bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterometallic Transition‐Metal Complexes Based on 1‐Carboxy‐1′‐(diphenylphosphanyl)ferrocene, (tmeda/pmdta)Zinc(II), and Gold(I) Units
Authors: Kühnert Janett , Ecorchard Petra , Lang Heinrich 
Published: September 2008

AbstractThe synthesis of the ZnII and TiIV carboxylates [LnM(O2CfcPPh2)2] {LnM = (tmeda)Zn (3); LnM = (pmdta)Zn (8); LnM = [Ti] (12); fc = (η5‐C5H4)2Fe; tmeda = N,N,N′,N′‐tetramethylethylenediamine; pmdta = 1,1,4,7,7‐pentamethyldiethylentriamine; [Ti] = (η5‐C5H5)2Ti} and [LnM(X)(O2CfcPPh2)] {LnM = (pmdta)Zn, X = Cl (7); LnM = [Ti], X = Me (10)} is reported. The reaction of Hdpf (1) {Hdpf = (η5‐C5H4CO2H)(η5‐C5H4PPh2)Fe} with [(tht)AuCl] (13) (tht = tetrahydrothiophene) gave [(Hdpf)AuCl] (14). Treatment of 3, 7, and 10 with 13 produced trimetallic [LnM(X){(O2CfcPPh2)AuCl}] {LnM = [Ti], X = Me (15); LnM = (pmdta)Zn, X = Cl (16)} or [(tmeda)Zn{(O2CfcPPh2)AuCl}2] (17). Heptametallic complexes were accessible by the reaction of 14 with HC≡CR {R = Fc, Rc; Fc = (η5‐C5H4)(η5‐C5H5)Fe; Rc = (η5‐C5H4)(η5‐C5H5)Ru}, whereby [(H2NEt2){(O2CfcPPh2)AuCl}] (18) and [(H2NEt2){(O2CfcPPh2)AuC≡CR}] {R = Fc (20a), Rc (20b)} were formed. Further reaction of 20a and 20b with [(tmeda)ZnCl2] (2) gave [(tmeda)Zn{(O2CfcPPh2)AuC≡CR}2] {R = Fc (21a), Rc (21b)}. The solid‐state structures of 3, 7, 12, and 18 were determined by single‐crystal X‐ray diffraction. The Zn atom in 3 is in a distorted tetrahedral environment, while in 7 it is part of a distorted bipyramidal arrangement. In 18, a stairlike 1D chain is built from three independent molecules of 18 by N–H···O hydrogen bonds and π–π interactions between phenyl or cyclopentadienyl rings of adjacent molecules. The cyclovoltammetric properties of 3, 7, 14, 16, 17, 18, 21a, and 21b are reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Structure of Zirconium and Hafnium Polymerisation Catalysts Stabilised by Very Bulky Aminopyridinato Ligands
Authors: Noor Awal , Kretschmer Winfried P. , Glatz Germund , Meetsma Auke , Kempe Rhett 
Published: September 2008

