Detection of lupine (Lupinus spp.) DNA in processed foods using real-time PCR

Materials from lupine (Lupinus spp.) plants are used as food ingredients. Even small amounts can evoke allergic reactions in sensitized individuals. The applicability of a recently developed real-time PCR method to the sensitive and specific detection of lupine DNA in processed foods was examined. Using the preparation of pizza as a model, changes in the amplification efficiency and in the limit of detection arising from various processing steps such as freezing and baking were observed. For the starting flour the same limit of detection (0.1 mg/kg) as in raw foods was determined. Freezing of the dough resulted in increased cycle threshold values compared to the flour and the prepared dough. In the baked pizza the detection limit was 1 mg/kg, thus demonstrating the suitability of the method for the detection of lupine DNA in processed foods.     

Impact of substrate material and annealing conditions on the microstructure and chemistry of yttria-stabilized-zirconia thin films

Si-diffusion from Si-based substrates into yttria-stabilized-zirconia (YSZ) thin films and its impact on their microstructure and chemistry is investigated. YSZ thin films used in electrochemical applications based on micro-electrochemical systems (MEMS) are deposited via spray pyrolysis onto silicon-based and silicon-free substrates, i.e. Si_xN_y-coated Si wafer, SiO₂ single crystals and Al₂O₃, sapphire. The samples are annealed at 600 °C and 1000 °C for 20 h in air. Transmission electron microscopy (TEM) showed that the Si_xN_y-coated Si wafer is oxidized to SiO_z at the interface to the YSZ thin film at temperatures as low as 600 °C. On all YSZ thin films, silica is detected by X-ray photoelectron spectroscopy (XPS). A particular large Si concentration of up to 11 at% is detected at the surface of the YSZ thin films when deposited on silicon-based substrates after annealing at 1000 °C. Their grain boundary mobility is reduced 2.5 times due to the incorporation of SiO₂. YSZ films on Si-based substrates annealed at 600 °C show a grain size gradient from the interface to the surface of 3 nm to 10 nm. For these films, the silicon content is about 1.5 at% at the thin film's surface.     

Adaptable and Reprogrammable Surfaces

Establishing control over chemical reactions on interfaces is a key challenge in contemporary surface and materials science, in particular when introducing well‐defined functionalities in a reversible fashion. Reprogrammable, adaptable and functional interfaces require sophisticated chemistries to precisely equip them with specific functionalities having tailored properties. In the last decade, reversible chemistries—both covalent and noncovalent—have paved the way to precision functionalize 2 or 3D structures that provide both spatial and temporal control. A critical literature assessment reveals that methodologies for writing and erasing substrates exist, yet are still far from reaching their full potential. It is thus critical to assess the current status and to identify avenues to overcome the existing limitations. Herein, the current state‐of‐the‐art in the field of reversible chemistry on surfaces is surveyed, while concomitantly identifying the challenges—not only synthetic but also in current surface characterization methods. The potential within reversible chemistry on surfaces to function as true writeable memories devices is identified, and the latest developments in readout technologies are discussed. Finally, we explore how spatial and temporal control over reversible, light‐induced chemistries has the potential to drive the future of functional interface design, especially when combined with powerful laser lithographic applications.     

On‐Chip Detection of Rolling Circle Amplified DNA Molecules from Bacillus Globigii Spores and Vibrio Cholerae

For the first time DNA coils formed by rolling circle amplification are quantified on‐chip by Brownian relaxation measurements on magnetic nanobeads using a magnetoresistive sensor. No external magnetic fields are required besides the magnetic field arising from the current through the sensor, which makes the setup very compact. Limits of detection down to 500 Bacillus globigii spores and 2 pM of Vibrio cholerae are demonstrated, which are on the same order of magnitude or lower than those achieved previously using a commercial macro‐scale AC susceptometer. The chip‐based readout is an important step towards the realization of field tests based on rolling circle amplification molecular analyses.     

