bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effective temperature vs. line‐depth ratio for ELODIE spectra: Gravity and rotational velocity effects
Authors: Biazzo K. , Frasca A. , Catalano S. , Marilli E. 
Published: October 2007

AbstractThe dependence on the temperature of photospheric line‐depth ratios (LDRs) in the spectral range 6190–6280 Å is investigated by using a sample of 174 ELODIE Archive stellar spectra of luminosity class from V to III. The rotational broadening effect on LDRs is also studied. We provide useful calibrations of effective temperature versus LDRs for giant and main sequence stars with 3800 ≃ Teff ≃6000 K and v sin i in the range 0–30 km s–1. We found that, with the exception of very few line pairs, LDRs, measured at a spectral resolution as high as 42 000, depend on v sin i and that, by neglecting the rotational broadening effect, the Teff determination can be wrong by ∼100 K in the worst cases. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Porphyrin Substituents on Film Structure and Photoelectrochemical Properties of Porphyrin/Fullerene Composite Clusters Electrophoretically Deposited on Nanostructured SnO2 Electrodes
Authors: Imahori Hiroshi , Ueda Masahiro , Kang Soonchul , Hayashi Hironobu , Hayashi Shinya , Kaji Hironori , Seki Shu , Saeki Akinori , Tagawa Seiichi , Umeyama Tomokazu , Matano Yoshihiro , Yoshida Kaname , Isoda Seiji , Shiro Motoo , Tkachenko Nikolai V. , Lemmetyinen Helge 
Published: October 2007

AbstractWe have systematically examined the substituent effects of meso‐tetraphenylporphyrins on film structures and the photoelectrochemical properties of the composite clusters of free‐base porphyrin and C60 electrophoretically deposited on nanostructured SnO2 electrodes. The photocurrent generation efficiency was found to correlate with the complexation ability of the porphyrin for C60. Basically, the incident photon‐to‐current efficiency (IPCE) value was increased with increasing relative amounts of the porphyrin versus C60 in the films. The unique molecular arrangement of the porphyrin with the simple, specific substituents (i.e., methoxy groups at the meta‐positions of the meso‐phenyl rings of tetraphenylporphyrins (3,5‐OMeTPP; TPP=tetraphenylporphyrin)) and C60 on SnO2 electrodes resulted in the largest IPCE value (ca. 60 %) among this type of photoelectrochemical device. The rapid formation of the composite clusters and microcrystals from the combination of 3,5‐OMeTPP and C60 in a mixed solvent is unique as the association is accelerated by intermolecular interactions (i.e., hydrogen‐bonding and CH–π interactions) between the methoxy groups of the porphyrins and the porphyrin/C60, in addition to the π–π interactions between the porphyrins/C60 and C60 molecules. Both the films and single crystals composed of the porphyrin and C60 exhibited remarkably high electron mobility (7×10−2 and 0.4 cm2 V−1 s−1), which is comparable to the value for highly efficient bulk heterojunction solar cells. Our experimental results have successfully demonstrated the importance of nanostructured electron‐ and hole‐transporting pathways in bulk heterojunction solar cells. Such a finding will provide basic and valuable information on the design of molecular photovoltaics at the molecular level.
Stereochemical Consequences of Threefold Symmetry in Asymmetric Catalysis: Distorting C3 Chiral 1,1,1‐Tris(oxazolinyl)ethanes (“Trisox”) in CuII Lewis Acid Catalysts
Authors: Foltz Carole , Stecker Björn , Marconi Guido , Bellemin‐Laponnaz Stéphane , Wadepohl Hubert , Gade Lutz H. 
Published: October 2007

