bluuebunny/crossref_metadata_2025 huggingface dataset:
Graze to grain—measuring and modelling the effects of grazed pasture leys on soil nitrogen and sorghum yield on a Vertosol soil in the Australian subtropics
Authors: Whitbread A. M. , Clem R. L.
Published: May 2006

Highly productive sown pasture systems can result in high growth rates of beef cattle and lead to increases in soil nitrogen and the production of subsequent crops. The nitrogen dynamics and growth of grain sorghum following grazed annual legume leys or a grass pasture were investigated in a no-till system in the South Burnett district of Queensland. Two years of the tropical legumes Macrotyloma daltonii and Vigna trilobata (both self regenerating annual legumes) and Lablab purpureus (a resown annual legume) resulted in soil nitrate N (0–0.9 m depth), at sorghum sowing, ranging from 35 to 86 kg/ha compared with 4 kg/ha after pure grass pastures. Average grain sorghum production in the 4 cropping seasons following the grazed legume leys ranged from 2651 to 4012 kg/ha. Following the grass pasture, grain sorghum production in the first and second year was <1900 kg/ha and by the third year grain yield was comparable to the legume systems. Simulation studies utilising the farming systems model APSIM indicated that the soil N and water dynamics following 2-year ley phases could be closely represented over 4 years and the prediction of sorghum growth during this time was reasonable. In simulated unfertilised sorghum crops grown from 1954 to 2004, grain yield did not exceed 1500 kg/ha in 50% of seasons following a grass pasture, while following 2-year legume leys, grain exceeded 3000 kg/ha in 80% of seasons. It was concluded that mixed farming systems that utilise short term legume-based pastures for beef production in rotation with crop production enterprises can be highly productive.
Tulbaghia violacea L. I: In vitro antimicrobial properties towards plant pathogens
Authors: Nteso Leeto , Pretorius Johan C.
Published: May 2006

The antimicrobial properties of crude methanol extracts of above- and below-soil parts of Tulbaghia violacea were quantified by means of an agar diffusion method against 6 plant pathogenic bacteria and 7 fungi. The growth of 3 out of the 6 bacteria, Clavibacter michiganensis, Ralstonia solanacearum, and Xanthomonas campestris, was significantly inhibited by crude extracts of both below-soil and aerial parts of T. violacea, whereas the growth of Pseudomonas syringae, Erwinia carotovora, and Agrobacterium tumefaciens was unaffectedl. Compared with the standard fungicide, both the aerial and below-soil extracts of T. violacea significantly inhibited the mycelial growth of 6 of the 7 test fungi, Botrytis cinerea, Sclerotium rolfsii, Rhizoctonia solani, Mycosphaerella pinodes, Botryosphaeria dothidea, and P. ultimum, whereas only the below-soil extract inhibited the mycelial growth of Fusarium oxysporum significantly. The broad-spectrum antifungal activity shown by the crude T. violaceae extracts supplied a rationale for a further investigation into the in vivo activity of the extracts under glasshouse and field conditions.
Summer dormancy in Dactylis glomerata L.: the influence of season of sowing and a simulated mid-summer storm on two contrasting cultivars
Authors: Norton M. R. , Lelièvre F. , Volaire F.
Published: May 2006

A series of trials to increase understanding of the summer dormancy trait in Dactylis glomerata was conducted. Autumn-sown reproductive and younger, spring-sown plants of 2 drought-resistant cultivars, contrasting for summer dormancy, were established and then tested in summer 2002 under long drought, drought + mid-summer storm, or full irrigation. The autumn-sown reproductive plants of cv. Kasbah were summer dormant under all moisture regimes and exhibited the characteristic traits including growth cessation, rapid herbage senescence, and dehydration of surviving organs (–6.7 MPa). Cultivar Kasbah used 8% less soil water over the summer and also began to rehydrate its leaf bases from conserved soil water before the drought broke. The non-dormant cv. Medly grew for 10 days longer under drought and whenever moisture was applied; Medly also responded to the storm with a decline in dehydrin expression in leaf bases, whereas no decline occurred in Kasbah, presumably because it remained dormant and therefore much drier. The irrigated, younger, spring-sown swards of cv. Kasbah had restrained growth and produced only about 25% of the herbage of cv. Medly. Drought reduced activity and growth of young plants of both cultivars, but whereas Medly regrew in response to the storm, cv. Kasbah did not, indicating that dormancy, although only partially expressed after spring sowing, was reinforced by summer drought. A longer drought in 2003 caused a 22% loss of the basal cover in cv. Medly, whereas Kasbah fully maintained its sward and therefore produced a higher post-drought autumn yield. This work confirms summer dormancy as a powerful trait for improving persistence over long, dry summers.
Effect of the puroindoline locus and environment on Chinese fresh noodle texture
Authors: Storlie E. , Yang E. N. , Zou Y. C. , Chen D. S. , Sheppard J. , Martin D. , Huang S. , Mares D. , Sutherland M. W.
Published: May 2006

Grain produced from doubled-haploid (DH) wheat lines, developed from a hard- and a soft-grained wheat cultivar, were bulked according to Pinb (puroindoline b) genotypes for an assessment of Chinese fresh noodle texture by a trained taste panel. Each DH line was designated as ‘soft’ or ‘hard’ grained, based on a PCR amplification of the wildtype, soft allele, or the mutant, hard allele. Theoretically, the soft and hard grain bulks represented respective Pinb alleles and an independent assortment of unlinked alleles from the parents, Sunco and Chuanyu 12. Grains from the parents and DH lines were grown at 2 locations in Queensland, Australia, and one in Sichuan, China. The grains were milled and processed for a taste panel evaluation in Chengdu, Sichuan. Results suggest the Pinb alleles had a significant effect on noodle softness and explained 30% of the variation; the ‘soft’ Pinb allele conferred a softer noodle texture. Location had a significant effect on noodle smoothness; wheat grain grown at Biloela, Queensland, produced a smoother noodle texture than grain grown in Sichuan. The effect of location confirms the importance of environment as a variable for this quality character. This investigation exemplifies the utility of Pinb markers for specifically altering Chinese Fresh Noodle texture.
Tulbaghia violacea L. II: In vivo antifungal properties towards plant pathogens
Authors: Nteso Leeto , Pretorius Johan C.
Published: May 2006

