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The integrins α v β 3 and α v β 5 and the membrane-spanning surface protein aminopeptidase-N (APN) are highly expressed in tumor-induced angiogenesis, making them attractive targets for therapeutic intervention. Both integrins and APN recognize a broad range of peptides containing RGD (ArgGly-Asp) and NGR (Asn-Gly-Arg) motifs, respectively. Here, we describe the design, synthesis, and characterization of a series of mono-and difunctionalized platinum(IV) complexes in which a conjugated peptide motif, containing either RGD, CRGDC, (RGDfK)c or NGR, is appended as a 'tumor-homing device' to target tumor endothelial cells selectively over healthy cells. Platinum(IV)-peptide complexes with non-specific amino acids or peptide moieties were prepared as controls. Concentration-response curves of these compounds were evaluated against primary proliferating endothelial cells and tumor cell lines and compared to those of cisplatin, a well-described platinumbased chemotherapeutic agent. The Pt(IV)-RGD conjugates were highly and specifically cytotoxic to α v β 3 and α v β 5 containing cell lines, approaching the activity of cisplatin. The Pt(IV)-NGR complexes were less active than Pt(IV)-RGD-containing compounds but more active than nonspecific Pt-peptide controls. Integrin α v β 3 mediated, at least in part, the anti-proliferative effect of an Pt(IV)-RGD conjugate, as demonstrated by a decreased inhibitory response when endothelial cells were either (1) incubated with an excess of α v β 3 /α v β 3 -specific RGD pentapeptides, or (2) transfected with RNAi for β 3 , but not β 1 , integrins. These results suggest a rational approach to improved chemotherapy with Pt(IV)-peptide conjugates by selective drug delivery to the tumor compartment.

This is a continuation of our earlier work where we constructed a phenomenologically motivated effective action of the boundary gauge theory at finite temperature and finite gauge coupling on S 3 × S 1 . In this paper, we argue that this effective action qualitatively reproduces the gauge theory representing various bulk phases of R-charged black hole with GaussBonnet correction. We analyze the system both in canonical and grand canonical ensemble.

We find solutions of 11-dimensional supergravity for M5-branes wrapped on Riemann surfaces. These solutions preserve N = 2 fourdimensional supersymmetry. They are dual to N = 2 gauge theories, including non-conformal field theories. We work out the case of N = 2 Yang-Mills in detail.

For Abstract see ChemInform Abstract in Full Text.

The copper coordination chemistry of two phthalazine-based ligands of differing steric bulk was investigated. A family of dinuclear complexes were prepared from reactions of [Cu(2)(bdptz)(MeCN)(2)](OTf)(2), 1(OTf)(2), where bdptz = 1,4-bis(2,2'-dipyridylmethyl)phthalazine. Treatment of 1(OTf)(2) with NaO(2)CCH(3) afforded the class I mixed-valent compound [Cu(2)(bdptz)(2)](OTf)(3), 2(OTf)(3), by disproportionation of Cu(I). Compound 2(OTf)(3) displays an electron paramagnetic resonance spectrum, with g( parallel ) = 2.25 (A( parallel ) = 169 G) and g( perpendicular ) = 2.06, and exhibits a reversible redox wave at -452 mV versus Cp(2)Fe(+)/Cp(2)Fe. The complex [Cu(2)(bdptz)(micro-OH)(MeCN)(2)](OTf)(3), 3(OTf)(3), was prepared by chemical oxidation of 1 with AgOTf, and exposure of 1 to dioxygen afforded [Cu(2)(bdptz)(micro-OH)(2)](2)(OTs)(4), 4(OTs)(4), which can also be obtained directly from [Cu(H(2)O)(6)](OTs)(2). In compound [Cu(2)(bdptz)(micro-vpy)](OTf)(2), 5(OTf)(2), where vpy = 2-vinylpyridine, the vpy ligand bridges the two Cu(I) centers by using both its pyridine nitrogen and the olefin as donor functionalities. The sterically hindered compounds [Cu(2)(Ph(4)bdptz)(MeCN)(2)](OTf)(2), 6(OTf)(2), and [Cu(2)(Ph(4)bdptz)(micro-O(2)CCH(3))](OTf), 7(OTf), were also synthesized, where Ph(4)bdptz = 1,4-bis[bis(6-phenyl-2-pyridyl)methyl]phthalazine. Complexes 1-7 were characterized structurally by X-ray crystallography. In 6 and 7, the four phenyl rings form a hydrophobic pocket that houses the acetonitrile and acetate ligands. Complex 6 displays two reversible redox waves with E(1/2) values of +41 and +516 mV versus Cp(2)Fe(+)/Cp(2)Fe. Analysis of oxygenated solutions of 6 by electrospray ionization mass spectrometry reveals probable aromatic hydroxylation of the Ph(4)bdptz ligand. The different chemical and electrochemical behavior of 1 versus 6 highlights the influence of a hydrophobic binding pocket on the stability and reactivity of the dicopper(I) centers.

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Abstract.We present a comparative study of the magnetic and electrical properties of polycrystalline and nanocrystalline Y 2 Ir 2 O 7 , the latter prepared using a new chemical route. We find that reduction in particle size leads to enhanced ferromagnetism and orders of magnitude enhancement of electrical conductivity in the nanocrystalline sample. Based on X-ray photoelectron spectroscopy and X-ray absorption near edge structure spectroscopy results, the phenomenon is attributed to the increased fraction of Ir 5+ and the resulting increase in double exchange interaction along with the weakening of spin-orbit coupling strength in the nanocrystalline sample compared to the bulk.