bluuebunny/crossref_metadata_2025_split huggingface dataset:
Styryl‐Based Compounds as Potential in vivo Imaging Agents for β‐Amyloid Plaques
Authors: Li Qian , Min Jaeki , Ahn Young‐Hoon , Namm Joshua , Kim Eun Min , Lui Rowena , Kim Hye Yun , Ji Yong , Wu Hueizhi , Wisniewski Thomas , Chang Young‐Tae 
Published: August 2007

AbstractA group of styryl‐based neutral compounds has been synthesized in this study for potential use as in vivo imaging agents for β‐amyloid plaques. Of 56 candidates, 14 compounds were found to label β‐amyloid plaques well on Alzheimer's disease (AD) human brain sections in vitro. The binding affinity to β‐amyloid fibrils was then determined by measuring the change in fluorescence intensity. Interestingly, we found that a class of quinaldine‐styryl scaffold compounds displays specific binding to β‐amyloid fibrils. A representative compound, STB‐8, was used in ex vivo and in vivo imaging experiments on an AD transgenic mouse model and demonstrated excellent blood–brain barrier (BBB) permeability and specific staining of the AD β‐amyloid plaques.
Keratanase II‐Catalyzed Synthesis of Keratan Sulfate Oligomers by Using Sugar Oxazolines as Transition‐State Analogue Substrate Monomers: A Novel Insight into the Enzymatic Catalysis Mechanism
Authors: Ohmae Masashi , Sakaguchi Kazuya , Kaneto Taihei , Fujikawa Shun‐ichi , Kobayashi Shiro 
Published: August 2007

AbstractKeratan sulfate (KS) oligomers with well‐defined structures were synthesized by keratanase II (KSase II)‐catalyzed transglycosylation. N‐Acetyllactosamine [Galβ(1→4)GlcNAc; LacNAc] oxazoline derivatives with sulfate groups at the C‐6 (1 a) and both the C‐6 and the C‐6′ (1 b) were prepared as transition‐state analogue substrate monomers for KSase II. Monomer 1 a was effectively oligomerized by the enzyme under weak alkaline conditions, to give alternating 6‐sulfated KS oligomers (2 a) in good yields, and with total control of regioselectivity and stereochemistry. KSase II also recognized 1 b, which provided fully 6‐sulfated KS oligomers (2 b) in good yields under similar conditions. Nonsulfated LacNAc oxazoline was difficult to oligomerize enzymatically. These results imply that the catalysis mechanism of KSase II involves a sugar oxazolinium ion that requires the 6‐sulfate group in the GlcNAc residue not only in hydrolysis of KS chains, but also in oligomerization of oxazoline monomers. This is the first report of KSase II‐catalyzed transglycosylation to form β(1→3)‐glycosidic bond through a substrate‐assisted mechanism.
Differential Selectivity of Natural and Synthetic Aminoglycosides towards the Eukaryotic and Prokaryotic Decoding A Sites
Authors: Kondo Jiro , Hainrichson Mariana , Nudelman Igor , Shallom‐Shezifi Dalia , Barbieri Christopher M. , Pilch Daniel S. , Westhof Eric , Baasov Timor 
Published: August 2007

AbstractThe lack of absolute prokaryotic selectivity of natural antibiotics is widespread and is a significant clinical problem. The use of this disadvantage of aminoglycoside antibiotics for the possible treatment of human genetic diseases is extremely challenging. Here, we have used a combination of biochemical and structural analysis to compare and contrast the molecular mechanisms of action and the structure–activity relationships of a new synthetic aminoglycoside, NB33, and a structurally similar natural aminoglycoside apramycin. The data presented herein demonstrate the general molecular principles that determine the decreased selectivity of apramycin for the prokaryotic decoding site, and the increased selectivity of NB33 for the eukaryotic decoding site. These results are therefore extremely beneficial for further research on both the design of new aminoglycoside‐based antibiotics with diminished deleterious effects on humans, as well as the design of new aminoglycoside‐based structures that selectively target the eukaryotic ribosome.
The Unexpected Versatility of P4S3 as a Building Block in Polymeric Copper Halide Networks: 2,3‐P, 1,2,3‐P and all‐P Coordination
Authors: Biegerl Andreas , Brunner Eike , Gröger Christian , Scheer Manfred , Wachter Joachim , Zabel Manfred 
Published: August 2007

