bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Powerful Chiral Counteranion Motif for Asymmetric Catalysis
Authors: García‐García Pilar , Lay Frank , García‐García Patricia , Rabalakos Constantinos , List Benjamin 
Published: May 2009

AbstractRoom to swing a cat: A chiral disulfonimide has been designed as a powerful new motif for asymmetric catalysis. As a first illustration, a highly efficient and enantioselective Mukaiyama aldol reaction has been developed (see scheme). The actual catalyst is proposed to be an N‐silyl imide which is generated in situ.magnified image
A one‐pot, stereoselective synthesis of 2‐ethoxycarbonyl‐substituted 1,3‐dienes and 1,3‐enynes by hydrostannylation–Stille tandem reaction of tributyltin hydride with alkynyl esters and alkenyl or alkynyl halides
Authors: Cai Mingzhong , Fang Xiaoniu , Dai Ruchun , Zha Lingfang 
Published: May 2009

Abstract2‐Ethoxycarbonyl‐substituted 1,3‐dienes and 1,3‐enynes can be stereoselectively synthesized in one pot under mild conditions, in good yields, by the palladium‐catalyzed hydrostannylation of alkynyl esters, followed by Stille coupling with alkenyl or alkynyl halides, respectively. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of query keywords of sports‐related queries using visualization and clustering
Authors: Zhang Jin , Wolfram Dietmar , Wang Peiling 
Published: May 2009

AbstractThe authors investigated 11 sports‐related query keywords extracted from a public search engine query log to better understand sports‐related information seeking on the Internet. After the query log contents were cleaned and query data were parsed, popular sports‐related keywords were identified, along with frequently co‐occurring query terms associated with the identified keywords. Relationships among each sports‐related focus keyword and its related keywords were characterized and grouped using multidimensional scaling (MDS) in combination with traditional hierarchical clustering methods. The two approaches were synthesized in a visual context by highlighting the results of the hierarchical clustering analysis in the visual MDS configuration. Important events, people, subjects, merchandise, and so on related to a sport were illustrated, and relationships among the sports were analyzed. A small‐scale comparative study of sports searches with and without term assistance was conducted. Searches that used search term assistance by relying on previous query term relationships outperformed the searches without the search term assistance. The findings of this study provide insights into sports information seeking behavior on the Internet. The developed method also may be applied to other query log subject areas.
Normal and abnormal anatomy of the cerebellar vermis in midgestational human fetuses
Authors: Kapur Raj P. , Mahony Barry S. , Finch Lisa , Siebert Joseph R. 
Published: May 2009

AbstractBACKGROUND:Evaluation of the cerebellar vermis is an important component of fetal autopsy, but lack of an established approach, inadequate normal anatomic data, and the subtle nature of some cerebellar malformations negatively affect concordance between prenatal ultrasound and autopsy diagnoses.METHODS:Gross anatomy and sagittal histologic sections of vermis from 26 midgestation fetuses with no posterior fossa anomalies detected by prenatal ultrasound or autopsy were examined to establish stage‐specific norms. These were compared to data from three fetuses with prenatal ultrasound diagnoses of hypoplasia or absence of the cerebellar vermis, each of which had no or equivocal gross cerebellar malformation at autopsy.RESULTS:Two findings segregated cases from controls: (1) The ratio of the rostro‐caudal length of the vermis to that of the cerebellar hemispheres was shorter for cases (<0.7), in comparison with controls (0.7–1). (2) The lobules of the vermis, particularly in the posterior lobe, were less arborized, and the nodulus (caudal‐most lobule) was elongated. Prenatal sonograms from the three cases predicted more severe vermis hypoplasia than was evident at autopsy.CONCLUSIONS:Prenatal ultrasound images that suggest moderate‐to‐severe hypoplasia of the cerebellar vermis may reflect relatively subtle malformations, which are recognized histologically by direct comparison with stage‐matched control data. The data in this series and others suggest a somewhat consistent pattern of lobular malformation, which affects the caudal cerebellum, particularly the nodulus, most severely. Rotation of the cerebellum, secondary to an enlarged fourth ventricle, may account for discordance between ultrasound and autopsy findings. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.
Effect of ultra‐strong static magnetic field on bacteria: Application of Fourier‐transform infrared spectroscopy combined with cluster analysis and deconvolution
Authors: Hu Xing , Qiu Zunan , Wang Yerui , She Zichao , Qian Guangren , Ren Zhongming 
Published: May 2009

