bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of the Separation of Quinolines in Micellar Liquid Chromatography by Experimental Design and Regression Models
Authors: HADJMOHAMMADI M. R. , KAMEL K. 
Published: December 2008

AbstractThe chemometrics approach was applied to the optimization of separation of quinolines in micellar liquid chromatography (MLC). The effect of four experimental parameters on chromatographic retention time was investigated by means of multivariate analysis. The factors considered were the concentration of sodium dodecyl sulfate (SDS), the organic modifier concentration and the length of its alkyl chain, and pH of the mobile phase. The experiments were performed according to a face centered cube response surface experimental design. In order to optimize the separation a Pareto‐optimality method was employed. The models were verified, because a good agreement was observed between the predicted and experimental values of the chromatographic response function in the optimal condition. The obtained regression models were characterized by both descriptive and predictive ability
(R2≥0.97 and RCV2≥0.92) and allowed the chromatographic separation of the quinolines with a good resolution and a total analysis time of 50 min.
Ferric Perchlorate Catalyzed One‐pot Synthesis of 1,2,3,4‐Tetrahydro‐2‐pyrimidinones and ‐thiones: an Expedient Protocol for the Biginelli Reaction
Authors: HERAVI Majid Momahed , BEHBAHANI Farahnaz Kargar , OSKOOIE Hossien Abdi 
Published: December 2008

AbstractAn efficient synthesis of 1,2,3,4‐tetrahydro‐2‐pyrimidinones and ‐thiones using ferric perchlorate as the catalyst from an aldehyde, ethyl acetoacetate, and urea or thiourea in acetonitrile was described. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of full catalysis, good yields and short reaction time.
A Facile Aqueous Synthesis of Bis(indol‐3‐yl)alkanes Catalyzed by Dodecylbenzenesulfonic Acid
Authors: PENG Yi‐Yuan , ZHANG Qiu‐Lan , YUAN Jian‐Jun , CHENG Jin‐Pei 
Published: December 2008

AbstractAn environmentally friendly synthetic method for bis(indol‐3‐yl)alkane derivatives has been developed. In the presence of 10 mol% of dodecylbenzenesulfonic acid (DBSA), electrophilic substitution reaction of indoles with aldehydes or ketones proceeded smoothly in water, giving rise to the corresponding bis(indol‐3‐yl)alkanes in good to excellent yields. The use of inexpensive and easily available catalyst, mild reaction conditions and simple work‐up procedure made this protocol practical and economically attractive.
A Novel Practical Synthesis of Phenanthrenes Using Iron(III) Chloride Involved Intramolecular Oxidative Coupling at Room Temperature
Authors: LÜ Mao‐Yun , WANG Kai‐Liang , CAI Fei , WANG Hai‐Ying , WANG Qing‐Min 
Published: December 2008

AbstractIron(III) chloride has been used to prepare the polymethoxy substituted phenanthrene derivatives via intramolecular oxidative coupling of (E or Z)‐2,3‐di(substituted phenyl)acrylate at room temperature in excellent yields. Mild reaction conditions and the use of inexpensive and nontoxic FeCl3 provide a novel practical and large‐scaled viable route for the synthesis of the important phenanthrene rings.
Biomimetic Synthesis of Twenty‐four Long‐chained Diketones as Precursors for Muscone and Further Macrocyclic Ketones
Authors: GUO Yuan , CHEN Kang‐Yu , LI Jian‐Li , SHI Zhen 
Published: December 2008

AbstractThe one‐carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. Bisbenzimidazolium salts were used as a tetrahydrofolate coenzyme model, and thus the biomimetic synthesis of twenty‐four acyclic diketones as precursors for macrocyclic ketones was successfully accomplished by using the addition‐hydrolysis reaction of the bisbenzimidazolium salts with alkyl magnesium halide, wherein six diketones have not been reported in literature. Accordingly, a short route to muscone analogues was provided.
Nitration of Substituted Benzenes Catalyzed by Metal Bis[(perfluoroalkyl)sulfonyl]imides in Quaternary Ammonium Ionic Liquids
Authors: WANG Shuo‐Jin , SUN Zhi‐Ying , NIE Jin 
Published: December 2008

