bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient Transfer Hydrogenation Using Iridium and Rhodium Complexes of Benzannulated N‐Heterocyclic Carbenes
Authors: Türkmen Hayati , Pape Tania , Hahn F. Ekkehardt , Çetinkaya Bekir 
Published: October 2008

AbstractBenzimidazol‐2‐ylidene(NHC) derivatives of iridium(I) and rhodium(I) bearing electron‐rich and/or functional substituents R and R′ at the nitrogen atoms of the heterocycle [IrBr(cod)(NHC)] (a) or [RhBr(cod)(NHC)] (b) (R = 2,3,5,6‐tetramethylbenzyl; R′ = methoxyethyl, 1a,b; R = R′ = 2,3,5,6‐tetramethylbenzyl, 2a,b; R = pentamethylbenzyl, R′ =methoxyethyl, 3a,b; R = R′ = pentamethylbenzyl, 4a,b) were prepared. All compounds were fully characterized by 1H and 13C NMR spectroscopy, mass spectrometry (MALDI), and elemental analysis. In addition, the molecular structures of 1a, 2a, and 3a were determined by single‐crystal X‐ray diffraction studies. All of the new benzimidazol‐2‐ylidene iridium(I) and rhodium(I) complexes were found to be effective catalysts for transfer hydrogenation with iridium(I) derivative 1a showing the highest catalytic activity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Modification of Glassy Carbon Electrode With Single‐Walled Carbon Nanotubes and α‐Silicomolybdate: Application to Sb(III) Detection
Authors: Salimi Abdollah , Korani Aazam , Hallaj Rahman , Khoshnavazi Roshan 
Published: October 2008

AbstractA simple procedure was developed to prepare a glassy carbon (GC) electrode modified with single‐walled carbon nanotubes (SWCNTs) and polyoxometalate. With immersing SWCNTs modified GC electrode in silicon polyoxomolybdate (α‐SiMo12O404−) solution (direct deposition) for a short period of time (2–10 s) oxoanion adsorbed strongly and irreversibly on SWCNTs. Cyclic voltammograms of the α‐SiMo12O404− incorporated‐SWCNTs indicates three well‐defined and reversible redox couples with surface confined characteristic at wide pH range (1–7). The surface coverage (Γ) of α‐SiMo12O404− immobilized on SWCNTs was 2.14 (±0.11)×10−9 mol cm−2 indicating high loading ability of SWCNTs for polyoxometalate. The charge transfer rate constant (ks) of three redox couples of adsorbed α‐SiMo12O404− were 9.20 (±0.20), 8.02 (±0.20), and 3.70 (±0.10) s−1, respectively, indicate great facilitation of the electron transfer between α‐SiMo12O404− and CNTs. In this research the attractive mechanical and electrical characteristics of CNTs and unique properties and reactivity of polyoxometalates were combined. The modified electrode in buffer solution containing Sb(III) shows a new redox system at 0.38 V in pH 1. The voltammetric peak current increased with increasing Sb(III) concentration. The differential pulse voltammetry (DPV) technique was used for detection micromolar concentration of antimony. Furthermore, the interference effects various electroactive compounds on voltammetric response of Sb(III) were negligible. Finally the ability of the modified electrode for antimony detection in real samples was evaluated.
A Contactless Impedance Probe for Simple and Rapid Determination of the Ratio of Liquids with Different Permittivities in Binary Mixtures
Authors: Opekar František , Štulík Karel , Fišarová Michaela 
Published: October 2008

