bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mobile phase modifier effects in multimodal cation exchange chromatography
Authors: Holstein Melissa A. , Parimal Siddharth , McCallum Scott A. , Cramer Steven M. 
Published: August 2011

AbstractThis study examines protein adsorption behavior and the effects of mobile phase modifiers in multimodal chromatographic systems. Chromatography results with a diverse protein library indicate that multimodal and ion exchange resins have markedly different protein binding behavior and selectivity. NMR results corroborate the stronger binding observed for the multimodal system and provide insight into the structural basis for the observed binding behavior. Protein‐binding affinity and selectivity in multimodal and ion exchange systems are then examined using a variety of mobile phase modifiers. Arginine and guanidine are found to have dramatic effects on protein adsorption, yielding changes in selectivity in both chromatographic systems. While sodium caprylate leads to slightly weaker chromatographic retention for most proteins, certain proteins exhibit significant losses in retention in both systems. The presence of a competitive binding mechanism between the multimodal ligand and sodium caprylate for binding to ubiquitin is confirmed using STD NMR. Polyol mobile phase modifiers are shown to result in increased retention for weakly bound proteins and decreased retention for strongly bound proteins, indicating that the overall retention behavior is determined by a balance between changes in electrostatic and hydrophobic interactions. This work provides an improved understanding of protein adsorption and mobile phase modifier effects in multimodal chromatographic systems and sets the stage for future work to develop more selective protein separation systems. Biotechnol. Bioeng. 2012;109: 176–186. © 2011 Wiley Periodicals, Inc.
Hydrolysis of Plutonium(VI) at Variable Temperatures (283–343 K)
Authors: Rao Linfeng , Tian Guoxin , Di Bernardo Plinio , Zanonato PierLuigi 
Published: August 2011

AbstractThe hydrolysis of PuVI was studied at variable temperatures (283–343 K) by potentiometry, microcalorimetry, and spectrophotometry. Three hydrolysis reactions, mPuO22++nH2O=(PuO2)m(OH)n+nH+), in which (n,m)=(1,1), (2,2), and (5,3), were invoked to describe the potentiometric and calorimetric data. The equilibrium constants (*βn,m) were determined by potentiometry at 283, 298, 313, 328, and 343 K. As the temperature was increased from 283 to 343 K, *β1,1, *β2,2, and *β5,3, increased by 1, 1.5, and 4 orders of magnitude, respectively. The enhancement of hydrolysis at elevated temperatures is mainly due to the significant increase of the degree of ionization of water as the temperature increases. Measurements by microcalorimetry indicate that the three hydrolysis reactions are all endothermic at 298.15 K, with enthalpies of (35.0±3.4) kJ mol−1, (65.4±1.0) kJ mol−1, and (127.7±1.7) kJ mol−1 for ΔH1,1, ΔH2,2, and ΔH5,3, respectively. The hydrolysis constants at infinite dilution have been obtained with the Specific Ion Interaction approach. The applicability of three approaches for estimating the equilibrium constants at different temperatures, including the constant enthalpy approach, the DQUANT equation, and the Ryzhenko–Bryzgalin model, were evaluated with the data from this work.
Factors That Regulate the Conformation of m‐Benziporphodimethene Complexes: Agostic Metal–Arene Interaction, Hydrogen Bonding, and η2,π Coordination
Authors: Chang Gao‐Fong , Wang Chun‐Hung , Lu Hung‐Chieh , Kan Lou‐Sing , Chao Ito , Chen Wei Hao , Kumar Anil , Lo Liyang , dela Rosa Mira Anne C. , Hung Chen‐Hsiung 
Published: August 2011

