bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian network models for environmental flow decision making in the Daly River, Northern Territory, Australia
Authors: Chan Terence U. , Hart Barry T. , Kennard Mark J. , Pusey Bradley J. , Shenton Will , Douglas Michael M. , Valentine Eric , Patel Sandeep
Published: September 2010

This paper reports the development and application of two Bayesian Network models to assist decision making on the environmental flows required to maintain the ecological health of the Daly River (Northern Territory, Australia). Currently, the Daly River is unregulated, with only a small volume of water extracted annually for agriculture. However, there is considerable pressure for further agricultural development in the catchment, particularly with demand for extra water extraction during the dry season (May–November).

The abundances of two fish species—barramundi (Lates calcarifer) and sooty grunter (Hephaestus fuliginosus)—were chosen as the ecological endpoints for the models, which linked dry season flows to key aspects of the biology of each species. Where available, data were used to define flow–fish habitat relationships, but most of the relationships were defined by expert opinion because of a lack of quantified ecological knowledge.

Recent field data on fish abundances were used to validate the models and gave prediction errors of 20–30%. The barramundi model indicated that the adult sub‐population was key to overall fish abundance, with this sub‐population particularly impacted by the timing of abstraction (early vs. late dry season). The sooty grunter model indicated that the juvenile sub‐population dominated the overall abundance and that this was primarily due to the amount of hydraulically suitable riffle habitat. If current extraction entitlements were fully utilized, the models showed there would be significant impacts on the populations of these two fish species, with the probability of unacceptable abundances increasing to 43% from 25% for sooty grunter and from 36% for barramundi under natural conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Using Rasch theory to guide the practice of survey development and survey data analysis in science education and to inform science reform efforts: An exemplar utilizing STEBI self‐efficacy data
Authors: Boone William J. , Townsend J. Scott , Staver John
Published: September 2010

Over many decades, science education researchers have developed, validated, and used a wide range of attitudinal instruments. Data from such instruments have been analyzed, results have been published, and public policies have been influenced. Unfortunately, most science education instruments are not developed using a guiding theoretical measurement framework. Moreover, ordinal‐level attitudinal data are routinely analyzed as if these data are equal interval, thereby violating requirements of parametric tests. This paper outlines how researchers can use Rasch analysis to develop higher quality science education instruments and why researchers must use Rasch analysis to prepare appropriate ordinal‐level data for parametric analyses. Detailed recommendations are set forth to help science education researchers increase the rigor of attitudinal instrument development and analysis. Suggestions are also set forth regarding how philosophical and analytical Rasch techniques align with broad goals of the science education research community. © 2010 Wiley Periodicals, Inc. Sci Ed 95:258–280, 2011
Neuronatin Promotes Neural Lineage in ESCs via Ca2+ Signaling
Authors: Lin Hsuan-Hwai , Bell Esther , Uwanogho Dafe , Perfect Leo W. , Noristani Harun , Bates Thomas J. D. , Snetkov Vladimir , Price Jack , Sun Yuh-Man
Published: September 2010

Neural induction is the first step in the formation of the vertebrate central nervous system. The emerging consensus of the mechanisms underling neural induction is the combined influences from inhibiting bone morphogenetic protein (BMP) signaling and activating fibroblast growth factor (FGF)/Erk signaling, which act extrinsically via either autocrine or paracrine fashions. However, do intrinsic forces (cues) exist and do they play decisive roles in neural induction? These questions remain to be answered. Here, we have identified a novel neural initiator, neuronatin (Nnat), which acts as an intrinsic factor to promote neural fate in mammals and Xenopus. ESCs lacking this intrinsic factor fail to undergo neural induction despite the inhibition of the BMP pathway. We show that Nnat initiates neural induction in ESCs through increasing intracellular Ca2+ ([Ca2+]i) by antagonizing Ca2+-ATPase isoform 2 (sarco/endoplasmic reticulum Ca2+-ATPase isoform 2) in the endoplasmic reticulum, which in turn increases the phosphorylation of Erk1/2 and inhibits the BMP4 pathway and leads to neural induction in conjunction with FGF/Erk pathway.
Antipsychotic‐induced DRD2 upregulation and its prevention by α‐lipoic acid in SH‐SY5Y Neuroblastoma cells
Authors: Deslauriers Jessica , Lefrançois Marilou , Larouche Annie , Sarret Philippe , Grignon Sylvain
Published: September 2010

