bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective Synthesis of O‐Methoxycarbonyl Cyanohydrins: Chiral Building Blocks Generated by Bifunctional Catalysis with BINOLAM‐AlCl
Authors: Baeza Alejandro , Casas Jesús , Nájera Carmen , Sansano José M. , Saá José M. 
Published: February 2006

Abstract(R)‐ or (S)‐BINOLAM‐AlCl, generated in situ, work as bifunctional catalysts in promoting the enantioselective cyanoalkoxycarbonylation of aldehydes. The reaction is wide in scope and the mechanistic evidence gathered suggests the intervention of an indirect process involving enantioselective hydrocyanation by HCN, followed by O‐alkoxycarbonylation. The resultant O‐alkoxycarbonyl cyanohydrins are shown to be important chiral building blocks for synthesis. Chemoselective hydrolysis can thus be directed either to provide enantioenriched β‐hydroxy esters, or acids, or instead to give O‐methoxycarbonyl β‐hydroxy acids, esters, or amides. In addition, the enantiopure cyanocarbonates can be converted into β‐amino alcohols by reduction with lithiumaluminium hydride. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Beyond TPPTS: New Approaches to the Development of Efficient Palladium‐Catalyzed Aqueous‐Phase Cross‐Coupling Reactions
Authors: Shaughnessy Kevin H. 
Published: February 2006

AbstractWater is an attractive solvent for metal‐catalyzed reactions with both economic and environmental sustainability benefits. In addition, the use of a hydrophilic catalyst in an aqueous‐biphasic solvent system provides the opportunity to easily recover, and potentially recycle, the catalyst species. The feasibility of cross‐coupling reactions catalyzed by hydrophilic palladium catalysts was first demonstrated using sulfonated analogs of triphenylphosphane, such as tris(3‐sulfonatophenyl)phosphane trisodium salt (TPPTS). Catalysts derived from TPPTS and other structurally similar hydrophilic phosphanes are generally effective only with aryl iodides and activated aryl bromides. This microreview will focus on more recently developed hydrophilic ligands with increased steric demand and electron‐donating abilities that are effective in coupling reactions of aryl bromides and chlorides under mild conditions in aqueous solvents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Amperometric Hydrogen Peroxide Biosensor Based on the Immobilization of Horseradish Peroxidase (HRP) on the Layer‐by‐Layer Assembly Films of Gold Colloidal Nanoparticles and Toluidine Blue
Authors: Chen Shihong , Yuan Ruo , Chai Yaqin , Xu Lan , Wang Na , Li Xuenian , Zhang Lingyan 
Published: February 2006

AbstractThe precursor film was first formed on the Au electrode surface based on the self‐assembly of L‐cysteine and the adsorption of gold colloidal nanoparticles (nano‐Au). Layer‐by‐layer (LBL) assembly films of toluidine blue (TB) and nano‐Au were fabricated by alternately immersing the electrode with precursor film into the solution of toluidine blue and gold colloid. Cyclic voltammetry (CV) and quartz crystal microbalance (QCM) were adopted to monitor the regular growth of {TB/Au} bilayer films. The successful assembly of {TB/Au}n films brings a new strategy for electrochemical devices to construct layer‐by‐layer assembly films of nanomaterials and low molecular weight materials. In this article, {TB/Au}n films were used as model films to fabricate a mediated H2O2 biosensor based on horseradish peroxidase, which responded rapidly to H2O2 in the linear range from 1.5×10−7 mol/L to 8.6×10−3 mol/L with a detection limit of 7.0×10−8 mol/L. Morphologies of the final assembly films were characterized with scanning probe microscopy (SPM).
Cadmium Complexation in Culture Media
Authors: Ceretti Helena M. , Vullo Diana L. , Zalts Anita , Ramírez Silvana A. 
Published: February 2006