AbstractThe underlying conceptual differences in exploiting two‐ and threefold rotational symmetry in the design of chiral ligands for asymmetric catalysis have been addressed in a comparative study of the catalytic performance of bisoxazoline (BOX) and tris(oxazolinyl)ethanes (trisox) containing copper(II) Lewis acid catalysts. The differences become apparent in constructing new catalysts by systematically “deforming” the stereodirecting ligand by inverting chiral centres or replacing chiral by achiral oxazolines. The catalytic α‐amination of ethyl 2‐methylacetoacetate with dibenzyl azodicaboxylate, which occurs with high enantioselectivity for both Ph2‐BOX and Ph3‐trisox copper catalysts, has been employed as the test reaction. In the trisox–copper complex [CuII(iPr3‐trisox)(κ2‐O,O′‐MeCOCHCOOEt)]+[BF4]− (1), which was characterised by X‐ray diffraction, two of the oxazoline groups are coordinated to the central copper atom, whilst the third oxazoline unit is dangling with the N‐donor pointing away from the metal centre. A similar arrangement is found for the stereochemically “mixed” C1‐trisox complex [CuII{(Ph3‐trisox(R,S,S)}(κ2‐O,O′‐MeCOCHCOOEt)(H2O)]+[ClO4]− (2), in which the phenyl substituents adopt a first coordination sphere meso arrangement. The almost identical selectivity of the Ph3‐trisox(R,R,R)‐ and Ph2‐BOX(R,R)‐derived catalysts is as expected from the proposed model of the active catalyst based on a partially decoordinated podand. The behaviour of the “desymmetrised” trisox–Cu catalysts may be rationalised in terms of a general steady‐state kinetic model for the three possible active bisoxazoline–copper species, which are expected to be in rapid exchange with each other in solution. This applies to both the trisox derivatives with stereochemically inverted and achiral oxazoline rings. The study underscores previous observations of superior performance of the catalysts bearing C3‐chiral stereodirecting ligands as compared to systems of lower symmetry.
Convenient Syntheses and Transformations of 2‐C‐Malonyl Carbohydrates
Authors: Yin Jian , Sommermann Thomas , Linker Torsten 
Published: October 2007

Abstract2‐C‐malonyl carbohydrates were synthesized in only few steps and high yields by radical additions of malonates to glycals. For the first time, the undesired formation of nitrates was completely suppressed with anhydrous cerium ammonium nitrate (CAN) as oxidizing agent. A coherent explanation for the high stereoselectivities of the additions togluco‐configured glycals was provided by variation of the substituents in the 3‐position. We established steric effects for the face selectivity, and electronic effects strongly influence the reactivity of the double bonds. The scope and limitation of transition‐metal‐mediated radical reactions in the synthesis of 2‐C‐branched carbohydrates was thoroughly investigated. Thus, unsaturated disaccharides and benzyl‐protected glycals were used as substrates for the first time. Finally, the 2‐C‐malonyl carbohydrates were transformed into various products by decarboxylation, saponification and reduction, which afforded interesting precursors forC‐disaccharides. In this paper we describe the syntheses of more than 40 new 2‐C‐analogues of carbohydrates, which were isolated in high yields in analytically pure form. Therefore, the transition‐metal‐mediated radical addition of malonates to glycals offers a simple and convenient entry to such important carbohydrate derivatives.
On the Conjugation Length for Oligo(ethynylnaphthalene)‐Based Molecular Rods
Authors: Benniston Andrew C. , Harriman Anthony , Rewinska Dorota B. , Yang Songjie , Zhi Yong‐Gang 
Published: October 2007

AbstractThe synthesis is described for a small series of oligomers built from (2, 3, 4 or 6) ethynyl‐naphthalene repeat units and end‐capped with solubilising 1,2,3‐tris‐dodecyloxy‐benzene groups. These compounds absorb in the near‐UV region and exhibit strong fluorescence in both fluid solution and a glassy matrix at 77 K. The spectral profiles are fully consistent with a structurally heterogeneous ground state becoming more planar upon excitation and with the low‐temperature glass further stabilising the co‐planar orientation. The absorption and fluorescence maxima move towards lower energy with increasing number of repeat units and there is a corresponding increase in the Huang–Rhys factor for the radiative process. The non‐radiative rate constants also depend on molecular length and are well explained in terms of the energy‐gap law. In contrast, very weak phosphorescence is observed at 77 K for which the peak maximum and lifetime remain insensitive to the number of naphthalene units. The triplet lifetimes recorded at ambient temperature are also independent of the molecular length but the triplet–triplet absorption spectra change throughout the series. These results are discussed in terms of the degree of electronic coupling between adjacent repeat units for each of the relevant excited states. During these studies it was noted that the rate of intersystem crossing to the triplet manifold is but weakly affected by heavy‐atom perturbers. A non‐fluorescent complex is formed between iodoethane and the molecular rod but the corresponding bimolecular process occurs at well below the diffusion‐controlled limit. This behaviour is considered in terms of spin‐orbit coupling between the excited states and takes account of the differing conjugation lengths.
Functionalised Hybrid Materials of Conducting Polymers with Individual Fibres of Cellulose
Authors: Kelly Fern M. , Johnston James H. , Borrmann Thomas , Richardson Michael J. 
Published: October 2007

