Replication of SMSI via ALD: TiO<Subscript>2</Subscript> Overcoats Increase Pt-Catalyzed Acrolein Hydrogenation Selectivity

The effects of sub-nanometer atomic layer deposition films of titania and alumina are compared for the acrolein hydrogenation selectivity of Pt/SrTiO₃ catalysts. The titania-overcoated catalyst is similar to strong metal-support interaction catalysts formed by high temperature reduction, with a thin titania film on top of the supported Pt nanoparticles and an increase in allyl alcohol selectivity, neither of which are observed for the alumina-overcoated catalyst.

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Molecular characterization of three peroxisome proliferator-activated receptors from the sea bass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>)

Peroxisome proliferator-activated receptors (PPAR) are nuclear hormone receptors that control the expression of genes involved in lipid homeostasis in mammals. We searched for PPAR in sea bass, a marine fish of particular interest to aquaculture, after hypothesizing that the physiological and molecular processes that regulate lipid metabolism in fish are similar to those in mammals. Here, we report the identification of complementary DNA and corresponding genomic sequences that encode three distinct PPAR from sea bass. The sea bass PPAR are the structural homologs of the mammalian PPARα, β/δ and γ isotypes. As revealed by RNase protection, the tissue expression profile of the fish PPAR appears to be very similar to that of the mammalian PPAR homologs. Thus, PPARα is mainly expressed in the liver, PPARγ in adipose tissue, and PPARβ in all tissues tested, with its highest levels in the liver, where it is also the dominant isotype expressed. Like mammalian PPAR, the sea bass isotypes recognize and bind to PPAR response elements of both mammalian and piscine origin, as heterodimers with the 9-cis retinoic acid receptor. Through the coactivator-dependent receptor ligand assay, we also demonstrated that natural FA and synthetic hypolipidemic compounds can act as ligands of the sea bass PPARα and β isotypes. This suggests that the sea bass PPAR act through similar mechanisms and perform the same critical lipid metabolism functions as mammalian PPAR.     

Nonlinear stress relaxation in palladium(II) complexes with triblock copolymers of styrene and butadiene

Above 200% strain, the mechanical response of triblock copolymers which contain styrene and butadiene is modified significantly by complexation with dichlorobis(acetonitrile)palladium(II). This pseudosquare‐planar transition metal salt forms π‐complexes with, and catalyzes the dimerization of, alkene groups in the main chain and the side group of Kraton's butadiene midblock. Between 10 and 100% strain, the plastic flow regime is similar for undiluted Kraton? and its Pd²⁺ complexes, but the level of engineering stress is approximately twofold larger for the complex that contains 4 mol % palladium(II) [Pd(II)]. Nonlinear stress relaxation measurements in the plastic flow regime (i.e., beyond the yield point but before the large upturn in stress) are analyzed at several different levels of strain. Transient relaxation moduli were modeled by a three‐parameter biexponential decay with two viscoelastic time constants. The longer relaxation time for Kraton? increases at higher strain, and in the presence of 4 mol % palladium chloride. A phenomenological model is proposed to describe the effect of strain on relaxation times. This model is consistent with the fact that greater length scales are required for cooperative segmental reorganization at larger strain. The resistance Ω to conformational reorganization during stress relaxation is estimated via integration of the normalized relaxation modulus versus time data. This resistance increases at higher initial jump strain because conformational rearrangements are influenced strongly by knots and entanglements at larger strain. The effect of strain on Ω is analyzed in terms of time‐strain separability of the relaxation modulus. Linear behavior is observed for Ω versus inverse strain (i.e., 1/ε), and the magnitude of the slope [i.e., ?dΩ/d(1/ε)] is threefold larger in the absence of PdCl₂(CH₃CN)₂. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1329–1336, 2004     

Novel wet adhesion monomers for use in latex paints

Coating failure through loss of adhesion is a common occurrence with latex paints especially when applied to previously painted alkyd surfaces. Wet adhesion promoters are used by the industry to overcome these deficiencies. This paper provides an overview of the technical effort at Cytec which has led to the discovery of a series of new wet adhesion monomers. Three such monomers have been under active development. At least one of these is expected to be available in developmental quantities later this year. These monomers are targeted at improving the wet adhesion performance of exterior and interior latex paints which are frequently exposed to moisture due to rain and/or high humidity. They have been incorporated into latex polymers which, when formulated into exterior latex paints, show excellent wet adhesion properties. Wet scrub test results on aged alkyd coated Laneta panels are discussed, along with comparative data on a currently available monomer.     

Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium

The complexation and extraction of the adjacent minor actinides Am(III) and Cm(III) by both hydrophobic and hydrophilic pre-organized 2,9-bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) ligands has been studied in detail. It has been shown that Am(III) is extracted more rapidly than Cm(III) by the hydrophobic CyMe₄–BTPhen ligand into different organic diluents under nonequilibrium extraction conditions, leading to separation factors for Am over Cm (SF_Am/Cm) as high as 7.9. Furthermore, the selectivity for Am(III) over Cm(III) can be tuned through careful choice of the extraction conditions (organic diluent, contact time, mixing speed, ligand concentration). This “kinetic” effect is attributed to the higher presumed kinetic lability of the Am(III) aqua complex toward ligand substitution. A dependence of the Am(III)/Cm(III) selectivity on the structure of the alkyl groups attached to the triazine rings is also observed, and BTPhens bearing linear alkyl groups are less able to discriminate between Am(III) and Cm(III) than CyMe₄–BTPhen. Under equilibrium extraction conditions, hydrophilic tetrasulfonated BTPhen ligands complex selectively Am(III) over Cm(III) and prevent the extraction of Am(III) from nitric acid by the hydrophobic O-donor ligand N,N,N′,N′-tetraoctyldiglycolamide, giving separation factors for Cm(III) over Am(III) (SF_Cm/Am) of up to 4.6. These results further underline the utility of the BTPhen ligands for the challenging separation of the chemically similar minor actinides Am(III) and Cm(III).     

Loop-mediated amplification accelerated by stem primers

Isothermal nucleic acid amplifications (iNAATs) have become an important alternative to PCR for in vitro molecular diagnostics in all fields. Amongst iNAATs Loop-mediated amplification (LAMP) has gained much attention over the last decade because of the simplicity of hardware requirements. LAMP demonstrates performance equivalent to that of PCR, but its application has been limited by the challenging primer design. The design of six primers in LAMP requires a selection of eight priming sites with significant restrictions imposed on their respective positioning and orientation. In order to relieve primer design constraints we propose an alternative approach which uses Stem primers instead of Loop primers and demonstrate the application of STEM-LAMP in assaying for Clostridium difficile, Listeria monocytogenes and HIV. Stem primers used in LAMP in combination with loop-generating and displacement primers gave significant benefits in speed and sensitivity, similar to those offered by Loop primers, while offering additional options of forward and reverse orientations, multiplexing, use in conjunction with Loop primers or even omission of one or two displacement primers, where necessary. Stem primers represent a valuable alternative to Loop primers and an additional tool for IVD assay development by offering more choices for primer design at the same time increasing assay speed, sensitivity, and reproducibility.     

Technological evolution of ceramic glazes in the renaissance: In situ analysis of tiles in the Alcazar (Seville,Spain)

The Alcazar Palace (Seville, Spain) is famous for its ceramic decorations; 16th century wall tiles of different typologies have been analyzed in order to relate the manufacturing process of their colored glazes to the evolving technologies of the Renaissance. Chemical and mineralogical compositions have been determined in situ by nondestructive X-ray fluorescence and X-ray diffraction on arista ceramics in the Cenador de Carlos Quinto, and majolica ceramics in the Palacio Gotico and the Royal oratory. The arista style belongs to the local Hispano-Moresque ceramic tradition. Majolica tiles have the complex microstructures of glazes from Italy. The two types are clearly differentiated by their typology, morphology (curved vs flat surface), and also microstructure (single vs multi-layers), glaze chemistry, and use of different coloring agents. Moreover, we found different glaze chemistries in the investigated majolicas, which correspond to different artists and/or practices.     

Near field inversion method to measure the material properties of a layer

This study develops an in situ methodology that uses ultrasonic waves to measure the material properties of a layer. These material properties include the longitudinal and shear wave speeds, as well as the thickness of the layer. The unknown properties are determined by comparing measured experimental data with values obtained from a theoretical model. Emphasis is placed on the effectiveness of measuring both the in-plane, and the out-of-plane surface displacement components with a laser Doppler vibrometer. An inversion scheme compares (in the frequency domain) the experimentally measured data with data predicted using the theoretical model, and an error-function quantifies the difference between these values. Finally, a downhill-simplex algorithm is used to minimize this error-function and thus determine an optimum set of material properties.     

Factors impacting the formation of monochloropropanediol (MCPD) fatty acid diesters during palm (Elaeis guineensis) oil production

Recently, organic and inorganic chlorinated compounds were detected in crude and commercially refined palm oils. Further, the predominant formation mechanism of monochloropropanediol (MCPD) diesters at high temperatures (>170-180°C) was revealed. The present study involved the development and comparison of solutions to mitigate MCPD diester levels in oils from various stages of palm oil production. Partially refined palm oil samples and oil extracted from fresh palm fruits were submitted to bench-top deodorisation experiments. Application of glycerol and ethanol as refining aids during the deodorisation of refined-bleached palm oil proved to be moderately effective; about 25%-35% reduction of MCPD diester levels was achieved. Washing crude palm oil with ethanol-water (1:1) prior to deodorisation was also an effective strategy yielding an ～30% reduction of MCPD diester contents. Washing palm fruit pulp before oil extraction, however, was most impactful, resulting in a 95% reduction of MCPD diesters when compared to the deodorised control oil. This suggests that intervention upstream in the process chain is most efficient in reducing levels of these contaminants in refined oils. Following the study, a root-cause analysis was performed in order to map the parameters potentially responsible for the occurrence of MCPD diesters in refined palm oil and related fractions.