Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Anchoring

  • membrane anchoring

  • Terms modified by Anchoring

  • anchoring fibril
  • anchoring point
  • anchoring protein

  • Selected Abstracts

    The Effects of Disruption of A Kinase Anchoring Protein,Protein Kinase A Association on Protein Kinase A Signalling in Neuroendocrine Melanotroph Cells of Xenopus laevis

    G. J. H. Corstens
    Abstract The secretory activity of melanotroph cells from Xenopus laevis is regulated by multiple neurotransmitters that act through adenylyl cyclase. Cyclic adenosine monophosphate (cAMP), acting on protein kinase A (PKA), stimulates the frequency of intracellular Ca2+ oscillations and the secretory activity of the melanotroph cell. Anchoring of PKA near target proteins is essential for many PKA-regulated processes, and the family of A kinase anchoring proteins (AKAPs) is involved in the compartmentalisation of PKA type II (PKA II) regulatory subunits. In the present study, we determined to what degree cAMP signalling in Xenopus melanotrophs depends on compartmentalised PKA II. For this purpose, a membrane-permeable stearated form of Ht31 (St-Ht31), which dislodges PKA II from AKAP (thus disrupting PKA II signalling), was used. The effect of St-Ht31 on both secretion of radiolabelled peptides and intracellular Ca2+ signalling by superfused Xenopus melanotrophs was assessed. St-Ht31 stimulated secretion but had no effect on Ca2+ signalling. We conclude Xenopus melanotrophs possess a St-Ht31-sensitive PKA II that is associated with the exocytosis machinery and, furthermore, that Ca2+ signalling is regulated by an AKAP-independent signalling system. Moreover, our results support a recent proposal that AKAP participates in regulating PKA activity independently from cAMP. [source]

    Segregation of the Escherichia coli chromosome terminus

    Yongfang Li
    Summary We studied the segregation of the replication terminus of the Escherichia coli chromosome by time-lapse and still photomicroscopy. The replicated termini lie together at the cell centre. They rapidly segregate away from each other immediately before cell division. At fast growth rate, the copies move progressively and quickly toward the centres of the new-born cells. At slow growth rate, the termini usually remain near the inner cell pole and migrate to the cell centre in the middle of the cell cycle. A terminus domain of about 160kb, roughly centred on the dif recombination site, segregated as a unit at cell division. Sequences outside this domain segregated before division, giving two separate foci in predivision cells. Resolution of chromosome dimers via the terminus dif site requires the XerC recombinase and an activity of the FtsK protein that is thought to align the dif sequences at the cell centre. We found that anchoring of the termini at the cell centre and proper segregation at cell division occurred normally in the absence of recombination via the XerC recombinase. Anchoring and proper segregation were, however, frequently disrupted when the C-terminal domain of FtsK was truncated. [source]

    The brand anchoring effect: A judgment bias resulting from brand awareness and temporary accessibility

    PSYCHOLOGY & MARKETING, Issue 4 2009
    Franz-Rudolf Esch
    Following the Selective Activation, Reconstruction, and Anchoring (SARA) and consumer-based brand equity models, high awareness brands are expected to serve as anchors for forming impressions of co-branded entities. Comparing the brand personality profiles of fictitious brand alliances with high and low awareness brands, the brand anchoring effect is found in Studies 1 and 2. Moreover, Study 3 shows that the effect generalizes to specific brand characteristics and results from making brand-related information more available. Future research on brand awareness and on the brand anchoring effect is discussed. 2009 Wiley Periodicals, Inc. [source]

    Rapid Protein Anchoring into the Membranes of Mammalian Cells Using Oleyl Chain and Poly(ethylene glycol) Derivatives

