bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Resolution and Kinetics of Electron Self-Exchange of High-Spin Manganese(II)/(III) Cage Complexes
Authors: Anderson PA , Creaser II , Dean C , Harrowfield JM , Horn E , Martin LL , Sargeson AM , Snow MR , Tiekink ERT
Published: September 2010

The ligand sarcophagine ( sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane ) rapidly reacts with [ Mn (OH2)6]2+ to form the nearly colourless [ Mn ( sar )]2+ ion, which can readily be oxidized to the bright orange [Mn ( sar )]3+ ion (E°′+0.53 V v. n.h.e. in 0.1 mol l-1 CF3SO3H at 295 K). A single-crystal structure determination on [ Mn ( sar )](NO3)3, space group I 42d, a 15.549(6), c 19.014(6) Ǻ, R 0.051, Rw 0.049 for 608 'observed' reflections, shows the coordination geometry of the manganese(III) ion, with site symmetry 2, to be subject to a Jahn-Teller distortion, giving three pairs of Mn -N bond lengths of 2.18(1), 2.13(1) and 2.08(1)Ǻ. The [ Mn ( sar )]3+ ion is stable in strongly acidic aqueous solutions, but in solutions of pH > 3 undergoes deprotonation and subsequent disproportionation reactions. The manganese(II) complex ion is less stable in acidic solutions, undergoing hydrolysis at a rate showing a first-order dependence on both proton and chloride ion concentrations. Both [ Mn ( sar )]2+ and [ Mn ( sar )]3+ can be obtained in chiral forms, and the rate constant for electron self-exchange obtained by polarimetric measurements on solutions of mixtures of [ Mn ( sar )]2+ and [ Mn ( sar )]3+ of opposite chirality is 30 dm3 mol-1s-1 at 298 K, I = 0.1 M.
Studies of Australian Ascidians. II. Novel Cytotoxic Iodotyrosine-Based Alkaloids From Colonial Ascidians, Aplidium sp
Authors: Carroll AR , Bowden BF , Coll JC
Published: September 2010

Samples of colonial ascidians, Aplidium sp., have yielded three novel iodinated L-tyrosine alkaloids (1)-(3). The structures of these compounds were delineated on the basis of one and two-dimensional n.m.r. experiments at 300 MHz, and confirmed by the total synthesis of one of them (2).
A Single-Beam Approach to the Absorption Spectroscopy of Microcrystals
Authors: Krausz E
Published: September 2010

A single-beam microcrystal absorption spectrometer system is described that operates in the range 300-2600 nm, on crystals smaller than 50 μm , in the temperature range 5-300 K, with resolution better than 1 cm-1. The computer control of data acquisition and baseline storage with interpolation generates data of exceptional quality, and simplifies operation. The salient features of the apparatus are discussed, and the optimal sample absorption is calculated. Examples of optical spectra with relevance to some current interests in inorganic chemistry are provided.
Reaction of Benzo[f][1,7]naphthyridin-7-amine With Aromatic Aldehydes
Authors: Paluszewski M , Sliwa W
Published: September 2010

The reaction of benzo [f][1,7]naphthyridin-7-amine with aromatic aldehydes ArCHO [ Ar = Ph, 3-Y(C6H4), where Y = Me, No2, Cl ] was investigated. Instead of the expected formation of azomethines the cyclization leading to benzimidazonaphthyridines was observed.
Boron Trifluoride Catalyzed Rearrangements of Novel Epoxide Derivatives of Manool and Manoyl Oxide
Authors: Grant PK , Lynch GP , Simpson J , Wong G
Published: September 2010

The preparation of four epoxides (1)-(4) derived from manool [labda-8(17),14-dien-13-ol] and manoyl oxide (8,13-epoxylabdane) via diosphenols is reported. Lewis acid promoted intramolecular rearrangements of these were investigated. Reaction of epoxide (1) with boron trifluoride etherate resulted in the isolation of a novel dimer (44), the structure being elucidated by X-ray crystallography. However, epoxides (2)-(4) yielded monomeric rearrangement products.
The Chemistry of Laurenene. XV. Preparation of 15βH-Lauren-1-ene and Deuterium-Labeled Laurenan-2β-ol
Authors: Clarke DB , Weavers RT
Published: September 2010

A synthesis of laurenan-2β-ol labelled with deuterium at various positions has been undertaken to infer various points about a rearrangement mechanism. During this work, syntheses of the 15-epimer of lauren-1-ene and some derivatives were also developed.
Peptides From Australian Frogs. The Structures of the Dynastins From Limnodynastes salmini and Fletcherin From Limnodynastes fletcheri
Authors: Bradford AM , Raftery MJ , Bowie JH , Wallace JC , Tyler MJ
Published: September 2010

The dermal glandular extracts of the Australian frog Limnodynastes salmini contain a number of peptides of the dynastin family. The related species Limnodynastes fletcheri contains only one peptide in its glandular extract; this compound, which we have named fletcherin, is unusual amongst amphibian peptides in that the N-terminal group corresponds to Ala. The primary structures of the dynastins and fletcherin are described.
Structural and Electronic Properties of Iron(II) and Nickel(II) Complexes of 2,6-Bis(triazol-3-yl)pyridines
Authors: Sugiyarto KH , Craig DC , Rae AD , Goodwin HA
Published: September 2010

