For the first time, propagation rate coefficients, kp,COPO, for the copolymerizations of vinylidene fluoride and hexafluoropropene have been determined. The kinetic data was determined via pulsed‐laser polymerization in conjunction with polymer analysis via size‐exclusion chromatography, the PLP‐SEC technique. The experiments were carried out in homogeneous phase with supercritical CO2 as solvent for temperatures ranging from 45 to 90 °C. Absolute polymer molecular weights were calculated on the basis of experimentally determined Mark–Houwink constants. The Arrhenius parameters of kp,COPO vary significantly compared with ethene, which is explained by the high electronegativity of fluorine and less intra‐ and intermolecular interactions between the partially fluorinated macroradicals. 相似文献
Dear pss readers, As the previous year approached its end, news on three excellent prize winnings and nominations of pss authors and editors reached us: Gerhard Abstreiter of TU Munich will receive the Stern–Gerlach Medal 2014, the highest prize of the German Physical Society for experimental physics, honoring his work on low‐dimensional electron systems in semiconductor hetero‐ and nanostructures. His Review@RRL on InGaAs nanowires on silicon is opening the 2014 volume of pss (RRL) [1]. It is a welcome addition to our recent successful Focus Issue on Semiconductor Nanowires [2]. Our long‐term Editorial Advisory Board member, Wiley author and Guest Editor, Rainer Waser of RWTH Aachen and Research Centre Jülich, is one of the 11 winners of the highly prestigious Leibniz Prize for his outstanding research on nanoelectronics, especially oxides, ferroelectrics and resistive switching [3, 4]. Last but not least, one of the three nominated teams for the German Future Prize has been led by Wolfgang Schnick , LMU Munich, and Peter J. Schmidt , Philips Lumileds Aachen. Their groundbreaking work on new phosphor materials in white light emitting diodes (LEDs) for solid‐state lighting [5] goes back to a highly‐cited pss (a) article from 2005 [6] (see figure). The technology is now being commercialized and expected to enable energy savings on a grand scale in the coming years. Speaking of energy, research results related to this global challenge have been important throughout the year, touching areas such as thermoelectrics [7], efficiency of organic LEDs [8] and photovoltaics [9]. The latter field is even better represented since the recent introduction of our section rrl solar, covering solar cell materials or device development and characterization (see Editorial [10]). The full‐paper sister journals pss (a) and (b) presented an unprecedented number of high‐profile special issues in 2013 [11–15]. With heartfelt gratitude we look back onto fruitful collaboration with highly engaged guest editors, who helped bring to light issues such as the “Advanced Concepts for Silicon Based Photovoltaics” [11], the “Quantum Criticality and Novel Phases” [12], the “Disorder in Order: A special issue on amorphous materials” [13], the “Substrate Interactions in Heterogeneous Catalysis” [14], and the “Quantum Transport at the Molecular Scale” [15] among other interesting topical issues and sections. Both contributors and fine articles are too numerous to do justice to all of them here. We must restrict ourselves to a general invitation to browse this content, only hinting a few possible starting points, such as topological insulators [16], molecular electronics [17] and quantum phase transitions [18].
The paper introduces semantic and algorithmic methods for establishing a variant of the analytic subformula property (called ‘the bounded proof property’, bpp) for modal propositional logics. The bpp is much weaker property than full cut-elimination, but it is nevertheless sufficient for establishing decidability results. Our methodology originated from tools and techniques developed on one side within the algebraic/coalgebraic literature dealing with free algebra constructions and on the other side from classical correspondence theory in modal logic. As such, our approach is orthogonal to recent literature based on proof-theoretic methods and, in a way, complements it. 相似文献
Caged in : The formation of a complex between a peptide ligand and a major histocompatibility complex (MHC) class II protein is detected by a 129Xe biosensor. Cryptophane molecules that trap Xe atoms are modified with a hemagglutinin (HA) peptide, which binds to the MHC protein. The interaction can be monitored by an NMR chemical shift change of cage–HA bound 129Xe.
Food allergies have become an important health issue especially in industrialized countries. Undeclared allergenic ingredients
or the presence of “hidden” allergens because of contamination during the food production process pose great health risks
to sensitised individuals. The EU directive for food labelling lists allergenic foods that have to be declared on food products
by the manufacturers. The list includes gluten-containing cereals, crustaceans, eggs, fish, peanuts, soybeans, milk, various
nuts (e.g. almond, hazelnut, and walnut, etc.), celery, mustard, sesame seeds, lupin, and molluscs. Reliable methods for detection
and quantification of food allergens are needed that can be applied in a fast and easy-to-use manner, are portable, and need
only limited technical equipment. This review focuses on the latest developments in food allergen analysis with special emphasis
on fast immunoanalytical methods such as rapid enzyme-linked immunosorbent assays (ELISA), lateral-flow immunochromatographic
assays (LFA) and dipstick tests. Emerging technologies such as immunochemical microarrays and biosensors are also discussed
and their application to food allergen analysis is reviewed. Finally, a comprehensive overview of rapid immunochemical test
kits that are currently available commercially is given in tabular form. 相似文献
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play a crucial role in chemical signaling processes of biological
cells. Electrochemistry is one of the rare methods able to directly detect these species. ROS and RNS can be monitored in
the local microenvironment of cells in real time at the site where the actual signaling takes place. This review presents
recent advances made with amperometric electrochemical techniques. Existing challenges for the quantification of ROS and RNS
in biological systems are discussed to promote the development of innovative and reliable cell-based assays.
Figure Reactive oxygen and nitrogen species (ROS & RNS) are produced biological cells. An amperometric sensor is placed in close
proximity. The recorded current I is used to determine fluxes of certain species.
The paper reports on the fabrication and electrochemical investigation of boron-doped diamond nanowires (BDD NWs) electrodes. The nanowires were obtained directly from highly doped polycrystalline diamond substrates using reactive ion etching (RIE) with oxygen plasma. The technique does not require any complicated processing steps such as mask deposition or template removal. The influence of the surface state on the electrochemical characteristics is discussed. The interface with the most favourable electrochemical response is investigated for the detection of tryptophan using differential pulse voltammetry. A detection limit of 5 × 10?7 M was obtained on oxidized BDD NWs, as compared to 1 × 10?5 M recorded on planar oxidized boron-doped diamond interfaces. 相似文献
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a powerful technique for the
determination of metal and nonmetal distributions within biological systems with high sensitivity. An imaging LA-ICP-MS technique
for Fe, Cu, Zn, and Mn was developed to produce large series of quantitative element maps in native brain sections of mice
subchronically intoxicated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP) as a model of Parkinson’s disease. Images
were calibrated using matrix-matched laboratory standards. A software solution allowing a precise delineation of anatomical
structures was implemented. Coronal brain sections were analyzed crossing the striatum and the substantia nigra, respectively.
Animals sacrificed 2 h, 7 d, or 28 d after the last MPTP injection and controls were investigated. 相似文献