bluuebunny/crossref_metadata_2025_split huggingface dataset:
Curcumin combined with turmerones, essential oil components of turmeric, abolishes inflammation‐associated mouse colon carcinogenesis
Authors: Murakami Akira , Furukawa Ikuyo , Miyamoto Shingo , Tanaka Takuji , Ohigashi Hajime 
Published: December 2012

AbstractCurcumin (CUR), a yellow pigment in turmeric, has marked potential for preventing colon cancer. We recently reported that ar‐turmerone (ATM) suppressed nitric oxide (NO) generation in macrophages. In the present study, we explored the molecular mechanisms by which ATM attenuates NO generation and examined the anti‐carcinogenesis activity of turmerones (TUR, a mixture of 5 sesquiterpenes including ATM). Both CUR and ATM inhibited lipopolysaccharide (LPS)‐induced expression of inducible forms of both nitric oxide synthase and cyclooxygenase (iNOS and COX‐2, respectively). A chase experiment using actinomycin D revealed that ATM accelerated the decay of iNOS and COX‐2 mRNA, suggesting a post‐transcriptional mechanism. ATM prevented LPS‐induced translocation of HuR, an AU‐rich element‐binding protein that determines mRNA stability of certain inflammatory genes. In a colitis model, oral administration of TUR significantly suppressed 2% dextran sulfate sodium (DSS)‐induced shortening of the large bowel by 52–58%. We also evaluated the chemopreventive effects of oral feeding of TUR, CUR, and their combinations using a model of dimethylhydradine‐initiated and DSS‐promoted mouse colon carcinogenesis. At the low dose, TUR markedly suppressed adenoma multiplicity by 73%, while CUR at both doses suppressed adenocarcinoma multiplicity by 63–69%. Interestingly, the combination of CUR and TUR at both low and high doses abolished tumor formation. Collectively, our results led to our hypothesis that TUR is a novel candidate for colon cancer prevention. Furthermore, we consider that its use in combination with CUR may become a powerful method for prevention of inflammation‐associated colon carcinogenesis. © 2012 BioFactors, 2013
Homogenization of Pseudomonas aeruginosa PAO1 biofilms visualized by freeze‐substitution electron microscopy
Authors: Guélon T. , Hunter R.C. , Mathias J.D. , Deffuant G. 
Published: December 2012

AbstractA knowledge of the mechanical properties of bacterial biofilms is required to more fully understand the processes of biofilm formation such as initial adhesion or detachment. The main contribution of this article is to demonstrate the use of homogenization techniques to compute mechanical parameters of Pseudomonas aeruginosa PAO1 biofilms. For this purpose, homogenization techniques are used to analyze freeze substitution electron micrographs of the biofilm cross‐sections. The concept of a representative volume element and the study about his representativeness allows us to determine the optimal size in order to analyze these biofilm images. Results demonstrate significant heterogeneities with respect to stiffness and these can be explained by varying cell density distribution throughout the bacterial biofilms. These stiffness variations lead to different mechanical properties along the height of the biofilm. Moreover, a numerical shear stress test shows the impact of these heterogeneities on the detachment process. Several modes of detachment are highlighted according to the local strain energy in the different parts of the biofilm. Knowing where, and how, a biofilm may detach will allow better prediction of accumulation and biomass detachment. Biotechnol. Bioeng. 2013; 110: 1405–1418. © 2012 Wiley Periodicals, Inc.
Targeting hyperactivation of the AKT survival pathway to overcome therapy resistance of melanoma brain metastases
Authors: Niessner Heike , Forschner Andrea , Klumpp Bernhard , Honegger Jürgen B. , Witte Maria , Bornemann Antje , Dummer Reinhard , Adam Annemarie , Bauer Jürgen , Tabatabai Ghazaleh , Flaherty Keith , Sinnberg Tobias , Beck Daniela , Leiter Ulrike , Mauch Cornelia , Roesch Alexander , Weide Benjamin , Eigentler Thomas , Schadendorf Dirk , Garbe Claus , Kulms Dagmar , Quintanilla‐Martinez Leticia , Meier Friedegund 
Published: December 2012