AbstractLayering solutions of P4S3 in CH2Cl2 with solutions of CuCl or CuI in CH3CN gives the coordination polymers (P4S3)3(CuCl)7 (1), (P4S3)2(CuCl)3 (2), (P4S3)(CuI) (3) and (P4S3)(CuI)3 (4), respectively, after slow diffusion. The yellow compounds were characterised by elemental analysis, 31P magic‐angle spinning (MAS) NMR spectroscopy and single‐crystal X‐ray crystallography. The solid‐state structures demonstrate the unexpected ligand versatility of the P4S3 molecule, which interacts through two, three, or even all of the phosphorus atoms with copper according to the nature of the copper halide. Compound 1 has a three‐dimensional network in which linear and cylindrical infinite CuCl subunits coexist with diatomic CuCl building blocks. For the first time, all four P atoms of the P4S3 cage are involved in coordination with metal atoms. The 3D structure of 2 contains stacks of P4S3 that are interconnected by slightly undulated and planar [CuCl]n ribbons. Compound 3 is a one‐dimensional polymer composed of alternating (CuI)2 rings and P4S3 bridges. The structure of 4 consists of undulated [CuI]n layers in which the P4S3 cage functions as a bridge within the layer, as well as a spacer between the layers. The 31P MAS NMR spectra obtained are in good agreement with the solid‐state structures obtained crystallographically. Thus, analytically pure 3 and 4 show singlet peaks that correspond to uncoordinated P and quartets owing to coupling with 63Cu and 65Cu, respectively, whereas that of 1 contains quartets according to all‐P coordination. The spectrum of 2 was obtained from a sample that still contained 40 % of 1.
An Ionically Driven Molecular IMPLICATION Gate Operating in Fluorescence Mode
Authors: Rurack Knut , Trieflinger Christian , Koval'chuck Anton , Daub Jörg 
Published: August 2007

AbstractAn asymmetrically core‐extended boron–dipyrromethene (BDP) dye was equipped with two electron‐donating macrocyclic binding units with different metal ion preferences to operate as an ionically driven molecular IMPLICATION gate. A Na+‐responsive tetraoxa‐aza crown ether (R2) was integrated into the extended π system of the BDP chromophore to trigger strong intramolecular charge transfer (ICT2) fluorescence and guarantee cation‐induced spectral shifts in absorption. A dithia‐oxa‐aza crown (R1) that responds to Ag+ was attached to the meso position of BDP in an electronically decoupled fashion to independently control a second ICT1 process of a quenching nature. The bifunctional molecule is designed in such a way that in the absence of both inputs, ICT1 does not compete with ICT2 and a high fluorescence output is obtained (InA=InB=0→Out=1). Accordingly, binding of only Ag+ at R1 (InA=1, InB=0) as well as complexation of both receptors (InA=InB=1) also yields Out=1. Only for the case in which Na+ is bound at R2 and R1 is in its free state does quenching occur, which is the distinguishing characteristic for the InA=0 and InB=1→Out=0 state that is required for a logic IMPLICATION gate and Boolean operations such as IF‐THEN or NOT.
Multicomponent Dynamic Covalent Assembly of a Rhombicuboctahedral Nanocapsule
Authors: Liu Yong , Liu Xuejun , Warmuth Ralf 
Published: August 2007

AbstractMolecular container compounds have a range of potential applications in chemical and biological sciences, most notably as nanoreactors, drug delivery devices, and storage materials. We report a highly efficient dynamic covalent chemistry approach for the synthesis of covalent rhombicuboctahedral nanocapsule 1 from 14 square‐ and triangular‐shaped molecular components. The nanocapsule is obtained in a one‐pot reaction in high yield and high purity, and has a solvodynamic diameter of 3.9 nm. In our approach, six formyl cavitands and eight 1,3,5‐tris(p‐aminophenyl)benzene molecules are assembled into a molecular rhombicuboctahedron through twenty four newly formed dynamic imine bonds. Binding studies show that 1 encapsulates tetraalkylammonium salts in toluene. We also discuss the growth mechanism of this nanocapsule.
New method for specifying color‐rendering properties of light sources based on feeling of contrast
Authors: Hashimoto Kenjiro , Yano Tadashi , Shimizu Masanori , Nayatani Yoshinobu 
Published: August 2007