In vitro antifungal activity of crude extracts from Tulbaghia violacea against 6 economically important plant pathogenic fungi was previously reported. The in vivo control of Mycosphaerella pinodes, causative of Ascochyta blight, by different concentrations of a crude aerial part extract of T. violacea was subsequently followed qualitatively and quantitatively in terms of lesions that developed over a 6-day period at 20°C on detached pea (Pisum sativum) leaves. Infection by M. pinodes spores was prevented when the extract was applied both before and after inoculation, confirming complete inhibition of spore germination, whereas no phytotoxic effect was observed on the leaves. Additionally, the control of sorghum covered (Sporisorium sorghi) and loose (S. cruentum) kernel smuts by seed treatment with the crude extract was tested under field conditions. Before planting, different sorghum seed lots were inoculated separately with spores from the 2 pathogens at a rate of 0.5% per kg (w/w), followed by treatment with the crude extract, at a concentration of 2.0 mg/mL, 24 h later. A standard fungicide, Thiram (65 W), was applied as a positive control at a rate of 0.25% per kg (v/w). Disease incidence was quantified during harvest and expressed as percentage infected plants. Seed treatment with the extract significantly (P < 0.05) reduced the incidence of both sorghum loose and covered smut diseases, compared favourably with the standard fungicide, and resulted in significant yield increases compared to the untreated control.
Environmental impact of conventional and Bt insecticidal cotton expressing one and two Cry genes in Australia
Authors: Knox Oliver G. G. , Constable Greg A. , Pyke Bruce , Gupta V. V. S. R.
Published: May 2006

Genetically modified Bt cotton, expressing the Cry1Ac protein for specific insecticidal activity against economically significant lepidopteran pests, has been available commercially in Australia since 1996. This technology has been improved and superseded by the addition of a second gene, allowing new varieties to express both the Cry1Ac the Cry2Ab proteins.
Bt cotton offers several advantages to the grower, mainly through reduced insecticide spray requirements. The environmental benefits of reduced insecticide usage are assessed in this paper using the environmental impact quotient (EIQ). The assessment included consideration of the impact of the expressed transgenic proteins Cry1Ac and Cry2Ab. EIQ values of the Cry1Ac and Cry2Ab proteins were calculated at 9.9 and 7.9, respectively. Bt protein expression, plant biomass, insecticide application records, constituent of active ingredient, and insecticide EIQ values were used to produce an environmental impact (EI) value for insecticide use (kg a.i./ha) for conventional non-GM and single- and 2-gene Bt cotton for the 1997–98 to 2003–04 seasons. Inclusion of the Cry proteins in the assessment increased the EI values for Bt cotton by only 2%. The average insecticide EI value, for 2002–03 and 2003–04 seasons, for conventional cotton was 135 kg a.i./ha, whereas for the 2-gene Bt variety it was only 28 kg a.i./ha. Results of the EI evaluation indicate that, due to changes in insecticidal choice and reduction in usage, there was a reduction of >64% in EI from growing Bt cotton compared with conventional non-GM cotton in Australia.
Spectrum of azulene. VI. Centrifugal distortion and the inertial defect
Authors: McHugh AJ , Ross IG
Published: May 2006

The published microwave
spectrum of azulene is re-analysed to yield the following values of the
centrifugal distortion constants (units of kHz): Taaaa -1.45�0.76; Tbbbb
-0.05�0.07; Taabb +0.70�0.42; Tabab -0.47�0.17. ��� The inertial defect Δ = Ic-Ia-Ib,
typically positive in monocyclic compounds, is negative in azulene. According
to the theory of Oka and Morino,
the largest contribution to Δ is the vibrational part, which depends on
the frequencies of the normal vibrations and on the Coriolis coupling constants.
For the latter, a modified ?uniform coupling? approximation is proposed, based
on sum rules applicable to planar molecules. Calculations are then carried out
on pyridine, naphthalene, and azulene in which the change of sign of Δ, in
two-ring, and presumably larger, aromatics is traced to the influence of low- frequency
out-of-plane vibrations. For azulene, the values of Δ in a vibrationally
excited state and an electronically excited state are also considered.
Time resolved electronic spectroscopy. I. Bimolecular rates for excimer formation
Authors: Speed R , Selinge r
Published: May 2006

The time delay in the
build-up of excimer fluorescence for solutions of pyrene affords a means of
testing the assumption that bimolecular quenching of fluorescence is
diffusion-controlled. It appears that in solvents of low viscosity this is no
longer the case. An apparatus is described with which measurements of
fluorescence intensity at nanosecond intervals can be made using a simple
versatile high- intensity lamp of short flash duration.
N-Substituted salicylaldimine complexes of manganese(III). Synthesis, magnetism, and spectra
Authors: van den Bergen A , Murray KS , O'Conner MJ , West BO
Published: May 2006

Complexes of manganese(III)
and N-substituted salicylaldimines have been prepared of general formulae
Mn(sal-NR)3 and Nn(sal-NR)2X (X = Cl, Br, OAc). The
complexes show high-spin magnetic behaviour with small deviations of the
susceptibilities from the Curie law. Complexes of the type Mn(salen)X(X = Br,
I) have also been studied and these show somewhat larger deviations from Curie
behaviour. It is difficult to interpret this Curie-Weiss behaviour with
certainty, but it can be explained for the salen derivatives, in particular, in
terms of very weak antiferromagnetic interactions. The visible and
near-infrared spectra for all the complexes are assigned. A Jahn-Teller
splitting of the d-d transition is observed. Comparison of the i.r. spectra of
the M(sal)3 derivatives (M = CrIII, MnIII, and
FeIII) in the region 700-250 cm-1 has enabled assignments
of the v(M-O) modes to be made. The spectra suggest that a Jahn-Teller distortion
is operative in the Mn(sal)3 complex.
Trispentafluorophenylsilane and trispentafluorophenylsilyl-metal derivatives. Preparation, and infrared and mass spectra
Authors: Schrieke RR , West BO
Published: May 2006

