bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Electrical Properties of the Pr0.5+x−yBiyLi0.5−3xTiO3 System
Authors: Martínez‐Sarrión María‐Luisa , Mestres Lourdes , Herráiz Marta , Maqueda Oscar , Fernández Nestor , García Mario‐Fidel 
Published: June 2003

AbstractThe stoichiometry, polymorphism, and electrical behaviour of the solid solutions Pr0.5+x−yBiyLi0.5−3xTiO3 with perovskite‐like structure have been studied. Data are given as a solid solution triangle, XRD patterns for two polymorphs T and O, the composition dependence of their parameters, and ionic conductivity plots. A region of perovskite‐like solid solutions was obtained when the bismuth content in the general formula Pr0.5+x−yBiyLi0.5−3xTiO3 was y ⩽ 0.10 and the lithium content was 0.033 ⩽ x ⩽ 0.133. The compounds are mixed conductors. With increasing amounts of lithium the ionic conductivity first increased, reached a maximum for x = 0.20, with a conductivity at 25 °C of 6.639·10−3 S·cm−1, and then decreased. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Iron Complexes Containing the Ligand N,N′‐Bis(6‐methyl‐2‐pyridylmethyl)‐N,N′‐bis(2‐pyridylmethyl)ethane‐1,2‐diamine: Structural, Spectroscopic, and Electrochemical Studies, Reactivity with Hydrogen Peroxide and the Formation of a Low‐Spin Fe−OOH Complex
Authors: Balland Véronique , Banse Frédéric , Anxolabéhère‐Mallart Elodie , Nierlich Martine , Girerd Jean‐Jacques 
Published: June 2003

AbstractThe ligand N,N′‐bis(6‐methyl‐2‐pyridylmethyl)‐N,N′‐bis(2‐pyridylmethyl)ethane‐1,2‐diamine (L622M) has allowed to prepare the new FeII complex [(L622M)FeCl2] (1), and to compare its structural and spectroscopic characteristics with [(L622M)FeCl]PF6 (2). The molecular structure of 1, resolved by X‐ray diffraction, exhibits the ligand tetracoordinated with the two non‐methylated pyridine rings coordinated. As shown by UV/Vis spectroscopy and cyclic voltammetry, upon dissolution in methanol or acetonitrile, one chloride ion is released and replaced by a pyridine group. Therefore, complexes 1 and 2 adopt identical structures in solution, i.e. [(L622M)FeCl+. However, upon oxidation complex 1 gives several ferric complexes with the ligand L622M pentacoordinated, or tetracoordinated with two chloride ions. This peculiar behaviour is due to the presence of chloride ions in solution in the case of 1. Upon reaction with H2O2 in methanol, complex 2 leads to the formation of low‐spin [(L622M)FeIII(OOH)2+, whereas it is not observed in the case of 1. Based on the presence or not of chloride ions in solution, a mechanism is proposed for the reactivity of complexes 1 and 2 toward H2O2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Neutral and Cationic [Bis(η1‐amidosilyl)‐η5‐cyclopentadienyl]titanium and ‐zirconium Complexes: Synthesis, X‐ray Molecular Structures and DFT Calculations
Authors: Cano Jesús , Royo Pascual , Jacobsen Heiko , Blacque Olivier , Berke Heinz , Herdtweck Eberhardt 
Published: June 2003