Abstract“Visual clarity” or “feeling of contrast” of object colors under illumination is affected significantly by changing color‐rendering property of light source used. Though the feeling of contrast is considered one of the most important characteristics on color‐rendering properties of light sources, it cannot be estimated adequately by using the present Ra method. The new index FCI is proposed for estimating the effect of feeling of contrast quantitatively under any light sources. The FCI is derived using a simple transformation of the gamut area, which is constituted by a specially selected four‐color combination in CIE LAB color space. The FCI correlates well with the illuminance ratio for equal feeling of contrast (or equal visual clarity) on various light sources reported so far. Using the FCI together with the present CIE Ra, the color‐rendering capability of a light source can be well clarified. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 361–371, 2007
Complexity of the color appearance of objects with nonuniform illumination
Authors: Nayatani Yoshinobu , Sakai Hideki 
Published: August 2007

AbstractAn inversion relationship is clarified between lightness and brightness, and also between chroma and colorfulness under nonuniform illumination with different illuminance levels (high and low) within the same visual field. Brightness (or colorfulness) of object color with low lightness (or chroma) under high illuminance level is perceived higher than that of another object color with high lightness (or chroma) under low illuminance level. Two color images are given for showing the inversion phenomena on brightness–lightness and colorfulness–chroma between object colors under different illuminance levels. These color images are useful for making researchers on color understand the differences in concept between brightness and lightness, and also between colorfulness and chroma. In particular, the concept of colorfulness is important, but difficult to understand. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 372–377, 2007
Image‐based spectral reflectance reconstruction using the matrix R method
Authors: Zhao Yonghui , Berns Roy S. 
Published: August 2007

AbstractThe ultimate goal of spectral imaging is to achieve high spectral accuracy, so that the spectral information can be used to calculate colorimetrically accurate images for any combination of illuminant and observer. A new spectral reconstruction method, called the matrix R method, was developed to reconstruct spectral reflectance factor accurately while simultaneously achieving high colorimetric performance for a defined illuminant and observer. The method combines the benefits of both colorimetric and spectral transformations. Tristimulus values were predicted by a colorimetric transformation from multi‐channel camera signals, while spectral reflectance factor was estimated by a spectral transformation from the same signals. The method reconstructed reflectance factor by combining the fundamental stimulus from the predicted tristimulus values with the metameric black from the estimated spectral reflectance, based on the Wyszecki hypothesis. The experimental results verified the new method as a promising technique for building a spectral image database. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 343–351, 2007
Generic device color gamut description
Authors: Zhao Xianfeng 
Published: August 2007

AbstractThis article describes two methods for N‐dimensional device color gamut representation: one is for gamut surface description, the other for gamut volume description. Both methods combine analytical and geometrical approaches. These methods can be applied to any colorant spaces such as 3‐Dimensional RGB or CMY, 4‐Dimensional CMYK, 6‐Dimensional Hexachrome® (CMYKOG), as well as the 14‐Dimensional PANTONE MATCHING SYSTEM®. The N‐Dimensional gamut surface description method divides the gamut surface into many subsurfaces with only two‐colorant variables. The gamut volume description first divides the whole gamut volume into 3D cubes without overlaps; then an analytical, geometrical, or interpolation method can be applied to each cube. Finally, all subgamuts are united to create the whole gamut. The analytical approach or interpolation technology is applied into these methods to predict unknown colors. The result is highly accurate with an average error less than 0.11 ΔEin CIEDE2000 for CMYK space and less than 0.56 ΔEin CIEDE2000 for higher dimensions. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 394–408, 2007
Faithful representation of colours on a CRT monitor
Authors: Yoonessi Ali , Kingdom Frederick A. A. 
Published: August 2007

