bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can Electrophilicity Act as a Measure of the Redox Potential of First‐Row Transition Metal Ions?
Authors: Moens Jan , Roos Goedele , Jaque Pablo , De Proft Frank , Geerlings Paul 
Published: August 2007

AbstractPrevious contributions concerning the computational approach to redox chemistry have made use of thermodynamic cycles and Car–Parrinello molecular dynamics simulations to obtain accurate redox potential values, whereas this article adopts a conceptual density functional theory (DFT) approach. Conceptual DFT descriptors have found widespread use in the study of thermodynamic and kinetic aspects of a variety of organic and inorganic reactions. However, redox reactions have not received much attention until now. In this contribution, we prove the usefulness of global and local electrophilicity descriptors for the prediction of the redox characteristics of first row transition metal ions (from Sc3+|Sc2+ to Cu3+|Cu2+) and introduce a scaled definition of the electrophilicity based on the number of electrons an electrophile ideally accepts. This scaled electrophilicity concept acts as a good quantitative estimate of the redox potential. We also identify the first solvation sphere together with the metal ion as the primary active region during the electron uptake process, whereas the second solvation sphere functions as a non‐reactive continuum region.
Preparation of N‐Sulfonyl‐ and N‐Carbonyl‐11‐Azaartemisinins with Greatly Enhanced Thermal Stabilities: in vitro Antimalarial Activities
Authors: Haynes Richard K. , Wong Ho‐Ning , Lee Kin‐Wo , Lung Chung‐Man , Shek Lai Yung , Williams Ian D. , Croft Simon L. , Vivas Livia , Rattray Lauren , Stewart Lindsay , Wong Vincent K. W. , Ko Ben C. B. 
Published: September 2007

AbstractAs the clinically used artemisinins do not withstand the thermal stress testing required to evaluate shelf life for storage in tropical countries where malaria is prevalent, there is a need to develop thermally more robust artemisinin derivatives. Herein we describe the attachment of electron‐withdrawing arene‐ and alkanesulfonyl and ‐carbonyl groups to the nitrogen atom of the readily accessible Ziffer 11‐azaartemisinin to provide the corresponding N‐sulfonyl‐ and ‐carbonylazaartemisinins. Two acylurea analogues were also prepared by treatment of the 11‐azaartemisinin with arylisocyanates. Several of the N‐sulfonylazaartemisinins have melting points above 200 °C and possess substantially greater thermal stabilities than the artemisinins in current clinical use, with the antimalarial activities of several of the arylsulfonyl derivatives being similar to that of artesunate against the drug‐sensitive 3D7 clone of the NF54 isolate and the multidrug‐resistant K1 strain of P. falciparum. The compounds possess relatively low cytotoxicities. The carbonyl derivatives are less crystalline than the N‐sulfonyl derivatives, but are generally more active as antimalarials. The N‐nitroarylcarbonyl and arylurea derivatives possess sub‐ng ml−1 activities. Although several of the azaartemisinins possess log P values below 3.5, the compounds have poor aqueous solubility (<1 mg L−1 at pH 7). The greatly enhanced thermal stability of our artemisinins suggests that strategic incorporation of electron‐withdrawing polar groups into both new artemisinin derivatives and totally synthetic trioxanes or trioxolanes may assist in the generation of practical new antimalarial drugs which will be stable to storage conditions in the field, while retaining favorable physicochemical properties.
Cyberknife radiosurgery for breast cancer spine metastases
Authors: Gagnon Gregory J. , Henderson Fraser C. , Gehan Edmund A. , Sanford Donna , Collins Brian T. , Moulds Jefferson C. , Dritschilo Anatoly 
Published: September 2007

AbstractBACKGROUND.There are few options for breast cancer patients with spinal metastases recurrent within a previous radiation treatment field. CyberKnife radiosurgery has been used in our institution to treat such patients. To evaluate their outcomes, as there are no comparable radiation treatment options, the outcomes were compared between 18 patients with spinal metastases from breast cancer treated with CyberKnife stereotactic radiosurgery, 17 of which had prior radiotherapy to the involved spinal region and were progressing, and 18 matched patients who received conventional external beam radiotherapy (CRT) up‐front for spinal metastases.METHODS.Radiosurgery was delivered in 3 to 5 fractions to doses ranging from 2100 to 2800 cGy. Women were matched to patients in a CRT group with respect to time from original diagnosis to diagnosis of metastases, estrogen receptor / progesterone receptor (ER/PR) status, presence or absence of visceral metastases, prior radiotherapy, and prior chemotherapy. Survival and complications were compared between treatment groups. Surviving patients were followed out to 24 months.RESULTS.The CyberKnife and CRT groups were comparable along all matching dimensions and in performance status before treatment. Outcomes of treatment were similar for patients in both groups; ambulation, performance status, and pain worsened similarly across groups posttreatment. Survival and the number of complications appeared to favor the CyberKnife group, but the differences did not reach statistical significance.CONCLUSIONS.The statistical comparability of the CyberKnife and CRT groups reflects the small sample size and stringent requirements for significance of the matched‐pair analysis. Nevertheless, comparability in these difficult cases shows that salvage CyberKnife treatment is as efficacious as initial CRT without added toxicity. Cancer 2007. © 2007 American Cancer Society.
An approach to coupled thermal hydraulics and structural mechanics problems for the MEGAPIE spallation source target
Authors: Smith Brian L. , Ni Liping , Zucchini Alberto 
Published: August 2007