Most antipsychotic (AP) drugs are dopamine (DA) D2 receptor (DRD2) antagonists and remain the main pharmacological treatment of schizophrenia. Long‐term AP use can give rise to tardive dyskinesia. It has been reported that chronic treatment with APs induces DRD2 upregulation and oxidative stress, which have been associated with tardive dyskinesia. We showed previously that H2O2‐induced oxidative stress increased DRD2 expression in human SH‐SY5Y neuroblastoma cells. We report here the effects of AP drugs on DRD2 expression levels in the same cell line and the effects of the inhibition of oxidative phenomena by (±)‐α‐lipoic acid treatment. Haloperidol, a first‐generation AP, induced an increase in DRD2 protein and mRNA levels, whereas amisulpride, a second‐generation AP, had no significant effect. (±)‐α‐Lipoic acid pretreatment reversed the haloperidol‐induced DRD2 upregulation in mRNA and protein levels. Furthermore, haloperidol induced a larger increase of oxidative stress biomarkers (protein carbonylation, lipid peroxidation, and superoxide anion production) than amisulpride. (±)‐α‐Lipoic acid also attenuated AP‐induced oxidative stress. Inhibition of catecholamine synthesis by α‐methyl‐DL‐tyrosine (AMPT) increased DRD2 expression and prevented further increase by APs. Our results suggest that haloperidol‐induced DRD2 upregulation is linked to oxidative stress and provide potential mechanisms by which (±)‐α‐lipoic acid can be considered as a therapeutic agent to prevent and treat side effects related to the use of first‐generation APs. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Rhodium‐catalyzed restructuring of carbon frameworks
Authors: Murakami Masahiro
Published: September 2010

Metal‐catalyzed reactions involving an elementary step which cleaves a carbon‐carbon bond provide unique organic transformations. Restructuring reactions recently developed in our laboratory, through which the carbon framework of a starting substance is restructured into a totally different carbon framework, are discussed, with the possibility of applying such methods to the synthesis of natural products. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 326–331; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000023
Dekontamination von Vakuumpumpen und Komponenten aus der Halbleiter‐ und Elektronikindustrie
Authors: Karges Jürgen , Lamprecht Robert , Schneider Hans‐Walter
Published: September 2010

Die Sicherheit der Mitarbeiter, der Umweltschutz und die Produktqualität: der reparierten Pumpen stehen im Mittelpunkt einer neuen Dekontaminierungsanlage für Vakuumpumpen und ‐komponenten aus den Halbleiterprozessen.

Die Dekontamination und Wartung dieser Vakuumpumpen ist mit erheblichen Risiken verbunden. Die sich in den Pumpen befindenden toxischen Substanzen dürfen unter keinen Umständen in die Umgebung abgegeben werden. Einmalig in Europa ist die hier beschriebene Dekontaminationsanlage in der Nähe Münchens. Verschiedene Spezialfirmen fertigten Vorrichtungen und Maschinen nach speziellen Erfordernissen.

Darüber hinaus wurden mit dem Hygiene‐Institut der Justus‐Liebig‐Universität in Giessen neue Wege der wissenschaftlichen und hygiene‐technischen Beratung von der Planung bis zur Abnahme der Anlage beschritten. Die Dekontaminierungsanlage mußte den strengen deutschen Umweltkriterien der Gewerbeaufsichtsämter und Umweltämter genügen.
Ausbau eines Sektormagnet‐RGA zu einem PC‐gestützten quantitativen Massenspektrometer
Authors: Solomon George M. , Schaefer Martin , Schaefer Klaus A.
Published: September 2010

Mit sorgfältiger Auslegung des Einlaßsystems und Eichung vor Ort werden Restgasanalysengeräte (RGAs) zu einem wichtigen Werkzeug für die quantitative Gasanalyse. Bisher denkt man bei RGAs in erster Linie an “billige und schmutzige” qualitative Geräte zur Lecksuche und/oder Nachweis von Verunreinigungen in Vakuumsystemen. In dieser Arbeit werden die Konstruktionsmerkmale für ein Einlaßsystem zu einem RGA diskutiert, wenn daraus ein quantitatives Massenspektrometer gemacht werden soll. Hierzu gehören schnelle Ansprechzeit ohne Entmischung der Probe, Eichstandards vor Ort, Vielfach‐Probeentnahmestellen und Fernbedienung. PC‐Steuerung für das Einlaßsystem und das RGA ergibt wichtige Eigenschaften wie automatisches Tunen der Peak‐Position, Dekonvolution der Spektren, Gemischanalyse basierend auf aktuellen Eichgasen, automatisches Ansteuern der Probenahmestelle in wahlweiser Reihenfolge und Datenspeicherung. Es werden Anwendungsbeispiele für solche integrierten Einlaßsysteme für industriellen und Forschungs‐Einsatz gegeben, wobei kontinuierliche Überwachung und automatische Eichung vorliegen.