AbstractTreatment of LiNHtBu with THF solutions of C5H4(SiMe2Cl)2gave C5H4(SiMe2NHtBu)2(1). Deprotonation of1with M(NMe2)4(M = Ti, Zr) under different conditions provided the monocyclopentadienyl complexes [M{η5‐C5H3[SiMe2(NHtBu)]2}(NMe2)3] [M = Ti (2), Zr (3)] and the single (η‐amidosilyl)cyclopentadienyl compounds [M{η5‐C5H3[SiMe2(NHtBu)][SiMe2(η1‐NtBu)]}(NMe2)2] [M = Ti (4), Zr (5)]. The related dibenzyl compounds [M{η5‐C5H3[SiMe2(NHtBu)][SiMe2(η1‐NtBu)]}(CH2Ph)2] [M = Ti (6), Zr (7)] resulted from treatment of1with M(CH2C6H5)4(M = Ti, Zr). Further deprotonation of the amido complexes4and5and the benzyl complexes6and7by heating in toluene solution gave the bis(η‐amidosilyl)cyclopentadienyl complexes [M{η5‐C5H3[SiMe2(η1‐NtBu)]2}(NMe2)] [M = Ti (8), Zr (9)] and [M{η5‐C5H3[SiMe2(η1‐NtBu)]2}(CH2Ph)] [M = Ti (10), Zr (11)], respectively. Treatment of the monobenzyl complexes10and11with B(C6F5)3yielded the cationic compounds [M{η5‐C5H3[SiMe2(η1‐NtBu)]2}]+as [(CH2Ph)B(C6F5)3]−[M = Ti (12), Zr (13)] salts. All new compounds were characterized by NMR spectroscopy, and the crystal structures of10and13were studied by diffraction methods. DFT calculations for the neutral and cationic species are described and provide an explanation for the unusual η1coordination of a phenyl ring to a group‐4 metal cation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Assembly of Dicobalt(III) Complexes Incorporating Di‐μ‐thiophenolate Moieties
Authors: Marin‐Becerra Armando , Stenson Philip A. , McMaster Jonathan , Blake Alexander J. , Wilson Claire , Schröder Martin 
Published: June 2003

AbstractThe dinuclear [CoIIICoIII] complexes [Co2(L1)(μ‐OAc)(OAc)(NH3)](PF6)2 and [(Co2(L2)2(μ‐OAc)](PF6), incorporating the rare Co(μ‐SR)2Co moiety associated with Schiff‐base co‐ligands, are protected by bridging μ‐OAc− units situated within a domed cavity formed by the complexes; increasing the steric bulk of the ligand, as in [L3]2−, affords the mononuclear species [Co(L3)(OAc)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, X‐ray Crystallographic and 1H NMR Spectroscopic Structural Studies on Cobalt(II) Complexes of Homoscorpionate, Heteroscorpionates and Chiral Tris(pyrazolyl)borates Obtained from 5(3)‐Isopropyl‐3(5)‐phenylpyrazole and 3,5‐Dimethylpyrazole
Authors: Ruman Tomasz , Ciunik Zbigniew , Wołowiec Stanislaw 
Published: June 2003

AbstractCondensation of 5(3)‐isopropyl‐3(5)‐phenylpyrazole with sodium borohydride led to a mixture of tris(pyrazolyl)borate ligands (Tpx) − the homoscorpionate hydrotris(5‐isopropyl‐3‐phenylpyrazolyl)borate and the heteroscorpionates hydro(3‐isopropyl‐5‐phenylpyrazolyl)bis(5‐isopropyl‐3‐phenylpyrazolyl)borate and hydrobis(3‐isopropyl‐5‐phenylpyrazolyl)(5‐isopropyl‐3‐phenylpyrazolyl)borate − that were converted into TpxCo(NCS) complexes. The molecular structures of pentacoordinate[hydrotris(5‐isopropyl‐3‐phenylpyrazolyl)borato](tetrahydrofuran)(thiocyanato)cobalt(II) (1‐THF) and [hydrobis(3‐isopropyl‐5‐phenylpyrazolyl)(5‐isopropyl‐3‐cobalt(II) (3‐THF) were elucidated crystallographically. Hydro(3,5‐dimethylpyrazolyl)bis(5‐isopropyl‐3‐phenylpyrazolyl)borate was also obtained by condensation of 2.1 equiv. of 5(3)‐isopropyl‐3(5)‐phenylpyrazole and 0.9 equiv. of 3,5‐dimethylpyrazole with sodium borohydride, and it was converted into [hydro(3,5‐dimethylpyrazolyl)bis(5‐isopropyl‐3‐phenylpyrazolyl)borato](thiocyanato)cobalt(II) (4), which was characterized by X‐ray crystallography. The latter was converted thermally under mild conditions (358 K in toluene) into [hydro(3,5‐dimethylpyrazolyl)(3‐isopropyl‐5‐phenylpyrazolyl)(5‐isopropyl‐3‐phenylpyrazolyl)borato](thiocyanato)cobalt(II) (9) in 45% yield, as was concluded from the 1H NMR spectrum of the post‐reaction mixture. The dimer of 9 was obtained as single crystals from toluene/hexane and its structure was determined crystallographically. Two chiral Tpx ligands of opposite boron‐centered configurations are coordinated to cobalt(II) ions in a κ3 fashion. The pentacoordinate metal ions are bridged head‐to‐tail by the thiocyanate anions. This chiral Tpx ligand is the first example of a borate with fixed boron‐centered chirality. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Reactivity of Primary and Secondary Amines, Secondary Phosphanes and N‐Heterocyclic Carbenes towards Group‐13 Metal(I) Halides
Authors: Baker Robert J. , Bettentrup Helga , Jones Cameron 
Published: June 2003

