bluuebunny/crossref_metadata_2025_split huggingface dataset:
Covalent and Non‐covalent Chemical Modification of Multi‐walled Carbon Nanotubes with Tetra‐(4‐hydroxylphenyl)porphyrin and Its Complexes
Authors: Zhao Hongbin , Wang Hongke , Chang Hui , Qiu Shijun , Deng Biyun , Liao Junxu 
Published: September 2011

AbstractMulti‐walled carbon nanotubes (MWNTs) were covalently and non‐covalently functionalized with tetra‐(4‐hydroxylphenyl) porphyrin (THPPH2) and its complexes (ZnTHPP) forming dispersible nanohybrids in organic solution. The morphology of the nanohybrids was observed with transmission electron microscopy. The structure of the product was characterized by FT‐IR, UV‐Vis spectrophotometer, fluorescence spectroscopy and thermogravimetric analysis. The photo‐induced electron‐transfer process of the nanohybrids in organic solution was also revealed.
A One‐pot Green Synthesis of Alkylidenesuccinimides
Authors: Yan Lin , Yang Wenguo , Li Lixin , Shen Yang , Jiang Zhiyong 
Published: September 2011

AbstractA mild and facile Wittig reaction between N‐substituted maleimides and aldehydes has been developed. Various synthetically valuable alkylidenesuccinimides were obtained from this one‐pot reaction in high yields (up to 99%). The product was obtained by simple filtration and no extra purification was necessary. Ethanol, an environment‐benign solvent, was found to be a suitable reaction medium.
A New Luminescent Ruthenium(II) Polypyridine‐derived Dipicolylamine Complex as a Sensor for Cu2+ Ions
Authors: Li Xianghong , Chen Yuanbing , Meng Jiahe , Lü Kangle , Zhang Aiqing , Zhang Bingguang 
Published: September 2011

AbstractA chemo‐sensor [Ru(bpy)2(bpy‐DPF)](PF6)2 (1) (bpy=2,2′‐bipyridine, bpy‐DPF=2,2′‐bipyridyl‐4,4′‐bis(N,N‐di(2‐picolyl))formylamide) for Cu2+ using di(2‐picolyl)amine (DPA) as the recognition group and a ruthenium(II) complex as the reporting group was synthesized and characterized successfully. It demonstrates a high selectivity and efficient signaling behavior only for Cu2+ with obvious red‐shifted MLCT (metal‐to‐ligand charge transfer transitions) absorptions and dramatic fluorescence quenching compared with Zn2+ and other metal ions.
Emission Color Tuning with Polymer Molecular Weight for Dyes of 4‐Dicyanomethylene‐2‐methyl‐6‐{4‐[(2‐hydroxyethyl)(methyl)amino]styryl}‐4H‐pyran
Authors: Zhang Jinfeng , Wu Jincai 
Published: September 2011

AbstractA series of novel polylactide (PLA) polymers were synthesized initiated by 4‐dicyanomethylene‐2‐methyl‐6‐{4‐[(2‐hydroxyethyl)(methyl)amino]styryl}‐4H‐pyran (DCM) with Sn(Oct)2 as catalyst. The color and emission of the polymer can be tuned just with polymer molecular weight.
Ab initio Study of Mechanism of Cycloaddition Reaction between Germylene Silylene (H2GeSi:) and Acetone
Authors: Lu Xiuhui , Han Junfeng , Li Yongqing , Wang Zhina 
Published: September 2011

AbstractThe mechanism of the cycloaddition reaction between singlet germylene silylene (H2GeSi:) and acetone has been investigated with CCSD(T)/6‐31G*//MP2/6‐31G* method. From the potential energy profile, we could predict that the reaction has two competitive dominant reaction channels. The present rule of this reaction is that the [2+2] cycloaddition reaction of the two (‐bonds in germylene silylene and acetone generates a four‐membered ring silylene with Ge. Because of the unsaturated property of Si atom in the four‐membered ring silylene with Ge, it could further react with acetone, resulting in the generation of a bis‐heterocyclic compound with Si and Ge. Simultaneously, the ring strain of the four‐membered ring silylene with Ge makes it isomerize to a twisted four‐membered ring product.
Intercomparison of performance of RF coil geometries for high field mouse cardiac MRI
Authors: Constantinides Christakis , Angeli S. , Gkagkarellis S. , Cofer G. 
Published: September 2011

