bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unphosphorylated STAT3 modulates alpha7 nicotinic receptor signaling and cytokine production in sepsis
Authors: Peña Geber , Cai Bolin , Liu Jun , van der Zanden Esmerij P. , Deitch Edwin A. , de Jonge Wouter J. , Ulloa Luis 
Published: July 2010

AbstractThe role of STAT3 in infectious diseases remains undetermined, in part because unphosphorylated STAT3 has been considered an inactive protein. Here, we report that unphosphorylated STAT3 contributes to cholinergic anti‐inflammation, prevents systemic inflammation, and improves survival in sepsis. Bacterial endotoxin induced STAT3 tyrosine phosphorylation in macrophages. Both alpha7 nicotinic receptor (alpha7nAChR) activation and inhibition of JAK2 blunt STAT3 phosphorylation. Inhibition of STAT3 phosphorylation mimicked the alpha7nAChR signaling, inhibiting NF‐κB and cytokine production in macrophages. Transfection of macrophages with the dominant‐negative mutant STAT3F, to prevent its tyrosine phosphorylation, reduced TNF production but did not prevent the alpha7nAChR signaling. However, inhibition of STAT3 protein expression enhanced cytokine production and abrogated alpha7nAChR signaling. Alpha7nAChR controls TNF production in macrophages through a mechanism that requires STAT3 protein expression, but not its tyrosine phosphorylation. In vivo, inhibition of STAT3 tyrosine phosphorylation by stattic prevented systemic inflammation and improved survival in experimental sepsis. Stattic also prevented the production of late mediators of sepsis and improved survival in established sepsis. These results reveal the immunological implications of tyrosine‐unphosphorylated STAT3 in infectious diseases.
Helical Nanostructures of an Optically Active Metal‐Free Porphyrin with Four Optically Active Binaphthyl Moieties: Effect of Metal–Ligand Coordination on the Morphology
Authors: Lu Jitao , Wu Lizhen , Jiang Jianzhuang , Zhang Xiaomei 
Published: July 2010

AbstractAn optically active metal‐free porphyrin (1) with four chiral binaphthyl units attached at the meso‐phenyl substituents through crown ether moieties has been designed, synthesized, and characterized. Its self‐assembly behavior in the absence and presence of K+ was comparatively investigated by electronic absorption and circular dichroism (CD) spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM), and energy‐dispersive X‐ray (EDX) spectroscopy. In the absence of K+, metal‐free porphyrin self‐assembles into nanoparticles depending mainly on the van der Waals interaction among neighboring metal‐free molecules. In the presence of K+, additionally formed metal–ligand K–Ocrown coordination bonds between K+ and crown units of (R)‐ and (S)‐1 molecules, together with chiral discrimination of chiral side chains and intermolecular van der Waals interactions, induce a right‐handed and left‐handed helical arrangement in a stack of (R)‐ and (S)‐1 molecules, respectively, with an ordered “head‐to‐tail” internal molecular arrangement. This then further hierarchically self‐assembles into highly ordered fibrous nanostructures with a helicity opposite to that of the original porphyrin stack. This clearly reveals the effect of the metal–ligand coordination bonding interaction on the morphology and handedness of self‐assembled nanostructures.
Silica–MOF Composites as a Stationary Phase in Liquid Chromatography
Authors: Ameloot Rob , Liekens Anuschka , Alaerts Luc , Maes Michael , Galarneau Anne , Coq Bernard , Desmet Gert , Sels Bert F. , Denayer Joeri F. M. , De Vos Dirk E. 
Published: July 2010

AbstractMetal‐organic framework materials (MOFs) are a class of microporous and crystalline materials with great potential for adsorption‐based separations. Harnessing the separation ability of these materials in high‐performance liquid chromatography (HPLC) requires the use of small and uniform particles in order to achieve good column packing. The well‐known MOF material [Cu3(BTC)2] is, however, typically synthesized as a polydisperse mixture due to its nucleation and growth mechanism. It is demonstrated how a new synthesis method for [Cu3(BTC)2] enables the formation of the MOF inside the pores of silica beads often used in chromatography, leading to monodisperse silica–MOF composite spheres with a uniform particle size of 3 μm. When employed as an HPLC stationary phase, this material combines the good column packing properties of the silica and separation ability of the MOF material.
Nanoscale Metal–Organic Frameworks: Magnetic Resonance Imaging Contrast Agents and Beyond
Authors: Della Rocca Joseph , Lin Wenbin 
Published: July 2010