AbstractMono(aminopyridinato) complexes of the type [ApM(CH2C6H5)3] [M = Zr, Hf and Ap = aminopyridinate] were prepared by treating the three different sterically demanding aminopyridines with one equiv. of tetrabenzylzirconium or ‐hafnium. One of the three benzyl groups is η2‐coordinated in the solid state. However all of the three benzyl substituents are equivalent in solution as evidenced by the 1H NMR spectrum. Treatment of these neutral complexes with B(C6F5)3 afforded the corresponding zwitterionic dibenzyl complexes. The η6‐coordination of the phenyl ring of the B‐bound benzyl group to the metal centre was supported by 1H NMR spectroscopy and confirmed by single‐crystal X‐ray diffraction analysis. These zwitterionic complexes show very low activity for ethylene polymerisation at low temperature since the coordination site is blocked by the η6‐coordinated phenyl ring. At elevated temperature, moderate activity with the formation of high molecular weight polyethylene (PE) was observed. An attempted abstraction of the second benzyl group failed when the zwitterionic complexes were treated with an additional equivalent of B(C6F5)3. Using one equiv. of [R2(Me)NH][B(C6F5)4] (R = C16H33–C18H37) instead of B(C6F5)3, moderate activities of ethylene polymerisation were observed. Treatment of the aminopyridinato metal tribenzyls with [R2(Me)NH][B(C6F5)4] (R = C16H33–C18H37) gave active ethylene polymerisation catalysts which produced low molecular weight PE in the case of the zirconium analogues and higher molecular weight PE in the case of the hafnium example. Propylene homopolymerisation under the same conditions failed. Ethylene–propylene copolymers with separated propene units and alternating sequences were observed in the presence of both monomers.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Denial of Tris(C,N‐cyclometalated) Ruthenacycle: Nine‐Membered η6‐N,N‐trans or η2‐N,N‐cis RuII Chelates of 2,2′‐Bis(2‐pyridinyl)‐1,1′‐biphenyl
Authors: Saavedra‐Díaz Omar , Cerón‐Camacho Ricardo , Hernández Simon , Ryabov Alexander D. , Le Lagadec Ronan 
Published: September 2008

AbstractIn the attempt to prepare the tris(cyclometalated) ruthenium derivative of 2‐phenylpyridine, [Ru(η6‐C6H6)(phpy)Cl] was treated with Hg(phpy)2. The anticipated [Ru(phpy)3]n+ species was not formed. Instead, the product of oxidative coupling of two 2‐(2‐pyridinyl)phenyl ligands to form octahedral [RuII(phpy)(pbp)]PF6 with pbp = 2,2′‐bis(2‐pyridinyl)‐1,1′‐biphenyl was isolated; pbp forms a nine‐membered chelate with two N and two η2‐C=C donor centers. The binding of η2‐C=C donor units is weak as they are readily replaced by CO. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stable Trichlorosilane–Pyridine Adducts
Authors: Fester Gerrit W. , Wagler Jörg , Brendler Erica , Kroke Edwin 
Published: September 2008

AbstractThe prepapration, and first comprehensive spectroscopic and structural characterization of octahedral trichlorosilane adducts HSiCl3(Rpy)2 with R = H, 4‐CH3, 4‐C6H5, 3‐Br, 4‐CHCH2, 4‐C2H5, 4‐C(CH3)3 and 4‐N(CH3)2 is reported. The products are surprisingly stable in the solid state and easily obtained in high yield. Single‐crystal X‐ray diffraction analysis of HSiCl3(3‐Brpy)2 revealed relatively short Si–Cl bonds (218–223 pm) while the Si–N bonds (ca. 198 pm) are only slightly longer than in the corresponding H2SiCl2(Rpy)2adducts. Dismutation reactions were observed only in polar solvents at elevated temperatures.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Oxime‐Based Synthesis of New Chromogenic and Fluorogenic Oligosaccharides
Authors: Renaudet Olivier , Dumy Pascal 
Published: September 2008

AbstractA new simple approach for the synthesis of labelled oligosaccharides is described. Free synthetic carbohydrate recognition building blocks were conjugated with fluorogenic and chromogenic dyes under mild experimental conditions by using oxime ligation. The resulting oligosaccharide probes presenting well‐defined anomer configuration might find broad interests for recognition studies with a large panel of carbohydrate‐binding proteins. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Evaluation of Meldola Blue‐Carbon Nanotube‐Sol‐Gel Composite for Electrochemical NADH Sensors and Their Application for Lactate Dehydrogenase‐Based Biosensors
Authors: Arvinte Adina , Sesay Adama M. , Virtanen Vesa , Bala Camelia 
Published: September 2008