Alle Massenspektrometer‐/RGA‐Einlaßsysteme beruhen auf den gleichen Subsystemen wie: Pumpstand mit Hochvakuumpumpe und Vorpumpe, das eigentliche Massenfilter mit dem Probenahmekopf, Steuerelektronik und Display, Einlaßventile und Durchflußbegrenzer, eventuell noch zusätzlich eine Probenahme‐Vorpumpe. Obwohl diese Bauteile sich im allgemeinen gleichen, werden oft kleine Einzelheiten des Einlaßsystems übersehen, so daß die einfacheren und damit billigeren Einlaßsysteme sich nicht für quantitative Gasanalysen eignen. Diese Arbeit beschäftigt sich vor allem mit diesen wichtigen Details, die bei der Auslegung eines Massenspektrometer‐Einlaßsystems zu beachten sind.
Vakuum bei der Destillation
Authors: Meili Albert
Published: September 2010

Destillationskolonnen werden in der Chemischen und Petrochemischen Industrie zur Trennung von Gemischen eingesetzt. Bei temperaturempfindlichen Produkten wird die Destillation unter Vakuum durchgeführt. Da die Trennfaktoren zwischen den einzelnen Komponenten mit fallendem Druck bei fast allen Produkten zunehmen, kann bei der Vakuumdestillation gleichzeitig Energie eingespart werden. An praktischen Beispielen werden die Vorteile gezeigt.
Lipophile Kronenverbindungen — selektive Extraktionsmittel für Metallionen; Syntheseprinzipien
Authors: Beger Jörg , Gloe Karsten
Published: September 2010

Lipophilic crown ethers are useful for metal ion extraction: they are soluble in organic phases and insoluble in aqueous ones. The lipophilicity can be enhanced by long‐chain hydrocarbon residues, by expanding the carbon content in the crown skeleton and by other structural variations.

The complexation behaviour and, therefore, the selectivity of crowns in extraction processes can be altered by changing the crown diameter, the kind and the number of hetero atoms within the crown ring or at positions outside the cycle. Furthermore, for the electro‐neutrality of the extracted species it is necessary to transfer also an anion into the organic phase. This problem can be solved with crown ether acids or with other hydrophobic inorganic or organic anions.

In this review with 276 references many synthetic routes and examples of such lipophilic crown ethers are described. Special attention is given to the building blocks for the crown ethers, which are important in the extraction area. So the survey should open a view for similar syntheses of new metal extraction reagents with coronand structure.
Reaktionen trivalenter Phosphorverbindungen mit tert‐Butoxylradikalen
Authors: Schwetlick Klaus , Pionteck Jürgen , König Thomas , Rüger Claus
Published: September 2010

The products of the reaction of several alkyl, aryl, sterically hindered aryl and cyclic phosphites, thiophosphites, benzenephosphonites and triphenylphosphine with tert‐butoxyl radicals generated by thermolysis of di‐tert‐butyl peroxalate (DTBPO) in chlorobenzene at 50°C was studied.

Alkyl phosphites are oxidized to the corresponding phosphates by β‐scission of the intermediate phosphoranyl radicals. Phenyl phosphites react under displacement of a phenoxyl to give tert‐butyl phosphites by α‐scission of the intermediate phosphoranyl radicals. Sterically hindered p‐methyl‐phenyl phosphites also form the tert‐butyl phosphites accompanied by rearranged p‐hydroxyphenylmethanephosphonates. Cyclic arylene phosphites are predominantly oxidized, substitution takes place to a minor extent.

Benzenephosphonites and phosphines react with tert‐butoxyl radicals by oxidation to give the corresponding phosphonates and phosphine oxide, resp.

