bluuebunny/crossref_metadata_2025 huggingface dataset:
Methyllead(IV) Derivatives Stabilized by DAPTSC2–: Synthesis and Structures of New Diorganolead(IV) Complexes
Authors: Casas José S. , Castellano Eduardo E. , Ellena Javier , García‐Tasende María S. , Namor Facundo , Sánchez Agustín , Sordo José , Vidarte María J.
Published: June 2007

The reaction of the bis(thiosemicarbazone) of dimethyl pyridine‐2,6‐diyl diketone, H2DAPTSC, with PbMe2(OAc)2, PbMePh(OAc)2 or PbPh2(OAc)2 in MeOH afforded the complexes [PbMe2(DAPTSC)], [PbMePh(DAPTSC)] or [PbPh2(DAPTSC)] (in the first two cases together with [Pb(DAPTSC)]). X‐ray crystallography of the Pb(IV) complexes showed that the metal has a pentagonal bipyramidal coordination sphere. The N3,S2‐bound DAPTSC2– anion occupied the equatorial plane and the organic groups were in the apical positions. These compounds retain the same coordination mode in DMSO solution. DAPTSC2– is also N3,S2‐bound in [Pb(DAPTSC)], a complex with a stereochemically active PbII lone pair. The reaction of PbPh2Cl2 with H2DAPTSC, also in methanol at room temperature, afforded [PbPh2(H2DAPTSC)]2[PbPh2Cl4]Cl2·6CH3OH. X‐ray crystallography of this centrosymmetric complex showed it to consist of two [PbPh2(H2DAPTSC)]2+ cations of similar structure to the neutral [PbR2(DAPTSC)] complexes, together with a trans‐octahedral [PbPh2Cl4]2– anion and two Cl– anions. This compound decomposes in DMSO solution, probably evolving to H2DAPTSC and PbPh2Cl2(DMSO)n. In order to evaluate the changes undergone by H2DAPTSC under metallation, the X‐ray structure of the free molecule was also determined.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Ethynyltolan Platinum Complexes with (Arylalkynyl)phosphane Ligands
Authors: García Ana , Lalinde Elena , Moreno M. Teresa
Published: June 2007

The ethynyltolan mononuclear complexes cis‐[Pt(C≡CC6H4C≡CPh)2(PPh2C≡CR)2] [R = tol (2), C6H4C≡CPh (3)], which contain (arylalkynyl)phosphane ligands, were prepared, and the X‐ray molecular structure of 2 was determined. The reaction of 2 and 3 with cis‐[Pt(C6F5)2(thf)2] (thf = tetrahydrofuran) in the appropriate molar ratio gave the dinuclear platinum derivatives cis‐[{Pt(PPh2C≡CR)2(μ‐η1:η2‐Cα,Cβ‐C≡CC6H4C≡CPh)2}Pt(C6F5)2] [R = tol (4), C6H4C≡CPh (5)] and the trinuclear derivatives [{Pt(μ‐η1:η2‐Cα,Cβ‐C≡CC6H4C≡CPh)2(μ‐1κP:2η2‐Cα,Cβ‐PPh2C≡CR)2}{Pt(C6F5)2}2][R = tol (6), C6H4C≡CPh (7)], which are stabilized by a double ethynyltolan bridging system or a mixed ethynyltolan/alkynylphosphane bridging system, respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
1,3‐Dipolarophile Character of an Extremely Bulky Phosphaalkyne Mes*C≡P (Mes* = 2,4,6‐tBu3C6H2) Leading to the Formation of 1,2,4‐Diazaphospholes with Unique Hydrogen Bonding Properties
Authors: Ito Shigekazu , Miyake Hideaki , Yoshifuji Masaaki
Published: June 2007

2‐(2,4,6‐Tri‐tert‐butylphenyl)‐1‐phosphaethyne was allowed to react with trimethylsilyldiazomethane derivatives to afford the corresponding 1,2,4‐diazaphospholes via [2+3] cycloaddition followed by H/SiMe3 migration, in spite of the steric encumbrance of the substrates. The aromatic character of 1,2,4‐diazaphosphole is indicated by the NMR spectroscopic data and the X‐ray structure analysis as well as by theoretical calculation to confirm the planar delocalized ring skeleton. The crystal structure of the obtained 1,2,4‐diazaphospholes showed remarkable hydrogen bonding character in relation to molecular aggregation due to the presence of bulky aryl groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Proton Affinities in Water of Maingroup‐Element Hydrides – Effects of Hydration and Methyl Substitution
Authors: Swart Marcel , Rösler Ernst , Bickelhaupt F. Matthias
Published: June 2007

We have computed the proton affinities in water of archetypal anionic and neutral bases across the periodic table using the generalized gradient approximation (GGA) of density functional theory (DFT) at BP86/QZ4P//BP86/TZ2P. The main purpose of this work is to provide an intrinsically consistent set of values of the 298‐K proton affinities in aqueous solution of all anionic (XHn–1–) and neutral bases (XHn) constituted by maingroup‐element hydrides of groups 14–17 and the noble gases (i.e., group 18) along the periods 1–6. Hydration has little effect on the trends in PA values, especially in the case of the neutral bases. However, in the case of the anionic bases, hydration drastically reduces the magnitude of the PA values. Finally, we have studied how proton affinities in water are affected by methyl substitution at the protophilic center.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Vanadium(IV) and Oxidovanadium(IV) and ‐(V) Complexes with Soft Thioether Coordination – Synthesis, Spectroscopic and Structural Studies
Authors: Hector Andrew L. , Levason William , Middleton Annie J. , Reid Gillian , Webster Michael
Published: June 2007

