bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled versus uncoupled hindcast simulations of the Madden‐Julian Oscillation in the Year of Tropical Convection
Authors: Shelly Ann , Xavier Prince , Copsey Dan , Johns Tim , Rodríguez José M. , Milton Sean , Klingaman Nicholas 
Published: July 2014

AbstractThis study investigates the impact of a full interactive ocean on daily initialized 15 day hindcasts of the Madden‐Julian Oscillation (MJO), measured against a Met Office Unified Model atmosphere control simulation (atmospheric general circulation model (AGCM)) during a 3 month period of the Year of Tropical Convection. Results indicate that the coupled configuration (coupled general circulation model (CGCM)) extends MJO predictability over that of the AGCM, by up to 3–5 days. Propagation is improved in the CGCM, which we partly attribute to a more realistic phase relationship between sea surface temperature (SST) and convection. In addition, the CGCM demonstrates skill in representing downwelling oceanic Kelvin and Rossby waves which warm SSTs along their trajectory, with the potential to feedback on the atmosphere. These results imply that an ocean model capable of simulating internal ocean waves may be required to capture the full effect of air‐sea coupling for the MJO.
Correlation of cycles in Lava Lake motion and degassing at Erebus Volcano, Antarctica
Authors: Peters Nial , Oppenheimer Clive , Killingsworth Drea Rae , Frechette Jed , Kyle Philip 
Published: July 2014

AbstractSeveral studies at Erebus volcano have recorded pulsatory behavior in many of the observable properties of its active lava lake. A strong correlation between the variations in surface speed of the lake and the composition of gas emitted has previously been noted. While previous studies have shown that the SO2 flux and the surface elevation exhibit pulsatory behavior with a similar period to that of the surface speed and gas composition, suggesting they are linked, a lack of overlap between the different measurements has prevented direct comparisons from being made. Using high time‐resolution measurements of surface elevation, surface speed, gas composition, and SO2 flux, we demonstrate for the first time an unambiguous link between the cyclic behavior in each of these properties. We also show that the variation in gas composition may be explained by a subtle change in oxygen fugacity. The cycles are found to be in‐phase with each other, with a small but consistent lag of 1–3 min between the peaks in surface elevation and surface speed. Explosive events are found to have no observable effect on the pulsatory behavior beyond the ∼5 min period required for lake refill. The close correspondences between the varying lake surface motion, gas flux and composition, and modeled oxygen fugacity suggest strong links between magma degassing, redox change, and the fluid dynamics of the shallow magmatic system.
Evaluation of in situ stress changes with gas depletion of coalbed methane reservoirs
Authors: Liu Shimin , Harpalani Satya 
Published: July 2014

AbstractA sound knowledge of the stress path for coalbed methane (CBM) reservoirs is critical for a variety of applications, including dynamic formation stability evaluation, long‐term gas production management, and carbon sequestration in coals. Although this problem has been extensively studied for traditional oil and gas reservoirs, it is somewhat unclear for CBM reservoirs. The difference between the stress paths followed in the two reservoir types is expected to be significant given the unique sorption‐induced deformation phenomenon associated with gas production from coal. This results in an additional reservoir volumetric strain, which induces a rather “abnormal” loss of horizontal stress with depletion, leading to continuous changes in the subsurface formation stresses, both effective as well as total. It is suspected that stress changes within the reservoir triggers formation failure after significant depletion. This paper describes an experimental study, carried out to measure the horizontal stress under in situ depletion conditions. The results show that the horizontal stress decreases linearly with depletion under in situ conditions. The dynamic stress evolution is theoretically analyzed, based on modified poroelasticity associated with sorption‐induced strain effect. Additionally, the failure tendency of the reservoir under in situ conditions is analyzed using the traditional Mohr‐Coulomb failure criterion. The results indicate that depletion may lead to coal failure, particularly in deeper coalbeds and ones exhibiting large matrix shrinkage.
Decadal trends in global pelagic ocean chlorophyll: A new assessment integrating multiple satellites, in situ data, and models
Authors: Gregg Watson W. , Rousseaux Cécile S. 
Published: July 2014