AbstractThe nitrations of substituted benzenes proceeded rapidly and cleanly with very good yields in Cu(N(C4F9SO2)2)2/ [N4446][Tf2N] or In(NTf2)3/[N4446][Tf2N] catalyst system, in which HNO3/Ac2O was used as the nitrating agent. For the nitration of chlorobenzene when 2 mol% catalyst was used at room temperature for 10 min, 87.6% and 90.6% of conversion of chlorobenzene were achieved, respectively and the para/ortho ratios of products were about 4.3–4.8. The catalyst systems with ionic liquid could be recovered easily and reused more than 5 times.
Mild and Efficient Catalytic Protocol for Tetrahydropyranylation of Alcohols Using Acidic Keggin and Wells‐Dawson Structures
Authors: TAYEBEE Reza 
Published: December 2008

AbstractA simple, mild and effective procedure is reported to the generation of 2‐tetrahydropyranyl acetals from alcohols. Keggin and Wells‐Dawson heteropolyoxometalates were used as catalysts at ambient temperature in acetone as solvent with good yields and high selectivities in a short reaction time. Different reaction parameters affecting efficiency of the protocol were also studied. The use of these acid catalysts allows replacing the usual soluble inorganic acids, contributing to waste reduction.
Therapy‐related acute myelogenous leukemia and myelodysplastic syndrome in patients with acute lymphoblastic leukemia treated with the hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone regimens
Authors: Verma Dushyant , O'Brien Susan , Thomas Deborah , Faderl Stefan , Koller Charles , Pierce Sherry , Kebriaei Partow , Garcia‐Manero Guillermo , Cortes Jorge , Kantarjian Hagop , Ravandi Farhad 
Published: December 2008

AbstractBACKGROUND:Secondary malignancies including myeloid neoplasms occur infrequently in acute lymphoblastic leukemia (ALL) and to the authors' knowledge have not been as well documented in adults as in children.METHODS:A total of 641 patients with de novo ALL who were treated with the hyper‐CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone) regimen or its variants were analyzed.RESULTS:Sixteen patients (2.49%) developed secondary acute myelogenous leukemia (AML) (6 patients) or myelodysplastic syndrome (MDS) (10 patients). At the time of ALL diagnosis, the median age was 53 years; cytogenetics were normal in 11 patients, pseudo‐diploidy with del(2) in 1 patient, t(9;22) in 1 patient, and unavailable in 3 patients. Frontline therapy included hyper‐CVAD in 7 patients, hyper‐CVAD with rituximab in 8 patients, and hyper‐CVAD with imatinib in 1 patient. Karyotype at time of AML/MDS diagnosis was −5, −7 in 9 patients, normal in 1 patient, complex in 1 patient, inv(11) in 1 patient, t(4;11) in 1 patient, del(20) in 1 patient, and unavailable in 2 patients. Secondary AML/MDS developed at a median of 32 months after ALL diagnosis. Cytarabine plus anthracycline–based treatment was given to 12 patients with AML and high‐risk MDS. One patient with MDS received arsenic trioxide, 1 received clofarabine, and 2 received decitabine. Response to treatment was complete remission in 3 patients, partial remission in 6 patients, and no response in 6 patients; 1 patient was untreated. Eight patients (1 with AML and 7 with MDS) underwent allogeneic stem cell transplantation, and all but 2 died at a median of 3 months (range, 0.5–11 months) after transplantation. The median overall survival after a diagnosis of secondary AML and MDS was 9.25 months (range, 1+ to 26+ months).CONCLUSIONS:Secondary AML and MDS occur infrequently in adult patients with de novo ALL treated with the hyper‐CVAD regimens, and response to therapy is poor. Cancer 2009. © 2008 American Cancer Society.
Static and dynamic convergence studies of a four‐noded membrane finite element with rotational degrees of freedom based on displacement superposition
Authors: Çalık Karaköse Ülkü H. , Askes Harm 
Published: December 2008

