bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactions of Dry Arenediazonium o‐Benzenedisulfonimides with Triorganoindium Compounds
Authors: Barbero Margherita , Cadamuro Silvano , Dughera Stefano , Giaveno Cinzia 
Published: August 2006

AbstractThe reaction between various arenediazonium o‐benzenedisulfonimides and triorganoindium compounds is described. Depending on the reaction conditions, it is possible to obtain biaryls (16 examples, average yield of 79 %) or diaryldiazenes (18 examples, average yield of 81 %). o‐Benzenedisulfonimide can be recovered and reused to prepare additional arenediazonium o‐benzenedisulfonimides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cover Picture: Recent Developments in the Syntheses of the Epothilones and Related Analogues (Eur. J. Org. Chem. 18/2006)
Authors: Watkins E. Blake , Chittiboyina Amar G. , Avery Mitchell A. 
Published: August 2006

AbstractThe cover picture shows a representative collection of some of the more potent, naturally occurring epothilones and their synthetic analogues. Several of these are currently in clinical trials. Colored ribbons are routinely used to bring attention to a particular disease and the ongoing search for a cure, especially cancer. The ribbon shown is white, depicting no particular cancer, but rather cancers in general. Details are presented in the Microreview by E. B. Watkins, A. G. Chittiboyina, and M. A. Avery on p. 4071 ff.
Selective Determination of Quercetin Using Carbon Nanotube‐Modified Electrodes
Authors: Xu Guang‐Ri , Kim Sunghyun 
Published: August 2006

AbstractElectrochemical detection of quercetin has been carried out on glassy carbon electrodes modified with carbon nanotubes and Nafion (GC/Nafion‐CNT). GC/Nafion‐CNT electrodes did not show passivation effect that occurs on the unmodified electrodes and displayed better stability and reproducibility. Quercetin oxidation was most favorable in acidic conditions and current gradually decreased as the solution pH increased. No oxidation was observed when two OH groups in a catechol moiety were fully deprotonated. These electrodes enabled selective determination of quercetin in the presence of interfering species such as ascorbic acid, uric acid, glucose, and catechol in large excess. Quantification of quercetin in a yellow onion has been made and favorably compared with reported values. Good selectivity and high sensitivity obtained by Osteryoung sSquare‐wave voltammetry can open new possibilities of direct quercetin determination in vegetables with a minimal sample treatment.
Voltammetric Characterization of Micro‐ and Submicrometer‐Electrode Arrays of Conical Shape for Electroanalytical Use
Authors: Daniele Salvatore , De Faveri Eddy , Kleps Irina , Angelescu Anca 
Published: August 2006

AbstractDensely packed micro‐ and submicrometer electrode arrays of platinum and gold (the nominal number, N, of electrodes in each array varies between 225 and 3600) are fabricated by photolithographic technique and vapor deposition processes of metal films. The electrodes are conical‐shaped and only their apexes are exposed to the electrolytic solution. The electrode arrays are characterized electrochemically in Ru(NH3)6Cl3 aqueous solutions by using cyclic voltammetry at low scan rates, to establish the number of electrochemically active electrodes (Nac) in each array; the geometric characterization is performed by scanning electron microscopy. All the investigated arrays provide steady‐state voltammograms, indicating diffusionally independent behavior of each microelectrode. The number of microelectrodes that are active in the fabricated arrays depends on microelectrode density. In particular, for the arrays with N=3600 and N=225, the fraction of active sites is about 45% and 90%, respectively. The analytical performance of some of the Pt version of the arrays is tested in hydrogen peroxide solutions, allowing verifying that linear calibration plots over the concentration range (0.1–20 mM) are obtained. This dynamic range is larger than that typically recorded at smooth polycrystalline platinum electrodes (0.5–5 mM), and the better performance is attributed to both the higher aspect ratio of the cone geometry and the higher mass transport associated to each microelectrode of the array. Reproducibility (within 3.5%, r.s.d.) and long‐term stability (within 5%, r.s.d., after 8 h continuous use) of the electrode systems are satisfactory. A low detection limit, based on the signal to noise ratio equal to 3, of 0.05 mM is found, which is adequate for a rapid monitoring of H2O2 in real samples and industrial processes.
Tagging of Model Amphetamines with Sodium 1,2‐Naphthoquinone‐4‐sulfonate: Application to the Indirect Electrochemical Detection of Amphetamines in Oral (Saliva) Fluid
Authors: Goodwin Alexander , Banks Craig E. , Compton Richard G. 
Published: August 2006