AbstractPolypyrrole and polyaniline conducting polymer composites with individual fibres of cellulose have been successfully prepared and characterised. For this, individual Kraft paper pulp fibres have been fully encapsulated with polypyrrole and polyaniline by direct polymerisation of the respective monomers using ferric chloride and ammonium persulfate as the oxidants. These novel conducting polymer/cellulose fibre composite materials exhibit the inherent properties of both components. They include the electrical and chemical properties of polypyrrole and polyaniline and the strength, flexibility and available surface areas of the cellulose fibre. This allows for interesting opportunities for the development of new added‐value products in the paper and packaging industries. Additionally, by utilising the redox active surface of the fibre's polymer coating, silver ions have been reduced to silver metal, thereby producing cellulose/conducting polymer/silver composites. Silver and its compounds have long been identified for their bactericidal effects and thus antimicrobial properties are imparted to the hybrid materials. This gives rise to applications requiring the inhibition of microbial growth. The chemical and physical characterisation of such products has been carried out using scanning electron microscopy (SEM), cyclic voltammetry, X‐ray photoelectron spectroscopy (XPS) energy dispersive spectroscopy (EDS) and electrical conductivity measurements, and additionally the testing of their antimicrobial activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Nucleosides with 5′‐Fixed Lipid Groups – Synthesis and Anchoring in Lipid Membranes
Authors: Brodersen Nicolai , Li Jun , Kaczmarek Oliver , Bunge Andreas , Löser Ludwig , Huster Daniel , Herrmann Andreas , Liebscher Jürgen 
Published: October 2007

AbstractNucleosides were synthesized bearing one or two lipophilic groups at the 5′‐position. The lipophilic substituents can be fixed at a 5′‐amino group or at the 5′‐phosphate moiety. Selected examples of these lipophilic nucleosides are shown by solid‐state NMR spectroscopy to anchor in lipid double layers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Novel 4‐Aminoquinolines through Microwave‐Assisted SNAr Reactions: a Practical Route to Antimalarial Agents
Authors: Melato Sergio , Coghi Paolo , Basilico Nicoletta , Prosperi Davide , Monti Diego 
Published: October 2007

Abstract4‐Aminoquinolines have recently been indicated to be an important class of chemotherapeutic agents for artemisinin‐based antimalarial combination therapy. A rapid, cheap, possibly clean and scalable route to 4‐aminoquinolines endowed with multiple diversity is therefore badly needed. Classically, they have been prepared by means of SNAr reactions, requiring hazardous or costly reagents and conditions and complex purification procedures. In this paper, microwave flash‐heating chemistry is shown to allow the efficient conversion of the available 4,7‐dichloroquinoline into a library of aminoquinolines in high yields and purities, with no need for further purification steps and requiring very short reaction times. Some of the compounds in this library were active against chloroquine‐sensitive and chloroquine‐resistant parasite strains.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Palladium‐Catalyzed Intramolecular C–O Bond Formation: An Approach to the Synthesis of Chiral Benzodioxocines
Authors: Neogi Arpita , Majhi Tirtha P. , Achari Basudeb , Chattopadhyay Partha 
Published: October 2007

AbstractPalladium‐catalyzed intramolecular aryl etherification using bulky binaphthylphosphane or bis(diphenylphosphanyl)ferrocene ligands is shown to be a convenient method for the synthesis of eight‐membered oxygen heterocycles. Application of this methodology to a sugar derivative led to the synthesis of chiral benzodioxocine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Effects of mimicking: acting prosocially by being emotionally moved
Authors: Stel Mariëlle , van Baaren Rick B. , Vonk Roos 
Published: October 2007

AbstractMimicry is functional for empathy and bonding purposes. Studies on the consequences of mimicry at a behavioral level demonstrated that mimicry increases prosocial behavior. However, these previous studies focused on the mimickee. In the present paper, we investigated whether mimickers also become more helpful due to mimicry. In two studies, we have demonstrated that participants, who mimicked expressions of a person shown on a video, donated more money to a charity than participants who did not mimic. Moreover, the processes by which mimicry and prosocial behavior are related largely remain empirically unexamined in existing literature. The results of Study 2 confirmed our hypothesis that affective empathy mediates the relationship between mimicry and prosocial behavior. This suggests that mimicry created an affective empathic mindset, which activated prosocial behaviors directed toward others. Copyright © 2007 John Wiley & Sons, Ltd.
Signal Processing in Normal Pulse Voltammetry by Means of Dedicated Mother Wavelet
Authors: Jakubowska Małgorzata , Kubiak Władysław W. 
Published: October 2007