Trispentafluorophenylsilane has been prepared and characterized. The silane has
been used to prepare the monohalides, (C6F5)3SiX (X = Cl, Br), as
well as the disiloxane, (C6F5)3Si-O-Si(C6F5)3.
The silane has also been found to react with the binuclear metal carbonyls Co2(CO)8 and M2(CO)10
(M = Mn, Re) to yield the silyl-metal
derivatives. We report the preparation and infrared and mass spectra of these
compounds, and their reactivity towards triphenylphosphine.
Some studies in inorganic complexes. XXII. Reactions of nickel(II) with chelating heterocyclic bases
Authors: Nicholoson AR , Sutton GJ
Published: May 2006

Spin-free six-coordinate
complexes of nickel(II) and the heterocyclic ligands 2-aminomethylpyridine, 2-methylaminomethylpyridine, 2-(2- aminoethyl)pyridine, and
2-aminomethyl-6-methylpyridine have been prepared and studied. Various hydrated
and anhydrous nickel(II) complexes with the anions sulphate, nitrate, halide,
and perchlorate were obtained with nickel ion to ligand stoicheiometric ratios
of 1 : 1, 1 : 2, and 1 : 3, and in a number of instances water molecule and
anion attachments to the coordination sphere are reported; the sulphate
complexes are considered to be of the bridged type. Also, certain mixed-ligand
solid complexes and mixed-ligand cationic species in aqueous solution were
prepared. Physical measurements used to elucidate structures included molecular
conductances in suitable solvents, solubility observations, infrared
spectrophotometry, pyrolysis methods, and measurements of magnetic
susceptibility. Complex cations in aqueous solution were characterized by
visible and near-infrared spectrophotometry.
Deprotonation of metal complexes derived from ligands containing the 2-pyridylhydrazine residue
Authors: Chiswell B , Lions F
Published: May 2006

A number of new bidentate,
tridentate, and sexadentate ligands derived from 2-pyridylhydrazine have been
prepared and their metal complexes isolated. Such complexes have been shown
capable of deprotonation, by removal of a proton from the hydrazine chain, to
yield intensely coloured compounds soluble in organic solvents. Some of the
deprotonated cobalt(II) and nickel(II) complexes have sub-normal magnetic
moments. A summary of the classes of compounds that will undergo deprotonation
of this type, and of the properties of such deprotonated complexes, is given
with reference to other papers on this topic.
The uncatalysed, and the imidazole and o-mercaptobenzoic acid catalysed, hydrolysis of p-nitrophenyl N-benzyloxycarbonylglycinate
Authors: Hay RW , Trethewey RJ
Published: May 2006

The uncatalysed hydrolysis
of p-nitrophenyl N- benzyloxycarbonylglycinate has been studied in 40% (v/v)
ethanol-water over the pH range 7.6-8.5. The reaction shows a first-order
dependence on the hydroxide ion concentration. The quite rapid hydrolysis (k =
(4.4�0.4) x 104 1. mole-1 min-1 at 20�) may
possibly indicate the formation of a 2-benzyloxyoxazoline-5-one intermediate. ��� Unlike the hydrolysis of the p-nitrophenyl
esters of α-amino acids, the hydrolysis of the N-protected derivatives is
not catalysed by carbon dioxide. The hydrolysis of p-nitrophenyl N- benzyloxycarbonylglycinate
is, however, catalysed by imidazole in 40% v/v ethanol-water. Unprotonated
imidazole (Im) is the catalytically active species.
N-Benzyloxycarbonylaminoacetylimidazole has been detected
spectrophotometrically as an intermediate in the reaction, indicating
nucleophilic catalysis by the base. o-Mercaptobenzoic acid was also found to
catalyse the hydrolysis of p-nitrophenyl N- benzyloxycarbonylglycinate. pH-rate
profile studies indicate that the dianion of o-mercaptobenzoic acid is the
catalytically active species, the substrate presumably hydrolysing via the
thioester intermediate Z- NHCH2COSC6H4COO-,
although efforts to detect such an intermediate have been unsuccessful. Some
evidence for a thioester intermediate in the L- cysteine-catalysed reaction has
been obtained.
Studies of metal halides. Magnetic properties of some molybdenum(III) binuclear complex halides
Authors: Grey IE , Smith PW
Published: May 2006

The variation of magnetic
susceptibility with temperature for a number of binuclear halide complexes of
molybdenum of formula A3IMo2X9
(A = Cs, Et4N, Et3NH;
X = Cl, Br) has been studied over the range 90-400�K.
The magnetic behaviour is consistent with that expected for magnetically
isolated exchange-coupled pairs of molybdenum atoms. The coupling is
interpreted as occurring mainly by direct metal-metal interaction rather than
superexchange.
Bivalent cobalt complexes of 2,4,6-Tri(2'-pyridyl)-1,3,5-triazine
Authors: Warrener RN , Watton EC
Published: May 2006

This paper reports the
isolation of a series of new coordination compounds formed with the terdentate
ligand 2,4,6-tri(2?-pyridyl)- 1,3,5-triazine (tpt)
and various bivalent cobalt salts. The stereochemistries of these compounds are
proposed after consideration of their elementary analyses, visible solid and
solution spectra, infrared spectra, magnetic moments, and thermogravimetric
studies. ��� The chelates obtained include octahedral bis-complexes
of the type [Co tpt2]X2 (where
X = Cl, Br, I, CNS, ClO4,
NO3, BF4, or BPh4)
and five- coordinate mono-complexes of the type CoXz tpt (where X = Cl, Br, I, or
NCS). A third dimeric form is also reported of general formula Co2X4 tpt,nH2O
(where X = Cl, n = 0 or I; X = Br, n = 0 or 2). In
this latter form the ligand appears to function as a composite of both
terpyridine and bipyridine, showing simultaneous terdentate and bidentate
behaviour, with one cobalt atom in either a five-coordinate or six- coordinate
environment, and the other metal atom involved in tetrahedral coordination. ��� In general the compounds formed are
high-spin with normal room- temperature magnetic moments. The single exception
is the red octahedral complex [Co tpt2]Cl2, 8.5H2O, which has a
room-temperature moment of only 4.0 B.M.
Electron impact studies. XL. Negative-ion mass spectra of organosulphur compounds : Thioglycollic acids and arylsulphinylamines
Authors: Bowie JH , Duus F , Lawesson S , Larsson FCV , Madsen J+
Published: May 2006