AbstractSquare‐wave anodic stripping voltammetry (SW‐ASV) has been applied to monitor changes in the complexing capacity (CC) in a microbiological culture medium through different physiological states, focusing on cadmium interactions with the potential ligands. Total ligand concentration (Lt) is evaluated both from the titration curve and Ruzic linearization, with good agreement between the methods. Values obtained for the conditional stability constant suggest the occurrence of moderate ligands. Results show that the studied culture medium is capable of complexing cadmium and that the complexing capacity is affected by the physiological states of bacteria.
Highly Sensitive and Selective Measurement of Bismuth in Seawater and Drug with 1,2‐Phenylenedioxydiacetic Acid by Cathodic Adsorptive Stripping Voltammetry
Authors: Gholivand M. B. , Romiani A. A. 
Published: February 2006

AbstractA new method is presented for determination of bismuth based on cathodic adsorptive stripping of complex bismuth with 1,2‐phenylenedioxydiacetic acid (PDA) at a hanging mercury drop electrode (HMDE). The effect of various parameters such as pH, concentration of ligand, accumulation potential and accumulation time on the selectivity and sensitivity were studied. The optimum conditions for determination of bismuth include nitric acid concentration 0.01 M, 8.0×10−4 M PDA and accumulation time 120 s, accumulation potential of −200 mV. The limits of detection are 0.25 and 0.05 nM, and responses are linear 1–1000 and 0.1–400 nM at tacc of 60 and 120 s, respectively. Many common anions and cations do not interfere in the determination of bismuth. The method was applied to the determination of bismuth in some real samples such as sea – and spring water and drug.
Simulations demonstrating interaction between coarse and fine sediment loads in rain‐impacted flow
Authors: Kinnell P. I. A. 
Published: February 2006

AbstractRain‐impacted flows dominate sheet and interrill erosion and are important in eroding soil rich in nutrients and other chemicals which may have deleterious effects on water quality. Erosion in rain‐impacted flow is associated with raindrop detachment followed by transport either by the combination of flow velocity and raindrop impact (raindrop‐induced flow transport, RIFT) or the inherent capacity of the flow to transport detached material. Coarse particles tend to be transported by RIFT, while fine particles tend to be transported without any assistance from raindrop impact. Because the transport process associated with coarse particles is not 100 per cent efficient, it generates a layer of loose particles on the soil surface and this layer protects the underlying soil from detachment. Simulations were performed by modelling the uplift and downstream movement of both fine and coarse particles detached from the soil surface by individual raindrop impacts starting with a surface where no loose material was present. The simulations produced a flush of fine material followed by a decline in the discharge of fine material as the amount of loose material built up on the bed. The decline in the discharge of fine material was accompanied by an increase in the discharge of coarse material. The relative amounts of coarse and fine material discharged in the flow varied with flow velocity and cohesion in the surface of the soil matrix. The results indicate that the discharge of various sized sediments is highly dependent on local soil, rain and flow conditions and that extrapolating the results from one situation to another may not be appropriate. Copyright © 2006 John Wiley & Sons, Ltd.
Chemical composition of essential oils of two submerged macrophytes, Ceratophyllum demersum L. and Vallisneria spiralis L.
Authors: Qiming Xian , Haidong Chen , Huixian Zou , Daqiang Yin 
Published: February 2006

AbstractThe essential oils from leaves of Ceratophyllum demersum L. and Vallisneria spiralis L. from China were isolated by steam distillation in yields of 0.15% and 0.10%, respectively, and their chemical composition was examined by GC and GC–MS. More than 50 constituents were identified, representing 87% of the total oils. The main components were basically the same in the two plants' essential oils. 2‐Methylpropanoic acid 3‐hydroxy‐2,4,4‐trimethylpentyl ester (>15%), 2‐methylpropanoic acid 2,2‐dimethyl‐1‐(2‐hydroxy‐1‐methylethyl)propyl ester (>3%), β‐ionone‐5,6‐epoxide (>7%), toluene (>6%), hexanal (>5%) and 1,2‐benzenedicarboxylic acid di(2‐methylpropyl) ester (>5%) were the major components. Copyright © 2006 John Wiley & Sons, Ltd.
Novel synthesis of flavour quality γ‐lactones
Authors: Zope Dhananjay D. , Patnekar Shridhar G. , Kanetkar Vinod R. 
Published: February 2006