AbstractStatic and dynamic performance tests of a four‐noded quadrilateral isoparametric membrane finite element enriched with rotational degrees of freedom (DOF) are presented. The formulation is based on displacement superposition whereby the in‐plane displacements are decomposed additively into a regular, low‐order contribution (governed by the nodal in‐plane displacements) and a higher‐order contribution (governed by the nodal in‐plane rotations). The sensitivity of the element to element distortion and element aspect ratio is investigated. Comparisons with standard bilinear finite elements are made for static and dynamic loading case. It is demonstrated that the studied element exhibits an accuracy per DOF that is superior to the standard bilinear finite element. Copyright © 2008 John Wiley & Sons, Ltd.
Electrochemical Study of Dialcarb “Distillable” Room‐Temperature Ionic Liquids
Authors: Wang Huan , Zhao Chuan , Bhatt Anand I. , MacFarlane Douglas R. , Lu Jia‐Xing , Bond Alan M. 
Published: December 2008

AbstractElectrode‐dependent potential windows (see picture, GC=glassy carbon) are determined for five dialkylammonium carbamate (dialcarb) room‐temperature ionic liquids in a systematic study of their physical and electrochemical properties. The viscosity and conductivity of the dialcarb ionic liquids, which are “distillable” at low temperature, are comparable to those of some conventional room‐temperature ionic liquids.magnified imageThe physical and electrochemical properties of five “distillable” room‐temperature ionic liquids from the dialcarb family (dialkylammonium carbamates formed from CO2 and dialkyl amines) are systematically investigated. In particular dimethyl (DIMCARB), diethyl (DIECARB), dipropyl (DIPCARB), methylethyl (MEETCARB), and methylpropyl (MEPRCARB) carbamate ionic liquids are studied. The temperature dependence of the viscosity and conductivity of MEETCARB exhibit an Arrhenius‐type relationship. Except for DIPCARB, which has too high a resistance, a reference potential scale is available by using the IUPAC recommended redox system, that is the cobalticenium/cobaltocene (Cc+/Cc) process, which exhibits an ideal reversible voltammetric response. Oxidation of decamethylferrocene, but not ferrocene, also is ideal in DIMCARB, DIECARB, MEETCARB, and MEPRCARB. The magnitudes of the potential windows of the electrochemically viable dialcarbs are investigated and follow the order of glassy carbon>Au>Pt>Hg. Diffusion coefficients of Cc+, DmFc, and double‐layer capacitance values are compared in each dialcarb. Despite the considerable viscosity of the dialcarbs, steady‐state voltammetric behavior is achieved at a rotating disk electrode for rotation rates of 1000 rpm or higher.
Limiting Current in a Flowing‐Electrolyte‐Type Droplet Cell
Authors: Fushimi Koji , Yamamoto Shunsuke , Konno Hidetaka , Habazaki Hiroki 
Published: December 2008

AbstractTo the limit: Electrolyte flow accelerates the mass‐transfer process in a droplet cell (see picture). The limiting current in the cell is expressed as a sum of hydrodynamic and stagnant terms. The current derived from the latter term indicates that convective mass transfer in the cell would be changed dramatically at a significantly small volumetric flow rate.magnified imageConvective mass transfer in a flowing‐electrolyte‐type droplet cell (f‐DC) is investigated for quantitative analysis of an electrode process and precise electrofabrication of microstructures using this device. The limiting current in the f‐DC was expressed theoretically and its practical equation is investigated experimentally by cyclic voltammetry in solutions containing a redox mediator. The limiting‐current equation in the f‐DC derived experimentally could be expressed as a sum of hydrodynamic and stagnant terms. The current derived from the latter term of the f‐DC is ten times larger than that in a conventional stagnant cell, thus indicating that the convective mass transfer in the cell would be changed dramatically at a small volumetric flow rate.
Effects of litter‐overlapping on emotionality, stress response, and reproductive functions in male and female rats
Authors: Uriarte Natalia , Ferreira Annabel , Rosa Ximena F. , Lucion Aldo B. 
Published: December 2008

AbstractIn rats, mating at postpartum estrus and delayed dispersal of the young would result in the overlapping of two different‐age litters. As a consequence, newborn pups' early experience will include not only that acquired during the interaction with the mother and age‐matched littermates, but also with older siblings. As early‐life experience modulates rodents' brain function, behavior and reproduction, we aimed to assess how changes in the early environment provoked by the overlapping of litters would affect emotionality, stress response and reproductive functions of male and female pups during adulthood. Results showed that both male and female overlapped reared pups exhibited a reduced behavioral inhibition in the open field test during adulthood. In addition, overlapped reared adult females, but not males, showed a blunted corticosterone response to an acute stressor during diestrus and a reduction in sexual behavior. In summary, natural changes in early experience provoked by the overlapping of litters, long‐term modulate affective and reproductive behaviors, and the endocrine stress response in a sex dimorphic manner. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 51: 259–267, 2009
Classroom implications of recent research into literacy development: from predictors to assessment
Authors: Shapiro Laura R. , Hurry Jane , Masterson Jackie , Wydell Taeko N. , Doctor Estelle 
Published: December 2008