Iron(II) and nickel(II) bis ( ligand ) complexes of 2,6-bis(1,2,4-triazol-3-yl)pyridine and the substituted derivatives 2,6-bis(1(N)-methyl-1,2,4-triazol-3-yl)pyridine 2,6-bis(5-methyl-1,2,4-triazol-3-yl)pyridine and 2,6-bis(1,5-dimethyl-1,2,4-triazol-3-yl)pyridine have been prepared. Coordination of the unsubstituted ligand through N4 of the triazolyl moieties is confirmed by structure determination of [FeL2][NO3]2.4H2O and [NiL2]Cl2.3H2O. In both of these complex salts there is an extensive hydrogen-bonded network involving the N 1-H group, the anions and the water molecules. Bis [2,6-bis(1,2,4-triazol-3-yl)pyridine]nickel(II)
dichloride trihydrate : monoclinic, space group C2/c, a 17.971(5), b 11.433(1), c 14.849(5) Ǻ, β 122.20(1)°, Z 4. Bis [2,6-bis(1,2,4-triazol-3-yl)pyridine]iron(II) dinitrate tetrahydrate : tetragonal, space group 141/a, a 11.488(2), c 21.055(7) Ǻ, Z 4. [FeL2]Cl2.3H2O is isostructural with the nickel complex and is high-spin but undergoes a partial transition to low-spin at low temperature. Conversion to low-spin is complete when the complex is dehydrated, and this change is associated with the effects of the hydrogen bonding. The solid iron complexes of the N-methyl-substituted ligands in which the hydrogen-bonding potential is reduced are entirely high-spin down to 77K. The complex of the 5-methyl derivative undergoes a continuous singlet ↔ quintet transition below room temperature.
Two New Scalarane Sesterterpenes: Isoscalarafuran-A and -B, Epimeric Alcohols From a Southern Australian Marine Sponge, Spongia hispida
Authors: Davis R , Capon RJ
Published: September 2010

A specimen of the marine sponge Spongia hispida ( Lamarck , 1814), collected in the Great Australian Bight, has yielded the known marine sesterterpene hyrtiosal (1), together with two new scalarane sesterterpenes, isoscalarafuran-A (2) and isoscalarafuran -B (3). The structures for these two new metabolites were secured by detailed spectroscopic analysis, comparison with model compounds, and molecular modelling.
Synthesis and Structure of Diacetato-[1-benzyloxy-1,1-bis(N-methylimdazol-2-yl)ethane]zinc(II)
Authors: Boyd SE , Harding MM , Buys IE , Hambley TW
Published: September 2010

The synthesis and single-crystal X-ray structure determination of the title compound are described. The crystals are monoclinic, P21/c, a 10.064(2), b 13.096(2), c 17.722(3) Ǻ, β 104.68(2)°; the structure was refined to a residual of 0.033 for 3138 independent observed reflections. The coordination about zinc is intermediate between four- and five-coordinate, and the angle between the planar imidazole groups is 14.9°.
A Non-Linear Correlation Model for the Relative Permittivity of Ternary Amphiprotic (Solvent) Mixtures
Authors: Corradini F , Marcheselli L , Marchetti A , Tagliazucchi M , Tassi L , Tosi G
Published: September 2010

Relative permittivities (є) were determined for ternary ethane-1,2-diol (component 1)/2- methoxyethanol (component 2)/water (component 3) mixtures at five temperatures ranging from 5 to 25°C and over the mole fraction composition range 0 ≤ Xi ≤ 1. The data have been fitted to a model equation that could be useful for predictive є calculations. From the measured є values, the excess relative permittivity єE has been evaluated in order to test for three-component adducts. The values of єE have been found to be negative for all the ternary mixtures under all the experimental conditions, which suggests a strong interaction network through hydrogen bonding, although evidence for a discrete three-component adduct was not forthcoming.
Nitration of 4-Chloro-2,3,6-trimethylphenol, 3-Chloro-2,4,6-trimethylphenol and 2,3,4,6-Tetramethylphenol; 15N-Labeling Studies in the Reaction of 2,3,4,6-Tetramethyl-4-nitrocyclohexa-2,5-dienone With Nitrogen Dioxide
Authors: Calvert JL , Hartshorn MP , Robinson WT , Wright GJ
Published: September 2010

The effects of C3 and C4 substituents (Cl, Me) on the reactions of 2,6-dimethylphenols (10)-(12) with nitrogen dioxide in benzene have been examined. In the course of this work X-ray crystal analyses are reported for 14 compounds (13)-(16), (19), (21), (32), (34), (36) and (38)-(42). A 15N-labelling study of the reaction of 2,3,4,6-tetramethyl-4-nitrocyclohexa-2,5-dienone (37) with nitrogen dioxide in benzene is reported.
Grignard Addition Reactions to 1,4-Difunctionalized But-2-ynes
Authors: Desilva AN , Francis CL , Ward AD
Published: September 2010

Trisubstituted alkenes of E geometry have been prepared by anti addition of Grignard reagents to 1,4-difunctionalized but-2-ynes. Addition of primary, secondary and aromatic Grignard reagents to but-2-yne-1,4-diol provided (E)-2-substituted but-2-ene-1,4-diols as major products along with the corresponding 2-substituted buta-2,3-dien-1-ols. Addition of phenylmagnesium bromide to the mono- and di-methyl ethers of but-2-yne-1,4-diol gave 2,3-diphenyl-1,3-diene. Treatment of 4-dimethylaminobut-2-yn-1-ol with primary alkyl and alkenyl Grignard reagents afforded the 2-substituted anti addition product regiospecifically, stereospecifically and in high yield. Reaction of 1-dimethylamino-4-methoxybut-2-yne with butylmagnesium bromide provided only the 3-substituted anti addition product in good yield.
Synthesis and Single Crystal Structure Determination of Bis(carbido)bis(μ-diphenylphosphido)heptadecacarbonyloctaruthenium-Dichloromethane (1/1), Ru8(μ6-C)(μ5-C)(μ-PPh2)2(CO)17.CH2Cl2
Authors: Adams CJ , Bruce MI , Skelton BW , White AH
Published: September 2010

The synthesis and room-temperature single-crystal X-ray structure determination of the title compound are recorded. Crystals are monoclinic, P 21/c, a 14.43(2), b 18.39(1), c 23.64(3) Ǻ, β 123.16(7)°, Z = 4, isostructural with the recently described Fe3Ru5 analogue; R was 0.048 for 6892 'observed' data [I > 3σ(I)]. The cluster is one of the few containing separated carbide ligands within a polyhedral metal skeleton, consisting of an Ru5C square pyramid and an Ru6C octahedron sharing a triangular face, with two PPh2 groups bridging opposite Ru-Ru vectors in each polyhedron.
Chemistry Around δ-Terpineol
Authors: Bull SD , Carman RM
Published: September 2010