AbstractMagnetic resonance imaging (MRI) is an imaging technique based on the detection of nuclear spin reorientations in a magnetic field. MRI provides high spatial resolution and soft‐tissue contrast in anatomical images, and a large penetration depth; however, it is relatively insensitive and typically relies on large doses of administered contrast agents to give adequate contrast between normal and diseased tissues. This review covers the development of nanoscale metal–organic frameworks (NMOFs) as novel MRI contrast agents. NMOFs not only provide an effective vehicle for delivering large amounts of paramagnetic metal centers but also exhibit enhanced per‐metal‐based relaxivity relative to clinically used small‐molecule contrast agents. The in vitro and in vivo effectiveness of these agents has also been demonstrated. The potential of NMOFs as contrast agents for other imaging modalities, such as optical imaging (OI) and X‐ray computed tomography (CT), and as chemical and biological sensors is also discussed.
Dihydrogen Bonding, Proton Transfer and Beyond: What We Can Learn from Kinetics and Thermodynamics
Authors: Belkova Natalia V. , Epstein Lina M. , Shubina Elena S. 
Published: July 2010

AbstractHydrogen bonding to transition metal hydride complexes and its role in the proton transfer process has been a subject of the authors' research interest in recent years. The present microreview analyzes the relationships of kinetic and thermodynamic parameters of dihydrogen bonding, MH···HA, proton transfer, yielding [M(η2‐H2)] species, and subsequent steps such as [M(η2‐H2)] to [M(H)2] isomerization or H2 evolution on the basis of all data acquired so far. It aims at showing the factors that determine the stability of the species involved, the physico‐chemical (thermodynamic and kinetic) origin of the effects observed, and, ideally, allow one to better govern the hydrides reactivity.
The Last of the Five: the Elusive “Tantalum(III) Bromide”, a Perovskite‐Related Salt, [{Ta6}Br12]Br3[TaBr6]0.86
Authors: Habermehl Katja , Mudring Anja‐Verena , Meyer Gerd 
Published: July 2010

AbstractThe system Ta/Br contains, according to a phase diagram determination of 1965, five compounds. The crystal structures of TaBr5, TaBr4 as well as of Ta6Br15 and Ta6Br14 are known. The elusive “TaBr3” was now obtained as single crystals from the reduction of TaBr5 at the wall of the tantalum reaction container in the presence of a NaBr or RbBr flux. Its structure is that of a stuffed derivative of the structure of Ta6Br15. As this is related to the ReO3‐type of structure, “TaBr3” is related to the perovskite‐type of structure, in accord with the formulation [{Ta6}Br12]Br3[TaBr6]0.862(13) = [Ti]O3[Ca], with an under‐occupation of the cuboctahedral site. With the composition TaBr2.94 it represents the lower end of a homogeneity range TaBr3–x once reported.
AuI‐Catalyzed Direct Hydroamination/Hydroarylation and Double Hydroamination of Terminal Alkynes
Authors: Patil Nitin T. , Lakshmi Pediredla G. V. V. , Singh Vipender 
Published: July 2010

AbstractAn efficient method for formal Markownikoff hydroamination/hydroarylation and double hydroamination of terminal alkynes has been developed. For example, treatment of terminal alkynes with amino‐aromatics or diamines in the presence of 2–5 mol‐% of Ph3PAuNTf2 in toluene at 100 °C gave the corresponding products in excellent yields. The method was shown to be applicable to a broad range of substrates and, more importantly, unlike our previously reported method, a tethered hydroxy group in the alkyne is not necessary. The mechanism of the reaction is also discussed.
Optically Active N‐ and C‐Terminal Building Blocks for the Synthesis of Peptidyl Olefin Peptidomimetics
Authors: Mirilashvili Sima , Chasid‐Rubinstein Naama , Albeck Amnon 
Published: July 2010