AbstractA method is described to display faithfully on a CRT monitor the colours of images taken by a calibrated digital camera. A multicoloured “input” image, displayed on a monitor, was photographed with the camera. After correcting the digital image to take into account the gammas of both camera and monitor, the image was redisplayed as an “output” image on the same monitor. An iterative procedure found the linear matrix transformation that minimized the difference between the input and output image RGB values. We compared the efficacy of this method with two conventional methods for displaying photographed images on CRTs: the method of displaying the raw untransformed image, and the method whereby the image is transformed via the CIE common frame of reference. The results of the comparisons suggest that the iterative method produces the most faithful representation of the colours of the original image. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 388–393, 2007
Provenance trails in the Wings/Pegasus system
Authors: Kim Jihie , Deelman Ewa , Gil Yolanda , Mehta Gaurang , Ratnakar Varun 
Published: August 2007

AbstractOur research focuses on creating and executing large‐scale scientific workflows that often involve thousands of computations over distributed, shared resources. We describe an approach to workflow creation and refinement that uses semantic representations to (1) describe complex scientific applications in a data‐independent manner, (2) automatically generate workflows of computations for given data sets, and (3) map the workflows to available computing resources for efficient execution. Our approach is implemented in the Wings/Pegasus workflow system and has been demonstrated in a variety of scientific application domains. This paper illustrates the application‐level provenance information generated Wings during workflow creation and the refinement provenance by the Pegasus mapping
system for execution over grid computing environments. We show how this information is used in answering the queries of the First Provenance Challenge. Copyright © 2007 John Wiley & Sons, Ltd.
Addressing the provenance challenge using ZOOM
Authors: Cohen‐Boulakia Sarah , Biton Olivier , Cohen Shirley , Davidson Susan 
Published: August 2007

AbstractZOOM* UserViews presents a model of provenance for scientific workflows that is simple, generic, and yet sufficiently expressive to answer questions of data and step provenance that have been encountered in a large variety of scientific case studies. In addition, ZOOM builds on the concept of composite step‐classes—or sub‐workflows—which is present in many scientific workflow systems to develop a notion of user views. This paper discusses the design and implementation of ZOOM in the context of the queries posed by the provenance challenge, and shows how user views affect the level of granularity at which provenance information can be seen and reasoned about. Copyright © 2007 John Wiley & Sons, Ltd.
A Semantic Web approach to the provenance challenge
Authors: Golbeck Jennifer , Hendler James 
Published: August 2007

AbstractProvenance is critically important for scientific workflow systems, as it allows users to verify data, repeat experiments, and discover dependencies. The Semantic Web is a natural fit for representing provenance, as it contains explicit support for representing and inferring connections between data and processes, as well as for adding annotations to data. In this article, we present a Semantic Web approach to the Provenance Challenge (Concurrency Computat.: Pract. Exper. 2007; DOI: 10.1002/cpe.1233). We use web services, ontologies, OWL reasoners, triple stores, and the SPARQL query language to implement the workflow, represent the data and the connections within it, and execute queries. We successfully implemented and answered all of the challenge queries. The flexibility of the Semantic Web also makes it quite easy to convert different provenance systems' data representation to a form we can work with. We illustrate this by integrating data from the PASS approach into our system, and successfully executing all of the challenge queries on it as well. Copyright © 2007 John Wiley & Sons, Ltd.
A frequency‐domain approach to the analysis of stability and bifurcations in nonlinear systems described by differential‐algebraic equations
Authors: Traversa F. L. , Bonani F. , Guerrieri S. Donati 
Published: August 2007

AbstractA general numerical technique is proposed for the assessment of the stability of periodic solutions and the determination of bifurcations for limit cycles in autonomous nonlinear systems represented by ordinary differential equations in the differential‐algebraic form. The method is based on the harmonic balance (HB) technique, and exploits the same Jacobian matrix of the nonlinear system used in the Newton iterative numerical solution of the HB equations for the determination of the periodic steady state. To demonstrate the approach, it is applied to the determination of the bifurcation curves in the parameters' space of Chua's circuit with cubic nonlinearity, and to the study of the dynamics of the limit cycle of a Colpitts oscillator. Copyright © 2007 John Wiley & Sons, Ltd.
A time‐delay technique to improve GBW on negative feedback amplifiers
Authors: Alves Luis Nero , Aguiar Rui L. 
Published: August 2007

