrik V. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mukhopadhyay, Aindrila [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Keasling, Jay D. [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Horsholm (Denmark); Deutsch, Samuel [Joint BioEnergy Institute, Emeryville, CA (United States); Loqué, Dominique [Joint BioEnergy Institute, Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. Claude Bernard Lyon 1, Villeurbanne (France)

    2016-11-21

    BAHD acyltransferases, named after the first four biochemically characterized enzymes of the group, are plant-specific enzymes that catalyze the transfer of coenzyme A-activated donors onto various acceptor molecules. They are responsible for the synthesis in plants of a myriad of secondary metabolites, some of which are beneficial for humans either as therapeutics or as specialty chemicals such as flavors and fragrances. The production of pharmaceutical, nutraceutical and commodity chemicals using engineered microbes is an alternative, green route to energy-intensive chemical syntheses that consume petroleum-based precursors. However, identification of appropriate enzymes and validation of their functional expression in heterologous hosts is a prerequisite for the design and implementation of metabolic pathways in microbes for the synthesis of such target chemicals. As a result, for the synthesis of valuable metabolites in the yeast Saccharomyces cerevisiae, we selected BAHD acyltransferases based on their preferred donor and acceptor substrates. In particular, BAHDs that use hydroxycinnamoyl-CoAs and/or benzoyl-CoA as donors were targeted because a large number of molecules beneficial to humans belong to this family of hydroxycinnamate and benzoate conjugates. The selected BAHD coding sequences were synthesized and cloned individually on a vector containing the Arabidopsis gene At4CL5, which encodes a promiscuous 4-coumarate:CoA ligase active on hydroxycinnamates and benzoates. The various S. cerevisiae strains obtained for co-expression of At4CL5 with the different BAHDs effectively produced a wide array of valuable hydroxycinnamate and benzoate conjugates upon addition of adequate combinations of donors and acceptor molecules. In particular, we report here for the first time the production in yeast of rosmarinic acid and its derivatives, quinate hydroxycinnamate esters such as chlorogenic acid, and glycerol hydroxycinnamate esters

  5. Single-Molecule Transport at a Rectifying GaAs Contact.

    Science.gov (United States)

    Vezzoli, Andrea; Brooke, Richard J; Ferri, Nicolò; Higgins, Simon J; Schwarzacher, Walther; Nichols, Richard J

    2017-02-08

    In most single- or few-molecule devices, the contact electrodes are simple ohmic resistors. Here we describe a new type of single-molecule device in which metal and semiconductor contact electrodes impart a function, namely, current rectification, which is then modified by a molecule bridging the gap. We study junctions with the structure Au STM tip/X/n-GaAs substrate, where "X" is either a simple alkanedithiol or a conjugated unit bearing thiol/methylthiol contacts, and we detect current jumps corresponding to the attachment and detachment of single molecules. From the magnitudes of the current jumps we can deduce values for the conductance decay constant with molecule length that agree well with values determined from Au/molecule/Au junctions. The ability to impart functionality to a single-molecule device through the properties of the contacts as well as through the properties of the molecule represents a significant extension of the single-molecule electronics "tool-box".

  6. Minimizing inner product data dependencies in conjugate gradient iteration

    Science.gov (United States)

    Vanrosendale, J.

    1983-01-01

    The amount of concurrency available in conjugate gradient iteration is limited by the summations required in the inner product computations. The inner product of two vectors of length N requires time c log(N), if N or more processors are available. This paper describes an algebraic restructuring of the conjugate gradient algorithm which minimizes data dependencies due to inner product calculations. After an initial start up, the new algorithm can perform a conjugate gradient iteration in time c*log(log(N)).

  7. The study of conjugation of anti-CD20 monoclonal antibody for labeling with metallic or lanthanides radionuclides

    International Nuclear Information System (INIS)

    Akanji, Akinkunmi Ganiyu

    2012-01-01

    Lymphomas are malignancies or cancers that start from the malign transformation of a lymphocyte in the lymphatic system. Generally, lymphomas start from the lymph nodes or from the agglomeration of the lymphatic tissues, organs like stomach, intestines, in some cases it can involve the bone marrow and the blood, it can also disseminate to other organs. Lymphomas are divided in two major categories: Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). Patient with NHL are generally treated with radiotherapy alone or combined with immunotherapy using monoclonal antibody rituximab (MabThera®). Currently, monoclonal antibodies (Acm) conjugated with bifunctional chelate agents and radiolabeled with metallic or lanthanides radionuclides are a treatment reality for patients with NHL by the principle of radioimmunotherapy (RIT). This study focused on the conditions of conjugation of Acm rituximab (MabThera®) with bifunctional chelating agents DOTA and DTPA. Various parameters were studied: method of Acm purification, conditions of Acm conjugation, the method for determination of number of chelate agent coupled to the Acm, method for purification of the conjugated antibody Acm, conditions of labeling of the conjugated antibody with lutetium-177, method of purification of the radiolabeled immuno conjugate, method of radiochemical purity (RP), specific binding in vitro Raji cells (Human Burkitt) and biological distribution performed in normal Balb-c mouse. The three methodologies employed in pre-purification of Acm (dialysis, size exclusion chromatograph and dial filtration) demonstrated to be efficient; they provided sample recovery exceeding 90%. However, the methodology of dial filtration presents minimal sample loss, and gave the final recovery of the sample in micro liters; thereby facilitating sample use in subsequent experiments. Numbers of chelators attached to the Acm molecule was proportional to the molar ratio studied. When we evaluated the influence of different

  8. Nanodiamond-chymotrypsin and nanodiamond-papain conjugates, their synthesis and activity and visualization of their interaction with cells using optical and electron microscopy.

    Science.gov (United States)

    Golyshev, Sergey A; Berkovich, Anna K; Yakovlev, Ruslan Yu; Bystrov, Dmitry M; Ivanov, Nikita M; Balandina, Galina N; Rudenskaya, Galina N

    2017-07-28

    Two novel conjugates of detonation nanodiamonds (dNDs) with the proteolytic enzymes chymotrypsin and papain were synthesized. The synthesis was performed via functionalization of the dNDs' surface with acidic/alkali treatment followed by carbodiimide-mediated protein binding. Covalent binding of the enzymes was confirmed by Fourier transform infrared spectrographic analysis and high-performance liquid chromatography (HPLC) amino acid analysis. HPLC also proved the preservation of the enzymes' composition during synthesis. The same assay was used to determine the binding ratios. The ratios were 12% (mass to mass) for chymotrypsin and 7.4% for papain. The enzymatic activity of the conjugates was measured using chromogenic substrates and appeared to be approximately 40% of that of the native enzymes. The optimum pH values and stability under various conditions were determined. The sizes of resulting particles were measured using dynamic light scattering and direct electron microscopic observation. The enzyme conjugates were shown to be prone to aggregation, resulting in micrometer-sized particles. The ζ-potentials were measured and found to be positive for the conjugates. The conjugated enzymes were tested for biological activity using an in vitro model of cultured transformed human epithelial cells (HeLa cell line). It was shown that dND-conjugated enzymes effectively bind to the surface of the cells and that enzymes attack exposed proteins on the plasma membrane, including cell adhesion molecules. Incubation with conjugated enzymes results in morphological changes of the cells but does not affect cell viability, as judged by monitoring the cell division index and conducting ultrastructural studies. dNDs are internalized by the cells via endocytosis, being enclosed in forming coated vesicles by chance, and they accumulate in single membrane-bound vacuoles, presumably late endosomes/phagosomes, along with multimembranous onionlike structures. The authors propose a

  9. Exciton Scattering approach for conjugated macromolecules: from electronic spectra to electron-phonon coupling

    Science.gov (United States)

    Tretiak, Sergei

    2014-03-01

    The exciton scattering (ES) technique is a multiscale approach developed for efficient calculations of excited-state electronic structure and optical spectra in low-dimensional conjugated macromolecules. Within the ES method, the electronic excitations in the molecular structure are attributed to standing waves representing quantum quasi-particles (excitons), which reside on the graph. The exciton propagation on the linear segments is characterized by the exciton dispersion, whereas the exciton scattering on the branching centers is determined by the energy-dependent scattering matrices. Using these ES energetic parameters, the excitation energies are then found by solving a set of generalized ``particle in a box'' problems on the graph that represents the molecule. All parameters can be extracted from quantum-chemical computations of small molecular fragments and tabulated in the ES library for further applications. Subsequently, spectroscopic modeling for any macrostructure within considered molecular family could be performed with negligible numerical effort. The exciton scattering properties of molecular vertices can be further described by tight-binding or equivalently lattice models. The on-site energies and hopping constants are obtained from the exciton dispersion and scattering matrices. Such tight-binding model approach is particularly useful to describe the exciton-phonon coupling, energetic disorder and incoherent energy transfer in large branched conjugated molecules. Overall the ES applications accurately reproduce the optical spectra compared to the reference quantum chemistry results, and make possible to predict spectra of complex macromolecules, where conventional electronic structure calculations are unfeasible.