VOCl3 reacts with the thioethers RS(CH2)2SR (R = Me, Et or iPr) and 1,4‐dithiane to form the first examples of VV thioether complexes, the highly reactive, intensely coloured [VOCl3(dithioether)] which have been characterised by 1H and 51V NMR, IR and UV/Vis spectroscopy. Combining VOCl3 with [9]aneS3 gives [VOCl3(κ2‐[9]aneS3)] which, upon treatment with SbCl5 gives [VOCl2(κ3‐[9]aneS3)][SbCl6]. Vanadium K‐edge extended X‐ray absorption fine structure (EXAFS) studies on three examples provided partial structural analyses for these very unstable compounds. Reaction of VCl4 with O(SiMe3)2 in CH2Cl2/MeCN followed by addition of RS(CH2)2SR (R = Me or Et) produced [VOCl2{RS(CH2)2SR}]. The crystal structure of [{VOCl2(MeSCH2CH2SMe)}4] reveals a unique tetrameric V4O4 core with each vanadium also coordinated to a chelating dithioether and two Cl ligands to complete the distorted octahedral geometry. Under rigorously anhydrous conditions VCl4 reacts with RS(CH2)2SR (R = Me, Et, iPr, Ph), 1,4‐dithiane or [9]aneS3 to form [VCl4(thioether)] which are assigned as six‐coordinate distorted octahedral species on the basis of their spectroscopic characterisation. In some cases trace hydrolysis of these compounds provides an alternative route to the [VOCl2(dithioether)] complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Precursors for Assembly of Supramolecules Containing Quadruply Bonded Cr24+ Units: Systematic Preparation of Cr2(formamidinate)n(acetate)4–n (n = 2–4)
Authors: Cotton F. Albert , Li Zhong , Murillo Carlos A.
Published: June 2007

Four quadruply bonded dichromium complexes with mixed‐ligand sets, Cr2(formamidinate)n(acetate)4–n (n = 2–4), were synthesized from reactions of anhydrous Cr2(O2CCH3)4 and formamidinate anions. The Cr–Cr bond lengths fall in the range for “supershort” Cr–Cr bonds as they vary from 1.8897(5) Å to 2.012(1) Å. The distance variation depends on the presence or absence of weak axial interactions. Because formamidinate ligands are less labile than acetate groups, these compounds may be useful building blocks for the construction of neutral supramolecules having dichromium units linked by polydentate dianions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Dinuclear Nickel–Ruthenium Complexes as Functional Bio‐Inspired Models of [NiFe] Hydrogenases
Authors: Oudart Yohan , Artero Vincent , Pécaut Jacques , Lebrun Colette , Fontecave Marc
Published: June 2007

The front cover picture shows a bioinspired model for the active site of [NiFe] hydrogenases. Interactions between the metal centers in combination with the structural features at the active site allow these complexes to serve as suitable catalysts for H2 electroproduction. Details are discussed in the article by V. Artero, M. Foutecave et al. on p. 2613 ff.
Epoxidation of karanja (Pongamia glabra) oil catalysed by acidic ion exchange resin
Authors: Goud Vaibhav V. , Patwardhan Anand V. , Dinda Srikanta , Pradhan Narayan C.
Published: June 2007

Karanja oil with an iodine value of 89 g/100 g was epoxidised in situ with aqueous hydrogen peroxide and acetic acid in the presence of Amberlite IR‐120 acidic ion exchange resin as catalyst. The effect of the operating variables on the oxirane oxygen content, as well as on the oxirane ring stability and the iodine value of the epoxidised karanja oil, were determined. The variables studied were stirring speed, hydrogen peroxide‐to‐ethylenic unsaturation molar ratio, acetic acid‐to‐ethylenic unsaturation molar ratio, temperature, and catalyst loading. The effects of these parameters on the conversion to the epoxidised oil were studied and the optimum conditions for the maximum oxirane content were established. The proposed kinetic model takes into consideration the two side reactions, namely, epoxy ring opening involving the formation of hydroxy acetate and hydroxyl groups, and the reaction between the peroxyacid and the epoxy group. The kinetic and adsorption constants of the rate equations were estimated by the best fit using Marquardt's algorithm. Good agreement between experimental and predicted data validates the proposed kinetic model. From the estimated kinetic constants, the apparent activation energy for the epoxidation reaction was found to be 11 kcal/mol.
New Proline–Oxazoline Ligands and Their Application in the Asymmetric Nozaki–Hiyama–Kishi Reaction
Authors: Hargaden Gráinne C. , Müller‐Bunz Helge , Guiry Patrick J.
Published: June 2007

Sixteen members of a new ligand class incorporating an oxazoline ring linked by an amide bond to a chiral protected proline unit were prepared in a high‐yielding four‐step synthesis from readily available chiral amino alcohols and N‐protected proline. The ligands were applied in the enantioselective Nozaki–Hiyama–Kishi allylation of benzaldehyde and gave enantioselectivities of up to 57 %. Diastereomeric ligand pairs were prepared to determine the role of each chiral centre in enantioselection.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Regio‐ and Stereoselective Diels–Alder Additions of Maleic Anhydride to Conjugated Triene Fatty Acid Methyl Esters
Authors: Biermann Ursula , Butte Werner , Eren Tarik , Haase Detlev , Metzger Jürgen O.
Published: June 2007

The thermal, solvent‐free addition of maleic anhydride to methyl calendulate (methyl 8,10‐trans,12‐cis‐octadecatrienoate) (1a) occurs with very high regio‐ and stereoselectivity at C‐8 and C‐11 of the fatty compound giving the endo‐Diels–Alder adduct 4 with retention of the cis‐configured double bond. Analogously, the Diels–Alder addition of maleic anhydride to methyl α‐eleostearate (methyl 9‐cis,11,13‐trans‐octadecatrienoate) (2a) takes place regio‐ and stereoselectively at C‐11 and C‐14 yielding the endo‐product 5 which was hydrolyzed to give the respective tricarboxylic acid 6. X‐ray diffraction analyses of compounds 4 and 6 clearly show the regio‐ and stereoselectivity of the Diels–Alder addition reactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Palladium(II)‐Catalyzed Isomerization of (Z)‐1,4‐Diacetoxy‐2‐Butene: Solvent Effects
Authors: Zawisza Anna Maria , Bouquillon Sandrine , Muzart Jacques
Published: June 2007