AbstractThe cyclization of 3‐alkenoic acids with 80% sulphuric acid in the synthesis of γ‐lactones is always associated with fumes of sulphur dioxide gas and traces of cyclopentenones. The cyclopentenones formed during the reaction give off‐odours to the γ‐lactones formed. Two catalysts, p‐toluene sulphonic acid and o‐phosphoric acid, with a catalytic amount of perchloric acid, were tried in the lactonization reaction to obtain γ‐lactones in high yields, and the reaction was free from sulphur dioxide gas fumes and cyclopentenones. A comparison of these catalysts with 80% sulphuric acid in the synthesis of γ‐lactones was also made. Copyright © 2006 John Wiley & Sons, Ltd.
Asterella africana (Mont.) A. Evans grown on Madeira and in mainland Portugal: morphological data and composition of the essential oil
Authors: Figueiredo A. Cristina , Barroso José G. , Pedro Luis G. , Fontinha Susana S. , Sim‐Sim Manuela , Sérgio Cecília , Luis Leena , Scheffer Johannes J. C. 
Published: February 2006

AbstractAsterella africana (Mont.) A. Evans was collected on Madeira and in mainland Portugal at distinct locations and collection dates. The morphology of this marchantioid liverwort was analysed by scanning electron microscopy. The Madeiran A. africana showed a large variability in spore and elater dimensions, but marked differences have not been found in most of the morphological characters. Essential oil samples isolated by distillation‐extraction were analysed by GC and GC–MS. These samples were dominated by the monoterpene fraction (79–84%); the sesquiterpene and non‐terpenoid fractions amounted to 1–2% and 4–8%, respectively. Myrtenyl acetate (30–42%) and α‐pinene (10–17%) were the dominant components of all A. africana oil samples; the percentage contents of the other main components differed. Copyright © 2006 John Wiley & Sons, Ltd.
The essential oil composition of Hypericum scabrum L. from Iran
Authors: Morteza‐Semnani Katayoun , Saeedi Madjid , Changizi Shayesteh 
Published: February 2006

AbstractThe composition of the essential oil obtained from the dried flowering aerial parts of Hypericum scabrum L. (Hypericaceae) was analysed by GC and GC–MS. Eighty‐five components were identified in this oil. The major constituents of the essential oil were α‐pinene (45.3%), n‐nonane (5.6%) and thymol (5.3%). The essential oil of the flowering aerial parts of H. scabrum was rich in monoterpenoids. Copyright © 2006 John Wiley & Sons, Ltd.
Headspace analysis of the volatile constituents from Juniperus communis L. ‘berries’ (cones) grown wild in Greece
Authors: Chatzopoulou P. S. , Katsiotis S. T. 
Published: February 2006

AbstractThe fraction of highly volatile compounds is quite important to define the first sensory impact of an aromatic smell, and one of the most accurate ways to examine it is almost always by the headspace technique. A panel of 20 characteristic aromatic constituents, also shown to be the main constituents, has been studied in relation to juniper aroma. The results from the static headspace–GC (SH–GC) technique applied for the extraction and analysis of the volatile components from Juniperus communis L. berries (cones) showed that: (a) the monoterpene hydrocarbons formed the main group of constituents (73.5–93.7%); (b) temperatures and extraction times were significant factors, influencing the amounts of all the groups of volatiles; and (c) comminution of the plant material influenced the headspace procedure differently. Remarkable differences were observed, particularly between the quantitative synthesis of the distillate and the headspace extract. Copyright © 2006 John Wiley & Sons, Ltd.
Composition and antimicrobial activity of the essential oil of Pluchea arabica from Oman
Authors: Suliman Fakhr Eldin O. , Fatope Majekodunmi O. , Al‐Saidi Salim H. , Al‐Kindy Salma M. Z. , Marwah Ruchi G. 
Published: February 2006

