Queensland Agricultural Journal Volume 13 Parts 1-6 July to December 1903

General Index Vol 13 Parts 1-6, pages 1-81

Stereospecific photodimerization of coumarins in crystalline inclusion complexes. Molecular and crystal structure of 1:2 complex of (S,S)-(-)-1,6-bis(o-chlorophenyl)-1,6-diphenyl-hexa-2,4-diyne-1,6-diol and coumarin

Proximity of molecules is a crucial factor in many solid- state photochemical processes.'S2 The biomolecular photodimerization reactions in the solid state depend on the relative geometry of reactant molecules in the crystal lattice with center-to-center distance of nearest neighbor double bonds of the order of ca. 4 A. This fact emanates from the incisive studies of Schmidt and Cohen.2 One of the two approaches to achieve this distance requirement is the so-called "Crystal-Engineering" of structures, which essentially involves the introduction of certain functional groups that display in-plane interstacking interactions (Cl...Cl, C-He-0, etc.) in the crystal The chloro group is by far the most successful in promoting the /3- packing m ~ d e ,th~o,u~gh recent studies have shown its limitations? Another approach involves the use of constrained media in which the reactants could hopefully be aligned.

Synthesis of two designed hairpin peptides on a newly developed 1,6-hexanediol diacrylate (HDODA)-crosslinked polystyrene resin

Synthesis of two designed hairpin peptides on 1,6-hexanediol diacrylate crosslinked polystyrene support using the standard solid phase methodology is described. Both the peptides are obtained in high yield and purity. The new polymeric system is an ideal support for the synthesis of hairpin peptides, which is a very difficult task by the solid phase method.

Nanostructuring of p- and n-type skutterudites reaching figures of merit of approximately 1.3 and 1.6, respectively

Thermoelectric (TE) conversion of waste heat into useful electricity demands optimized thermal and electrical transport in the leg material over a wide temperature range. In order to gain a reasonably high figure of merit (ZT) as well as high thermal electric conversion efficiency, various conditions of the starting material were studied: industrially produced skutterudite powders of p-type DDy(Fe1-xCox)(4)Sb-12 (DD: didymium) and n-type (Mm, Sm)(y)Co4Sb12 (Mm: mischmetal) were used. After a rather fast reaction-melting technique, the bulk was crushed and sieved with various strainers in order to obtain particles below the respective mesh sizes, followed by ball-milling under three different conditions. The dependence of the TE properties (after hot pressing) on the micro/nanosized particles, grains and crystallites was investigated. Optimized conditions resulted in an increase of ZT for bulk material to current record-high values: from ZT similar to 1.1 to ZT similar to 1.3 at 775 K for p-type and from ZT similar to 1.0 to ZT similar to 1.6 at 800 K for n-type, resulting in respective efficiencies (300-850 K) of eta > 13% and eta similar to 16%. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Intertextualidad e intersemiosis en Macanudo (1- 6) de Liniers

Introducción: “A veces me gusta tomarme un tiempo para observar el mundo y ver lo increíble y lo frágil que es todo”, “Si te conocés desde chico con alguien, entonces podés ser chico cuando quieras”, “Mi nación es cualquier lugar donde alguien se abrace”. Expresiones como éstas cautivan a los lectores por su profundidad, su delicadeza, su capacidad de observación y de síntesis para nombrar los grandes temas de la existencia. La elección de cada palabra y su orden en la frase están cuidadosamente sopesados; hay un uso peculiar de los adjetivos y las estructuras sintácticas que contribuye a la densidad del discurso. Estos pequeños textos lingüísticos nos sitúan, por lo tanto, frente a lo que Roman Jakobson llamó la “función poética” del lenguaje. Este tipo de frases abundan en Macanudo, la tira creada por Ricardo “Liniers” Siri que, desde el año 2002, se publica diariamente en la última página de la sección Espectáculos del periódico argentino La Nación. La tira ha sido tan bien aceptada por el público que ya lleva una década en el diario y su autor ha reunido ese material en diez libros. Además de su poesía verbal, son muchos los factores que hacen de Macanudo una historieta especial, diferente de la mayoría. Por empezar, se trata de una tira que aloja las historias y ocurrencias de múltiples personajes, algunos fijos, otros esporádicos y unos cuantos que tan sólo viven un día. Los dibujos de Liniers complementan la escritura reforzando la configuración de un universo propio, dotado de sensibilidad, humor y ternura. En su espacio tienen lugar la reflexión filosófica y sociopolítica, así como cuestiones relacionadas con los vínculos humanos, la creación artística y, especialmente, el rol que ocupan el arte y la industria cultural en nuestra vida cotidiana...

Structural and mechanistic study of monoalkyl diazenes. Synthesis, characterization, and reactivity of 1,6-didehydro[10]annulene

Methodology for the preparation of allenes from propargylic hydrazine precursors under mild conditions is described. Oxidation of the propargylic hydrazines, which can be readily prepared from propargylic alcohols, with either of two azo oxidants, diethyl azodicarboxylate (DEAD) or 4-methyl 1,2-triazoline-3,5-dione (MTAD), effects conversion to the allenes, presumably via sigmatropic rearrangement of a monoalkyl diazene intermediate. This rearrangement is demonstrated to proceed with essentially complete stereospecificity. The application of this methodology to the preparation of other allenes, including two that are notable for their reactivity and thermal instability, is also described.

The structural and mechanistic study of a monoalkyl diazene intermediate in the oxidative transformation of propargylic hydrazines to allenes is described. The use of long-range heteronuclear NMR coupling constants for assigning monoalkyl diazene stereochemistry (E vs Z) is also discussed. Evidence is presented that all known monoalkyl diazenes are the E isomers, and the erroneous assignment of stereochemistry in the previous report of the preparation of (Z)-phenyldiazene is discussed.