AbstractA novel MB‐SWNT‐sol‐gel nanocomposite material was prepared by the sol‐gel process incorporating a redox mediator and carbon nanotubes. The electrocatalytic properties of the nanomaterial based sensor toward NADH oxidation were studied by electrochemical measurements. Significant enhancement of oxidation current is obtained at electrodes modified by MB‐SWNT‐sol‐gel in comparison with the analogous carbon black and/or graphite composite modified electrode. The usefulness of the nanocomposite material as a matrix for immobilizing enzymes is also demonstrated. Analytical parameters of D‐lactate biosensors with and without SWNT in the hybrid film were compared demonstrating that performance of the biosensor was significantly improved when introducing SWNT.
Contribution of roots and hyphae to phosphorus uptake of mycorrhizal onion (Allium cepa L.)—A mechanistic modeling approach
Authors: Gashaw Deressa Tesfaye , Schenk Manfred K. 
Published: September 2008

AbstractPhosphorus uptake by plant roots and arbuscular mycorrhizae (AM) hyphae can be described based on morphological and physiological uptake characteristics and parameters affecting P transport in the soil to the uptake surface. The current study aimed to quantify the relative contribution of hyphae and roots to P uptake of onion and to investigate the associated mechanisms using a mechanistic simulation model. Onion was grown in a growth chamber under controlled conditions at five levels of P supply with (M) or without (NM) AM. Uptake by onion roots and AM hyphae was simulated separately using a nutrient‐uptake model, which was developed for roots. Model parameters describing P transport in the soil, as well as morphological and physiological uptake characteristics of roots and hyphae were derived from soil and nutrient‐solution experiments. The model fairly described P uptake of M and NM plants at the highest level of P supply (28 µM P in soil solution) where roots and hyphae contributed nearly equally to P uptake of M plants. However, at lower P levels (≤0.41 µM P), hyphae accounted for nearly the whole P uptake whereas roots hardly explained any uptake. The effectiveness of AM hyphae at low P supply was well explained by their favorable morphological and physiological uptake properties. Hyphae were characterized by a diameter of 3 × 10–4 cm, a Km of 0.25 µM, and a Cmin of 0.04 µM, values that are about 200, 40, and 10 times lower, respectively, compared to those of roots. Not more than 60% of the uptake at lower levels of P supply could be explained by the sum of predicted uptake of roots and hyphae suggesting that hyphae and roots may have used mechanisms additional to those described by the model to mobilize P. This work demonstrated that mechanistic models can be useful tools to study the role of AM in P uptake of plants, although reliable estimation of model parameters, especially physiological uptake properties of AM, is still limiting this approach.
Impact of the heatwave in 2003 on the summer CH4 budget of a spruce forest with large variation in soil drainage: A four‐year comparison (2001–2004)
Authors: Fiedler Sabine , Lamers Marc , Ingwersen Joachim , Streck Thilo , Stahr Karl , Jungkunst Hermann F. 
Published: September 2008

AbstractWell‐aerated soils are sinks for atmospheric methane (CH4) whereas hydromorphic soils act as sources. Both CH4 oxidation and production are highly sensitive to variation in soil moisture. Significant changes of net CH4 fluxes from soils can therefore be expected to accompany redistribution of precipitation in the course of climate change where more extreme events are predicted for the future. The extreme summer drought in 2003 offered the opportunity to study the impact of such events on methane fluxes under field conditions. The objective was to evaluate the impact of the summer drought in 2003 on net methane budget of a spruce‐forest ecosystem. We studied net CH4 flux (bi‐)weekly during the summers of 2000–2004 using a closed‐chamber technique on six different soil types ranging from well‐aerated Cambisols, to poorly drained Gleysols and a wet Histosol in a cool‐humid spruce forest.
Unprecedented Route to Ordered Polyaniline: Direct Synthesis of Highly Crystalline Fibrillar Films with Strong π‐π Stacking Alignment
Authors: Gospodinova Natalia , Ivanov Dimitri A. , Anokhin Denis V. , Mihai Iulia , Vidal Loïc , Brun Sulyvan , Romanova Julia , Tadjer Alia 
Published: September 2008