AbstractSimple contactless cells with planar or tubular electrodes have been designed for measurement of the permittivity of solutions. The cells, connected to an integrated circuit of astable multivibrator, respond primarily to the capacitance component of the cell impedance, the multivibrator frequency depends in a defined manner on the solution permittivity and is readily used as the analytical signal in determinations of the ratios of components in binary liquid mixtures; water solution of methanol, ethanol and dioxane have been tested. The response of the cell with planar electrodes satisfies well the simple theoretical model and both the cells provide results with a sufficient sensitivity, a low LOD value (units of %vol) and a good precision (around 1%rel). The cell simplicity, small dimensions, long‐term stability and the possibility of powering them from a battery make them suitable for hand‐held meters. As an example of application in practice, the content of ethanol was determined in the car fuel petrol.
Preparation of GOD/Sol‐Gel Silica Film on Prussian Blue Modified Electrode for Glucose Biosensor Application
Authors: Liang Ru‐Ping , Jiang Jing‐Li , Qiu Jian‐Ding 
Published: October 2008

AbstractA novel amperometric glucose biosensor was fabricated by in situ incorporating glucose oxidase (GOD) within the sol‐gel silica film on a Prussian blue (PB) modified electrode. The method is simple and controllable, which combined the merits of in situ immobilizing biomolecules in sol‐gel silica film by electrochemical method and the synergic catalysis effects of PB and GOD molecules. Scanning electron microscopy (SEM) showed that the GOD/sol‐gel silica film was homogeneous with a large number of three‐dimensional nanopores, which not only enhanced mass transport, but also maintained the active configuration of the enzyme molecule and prevented the leakage of enzyme, therefore improved the stability and sensitivity of the biosensor. The fabricated biosensor showed fast response time (10 s), high sensitivity (26.6 mA cm−2 M−1), long‐term stability, good suppression of interference, and linear range of 0.01 mM–5.8 mM with a low detection limit of 0.94 μM for the detection of glucose. In addition, the biosensor was successfully applied to determine glucose in human serum samples.
Direct Electrochemistry of Hemoglobin on Single‐Walled Carbon Nanotubes Modified Carbon Ionic Liquid Electrode and Its Electrocatalysis
Authors: Sun Wei , Li Xiaoqing , Zhai Ziqin , Jiao Kui 
Published: October 2008

AbstractIn this article we report on the fabrication of a carbon ionic liquid electrode (CILE) by using a room temperature ionic liquid of 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) as binder. It was further modified by single‐walled carbon nanotubes (SWCNTs) to get a SWCNTs modified CILE denoted as SWCNTs/CILE. The redox protein of hemoglobin (Hb) was further immobilized on the surface of SWCNTs/CILE with the help of Nafion film. UV‐vis and FT‐IR spectra indicated that the immobilized Hb retained its native conformation in the composite film. The direct electrochemistry of Hb on the SWCNTs/CILE was carefully studied in pH 7.0 phosphate buffer solution (PBS). Cyclic voltammetric results indicated that a pair of well‐defined and quasireversible voltammetric peaks of Hb heme Fe(III)/Fe(II) was obtained with the formal potential (E°') at −0.306 V (vs. SCE). The electrochemical parameters such as the electron transfer coefficient (α), the electron transfer number (n) and the apparent heterogeneous electron transfer rate constant (ks) were calculated as 0.34, 0.989 and 0.538 s−1, respectively. The fabricated Hb modified electrode showed good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) in the concentration range from 20.0 to 150.0 mmol/L with the detection limit of 10.0 mmol/L (3σ).
Performance comparison of filters with different aggregates
Authors: Zhang L. , Scholz M. 
Published: October 2008

AbstractUnplanted upflow filters, which were filled with different filter media (natural zeolite, blast furnace granulated slag, ceramsite, and walnut shells), were operated to assess their nutrient removal performances. Different preprocessing methods involving aerobic and anaerobic sludges were applied to the filters to accelerate the treatment processes. The results indicated that preprocessing enhanced the soluble chemical oxygen demand (SCOD) removal, but had no obvious influence on the total nitrogen (TN) and total phosphorus (TP) removal efficiencies. Filters containing blast furnace granulated slag were independent with respect to SCOD loading rate variations in the range between 100 and 900 mg/d. A linear velocity equation was used to determine the nutrient removal velocities of blast furnace granulated slag‐filled filters. The removal velocities were rapid, and highest for TP and lowest for TN. Compared with other filters, blast furnace granulated slag‐filled filters performed best concerning nutrient removal and retention. Walnut shell‐filled filters performed worst. © 2008 American Institute of Chemical Engineers Environ Prog, 2009
Synthesis of Derivatives of the Optically Active β‐Amino Acids from (+)‐Car‐2‐ene
Authors: Koneva Ekaterina A. , Volcho Konstantin P. , Gatilov Yuri V. , Korchagina Dina V. , Salnikov Georgi E. , Salakhutdinov Nariman F. 
Published: October 2008