AbstractThis paper describes some novel heat transfer and stress analysis problems that arose in the context of demonstrating the cooling principle of a liquid–metal neutron spallation source target. The design studies using computational fluid dynamics (CFD) resulted in an optimum flow configuration being defined for the coolant circulation. Simultaneously, stresses in the structural components were examined using finite element method (FEM) techniques. Central to the coupled CFD/FEM analysis strategy was the construction of an interface program, which enabled different specialist groups to carry out the thermal hydraulics and structural mechanics analyses using different commercial or in‐house software packages within a common project, and with fully consistent model data. For the studies reported here, the commercial CFD code CFX‐4 and the commercial structural analysis codes ABAQUS and ANSYS have been employed. Results for steady‐state operation of the target show that the critical lower target components are adequately cooled, and that stresses and displacements are well within tolerances. Transient analysis of a beamtrip and power‐up event is also described, showing that no stress crisis occurs. Copyright © 2007 John Wiley & Sons, Ltd.
Strontium deficient feldspar – structure and X – ray powder diffraction line broadening analysis
Authors: Nedić B. , Kremenović A. , Dondur V. , Dimitrijević R. 
Published: August 2007

AbstractVacant Sr‐feldspar was synthesized by thermal transformation of FAU zeolite and the structure was refined (space group I2/c). Two refinement procedures were performed: with and without micro strain modelling. Reliable structure model was achieved only with including micro strain modelling. Vacancies in the Sr2+ positions produce micro strain. The concentration of vacancies was the highest along [011] direction. (© 2007 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bauinvestitionen im Zeichen des demografischen Wandels – Rahmenbedingungen für die Wohnungswirtschaft
Authors: Rychter Alexander 
Published: September 2007

AbstractIn Deutschland wird in den kommenden Jahrzehnten die Zahl älterer Menschen infolge des demografischen Wandels deutlich zunehmen. Die entscheidenden Zahlen sind hinreichend bekannt: Schon im Jahr 2020 ist jeder vierte Deutsche älter als 65 Jahre, wobei sich diese Entwicklung in den kommenden Jahren weiter dynamisieren wird. Die Wohnungs‐ und Immobilienwirtschaft muss sich daher auf diese gravierenden Veränderungen einstellen. Tatsache ist: Die Zielgruppen an den Immobilienmärkten kehren sich schlichtweg um. Haben sich viele Bauträger noch in den vergangenen Jahrzehnten vornehmlich auf die Kundengruppe der jungen Familie im Einfamilienhaussektor konzentrieren können, steht heute immer mehr der ältere Mieter oder Käufer mit seinen besonderen Ansprüchen an eine Immobilie im Mittelpunkt des Interesses.
Schadensvermeidung bei Kelleraußenwänden aus Mauerwerk
Authors: Burkert Rainer 
Published: September 2007

AbstractMauerwerk ist für die Ausführung von Kellerwänden eine traditionelle, bewährte und auch gute Bauweise. In Anbetracht der heute üblichen kleineren Grundstücke und den sich daraus ergebenden Gebäudemaßen sowie aus wirtschaftlichen Gesichtspunkten sind Keller von der Mehrzahl der Bauherren nach wie vor auch gewünscht. Allerdings haben sich in den letzten 20 Jahren sowohl die Anforderungen an die Konstruktion, die verwendeten Materialien sowie die Rahmenbedingungen bei der Erstellung und Nutzung nachhaltig geändert.In diesem Zusammenhang treten bei der Erstellung von Kellermauerwerk Schäden auf, die der Autor für unnötig und leicht vermeidbar hält. Schadensursache ist meist nicht das verwendete Steinmaterial, sondern dessen unsachgemäße Verwendung durch fehlende oder falsche Planung.Die Reaktion “wir haben das schon immer so gemacht” ist sicher falsch und nicht vertretbar. Als Ingenieure stellen wir uns damit ein schlechtes Zeugnis aus.
Flexible und barrierearme Bauten mit Mauerwerk
Authors: Seim Werner 
Published: September 2007