AbstractProof‐of‐concept is shown for the indirect electrochemical detection of model amphetamines, D‐amphetamine sulfate and pseudoephedrine, based on the labeling of the amphetamine models with sodium 1,2‐naphthoquinone‐4‐sulfonate (NQS). The presence of the amphetamine models is monitored via either the reduction in the magnitude of the voltammetric peak corresponding to the electrochemical reduction of the quinone functionality of the sodium 1,2‐naphthoquinone‐4‐sulfonate or via growth of a new voltammetric peak related to reaction between the amphetamine model and NQS, both of which are well resolved from one another. The protocol is shown to be successful in artificial saliva and authentic human oral (saliva) fluid. Such a protocol may be particularly attractive for roadside testing of amphetamines in drug drivers.
Collagen‐Like Peptide as a Matrix for Enzyme Immobilization in Electrochemical Biosensors
Authors: Yemini Miri , Xu Peng , Kaplan David L. , Rishpon Judith 
Published: August 2006

AbstractAn efficient enzyme immobilization technique is described in which well‐organized collagen peptide monolayers are used as a scaffold upon which horseradish peroxidase is anchored on gold electrode surfaces. The resulting electrode presents reproducible amperometric responses at an applied potential of −0.1 V with a range of linearity for peroxides. These results suggest that triple helical collagen can be used for specific immobilization of HRP with advantages of low price, simplicity and biocompatibility. The results are significant for the control of biomolecular self‐assembly in the intrinsic electric devices.
Iron(III) Oxide Graphite Composite Electrodes: Application to the Electroanalytical Detection of Hydrazine and Hydrogen Peroxide
Authors: Šljukić Biljana , Banks Craig E. , Crossley Alison , Compton Richard G. 
Published: August 2006

AbstractComposite electrodes based on iron(III) oxide, Fe2O3, carbon powder and epoxy resin have been prepared and characterized using electrochemical methods and X‐ray photoelectron spectroscopy (XPS). Initially composite electrodes were made by mixing micron sized carbon powder surface with iron(III) oxide. However, the voltammetric responses were unsatisfactory. Therefore, a new type of composite electrodes was made using carbon powder modified with iron(III) oxide via a wet impregnation procedure. This technique involves saturation of the carbon powder with iron(III) nitrate followed by thermal treatment at ca. 623 K forming iron(III) oxide on the surface of the carbon powder.
Genetic mutation analysis by CE with LIF detection using inverse‐flow derivatization of DNA fragments
Authors: Sang Fuming , Ren Haixia , Ren Jicun 
Published: August 2006

AbstractInverse‐flow derivatization is a novel approach to obtain fluorescent DNA derivatives in DNA analysis based on CE with LIF detection. In the present work, we want to explore the feasibility of the application of this method into the mutation detection based on constant denaturant capillary electrophoresis (CDCE) and SSCP analysis. The DNA fragments were first amplified by PCR using a pair of common primers without fluorescent label, and then the mutations were determined by CDCE or SSCP analysis based on CE‐LIF with inverse‐flow derivatization of DNA fragments. The experimental conditions were investigated systematically, and different labeling modes including inverse‐flow derivatization, on‐column derivatization and fluorescent labeled primer technique were compared. The inverse‐flow derivatization was successfully used in the detection of C677T mutation in the methylenetetrahydrofolate reductase gene by CDCE or SSCP analysis. Our preliminary results demonstrate that inverse‐flow derivatization is very simple, inexpensive and sensitive and well suitable for the genetic analysis in clinical diagnosis.
Alkaline leaching of printed circuit board sludge
Authors: Hu S.H. , Wu J.Y. , Yen F.S. , Tsai M.S. 
Published: August 2006

AbstractThe purpose of this study was to develop a treatment procedure for processing aluminum‐contaminated sludge produced from the coagulation/flocculation process of wastewater treatment in the manufacture of printed circuit boards (PCBs). In this study, the reagent sodium hydroxide (2 N) was used to leach the heavy metal sludge and the dissolution of sludge's aluminum content was roughly 70%. The weight loss of the heavy metal sludge was caused by the dissolution of aluminum content of nearly 20%. Although dissolution of a small amount of copper occurred simultaneously during this leaching process, the dissolution of copper content was restricted within 0.72% in the leaching operation and the copper content was concentrated in the residue to increase the copper level.The large amounts of sodium hydroxide and Al3+ remaining in the leachate were recycled as neutralization and coagulation agents in wastewater treatment. Synthetic heavy metal wastewater was neutralized with the preceding leachate to estimate the reuse feasibility of recovered coagulant. The heavy metal concentration of the effluent met regulation standards after neutralization and precipitation. The settling rate could be significantly enhanced by the addition of 100 ppm supplemental polyacrylamide (PAM). © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Practical seismic upgrade strategy for substation equipment based on performance indices
Authors: Shumuta Yoshiharu 
Published: August 2006