AbstractFilms of polyaniline (PANI) featuring about 80% crystallinity and characterised with strong π‐π stacking alignment parallel to the film surface have been obtained directly after the original synthesis upon simple drying of the aqueous PANI suspension. A strong anisotropy in the growth of the nano‐sized crystals produced during the synthesis results in the formation of micrometer‐length fibrils perpendicular to the film surface in the course of water evaporation. The regular intercalation of water molecules between the PANI chains seems to be crucial for their ordering throughout the synthesis and film formation.magnified image
DFT–GIAO–NBO and 13C NMR study of the δ‐syn‐axial effect in 2,4‐disubstituted adamantanes
Authors: Mikhova B. , Stamboliyska B. , Koch A. , Duddeck H. , Kleinpeter E. 
Published: September 2008

AbstractSix groups of diastereomeric 2,4‐disubstituted adamantanes were studied with DFT–GIAO–NBO (natural orbital analysis) methods. The calculated 13C chemical shifts reproduce well the experimental data. It was found that among all diastereomers, those bearing substituents in δ‐syn‐axial positions showed the largest overall deshielding, i.e. the sum of all 13C chemical shifts [Σδ(13C)] was the greatest and also had the highest delocalization contribution to the molecular energy evaluated with NBO. The higher delocalization energy is proposed to be the origin of the deshielding δ‐syn‐axial effect. Copyright © 2008 John Wiley & Sons, Ltd.
Complete assignments of 1H and 13C NMR spectral data for three sesquiterpenoids from Inula helenium
Authors: Huo Yan , Shi Haiming , Wang Mengyue , Li Xiaobo 
Published: September 2008

AbstractThe complete assignments of all the 1H and 13C NMR signals of three sesquiterpene lactones, 4‐oxo‐5(6),11‐eudesmadiene‐8,12‐olide (1), 4‐oxo‐11‐eudesmaene‐8,12‐olide (2) and (1(10)E)‐5β‐Hydroxygermacra‐1(10),4(15),11‐trien‐8, 12‐olide (3), were carried out by various 2D NMR experiments. Compounds 1–3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor‐sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The 13C‐NMR data of compound 3 was also reported for the first time. Copyright © 2008 John Wiley & Sons, Ltd.
Hospitalist educators: future of inpatient internal medicine training
Authors: Goldenberg Jill , Glasheen Jeffrey J. 
Published: September 2008

AbstractAcademic hospitalists have grown in number and influence over the past decade. This has fueled concerns about the effect of hospitalists on resident and student education. While the bulk of the literature favors the hospitalist teaching model to a more traditional model concerns remain that hospitalists may negatively imipact housestaff autonomy and reduce exposure to subspeciality physicians. This paper will review the literature exploring the effect of the hospitalist teaching model on resident and student education. Mt Sinai J Med 75: 430–435, 2008. © 2008 Mount Sinai School of Medicine
Achieving hospital medicine's promise through internal medicine residency redesign
Authors: Glasheen Jeffrey J. , Goldenberg Jill , Nelson John R. 
Published: September 2008

AbstractThe promise of the hospital medicine movement is that the hospitalist model of care will provide better outcomes than the system it replaced. This means improving the quality and processes of care, reducing inefficiencies and lowering costs. Despite some documented improvements in these areas hospitalists have yet to achieve their pinnacle. These shortfalls likely result from training providers in residencies that have yet to evolve to address the specific needs of hospitalists. While most internal medicine residency training programs stress inpatient care they underemphasize key components of a successful hospitalist career. This paper overviews the state of the hospitalist movement, the current educational training deficiencies and the methods to deliver hospitalist‐focused training. Mt Sinai J Med 75: 436–441, 2008. © 2008 Mount Sinai School of Medicine
Preparation and mechanical properties of well‐aligned and well‐oriented poly(vinyl alcohol) nanoribbon
Authors: Iwashita Mai , Kotera Masaru , Nishino Takashi 
Published: September 2008