  10. Development and preclinical characterisation of 99mTc-labelled Affibody molecules with reduced renal uptake

    International Nuclear Information System (INIS)

    Ekblad, Torun; Karlstroem, Amelie Eriksson; Tran, Thuy; Orlova, Anna; Feldwisch, Joachim; Widstroem, Charles; Abrahmsen, Lars; Wennborg, Anders; Tolmachev, Vladimir

    2008-01-01

    Affibody molecules are low molecular weight proteins (7 kDa), which can be selected to bind to tumour-associated target proteins with subnanomolar affinity. Because of rapid tumour localisation and clearance from nonspecific compartments, Affibody molecules are promising tracers for molecular imaging. Earlier, 99m Tc-labelled Affibody molecules demonstrated specific targeting of tumour xenografts. However, the biodistribution was suboptimal either because of hepatobiliary excretion or high renal uptake of the radioactivity. The goal of this study was to optimise the biodistribution of Affibody molecules by chelator engineering. Anti-HER2 Z HER2:342 Affibody molecules, carrying the mercaptoacetyl-glutamyl-seryl-glutamyl (maESE), mercaptoacetyl-glutamyl-glutamyl-seryl (maEES) and mercaptoacetyl-seryl-glutamyl-glutamyl (maSEE) chelators, were prepared by peptide synthesis and labelled with 99m Tc. The tumour-targeting capacity of these conjugates was compared with each other and with the best previously available conjugate, 99m Tc-maEEE-Z HER2:342, in nude mice bearing SKOV-3 xenografts. The tumour-targeting capacity of the most promising conjugate, 99m Tc-maESE-Z HER2:342, was compared with radioiodinated Z HER2:342 . All novel conjugates demonstrated successful tumour targeting and a low degree of hepatobiliary excretion. The renal uptakes of serine-containing conjugates, 33±5, 68±21 and 71±10%IA/g, for 99m Tc-maESE-Z HER2:342 , 99m Tc-maEES-Z HER2:342 and 99m Tc-maSEE-Z HER2:342 , respectively, were significantly reduced in comparison with 99m Tc-maEEE-Z HER2:342 (102 ± 13%IA/g). For 99m Tc-maESE-Z HER2:342 , a tumour uptake of 9.6±1.8%IA/g and a tumour-to-blood ratio of 58±6 were reached at 4 h p.i. A combination of serine and glutamic acid residues in the chelator sequence confers increased renal excretion and relatively low renal uptake of 99m Tc-labelled Affibody molecules. In combination with preserved targeting capacity, this improved imaging of targets

  11. Electron-excited molecule interactions

    International Nuclear Information System (INIS)

    Christophorou, L.G.; Tennessee Univ., Knoxville, TN

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

  12. Theory of optical transitions in conjugated polymers. I. Ideal systems.

    Science.gov (United States)

    Barford, William; Marcus, Max

    2014-10-28

    We describe a theory of linear optical transitions in conjugated polymers. The theory is based on three assumptions. The first is that the low-lying excited states of conjugated polymers are Frenkel excitons coupled to local normal modes, described by the Frenkel-Holstein model. Second, we assume that the relevant parameter regime is ℏω ≪ J, i.e., the adiabatic regime, and thus the Born-Oppenheimer factorization of the electronic and nuclear degrees of freedom is generally applicable. Finally, we assume that the Condon approximation is valid, i.e., the exciton-polaron wavefunction is essentially independent of the normal modes. Using these assumptions we derive an expression for an effective Huang-Rhys parameter for a chain (or chromophore) of N monomers, given by S(N) = S(1)/IPR, where S(1) is the Huang-Rhys parameter for an isolated monomer. IPR is the inverse participation ratio, defined by IPR = (∑(n)|Ψ(n)|(4))(-1), where Ψ(n) is the exciton center-of-mass wavefunction. Since the IPR is proportional to the spread of the exciton center-of-mass wavefunction, this is a key result, as it shows that S(N) decreases with chain length. As in molecules, in a polymer S(N) has two interpretations. First, ℏωS(N) is the relaxation energy of an excited state caused by its coupling to the normal modes. Second, S(N) appears in the definition of an effective Franck-Condon factor, F(0v)(N) = S(N)(v)exp ( - S(N))/v! for the vth vibronic manifold. We show that the 0 - 0 and 0 - 1 optical intensities are proportional to F00(N) and F01(N), respectively, and thus the ratio of the 0 - 1 to 0 - 0 absorption and emission intensities are proportional to S(N). These analytical results are checked by extensive DMRG calculations and found to be generally valid, particularly for emission. However, for large chain lengths higher-lying quasimomentum exciton states become degenerate with the lowest vibrational excitation of the lowest exciton state. When this happens there is

  13. Poly(2-oxazoline)-Antibiotic Conjugates with Penicillins.

    Science.gov (United States)

    Schmidt, Martin; Bast, Livia K; Lanfer, Franziska; Richter, Lena; Hennes, Elisabeth; Seymen, Rana; Krumm, Christian; Tiller, Joerg C

    2017-09-20

    The conjugation of antibiotics with polymers is rarely done, but it might be a promising alternative to low-molecular-weight derivatization. The two penicillins penicillin G (PenG) and penicillin V (PenV) were attached to the end groups of different water-soluble poly(2-oxazoline)s (POx) via their carboxylic acid function. This ester group was shown to be more stable against hydrolysis than the β-lactam ring of the penicillins. The conjugates are still antimicrobially active and up to 20 times more stable against penicillinase catalyzed hydrolysis. The antibiotic activity of the conjugates against Staphylococcus aureus in the presence of penicillinase is up to 350 times higher compared with the free antibiotics. Conjugates with a second antimicrobial function, a dodecyltrimethylammonium group (DDA-X), at the starting end of the PenG and PenV POx conjugates are more antimicrobially active than the conjugates without DDA-X and show high activity in the presence of penicillinase. For example, the conjugates DDA-X-PEtOx-PenG and DDA-X-PEtOx-PenV are 200 to 350 times more active against S. aureus in the presence of penicillinase and almost as effective as the penicillinase stable cloxacollin (Clox) under these conditions. These conjugates show even greater activity compared to cloxacollin without this enzyme present. Further, both conjugates kill Escherichia coli more effectively than PenG and Clox.

  14. 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.

  15. Fluorescence blinking in MEH-PPV single molecules at low temperature

    International Nuclear Information System (INIS)

    Mirzov, O.; Cichos, F.; Borczyskowski, C. von; Scheblykin, I.

    2005-01-01

    Fluorescence intensity transients of single molecules of the conjugated polymer poly[2-methoxy,5-(2'-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) were studied at 15 K. Fluorescence blinking behavior was observed despite the expected low-temperature suppression of energy migration in such disordered molecular systems. Presence of the fluorescence blinking effect at 15 K indicates that the single molecules possess a collapsed conformation with characteristic size of not more than several nanometers, which corresponds to only a few exciton hops over a polymer chain

  16. X-ray diffraction studies of the structure and orientations of thiophene and fluorenone based molecule

    International Nuclear Information System (INIS)

    Porzio, William; Pasini, Mariacecilia; Destri, Silvia; Giovanella, Umberto; Fontaine, Philippe

    2006-01-01

    The crystal structure of a conjugated molecule containing thiophene and fluorenone residues has been determined from powder X-ray diffraction (XRD). Thin films ( -5 Pa) onto oxidized silicon substrates, are oriented along with different crystallographic directions. A comparison of XRD in both Grazing Incidence and Bragg-Brentano geometries allowed to perform a quantitative analysis of the various orientations. This approach is generally applicable in the case of multi-oriented films. The results fully account for the poor performance of this molecule in p-type field effect transistor devices

  17. Organic Molecules in Meteorites

    Science.gov (United States)

    Martins, Zita

    2015-08-01

    Carbonaceous meteorites are primitive samples from the asteroid belt, containing 3-5wt% organic carbon. The exogenous delivery of organic matter by carbonaceous meteorites may have contributed to the organic inventory of the early Earth. The majority (>70%) of the meteoritic organic material consist of insoluble organic matter (IOM) [1]. The remaining meteoritic organic material (meteorites contain soluble organic molecules with different abundances and distributions, which may reflect the extension of aqueous alteration or thermal metamorphism on the meteorite parent bodies. Extensive aqueous alteration on the meteorite parent body may result on 1) the decomposition of α-amino acids [5, 6]; 2) synthesis of β- and γ-amino acids [2, 6-9]; 3) higher relative abundances of alkylated polycyclic aromatic hydrocarbons (PAHs) [6, 10]; and 4) higher L-enantiomer excess (Lee) value of isovaline [6, 11, 12].The soluble organic content of carbonaceous meteorites may also have a contribution from Fischer-Tropsch/Haber-Bosch type gas-grain reactions after the meteorite parent body cooled to lower temperatures [13, 14].The analysis of the abundances and distribution of the organic molecules present in meteorites helps to determine the physical and chemical conditions of the early solar system, and the prebiotic organic compounds available on the early Earth.[1] Cody and Alexander (2005) GCA 69, 1085. [2] Cronin and Chang (1993) in: The Chemistry of Life’s Origin. pp. 209-258. [3] Martins and Sephton (2009) in: Amino acids, peptides and proteins in organic chemistry. pp. 1-42. [4] Martins (2011) Elements 7, 35. [5] Botta et al. (2007) MAPS 42, 81. [6] Martins et al. (2015) MAPS, in press. [7] Cooper and Cronin (1995) GCA 59, 1003. [8] Glavin et al. (2006) MAPS. 41, 889. [9] Glavin et al. (2011) MAPS 45, 1948. [10] Elsila et al. (2005) GCA 5, 1349. [11] Glavin and Dworkin (2009) PNAS 106, 5487. [12] Pizzarello et al. (2003) GCA 67, 1589. [13] Chan et al. (2012) MAPS. 47, 1502

  18. Analysis of lipid raft molecules in the living brain slices.

    Science.gov (United States)

    Kotani, Norihiro; Nakano, Takanari; Ida, Yui; Ito, Rina; Hashizume, Miki; Yamaguchi, Arisa; Seo, Makoto; Araki, Tomoyuki; Hojo, Yasushi; Honke, Koichi; Murakoshi, Takayuki

    2017-08-24

    Neuronal plasma membrane has been thought to retain a lot of lipid raft components which play important roles in the neural function. Although the biochemical analyses of lipid raft using brain tissues have been extensively carried out in the past 20 years, many of their experimental conditions do not coincide with those of standard neuroscience researches such as neurophysiology and neuropharmacology. Hence, the physiological methods for lipid raft analysis that can be compatible with general neuroscience have been required. Herein, we developed a system to physiologically analyze ganglioside GM1-enriched lipid rafts in brain tissues using the "Enzyme-Mediated Activation of Radical Sources (EMARS)" method that we reported (Kotani N. et al. Proc. Natl. Acad. Sci. U S A 105, 7405-7409 (2008)). The EMARS method was applied to acute brain slices prepared from mouse brains in aCSF solution using the EMARS probe, HRP-conjugated cholera toxin subunit B, which recognizes ganglioside GM1. The membrane molecules present in the GM1-enriched lipid rafts were then labeled with fluorescein under the physiological condition. The fluorescein-tagged lipid raft molecules called "EMARS products" distributed differentially among various parts of the brain. On the other hand, appreciable differences were not detected among segments along the longitudinal axis of the hippocampus. We further developed a device to label the lipid raft molecules in acute hippocampal slices under two different physiological conditions to detect dynamics of the lipid raft molecules during neural excitation. Using this device, several cell membrane molecules including Thy1, known as a lipid raft resident molecule in neurons, were confirmed by the EMARS method in living hippocampal slices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Quantitative clinical uptake measurements using conjugate counting

    International Nuclear Information System (INIS)

    Lathrop, K.A.; Bartlett, R.D.; Chen, C.T.; Chou, J.S.; Faulhaber, P.F.; Harper, P.V.; Stark, V.J.