AbstractIn the work, a new signal processing algorithm is presented and applied for the transformation of the sigmoidal shaped curves, registered in normal pulse voltammetry (NPV), to the peak shaped curves. The method is based on the continuous wavelet transform (CWT) and specially constructed mother wavelet defined using the ideal wave‐shaped curve. Transformation of the signal, elimination of noises and separation of overlapping data can be achieved in one step by means of proposed procedure. The operation and effectiveness of the algorithm is presented using ideal, noised and overlapping simulated curves. The process of simultaneous determination of lead and indium as well as transformation of curves registered for elements' ions: lead, indium, thallium and cadmium is described. The obtained results show substantial improvement of the performance of NPV.
Voltammetric Determination of Xanthine with a Single‐Walled Carbon Nanotube‐Ionic Liquid Paste Modified Glassy Carbon Electrode
Authors: Xiao Fei , Ruan Changping , Li Jiangwen , Liu Lihong , Zhao Faqiong , Zeng Baizhao 
Published: October 2007

AbstractSingle‐walled carbon nanotube (SWNT) and room temperature ionic liquid (i.e., 1‐butyl‐3‐methylimidazolium hexaflourophosphate, BMIMPF6) were used to fabricate paste modified glassy electrode (GCE). It was found that the electrode showed sensitive voltammetric response to xanthine (Xt). The detection limit was 2.0×10−9 M and the linear range was 5.0×10−9 to 5.0×10−6 M. The electrode also displayed good selectivity and repeatability. In the presence of uric acid (UA) and hypoxanthine (Hx) the response of Xt kept almost unchanged. Thus this electrode could find application in the determination of Xt in some real samples. The analytical performance of the BMIMPF6‐SWNT/GCE was demonstrated for the determination of Xt in human serum and urine samples.
Determination of Mercury by Anodic Stripping Voltammetry with a Gold Nanoparticle‐Modified Glassy Carbon Electrode
Authors: Abollino Ornella , Giacomino Agnese , Malandrino Mery , Piscionieri Giuseppina , Mentasti Edoardo 
Published: October 2007

AbstractThe aim of this work is the development of a procedure for the determination of aqueous Hg(II) by anodic stripping voltammetry at a gold nanoparticle‐modified glassy carbon electrode (AuNPs‐GCE). The signal of aqueous Hg(II) was measured in the square wave mode; the effect of potential scan parameters, deposition potential and deposition time on the analytical signal was examined. The supporting electrolyte was 0.06 M HCl. The repeatability, the linearity, the accuracy, the detection limit of the procedure and the interferences of other cations and of anions were evaluated. The performance of the AuNPs‐GCE was compared with those of a solid (SGE) and a film (FGE) gold electrode: the AuNPs‐GCE showed to provide lower detection limits and higher repeatability. The renewable surface permits to eliminate memory effects, to maintain a stable baseline and response, and to avoid frequent mechanical cleaning steps. The applicability of the AuNPs‐GCE for Hg(II) determination in drinking waters, sediments and pharmaceuticals was demonstrated.
Analysis of tetracycline residues in bovine milk by CE‐MS with field‐amplified sample stacking
Authors: Wang Shufang , Yang Ping , Cheng Yiyu 
Published: October 2007

AbstractA rapid, sensitive, and robust CE‐MS method has been developed for the determination of tetracycline, oxytetracycline, and chlortetracycline in milk. Field‐amplified sample stacking with electromigration injection (FASS‐EMI) was used for the online concentration of tetracyclines. The conditions of separation, MS detection, and stacking were systematically optimized. The optimum buffer composition was 35 mM Tris, 1.1% formic acid, 5% methanol, and 15% ACN. By using the online concentration method of field‐enhanced sample stacking (FESI)‐EMI stacking, the sensitivity was increased six‐ to seven‐fold. The RSDs (n = 6) of the relative migration time of tetracyclines were 1.1–1.4% for intraday and 2.4–2.9% for interday. The RSDs (n = 6) of the relative peak area of tetracyclines were 3.2–4.6% for intraday and 4.7–6.1% for interday. The LODs (S/N = 3) were 7.14 ng/mL for tetracycline, 11.4 ng/mL for oxytetracycline, and 14.9 ng/mL for chlortetracycline. The method has been successfully used to analyze tetracyclines residues in bovine milk.
Optimization of the SNR‐resolution tradeoff for registration of magnetic resonance images
Authors: Kale Shoan C. , Lerch Jason P. , Henkelman R. Mark , Chen X. Josette 
Published: October 2007