AbstractPeptidyl olefin peptidomimetics serve as biologically active compounds or as intermediates for other peptidyl isosteres. The N‐terminal side of the C=C bond could be easily prepared in an optically pure form from α‐amino acids. Synthesis of C‐terminal building blocks in an optically pure form is more challenging. We developed a chemoenzymatic stereoselective approach to such optically active C‐terminal building blocks to be assembled into peptidyl olefins by a variety of reactions. They include an electrophilic aldehyde and nucleophilic sulfone, phosphonium salt, phosphonate, and diselenide. Key enzymatic hydrolysis of prochiral diesters to the corresponding hydroxy esters introduces optical activity. The sequence of the subsequent chemical reactions, either protection–hydrolysis–functionalization or functionalization–hydrolysis–protection, determines the absolute stereochemistry of the final building blocks.
Convergent Synthesis and Biological Evaluation of Syringolin A and Derivatives as Eukaryotic 20S Proteasome Inhibitors (Eur. J. Org. Chem. 21/2010)
Authors: Clerc Jérôme , Schellenberg Barbara , Groll Michael , Bachmann André S. , Huber Robert , Dudler Robert , Kaiser Markus 
Published: July 2010

AbstractThe cover picture shows the key steps of a convergent and versatile synthesis of Syringolin A (SylA) and other syrbactins. SylA is a small‐molecule virulence factor produced by some plant pathogenic Pseudomonas syringae pv. syringae strains during infection. It leads to irreversible inhibition of the plant's 20S proteasome (lower right corner depicts the binding mode of SylA to one of the active‐site centres of the proteasome), resulting in the so‐called brown‐spot disease. The synthetic preparation of SylA and its analogues opens up further possibilities for biological investigation into the mode of action of SylA in plant–pathogen interactions. Details are discussed in the article by M. Kaiser et al. on p. 3991 ff.
Study of Electrochemical Processes with Coupled Homogeneous Chemical Reaction in Differential Pulse Voltammetry at Spherical Electrodes and Microhemispheres
Authors: Laborda Eduardo , Martínez‐Ortiz Francisco , Molina Ángela 
Published: July 2010

AbstractHomogeneous chemical reactions coupled to oxidation‐reduction processes at electrode surfaces are very common in electrochemistry. In this paper we cope with the application of Differential Pulse Voltammetry at spherical electrodes and microhemispheres for the study of this kind of systems. Analytical expressions are deduced from which the influence of the different experimental variables is examined. Several diagnostic criteria for elucidation of the reaction mechanism from DPV peak parameters are given, as well as working curves for extraction of the kinetic rate constants of the chemical reaction.
Nanobiocomposite Modified Carbon‐Ceramic Electrode Based on Nano‐TiO2‐Plant Tissue and Its Application for Electrocatalytic Oxidation of Dopamine
Authors: Majidi Mir Reza , Asadpour‐Zeynali Karim , Gholizadeh Sima 
Published: July 2010

AbstractA new modified carbon‐ceramic electrode was prepared by incorporating TiO2 nanoparticle into sol‐gel network by accompanying apple tissue. A mixture of fine graphite powder with 15 wt% of TiO2 nanoparticle was used for the preparation of the carbon matrix and finally modification with a known amount weighted of apple tissue. The apple tissue containing polyphenol oxidase enzyme acts as molecular recognition element. The electrocatalytic oxidation of dopamine was investigated on the surface of the nanobiocomposite modified carbon‐ceramic electrode using cyclic voltammetry, chronoamperometry and amperometry techniques. Effect of pH, scan rate, TiO2 percentage on the response of modified electrode was studied. The prepared modified electrode presented a linear range for dopamine from 5.0×10−6 to 1.2×10−3 M in buffered solutions with pH 7.4 by amperometry. The detection limit was 3.41×10−6 M dopamine. The response of the modified carbon‐ceramic electrode and unmodified carbon‐ceramic electrode was compared.
A Study of the Modification of the Gold Electrode Surface with a Calix[4]arene Self‐Assembled Monolayer
Authors: Šustrová Barbora , Štulík Karel , Mareček Vladimír , Janda Pavel 
Published: July 2010

AbstractSubstituted calix[4]arene molecules were used to modify the gold disk electrode surface and the electrochemical properties of this electrode were compared with those of the bare electrode. Cyclic voltammetry measurements permitted the calculation of a Langmuir‐type adsorption isotherm for the formation of the calixarene SAM. The calixarene adsorption from chloroform solution appeared to be more effective, compared to the adsorption from DMF solution, but the process was less reproducible. Preliminary results, obtained by the atomic force microscopy measurements, indicate that the calixarene molecules form a stable monolayer on the Au(111) surface and the SAM structure depends on the solvent used. Impedance measurements demonstrate that the capacity of the modified electrode varies in the presence of ions, depending on their size and shape; this can potentially be utilized in designing ion‐selective sensors.
Adsorption of Methonine at Mercury/Aqueous Solution of Chlorate(VII) Interface; Dependence on the Supporting Electrolyte Concentration
Authors: Nosal‐Wiercińska Agnieszka , Dalmata Grażyna 
Published: July 2010