AbstractThe reactions of a variety of primary and secondary amines and secondary phosphanes with “GaI” have been examined. In all cases disproportionation reactions occurred which led to the gallium(II) iodide complexes [Ga2I4(L)2] [L = NCyH2, NtBuH2, NCy2H, PCy2H or PtBu2H (Cy = cyclohexyl)]. All complexes have been crystallographically characterised and have been shown to be dimers possessing Ga−Ga bonds. The reaction of the sterically hindered N‐heterocyclic carbene IPr [:CN(Ar)C2H2N(Ar) (Ar = C6H3iPr2‐2,6)] with “GaI” was also carried out and the novel salt [Ga2I5(IPr)][IPrH] was formed in good yield and crystallographically characterised. Finally, the related reaction of the less hindered cyclic carbene IMe [:CN(Me)C2Me2N(Me)] with InCl gave a low yield of the crystallographically characterised salt [{InCl(IMe)}2(μ‐Cl)(μ‐O)][Cl] which presumably forms due to the presence of adventitious oxygen in the reaction mixture. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New Bis(mercaptoimidazolyl)(pyrazolyl)borate Ligands and Their Zinc Complex Chemistry
Authors: Shu Mouhai , Walz Rainer , Wu Biao , Seebacher Jan , Vahrenkamp Heinrich 
Published: June 2003

AbstractNine new tripodal NS2 ligands of the bis(mercaptoimidazolyl)(pyrazolyl)borate type with varying 3‐R‐mercaptoimidazolyl moieties were prepared as their potassium salts. Treatment with zinc salts yielded the complex types L·Zn−Cl, L·Zn−I, L·Zn−ONO2, L·Zn−OClO3 and [L·Zn(imidazole)]ClO4. Attempts at the formation of L·Zn−OH or cationic L·Zn complexes resulted in dismutation and formation of ZnL2 complexes. Hydrolytic destruction yielded one [OZn4(thiooimidazolate)6] complex. The ZnS2NO coordination which is present in the enzyme‐substrate complex of alcohol dehydrogenase could be successfully modelled by an [L·Zn(C2H5OH)]+ complex. The L·Zn−X complexes showed very low catalytic activity in the dehydrogenation of 2‐propanol or the hydrogenation of p‐nitrobenzaldehyde. The new compounds were identified by a total of 12 structure determinations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The First One‐Dimensional Molecular Material Featuring Maleonitriledithiolate as a Subunit Exhibiting Metamagnetic‐Like Behavior
Authors: Xie Jingli , Ren Xiaoming , Gao Song , Zhang Wenwei , Li Yizhi , Lu Changsheng , Ni Chunlin , Liu Wenlong , Meng Qingjin , Yao Yuangen 
Published: June 2003