AbstractThis paper presents an upgrade strategy for substation equipment under seismic risk. In Japan, existing old equipment does not often meet the present seismic design standards and the seismic damage is concentrated on such old equipment. This problem is widely recognized as a typical feature of advanced countries. The proposed method helps managerial decisions pertaining to the prioritizing of upgrading the huge number of existing equipment. In order to prioritize the equipment to be upgraded, practitioners have discussed it from various points of view including earthquake resistant capacity of equipment, seismic performance of whole power system and cost effectiveness of equipment upgrading. Thus, the proposed method consists of four different performance indices to quantitatively evaluate these factors. For numerical examples, the proposed method is applied to a hypothetical power system to discuss the advantages and disadvantages of the proposed indices. Copyright © 2006 John Wiley & Sons, Ltd.
Correlating specific conductivity with total hardness in gypsum karst waters
Authors: Krawczyk Wiesława Ewa , Ford Derek C. 
Published: August 2006

AbstractModern digital conductivity meters are readily portable, robust, cheap, and give precisely reproducible values of specific electrical conductivity (SpC, in µS cm−1). Here we investigate the accuracy of their estimates of the amounts of gypsum dissolved in waters collected in gypsum karst terrains, expressed as total hardness (TH) in mg L−1 of CaSO4·2H2O (GYP). Total dissolved solid concentrations (TDS) are also considered. Curves obtained with the program PHREEQC, for the dissolution of pure gypsum in water at 25 C, are compared with 574 comprehensive water chemical analyses selected from gypsum karst studies in Europe and the Americas. Principal common and foreign ions encountered are the BNC group (bicarbonates, nitrates, chlorides). It is found that GYP = 1·12·SpC + 62 where BNC < 33% (Cl− < 5%), with one standard error <5% for waters with SpC > 2400 µS cm−1; GYP = 0·74·SpC + 777 where BNC < 33% (5% ≤ Cl− < 15%), with one standard error <10% for waters with SpC > 3100 µS cm−1; GYP = 0·97·SpC − 209 where BNC < 33% and Cl− ≥ 15%, with one standard error <10% for samples with SpC > 4300 µS cm−1. There are similar results for the more complex waters found in gypsum karsts where much carbonate rock or salt is also present, to the limit of BNC < 50% for what may reasonably be defined as ‘gypsum waters’. Values of R2 for linear correlations of different subsets of the water samples range from 0·69 to 0·96, the majority being >0·8. Copyright © 2006 John Wiley & Sons, Ltd.
Compensatory activations in patients with multiple sclerosis during preserved performance on the auditory N‐back task
Authors: Forn Cristina , Barros‐Loscertales Alfonso , Escudero Joaquín , Benlloch Vicente , Campos Salvador , Antònia Parcet Maria , Ávila César 
Published: August 2006

AbstractRecent fMRI studies have suggested that multiple sclerosis (MS) patients show adaptive cortical changes (i.e., compensatory mechanisms) during motor and cognitive tasks to limit the clinical impact of tissue injury. In this study, we investigated the activation pattern during the auditory n‐back working memory (WM) paradigm in a group of 17 MS patients and 10 healthy controls with preserved performance in WM tasks. Compared with healthy controls, MS patients showed significantly greater bilateral activation in prefrontal cortex (BA 44), and the insula. These findings were similar to those obtained in previous studies showing that compensatory mechanisms during WM tasks in MS may be based on the use of prefrontal areas adjacent to those involved in the task. Hum. Brain Mapp, 2007. © 2006 Wiley‐Liss, Inc.
Solution NMR and X‐Ray Structural Studies on Phthalocyaninatoiron Complexes
Authors: Fernández Ignacio , Pregosin Paul S. , Albinati Alberto , Rizzato Silvia , Spichiger‐Keller Ursula E. , Nezel Tomas , Fernández‐Sánchez Jorge F. 
Published: August 2006