The negative-ion mass
spectra of thioglycollic esters and S- alkylthioglycollic
acids exhibit ions produced by simple cleavage and/or cleavage with hydrogen
rearrangement. Similar spectra of arylsulphinylamines show pronounced molecular
ions together with simple cleavage fragments. No skeletal-rearrangement
fragments are present in the negative-ion spectra, in marked contrast with
those observed in the corresponding positive-ion spectra.
Hydroxamic acids. II. The acetylation of O-alkylhydroxamic acids
Authors: Hearn MTW , Ward AD
Published: May 2006

O-Alkylhydroxamic acids are
readily acetylated, in high yield, under mild conditions. Aliphatic
O-alkylhydroxamic acids yield only one product, shown to be the N-acetyl
derivative. O-Alkylarylhydroxamic acids form both the O- and N- acetyl isomers;
the ratio of these isomers depends on electronic and steric effects.
Ultraviolet spectral data indicate that the salts of O-alkylarylhydroxamic
acids exist predominantly in the hydroximic acid form; however, it is not
possible to decide which is the acidic proton of the hydroxamic acid system.
The nature of the cation in the salts of O-alkylhydroxamic acids is important
in determining the site of acetylation.
Hydroxamic acids. III. Mass spectra of substituted hydroxamic acids and cyclic imides
Authors: Bowie JH , Hearn MTW , Ward AD
Published: May 2006

Aryl hydroxamic acid
derivatives fragment in a diagnostic manner upon electron impact. A hydroxamic
acid containing both styryl and benzyl substituents undergoes skeletal-rearrangement
of the type ABC → AC+B. The mass spectra of the O- and N-acetyl derivatives
of O- benzylhydroxamic acids are indistinguishable. M-CO2 fragments
are again observed in the mass spectra of several substituted phthalimides.
Regulators of cell division in plant tissues. VII. The synthesis of zeatin and related 6-substituted purines
Authors: Letham DS , Mitchell RE , Cebalo T , Stanton DW
Published: May 2006

6-(4-Hydroxy-3-methylbut-trans-2-enylamino)purine
(zeatin), a cytokinin isolated from Zea mays, has been synthesized by a new route. β- Methylcrotononitrile was brominated with N-bromosuccinimide
yielding γ- bromo-β-methylcrotononitrile,
from which trans-γ-acetoxy-β- methylcrotononitrile
was prepared. The alcohol derived from this acetate was converted into
trans-β-methyl-γ-(tetrahydropyran-2- yloxy)crotononitrile. Reduction and acid hydrolysis gave
4-amino-2- methylbut-trans-2-en-1-ol which was made
to react with 6-chloropurine to yield zeatin. ��� Several γ-alkoxy-β-methylcrotononitriles were prepared and reduced by
aluminium chloride-lithium aluminium hydride to the corresponding unsaturated
amines. Saturated nitrile formation also occurred in these reductions. The
amines prepared were condensed with 6-chloropurine to yield a series of O-alkylzeatins.
A number of other zeatin analogues were also synthesized. Two
6-methoxyalkylamino-purines were cleaved by sodium borohydride in the presence
of iodine to 6-hydroxy- alkylaminopurines.
The chemistry of pyrrolic compounds. VII. Synthesis of 5,5'-diformyldipyrryl-methanes
Authors: Chong R , Clezy PS , Liepa AJ , Nichol AW
Published: May 2006

The preparation of a number
of 5,5?-diformyldipyrrylmethanes is described using benzoyl
chloride-N,N-dimethylformamide as the formylating mixture.
The chemistry of pyrrolic compounds. VIII. Dipyrrylthiones
Authors: Clezy PS , Smythe GA
Published: May 2006

A number of symmetrical
dipyrrylthiones have been prepared by the action of thiophosgene on the
appropriate 5-unsubstituted pyrrole. From an examination of their spectroscopic
properties it is concluded that these compounds exist predominantly as the
thione tautomer. Some chemical properties of the system are described including
the conversion of the thiones into ketones by treatment with alkaline peroxide.
The mass spectra of dipyrrylthiones and dipyrrylketones are compared.
Dithiocarbamates as Innocent Anions: The Synthesis and Structural Properties of (8-Methyl-3,6,10,13,16,19-hexaazabicyclo[6.6.6]-icosan-1-amine)cobalt(Ii I) Tris(N,N-diethyldithiocarbamate), [Co(AMMEsar)][Et2dtc]3
Authors: Gahan LR , Hambley TW , Healy PC
Published: May 2006

Sodium diethyldithiocarbamate, Na[Et2dtc], reacts with (8-methyl-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosan-1-aminium)cobalt(III) chloride, [Co( AMMEsarH )]Cl4, in aqueous solution to form the compound [Co( AMMEsar )][Et2dtc]3 which is readily soluble in organic solvents. Crystals are trigonal, space group R3c (3m, No. 167) with a 13.864(4), c 36.42(2)Ǻ, Z 6. A full-matrix least-squares refinement on 952 reflections, with I > 2.5σ(I), converged with final R of 0.037. The structure consists of the [Co( AMMEsar )]3+ cation and three [Et2dtc]- anions. The primary aminium group on one trigonal cap of the cage is deprotonated to an amine. Strong hydrogen bonds exist between the sulfur atoms of the diethyldithiocarbamate anions and the protons of the secondary amines of the complex cation, which is stabilized in the lel conformation.
The Crystal and Molecular Structure of Chloro-mer-Tris(dimethylphenylphosphine)-cis-dihydridoiridium(III) by X-Ray and Neutron Diffraction
Authors: Robertson GB , Tucker PA
Published: May 2006

