44,665 research outputs found
Cobalt(III), zinc(II), cadmium(II) and palladium(II) complexes with the hydrolysed and non-hydrolysed condensation products of 2-acetylpyridine with ethyl hydrazinoacetate: X-ray structure analysis of mer-bis{(E)-2-[N '-(1-pyridin-2-yl-ethylidene)hydrazin
No full textFour Co(III), Zn(II), Pd(II) and Cd(II) complexes with ligands derived in situ from acetylpyridine and ethyl hydrazinoacetate or hydrolysed ethyl hydrazinoacetate were prepared. An X-ray structural analysis showed that the Co(III) complex is octahedral with two tridentate (E)-2-[N'-(1-pyridin-2-yl-ethylidene) hydrazino] acetate (apha) ligands, each forming two five-membered rings with the metal ion. In the tetrahedral Zn(II) complex, only a single apha ligand was coordinated, in the same way as that in the Co(III) complex. In the case of the tetrahedral Cd(II) complex the non-hydrolysed form of (E)-2-[N'-(1-pyridin2-yl-ethylidene)hydrazino]acetic acid ethyl ester (aphaoet) coordinated as a bidentate and the two remaining coordination sites were occupied by Cl- and CH3COO- ions. In addition, the square-planar neutral Pd(II) complex was synthesized, having the same bidentate as in the Cd(II) complex and two Cl- ions in the remaining coordination sites. Due to their being diamagnetic, all four complexes were characterized by H-1-NMR and C-13-NMR spectroscopy
Laguerre geometry of hypersurfaces in R-n
No full textLaguerre geometry of surfaces in R-3 is given in the book of Blaschke [Vorlesungen uber Differentialgeometrie, Springer, Berlin Heidelberg New York (1929)], and has been studied by Musso and Nicolodi [Trans. Am. Math. soc. 348, 4321-4337 (1996); Abh. Math. Sem. Univ. Hamburg 69, 123-138 (1999); Int. J. Math. 11(7), 911-924 (2000)], Palmer [Remarks on a variation problem in Laguerre geometry. Rendiconti di Mathematica, Serie VII, Roma, vol. 19, pp. 281-293 (1999)] and other authors. In this paper we study Laguerre differential geometry of hypersurfaces in R-n. For any umbilical free hypersurface x:M -> R-n with non-zero principal curvatures we define a Laguerre invariant metric g on M and a Laguerre invariant self-adjoint operator S:TM -> TM, and show that {g,S} is a complete Laguerre invariant system for hypersurfaces in R-n with >= 4. We calculate the Euler-Lagrange equation for the Laguerre volume functional of Laguerre metric by using Laguerre invariants. Using the Euclidean space R-n, the semi-Euclidean space R-1(n) and the degenerate space R-0(n) we define three Laguerre space forms URn, UR1n and UR0n and define the Laguerre embeddings URn1 -> URn and UR0n -> URn, analogously to what happens in the Moebius geometry where we have Moebius space forms S-n, H-n and R-n (spaces of constant curvature) and conformal embeddings H-n -> S-n and R-n -> S-n[cf. Liu et al. in Tohoku Math. J. 53, 553-569 (2001) and Wang in Manuscr. Math. 96, 517-534 (1998)]. Using these Laguerre embeddings we can unify the Laguerre geometry of hypersurfaces in R-n, R-1(n) and R-0(n). As an example we show that minimal surfaces in R-1(3) or R-0(3) are Laguerre minimal in R-3.MathematicsSCI(E)0ARTICLE173-9512
Synthesis, structure and cytotoxic activity evaluation of a dinuclear complex of Cd(II) with N ',N '(2)-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide
No full textA new dinuclear complex of Cd(II) with N',N'(2)-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide (H2L) was synthesized and its crystal structure determined. The basic structural unit of the complex is the binuclear [Cd-2(H2O)(2)(H2L)(2)](4+) cation, where each cadmium atom is heptacoordinated by two tridentate H2L ligands, by means of the NNO chelating system, and one water molecule. A 12-membered macrocycle is defined at the core of the binuclear cation. The complex showed a pronounced cytotoxic activity to murine melanoma B16 cells and human cervical cancer HeLa cells. (c) 2007 Elsevier B.V. All rights reserved
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
Synthesis, characterization and biological activity evaluation of Pt(II), Pd(II), Co(III) and Ni(II) complexes with N-heteroaromatic selenosemicarbazones
No full textFive new complexes of Pt(II), Pd(II), Co(III) and Ni(II) with 2-pyridine(quinoline) carboxaldehyde selenose-micarbazones were synthesized and characterized. Crystal structures of Pt(II) complex with the pyridine derivative and Co(III) complex with the quinoline derivative were determined. In all complexes the ligands were coordinated through N(2)Se donor atom set forming either square-planar (Pt, Pd) or octahedral (Co, Ni) geometry. All complexes showed biological activity. (C) 2009 Elsevier B. V. All rights reserved
Challenge in R&D Management : Tata Steel A Case Study
No full textThe purpose of R&D management is to promote innovation as
well as wealth creation. The paper traces the history of R&D managementhow it has changed from the first generation when only innovation was the main objective to the fifth generation where IT plays an important role. It is now necessary to understand the needs of market for conducting worthwhile research. The author shares his experience of R&D management at Tata Steel. The experience shows that by adopting judicious R&D strategy it is possible to face the challenges of reconciling innovation with wealth
creation is possible by a judicious R&D strategy
Selenotriapine – An isostere of the most studied thiosemicarbazone with pronounced pro-apoptotic activity, low toxicity and ability to challenge phenotype reprogramming of 3-D mammary adenocarcinoma tumors
No full textTriapine, the most studied α-N-heterocyclic thiosemicarbazone, revealed potent activity against advanced leukemia, but was ineffective against a variety of solid tumors. Moreover, methemoglobinemia, which is a side effect of triapine administration, may limits all clinical application. To enhance anticancer activity and reduce side effects, we applied an isosteric replacement of sulfur to selenium atom was performed by synthesis and characterization of selenium triapine analog, 3-aminopyridine-2-carboxaldehyde selenosemicarbazone (selenotriapine). Compared to triapine, selenotriapine revealed superior pro-apoptotic activity with activation of intrinsic apoptotic pathway in both human monocytic leukemia (THP-1) and mammary adenocarcinoma (MCF-7) cell lines. For MCF-7 2-D cultures, selenotriapine induced notable increase in mitochondrial superoxide radical generation and dissipation of mitochondrial transmembrane potential. A significant delay in growth of MCF-7 spheroids (3-D culture) was accompanied by phenotypic stem cell reprogramming (Oct-4 expression). Additionally, selenotriapine demonstrated a very low toxicity profile as compared to triapine, confirmed over alleviated extent of methemoglobin formation and higher IC50 value in brine shrimp cytotoxicity assay
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