    1986-01-01

    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

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

    KAUST Repository

    Lima, Igo T.; Risko, Chad; Aziz, Saadullah Gary; Da Silva Filho, Demé trio A Da Silva; Bredas, Jean-Luc

    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.

  1. Single-molecule mechanics of protein-labelled DNA handles

    Directory of Open Access Journals (Sweden)

    Vivek S. Jadhav

    2016-01-01

    Full Text Available DNA handles are often used as spacers and linkers in single-molecule experiments to isolate and tether RNAs, proteins, enzymes and ribozymes, amongst other biomolecules, between surface-modified beads for nanomechanical investigations. Custom DNA handles with varying lengths and chemical end-modifications are readily and reliably synthesized en masse, enabling force spectroscopic measurements with well-defined and long-lasting mechanical characteristics under physiological conditions over a large range of applied forces. Although these chemically tagged DNA handles are widely used, their further individual modification with protein receptors is less common and would allow for additional flexibility in grabbing biomolecules for mechanical measurements. In-depth information on reliable protocols for the synthesis of these DNA–protein hybrids and on their mechanical characteristics under varying physiological conditions are lacking in literature. Here, optical tweezers are used to investigate different protein-labelled DNA handles in a microfluidic environment under different physiological conditions. Digoxigenin (DIG-dsDNA-biotin handles of varying sizes (1000, 3034 and 4056 bp were conjugated with streptavidin or neutravidin proteins. The DIG-modified ends of these hybrids were bound to surface-modified polystyrene (anti-DIG beads. Using different physiological buffers, optical force measurements showed consistent mechanical characteristics with long dissociation times. These protein-modified DNA hybrids were also interconnected in situ with other tethered biotinylated DNA molecules. Electron-multiplying CCD (EMCCD imaging control experiments revealed that quantum dot–streptavidin conjugates at the end of DNA handles remain freely accessible. The experiments presented here demonstrate that handles produced with our protein–DNA labelling procedure are excellent candidates for grasping single molecules exposing tags suitable for molecular

  2. Conjugated polymer photovoltaic devices and materials

    International Nuclear Information System (INIS)

    Mozer, A.J.; Niyazi, Serdar Sariciftci

    2006-01-01

    The science and technology of conjugated polymer-based photovoltaic devices (bulk heterojunction solar cells) is highlighted focusing on three major issues, i.e. (i) nano-morphology optimization, (ii) improving charge carrier mobility, (iii) improving spectral sensitivity. Successful strategies towards improved photovoltaic performance are presented using various novel materials, including double-cable polymers, regioregular polymers and low bandgap polymers. The examples presented herein demonstrate that the bulk heterojunction concept is a viable approach towards developing photovoltaic systems by inexpensive solution-based fabrication technologies. (authors)

  3. Complex conjugate poles and parton distributions

    International Nuclear Information System (INIS)

    Tiburzi, B.C.; Detmold, W.; Miller, G.A.

    2003-01-01

    We calculate parton and generalized parton distributions in Minkowski space using a scalar propagator with a pair of complex conjugate poles. Correct spectral and support properties are obtained only after careful analytic continuation from Euclidean space. Alternately the quark distribution function can be calculated from modified cutting rules, which put the intermediate state on its complex mass shells. Distribution functions agree with those resulting from the model's Euclidean space double distribution which we calculate via nondiagonal matrix elements of twist-two operators. Thus one can use a wide class of analytic parametrizations of the quark propagator to connect Euclidean space Green functions to light-cone dominated amplitudes

  4. PET regularization by envelope guided conjugate gradients

    International Nuclear Information System (INIS)

    Kaufman, L.; Neumaier, A.

    1996-01-01

    The authors propose a new way to iteratively solve large scale ill-posed problems and in particular the image reconstruction problem in positron emission tomography by exploiting the relation between Tikhonov regularization and multiobjective optimization to obtain iteratively approximations to the Tikhonov L-curve and its corner. Monitoring the change of the approximate L-curves allows us to adjust the regularization parameter adaptively during a preconditioned conjugate gradient iteration, so that the desired solution can be reconstructed with a small number of iterations

  5. Rhenium 188 labelling of peptide conjugates

    International Nuclear Information System (INIS)

    Melendez-Alafort, Laura

    2001-01-01

    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 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 99m using different coligands. Then the stability, receptor binding and biodistribution of each complex were assessed. 99m Tc-HYNIC-TOC using EDDA as coligand showed the best characteristics, and was superior for tumour imaging in humans than the commercially available 111 In-DTPA-octreotide. The conditions for labelling the HYNIC-TOC conjugate with 188 Re were then optimised using tricine as a co-ligand. A labelling yield of ∼80% was achieved. After purification however, the stability of the complex was low. The use of other coligand systems which had proved useful for 99m Tc labelling was explored, but yields were very poor. Other chelators such as diethylenetriamine pentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA) and mercaptoacetyltriglycine (MAG 3 ) were studied as potential co-ligand agents to label the HYNIC-TOC conjugate with 188 Re but, again low yields of the labelled peptide complexes were achieved. A novel 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 [ 99m Tc(CO) 3 (H 2 O) 3 ] complex to label the HYNIC-TOC conjugate was investigated

  6. Oriented conjugates of monoclonal and single-domain antibodies with quantum dots for flow cytometry and immunohistochemistry diagnostic applications

    Science.gov (United States)

    Sukhanova, Alyona; Even-Desrumeaux, Klervi; Millot, Jean-Marc; Chames, Patrick; Baty, Daniel; Artemyev, Mikhail; Oleinikov, Vladimir; Cohen, Jacques H. M.; Nabiev, Igor

    2012-03-01

    Ideal diagnostic nanoprobes should not exceed 15 nm in size and should contain high-affinity homogeneously oriented capture molecules on their surface. An advanced procedure for antibody (Ab) reduction was used to cleave each Ab into two functional half-Abs, 75-kDa heavy-light chain fragments, each containing an intact antigen-binding site. Affinity purification of half-Abs followed by their linkage to quantum dots (QDs) yielded oriented QD-Ab conjugates whose functionality was considerably improved compared to those obtained using the standard protocols. Ultrasmall diagnostic nanoprobes were engineered through oriented conjugation of QDs with 13-kDa single-domain Abs (sdAbs) derived from llama IgG. sdAbs were tagged with QDs via an additional cysteine residue specifically integrated into the C-terminal region of sdAb using genetic engineering. This approach made it possible to obtain sdAb-QD nanoprobes <12 nm in diameter comprising four copies of sdAbs linked to the same QD in an oriented manner. sdAb-QD conjugates against carcinoembryonic antigen (CEA) and HER2 exhibited an extremely high specificity in flow cytometry; the quality of immunohistochemical labeling of biopsy samples was found to be superior to that of labeling according to the current "gold standard" protocols of anatomo-pathological practice. The nano-bioengineering approaches developed can be extended to oriented conjugation of Abs and sdAbs with different semiconductor, noble metal, or magnetic nanoparticles.

  7. Size and targeting to PECAM vs ICAM control endothelial delivery, internalization and protective effect of multimolecular SOD conjugates.

