bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomimetic design of chelating interfaces
Authors: Tian Fang , Roman Maxine J. , Decker Eric A. , Goddard Julie M.
Published: July 2014

Siderophores are naturally occurring small molecules with metal binding constants greater than many synthetic chelators. Herein, we report a two‐step process to graft a siderophore‐mimetic metal chelating polymer from a polypropylene (PP) surface. Poly(methyl acrylate) was first grafted from the PP surface by photoinitiated graft polymerization, followed by the conversion into poly(hydroxamic acid) (PHA) to obtain PP‐g‐PHA films. ATR/FTIR, contact angle, SEM, and AFM were performed to characterize surface properties of films. Iron binding kinetics and the influence of pH (3.0–5.0) on the chelating ability of films were determined. PP‐g‐PHA exhibited significant iron chelating activity (∼80 nmol/cm2) with an equilibration time of 24 h. The materials retained 50% chelating ability at pH 3.0 compared with pH 5.0, almost double the retention of previously reported polycarboxylate chelating interfaces. By using siderophore‐mimetic surface chemistry, such effective metal chelating interfaces can extend the applications of metal chelating polymers in environmental remediation, water purification, and active packaging areas. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41231.
Carbon nanomaterial‐based copolymer of styrene–divinylbenzene resins: Efficient interaction through graphene/CNTs polymer network
Authors: Li Yanan , Yu Fengping , He Wenjun , Yang Weimin
Published: July 2014

Carbon nanotubes (CNTs) and graphene were separately incorporated into the cross‐linked network of styrene–divinylbenzene composites via in situ suspension polymerization. The prepared copolymers were first chloromethylated and then aminated with trimethylamine to obtain ion exchange resins (IERs). The CNTs‐based and graphene‐based composites exhibited good dispersion throughout the polymer matrix with strong interaction within the network. Remarkable enhancement in antiswelling properties and thermal stabilities confirmed that graphene showed better compatibility and stronger interfacial adhesion than CNTs. The structural and thermal properties of the CNTs‐based and graphene‐based IERs were also significantly improved even at low loadings of 0.4 wt % compared with those when no CNTs and graphene were added. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41234.
Poly(amino ether)/organoclay nanocomposites: Preparation and characterization
Authors: Granado Ainhoa , Eguiazábal Jose Ignacio
Published: July 2014

Dispersed polymer nanocomposites based on a poly(amino ether) resin and organically modified laminar clays were obtained. The chemical nature of the organic modifier of the clay and the processing temperature were first chosen using Young's modulus of the nanocomposites as a measure of the dispersion level. The Cloisite® 20A organoclay and a processing temperature of 170°C were the fixed parameters. Additionally, the clay content of the nanocomposites was changed and their nanostructure and properties were measured. A significant increase in the modulus of elasticity (35% with 4.3% montmorillonite addition) was observed, together with an unusual increase in ductility. The ductility behavior is attributed to a high degree of confinement of polymer chains inside the silicate layers, and the modulus values are discussed taking into account not only the dispersion level, but also the length of the clay particles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41239.
Flame retardation of dibromoneopentyl glycol on intumescent flame‐retardant/low‐density polyethylene composites
Authors: Ma Zhi‐Ling , Wang Xian‐Ling , Wei Hui‐Mian , Song Hong‐Zan
Published: July 2014

On the basis of ammonium polyphosphate (APP) microencapsulated with pentaerythritol/dibromoneopentyl glycol (DBNPG) mixed phosphate melamine salt as an intumescent flame retardant (IFR), the influence of DBNPG on the flame retardancy of IFR/low‐density polyethylene was investigated. The results prove that DBNPG could influence the combustion heat and the thermal barrier properties of the char layer in combustion. The intumescent degree (ID), compactness, and closure were the determinants of the thermal barrier properties of the char layer. A greater ID below 500°C and then a more compact and closed char layer above 500°C contributed to the better thermal barrier properties. An appropriate DBNPG reduced the combustion heat and promoted the formation of a compact and closed char layer by increasing of the melting viscosity of the composites. However, excessive DBNPG destroyed the closure of the char layer and increased the combustion heat because of a decrease in the melting viscosity of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41244.
The Politics of Tax Reform in Australia
Authors: Hewson John
Published: July 2014

Increasingly short‐term, opportunistic, adversarial politics has consistently constrained and compromised significant and genuine tax reform in Australia. This article reviews the various attempts at tax reform since Asprey in the mid‐1970s, assesses the existing tax system and attempts to set out the major essential ingredients of genuine tax reform in this country. Tax reform is seen as particularly urgent.
Methotrexate Inhibits NF‐κB Activity Via Long Intergenic (Noncoding) RNA–p21 Induction
Authors: Spurlock Charles F. , Tossberg John T. , Matlock Brittany K. , Olsen Nancy J. , Aune Thomas M.
Published: July 2014

Objective

To determine interrelationships between the expression of long intergenic (noncoding) RNA–p21 (lincRNA‐p21), NF‐κB activity, and responses to methotrexate (MTX) in rheumatoid arthritis (RA) by analyzing patient blood samples and cell culture models.

Methods

Expression levels of long noncoding RNA and messenger RNA (mRNA) were determined by quantitative reverse transcription–polymerase chain reaction. Western blotting and flow cytometry were used to quantify levels of intracellular proteins. Intracellular NF‐κB activity was determined using an NF‐κB luciferase reporter plasmid.