AbstractFlexible Nutzungsmöglichkeiten und möglichst wenig Barrieren – dies sind zwei grundsätzliche Anforderungen, die bei allen Planungsentscheidungen im Hochbau bereits heute und in Zukunft noch verstärkt zu berücksichtigen sind. Einige statistische Daten, die in diesem Zusammenhang von Bedeutung sind, werden zitiert, und es wird erörtert, wie im Bestand die Nutzungsqualität mit angemessenem Aufwand erhöht werden kann. Für den Mauerwerksbau wird dargelegt, welche Konsequenzen sich aus der Forderung nach flexibleren Grundrissen ergeben. Dabei wird Bezug auf ein aktuelles Forschungsvorhaben genommen, das sich mit der örtlichen Verstärkung von Mauerwerkskonstruktionen mit aufgeklebten Faserverbundwerkstoffen befasst.
Leitbild Bauwirtschaft – Sinn, Nutzen und Entwicklung
Authors: Halstenberg Michael 
Published: September 2007

AbstractDie Bundesregierung hat einen Leitbildprozess der Branche angestoßen, sie moderiert und fördert ihn. Man kann provokant fragen: Ist das die Aufgabe einer Regierung? Wird ein solcher Prozess überhaupt benötigt und warum? Fragen, die durch eine Analyse der Entwicklung und der aktuellen Situation der Bauwirtschaft beantwortet werden sollen.
Synthesis, Structure and Magnetic Behaviour of Manganese(II) Selenolate Complexes ∞1[Mn(SePh)2], [Mn(SePh)2(bipy)2] and [Mn(SePh)2(phen)2] (bipy = bipyridyl, phen = phenanthroline)
Authors: Eichhöfer Andreas , Wood Paul T. , Viswanath Raghavan , Mole Richard A. 
Published: September 2007

AbstractThe manganese selenolate complex ∞1[Mn(SePh)2] has been prepared by reaction of Mn(OOCCH3)2 with 2 equiv.PhSeSiMe3 in thf. In the crystal structure, the compound forms one‐dimensional chains, and the bridging selenolate ligands result in relatively short metal–metal contacts of about 3 Å. Reaction with two equivalents of the Lewis bases 2,2′‐bipyridine and 1,10‐phenanthroline yielded the monomeric octahedral complexes [Mn(SePh)2(2,2′‐bipy)2] and [Mn(SePh)2(1,10‐phen)2], respectively. The magnetic and optical properties of these complexes have been investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Fine‐Tuning Ligands for Catalysis Using Supramolecular Strategies
Authors: Slagt Vincent F. , Kaiser Patrick , Berkessel Albrecht , Kuil Mark , Kluwer Alexander M. , van Leeuwen Piet W. N. M. , Reek Joost N. H. 
Published: September 2007

AbstractCoordinative bonds have been used to prepare supramolecular ligands leading to well‐defined catalysts formed by assembly. The construction of these ligands is based on selective metal–ligand interactions between nitrogen donor atoms of phosphorus‐nitrogen building blocks and various zinc(II) porphyrins. The major advantage of this supramolecular approach of catalyst preparation is the simplification of ligand variation enabling straightforward modification of steric, electronic and chiral properties of the supramolecular ligand. A large number of new ligands becomes accessible by this modular variation of the building blocks. The ligand assembly based on pyridyl phosphites and zinc(II) porphyrin with electron‐withdrawing substituents led to a twelve‐fold increase in activity and an increase in enantioselectivity from 17 to 50 % in the rhodium‐catalyzed hydrogenation of dimethyl itaconate. The first examples of assemblies based on non‐chiral ligands and chiral zinc(II) porphyrin template molecules show, as proof of principle, an enantiomeric excess up to 18 % in the asymmetric palladium‐catalyzed allylic alkylation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Solid‐State Anion–Guest Encapsulation by Metallosupramolecular Capsules Made from Two Tetranuclear Copper(II) Complexes
Authors: Pardo Emilio , Bernot Kevin , Lloret Francesc , Julve Miguel , Ruiz‐García Rafael , Pasán Jorge , Ruiz‐Pérez Catalina , Cangussu Danielle , Costa Valeria , Lescouëzec Rodrigue , Journaux Yves 
Published: September 2007