AbstractWe outline how research into predictors of literacy underpins the development of increasingly accurate and informative assessments. We report three studies that emphasize the crucial role of speech and auditory skills on literacy development throughout primary and secondary school. Our first study addresses the effects of early childhood middle ear infections, the potential consequences for speech processing difficulties and the impact on early literacy development. Our second study outlines how speech and auditory skills are crucially related to early literacy in normally developing readers, whereas other skills such as motor, memory and IQ are only indirectly related. Our third study outlines the on‐going impact of phonological awareness on reading and wider academic achievement in secondary‐school pupils. Finally, we outline how teachers can use the current research to inform them about which assessments to conduct, and how to interpret the results. Copyright © 2008 John Wiley & Sons, Ltd.
2‐Quinoxalinol Salen Copper Complexes for Oxidation of Aryl Methylenes
Authors: Wu Xianghong , Gorden Anne E. V. 
Published: December 2008

AbstractA copper(II) complex of the 2‐quinoxalinol salen ligand (salquCu) 1 has been tested for use in catalysis. Here, an optimized method for oxidation of aryl methylenes and its potential applications are described. In organic solvents, the yields obtained are higher than with other commonly used catalytic methods. Because this methods does not require high heat or increased pressure, this presents an opportunity for more environmentally friendly or “green” chemistry in a single‐phase system. Using this method, a key fragment of natural products Vitamin K1 and K2, 1,4‐naphthoquinone, can be easily synthesized from 1,2,3,4‐tetrahydronaphthalene in increased yield (65 %) as compared to established methods (30–40 % yield) that require higher temperatures and increased pressure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Phosphonium Coupling in the Direct Bond Formations of Tautomerizable Heterocycles via C–OH Bond Activation
Authors: Kang Fu‐An , Sui Zhihua , Murray William V. 
Published: December 2008

AbstractSince the original report in 2004, phosphonium coupling has emerged as a new, mild, efficient, chemoselective and versatile methodology for the direct C–C, C–N, C–O, and C–S bond formations of unactivated and unprotected tautomerizable heterocycles. Phosphonium coupling proceeds via C–OH bond activation of a tautomerizable heterocycle with a phosphonium salt (e.g., PyBroP), and subsequent functionalization with either a nucleophile through SNAr displacement or an organometallic through transition‐metal‐catalyzed cross‐coupling. As the first direct bond formation via C–OH bond activation, phosphonium coupling offers a powerful and practical methodology that features operational simplicity, functionality compatibility, and broad substrate scope. Its attractive protecting‐group‐free direct bond formation involving a domino multiple‐step process in a single step provides unique and facile access to many biologically important heterocycles including macromolecules with sensitive functionalities (e.g., DNA, RNA and PNA building blocks). Consequently, the discovery of phosphonium coupling has finally enabled a single‐step transformation in nucleoside chemistry, which has been an unsolved synthetic challenge in the past half‐century. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Versatile Synthesis of Annulated Carbazole Analogs Involving a Domino Reaction of Bromomethylindoles with Arenes/Heteroarenes
Authors: Dhayalan Vasudevan , Clement J. Arul , Jagan Radhakrishnan , Mohanakrishnan Arasambattu K. 
Published: December 2008

AbstractA ZnBr2‐mediated arylation of aryl/heteroaryl methyl bromides with arenes at 80 °C led to the formation of arylated products, which underwent subsequent 1,5‐sigmatropic rearrangement followed by electrocyclization and aromatization with loss of a diethylmalonate unit to afford the corresponding annulated products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Speciation of Arsenic under Dynamic Conditions
Authors: Ackermann J. , Vetterlein D. , Tanneberg H. , Neue H.‐U. , Mattusch J. , Jahn R. 
Published: December 2008