AbstractQuantifying change in ocean biology using satellites is a major scientific objective. We document trends globally for the period 1998–2012 by integrating three diverse methodologies: ocean color data from multiple satellites, bias correction methods based on in situ data, and data assimilation to provide a consistent and complete global representation free of sampling biases. The results indicated no significant trend in global pelagic ocean chlorophyll over the 15 year data record. These results were consistent with previous findings that were based on the first 6 years and first 10 years of the SeaWiFS mission. However, all of the Northern Hemisphere basins (north of 10° latitude), as well as the Equatorial Indian basin, exhibited significant declines in chlorophyll. Trend maps showed the local trends and their change in percent per year. These trend maps were compared with several other previous efforts using only a single sensor (SeaWiFS) and more limited time series, showing remarkable consistency. These results suggested the present effort provides a path forward to quantifying global ocean trends using multiple satellite missions, which is essential if we are to understand the state, variability, and possible changes in the global oceans over longer time scales.
A semianalytical solution for the Boussinesq equation with nonhomogeneous constant boundary conditions
Authors: Dias Nelson L. , Chor Tomás L. , de Zárate Ailín Ruiz 
Published: July 2014

AbstractThe Boussinesq groundwater equation is widely used in hydrology to predict streamflow from an unconfined aquifer and derive the aquifer's saturated hydraulic conductivity and drainable porosity, and to predict water table height in drainage engineering. In this work, we solve this equation in an unconfined horizontal aquifer for nonhomogeneous boundary conditions for the water table height. The solution is found in the form of a Taylor series that has a finite radius of convergence, which is different for each initial condition. We also present an expression for the flux boundary condition at the origin as a function of the depth of the adjoining stream that automatically satisfies the boundary condition at infinity, and thus eliminates the need for a trial‐and‐error approach for the solution, which is accurate to 10−7. In order to obtain an approximation for the water table height in the region where the series solution diverges, first we computed a diagonal Padé approximation from the series coefficients, which converges in a larger interval than the series, and then we matched it with a new asymptotic approximation for large values of the independent variable. We found that the proposed matched solution is better suited to cases where the water head at the origin is close to the initial water head in the aquifer.
Peptide‐Templated Acyl Transfer: A Chemical Method for the Labeling of Membrane Proteins on Live Cells
Authors: Reinhardt Ulrike , Lotze Jonathan , Zernia Sarah , Mörl Karin , Beck‐Sickinger Annette G. , Seitz Oliver 
Published: July 2014

AbstractThe development of a method is described for the chemical labeling of proteins which occurs with high target specificity, proceeds within seconds to minutes, and offers a free choice of the reporter group. The method relies upon the use of peptide templates, which align a thioester and an N‐terminal cysteinyl residue such that an acyl transfer reaction is facilitated at nanomolar concentrations. The protein of interest is N‐terminally tagged with a 22 aa long Cys‐E3 peptide (acceptor), which is capable of forming a coiled‐coil with a reporter‐armed K3 peptide (donor). This triggers the transfer of the reporter to the acceptor on the target protein. Because ligation of the two interacting peptides is avoided, the mass increase at the protein of interest is minimal. The method is exemplified by the rapid fluorescent labeling and fluorescence microscopic imaging of the human Y2 receptor on living cells.
Reprogramming Nonribosomal Peptide Synthetases for “Clickable” Amino Acids
Authors: Kries Hajo , Wachtel Rudolf , Pabst Anja , Wanner Benedikt , Niquille David , Hilvert Donald 
Published: July 2014

AbstractNonribosomal peptide synthetases (NRPSs) are multifunctional enzymes that produce a wide array of bioactive peptides. Here we show that a single tryptophan‐to‐serine mutation in phenylalanine‐specific NRPS adenylation domains enables the efficient activation of non‐natural aromatic amino acids functionalized with azide and alkyne groups. The resulting 105‐fold switch in substrate specificity was achieved without appreciable loss of catalytic efficiency. Moreover, the effective communication of the modified A domains with downstream modules in dipeptide synthetases permitted incorporation of O‐propargyl‐L‐tyrosine into diketopiperazines both in vitro and in vivo, even in the presence of competing phenylalanine. Because azides and alkynes readily undergo bioorthogonal click reactions, reprogramming NRPSs to accept non‐natural amino acids that contain these groups provides a potentially powerful means of isolating, labeling, and modifying biologically active peptides.
Polymerized high internal phase emulsion monoliths for the chromatographic separation of engineered nanoparticles
Authors: Hughes Jonathan M. , Budd Peter M. , Tiede Karen , Lewis John 
Published: July 2014