    Koichi Kato
    The cell membrane is an important interface for communication with extracellular events, and incorporation of bioactive substances, such as antibodies and receptors, into the cell membrane may enhance the potential abilities of cells. Gene manipulation, chemical modification of membrane proteins, and cell surface painting using a GPI anchor have been performed to introduce substances into cell membranes. Furthermore, many lipid anchors have also been used to modify lipid membranes such as liposomes. In this study, we have focused on developing an easy and rapid method for anchoring of substances including macromolecular proteins into the membranes of living mammalian cells. We employed a single oleyl chain derivative coupled with hydrophilic poly(ethylene glycol) (PEG90, the ethyleneoxide (EO) unit is 90) to facilitate solubilization in water. This water-soluble derivative was designated Biocompatible Anchor for Membrane (BAM). Some proteins (streptavidin, EGFP and an antibody) were coupled with BAM90 at the distal terminal of PEG and rapidly (within a few minutes) anchored into the membranes of various cells (NIH3T3, 32D, Ba/F3, hybridoma 9E10). However, the anchored BAM90 disappeared from the cell membranes within 4,5 h in serum-free culture media, and moreover, the retention time of anchoring was shortened (1,2 h) in culture medium containing 10% FBS. We further prepared a dioleylphosphatidylethanolamine (DOPE)-PEG derivative (DOPE-BAM80, the EO unit is 80) as a double oleyl chain derivative for comparison with the single oleyl chain derivative, BAM90. The retention time of anchored DOPE-BAM80 was longer than that of BAM90 and more than 8 h in culture media with and without 10% serum. Furthermore, the treatment time of DOPE-BAM80 for anchoring was nearly as short (within a few minutes) as that of BAM90. In addition, both types of BAMs, BAM90 and DOPE-BAM80, showed no cytotoxicity. Therefore, DOPE-BAM80 is useful for protein anchoring to cells. Although the utilization of BAM90 is considered to be limited, it is expected to useful in restricted environments, for example, in tissues such as the cornea, peritoneum, bladder, and various mucosae, which are less exposed to serum. Thus, we suggest the possibility that both types of BAM can be applied to cell surface engineering. [source]

    A Facile Anchoring of the Bisphosphonate Moiety into Alcohols and Phenols Through Copper Carbenoid Mediated O,H Insertion Reaction.

    CHEMINFORM, Issue 48 2007
    Delphine Lecercle
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    Complex Biohopanoids Synthesis: Efficient Anchoring of Ribosyl Subunits onto a C30,Hopane

    Weidong Pan Dr.
    Abstract Bacteriohopanoids represent a particularly important series of triterpenoids, widely distributed in bacteria. One of the common features of these pentacyclic hopanepolyols is the presence of an extended non-terpenoid and polyhydroxylated side chain attached to the triterpenic moiety through a CC bond. The biological function of biohopanoids also has to be addressed when one considers the broad diversity in both structures and functionalities found in the side chain. Moreover, the stereochemistries of some biohopanoids are still unconfirmed, due to the lack of synthetic methods to prepare them. In this study we describe an efficient methodology for the formation of the CC bond between the C30 -hopane component and C5 -polyhydroxylated carbohydrates through the use of a hopanyllithium intermediate, which has enabled us to synthesize several biohopanoid derivatives. We also report the first synthesis of hopanepentol bearing an additional hydroxy group at position C31. [source]

    Anchoring ,-cyclodextrin to retain fragrances on cotton by means of heterobifunctional reactive dyes

    Wang Chao-Xia
    Cyclodextrins are cyclic oligosaccharides which are able to form complexes with a wide range of organic compounds, including fragrance oils. As a result of the complexation, the vapour pressure of the volatile substance is reduced and its release is better controlled. To achieve this, ,-cyclodextrin can be anchored to cellulose by means of a chemical linkage provided by heterobifunctional reactive dyes. [source]

    The M3/M4 cytoplasmic loop of the ,1 subunit restricts GABAARs lateral mobility: A study using fluorescence recovery after photobleaching,

    CYTOSKELETON, Issue 12 2006
    Macarena Pern
    Abstract A crucial problem in neurobiology is how neurons are able to maintain neurotransmitter receptors at specific membrane domains. The large structural heterogeneity of gamma aminobutyric acid receptors (GABAARs) led to the hypothesis that there could be a link between GABAAR gene diversity and the targeting properties of the receptor complex. Previous studies using Fluorescence Recovery After Photobleaching (FRAP) have shown a restricted mobility in GABAARs containing the ,1 subunit. The M3/M4 cytoplasmic loop is the region of the ,1 subunit with the lowest sequence homology to other subunits. Therefore, we asked whether the M3/M4 loop is involved in cytoskeletal anchoring and GABAAR clustering. A series of ,1 chimeric subunits was constructed: ,1CH (control subunit), ,1CD (Cytoplasmic loop deleted), ,1CD2, and ,1CD3 (,1 with the M3/M4 loop from the ,2 and ,3 subunits, respectively). Our results using FRAP indicate an involvement of the M3/M4 cytoplasmic loop of the ,1 subunit in controlling receptor lateral mobility. On the other hand, inmunocytochemical approaches showed that this domain is not involved in subunit targeting to the cell surface, subunit-subunit assembly, or receptor aggregation. Cell Motil. Cytoskeleton 2006. 2006 Wiley-Liss, Inc. [source]

    A critical step for postsynaptic F-actin organization: Regulation of Baz/Par-3 localization by aPKC and PTEN

