bluuebunny/crossref_metadata_2025_split huggingface dataset:
The rheology and extrusion processing performance of wood/melamine composites
Authors: Englund Karl , Chen Lee‐Wen 
Published: September 2013

ABSTRACTA modified melamine resin that exhibits both thermoplastic and thermoset behaviors was used as a matrix for wood plastic composites (WPCs). The thermoplastic melamine (TPM) resin exhibits a glass transition at approximately 34°C and continues to be thermally malleable until a crosslinking reaction develops with additional heating and an acid catalyst. Varying blends of TPM and wood flour were evaluated for their rheology and curing behavior using torque rheometry. WPC composites were manufactured with extrusion methods and final product properties determined. The torque rheometry results showed a highly dependent relationship of the curing behavior to the amount of wood flour utilized and temperature. Based upon the torque rheometry results, two extrusion platforms were developed to initiate the curing process; (1) cure within the die land and (2) post‐cure of the extrudate. The post‐cure procedure provided composites with higher mechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39858.
Waste ground rubber tire powder/thermoplastic vulcanizate blends: Preparation, characterization, and compatibility
Authors: Lu Xun , Wang Weiwei , Yu Lin 
Published: September 2013

ABSTRACTIn this article, waste ground rubber tire (WGRT) powder was introduced into thermoplastic vulcanizate (TPV) to prepare the blends of WGRT powder/TPV. The mechanical, rheological, thermal aging, and dynamic properties of the blends were investigated with respect to the particle size and dosage of WGRT powder. The results showed that tensile strength, tear strength, elongation at break, and tensile permanent deformation of the blends increased with the decrease in WGRT particle size and decreased with the dosage of WGRT. The effects of different types and dosages of compatibilizers on mechanical and rheological properties of the blends were studied. The results showed that the compatibilizer PP‐g‐MAH could effectively improve the interfacial compatibility between WGRT and the TPV matrix to enhance the comprehensive properties of blends. The TPV/WGRT/PP‐g‐MAH blends obtained the best overall properties when prepared at the weight ratio 100/30/5. Rheological studies demonstrated that the WGRT/TPV blends represented lower apparent viscosity after PP‐g‐MAH were added, which means that processing performance of the blends was improved by PP‐g‐MAH. Scanning electron microscopy was used to study the morphologies of the blends. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39868.
Repetitive Arg‐Gly‐Asp peptide as a cell‐stimulating agent on electrospun poly(ϵ‐caprolactone) scaffold for tissue engineering
Authors: Chaisri Pacharaporn , Chingsungnoen Artit , Siri Sineenat 
Published: September 2013

AbstractElectrospun scaffolds derived from poly(ϵ‐caprolactone) (PCL), a well known biodegradable material, have an architecture that is suitable for hosting cells. However, their biomedical applications are restricted because these scaffolds lack the bioactivity necessary to stimulate cell responses. In this work, a repetitive Arg‐Gly‐Asp (rRGD) peptide was produced as a cell‐stimulating agent to provide the PCL scaffold with bioactivity. DNA encoding rRGD was amplified by polymerase chain reaction using overlap primers without a DNA template, and cloned into a protein expression vector to produce a His‐tag fusion peptide. In an in vitro cell adhesion assay, the purified rRGD peptide, comprising 30 RGD repeats, promoted a 1.5‐fold greater cell adhesion than the commercial tripeptide RGD. The rRGD peptide was immobilized onto an electrospun PCL scaffold that had been pretreated with argon plasma and graft‐polymerized with acrylic acid. Fourier transform infrared (FTIR) analysis indicated that covalently linked rRGD peptide was present on the scaffold. The PCL scaffold with immobilized rRGD showed significantly changed hydrophilic properties and an enhanced adhesion and proliferation of mouse fibroblast cells by 2.3‐ and 2.9‐fold, respectively, compared to the PCL scaffold alone. Through its ability to promote cell adhesion and proliferation, the rRGD peptide has great potential as a stimulant for improving the suboptimal cell‐matrix interaction of polymeric scaffolds for tissue engineering applications.
Tuning the Catalytic Selectivity of Copper Using TiO2: Water‐Gas Shift versus CO Oxidation
Authors: Kim Hyun You , Liu Ping 
Published: September 2013

