Analysis of dithiocarbamate fungicides. Second-derivative UV-spectroscopic determination of CS2, COS, and thiram (TMTD)

The application of second-derivative UV-spectroscopy offers a highly sensitive and selective method for the determination of CS₂ and COS, as acid hydrolysis products of dithiocarbamate und thiuram disulphide fungicides, using a methanolic amine absorption reagent (ethylenediamine, piperidine). With standard concentrations of 0.08–1.1 g CS₂/ml and 0.3 to 2.0 g COS/ml, respectively, calibration curves with good correlation coefficients (r>0.999) were obtained. In comparison to the official method of the Deutsche Forschungsgemeinschaft (DFG method S15) the proposed alternative is at least 100 times more sensitive to CS₂. Using the second derivative method it is possible not only to clearly differentiate between CS₂ and COS but also to quantify both gases without resorting to tedious background corrections as compared to the direct photometric methods. Additionally, second derivative spectroscopy allows the direct determination of thiram in the concentration range 1–10 g/ml after its extraction with chloroform. For example, thiram in water (10 g/l) and in thiram/talc standards (10 mg/g) were determined with good precision (±2.0%).

---

Analytik der Dithiocarbamat-Fungicide. Bestimmung von CS₂, COS sowie Thiram (TMTD) mittels Derivativ-UV-Spektroskopie

Zusammenfassung Die Anwendung der Derivativ-UV-Spektroskopie (2. Ableitung) erlaubt eine sehr empfindliche Bestimmung von CS₂ und COS als Hydrolyseprodukte der Dithiocarbamat- und Thiuramdisulfid-Fungicide nach Absorption in einem methanolischem Amin-Reagens (Ethylendiamin, Piperidin). Mit Standard-Konzentrationen von 0,08–1,1 g CS₂/ml bzw. 0,3–2,0 g COS/ml zeigten die Eichgeraden gute Korrelationskoeffizienten (r<0,999). Im Vergleich zur DFG-Methode S15 zeichnet sich die vorgeschlagene Alternative durch eine um zwei Zehnerpotenzen höhere Empfindlichkeit bei der CS₂-Bestimmung aus. In der 2. Ableitung wird nicht nur die Unterscheidung von COS und CS₂ eindeutig, sondern auch deren Quantifizierung ohne rechnerische Untergrundkorrekturen ermöglicht. Mit Hilfe der Derivativspektroskopie konnte außerdem Thiram (TMTD) in Konzentrationen von 1–10 g/ml direkt erfaßt werden. So ließen sich nach Extraktion mit Chloroform 10 g/L Thiram in Wasser mit einer Präzision von ±2,0% direkt bestimmen oder Thiram/Talkum-Standards (10 mg/g) überprüfen.

     

Distributed Symbolic Bounded Property Checking

In this paper we describe an algorithm for distributed, BDD-based bounded property checking and its implementation in the verification tool SymC. The distributed algorithm verifies larger models and returns results faster than the sequential version.The core algorithm distributes partitions of the state set to computation nodes after reaching a threshold size. The nodes proceed with image computation on the nodes asynchronously. The main scalability problem of this scheme is the overlap of state set partitions. We present static and dynamic overlap reduction techniques.     

Hot Workability of as‐Cast High Manganese‐High Carbon Steels

In order to produce new high Mn‐high C austenitic steels (R_m>700 MPa), different tests and methods were used to determine a suitable window of process parameters. In‐situ melting hot tensile tests and hot compression tests were carried out to investigate the hot ductility, fracture characteristics and flow behaviour during continuous casting and hot deformation of 3 steels with Mn and C contents between 9‐23% and 0.6‐0.9%, respectively. The results show that these steels are susceptible to interdendritic fracture at high temperatures. Decreasing Mn content improves the reduction of area at high temperatures to 60% or more. Hot deformation loads for processing the investigated steels are not higher in comparison to the stainless steel 1.4301.     