Results

Patients with RA expressed reduced basal levels of lincRNA‐p21 and increased basal levels of phosphorylated p65 (RelA), a marker of NF‐κB activation. Patients with RA who were not treated with MTX expressed lower levels of lincRNA‐p21 and higher levels of phosphorylated p65 compared with RA patients treated with low‐dose MTX. In cell culture using primary cells and transformed cell lines, MTX induced lincRNA‐p21 through a DNA‐dependent protein kinase catalytic subunit (DNA PKcs)–dependent mechanism. Deficiencies in the levels of PRKDC mRNA in patients with RA were also corrected by MTX in vivo. Furthermore, MTX reduced NF‐κB activity in tumor necrosis factor α–treated cells through a DNA PKcs–dependent mechanism via induction of lincRNA‐p21. Finally, we observed that depressed levels of TP53 and lincRNA‐p21 increased NF‐κB activity in cell lines. Decreased levels of lincRNA‐p21 did not alter NFKB1 or RELA transcripts; rather, lincRNA‐p21 physically bound to RELA mRNA.

Conclusion

Our findings support a model whereby depressed levels of lincRNA‐p21 in RA contribute to increased NF‐κB activity. MTX decreases basal levels of NF‐κB activity by increasing lincRNA‐p21 levels through a DNA PKcs–dependent mechanism.
Supramolecular Phosphatases Formed by the Self‐Assembly of the Bis(Zn2+–Cyclen) Complex, Copper(II), and Barbital Derivatives in Water
Authors: Zulkefeli Mohd , Hisamatsu Yosuke , Suzuki Asami , Miyazawa Yuya , Shiro Motoo , Aoki Shin
Published: July 2014

In our previous paper, we reported that a dimeric Zn2+ complex with a 2,2′‐bipyridyl linker (Zn2L1), cyanuric acid (CA), and a Cu2+ ion automatically assemble in aqueous solution to form 4:4:4 complex 3, which selectively catalyzes the hydrolysis of mono(4‐nitrophenyl)phosphate (MNP) at neutral pH. Herein, we report that the use of barbital (Bar) instead of CA for the self‐assembly with Zn2L1 and Cu2+ induces 2:2:2 complexation of these components, and not the 4:4:4 complex, to form supramolecular complex 6 a, the structure and equilibrium characteristics of which were studied by analytical and physical measurements. The finding show that 6 a also accelerates the hydrolysis of MNP, similarly to 3. Moreover, inspired by the crystal structure of 6 a, we prepared barbital units that contain functional groups on their side chains in an attempt to produce supramolecular phosphatases that possess functional groups near the Cu2(μ‐OH)2 catalytic core so as to mimic the catalytic center of alkaline phosphatase (AP).
A reflectometric interferometric nanosensor for sarcosine
Authors: Diltemiz Sibel Emir , Uslu Okan
Published: July 2014

Sarcosine was recently identified as a differential metabolite that is present in urine in elevated concentration as prostate cancer develops metastases. The aim of this study is to prepare reflectometric interference spectroscopy (RIfS) nanosensors for the detection of sarcosine. Sarcosine imprinted nanoparticles were prepared by two phase miniemulsion polymerization and characterized with transmission electron microscopy, dynamic light scattering, and atomic force microscopy measurements. The glass substrates (10 × 10 mm2) were treated with Piranha solution and incubated in polyethyleneimine solution. The sarcosine imprinted nanoparticles were attached to glass substrates by spin coating of nanoparticle solution. The recognition properties of the nanosensors were evaluated by reflectometric interferometric spectroscopy. To show selectivity of sarcosine imprinted RIfS nanosensor, real‐time l‐alanine detection was also performed. Sarcosine detection studies were performed from aqueous solution and urine sample. A good linearity was revealed with a correlation coefficient of 0.9622 and a detection limit of 45 nM. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:55–61, 2015
Epidemic based modeling of enzymatic hydrolysis of lignocellulosic biomass
Authors: Tai Chao , Arellano Maria G. , Keshwani Deepak R.
Published: July 2014

An epidemic based model was developed to describe the enzymatic hydrolysis of a lignocellulosic biomass, dilute sulfuric acid pretreated corn stover. The process of substrate getting adsorbed and digested by enzyme was simulated as susceptibles getting infected by viruses and becoming removed and recovered. This model simplified the dynamic enzyme “infection” process and the catalysis of cellulose into a two‐parameter controlled, enzyme behavior guided mechanism. Furthermore, the model incorporates the adsorption block by lignin and inhibition effects on cellulose catalysis. The model satisfactorily predicted the enzyme adsorption and hydrolysis, negative role of lignin, and inhibition effects over hydrolysis for a broad range of substrate and enzyme loadings. Sensitivity analysis was performed to evaluate the incorporation of lignin and other inhibition effects. Our model will be a useful tool for evaluating the effects of parameters during hydrolysis and guide a design strategy for continuous hydrolysis and the associated process control. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1021–1028, 2014
Analysis of biomarkers for risk of acute kidney injury after primary angioplasty for acute ST‐segment elevation myocardial infarction: Results of the HORIZONS‐AMI trial
Authors: Guerchicoff Alejandra , Stone Gregg W. , Mehran Roxana , Xu Ke , Nichols Dru , Claessen Bimmer E. , Guagliumi Giulio , Witzenbichler Bernhard , Henriques José P.S. , Dangas George D.
Published: July 2014

Objectives

Contrast‐induced acute kidney injury (CI‐AKI) may occur after percutaneous coronary intervention (PCI).

Methods

We evaluated patients with ST‐elevation myocardial infarction (STEMI) undergoing emergency PCI with serial biomarkers.

Results

Of the 390 patients enrolled in the HORIZONS‐AMI biomarker substudy, 56 (14.3%) developed AKI. In the AKI group, the levels of B‐type natriuretic peptide were consistently higher than in the no‐AKI group at baseline (P = 0.0327), hospital discharge (P = 0.0002), 30‐day follow‐up (P = 0.0193), and 1‐year follow‐up (P = 0.031). At hospital discharge, the AKI group had elevated biomarkers compared to the no‐AKI group: D‐dimer (P = 0.0066), C‐reactive protein (P = 0.0468), endothelial cell‐selective adhesion molecule (P = 0.0169), adiponectin (P = 0.0346), and von Willebrand factor (P = 0.0168); there was also a trend toward higher cystatin C (P = 0.0585) in the AKI group. Similar correlations between biomarker panel increase and the development of CI‐AKI were consistent at baseline, 30‐day, and 1‐year follow‐up. Chemokine (C‐C motif) ligand 23 showed an opposite pattern with an increase at all time points in the no‐AKI compared to the AKI group.