AbstractGroup 12 and silver(I) tetramethyl‐m‐benziporphodimethene (TMBPDM) complexes with phenyl, methylbenzoate, or nitrophenyl groups as meso substituents were synthesized and fully characterized. The dimeric silver(I) complex displays an unusual η2,π coordination from the β‐pyrrolic CC bond to the silver ion. All of the complexes displayed a close contact between the metal ion and the inner C(22)H(22) on the m‐phenylene ring. The downfield chemical shifts of H(22) and large coupling constants between CdII and H(22) strongly support the presence of an agostic interaction between the metal ion and inner C(22)–H(22). Crystal structures revealed that the syn form is the predominant conformation for TMBPDM complexes. This is distinctively different from the exclusive anti conformation observed in m‐benziporphyrin and tetraphenyl‐m‐benziporphodimethene (TPBPDM) complexes. Evidently, intramolecular hydrogen‐bonding interactions between axial chloride and methyl groups stabilize syn conformations. Unlike the merely syn conformation observed in the solid‐state structures of TMBPDM complexes that contain an axial chloride, in solution these complexes display highly solvent‐ and temperature‐dependent syn/anti ratio changes. The observation of dynamic 1H NMR spectroscopic scrambling between syn and anti conformations from the titration of chloride ion into the solution of the TMBPDM complex suggests that axial ligand exchange is a likely pathway for the conversion between syn and anti forms. Theoretical calculations revealed that intermolecular hydrogen‐bonding interactions between the axial chloride and CHCl3 stabilizes the anti conformation, which explains the increased ratio for the anti form when dichloromethane or chloroform was used as the solvent.
Kinetic Resolution of α‐Substituted Alkanoic Acids Promoted by Homobenzotetramisole
Authors: Yang Xing , Birman Vladimir B. 
Published: August 2011

AbstractA new method for catalytic nonenzymatic kinetic resolution of α‐substituted alkanoic acids has been developed, which relies on their activation with DCC followed by enantioselective alcoholysis of the intermediate symm‐anhydrides in the presence of the amidine‐based catalyst homobenzotetramisole (HBTM). Moderate to excellent selectivity factors (s=5–96) have been obtained in the case of several classes of substrates, namely, α‐aryl‐, α‐aryloxy/alkoxy‐, α‐halo‐, α‐azido‐, and α‐phthalimido‐alkanoic acids. Under similar conditions, α‐(arylthio/alkylthio)‐alkanoic acids undergo dynamic kinetic resolution providing corresponding esters in up to 92 % ee and up to 93 % yield.
Material Flows as a Basis for an Innovative Control Concept for Municipal Solid Waste Incinerators
Authors: Richers Ulf 
Published: August 2011

AbstractDurch die Gewinnung von Sekundärbrennstoffen für den Einsatz bei energieintensiven Prozessen entstehen Abfallfraktionen mit höheren Chlorgehalten. Die Entsorgung dieser Fraktionen in Abfallverbrennungsanlagen ist problematisch, denn Chlor ist maßgeblich an Korrosionsprozessen beteiligt. Zur Minderung der Korrosionsprozesse wird, ausgehend von der Stoffbilanz für Chlor in einer Abfallverbrennungsanlage, ein neues Verfahren zur besseren Regelung von Abfallverbrennungsanlagen vorgestellt. Im Mittelpunkt steht eine separate geregelte Zuführung von Abfällen mit höheren Chlorkonzentrationen.
Safety Investigations for Operation of Microreactors Inside the Explosion Region
Authors: Hieronymus Hartmut , Fischer Johannes , Heinrich Sebastian , Liebner Christian , Lange Thomas , Klemm Elias 
Published: August 2011

AbstractEs wird eine Methode zur sicherheitstechnischen Untersuchung von Mikroreaktoren und mikrostrukturierten Komponenten, die im Explosionsbereich betrieben werden sollen, vorgestellt. Mikrostrukturierte Reaktoren sind nicht inhärent sicher, wenngleich der Bereich der sicheren Betriebsbedingungen gegenüber konventionellen Reaktoren erweitert ist. Der Explosionsbereich kann durch die Mikrostrukturen eingeengt werden. Am Beispiel von Ethylen/Sauerstoff‐Gemischen und Ethylen/N2O‐Gemischen wird hinsichtlich der Ausbreitung von Detonationen durch Kapillarrohre gezeigt, dass die sogenannte λ/3‐Regel angewandt werden kann. Darüber hinaus werden erste Ergebnisse der Untersuchung der Ausbreitung von Explosionen durch einen Mikroreaktor mit rechteckigem Strömungskanal vorgestellt.
Predicting group partitions in mobile ad hoc networks
Authors: Zhang Yan , Low Chor Ping , Ng Jim Mee , Wang Ting 
Published: August 2011