AbstractMultiturn spiral surface coils are constructed in flat and cylindrical arrangements and used for high field (7.1 T) mouse cardiac MRI. Their electrical and imaging performances, based on experimental measurements, simulations, and MRI experiments in free space, and under phantom, and animal loading conditions, are compared with a commercially available birdcage coil. Results show that the four‐turn cylindrical spiral coil exhibits improved relative SNR (rSNR) performance to the flat coil counterpart, and compares fairly well with a commercially available birdcage coil. Phantom experiments indicate a 50% improvement in the SNR for penetration depths ≤6.1 mm from the coil surface compared to the birdcage coil, and an increased penetration depth at the half‐maximum field response of 8 mm in the four‐spiral cylindrical coil case, in contrast to 2.9 mm in the flat four‐turn spiral case. Quantitative comparison of the performance of the two spiral coil geometries in anterior, lateral, inferior, and septal regions of the murine heart yield maximum mean percentage rSNR increases of the orderof 27–167% in vivo postmortem (cylindrical compared to flat coil). The commercially available birdcage outperforms the cylindrical spiral coil in rSNR by a factor of 3–5 times. The comprehensive approach and methodology adopted to accurately design, simulate, implement, and test radiofrequency coils of any geometry and type, under any loading conditions, can be generalized for any application of high field mouse cardiac MRI. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38: 236–252, 2011.
Biomolecular surface construction by PDE transform
Authors: Zheng Qiong , Yang Siyang , Wei Guo‐Wei 
Published: September 2011

SUMMARYThis work proposes a new framework for the surface generation based on the partial differential equation (PDE) transform. The PDE transform has recently been introduced as a general approach for the mode decomposition of images, signals, and data. It relies on the use of arbitrarily high‐order PDEs to achieve the time–frequency localization, control the spectral distribution, and regulate the spatial resolution. The present work provides a new variational derivation of high‐order PDE transforms. The fast Fourier transform is utilized to accomplish the PDE transform so as to avoid stringent stability constraints in solving high‐order PDEs. As a consequence, the time integration of high‐order PDEs can be done efficiently with the fast Fourier transform. The present approach is validated with a variety of test examples in two‐dimensional and three‐dimensional settings. We explore the impact of the PDE transform parameters, such as the PDE order and propagation time, on the quality of resulting surfaces. Additionally, we utilize a set of 10 proteins to compare the computational efficiency of the present surface generation method and a standard approach in Cartesian meshes. Moreover, we analyze the present method by examining some benchmark indicators of biomolecular surface, that is, surface area, surface‐enclosed volume, solvation free energy, and surface electrostatic potential. A test set of 13 protein molecules is used in the present investigation. The electrostatic analysis is carried out via the Poisson–Boltzmann equation model. To further demonstrate the utility of the present PDE transform‐based surface method, we solve the Poisson–Nernst–Planck equations with a PDE transform surface of a protein. Second‐order convergence is observed for the electrostatic potential and concentrations. Finally, to test the capability and efficiency of the present PDE transform‐based surface generation method, we apply it to the construction of an excessively large biomolecule, a virus surface capsid. Virus surface morphologies of different resolutions are attained by adjusting the propagation time. Therefore, the present PDE transform provides a multiresolution analysis in the surface visualization. Extensive numerical experiment and comparison with an established surface model indicate that the present PDE transform is a robust, stable, and efficient approach for biomolecular surface generation in Cartesian meshes. Copyright © 2011 John Wiley & Sons, Ltd.
A Theoretical Study of the 3d‐M(smif)2Complexes: Structure, Magnetism, and Oxidation States
Authors: Hachmann Johannes , Frazier Brenda A. , Wolczanski Peter T. , Chan Garnet Kin‐Lic 
Published: September 2011

AbstractWe carry out a theoretical investigation of the recently reported M(smif)2series1, 2and find a number of interesting phenomena. These include complex potential energy surfaces with near‐degenerate stationary points, low‐lying states, non‐trivial electron configurations, as well as non‐innocent ligand behavior. The M(smif)2exhibit a delicate balance between geometry and electronic structure, which has implications not only for their reactivity but also for controlling their properties through ligand design. We address methodological issues and show how conceptual quantities such as oxidation states and electronic configurations can be extracted through a simple analysis of the electron and spin densities—without a complicated examination of the underlying orbitals.
The Resonance Raman Spectra of Spheroidene Revisited with a First‐Principles Approach
Authors: Boereboom Jelle M. , van Hemert Marc C. , Neugebauer Johannes 
Published: September 2011

