Trennung Isomerer Alkohole Mittels der Gas-Flüssig-Chromatographie, 2. Mitt.:

Zusammenfassung 15 isomere Alkohole C₈H₁₈O, unter welchen sich normale und verzweigte, primäre, sekundäre und tertiäre befanden, und deren Siedepunkte um etwa 50° auseinanderliegen, wurden mit drei verschiedenen stationären Phasen untersucht. Gute Trennbarkeit der Isomeren hängt nicht nur von ihrer Siedepunktsdifferenz ab. In Gemischen liegen dieR _z -Werte nicht immer genau dort, wo die der Einzelkomponenten gefunden wurden. Während in günstigen Fällen noch 6 Isomere als 6 Zacken (Schultern) nebeneinander nachgewiesen werden konnten, gaben komplexere Mischungen, z. B. aller 15 untersuchten Alkohole, maximal 10 Zakken bzw. Schultern.Mit 3 Abbildungen     

Nondestructive analysis of single rapeseeds by means of Raman spectroscopy

The value of different vegetable oils can be correlated with the content of polyunsaturated fatty acids, especially omega‐3‐fatty acids such as linolenic acid, because of their contribution to healthy nutrition. One expression for the degree of unsaturation is the iodine value normally measured with gas chromatography. The use of Raman spectroscopy allows a rapid calculation of the iodine value and, in addition, only in a minimal sample volume. Therefore, this method can be used in single rapeseeds in order to predict the iodine value before harvesting. Additionally, the method can also be used for breeding investigations. Here, the lipid content and composition of a plant can be predicted by measuring the seedling without destruction. Copyright © 2006 John Wiley & Sons, Ltd.     

The Effective Theory of Strings

We show that the Nambu–Goto string, and its higher dimensional generalizations, can be quantized, in the sense of an effective theory, in any dimension of the target space. The crucial point is to consider expansions around classical string configurations. We are using tools from perturbative algebraic quantum field theory, quantum field theory on curved spacetimes, and the Batalin–Vilkovisky formalism. Our model has some similarities with the Lüscher–Weisz string, but we allow for arbitrary classical background string configurations and keep the diffeomorphism invariance.     

Decomposition of partial orders

A decomposition theory for partial orders which arises from the split decomposition of submodular functions is introduced. As a consequence of this theory, any partial order has a unique decomposition consisting of indecomposable partial orders and certain highly decomposable partial orders. The highly decomposable partial orders are completely characterized. As a special case of partial orders, we consider lattices and distributive lattices. It occurs, that the highly decomposable distributive lattices are precisely the Boolean lattices.     

Insufficiency of four known necessary conditions on string unavoidability

The reductive decision procedure for unavoidable strings was recently shown to have an exponential lower bound. Hence, as a special case of generalized pattern matching, the existence of an efficient algorithm deciding string unavoidability remains an interesting open question. It has been hypothesized that some combination of the four necessary conditions implied by the known decidability results would be sufficient. Three of these criteria are determined in polynomial time, and the fourth provides the needed recursion. In this paper, however, we demonstrate the existence of arbitrarily many avoidable strings meeting any extended conjunction of the four necessary conditions. These insufficiency results are achieved by analyzing the appropriate graphical interpretations of the given algorithms. We provide a new combinatorial operation on the corresponding strings and generate arbitrary counterexamples from an empirically located minimal set. Thus, string unavoidability cannot be efficiently decided by the known reductive method or its immediate implications.     

Metabolism and toxicological detection of the designer drug 4-chloro-2,5-dimethoxyamphetamine in rat urine using gas chromatography-mass spectrometry

Studies are described on the metabolism and the toxicological analysis of the amphetamine-derived designer drug 4-chloro-2,5-dimethoxyamphetamine (DOC) in rat urine using gas chromatographic-mass spectrometric techniques. The metabolites identified indicated that DOC was metabolized by O-demethylation at position 2 or 5 of the phenyl ring partly followed by glucuronidation and/or sulfation. The authors’ systematic toxicological analysis procedure using full-scan gas chromatography-mass spectrometry after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of an intake of a dose of DOC in rat urine that corresponds to a common drug user’s dose. Assuming similar metabolism, the STA procedure described should be suitable as proof of an intake of DOC in human urine.     

An Affinity Reagent for the Recognition of Pyrophosphorylated Peptides

A resin‐bound dinuclear zinc(II) complex for the selective capture of pyrophosphopeptides is reported. The metal complex binds diphosphate esters over other anionic groups, such as monophosphate esters, sulfate esters, and carboxylic acids, with high specificity. Immobilization of the compound provided a reagent capable of binding and retaining nanomolar quantities of pyrophosphopeptide in the presence of cell lysate. The high affinity and specificity of the reagent makes it an attractive tool for the study of in vivo pyrophosphorylation.     

Development and independent laboratory validation of a simple method for the determination of paraquat and diquat in potato, cereals and pulses

A new sensitive, fast and robust method for the determination of paraquat and diquat residues in potatoes, cereals and pulses is presented. Different extraction conditions (solvent, time and temperature) have been evaluated using barley grain, potatoes and dry lentils containing incurred residues of diquat and paraquat. The finalised procedure involves extraction with a mixture of methanol/water/hydrochloric acid at 80?°C and analysis by liquid chromatography–tandem mass spectrometry. Diquat D4 and Paraquat D6 internal standards were added to the test portions prior to extraction. A small-scale inter-laboratory validation of the developed method for diquat and paraquat using potato and barley samples was conducted by three laboratories. The precision and accuracy of the method were determined from recovery experiments (five replicates) at 0.01 and 0.1?mg?kg^?1. The recoveries obtained (n?=?180) were in the range of 92–120?% with associated relative standard deviation (RSD) between 1.4–10?% for all compound/commodity/spiking concentration combinations.     

Dependence modeling in non-life insurance using the Bernstein copula

This paper illustrates the modeling of dependence structures of non-life insurance risks using the Bernstein copula. We conduct a goodness-of-fit analysis and compare the Bernstein copula with other widely used copulas. Then, we illustrate the use of the Bernstein copula in a value-at-risk and tail-value-at-risk simulation study. For both analyses we utilize German claims data on storm, flood, and water damage insurance for calibration. Our results highlight the advantages of the Bernstein copula, including its flexibility in mapping inhomogeneous dependence structures and its easy use in a simulation context due to its representation as mixture of independent Beta densities. Practitioners and regulators working toward appropriate modeling of dependences in a risk management and solvency context can benefit from our results.     

Scenario tree modeling for multistage stochastic programs

An important issue for solving multistage stochastic programs consists in the approximate representation of the (multivariate) stochastic input process in the form of a scenario tree. In this paper, we develop (stability) theory-based heuristics for generating scenario trees out of an initial set of scenarios. They are based on forward or backward algorithms for tree generation consisting of recursive scenario reduction and bundling steps. Conditions are established implying closeness of optimal values of the original process and its tree approximation, respectively, by relying on a recent stability result in Heitsch, Römisch and Strugarek (SIAM J Optim 17:511–525, 2006) for multistage stochastic programs. Numerical experience is reported for constructing multivariate scenario trees in electricity portfolio management.