AbstractThis paper presents a new method to improve the GBW (gain‐bandwidth product) on negative feedback amplifiers. The proposed method is based on the introduction of time‐delay elements in the feedback loop, which can be exploited to retrieve significant bandwidth enhancements. This delayed feedback concept is analyzed, and considerations are presented for first‐order amplifiers, based on theoretical analysis. The concept is simulated and further demonstrated in a practical example using a series‐shunt feedback amplifier with a TL081 operational amplifier (OA) and a 36‐m‐long coaxial cable as a delay element. Measured experimental results show a maximum bandwidth improvement of almost 90%, from a theoretical maximum of 141%. Copyright © 2007 John Wiley & Sons, Ltd.
The CCII+ and the ICCII as basic building blocks in low‐pass filter realizations
Authors: Soliman Ahmed M. 
Published: August 2007

AbstractThree new grounded capacitor current mode low‐pass filters using two inverting second‐generation current conveyor (ICCII) or one double output ICCII are given. The circuits employ the minimum number of passive circuit components, namely two resistors and two capacitors. The circuits are generated from three new voltage mode low‐pass filters realized with the ICCII. A new grounded capacitor CCII+ current mode low‐pass filter is generated from one of the new voltage mode low‐pass filters employing two ICCII−. A new grounded passive component low‐pass filter with independent control on Q and using three ICCII+ is also introduced. Spice simulation results based on using the 0.5 µm CMOS model are included to support the theoretical analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis, Characterisation and Ligand Properties of Novel Bi‐1,2,3‐triazole Ligands
Authors: Monkowius Uwe , Ritter Stefan , König Burkhard , Zabel Manfred , Yersin Hartmut 
Published: August 2007

AbstractThree 1,1′‐disubstituted 4,4′‐bi‐1H‐1,2,3‐triazols [R‐bta; R = Bn (1), Ph (2), CH2COOH (3)] have been synthesised as bidentate, nitrogen‐based ligands by a CuI‐catalysed “click” reaction between 1,3‐butadiyne and organic azides. Their ligand properties were investigated by preparation of the complexes [RuII(R‐bta)3]Cl2 [R = Bn (4), Ph (5), CH2COOH (6)], [(Bn‐bta)CuI(DPEPhos)] (7) [DPEPhos = bis{2‐(diphenylphosphanyl)phenyl} ether] and [(Bn‐bta)ReI(CO)3Cl] (8) following standard reaction procedures. All compounds were analysed by elemental analysis, mass spectrometry and NMR, IR, UV/Vis and luminescence spectroscopy. In addition, the molecular structures of 1–4, 7, and 8 have been determined by X‐ray crystallography. In all complexes the Bn‐bta acts as a bidentate ligand with structural features comparable to the analogous 2,2′‐bipyridine complexes. In their electronic absorption spectra the RuII and ReI complexes exhibit a lowest energy band at around 300 nm, which is substantially higher in energy than in analogous complexes with bpy ligands. All R‐bta ligands yield complexes that are not luminescent in solution or in the solid state, which makes these ligands particularly suited for use as spectator ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Impedance of flexible suction caissons
Authors: Liingaard Morten , Andersen Lars , Ibsen Lars Bo 
Published: August 2007

AbstractThe dynamic response of offshore wind turbines is affected by the properties of the foundation and the subsoil. The aim of this paper is to evaluate the dynamic soil–structure interaction of suction caissons for offshore wind turbines. The investigations include evaluation of the vertical and coupled sliding–rocking vibrations, influence of the foundation geometry and examination on the properties of the surrounding soil. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency‐dependent coefficients corresponding to different degrees of freedom. The dynamic stiffness coefficients for the skirted foundation are evaluated using a three‐dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviours of the foundation are predicted
accurately using the applied model. The analysis has been carried out for different combinations of the skirt length, Poisson's ratio of the subsoil and the ratio of the soil stiffness to the skirt stiffness. Copyright © 2007 John Wiley & Sons, Ltd.