Bromination, hydroboration, epoxidation, 1,2-dihydroxylation and acidification reactions upon δ-terpineol are described.
Crystal Structure of a Bis(2,2'-bipyridine)ruthenium(II) Complex of a Dimethoxynaphthalene-Norbornyl-Pyridazine Ligand
Authors: Golka A , Craig DC , Paddonrow MN
Published: September 2010

The bis (2,2′-bipyridine)(6,11-dimethoxy-1,4-di(2′-pyridyl)-5,12-dihydro-5,12-methanonaphtho-[2,3-g] phthalazine )ruthenium(II) complex exists in two diastereomeric forms, (3a) and (3b). In order to make an unambiguous assignment of the configuration of each stereoisomer, a single-crystal X-ray structure of the hexafluorophosphate salt of the less soluble isomer (in methanol/acetone) was carried out. It was found that the structure of this material corresponded to (3a). Differences in he 1H n.m.r. spectra of (3a) and (3b) are discussed in light of their structures.
Structural Characterization of a Cage Ligand Fragmentation Reaction
Authors: Harrowfield JM , Sargeson AM , Skelton BW , White AH
Published: September 2010

The room temperature X-ray single-crystal structural characterization of a protonated copper(II) complex of a ligand artefact, L′, of L = N-Me6sar (described in an accompanying paper) is recorded, the new ligand L′ being generated formally by elimination of a CH2CH2 bridge between a pair of nitrogen donor atoms of L. The complex, [ ClCu (H2L′) (ClO4)3.2H2O, is orthorhombic, Pccn , a 22.528(7), b 10.544(3), c 13.748(6) Ǻ, Z = 4 formula units, R being 0.053 for 1133 independent 'observed' [I > 3σ(I)] reflections. The cation, containing five-coordinate square-pyramidal ClCuN4 copper, is disposed with the Cu- Cl bond [2.458(3)Ǻ] lying on a crystallographic 2 axis; Cu-N distances are 2.094(8) and 2.093(8)Ǻ.
Binding of Nitrogen Heterocyclic Ligands and Tetraphenyl-Substituted Ions by β-Cyclodextrins
Authors: Johnson MD , Mcintosh CA , Reinsborough VC
Published: September 2010

Binding constants obtained spectrofluorometrically are reported for β- cyclodextrin (substituted and unsubstituted ) inclusion of several commonly used nitrogen heterocyclic ligands and tetraphenyl-substituted ions.
The Mechanism and Stereochemistry of Chlorination of 2,4-Dichloro-3,,5,6-trimethylphenol and 2,4-Dichloro-3,6-dimethylphenol
Authors: Gordon JLM , Hartshorn MP , Martyn RJ , Robinson WT , Wright GJ
Published: September 2010

Electrophilic attack of chlorine on 2,4,6-trichloro-3,5,6-trimethylcyclohexa-2,4-dienone (2a) gives the trans-pentachloro ketones (3a) and (4a), while similar reaction of 2,4,6-trichloro-3,6-dimethylcyclohexa-2,4-dienone (2b) gives the trans- pentachloro ketones (3b) and (4b), resulting from 2,5- and 4,5-addition of chlorine. The probable stereochemistry of chlorine addition in ketones (3b) and (4b) is determined by chlorination of 2,4-dibromo-3,6-dimethylphenol (6). X-Ray crystal structures are reported for compounds (3a,b), (7) and (8).
Structural Systematics of Rare Earth Complexes. VI. The Higher Hydrates of the Rare Earth Trichlorides
Authors: Kepert CJ , Skelton BW , White AH
Published: September 2010

Single-crystal room-temperature X-ray structure determinations of improved precision are reported for certain higher hydrates of the rare earth trichlorides (LnCl3.7H2O, Ln = La, Pr; LnCl3.6H2O, Ln = Nd, Lu) (triclinic, Pī, and monoclinic, P 2/n, forms respectively) in order to define hydrogen-bonding arrays within the two lattices.
Structural Characterization of a Hydrated 1:1 Scandium(III) Picrate-Picric Acid Adduct
Authors: Harrowfield JM , Skelton BW , White AH
Published: September 2010

Hydrated scandium(III) picrate has been crystallized in association with excess picric acid to give a 1:1 adduct as material sufficiently substantial to allow single-crystal X-ray structural characterization at c. 295 K. [Sc( pic )2(OH2)4]( pic )( Hpic ).~8.2H2O is monoclinic, P 21/c, a 16.304(9), b 20.061(6), c 14.587(9) Ǻ, β 112.98(5)°, Z = 4; R was 0.078 for 2632 reflections [I > 3σ(I)]. The scandium is six-coordinate, the coordination sphere comprising a trans pair of phenolic picrate oxygen atoms [Sc-O, 2.019(8), 2.046(8) Ǻ; Sc-O-C, 147.6(9), 147.7(9)°] and four water molecule oxygens at appreciably longer distances [Sc-O, 2.100(9)-2.121(8)Ǻ].
The Synthesis of Some Lipophilic Tetradentate Ligands for Use in the Formation of Metal-Linked Polymers
Authors: Crossley MJ , Gorjian S , Sternhell S , Tansey KM
Published: September 2010

Two lipophilic tetradentate ligands, 5,5′-di-t-butyl- and 5,5′-dihexyl-2,2′-bipyrimidine, were prepared via either Ullmann or nickel(0)-promoted reactions in low but useful yields. Approaches towards the synthesis of lipophilic ligands based on 2,2′-biimidazole, namely 4,4′,5,5′-tetrabutyl-2,2′-biimidazole (from decane-4,5-dione) and various 4,4′,5,5′-tetra( arylamino )- 2,2′-biimidazoles (from 4,4′,5,5′-tetrabromo-2,2′-biimidazole and arylamines), and a 2,2′- bibenzimidazole , 5,5′,6,6?-tetra( octyloxy )-2,2′-bibenzimidazole (from N,N′- bis [4,5-di( octyloxy )-2-nitrophenyl] oxamide ), were uniformly unsuccessful for preparing the 2,2′-biheteroaryl compounds.
Quinquedentate Coordination of 3-[(2'-Amino-ethyl)amino]-2-[(2″-aminoethyl)aminomethyl]propionic Acid (LH). Crystal Structure of trans-[Co(L)Cl][ClO4].H2O And Molecular Mechanics Examination of Isomers
Authors: Bernhardt PV , Hambley TW , Lawrance GA , Molloy KJ
Published: September 2010