The isomerization of (Z)‐1,4‐diacetoxy‐2‐butene (1) catalyzed by PdCl2(MeCN)2 was studied in THF and DMF. The reaction occurs more rapidly in THF than in DMF, but in both solvents it did not proceed to complete consumption of the substrate and led to a mixture of 1, (E)‐1,4‐diacetoxy‐2‐butene (2), and 1,2‐diacetoxy‐3‐butene (3). The formation of 2 is more favored in DMF than in THF. The reactivity of 1 and the solvent effect differ strongly from those previously obtained with Pd(PPh3)4 as the catalyst. Interpretations are provided for the crucial role of the nature of both solvent and intermediates on the course of the isomerizations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Emitting Properties of the Blue‐Light Fluorophores Indolizino[3,4,5‐ab]isoindole Derivatives
Authors: Shen Yong‐Miao , Grampp Guenter , Leesakul Nararak , Hu Hong‐Wen , Xu Jian‐Hua
Published: June 2007

Indolizino[3,4,5‐ab]isoindoles 3a–3k have been synthesized by [8+2] cycloaddition reactions of the corresponding indolizines 2a–2k with benzyne in moderate yields. Cycloadditions of pyrrolo[2,1‐a]isoquinolines 4a–4c with benzyne gave the benzo[6,7]pyrrolizino[3,4,5‐ab]isoquinolines 5a–5c. Compounds 7 and 9 were similarly prepared by the reactions of 6H‐[1]benzopyrano[3,4‐a]indolizine‐6‐one (6) and 6H‐[1]benzopyrano[3′,4′:3,4]pyrrolo[2,1‐a]isoquinolin‐6‐one (8) with benzyne in 93 and 62 % yields, respectively. The electronic structures of these compounds have been calculated by the DFT method at the B3LYP/6‐31G level. Compounds 3a–3j fluoresce in the blue region (λFmax = 439–475 nm) with high quantum yields (ΦF = 0.49–0.77 in ethanol). Compounds 5a–5c and 9 are fluorescent in the green region with quantum yields of 0.44–0.77 in ethanol and compound 7 emits blue light with a quantum yield of 0.59. The electrochemical properties of these compounds have been investigated by cyclic voltammetry. Indolizino[3,4,5‐ab]isoindoles without a substituent at C‐2 (compounds 3a, 3c, 3d) or with an alkyl substituent in the framework (3i, 3k) undergo irreversible anodic oxidations and reversible cathodic reductions. Compounds 3e and 3g with an electron‐withdrawing group at C‐2, on the other hand, undergo quasi‐reversible oxidations at 1.2–1.3 V (SCE) and reversible reductions at –1.5 to –1.9 V (SCE). Therefore, compounds 3e and 3g may be promising candidates to serve as blue‐light emitters with both hole‐ and electron‐transporting ability in monolayer OLED devices, while the other indolizino[3,4,5‐ab]isoindoles (3a–3d, 3f, 3h–3i) are potential blue‐light emitters with electron‐transporting ability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Reaction of 1,2‐Unsaturated Trifluoromethyl Ketones and Their Conversion to 1‐(Trifluoromethyl)furan Derivatives
Authors: Zhang Dehui , Yuan Chengye
Published: June 2007

A novel synthetic approach leading to 1‐(trifluoromethyl)furan derivatives is reported. 4‐Aryl‐1,1,1‐trifluorobut‐3‐en‐2‐one was iodinated and subsequently reduced to give the corresponding alcohol. The resultant iodo compound was then subjected to coupling with phenylacetylene to furnish an (E)‐3‐aryl‐2‐(2‐phenylethynyl)‐1‐(trifluoromethyl)allyl alcohol, which could be cyclized by means of AgOTf to furnish a 2‐(trifluoromethyl)furan in fair yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Technique for Chemical Deposition of Pt Nanoparticles and its Applications on Biosensor Design
Authors: Wang Aifang , Ye Xiaoyan , He Pingang , Fang Yuzhi
Published: June 2007

A new glucose biosensor design based on glucose oxidase (GOD) immobilized by polypyrrole has been described in this paper. The polymerization of pyrrole was initiated by a hexachloroplatinate which itself was reduced into Pt nanoparticles and thus served as a catalyst for the H2O2 oxidation. Properties of the produced GOD modified electrode were examined and the activity of the entrapped enzyme was determined by basic application on the amperometric detection of glucose. Much better results were found comparatively with the enzyme electrode for which the enzyme was entrapped by the electrochemically polymerized polypyrrole. This kind of technique for Pt nanoparticles deposition can be generalized to many cases where polypyrrole is used.
Determination of Copper by Adsorptive Stripping Voltammetry in the Presence of Calcein Blue
Authors: Gholivand Mohammad Bagher , Sohrabi Ali , Abbasi Shahriar
Published: June 2007