SUMMARYGroup mobility is prevalent in many mobile ad hoc network applications such as disaster recovery, military actions, etc., and group partitions are unavoidable in such kinds of dynamic networks. Group partition may occur when mobile nodes move in diverse mobility patterns and causes the network to be partitioned into disconnected components. It may result in severe link disconnections, which then interrupt intergroup communications. By examining the group mobility pattern, we can predict the possibility of network partitions, and thus minimize the amount of communication disruptions. In this paper, we introduce a system for predicting potential group partitions in mobile ad hoc networks. On the basis of historical group mobility information, a quadratic regression model is formulated to predict the direction and speed of a group's movement. A group's micromovement is ignored and is replaced by significant linear displacement to measure its mobility to improve the prediction accuracy. We also discuss the notion of safe distance between adjacent groups, based on which the time duration before the occurrence of group partitioning can be measured. Experimental results show that our proposed prediction method demonstrates its effectiveness and efficiency in group partition predictions such that remedial actions can be taken in advance to avoid network disconnection. Copyright © 2011 John Wiley & Sons, Ltd.
Should We Care About the Needs of Non‐humans? Needs Assessment: A Tool for Environmental Conflict Resolution and Sustainable Organization of Living Beings
Authors: Jolibert Catherine , Max‐Neef Manfred , Rauschmayer Felix , Paavola Jouni 
Published: August 2011

ABSTRACTThis article extends the Human‐scale Development methodology to include non‐humans. We found this wider approach to be helpful in analysing the conflict of interest between fish farming and otter protection in the Natural Reserve of the Sado River estuary in Portugal. Our analysis of this environmental conflict goes beyond the anthropocentric view restricted to human needs to include all stakeholder needs, i.e. both human and non‐human ‘actants’. The needs‐based analysis aims to ensure that local development strategies are more sustainable, improving interactions between all living beings, not just humans. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
Statins inhibit iNOS‐mediated microbicidal potential of activated monocyte‐derived dendritic cells by an IFN‐β‐dependent mechanism
Authors: Domínguez Pilar M. , López‐Bravo María , Kalinke Ulrich , Ardavín Carlos 
Published: August 2011

AbstractStatins are prescribed to 25 million people worldwide for treating hypercholesterolemia and reducing the risk of cardiovascular diseases. However, the side effects of statins on immunity, and particularly on DC immunobiology, have not been analyzed in‐depth. Here, we have investigated the impact of lovastatin treatment during monocyte differentiation into DCs on the responsiveness of the resulting monocyte‐derived DCs (moDCs) to TLR‐mediated activation. Lovastatin positively regulated TLR4 signaling in LPS‐stimulated moDCs, leading to strong activation of p38 MAP‐kinase paralleled by increased proinflammatory cytokine and IFN‐β production. In contrast, lovastatin promoted negative regulation of IFN‐β‐mediated autocrine signaling through the IFN‐αβ receptor, paralleled by low expression of the transcription factor IRF‐1, leading to the inhibition of the enzymes iNOS and HO‐1. Defective activation of iNOS/HO‐1 resulted in limited cytoprotective capacity against ROS and reduced microbicidal potential. These data were validated using an in vivo model of Listeria monocytogenes infection, which revealed that iNOS activation by splenic inflammatory moDCs, specialized in NO and TNF‐α production, was strongly reduced in lovastatin‐treated, Listeria‐infected mice. Statin treatment could have severe implications in immunity against pathogens due to defective iNOS/HO‐1 metabolism activation in inflammatory moDCs that might lead to immune failure.
Selective Copper‐Mediated Halogenation of Aromatic Rings Under Mild Conditions
Authors: Gamba Ilaria , Gamez Patrick , Monzani Enrico , Casella Luigi , Mutikainen Ilpo , Reedijk Jan 
Published: August 2011