ABSTRACTPolyHIPEs of ethylene glycol dimethacrylate (EGDMA) and styrene/divinylbenzene were prepared by polymerization of water‐in‐oil high internal phase emulsions (HIPEs) within high pressure liquid chromatography (HPLC) columns. The columns were incorporated into a HPLC system affixed to an inductively‐coupled plasma mass spectrometer, and their potential for the separation of engineered nanoparticles was investigated. Triplicate injections of 5 and 10 nm gold particles injected onto a poly(styrene‐co‐divinylbenzene) polyHIPE column produced an average difference in retention time of 135 s. On a poly(EGDMA) column, triplicate injections of dysprosium containing polystyrene particles of 52 and 155 nm produced a difference in retention time of 8 s. In both cases the smaller particles eluted from the column first. Comparison, using scanning electron microscopy, of the polyHIPE columns after the separations, against freestanding monoliths produced from the same HIPEs, revealed no apparent change in the internal porous structure of the polyHIPEs. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 132, 41229.
Preparation of electrospun silk fibroin nanofibers from solutions containing native silk fibrils
Authors: Liu Zhi , Zhang Feng , Ming Jinfa , Bie Shiyu , Li Junjuan , Zuo Baoqi 
Published: July 2014

ABSTRACTElectrospinning solutions containing native silk fibrils with varied diameter and length were firstly achieved by dissolving silk in CaCl2/Formic acid solvents. The structure of nanofibrils significantly improved the spinnability of electrospinning solution. The diameter of electrospun silk fibroin (SF) nanofibers increased from 40 nm to 1.8 μm, which could be achieved through increasing the solution concentration from 2 to 10%, implying a good size control over a wide range in this process. The structure of SF nanofibers transferred from random coil to beta‐sheet, before and after ethanol treatment, respectively. The mechanical properties of the SF nanofibers were improved significantly with stress and strain at break of 11.15 MPa and 7.66% in dry state, and 3.32 MPa and 174.0% in wet state. The strategy for preparing SF nanofibers with improved mechanical properties and fiber diameter control over a wide range provides benefits for the application of this material. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41236.
Poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium): Synthesis, characterization, and its potential application for the removal of metal ions from aqueous solution
Authors: Valle Hernán , Sánchez Julio , Rivas Bernabé L. 
Published: July 2014

ABSTRACTIn the current study, poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium), poly(VP‐co‐AMPS), was prepared and used for the removal of Cu2+, Cd2+, and Ni2+ ions via a polymer‐enhanced ultrafiltration (PEUF) technique. The copolymer was synthesized by radical polymerization in an aqueous medium with a comonomer feed composition of 50:50 mol %. The molecular structure of the copolymer was elucidated by ATR‐FTIR and 1H NMR spectroscopy, and the average molecular weight was obtained by GPC. The copolymer composition was determined to be 0.42 for VP and 0.58 for AMPS by 1H NMR spectroscopy. The copolymer and homopolymers exhibited different retention properties for the metal ions. PAMPS exhibited a high retention capacity for all of the metal ions at both pH values studied. PVP exhibited selectivity for nickel ions. Poly(VP‐co‐AMPS) exhibited a lower retention capacity compared to PAMPS. However, for poly(VP‐co‐AMPS), selectivity for nickel ions was observed, and the retention of copper and cadmium ions increased compared to PVP. The homopolymer mixture containing PAMPS and PVP was inefficient for the retention of the studied metal ions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41272.
Robust Dynamic Output Feedback Guaranteed Cost Control for Discrete‐Time Systems with Time‐Varying Delays
Authors: Gyurkovics Éva , Takács Tibor 
Published: July 2014