AbstractThe resonance Raman (RR) spectra of different configurations of spheroidene are calculated by means of quantum chemical methods to investigate the nature of the cis configuration of this carotenoid molecule in the photosynthetic reaction center (RC) of the purple bacterium Rhodobacter sphaeroides. For validation of our methodology, we also calculate the spectrum of the all‐trans structure present in the light‐harvesting complexes of this bacterium. While former theoretical resonance Raman studies only considered truncated models of spheroidene, we report on calculations employing the full pigment here. The calculated frequencies for the all‐trans configuration are in good agreement with former experimental and simulated data. Among the possible cis structures, the 15,15′‐cis configuration shows a RR spectrum that is in best agreement with the experimental spectrum of spheroidene in the RC. In order to assess model truncation effects, we compare calculations for the full spheroidene molecule to those for the truncated model. While the main features can already be found in the latter, the full model leads to considerably different intensities in the region around 1150 cm−1, which improve the agreement with experiment. A slight mismatch for the vibrational frequencies in the CC stretch region is investigated by considering a model for spheroidene in the binding pocket comprising more than 500 atoms in total. The results do not lead to improved agreement with experiment, in contrast to the simpler strategy of introducing constraints in the structural optimization of a truncated spheroidene model. The calculated RR spectrum of the 13,14‐cis configuration shows additional features which can also be identified in the experimental RR spectrum. This shows that the most likely cis structure is the 15,15′‐cis configuration. Besides this, the 13,14‐cis configuration remains a candidate for an additional spheroidene structure in the RC of Rhodobacter sphaeroides mutant R26.
Improved flow cytometric detection of ZAP‐70 in chronic lymphocytic leukemia using experimentally optimized isotypic control antibodies
Authors: Preobrazhensky Sergey N. , Szankasi Philippe , Bahler David W. 
Published: September 2011

AbstractIntroduction:Expression of ZAP‐70 by chronic lymphocytic leukemia (CLL) is associated with more aggressive disease and can help differentiate CLL using mutated immunoglobulin heavy chain variable genes (VH) from cases expressing unmutated VH genes. However, flow cytometric detection of ZAP‐70 in CLL shows considerable variability and may be of questionable significance because most laboratories cannot correlate their results to clinical outcome or VH mutational data.Methods:Seventy cases of CLL were evaluated for ZAP‐70 using a previously optimized staining procedure and two different methods to eliminate nonspecific background staining. One method, not previously reported, used isotypic control antibodies, where the concentrations were adjusted/optimized so that normal B‐cells stained negatively for ZAP‐70. The other used ZAP‐70 stained peripheral blood B‐cells from normal donors. The percentages of ZAP‐70 stained CLL cells above the two thresholds were compared.Results:Concentrations of isotypic control antibodies had to be increased from manufacture's recommendations to insure normal B‐cells were ZAP‐70 negative. ZAP‐70 levels among the CLL cases formed a bimodal distribution using the optimized isotypic control threshold, with 30 having low values (0–32% positive) and 40 high values (60–99% positive). In contrast, a continuous distribution was obtained with the ZAP‐70 stained B‐cell threshold. VH mutational status strongly correlated with the optimized control values as 29/30 low ZAP‐70 cases had mutated VH genes and 37/40 high ZAP‐70 cases used unmutated VH genes.Conclusions:Use of an optimized isotypic control threshold could increase the reliability of flow based ZAP‐70 detection and correlates well with VH mutational status. © 2011 International Clinical Cytometry Society
Haptic processing in newborns of depressed and nondepressed mothers
Authors: Jouen François , Sann Coralie , Molina Michèle 
Published: September 2011

AbstractThis study was conducted to compare how newborns of depressed mothers and newborns of nondepressed mothers gather tactile information about texture. Spontaneous manual activity on objects with a smooth or rough texture was recorded in 20 newborns born of mothers with a high risk of depression or a low risk of depression. An important result of the present study is that texture‐based modulation of hand‐pressing frequency was observed in both neonates born of depressed mothers and neonates born of nondepressed mothers. Moreover, hand‐pressing frequency did not depend on the pressure exerted on the object, since all neonates displayed comparable pressure on the held object. Lastly, the results revealed that newborns of depressed mothers held the rough object twice as long as newborns of nondepressed mothers. These results are analyzed in reference to deregulated biochemical functions in neonates born of mothers with a high risk of depression. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:451–459, 2012.
Nerve growth factor induces cell cycle arrest of astrocytes
Authors: Cragnolini Andrea B. , Volosin Marta , Huang Yangyang , Friedman Wilma J. 
Published: September 2011