AbstractImage registration serves many applications in medical imaging, including longitudinal studies, treatment verification, and more recently, morphometry. Registration processing is regularly applied in magnetic resonance (MR) images, where imaging is highly adaptable in capturing soft tissue contrast. To obtain the greatest registration accuracy in MR imaging, the inherent imaging tradeoff between SNR and resolution at a given scan time should be optimized for computational accuracy, rather than human viewing. We investigated this SNR‐resolution tradeoff to optimize registration for digital morphometry. Tradeoff images were simulated from acquired gold standard MR images to emulate a shorter, constant acquisition time, but at the expense of SNR, resolution, or both. The group of images from each tradeoff was nonlinearly registered toward an average atlas producing deformation fields, useful for identifying differences in morphology. The gold standard data were also registered. The deformation fields were used to evaluate registration performance of each tradeoff relative to the gold standard. For fixed scan times, the optimal SNR for registration with MR imaging was found to be ∼20. Image resolution should be adjusted to produce this target voxel SNR when registration is a central processing task. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Glycan modification of the tumor antigen gp100 targets DC‐SIGN to enhance dendritic cell induced antigen presentation to T cells
Authors: Aarnoudse Corlien A. , Bax Marieke , Sánchez‐Hernández Marta , García‐Vallejo Juan J. , van Kooyk Yvette 
Published: October 2007

AbstractDendritic cells (DC) have gained much interest in the field of anticancer vaccine development because of their central function in immune regulation. However, the clinical application of ex vivo cultured DC has significant disadvantages. A vaccine that targets dendritic cells in vivo and enhances antigen presentation would be of great benefit. Because of its DC‐restricted expression pattern, and its function as an antigen uptake receptor, DC‐SIGN is an interesting candidate target structure for human immature DC. Here, we studied whether modification of the melanoma differentiation antigen gp100 with DC‐SIGN‐interacting glycans enhances targeting to human DC. A high‐mannose form of gp100, as protein or as tumor lysate, not only interacted specifically with DC through DC‐SIGN but also resulted in an enhanced antigen presentation to gp100‐specific CD4+ T cells. Our results indicate that glycan modification of tumor antigens to target C‐type lectin receptors, such as DC‐SIGN, is a new way to develop in vivo targeting DC strategies that simultaneously enhance the induction of tumor‐specific T cells. © 2007 Wiley‐Liss, Inc.
Effect of age, birth cohort and period of death on skin melanoma mortality in Spain, 1975 through 2004
Authors: Cayuela Aurelio , Rodríguez‐Domínguez Susana , Vigil Eduardo , Conejo‐Mir Julián Sánchez 
Published: October 2007

AbstractRecent statistics cohort analysis of mortality reveals that skin melanoma rates are dropping in the younger cohorts. Therefore, the aim of this study is to provide up‐to‐date information and to analyze recent changes in skin melanoma mortality trends in Spain during the period of 1975–2004 using joinpoint regression and age–period–cohort models. Between 1975 and 2004, the age‐standardized (overall) mortality rates for skin melanoma increased from 0.3 to 1.3 per 100,000 person‐years for males and from 0.2 to 0.8 per 100,000 person‐years for females, with an estimated annual percentage of change of 4.8 and 4.3%, respectively. In men and women, the best fit was found for the full model, which simultaneously considered the effects of age, period and cohort. The risks among both males and females increased in each successive birth cohort born between 1895 and 1950. Thereafter, the risks declined through the most recent birth cohort born in 1970. Examination of the mortality trends by age group and birth cohort revealed that the recent less rapidly rising (men) or stabilizing (women) age‐adjusted skin melanoma mortality rates in Spain were a result of declining mortality in the younger age groups and more recent birth cohorts. The particularly favorable trends in young people suggest that a further decline in mortality from skin melanoma in Spain is likely to occur within the next few years. © 2007 Wiley‐Liss, Inc.