Conclusions

The risk of CI‐AKI after primary PCI for STEMI may be associated with hemostatic imbalances, activation of procoagulants, decreased endogenous anticoagulants, enhanced inflammation, platelet activation, or decreased fibrinolytic activity. © 2014 Wiley Periodicals, Inc.
Synthesis and Activity of Plasmonic Photocatalysts
Authors: Lou Zaizhu , Wang Zeyan , Huang Baibiao , Dai Ying
Published: July 2014

Plasmonic photocatalysts, which have intensive light absorption and high charge‐separation efficiencies, are regarded as promising candidates to solve energy and environmental issues in the future. In this Review, we summarize recent developments in the synthesis, activity, and mechanism of plasmonic photocatalysts, with the aim of stimulating improvements in photocatalytic activities and promoting the development of photocatalysis. The materials systems, energy‐transfer mechanisms, and factors that influence the photocatalytic activities of plasmonic photocatalysts are discussed. Some perspectives for the future development of the design of highly efficient plasmonic photocatalysts are proposed.
Effect of Temperature on Fluidization Regimes
Authors: Hagh‐Shenas‐Lari Mohammad‐Javad , Mostoufi Navid
Published: July 2014

The probability of fluidization regimes at high temperature was determined experimentally by frequency domain analysis of pressure fluctuations. Fluidization regime probabilities were calculated for various gas velocities and temperatures. By increasing the temperature, larger bubbles became more stable which resulted in postponing transition from bubbling to turbulent fluidization. Results showed that the transition velocity from bubbling to turbulent increases by raising the temperature. A probability model was proposed and compared with experimental data indicating good accordance.
Gold(III) Chloride Catalyzed Synthesis of Chiral Substituted 3‐Formyl Furans from Carbohydrates: Application in the Synthesis of 1,5‐Dicarbonyl Derivatives and Furo[3,2‐c]pyridine
Authors: Mal Kanchan , Sharma Abhinandan , Das Indrajit
Published: July 2014

This report describes a gold(III)‐catalyzed efficient general route to densely substituted chiral 3‐formyl furans under extremely mild conditions from suitably protected 5‐(1‐alkynyl)‐2,3‐dihydropyran‐4‐one using H2O as a nucleophile. The reaction proceeds through the initial formation of an activated alkyne–gold(III) complex intermediate, followed by either a domino nucleophilic attack/anti‐endo‐dig cyclization, or the formation of a cyclic oxonium ion with subsequent attack by H2O. To confirm the proposed mechanistic pathway, we employed MeOH as a nucleophile instead of H2O to result in a substituted furo[3,2‐c]pyran derivative, as anticipated. The similar furo[3,2‐c]pyran skeleton with a hybrid carbohydrate–furan derivative has also been achieved through pyridinium dichromate (PDC) oxidation of a substituted chiral 3‐formyl furan. The corresponding protected 5‐(1‐alkynyl)‐2,3‐dihydropyran‐4‐one can be synthesized from the monosaccharides (both hexoses and pentose) following oxidation, iodination, and Sonogashira coupling sequences. Furthermore, to demonstrate the potentiality of chiral 3‐formyl furan derivatives, a TiBr4‐catalyzed reaction of these derivatives has been shown to offer efficient access to 1,5‐dicarbonyl compounds, which on treatment with NH4OAc in slightly acidic conditions afforded substituted furo[3,2‐c]pyridine.
Palladium‐Catalyzed Chemoselective Allylic Substitution, Suzuki–Miyaura Cross‐Coupling, and Allene Formation of Bifunctional 2‐B(pin)‐Substituted Allylic Acetate Derivatives
Authors: Kim Byeong‐Seon , Hussain Mahmud M. , Hussain Nusrah , Walsh Patrick J.
Published: July 2014

A formidable challenge at the forefront of organic synthesis is the control of chemoselectivity to enable the selective formation of diverse structural motifs from a readily available substrate class. Presented herein is a detailed study of chemoselectivity with palladium‐based phosphane catalysts and readily available 2‐B(pin)‐substituted allylic acetates, benzoates, and carbonates. Depending on the choice of reagents, catalysts, and reaction conditions, 2‐B(pin)‐substituted allylic acetates and derivatives can be steered into one of three reaction manifolds: allylic substitution, Suzuki–Miyaura cross‐coupling, or elimination to form allenes, all with excellent chemoselectivity. Studies on the chemoselectivity of Pd catalysts in their reactivity with boron‐bearing allylic acetate derivatives led to the development of diverse and practical reactions with potential utility in synthetic organic chemistry.
Base‐Promoted C→N Acyl Rearrangement: An Unconventional Approach to α‐Amino Acid Derivatives
Authors: Ugarriza Iratxe , Uria Uxue , Carrillo Luisa , Vicario Jose L. , Reyes Efraim
Published: July 2014

We have discovered that N‐alkyl aminomalonates undergo a fast and selective intramolecular C→N acyl rearrangement reaction in the presence of a strong base, leading to N‐protected glycinates in excellent yield. Moreover, the fact that the reaction proceeds through a nucleophilic enolate intermediate has been used for implementing a tandem rearrangement/alkylation sequence that has been applied to the preparation of synthetically relevant nonproteinogenic tertiary and quaternary N‐alkyl α‐amino acids in a very simple and reliable way.
A Magnetically Drivable Nanovehicle for Curcumin with Antioxidant Capacity and MRI Relaxation Properties
Authors: Magro Massimiliano , Campos René , Baratella Davide , Lima Giuseppina , Holà Katerina , Divoky Clemens , Stollberger Rudolf , Malina Ondrej , Aparicio Claudia , Zoppellaro Giorgio , Zbořil Radek , Vianello Fabio
Published: July 2014

