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Complexes Results (complex + result)
Selected AbstractsLeaps of faith: Is forgiveness a useful concept?THE INTERNATIONAL JOURNAL OF PSYCHOANALYSIS, Issue 5 2008Henry F. Smith Using detailed clinical vignettes, the author argues that, despite the current idealization of the concept of forgiveness, the term has no place in psychoanalytic work, and there are some hazards to giving it one. Clinically, the concept of forgiveness is seductive, implying that there should be a common outcome to a variety of injuries, stemming from different situations and calling for different solutions. Every instance of what we call forgiveness can be seen to serve a different defensive function. While the conscious experience of what is called forgiveness is sometimes confused with the unconscious process of reparation, the two can only be described at different levels of psychic life. Despite the fact that in ,the unconscious' there is no such thing as forgiveness, the term has an adhesive quality in our thinking that also blunts the analyst''s appreciation of the aggressive components in the work. In a final vignette, the author illustrates an analytic outcome that has the appearance of forgiveness, but is best understood as the complex result of the everyday work of analysis. [source] A PCP-Pincer RuII,Terpyridine Building Block as a Potential "Antenna Unit" for Intramolecular SensitizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007Marcella Gagliardo Abstract The redox- and photoactive mononuclear complex [Ru(PCP)(tpy,DTTANa4)]Cl {PCP = [C6H3(CH2PPh2)2 -2,6],; tpy,DTTA4, = 4,-(2,2,:6,,2,-terpyridine)-diethylenetriamine- N,N,N,,N, -tetraacetate} possesses an externally directed, vacant N3O4 polyaminocarboxylate-type binding site that coordinates to lanthanide(III) ions to give the neutral heterodinuclear RuII,LnIII complexes [Ru(PCP)(tpy,DTTA)Ln(H2O)2] (Ln = Gd3+, Eu3+). The photophysical properties of solutions of the mononuclear complex [Ru(PCP)(tpy,DTTANa4)]Cl were investigated in MeOH/EtOH (1:4) and compared to those of the solutions of heterodinuclear complexes [Ru(PCP)(tpy,DTTA)Ln(H2O)2] (Ln = Gd3+, Eu3+). Rigid matrix excitation at 77 K of the ,,* level of the ruthenium chromophore in the [Ru(PCP)(tpy,DTTA)Eu(H2O)2] complex results in a weak europium(III) emission pointing to a transfer of energy from Ru,Eu as a result of the metal-to-ligand charge-transfer (MLCT) excited state of the ruthenium component to the luminescent lanthanide ion. The excited state lifetime of the europium complex is 0.2 ms in methanol solution. In deuterated solvents, the lifetime increases to 0.4 ms, which indicates that the process is solvent-dependent as a result of the strongly coordinated molecules of water that are responsible for the quenching in nondeuterated solvents.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] When simplicity is not parsimonious: a priori and a posteriori methods in historical biogeographyJOURNAL OF BIOGEOGRAPHY, Issue 1 2001Marco G. P. Van Veller Despite using the same null hypothesis, a priori and a posteriori approaches in historical biogeography differ fundamentally. Methods such as Component Analysis (CA) and Reconciled Tree Analysis (RTA) may eliminate or modify input data in order to maximize fit to the null hypothesis, by invoking assumptions 1 and 2. Methods such as Brooks Parsimony Analysis (BPA) modify the null hypothesis, if necessary, to maintain the integrity of the input data, as required by assumption 0. Two exemplars illustrate critical empirical differences between CA/RTA and BPA: (1) CA rather than BPA may select the incorrect general area cladogram for a set of data (2) BPA, not RTA, provides the most parsimonious interpretation of all available data and (3) secondary BPA, proposed in 1990, applied to data sets for which dispersal producing areas with reticulate histories is most parsimonious, provides biologically realistic interpretations of area cladograms. These observations lead to the conclusion that BPA