AbstractA mild copper‐mediated halogenation reaction of phenolic rings is reported. The reaction of bis(2‐hydroxybenzyl)‐1,3‐diaminopropane (H2bhbd) with copper(II) chloride in acetonitrile generates linear trinuclear [Cu3(bhcbd)2Cl2](CH3CN), containing modified ligands, whose phenol moieties are selectively chlorinated at the 5‐position. Under comparable experimental conditions with copper(II) bromide, bromination of the ligand is observed, albeit at a slower reaction rate. In the presence of trialkylorthoformates, which are used as dehydrating agents, a ring closure of the ligand is observed after removal of copper to yield a product with a six‐membered ring. This product has been isolated and characterized by NMR spectroscopy and MS. Similarly, bromination of bis(2‐hydroxybenzyl)‐1,3‐diiminopropane (H2bhbdi) occurs in the presence of copper(II) bromide, with concomitant formation of a linear trinuclear complex. Surprisingly, an asymmetric dinuclear copper(II) coordination compound without chlorination of the ligand is obtained when the related ligand bis(2‐hydroxybenzyl)‐1,3‐diminopropane (H2bhbdi) reacts with copper(II) chloride.
Four Soft Donors and a Hard Centre: Rhodium Complexes of a Novel Tetrakis(NHC)‐Encapsulated Crown Ether Ligand
Authors: Shrestha Sumi , Gimbert‐Suriñach Carolina , Bhadbhade Mohan , Colbran Stephen B. 
Published: August 2011

Abstract2,3,13,14‐Tetrakis(bromomethyl)dibenzo‐18‐crown‐6 (1) has been demonstrated to be a versatile synthetic intermediate for constructing multinucleating ligands with a hard‐donor, crown ether centre. By using this intermediate, novel salts of tetrakis(imidazoliomethyl)dibenzo‐18‐crown‐6, [H4L1]X4 (2: X– = Br–; 4: X– = PF6–), and tetrakis(benzimidazoliomethyl)dibenzo‐18‐crown‐6, [H4L2]X4 (3: X– = Br–; 5: X– = PF6–), were prepared. These salts are precursors to novel tetrakis(N‐heterocyclic carbene) complexes spanned by a crown ether bridge capable of binding various hard metal ions. Thetetrakis(imidazoliomethyl) salt 4 was used to prepare the bimetallic rhodium complexes [{(cod)Rh}2(μ‐L1)][PF6]2 (6) and [{(CO)2Rh}2(μ‐L1)][PF6]2 (7). These complexes selectively bind alkali metal ions.
Synthesis of pseudo‐telechelic diols by transesterification and thiol‐ene coupling
Authors: Desroches Myriam , Caillol Sylvain , Auvergne Rémi , Boutevin Bernard 
Published: August 2011

AbstractTransesterification of methyl esters of rapeseed oil with ethylene glycol in excess led to a ω‐hydroxy fatty ester with a yield of 90%. 2‐Mercaptoethanol was grafted onto the double bonds of this ω‐hydroxy fatty ester by UV initiated thiol‐ene coupling under mild conditions. Double bond conversion was found to be quantitative and yielded a polyol with average of two primary hydroxyl functions. This pseudo‐diol was characterized by means of NMR spectroscopy, titration and mass spectroscopy (MS) and was used to synthesize polyurethane (PU) by step growth polyaddition with methylene diphenyl‐4,4′‐diisocyanate. The polymer, analyzed by thermogravimetric analysis (TGA) and DSC, showed a glass transition temperature of −3°C, close to the one measured (8°C) on a PU based on a commercial polyol, Desmophen 1150.Practical application: The products of the chemistry described in this contribution, i.e. polyol from vegetable oils derivatives, provide biobased building blocks for further PUs syntheses by reaction with diisocyanates. The obtained PUs are partially biobased and may be applied as binders and coatings.
Porphyrin Dimers and Arrays
Authors: Ryan Aoife , Gehrold Andreas , Perusitti Romain , Pintea Monica , Fazekas Marijana , Locos Oliver B. , Blaikie Frances , Senge Mathias O. 
Published: August 2011