AbstractAdsorption of methionine on the mercury electrode from 0.5 to 8 mol dm−3 chlorates(VII) was examined. In all the systems studied the relative surface excesses of methionine increase with the increase of electrode charge and adsorbate concentration, they depend also on chlorates(VII) concentration. The adsorption parameters were determined from the Frumkin and virial isotherms. It was stated that the adsorption parameters change together with the change of supporting electrolyte concentration, what points at competitive adsorption of methionine and ClO$\rm{{_{4}^{-}}}$ ions and electrostatic interactions between the water dipoles and methionine in the double layer.
High‐Sensitivity Determination of Lead(II) and Cadmium(II) Based on the CNTs‐PSS/Bi Composite Film Electrode
Authors: Jia Xiaofang , Li Jing , Wang Erkang 
Published: July 2010

AbstractA high‐sensitivity sensing platform for lead(II) and cadmium(II) based on the bismuth modified carbon nanotubes (CNTs)‐poly(sodium 4‐styrenesulfonate) composite film electrode (CNTs‐PSS/Bi) was fabricated. The composite film CNTs‐PSS/Bi provided remarkably improved sensitivity and reproducibility compared with previously reported CNTs‐modified electrodes. The detection limits were estimated to be 0.04 ppb for lead(II) and 0.02 ppb for cadmium(II) with a preconcentration time of 120 s, respectively. The linear responses of Cd2+ and Pb2+ were over the ranges of 0.5–50 ppb and 0.5–90 ppb, respectively. Finally, the practical application of the proposed method was verified in the real water sample with satisfactory results.
Kinetic and thermodynamic studies of the biosorption of Cu(II) by Agaricus campestris
Authors: Danış Ümmühan 
Published: July 2010

AbstractAgaricus campestris was used as an adsorbent for the adsorption of Cu(II) ions in water. The adsorption process was carried out in a batch process and the effects of contact time, initial pH, initial Cu(II) ion concentration, adsorbent amount, and temperature on the adsorption were investigated. Kinetic calculation results from the recent experiments showed that the amount of adsorbed Cu(II) increased with increasing Cu(II) concentration, pH, temperature, contact time and with decreasing adsorbent amount. Pseudo‐second‐order reaction model provided the best description of the data with a correlation coefficient 0.99–1 for different initial metal concentrations and temperatures were studied. The equilibrium data were well fitted to the Langmuir isotherm. The maximum adsorption capacity for Cu(II) was 32.52 mg g−1 at 298 K. Thermodynamic parameters such as ΔH
0, ΔS
0 and ΔG0 were calculated. The adsorption process was found to be endothermic and spontaneous. © 2010 American Institute of Chemical Engineers Environ Prog, 2011
Effects of boron pollution in the lower buyuk menderes basin (Turkey) on agricultural areas and crops
Authors: Koç Cengiz 
Published: July 2010

AbstractThe aim of this study is to study the effects of Boron (B) pollution in Buyuk Menderes river on planted crops and agricultural areas constructed in the irrigation schemes by the State Hydraulic Works (DSI) of the Lower Buyuk Menderes basin, Turkey. The studied irrigation schemes in the basin are Saraykoy, Pamukkale, Nazilli, Aydin, Sultanhisar, Koçarli, and Soke. Mean B concentrations of river water used in the irrigation schemes ranged from 0.10 to 0.43 mgB L−1 for the period of 2008 to 2009. A total of 100,556 ha of the agricultural area and the basin groundwater resources are under the influence of B pollution from the Buyuk Menderes river. The amount of B accumulating in soils and seepage in the groundwater due to the used irrigation water was 18,495,350 and 9153 kgB yr−1, respectively. B accumulating in the irrigated area ranged from 670 to 4521 gB ha−1 yr−1. In total, 19,410,650 kg yr−1 of B have negatively affected the agricultural areas, groundwater resources, and environmental conditions. Nazilli and Sultanhisar irrigation areas are under the threat of wastewater discharges originating from the Kizildere geothermal power plant and Tekke thermal spring. Particularly, fruit crops such as citrus, peach, plum, fig, olive, and wheat, strawberry, sunflower are to be negatively affected by the present B concentrations in the irrigation water. © 2010 American Institute of Chemical Engineers Environ Prog, 2011
Remote sensing analysis of physical complexity of North Pacific Rim rivers to assist wild salmon conservation
Authors: Luck Matthew , Maumenee Niels , Whited Diane , Lucotch John , Chilcote Samantha , Lorang Mark , Goodman Daniel , McDonald Kyle , Kimball John , Stanford Jack 
Published: July 2010