AbstractAs an early attempt to tune the selectivity of Cu catalysts through oxide deposition, we performed DFT calculations to study the water‐gas shift (WGS) and CO oxidation reactions at the interface of Cu(1 1 1) modified by TiO2 clusters [TiO2/Cu(1 1 1)]. Pure Cu catalyzes both reactions, though the overall conversion is hindered by either H2O dissociation or O2 dissociation. Our results show that after depositing TiO2, TiO2/Cu(1 1 1) promotes the CO oxidation reaction and suppresses the WGS reaction. The active Ti3fCu site at the TiO2/Cu(1 1 1) interface plays an essential role in tuning the selectivity. During the CO oxidation reaction, the Ti3fCu site enables the facile O2 dissociation at the interface, which leads to the oxidation of the surface layer on Cu(1 1 1) and the formation of Cu2O. According to our calculations, the produced TiO2/Cu2O(1 1 1) interface is active toward CO oxidation, which not only binds O2 and CO well but also enables a facile OO bond cleavage via the OOCO intermediate. During the WGS reaction, the Ti3fCu site is poisoned by CO and the rate‐limiting H2O dissociation and therefore the overall WGS is hindered. The results suggest that high selectivity, one of the focuses for next generation catalysts, can be achieved by modifying the chemical properties of the interface.
Water as an Activator for Palladium(II)‐Catalyzed Olefin Polymerization
Authors: Tao Wen‐Jie , Li Jun‐Fang , Peng Ai‐Qing , Sun Xiu‐Li , Yang Xiao‐Hong , Tang Yong 
Published: September 2013

AbstractBy a reasonable combination of the Wacker reaction and olefin polymerization processes, water proves to be an excellent activator for the palladium(II)‐catalyzed polymerization of ethylene and it provides a safe, environmental‐friendly and handy initiator for olefin polymerization. The activity of the olefin polymerization is comparable to reactions catalyzed by the corresponding alkylated cationic palladium complexes.
Aminopyridinate–FI Hybrids, Their Hafnium and Titanium Complexes, and Their Application in the Living Polymerization of 1‐Hexene
Authors: Haas Isabelle , Dietel Thomas , Press Konstantin , Kol Moshe , Kempe Rhett 
Published: September 2013

AbstractBased on two well‐established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap‐FI hybrid ligands were developed. Four different Ap‐FI hybrid ligands were synthesized through a simple condensation reaction and fully characterized. The reaction of hafnium tetrabenzyl with all four Ap‐FI hybrid ligands exclusively led to mono(Ap‐FI) complexes of the type [(Ap‐FI)HfBn2]. The ligands acted as tetradentate dianionic chelates. Upon activation with tris(pentafluorophenyl)borane, the hafnium‐dibenzyl complexes led to highly active catalysts for the polymerization of 1‐hexene. Ultrahigh molecular weights and extremely narrow polydispersities support the living nature of this polymerization process. A possible deactivation product of the hafnium catalysts was characterized by single‐crystal X‐ray analysis and is discussed. The coordination modes of these new ligands were studied with the help of model titanium complexes. The reaction of titanium(IV) isopropoxide with ligand 1 led to a mono(Ap‐FI) complex, which showed the desired fac‐mer coordination mode. Titanium (IV) isopropoxide reacted with ligand 4 to give a complex of the type [(ApH‐FI)2Ti(OiPr)2], which featured the ligand in its monoanionic form. The two titanium complexes were characterized by X‐ray crystal‐structure analysis.
Insights into the Reactivity of Gold–Dithiocarbamato Anticancer Agents toward Model Biomolecules by Using Multinuclear NMR Spectroscopy
Authors: Boscutti Giulia , Marchiò Luciano , Ronconi Luca , Fregona Dolores 
Published: September 2013