AbstractThe addition of primary amines as solubilizing reagents for phthalocyaninatoiron complexes is shown to afford six‐coordinate bis(amine)phthalocyaninato complexes, i.e., [Fe(amine)2(pc)] 2 (amine = decan‐1‐amine) and 3 (amine = benzylamine), with the two new N‐donors occupying the trans‐axial positions. The new complexes were characterized by extensive NMR measurements in THF solution. For complex 3 with the benzylamine ligand, the solid‐state structure was determined by X‐ray diffraction methods. Complex 2 is sufficiently labile in THF solution to exchange one amine ligand against CO (gas) affording an equilibrium mixture containing [Fe(amine)(CO)(pc)] 4.
Chiral Phosphino‐ and (Phosphinooxy)‐Substituted N‐Heterocyclic Carbene Ligands and Their Application in Iridium‐Catalyzed Asymmetric Hydrogenation
Authors: Nanchen Steve , Pfaltz Andreas 
Published: August 2006

AbstractEnantiomerically pure iridium complexes with phosphino‐ and (phosphinooxy)‐substituted N‐heterocyclic carbene (NHC) ligands were synthesized. Investigation of their electronic properties showed a similar trans influence of the phosphino (or phosphinooxy) and the NHC units. The complexes were tested in iridium‐catalyzed hydrogenation. While low conversions were observed with unfunctionalized olefins, the catalysts proved to be suitable for hydrogenation of the α,β‐unsaturated ester 20, allylic alcohol 21, and imine 22. The enantioselectivities were, however, moderate.
Ab initio Emulsion Polymerization by RAFT (Reversible Addition–Fragmentation Chain Transfer) through the Addition of Cyclodextrins
Authors: Apostolovic Bojana , Quattrini Francesca , Butté Alessandro , Storti Giuseppe , Morbidelli Massimo 
Published: August 2006

AbstractA novel process to produce homo‐ and copolymers by RAFT polymerization in emulsion is presented. It is known that RAFT‐controlled radical polymerization can be conducted in emulsion polymerization without disturbing the radical segregation characteristic of this process, thus leading to polymerization rates identical to those encountered in the corresponding nonliving systems. However, RAFT agents are often characterized by very low water solubility and, therefore, they diffuse very slowly from the monomer droplets, where they are initially solubilized, to the reaction loci, i.e., the polymer particles. Accordingly, when used in emulsion polymerization, they are practically excluded from the reaction. In this work, we show that cyclodextrins, well‐known for their ability to form water‐soluble complexes with hydrophobic molecules, facilitate the transport across the H2O phase of the RAFT agent to the polymer particles. Accordingly, chains grow through the entire process in a controlled way. This leads to the production of low‐polydispersity polymers with well‐defined structure and end functionalities as well as to the possibility of synthesizing block copolymers by a radical mechanism.
Insertion Reactions of 1,2‐Disubstituted Olefins with an α‐Diimine Palladium(II) Complex
Authors: Carfagna Carla , Gatti Giuseppe , Mosca Luca , Paoli Paola , Guerri Annalisa 
Published: August 2006

AbstractThe migratory insertions of cis or trans olefins CH(X)CH(Me) (X = Ph, Br, or Et) into the metal–acyl bond of the complex [Pd(Me)(CO)(iPr2dab)]+ [B{3,5‐(CF3)2C6H3}4]− (1) (iPr2dab = 1,4‐diisopropyl‐1,4‐diazabuta‐1,3‐diene = N,N′‐(ethane‐1,2‐diylidene)bis[1‐methylethanamine]) are described (Scheme 1). The resulting five‐membered palladacycles were characterized by NMR spectroscopy and X‐ray analysis. Experimental data reveal some important aspects concerning the regio‐ and stereochemistry of the insertion process. In particular, the presence of a Ph or Br substituent at the alkene leads to the formation of highly regiospecific products. Moreover, in all cases, the geometry of the substituents in the formed palladacycle was the same as in the starting olefin, as a consequence of a cis addition of the Pd–acyl fragment to the CC bond. Reaction with CO and MeOH of the five‐membered complex derived from trans‐β‐methylstyrene (= [(1E)‐prop‐1‐enyl]benzene) insertion, yielded the 2,3‐substituted γ‐keto ester 9 with an (2RS,3SR)‐configuration (Scheme 3).
Synthesis of 3‐Acyl‐4‐alkenylpyrrolidines by Platinum‐Catalyzed Hydrative Cyclization of Allenynes
Authors: Matsuda Takanori , Kadowaki Sho , Murakami Masahiro 
Published: August 2006