    Preethi Ramachandran
    Abstract Actin remodeling has emerged as a critical process during synapse development and plasticity. Thus, understanding the regulatory mechanisms controlling actin organization at synapses is exceedingly important. Here, we used the highly plastic Drosophila neuromuscular junction (NMJ) to understand mechanisms of actin remodeling at postsynaptic sites. Previous studies have suggested that the actin-binding proteins Spectrin and Coracle play a critical role in NMJ development and the anchoring of glutamate receptors most likely through actin regulation. Here, we show that an additional determinant of actin organization at the postsynaptic region is the PDZ protein Baz/Par-3. Decreasing Baz levels in postsynaptic muscles has dramatic consequences for the size of F-actin and spectrin domains at the postsynaptic region. In turn, proper localization of Baz at this site depends on both phosphorylation and dephosphorylation events. Baz phosphorylation by its binding partner, atypical protein kinase C (aPKC), is required for normal Baz targeting to the postsynaptic region. However, the retention of Baz at this site depends on its dephosphorylation mediated by the lipid and protein phosphatase PTEN. Misregulation of the phosphorylation state of Baz by genetic alterations in PTEN or aPKC activity has detrimental consequences for postsynaptic F-actin and spectrin localization, synaptic growth, and receptor localization. Our results provide a novel mechanism of postsynaptic actin regulation through Baz, governed by the antagonistic actions of aPKC and PTEN. Given the conservation of these proteins from worms to mammals, these results are likely to provide new insight into actin organization pathways. 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009 [source]

    Multistep Anchoring Route of Luminescent (5-Amino-1,10-phenanthroline)tris(dibenzoylmethane)europium(III) on Si(100)

    Guglielmo G. Condorelli
    Abstract A multistep route for the covalent anchoring of (5-amino-1,10-phenanthroline)tris(dibenzoylmethane)europium(III)molecules on silicon (100) has been developed. The anchoring route consists of Si functionalization with N -hydroxysuccinimide (NHS) activated carboxylic acid, followed by nucleophilic substitution at the carboxylic acid sites. Characterization of the resulting Si based hybrid materials was achieved by using several complementary techniques: X-ray photoelectron spectroscopy (XPS), attenuated total reflection FTIR spectroscopy (ATR-FTIR), AFM and fluorescence spectroscopy. Comparison of results obtained for NHS activated Si surfaces with those of inert alkyl functionalized Si surfaces proved the covalent anchoring of the Eu complex and ruled out the presence of physisorbed Eu species. The 1.8 nm thickness of the grafted layer, estimated by atomic-force lithography, is compatible with the presence of the anchored complex on the surface. Fluorescence measurements proved that luminescence properties are retained in the grafted complex. [source]

    Expression of zonula occludens-1 (ZO-1) and the transcription factor ZO-1-associated nucleic acid-binding protein (ZONAB),MsY3 in glial cells and colocalization at oligodendrocyte and astrocyte gap junctions in mouse brain

    Mihai C. Penes
    Abstract The PDZ domain-containing protein zonula occludens-1 (ZO-1) interacts with several members of the connexin (Cx) family of gap junction-forming proteins and has been localized to gap junctions, including those containing Cx47 in oligodendrocytes. We now provide evidence for ZO-1 expression in astrocytes in vivo and association with astrocytic connexins by confocal immunofluorescence demonstration of ZO-1 colocalization with astrocytic Cx30 and Cx43, and by ZO-1 coimmunoprecipitation with Cx30 and Cx43. Evidence for direct interaction of Cx30 with ZO-1 was obtained by pull-down assays that indicated binding of Cx30 to the second of the three PDZ domains in ZO-1. Further, we investigated mouse Y-box transcription factor MsY3, the canine ortholog of which has been termed ZO-1-associated nucleic acid-binding protein (ZONAB) and previously reported to interact with ZO-1. By immunofluorescence using specific antimouse ZONAB antibody, ZONAB was found to be associated with oligodendrocytes throughout mouse brain and spinal cord, and to be colocalized with oligodendrocytic Cx47 and Cx32 as well as with astrocytic Cx43. Our results extend the CNS cell types that express the multifunctional protein ZO-1, demonstrate an additional connexin (Cx30) that directly interacts with ZO-1, and show for the first time the association of a transcription factor (ZONAB) with ZO-1 localized to oligodendrocyte and astrocyte gap junctions. Given previous observations that ZONAB and ZO-1 in combination regulate gene expression, our results suggest roles of glial gap junction-mediated anchoring of signalling molecules in a wide variety of glial homeostatic processes. [source]

    Expression of PRiMA in the mouse brain: membrane anchoring and accumulation of ,tailed' acetylcholinesterase