AbstractWe report a novel, economical method of preparing well‐aligned and well‐oriented nanoribbons made of poly(vinyl alcohol) (PVA). The method requires no special equipment and easily produces nanoribbon. The structure of uniaxially drawn nanoribbon was investigated by polarized microscopy, polarized FT‐IR, and X‐ray diffraction, which showed high molecular and crystallite orientations. The well‐aligned PVA nanoribbon, measuring several tens of micrometer width and around 400 nm thickness, had a Young's modulus of 9 GPa and a tensile strength of 350 MPa. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characteristic of polybenzoxazine with phenylnitrile functional group
Authors: Qi Huimin , Ren Hao , Pan Guangyan , Zhuang Yuanqi , Huang Farong , Du Lei 
Published: September 2008

AbstractThe phenylnitrile functional benzoxazine monomers, 3‐phenyl‐3,4‐dihydro‐ 6‐nitril‐2H‐1,3‐benzoxazine (NBen‐a) and 4,4′‐bis(3,4‐dihydro‐6‐nitril‐2H‐1,3‐benzoxazine‐3‐yl)phenylether (NBen‐De), were synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H‐NMR). The curing behaviors of NBen‐a and NBen‐De were characterized by differential scanning calorimetry (DSC) and FTIR. Thermal stability and dynamic mechanical properties of the cured NBen‐a and NBen‐De were investigated using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The cured NBen‐a and NBen‐De showed glass transition temperature (Tg), the thermal stability improved as compared to the analogous polybenzoxazine without phenylnitrile group. Copyright © 2008 John Wiley & Sons, Ltd.
Active drug safety surveillance: a tool to improve public health
Authors: Platt Richard , Madre Leanne , Reynolds Robert , Tilson Hugh 
Published: September 2008

AbstractPurposeEnsuring that drugs have an acceptable safety profile and are used safely is a major public health priority. The Centers for Education and Research on Therapeutics (CERTs) convened experts from academia, government, and industry to assess strategies to increase the speed and predictive value of generating and evaluating safety signals, and to identify next steps to improve the US system for identifying and evaluating potential safety signals.MethodsThe CERTs convened a think tank comprising representatives of the groups noted above to address these goals.ResultsParticipants observed that, with the increasing availability of electronic health data, opportunities have emerged to more accurately characterize and confirm potential safety issues. The gain for public health from a highly coordinated network of population‐based databases for active surveillance is great and within reach, although operational questions remain. A collaborative network must create a working definition of a safety signal, screening algorithms, and criteria and strategies to confirm or refute a signal once identified through screening. Guidelines are needed for when and how to communicate a signal exists and is being evaluated, as well as the outcome of that evaluation.ConclusionA public–private partnership to create a network of government and private databases to routinely evaluate and prioritize safety questions is in the public interest. Better methods are needed, and a knowledgeable workforce is required to conduct the surveillance and understand how to interpret the results. The international community will benefit from the availability of better methods and more experts. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of the folding mechanism of highly homologous proteins in the lipid‐binding protein family
Authors: Ropson Ira J. , Boyer Joshua A. , Schaeffer Blake A. , Dalessio Paula M. 
Published: September 2008