Curcumin possesses wide‐ranging anti‐inflammatory and anti‐cancer properties and its biological activity can be linked to its potent antioxidant capacity. Superparamagnetic maghemite (γ‐Fe2O3), called surface‐active maghemite nanoparticles (SAMNs) were surface‐modified with curcumin molecules, due to the presence of under‐coordinated FeIII atoms on the nanoparticle surface. The so‐obtained curcumin‐modified SAMNs (SAMN@curcumin) had a mean size of 13±4 nm. SAMN@curcumin was characterized by transmission and scanning electron microscopy, UV/Vis, FTIR, and Mössbauer spectroscopy, X‐ray powder diffraction, bulk susceptibility (SQUID), and relaxometry measurements (MRI imaging). The high negative contrast proclivity of SAMN@curcumin to act as potential contrast agent in MRI screenings was also tested. Moreover, the redox properties of bound curcumin were probed by electrochemistry. SAMN@curcumin was studied in the presence of different electroactive molecules, namely hydroquinone, NADH and ferrocyanide, to assess its redox behavior. Finally, SAMN@curcumin was electrochemically probed in the presence of hydrogen peroxide, demonstrating the stability and reactivity of bound curcumin.
Synthesis and Characterization of a Family of POCOP Pincer Complexes with Nickel: Reactivity Towards CO2 and Phenylacetylene
Authors: Jonasson Klara J. , Wendt Ola F.
Published: July 2014

A cyclohexyl‐based POCOP pincer ligand (POCOP=cis‐1,3‐bis(di‐tert‐butylphosphinito)cyclohexyl) cyclometalates with nickel to generate a series of new POCOP‐supported NiII complexes, including the halide, hydride, methyl, and phenyl species. trans‐[NiCl{cis‐1,3‐bis(di‐tert‐butylphosphinito)cyclohexane}], [(POCOP)NiCl] (1 a) and the analogous bromide complex (1 b) were synthesized and fully characterized by NMR spectroscopy and X‐ray crystallography. Cyclic voltammetry measurements of 1 a and 1 b alongside their bis(phosphine) analogues [(PCP)NiCl] (2 a) and [(PCP)NiCl] (2 a) (PCP=cis‐1,3‐bis(di‐tert‐butylphosphino)cyclohexyl) indicate a reduced electron density at the metal center upon introducing electron‐withdrawing oxygen atoms in the pincer arms. The methyl [(POCOP)NiMe] (3) and phenyl [(POCOP)NiPh] (4) complexes were formed from 1 a by reaction with the corresponding organolithium reagents. 1 a also reacts with LiAlH4 to give the hydride complex [(POCOP)NiH] (5). The methyl complex 3 reacts with phenyl acetylene to give the acetylide complex [(POCOP)NiCCPh] (6). The reactivity of compounds 3–5 towards CO2 was studied. The hydride complex 5 and the methyl complex 3 both underwent CO2 insertion to form the formate species [(POCOP)NiOCOH] (7) and acetate species [(POCOP)NiOCOCH3] (8), respectively, although with a higher barrier of insertion in the latter case. Compound 4 was unreactive towards CO2 even at elevated temperatures. Complexes 3–8 were all characterized by NMR spectroscopy and X‐ray crystallography.
Spindle‐Like Polypyrrole Hollow Nanocapsules as Multifunctional Platforms for Highly Effective Chemo–Photothermal Combination Therapy of Cancer Cells in Vivo
Authors: Wang Yang , Xiao Yun , Tang Ruikang
Published: July 2014

The monodispersed spindle‐like polypyrrole hollow nanocapsules (PPy HNCs) as the multifunctional platforms for combining chemotherapy with photothermal therapy for cancer cells are reported. Whereas the hollow cavity of nanocapsules can be used to load the anticancer drug (i.e., doxorubicin) for chemotherapy, the PPy shells can convert NIR light into heat for photothermal therapy. The release of the drug from the spindle‐like PPy HNCs is pH‐sensitive and near‐infrared (NIR) light‐enhanced. More importantly, the spindle‐like PPy HNCs can penetrate cells more rapidly and efficiently in comparison with the spherical PPy HNCs. Both in vitro and in vivo experiments demonstrated that the combination of DOX‐loaded spindle‐like PPy HNCs and NIR light provide a highly effective and feasible chemo‐photothermal therapy cancer method with a synergistic effect. Owing to their high photothermal conversion efficiency, large hollow cavity, and good biocompatibility, the spindle‐like PPy HNCs could be used as a promising new cancer drug‐nanocarrier and photothermal agent for localized tumorous chemo‐photothermal therapy.
Naphthocrown‐Strapped Calix[4]pyrroles: Formation of Self‐Assembled Structures by Ion‐Pair Recognition
Authors: Kim Sung Kuk , Lee Hong Gyu , Vargas‐Zúñiga Gabriela I. , Lynch Vincent M. , Kim Cheal , Sessler Jonathan L.
Published: July 2014

A new approach to the construction of self‐assembled structures is reported that is based on ion‐pair recognition. Towards this end, the calix[4]pyrrole naphthocrown‐4 hybrid structures 2 and 3 were prepared. These multitopic receptors contain recognition sites for both anions and cations. On the basis of solution‐phase 1H NMR spectroscopic analysis and solid‐state single‐crystal X‐ray diffraction structural studies, it was established that receptors 2 and 3 are able to bind specific ion pairs with high selectivity via different binding modes. In the case of CsF and CsCl, the ion‐pair complexes formed from receptors 2 and 3 were found to self‐assemble to produce either linear supramolecular polymeric crystalline solids or nanotube‐like cyclic hexamers depending on the specific choice of ion pairs and crystallization solvents. Proton NMR studies provided evidence for solution‐phase self‐association in organic media.
Conditioning of Dry Lignite for Continuous Feeding with a Slurry Pump into Novel Pressurized Gasifiers
Authors: Rosin Alexander , Schröder Hans‐Werner , Repke Jens‐Uwe
Published: July 2014