    Nol A. Perrier
    Abstract We analysed the expression of PRiMA (proline-rich membrane anchor), the membrane anchor of acetylcholinesterase (AChE), by in situ hybridization in the mouse brain. We compared the pattern of PRiMA transcripts with that of AChE transcripts, as well as those of choline acetyltransferase and M1 muscarinic receptors which are considered pre- and postsynaptic cholinergic markers. We also analysed cholinesterase activity and its molecular forms in several brain structures. The results suggest that PRiMA expression is predominantly or exclusively related to the cholinergic system and that anchoring of cholinesterases to cell membranes by PRiMA represents a limiting factor for production of the AChE tailed splice variant (AChET),PRiMA complex, which represents the major AChE component in the brain. This enzyme species is mostly associated with cholinergic neurons because the pattern of PRiMA mRNA expression largely coincides with that of ChAT. We also show that, in both mouse and human, PRiMA proteins exist as two alternative splice variants which differ in their cytoplasmic regions. [source]

    How malleable is comparative self-positivity?

    The effects of manipulating judgemental focus, accessibility
    The present research investigated accessibility effects on comparative self-positivity in the environmental domain. In a pretest we established comparative self-positivity and a focus effect for environmental awareness. In the main study we aimed at shifting these effects by manipulating the accessibility of harmful behaviours of either the self or the typical student before obtaining comparative judgements. Specifically, we used two types of accessibility manipulations: anchoring and ease of retrieval. We predicted that judgements would be affected by content in the anchoring paradigm but by subjective ease in the ease of retrieval paradigm. We found the predicted pattern of effects, but it was strongest when participants focused on the typical student. The findings contribute to our understanding of the mechanisms underlying comparative biases and may have applied implications. Copyright 2006 John Wiley & Sons, Ltd. [source]

    Roles of adenine anchoring and ion pairing at the coenzyme B12 -binding site in diol dehydratase catalysis

    FEBS JOURNAL, Issue 24 2008
    Ken-ichi Ogura
    The X-ray structure of the diol dehydratase,adeninylpentylcobalamin complex revealed that the adenine moiety of adenosylcobalamin is anchored in the adenine-binding pocket of the enzyme by hydrogen bonding of N3 with the side chain OH group of Ser,224, and of 6-NH2, N1 and N7 with main chain amide groups of other residues. A salt bridge is formed between the ,-NH2 group of Lys,135 and the phosphate group of cobalamin. To assess the importance of adenine anchoring and ion pairing, Ser,224 and Lys,135 mutants of diol dehydratase were prepared, and their catalytic properties investigated. The S,224A, S,224N and K,135E mutants were 19,2% as active as the wild-type enzyme, whereas the K,135A, K,135Q and K,135R mutants retained 58,76% of the wild-type activity. The presence of a positive charge at the ,135 residue increased the affinity for cobalamins but was not essential for catalysis, and the introduction of a negative charge there prevented the enzyme,cobalamin interaction. The S,224A and S,224N mutants showed a kcat/kinact value that was less than 2% that of the wild-type, whereas for Lys,135 mutants this value was in the range 25,75%, except for the K,135E mutant (7%). Unlike the wild-type holoenzyme, the S,224N and S,224A holoenzymes showed very low susceptibility to oxygen in the absence of substrate. These findings suggest that Ser,224 is important for cobalt,carbon bond activation and for preventing the enzyme from being inactivated. Upon inactivation of the S,224A holoenzyme during catalysis, cob(II)alamin accumulated, and a trace of doublet signal due to an organic radical disappeared in EPR. 5,-Deoxyadenosine was formed from the adenosyl group, and the apoenzyme itself was not damaged. This inactivation was thus considered to be a mechanism-based one. [source]

    Transcription of individual tRNAGly1 genes from within a multigene family is regulated by transcription factor TFIIIB

    FEBS JOURNAL, Issue 20 2005
    Akhila Parthasarthy
    Members of a multigene family from the silkworm Bombyx mori have been classified based on their transcriptions in homologous nuclear extracts, into three groups of highly, moderately and poorly transcribed genes. Because all these gene copies have identical coding sequences and consequently identical promoter elements (the A and B boxes), the flanking sequences modulate their expression levels. Here we demonstrate the interaction of transcription factor TFIIIB with these genes and its role in regulating differential transcriptions. The binding of TFIIIB to the poorly transcribed gene -6,7 was less stable compared with binding of TFIIIB to the highly expressed copy, -1. The presence of a 5, upstream TATA sequence closer to the coding region in -6,7 suggested that the initial binding of TFIIIC to the A and B boxes sterically hindered anchoring of TFIIIB via direct interactions, leading to lower stability of TFIIIC,B-DNA complexes. Also, the multiple TATATAA sequences present in the flanking regions of this poorly transcribed gene successfully competed for TFIIIB reducing transcription. The transcription level could be enhanced to some extent by supplementation of TFIIIB but not by TATA box binding protein. The poor transcription of -6,7 was thus attributed both to the formation of a less stable transcription complex and the sequestration of TFIIIB. Availability of the transcription factor TFIIIB in excess could serve as a general mechanism to initiate transcription from all the individual members of the gene family as per the developmental needs within the tissue. [source]