ABSTRACTThe paper proposes a dynamic output feedback guaranteed cost control for uncertain discrete‐time delay systems, where the unknown nonlinearities/uncertainties of the system are permitted to take their values in a fairly general set. The delays are considered to be unknown time varying functions with known bounds. A sufficient condition for the existence of the guaranteed cost control is given by matrix inequalities. It is shown how these inequalities can be traced back to linear matrix inequalities. An iterative algorithm is proposed to improve the quality of the control by minimizing the upper bound of the cost function. Numerical examples illustrate the effectiveness of the proposed method.
Effect of liquid hot water pretreatment severity on properties of hardwood lignin and enzymatic hydrolysis of cellulose
Authors: Ko Ja Kyong , Kim Youngmi , Ximenes Eduardo , Ladisch Michael R. 
Published: July 2014

ABSTRACTLignin, one of the major components of lignocellulosic biomass, plays an inhibitory role on the enzymatic hydrolysis of cellulose. This work examines the role of lignin in pretreated hardwood, where extents of cellulose hydrolysis decrease, rather than increase with increasing severity of liquid hot water pretreatment. Hardwood pretreated with liquid hot water at severities ranging from log Ro = 8.25 to 12.51 resulted in 80–90% recovery of the initial lignin in the residual solids. The ratio of acid insoluble lignin (AIL) to acid soluble lignin (ASL) increased and the formation of spherical lignin droplets on the cell wall surface was observed as previously reported in the literature. When lignins were isolated from hardwoods pretreated at increasing severities and characterized based on glass transition temperature (Tg), the Tg of isolated lignins was found to increase from 171 to 180°C as the severity increased from log Ro = 10.44 to 12.51. The increase in Tg suggested that the condensation reactions of lignin molecules occurred during pretreatment and altered the lignin structure. The contribution of the changes in lignin properties to enzymatic hydrolysis were examined by carrying out Avicel hydrolysis in the presence of isolated lignins. Lignins derived from more severely pretreated hardwoods had higher Tg values and showed more pronounced inhibition of enzymatic hydrolysis. Biotechnol. Bioeng. 2015;112: 252–262. © 2014 Wiley Periodicals, Inc.
Non‐destructive label‐free continuous monitoring of in vitro chondrogenesis via electrical conductivity and its anisotropy
Authors: Oh Tong In , Kim Changhwan , Karki Bishal , Son Youngsook , Lee EunAh , Woo Eung Je 
Published: July 2014

ABSTRACTNon‐destructive label‐free continuous monitoring of in vitro tissue culture is an unmet demand in tissue engineering. Noting that different compositions of cartilage lead to different electrical tissue properties, we propose a new method to measure the electrical conductivity and its anisotropy during in vitro chondrogenesis. We used a conductivity tensor probe with 17 electrodes and a bio‐impedance spectroscopy (BIS) device to measure the conductivity values and the anisotropy ratios at the bottom and top surfaces of the tissue samples during the culture period of 6 weeks. Clearly distinguishing glycosaminoglycans (GAGs), collagen, and also various mixtures of them, the measured conductivity value and the estimated tissue anisotropy provide diagnostic information of the depth‐dependent tissue structure and compositions. Continuously monitoring the individual tissue during the entire chondrogenesis process without any adverse effect, the proposed method may significantly increase the productivity of cartilage tissue engineering. Biotechnol. Bioeng. 2015;112: 422–427. © 2014 Wiley Periodicals, Inc.
An Operando FTIR Spectroscopic and Kinetic Study of Carbon Monoxide Pressure Influence on Rhodium‐Catalyzed Olefin Hydroformylation
Authors: Kubis Christoph , Sawall Mathias , Block Axel , Neymeyr Klaus , Ludwig Ralf , Börner Armin , Selent Detlef 
Published: July 2014