Eintragssysteme für Braunkohle in neuartige Hochdruckvergaser sollten nicht nur kontinuierlich arbeiten und eine vollkommene Abdichtung gegenüber dem Reaktor sichern, sondern auch zu einer deutlichen Verbesserung des energetischen Wirkungsgrades des Vergasungsprozesses führen. Ein potenzieller Lösungsansatz ist der Einsatz von Dickstoffpumpen, die Feuchtstoffe mit hohem Feststoffgehalt fördern können. Ihre Verwendung ist jedoch nur mit entsprechend modifizierter Braunkohle möglich. In den durchgeführten Untersuchungen werden verschiedene Konditionierungsmethoden aufgezeigt.
Direct Determination of Sulfur in Coal by Electrothermal Vaporization Coupled with Optical Emission Spectrometry
Authors: Bauer Daniela , Vogt Thomas , Lehmann Franz , Otto Matthias
Published: July 2014

Die direkte Feststoff‐Multielementanalytik von Kohle und deren Konversionsprodukten mittels elektrothermischer Verdampfung in Verbindung mit einem Atomemissionsspektrometer mit induktiv gekoppeltem Plasma (ETV‐ICP OES) wird am Beispiel der Schwefelbestimmung dargestellt. Zusätzlich zur Gesamtgehaltsbestimmung ist eine Aussage über das Freisetzungsverhalten des Schwefels, basierend auf der kontrollierten thermischen Zersetzung der Probe in Argonatmosphäre und unter Normaldruck möglich. Dies könnte die Grundlage für eine temperaturabhängige Schwefelspeziation darstellen.
Modelling and simulation of carbon dioxide absorption by aqueous MEA solution in hollow fibre membrane contactors
Authors: Memardoost Saber , Hashemi Aref , Molaei Dehkordi Asghar
Published: July 2014

In this article, a comprehensive model has been developed for analyzing the transport phenomena in hollow fibre membrane contactors operated under non‐wetted or partially wetted conditions. In this regard, the dynamic behaviour of membrane contactors, considering the entrance regions of momentum, thermal energy, and mass transfers, was investigated carefully. Moreover, effects of temperature distribution on the contactor efficiency were examined by taking into account the influences of heat of solution, heat of reaction, and the viscous dissipation. The chemical system studied was a gas sweetening process, including methane and carbon dioxide as the gaseous mixture, and MEA aqueous solution as the solvent. CFD techniques have been used to solve the nonlinear governing equations simultaneously, and the model predictions were validated against reported experimental data in the literature, and excellent agreement was found. Comparing the model predictions with those of previous models shows relatively better accuracy of the model predictions. Furthermore, distributions of velocity, temperature, and species concentrations in the tube side, shell side, and the membrane were obtained and the effects of various operating and design parameters such as wetting fraction, gas and liquid inlet velocities, inlet temperature of the solvent, MEA concentration, and CO2 volume fraction of the feed on these distributions were carefully studied. Finally, the dynamic response of the system was investigated by analyzing the contactor's response to different step and pulse changes.
Effects of calcium monohydrogenphosphate on the morphology of calcium sulfate whisker by hydrothermal synthesis
Authors: Lü Pengfei , Fei Dejun , Dang Yagu
Published: July 2014

In this paper, the factors related to the morphology of calcium sulfate whisker (CSW) are discussed. Most attention was devoted to the influence of co‐crystallized phosphorus in phosphogypsum—existing in the form of CaHPO4 · 2H2O—on the crystal growth, which was ignored in the preparation of CSW from phosphogypsum in previous research. Methods including X‐ray powder diffraction and scanning electron microscopy were performed to characterize the resultant crystals. The CSWs with uniform morphology were prepared by hydrothermal synthesis with commercial CaSO4 · 2H2O. However, the productions from the pretreatment phosphogypsum by hydrothermal synthesis appeared as irregular crystals with a small length to width ratio, and whisk‐broom‐like crystals were common. The influence of CaHPO4 · 2H2O on the growth of CSW has also been studied. The results showed that CaHPO4 · 2H2O can promote the formation of needle‐like crystals and whisk‐broom‐like crystals at hydration condition. In order to improve the morphology of CSW in a CaSO4 · 2H2O‐CaHPO4 · 2H2O system, substantive condition experiments were carried out, and it finally revealed that Fe3+ was useful for the well‐developed CSW.
Numerical computer algorithm for pore size distribution analysis of activated carbons based on local density functional theory
Authors: Moosavi Elham S. , Rezaei Nader , Karimzadeh Ramin
Published: July 2014

A numerical computer algorithm is presented here using local density functional theory (DFT) to analyze pore size distribution (PSD) of activated carbons. Density profiles of adsorbate molecules in adsorbent pores are calculated, and then the adsorbent's PSD is characterized accordingly. Considering that most available DFT‐based software programs report only the PSD results, details of DFT solution procedure is investigated and represented as a numerical algorithm here for the first time. PSD of a granular activated carbon (HD4000) was calculated based on the proposed algorithm, the result of which indicates a similar trend and behaviour with that obtained by DFT PLUS software of Micromeritics ASAP 2010. Also, the activated carbon isotherm evaluated by the proposed algorithm fit the experimental data with a higher accuracy than that estimated by DFT PLUS at lower relative pressures (<0.001).
Efficient strategies to enhance gold leaching during cyanidation of multi‐sulfidic ores
Authors: Azizi Abdelaziz , Olsen Caroline , Larachi Faïçal
Published: July 2014