AbstractBrain metastases are the most common cause of death in patients with metastatic melanoma, and the RAF‐MEK‐ERK and PI3K‐AKT signaling pathways are key players in melanoma progression and drug resistance. The BRAF inhibitor vemurafenib significantly improved overall survival. However, brain metastases still limit the effectiveness of this therapy. In a series of patients, we observed that treatment with vemurafenib resulted in substantial regression of extracerebral metastases, but brain metastases developed. This study aimed to identify factors that contribute to treatment resistance in brain metastases. Matched brain and extracerebral metastases from melanoma patients had identical ERK, p‐ERK, and AKT immunohistochemistry staining patterns, but there was hyperactivation of AKT (p‐AKT) and loss of PTEN expression in the brain metastases. Mutation analysis revealed no differences in BRAF, NRAS, or KIT mutation status in matched brain and extracerebral metastases. In contrast, AKT, p‐AKT, and PTEN expression was identical in monolayer cultures derived from melanoma brain and extracerebral metastases. Furthermore, melanoma cells stimulated by astrocyte‐conditioned medium showed higher AKT activation and invasiveness than melanoma cells stimulated by fibroblast‐conditioned medium. Inhibition of PI3K‐AKT signaling resensitized melanoma cells isolated from a vemurafenib‐resistant brain metastasis to vemurafenib. Brain‐derived factors appear to induce hyperactivation of the AKT survival pathway and to promote the survival and drug resistance of melanoma cells in the brain. Thus, inhibition of PI3K‐AKT signaling shows potential for enhancing and/or prolonging the antitumor effect of BRAF inhibitors or other anticancer agents in melanoma brain metastases.
Heterotypic Sam–Sam Association between Odin‐Sam1 and Arap3‐Sam: Binding Affinity and Structural Insights
Authors: Mercurio Flavia A. , Marasco Daniela , Pirone Luciano , Scognamiglio Pasqualina L. , Pedone Emilia M. , Pellecchia Maurizio , Leone Marilisa 
Published: December 2012

AbstractArap3 is a phosphatidylinositol 3 kinase effector protein that plays a role as GTPase activator (GAP) for Arf6 and RhoA. Arap3 contains a sterile alpha motif (Sam) domain that has high sequence homology with the Sam domain of the EphA2‐receptor (EphA2‐Sam). Both Arap3‐Sam and EphA2‐Sam are able to associate with the Sam domain of the lipid phosphatase Ship2 (Ship2‐Sam). Recently, we reported a novel interaction between the first Sam domain of Odin (Odin‐Sam1), a protein belonging to the ANKS (ANKyrin repeat and Sam domain containing) family, and EphA2‐Sam. In our latest work, we applied NMR spectroscopy, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) to characterize the association between Arap3‐Sam and Odin‐Sam1. We show that these two Sam domains interact with low micromolar affinity. Moreover, by means of molecular docking techniques, supported by NMR data, we demonstrate that Odin‐Sam1 and Arap3‐Sam might bind with a topology that is common to several Sam‐Sam complexes. The revealed structural details form the basis for the design of potential peptide antagonists that could be used as chemical tools to investigate functional aspects related to heterotypic Arap3‐Sam associations.
Gas‐Phase Hydrogenolysis of Glycerol Catalyzed by Cu/MOx Catalysts
Authors: Feng Y. , Yin H. , Shen L. , Wang A. , Shen Y. , Jiang T. 
Published: December 2012

AbstractThe catalytic activities of Cu/MOx (MOx = Al2O3, TiO2, and ZnO) catalysts in the gas‐phase hydrogenolysis of glycerol were studied at 180–300 °C under 0.1 MPa of H2. Cu/MOx (MOx = Al2O3, TiO2, and ZnO) catalysts were prepared by the incipient wetness impregnation method. After reduction, CuO species were converted to metallic copper (Cu0). Cu/Al2O3 catalysts with high acidity, high specific surface areas and small metallic copper size favored the formation of 1,2‐propanediol with a maximum selectivity of 87.9 % at complete conversion of glycerol and a low reaction temperature of 180 °C, and favored the formation of ethylene glycol and monohydric alcohols at high reaction temperature of 300 °C. Cu/TiO2 and Cu/ZnO catalysts exhibited high catalytic activity toward the formation of hydroxyacetone with a selectivity of approx. 90 % in a wide range of reaction temperature.
Game Changers of the C3 Value Chain: Gas, Coal, and Biotechnologies
Authors: Ding J. , Hua W. 
Published: December 2012