    The localization change of Ybr078w/Ecm33, a yeast GPI-associated protein, from the plasma membrane to the cell wall, affecting the cellular function

    Hiromichi Terashima
    Abstract The YBR078W/ECM33 gene of Saccharomyces cerevisiae encodes a glycosylphosphatidylinositol (GPI)-attached protein and its disruptant strain exhibited a temperature-sensitive (ts) growth defect. A HA-tagged Ybr078w protein, which complemented the ts growth phenotype of the ybr078w, strain, was predominantly located on the plasma membrane by GPI anchoring. To examine the requirement of the GPI anchoring on the plasma membrane for the function, the ,-minus region of Ybr078w was replaced with those of Ydr534c/Fit1 and Ynl327w/Egt2, which are known as GPI-dependent cell wall proteins. The replacement induced the change in localization of the mutant proteins from the plasma membrane to the cell wall and the mutant proteins lost the function to complement the ts cell growth defect of the ybr078w, strain. In addition, a similar result was obtained in a mutant protein, where the authentic SKKSK sequence at the ,-5 to ,-1 site of Ybr078w was replaced with a synthetic ISSYS sequence. It is concluded that the GPI anchoring on the plasma membrane is required for the Ybr078w function. [source]

    Chemical Bonding Assembly of Multifunctional Oxide Nanocomposites

    Gary Evans
    Abstract The synthesis, functionalization and assembly of metal oxide nanoparticles BaTiO3 and CoFe2O4 is presented. The ferroelectric (BaTiO3) and ferromagnetic (CoFe2O4) oxide nanoparticle surfaces are directly functionalized via the anchoring of phosphonic acid and aminosilane molecules that engender the nanoparticles with terminal carboxylic acid and amine functional groups, respectively. These promote the electrostatic self-assembly of the particles in non-polar solvents and permit the synthesis of more chemically robust assemblies linked by the covalent amide bond via the addition of the chemical coupling agent N - N, -dicyclohexylcarbodiimide. This functionalization and assembly procedure is applied to two systems: the first comprised of 50,nm BaTiO3 and 10,nm CoFe2O4 particles and the second of 200,nm BaTiO3 and 12.5,nm CoFe2O4 particles. The latter composites possess magnetoelectric properties when processed into dense ceramics and, as a direct result of the assembly performed in solution, have a high degree of homogeneity between the ferroelectric and ferromagnetic phases. The developed functionalization and assembly procedure is considered to be adaptable to the preparation of other hybrid oxide nanomaterials with different property combinations. [source]

    Copolymer Film Alignment: Spontaneous Lamellar Alignment in Thickness-Modulated Block Copolymer Films (Adv. Funct.

    Self-alignment of lamellar nanodomains is accomplished by imposing thickness modulation to a block copolymer thin film. Real-time atomic-force microscopy imaging reveals that the self-alignment occurs through the directional growth of well-aligned domains along thickness gradients. This novel self-aligning principle, based on a "geometric anchoring" phenomenon, is reported by S. O. Kim, O. D. Lavrentovich and co-workers on page 2584. [source]

    Novel Brush Polymers with Phosphorylcholine Bristle Ends: Synthesis, Structure, Properties, and Biocompatibility

    Gahee Kim
    Abstract New brush polymers with various numbers of bristle ends incorporating phosphorylcholine (PC) moieties are synthesized. The polymers are thermally stable up to 175,C and form good-quality films with conventional spin-, roll-, and dip-coating, and subsequent drying processes. Interestingly, all these brush polymers, as a PC-containing polymer, demonstrate a stable molecular multi-bilayer structure in thin films that arise due to the efficient self-assembly of the bristles for temperatures <55,C and PC-rich surfaces, and therefore successfully mimic natural cell-membrane surfaces. These brush-polymer films exhibit excellent water wettability and water sorption whilst retaining the remarkable molecular multi-bilayer structure, and thus have hydrophilic surfaces. These novel multi-bilayer structured films repel fibrinogen molecules and platelets from their surfaces but also have bactericidal effects on bacteria. Moreover, the brush-polymer films are found to provide comfortable surface environments for the successful anchoring and growth of HEp-2 cells, and to exhibit excellent biocompatibility in mice. These newly developed brush polymers are suitable for use in biomedical applications including medical devices and biosensors that require biocompatibility and the reduced possibility of post-operative infection. [source]

    Ireland's Foreign-Owned Technology Sector: Evolving Towards Sustainability?

