Structural effects of compatibilizer localization and effectivity in thermoplastic polyurethane–polyolefin blends

A study was performed with blends of thermoplastic polyurethanes and polyolefins to determine the structural requirements for a compatibilizer to be located at the interface. It was demonstrated that during the addition of an incompatible polymeric additive (i.e., incompatible with both blend constituents) to a polyurethane–polyolefin blend, the additive migrated to the interface. This interfacial phenomenon was proven to be virtually independent of compatibilizer viscosity or surface activity. Only when the compatibilizer was quite comparable to one of the phases did small differences in polarity govern whether the compatibilizer remained at the interface or formed micelles. This effect was demonstrated with a series of styrene–(ethylene–butylene)–styrene block copolymer compatibilizers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2901–2905, 2002; DOI 10.1002/app.10285     

Bioimaging TOF-SIMS: High resolution 3D imaging of single cells

The distribution of phosphocholine ions (m/z 184, m/z 86), sodium ions, and potassium ions in thyroid tumor cells was analyzed by imaging TOF-SIMS. Repeated sputtering with a C(60) (+) source and subsequent analysis with a Bi(3) (+) gun produced a series of 138 images that were stacked to make a 3D display of the chemistry of cells. Phosphocholine was seen in the plasma membrane (m/z 184) and intracellular membranes (m/z 86). The different fragmentation of the phospholipid probably reflects the chemical composition of membranes at these sites. High intensity of secondary ion signals of potassium was seen in membrane-encompassed cellular compartments. The data indicate that potassium ions are compartmentalized in thyroid tumor cells.     

Localization of fatty acids with selective chain length by imaging time-of-flight secondary ion mass spectrometry

Localization of fatty acids in biological tissues was made by using TOF-SIMS (time-of-flight secondary ion mass spectrometry). Two cell-types with a specific fatty acid distribution are shown. In rat cerebellum, different distribution patterns of stearic acid (C18:0), palmitic acid (C16:0), and oleic acid (C18:1) were found. Stearic acid signals were observed accumulated in Purkinje cells with high intensities inside the cell, but not in the nucleus region. The signals colocalized with high intensity signals of the phosphocholine head group, indicating origin from phosphatidylcholine or sphingomyelin. In mouse intestine, high palmitic acid signals were found in the secretory crypt cells together with high levels of phosphorylinositol colocalized in the crypt region. Palmitic acid was also seen in the intestinal lumen that contains high amounts of mucine, which is known to be produced in the crypt cells. Linoleic acid signals (C18:2) were low in the crypt region and high in the villus region. Oleic acid signals were seen in the villi and stearic acid signals were ubiquitous with no specific localization in the intestine. We conclude that the results obtained by using imaging TOF-SIMS are consistent with known brain and intestine biochemistry and that the localization of fatty acids is specific in differentiated cells.     

Technologies for value creation: an exploration of remote diagnostics systems in the manufacturing industry

Abstract.  With firms increasingly relying on ubiquitous computing to implement major business initiatives, it is becoming ever more necessary to understand the technological aspects of business developments. This paper analyzes the use of remote diagnostics systems in the manufacturing industry and discusses the opportunities and challenges for the early adopters. It pays specific attention to the impact on business aspects such as the value creation process consisting of relationships, roles, and architecture and the value proposal consisting of a business offer and customer value. The study shows how ubiquitous computing allows manufacturers to become remote service providers while customers can either become co-creators of value or passive receivers of created value. Ubiquitous computing also creates possibilities for the manufacturing industry to design new kinds of business offers based on remote presence. Studying remote diagnostics systems shows that ubiquitous computing creates value when deployed in products, and not just in relation to individuals. Moreover, the design of the value-creation process should not be limited to the single supplier or customer organization, as ubiquitous computing applications take no notice of organizational boundaries.     

Mechanical activation and cement formation of trimagnesium phosphate

Magnesium phosphate cements have attracted an increasing attention for biomedical applications in the past years due to their high mechanical performance and fast in vivo degradation at bony implantation sites. Cements are usually multicomponent mixtures of cement raw powders and setting regulators, whereas the latter may have a detrimental effect on the biocompatibility. Here, we demonstrate that following prolonged grinding of trimagnesium phosphate (Mg₃(PO₄)₂, farringtonite), a mechanically induced disordering reaction strongly altered farringtonite reactivity such that self‐setting cements without further components were formed with a compressive strength of up to 11 MPa. Time‐resolved X‐ray diffraction analysis revealed that the formation of a nanocrystalline magnesium phosphate phase during grinding was responsible for cement setting to the highly hydrated magnesium phosphate mineral cattiite (Mg_3[(PO₄)₂?22H₂O), whereas crystalline farringtonite showed practically no setting reaction.     

Gold nanolenses generated by laser ablation-efficient enhancing structure for surface enhanced Raman scattering analytics and sensing

Nanoaggregates formed by metal spheres of different radii and interparticle distances represent finite, deterministic, self-similar systems that efficiently concentrate optical fields and act as "nanolenses". Here we verify experimentally the theoretical concept of nanolenses and explore their potential as enhancing nanostructures in surface enhanced Raman scattering (SERS). Self-similar structures formed by gold nanospheres of different sizes are generated by laser ablation from solid gold into water. These nanolenses exhibit SERS enhancement factors on the order of 10(9). The "chemically clean" preparation process provides several advantages over chemically prepared nanoaggregates and makes the stable and biocompatible gold nanolenses potent enhancing structures for various analytical and sensing applications.     

Highly porous TiO2 films from anodically deposited titanate hybrids and their photoelectrochemical and photocatalytic activity

Hybrid films of TiO₂ and benzoquinone, its derivative 2-methyl-benzoquinone or the dye 2,9,16,23-tetrasulfophthalocyaninatonickel(II) were prepared by anodic electrodeposition from titanium alkoxide solutions. Calcination of the films at 450 °C led to removal of the organics and the formation of crystalline and highly porous TiO₂ films as seen in XRD and Kr adsorption measurements, respectively. In dye-sensitized solar cells the films achieved an overall light-to-electricity conversion efficiency of 0.8% despite a low film thickness of 0.55 μm. In the photocatalytic decomposition of methylene blue the films showed photonic efficiencies of up to 0.09% for film thicknesses around 0.5 μm, which is much higher than those of comparable TiO₂ films prepared by sol–gel method.     

One- and two-photon excited optical ph probing for cells using surface-enhanced Raman and hyper-Raman nanosensors

We demonstrate spatially resolved probing and imaging of pH in live cells by mobile and biocompatible nanosensors using surface-enhanced Raman scattering (SERS) of 4-mercaptobenzoic acid (pMBA) on gold nanoaggregates. Moreover, we also show that this concept of pH nanosensors can be extended to two-photon excitation by using surface-enhanced hyper-Raman scattering (SEHRS). In addition to the advantages of two-photon excitation, the SEHRS sensor enables measurements over a wide pH range without the use of multiple probes.