    Science.gov (United States)

    Shuvaev, Vladimir V; Muro, Silvia; Arguiri, Evguenia; Khoshnejad, Makan; Tliba, Samira; Christofidou-Solomidou, Melpo; Muzykantov, Vladimir R

    2016-07-28

    Controlled endothelial delivery of SOD may alleviate abnormal local surplus of superoxide involved in ischemia-reperfusion, inflammation and other disease conditions. Targeting SOD to endothelial surface vs. intracellular compartments is desirable to prevent pathological effects of external vs. endogenous superoxide, respectively. Thus, SOD conjugated with antibodies to cell adhesion molecule PECAM (Ab/SOD) inhibits pro-inflammatory signaling mediated by endogenous superoxide produced in the endothelial endosomes in response to cytokines. Here we defined control of surface vs. endosomal delivery and effect of Ab/SOD, focusing on conjugate size and targeting to PECAM vs. ICAM. Ab/SOD enlargement from about 100 to 300nm enhanced amount of cell-bound SOD and protection against extracellular superoxide. In contrast, enlargement inhibited endocytosis of Ab/SOD and diminished mitigation of inflammatory signaling of endothelial superoxide. In addition to size, shape is important: endocytosis of antibody-coated spheres was more effective than that of polymorphous antibody conjugates. Further, targeting to ICAM provides higher endocytic efficacy than targeting to PECAM. ICAM-targeted Ab/SOD more effectively mitigated inflammatory signaling by intracellular superoxide in vitro and in animal models, although total uptake was inferior to that of PECAM-targeted Ab/SOD. Therefore, both geometry and targeting features of Ab/SOD conjugates control delivery to cell surface vs. endosomes for optimal protection against extracellular vs. endosomal oxidative stress, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Photoluminescence properties of a novel conjugate of water-soluble CdTe quantum dots to guanine

    Energy Technology Data Exchange (ETDEWEB)

    Feng Xuejiao [North-East Normal University, Changchun 130024 (China); Shang, Qingkun, E-mail: shangqk995@nenu.edu.c [North-East Normal University, Changchun 130024 (China); Liu Hongjian [Relia Diagnostic Systems, Burlingame, CA 94010 (United States); Wang Wenlan; Wang Zhidan; Liu Junyu [North-East Normal University, Changchun 130024 (China)

    2010-04-15

    A novel conjugate of water-soluble CdTe quantum dots to a small biomolecule guanine has been obtained in aqueous phase. The photoluminescence property and the stability of the conjugate increased comparing to CdTe QDs. The interaction between CdTe QDs and guanine was studied by TEM, fluorescence microscope and photoluminescence (PL), IR, UV-Vis spectra. The effects of reflux time, pH value, ionic strength, and the ratio of CdTe QDs to guanine on the photoluminescence properties of conjugate were investigated in detail. The results show that guanine has a great influence on both the photoluminescence property and stability of thioglycolic acid-stabilized CdTe QDs. The formation of coordination and hydrogen bond between guanine molecules and CdTe including thioglycolic acid on its surface may effectively enhance the PL intensity and stability of CdTe QDs. The maximum PL intensity of the conjugate was obtained on the condition with lower ionic strength, less than 30 min reflux time, neutral pH value and 6/1 as molar ratio of guanine to CdTe.

  9. Tunnelling of a molecule

    International Nuclear Information System (INIS)

    Jarvis, P.D.; Bulte, D.P.

    1998-01-01

    A quantum-mechanical description of tunnelling is presented for a one-dimensional system with internal oscillator degrees of freedom. The 'charged diatomic molecule' is frustrated on encountering a barrier potential by its centre of charge not being coincident with its centre of mass, resulting in transitions amongst internal states. In an adiabatic limit, the tunnelling of semiclassical coherent-like oscillator states is shown to exhibit the Hartman and Bueuttiker-Landauer times t H and t BL , with the time dependence of the coherent state parameter for the tunnelled state given by α(t) = α e -iω(t+Δt) , Δt = t H - it BL . A perturbation formalism is developed, whereby the exact transfer matrix can be expanded to any desired accuracy in a suitable limit. An 'intrinsic' time, based on the oscillator transition rate during tunnelling, transmission or reflection, is introduced. In simple situations the resulting intrinsic tunnelling time is shown to vanish to lowest order. In the general case a particular (nonzero) parametrisation is inferred, and its properties discussed in comparison with the literature on tunnelling times for both wavepackets and internal clocks. Copyright (1998) CSIRO Australia

  10. Single molecule tracking

    Science.gov (United States)

    Shera, E. Brooks

    1988-01-01

    A detection system is provided for identifying individual particles or molecules having characteristic emission in a flow train of the particles in a flow cell. A position sensitive sensor is located adjacent the flow cell in a position effective to detect the emissions from the particles within the flow cell and to assign spatial and temporal coordinates for the detected emissions. A computer is then enabled to predict spatial and temporal coordinates for the particle in the flow train as a function of a first detected emission. Comparison hardware or software then compares subsequent detected spatial and temporal coordinates with the predicted spatial and temporal coordinates to determine whether subsequently detected emissions originate from a particle in the train of particles. In one embodiment, the particles include fluorescent dyes which are excited to fluoresce a spectrum characteristic of the particular particle. Photones are emitted adjacent at least one microchannel plate sensor to enable spatial and temporal coordinates to be assigned. The effect of comparing detected coordinates with predicted coordinates is to define a moving sample volume which effectively precludes the effects of background emissions.

  11. Theoretical Investigations Regarding Single Molecules

    DEFF Research Database (Denmark)

    Pedersen, Kim Georg Lind

    Neoclassical Valence Bond Theory, Quantum Transport, Quantum Interference, Kondo Effect, and Electron Pumping. Trap a single organic molecule between two electrodes and apply a bias voltage across this "molecular junction". When electrons pass through the molecule, the different electron paths can...... interfere destructively or constructively. Destructive interference effects in electron transport could potentially improve thermo-electrics, organic logic circuits and energy harvesting. We have investigated destructive interference in off-resonant transport through organic molecules, and have found a set...

  12. Biofuels: from microbes to molecules

    National Research Council Canada - National Science Library

    Lu, Xuefeng

    2014-01-01

    .... The production of different biofuel molecules including hydrogen, methane, ethanol, butanol, higher chain alcohols, isoprenoids and fatty acid derivatives, from genetically engineered microbes...

  13. Labelled molecules, modern research implements

    International Nuclear Information System (INIS)

    Pichat, L.; Langourieux, Y.

    1974-01-01

    Details of the synthesis of carbon 14- and tritium-labelled molecules are examined. Although the methods used are those of classical organic chemistry the preparation of carbon 14-labelled molecules differs in some respects, most noticeably in the use of 14 CO 2 which requires very special handling techniques. For the tritium labelling of organic molecules the methods are somewhat different, very often involving exchange reactions. The following are described in turn: the so-called Wilzbach exchange method; exchange by catalysis in solution; catalytic hydrogenation with tritium; reductions with borotritides. Some applications of labelled molecules in organic chemistry, biochemistry and pharmacology are listed [fr

  14. Evaluation of the site specific protein glycation and antioxidant capacity of rare sugar-protein/peptide conjugates.

    Science.gov (United States)

    Sun, Yuanxia; Hayakawa, Shigeru; Ogawa, Masahiro; Izumori, Ken

    2005-12-28

    Protein-sugar conjugates generated in nonenzymatic glycation of alpha-lactalbumin (LA) with rare sugars [D-allose (All) and D-psicose (Psi)] and alimentary sugars as controls [D-glucose (Glc) and D-fructose (Fru)] were qualitatively determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Mass spectra revealed that the extent of glycation at lysine residues on LA with D-aldose molecules was very much higher than that of glycation with d-ketose molecules. To identify the specific site of glycation, the peptide mapping was established from protease V8 digestion, using a combination of computational cutting of proteins and MALDI-TOF-MS. As compared to peptide mapping, three and seven glycation sites were located in the primary structure of LA-ketose and LA-aldose conjugates, respectively. On the other hand, the antioxidant activities of protein-sugar conjugates and their peptic hydrolysates were investigated by 1,1-diphenyl-2-picrylhydrazyl radical scavenging method. The antioxidant activities of proteins/peptides glycated with rare sugars were significantly higher than those modified with the control sugars. The results indicated that the glycation degree and position were not markedly different between rare sugar and corresponding control sugar, but the antioxidant properties of protein and its hydrolysate were significantly enhanced by modifying with rare sugar.

  15. Synthesis, in vitro and in silico antimalarial activity of 7-chloroquinoline and 4H-chromene conjugates.

    Science.gov (United States)

    Parthiban, A; Muthukumaran, J; Manhas, Ashan; Srivastava, Kumkum; Krishna, R; Rao, H Surya Prakash

    2015-10-15

    A new series of chloroquinoline-4H-chromene conjugates incorporating piperizine or azipane tethers were synthesized and their anti-malarial activity were evaluated against two Plasmodium falciparum strains namely 3D7 chloroquine sensitive (CQS) and K1 chloroquine resistant (CQR). Chloroquine was used as the standard and also reference for comparison. The conjugates exhibit intense UV absorption with λmax located at 342 nm (log ε=4.0), 254 nm (log ε=4.2), 223 nm (log ε=4.4) which can be used to spectrometrically track the molecules even in trace amounts. Among all the synthetic compounds, two molecules namely 6-nitro and N-piperazine groups incorporated 7d and 6-chloro and N-azapane incorporated 15b chloroquinoline-4H-chromene conjugates showed significant anti-malarial activity against two strains (3D7 and K1) of P. falciparum. These values are lesser than the values of standard antimalarial compound. Molecular docking results suggested that these two compounds showing strong binding affinity with P. falciparum lactate dehydrogenase (PfLDH) and also they occupy the co-factor position which indicated that they could be the potent inhibitors for dreadful disease malaria and specifically attack the glycolytic pathway in parasite for energy production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 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.

  17. The multigrid preconditioned conjugate gradient method

    Science.gov (United States)

    Tatebe, Osamu

    1993-01-01

    A multigrid preconditioned conjugate gradient method (MGCG method), which uses the multigrid method as a preconditioner of the PCG method, is proposed. The multigrid method has inherent high parallelism and improves convergence of long wavelength components, which is important in iterative methods. By using this method as a preconditioner of the PCG method, an efficient method with high parallelism and fast convergence is obtained. First, it is considered a necessary condition of the multigrid preconditioner in order to satisfy requirements of a preconditioner of the PCG method. Next numerical experiments show a behavior of the MGCG method and that the MGCG method is superior to both the ICCG method and the multigrid method in point of fast convergence and high parallelism. This fast convergence is understood in terms of the eigenvalue analysis of the preconditioned matrix. From this observation of the multigrid preconditioner, it is realized that the MGCG method converges in very few iterations and the multigrid preconditioner is a desirable preconditioner of the conjugate gradient method.

  18. Growing interstellar molecules with ion-molecule reactions

    International Nuclear Information System (INIS)

    Bohme, D.K.