AbstractWhile ethylene crackers in Middle East and North America are shifting to ethane feedstocks and the volume of propylene production is becoming less, the market share of on‐purpose propylene production technologies keeps on increasing. In Northeast Asia, due to the shortage of naphtha and natural gas, methanol‐to‐olefin and methanol‐to‐propylene technologies attract much attention. In addition, biochemical technologies are impinging the propylene downstream. Using starch, sugar, or biomass as raw materials, important industrial chemicals such as acrylic acid, butanol, and 1,3‐propanediol can be produced. Propylene glycol and epichlorohydrine can be manufactured using glycerine, the byproduct of biodiesel. All these factors are changing the traditional C3 value chain profoundly. The status of the game‐changing technologies related to the C3 value chain is presented. The relevant factors and the implications will be discussed.
One‐Dimensional Pseudo‐Homogeneous Packed‐Bed Reactor Modeling: I. Chemical Species Equation and Effective Diffusivity
Authors: Srinivasan A. , Depcik C. 
Published: December 2012

AbstractPacked‐bed reactor experimentation is a key tool used in order to formulate chemical kinetics. The chemical species equation and overall methodology are described for a one‐dimensional pseudo‐homogeneous packed‐bed reactor model useful for experimental calibration of chemical kinetics. Over the history of simulation development for this equation there exist numerous different effective diffusivity correlations. The included historical review and parametric study of these correlations help to determine the correct choice based on numerical simplicity and model outcomes. A subsequent review paper describes the energy equation and effective thermal conductivity correlations while coming to a generalized conclusion regarding modeling efforts.
Theoretical Investigation of Macrodipoles in Supramolecular Columnar Stackings
Authors: Albuquerque Rodrigo Q. , Timme Andreas , Kress Roman , Senker Jürgen , Schmidt Hans‐Werner 
Published: December 2012

AbstractSupramolecular columnar assemblies are known to form intrinsic macrodipoles, which play an important role in intercolumnar interactions and govern the self‐assembly on the mesoscale. A prominent class that provides this feature are trisamide derivatives, namely, 1,3,5‐benzenetrisamides and 1,3,5‐cyclohexanetrisamides. The understanding of how subtle changes in the chemical structure influence the columnar order and consequently the macrodipole formation is of fundamental interest. Here we report on the theoretical investigation of trisamide derivatives and how the formed macrodipole is related to the properties of the columnar aggregates. Calculations were carried out on a semiempirical level using the PM6 approximation, which is able to treat weak interactions like hydrogen bonding and dispersion forces with a sufficient accuracy. We have compared the influence of a benzene core with a cyclohexane core on the macrodipole formation. It was revealed that columnar aggregates based on 1,3,5‐cyclohexanetrisamides have much higher dipole moments than those formed with aromatic cores. A cooperative effect was found during aggregation, as longer aggregates show stronger hydrogen bonding, thereby facilitating the addition of the next molecule. We have also investigated the influence of the amide connection on the strength of the formed macrodipole. The trends observed for the macrodipole strength correlate with the calculated heat of formation. If the amide groups are inverted, the strength of the macrodipole is reduced and the negative heat of formation is increased. HOMO–LUMO gaps were correlated with the inverse of the dipole moment per monomer unit, thus indicating that the macrodipole might act as a perturbation to the supramolecular assemblies.
Surface Wrinkling Induced by Photofluidization of Low Molecular Azo Glasses
Authors: Gruner Philipp , Arlt Michael , Fuhrmann‐Lieker Thomas 
Published: December 2012

AbstractPhotoinduced surface wrinkling is demonstrated for a low molecular azo compound confined between a substrate and a thin inorganic elastic layer. The wrinkling process is investigated by time‐resolved light scattering as well as by two‐dimensional autocorrelation analysis of microscopic images. It is shown that the temporal evolution of the wrinkling pattern is directly controlled by the amount of photons absorbed by the sample and that there is no significant dependence of the equilibrium wavelength on irradiation intensity. Finally, the comparison of thermal and photoinduced wrinkling revealed that photoinduced wrinkles are characterized by a narrower mode distribution and less coarsening.
Threshold Collision‐Induced Dissociation of Hydrated Magnesium: Experimental and Theoretical Investigation of the Binding Energies for Mg2+(H2O)x Complexes (x=2–10)
Authors: Carl Damon R. , Armentrout Peter B. 
Published: December 2012