The structure of mer-(Pme2Ph)3Cl-cis-H2IrIII (1) has been determined by single-crystal X-ray and neutron diffraction analyses. Crystals are monoclinic, space group P21, with a 11.476(4), b 14.069(5), c 8.286(3)Ǻ, β 92.45(1)° and Z 2. Full-matrix least-squares analyses converged 0.022 for 7773 X-ray data and R(F2) = 0.062 for 1538 neutron data. Ir -H [1.557(11)Ǻ trans to Cl, 1.603(10) Ǻ trans to P] and Ir -P distances [2.292(1)Ǻ trans to P, 2.328(1)Ǻ trans to H] both exhibit trans lengthening effects. Consistent with the increased hydride content the Ir -P distances in (1) are c. 0.04 Ǻ shorter than for the corresponding bonds in its dichloro monohydrido analogues and c. 0.08 Ǻ shorter than those in the trichloride . In contrast Ir-Cl [2.505(1)Ǻ] is not significantly different to the corresponding distance (2.504 Ǻ av.) in mer -(PMe2Ph)3-cis-Cl2HIrIII.
Synthetic and Structural Studies of Binuclear Organopalladium(II) Complexes Including a Bis(pyridin-2-yl)phenylmethyl Complex With Four- and Eight-Membered Palladocycle Rings, trans(N,N)-(Pd(μ-Py2PhC-N,N',C')Cl)2.½CH2Cl2.½Me2CO
Authors: Canty AJ , Minchin NJ , Engelhardt LM , Skelton BW , White AH
Published: May 2006

The byridin-2-yl) phenylchloromethanes PyPh2CCl and Py2PhCCl undergo oxidative addition reactions with bis ( dibenzylideneacetone )palladium(0) to form {Pd(PyPh2C) Cl }2 (1) and {Pd(Py2PhC)C}2.�2CH2Cl2.�Me2CO (2), respectively. n.m.r , studies of (1) in CDCl3 indicate presence of an equilibrium between two isomers, involving the ligand (pyridin-2-yl ) diphenylmethyl in η3-coordination, {Pd(η3-PyPh2C)(μ- Cl )}2. Complex (2) has two bis (pyridin-2-yl) phenylmethyl groups present as bridging N,C′- ligands , with the groups also N,C- bidentate to each palladium, to form a binuclear compex containing four- and eight- membered palladocycles: PdC(CN)CNPdC(CN)CNBoth palladium(II) centres in (2) have square-planar 'trans-PdCN2Cl' coordination, so that (2) may be represented as trans(N,N)-{Pd(μ- Py2PhC-N,N′, C′) Cl }2.�CH2Cl2.�Me2CO. A complex similar to (2), trans(N,N)-{Pd(μ- PyPhCH -N,C?)( γmpy ) Cl }2.CH2Cl2 (3), forms on reaction of the lithium derivative of 2-benzylpyridine, Li( PyPhCH ), with dichlorobis (4-methylpyridine)palladium(II); (3) reacts with excess 2-benzylpyridine with displacement of γmpy to form trans(N,N)-{Pd(μ- PyPhCH -N,C?)(PyPhCH2) Cl }2 (4). In developing an alternative isolation procedure for (3), involving column chromatography with 4% ethyl acetate in chloroform, the coordination complex trans- bis{1-phenyl-1-(pyridin-2-yl)prop-1-en-2-olato-O,N}palladium(II), Pd{( PyPhC )C(Me)O}2 (5), was isolated in low yield. X-Ray structural studies of (2)-(5) have been completed, with all four complexes crystallizing in the monoclinic system; (2): space group P21/c, a 9.649(6), b 21.116(9), c 18.627(7)Ǻ,β 111.42(4)°, Z 4; (3): P21/c, a 13.967(2), b 13.996(3), c 18.886(2)Ǻ, β 98.74(1)°, Z 4; (4): P21/n, a 14.274(9), b 14.584(14), c 20.97(2)Ǻ, β 109.18(5)°, Z 4; (5): P21/c, a 15.184(3), b 7.887(6), c 19.240(2)Ǻ, β 97.51(1)°, Z 4.
The Synthesis of 6-Aminomethyl-5,6,7,8-Tetrahydropterin
Authors: Waring P
Published: May 2006

6-Aminomethyl-5,6,7,8-tetrahydropterin has been prepared by reduction of 2-acetamido-6-cyanopteridin-4(3H)-one* to 2-acetamido-6-aminomethyl- 5,6,7,8-tetrahydropteridin-4(3H)-one followed by acid hydrolysis. The hitherto undescribed 6-cyanopterin was prepared by careful hydrolysis of the 2-acetamido compound prepared by dehydration of the oxime derived from 2-acetamido-6-formylpteridin-4(3H)-one. The latter was prepared by selenium dioxide oxidation of the methyl compound. Oxidation of 6-aminomethyl-5,6,7,8-tetrahydropterin at neutral pH appears to proceed with significant side-chain loss in Tris buffer but not in phosphate buffer.
Hydrolysis of Cinnamoyl Fluoride Catalyzed by Micelles of a Copper(II) Complex
Authors: Gan LH
Published: May 2006

Cinnamoyl fluoride was catalytically hydrolysed in the micelles formed by the copper(II) complex of N,N,N°- trimethyl -N°- tetradecylethylenediamine . A 25-times rate enhancement relative to the reaction in the micelles of hexadecyltrimethylammonium chloride was observed, but it was not as good a simulant as p- nitrophenyl diphenyl phosphate for nerve agents of the soman type. It was also found that aggregation of the copper(II) complex was essential in promoting the reactivity as the monomeric copper(II) complex of N, N, N′, N′- tetramethylethylenediamine had very little effect on the hydrolysis rate.
Dimerization of Glycine Derivatives
Authors: Burgess VA , Easton CJ , Hay MP , Steel PJ
Published: May 2006

The bromide (5), prepared by treatment of the glycine derivative (4) with N-bromosuccinimide, reacted with hexabutylditin to give diastereoisomers of the glycine dimer (7), only when moisture was rigorously excluded from the reaction. Otherwise the major products were the diastereoisomers of the ether (11). The structure of the racemic diastereoisomer (11) was determined by X-ray crystallography. Photolysis of mixtures of the glycine derivative (4) and di-t-butyl peroxide gave the alanine derivative (10) in addition to the diastereoisomeric dimers (7).
Ozonolysis of Derivatives of Labda-8(17),14-dien-13-ol (Manool) and Their Conversion Into Large Ring Unsaturated Lactones
Authors: Grant PK , Chee KL , Prasad JS , Tho MY
Published: May 2006

Dehydration of the unstable hydroperoxy ethers (4) and (6) formed on ozonolysis of the manool derivatives (2) and (5) resulted in the formation of the ten- membered unsaturated lactones (11) and (12) in good yield. The results of an investigation into the nature of the hydroxyl group and its spatial relationship to the exocyclic double bond in lactone formation are reported for other manool derivatives.
Base-Catalyzed Self-Condensation of Arylacetaldehydes: Molecular Structures of (E)-2,4-Bis(9-Anthryl)but-2-enal and (E)-2,4-Diphenylbut-2-enal
Authors: Axelsson O , Becker HD , Skelton BW , Sorenson H , White AH
Published: May 2006