AbstractThe influence of carbon monoxide concentration on the kinetics of the hydroformylation of 3,3‐dimethyl‐1‐butene with a phosphite‐modified rhodium catalyst has been studied for the pressure range p(CO)=0.20–3.83 MPa. Highly resolved time‐dependent concentration profiles of the organometallic intermediates were derived from IR spectroscopic data collected in situ for the entire olefin‐conversion range. The dynamics of the catalyst and organic components are described by enzyme‐type kinetics with competitive and uncompetitive inhibition reactions involving carbon monoxide taken into account. Saturation of the alkyl–rhodium intermediates with carbon monoxide as a cosubstrate occurs between 1.5 and 2 MPa of carbon monoxide pressure, which brings about a convergence of aldehyde regioselectivity. Hydrogenolysis of the acyl intermediate is fast at 30 °C and low pressure of p(CO)=0.2 MPa, but is of minus first order with respect to the solution concentration of carbon monoxide. Resting 18‐electron hydrido and acyl complexes that correspond to early and late rate‐determining states, respectively, coexist as long as the conversion of the substrate is not complete.
Complex‐Formation‐Enhanced Fluorescence Quenching Effect for Efficient Detection of Picric Acid
Authors: Ding Aixiang , Yang Longmei , Zhang Yuyang , Zhang Gaobin , Kong Lin , Zhang Xuanjun , Tian Yupeng , Tao Xutang , Yang Jiaxiang 
Published: July 2014

AbstractAmine‐functionalized α‐cyanostilbene derivatives (Z)‐2‐(4‐aminophenyl)‐3‐(4‐butoxyphenyl)acrylonitrile (ABA) and (Z)‐3‐(4‐butoxyphenyl)‐2‐[4‐(butylamino)phenyl]acrylonitrile (BBA) were designed for specific recognition of picric acid (PA), an environmental and biological pollutant. The 1:1 host–guest complexes formed between the chemosensors and PA enhanced fluorescence quenching, thus leading to sensitive and selective detection in aqueous media and the solid phase.
A Molecular Placeholder Strategy To Access a Family of Transition‐Metal‐Functionalized Vanadium Oxide Clusters
Authors: Kastner Katharina , Margraf Johannes T. , Clark Timothy , Streb Carsten 
Published: July 2014

AbstractSystematic access to metal‐functionalized polyoxometalates has thus far been limited to lacunary tungsten oxide and molybdenum oxide clusters. The first controlled, stepwise bottom‐up assembly route to metal‐functionalized molecular vanadium oxides is now presented. A di‐vacant vanadate cluster with two metal binding sites, (DMA)2[V12O32Cl]3− (DMA=dimethylammonium) is formed spontaneously in solution and characterized by single‐crystal X‐ray diffraction, ESI mass spectrometry, 51V NMR spectroscopy, and elemental analyses. In the cluster, the metal binding sites are selectively blocked by hydrogen‐bonded DMA placeholder cations. Reaction of the cluster with transition metals TM (Fe3+, Co2+, Cu2+, Zn2+) gives access to mono‐functionalized vanadate clusters (DMA)[{TM(L)}V12O32Cl]n− (L=ligand). Metal binding is accomplished by significant distortions of the vanadium oxide framework reminiscent of a pincer movement. Cluster stability under technologically relevant conditions in the solid‐state and solution is demonstrated.
Kinetic Resolution of Profens by EnantioselectiveEsterification Catalyzed by Candida antarctica and Candida rugosa Lipases
Authors: Sikora Adam , Siódmiak Tomasz , Marszałł Michał Piotr 
Published: July 2014

ABSTRACTProfens (2‐arylpropionic acids) are known as one of the major nonsteroidal antiinflammatory drugs (NSAIDs) used in the treatment of inflammation associated with tissue injury. The inflammatory activity of profens is mainly due to their (S)‐enantiomer, whereas they are commercially available not only as pure enantiomers, but as racemates as well. There are several methods widely used in order to obtain enantiomerically pure compounds, however, the kinetic resolution with the application of lipases as biocatalysts may have an added advantage in the production of optically pure active pharmaceutical ingredients, such as milder reaction conditions, reduced energy requirements, and production costs. The aim of this study was to compare the results described in the literature in the case of the influence of reaction medium, alcohol moiety, and reaction temperature on the catalytic activity of lipases from Candida antarctica and Candida rugosa. Chirality 26:663–669, 2014. © 2014 Wiley Periodicals, Inc.