AbstractSome gold(III)–dithiocarbamato derivatives of either single amino acids or oligopeptides have shown promise as potential anticancer agents, but their capability to interact with biologically relevant macromolecules is still poorly understood. We investigated the affinity of the representative complex [AuIIIBr2(dtc‐Sar‐OCH3)] (dtc: dithiocarbamate; Sar: sarcosine (N‐methylglycine)) with selected model molecules for histidine‐, methionine‐, and cysteine‐rich proteins (that is, 1‐methylimidazole, dimethylsulfide, and N‐acetyl‐L‐cysteine, respectively). In particular, detailed mono‐ and multinuclear NMR studies, in combination with multiple 13C/15N enrichments, allowed interactions to be followed over time and indicated somewhat unexpected reaction pathways. Whereas dimethylsulfide proved to be unreactive, a sudden multistep redox reaction occurred in the presence of the other potential sulfur donor, N‐acetyl‐L‐cysteine (confirmed if glutathione was used instead). On the other hand, 1‐methylimidazole underwent an unprecedented acid–base reaction with the gold(III) complex, rather than the expected coordination to the metal center by replacing, for instance, a bromide. Our results are discussed herein and compared with the data available in the literature on related complexes; our findings confirm that the peculiar reactivity of gold(III)–dithiocarbamato complexes can lead to novel reaction pathways and, therefore, to new cytotoxic mechanisms in cancer cells.
Manganese‐Induced Triplet Blinking and Photobleaching of Single Molecule Cyanine Dyes
Authors: Ciuba Monika A. , Levitus Marcia 
Published: September 2013

AbstractIrradiation of solutions of the cyanine dyes Cy3, Cy3B, and Cy5 in the presence of Mn2+ causes an increase in the yield of formation of the triplet state of the dye. This results in increased photobleaching and triplet blinking. Experiments with other divalent ions and paramagnetic molecules suggest that the enhancement in the intersystem‐crossing rate is related to the paramagnetic nature of the Mn2+ cation. The results are consistent with a model in which the formation of a weak collisional complex between the dye and the ion results in mixing of the singlet and triplet states of the dye. These findings are particularly significant in single‐molecule spectroscopy and super‐resolution imaging methods, in which photobleaching and blinking play an important role.
Comparison and evaluation of seven different bench‐top flow cytometers with a modified six‐plexed mycotoxin kit
Authors: Czeh Arpad , Schwartz Abe , Mandy Frank , Szoke Zsuzsanna , Koszegi Balazs , Feher‐Toth Szilvia , Nagyeri Gyorgy , Jakso Pal , Katona Robert L. , Kemeny Agnes , Woth Gabor , Lustyik Gyorgy 
Published: September 2013

AbstractMany bench‐top flow cytometers (b‐FCs) are compatible with microsphere‐based multiplexed assays. Disciplines implementing b‐FCs–based assays are expanding; they include monitoring and validating food quality. A multiplexed platform protocol was evaluated for poly‐mycotoxin assays, which is compatible with a variety of b‐FC models. The seven instruments included: BD FACSCalibur™, BD FACSArray™ Bioanalyzer, Accuri C6, Partec CyFlow® Space, Beckman Coulter FC 500, Guava EasyCyte Mini, and Luminex 100 ™. Current reports related to the food industry describe fungal co‐infections leading to poly‐mycotoxin contamination in grain (Sulyok M, Berthiller F, Krska R, Schuhmacher R, Rapid Commun Mass Spectrom 2006;20:2649–2659). It is imperative to determine whether b‐FC–based assays can replace traditional single‐mycotoxin enzyme‐linked immunosorbent assay (ELISA). A six‐plexed poly‐mycotoxin kit was tested on seven different b‐FCs. The modified kit was initially developed for the BD FACSArray™ Bioanalyzer (BD Biosciences) (Czeh A, Mandy F, Feher‐Toth S, Torok L, Mike Z, Koszegi B, Lustyik G, J Immunol Methods 2012;384:71–80). With the multiplexed platform, it is possible to identify up to six mycotoxin contaminants simultaneously at regional grain collection/transfer/inspection facilities. In the future, elimination of contaminated food threat may be better achieved with the inclusion of b‐FCs in the food protection arsenal. A universal protocol, matched with postacquisition software, offers an effective alternative platform compared to using a series of ELISA kits. To support side‐by‐side evaluation of seven flow cytometers, an instrument‐independent fluorescence emission calibration was added to the protocol. All instrument performances were evaluated for strength of agreement based on paired sets of evaluation to predicate method. The results suggest that all b‐FCs were acceptable of performing with the multiplexed kit for five of six mycotoxins. For OTA, the detection sensitivity was consistent only for five of the seven instruments. © 2013 International Society for Advancement of Cytometry
Anwendung des Eurocode 6 in der Tragwerksplanung
Authors: Purtak Frank 
Published: September 2013

