344 research outputs found
Peeter Espak, The God Enki in Sumerian Royal Ideology and Mythology (Philippika 87)
P. Espak’s book The God Enki is a daring attempt to compile and interpret the available Sumerian sources pertaining to the all-important figure of the god Enki/Ea and related deities. The author focuses on two main bodies of evidence: royal inscriptions and mythological texts. References to other sources of information regarding ancient beliefs and worship, such as archaeology, onomastics, religious texts and wisdom literature, appear scattered across the volume where deemed relevant to the a..
Morphological evolution of pulsed laser deposited ZrO2 thin films
Morphological evolution of ZrO2 thin films deposited during pulsed laser deposition of Zr in O2
atmosphere has been experimentally studied at two different film deposition temperatures, 300 and
873 K. The roughness exponent, , the growth exponent, , the coarsening exponent, 1/z, and the
exponent defining the evolution of the characteristic wavelength of the surface, p, for depositions at
300 K amounted to = 1.00.1, = 0.40.1, 1/z= 0.340.03, and p= 0.490.03, whereas for
depositions carried out at 873 K amounted to = 0.30.3, = 0.40.2, and 1/z= 0.00.2.
Experimental error becomes important due to the flat morphology of the films inherent to the
deposition technique. The change in the surface topography with the film temperature has been
studied with the help of a simple Monte Carlo model which indicates the existence of two different
growth regimes: a shadowing dominated growth, occurring at low temperatures, characterized by
calculated values = 1.000.04, = 0.500.04, p= 0.460.01, and 1/z= 0.350.02 and a
diffusion dominated growth that takes place at high temperatures as well as at low deposition rates,
characterized by calculated values = 0.150.08, = 0.330.04, and 1/z= 0.330.07. The good
agreement obtained between the experimental and simulated parameters is discussed within the
frame of the general characteristics of the deposition method.Universidad Nacional Autónoma de México-PAPIIT-IN107808Consejo Nacional de Ciencia y Tecnología de México-CONACyT-50203-FMinisterio de Ciencia, Innovación y Universidades de España-MAT 2007-65764, PIE 200960I132 y CONSOLIDER INGENIO 2010-CSD2008-00023Junta de Andalucía-TEP2275 y P07-FQM-0329
Iron-catalyzed stereoselective C–H alkylation for simultaneous construction of C–N axial and C -central chirality
The assembly of chiral molecules with multiple stereogenic elements is challenging, and, despite of indisputable advances, largely limited to toxic, cost-intensive and precious metal catalysts. In sharp contrast, we herein disclose a versatile C–H alkylation using a non-toxic, low-cost iron catalyst for the synthesis of substituted indoles with two chiral elements. The key for achieving excellent diastereo- and enantioselectivity was substitution on a chiral N-heterocyclic carbene ligand providing steric hindrance and extra represented by noncovalent interaction for the concomitant generation of C–N axial chirality and C-stereogenic center. Experimental and computational mechanistic studies have unraveled the origin of the catalytic efficacy and stereoselectivity
Cleavage Requirements for Activation of Factor V by Factor Xa
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65728/1/j.1432-1033.1997.00012.x.pd
Rhodium(III)-Catalyzed Dearomatizing (3+2) Annulation of 2-Alkenylphenols and Alkynes
Appropriately substituted 2-alkenylphenols undergo a mild formal [3C+2C] cycloaddition with alkynes when treated with a Rh(III) catalyst and an oxidant. The reaction, which involves the cleavage of the terminal C–H bond of the alkenyl moiety and the dearomatization of the phenol ring, provides a versatile and efficient approach to highly appealing spirocyclic skeletons and occurs with high selectivityWe thank the financial support provided by the Spanish Grants SAF2010-20822-C02 and CSD2007-00006 Consolider Ingenio 2010, the Xunta de Galicia Grants GR2013-041 and EM2013/036, the ERDF, and the European Research Council (Advanced Grant No. 340055). M.G. thanks Xunta de Galicia for a Parga Pondal contractS
Allylic Oxidation of Alkenes Catalyzed by a Copper−Aluminum Mixed Oxide
A strategy for the allylic oxidation of cyclic alkenes with a copper−aluminum mixed oxide as catalyst is presented. The reaction involves the treatment of an alkene with a carboxylic acid employing tert-butyl hydroperoxide as the oxidant. In all cases, the corresponding allylic esters are obtained. When L-proline is employed, the allylic alcohol or ketone is obtained. The oxidation of cyclohexene and valencene has been optimized by design of experiments (DoE) statistical methodology
A steric tethering approach enables palladium-catalysed C-H activation of primary amino alcohols.
Aliphatic primary amines are a class of chemical feedstock essential to the synthesis of higher-order nitrogen-containing molecules, commonly found in biologically active compounds and pharmaceutical agents. New methods for the construction of complex amines remain a continuous challenge to synthetic chemists. Here, we outline a general palladium-catalysed strategy for the functionalization of aliphatic C-H bonds within amino alcohols, an important class of small molecule. Central to this strategy is the temporary conversion of catalytically incompatible primary amino alcohols into hindered secondary amines that are capable of undergoing a sterically promoted palladium-catalysed C-H activation. Furthermore, a hydrogen bond between amine and catalyst intensifies interactions around the palladium and orients the aliphatic amine substituents in an ideal geometry for C-H activation. This catalytic method directly transforms simple, easily accessible amines into highly substituted, functionally concentrated and structurally diverse products, and can streamline the synthesis of biologically important amine-containing molecules.We are grateful to the Marie Curie Foundation (D.P. & J.C.), EPSRC (T.W.G.), the ERC (V.D.), and the ERC and EPSRC for Fellowships (M.J.G.). We are grateful to Adam Smalley for DFT calculations and Yohei Shimidzu for assistance with optimization of the C–H acetoxylation reaction. Mass spectrometry data was acquired at the EPSRC UK National Mass Spectrometry Facility at Swansea University. The authors declare no competing financial interests.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/nchem.236
Modular design of SPIRO-OMeTAD analogues as hole transport materials in solar cells
We predict the ionisation potentials of the hole-conducting material SPIRO-OMeTAD and twelve methoxy isomers and polymethoxy derivatives. Based on electronic and economic factors, we identify the optimal compounds for application as p-type hole-selective contacts in hybrid halide perovskite solar cells
Plasma and cellular fibronectin: distinct and independent functions during tissue repair
Fibronectin (FN) is a ubiquitous extracellular matrix (ECM) glycoprotein that plays vital roles during tissue repair. The plasma form of FN circulates in the blood, and upon tissue injury, is incorporated into fibrin clots to exert effects on platelet function and to mediate hemostasis. Cellular FN is then synthesized and assembled by cells as they migrate into the clot to reconstitute damaged tissue. The assembly of FN into a complex three-dimensional matrix during physiological repair plays a key role not only as a structural scaffold, but also as a regulator of cell function during this stage of tissue repair. FN fibrillogenesis is a complex, stepwise process that is strictly regulated by a multitude of factors. During fibrosis, there is excessive deposition of ECM, of which FN is one of the major components. Aberrant FN-matrix assembly is a major contributing factor to the switch from normal tissue repair to misregulated fibrosis. Understanding the mechanisms involved in FN assembly and how these interplay with cellular, fibrotic and immune responses may reveal targets for the future development of therapies to regulate aberrant tissue-repair processes
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