d- andl-Lactate determination in dairy products: Presentation of a fast automated analysis system

A flow-injection system is presented, which is versatile, automated and has an integrated enzyme system. Its efficiency at determiningd- andl-lactate separately in dairy products is compared with the officially used reference method (DIN 10335). By means of a mathematical elimination of matrix effects, the pretreatment steps can be clearly reduced. As a result of the immobilization of the enzymes, an appropriate automation software and an adaptation of the system developed to the given medium, the analysis could be performed within 5 min and was distinctly cheaper than alternative methods. The values determined in 15 different dairy products deviated from those of the reference method by 3% at a maximum.     

Crystallization of S-layer protein lattices on surfaces and interfaces

A review is given on the structure, chemistry, and assembly of crystalline bacterial cell surface layers (S-layers). S-layers composed of single protein or glycoprotein species represent the most common cell surface structures observed in prokaryotic organisms. Isolated S-layer proteins possess the intrinsic property for recrystallization into isoporous monomolecular arrays in suspension and at a broad spectrum of surfaces (e.g. silicon, metals, polymers) and interfaces (e.g. air–liquid interface or lipid films). The well-defined arrangement of functional groups on S-layer lattices allows the binding of functional molecules (e.g. enzymes, antibodies, ligands) and particles in defined regular arrays. S-layers also represent templates for the formation of inorganic nanocrystal superlattices (e.g. Au, CdS, Pt) as required for molecular electronics and non-linear optics. Finally, S-layers can be used as the structural basis for a biomolecular construction kit involving all major species of biological molecules for applications in molecular nanotechnology, nanobiotechnology and biomimetics.     

Psychoanalysis and hypnoanalysis: A professional history and a challenge.

Describes the professional development and work of the present author, including her involvement with psychoanalysis, work with hypnosis, and clinical work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comorbidity of anxiety and depression in youth: Treatment implications.

Reviews the empirical literature on the comorbidity of anxiety and depressive disorders in youth, emphasizing prevalence of comorbidity, difficulties in assessment and measurement, familial factors, and developmental differences. The nature of anxiety and of depression in youth is examined (e.g., differentiating cognitive deficiencies from cognitive distortions), and treatment recommendations are presented from a cognitive-behavioral framework. Components of the treatment include affective education, enactive programming, addressing reinforcement difficulties, correcting cognitive distortions, and enhancing problem-solving skills. Peer and familial factors are discussed. Successful treatment of comorbid children relies on a flexible application of these strategies with consideration of the developmental level and particular symptom constellation of the individual child. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New diketopyrrolopyrrole based D–A–D π-conjugated molecules: Synthesis,optical, electrochemical,morphological and photovoltaic properties

Two solution processable donor–acceptor, π-conjugated molecules that consist of diketopyrrolopyrrole (DPP) central acceptor unit with dibenzofuran (DPP-DBF) or acenaphtene (DPP-ACN) donor substituents, were prepared by Suzuki coupling reaction. The optical, electrochemical and film forming properties of these D–A–D molecules were investigated and used as active materials in bulk heterojunction solar cells.     

Polyazines and Polyazomethines with Didodecylthiophene Units for Selective Dispersion of Semiconducting Single‐Walled Carbon Nanotubes

Polymer wrapped single‐walled carbon nanotubes (SWNTs) have been demonstrated to be a very efficient technique to obtain high purity semiconducting SWNT solutions. However, the extraction yield of this technique is low compared to other techniques. Poly‐alkyl‐thiophenes have been reported to show higher extraction yield compare to polyfluorene derivatives. Here, the affinity for semiconducting SWNTs of two polymers with a backbone containing didodecylthiophene units interspersed with N atoms is reported. It is demonstrated that one of the polymers, namely, poly(2,5‐dimethylidynenitrilo‐3,4‐didodecylthienylene) (PAMDD), has very high semiconducting SWNT extraction yield compared to the poly(3,4‐didodecylthienylene)azine (PAZDD). The dissimilar wrapping efficiency of these two polymers for semiconducting SWNTs is attributed to the interplay between the affinity for the nitrogen atoms of the highly polarizable walls of SWNTs and the mechanical flexibility of the polymer backbones. Photoluminescence (PL) measurements demonstrate the presence of metallic tubes and SWNT bundles in the sample selected with PAZDD and higher purity of SWNT‐PAMDD samples. The high purity of the semiconducting SWNTs selected by PAMDD is further demonstrated by the high performance of the solution‐processed field‐effect transistors (FETs) fabricated using a blade coating technique, which exhibit hole mobilities up to 33.3 cm² V^?1 s^?1 with on/off ratios of 10⁶.     