The synthesis, characterization, and reactivity of 1,6-didehydro[10]annulene are described. This molecule has been recognized as an interesting synthetic target for over 40 years and represents the intersection of two sets of extensively studied molecules: nonbenzenoid aromatic compounds and molecules containing sterically compressed π-systems.The formation of 1,5-dehydronaphthalene from 1 ,6-didehydro[10]annulene is believed to be the prototype for cycloaromatizations that produce 1,4-dehydroaromatic species with the radical centers disposed anti about the newly formed single bond. The aromaticity of this annulene and the facility of its cycloaromatization are also analyzed.

Observations of 1-6 MeV Jovian electrons at 1 AU and a study of their propagation

The 1-6 MeV electron flux at 1 AU has been measured for the time period October 1972 to December 1977 by the Caltech Electron/Isotope Spectrometers on the IMP-7 and IMP-8 satellites. The non-solar interplanetary electron flux reported here covered parts of five synodic periods. The 88 Jovian increases identified in these five synodic periods were classified by their time profiles. The fall time profiles were consistent with an exponential fall with τ ≈ 4-9 days. The rise time profiles displayed a systematic variation over the synodic period. Exponential rise time profiles with τ ≈ 1-3 days tended to occur in the time period before nominal connection, diffusive profiles predicted by the convection-diffusion model around nominal connection, and abrupt profiles after nominal connection.

The times of enhancements in the magnetic field, │B│, at 1 AU showed a better correlation than corotating interaction regions (CIR's) with Jovian increases and other changes in the electron flux at 1 AU, suggesting that │B│ enhancements indicate the times that barriers to electron propagation pass Earth. Time sequences of the increases and decreases in the electron flux at 1 AU were qualitatively modeled by using the times that CIR's passed Jupiter and the times that │B│ enhancements passed Earth.

The electron data observed at 1 AU were modeled by using a convection-diffusion model of Jovian electron propagation. The synodic envelope formed by the maxima of the Jovian increases was modeled by the envelope formed by the predicted intensities at a time less than that needed to reach equilibrium. Even though the envelope shape calculated in this way was similar to the observed envelope, the required diffusion coefficients were not consistent with a diffusive process.

Three Jovian electron increases at 1 AU for the 1974 synodic period were fit with rise time profiles calculated from the convection-diffusion model. For the fits without an ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 1.0 - 2.5 x 10²¹ cm²/sec and k_y = 1.6 - 2.0 x 10²² cm²/sec. For the fits that included the ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 0.4 - 1.0 x 10²¹ cm²/sec and k_y = 0.8 - 1.3 x 10²² cm²/sec.

Infrared (1.2-1.6 mu m) luminescence in Yb, Cr : YAG with 940 nm diode pumping

Infrared (1.2-1.6 mum) luminescence in a yttrium aluminium garnet (YAG) crystal, co-doped with Yb (10 at.%) and Cr (0.05 at.%) ions, was investigated under CW laser diode pumping (lambda = 940 nm). The Cr4+ emission band was observed with its peak at 1.35 mum and measured to be about 6% with respect to Yb3+ IR luminescence (lambda = 1.03 mum). Analysis of the crystal absorption and luminescence spectra allows one to conclude that Yb3+-Cr4+ energy transfer is a mechanism responsible for the B-3(2)(T-3(2))-B-3(1)((3)A(2)) emission of Cr4+ ions. This crystal is promising as an efficient source of the near infrared emission. (C) 2004 Elsevier B.V. All rights reserved.

Infrared (1.2-1.6 mu m) luminescence in Cr4+: Yb3Al5O12 single crystal with 940 nm diode pumping

Infrared (1.2-1.6 mu m) luminescence in a ytterbium aluminium garnet (YbAG) crystal, doped with Cr (0.05 at.%) ions, was investigated under CW laser diode pumping (lambda = 940 nm). The Cr4+ emission band was observed with its peak at 1.34 mu m and measured to be about 1.3 times with respect to Yb3+ IR luminescence (lambda = 1.03 mu m). We demonstrate that for the excitation wavelength of 940 nm Yb3+ ions act as sensitizers of the B-3(2)(T-3(2))-B-3(1)((3)A(2)) emission of Cr4+ ions. This crystal is promising as a high-efficient system for tunable laser (1.2-1.6 mu m) output. (c) 2004 Elsevier B.V. All rights reserved.

果糖1,6-二磷酸酯酶的代谢调控

<正> 果糖1,6-二磷酸酯酶(FBPase 1)在生物体内糖异生代谢途径中起着重要的作用。当二价金属离子存在时,它催化果糖1,6-二磷酸(Fru-1,6-P_2)水解生成果糖6-磷酸(Fru-6-P)和无机磷。它是一个由4个相同亚单位构成的蛋白质,其亚单位分子量约为35 000～40 000。FBPase 1可被蛋白水解酶降解修饰,使其最适pH从7.5变为9.2。该酶受AMP及果糖2,6-二磷酸(Fru-2,6-P_2)

Metamorphic InGaAs quantum wells for light emission at 1.3-1.6 mu m

Metamorphic InGaAs quantum well structures grown on GaAs reveal strong light emission at 1.3-1.6 mu m, smooth surface with an average roughness below 2 nm. and good rectifying I-V characteristics. Dark line defects are found in the QW Post growth thermal annealing further improves the luminescence efficiency but does not remove those dark line defects. Some challenges of epitaxial growth using this method for laser applications are discussed. (c) 2006 Elsevier B.V. All rights reserved.