and CA/RTA are designed to implement different research programmes based on different conceptual frameworks. BPA is designed to assess the biogeographic context of speciation events, whereas CA/RTA are designed to find the best fitting pattern of relationships among areas based on the taxa that inhabit them. Unique distributional elements and reticulate (hybrid) histories of areas are essential for explaining complex histories of speciation. The conceptual framework for BPA, thus, assumes biogeographical complexity, relying on parsimony as an explanatory tool to summarize complex results, whereas CA/RTA assumes biogeographical simplicity, assuming conceptual parsimony a priori. [source] Control of Biocatalytic Transformations by Programmed DNA AssembliesCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2010Ronit Freeman Abstract This study demonstrates the self-assembly of inhibitor/enzyme-tethered nucleic acid fragments or enzyme I-, enzyme II-modified nucleic acids into functional nanostructures that lead to the controlled inhibition of the enzyme or the activation of an enzyme cascade. In one system, the anti-cocaine aptamer subunits are modified with monocarboxy methylene blue (MB+) as the inhibitor and with choline oxidase (ChOx). The cocaine-induced self-assembly of the aptamer subunits complex results in the inhibition of ChOx by MB+. In a further configuration, two nucleic acids of limited complementarity are functionalized at their 3, and 5, ends with glucose oxidase (GOx) and horseradish peroxidase (HRP), respectively, or with MB+ and ChOx. In the presence of a target DNA sequence, synergistic complementary base-pairing occurs, thus leading to stable supramolecular Y-shaped nanostructures of the nucleic acid units. A GOx/HRP bienzyme cascade or the programmed inhibition of ChOx by MB+ is demonstrated in the resulting nucleic acid nanostructures. A quantitative theoretical model that describes the nucleic acid assemblies and that results in the inhibition of ChOx by MB+ or in the activation of the GOx/HRP cascade, respectively, is provided. [source] Tetranuclear Manganese Complexes with [MnII4] and [MnII2MnIII2] Units: Syntheses, Structures, Magnetic Properties, and DFT Study,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 28 2010Lucjan B. Jerzykiewicz Abstract Two tetranuclear manganese compounds, [Mn4(,3,,2 -L)4Br4(LH)4] (1) and [Mn4(,3,,2 -L)2(,,,2 -L)4L2Br2] (2), with cubane and defect dicubane-like cores were synthesized and characterized by single-crystal X-ray diffraction, magnetic measurements, and DFT calculations (LH = 2-methoxyethanol). The magnetic properties of the resulting [Mn4] building blocks are presented and discussed in detail. In particular, in 2 the MnIII,O,MnIII angle 103.12(8)° is the largest observed to date for such a system. The conjunction of antiferromagnetic and ferromagnetic interactions within the tetranuclear mixed-valent MnII2MnIII2 complexes results in an unusual ST = 1 ground state. [source] Gene transfer with modified polyethyleniminesTHE JOURNAL OF GENE MEDICINE, Issue S1 2004Antoine Kichler Abstract Branched and linear polyethylenimines (PEIs) have proven to be efficient and versatile agents for gene delivery in vitro. In addition, systemic administration of positively charged DNA/PEI complexes results in significant reporter gene expression in lungs. However, re-targeting of complexes to organs other than the lung is hampered by non-specific interactions of polyplexes with blood components and non-target cells. Thus, despite considerable transfectional activity, the properties of PEIs need to be further improved. Therefore, various modifications of PEIs have been explored in recent years. For example, to increase the circulation half-life of the DNA complexes, the surface charge of the particles was shielded by grafting hydrophilic polymers such as polyethylene glycols (PEGs) onto their surface. Alternatively, incorporation of certain ligands into the DNA complexes also resulted in charge shielding even without PEGylation. Herein, I