    GROWTH AND CHANGE, Issue 3 2008
    ABSTRACT For some, Ireland's pursuit of an exogenous-led development model has proved to be the cornerstone of recent economic success. Others point to recent high-profile closures and argue that foreign-owned operations are attracted to Ireland solely because of the advantageous tax breaks and lucrative grants scheme offered by the Irish government. We pay tribute to both arguments by pushing the level of enquiry beyond that of supply and backward linkages to try and gauge the actual performance of affiliates themselves. This brings some interesting facets of the Irish foreign direct investment scene to light. We highlight complexity of process, attainment of broader investment remits, and the emergence of a managerial class as integral to the ability of affiliates to adapt to and exploit organisational change. By examining 10 case studies and making use of media searches and company interviews, we highlight evidence of Ireland's largest technology transnational corporation affiliates showing positive performance advances. With these movements come, what we term, increased nodal significance of Irish operations within the global production network of their corporations. We argue against policy and theories that see these movements as linear and provide evidence of how some Irish operations have leveraged control and gained significant regional and global remits that have resulted in their growing significance, both in the corporation and in the country in which they are based. In the same line we argue that embeddedness in terms of supply linkages does not fit the Irish case and instead employ the term "network anchoring" of affiliates as they increase their nodal weighting through increased mandates. [source]

    Dendrimer Precursors for Nanomolar and Picomolar Real-Time Surface Plasmon Resonance/Potentiometric Chemical Nerve Agent Sensing Using Electrochemically Crosslinked Ultrathin Films,

    P. Taranekar
    Abstract Nanomolar detection and specific recognition of pinacolyl methylphosphonate (PMP), a hydrolysis product and an analog of a relatively persistent class of toxic nerve agents, has been achieved. In addition, picomolar sensitivity is observed with methylphosphonic acid (MPA), an end-hydrolysis product for all organophosphate-based nerve agents. This is achieved using a combined surface plasmon resonance (SPR) and potentiometry setup. A modified polyamidoamine (PAMAM) carbazole/Cu2+ dendrimer, which is electrochemically crosslinked on a self-assembled monolayer (SAM) modified Au,substrate, is used as an active sensing element for trapping the nerve-agent analogs. The ultrathin films have been used to study the anchoring of nerve agents via non-covalent interactions. The carbazole to amine ratio is optimized to ensure free primary amines are available to interact with the analyte and the Cu2+ ions present in the system, which further enhances the selectivity. The carbazole group on the periphery serves a dual purpose: crosslinking the dendrimers to form a conjugated network film, and generating the potentiometric response. The adsorption kinetics are monitored by using an in,situ SPR/potentiometric setup. This technique not only offers a real-time dual detection of highly toxic nerve-agent analogs, but also shows viability for future sensor-device applications. [source]

    Alterations of postsynaptic density proteins in the hippocampus of rat offspring from the morphine-addicted mother: Beneficial effect of dextromethorphan

    HIPPOCAMPUS, Issue 6 2006
    San Nan Yang
    Abstract Infants passively exposed to morphine or heroin through their addicted mothers usually develop characteristic withdrawal syndrome of morphine after birth. In such early life, the central nervous system exhibits significant plasticity and can be altered by various prenatal influences, including prenatal morphine exposure. Here we studied the effects of prenatal morphine exposure on postsynaptic density protein 95 (PSD-95), an important cytoskeletal specialization involved in the anchoring of the NMDAR and neuronal nitric oxide synthase (nNOS), of the hippocampal CA1 subregion from young offspring at postnatal day 14 (P14). We also evaluated the therapeutic efficacy of dextromethorphan, a widely used antitussive drug with noncompetitive antagonistic effects on NMDARs, for such offspring. The results revealed that prenatal morphine exposure caused a maximal decrease in PSD-95 expression at P14 followed by an age-dependent improvement. In addition, prenatal morphine exposure reduced not only the expression of nNOS and the phosphorylation of cAMP responsive element-binding protein at serine 133 (CREBSerine-133), but also the magnitude of long-term depression (LTD) at P14. Subsequently, the morphine-treated offspring exhibited impaired performance in long-term learning and memory at later ages (P28,29). Prenatal coadministration of dextromethorphan with morphine during pregnancy and throughout lactation could significantly attenuate the adverse effects as described above. Collectively, the study demonstrates that maternal exposure to morphine decreases the magnitude of PSD-95, nNOS, the phosphorylation of CREBSerine-133, and LTD expression in hippocampal CA1 subregion of young offspring (e.g., P14). Such alterations within the developing brain may play a role for subsequent neurological impairments (e.g., impaired performance of long-term learning and memory). The results raise a possibility that postsynaptic density proteins could serve an important role, at least in part, for the neurobiological pathogenesis in offspring from the morphine-addicted mother and provide tentative therapeutic strategy. 2006 Wiley-Liss, Inc. [source]