AbstractFresh twigs of Pluchea arabica (Boiss) Qaiser & Lack (Compositae) were steam‐distilled and the essential oil obtained was analysed by GC–MS. Forty‐four components were identified, accounting for 93.2% of the total components detected. The major constituents were δ‐cadinol (26.8%), 9‐(1‐methylethylidene)‐bicyclo[6.1.0]nonane (10.8%), caryophyllene oxide (10.0%), methyleugenol (9.2%) and β‐caryophyllene (6.9%). The essential oil of P. arabica was active against Staphylococcus aureus (ATCC 29213), Candida albicans (ATCC 10231) and Bacillus subtilis when tested against seven organisms. The oil was found to be less fragrant than Ocimum forskaoli oil in an odour test. Copyright © 2006 John Wiley & Sons, Ltd.
Composition of the essential oil of Centaurea huber‐morathii Wagenitz isolated from seeds by microdistillation
Authors: Başer K. Hüsnü Can , Özek Gülmira , Özek Temel , Duran Ahmet 
Published: February 2006

AbstractThe volatile constituents of the seeds of Centaurea huber‐morathii Wagenitz (Asteraceae), obtained by microdistillation, were analysed by GC and GC–MS. Eighty‐five constituents were identified in the oil, with octanol (17.8%), hexadecanoic acid (8.0%), p‐cymene (4.9%) and caryophyllene oxide (3.3%) as the major components. Copyright © 2006 John Wiley & Sons, Ltd.
Volatile constituents from headspace and aqueous solution of genipap (Genipa americana) fruit isolated by the solid‐phase extraction method
Authors: Pinto Alice B. , Guedes Clarissa M. , Moreira Ricardo F. A. , Maria Carlos A. B. De 
Published: February 2006

AbstractVolatiles of genipap fruit were isolated by both headspace and liquid‐phase adsorptive chromatography and analysed by means of gas chromatography–flame ionization detection (GC–FID), GC–mass spectrometry (GC–MS) and GC–olfactometry (GC–O)/aroma extract dilution analysis (AEDA). A total of 52 volatiles were identified; among these, 32 were reported as genipap constituents for the first time. Thirty‐seven volatiles were positively identified in genipap fruit aroma. Low‐boiling esters predominated in the headspace fraction. Based on GC–O/AEDA, hexanoic, 2‐ and 3‐methylbutanoic acids and the corresponding methylbutanoic esters were the most potent odorants in both fractions. Thus they might be related to the first odour impression of the fruit. Odorants with lower odour potencies, such as methyl hexanoate, methyl and ethyl octanoate and acetic and 2‐methylpropanoic acids could have some additional effect on the fruit aroma. Vanillin, which was identified for the first time in this fruit, might also contribute to the overall genipap flavour. Copyright © 2006 John Wiley & Sons, Ltd.
Comparative study on the antimicrobial activities of different sandalwood essential oils of various origin
Authors: Jirovetz Leopold , Buchbauer Gerhard , Denkova Zapriana , Stoyanova Albena , Murgov Ivan , Gearon Valerie , Birkbeck Steve , Schmidt Erich , Geissler Margit 
Published: February 2006