Immunosensor with self-referencing based on surface plasmon diffraction

We propose a novel type of immunosensor based on the diffraction of surface plasmon, which allows for in situ, real-time, and label-free observation of interfacial binding events. The inherent self-referencing mechanism of surface diffraction was found to be very effective for compensating fluctuations of the bulk, demonstrated by a temperature variation experiment. Possessing a stable baseline signal, the diffraction sensor offered picomolar sensitivity in directly detecting the binding of human chorionic gonadotropin (hCG) hormone.     

AI and the Conquest of Complexity in Law

The paper identifies some of the problems with legal systems and outlines the potential of AI technology for overcoming them. For expository purposes, this outline is based on a simplified epistemology of the primary functions of law. Social and philosophical impediments from the side of the legal community to taking advantage of the potential of this technology are discussed and strategic recommendations are given. What is possible is not independent of what we believe to be possible. The possibilities of such developments in the practical world depends upon their being grasped imaginatively by the people who make the practical world work. Neil MacCormick (1993, p.18)     

ZnO nanocrystals synthesized by physical vapor deposition

Various types of zinc oxide (ZnO) nanocrystais were synthesized by physical vaporization of zinc powders without the presence of catalysts and a subsequent exposure to air at a high temperature. These crystals were found to be composed of ZnO nanowires, sheets, and tetrapods. They were observed to crystallize as wurtzite ZnO single crystals. The nanowires are about 120 nm in diameter on average and up to a few dozens of micrometers in length, making aspect ratios higher than 10. The growth direction of the nanowires was identified to be the [001] direction of wurtzite ZnO structure. It was found from microscopic analyses that these ZnO nanowires can be highly flexible. The values for the thickness of ZnO sheets are scattered, averaging 100 nm. The tetrapods may have a different number of projections radiating from one central node.     

Organverteilungssysteme im Transplantationswesen aus ökonomischer Sicht

Zusammenfassung.   Auch nach dem Beschlu? des Gesetzgebers zugunsten einer sogenannten Informationsl?sung bleibt das Problem angemessener Vergabekriterien für die vorhandenen Organe, da diese Frage im neuen Organspendegesetz nicht abschlie?end gekl?rt ist. In dem Beitrag werden verschiedene Allokationsverfahren bezüglich ihrer gesellschaftlichen Akzeptanz und ?konomischen Effizienz beurteilt. Dazu werden medizinische Kriterien (z.B. HLA-Kompatibilt?t) und nicht-medizinsche Kriterien (z.B. Zahlungsbereitschaft des Spenders oder Zufall) anhand verschiedener allgemein akzeptierter Zielsetzungen (z.B. gleicher Zugang zu Gesundheitsleistungen oder geringe Kosten) abgewogen. Als innovative Form eines Organgewinnungssystemes wird die Clubl?sung vorgestellt, die den Spendern erlaubt, Pr?ferenzen bei der Verwendung der Organe zu realisieren. Scoringsysteme k?nnen darüber hinaus helfen, die Transparenz der Organverteilung zu erh?hen. Aus ?konomischer Sicht sind dabei vor allem medizinische Kriterien relativ zu nicht-medizinischen Merkmalen st?rker zu gewichten.      

A technique for regional analysis of femorotibial cartilage thickness based on quantitative magnetic resonance imaging

The objective of this work was to develop a methodology for measuring cartilage thickness in anatomically based subregions in the tibial and in the central weight-bearing femoral cartilage from magnetic resonance (MR) images. The tibial plateau was divided into a central area of the total subchondral bone area (tAB), and anterior, posterior, internal, and external subregions surrounding it. In the weight-bearing femoral condyles, central, internal, and external subregions were determined. The Euclidean distance between the tAB and cartilage surface was used for determining cartilage thickness. The reproducibility of the method was evaluated on test-retest data sets of 12 participants (six healthy, six with osteoarthritis). The subregion size was varied systematically to study the influence on the reproducibility. The size of the subregions was highly consistent under conditions of repositioning (standard deviation 0.0%-0.3%). The precision errors for regional mean cartilage thickness measurements ranged from 19 mum (1.5%) to 84 mum (4.7%). The computation of regional cartilage thickness values from segmented MR images is shown to be highly reproducible and robust under conditions of joint repositioning. In longitudinal studies, this technique may substantially enhance the ability of quantitative MRI to monitor structural changes in osteoarthritis at narrow time intervals.