AbstractA new cationic tetranuclear copper(II) complex self‐assembles from one 1,3‐phenylenebis(oxamato) (mpba) bridging ligand and four CuII ions partially blocked with N,N,N′,N′‐tetramethylethylenediamine (tmen) terminal ligands. In the solid state, two of these tetracopper(II) oxamato complexes of bowl‐like shape and helical conformation then serve as a building block for the generation of either hetero‐ (MP) or homochiral (MM/PP) dimeric capsules depending on the nature of the encapsulated anion guest, perchlorate or hexafluorophosphate. The overall magnetic behaviour of these metallosupramolecular capsules does not depend on the nature of the encapsulated anion guest, but it is consistent with the dimer‐of‐dimer structure of the tetracopper(II) cation host, where the interdimer magnetic coupling through the meta‐phenylenediamidate bridge is negligibly smallrelative to the reasonably strong intradimer one across the oxamato bridge.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cationic P(OPh)3‐ or PPh3‐Rhodium(I) Complex‐Catalyzed Isomerizations of 5‐Alkynals to δ‐Alkynyl Ketones, Cyclopent‐1‐enyl Ketones, and Cyclohexenones
Authors: Tanaka Ken , Sasaki Kaori , Takeishi Kenzo , Hirano Masao 
Published: August 2007

AbstractWe have developed catalytic isomerizations of 5‐alkynals to γ‐alkynyl ketones and cyclopent‐1‐enyl ketones using [Rh{P(OPh)3}2]BF4 as a catalyst. Cu(OTf)2 and AgBF4 are also effective catalysts for the formation of γ‐alkynyl ketones. The substituents at the 4‐positions in 5‐alkynals play important roles in the selection of two different isomerization pathways. The first catalytic endo/trans hydroacylation of acyclic 5‐alkynals leading to cyclohexenones was also developed with [Rh(PPh3)2]BF4 as a catalyst. Crossover deuterium‐labeling studies indicated that these isomerization reactions proceed intramolecularly.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Fast DKR of Amines Using Isopropyl 2‐Methoxyacetate as Acyl Donor
Authors: Veld Martijn A. J. , Hult Karl , Palmans Anja R. A. , Meijer E. W. 
Published: September 2007

AbstractThe dynamic kinetic resolution (DKR) of various primary amine substrates was performed using a modified version of the Bäckvall system. A single equivalent of isopropyl 2‐methoxyacetate was used as acyl donor in combination with p‐MeO Shvo complex as the racemization catalyst and Novozym 435 as the acylation catalyst. A reaction temperature of 100 °C was employed to ensure a high racemization rate. Adding 2,4‐dimethyl‐3‐pentanol (DMP) as hydrogen donor at a concentration of 0.5 M successfully suppressed side product formation. Under these modified DKR conditions, complete conversion was observed for most substrates within 26 h showing both high ee values and good chemoselectivity, whereas the original system required a reaction time of 72 h.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Contactless conductivity detection of sodium monofluoroacetate in fruit juices on a CE microchip
Authors: Lu Qin , Wu Peter , Collins Greg E. 
Published: September 2007

AbstractRapid and quantitative determination of sodium monofluoroacetate in diluted fruit juices (dilution 1:9 v/v in deionized water) and tap water was performed by microchip CE, using contactless conductivity detection. A separation buffer consisting of 20 mM citric acid and histidine at pH 3.5 enabled the detection of the monofluoroacetate (MFA) anion in diluted apple juice, cranberry juice, and orange juice without lengthy sample pretreatments. The analyte was very well separated from interfering anionic species present in juices and tap water. LODs in diluted juices and tap water were determined to be 125, 167, 138, and 173 μg/L for tap water, apple juice, cranberry juice, and orange juice, respectively, based upon an S/N of 3:1. Taking into account the dilution factor, the LODs for juice samples range from 1 to 2 mg/L, which is adequate for monitoring the toxicity of MFA in these juice beverages and tap water. The calibration curves for MFA in diluted fruit juices were linear over the range of 500 μg/L to 80 mg/L. The total analysis time for detecting the MFA anion in fruit juices was less than 5 min, which represents a considerable reduction in analysis time compared to other analytical methods currently used in food analysis.
CE of phytosiderophores and related metal species in plants
Authors: Xuan Yue , Scheuermann Enrico B. , Meda Anderson R. , Jacob Peter , von Wirén Nicolaus , Weber Günther 
Published: September 2007