An electrochemical adsorptive stripping approach is presented for the trace measurement of copper in some real samples. The method is based on the reduction of Cu2+ at pH 5.5 calcein blue (CB) containing solution at −250 mV (vs. Ag/AgCl), adsorption of CuCB complex on hanging mercury drop electrode (HMDE) and the voltammetric determination by further reduction to Cu+ at HMDE. Experimental optimum conditions were determined in the fundamental studies. At the experimental optimum conditions the adsorbed complex of Cu2+ and calcein blue gives a well defined cathodic stripping peak current at −0.135 V, which has been used for the determination of copper in the concentration range of 0.02 to 15 ng/mL with accumulation time of 90 s. The relative standard deviation (RSD) for the determination of 0.5 and 6.0 ng mL−1 were 2.60 and 1.94% respectively. (n=10). The method has been applied to the analysis of copper in analytical reagent grade salts and tap water, mineral water and drug samples with satisfactory results.
Direct Bioelectrocatalysis of PQQ‐Dependent Glucose Dehydrogenase
Authors: Ivnitski Dmitri , Atanassov Plamen , Apblett Christopher
Published: June 2007

The direct bioelectrocatalysis was demonstrated for pyrroloquinoline quinone‐dependent glucose dehydrogenase (PQQ‐dependent GDH) covalently attached to single‐walled carbon nanotubes (SWNTs). The homogeneous ink‐like SWNT suspension was used for both creating the SWNT network on the microelectrode carbon surface and for enzyme immobilization. Functionalization of the SWNT surface by forming active ester groups was found to considerably enhance SWNT solubility in water with a range from 0.1 to 1.0 mg/mL. The PQQ‐dependent GDH immobilized on the surface of the SWNTs exhibited fast heterogeneous electron transfer with a rate constant of 3.6 s−1. Moreover, the immobilized PQQ‐dependent GDH retained its enzymatic activity for glucose oxidation. A fusion of PQQ‐dependent GDH with SWNTs has a great potential for the development of low‐cost and reagentless glucose sensors and biofuel cells.
Direct and Cytochrome c Mediated Electrochemistry of Bilirubin Oxidase on Gold
Authors: Dronov Roman , Kurth Dirk G. , Scheller Frieder W. , Lisdat Fred
Published: June 2007

Direct electron transfer (DET) of bilirubin oxidase from Myrothecium verrucaria (BOD) was established on promoter‐modified gold electrodes. The electrochemical behavior of the enzyme in solution was studied by means of cyclic voltammetry evaluating the biocatalytic reduction of dioxygen. The reaction of BOD at Au electrodes was shown to be efficient only at low pH. In addition, a novel interaction between BOD and cytochrome c (cyt.c) was found. It was shown that BOD efficiently accepts cyt.c as an electron donor in both cases when cyt.c is in solution and electrostatically adsorbed. The results suggest that cyt.c can play the role of a mediator facilitating electron transfer in a pH range where no DET could be observed between the enzyme and the electrode. For the interaction between cyt.c and BOD in solution the reaction kinetics has been studied electrochemically and spectrophotometrically.
Direct fluorometric detection of paramagnetic and heavy metal ions at sub‐amol level using an aromatic polyaminocarboxylate by CZE: Combination of pre‐ and on‐capillary complexation technique
Authors: Saito Shingo , Suzuki Ryouji , Danzaka Naoki , Hikichi Atsushi , Yoshimoto Keitaro , Maeda Mizuo , Aoyama Masakazu
Published: June 2007

The low sensitivity of simple CZE for detecting metal ions is a long‐standing problem even when an LIF detection system is employed. We have successfully achieved an ultrasensitive CE‐LIF using a simple CZE mode (typical detection limit: 10−11–10−10 mol/dm3). Both the design of a newly synthesized ligand and the combination of a precapillary derivatizing technique with an on‐capillary ternary complexing technique have enabled us to achieve this extremely low LOD and high resolution of large metal complexes. The direct fluorescent detection of the paramagnetic metal ions was achieved for the first time despite their intrinsic fluorescent quenching nature. The fluorescent ligand (L) consists of a polyaminocarboxylate chelating moiety, a strongly emissive fluorescein moiety and a spacer connecting the two portions. The migration behavior of various metal–L complexes was investigated. The resolution among the complexes was improved by the introduction of a ternary complex equilibrium of the kinetically stable mother complexes with OH− ion. The analytical potential of our simple system was examined, and it was proved that the system was one of the most sensitive methods without the need for any preconcentration process.
CE characterization of potential toxic labile iron in colloidal parenteral iron formulations using off‐capillary and on‐capillary complexation with EDTA
Authors: Jahn Markus R. , Mrestani Yahya , Langguth Peter , Neubert Reinhard H. H.
Published: June 2007

The present study describes the application of CZE to investigate the portion of labile iron in the following parenteral formulations: iron gluconate, iron saccharate, and iron dextran. Labile iron was detected as Fe(III)‐chelate of EDTA at 246 nm. When EDTA was incubated with the formulations before electrophoresis, labile iron, or chelatable iron, respectively, was detected in all formulations, mostly in iron gluconate and iron saccharate. It was observed that the amount of iron released is time‐ and pH‐dependent. In contrast, when EDTA was separately injected before the formulation sharp peaks of the Fe(III)‐chelate were detected only after injection of iron gluconate. This type of labile iron can be described as “electrophoretically free” iron. CE provides thus a new method to characterize potential toxic, labile iron in parenteral iron formulations.
Parallel analysis of antimicrobial activities in microbial community by SSCP based on CE
Authors: Chung Joo Hee , Park Young Seoub , Kim Jin , Shin Gi Won , Nam Myung Hee , Oh Min‐Kyu , Kim Chan Wha , Jung Gyoo Yeol , Hyun Park Jin
Published: June 2007