AbstractNeurotrophins can influence multiple cellular functions depending on the cellular context and the specific receptors they interact with. These neurotrophic factors have been extensively studied for their ability to support neuronal survival via Trk receptors and to induce apoptosis via the p75NTR. However, the p75NTR is also detected on cell populations that do not undergo apoptosis in response to neurotrophins. In particular, the authors have detected p75NTR expression on astrocytes during development and after seizure‐induced injury. In this study, the authors investigated the role of Nerve growth factor (NGF) in regulating astrocyte proliferation and in influencing specific aspects of the cell cycle. The authors have demonstrated that NGF prevents the induction of cyclins and their association with specific cyclin‐dependent kinases, and thereby prevents progression through the G1 phase of the cell cycle. Since the authors have previously shown that p75NTR but not TrkA, is expressed in astrocytes, these data suggest that activation of p75NTR promotes withdrawal of astrocytes from the cell cycle, which may have important consequences during development and after injury. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 766–776, 2012
Live imaging of endogenous periodic tryptophan protein 2 gene homologue during zebrafish development
Authors: Jayasena Chathurani S. , Trinh Le A. , Bronner Marianne 
Published: September 2011

AbstractYeast Periodic tryptophan protein 2 gene (Pwp2) is involved in ribosome biogenesis and has been implicated in regulation of the cell cycle in yeast. Here, we report a zebrafish protein‐trap line that produces fluorescently tagged Periodic tryptophan protein 2 gene homologue (Pwp2h) protein, which can be dynamically tracked in living fish at subcellular resolution. We identified both full‐length zebrafish Pwp2h and a short variant. The expression results show that Pwp2h is present in numerous sites in the early developing embryo, but later is restricted to highly proliferative regions, including the forebrain ventricular zone and endoderm‐derived organs in the early larval stage. At the subcellular level, Pwp2h protein appears to be localized to the region of the nucleolus consistent with its presumed function in ribosomal RNA synthesis. This Pwp2h protein trap line offers a powerful tool to study the link between ribosome biogenesis and cell cycle progression during vertebrate development. Developmental Dynamics 240:2578–2583, 2011. © 2011 Wiley Periodicals, Inc.
Tissue interaction is required for glenoid fossa development during temporomandibular joint formation
Authors: Wang Ying , Liu Chao , Rohr Joseph , Liu Hongbing , He Fenglei , Yu Jian , Sun Cheng , Li Lu , Gu Shuping , Chen YiPing 
Published: September 2011

AbstractThe mammalian temporomandibular joint (TMJ) develops from two distinct mesenchymal condensations that grow toward each other and ossify through different mechanisms, with the glenoid fossa undergoing intramembranous ossification while the condyle being endochondral in origin. In this study, we used various genetically modified mouse models to investigate tissue interaction between the condyle and glenoid fossa during TMJ formation in mice. We report that either absence or dislocation of the condyle results in an arrested glenoid fossa development. In both cases, glenoid fossa development was initiated, but failed to sustain, and became regressed subsequently. However, condyle development appears to be independent upon the presence of the forming glenoid fossa. In addition, we show that substitution of condyle by Meckel's cartilage is able to sustain glenoid fossa development. These observations suggest that proper signals from the developing condyle or Meckel's cartilage are required to sustain the glenoid fossa development. Developmental Dynamics 240:2466–2473, 2011. © 2011 Wiley‐Liss, Inc.
CD4+Foxp3+ regulatory T cells suppress γδ T‐cell effector functions in a model of T‐cell‐induced mucosal inflammation
Authors: Yurchenko Ekaterina , Levings Megan K. , Piccirillo Ciriaco A. 
Published: September 2011