AbstractThe reaction of (+)‐car‐2‐ene (4) with chlorosulfonyl isocyanate (=sulfuryl chloride isocyanate; ClSO2NCO) led to the tricyclic lactams 6 and 8 corresponding to the initial formation both of the tertiary carbenium and α‐cyclopropylcarbenium ions (Scheme 2). A number of optically active derivatives of β‐amino acids which are promising compounds for further use in asymmetric synthesis were synthesized from the lactams (see 16, 17, and 19–21 in Scheme 3).
Monohydroxy‐Substituted Polyunsaturated Fatty Acids from Swertia japonica
Authors: Kikuchi Masafumi , Yaoita Yasunori , Kikuchi Masao 
Published: October 2008

AbstractFourteen monohydroxy‐substituted polyunsaturated fatty acids, including two new compounds, (9Z,12S,13E,15Z)‐12‐hydroxyoctadeca‐9,13,15‐trienoic acid (10) and (9Z,12Z,14E,16R)‐16‐hydroxyoctadeca‐9,12,14‐trienoic acid (13), and 12 known ones, i.e., 1–9, 11, 12, and 14, were isolated from the whole plants of Swertia japonica Makino, and characterized as the corresponding methyl esters 1a–14a. Their structures were elucidated by analysis of the corresponding spectroscopic data, and the absolute configurations of 10a and 13a were determined by the Mosher‐ester method. The CD spectra (Table) of compounds 1a–14a are briefly discussed. This is the first report on the isolation of monohydroxy‐substituted polyunsaturated fatty acids from the Swertia genus in Gentianaceae.
Dioxopiperazine Alkaloids Produced by the Marine Mangrove Derived Endophytic Fungus Eurotium rubrum
Authors: Li Dong‐Li , Li Xiao‐Ming , Li Tie‐Gang , Dang Hong‐Yue , Wang Bin‐Gui 
Published: October 2008

AbstractCultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of stems of the mangrove plant Hibiscus tiliaceus, resulted in the isolation of two new dioxopiperazine derivatives, namely, dehydrovariecolorin L (1) and dehydroechinulin (2), together with eight known dioxopiperazine compounds including variecolorin L (3), echinulin (4), isoechinulin A (5), dihydroxyisoechinulin A (6), preechinulin (7), neoechinulin A (8), neoechinulin E (9), and cryptoechinuline D (10). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature. Compounds 1, 2, 9, and 10 were investigated for their α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical‐scavenging activity. In addition, the new compounds, 1 and 2, were evaluated for their cytotoxic activity against the P‐388, HL‐60, and A549 cell lines.
Four New Compounds from Sinacalia tangutica
Authors: Zhu Ying , Zhao Yan , Huang Guo‐Du , Wu Wang‐Suo 
Published: October 2008

AbstractFour new compounds, 9α‐hydroxy‐1β‐methoxycaryolanol (1), stigmast‐5‐ene‐7α,22α‐diol‐3β‐tetradecanoate (2), 7‐O‐(6′‐acetoxy‐β‐D‐glucopyranosyl)coumarin (3), and 8‐O‐(6′‐acetoxy‐β‐D‐glucopyranosyl)‐7‐hydroxycoumarin (4), together with ten known compounds, were isolated from the aerial parts of Sinacalia tangutica. The structures of the new compounds were established by means of extensive spectroscopic analyses (1D‐ and 2D‐NMR, EI‐MS, HR‐ESI‐MS, as well as IR and UV) and by comparison of their spectroscopic data with those of structurally related compounds reported in the literature.
Competitive Intramolecular Aryl‐ and Alkyl‐CH Bond Activation and Ligand Evaporation from Gaseous Bisimino Complexes [Pt(L)(CH3)((CH3)2S)]+ (L=C6H5NC(CH3)C(CH3)NC6H5)
Authors: Butschke Burkhard , Schlangen Maria , Schröder Detlef , Schwarz Helmut 
Published: October 2008