    Nanoparticle Supported, Magnetically Recoverable Oxodiperoxo Molybdenum Complexes: Efficient Catalysts for Selective Epoxidation Reactions

    Sankaranarayanapillai Shylesh
    Abstract Organic-inorganic hybrid heterogeneous nanocatalyst systems were synthesized by covalent anchoring of oxodiperoxomolybdenum complexes [(LL)MoO(O2)2] on silica coated magnetic nanoparticles as an active, magnetically separable epoxidation catalyst. [source]

    To what extent do investors in a financial market anchor their judgments excessively?

    Evidence from the Hong Kong horserace betting market
    A naturalistic study was employed to explore a new form of "basic anchoring." In particular, we examined the degree to which decision makers in a financial market, the horserace betting market, anchored their probability judgments excessively on a factor present in the environment at the time the judgments were made and which was relevant and informative to the judgment: the advantage afforded by a horse's barrier-position (BP). The results demonstrated that under certain conditions bettors anchored excessively on BP information revealed at previous race meetings, but not on the most recent race outcomes. In fact, bettors appeared to use the most recent race outcomes appropriately when forming probability estimates; but only when the results were in line with, what were likely to be, their expectations of BP advantage. Bettors with varying levels of expertise were shown to be subject to excessive anchoring, although greater expertise was generally associated with less excessive anchoring. The paper concludes that the manner and degree of basic anchoring in real-world environments is complex. Copyright 2009 John Wiley & Sons, Ltd. [source]

    When effortful thinking influences judgmental anchoring: differential effects of forewarning and incentives on self-generated and externally provided anchors

    Nicholas Epley
    Abstract Two experiments examined the impact of financial incentives and forewarnings on judgmental anchoring effects, or the tendency for judgments of uncertain qualities to be biased in the direction of salient anchor values. Previous research has found no effect of either manipulation on the magnitude of anchoring effects. We argue, however, that anchoring effects are produced by multiple mechanisms,one involving an effortful process of adjustment from "self-generated" anchors, and another involving the biased recruitment of anchor-consistent information from "externally provided" anchors,and that only the former should be influenced by incentives and forewarning. Two studies confirmed these predictions, showing that responses to "self-generated" anchors are influenced by both incentives and forewarnings whereas responses to "externally provided" anchors are not. Discussion focuses on the implications of these effects for debiasing efforts. Copyright 2005 John Wiley & Sons, Ltd. [source]

    The fragile basic anchoring effect

    Noel T. Brewer
    Abstract The anchoring bias, the effect of uninformative anchor numbers on judgments, is a robust finding. In experiments yielding the anchoring bias, typically participants are explicitly asked to compare the anchor and target. A logical question is whether any manner of considering a number will bias peoples' judgment. Wilson et al. (1996) showed that merely presenting a number to people will bias their judgments, a result they termed basic anchoring. The absence of any published studies that followed up on Wilson et al.'s work prompted us to examine the basic anchoring effect in three experiments. The three experiments (N,=,881, 205, and 117) suggest that basic anchoring is a weak effect limited to the precise manipulations used by Wilson et al. Trivial changes such as altering the order of a series of anchor numbers, or using different anchor numbers, eliminated the bias. Our findings suggest that basic anchoring has a much narrower scope of impact than traditional anchoring effects. Copyright 2002 John Wiley & Sons, Ltd. [source]

    Transition metal complexes of a cyclic pseudo hexapeptide: synthesis, complex formation and catalytic activities,,

    Huong Ngyen
    Abstract To contribute to a better understanding of metalloenzymes, we studied ion selectivity, complex formation tendencies and catalytic activities of linear and cyclic pseudopeptides. In this contribution, a linear and cyclic pseudo hexapeptide is described. The complex with transition metal ions and the sequence were designed using the programme COSMOS. Different routes of solid-phase synthesis were performed and compared using anchoring by C -terminus or a His side chain, using preformed pseudodipeptide building units or formation of N -functionalized peptide bond during stepwise assembly. The different strategies were compared regarding cyclization tendency, yield and purity. Side-chain anchoring to solid support favours the cyclization but leads to the formation of difficult to separate dioxopiperazine. Both routes require preformed building units. Complex-formation tendencies and selectivity for certain bivalent transition metal ions were experimentally estimated and compared to ones predicted theoretically. CD measurements indicate conformational changes by complex formation with different metal ions. Catalytic activities on oxidation of catechol and hydrolysis of bis-phosphate esters by some metal complexes of linear and cyclic peptide show only low catalytic activities compared to other model peptides and related metalloenzymes. The preference of the cyclic peptide for complexation of Ni2+ corresponds well to the predictions of COSMOS-NMR force field calculations. Copyright 2008 European Peptide Society and John Wiley & Sons, Ltd. [source]