AbstractA new method based on Fourier‐transform infrared (FTIR) spectroscopy combined with cluster analysis and deconvolution was established to investigate the biological effect of an ultra‐strong static magnetic field (SMF) of 10.0 T on Escherichia coli and Staphylococcus aureus. FTIR spectroscopy was applied to characterize the spectroscopic fingerprints of these bacterial cells with or without the treatment of the SMF. After the calculation, the results of cluster analysis indicated that the SMF had significant effects on E. coli compared with S. aureus, and the effects were reflected by the changes of spectral region of 1500–1200 cm−1. The deconvolution results of this major indication region showed that the composition and conformation of nucleic acid, protein, and fatty acid of E. coli were altered under the magnetic conditions. Bioelectromagnetics 30:500–507, 2009. © 2009 Wiley‐Liss, Inc.
Chemiluminescence from luminol solution after illumination of a 355 nm pulse laser
Authors: Min Lingyue , Wu Xing‐Zheng 
Published: May 2009

AbstractChemiluminescence (CL) on the time scale of microseconds to milliseconds from luminol solution after illumination of a 355 nm pulse laser is reported. It was found that the CL is the emission from 3‐aminophthalate ion (AP*). In CL decay after the pulse laser illumination, a peak was observed from about 200 to 30 µs depending on the laser power and the luminol concentration. It seemed that there was a fast and slow decay process; their kinetics were greatly dependent on the laser power and the luminol concentration. Dissolved oxygen was involved in the CL and played the same role on the whole time scale of microseconds to milliseconds. Involvement of reactive oxygen species such as H2O2, 1O2, O2•− and OH in the CL was examined by adding their scavengers. Experimental results suggested that the possibility of involvement of H2O2 and 1O2 in the CL was low. The CL in time periods less than 50 µs might be related to •OH. The •O2•−‐induced CL increased with time after 50 µs and became dominant on the time scale of milliseconds. The CL was considered to be caused by both the photoionization and type I reaction mechanisms. Copyright © 2009 John Wiley & Sons, Ltd.
Review: Correlations between oxygen affinity and sequence classifications of plant hemoglobins
Authors: Smagghe Benoit J. , Hoy Julie A. , Percifield Ryan , Kundu Suman , Hargrove Mark S. , Sarath Gautam , Hilbert Jean‐Louis , Watts Richard A. , Dennis Elizabeth S. , Peacock W. James , Dewilde Sylvia , Moens Luc , Blouin George C. , Olson John S. , Appleby Cyril A. 
Published: May 2009

AbstractPlants express three phylogenetic classes of hemoglobins (Hb) based on sequence analyses. Class 1 and 2 Hbs are full‐length globins with the classical eight helix Mb‐like fold, whereas Class 3 plant Hbs resemble the truncated globins found in bacteria. With the exception of the specialized leghemoglobins, the physiological functions of these plant hemoglobins remain unknown. We have reviewed and, in some cases, measured new oxygen binding properties of a large number of Class 1 and 2 plant nonsymbiotic Hbs and leghemoglobins. We found that sequence classification correlates with distinct extents of hexacoordination with the distal histidine and markedly different overall oxygen affinities and association and dissociation rate constants. These results suggest strong selective pressure for the evolution of distinct physiological functions. The leghemoglobins evolved from the Class 2 globins and show no hexacoordination, very high rates of O2 binding (∼250 μM−1 s−1), moderately high rates of O2 dissociation (∼5–15 s−1), and high oxygen affinity (Kd or P50 ≈ 50 nM). These properties both facilitate O2 diffusion to respiring N2 fixing bacteria and reduce O2 tension in the root nodules of legumes. The Class 1 plant Hbs show weak hexacoordination (KHisE7 ≈ 2), moderate rates of O2 binding (∼25 μM−1 s−1), very small rates of O2 dissociation (∼0.16 s−1), and remarkably high O2 affinities (P50 ≈ 2 nM), suggesting a function involving O2 and nitric oxide (NO) scavenging. The Class 2 Hbs exhibit strong hexacoordination (KHisE7 ≈ 100), low rates of O2 binding (∼1 μM−1 s−1), moderately low O2 dissociation rate constants (∼1 s−1), and moderate, Mb‐like O2 affinities (P50 ≈ 340 nM), perhaps suggesting a sensing role for sustained low, micromolar levels of oxygen. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 1083–1096, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Simulating gaze attention behaviors for crowds
Authors: Grillon Helena , Thalmann Daniel 
Published: May 2009

