Study on rubber blends: Influence of epoxidation on phase morphology and interphase

A discussion about phase morphology and interphase is presented taking into account the influence of the epoxidation on NR/SBR blends. Unfilled blends were examined in a broad composition range to investigate the morphology by TEM (transmission electron microscopy) and to estimate the volume fraction of the interphase by means of DMA (dynamic mechanical analysis). It was observed that the domain sizes and the volume fraction of the interphase depend on the difference in polarity of rubbers caused by the presence of the epoxidized phase and the polarizability caused by the difference on the vinyl content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2377–2384, 2007     

Production of mycotoxins byFusarium species isolated in Germany

Summary Cultures ofFusarium tricinctum 434 formed large amounts of the trichothecene mycotoxins deoxynivalenol (DON) and 3-acetyldeoxynivalenol (AcDON), as well as the macrocyclic secondary metabolite zearalenone on moistened, autoclaved maize, rice and oats. The formation of zearalenone was low, with levels from 15 to 72 mg/kg as compared to the trichothecene production with maximum quantities of 917 mg/kg of AcDON on rice and 750 mg/kg DON on oats. In the cultures ofF. graminearum 183, total mycotoxin amounts found were lower, with maximum levels of zearalenone up to 150 mg/kg and AcDON up to 160 mg/kg on rice. DON, however, was produced in quantities of about 740 mg/kg on rice.

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Produktion von Mykotoxinen durch in Deutschland isolierte Fusarium-Arten1. Zeitverlauf der Deoxynivalenol-, 3-Acetyldeoxynivalenol-, und Zearalenon-Bildung auf festen Substraten

Zusammenfassung Kulturen vonFusarium tricinctum 434 bildeten auf feuchtem, autoklaviertem Mais, Reis bzw. Hafer relativ hohe Mengen der Trichothecen-Mykotoxine Deoxynivalenol (DON) und 3-Acetyldeoxynivalenol (AcDON) sowie das zu den makrocyclischen Lactonen zählende Mykotoxin Zearalenon. Die Zearalenonbildung war mit Werten von 15 bis 72 mg/kg gegenüber der Trichothecenproduktion mit maximal 917 mg/kg AcDON auf Reis und 750 mg/kg DON auf Hafer deutlich niedriger. In den Kulturen vonF. graminearum 183 wurden insgesamt geringere Toxinmengen gefunden mit maximalen Zearalenon-konzentrationen bis zu 150 mg/kg sowie AcDON Mengen bis zu 160 mg/kg auf Reis. Dagegen erreichte die DON-Bildung auf Reis 740 mg/kg.

     

Improved estimation of the resistivity of pure copper and electrical determination of thin copper film dimensions

Improved values for the resistivity, ρ, of pure, bulk copper from 50 to 1200 K, and their confidence intervals, are developed by extending the analysis of Matula. A recommended value for dρ/dT and its confidence interval in the temperature range of 290–425 K is developed for use with Matthiessen's rule to calculate the electrical thickness of thin copper films and the cross-sectional area of copper lines from resistance measurements at two temperatures. Error analyses are used to estimate the uncertainty with which the electrical thickness and cross-sectional area can be determined. Values for the temperature coefficient of resistance of pure, bulk copper are also provided.     

The role of native grammars in correcting errors in second language learning

This paper describes VP², a system that has been implemented to tutor nonnative speakers in English. This system differs from many tutoring systems by employing an explicit grammar of its user's native language. This grammar enables VP² to customize its responses by addressing problems due to interference of the native language. The system focuses on the acquisition of English verb-particle and verb-prepositional phrase constructions. Its correction strategy is based upon comparison of the native language grammar with an English grammar. VP² is a modular system: its grammar of a user's native language can easily be replaced by a grammar of another language. The problems and solutions presented in this paper are related to the more general question of how modelling previous knowledge facilitates instruction in a new skill.     

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Improving 2‐phenylethanol and 6‐pentyl‐α‐pyrone production with fungi by microparticle‐enhanced cultivation (MPEC)

Trichoderma atroviride IMI 206040 synthesizes the coconut lactone 6‐pentyl‐α‐pyrone (6‐PAP) de novo and Aspergillus niger DSM 821 produces the rose‐like flavour compound 2‐phenylethanol (2‐PE) from the precursor l ‐phenylalanine. Here, microparticles of different chemical composition and nominal particle diameter in the range 5–250 µm were added to shake‐flask cultures of both fungi to investigate the particles' effect on product formation. Maximum 2‐PE concentration increased by a factor of 1.3 to 1430 mg/l with the addition of 2% w/v talc (40 µm diameter). Maximum 6‐PAP concentration increased by a factor of 2 to 40 mg/l with the addition of 2% w/v iron (II, III) oxide. The influence of ions leaching out of the particles was investigated by cultivating the fungi in leached particle medium. For the first time, the positive effect of the microparticle‐enhanced cultivation (MPEC) technique on the microbial production of volatile metabolites, here flavour compounds from submerged fungal cultures, is demonstrated. The effect is strain‐ and particle‐specific. Copyright © 2014 John Wiley & Sons, Ltd.     

Fiber scaffolds of polysialic acid via electrospinning for peripheral nerve regeneration

Fiber scaffolds of bioactive polysialic acid have been prepared via electrospinning for peripheral nerve regeneration. The diameter, morphology and alignment of fibers in scaffolds were adjusted by variation of electrospinning parameters, which are decisive for the cell-scaffold interaction. Due to the high water solubility of polysialic acid (poly-α-2,8-N-acetylneuraminic acid) a photoactive derivative (poly-α-2,8-N-pentenoylneuraminic acid) was used to obtain stable fiber scaffolds in water by photochemical crosslinking. At the optimized fiber scaffolds good cell viability and directed cell proliferation along the fibers was achieved by cell tests with immortalized Schwann cells.     

Electromagnetic simulation of bonding wires and comparison withwide band measurements

Several typical bonding wire configurations have been measured in a frequency range up to 20 GHz using a vector network analyzer. Based on scanning electron microscope (SEM) pictures all bonding wires have been discretized and orthogonal grids suitable for electromagnetic simulation have been generated. Full wave finite difference time domain (FDTD) simulations as well as static and quasi static inductance extraction using a new Monte Carlo technique and FastHenry as well as capacitance extraction with a finite element method have been carried out. Numerical results are compared to measured scattering parameters and their quality and frequency dependence is discussed. All simulation techniques are evaluated with respect to their computational effort