    Synthesis and characterization of synthetic polymer colloids colloidally stabilized by cationized starch oligomers

    Marianne Gaborieau
    Abstract A method is developed for anchoring enzymatically degraded cationized starch as electrosteric stabilizers onto synthetic latices, using cerium(IV) to create free-radical grafting sites on the starch. Direct anchoring of debranched starch onto a poly(methyl methacrylate) seed latex yields a latex stabilized by well-defined oligosaccharides. Using ,-amylase to randomly cleave starch to form (1,4)-,-glucans, and a comonomer, N -isopropyl acrylamide (NIPAM), whose corresponding polymer exhibits a lower critical solution temperature (LCST), creates a means to synthesize block (or graft) oligomers of oligosaccharide and synthetic polymer, which are water soluble at room temperature. Above 30 C, they become amphiphilic and form self-emulsifying nanoparticles (sometimes termed "frozen micelles") from which a synthetic latex is grown after addition of methyl methacrylate, the collapsed NIPAM-containing entities functioning as a type of in situ seed. This synthesis of stable synthetic latex particles is shown to have a high grafting efficiency. The starch fragments were characterized by 1H solution-state NMR before grafting, and 13C solid-state cross-polarization magic-angle spinning (CP-MAS) NMR was used to characterize the starch oligomers actually grafted on the final latex. 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1836,1852, 2009 [source]


    DT Crowe
    A technique for placement of a long-term arterial catheter that the author developed was used in 20 canine patients. The catheter was used for pressure monitoring and arterial blood sampling. The technique involved the following steps post-sedation and placement of a local anesthetic: 1Clipping and prepping of the medial aspect of the distal tibia and proximal metatarsal region; 2Incision over the medial tibial malleolus just caudal to the cranial tibial muscle-tendon; 3Blunt dissection of the space just caudal to the cranial tibialis tendon; 4Isolation of the cranial tibial artery and loop placement proximally and distally; 5Placement of a 3 Fr. polyurethane 4,8 cm catheter using a Seldinger wire technique; 6Placement of a suture in the periosteium of the distal tibia and anchoring of the catheter with this suture; 7Closure of the skin incision with sutures or staples; 8Bandage application to hold the catheter in place. The entire surgical procedure was done using sterile technique. The catheter was able to be kept in place and working for up to 9 days (averaged 4 days). This compared favorably retrospectively over dorsalis pedis catheters that lasted only a maximum of 4 days. (average 1.5 days). Because of the size of the catheter (3 Fr.) it provided improved waveforms over that observed with the dorsalis pedis catheter (22 g) and its occlusion rate was very low (2 in 20). The cranial tibial artery catheter was found to be particularly effective because the catheter was able to be inserted several cm up the artery and the catheter was able to be anchored well. No major complications were observed with this technique. Because of its effectiveness it is recommended to be used routinely over femoral artery and dorsal pedis artery catheters. [source]

    AB-polymer Networks with Cooligoester and Poly(n -butyl acrylate) Segments as a Multifunctional Matrix for Controlled Drug Release

    Christian Wischke
    Abstract Semi-crystalline AB-copolymer networks from oligo[(, -caprolactone)- co -glycolide]dimethacrylates and n -butylacrylate have recently been shown to exhibit a shape-memory functionality, which may be used for self-deploying and anchoring of implants. In this study, a family of such materials differing in their molar glycolide contents ,G was investigated to determine structure,property functional relationships of unloaded and drug loaded specimens. Drug loading and release were evaluated, as well as their degradation behavior in vitro and in vivo. Higher ,G resulted in higher loading levels by swelling and a faster release of ethacridine lactate, lower melting temperature of polymer crystallites, and a decrease in shape fixity ratio of the programmed temporary shape. For unloaded networks, the material behavior in vivo was independent of the mechanical load associated with different implantation sites and agreed well with data from in vitro degradation studies. Thus, AB networks could be used as novel matrices for biofunctional implants, e.g., for urogenital applications, which can self-anchor in vivo and provide mechanical support, release drugs, and finally degrade in the body to excretable fragments. [source]