Publications by authors named "Chippindale A"

Article Synopsis
  • This paper discusses the creation and organization of polyurethane elastomers using special bis-aromatic urea hydrogen bonding motifs to enhance self-assembly.
  • It details the use of polytetramethylene ether glycol (PTMG) and other diols to form supramolecular polyurethanes with specific molecular weights and distribution.
  • The resulting materials display adjustable mechanical properties and healing capabilities, making them suitable for practical applications like cable coatings.
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Hepatocellular carcinoma is the most common type of primary liver cancer. However, multidrug resistance (MDR) is a major obstacle to the effective chemotherapy of cancer cells. This report documents the rational design, synthesis, and biological evaluation of a novel series of triazolotriazines substituted with CHNH-linked pyridine for use as dual c-Met/MDR inhibitors.

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We ask if three decades and over 1,500 generations of divergent life-history selection on age at reproduction has resulted in the evolution of reproductive isolation (RI) between laboratory populations of Drosophila melanogaster. We tested for premating, postmating-prezygotic, and postzygotic reproductive isolation between three replicate population pairs. Large, evolved differences in body size between selection treatments suggested the potential for prezygotic barriers driven by sexual selection or physical incompatibilities between the sexes.

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Three novel rhenium -heterocyclic carbene complexes, [Re]-NHC-1-3 ([Re] = -Re(CO)Br), were synthesized and characterized using a range of spectroscopic techniques. Photophysical, electrochemical and spectroelectrochemical studies were carried out to probe the properties of these organometallic compounds. Re-NHC-1 and Re-NHC-2 bear a phenanthrene backbone on an imidazole (NHC) ring, coordinating to Re by both the carbene C and a pyridyl group attached to one of the imidazole nitrogen atoms.

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The new, formally Mo(II) complexes [Mo(η-2-R-allyl)(6,6'-dmbipy)(CO)Cl] (6,6'-dmbipy = 6,6'-dimethyl-2,2'-bipyridine; 2-R-allyl = allyl for R = H, 2-methallyl for R = CH) and [Mo(η-2-methallyl)(pTol-bian)(CO)Cl] (pTol-bian = bis(p-tolylimino)acenaphthene) share, in this rare case, the same structural type. The effect of the anionic π-donor ligand X (Cl vs NCS) and the 2-R-allyl substituents on the cathodic behavior was explored. Both ligands play a significant role at all stages of the reduction path.

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The development of stable, efficient chemoselective self-immolative systems, for use in applications such as sensors, requires the optimization of the reactivity and degradation characteristics of the self-immolative unit. In this paper, we describe the effect that the structure of the reporter group has upon the self-immolative efficacy of a prototype system designed for the disclosure of electrophilic alkylating agents. The amine of the reporter group (a nitroaniline unit) was a constituent part of a carbamate that functioned as the self-immolative unit.

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Hybrid bismuth-containing halides are emerging as alternative candidates to lead-containing perovskites for light-harvesting applications, as Bi is isoelectronic with Pb and the presence of an active lone pair of electrons is expected to result in outstanding charge-carrier transport properties. Here, we report a family of one binary and three ternary iodobismuthates containing 1,4-diazabicyclo[2.2.

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Mixed-metal cyanides (CuAu)CN, (AgAu)CN, and (CuAgAu)CN adopt an AuCN-type structure in which metal-cyanide chains pack on a hexagonal lattice with metal atoms arranged in sheets. The interactions between and within the metal-cyanide chains are investigated using density functional theory (DFT) calculations, C solid-state NMR (SSNMR), and X-ray pair distribution function (PDF) measurements. Long-range metal and cyanide order is found within the chains: (-Cu-NC-Au-CN-), (-Ag-NC-Au-CN-), and (-Cu-NC-Ag-NC-Au-CN-).

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Due to its hemizygous inheritance and role in sex determination, the X-chromosome is expected to play an important role in the evolution of sexual dimorphism and to be enriched for sexually antagonistic genetic variation. By forcing the X-chromosome to only be expressed in males over >40 generations, we changed the selection pressures on the X to become similar to those experienced by the Y. This releases the X from any constraints arising from selection in females and should lead to specialization for male fitness, which could occur either via direct effects of X-linked loci or trans-regulation of autosomal loci by the X.

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Many insects enter coma upon exposure to anoxia, a feature routinely exploited by experimentalists to handle them. But the genetic and physiological bases of anoxic coma induction and recovery are only partially understood, as are the long-term consequences for the animal's performance. We examined three populations of (designated B) that have been inadvertently under selection for rapid recovery from CO exposure for nearly 40 years (around 1000 generations) resulting from routine maintenance practices.

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Mesenchymal-epithelial transition factor (c-Met)/HGF overactivation is involved in diverse human cancers.  Herein, we report the synthesis and biological evaluation of thiomethylpyridine-linked triazolotriazines as c-Met kinase inhibitors. Compounds and were more potent than crizotinib on HepG2 cells with IC values of 0.

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An aromatic peptoid analogue of the diphenylalanine dipeptide self-assembles in aqueous solution and the first crystal structure was obtained for this class of compound. This reveals molecular packing stabilized by networks of hydrogen bonds. Free-floating nanosheet lamellar structures are observed in solution, which form via cooperative intermolecular interactions driven by π stacking.