AbstractCD4+CD25+Foxp3+ regulatory T (TREG) cells are critical mediators of peripheral immune tolerance, and abrogation of their function provokes a variety of autoimmune and inflammatory states including inflammatory bowel disease. In this study, we investigate the functional dynamics of TREG‐cell responses in a CD4+ T‐cell‐induced model of intestinal inflammation in αβ T‐cell‐deficient (TCR‐β−/−) hosts to gain insights into the mechanism and cellular targets of suppression in vivo. We show that CD4+ T effector cell transfer into T‐cell‐deficient mice rapidly induces mucosal inflammation and colitis development, which is associated with prominent Th1 and Th17 responses. Interestingly, we unveil a prominent role for resident γδ T cells in mucosal inflammation as they promote Th1 and particularly Th17 responses in the early phase of inflammation, thus exacerbating colitis development. We further demonstrate that CD4+CD25+Foxp3+ TREG cells readily inhibit these responses and mediate disease protection, which correlates with their accumulation in the draining LN and lamina propria. Moreover, TREG cells can directly suppress γδ T‐cell expansion and cytokine production in vitro and in vivo, suggesting a pathogenic role of γδ T cells in intestinal inflammation. Thus, functional alterations in TREG cells provoke dysregulated CD4+ and γδ T‐cell responses to commensal antigens in the intestine.
Recording the Reaction Process of Loop‐Mediated Isothermal Amplification (LAMP) by Monitoring the Voltammetric Response of 2′‐Deoxyguanosine 5′‐Triphosphate
Authors: Zhang Xuzhi , Qu Keming , Li Qiufen , Cui Zhengguo , Zhao Jun , Sun Xuemei 
Published: September 2011

AbstractWe describe here a novel strategy for recording the reaction process of loop‐mediated isothermal amplification (LAMP) by monitoring the voltammetric response of 2′‐deoxyguanosine 5′‐triphosphate (dGTP). Unlike the other three kinds of reactive substrates for DNA synthesis in LAMP reaction, dGTP exhibits sensitive voltammetric response at the carbon nanotube array electrode. When the LAMP reaction occurs, the concentration of dGTP decreases accordingly, bringing forth the decrease of the anodic peak current (ipa). In inversion, the decrease of the ipa of dGTP was used to characterize the reaction process of LAMP. The relationships among the LAMP reaction time, the initial quantity of template DNA and the value change of the ipa were studied. The results indicate that the protocol integrated LAMP and voltammetric techniques can be used for not only qualitative gene discrimination but also quantitative gene assay in a wide range. The malB gene extracted from common strains of Escherichia coli cells was tested as a model. The detecting results of LAMPs obtained by voltammetric method were in good agreement with those by optical‐based methods (gel electrophoresis and fluorescent dye).
Ion‐Selective Electrodes – The Early Years
Authors: Durst Richard A. 
Published: September 2011

AbstractAs we near the 50th anniversary of the development of modern ion‐selective electrodes (ISEs), the Matrafüred Conference seemed to be the ideal venue to reminisce about the early years, since Hungary is generally regarded as the birthplace of these new electrodes. Those of us, who worked with ISEs in the 1960s and ′70s, can recall the excitement of discovery existing at the time. In this reminiscence, I shall first provide a few vignettes of the leaders in the early years followed by a description of some of my personal research to demonstrate the variety of novel approaches open to investigators of that era.
Peptide mapping using capillary electrophoresis offline coupled to matrix‐assisted laser desorption ionization time of flight mass spectrometry
Authors: Bachmann Stefan , Bakry Rania , Huck Christian W. , Polato Fabio , Corradini Danilo , Bonn Günther K. 
Published: September 2011

AbstractThis article reports the results of a study carried out to evaluate the offline hyphenation of capillary zone electrophoresis with matrix‐assisted lased desorption ionization time of flight mass spectrometry (MALDI‐TOF‐MS) for the analysis of low‐abundant complex samples, represented by the tryptic phosphorylated peptides of phosphoproteins, such as α‐casein, β‐casein, and fetuin. The proposed method employs a latex‐coated capillary and consists in the online preconcentration of the tryptic peptides by a pH‐mediated stacking method, their separation by capillary zone electrophoresis, and subsequent deposition of the separated analytes onto a MALDI target for their MS analysis. The online preconcentration method allows loading a large sample volume (∼150 nL), which is introduced into the capillary after the hydrodynamic injection of a short plug of 1.0 M ammonium hydroxide solution and is sandwiched between two plugs of the acidic background electrolyte solution (BGE) filling the capillary. The sample spotting of the separated analytes onto the MALDI target is performed either during or postseparation using an automatic spotting device connected to the exit of the separation capillary. The proposed method allows the separation and identification of multiphosphorylated peptides from other peptides and enables their identification at femtomole level with improved efficiency compared with LC approaches hyphenated to MS.