Conventional antimicrobial activity analyses such as the broth dilution method and disk diffusion test are considerably demanding processes for new antimicrobial agent discovery and sensitive diagnosis of infectious diseases. Here, we developed a new antimicrobial activity analysis system using CE‐based SSCP (CE‐SSCP) combined with 16S rRNA gene‐specific PCR (PCR/CE‐SSCP). Using this method, the population change in the microbial community in response to specific antimicrobial agents could be quantified with a high sensitivity and accuracy from a small sample amount. Using a mixture of microorganisms comprising Escherichia coli, Corynebacterium glutamicum, Acinetobacter calcoaceticus, and Staphylococcus aureus as a model system, the linear correlation between the genomic DNA concentrations and peak areas in 16S rRNA gene‐specific PCR/CE‐SSCP was determined; consequently, quantification of cell concentrations could be demonstrated using this method. Compared to the minimum inhibitory concentration (MIC) values from the conventional broth dilution method, this new system provided almost the same MIC values for popular antimicrobial agents such as kanamycin, spectinomycin, and streptomycin. The results demonstrated that the newly developed method can be a substitute for the conventional antimicrobial analysis method and highlighted its high potential in the areas of new antimicrobial agent discovery and clinical diagnosis.
2‐DE using hemi‐fluorinated surfactants
Authors: Starita‐Geribaldi Mireille , Thebault Pascal , Taffin de Givenchy Elisabeth , Guittard Frederic , Geribaldi Serge
Published: June 2007

The synthesis of hemi‐fluorinated zwitterionic surfactants was realized and assessed for 2‐DE, a powerful separation method for proteomic analysis. These new fluorinated amidosulfobetaine (FASB‐p,m) were compared to their hydrocarbon counterparts amidosulfobetaine (ASB‐n) characterized by a hydrophilic polar head, a hydrophobic and lipophilic tail, and an amido group as connector. The tail of these FASB surfactants was in part fluorinated resulting in the modulation of its lipophilicity (or oleophobicity). Their effect on the red blood cell (RBC) membrane showed a specific solubilization depending on the length of the hydrophobic part. A large number of polypeptide spots appeared in the 2‐DE patterns by using FASB‐p,m. The oleophobic character of these surfactants was confirmed by the fact that Band 3, a highly hydrophobic transmembrane protein, was not solubilized by these fluorinated structures. The corresponding pellet was very rich in Band 3 and could then be solubilized by using a strong detergent such as amidosulfobetaine with an alkyl tail containing 14 carbon atoms (ASB‐14). Thus, these hemi‐fluorinated surfactants appeared as powerful tools when used at the first step of a two‐step solubilization strategy using a hydrocarbon homologous surfactant in the second step.
Fabrication and performance of fiber electrophoresis microchips
Authors: Chen Zhi , Zhang Luyan , Chen Gang
Published: June 2007

A method based on the in situ polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of a novel separation platform, fiber electrophoresis microchip. To demonstrate the concept, prepolymerized MMA molding solution containing a UV initiator was sandwiched between a poly(methyl methacrylate) (PMMA) cover plate and a PMMA base plate bearing glycerol‐permeated fiberglass bundles and was exposed to UV light. During the UV‐initiated polymerization, the fiberglass bundles were embedded in the PMMA substrate to form fiberglass‐packed microchannels. When the glycerol in the fiberglass bundles was flushed away with water, the obtained porous fiberglass‐packed channels could be employed to perform electrophoresis separation. Scanning electron micrographs (SEMs) and microscopic images offered insights into the fiber electrophoresis microchip. The analytical performance of the novel microchip has been demonstrated by separating and detecting dopamine and catechol in connection with end‐column amperometric detection. The fiber‐based microchips can be fabricated by the new approach without the need for complicated and expensive lithography‐based microfabrication techniques, indicating great promise for the low‐cost production of microchips, and should find a wide range of applications.
High‐throughput multiplex microsatellite marker assay for detection and quantification of adulteration in Basmati rice (Oryza sativa)
Authors: Archak Sunil , Lakshminarayanareddy V. , Nagaraju Javaregowda
Published: June 2007

Basmati rice is a very special type of aromatic rice known world‐wide for its extra long grains and pleasant and distinct aroma. Traditional Basmati rice cultivars, confined to Indo‐Gangetic regions of the Indian subcontinent, are often reported to be adulterated with crossbred Basmati varieties and long‐grain non‐Basmati varieties in the export market. At present, there is no commercial scale technology to reliably detect adulteration. We report here a CE‐based multiplex microsatellite marker assay for detection as well as quantification of adulteration in Basmati rice samples. The single‐tube assay multiplexes eight microsatellite loci to generate variety‐specific allele profiles that can detect adulteration from 1% upwards. The protocol also incorporates a quantitative‐competitive PCR‐based analysis for quantification of adulteration. Accuracy of quantification has been shown to be ±1.5%. The experiments used to develop and validate the methodology are described.
Method validation of in vitro RNA transcript analysis on the Agilent 2100 Bioanalyzer
Authors: Sodowich Bruce I. , Fadl Irini , Burns Craig
Published: June 2007

The Agilent 2100 Bioanalyzer can characterize in vitro RNA transcripts for their integrity, purity, concentration, and size. The results are comparable to denatured agarose electrophoresis with ethidium bromide staining and UV spectrophotometry combined. In this report, we describe our strategy for validating this method following the International Conference on Harmonization guidelines. The assay has a linear range of quantitation between 500 and 25 ng/μL. Quantitation accuracy is within ±20% of measurements produced from spectrophotometry and sizing accuracy is within ±7% based on theoretical sizes. Concentration and sizing measurements within a single assay produce RSDs that are <10 and <2%, respectively, indicating good precision. The method also maintains a tolerable precision when altering operator, day, and reagent kit lot. The RSD for quantitation is ≤25 and <2% for sizing. The LOQ and LOD are 15.4 and 5.4 ng/μL based on experimentation, producing values similar to those specified by the manufacturer. The Bioanalyzer can differentiate between the RNA transcript and DNA contamination, and protein contamination quenches the RNA transcript signal. The effect of the ionic strength of the buffer on RNA analysis is also examined. Limitations of this method and future applications are discussed.
Integration of continuous‐flow sampling with microchip electrophoresis using poly(dimethylsiloxane)‐based valves in a reversibly sealed device
Authors: Li Michelle W. , Martin R. Scott
Published: June 2007