Inventor collaboration over distance: a comparison of academic and corporate patents

Patenting is often done in collaboration with other inventors to integrate complementary and additional knowledge. The paper takes a spatial view of this issue and analyses the distances between inventors of German patents. We compare the distances between invention teams of German patent applications from 1993–2006 and distinguish between academic and corporate teams and those consisting of researchers from both domains (‘mixed teams’). Due to their different institutional backgrounds different types of proximity guide their spatial search for partners. The basic finding is that regional collaboration clearly prevails. However, the distance between collaborating inventors of corporate patents exceeds that of inventors of academic patents, but the largest distances can be found in science–industry collaborative patents. When excluding directly neighboured collaboration, which is likely to be in-house collaboration, the differences between academic and corporate teams vanish, but mixed teams still overcome longer distances.     

Laser-induced dissociation/high-energy collision-induced dissociation fragmentation using MALDI-TOF/TOF-MS instrumentation for the analysis of neutral and acidic oligosaccharides

Producing detailed mass spectrometric fragmentation data of native oligosaccharides for the purpose of basic structure elucidation has become a readily accessible tool since the availability of enhanced technical equipment. In this report, high-energy collision-induced dissociation (heCID) in combination with MALDI-TOF/TOF technology for analysis of native neutral and acidic oligosaccharides is described. By providing complementary data, heCID-MALDI-TOF/TOF adds a variety of valuable cross-ring fragmentation information to the information of glycosidic fragmentation obtained preferably by laser-induced dissociation (LID). We examined parameters influencing fragmentation behavior of both-acidic and neutral-compounds. Results show a dependency of the fragmentation pattern for the employed matrix as well as the laser intensity provided for the ionization of the analytes and the complexity of the analytes. Due to instrument-specific settings, protonated glycosidic ion series within spectra of sodiated compounds could also be identified. Furthermore, acquired spectra could be readily used to identify compounds by comparison to existing glycan databases such as GlycoSuiteDB and GlycosciencesDB. The results show a better scoring of heCID data sets in comparison to LID-derived data. heCID-MALDI-TOF/TOF analysis in combination with database search algorithms is demonstrated to be suitable for an initial identification/classification of carbohydrates.     

Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin‐Film Electrodes on YSZ Electrolyte

Agglomerated Pt thin films have been proposed as electrodes for electrochemical devices like micro‐solid oxide fuel cells (μ‐SOFCs) operating at low temperatures. However, comprehensive studies elucidating the interplay between agglomeration state and electrochemical properties are lacking. In this contribution the electrochemical performance of agglomerated and “dense” Pt thin film electrodes on yttria‐stabilized‐zirconia (YSZ) is correlated with their microstructural characteristics. Besides the microscopically measurable triple‐phase‐boundary (tpb) where Pt, YSZ and air are in contact, a considerable contribution of “nanoscopic” tpbs to the electrode conductivity resulting from oxygen permeable grain boundaries is identified. It is demonstrated that “dense” Pt thin films are excellent electrodes provided their grain size and thickness are in the nanometer range. The results disprove the prevailing idea that the performance of Pt thin film electrodes results from microscopic and geometrically measurable tpbs only.     

Thin‐Film Electrodes: Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin Film Electrodes on YSZ Electrolyte (Adv. Funct. Mater. 3/2011)

Agglomerated Pt thin films have been proposed as electrodes for electrochemical devices like micro‐solid oxide fuel cells (μ‐SOFCs) operating at low temperatures. However, comprehensive studies elucidating the interplay between agglomeration state and electrochemical properties are lacking. In this contribution the electrochemical performance of agglomerated and “dense” Pt thin film electrodes on yttria‐stabilized‐zirconia (YSZ) is correlated with their microstructural characteristics. Besides the microscopically measurable triple‐phase‐boundary (tpb) where Pt, YSZ and air are in contact, a considerable contribution of “nanoscopic” tpbs to the electrode conductivity resulting from oxygen permeable grain boundaries is identified. It is demonstrated that “dense” Pt thin films are excellent electrodes provided their grain size and thickness are in the nanometer range. The results disprove the prevailing idea that the performance of Pt thin film electrodes results from microscopic and geometrically measurable tpbs only.