AbstractPhytosiderophores (PS) and the closely related substance nicotianamine (NA) are key substances in metal uptake into graminaceous plants. Here, the CE separation of these substances and related metal species is demonstrated. In particular, the three PS 2′‐deoxymugineic acid (DMA), mugineic acid (MA), and 3‐epi‐hydroxymugineic acid (epi‐HMA), and NA, are separated using MES/Tris buffer at pH 7.3. Moreover, three Fe(III) species of the different PS are separated without any stability problems, which are often present in chromatographic analyses. Also divalent metal species of Cu, Ni, and Zn with the ligands DMA and NA are separated with the same method. By using a special, zwitterionic CE capillary, even the separation of two isomeric Fe(III) chelates with the ligand ethylenediamine‐N,N′‐bis(o‐hydroxyphenyl)acetic acid (EDDHA) is possible (i.e., meso‐Fe(III)‐EDDHA and rac‐Fe(III)‐EDDHA), and for fast separations of NA and respective divalent and trivalent metal species, a polymer CE microchip with suppressed EOF is described. The proposed CE method is applicable to real plant samples, and enables to detect changes of metal species (Cu‐DMA, Ni‐NA), which are directly correlated to biological processes.
Utility of toluidine blue in oral premalignant lesions and squamous cell carcinoma: Continuing research and implications for clinical practice
Authors: Epstein Joel B. , Sciubba James , Silverman Sol , Sroussi Herve Y. 
Published: August 2007

AbstractToluidine blue (TB) has been shown to aid in the detection and diagnosis of oropharyngeal squamous cell carcinoma (OSCC) and oral premalignant lesions (OPLs). TB has been shown to enhance visualization of oral lesions and assist in identifying sites of increased risk of dysplastic/malignant change and promote biopsy. TB has been shown to identify lesions with molecular changes associated with risk of progression of OPLs to OSCC. A recent prospective longitudinal study showed TB retention in histologic benign lesions and lesions with mild dysplasia that are at increased risk of progression to cancer. Clinical trials show that TB is useful in identifying asymptomatic OSCC and premalignant lesions at risk of progressing to SCC, which might otherwise be undetected until lesions become more advanced. The data supports TB use in oral examination of patients at risk of OSCC. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Development of prototype for navigated real‐time sonography for the head and neck region
Authors: Helbig Matthias , Krysztoforski Krzysztof , Krowicki Pawel , Helbig Silke , Gstoettner Wolfgang , Kozak Josef 
Published: August 2007

AbstractBackground.To date, few imaging methods have been established for the head and neck region, in particular for soft tissues, that allow adequate visualization and simultaneously adequate real‐time orientation.Methods.We report a new method using a navigated ultrasound device and a navigated surgical instrument that allows—even in the absence of bony landmarks—appropriate visualization and reliable orientation in real time.Results.The practical applicability of the system was tested. Good handling and acceptance of the system could be shown. The “3‐dimensional error” derived from the deviations in all 3 dimensions lies at 0.64 mm.Conclusions.With this ultrasound‐guided navigated procedure, an accurate approach of soft tissue structures with a surgical instrument is possible. Changes of the situs are represented in real time. © 2007 Wiley Periodicals, Inc. Head Neck, 2008
A nonlinear data‐driven model for synthetic generation of annual streamflows
Authors: Sudheer K. P. , Srinivasan K. , Neelakantan T. R. , Srinivas V. V. 
Published: September 2007

AbstractA hybrid model that blends two non‐linear data‐driven models, i.e. an artificial neural network (ANN) and a moving block bootstrap (MBB), is proposed for modelling annual streamflows of rivers that exhibit complex dependence. In the proposed model, the annual streamflows are modelled initially using a radial basis function ANN model. The residuals extracted from the neural network model are resampled using the non‐parametric resampling technique MBB to obtain innovations, which are then added back to the ANN‐modelled flows to generate synthetic replicates. The model has been applied to three annual streamflow records with variable record length, selected from different geographic regions, namely Africa, USA and former USSR. The performance of the proposed ANN‐based non‐linear hybrid model has been compared with that of the linear parametric hybrid model. The results from the case studies indicate that the proposed ANN‐based hybrid model (ANNHM) is able to reproduce the skewness present in the streamflows better compared to the linear parametric‐based hybrid model (LPHM), owing to the effective capturing of the non‐linearities. Moreover, the ANNHM, being a completely data‐driven model, reproduces the features of the marginal distribution more closely than the LPHM, but offers less smoothing and no extrapolation value. It is observed that even though the preservation of the linear dependence structure by the ANNHM is inferior to the LPHM, the effective blending of the two non‐linear models helps the ANNHM to predict the drought and the storage characteristics efficiently. Copyright © 2007 John Wiley & Sons, Ltd.