Here we describe a reversibly sealed microchip device that incorporates poly(dimethylsiloxane) (PDMS)‐based valves for the rapid injection of analytes from a continuously flowing stream into a channel network for analysis with microchip electrophoresis. The microchip was reversibly sealed to a PDMS‐coated glass substrate and microbore tubing was used for the introduction of gas and fluids to the microchip device. Two pneumatic valves were incorporated into the design and actuated on the order of hundreds of milliseconds, allowing analyte from a continuously flowing sampling stream to be injected into an electrophoresis separation channel. The device was characterized in terms of the valve actuation time and pushback voltage. It was also found that the addition of sodium dodecyl sulfate (SDS) to the buffer system greatly increased the reproducibility of the injection scheme and enabled the analysis of amino acids derivatized with naphthalene‐2,3‐dicarboxaldehyde/cyanide. Results from continuous injections of a 0.39 nL fluorescein plug into the optimized system showed that the injection process was reproducible (RSD of 0.7%, n = 10). Studies also showed that the device was capable of monitoring off‐chip changes in concentration with a device lag time of 90 s. Finally, the ability of the device to rapidly monitor on‐chip concentration changes was demonstrated by continually sampling from an analyte plug that was derivatized upstream from the electrophoresis/continuous flow interface. A reversibly sealed device of this type will be useful for the continuous monitoring and analysis of processes that occur either off‐chip (such as microdialysis sampling) or on‐chip from other integrated functions.
Rapid desalting and protein recovery with phenol after ammonium sulfate fractionation
Authors: Wang Wei , Liu Quan‐Jun , Cui Hong
Published: June 2007

Ammonium sulfate (AS) fractionation is often used in protein and enzyme purification; however, the resultant protein pellets have a high salt content and desalting by dialysis is required prior to next analysis. Here, we have developed a phenol‐based method for quick desalting and concentrating proteins after AS fractionation of complex olive leaf protein extract. After redissolving, AS precipitates were desalted with phenol extraction and the abundance of β‐glucosidase in each fraction was monitored with a specific antibody. The results of electrophoresis and Western blot showed the feasibility of the method. The method is quick and universal, and does not need much technique.

Ammonium sulfate (AS) is the most common salt used to fractionate complex protein samples by step‐wise precipitation [1]. AS fractionation provides crude purification of proteins away from nonproteins and it is typically included in protein purification protocols. However, protein precipitates obtained from AS fractionation have a high salt content, and need to be desalted prior to the next analysis. One way to remove excess AS is by dialyzing protein samples against a buffer low in salt content. This works fine though time consuming. Additionally, after dialysis, it is often needed to concentrate dilute protein solutions because the analysis requires small volumes, such as in gel electrophoresis. Recent research in plant proteomics calls for a rapid method for desalting and protein recovery after AS fractionation.
Development of in‐tube solid‐phase microextraction coupled to pressure‐assisted CEC and its application to the analysis of propranolol enantiomers in human urine
Authors: Lin Bo , Zheng Ming‐Ming , Ng Siu‐Choon , Feng Yu‐Qi
Published: June 2007

A successful hyphenation of in‐tube solid‐phase microextraction (SPME) and pressure‐assisted CEC (pCEC) was developed by installing a poly(methacrylic acid‐co‐ethylene glycol dimethacrylate) monolithic capillary to the six‐port valve in a CEC system. The device designed was appropriate for on‐line in‐tube SPME coupled to pCEC or μHPLC. The evaluation of this hyphenation was first carried out for in‐tube SPME‐μHPLC with analytical capillaries packed with 3 μm octadecyl silica (ODS). Theobromine (TB), theophylline (TP), and caffeine (CA) were chosen as model drugs for an easy comparison with the results obtained by in tube SPME‐HPLC. The detection limits of these three analytes were improved more than 100 times when compared with the direct analysis by μHPLC. Then in‐tube SPME‐pCEC with CEC capillaries packed with perphenylcarbamoylated β‐CD‐bonded silica particles was applied to the determination and analysis of propranolol enantiomers in human urine. Under optimal extraction and separation conditions, the experimental LODs were 4 and 7 ng/mL for (S)‐propranolol and (R)‐propranolol, respectively. The calibration curves showed good linearity for both (S)‐propranolol (R2 = 0.9997) and (R)‐propranolol (R2 = 0.9996) over the concentration range from 20 to 5000 ng/mL. Reproducibility of the method was also investigated with intra‐ and interday precisions lower than 10% for both enantiomers at different concentration levels.
Seismic fragility analysis: Application to simple linear and nonlinear systems
Authors: Kafali Cagdas , Grigoriu Mircea
Published: June 2007

Seismic fragility of a structural, nonstructural and/or geotechnical system is the probability that a system response exceeds a critical value under seismic ground motions of specified intensities. Fragility curves are plots of system fragilities versus a scalar measure of seismic intensity. Traditionally, peak ground acceleration (PGA) has been used as an intensity measure. Recent studies show that pseudo‐spectral acceleration provides a superior measure of seismic intensity than PGA.