The anion (1c) of the branched polyamino acid 3-[(2′-aminoethyl)amino]-2-[(2″-aminoethyl)- aminomethyl ] propionic acid (1b) binds as a quinquedentate ligand to cobalt(III). Reaction with cobalt(II) chloride, followed by oxidation and acidification, yields exclusively one isomer of [Co(1c) Cl ]+. The complex was crystallized readily as a perchlorate monohydrate salt, in the monoclinic space group P 21/n, a 7.921(2), b 17.357(4), c 11.852(4) Ǻ, β 107.25(2)°, Z = 4; a single-crystal X-ray structure determination was refined to R 0.033 for 2099 `observed' reflections. The carboxylate and two adjacent secondary amines occupy an octahedral face, with the chloro ligand trans to the carboxylate , and the secondary amines adopt R,S stereochemistries. The Co-O distance [1.901(2) Ǻ] is at the short end of the range of cobalt- carboxylate bonds, and Co-N distances [average 1.944 Ǻ (primary amines), average 1.950 Ǻ (secondary amines)] are slightly shorter than average for Co-N bonds. The Co- Cl distance is 2.255(1) Ǻ. Molecular mechanics examination of all possible isomers and conformers of [Co(1c) Cl ]+ and of the related pentaamine
1,5,9-triamino-5-methyl-3,7-diazanonane (2) indicate a greater variation in
strain energy across the range of isomers and conformers in the latter more
strained system.
Structural Studies of Aromadendrane-1,2-diols
Authors: Ghisalberti EL , Patalinghug WC , Skelton BW , White AH
Published: September 2010

The structures of two aromadendranediols derived from the naturally occurring sesquiterpenes (+)-ledene and (+)-spathulenol have been determined by X-ray crystallographic methods.
Synthesis of (±)-8-Oxotetrahydropalmatine and (±)-Gusanlung B
Authors: Nimgirawath S , Ponghusabun O
Published: September 2010

The 8-oxotetrahydroprotoberberine alkaloids (�)-8-oxotetrahydropalmatine and (�)- gusanlung B have been synthesized by radical-initiated 1,6-cyclization of the corresponding 2-arylcarbonyl-1-methylenetetrahydroisoquinolines.
The Preparation of Pyrrole-2-carboxylates From Vinyl Sulfones
Authors: Arnold DP , Burgessdean L , Hubbard J , Rahman MA
Published: September 2010

The reaction of the anion of ethyl isocyanoacetate with suitably substituted vinyl p- tolyl sulfones gives fair to good yields of pyrrole-2-carboxylates substituted in the 3-, 4- or 3- and 4-positions. From the reaction of 1-phenyl-1-tolylsulfonylethene with ethyl isocyanoacetate , two diastereoisomers of ethyl 4,6-diphenyl-4,6-bis(p- tolylsulfonyl )-3,4,5,6-tetrahydro-2H-azepine-2-carboxylate (4) were also isolated.
Structural Study of Dehydrocurvularin, an Inhibitor of Microtubule Assembly
Authors: Almassi F , Ghisalberti EL , Skelton BW , White AH
Published: September 2010

The solid-state structure of the fungal metabolite E-dehydrocurvularin (2), an inhibitor of microtubule assembly, has been determined by a single-crystal room-temperature X-ray study for comparison with curvularin (1). Crystals of (2) are orthorhombic, P212121, a 17.757(9), b 10.031(6), c 8.069(4) Ǻ, Z = 4; R was 0.060 for 988 independent 'observed' [I > 3σ(I)] diffractometer reflections. The results of this study show that (1) and (2) adopt opposite helicity in the solid state.
Regioselective 2,3-Di-O-silylation of Methyl 6-Chloro-6-deoxy-α-D-glucopyranoside
Authors: Collins DJ , Jones ED
Published: September 2010

Reaction of methyl 6-chloro-6-deoxy-α-D-glucopyranoside (1) with an excess of t- butyldimethyl-silyl chloride in dimethylformamide in the presence of imidazole gave 53% of the corresponding 2,3-di-O-t-butyldimethylsilyl ether (2); under similar conditions D-gluconic acid 1,5-lactone (3) afforded 83% of the 2,3,4,6-tetra-O-t-butyldimethylsilyl ether (4).
Photochemically Induced C-H Bond Activation and Ligand Transfer in the Reaction of [Cp2Rh2(CO)(CF3C2CF3)] With [(Cp′) Mn (CO)2( thf )]: Structural Characterization of the Rh4 Product
Authors: Dickson RS , Liddell MJ , Skelton BW , White AH
Published: September 2010

A room-temperature single-crystal X-ray diffraction study carried out on a product of a sunlight induced reaction between [Cp2Rh2(CO)(CF3C2CF3)] and [(Cp′) Mn (CO)2( thf )] in 2:1 ratio in hydrocarbon solution establishes it to be tetranuclear [(Cp4Rh4)(CF3C=CHCF3)2(CH3-C5H3)]; crystals of the latter are triclinic, Pī , a 15.803(9), b 13.445(8), c 8.966(6) Ǻ, α 75.92(5), β 80.68(5), γ 65.46(4)°, Z = 2. Full-matrix refinement for 3431 'observed' [I > 3σ(I)], absorption-corrected data converged at R 0.056. The structure comprises a pair of enantiomeric [(Cp2Rh2)(CF3C=CHCF3 binuclear units unsymmetrically linked by the central CH3C5H3 ring, by way of the η1,η2-C=CH and η1,η2-C= CMe functionalities.
Lamellarins O and P: New Aromatic Metabolites From the Australian Marine Sponge Dendrilla cactos
Authors: Urban S , Butler MS , Capon RJ
Published: September 2010