AbstractAn ion‐pair complex [FBzPyNH2][Ni(mnt)2] {[FBzPyNH2]+ = [1‐(4′‐fluorobenzyl)‐4‐amino]pyridinium and mnt2− = maleonitriledithiolate} has been obtained by I2 oxidation of the corresponding dianion complex. It forms a wellsegregated stacking column structure in the solid state, and exhibits antiferromagnetic ordering below 2.5 K. It is the first complex in this series of complexes containing a maleonitriledithiolate dianion that exhibits metamagnetism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Toolbox for exchanging constituent fatty acids in lecithins
Authors: Doig Steven D. , Diks Rob M. M. 
Published: June 2003

AbstractSince the compositional variety of phospholipids in native lecithins is limited, and structurally diverse synthetic phospholipids are expensive, the aim of this work was to develop a lecithin modification toolbox capable of modifying the fatty acid composition of native lecithins at a convenient lab‐scale of 10‐100 g. Starting with the native phospholipids of soybean lecithin, two types of fatty acid modification were carried out using either phospholipase A2 from porcine pancreas or a lipase from Rhizopus oryzae. The former was immobilised onto celite and used to selectively hydrolyse the sn‐2 positioned fatty acid and the latter, commercially available in an immobilised form, was used to transesterify novel fatty acids onto the sn‐1 position.The degree of phospholipid hydrolysis could be controlled between 5 and 95% by varying the contact time with the biocatalyst. A key parameter was the water concentration. By avoiding the presence of a bulk phase of water, emulsion formation was prevented and so simple product recovery was possible. However, sufficient water was required in order to maintain the water activity above 0.2, and because phospholipids increased the polarity of the solvent (hexane), it was necessary to add water in proportion to the lecithin concentration. During transesterification with methyllaurate, up to 43% lauric acid could be incorporated and although the recovery of fully acylated phospholipids was only 28%, due to the formation of hydrolysis products, they were isolated using solvent partitioning in hexane/isopropanol/water. The temperature was important in determining the relative rates of hydrolysis and transesterification and a lower temperature (40 °C) was favourable as the rate of hydrolysis was lowered without affecting the rate of transesterification.
Solid fat content in fats and oils ‐ determination by pulsed nuclear magnetic resonance spectroscopy [C‐IV 3g (2003)]
Authors: Fiebig Hans‐Jochen , Lüttke Jens 
Published: June 2003

AbstractThe “Joint Committee for the Analysis of Fats, Oils, Fatty products, Related Products and Raw Materials (GA FETT)” has developed the following method for the determination of the Solid Fat Content (SFC) in fats and oils. It is intended to include this method in Section C, Chapter IV of the German Standard Methods. The method reflexes the need of the fats and oils industry to get fast results and was tested in an interlaboratory test with 16 laboratories from 6 European countries.
Assessment and management of self‐harm in older adults attending accident and emergency: a comparative cross‐sectional study
Authors: Marriott Richard , Horrocks Judith , House Allan , Owens David 
Published: June 2003

AbstractObjectiveOlder people who undertake self‐harm are at higher suicide risk than are younger patients. This study examines whether this greater risk is reflected in the assessment and after‐care that older patients receive when they attend accident and emergency.MethodThis cross‐sectional study, set in the two accident and emergency departments in a large industrial city in Northern England, compared 141 consecutive attendances due to self‐harm among older patients (aged 55 years and over) with a random sample of 125 attendances of younger people (aged 15–54) attending because of self‐harm. Data were drawn from accident and emergency records and from psychiatric and general hospital casenotes.ResultsCompared with the younger group, older patients were significantly more likely to be admitted from accident and emergency to the general hospital, to receive a specialist assessment whilst at the hospital, and to be offered psychiatric after‐care—either as a psychiatric in‐patient or an out‐patient.ConclusionsFortunately, older people attending accident and emergency following self‐harm seemed likely to receive psychosocial assessment from a mental health specialist, and they were much more likely than younger patients to be offered after‐care. Hospitals will need to monitor accident and emergency and other records if they are to check that their services are responding to the high risks seen in older patients. Copyright © 2003 John Wiley & Sons, Ltd.
Prescription practices of diagnostic imaging in dementia: a survey of 47 Alzheimer's Centres in Northern Italy
Authors: Riello R. , Albini C. , Galluzzi S. , Pasqualetti P. , Frisoni G. B. 
Published: June 2003