Technological learning in bioenergy systems

The main goal of this article is to determine whether cost reductions in different bioenergy systems can be quantified using the experience curve approach, and how specific issues (arising from the complexity of biomass energy systems) can be addressed. This is pursued by case studies on biofuelled combined heat and power (CHP) plants in Sweden, global development of fluidized bed boilers and Danish biogas plants. As secondary goal, the aim is to identify learning mechanisms behind technology development and cost reduction for the biomass energy systems investigated. The case studies reveal large difficulties to devise empirical experience curves for investment costs of biomass-fuelled power plants. To some extent, this is due to lack of (detailed) data. The main reason, however, are varying plant costs due to differences in scale, fuel type, plant layout, region etc. For fluidized bed boiler plants built on a global level, progress ratios (PRs) for the price of entire plants lies approximately between 90–93% (which is typical for large plant-like technologies). The costs for the boiler section alone was found to decline much faster. The experience curve approach delivers better results, when the production costs of the final energy carrier are analyzed. Electricity from biofuelled CHP-plants yields PRs of 91–92%, i.e. an 8–9% reduction of electricity production costs with each cumulative doubling of electricity production. The experience curve for biogas production displays a PR of 85% from 1984 to the beginning of 1990, and then levels to approximately 100% until 2002. For technologies developed on a local level (e.g. biogas plants), learning-by-using and learning-by-interacting are important learning mechanism, while for CHP plants utilizing fluidized bed boilers, upscaling is probably one of the main mechanisms behind cost reductions.     

Enrichment of H(2)(17)O from tap water, characterization of the enriched water, and properties of several (17)O-labeled compounds

A low-abundance form of water, H(2)(17)O, was enriched from 0.04% to ～90% by slow evaporation and fractional distillation of tap water. The density and refractive index for H(2)(17)O are reported. Gas chromatography-mass spectrometry (GC-MS) of (16)O- and (17)O-1-hexanols and their trimethyl silyl ethers and of (16)O- and (17)O-hexamethyl disiloxanes was used to determine the percentage of (17)O enrichment in the H(2)(17)O. Furthermore, the chemical shifts of labeled and nonlabeled water dissolved in CDCl(3) differed sufficiently that we could verify the enrichment of H(2)(17)O. (17)O hexanol was synthesized by the reaction of iodohexane with Na(17)OH. (17)O-Labeled trimethylsilanol and (17)O-labeled hexamethyldisiloxane were prepared by the reaction of H(2)(17)O with bis(trimethylsilyl)trifluoroacetamide (BSTFA). To generate standards for (17)O NMR, H(2)(17)O(2), and (17)O camphor were prepared. H(2)(17)O was electrolyzed to form (17)O-labeled hydrogen peroxide which was quantified using two colorimetric assays. (17)O-Labeled camphor was prepared by exchanging the ketone oxygen of camphor using H(2)(17)O. The (17)O-labeled compounds were characterized using (17)O, (1)H, and (13)C NMR and GC-MS. While we were characterizing the labeled camphor, we also detected an unexpected oxygen exchange reaction of primary alcohols, catalyzed by electrophilic ketones such as camphor. The reaction is a displacement of the alcohol OH group by water. This is an example of the usefulness of (17)O NMR in the study of a reaction mechanism that has not been noticed previously.     

From bulk to single-cell classification of the filamentous growing Streptomyces bacteria by means of Raman spectroscopy

Classification of Raman spectra recorded from single cells is commonly applied to bacteria that exhibit small sizes of approximately 1 to 2 μm. Here, we study the possibility to adopt this classification approach to filamentous bacteria of the genus Streptomyces. The hyphae can reach extensive lengths of up to 35 μm, which can correspond to a single cell identified in light microscopy. The classification of Raman bulk spectra will be demonstrated. Here, ultraviolet resonance Raman (UV RR) spectroscopy is chosen to classify six Streptomyces species by the application of a tree-like classifier. For each knot of the hierarchical classifier, estimated classification accuracies of over 94% are accomplished. In contrast to the classification of bulk spectra, the classification of single-cell spectra requires a homogenous substance distribution within the cell. Consequently, the bacterial cell chemistry can be represented by one individual spectrum. This requirement is not fulfilled when different spectra are processed from different locations within the cell. Bacteria of the investigated genus Streptomyces exhibit, besides the normal bacterial spectra, lipid-rich spectra. The occurrence of lipid enrichment depends on culture age and nutrition availability. With this study, we investigate the cell substance distribution, especially of lipid-rich fractions. The classification utilizing a tree-like classifier is also applied to the Streptomyces single-cell spectra, resulting in classification accuracies between 80 and 93% for the investigated Streptomyces species.