AbstractCrowd animation is a topic of high interest which offers many challenges. One of the most important is the trade‐off between rich, realistic behaviors, and computational costs. To this end, much effort has been put into creating variety in character representation and animation. Nevertheless, one aspect still lacking realism in virtual crowd characters resides in their attention behaviors. In this paper, we propose a framework to add gaze attention behaviors to crowd animations. First, we automatically extract interest points from character or object trajectories in pre‐ existing animations. For a given character, we assign a set of elementary scores based on parameters such as distance or speed to all other characters or objects in the scene. We then combine these subscores in an overall scoring function. The scores obtained from this function form a set of gaze constraints that determine where and when each character should look. We finally enforce these constraints with an optimized dedicated gaze Inverse Kinematics (IK) solver. It first computes the displacement maps for the constraints to be satisfied. It then smoothly propagates these displacements over an automatically defined number of frames. We demonstrate the efficiency of our method and our visually convincing results through various examples. Copyright © 2009 John Wiley & Sons, Ltd.
Pressure corrected SPH for fluid animation
Authors: Bao Kai , Zhang Hui , Zheng Lili , Wu Enhua 
Published: May 2009

AbstractWe present a novel pressure correction scheme for the Smoothed Particle Hydrodynamics (SPH) for fluid animation. In the conventional SPH method, equations of state (EOS) are employed to relate the pressure to the particle density. To enforce the volume conservation, high speeds of sound are usually required, which leads to very small time steps and noisy pressure distribution. The problem remains one of the main reasons of numerical instability in SPH. In the paper, a new extra pressure correction scheme is proposed to transport the local pressure disturbance to the neighboring area and no solution of the Poisson equation is required. As a result, smoother pressure distribution and more efficient simulation are achieved. The proposed method has been used to simulate free surface problems. The results demonstrate the validation of the present SPH method. Surface tension and fluid fragmentation can be well handled. Copyright © 2009 John Wiley & Sons, Ltd.
A Targeted Releasable Affinity Probe (TRAP) for In Vivo Photocrosslinking
Authors: Yan Ping , Wang Ting , Newton Gregory J. , Knyushko Tatyana V. , Xiong Yijia , Bigelow Diana J. , Squier Thomas C. , Mayer M. Uljana 
Published: May 2009

AbstractA protein TRAP: The in vivo photocrosslinking of TRAP after its intracellular targeting to a binding sequence on the bait protein stabilizes protein interactions. Because the crosslinker is releasable, simple mass spectrometry can be used to identify the protein binding sites after purification.magnified imageProtein crosslinking, especially coupled to mass‐spectrometric identification, is increasingly used to determine protein binding partners and protein–protein interfaces for isolated protein complexes. The modification of crosslinkers to permit their targeted use in living cells is of considerable importance for studying protein‐interaction networks, which are commonly modulated through weak interactions that are formed transiently to permit rapid cellular response to environmental changes. We have therefore synthesized a targeted and releasable affinity probe (TRAP) consisting of a biarsenical fluorescein linked to benzophenone that binds to a tetracysteine sequence in a protein engineered for specific labeling. Here, the utility of TRAP for capturing protein binding partners upon photoactivation of the benzophenone moiety has been demonstrated in living bacteria and mammalian cells. In addition, ligand exchange of the arsenic–sulfur bonds between TRAP and the tetracysteine sequence to added dithiols results in fluorophore transfer to the crosslinked binding partner. In isolated protein complexes, this release from the original binding site permits the identification of the proximal binding interface through mass spectrometric fragmentation and computational sequence identification.
Synthesis and Application of Peptide Arrays: Quo Vadis SPOT Technology
Authors: Volkmer Rudolf 
Published: May 2009

AbstractHitting the SPOT: In 1992, Ronald Frank published the first seminal paper on simultaneous parallel synthesis of multiple peptides on filter paper. He defined the approach as SPOT synthesis, an easy technique for positionally addressable, parallel chemical synthesis on a membrane support. Here, a basic overview of this technology is presented and a recently published applications are highlighted. At the end, the future of peptide arrays is discussed.magnified image
Selective Antifolates for Chemically Labeling Proteins in Mammalian Cells
Authors: Pedró Rosa Laura E. , Reddy D. Rajasekhar , Queener Sherry F. , Miller Lawrence W. 
Published: May 2009

AbstractAntifolate labels: Molecules that bind specifically and with high affinity to proteins can be developed into powerful tools for chemical biology. The interaction between substituted 5‐benzyl pyrimidines and dihydrofolate reductase can be exploited for chemically labeling fusion proteins in mammalian cells.magnified image
Higher‐order analogues of the Tracy‐Widom distribution and the Painlevé II hierarchy
Authors: Claeys Tom , Krasovsky Igor , Its Alexander 
Published: May 2009