AbstractBackgroundTo date, there are no data at the national or European level on the prescription practices of imaging (CT, MR, and SPET) in the diagnosis of cognitively impaired elderly patients.MethodsWe addressed prescription practices of diagnostic imaging in 47 Alzheimer's Centres in Northern Italy, with an ad‐hoc questionnaire.ResultsThe use of imaging in new cases was relatively intensive: 62% of the Alzheimer's Centres prescribed CT to more than 95% of cases, 24% prescribed MR to more than 33% of cases, and 33% prescribed SPET to more than 5% of cases. A minority of Alzheimer's Centres (n = 3, 6%) prescribed imaging to less than 100% of new cases. The association between onsite scanner availability and frequency of prescription increased from CT (Odds ratio (OR) = 1.8) through MR (OR = 2.4) to SPET (OR = 4.6), although only the latter was significant (95% confidence interval (CI) 1.2–17.7, p = 0.003). Patient‐related factors (age, severity of cognitive impairment, and clinical suspicion of cerebrovascular disease) influenced prescription of structural imaging in 30–53% of Alzheimer's Centres and organizational factors (onsite scanner availability, and waiting list) in a similar proportion (32 and 43% respectively).ConclusionsOrganizational factors play a relevant role in the prescription of imaging exams in patients with cognitive impairment and, at least for CT, the perceived diagnostic added value is rather low, suggesting a high degree of uncertainty in the clinical use of imaging techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Party loyalty as habit formation
Authors: Shachar Ron 
Published: June 2003

AbstractIn most democracies, at least two out of any three individuals vote for the same party in sequential elections. This paper presents a model in which vote‐persistence is partly due to the dependence of the utility on the previous voting decision. This dependence is termed ‘habit formation’. The model and its implications are supported by individual‐level panel data on the presidential elections in the USA in 1972 and 1976. For example, it is found that the voting probability is a function of the lagged choice variable, even when the endogeneity of the lagged variable is accounted for, and that the tendency to vote for different parties in sequential elections decreased with the age of the voter. Furthermore, using structural estimation the effect of habit is estimated, while allowing unobserved differences among respondents. The structural habit parameter implies that the effect of previous votes on the current decision is quite strong. The habit model fits the data better than the traditional ‘party identification’ model. Copyright © 2003 John Wiley & Sons, Ltd.
Lipase production in continuous culture of Candida rugosa
Authors: Montesinos JL , Dalmau E , Casas C 
Published: June 2003

AbstractThe yeast Candida rugosa produces multiple extracellular lipases. The production of extra‐ and intracellular lipases was investigated in continuous cultures using a sole or different mixtures of carbon sources. Also, the effect of different C:N ratios was tested. Lipase productivity in continuous cultures increased by 50% compared with data obtained from batch fermentations and depended on the dilution rate applied. Maximum yields relative to consumed substrate were obtained with oleic acid at low dilution rate. It was found that during nitrogen limitation, lipase activity was suppressed. All carbon source mixtures tested allowed both cell growth and lipase production, but extra‐ and intracellular lipase activities were affected by the combination of substrates used. Maximum extracellular lipolytic productivity was attained with lactic and oleic acid mixtures, probably due to the non‐repressor effect of these carbon sources. The chemical composition of the biomass also depended on the type of substrate used and was related to the accumulation of lipidic compounds as intracellular inclusions, which were observed when oleic acid was used as the carbon source. The results obtained were compared with previous data from batch and fed‐batch cultures in order to select the best process strategies for the lipase production with C rugosa. The best lipase yields were obtained in fed‐batch fermentations using oleic acid. Copyright © 2003 Society of Chemical Industry
An improved model of association for VH–VL immunoglobulin domains: Asymmetries between VH and VL in the packing of some interface residues
Authors: Vargas‐Madrazo Enrique , Paz‐García Enrique 
Published: June 2003