AbstractMechanistic details for the formation of methane from the title compound as well as the combined elimination of (CH3)2S/CH4 are derived from various mass‐spectrometric experiments including deuterium‐labeling studies and DFT calculations. For the first process, i.e., methane formation, we have identified three competing pathways in which the intact, Pt‐bonded methyl group combines with a H‐atom that originates from a phenyl substituent (ca. 7%), the dimethyl sulfide ligand (ca. 41%), and a methyl group of the diazabutadiene backbone (ca. 52%). In contrast, in the combined (CH3)2S/CH4 elimination, the methane is specifically formed from the Pt‐bound CH3 group and a H‐atom provided by one of the phenyl groups (‘cyclometalation’).
Synthesis and Selected Transformations of 1H‐Imidazole 3‐Oxides Derived from Amino Acid Esters
Authors: Jasiński Marcin , Mlostoń Grzegorz , Linden Anthony , Heimgartner Heinz 
Published: October 2008

AbstractA series of new optically active 1H‐imidazole 3‐oxides 5 with a substituted acetate group at N(1) as the chiral unit were prepared by the reaction of α‐(hydroxyimino) ketones, α‐amino acid methyl esters, and formaldehyde. In an analogous reaction, ethyl 2‐(hydroxyimino)‐3‐oxobutyrate and 1,3,5‐trialkylhexahydro‐1,3,5‐triazines gave 3‐oxido‐1H‐imidazole‐4‐carboxylates 14, which easily rearranged into the 2‐oxo derivatives 15. Selected examples of N‐oxides 5 could be transformed into the corresponding 2,3‐dihydro‐1H‐imidazole‐2‐thione derivatives 10 via a ‘sulfur‐transfer reaction’, and the reduction of the histidine derivative 5i with Raney‐Ni yielded the optically active 2,3‐bis(imidazolyl)propanoate 12. Furthermore, reaction of the (1H‐imidazol‐1‐yl)acetates with primary amines yielded the corresponding acetamides.
Rhodium Fluoroapatite Catalyzed Conjugate Addition of Arylboronic Acids to α,β‐Unsaturated Carbonyl Compounds
Authors: Kantam Mannepalli Lakshmi , Subrahmanyam Vura Bala , Shiva Kumar Kota Balaji , Venkanna Gopaladasu T. , Sreedhar Bojja 
Published: October 2008

AbstractRhodium fluoroapatite (RhFAP) is an efficient catalyst for conjugate addition of organoboron reagents to α,β‐unsaturated carbonyl compounds. A variety of arylboronic acids and α,β‐unsaturated carbonyl compounds were converted to the corresponding conjugate‐addition products, demonstrating the versatility of the reaction. The reaction is highly selective. RhFAP was recovered quantitatively by simple filtration, and reused for four cycles.
Two New C20‐Diterpenoid Alkaloids from the Tibetan Medicinal Plant Aconitum naviculareStapf
Authors: Cao Jin‐Xin , Li Liang‐Bo , Ren Jie , Jiang Si‐Ping , Tian Ren‐Rong , Chen Xu‐Lin , Peng Shu‐Lin , Zhang Jie , Zhu Hua‐Jie 
Published: October 2008