A specimen of Dendrilla cactos collected during trawling operations in Bass Strait, Australia, has yielded two new alkaloids, lamellarin-O (17) and lamellarin-P (18). Both these metabolites are examples of the lamellarin structure class, previously reported from tunicates and a mollusc; however, in these examples the pyrrole ring system is not fused to adjacent aromatic rings. The structures of (17) and (18) were secured by spectroscopic analysis and partial synthesis.
Synthesis of Conjugated Trienes and Related Oxidation Products of α-Farnesene
Authors: Brimble MA , Rowan DD , Spicer JA
Published: September 2010

The synthesis of conjugated trienes and related oxidation products of α- farnesene (1), principally from the epoxides of α- farnesene (1), is reported. Base-promoted ring opening of 6,7-epoxide (4) by KOBut/LiNPri2 affords the conjugated triene (2), whilst the 3,4-epoxide (5) affords trienol (7). In contrast, 10,11-epoxide (6) fails to undergo epoxide ring opening; it rearranges to the conjugated triene epoxide (8). Base-promoted ring opening of bisepoxide (9) afforded trienol epoxide (11) at -30°C, whilst cyclization to tetrahydrofurans (10a,b) occurred at room temperature. Photosensitized oxidation of 10,11-epoxide (6) followed by in situ treatment with acid gave the cyclic peroxide (3) and on reduction triol (12). Bisallylic alcohol (13) was prepared by alkylation of 3-methylsulfolene with geranial. Trienes (2) and (3) have been isolated previously as autoxidation products of α- farnesene (1) and are implicated as the causal agents of superficial scald of stored apples.
Experiments Directed Towards the Synthesis of Anthracyclinones. XXIII. A Synthesis of Fridamycin E
Authors: Pausler MG , Rutledge PS
Published: September 2010

Fridamycin E (1) has been synthesized in six steps from the anthrarufin mono(chloroallyl) ether (10). The synthesis was based on a titanium-mediated aldol-like addition of a (-)- menthyl acetate enolate to the ketone (9). Similar additions to the aldehydes (23) and (25) are reported.
Nucleophilic Catalysis by HPO42- in the Hydrolysis of Cr2O72-. Formation and Decay of HO3POCrO32-
Authors: Brasch NE , Buckingham DA , Clark CR
Published: September 2010

The initial reaction of Cr2O72- in phosphate buffer (pH 6.03-8.54, 25.0°C, I = 1.0 M NaClO4) follows the rate law kobs = kK [HPO42]/(1+K[HPO42-]). This is interpreted as arising from the reversible and rapid formation of a chromium(VI)- phosphato intermediate of increased coordination number (K = 5.5�1.3M-1), and rate-determining loss of CrO42- from this species (k = 4.4�0.5 s-1) to give HO3POCrO32- ( pKc a= 6.96). This appears to be the first clear demonstration of an addition-elimination (stepwise) mechanism for substitution at chromium (VI). Subsequent equilibration of HO3POCrO32- to give HCrO4- and H2PO4- (K = 5.95�1.90 M-1) is seen as a separate process which is subject to specific H+ and OH-, and general base (HPO42-) catalysis, in addition to a spontaneous reaction.
Distribution of resting and ligand-bound ErbB1 and ErbB2 receptor tyrosine kinases in living cells using number and brightness analysis
Authors: Nagy Peter , Claus Jeroen , Jovin Thomas M. , Arndt-Jovin Donna J.
Published: September 2010

Ligand-driven dimerizations of ErbB receptor subunits fulfill a fundamental role in their activation. We have used the number and brightness analysis technique to investigate the existence of preformed ligand-independent dimers and clusters and to characterize the initial steps in the activation of ErbB1 and ErbB2. In cells expressing 50,000–200,000 receptors, ErbB1 was monomeric in the absence of ligand stimulation, whereas in CHO cells with receptor levels > 500,000 as much as 30% of ErbB1 was present as preformed dimers. EGF induced the formation of ErbB1 dimers as well as larger clusters (up to pentamers) that colocalized with clathrin-coated pits. The distribution of unstimulated ErbB2 in cells expressing 3·10
5
 - 10
6
receptors was fundamentally different, in that this receptor was present in preformed homoassociated aggregates containing 5–10 molecules. These constitutive ErbB2 homoclusters colocalized with caveolae, increased in size at subphysiological temperatures, but decreased in size upon EGF stimulation. We conclude that these ErbB2 clusters are promoted primarily by membrane-mediated interactions and are dispersed upon ligand stimulation.
Proteomic analyses identify a diverse array of nuclear processes affected by small ubiquitin-like modifier conjugation in
Arabidopsis
Authors: Miller Marcus J. , Barrett-Wilt Gregory A. , Hua Zhihua , Vierstra Richard D.
Published: September 2010

The covalent attachment of SUMO (small ubiquitin-like modifier) to other intracellular proteins affects a broad range of nuclear processes in yeast and animals, including chromatin maintenance, transcription, and transport across the nuclear envelope, as well as protects proteins from ubiquitin addition. Substantial increases in SUMOylated proteins upon various stresses have also implicated this modification in the general stress response. To help understand the role(s) of SUMOylation in plants, we developed a stringent method to isolate SUMO-protein conjugates from
Arabidopsis thaliana
that exploits a tagged SUMO1 variant that faithfully replaces the wild-type protein. Following purification under denaturing conditions, SUMOylated proteins were identified by tandem mass spectrometry from both nonstressed plants and those exposed to heat and oxidative stress. The list of targets is enriched for factors that direct SUMOylation and for nuclear proteins involved in chromatin remodeling/repair, transcription, RNA metabolism, and protein trafficking. Targets of particular interest include histone H2B, components in the LEUNIG/TOPLESS corepressor complexes, and proteins that control histone acetylation and DNA methylation, which affect genome-wide transcription. SUMO attachment site(s) were identified in a subset of targets, including SUMO1 itself to confirm the assembly of poly-SUMO chains. SUMO1 also becomes conjugated with ubiquitin during heat stress, thus connecting these two posttranslational modifications in plants. Taken together, we propose that SUMOylation represents a rapid and global mechanism for reversibly manipulating plant chromosomal functions, especially during environmental stress.
Parenting Factors Associated with Reduced Adolescent Alcohol Use: A Systematic Review of Longitudinal Studies
Authors: Ryan Siobhan M. , Jorm Anthony F. , Lubman Dan I.
Published: September 2010

Objective: To identify parenting strategies associated with adolescent alcohol consumption that parents can use to implement new national guidelines regarding alcohol consumption by people under the age of 18.