AbstractThe antibody‐binding site is formed as a result of the association between VH and VL domains. Several studies have shown that this association plays an important role in the mechanism of antigen–antibody interaction (Stanfield et al. Structure 1: 83–93, 1993). Considering this, we propose that variations in the VH–VL association are part of the diversification strategy of the antibody repertoires. Previously, a model of association for VH–VL domains based on geometrical characteristics of the packing at the interface was developed by Chothia et al. (J. Mol. Biol. 186: 61–663, 1985). This model includes a common association form for antibodies and a three‐layer structure for the interface. In the present work, a complementary model is introduced to account for the general geometrical restrictions of the VH–VL interface, and particular arrangements related to the chemical properties or the side‐chain orientations of participating residues. Groups of residues assume common side‐chain orientations, which are apparently related to particular functions of different interface zones. Analyses of amino acid usage and network are in agreement with the side‐chain orientation patterns. Based on these observations, a three‐zone model has evolved to illuminate geometrical and functional restrictions acting over the VH–VL interface. Additionally, this study has revealed the asymmetrical relationships between VH and VL residues important for the association of the two domains. Copyright © 2003 John Wiley & Sons, Ltd.
Soil biochemical and chemical changes in relation to mature spruce (Picea abies) forest conversion and regeneration
Authors: Zhong Zheke , Makeschin Franz 
Published: June 2003

AbstractTo investigate soil changes from forest conversion and regeneration, soil net N mineralization, potential nitrification, microbial biomass N, L‐asparaginase, L‐glutaminase, and other chemical and biological properties were examined in three adjacent stands: mature pure and dense Norway spruce (Picea abies (L.) Karst) (110 yr) (stand I), mature Norway spruce mixed with young beech (Fagus sylvatica) (5 yr) (stand II), and young Norway spruce (16 yr) (stand III). The latter two stands were converted or regenerated from the mature Norway spruce stand as former. The studied soils were characterized as having a very low pH value (2.9 – 3.5 in 0.01 M CaCl2), a high total N content (1.06 – 1.94 %), a high metabolic quotient (qCO2) (6.7 – 16.9 g CO2 kg–1 h–1), a low microbial biomass N (1.1 – 3.3 % of total N, except LOf1 at stand III), and a relatively high net N mineralization (175 – 1213 mg N kg–1 in LOf1 and Of2, 4 weeks incubation). In the converted forest (stand II), C : N ratio and qCO2 values in the LOf1 layer decreased significantly, and base saturation and exchangeable Ca showed a somewhat increment in mineral soil. In the regenerated forest (stand III), the total N storage in the surface layers decreased by 30 %. The surface organic layers (LOf1, Of2) possessed a very high net N mineralization (1.5 – 3 times higher than those in other two stands), high microbial biomass (C, N), and high basal respiration and qCO2 values. Meanwhile, in the Oh layer, the base saturation and the exchangeable Ca decreased. All studied substrates showed little net nitrification after the first period of incubation (2 weeks). In the later period of incubation (7 – 11 weeks), a considerable amount of NO3‐N accumulated (20 – 100 % of total cumulative mineral N) in the soils from the two pure spruce stands (I, III). In contrast, there was almost no net NO3‐N accumulation in the soils from the converted mixed stand (II) indicating that there was a difference in microorganisms in the two types of forest ecosystems. Soil microbial biomass N, mineral N, net N mineralization, L‐asparaginase, and L‐glutaminase were correlated and associated with forest management.