AbstractDer Nachweis der Tragfähigkeit von Mauerwerk wird am Beispiel einer Außen‐ und Innenwand auf Grundlage der Schnittgrößenermittlung mit den “Vereinfachten“ und “Genaueren“ Bemessungsverfahren durchgeführt. Der Schubnachweis wird exemplarisch an einer Aussteifungswand mit den möglichen vier Versagenskriterien aufgezeigt.Sollten die Anwendungsgrenzen der “Vereinfachten Verfahren“ bei bestimmten Bauvorhaben nicht eingehalten sein, liefern die hiermit ermittelten Ausnutzungsgrade die maßgebenden Wände, welche mit dem “Genaueren Verfahren“ nachzuweisen sind.Application of the Eurocode 6 in the structural design. The proof of load bearing capacity of brick work is shown using the example of an exterior and an interior wall on the basis of the assessment of the state of strain with the “simplified” and with the “more precise” design procedure. The shear check is shown exemplarily on a bracing wall with the four failure criteria.In case that certain building projects don’t comply with the limitations of the “simplified procedure”, the degree of utilization determined hereby shows the proper walls which have to be proven with the “more precise” design procedure.
Copper(I)‐Catalyzed Highly Regio‐ and Stereoselective Boron Addition–Protonolysis of Alkynamides to give Alkenamides
Authors: He Guangke , Zhang Qijun , Huang Hai , Chen Shan , Wang Qiang , Zhang Dongming , Zhang Rong , Zhu Hongjun 
Published: September 2013

AbstractCopper‐catalyzed and highly chemoselective reduction of N‐alkynylamides by a boron addition–protonolysis protocol is presented. The reaction proceeds with the addition of boryl‐copper complex to N‐alkynylamides with high regioselectivity and stereoselectivity, followed by regiocontrolled transmetallation of the α‐site of the alkenylboronate with MeOCuL to afford N‐alkenylamides in good yields. Deuterium labeling experiments indicated that both of the alkenyl hydrogen atoms originate from the additive methanol.
Synthesis of Versatile Nonsymmetric Amine‐ and Boron‐Functionalized Tröger's Base Derivatives, Including a Tröger's Base Amino Acid
Authors: Whiting Amanda L. , Dubicki Krystyn I. , Hof Fraser 
Published: September 2013

AbstractTröger's base is a building block with a unique rigidity and geometry that has an increasing number of applications in a variety of nanoscale chemistry projects. This paper describes the facile synthesis of a set of Tröger's base derivatives that have lost their C2 symmetry by virtue of having each ring differentiated, and contain amine, carboxylate, halogen, and/or boronate substituents to enable a large number of different cross‐coupling and amide coupling reactions. We also describe the synthesis and preliminary chiral resolution of a new Tröger's base amino acid building block.
Characteristics of Alkali and Alkaline‐Earth Metals for the Catalytic Gasification of Coal Char in a Fixed‐Bed Reactor
Authors: Wang Yifei , Jin Weilong , Huang Taohua , Zhu Longchu , Wu Chaoqi , Yu Guangsuo 
Published: September 2013

AbstractThe effects of temperature, catalyst type, and catalyst loading on the gasification of coal char were investigated in a fixed‐bed reactor. The effects of catalyst dispersion, Brunauer–Emmett–Teller (BET) specific surface area, and crystallite constituents of Jinyou coal char with different loadings of K and Ca were also analyzed by energy‐dispersive X‐ray analysis (EDX), N2adsorption at 77 K, and X‐ray diffraction (XRD). Results showed that K2CO3could increase the gasification rate significantly for gasification temperatures greater than 850 °C. Cation species could have a significant influence on the catalytic activity. The reactivity of the coal char increased continuously with catalyst loading and resulted in a loading saturation level (LSL) of 10 % for K. Compared with the raw char, K and Ca added to Jinyou coal decreased the BET specific surface area. Moreover, K and Ca added to Jinyou coal altered the crystallite constituents during the process of coking and gasification, which indicated that some K and Ca reacted with minerals in the Jinyou coal during the process of coking and gasification and partly deactivated the K and Ca.
Bioaccumulation kinetics of polybrominated diphenyl ethers and decabromodiphenyl ethane from field-collected sediment in the oligochaete, Lumbriculus variegatus
Authors: Zhang Baozhong , Li Huizhen , Wei Yanli , You Jing 
Published: September 2013