AbstractThe sequential bond energies of Mg2+(H2O)x complexes, in which x=2–10, are measured by threshold collision‐induced dissociation in a guided ion beam tandem mass spectrometer. From an electrospray ionization source that produces an initial distribution of Mg2+(H2O)x complexes in which x=7–10, complexes down to x=3 are formed by using an in‐source fragmentation technique. Complexes smaller than Mg2+(H2O)3 cannot be formed in this source because charge separation into MgOH+(H2O) and H3O+ is a lower‐energy pathway than simple water loss from Mg2+(H2O)3. The kinetic energy dependent cross sections for dissociation of Mg2+(H2O)x complexes, in which x=3–10, are examined over a wide energy range to monitor all dissociation products and are modeled to obtain 0 and 298 K binding energies. Analysis of both primary and secondary water molecule losses from each sized complex provides thermochemistry for the sequential hydration energies of Mg2+ for x=2–10 and the first experimental values for x=2–4. Additionally, the thermodynamic onsets leading to the charge‐separation products from Mg2+(H2O)3 and Mg2+(H2O)4 are determined for the first time. Our experimental results for x=3–7 agree well with quantum chemical calculations performed here and previously calculated binding enthalpies, as well as previous measurements for x=6. The present values for x=7–10 are slightly lower than previous experimental results and theory, but within experimental uncertainties.
Molecular Catalytic Assemblies for Electrodriven Water Splitting
Authors: Joya Khurram Saleem , Vallés‐Pardo Jose L. , Joya Yasir F. , Eisenmayer Thomas , Thomas Brijith , Buda Francesco , de Groot Huub J. M. 
Published: December 2012

AbstractClean energy carriers obtained from renewable, earth‐abundant materials and by using the virtually unlimited supply of sunlight have potential to serve as future sustainable power sources. A quest for new materials for oxygen evolution from catalytic water oxidation and carbon dioxide reduction, which aim to build up solar‐to‐fuel conversion devices that use water as raw material, has been developing during the last two decades. Most of the research in the field of materials science and chemistry has been focused on the development of inorganic materials and molecular complexes for water oxidation, in particular bioinspired catalytic systems. Recently, various molecular water‐oxidation complexes with mono‐ or multinuclear catalytic sites have been tested for solution‐phase dioxygen generation. Catalyst immobilization and functionalization on an electrode surface is required for electrocatalytic or photoelectrochemical water oxidation devices; however, there are only a few examples in which a molecular catalyst has been placed on a transparent conducting surface in an electro‐ or photoelectrochemical system. Herein, a brief overview of surface‐immobilized molecular assemblies for electrochemical water oxidation is presented, and an analysis of recent progress in catalyst design and performance is provided, including systems integration of modules for future stand‐alone solar‐to‐fuel conversion devices. A view on the thermodynamics features of various intermediates and the mechanism of OO bond formation in single‐site complexes and binuclear water oxidation catalysts is also presented.
Direct Selective Hydrogenation of Phenol and Derivatives over Polyaniline‐Functionalized Carbon‐Nanotube‐Supported Palladium
Authors: Chen Jinzhu , Zhang Wei , Chen Limin , Ma Longlong , Gao Hui , Wang Tiejun 
Published: December 2012

AbstractCyclohexanone is an industrially important intermediate in the synthesis of materials such as nylon and polyamides, but direct selective hydrogenation of phenol to cyclohexanone under green conditions is a challenge owing to the over‐reduction of cyclohexanone to cyclohexanol. A catalyst made of palladium nanoparticles supported on polyaniline‐functionalized carbon nanotubes, Pd–PANI/CNT, which was shown to be highly active towards the direct hydrogenation of phenol to cyclohexanone, is reported. Phenol conversion exceeding 99 % was achieved with a cyclohexanone selectivity of >99 % under atmospheric pressure of hydrogen in aqueous media. The generality of the catalyst for this reaction was demonstrated by selective hydrogenation of other hydroxylated aromatic compounds with similar performance, again under green and mild conditions. It is suggested the Pd–N interactions and polymeric stabilization play a key role in the formation of stable and highly dispersed palladium nanoparticles on the conducting composite material PANI/CNT. The results also indicate that the phenol conversion is related presumably to the conductive property of PANI/CNT, whereas the cyclohexanone selectivity is attributed to the nitrogen‐containing nature of PANI/CNT.
Charakterisierung und Modellierung der mechanischen Eigenschaften von Lehmsteinmauerwerk – Mechanical Characterization and Modelling of Earth Block Masonry
Authors: Miccoli Lorenzo , Fontana Patrick , Ziegert Christof , Perrone Chiara , Müller Urs 
Published: December 2012