AbstractA series of nitrogen‐tethered allenynes (‘5‐aza‐1,2‐dien‐7‐ynes’) 1 were transformed to the corresponding 3‐acyl‐4‐alkenylpyrrolidines 3 when treated with a catalytic amount of PtCl2 in MeOH at 70°. Initial Pt‐promoted cyclization forms a nonclassical carbocationic intermediate. In contrast to the cycloisomerization in toluene, which produced the bicyclic cyclobutenes 2, the intermediate is intercepted by addition of an oxygen nucleophile to achieve the formal hydrative cyclization.
Statistical Approach for the Determination of the Stereoregularity of Optically Active Propylene–CO Copolymers
Authors: Bronco Simona 
Published: August 2006

AbstractA two‐parameter statistic model was applied to analyze the NMR spectra of a series of stereoregular propylene–CO copolymers synthesized by catalytic polymerization in the presence of various transition‐metal complexes containing chiral ligands. The concentration of the different pentads, estimated to be recognizable in the spectra, was determined. A tentative assignment of the nature of the different peaks composing the signal of the CO group in the 13C‐NMR spectra is proposed.
Influence of bone quality on the strength of internal and external fixation of tibial plateau fractures
Authors: Ali Ahmad M. , Saleh Michael , Eastell Richard , Wigderowitz Carlos A. , Rigby Alan S. , Yang Lang 
Published: August 2006

AbstractWe studied the influence of different parameters of bone quality on the fixation strength of bicondylar tibial plateau fractures and examined the relationship between these parameters. Bone quality was measured in the plateau of 16 cadaveric tibias using three modalities: dual‐energy X‐ray absorptiometry (DXA), peripheral quantitative computer tomography (pQCT), and spectral analysis of digitized radiographs (SADR). The tibias were divided into two groups by the median bone mineral density (BMD) and randomized to receive either dual plating or external fixator for the stabilization of a standardized bicondylar tibial fracture. The fixed fractures were subjected to axial compression until failure. DXA BMD correlated most significantly with the failure load (r ≥ 0.79, p < 0.001), followed by the pQCT parameters of cancellous bone (0.52 ≥ r ≥ 0.73, p < 0.01). Similar strong correlations were also evident in both fixation methods. For parameters derived from SADR, only those including both longitudinal and transverse trabecular orientations had modest correlation with the fixation strength (0.53 ≥ r ≥ 0.71, p < 0.01). The failure loads of the two fixation techniques were not significantly different (mean ± SD = 3522 ± 1386 N and 3710 ± 1356 N, respectively, p = 0.78). However, BMD in the dual‐plating group influenced the failure load significantly (p = 0.03), whereas in the external fixation group this was less evident (p = 0.100). The majority of bone quality parameters that correlated with fixation strength were also strongly correlated with each other, particularly the BMDs measured by DXA and pQCT. This is the first study that relates fixation strength of bicondylar tibial plateau fractures to bone quality assessed at the same anatomical site. BMD around the fracture site had the best correlation with the failure load regardless of the fixation technique. The two fixation methods tested performed equally well, and the choice between them depends on the soft tissue condition and surgeon preference. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:2080–2086, 2006
Effect of naringin on bone cells
Authors: Wong R.W.K. , Rabie A.B.M. 
Published: August 2006

AbstractStatin, a HMG‐CoA reductase inhibitor, was shown to increase BMP‐2 gene expression for bone formation, by blocking the mevalonate pathway in cholesterol production. We investigated the effect of naringin, a flavonoid available commonly in citrus fruits, which was also a HMG‐CoA reductase inhibitor, in UMR 106 osteoblastic cell line in vitro. The control group consisted of cells cultured without any intervention for different time intervals (24 h, 48 h, and 72 h), whereas the experimental (naringin) group consisted of cells cultured with naringin of different concentrations (0.001 µmol/L, 0.01 µmol/L, and 0.1 µmol/L) for the same time intervals of the control. Colorimetric Tetrazolium (MTT) assay, total protein content assay, and alkaline phosphatase activity were used to measure the cellular activities. Results for the naringin group showed an increase in MTT assay compared with the control and the effect was dose dependent. At high concentration (0.1 µmol), the increases ranged from 60% to 80%. In the total protein content assay, naringin also showed an increase compared with control and the effect was also dose dependent. At high concentration (0.1 µmol), the increases ranged from 9% to 20%. In the alkaline phosphatase activity assay, naringin at high concentration (0.1 µmol) significantly increased the activity up to 20%. In conclusion, naringin significantly increased bone cell activities in vitro. This is the first study specifically attempted to investigate the effect of naringin on bone cell activities. Besides statin, this provided another example of mevalonate pathway blockage in the cholesterol production pathway by HMG‐CoA reductase inhibition will increase the bone cell activities. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:2045–2050, 2006