AbstractThe folding mechanism of two closely related proteins in the intracellular lipid‐binding protein family, human bile acid‐binding protein (hBABP), and rat bile acid‐binding protein (rBABP) were examined. These proteins are 77% identical (93% similar) in sequence. Both of these single domain proteins fit well to a two‐state model for unfolding by fluorescence and circular dichroism at equilibrium. Three phases were observed during the unfolding of rBABP by fluorescence but only one phase was observed during the unfolding of hBABP, suggesting that at least two kinetic intermediates accumulate during the unfolding of rBABP that are not observed during the unfolding of hBABP. Fluorine NMR was used to examine the equilibrium unfolding behavior of the W49 side chain in 6‐fluorotryptophan‐labeled rBABP and hBABP. The structure of rBABP appears to be more dynamic than that of hBABP in the vicinity of W49 in the absence of denaturant, and urea has a greater effect on this dynamic behavior for rBABP than for hBABP. As such, the folding behavior of highly sequence related proteins in this family can be quite different. These differences imply that moderately sized proteins with high sequence and structural similarity can still populate quite different structures during folding. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Applying undertaker cost functions to model quality assessment
Authors: Archie John , Karplus Kevin 
Published: September 2008

AbstractUndertaker is a program designed to help predict protein structure using alignments to proteins of known structure and fragment assembly. The program generates conformations and uses cost functions to select the best structures from among the generated conformations. This paper describes the use of Undertaker's cost functions for model quality assessment. We achieve an accuracy that is similar to other methods, without using consensus‐based techniques. Adding consensus‐based features further improves our approach substantially. We report several correlation measures, including a new weighted version of Kendall's τ (τ3) and show model quality assessment results superior to previously published results on all correlation measures when using only models with no missing atoms. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Entangled‐photon generation from a quantum dot in cavity QED
Authors: Ajiki Hiroshi , Ishihara Hajime 
Published: September 2008

AbstractWe theoretically study polarization‐entangled photon generation from a single quantum dot in a microcavity. Entangled‐photon pairs with singlet or triplet Bell states are generated in the resonant‐hyperparametric scattering via dressed states in the cavity QED.Although co‐polarized non‐entangled photons are also generated, the generation is dramatically suppressed in the strong‐coupling limit owing to the photon blockade effect. Finite binding energy of biexciton is also important for the generation of photon pairs with high degree of entanglement. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid energy transfer and ist temperature dependence in π ‐conjugated dendrimers
Authors: Akai I. , Miyanari K. , Shimamoto T. , Fujii A. , Nakao H. , Okada A. , Kanemoto K. , Karasawa T. , Ishida A. , Yamada A. , Katayama I. , Takeda J. , Kimura M. 
Published: September 2008

AbstractWe investigate a rapid energy transfer (ET) process and its temperature dependence in a star‐shaped stilbenoid phthalocyanine (SSS1Pc) dendrimer having π ‐conjugated light‐harvesting (LH) antennas. In SSS1Pc, intense core‐photoluminescence is observed under selective excitation on the LH‐antenna as a result of the highly efficient ET from the LH‐antenna. Pump‐probe experiments show that ET occurs rapidly with a rising time constant (∼ 250 fs).To understand such rapid ET, we employ a simplified ET model through a π ‐conjugated network between the Lhantenna and the core that takes into account the steric hindrance between the LH‐antenna subunits. Our model reveals that the highly efficient ET at room temperature in SSS1Pc takes place through the π ‐conjugated network mediated by a thermally activated torsional vibration of the aromatic ring subgroup in the LH‐antenna. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Up to 30 times enhancement of deep UV emission at room temperature by prolonged excitation of localized exciton in NaCl:I crystal
Authors: Akimoto Ikuko , Shimozato Masahiro , Kan'no Ken‐ichi 
Published: September 2008

AbstractA material emitting DUV light at room temperature is promising for an application to a new laser action. We report the remarkable phenomena that deep ultra‐violet (DUV) emission at 220 nm, so‐called NE emission, in NaCl:I crystal is enhanced up to 30 times at room temperature by prolonged excitation of the localized exciton. Such an accumulated effect is kept even if the excitation is interuped for a few minutes but is completely reset by white light irradiation at room temperature. The phenomena are discussed considering thermal ionization of iodine anion by the VUV light excitation, trapping of dissociated electrons in hole centers and recombination of electrons and iodine hole centers. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)