    1989-01-01

    Laboratory measurements of gas-phase ion-molecule reactions continue to provide important insights into the chemistry of molecular growth in interstellar environments. It is also true that the measurements are becoming more demanding as larger molecules capture our interest. While some of these measurements are motivated by current developments in chemical models of interstellar environments or by new molecular observations by astronomers, others explore novel chemistry which can lead to predictions of new interstellar molecules. Here the author views the results of some recent measurements, taken in the Ion Chemistry Laboratory at York University with the SIFT technique, which address some of the current needs of modellers and observers and which also provide some new fundamental insight into molecular growth, particularly when it occurs in the presence of large molecules such as PAH molecules which are now thought to have a major influence on the chemistry of interstellar environments in which they are present

  19. Evidence of the Disassembly of α-Cyclodextrin-octylamine Inclusion Compounds Conjugated to Gold Nanoparticles via Thermal and Photothermal Effects

    Directory of Open Access Journals (Sweden)

    Nataly Silva

    2016-10-01

    Full Text Available Cyclodextrin (CD molecules form inclusion compounds (ICs, generating dimers that are capable of encapsulating molecules derived from long-chain hydrocarbons. The aim of this study is to evaluate the structural changes experienced by ICs in solution with increasing temperatures. For this, a nuclear magnetic resonance (1H-NMR titration was performed to determinate the stoichiometric α-cyclodextrin (α-CD:octylamine (OA 2:1 and binding constant (k = 2.16 M−2 of ICs. Solution samples of α-CD-OA ICs conjugated with gold nanoparticles (AuNPs were prepared, and 1H-NMR spectra at different temperatures were recorded. Comparatively, 1H-NMR spectra of the sample irradiated with a laser with tunable wavelengths, with plasmons of conjugated AuNPs, were recorded. In this work, we present evidence of the disassembly of ICs conjugated with AuNPs. Thermal studies demonstrated that, at 114 °C, there are reversible rearrangements of the host and guests in the ICs in a solid state. Migration movements of the guest molecules from the CD cavity were monitored via temperature-dependent 1H-NMR, and were verified comparing the chemical shifts of octylamine dissolved in deuterated dimethylsulfoxide (DMSO-d6 with the OA molecule included in α-CD dissolved in the same solvent. It was observed that, at 117 °C, OA exited the α-CD cavity. CD IC dimer disassembly was also observed when the sample was irradiated with green laser light.

  20. Online size-exclusion high-performance liquid chromatography light scattering and differential refractometry methods to determine degree of polymer conjugation to proteins and protein-protein or protein-ligand association states.

    Science.gov (United States)

    Kendrick, B S; Kerwin, B A; Chang, B S; Philo, J S

    2001-12-15

    Characterizing the solution structure of protein-polymer conjugates and protein-ligand interactions is important in fields such as biotechnology and biochemistry. Size-exclusion high-performance liquid chromatography with online classical light scattering (LS), refractive index (RI), and UV detection offers a powerful tool in such characterization. Novel methods are presented utilizing LS, RI, and UV signals to rapidly determine the degree of conjugation and the molecular mass of the protein conjugate. Baseline resolution of the chromatographic peaks is not required; peaks need only be sufficiently separated to represent relatively pure fractions. An improved technique for determining the polypeptide-only mass of protein conjugates is also described. These techniques are applied to determining the degree of erythropoietin glycosylation, the degree of polyethylene glycol conjugation to RNase A and brain-derived neurotrophic factor, and the solution association states of these molecules. Calibration methods for the RI, UV, and LS detectors will also be addressed, as well as online methods to determine protein extinction coefficients and dn/dc values both unconjugated and conjugated protein molecules. (c)2001 Elsevier Science.

  1. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner...... conjugates and their use in vaccination, production of antibodies, high throughput screening, diagnostic assays and libraries....

  2. 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...

  3. The Synthesis of Substituted Piperazine-cholesterol Conjugates for ...

    African Journals Online (AJOL)

    A small library of cholesterol-piperazine conjugates were synthesized by the reaction of cholesteryl chloroformate with a set of substituted piperazines in dichloromethane at room temperature. The conjugates, all obtained in good to excellent yields, were synthesized to be key components of nucleic acid transfection ...

  4. New preconditioned conjugate gradient algorithms for nonlinear unconstrained optimization problems

    International Nuclear Information System (INIS)

    Al-Bayati, A.; Al-Asadi, N.

    1997-01-01

    This paper presents two new predilection conjugate gradient algorithms for nonlinear unconstrained optimization problems and examines their computational performance. Computational experience shows that the new proposed algorithms generally imp lone the efficiency of Nazareth's [13] preconditioned conjugate gradient algorithm. (authors). 16 refs., 1 tab

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

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Cremers, H.F.M.; 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

  6. Photodynamic inactivation of bacteria using polyethylenimine-chlorin(e6) conjugates: Effect of polymer molecular weight, substitution ratio of chlorin(e6) and pH.

    Science.gov (United States)

    Huang, Liyi; Zhiyentayev, Timur; Xuan, Yi; Azhibek, Dulat; Kharkwal, Gitika B; Hamblin, Michael R

    2011-04-01

    Antimicrobial photodynamic therapy (APDT) is a novel technique to treat local infections. Previously we reported that the attachment of chlorin(e6) to polyethylenimine (PEI) polymers to form PEI-ce6 conjugates is an effective way to improve ce6 PDT activity against bacteria. The aim of this work was to explore how the polymer molecular weight, substitution ratio (SR) of ce6 and pH value affect the PDT efficacy. We have synthesized PEI-ce6(10) (MW = 60,000, SR = 1) and PEI-ce6(11) (MW = 60,000, SR = 5) and compared these with the previous PEI-ce6(9) (MW = 10,000, SR = 1). We tested the PDT efficacy of these three conjugates against Gram-negative E. coli and Gram-positive bacteria (S. aureus and E. fecalis) at three different pH values (5.0, 7.4, 10.0) that may affect the charge on both the bacterial cells and on the conjugate (that has both basic and acidic groups). PEI-ce6(9) and PEI-ce6(10) were the most effective against these tested bacteria. The PDT effect of all three conjugates depended on pH values. The effective order was pH = 10.0 > pH = 7.4 > pH = 5.0 on E. coli. For S. aureus and E. fecalis the order was pH = 5.0 > pH = 10.0 > pH = 7.4. PEI-ce6(11) PDT activity was worse than PEI-ce6(10) activity which is probably connected to the fact that ce6 molecules are self-quenched within the PEI-ce6(11) molecule. Ce6 quenching within the PEI-ce6 molecules was proved by analyzing fluorescence spectra of PEI-ce6 conjugates at different pH values. There were no differences in bacterial uptake between different pH values in three PEI-ce6 conjugates. We assume high pH (rather than low pH as was hypothesized) disaggregates the conjugates, so the higher pH was more effective than the lower pH against E. coli. But for Gram-positive bacteria, low pH was more effective possibly due to more overall positive charge on the conjugate. Copyright © 2011 Wiley-Liss, Inc.

  7. Calculation of average molecular parameters, functional groups, and a surrogate molecule for heavy fuel oils using 1H and 13C NMR spectroscopy

    KAUST Repository

    Abdul Jameel, Abdul Gani

    2016-04-22

    Heavy fuel oil (HFO) is primarily used as fuel in marine engines and in boilers to generate electricity. Nuclear Magnetic Resonance (NMR) is a powerful analytical tool for structure elucidation and in this study, 1H NMR and 13C NMR spectroscopy were used for the structural characterization of 2 HFO samples. The NMR data was combined with elemental analysis and average molecular weight to quantify average molecular parameters (AMPs), such as the number of paraffinic carbons, naphthenic carbons, aromatic hydrogens, olefinic hydrogens, etc. in the HFO samples. Recent formulae published in the literature were used for calculating various derived AMPs like aromaticity factor 〖(f〗_a), C/H ratio, average paraffinic chain length (¯n), naphthenic ring number 〖(R〗_N), aromatic ring number〖 (R〗_A), total ring number〖 (R〗_T), aromatic condensation index (φ) and aromatic condensation degree (Ω). These derived AMPs help in understanding the overall structure of the fuel. A total of 19 functional groups were defined to represent the HFO samples, and their respective concentrations were calculated by formulating balance equations that equate the concentration of the functional groups with the concentration of the AMPs. Heteroatoms like sulfur, nitrogen, and oxygen were also included in the functional groups. Surrogate molecules were finally constructed to represent the average structure of the molecules present in the HFO samples. This surrogate molecule can be used for property estimation of the HFO samples and also serve as a surrogate to represent the molecular structure for use in kinetic studies.

  8. Calculation of average molecular parameters, functional groups, and a surrogate molecule for heavy fuel oils using 1H and 13C NMR spectroscopy

    KAUST Repository

    Abdul Jameel, Abdul Gani; Elbaz, Ayman M.; Emwas, Abdul-Hamid M.; Roberts, William L.; Sarathy, Mani

    2016-01-01

    Heavy fuel oil (HFO) is primarily used as fuel in marine engines and in boilers to generate electricity. Nuclear Magnetic Resonance (NMR) is a powerful analytical tool for structure elucidation and in this study, 1H NMR and 13C NMR spectroscopy were used for the structural characterization of 2 HFO samples. The NMR data was combined with elemental analysis and average molecular weight to quantify average molecular parameters (AMPs), such as the number of paraffinic carbons, naphthenic carbons, aromatic hydrogens, olefinic hydrogens, etc. in the HFO samples. Recent formulae published in the literature were used for calculating various derived AMPs like aromaticity factor 〖(f〗_a), C/H ratio, average paraffinic chain length (¯n), naphthenic ring number 〖(R〗_N), aromatic ring number〖 (R〗_A), total ring number〖 (R〗_T), aromatic condensation index (φ) and aromatic condensation degree (Ω). These derived AMPs help in understanding the overall structure of the fuel. A total of 19 functional groups were defined to represent the HFO samples, and their respective concentrations were calculated by formulating balance equations that equate the concentration of the functional groups with the concentration of the AMPs. Heteroatoms like sulfur, nitrogen, and oxygen were also included in the functional groups. Surrogate molecules were finally constructed to represent the average structure of the molecules present in the HFO samples. This surrogate molecule can be used for property estimation of the HFO samples and also serve as a surrogate to represent the molecular structure for use in kinetic studies.