The high reactivity of sulfide minerals in alkaline cyanide solutions makes gold cyanidation a multifactorial process controlled by the mineralogy of the host rock and where gold recovery is a complex outcome from gold surface passivation, galvanic interactions between the conducting phases (i.e., Au‐sulfide and sulfide‐sulfide) present in multi‐sulfidic ores and excess cyanide and oxygen consumptions. In this study, we highlight a new methodology using a multilayer packed‐bed gold cyanidation reactor to discriminate the role of gold associations and ore mineralogy in multi‐sulfidic‐ore cyanidation. The proposed system also allows for the investigation of the effects of pre‐oxidation and leads addition strategies and their impact on gold leaching rate in the presence of galvanically associated sulfide‐sulfide systems.
UVC based advanced oxidation for decolourization and mineralization of calconcarboxylic acid in aqueous solution: Eco‐toxicological effect of post treated solutions and its remedy
Authors: Sahoo Mihir K. , Sinha Bhauk , Sharan Rajesh. N.
Published: July 2014

The present study reports two important aspects of wastewater treatment by UVC light (λ = 254 nm) in the presence of hydrogen peroxide (HP) and ammonium persulphate (APS) taking Calconcarboxylic acid (CCA) as a model pollutant. The first part deals with the effect of various operational parameters on the decolourization and mineralization of CCA. Most importantly, the eco‐toxicological effect of the treated solutions was examined on the basis of E. coli growth inhibition bioassay and the remedy for the same has been suggested in the second part. Although both oxidants show higher mineralization at pH 1, APS is preferred over HP for having higher mineralization, biodetoxification, and electrical energy efficiency. The presence of –COOH group in CCA has detrimental effect on its mineralization and biodetoxification, as well as on the electrical energy efficiency. Although a rise in mineralization at all pH is observed by the removal of the –COOH group, it is significant in alkaline media. Since treatment at pH 1 is not ideal for real scale applications, it is advisable to remove the –COOH group before treatment, so as to make treatment possible in alkaline media. Removal of –COOH group also leads to higher biodetoxification in a shorter treatment period.
An extensive simulation of coal gasification in bubbling fluidized bed: Integration of hydrodynamics into reaction modelling
Authors: Esmaili Ehsan , Mahinpey Nader , Mostafavi Ehsan
Published: July 2014

The simulation of the coal gasification process in a bubbling fluidized bed reactor was performed in order to estimate the performance of the gasifier and assess the optimal operating conditions. A Eulerian‐Eulerian computational fluid dynamics (CFD) simulation has been developed to predict the hydrodynamic behaviour of the fluidization regime in the bed. This not only provides insight into the hydrodynamics of the bubbling fluidized bed reactor, but also yields hydrodynamics parameters, such as bubble diameter and velocity, solid volume fraction, velocity of gas and solid particles, which can be subsequently used for reaction modelling of the coal gasification process. The predicted hydrodynamic parameters from the CFD simulation are integrated into the kinetics of gasification chemical reactions taking place in the bubble, cloud, and emulsion phases. Instantaneous devolatilization and drying of the feedstock are also considered in the model. The comparison of the predicted results with experimental measurements showed that most of the predicted molar gas compositions in the produced gas were within 15 % of the experimental data. The model was further used to predict the performance of the gasifier at different operating conditions. The results indicated that the temperature range of 800–850 °C, steam‐to‐coal ratios of 0.5–1.5 kg/kg, and air‐to‐coal ratios of 2.0–2.5 kg/kg are suitable conditions for syngas (hydrogen and carbon monoxide, H2 + CO) production. Depending on the application of the produced syngas, the required H2‐to‐CO ratio can be achieved by controlling the air‐ and steam‐to‐coal ratios.
Seismic Wave Dispersion Effects and Inverse Q‐Filter Phase Compensation
Authors: Gu‐Lan ZHANG , Zhen‐Hua HE , Xi‐Ming WANG , Jian‐Jun ZHANG , Yan‐Bin ZHANG , Fei LI
Published: July 2014

Based on the expression of amplitude attenuation and phase velocity dispersion proposed by Futterman, and considering the well‐seismic matching, we derived the expression of seismic wave velocity dispersion between phase velocity and amplitude spectrum for the following four cases: without inverse Q‐filter, with only inverse Q‐filter amplitude compensation, with only inverse Q‐filter phase compensation, with inverse Q‐filter phase and amplitude compensation. We explained the necessity of inverse Q‐filter phase compensation in theory. Through the zero‐offset VSP data example of dynamite and vibroseis source with the same acquisition geometry, we verified the velocity dispersion expression derived in this paper. Through the example of well‐seismic calibration, we further illustrated that inverse Q‐filter phase compensation can effectively eliminate seismic wave velocity dispersion, enhance well‐seismic matching, finally improve the reliability of surface seismic data.
Stress Build‐up in the Shallow Crust Before the Lushan Earthquake Based on the in Situ Stress Measurements
Authors: Cheng‐Hu WANG , Cheng‐Ke SONG , Qi‐Liang GUO , Yan‐Shan ZHANG , Jian‐Min DING
Published: July 2014

The 2013 Ms7.0 Lushan earthquake in Sichuan Province, China, was extremely destructive. Earthquake analysis using stress build‐up in the upper crust is useful for understanding seismogenic mechanisms. In situ stress data from 22 boreholes show that the stress regime is reverse faulting, and indicate that the stress state in the area is relatively stable. The ratio of the half maximum differential stress to the mean effective stress, μm, is employed to reflect the capability and stress build‐up level of the upper crust. μm ranges from 0.39 to 0.56, approaching the lower limit defined by the Byerlee law, which agrees well with laboratory measurements of static friction coefficients. The occurrence of the Lushan earthquake proves that the upper crust in the area is in a critical frictional equilibrium or sub‐equilibrium state. The Lushan earthquake may have been induced by stress increase on the Longmenshan fault from the Wenchuan earthquake.
Reirradiation of recurrent medulloblastoma: Does clinical benefit outweigh risk for toxicity?
Authors: Wetmore Cynthia , Herington Danielle , Lin Tong , Onar‐Thomas Arzu , Gajjar Amar , Merchant Thomas E.
Published: July 2014

BACKGROUND

Patients with recurrent medulloblastoma (MB) have a dismal prognosis. There has been a reluctance to use radiation in the salvage therapy regimens for these patients because of concerns about toxicity and unknown efficacy. Comparing survival outcomes and toxicities in relapsed patients treated with and without radiation may help to define its role.