Those phosphorus compounds which are oxidized with the formation of tert‐butyl radicals accelerate the thermal decomposition of DT BPO under the condition studied.
Metallclusterverbindungen  Chemie und Bedeutung Synthese, Struktur, Bindung
Authors: Walther Bernhard
Published: September 2010

The chemistry of metal cluster compounds has grown very rapidly during the last two decades mainly as a field of inorganic chemistry but other areas of chemistry too have made considerable contributions. More recently metal clusters have become of interest for different sciences, including physics, material sciences, biochemistry, and there is a strong search for practical applications. The article describes different synthetic strategies and methods for metal cluster compounds with metals in low oxidation states. The structure and bonding of low nuclearity clusters (M3 to M6) including their transformations in dependence of the electron count are discussed. There is a breakdown of the 18 electron rule observed for clusters containing six and more metal atoms and hence electron counting procedures like the Wade rules become helpful to predicting and remembering the structures of cluster compounds.
Über die Bestimmung von Spurenverunreinigungen in reiner Borsäure durch Extraktion‐Flammen‐AAS und Spektralphotometrie und über die Verwendung von White‐spirit als organisches Lösungsmittel in der Extraktion‐Flammen‐AAS
Authors: Arpadjan Sonja , Novkirischka Malina , Alexandrov Stojan , Petkov Plamen
Published: September 2010

The trace content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in boric acid is determined by flame AAS after extraction with DDTC/MIBK. The preconcentration efficiency is enhanced by dissolution of H3BO2 in NH4P or NaOH. The method permits the determination of 3 . 10−63 . 10−7 % of the elements with good precision and accuracy. The concentration of trace Cl− in H3BO3 is estimated by spectralphotometry with Hg(SCN)2. The applicability of white‐spirit as organic solvent in the extraction flame AAS is further discussed.
Funktionalisierung von makromolekularen organischen Verbindungen zur Einführung biologisch aktiver Gruppen
Authors: Hartmann Manfred , Klemm Dieter
Published: September 2010

Macromolecular organic compounds with biologically active groups have received increasing interest as drugs, herbicides and pesticides, disinfectants as well as technical biocides possessing novel properties. From the organic chemist's point of view, the synthesis of these modified polymers involves several attractive problems: search for suitable polymeric carriers, the design of the enzyme‐sensitive bond of the active agent and the optimum route of functionalization of synthetic or naturally occurring macromolecular materials. Of particular importance are biological and economic aspects derived from the special application, and any suggested solution must be checked in the same way.

This review surveys structural concepts and selected sythetic methods which are of general importance in the attachment of biologically active agents to macromolecules.
Thiolierungsreagenzien in der organischen Chemie
Authors: Viola Horst
Published: September 2010

Various reagents for thiolation generally available or easily accessible are reviewed and briefly characterized. A classification of the reagents with respect to the primary step of reaction enables synthetic chemists to select an appropriate reagent to produce definite products under mild and optimized conditions. There is a wide range of reagents of graduated reactivity for electrophilic thiolation.
Synthese von Brassinosteroiden
Authors: Adam Günter , Marquardt Volker
Published: September 2010

Since the discovery of brassinolide, the first member of a new class of steroidal plant growth regulators, the synthesis of such compounds has represented an area of tremendous activity. The synthetic pathways to the most important member brassinolide and other native brassinosteroids as well as to structural analogs including aza and thio compounds are reviewed. Besides the various methods for A/B ring functionalization especially the different principles for a stereoelective side‐chain construction, starting from 22‐aldehydes, Δ22‐sterols or pregnane derivatives as steroidal precursors, are discussed.
Methoden zur hierachischen Clusterung
Authors: Henrion André , Henrion René , Urban Petr , Henrion Günter
Published: September 2010

The methods of Pattern Recognition are a very powerful instrument for the arrangement and evaluation of inner relations of unknown subjects of investigation into groups of subjects which belong together as well as for the decision whether a priori unknown subjects belong to a priori known groups. Therefore these methods are useful for solving many chemical problems. After having published contributions about Principal Components, Non Linear Mapping and Non‐Hierarchical Clustering with CLUPOT here a complex BASIC‐program for the alternative application of the most important methods of hierarchical clustering like Single‐, Complete‐, Centroid‐, Average‐ (weighted and unweighted) Linkage, Ward's method and Flexible Strategy (according to Lance and Williams) is described which make it possible to choose the different distances (Euclid, Manhattan, Mahalanobis) and to find out the best approximation of method and subject of investigation. As a first example trace analytical results of different laboratories for different tungsten powders are compared.
Insertionsreaktionen mit Isocyanaten — Reaktionsmöglichkeiten, Kinetik, Mechanismen
Authors: Noack Rainer , Schwetlick Klaus
Published: September 2010

