Ability of Group IVB metallocene polyethers containing dienestrol to arrest the growth of selected cancer cell lines

<p>Abstract</p> <p>Background</p> <p>Monomeric Group IVB (Ti, Zr and Hf) metallocenes represent a new class of antitumor compounds. There is literature on the general biological activities of some organotin compounds. Unfortunately, there is little information with respect to the molecular level activity of these organotin compounds. We recently started focusing on the anti-cancer activity of organotin polymers that we had made for other purposes and as part of our platinum anti-cancer effort.</p> <p>Methods</p> <p>For this study, we synthesized a new series of metallocene-containing compounds coupling the metallocene unit with dienestrol, a synthetic, nonsteroidal estrogen. This is part of our effort to couple known moieties that offer antitumor activity with biologically active units hoping to increase the biological activity of the combination. The materials were confirmed to be polymeric using light scattering photometry and the structural repeat unit was verified employing matrix assisted laser desorption ionization mass spectrometry and infrared spectroscopy results.</p> <p>Results</p> <p>The polymers demonstrated the ability to suppress the growth of a series of tumor cell lines originating from breast, colon, prostrate, and lung cancers at concentrations generally lower than those required for inhibition of cell growth by the commonly used antitumor drug cisplatin.</p> <p>Conclusion</p> <p>These drugs show great promise in vitro against a number of cancer cell lines and due to their polymeric nature will most likely be less toxic than currently used metal-containing drugs such as cisplatin. These drugs also offer several addition positive aspects. First, the reactants are commercially available so that additional synthetic steps are not needed. Second, synthesis of the polymer is rapid, occurring within about 15 seconds. Third, the interfacial synthetic system is already industrially employed in the synthesis of aromatic nylons and polycarbonates. Thus, the ability to synthesize large amounts of the drugs is straight forward.</p

Identifying Elements of \u3cem\u3eKinder- und Jugendliteratur\u3c/em\u3e

Kinder- und Jugendliteratur, children’s literature written for the purpose of teaching or entertaining young people, has been present in German literature since the Middle Ages. This genre has changed as German literature progressed, reflecting the developments of each era, including such periods as the Romantic, the Biedermeier, Realism, Modernism and Postmodernism. As such, we examined individual works of German Kinder- und Jugendliteratur for the purpose of identifying distinctive features which situate them within children’s literature as well as in the respective historical genre. The works examined were Nußknacker und Mausekönig (1816) by E. T. A. Hoffmann, Emil und die Detektive (1929) by Erich Kästner, Försters Pucki (1935) by Madge Trott, Jan und das Wildpferd (1957) by Heinrich Denneborg, Die Wolke (1987) by Gudrun Pausewang, and Tintenherz (2003) by Cornelia Funke. We present our findings in the form of a Wimmelbuch, a typical form of German Kinder- und Jugendliteratur made popular during the Biedermeier period of the mid-1800s

A diagrammatic view of the equals sign: arithmetical equivalence as a means, not an end

It is recommended in the mathematics education literature that pupils be presented with equality statements that can be assessed for numerical balance by attending to notational structure rather than computation. I describe an alternative, diagrammatic approach in which pupils do not assess statements but instead use them to make substitutions of notation. I report on two trials of a computer-based task conducted with pairs of pupils and highlight two findings. First, the pupils found it useful to articulate the distinct substitutive effects of commutative (‘swap’, ‘switch’) and partitional (‘split’, ‘separate’) statements when working on the task. Secondly, the pupils did not notice that some of the statements presented were in fact false, which suggests their substituting activities were independent of numerical equivalence conceptions. This demonstrates that making substitutions offers task designers a mathematical utility for equality statements that is distinct from, but complementary to, assessing numerical balance

Development of intuitive rules: Evaluating the application of the dual-system framework to understanding children's intuitive reasoning

This is an author-created version of this article. The original source of publication is Psychon Bull Rev. 2006 Dec;13(6):935-53 The final publication is available at www.springerlink.com Published version: http://dx.doi.org/10.3758/BF0321390

Making Associativity Operational

The purpose of this paper is to propose an operational idea for developing algebraic thinking in the absence of alphanumeric symbols. The paper reports on a design experiment encouraging preschool children to use the associative property algebraically. We describe the theoretical basis of the design, the tasks used, and examples of algebraic thinking in 5–6-year-old children. Theoretically, the paper makes a critical distinction between operational and structural meanings of the notion of equality. We argue that mathematical thinking involving equality among young learners can comprise both an operational and a structural conception and that the operational conception has a side that is productively linked to the structural conception. Using carefully designed hands-on tasks, the crux of the paper is the realization of algebraic thinking (in verbal mathematics) as operationally experienced in the ability to transform one number structure, with a quantity that is subject to change, into another through equality-preserving transformations

Corrosive-Abrasive Wear Induced by Soot in Boundary Lubrication Regime

Soot is known to induce high wear in engine components. The mechanism by which soot induces wear is not well understood. Although several mechanisms have been suggested, there is still no consensus. This study aims to investigate the most likely mechanism responsible for soot-induced wear in the boundary lubrication regime. Results from this study have shown that previously suggested mechanisms such as abrasion and additive adsorption do not fully explain the high wear observed when soot is present. Based on the results obtained from tests conducted at varying temperature and soot levels, it has been proven that the corrosive–abrasive mechanism was responsible for high wear that occurred in boundary lubrication conditions

Significant process of change for elementary teachers to foster functional thinking

The purpose of this study was to explore a professional development program that involved 15 teachers. Functional thinking was used as a centerpiece of the program for work with teachers of Grades 1-5 during 6 months of the study. We used the concern-based adaptation model (CBAM) as a methodology to track the process of change of teachers and to understand the trajectories through which teachers may progress. Two questions guided the investigations: 1. How does implementation of the professional development program focused on functional thinking impact teachers' concerns? 2. How did teachers' practice change due to the implementation of the innovation program? The result of the study showed effectiveness of process of change in teachers, both in stages of concerns and level of use of the innovation

Sequence Comparisons of Odorant Receptors among Tortricid Moths Reveal Different Rates of Molecular Evolution among Family Members

In insects, odorant receptors detect volatile cues involved in behaviours such as mate recognition, food location and oviposition. We have investigated the evolution of three odorant receptors from five species within the moth genera Ctenopseustis and Planotrotrix, family Tortricidae, which fall into distinct clades within the odorant receptor multigene family. One receptor is the orthologue of the co-receptor Or83b, now known as Orco (OR2), and encodes the obligate ion channel subunit of the receptor complex. In comparison, the other two receptors, OR1 and OR3, are ligand-binding receptor subunits, activated by volatile compounds produced by plants - methyl salicylate and citral, respectively. Rates of sequence evolution at non-synonymous sites were significantly higher in OR1 compared with OR2 and OR3. Within the dataset OR1 contains 109 variable amino acid positions that are distributed evenly across the entire protein including transmembrane helices, loop regions and termini, while OR2 and OR3 contain 18 and 16 variable sites, respectively. OR2 shows a high level of amino acid conservation as expected due to its essential role in odour detection; however we found unexpected differences in the rate of evolution between two ligand-binding odorant receptors, OR1 and OR3. OR3 shows high sequence conservation suggestive of a conserved role in odour reception, whereas the higher rate of evolution observed in OR1, particularly at non-synonymous sites, may be suggestive of relaxed constraint, perhaps associated with the loss of an ancestral role in sex pheromone reception