AbstractWe study Fredholm determinants related to a family of kernels that describe the edge eigenvalue behavior in unitary random matrix models with critical edge points. The kernels are natural higher‐order analogues of the Airy kernel and are built out of functions associated with the Painlevé I hierarchy. The Fredholm determinants related to those kernels are higher‐order generalizations of the Tracy‐Widom distribution. We give an explicit expression for the determinants in terms of a distinguished smooth solution to the Painlevé II hierarchy. In addition, we compute large gap asymptotics for the Fredholm determinants. © 2009 Wiley Periodicals, Inc.
Well‐posedness for compressible Euler equations with physical vacuum singularity
Authors: Jang Juhi , Masmoudi Nader 
Published: May 2009

AbstractAn important problem in the theory of compressible gas flows is to understand the singular behavior of vacuum states. The main difficulty lies in the fact that the system becomes degenerate at the vacuum boundary, where the characteristic speeds u ± c coincide and have unbounded spatial derivative since c behaves like x1/2 close to the boundary. In this paper, we overcome this difficulty by presenting a new formulation and new energy spaces. We establish the local‐in‐time well‐posedness of one‐dimensional compressible Euler equations for isentropic flows with the physical vacuum singularity in some spaces adapted to the singularity. © 2009 Wiley Periodicals, Inc.
Neoepitopes reveal the features of type II collagen cleavage and the identity of a collagenase involved in the transformation of the epiphyses anlagen in development
Authors: Lee Eunice R. , Lamplugh Lisa , Kluczyk Beata , Leblond Charles P. , Mort John S. 
Published: May 2009

AbstractIn long bone development, the evolution of the cartilaginous anlagen into a secondary ossification center is initiated by the formation of canals. The excavation to create the canals is achieved through lysis of the two major cartilage components, aggrecan, and the type II collagen (COL2) fibril. The present study examines the lysis of the fibril. Because it is known that matrix metalloproteinases (MMPs) cleave COL2 in vitro at the Gly775‐Leu776 bond, it has been reasoned that, if such cleavage is detected in relation to the canals, it can be concluded that a collagenase is involved. Furthermore, because MMPs undergo change in domain structure with activation resulting in propeptide domain loss then, if such a loss is revealed in relation to the cleavage of COL2, this MMP is likely involved. The collective findings reveal that COL2 is attacked at the afore‐described susceptible peptide bond at the surface of cartilage canals and, that MMP‐13 cleaves it. Developmental Dynamics 238:1547–1563, 2009. © 2009 Wiley‐Liss, Inc.
In vitro organogenesis from undifferentiated cells in Xenopus
Authors: Asashima Makoto , Ito Yuzuru , Chan Techuan , Michiue Tatsuo , Nakanishi Mio , Suzuki Kan , Hitachi Keisuke , Okabayashi Koji , Kondow Akiko , Ariizumi Takashi 
Published: May 2009

AbstractAmphibians have been used for over a century as experimental animals. In the field of developmental biology in particular, much knowledge has been accumulated from studies on amphibians, mainly because they are easy to observe and handle. Xenopus laevis is one of the most intensely investigated amphibians in developmental biology at the molecular level. Thus, Xenopus is highly suitable for studies on the mechanisms of organ differentiation from not only a single fertilized egg, as in normal development, but also from undifferentiated cells, as in the case of in vitro organogenesis. Based on the established in vitro organogenesis methods, we have identified many genes that are indispensable for normal development in various organs. These experimental systems are useful for investigations of embryonic development and for advancing regenerative medicine. Developmental Dynamics 238:1309–1320, 2009. © 2009 Wiley‐Liss, Inc.
Finding partners: How BMPs select their targets
Authors: Blitz Ira L. , Cho Ken W.Y. 
Published: May 2009