  9. Enzyme Molecules in Solitary Confinement

    Directory of Open Access Journals (Sweden)

    Raphaela B. Liebherr

    2014-09-01

    Full Text Available Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities.

  10. Organizing and addressing magnetic molecules.

    Science.gov (United States)

    Gatteschi, Dante; Cornia, Andrea; Mannini, Matteo; Sessoli, Roberta

    2009-04-20

    Magnetic molecules ranging from simple organic radicals to single-molecule magnets (SMMs) are intensively investigated for their potential applications in molecule-based information storage and processing. The goal of this Article is to review recent achievements in the organization of magnetic molecules on surfaces and in their individual probing and manipulation. We stress that the inherent fragility and redox sensitivity of most SMM complexes, combined with the noninnocent role played by the substrate, ask for a careful evaluation of the structural and electronic properties of deposited molecules going beyond routine methods for surface analysis. Detailed magnetic information can be directly obtained using X-ray magnetic circular dichroism or newly emerging scanning probe techniques with magnetic detection capabilities.

  11. Ion-Molecule Reaction Dynamics.

    Science.gov (United States)

    Meyer, Jennifer; Wester, Roland

    2017-05-05

    We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

  12. Kekulé-based Valence Bond Model.I. The Ground-state Properties of Conjugated π-Systems

    Institute of Scientific and Technical Information of China (English)

    LI,Shu-Hua(黎书华); MA,Jing(马晶); JIANG,Yuan-Sheng(江元生)

    2002-01-01

    The Kekulé-based valence bond ( VB ) method, in which the VB model is solved using covalent Kekulé structures as basis functions, is justified in the present work. This method is dimonstrated to provide satisfactory descriptions for resoance energies and bond ang lengths of benzenoid hydrocarbons, being in good agreement with SCF-MO and experimental results. In additicn, an alternative way of discyssing characters of localizedsubstructures within a polyclic benzenoid system is suggested based upon such sunokufied VB calculations. Finally,the symmetries of VB ground states for nonalternant conjugated systems are also illustrated to be obtainable through these calculations, presenting very useful information for understanding the chemical behaviors of some nonalternant conjugated molecules.

  13. Multitarget trehalose-carnosine conjugates inhibit Aβ aggregation, tune copper(II) activity and decrease acrolein toxicity.

    Science.gov (United States)

    Grasso, Giuseppa Ida; Bellia, Francesco; Arena, Giuseppe; Satriano, Cristina; Vecchio, Graziella; Rizzarelli, Enrico

    2017-07-28

    Increasing evidence is accumulating, showing that neurodegenerative disorders are somehow associated with the toxicity of amyloid aggregates, metal ion dyshomeostasis as well as with products generated by oxidative stress. Within the biological oxidation products, acrolein does have a prominent role. A promising strategy to deal with the above neurogenerative disorders is to use multi-functions bio-molecules. Herein, we show how a class of bio-conjugates takes advantage of the antiaggregating, antioxidant and antiglycating properties of trehalose and carnosine. Their ability to sequester acrolein and to inhibit both self- and metal-induced aggregation is here reported. The copper(II) coordination properties of a new trehalose-carnosine conjugate and the relative antioxidant effects have also been investigated. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Phase-conjugate resonant holographic interferometry applied to NH concentration measurements in a 2D diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    Tzannis, A P; Beaud, P; Frey, H M; Gerber, T; Mischler, B; Radi, P P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Resonant Holographic Interferometry is a method based on the anomalous dispersion of light having a frequency close to an electronic transition of a molecule. We propose a novel single-laser, two-colour setup for recording resonant holograms and apply it to 2D species concentration measurements. The second colour is generated by optical phase-conjugation from Stimulated Brillouin scattering in a cell. Phase-Conjugate Resonant Holographic Interferometry (PCRHI) is demonstrated in a 2D NH{sub 3}/O{sub 2} flame yielding interferograms that contain information on the NH radical distribution in the flame. Experimental results are quantified by applying a numerical computation of the Voigt profiles. (author) 1 fig., 3 refs.

  15. Enhanced photodynamic efficacy of zinc phthalocyanine by conjugating to heptalysine.

    Science.gov (United States)

    Li, Linsen; Luo, Zhipu; Chen, Zhuo; Chen, Jincan; Zhou, Shanyong; Xu, Peng; Hu, Ping; Wang, Jundong; Chen, Naisheng; Huang, Jinling; Huang, Mingdong

    2012-11-21

    Zinc phthalocyanine (ZnPc) is a promising photosensitizer for photodynamic therapy, but faces some challenges: ZnPc is insoluble in water and thus requires either special formulation of ZnPc by, e.g., liposome or Cremophor EL, or chemical modification of Pc ring to enhance its bioavailability and photodynamic efficacy. Here, we conjugated monosubstituted ZnPc-COOH with a series of oligolysine moieties with different numbers of lysine residues (ZnPc-(Lys)(n) (n = 1, 3, 5, 7, 9) to improve the water solubility of the ZnPc conjugates. We measured the photosensitizing efficacies and the cellular uptakes of this series of conjugates on a normal and a cancerous cell line. In addition, we developed a sensitive in situ method to distinguish the difference in photodynamic efficacy among conjugates. Our results showed that ZnPc-(Lys)(7) has the highest photodynamic efficacy compared to the other conjugates investigated.

  16. Systemic co-delivery of doxorubicin and siRNA using nanoparticles conjugated with EGFR-specific targeting peptide to enhance chemotherapy in ovarian tumor bearing mice

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. W.; Lin, W. J., E-mail: wjlin@ntu.edu.tw [National Taiwan University, Graduate Institute of Pharmaceutical Sciences, School of Pharmacy (China)

    2013-10-15

    This aim of this study was to develop peptide-conjugated nanoparticles (NPs) for systemic co-delivery of siRNA and doxorubicin to enhance chemotherapy in epidermal growth factor receptor (EGFR) high-expressed ovarian tumor bearing mice. The active targeting NPs were prepared using heptapeptide-conjugated poly(d,l-lactic-co-glycolic acid)-poly(ethylene glycol). The particle sizes of peptide-free and peptide-conjugated NPs were 159.3 {+-} 32.5 and 184.0 {+-} 52.9 nm, respectively, with zeta potential -21.3 {+-} 3.8 and -15.3 {+-} 2.8 mV. The peptide-conjugated NPs uptake were more efficient in EGFR high-expressed SKOV3 cells than in EGFR low-expressed HepG2 cells due to heptapeptide specificity. The NPs were used to deliver small molecule anticancer drug (e.g., doxorubicin) and large molecule genetic agent (e.g., siRNA). The IC{sub 50} of doxorubicin-loaded peptide-conjugated NPs (0.09 {+-} 0.06 {mu}M) was significantly lower than peptide-free NPs (5.72 {+-} 2.64 {mu}M). The similar result was observed in siRNA-loaded NPs. The peptide-conjugated NPs not only served as a nanocarrier to efficiently deliver doxorubicin and siRNA to EGFR high-expressed ovarian cancer cells but also increased the intracellular accumulation of the therapeutic agents to induce assured anti-tumor growth effect in vivo.

  17. Quantum dot nanoparticle conjugation, characterization, and applications in neuroscience

    Science.gov (United States)

    Pathak, Smita

    Quantum dot are semiconducting nanoparticles that have been used for decades in a variety of applications such as solar cells, LEDs and medical imaging. Their use in the last area, however, has been extremely limited despite their potential as revolutionary new biological labeling tools. Quantum dots are much brighter and more stable than conventional fluorophores, making them optimal for high resolution imaging and long term studies. Prior work in this area involves synthesizing and chemically conjugating quantum dots to molecules of interest in-house. However this method is both time consuming and prone to human error. Additionally, non-specific binding and nanoparticle aggregation currently prevent researchers from utilizing this system to its fullest capacity. Another critical issue that has not been addressed is determining the number of ligands bound to nanoparticles, which is crucial for proper interpretation of results. In this work, methods to label fixed cells using two types of chemically modified quantum dots are studied. Reproducible non-specific artifact labeling is consistently demonstrated if antibody-quantum dot conditions are less than optimal. In order to explain this, antibodies bound to quantum dots were characterized and quantified. While other groups have qualitatively characterized antibody functionalized quantum dots using TEM, AFM, UV spectroscopy and gel electrophoresis, and in some cases have reported calculated estimates of the putative number of total antibodies bound to quantum dots, no quantitative experimental results had been reported prior to this work. The chemical functionalization and characterization of quantum dot nanocrystals achieved in this work elucidates binding mechanisms of ligands to nanoparticles and allows researchers to not only translate our tools to studies in their own areas of interest but also derive quantitative results from these studies. This research brings ease of use and increased reliability to

  18. Simple test system for single molecule recognition force microscopy

    International Nuclear Information System (INIS)

    Riener, Christian K.; Stroh, Cordula M.; Ebner, Andreas; Klampfl, Christian; Gall, Alex A.; Romanin, Christoph; Lyubchenko, Yuri L.; Hinterdorfer, Peter; Gruber, Hermann J.