AbstractCurrent applications of porphyrins in medicine and optics, such as photodynamic therapy or nonlinear absorbers, increasingly require the use of far‐red absorbing dyes. Modifications of the porphyrin structure to accommodate these conditions can be achieved by extending the conjugation of the porphyrin π‐system, which causes a bathochromic shift in the absorption spectrum. Thus, conjugated porphyrin oligomers have found widespread use. However, past synthetic strategies have mainly targeted symmetric porphyrin dimers, trimers, and oligomers, which limit the practical use of such chromophores. Here, a series of symmetric and unsymmetric dimeric and trimeric porphyrin systems, which are connected by conjugated linkers, namely alkyne and phenylacetylene, were synthesized by palladium‐catalyzed C–C coupling reactions. Adopting two approaches, firstly, a series of new unsymmetric dimers was synthesized by the incorporation of all substituents on the monomeric components prior to coupling. The second was the synthesis of new symmetric dimers and trimers with free meso positions enabling further chemistry to be carried out. The majority of these conjugated arrays exhibited a bathochromic shift in their UV/Vis absorption, in particular the alkyne‐linked arrays showed absorption greater than 720 nm. The mass spectra of phenylacetylene‐ and diphenylbutadiene‐linked zinc arrays exhibited detachment of zinc from the porphyrin core. These unusual results are both linker and metal dependent, usually only seen for more labile metals.
A Chiral Pool Strategy for the Synthesis of Enantiopure Hydroxymethyl‐Substituted Pyridine Derivatives
Authors: Eidamshaus Christian , Reissig Hans‐Ulrich 
Published: August 2011

AbstractA simple procedure for the synthesis of enantiopure hydroxymethyl‐substituted pyridine derivatives is presented. The developed method is based on TMSOTf‐promoted cyclocondensations of β‐ketoenamides, leading to differently substituted 4‐hydroxypyridine/4‐pyridone derivatives. The required β‐ketoenamides were prepared by acylation ofeasily available enamino ketones with suitably protected enantiopure carboxylic chlorides. Most of the experiments were performed withD‐mandelic acid as starting material. It has been shown that all steps occur essentially without racemisation. Several of the prepared 4‐pyridone derivatives were transformed into the corresponding pyrid‐4‐yl nonaflates and subjected to a series of palladium‐catalysed transformations, such as Suzuki, Heck or Sonogashira reactions. In addition, regioselective side‐chain functionalisation of unsymmetrically 2,6‐disubstituted pyridine derivatives was accomplished by application of Boekelheide rearrangements of the corresponding pyridineN‐oxides. The presented methods allow a flexible, rapid and scalable approach to highly substituted, enantiopure pyridine derivatives.
Asymmetric Copper(II)‐Catalysed Nitroaldol (Henry) Reactions Utilizing a Chiral C1‐Symmetric Dinitrogen Ligand
Authors: Zhou Yirong , Gong Yuefa 
Published: August 2011