METHODS

A retrospective review was conducted that included 38 patients with recurrent MB treated with similar risk‐adapted therapy at initial diagnosis; reirradiation was a component of salvage therapy in 14. Overall survival (OS) and toxicity were evaluated according to the use of radiation, prior risk stratification, and other factors.

RESULTS

For relapsed standard‐risk patients, the use of additional irradiation resulted in a statistically significant improvement in OS from initial diagnosis (P = .036), with 5‐ and 10‐year OS rates of 55% ± 14% and 33% ± 16% versus 46% ± 14% and 0% for reirradiated patients versus others, respectively. Similar improvement was observed in high‐risk patients (P = .003). There was an association between the use of additional irradiation and an increased rate of necrosis as determined by neuroimaging (P = .0468).

CONCLUSIONS

The use of irradiation as a component of salvage therapy for relapsed MB may prolong survival. The benefit appears to be greatest for relapsed standard‐risk patients. Cancer 2014;120:3731–3737. © 2014 American Cancer Society.
Asymmetric communication models for resource‐constrained hierarchical ethernet networks
Authors: Zhu Jun , Lastovetsky Alexey , Ali Shoukat , Riesen Rolf , Hasanov Khalid
Published: July 2014

Communication time prediction is critical for parallel application performance tuning, especially for the rapidly growing field of data‐intensive applications. However, making such predictions accurately is non‐trivial when contention exists on different components in hierarchical networks. In this article, we derive an ‘asymmetric network property’ on transmission control protocol (TCP) layer for concurrent bidirectional communications in a commercial off‐the‐shelf (COTS) cluster and develop a communication model as the first effort to characterize the communication times on hierarchical Ethernet networks with contentions on both network interface card and backbone cable levels. We develop a micro‐benchmark for a set of simultaneous point‐to‐point message‐passing interface (MPI) operations on a parametrized network topology and use it to validate our model extensively and show that the model can be used to predict the communication times for simultaneous MPI operations (both point‐to‐point and collective communications) on resource‐constrained networks effectively. We show that if the asymmetric network property is excluded from the model, the communication time predictions will be significantly less accurate than those made by using the asymmetric network property. In addition, we validate the model on a cluster of Grid5000 infrastructure, which is a more loosely coupled platform. As such, we advocate the potential to integrate this model in performance analysis for data‐intensive parallel applications. Our observation of the performance degradation caused by the asymmetric network property suggests that some part of the software stack below TCP layer in COTS clusters needs targeted tuning, which has not yet attracted any attention in literature. Copyright © 2014 John Wiley & Sons, Ltd.
Exploration/exploitation of a hybrid‐enhanced MPSO‐GA algorithm on a fused CPU‐GPU architecture
Authors: Franz Wayne , Thulasiraman Parimala , Thulasiram Ruppa K.
Published: July 2014

Recent work in metaheuristic algorithms has shown that solution quality may be improved by composing algorithms with orthogonal characteristics. At the same time, fused CPU‐GPU systems have emerged as a unique platform on which to study these algorithms. Using metaheuristic algorithms requires striking a balance between local and global exploration. There are no governing rules, however, to balance these. In this paper, we study two population‐based metaheuristic algorithms: multi‐swarm particle swarm optimization (MPSO) and genetic algorithms (GAs). We investigate parallel MPSO variants with genetic operators to increase quality: crossover, mutation, swapping, and all three. We develop a hybrid parallel algorithm that combines a slower convergent algorithm (GA) with a faster one (MPSO). The hybrid achieves significant initial improvement in solution quality but no significant difference in the final average fitness. Executing the GA on the GPU requires approximately an order of magnitude less time (0.07–0.18 s) than on the CPU. Our platform is the AMD A8‐3530MX accelerated processing unit that packs four ×86 CPU cores and 80 very long instruction word GPU processing elements. We make effective use of the hierarchical memory structure on the accelerated processing unit, four‐way very long instruction word vectorization, and zero‐copy buffers. Copyright © 2014 John Wiley & Sons, Ltd.
The Fenna–Matthews–Olson Protein Revisited: A Fully Polarizable (TD)DFT/MM Description
Authors: Jurinovich Sandro , Curutchet Carles , Mennucci Benedetta
Published: July 2014

We report a combined molecular dynamics and quantum mechanics (QM)/molecular mechanics (MM) analysis of the excitonic properties of the Fenna–Matthews–Olson (FMO) protein by using a polarizable MM model combined with a time‐dependent density functional theory description. Overall, our results indicate that structural fluctuations, electrostatic interactions, and short‐range quantum effects can significantly modulate the model Hamiltonian parameters (site energies and couplings). We find that the specific interactions with the axial ligand and the hydrogen‐bonded residues are responsible for the energy ladder, with their effects being mainly due to electrostatic interactions, but with short‐range quantum contributions that are not negligible. In addition, a striking modulation of the screening effects experienced by the BChl pairs, due to the heterogeneous polarizability of the FMO and solvent environment, is observed. Finally, we find that the exciton model gives a reliable description of the delocalized excited states in the complex.
Aminoalkyl‐1,1‐bis(phosphinic acids): Stability, Acid–Base, and Coordination Properties
Authors: David Tomáš , Procházková Soňa , Kotek Jan , Kubíček Vojtěch , Hermann Petr , Lukeš Ivan
Published: July 2014