Abstract

The extensive use of polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) has made them widespread contaminants in abiotic environments, but data regarding their bioavailability to benthic organisms are sparse. The bioaccumulation potential of PBDEs and DBDPE from field-collected sediment was evaluated in the oligochaete Lumbriculus variegatus using a 49-d exposure, including a 28-d uptake and a 21-d elimination phase. All PBDEs and DBDPE were bioavailable to the worms with biota–sediment accumulation factors (BSAFs) ranging from 0.0210 g organic carbon/g lipid to 4.09 g organic carbon/g lipid. However, the bioavailability of highly brominated compounds (BDE-209 and DBDPE) was poor compared with that of other PBDEs, and this was confirmed by their relatively low freely dissolved concentrations (Cfree) measured by solid-phase microextraction. The inverse correlation between BSAFs and hydrophobicity was explained by their uptake (ks) and elimination (ke) rate constants. While ke changed little for PBDEs, ks decreased significantly when chemical hydrophobicity increased. The difference in bioaccumulation kinetics of brominated flame retardants in fish and the worms was explained by their physiological difference and the presence of multiple elimination routes. The appropriateness of 28-d bioaccumulation testing for BSAF estimation was validated for PBDEs and DBDPE. In addition, Cfree was shown to be a good indicator of bioavailability. Environ Toxicol Chem 2013;32:2711–2718. © 2013 SETAC
Amelioration of acidic soil increases the toxicity of the weak base carbendazim to the earthworm Eisenia fetida
Authors: Liu Kailin , Wang Shaoyun , Luo Kun , Liu Xiangying , Yu Yunlong 
Published: September 2013

Abstract

Ameliorating acidic soils is a common practice and may affect the bioavailability of an ionizable organic pollutant to organisms. The toxicity of the weak base carbendazim to the earthworm (Eisenia fetida) was studied in an acidic soil (pH–H2O, 4.6) and in the ameliorated soil (pH–H2O, 7.5). The results indicated that the median lethal concentration of carbendazim for E. fetida decreased from 21.8 mg/kg in acidic soil to 7.35 mg/kg in the ameliorated soil. To understand why the amelioration increased carbendazim toxicity to the earthworm, the authors measured the carbendazim concentrations in the soil porewater. The authors found increased carbendazim concentrations in porewater, resulting in increased toxicity of carbendazim to earthworms. The increased pore concentrations result from decreased adsorption because of the effects of pH and calcium ions. Environ Toxicol Chem 2013;32:2870–2873. © 2013 SETAC
Brain network alterations in Alzheimer's disease measured by Eigenvector centrality in fMRI are related to cognition and CSF biomarkers
Authors: Binnewijzend Maja A.A. , Adriaanse Sofie M. , Van der Flier Wiesje M. , Teunissen Charlotte E. , de Munck Jan C. , Stam Cornelis J. , Scheltens Philip , van Berckel Bart N.M. , Barkhof Frederik , Wink Alle Meije 
Published: September 2013

AbstractRecent imaging studies have demonstrated functional brain network changes in patients with Alzheimer's disease (AD). Eigenvector centrality (EC) is a graph analytical measure that identifies prominent regions in the brain network hierarchy and detects localized differences between patient populations. This study used voxel‐wise EC mapping (ECM) to analyze individual whole‐brain resting‐state functional magnetic resonance imaging (MRI) scans in 39 AD patients (age 67 ± 8) and 43 healthy controls (age 69 ± 7). Between‐group differences were assessed by a permutation‐based method. Associations of EC with biomarkers for AD pathology in cerebrospinal fluid (CSF) and Mini Mental State Examination (MMSE) scores were assessed using Spearman correlation analysis. Decreased EC was found bilaterally in the occipital cortex in AD patients compared to controls. Regions of increased EC were identified in the anterior cingulate and paracingulate gyrus. Across groups, frontal and occipital EC changes were associated with pathological concentrations of CSF biomarkers and with cognition. In controls, decreased EC values in the occipital regions were related to lower MMSE scores. Our main finding is that ECM, a hypothesis‐free and computationally efficient analysis method of functional MRI (fMRI) data, identifies changes in brain network organization in AD patients that are related to cognition and underlying AD pathology. The relation between AD‐like EC changes and cognitive performance suggests that resting‐state fMRI measured EC is a potential marker of disease severity for AD. Hum Brain Mapp 35:2383–2393, 2014. © 2013 Wiley Periodicals, Inc.