    2003-01-01

    We have established an easy-to-use test system for detecting receptor-ligand interactions on the single molecule level using atomic force microscopy (AFM). For this, avidin-biotin, probably the best characterized receptor-ligand pair, was chosen. AFM sensors were prepared containing tethered biotin molecules at sufficiently low surface concentrations appropriate for single molecule studies. A biotin tether, consisting of a 6 nm poly(ethylene glycol) (PEG) chain and a functional succinimide group at the other end, was newly synthesized and covalently coupled to amine-functionalized AFM tips. In particular, PEG 800 diamine was glutarylated, the mono-adduct NH 2 -PEG-COOH was isolated by ion exchange chromatography and reacted with biotin succinimidylester to give biotin-PEG-COOH which was then activated as N-hydroxysuccinimide (NHS) ester to give the biotin-PEG-NHS conjugate which was coupled to the aminofunctionalized AFM tip. The motional freedom provided by PEG allows for free rotation of the biotin molecule on the AFM sensor and for specific binding to avidin which had been adsorbed to mica surfaces via electrostatic interactions. Specific avidin-biotin recognition events were discriminated from nonspecific tip-mica adhesion by their typical unbinding force (∼40 pN at 1.4 nN/s loading rate), unbinding length (<13 nm), the characteristic nonlinear force-distance relation of the PEG linker, and by specific block with excess of free d-biotin. The convenience of the test system allowed to evaluate, and compare, different methods and conditions of tip aminofunctionalization with respect to specific binding and nonspecific adhesion. It is concluded that this system is well suited as calibration or start-up kit for single molecule recognition force microscopy

  19. Glycomics: revealing the dynamic ecology and evolution of sugar molecules.

    Science.gov (United States)

    Springer, Stevan A; Gagneux, Pascal

    2016-03-01

    Sugars are the most functionally and structurally diverse molecules in the biological world. Glycan structures range from tiny single monosaccharide units to giant chains thousands of units long. Some glycans are branched, their monosaccharides linked together in many different combinations and orientations. Some exist as solitary molecules; others are conjugated to proteins and lipids and alter their collective functional properties. In addition to structural and storage roles, glycan molecules participate in and actively regulate physiological and developmental processes. Glycans also mediate cellular interactions within and between individuals. Their roles in ecology and evolution are pivotal, but not well studied because glycan biochemistry requires different methods than standard molecular biology practice. The properties of glycans are in some ways convenient, and in others challenging. Glycans vary on organismal timescales, and in direct response to physiological and ecological conditions. Their mature structures are physical records of both genetic and environmental influences during maturation. We describe the scope of natural glycan variation and discuss how studying glycans will allow researchers to further integrate the fields of ecology and evolution. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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

  1. 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

  2. Conjugate Heat Transfer Study in Hypersonic Flows

    Science.gov (United States)

    Sahoo, Niranjan; Kulkarni, Vinayak; Peetala, Ravi Kumar

    2018-04-01

    Coupled and decoupled conjugate heat transfer (CHT) studies are carried out to imitate experimental studies for heat transfer measurement in hypersonic flow regime. The finite volume based solvers are used for analyzing the heat interaction between fluid and solid domains. Temperature and surface heat flux signals are predicted by both coupled and decoupled CHT analysis techniques for hypersonic Mach numbers. These two methodologies are also used to study the effect of different wall materials on surface parameters. Effectiveness of these CHT solvers has been verified for the inverse problem of wall heat flux recovery using various techniques reported in the literature. Both coupled and decoupled CHT techniques are seen to be equally useful for prediction of local temperature and heat flux signals prior to the experiments in hypersonic flows.

  3. A fast, preconditioned conjugate gradient Toeplitz solver

    Science.gov (United States)

    Pan, Victor; Schrieber, Robert

    1989-01-01

    A simple factorization is given of an arbitrary hermitian, positive definite matrix in which the factors are well-conditioned, hermitian, and positive definite. In fact, given knowledge of the extreme eigenvalues of the original matrix A, an optimal improvement can be achieved, making the condition numbers of each of the two factors equal to the square root of the condition number of A. This technique is to applied to the solution of hermitian, positive definite Toeplitz systems. Large linear systems with hermitian, positive definite Toeplitz matrices arise in some signal processing applications. A stable fast algorithm is given for solving these systems that is based on the preconditioned conjugate gradient method. The algorithm exploits Toeplitz structure to reduce the cost of an iteration to O(n log n) by applying the fast Fourier Transform to compute matrix-vector products. Matrix factorization is used as a preconditioner.

  4. Double diffusive conjugate heat transfer: Part I

    Science.gov (United States)

    Azeem, Soudagar, Manzoor Elahi M.

    2018-05-01

    The present work is undertaken to investigate the effect of solid wall being placed at left of square cavity filled with porous medium. The presence of a solid wall in the porous medium turns the situation into a conjugate heat transfer problem. The boundary conditions are such that the left vertical surface is maintained at highest temperature and concentration whereas right vertical surface at lowest temperature and concentration in the medium. The top and bottom surfaces are adiabatic. The additional conduction equation along with the regular momentum and energy equations of porous medium are solved in an iterative manner with the help of finite element method. It is seen that the heat and mass transfer rate is lesser due to smaller thermal and concentration gradients.

  5. Conjugated Polymers Atypically Prepared in Water

    Science.gov (United States)

    Invernale, Michael A.; Pendergraph, Samuel A.; Yavuz, Mustafa S.; Ombaba, Matthew; Sotzing, Gregory A.

    2010-01-01

    Processability remains a fundamental issue for the implementation of conducting polymer technology. A simple synthetic route towards processable precursors to conducting polymers (main chain and side chain) was developed using commercially available materials. These soluble precursor systems were converted to conjugated polymers electrochemically in aqueous media, offering a cheaper and greener method of processing. Oxidative conversion in aqueous and organic media each produced equivalent electrochromics. The precursor method enhances the yield of the electrochromic polymer obtained over that of electrodeposition, and it relies on a less corruptible electrolyte bath. However, electrochemical conversion of the precursor polymers often relies on organic salts and solvents. The ability to achieve oxidative conversion in brine offers a less costly and a more environmentally friendly processing step. It is also beneficial for biological applications. The electrochromics obtained herein were evaluated for electronic, spectral, and morphological properties. PMID:20959869

  6. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

    Science.gov (United States)

    Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João ARG; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

    2016-01-01

    Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity. PMID:27563243

  7. Synthesis and evaluation of "AZT-HEPT", "AZT-pyridinone", and "ddC-HEPT" conjugates as inhibitors of HIV reverse transcriptase.

    Science.gov (United States)

    Pontikis, R; Dollé, V; Guillaumel, J; Dechaux, E; Note, R; Nguyen, C H; Legraverend, M; Bisagni, E; Aubertin, A M; Grierson, D S; Monneret, C

    2000-05-18

    To test the concept that HIV reverse transcriptase could be effectively inhibited by "mixed site inhibitors", a series of seven conjugates containing both a nucleoside analogue component (AZT 1, ddC 2) and a nonnucleoside type inhibitor (HEPT analogue 12, pyridinone 27) were synthesized and evaluated for their ability to block HIV replication. The (N-3 and C-5)AZT-HEPT conjugates 15, 22, and 23 displayed 2-5 microM anti-HIV activity, but they had no effect on the replication of HIV-2 or the HIV-1 strain with the Y181C mutation. The (C-5)AZT-pyridinone conjugates 34-37 were found to be inactive. In marked contrast, the ddC-HEPT molecule 26 displayed the same potency (EC(50) = 0.45 microM) against HIV-1 (wild type and the Y181C nevirapine-resistant strain) and HIV-2 in cell culture. No synergistic effect was observed for these bis-substrate inhibitors, suggesting that the two individual inhibitor components in these molecules do not bind simultaneously in their respective sites. Interestingly, however, the results indicate that the AZT-HEPT conjugates and the ddC-HEPT derivative 26 inhibit reverse transcriptase (RT) in an opposite manner. One explanation for this difference is that the former compounds interact preferentially with the hydrophobic pocket in RT, whereas 26 (after supposed triphosphorylation) inhibits RT through binding in the catalytic site.

  8. Single Molecule Electronics and Devices

    Science.gov (United States)

    Tsutsui, Makusu; Taniguchi, Masateru

    2012-01-01

    The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. PMID:22969345

  9. Maillard Conjugation of Sodium Alginate to Whey Protein for Enhanced Resistance to Surfactant-Induced Competitive Displacement from Air-Water Interfaces.

    Science.gov (United States)

    Cai, Bingqing; Saito, Anna; Ikeda, Shinya

    2018-01-24

    Whey protein adsorbed to an interface forms a viscoelastic interfacial film but is displaced competitively from the interface by a small-molecule surfactant added afterward. The present study evaluated the impact of the covalent conjugation of high- or low-molecular-weight sodium alginate (HA or LA) to whey protein isolate (WPI) via the Maillard reaction on the ability of whey protein to resist surfactant-induced competitive displacement from the air-water interface. Surfactant added after the pre-adsorption of conjugate to the interface increased surface pressure. At a given surface pressure, the WPI-LA conjugate showed a significantly higher interfacial area coverage and lower interfacial film thickness compared to those of the WPI-HA conjugate or unconjugated WPI. The addition of LA to the aqueous phase had little effect on the interfacial area and thickness of pre-adsorbed WPI. These results suggest the importance of the molecular weight of the polysaccharide moiety in determining interfacial properties of whey protein-alginate conjugates.

  10. A comprehensive study of extended tetrathiafulvalene cruciform molecules for molecular electronics: synthesis and electrical transport measurements.