Methods: A systematic search of academic literature employing the PRISMA method identified 77 relevant articles. Inclusion criteria for the review were (i) longitudinal cohort studies; (ii) measurement of one or more parenting factors during adolescence or pre-adolescence (between the ages of 8 and 17) as a predictor (iii) outcome measurement of any alcohol use and/or alcohol related problems during adolescence at least one time point after the initial parenting factor was measured, and/or problem drinking in adulthood. Studies were excluded if alcohol use was combined with other substance use or problem behaviour as an outcome variable, or if different parenting factors were combined as a single predictor variable for analysis. Stouffer's method of combining p values was used to determine whether associations between variables were reliable.

Results: Twelve parenting variables were investigated in these studies: parental modelling, provision of alcohol, alcohol-specific communication, disapproval of adolescent drinking, general discipline, rules about alcohol, parental monitoring, parent–child relationship quality, family conflict, parental support, parental involvement, and general communication. We found that delayed alcohol initiation was predicted by: parental modelling, limiting availability of alcohol to the child, parental monitoring, parent–child relationship quality, parental involvement and general communication. Reduced levels of later drinking by adolescents were predicted by: parental modelling, limiting availability of alcohol to the child, disapproval of adolescent drinking, general discipline, parental monitoring, parent–child relationship quality, parental support and general communication.

Conclusions: A number of parenting strategies were identified that parents can use to reduce their adolescent's alcohol consumption. These could be promoted to parents to help them implement new national guidelines on alcohol use.
Realistic calculations of carbon-based disordered systems
Authors: Rocha A R , Rossi Mariana , Silva Antônio J R da , Fazzio A
Published: September 2010

Carbon nanotubes rank amongst potential candidates for a new family of nanoscopic devices, in particular for sensing applications. At the same time that defects in carbon nanotubes act as binding sites for foreign species, our current level of control over the fabrication process does not allow one to specifically choose where these binding sites will actually be positioned. In this work we present a theoretical framework for accurately calculating the electronic and transport properties of long disordered carbon nanotubes containing a large number of binding sites randomly distributed along a sample. This method combines the accuracy and functionality of ab initio density functional theory to determine the electronic structure with a recursive Green's functions method. We apply this methodology on the problem of nitrogen-rich carbon nanotubes, first considering different types of defects and then demonstrating how our simulations can help in the field of sensor design by allowing one to compute the transport properties of realistic nanotube devices containing a large number of randomly distributed binding sites.
Multilayer epitaxial graphene grown on the
surface; structure and electronic properties
Authors: Sprinkle M , Hicks J , Tejeda A , Taleb-Ibrahimi A , Le Fèvre P , Bertran F , Tinkey H , Clark M C , Soukiassian P , Martinotti D , Hass J , Conrad E H
Published: September 2010

We review the progress towards developing epitaxial graphene as a material for carbon electronics. In particular, we discuss improvements in epitaxial graphene growth, interface control and the understanding of multilayer epitaxial graphene's (MEG's) electronic properties. Although graphene grown on both polar faces of SiC will be discussed, our discussions will focus on graphene grown on the
C-face of SiC. The unique properties of C-face MEG have become apparent. These films behave electronically like a stack of nearly independent graphene sheets rather than a thin Bernal stacked graphite sample. The origins of multilayer graphene's electronic behaviour are its unique highly ordered stacking of non-Bernal rotated graphene planes. While these rotations do not significantly affect the inter-layer interactions, they do break the stacking symmetry of graphite. It is this broken symmetry that leads to each sheet behaving like isolated graphene planes.
Retracted: Modeling fracture toughness of functionally graded steels in crack divider configuration
Authors: Mohandesi J Aghazadeh , Nazari A , Vishkasogheh Mehdi Hamid , Abedi Mohammad
Published: September 2010

Fracture toughness of functionally graded steels in crack divider configuration has been modeled. By utilizing plain carbon and austenitic stainless steel slices with various thicknesses and arrangements as electroslag remelting electrodes, functionally graded steels were produced. The fracture toughness of the functionally graded steels was found to depend on the type, volume fraction and position of the phases present. According to the area under the stress-strain curve of each layer in the functionally graded composites, a mathematical model has been presented for fracture toughness prediction using the rule of mixtures. In addition, the fracture toughness of the composites has been simulated by the 3D dynamic finite element method. There is good agreement between experimental results and those acquired from the numerical and mathematical models.
Faecal Calprotectin in Term and Preterm Neonates
Authors: Kapel Nathalie , Campeotto Florence , Kalach Nicolas , Baldassare Mariella , Butel Marie‐José , Dupont Christophe
Published: September 2010

Objectives:

The aim of this review was to examine the characteristics of the faecal calprotectin assay in neonates and the evidence for its use as a noninvasive marker of intestinal illnesses during the neonatal period.

Methods:

Bibliographic searches were performed in the MEDLINE electronic database up to February 2010 looking for the following words (all fields): “infants” or “neonates” and “calprotectin.” Twenty studies, in which 1180 neonates were enrolled, were selected.

Results:

During the neonatal period, calprotectin levels are characterized by significantly higher values in both healthy full‐term and preterm infants during their first year of life compared with reference values established for children and adults. No difference was observed according to gestational age or birth weight, whereas a higher faecal calprotectin level was detected during intestinal distress in neonates with either inflammatory or patent digestive alterations. Despite high interindividual variations, cutoff levels are proposed to identify infants with a high risk of intestinal illnesses.