Both 9-anthrylacetaldehyde and phenylacetaldehyde undergo stereoselective self-condensation in the presence of base to give (E)- 2,4-di(9-anthryl)but-2-enal (2a), and (E)-2,4-diphenylbut-2-enal (2b) respectively, as established by single-crystal X-ray structure determination. Crystals of (2a) are monoclinic, P21/n, Z 8, a 10.638(9), b 20.68(1), c 20.41(2)Ǻ, β 92.36(5)°; R was 0.061 for No 3476 'observed' reflections. Crystals of (2b) are monoclinic, P21/c, Z 4, a 5.781(2), b 23.163(8), c 9.297(5)Ǻ, β 91.54(4)°; R 0.037 for No 1174. In both compounds, the enal moiety assumes a virtually planar s-trans conformation, with the angles between the planes of the olefinic double bond and the adjacent aromatic π-system around 70°.
The Structure and Function of Estrogens. IX. Synthesis of the trans Isomer of 5,5,10b-Trimethyl-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol
Authors: Collins DJ , Cullen JD
Published: May 2006

Alkylation of ketene methyl trimethylsilyl acetal (10) with 1ξ-acetoxy- 6-methoxy-2-(p- methoxyphenyl )-2-methyl-1,2,3,4-tetrahydronaphthalene (9) in the presence of zinc iodide gave 84% of methyl (1′RS,2′RS)-2- [6′-methoxy-2′-(p-methoxyphenyl )-2?-methyl-1′,2′,3′,4′- tetrahydronaphthalen-1′-yl] ethanoate (11a). Cyclization of the derived acid (11b) with methanesulfonic acid gave 89% of 2,8-dimethoxy-10b-methyl-cis-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (12a), Clemmensen reduction of which afforded 52% of 2,8-dimethoxy-4b-methyl-cis- 4b,5,6,10b,11,12-hexahydrochrysene (12b). Oxidation of (12b) with dichlorodicyanobenzoquinone gave 70% of the conjugated enone (4), which upon hydrogenation over 10% palladium/charcoal gave a 5:1 ratio of 2,8-dimethoxy-10b-methyl-trans-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (14) and the cis isomer (12a). Exhaustive methylation of the trans ketone (14) yielded 49% of 2,8-dimethoxy-5,5,10b-trimethyl-trans-4b,10b,11,12-tetrahydrochrysen-6(5H)-one (16), which upon Clemmensen reduction followed by O- demethylation afforded 5,5,10b-trimethyl-trans-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol(2).
The Structure and Function of Estrogens .10. Synthesis of 5,5-Dimethyl-Cis-4b,5,6,10b,11,12-Hexahydrochrysene-2,8-Diol - the Estrogenic Activity of This and of Related C-Methylated Hydrochrysenediols
Authors: Collins DJ , Cullen JD , Stone GM
Published: May 2006

Reaction of 6-methoxy-2-(p- methoxyphenyl )-3,4-dihydronaphthalen-1(2H)- one (9) with dimethylketene ethyl trimethylsilyl
acetal (10) in the presence of titanium tetrachloride
gave ethyl 2-methyl-2-[6?-methoxy- 2?-(p- methoxyphenyl )-3?,4?-dihydronaphthalen-1?-yl] propanoate (11) which upon treatment with methanesulfonic acid afforded the lactone
(13). Reduction of (11) with lithium/ammonia yielded mainly 6-methoxy- 2-(p- methoxyphenyl )-1,2,3,4-tetrahydronaphthalene (16), but
hydrogenation of (11) over palladium/charcoal gave 61% of ethyl
(1?RS,2?RS)-2-methyl-2-[6?-methoxy-2?-(p- methoxyphenyl )-1?,2?,3?,4?-

(tetrahydronaphthalen-1?-yl] propanoate (21a). Alternatively, the ester (21a) was
prepared in three steps from the ketone (9) by
reaction of the derived 1ξ-acetoxy-6-methoxy-2ξ-(p- methoxyphenyl )-1,2,3,4- tetrahydronaphthalene
(20b) with the ketene silyl acetal
(10) in the presence of zinc iodide. Treatment of the ester (21a) with methanesulfonic acid afforded 72% of
2,8-dimethoxy-5,5-dimethyl-cis-4b, 10b,11,12-tetrahydrochrysen-6(5H)-one (22)
which was converted into
2,8-dimethoxy-5,5-dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene (23) in 63%
yield via the dithiolan (24). Demethylation
of (23) gave 5,5- dimethyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol (3a).

��� Assays of the oestrogenic
activity of compound (3a), and of related hydrochrysenediols
are reported.
Syntheses and NMR-Studies of Cationic Mercury Xanthate, Dithiophosphate and Dithiocarbamate Tricyclohexylphosphine Adducts - the Crystal and Molecular-Structures of [Hg(S2cnet2)(P(C-C6h11)3)2]+ (Cf3so3)- [Hg(S2copri)(P(C-C6h11)3)2]+ (Clo4)-.ch2cl2 And [Hg(S2p(Opri)2)(P(C-C6h11)3)2]+ (Cf3so3)-
Authors: Abrahams BF , Dakternieks D , Hoskins BF , Winter G
Published: May 2006

Phosphorus-31 and
mercury-199 N.M.R . data are presented for the phosphine adducts Hg(S-S)(P(c-C6H11)3) nA (S-S = isopropylxanthate ( ipxan ), diisopropyl dithiophosphate ( dipdtp ), diethyldithiocarbamate ( dedtc ); n
= 1,2; A = CF3SO3, ClO4, S-S). When A = CF3SO3,
ClO4 and n = 1 or 2, the cationic species [Hg(S-S)P(c-C6H11)3]+
and [Hg(S-S)(P(c- C6H11)3)2]+
respectively are formed in which the S-S ligands act
as bidentate donors. When A = S-S and n = 2 there is
rapid exchange between the S-S ligands with the complexes
remaining four-coordinate, even at low temperature. The position of the dithiophosphate phosphorus-31 resonance for compounds with
S-S = dipdtp , reveals whether the dipdtp
ligand acts as a monodentate
or bidentate donor in solution.