    Science.gov (United States)

    Parker, Christian R; Leary, Edmund; Frisenda, Riccardo; Wei, Zhongming; Jennum, Karsten S; Glibstrup, Emil; Abrahamsen, Peter Bæch; Santella, Marco; Christensen, Mikkel A; Della Pia, Eduardo Antonio; Li, Tao; Gonzalez, Maria Teresa; Jiang, Xingbin; Morsing, Thorbjørn J; Rubio-Bollinger, Gabino; Laursen, Bo W; Nørgaard, Kasper; van der Zant, Herre; Agrait, Nicolas; Nielsen, Mogens Brøndsted

    2014-11-26

    Cruciform-like molecules with two orthogonally placed π-conjugated systems have in recent years attracted significant interest for their potential use as molecular wires in molecular electronics. Here we present synthetic protocols for a large selection of cruciform molecules based on oligo(phenyleneethynylene) (OPE) and tetrathiafulvalene (TTF) scaffolds, end-capped with acetyl-protected thiolates as electrode anchoring groups. The molecules were subjected to a comprehensive study of their conducting properties as well as their photophysical and electrochemical properties in solution. The complex nature of the molecules and their possible binding in different configurations in junctions called for different techniques of conductance measurements: (1) conducting-probe atomic force microscopy (CP-AFM) measurements on self-assembled monolayers (SAMs), (2) mechanically controlled break-junction (MCBJ) measurements, and (3) scanning tunneling microscopy break-junction (STM-BJ) measurements. The CP-AFM measurements showed structure-property relationships from SAMs of series of OPE3 and OPE5 cruciform molecules; the conductance of the SAM increased with the number of dithiafulvene (DTF) units (0, 1, 2) along the wire, and it increased when substituting two arylethynyl end groups of the OPE3 backbone with two DTF units. The MCBJ and STM-BJ studies on single molecules both showed that DTFs decreased the junction formation probability, but, in contrast, no significant influence on the single-molecule conductance was observed. We suggest that the origins of the difference between SAM and single-molecule measurements lie in the nature of the molecule-electrode interface as well as in effects arising from molecular packing in the SAMs. This comprehensive study shows that for complex molecules care should be taken when directly comparing single-molecule measurements and measurements of SAMs and solid-state devices thereof.

  11. Selective Covalent Conjugation of Phosphorothioate DNA Oligonucleotides with Streptavidin

    Directory of Open Access Journals (Sweden)

    Christof M. Niemeyer

    2011-08-01

    Full Text Available Protein-DNA conjugates have found numerous applications in the field of diagnostics and nanobiotechnology, however, their intrinsic susceptibility to DNA degradation by nucleases represents a major obstacle for many applications. We here report the selective covalent conjugation of the protein streptavidin (STV with phosphorothioate oligonucleotides (psDNA containing a terminal alkylthiolgroup as the chemically addressable linking unit, using a heterobifunctional NHS-/maleimide crosslinker. The psDNA-STV conjugates were synthesized in about 10% isolated yields. We demonstrate that the terminal alkylthiol group selectively reacts with the maleimide while the backbone sulfur atoms are not engaged in chemical conjugation. The novel psDNA-STV conjugates retain their binding capabilities for both biotinylated macromolecules and the complementary nucleic acid. Moreover, the psDNA-STV conjugate retained its binding capacity for complementary oligomers even after a nuclease digestion step, which effectively degrades deoxyribonucleotide oligomers and thus the binding capability of regular DNA-STV conjugates. The psDNA-STV therefore hold particular promise for applications e.g. in proteome research and novel biosensing devices, where interfering endogenous nucleic acids need to be removed from analytes by nuclease digestion.

  12. 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.

  13. 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.

  14. Characterization of self-assembled redox polymer and antibody molecules on thiolated gold electrodes.

    Science.gov (United States)

    Calvo, E J; Danilowicz, C; Lagier, C M; Manrique, J; Otero, M

    2004-05-15

    Multilayer immobilization of antibody and redox polymer molecules on a gold electrode was achieved, as a strategy for the potential development of an amperometric immunosensor. The step-by-step assembly of antibiotin IgG on Os(bpy)(2)ClPyCH(2)NH poly(allylamine) redox polymer (PAH-Os) adsorbed on thiolated gold electrodes was proved by quartz crystal microbalance (QCM) and atomic force microscopy (AFM) experiments, confirming the electrochemical evidence. The increase of redox charge during the layer-by-layer deposition demonstrated that charge propagation within the layers is feasible. The multilayer structure proved to be effective for the molecular recognition of horseradish peroxidase-biotin conjugate (HRP-biotin), as confirmed by the QCM measurements and the electrocatalytic reduction current obtained upon H(2)O(2) addition. The catalytic current resulting from PAH-Os mediation was shown to increase with the number of assembled layers. Furthermore, the inventory of IgG molecules on the supramolecular self-assembled structure and the specific and non-specific binding of HRP-biotin conjugate were confirmed by the QCM transient studies, giving information on the kinetics of IgG deposition and HRP-biotin conjugate binding to the IgG.

  15. Spin tunneling in magnetic molecules

    Science.gov (United States)

    Kececioglu, Ersin

    In this thesis, we will focus on spin tunneling in a family of systems called magnetic molecules such as Fe8 and Mn12. This is comparatively new, in relation to other tunneling problems. Many issues are not completely solved and/or understood yet. The magnetic molecule Fe 8 has been observed to have a rich pattern of degeneracies in its magnetic spectrum. We focus on these degeneracies from several points of view. We start with the simplest anisotropy Hamiltonian to describe the Fe 8 molecule and extend our discussion to include higher order anisotropy terms. We give analytical expressions as much as we can, for the degeneracies in the semi-classical limit in both cases. We reintroduce jump instantons to the instanton formalism. Finally, we discuss the effect of the environment on the molecule. Our results, for all different models and techniques, agree well with both experimental and numerical results.

  16. Experimental decoherence in molecule interferometry

    International Nuclear Information System (INIS)

    Hackermueller, L.; Hornberger, K.; Stibor, A.; Zeilinger, A.; Arndt, M.; Kiesewetter, G.

    2005-01-01

    Full text: We present three mechanisms of decoherence that occur quite naturally in matter wave interferometer with large molecules. One way molecules can lose coherence is through collision with background gas particles. We observe a loss of contrast with increasing background pressure for various types of gases. We can understand this phenomenon quantitatively with a new model for collisional decoherence which corrects older models by a factor of 2 π;. The second experiment studies the thermal emission of photons related to the high internal energy of the interfering molecules. When sufficiently many or sufficiently short photons are emitted inside the interferometer, the fringe contrast is lost. We can continuously vary the temperature of the molecules and compare the loss of contrast with a model based on decoherence theory. Again we find good quantitative agreement. A third mechanism that influences our interference pattern is dephasing due to vibrations of the interference gratings. By adding additional vibrations we study this effect in more detail. (author)

  17. Photoionization of atoms and molecules

    International Nuclear Information System (INIS)

    Samson, J.A.R.

    1976-01-01

    A literature review on the present state of knowledge in photoionization is presented. Various experimental techniques that have been developed to study photoionization, such as fluorescence and photoelectron spectroscopy, mass spectroscopy, are examined. Various atoms and molecules were chosen to illustrate these techniques, specifically helium and xenon atoms and hydrogen molecules. Specialized photoionization such as in positive and negative ions, excited states, and free radicals is also treated. Absorption cross sections and ionization potentials are also discussed

  18. Low pressure tritiation of molecules

    International Nuclear Information System (INIS)

    Moran, T.F.; Powers, J.C.; Lively, M.O.

    1980-01-01

    A method is described of tritiating sensitive biological molecules by depositing molecules of the substance to be tritiated on a supporting substrate in an evacuated vacuum chamber near, but not in the path of, an electron beam which traverses the chamber, admitting tritium gas into the chamber, and subjecting the tritium to the electron beam. Vibrationally excited tritium gas species are generated which collide and react with the substance thus incorporating tritium atoms into the substance. (U.K.)

  19. Multiscale Modeling of Antibody Drug Conjugates: Connecting tissue and cellular distribution to whole animal pharmacokinetics and potential implications for efficacy

    Science.gov (United States)

    Cilliers, Cornelius; Guo, Hans; Liao, Jianshan; Christodolu, Nikolas; Thurber, Greg M.

    2016-01-01

    Antibody drug conjugates exhibit complex pharmacokinetics due to their combination of macromolecular and small molecule properties. These issues range from systemic concerns, such as deconjugation of the small molecule drug during the long antibody circulation time or rapid clearance from non-specific interactions, to local tumor tissue heterogeneity, cell bystander effects, and endosomal escape. Mathematical models can be used to study the impact of these processes on overall distribution in an efficient manner, and several types of models have been used to analyze varying aspects of antibody distribution including physiologically based pharmacokinetic (PBPK) models and tissue-level simulations. However, these processes are quantitative in nature and cannot be handled qualitatively in isolation. For example, free antibody from deconjugation of the small molecule will impact the distribution of conjugated antibodies within the tumor. To incorporate these effects into a unified framework, we have coupled the systemic and organ-level distribution of a PBPK model with the tissue-level detail of a distributed parameter tumor model. We used this mathematical model to analyze new experimental results on the distribution of the clinical antibody drug conjugate Kadcyla in HER2 positive mouse xenografts. This model is able to capture the impact of the drug antibody ratio (DAR) on tumor penetration, the net result of drug deconjugation, and the effect of using unconjugated antibody to drive ADC penetration deeper into the tumor tissue. This modeling approach will provide quantitative and mechanistic support to experimental studies trying to parse the impact of multiple mechanisms of action for these complex drugs. PMID:27287046

  20. Modern methods for the synthesis of peptide-oligonucleotide conjugates

    International Nuclear Information System (INIS)

    Zubin, Evgenii M; Oretskaya, Tat'yana S; Romanova, Elena A

    2002-01-01

    The published data on the methods of chemical solution and solid-phase synthesis of peptide-oligonucleotide conjugates are reviewed. The known methods are systematised and their advantages and disadvantages are considered. The approaches to the solution synthesis of peptide-oligonucleotide conjugates are systematised according to the type of chemical bonds between the fragments, whereas those to the solid-phase synthesis are classified according to the procedure used for the preparation of conjugates, viz., stepwise elongation of oligonucleotide and peptide chains on the same polymeric support or solid-phase condensation of two presynthesised fragments. The bibliography includes 141 references.