AbstractSalmon populations are highly variable in both space and time. Accurate forecasting of the productivity of salmon stocks makes effective management and conservation of the resource extremely challenging. Furthermore, widespread and consistent data on the productivity of species‐specific and total salmon stocks in a river are almost nonexistent. Ranking rivers based on physical complexity derived from remote sensing allows rivers to be objectively compared. Our approach considered rivers with great geomorphic complexity (e.g. having expansive, multichanneled floodplains and/or on‐channel lakes) as likely to have greater productivity of salmon than rivers flowing in constrained or canyon‐bound channels. Our objective was to develop a database of landscape metrics that could be used to rank the rivers in relation to potential salmon productivity. We then examined the rankings in relation to existing empirical (monitoring) data describing productivity of salmon stocks. To extract the metrics for each river basin we used a digital elevation model and multispectral satellite imagery. We developed procedures to extract channel networks, floodplains, on‐channel lakes and other catchment features; variables such as catchment area, channel elevation, main channel length, floodplain area, and density of hydrojunctions (nodes) were measured. We processed 1509 catchments in the North Pacific Rim including the Kamchatka Peninsula in Russia and western North America. Overall, catchments were most physically complex in western Kamchatka and western Alaska, and particularly on the Arctic North Slope of Alaska. We could not directly examine coherence between potential and measured productivity except for a few rivers, but the expected relationship generally held. The resulting database and systematic ranking are objective tools that can be used to address questions about landscape structure and biological productivity at regional to continental extents, and provide a way to begin to efficiently prioritize the allocation of funding and resources towards salmon management and conservation. Copyright © 2010 John Wiley & Sons, Ltd.
Development of an automated method for continuous detection and quantification of cliff erosion events
Authors: Bernatchez Pascal , Jolivet Yvon , Corriveau Maude 
Published: July 2010

AbstractThree intrusive systems of detection and quantification of coastal erosion events (using thermocouples and thermal pins) were developed and tested from 2005 to 2008 in different regions of the Gulf and maritime estuary of the St Lawrence (Quebec, Canada). The 3‐m‐long thermal pins inserted inside unconsolidated deposits allow the monitoring of erosion for a time period sometimes extending over several seasons. The thermocouple or thermocable method allows not only the instrumentation of unconsolidated deposits but also of rocky and cohesive substrate to a depth of 85 cm. An autonomous microclimatic station located near the experimental sites simultaneously samples temperature parameters, precipitation, snow cover, wind speed and direction as well as global radiation.The differential analysis of cliff thermal regime performed simultaneously with an analysis of air temperature makes it possible to determine the activation periods of coastal erosion processes. The results also make it possible to establish with precision the actual influence of rapid variations of certain climatic and microclimatic parameters (radiation, presence of snow cover, precipitation, etc.) on the physical state of surfaces and also on the activation of certain physical processes connected to coastal erosion events. The automated thermal erosion pin system (ATEPS) allows high temporal resolution (i.e. continuous) monitoring, enabling a real coupling of coastal erosion rates and climatic parameters. Preliminary results with the ATEPS system indicate that mild winter temperature and direct solar radiation are significant factors controlling cliff retreat rates. Moreover, the melting of segregation ice during the spring thaw contributed for more than 70% of cliff retreat against only 30% for frost shattering. Copyright © 2010 John Wiley & Sons, Ltd.
Instability of coral limestone cliffs due to extreme waves
Authors: Kogure Tetsuya , Matsukura Yukinori 
Published: July 2010

AbstractMany boulders are located around the coastal cliffs with height of below 5 m made of coral limestone at Kuro‐shima, Okinawa, Japan. The origin of the boulders appears to be coral limestone cliffs which show developed notches. We undertook stability analysis, involving the wave pressure due to tsunamis, of wave‐induced collapse of the cliffs. We find that extreme waves are capable of inducing cliff collapse, as observed in circumstances where gravity is insufficient. Copyright © 2010 John Wiley and Sons, Ltd.