The insertion reactions of isocyanates into CN, CO, CS, SiN, SiO, SiS, SiP, PN, PO, PM, BC, BN, BO, BS, BHal, SnN, SnO, SnS and other MX bonds are reviewed. Rate constants are in the range of 10−6 to 103 M−1 s−1, often above 10 M−1 s−1. Reaction mechanisms freguently involve equilibria prior to the rate determining step. Cyclisations to N‐heterocycles, uretdiones and isocyanurates and formation of carbodiimides are observed as side‐reactions. Ring expansions open routes to macrocyclic compounds. Insertions are important in organometal catalysis of isocyanate reactions as well as in metal complex catalyzed syntheses and, therefore, in a number of industrial processes.
Thiocarbonsäureanhydride — eine neue Klasse von Thioacylierungsmitteln
Authors: Martin Arnim A. , Barnikow Günter
Published: September 2010

Thiocarboxylic anhydrides represent a new class of useful thioacylating reagents. For ten years they have increasingly been investigated whereas the application is limited because of their partly remarkable instability. The preparation is carried out by means of relatively simple reactions. From the beginning of our century first attempts to prepare thioanhydrides failed. Kato et al. first published the isolation and characterization of pure thiocarboxylic anhydrides in 1976.
Physikalisch‐chemische Verifikationsmöglichkeiten für ein C‐Waffen‐Verbot
Authors: Stöhr Ralf , Stock Thomas , Müller Konrad
Published: September 2010

The question of verification is one of the most intensively discussed problems for a chemical weapon convention at the Geneva Disarmament Conference. With the development and stockpiling of binary warfare agents in the USA the verification tasks reach a new dimension.

Sampling methods and analytical techniques are discussed for an efficient verification system for field tests and laboratory applications. Physicochemical techniques, e.g. enzymatic analysis, High Performance Liquid Chromatography, Gas Chromatography and their couplings with Mass Spectrometers or Fourier Transform‐Infrared Spectrometers are preferential techniques for central laboratories.
Poly(phenylenvinylen); Entwicklung eines elektroaktiven Polymermaterials vom unschmelzbaren Pulver zum transparenten Film
Authors: Hörhold Hans‐Heinrich , Helbig Manfred , Raabe Dietrich , Opfermann Johannes , Scherf Ullrich , Stockmann Regina , Weiß Dieter
Published: September 2010

The development of PPV systems has moved from intractable powders to flexible films. This opens new uses as thin film insulation material, as photoconductive electrophotographic recording material, and as novel electrochemical electrode material for polymer batteries. Tractable films were readily achieved either by transformation of a soluble precursor polymer or by introduction of solubilizing phenyl substituents. Contrary to wide‐spread expectations PPV is not a metal‐like conductor, but rather a broad‐band gap photoconductor (Eg= 2,4 eV). However, it can be made highly conducting upon appropriate chemical or electrochemical treatment, thus forming several salt‐like redox stages (σ = 10−4to 103S/cm). The formation of coexisting polymeric ion radicals (polarons) and diions (bipolarons) is well understood in terms of the concept of chain segment redox reactions (ECS concept). More detailed studies of the phenyl substituent effect show that the electronic properties are not altered drastically, but are modified due to broadening the band gap up to 2,9 eV along with an increase of the oxidation potential. Furthermore, phenyl substitution increases the resistance to heat, and stabilizes the deeply coloured redox stages.
Struktur, Eigenschaften und Anwendungen von Heteropolyverbindungen
Authors: Lunk Hans‐Joachim , Schönherr Siegfried
Published: September 2010

The present paper tries to give a survey of the field of heteropolyanion compounds the first of which were described as early as 1826 by Berzelius and of heteropolycation compounds which were prepared only recently. There is an obvious similarity between these two classes of compounds although the heteropolyanions are formed of transition metals of subgroups 6 and 5 (Mo, W, V, Nb, Ta) while in the heteropolycations the main group metal aluminium functions as the polyatom.