AbstractTwo new C20‐diterpenoid alkaloids named naviculine A (1) and naviculine B (2), were isolated from Aconitum naviculare Stapf. Their structures were established by spectral methods, especially 2D‐NMR spectra (1H,1H‐COSY, HMQC, HMBC, and NOESY) and DFT methods (at the B3LYP/6‐311++G(2d,p)//B3LYP/6‐31G(d) level), respectively. They were assayed for their anti‐HIV‐1 activity.
A Concise Synthesis of the DNA‐Intercalating and Antimalarial Alkaloid Cryptolepine and Its Fluorescence Behaviour in Solvents of Different Polarities
Authors: Lai Tapan Kumar , Chatterjee Asima , Banerji Julie , Sarkar Deboleena , Chattopadhyay Nitin 
Published: October 2008

AbstractA microwave‐induced rapid and facile synthesis of the DNA‐intercalating and antimalarial drug cryptolepine is described. The key step in this synthesis involves the aqueous‐phase base‐catalyzed condensation of isatin and 1‐acetyl‐1H‐indol‐3‐yl acetate which has been simplified and expedited by dielectric heating, employing an ordinary domestic microwave oven. The method transforms the synthesis of an important drug molecule from a prohibitively lengthy process to a matter of a few minutes with a much improved yield. Dual absorption and fluorescence is observed from the molecular system in solvents of different polarity thus providing valuable insight into its binding modes toward protein or DNA.
Two New Phenylpropanoid Derivatives from Codonopsis tangshenOliv.
Authors: Song Dan , Chou Gui‐Xin , Zhong Guo‐Yue , Wang Zheng‐Tao 
Published: October 2008

AbstractTwo new 3‐hydroxy‐3‐methylglutaric acid derived phenylpropanoid glucosides, tangshenoside V (1) and tangshenoside VI (2), were isolated from the roots of Codonopsis tangshen Oliv., along with the two known compounds tangshenoside I (3) and tangshenoside III (4). Their structures were elucidated by spectroscopic methods (IR and 1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS).
The effect of different powder particle size on mechanical properties of sintered alumina, resin‐ and glass‐infused alumina
Authors: Chaiyabutr Yada , Giordano Russell , Pober Richard 
Published: October 2008

AbstractIn this study, the compaction and sintering behavior of fine alumina powders of different particle sizes and the effect of matrix particle size on biaxial strength and fracture toughness of infused matrices were investigated. Three different alumina powders, In‐Ceram alumina, A16SG, and RC172 were selected, representing a range of particle size and shape. RC172 and A16SG were dry‐pressed. In‐Ceram alumina was slip‐cast following manufacturer's recommendations. Dry‐pressed ceramic blocks were sectioned into disks with a thickness of 1.5‐mm. Uninfused disks were sintered at four temperatures between 1250°C and 1400°C. For glass or resin infused specimens, alumina disks were sintered at 1250°C for 2 h and separated into two groups for glass infusion and resin (UDMA/TEGDMA) infusion. Disks were tested for biaxial flexural strength with a universal testing machine (Instron) at 0.5‐mm/min crosshead speeds. One‐way ANOVA and Duncan's multiple range tests revealed that alumina disks with different smaller particle sizes have significantly higher biaxial strength (p< 0.05). The strength of the alumina matrix was greatly increased by glass and resin infusion. The biaxial strength of resin‐infused alumina increased as particle size decreased, whereas strength of glass‐infused alumina was constant. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Preparing for inspection: Managing regulations and practices surrounding donors with positive infectious disease testing
Authors: Ferschke Jillian 
Published: October 2008

AbstractFederal and local regulatory agencies mandate that all blood collection facilities test each allogeneic blood donation for evidence of infectious diseases. When a donation tests positive or reactive for any of the required screening tests, facilities are required to take appropriate action by deferring donors and removing potentially infectious products from inventory. Each required action must be performed in accordance with posted regulations and documented for record retention. Donor deferral records related to positive or reactive infectious disease testing are particularly vulnerable targets of inspection. There are currently numerous regulations and requirements for handling donors who test positive or reactive in infectious disease screening tests. Each of these regulations must be somehow organized and incorporated into written departmental procedures for staff to follow with confidence and accuracy. UMass Memorial Medical Center has implemented a process that equips staff members with the knowledge and confidence to respond in an organized way to an inspection of donor deferral records and related activities. The extraction of regulatory detail from written procedures into job aids and tools for staff to follow with ease and confidence ensures an inspection with zero findings in this area. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Therapeutic apheresis in neurological disorders: A survey of the evidence in support of current category I and II indications for therapeutic plasma exchange
Authors: Weinstein Robert 
Published: October 2008