AbstractIn periodically flooded soils, reductive conditions can occur, which favor the dissolution of Fe (hydr)oxides. Fe (hydr)oxides such as goethite are important sorbents for arsenate (AsV), which is the dominant As species in soils under aerobic conditions. Hence, the dissolution of Fe (hydr)oxides under reductive conditions can result in the mobilization and reduction of AsV and, thus, in an increase in the bioavailability of arsenic. The temporal dynamics of these processes and possible re‐sorption or precipitation of arsenite (AsIII) formed are poorly understood. Under controlled laboratory conditions, the temporal change in the redox potential and arsenic speciation with time after a simulated flooding event in a quartz‐goethite organic matter substrate, spiked with AsV, was examined. During a period of 6 weeks, substrate solutions were sampled weekly using micro‐suction cups and analyzed for pH, AsIII and AsV, Fe, Mn and P concentrations. Redox potentials and matric potentials were determined in situ in the substrate‐bearing cylinders. The redox potential and the ratio between AsIII and AsV concentrations remained unchanged during the experiment without organic matter application. With organic matter applied, the redox potential decreased and the AsIII concentrations in the substrate solution increased while the total As concentrations in the substrate solution strongly decreased. An addition of goethite (1 g/kg) per se led to a decrease of the total As in the substrate solution (almost 50 %). In respect to the potential As availability for plants, and consequently, the transfer into the food chain, the results are difficult to evaluate. The lower the total As concentrations in the substrate solution, determined with decreasing redox potential, the least plant As uptake will occur. This effect may however be compensated by a shift of the molar P/AsV ratio in the solution in favor of AsV which is expected to increase the As uptake.
Bog Iron Ores and their Potential Role in Arsenic Dynamics: An Overview and a “Paleo Example”
Authors: Banning A. 
Published: December 2008

AbstractBog iron ores (BIOs), i.e. terrestrial accumulations of iron (Fe) minerals forming within the zone of groundwater oscillation, have been described in several regions in Germany and other countries. Since BIOs are composed of a variety of Fe minerals, primarily amorphous Fe hydroxides, they are likely to have an influence on the arsenic (As) dynamics of an area, as these minerals represent important natural As sources and sinks. In this study, mineralogical research results (XRD, microscopy) of altered BIOs of Tertiary age (“paleo” BIOs or PBIOs), occurring within Cretaceous sands in an area of North Rhine‐Westphalia, are briefly presented. Genesis and mineralogical evolution of the categorized five different types of PBIOs, along with hydrogeochemical data from the literature, are discussed and compared to studies describing Holocene BIOs from other areas. In doing so, striking similarities (depositional environment, substratum, Fe source and its transport, geochemical evolution, and mineralogy) became evident. Differences in mineralogical and chemical composition can be attributed to the longer period of oxidation that the PBIOs have undergone (Fe hydroxide “aging”). This process is still ongoing (most of the groundwaters in the area plot in the goethite stability field) and leads to a higher stability of the Fe phases and thus, a stronger As retention. The known impact of the PBIOs on the As budget of the study area (they represent the source for elevated As concentrations in soils) can be transferred to more recent environments fostering BIO formation. These are likely to be even more important As sinks – and sources – as they contain higher Fe concentrations, higher shares of potentially mobile As and highly variable redox conditions which might lead to an As output from the BIOs into groundwater, soils and plants. Therefore, BIOs and their potential role in As behaviour are not only of scientific, but also of public interest.
Treatment of Hexafluoroarsenate from Contaminated Water: A Case Study
Authors: Daus B. , Weiss H. , Bernhard K. , Hoffmann P. , Neu T. R. , von Tümpling W. , Wennrich R. 
Published: December 2008

AbstractWastewater from the crystal glass factory can contain arsenic as hexafluoroarsenate. On the basis of a case study, an optimized treatment procedure for a hexafluoroarsenate‐containing surface water is presented using a strong basic anion exchanger. To minimize the microbial activity by forming biofilms on the surface of the exchanger material, distinctive technical features were described on the basis of results from laboratory and pilot plant tests. Silver impregnation of the ion exchange material has been shown to be not suitable due to a decrease in capacity by surface covering. Pre‐filters appear to be an inexpensive and effective option to increase the lifespan of the filters. A volume of 15 m3 of contaminated water was cleaned up using 1 kg of ion exchange resin on site in 250 hours. The ion exchange process has shown to be capable of cleaning waters contaminated with hexafluoroarsenate.