AbstractDas Wissen über die Materialeigenschaften und die Versagensmechanismen bei Lehmbaustoffen ist begrenzt und lückenhaft. Im Rahmen des EU‐Projekts NIKER (www.niker.eu) wurden deshalb die mechanischen Eigenschaften von Bauteilen aus Lehm unter statischer Druck‐ und Schubbeanspruchung bestimmt. Ziel der Untersuchungen war es, grundlegende Daten zum Verformungs‐ und Versagensverhalten von Lehmbauteilen zu erhalten und dieses mit einem numerischen Modell zu beschreiben. Die Versuchsergebnisse belegten das spröde Verhalten von Lehmsteinmauerwerk bei uniaxialer Druckbelastung und zeigten, dass das Versagen von Lehmsteinmauerwerk infolge Schubbelastung nach Erstrissbildung in Mörtelfugen und Lehmsteinen durch Gleiten der Lehmsteine entlang der Mörtelfugen erfolgt. Die numerische Makromodellierung erbrachte zwar befriedigende Resultate hinsichtlich des Spannungs‐Dehnungs‐Verhaltens, jedoch konnte bei der simulierten Rissbildung keine Übereinstimmung mit den in den Versuchen beobachteten Rissbildern erzielt werden. Bei Lehmsteinmauerwerk ist also eine wesentlich aufwendigere Mikromodellierung notwendig, um das Versagensverhalten korrekt beschreiben zu können.Knowledge of the material properties and failure mechanisms of earthen materials is limited and scattered. Within the framework of the NIKER project (www.niker.eu) funded by EC, the mechanical properties of earthen material elements were therefore determined under static compression and shear loads. The aim was to obtain fundamental data on deformation behaviour and failure mechanisms of earthen material structural elements and to describe them by means of a numerical model. The test results confirmed the brittle behaviour of earth block masonry under monoaxial compressive load and showed that the failure of earth block masonry under shear load occurs by sliding of the earth blocks along the mortar joints after initial cracking in mortar joints and earth block. Numerical macro modelling showed satisfying results with regard to stress‐strain behaviour, but the simulated crack pattern was not consistent with experimental observations. In the case of earth block masonry, it is thus necessary to use micro modelling approaches in order to correctly predict the failure process at local level.
Antioxidant activity of yerba mate extracts: Interactions between the individual polyphenols
Authors: Valerga Julia , Shorthose Robin , Lanari Maria C. 
Published: December 2012

AbstractYerba mate extracts contain strong antioxidants like chlorogenic (CL) and its derivatives, caffeic (C), quercetin (Q), rutin (R), and kaempferol (K) that may improve food products nutritional quality and rancidity. To obtain products with consistent activity and composition, we analyzed the effect of yerba's industrial processing on extracts composition, radical scavenging capacity (AA), inhibition of β‐carotene/linoleic acid oxidation (AI), and ferric reducing/antioxidant power (RP). We also determined the relationship between the composition of a mixture of C, CL, K, Q, and R and their AA, RP, and AI values. Industrial processing modified polyphenol composition and antioxidant activity of the yerba extracts. Pre‐dried and dried/canchada leaves were the most appropriate raw materials combining optimum AA, RP, and AI levels. Extract's capacity to improve ground beef's lipid stability was better than similar levels of α‐tocopherol. Relationships between AA, RP, or AI and polyphenol composition were satisfactorily predicted by a quadratic, a full or a reduced cubic models, respectively. Simultaneous optimization of all models allowed determining the best and worst performing blends. Extracts contents of caffeic, chlorogenic and its derivatives, quercetin, and rutin were within or under the limits of the least active region predicted and may account for the low activity levels observed.Practical applications: Due to its antioxidant and therapeutic properties; polyphenolic extracts from yerba mate leaves can improve the sensorial quality and shelf life of ground beef and sunflower oil as well as enhance the organism defense system. Commercial application of these extracts by the food and pharmaceutical industry requires products of consistent composition and activity. In this study we also determined the best raw material across the different processing steps and developed mathematical models that can be used to calculate the antioxidant activity of yerba extracts based on their polyphenol composition.
Stepwise catalytic transformations of renewable feedstock arising from plant oils
Authors: Dupé Antoine , Le Ravalec Virginie , Fischmeister Cédric , Bruneau Christian 
Published: December 2012

AbstractTwo synthetic approaches to produce functionalized plant oil derivatives were investigated. The ruthenium‐catalyzed ene‐yne cross‐metathesis of propargylic carbonates with terminal olefins arising from ethenolysis of methyl oleate provides conjugated dienes. It was shown that the reactivity of these dienes in Diels–Alder [4 + 2]‐cycloaddition with symmetrical electron‐deficient alkynes towards the formation of cyclohexadienes was effective but limited by stereochemical considerations. On the other hand, the stepwise ene‐yne cross‐metathesis followed by ruthenium‐catalyzed nucleophilic allylic substitution by O, N, and C‐nucleophiles was very efficient both in term of reactivity and regioselectivity.