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A macrocyclic receptor molecule containing two viologen species connected by conjugated terphenyl groups has been designed and synthesised. The single-crystal X-ray structure shows that the two viologen residues have a transannular NN separation of ca. 7.

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We recently reported that the hydroxyiminoethanone derivative, (E)-OXM, behaves as a highly selective COX-1 inhibitor (COX-1 SI = 833), and also an interesting scaffold with unique characteristics. In the current study, a comprehensive crystallographic and computational study was performed to elucidate its conformational stability and pharmacological activity. Its conformational energy was studied at the B3LYP/6-311G** level of theory and compared to the single-crystal X-ray diffraction data.

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Intralocus sexual conflict generates a cost to mate choice: high-fitness partners transmit genetic variation that confers lower fitness to offspring of the opposite sex. Our earlier work in the fruit fly, Drosophila melanogaster, revealed that these indirect genetic costs were sufficient to reverse potential "good genes" benefits of sexual selection. However, mate choice can also confer direct fitness benefits by inducing larger numbers of progeny.

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In this paper, we report the synthesis and healing ability of a non-cytotoxic supramolecular polyurethane network whose mechanical properties can be recovered efficiently (>99%) at the temperature of the human body (37 °C). Rheological analysis revealed an acceleration in the drop of the storage modulus above 37 °C, on account of the dissociation of the supramolecular polyurethane network, and this decrease in viscosity enables the efficient recovery of the mechanical properties. Microscopic and mechanical characterisation has shown that this material is able to recover mechanical properties across a damage site with minimal contact required between the interfaces and also demonstrated that the mechanical properties improved when compared to other low temperature healing elastomers or gel-like materials.

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Nickel cyanide is a layered material showing markedly anisotropic behaviour. High-pressure neutron diffraction measurements show that at pressures up to 20.1 kbar, compressibility is much higher in the direction perpendicular to the layers, c, than in the plane of the strongly chemically bonded metal-cyanide sheets.

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Two recent studies provide provocative experimental findings about the potential influence of kin recognition and cooperation on the level of sexual conflict in Drosophila melanogaster. In both studies, male fruit flies apparently curbed their mate-harming behaviours in the presence of a few familiar or related males, suggesting some form of cooperation mediated by kin selection. In one study, the reduction in agonistic behaviour by brothers apparently rendered them vulnerable to dramatic loss of paternity share when competing with an unrelated male.

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Layered copper-nickel cyanide, CuNi(CN)4, a 2-D negative thermal expansion material, is one of a series of copper(ii)-containing cyanides derived from Ni(CN)2. In CuNi(CN)4, unlike in Ni(CN)2, the cyanide groups are ordered generating square-planar Ni(CN)4 and Cu(NC)4 units. The adoption of square-planar geometry by Cu(ii) in an extended solid is very unusual.

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There is concern that waste waters containing manufactured metal nanoparticles (NPs) originating from consumer goods, will find their way into streams and larger water bodies. Aquatic invertebrates could be vulnerable to such pollution, and here we have used fruit flies, Drosophila melanogaster, as a model invertebrate, to test for the effect of NPs on fitness. Both copper NP and microparticle (MP)-containing medium slowed development, reduced adult longevity and decreased sperm competition.

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The evolutionary theory of aging predicts that longevity will decline via drift or age-specific tradeoffs when selection favors early life fitness. Many Drosophila melanogaster populations continually terminated at young adult ages retain surprisingly long postselection lifespans. We compiled three decades of longevity data from the Ives population, demonstrating that postselective longevity was both substantial (30 days) and temporally stable over this period.

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In two fruit fly species, in vivo observations of competing sperm reveal how differences in sperm size, female behavior and reproductive architecture promote retention of same-species sperm. Sexual selection continues after mating and may play an important role in speciation.

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Neutron diffraction at 11.4 and 295 K and solid-state (67)Zn NMR are used to determine both the local and the average structures in the disordered, negative thermal expansion (NTE) material, Zn(CN)2. Solid-state NMR not only confirms that there is head-to-tail disorder of the C≡N groups present in the solid, but yields information about the relative abundances of the different Zn(CN)4–n(NC)n tetrahedral species, which do not follow a simple binomial distribution.

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When males and females have different fitness optima for the same trait but share loci, intralocus sexual conflict is likely to occur. Epigenetic mechanisms such as genomic imprinting (in which expression is altered according to parent-of-origin) and sex-specific maternal effects have been suggested as ways by which this conflict can be resolved. However these ideas have not yet been empirically tested.

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Explaining the maintenance of genetic variation in characters associated with Darwinian fitness is a preoccupation of evolutionary biologists. Spatial or temporal variation in the environment can certainly promote polymorphism, yet even populations of 'model organisms', like fruit flies, kept on invariant protocols for hundreds of generations in the laboratory often show fitness variation that exceeds what would be expected from the input of new mutations alone. Such observations suggest either complexities of selection or of genetic architecture, and offer a powerful tool for the study of mechanisms that promote stable polymorphism.

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