AbstractA series of stable chiral C1‐symmetric dinitrogen ligands were conveniently synthesized in high yields by condensation of chiral amines [(–)‐exo‐bornylamine or (+)‐(1S,2S,5R)‐menthylamine] with various substituted imidazolecarbaldehydes. With the assistance of base, the ligand L1 in combination with CuCl2·2H2O (2.5 mol‐% or 5.0 mol‐%) can efficiently promote nitroaldol (Henry) reactions between a variety of aldehydes and nitromethane. Both aromatic and aliphatic aldehydes were tolerated in our catalytic system, affording the expected nitroalcohol products in high yields (up to 97 %) and with good enantioselectivities (up to 96 %) under mild reaction conditions.
Experimental verification of seismic vibration control using a semi‐active friction tuned mass damper
Authors: Lin Ging‐Long , Lin Chi‐Chang , Lu Lyan‐Ywan , Ho Yu‐Bo 
Published: August 2011

SUMMARYA tuned mass damper (TMD) system consists of an added mass with properly functioning spring and damping elements for providing frequency‐dependent damping in a primary structure. The advantage of a friction‐type TMD, that is, a nonlinear TMD, is its energy dissipation via a friction mechanism. In contrast, the disadvantages of a passive friction TMD (PF‐TMD) are its fixed and predetermined slip load and loss of tuning and energy dissipation capabilities when it is in a stick state. A semi‐active friction TMD (SAF‐TMD) is used to overcome these disadvantages. The SAF‐TMD can adjust its slip force in response to structure motion. To verify its feasibility, a prototype SAF‐TMD was fabricated and tested dynamically using a shaking table test. A nonsticking friction control law was used to keep the SAF‐TMD activated and in a slip state in earthquakes at varying intensities. The shaking table test results demonstrated that: (i) the experimental results are consistent with the theoretical results; (ii) the SAF‐TMD is more effective than the PF‐TMD given a similar peak TMD stroke; and (iii) the SAF‐TMD can also prevent a residual TMD stroke in a PF‐TMD system. Copyright © 2011 John Wiley & Sons, Ltd.
An algorithm for the simulation of thermally coupled low speed flow problems
Authors: Ryzhakov Pavel , Rossi Riccardo , Oñate Eugenio 
Published: August 2011

SUMMARYIn this paper, we propose a computational algorithm for the solution of thermally coupled flows in subsonic regime. The formulation is based upon the compressible Navier–Stokes equations, written in nonconservation form. An efficient modular implementation is obtained by solving the energy equation separately and then using the computed temperature as a known value in the momentum‐continuity system. If an explicit single‐step time integration scheme for the energy equation is used, the decoupling results to be natural.Integration of the momentum‐continuity system is carried out using a semi‐explicit method, combining Runge–Kutta and Backward Euler schemes for the momentum and continuity equations, respectively. Implicit treatment of pressure leads to favorable time step estimates even in the low Mach number (Ma ≪ 1) regimes. The numerical dissipation introduced by the Backward Euler scheme ensures absence of the spurious high frequencies in the numerical solution.The key point of the method is the assumption of linear variation of the temperature within a time step. Combined with a fractional splitting of the momentum‐continuity system, it allows to solve the continuity only once per time step. Omitting the necessity of solving for the pressure at every intermediate step of the Runge–Kutta scheme minimizes the computational cost associated to the implicit step and leads to an efficiency close to that of a purely explicit scheme.The method is tested using two benchmark examples.Copyright © 2011 John Wiley & Sons, Ltd.
Engineered nanostructural materials for application in cancer biology and medicine
Authors: Mahmood Meena , Casciano Dan , Xu Yang , Biris Alexandru S. 
Published: August 2011

ABSTRACTNanotechnology covers a wide variety of fields of research, including chemistry, physics, biology and medicine, with extensive applications in cancer, ranging from accurate, early detection of malignant lesions to minimizing metastasis. Continued development of cancer‐targeted therapy has promising advantages: maximizing the effectiveness of anticancer drugs while decreasing the harmful systemic effects; tumor destruction via heating that takes advantage of magnetic nanoparticles' size, magnetization and biocompatibility; novel drug‐delivery systems; and gene therapy functions to facilitate controlled drug loading and release inside the cytoplasm. These and other nanotechnology applications can contribute essential new knowledge in the fight against cancer. Copyright © 2011 John Wiley & Sons, Ltd.