Conclusions:

Compared with adults and children, healthy full‐term and preterm neonates have high calprotectin levels. The measurement of calprotectin levels in faeces can be a promising noninvasive clinical screening test for intestinal distress in neonates.
Regulatory T Cells and T Helper Subsets in Breast‐fed Infants With Hematochezia Caused by Allergic Colitis
Authors: Cseh Áron , Molnár Kriszta , Pintér Petra , Szalay Balazs , Szebeni Beata , Treszl Andras , Arató Andras , Vásárhelyi Barna , Veres Gabor
Published: September 2010

The objective of our study was to investigate the prevalence of CD4+ T lymphocyte subsets and their commitment to TH1 or TH2 direction in 10 infants with allergic colitis (AC) and 10 healthy controls. Infants with AC presented with a higher ratio of naïve to memory cells, lower prevalence of activated CD4+CD25+ cells and FoxP3+ regulatory cells, and a shift to TH2 direction in balance compared with controls. These alterations are normalized upon cessation of AC symptoms on elemental L‐amino acid formula. These findings suggest the importance of antigen exposure in AC in infancy.
Performing Kasai Portoenterostomy Beyond 60 Days of Life Is Not Necessarily Associated With a Worse Outcome
Authors: Wong KKY , Chung PHY , Chan IHY , Lan LCL , Tam PKH
Published: September 2010

The introduction of Kasai portoenterostomy has dramatically improved the management and survival of children with biliary atresia. The success rate of this operation worldwide varies with different centers. In this respect, many authors have studied the correlation of a successful outcome with various factors, such as the experience and workload of the surgical center, the use of postoperative steroids, the underlying biliary anatomy, as well as the age of patients at the time of the operation. Indeed, the age of 60 days has been used by clinicians as a critical time beyond which the rate of success of the Kasai operation markedly reduces. Despite this worldwide adoption, clear evidence supporting this critical operative time is still lacking. We undertook a review of our experience in the management of children with biliary atresia and focused specifically on the issue of the timing of operation. We showed that performing the Kasai operation beyond the age of 60 days was not associated with a worse outcome and that a high percentage of patients could still achieve good bile flow with normal bilirubin postoperatively. Thus, we believe that until the age of 100 days, the age of the patients does not play a significant role in determining the success of the Kasai operation.
Increased Heat Shock Protein 72 Expression in Celiac Disease
Authors: Sziksz Erna , Veres Gábor , Vannay Ádám , Prókai Ágnes , Gál Krisztina , Ónody Anna , Korponay‐Szabó Ilma Rita , Reusz György , Szabó András , Tulassay Tivadar , Arató András , Szebeni Beáta
Published: September 2010

Background and Objectives:

Heat shock protein (HSP) 72, a known chaperone, has potential epithelial barrier protecting, antiapoptotic, and immune system regulatory effects; therefore, our aim was to study its involvement in the pathology of celiac disease (CD).

Patients and Methods:

Duodenal biopsy specimens were collected from children with untreated and treated CD and from controls. mRNA expression, protein level, and localization of HSP72 were determined.

Results:

Elevated HSP72 mRNA expression and higher protein levels were found in the duodenal mucosa of children with untreated CD as well as in children with treated CD compared with those in controls. In the duodenal mucosa of children with treated CD, HSP72 mRNA expression was decreased and HSP72 protein levels were lower than those in children with untreated CD. We detected intensive HSP72 staining in the villous enterocytes and immune cells of the lamina propria in the duodenal villi of children with untreated CD compared with that in controls.

Conclusions:

The increased expression and altered localization of HSP72 in CD indicate that HSP72 should have a role in protection against gliadin‐induced cytotoxicity. HSP72 may exert antiapoptotic effect and contribute to preservation of intestinal epithelial barrier integrity. Moreover, HSP72 as a ligand of TLR2 and TLR4 may promote innate immune responses and warn the cells of the potential injury.
Charge density distribution in aminomethylphosphonic acid
Authors: Janicki Rafał , Starynowicz Przemysław
Published: September 2010

The experimental charge density distribution in aminomethylphosphonic acid has been determined from X-ray diffraction and its topological features have been analyzed. The results have shown that the P—O bonds are highly polarized, moreover the P—OH bond is weaker than the bonds to unprotonated O atoms. These facts have been confirmed by theoretical density functional theory (DFT) calculations, which have shown that the single, strongly polarized bonds within the phosphonate group are modified by hyperconjugation effects.
Single-crystal neutron diffraction investigation on crystals belonging to the langasite family: a comparative study
Authors: Chitra R. , Choudhury R. R.
Published: September 2010

Crystals of the langasite family are of interest as they are piezoelectric in different devices. The properties of these classes of crystals can be modified within certain limits by isomorphous substitution. Single-crystal neutron diffraction studies were carried out for LGT (La3Ga5.5Ta0.5O14), LGST (La3Ga5.25Ta0.25Si0.5O14) and LGZrT (La3Ga5.25Ta0.25Zr0.5O14) as the neutron study gives a better average picture of the crystal properties over a macroscopic region of the grown crystal. The effect of small substitutions at various sites on the piezoelectric properties of the crystal was studied.
Role of interleukin‐17 in lymphangiogenesis in non‐small‐cell lung cancer: Enhanced production of vascular endothelial growth factor C in non‐small‐cell lung carcinoma cells
Authors: Chen Xi , Xie Qichao , Cheng Xiaoming , Diao Xinwei , Cheng Yue , Liu Jiankun , Xie Wei , Chen Zhengtang , Zhu Bo
Published: September 2010