It is shown that pseudo‐spectral acceleration may not be a satisfactory measure of seismic intensity for the fragility analysis of nonlinear systems, so that fragility curves based on pseudo‐spectral acceleration are not recommended for these systems. An alternative intensity measure based on two parameters, the earthquake moment magnitude m and the distance r from the seismic source to system site, is proposed for the fragility analysis of nonlinear systems. The relationship between a system probability of failure and (m, r) is called fragility surface. Findings are for single degree of freedom systems and synthetic
ground motion records. Copyright © 2007 John Wiley & Sons, Ltd.
A robust interference cancellation technique for DS‐UWB systems using fuzzy step size LMS algorithm
Authors: Cheng Chia‐Hsin , Wen Jyh‐Horng , Chen Yu‐Fan , Lin Jen‐Yung
Published: June 2007

This paper discusses a direct‐sequence ultra‐wideband (DS‐UWB) system that uses the least mean square (LMS) adaptive filter for interference cancellation. Compared to the conventional LMS (C‐LMS) algorithm, the fuzzy step size LMS (FSS‐LMS) algorithm which we propose can perform rapid convergence with a low steady‐state fluctuation error. The sequential partial update scheme is used in the proposed FSS‐LMS algorithm to reduce the system complexity without trading off the bit error rate (BER). Simulations are conducted to evaluate the convergence and tracking behaviour of the proposed LMS algorithm. The BER of the DS‐UWB system in a realistic UWB channel is also investigated. Copyright © 2007 John Wiley & Sons, Ltd.
Primary mediastinal B‐cell lymphoma
Authors: Boleti E , Johnson P W M
Published: June 2007

Primary mediastinal B‐cell lymphoma (PMBCL) is a sub‐type of the heterogeneous diffuse large B‐cell lymphoma category, and comprises approximately 5% of all non‐Hodgkin's lymphomas (NHL). It was first recognized as a distinct clinico‐pathologic entity 20 years ago, and recent work has further characterized specific molecular features. Gene expression profiling has suggested a partial overlap with nodular sclerosing Hodgkin lymphoma (HL), with which it shares some clinical features. The optimal management remains a matter of debate. There is uncertainty as to whether weekly alternating chemotherapy regimens may be more effective than CHOP, whether consolidation radiotherapy (RT) to the mediastinum is always required, whether PET scanning can be used to determine this, and whether the use of rituximab as part of initial therapy will change the answers to these questions. The International Extranodal Lymphoma Study Group (IELSG) 26 clinicopathologic study of PMBCL, which has recently opened, represents a first attempt to gather data prospectively on some of these issues. Copyright © 2007 John Wiley & Sons, Ltd.
Patients with bisphosphonates‐associated osteonecrosis of the jaw have reduced circulating endothelial cells
Authors: Allegra A , Oteri G , Nastro E , Alonci A , Bellomo G , Del Fabro V , Quartarone E , Alati C , De Ponte FS , Cicciù D , Musolino C
Published: June 2007

Osteonecrosis of the jaws (ONJ) associated with the use of bisphosphonates is a newly described entity. To elucidate the mechanism leading to ONJ and to test the hypothesis that in patients with ONJ the bisphosphonates may interfere with endothelial cell proliferation, using flow cytometric analysis we evaluated the number of circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) in eight patients with bisphosphonate treatment and osteonecrosis, eight multiple myeloma (MM) patients with bisphosphonates treatment without ONJ and five normal subjects. MM patients showed an increase of CD34+ cells with respect the control subjects and ONJ subjects. EPCs and CECs were higher in MM patients compared to controls and ONJ patients. ONJ patients showed a decrease of EPCs compared to control subjects while CECs were similar to the controls group. Our results seem to show the possibility that bisphosphonates could have a antiangiogenic effect and a suppressive effect on CECs of patients with ONJ. Copyright © 2007 John Wiley & Sons, Ltd.
Factors controlling nitrogen release from two forested catchments with contrasting hydrochemical responses
Authors: Christopher Sheila F. , Mitchell Myron J. , McHale Michael R. , Boyer Elizabeth W. , Burns Douglas A. , Kendall Carol
Published: June 2007

Quantifying biogeochemical cycles of nitrogen (N) and the associated fluxes to surface waters remains challenging, given the need to deal with spatial and temporal variability and to characterize complex and heterogeneous landscapes. We focused our study on catchments S14 and S15 located in the Adirondack Mountains of New York, USA, which have similar topographic and hydrologic characteristics but contrasting stream nitrate ($\hbox{NO}_{3}^{-}$) concentrations. We characterized the mechanisms by which $\hbox{NO}_{3}^{-}$ reaches the streams during hydrological events in these catchments, aiming to reconcile our field data with our conceptual model of factors that regulate nutrient exports from forested catchments. Combined hydrometric, chemical and isotopic (δ$\hbox{NO}_{3}^{-}$) data showed that the relative contributions of both soil and ground water sources were similar between the two catchments. Temporal patterns of stream chemistry were markedly different between S14 and S15, however, because the water sources in the two catchments have different solute concentrations. During late summer/fall, the largest source of $\hbox{NO}_{3}^{-}$ in S14 was till groundwater, whereas shallow soil was the largest $\hbox{NO}_{3}^{-}$ source in S15. $\hbox{NO}_{3}^{-}$ concentrations in surface water decreased in S14, whereas they increased in S15 because an increasing proportion of stream flow was derived from shallow soil sources. During snowmelt, the largest sources of $\hbox{NO}_{3}^{-}$ were in the near‐surface soil in both catchments. Concentrations of $\hbox{NO}_{3}^{-}$ increased as stream discharge increased and usually peaked before peak discharge, when shallow soil water sources made the largest contribution to stream discharge. The timing of peaks in stream $\hbox{NO}_{3}^{-}$concentrations was affected by antecedent moisture conditions. By elucidating the factors that affect sources and transport of N, including differences in the soil nutrient cycling and hydrological characteristics of S14 and S15, this study contributes to the overall conceptualization of $\hbox{NO}_{3}^{-}$ release from temperate forested catchments. Copyright © 2007 John Wiley & Sons, Ltd.
A field‐based assessment of oxygen supply to incubating Atlantic salmon (Salmo salar) embryos
Authors: Greig Stuart , Sear David , Carling Paul
Published: June 2007

Oxygen fluxes through artificially created salmon redds within four UK rivers were quantified and assessed against survival to hatching of Atlantic salmon embryos. All sites recorded high spatial variability in survival. Minimum survival to hatching was zero at all sites. Maximum survival to hatching ranged from 35% to 91%. Mean survival to hatching ranged from 8·7% to 71%.