AbstractThe bone morphogenetic protein (BMP) signaling pathway is a conserved and evolutionarily ancient regulatory module affecting a large variety of cellular behaviors. The evolutionary flexibility in using BMP responses presumably arose by co‐option of a canonical BMP signaling cascade to regulate the transcription of diverse batteries of target genes. This begs the question of how seemingly interchangeable BMP signaling components elicit widely different outputs in different cell types, an important issue in the context of understanding how BMP signaling integrates with gene regulatory networks to control development. Because a molecular understanding of how BMP signaling activates different batteries of target genes is an essential prerequisite to comprehending the roles of BMPs in regulating cellular responses, here we review the current knowledge of how BMP‐regulated target genes are selected by the signal transduction machinery. We highlight recent studies suggesting the evolutionary conservation of BMP target gene regulation signaling by Schnurri family zinc finger proteins. Developmental Dynamics 238:1321–1331, 2009. © 2009 Wiley‐Liss, Inc.
Stabilization of {RuNO}6 and {RuNO}7 States in [RuII(trpy)(bik)(NO)]n+ {trpy = 2,2′:6′,2″‐terpyridine, bik = 2,2′‐bis(1‐methylimidazolyl) ketone} – Formation, Reactivity, and Photorelease of Metal‐Bound Nitrosyl
Authors: De Prinaka , Sarkar Biprajit , Maji Somnath , Das Atanu Kumar , Bulak Ece , Mobin Shaikh M. , Kaim Wolfgang , Lahiri Goutam Kumar 
Published: May 2009

AbstractRuthenium nitrosyl complexes have been isolated in the {RuNO}6 and {RuNO}7 configurations, employing the following reaction pathway for [Ru(trpy)(bik)(X)]n+: X = Cl–, [1](ClO4) → X = CH3CN, [2](ClO4)2 → X = NO2–, [3](ClO4) → X = NO+, [4](ClO4)3 → X = NO·, [4](ClO4)2. The single‐crystal X‐ray structures of [1](ClO4)·(C6H6)·H2O, [2](ClO4)2·H2O, and [3](ClO4)·H2O have been determined. The successive NO+/NO· (reversible) and NO·/NO– (irreversible) reduction processes of [4]3+ appear at +0.36 and –0.40 V vs. SCE, respectively. While the ν(C=O) frequency of the bik ligand at about 1630 cm–1 is largely invariant on complexation and reduction, the ν(NO) frequency for the {RuNO}6 state in [4]3+ at 1950 cm–1 shifts to about 1640 cm–1 on one‐electron reduction to the {RuNO}7 form in [4]2+, reflecting the predominant NO+ → NO· character of this electron transfer. However, a sizeable contribution from ruthenium with its high spin‐orbit coupling constant to the singly occupied molecular orbital (SOMO) is apparent from the enhanced g anisotropy in the EPR spectrum [4]2+ (g1 = 2.015, g2 = 1.995, g3 = 1.881; gav = 1.965; Δg = 0.134). The {RuNO}6 unit in [4]3+ reacts with OH– via an associatively activated process (ΔS# = –126.5 ± 2 J K–1 mol–1) with a second‐order rate constant of k = 3.3 × 10–2 M–1 s–1, leading to the corresponding nitro complex [3]+. On exposure to light both {RuNO}6 and {RuNO}7 in [4]3+ and [4]2+ undergo Ru–NO photocleavage in CH3CN via the formation of [Ru(trpy)(bik)(CH3CN)]2+, [2]2+. The rate of photocleavage of the RuII–NO+ bond in [4]3+ (kNO, 8.57 ×10–1 s–1, t1/2 = 0.80 s) is found to be much faster than that of the RuII–NO· bond in [4]2+, [kNO·, 5.45 × 10–4 s–1, t1/2 = 21.2 min (= 1272 s)]. The photoreleased nitrosyl can be trapped as an Mb‐NO adduct.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Tuning Electronic Properties of Biomimetic [2Fe‐2S] Clusters by Ligand Variations
Authors: Ballmann Joachim , Dechert Sebastian , Demeshko Serhiy , Meyer Franc 
Published: May 2009

AbstractElectronic effects of coordinated thiolate ligands on biomimetic [2Fe‐2S] cluster cores have been examined by using three 2,2′‐dithiobiphenyl chelate ligands that differ by the backbone substituents (Cl, H, tBu). While the X‐ray crystallographic analyses show little structural variation and Mössbauer spectra reveal only subtle differences for the three complexes 1–3, superconducting quantum interference device (SQUID) magnetic data and UV/Vis spectroscopy in solution demonstrate that the different ligand environments cause significant electronic changes in the cluster cores. In particular, potentials for the one‐electron reduction differ drastically over almost 0.5 V among the series. Due to the tight chelate arrangement, the reduced mixed‐valent species are relatively stable on the electrochemical time scale, which is unusual for all‐S‐ligated [2Fe‐2S] systems. The set of new complexes 1–3 thus provides a valuable platform to investigate reactivity patterns and the effect of electronic variations in biomimetic [2Fe‐2S] clusters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)