AbstractIn total, eight samples of different sandalwoods [Amyris balsamifera L., Santalum album L. and Santalum spicatum (R.Br.) A.DC.] and a mixture of α‐ and β‐santalols, as well as eugenol as reference compound, were tested by an agar dilution and agar diffusion method for their antimicrobial activities against the yeast Candida albicans, the Gram‐positive bacterium Staphylococcus aureus and the Gram‐negative bacteria Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The main compounds of each essential oil were investigated by gas chromatographic–spectroscopic (GC‐FID and GC–MS) and –olfactory methods to obtain information about the inßuence of these volatiles on the observed antimicrobial effects. For the santalol mixture, as well as for one S. album and one S. spicatum sample with moderate concentrations of santalols, antimicrobial activity was found against all the strains used. The A. balsamifera sample, containing only a small quantity of α‐santalol and nearly no β‐santalol, showed high effects only against Klebsiella pneumoniae, while against the other strains weak or no activity was observed. Therefore, santalols in medium and/or high concentrations in sandalwood oils show a significant inßuence on antimicrobial potential in such natural products. Copyright © 2006 John Wiley & Sons, Ltd.
Essential oil composition of four Plinia species (Myrtaceae)
Authors: Apel Miriam A. , Sobral Marcos , Zuanazzi José ångelo , Henriques Amélia T. 
Published: February 2006

AbstractThe essential oils obtained by steam distillation from fresh leaves of four Plinia species were analysed by GC–FID and GC–MS. Fifty‐two compounds were identified, accounting for 83.9–98.0% of the total oil. The four Plinia species were characterized by the dominance of sesquiterpenes, especially oxygenated sesquiterpenes. For P. edulis, β‐caryophyllene and its oxide, caryophyllene oxide, were present in high percentage (39.3%), followed by spathulenol (11.9%). P. trunciflora oil showed β‐caryophyllene (8.2%), bicyclogermacrene (10.6%), globulol (10.8%) and γ‐muurolene (9.2%) as the main components. The oil of P. cauliflora was dominated by spathulenol (27.2%), caryophyllene oxide (21.6%) and epi‐globulol (8.1%) and that of P. cordifolia was especially characterized by compounds with a bisabolane nucleus, such as α‐bisabolol oxide A (28.0%), α‐bisabolol oxide B (7.0%) and α‐bisabolol (5.8%). This last species also showed a high percentage of β‐caryophyllene (15.9%). Copyright © 2006 John Wiley & Sons, Ltd.
Volatile constituents of benzoin gums: Siam and Sumatra, part 3. Fast characterization with an electronic nose
Authors: Fernandez Xavier , Castel Cécilia , Lizzani‐Cuvelier Louisette , Delbecque Claire , Venzal Sophie Puech 
Published: February 2006

AbstractThe quality control of natural raw materials is a challenging issue for the food, cosmetic, perfume and tobacco industries. The applicability of an electronic nose for the discrimination of origin, qualities and harvesting year of a natural raw material (benzoin gum) currently used by all those industries was tested. An electronic nose including 18 metal oxide sensors was used to analyse and discriminate 56 benzoin gum samples according to their origin (Siam and Sumatra), quality grade, variety (mixture of gums traded as benzoin gums) and year of harvesting. Thanks to its sensitivity, the electronic nose based on metal oxide sensors demonstrated a high ability to assess both the quality and the organoleptic features of the benzoin gum samples. Fast analysis and ease of use make this instrument a good quality control tool. A comparison with an electronic nose based on fingerprint mass spectrometry was also studied. Copyright © 2006 John Wiley & Sons, Ltd.
Composition of a Pyrolytic oil from Cupressus funebris Endl. of Vietnamese origin
Authors: Duquesnoy Emilie , Dinh Nguyen Huu , Castola Vincent , Casanova Joseph 
Published: February 2006