Intra‐ and inter‐site variations in rates of oxygen supply were observed. Generally, interstitial dissolved oxygen concentrations declined over the incubation period from a maximum recorded directly after redd creation, although localized fluctuations were recorded. Similarly, interstitial flow velocities declined over the incubation period from a maximum directly after redd creation to a minimum at hatching. With respect to the causes of embryo mortalities, oxygen supply was shown to be a stronger determinant of survival than interstitial oxygen concentration or interstitial flow velocity.

To improve delineation of potential causes of embryo mortalities in the field, the statistical analysis was integrated within mass transfer theory of the processes controlling respiration to determine the likely mechanisms inhibiting respiration. Based on this analysis, mortalities were assessed to have resulted from periods of lethal oxygen concentrations, from periods of interstitial flow velocities that were insufficient to remove metabolic waste, or from combinations of oxygen concentration and interstitial flow that did not support respiratory requirements. A set of oxygen‐supply‐related thresholds for assessing incubation habitat quality are proposed. Copyright © 2007 John Wiley & Sons, Ltd.
Investigation of groundwater residence times during bank filtration in Berlin: a multi‐tracer approach
Authors: Massmann Gudrun , Sültenfuß Jürgen , Dünnbier Uwe , Knappe Andrea , Taute Thomas , Pekdeger Asaf
Published: June 2007

Berlin relies on induced bank filtration from a broad‐scale, lake‐type surface water system. Because the surface water contains treated sewage, wastewater residues are present in surface water and groundwater. Multiple environmental tracers, including tritium and helium isotopes (3H, 3He, 4He), stable isotopes (δ18O and δ2H) and a number of persistent sewage indicators, such as chloride, boron and a selection of pharmaceutical residues (phenazone‐type analgesics and their metabolites, carbamazepine and anthropogenic gadolinium, Gdexcess), were used to estimate travel times from the surface water to individual production and observation wells at two sites. The study revealed a strong vertical age stratification throughout the upper aquifer, with travel times varying from a few months to several decades in greater depth. Whereas the shallow bank filtrate is characterized by the reflection of the time‐variant tracer input concentrations and young 3H/3He ages, the deeper, older bank filtrate displays no tracer seasonality, 3H/3He ages of a few years to decades and strongly deviating concentrations of several pharmaceutical residues, reflecting concentrations of the source surface water over time. The phenazone‐type pharmaceuticals persist in the aquatic environments for decades. Bank filtration in Berlin is only possible at the sandy lakeshores. In greater water depth, impermeable lacustrine sapropels inhibit infiltration. The young bank filtrate originates from the nearest shore, whereas the older bank filtrate infiltrates at more distant shores. This paper illustrates the importance of using multiple tracer methods, capable of resolving a broad range of residence times, to gain a comprehensive understanding of time‐scales and infiltration characteristics in a bank filtration system. Copyright © 2007 John Wiley & Sons, Ltd.
Trends of precipitation in Beijiang River Basin, Guangdong Province, China
Authors: Luo Yan , Liu Shen , Fu ShengLei , Liu Jingshi , Wang Guoqin , Zhou Guoyi
Published: June 2007

An analysis of spatial and temporal trends of precipitation in Beijiang River basin, Guangdong Province, China during 1959–2003 was performed using 17 time series (including monthly, annual, wet season, dry season, early flood period and late flood period totals) both on station based and sub‐basin based data sets. Two nonparametric methods (Mann–Kendall and Sen's T) were used for data analysis. The results showed that (1) downward trends of temporal distribution were mostly detected during the early flood period, especially in May, while upward trends were observed in July and the dry season; (2) downward trends of spatial distribution were mostly detected in the southern Beijiang River basin, while upward trends were observed north of this area. Our results indicated a delayed rainy season and a northward trend of the precipitation belt compared to recent years. Copyright © 2007 John Wiley & Sons, Ltd.
Some infinite families of large sets of Kirkman triple systems
Authors: Yuan Landang , Kang Qingde
Published: June 2007

A large set of Kirkman triple systems of order v, denoted by LKTS(v), is a collection {(X, Bi) : 1 ≤ i ≤ v − 2}, where every (X,Bi) is a KTS(v) and all Bi form a partition of all triples on X. Many researchers have studied the existence of LKTS(v) for a long time. In [13], the author introduced a concept—large set of generalized Kirkman systems (LGKS), which plays an important role in the discussion of LKTS. In this article, we give a new construction for LGKS and obtain some new results of LKTS, that is, there exists an LKTS(6u + 3) for u = qn, where n ≥ 1, q ≡ 7 (mod 12) and q is a prime power. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 202–212, 2008
1‐rotational k‐factorizations of the complete graph and new solutions to the Oberwolfach problem
Authors: Buratti Marco , Rinaldi Gloria
Published: June 2007

We consider k‐factorizations of the complete graph that are 1‐rotational under an assigned group G, namely that admit G as an automorphism group acting sharply transitively on all but one vertex. After proving that the k‐factors of such a factorization are pairwise isomorphic, we focus our attention to the special case of k = 2, a case in which we prove that the involutions of G necessarily form a unique conjugacy class. We completely characterize, in particular, the 2‐factorizations that are 1‐rotational under a dihedral group. Finally, we get infinite new classes of previously unknown solutions to the Oberwolfach problem via some direct and recursive constructions. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 87–100, 2008