Four geminal bis(phosphinic acids), namely, aminomethylbis(H‐phosphinic acid) (H2L1) and 4‐aminobutyl‐1‐hydroxy‐1,1‐bis(R‐phosphinic acid) with R = H (H2L2), Me (H2L3) and CH2CH2COOH (H4L4), were studied. Their acid–base properties and coordination ability towards Cu2+, Ni2+ and Zn2+ ions were studied by potentiometry, UV/Vis spectroscopy and NMR spectroscopy. The amine group in H2L1 has a lower protonation constant (log Ka = 6.79) than those found for other studied bisphosphinates (log Ka = 10.75–11.05) with distant amine groups. The structure of [Ca(H2L2‐O,O′)(HL2‐O,O′)]Cl revealed an octahedral arrangement of the metal coordination sphere and a linear polymeric structure, which forms through eight‐membered Ca(–O–P–O–)2Ca rings. The structure of [Cu(HL3‐O,O′)2(H2O)]·5H2O shows two chelating bisphosphinate groups in an equatorial O4 environment. The structure of [Cu(H0.5L3‐O,O′)(NO3)0.5]·2.25H2O shows two different coordination environments, one is an elongated tetragonal pyramid, and the other is a trigonal bipyramid with a bidentate nitrate ion.
One‐Pot Multiple Metal–Organic Framework Formation: Concomitant Generation of Structural Isomers or of Drastically Distinct Materials
Authors: Cheansirisomboon Achareeya , Salinas‐Uber Jorge , Massera Chiara , Roubeau Olivier , Youngme Sujittra , Gamez Patrick
Published: July 2014

The solvothermal reaction of 2,5‐dihydroxyterephthalic acid (H2dhtp) and magnesium(II) nitrate in N,N‐dimethylformamide (DMF) led to the simultaneous formation of two structural isomers, namely, the lvt network Mg(dhtp)(dmf)2 (1) and the compound Mg3(dhtp)3(dmf)6·0.75H2O (2) with the pcu α‐Po primitive cubic topology. The same reaction conditions with manganese(II) nitrate and terephthalic acid (H2tp) resulted in the concomitant generation of two drastically different metal–organic frameworks (MOFs), namely, Mn2(tp)2(dmf)2 (3) and [Mn(HCOO)3][NC2H8] (4), in which the formato ligands and N,N‐dimethylammonium cations arise from DMF degradation.
Synthesis and Characterisation of Bridged Titanocene Oxido Complexes and Their Reactions with Water
Authors: Godemann Christian , Barsch Enrico , Spannenberg Anke , Ludwig Ralf , Beweries Torsten
Published: July 2014

The synthesis of two pyridine‐stabilised ansa‐titanocene oxido complexes is described. Oxidation of the titanocene sources Cpb2Ti(η2‐Me3SiC2SiMe3) (Cpb2 = bridged η5‐cyclopentadienyl, 1a and 1b) with nitrous oxide yields corresponding oxido compounds 2a and 2b, respectively, in high yields. These can be hydrolysed to give dihydroxido complexes 3a and 3b, respectively, without the formation of by‐products. The hydrolysis reaction was monitored by means of in situ IR spectroscopy. Hitherto unknown complexes 2a and 2b were fully characterised, and their molecular structures are reported in this paper.
Enantioselective Hydrosilylation of Ketones Catalyzed by a Readily Accessible N‐Heterocyclic Carbene–Ir Complex at Room Temperature
Authors: Shinohara Kanako , Kawabata Shun , Nakamura Hanako , Manabe Yoshiki , Sakaguchi Satoshi
Published: July 2014

A series of functionalized azolium compounds were synthesized from chiral α‐amino acid derivatives such as β‐amino alcohols. Reaction of hydroxy‐amide‐functionalized azolium salts thus obtained with Ag2O afforded N‐heterocyclic carbene‐Ag (NHC–Ag) complexes. Subsequent treatment of the resulting silver compound with [IrCl(cod)]2 yielded monodentate IrCl(cod)(NHC), which was stable in air. The NHC–Ir complex facilitated efficient asymmetric hydrosilylation of ketones using (EtO)2MeSiH under ambient conditions. A chiral ligand containing an isobutyl stereodirecting group was found to be the best ligand for the functionalized NHC–Ir complexes that were examined. A linear relationship was found between the catalyst ee and the product ee. The hydroxy functional group on the NHC ligand side‐arm not only induced stereocontrol but also enhanced the reaction rate.
Controlled Acid‐Mediated Regioselective O‐Desilylations for Multifunctionalization of Cyclodextrins
Authors: Gu Jiamin , Chen Tong , Zhang Ping , Ling Chang‐Chun
Published: July 2014

A highly valuable tri‐/tetra‐functionalization method is reported for cyclodextrin (CD) chemistry by taking advantage of the acid‐sensitivity of the O‐silyl ether group and also the geometry of CD macrocycles. The controlled acid‐mediated O‐desilylations from the easily accessible per‐3,6‐O‐silylated CD derivatives provide unprecedented regioselectivity to differentiate not only primary O‐silyl groups from secondary groups, but also O‐silyl groups of the same type with identical chemical reactivity. This methodology differs from other conventional monofunctionalization methods of natural CDs, which only allow for a direct twofold differentiation of hydroxyl groups in a CD, because the current method permits the synthesis of tri‐ and tetra‐functionalized CDs in a short reaction sequence. Most importantly, the developed method has been found to be applicable to all α‐, β‐, and γ‐CDs and the obtained CD intermediates are versatile. Furthermore, we demonstrate that these processes are practical and can be carried out on multigram scales.