review the most recent PEI derivatives, with a special focus on PEGylated and targeted polymers. Copyright © 2004 John Wiley & Sons, Ltd. [source] Fluorescence enhancement of warfarin induced by interaction with ,-cyclodextrinBIOTECHNOLOGY PROGRESS, Issue 4 2009Jacob M. Vasquez Abstract Warfarin is the most common agent used for control and prevention of venous as well as arterial thromboembolism (blood clots). In aqueous media, warfarin forms inclusion complexes with a family of cyclic oligosaccharides, ,, ,, ,-cyclodextrins (CD). The formation of these complexes results in enhancement of the fluorescence of warfarin. Such spectroscopic changes offer a venue for the development of bioanalytical methodologies for warfarin quantification in biological liquids. We characterized the photophysical properties of warfarin in solvents with varying polarity and viscosity. The fluorescence quantum yield of warfarin correlated: (1) strongly with the solvent viscosity (R = 0.979) and (2) weakly with the solvent polarity (R = 0.118). These findings indicate that it is the change of the viscosity, rather than polarity, of the microenvironment that causes the fluorescence enhancement of warfarin upon binding to ,-CD. Utilizing the observed fluorescence enhancement in fluorescence titration measurements, the binding constants of warfarin to ,-CD were obtained (2.6 × 102 M,1,3.7 × 102 M,1). Using multivariable linear analysis, we extracted the stoichiometry of warfarin-,-CD interaction (1:1). © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Metallomacrocycles with a Difference: Macrocyclic Complexes with Exocyclic Ruthenium(II)-Containing DomainsCHEMISTRY - A EUROPEAN JOURNAL, Issue 43 2009Edwin Abstract The templated synthesis of organic macrocycles containing rings of up to 96 atoms and three 2,2,-bipyridine (bpy) units is described. Starting with the bpy-centred ligands 5,5,-bis[3-(1,4-dioxahept-6-enylphenyl)]-2,2,-bipyridine and 5,5,-bis[3-(1,4,7-trioxadec-9-enylphenyl)]-2,2,-bipyridine, we have applied Grubbs' methodology to couple the terminal alkene units of the coordinated ligands in [FeL3]2+ complexes. Hydrogenation and demetallation of the iron(II)-containing macrocyclic complexes results in the isolation of large organic macrocycles. The latter bind {Ru(bpy)2} units to give macrocyclic complexes with exocyclic ruthenium(II)-containing domains. The complex [Ru(bpy)2(L)]2+ (isolated as the hexafluorophosphate salt), in which L=5,5,-bis[3-(1,4,7,10-tetraoxatridec-12-enylphenyl)]-2,2,-bipyridine, undergoes intramolecular ring-closing metathesis to yield a macrocycle which retains the exocyclic {Ru(bpy)2} unit. The poly(ethyleneoxy) domains in the latter macrocycle readily scavenge sodium ions, as proven by single-crystal X-ray diffraction and atomic absorption spectroscopy data for the bulk sample. In addition to the new compounds, a series of model complexes have been fully characterized, and representative single-crystal X-ray structural data are presented for iron(II) and ruthenium(II) acyclic and macrocyclic species. [source] Conductive Nanoscopic Fibrous Assemblies Containing Helical Tetrathiafulvalene StacksCHEMISTRY - AN ASIAN JOURNAL, Issue 9 2009Yoko Tatewaki Dr. Abstract Tetrathiafulvalenes (TTF) S -TTF and R -TTF having four chiral amide end groups self-organize into helical nanofibers in the presence of 2,3,5,6-tetrafluoro-7,7,,8,8,-tetracyano- p -quinodimethane (F4TCNQ). The intermolecular hydrogen bonding among chiral amide end groups and the formation of charge-transfer complexes results in a long one-dimensional supramolecular stacking, and the chirality of the end groups affects the molecular orientation of TTF cores within the stacks. Electronic conductivity of a single helical nanoscopic fiber made of S -TTF and F4TCNQ is determined to be (7.0±3.0)×10,4,S,cm,1 by point-contact current-imaging (PCI) AFM measurement. Nonwoven fabric composed of helical nanofibers shows a semiconducting temperature dependence with an activation energy of 0.18,eV. [source] | |||||||||||||