��� The crystal structures of Hg( dedtc )(P(c-C6H11)3)2(CF3SO3),
Hg( ipxan )(P(c-C6H11)3)2(ClO4).CH2Cl2
and Hg( dipdtp )(P(c-C6H11)3)2(CF3SO3)
have been determined. Crystals of Hg( dedtc )(P(c-C6H11)3)2(CF3SO3)
are monoclinic, P21/c, a 11.100(3), b 31.508(7), c 14.998(2)Ǻ,
β 111.05(2)� Z 4. Crystals of Hg ( ipxan )(P(c-C6H11)3)2ClO4.CH2Cl2
are triclinic, Pī , a 13.604(5), b 13.734(3) c
14.666(5)Ǻ α 77.74(2)�,β 65.68(3)�, y 80.40(2)�, Z 2. Crystals
of Hg( dipdtp )(P(c-C6H11)3)2(CF3SO3)
are monoclinic, P21/c, a 10.440(2), b 22.615(4), c 21.904(3),β
93.05(1)�, Z 4. The observed deviation from the expected tetrahedral
environment of the mercury atom is discussed on the basis of ligand bite and steric
requirements.
The Crystal Size and Morphology of Silicalite as Influenced by Gel Nucleation Temperature, Alkalinity and Sodium-Chloride Concentration
Authors: Hill SG , Kinson K , Seddon D
Published: May 2006

The influence of sodium
chloride, nucleation temperature and alkalinity on crystal size and product
morphology of silicalite is described for
crystallizations at temperatures of about 170�C. Addition of sodium chloride
and increasing alkalinity produce crystals with less intergrowth. Nucleating
the gel at 90�C before crystallization significantly reduces crystal size. The
intergrowths on the faces of silicalite can be separated and features of the
interlocking of separate crystal entities revealed.
Viscosities and Densities of Binary-Mixtures of 2,2,2-Trichloroethanol With Substituted Anilines
Authors: Palepu R , Macneil JH
Published: May 2006

Densities and viscosities
of binary solvent mixtures containing 2,2,2-trichloroethanol as one component
and aniline and substituted anilines as the other components have been measured
over the whole composition range at 298, 303, 308, 313 and 318 K. The experimental
data are fitted to a semitheoretical equation of McAllister. Excess viscosity,
volume and Gibbs energy of activation of flow have been evaluated, and the
departure from ideal behaviour is explained on the basis of specific
interactions between the components of this mixture.
Preparation and Structural Characterization of a Diaza 21-Crown-7 Ether Complex With Barium Picrate - (3,6,9,12,15-Pentaoxa-26,29-Diazatetracyclo[15.8.4.020,28.023,27]-Nonaco Sa-17,19,21,23,25(1),26,28-Heptaene-2,16-Dione)Barium(II) Picrate
Authors: Chandler CJ , Gable RW , Gulbis JM , Mackay MF
Published: May 2006

The synthesis,
characterization and crystal stucture of the title
complex is reported. The triclinic crystals belong to the space group Pī with a 12.726(5), b 14.284(5), c 11.094(5)Ǻ,
α 95.76(5),β 93.42(4), γ 88.66(5)� and Z 2. Refinement with 5365
diffractometer data measured with Cu Kα radiation converged at R 0.096. The barium ion is
coordinated by a diaza 21-crown-7 ether ligand , which incorporates a phenanthroline
moiety, and by two bidentate picrate
anions, and thus has 11-coordination. The Ba -O bonds
range from 2.62(1) to 3.02(1)Ǻ and the Ba -N
bonds have lengths of 3.00(1) and 3.05(1)Ǻ. Disorder is evident in the
aliphatic chain of the polyether and, apart from the orientation about a C-O
bond in the disordered segment of the chain, the angles about the C-O and C-C
bonds define gauche and anti conformations respectively.
Crystal-Structure of 0.53[Mer-(Pme2ph)3cl3iriii] 0.47[Mer-(Pme2ph)3- Trans-Cl2hiriii]
Authors: Robertson GB , Tucker PA
Published: May 2006

Evaporation of a methanol solution
containing both mer -(PMe2Ph)3Cl3IrIII
(1) and mer -(Pme2Ph)3H-trans-Cl2IrIII
(2) yields a new crystalline species (3) which is morphologically distinct from
either (1) or (2). The structure of (3) has been determined by single-crystal
X-ray diffraction analysis. Crystals are monoclinic, space group P21/c,
with a 15.747(2), b 10.305(1), c 16.790(2)Ǻ, β 92.75(3)� and Z 4, and
contain, in approximately equal amounts, discrete molecules of both (1) and (2)
distributed randomly in common lattice sites. Site content differs only according
to whether there is H or Cl trans to the unique phosphine ligand . Structure
refinement by full-matrix least-squares analysis (6183 reflections, 413
parameters) converged with R = 0.026, Rw = 0.034, and
site occupancy factor for the unique chlorine atom equal to 0.530(4). Molecules
each exhibit the conformation observed for pure (1) [pure (2) differs]. Derived
metal- ligand distances are very similar to the
weighted averages [53% (1), 47% (2)] of the corresponding distances in (1) and
(2).
An Improvement in the Preparation of Some Carbohydrate Benzylidene Acetals
Authors: Ferro V , Mocerino M , Stick RV , Tilbrook DMG
Published: May 2006

Carbohydrate benzylidene and p- methoxybenzylidene
acetals are easily prepared by treatment of various
sugar derivatives with either benzaldehyde diethyl acetal or p- methoxybenzaldehyde diethyl
acetal , respectively, in refluxing chloroform
containing camphorsulfonic acid.
The G12 family of heterotrimeric G proteins promotes breast cancer invasion and metastasis
Authors: Kelly Patrick , Moeller Benjamin J. , Juneja Juhi , Booden Michelle A. , Der Channing J. , Daaka Yehia , Dewhirst Mark W. , Fields Timothy A. , Casey Patrick J.
Published: May 2006