AbstractA sample of pyrolytic oil of Vietnamese origin, extracted from Cupressus funbris Endl. was investigated by GC‐RI, GC‐MS and 13C‐NMR spectroscopy. In the pyrolytic oil, dominated by sesquiterpenes (76% of the total composition), 46 components were identified after repeated silica gel chromatography. The main components were: α‐cedrene (26.7%), cedrol (12.3%) and β‐cedrene (6.6%). The pyrolytic oil differed from the commercial Chinese cedarwood oil (C. funebris wood oil), on the one hand by the absence of thujopsene and conversely the presence of several bicyclo[4.4.0]decane hydrocarbons and alcohols (selinane and cadinane derivatives), and on the other hand by the presence, as minor components, of phenol derivatives. The composition of the pyrolytic oil was compared with that of a commercial sample of cerdarwood oil [53 components identified, thujopsene (25.9%), α‐cedrene (24.1%), cedrol (11.3%) and β‐cedrene (7.4%)]. Copyright © 2006 John Wiley & Sons, Ltd.
Simulation of shallow flows over variable topographies using unstructured grids
Authors: Mohammadian A. , Le Roux D. Y. 
Published: February 2006

AbstractSimulation of shallow flows over variable topographies is a challenging case for most available shock‐capturing schemes. This problem arises because the source terms and flux gradients are not balanced in the numerical computations. Treatments for this problem generally work well on structured grids, but they are usually too expensive, and most of them are not directly applicable to unstructured grids. In this paper we propose two efficient methods to treat the source terms without upwinding and to satisfy the compatibility condition on unstructured grids. In the first method, the calculation of the bed slope source term is performed by employing a compatible approximation of water depth at the cell interfaces. In the second one, different components of the bed slope term are considered separately and a compatible discretization of the components is proposed. The present treatments are applicable for most schemes including the Roe's method without changing the performance of the original scheme for smooth topographies. Copyright © 2006 John Wiley & Sons, Ltd.
Discretization and parallel performance of an unstructured finite volume Navier–Stokes solver
Authors: Mohsen Karimian S. A. , Straatman Anthony G. 
Published: February 2006

AbstractThe discretization, parallelization and performance of an implicit, unstructured, time‐dependent Computational Fluid Dynamics code is described. A detailed description is provided of the improvements made on second‐order accurate tools for spatial interpolation and gradient calculation to discretize the Navier–Stokes equations in an unstructured framework. The main goal in the development of the discretization tools was to ensure a scalable and accurate parallel code. The performance of the discretization tools has been validated using standard bench‐mark problems for non‐uniform, non‐orthogonal grids. Parallelization of the code is done within the PETSc framework using a single‐program‐multiple‐data (SPMD) parallelization model. The resulting parallel code is shown to scale linearly within the limit of the available number of processors. Copyright © 2006 John Wiley & Sons, Ltd.
Leg length, cognitive impairment and cognitive decline in an African‐Caribbean population
Authors: Mak Zanete , Kim Jae‐Min , Stewart Robert 
Published: February 2006

AbstractBackgroundShorter leg length is associated with an adverse environment in early childhood and has been found to be associated with a variety of disorders occurring in mid‐ to late‐life, including dementia in a Korean population. In a community population of African‐Caribbean elders, in whom leg length had been measured, we sought to compare associations with cognitive impairment at baseline and cognitive decline over a three‐year follow‐up period.MethodsOf 290 African‐Caribbean residents in south London recruited at baseline, 216 (74%) were re‐interviewed after a three‐year period and 203 had sufficient data for this analysis. Cognitive impairment was derived as a binary category from a battery of cognitive tests administered at baseline and cognitive decline was derived from change in performance on a subset of these tests. Leg length (iliac crest to lateral malleolus) was also measured.ResultsShorter leg length was associated with female sex, lower occupational social class and reported hypertension and diabetes. Shorter leg length (lowest quartile) was significantly associated with cognitive impairment but there were no apparent associations with cognitive decline. The association with cognitive impairment was independent of age, sex and education. Social class appeared to be an important mediating factor.ConclusionsShorter leg length may be a marker of early life stressors which result in reduced cognitive reserve. Interestingly this association was mediated more strongly by social class (previous occupational status) than by education in this population. Copyright © 2006 John Wiley & Sons, Ltd.