AbstractNeurologic disorders constitute the largest group of indications for therapeutic plasma exchange. Although some of the traditional indications are supported by properly designed randomized trials, others are not. This article provides a critical look at the evidence in support of the assignment by ASFA of Category I or II indications to neurologic disorders in its most recent (2007) evaluation of therapeutic apheresis. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Kinetic study of the reactions of p‐nitrophenyl acetate and p‐nitrophenyl benzoate with oximate nucleophiles
Authors: Tiwari Shuchi , Kolay Sancheeta , Ghosh Kallol K. , Kuca Kamil , Marek Jan 
Published: October 2008

AbstractThe reactions of p‐nitrophenyl acetate (PNPA) and p‐nitrophenyl benzoate (PNPB) with α‐nucleophile oximates, that is, butane 2,3‐dione monoximate, pralidoximate, and other oximates have been studied in the presence of different cationic surfactants. The first‐order rate constant increases with increasing surfactant concentration. The extent of acceleration is dependent on the head group structure of surfactants. The PNPA is more reactive than PNPB toward all the nucleophiles at higher concentration of surfactants. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 57–64, 2009
Kinetics and mechanism of the oxidation of some organic sulfides by morpholinium chlorochromate
Authors: Malani Neha , Baghmar Manju , Sharma Pradeep K. 
Published: October 2008

AbstractThe oxidation of organic sulfides by morpholinium chlorochromate (MCC) resulted in the formation of the corresponding sulfoxides. The reaction is first order with respect to both MCC and the sulfide. The reaction is catalyzed by toluene‐p‐sulfonic acid (TsOH). The oxidation was studied in 19 different organic solvents. An analysis of the solvent effect by Swain's equation showed that both the cation‐ and anion‐solvating powers of the solvents play important roles. The correlation analyses of the rate of oxidation of 34 sulfides were performed in terms of various single and multiparametric equations. For the aryl methyl sulfides, the best correlation is obtained with Charton's localized‐delocalized‐resonance and localized‐delocalized‐resonance‐steric equations. The oxidation of alkyl phenyl sulfides exhibited a very good correlation in terms of the Pavelich–Taft equation. The polar reaction constants are negative, indicating an electron‐deficient sulfur center in the rate‐determining step. A mechanism involving formation of a sulfonium cation intermediate in the slow step has been proposed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 65–72, 2009
Lasermaterialbearbeitung aus der Ferne
Authors: Badyukov Dmitry , Koch Jürgen , Kemmel Matthias 
Published: October 2008

AbstractNeuesten Trends der Strahlquellenanbieter hin zu brillanten Lasersystemen mit fasergekoppelten Scheiben‐ oder Faserlasern folgend, wurde ein robotergeführter, f‐theta‐freier Scann‐Kopf zur dreidimensionalen Strahlablenkung, der zur Zeit im sogenannten Remote‐Laserstrahlschweißen eingesetzt wird, entwickelt. In diesem Artikel gehen wir auf die besondere Auslegung der Optik mit der Fokussiereinrichtung vor den Ablenkspiegeln ein, welche zu einem f‐theta‐freien System führt, erläutern die Vorteile eines solchen Aufbaus gegenüber der konventionellen Technik mit Fokussierlinse nach den Ablenkspiegeln und zeigen mit Hilfe von Schweißnahtanalysen die Qualität der Schweißungen auf. Anhand der im Automobilbau eingesetzten Stahlwerkstoffe soll der interessierte Leser zur Entwicklung weiterer Applikationen für Remote‐Systeme animiert werden. Abschließend werden wir unsere Vision für Remote‐Anlagen insbesondere beim Laserschneiden darlegen.