Although the prognosis for patients with early-stage breast cancer has improved, the therapeutic options for patients with locally advanced and metastatic disease are limited. To improve the treatment of these patients, the molecular mechanisms underlying breast cancer invasion and metastasis must be understood. In this study, we report that signaling through the G12 family of heterotrimeric G proteins (Gα12 and Gα13) promotes breast cancer cell invasion. Moreover, we demonstrate that inhibition of G12 signaling reduces the metastatic dissemination of breast cancer cells
in vivo
. Finally, we demonstrate that the expression of Gα12 is significantly up-regulated in the earliest stages of breast cancer, implying that amplification of G12 signaling may be an early event in breast cancer progression. Taken together, these observations identify the G12 family proteins as important regulators of breast cancer invasion and suggest that these proteins may be targeted to limit invasion- and metastasis-induced patient morbidity and mortality.
Experiments with lithium limiter on T-11M tokamak and applications of the lithium capillary-pore system in future fusion reactor devices
Authors: Mirnov S V , Azizov E A , Evtikhin V A , Lazarev V B , Lyublinski I E , Vertkov A V , Prokhorov D Yu
Published: May 2006

The paper is an overview of recent results of Li limiter testing in T-11M tokamak. The lithium limiter is based on the capillary-pore system (CPS) concept. The Li erosion process and deuterium (D2) and helium (He) sorption by Li first wall were investigated. The ability of capillary forces to confine the liquid Li in the CPS limiter during disruption was demonstrated. The idea of combined lithium limiter with thin (0.6 mm) CPS coating as a solution of the heat removal problem was realized. As a result the quasi steady-state tokamak regime with duration up to 0.3 s and clean (Zeff= 1) deuterium plasma has been achieved. The temporal evolution of the lithium surface temperature during discharge was measured by a IR radiometer and then was recalculated to the surface power load. For the estimation of the Li limiter erosion the Li neutral and ions spectral line emission were observed. The increase in lithium erosion as a result of limiter heating was discovered. The radial distribution of plasma column radiation measurements showed up to 90% of the total radiation losses in a relatively thin (5 cm) boundary layer and only 10% in a plasma centre during discharges with high Li influx. Oscillations of Li emission and saw-tooth-like oscillations of the limiter surface temperature have been detected in discharge regimes with highest Li limiter temperature (>600 °C). A version of Li CPS first wall of DEMO reactor and Li CPS limiter experiment in the International Thermonuclear Energy Reactor are suggested.
Combining multiple microarrays in the presence of controlling variables
Authors: Park Taesung , Yi Sung-Gon , Shin Young Kee , Lee SeungYeoun
Published: May 2006

Motivation: Microarray technology enables the monitoring of expression levels for thousands of genes simultaneously. When the magnitude of the experiment increases, it becomes common to use the same type of microarrays from different laboratories or hospitals. Thus, it is important to analyze microarray data together to derive a combined conclusion after accounting for the differences. One of the main objectives of the microarray experiment is to identify differentially expressed genes among the different experimental groups. The analysis of variance (ANOVA) model has been commonly used to detect differentially expressed genes after accounting for the sources of variation commonly observed in the microarray experiment.

Results: We extended the usual ANOVA model to account for an additional variability resulting from many confounding variables such as the effect of different hospitals. The proposed model is a two-stage ANOVA model. The first stage is the adjustment for the effects of no interests. The second stage is the detection of differentially expressed genes among the experimental groups using the residuals obtained from the first stage. Based on these residuals, we propose a permutation test to detect the differentially expressed genes. The proposed model is illustrated using the data from 133 microarrays collected at three different hospitals. The proposed approach is more flexible to use, and it is easier to accommodate the individual covariates in this model than using the meta-analysis approach.

Availability: A set of programs written in R will be electronically sent upon request.

Contact:  tspark@stats.snu.ac.kr
Distance-based clustering of CGH data
Authors: Liu Jun , Mohammed Jaaved , Carter James , Ranka Sanjay , Kahveci Tamer , Baudis Michael
Published: May 2006

Motivation: We consider the problem of clustering a population of Comparative Genomic Hybridization (CGH) data samples. The goal is to develop a systematic way of placing patients with similar CGH imbalance profiles into the same cluster. Our expectation is that patients with the same cancer types will generally belong to the same cluster as their underlying CGH profiles will be similar.

Results: We focus on distance-based clustering strategies. We do this in two steps. (1) Distances of all pairs of CGH samples are computed. (2) CGH samples are clustered based on this distance. We develop three pairwise distance/similarity measures, namely raw, cosine and sim. Raw measure disregards correlation between contiguous genomic intervals. It compares the aberrations in each genomic interval separately. The remaining measures assume that consecutive genomic intervals may be correlated. Cosine maps pairs of CGH samples into vectors in a high-dimensional space and measures the angle between them. Sim measures the number of independent common aberrations. We test our distance/similarity measures on three well known clustering algorithms, bottom-up, top-down and k-means with and without centroid shrinking. Our results show that sim consistently performs better than the remaining measures. This indicates that the correlation of neighboring genomic intervals should be considered in the structural analysis of CGH datasets. The combination of sim with top-down clustering emerged as the best approach.

Availability: All software developed in this article and all the datasets are available from the authors upon request.

Contact:  juliu@cise.ufl.edu
Protein classification using probabilistic chain graphs and the Gene Ontology structure
Authors: Carroll Steven , Pavlovic Vladimir
Published: May 2006

Motivation: Probabilistic graphical models have been developed in the past for the task of protein classification. In many cases, classifications obtained from the Gene Ontology have been used to validate these models. In this work we directly incorporate the structure of the Gene Ontology into the graphical representation for protein classification. We present a method in which each protein is represented by a replicate of the Gene Ontology structure, effectively modeling each protein in its own ‘annotation space’. Proteins are also connected to one another according to different measures of functional similarity, after which belief propagation is run to make predictions at all ontology terms.

Results: The proposed method was evaluated on a set of 4879 proteins from the Saccharomyces Genome Database whose interactions were also recorded in the GRID project. Results indicate that direct utilization of the Gene Ontology improves predictive ability, outperforming traditional models that do not take advantage of dependencies among functional terms. Average increase in accuracy (precision) of positive and negative term predictions of 27.8% (2.0%) over three different similarity measures and three subontologies was observed.

Availability: C/C++/Perl implementation is available from authors upon request.

Contact:  vladimir@cs.rutgers.edu