Interleukin‐17 (IL‐17), a potent pro‐inflammatory cytokine, plays an active role in inflammation and cancer. Recently, we found that increased IL‐17‐producing cells correlate with poor survival and increased lymphangiogenesis in non‐small‐cell lung cancer (NSCLC), but the mechanism is unknown. Here, we show that IL‐17 promotes lymphangiogenesis via inducing vascular endothelial growth factor‐C (VEGF‐C) production by lung cancer cells. We found that IL‐17 receptor (IL‐17R) is expressed on the surface of Lewis lung carcinoma (LLC) cells but not on lymphatic endothelial cells (LEC). Moreover, LEC chemotaxis and tube formation (measures of net lymphangiogenic potential) were increased by conditioned medium from recombinant mouse IL‐17 (rmIL‐17)‐stimulated LLC but not by rmIL‐17. Interleukin‐17 increased production of VEGF‐C in lung cancer cell lines. The enhanced chemotaxis and endothelial cord formation in the presence of LLC/rmIL‐17 was inhibited by addition of recombinant mouse VEGF R3/Fc chimera. Treatment of the A549 cells with rIL‐17 significantly increased VEGF‐C expression, which was extracellular signal‐regulated protein kinase 1/2 (ERK 1/2) dependent. Importantly, we found significant correlations between IL‐17 expression, VEGF‐C expression and lymphatic vascular density (LVD) in NSCLC. We conclude that IL‐17 is involved in lymphangiogenesis in NSCLC by enhancing production of VEGF‐C, and IL‐17 may be an important target for the treatment of NSCLC. (Cancer Sci 2010; 101: 2384–2390)
Analysis of low frequency bleeding data: the association of joint bleeds according to baseline FVIII activity levels
Authors: DEN UIJL I. E. M. , FISCHER K. , VAN DER BOM J. G. , GROBBEE D. E. , ROSENDAAL F. R. , PLUG I.
Published: September 2010

Summary.  Many studies in the field of haemophilia and other coagulation deficiencies require analyses of bleeding frequencies. In haemophilia, the association of bleeding frequency with factor VIII (FVIII) activity levels is known from experience, but significant results are lacking. Bleeding frequencies in haemophilia are highly skewed count data, with large proportions of zeros. Both the skewness and the high amount of zeros pose a problem for standard (linear) modelling techniques. This study investigated the optimal analysing strategy for bleeding data by using the association of residual clotting factor level and number of joint bleeds in moderate and mild patients treated on demand as example. In total, 433 patients with moderate (27%) and mild (73%) haemophilia A treated on demand were included in this study. One year of self‐reported data on joint bleed frequency and baseline clotting factor activity were analysed using Poisson, negative binomial, zero‐inflated Poisson, and zero‐inflated negative binomial distributions. Multivariate regression analysis using negative binomial distribution provided the optimum data analytical strategy. This model showed 18% reduction [Rate ratio (RR) 0.82; 95%confidence interval (CI) 0.77–0.86] of bleeding frequency with every IU dL‐1 increase in residual FVIII activity. The actual association is expected to be higher because of exclusion (30 out of 463 patients) of patients on prophylaxis (baseline FVIII levels 0.01–0.06 IU mL−1). The best way to analyse low frequency bleeding data is using a negative binomial distribution.
Nursing students’ experiences of their first encounter with death during clinical practice in Taiwan
Authors: Huang Xuan‐Yi , Chang Jen‐Yu , Sun Fan‐Ko , Ma Wei‐Fen
Published: September 2010

Aims and objectives.  The aim of this study was to elucidate the experiences of first encountering death by nursing students during clinical practice. The objective is to assist nursing educational and clinical professionals to provide essential assistance for nursing students who encounter patient death.

Background.  Increasingly, deaths are occurring in hospitals. However, there has been little qualitative research in Taiwan on the experiences of nursing students who encounter patient death for the first time.

Design.  A descriptive qualitative method was employed to explore nursing students’ first experience with death during clinical practice in Taiwan.

Methods.  Purposive sampling, one‐on‐one, in‐depth with semi‐structured interviews were conducted to collect data. Participants were selected from an acute haematological ward in a major teaching hospital in Central Taiwan. Narratives were analysed using Colaizzi’s seven‐step method.

Results.  Data saturation was achieved after interviewing 12 nursing students. The average age of the students was 20, and seven and half days was the average time spent attending dying patients. Three themes and eleven sub‐themes were identified: Providing Care During the Dying Period (feelings of dread and terror, hardship of experiencing patient’s life fading away, devotion to patient care and self‐affirmation); Facing the Moment of Patient Death (state of being scared or trapped, emotional breakdown); Adjustment after Patient Death (acceptance or avoidance, growth or escape).

Conclusions.  Findings demonstrate the importance of understanding such first experiences, and the results are beneficial to clinical instructors and nursing personnel in understanding the students’ pressure and difficulties experienced before, during and after the patients’ death.

Relevance to clinical practice.  Several recommendations have been made, including teaching and support not only in the period of dying, but at the moment of patient death and postmortality. Avoiding topics about death in local culture have been noted.
A typology of bullying behaviours: the experiences of Australian nurses
Authors: Hutchinson Marie , Vickers Margaret H , Wilkes Lesley , Jackson Debra
Published: September 2010

Aim and objective.  This study sought to explore the nature of bullying in the Australian nursing workplace.

Background.  While there is widespread concern about the extent and consequences of bullying among nurses, to date, there have been no published reports cataloguing the types of behaviours that constitute bullying.

Design.  Reported here are findings from the first stage of a three‐stage sequential mixed methods study.

Methods.  The first, qualitative stage of this study employed in‐depth, semi structured interviews with 26 nurses who had experienced bullying from two Australian area health services. Content analysis of the verbatim interview transcripts was performed using the nvivo 7 software program.

Results.  The analysis identified six major categories and constituent sub‐categories. The typology of bullying behaviours reported here is one of these major categories.

Conclusion.  The typology of behaviours developed from the study provides detailed insights into the complexity of bullying experienced by nurses. The behaviours were labelled: personal attack, erosion of professional competence and reputation, and attack through work roles and tasks. These themes provide insight into the construct of bullying by providing a detailed catalogue of bullying behaviours that show that bullying is frequently masked in work tasks or work processes and focused on damaging the reputation and status of targets.

Relevance to clinical practice.  The detailed catalogue of bullying behaviours draws attention to the breadth of the bullying experience. It is anticipated the typology will be of use to nurses, managers and other professionals who are interested in responding to the problem of bullying in nursing.