The introductory chapter presents a short historical survey; the following chapters describe synthetic methods, structural interrelationships and applications of these two classes of compounds. The coordination number of the heteroatom with respect to oxygen was chosen as the principle of classification of the heteropolyanions. This allows to show the close structural relations existing between anionic and cationic complexes.
AIBIIICVI2‐Halbleiter mit Chalcopyritstruktur
Authors: Kühn Günther , Neumann Hans
Published: September 2010

The ternary AIBIIICVI2chalcopyrite semiconductors are current of technological interest since they show promise for applications in such areas as solar cells and non‐linear optics. In this paper we give a survey about the crystal chemistry of this compounds including the structure of epitaxial layers and discuss some new results concerning their thermal properties. Furthermore the influence of the p‐d hybridization of the uppermost valence band on the band gap and the nature of the intrinsic defects in CuInSe2are considered.
Charakterisierung des σ‐Akzeptorverhaltens von modifizierten Polykieselsäuren
Authors: Spange Stefan , Hortschansky Peter , Ulbricht Antje , Heublein Günther
Published: September 2010

The acceptor properties of various modified poly silica acids as aerosil or suprasil have been investigated by means of complexation with Fe(phen)2(CN)2 in suspension of 1,2‐dichloroethane. U V‐measurements and the acceptor number (AN) of Gutmann fits a linear relation.

The influence of water on the surface acceptor strength in comparison to the behaviour in volume is discussed. Chlorination by SOCl2 drastically elevates the acceptor strength. Ester formation or reaction with poly epoxides lowers the AN of the surface.
Analytische Technik zur Quecksilberspurenbestimmung
Authors: Streufert Belief
Published: September 2010

The determination of mercury will be more and more important for environmental protection. The topic of this paper is the investigation of traces of mercury in water solutions and solid matters. It is entered in advantages and dis‐advantages of analytical methods applied to determination of traces of mercury. The flameless AAS (cold vapor method) is described as the most advantageous analytical method for investigations of one in water solutions. The graphical solutions of measuring results is presented and advices about systematic errors are also given.
Aus der Geschichte der physikalischen Chemie an Berliner Hochschulen während der Zeit der Berliner Physik
Authors: Bartel Hans‐Georg
Published: September 2010

The history of physical chemistry in Berlin during the period from 1870 to 1933 is reviewed. The Landwirtschaftliche Hochschule as well as the University of Berlin are playing a main role. The activities of H. Landolt, H. Jahn, J. H. van't Hoff, W. Nernst and M. Bodenstein in research and in lectureship are highlighted. Their works concerning optical activity, constancy of masses during chemical reactions, electrochemistry, thermodynamics, chemical kinetics and others are linked to the development of chemistry and physics. Landolt's and Nernst's aims to organize science and their relationship to the Physikalisch‐Technische Reichsanstalt are described. During the period mentioned above the physical chemistry in Berlin was part of the so‐called Berliner Physik.
Über die Azo‐Hydrazon‐Tautomerie
Authors: Mustroph Heinz
Published: September 2010

Since the azo‐hydrazone tautomerism was discovered, it has been the subject of much research and much heated debate. Only modern spectroscopic methods led to clear experimental evidences. Therefore, the first part of the review describes the spectroscopic methods (UV/VIS, IR, mass, NMR and X‐ray photoelectron spectra and crystal structure analysis) associated with a more detailed evaluation of the certainty of the results so obtained. It is shown that nuclear magnetic resonance (δH, δ13C, δ15N, δ14N, J15NH) is a generally applicable tool and it leads to the most reliable results. In the second part, a survey of the tautomerism of p‐hydroxyazo‐benzenes, phenylazonaphthols and the azocoupling products of pyrazolones and ß‐diketones is given. The effects of substituents, anellation and H‐bonding are summarized. The various assumptions, indications and evidences of tautomeric structures and solvent effects are discussed critically.
Über ternäre Komplexe des Eisen(III)‐Ions mit Aminopolycarbonsäuren und einigen Liganden
Authors: Koch Siegfried
Published: September 2010

In this paper is discussed the ternary complexation of iron(III) with aminopolycarboxylic acids (nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid) and some inorganic as well as organic ligands.

The complicated equilibria in aqueous solution were investigated by spectrophotometric and in some cases by electrophoretic methods. It was found that the composition of the species is Fe: APC:L = 1:1:1. The reaction mechanism of these equilibria is suggested and the stability of ternary complexes is described. The measured optical properties (λmax, ϵmax) of the mixed ligand complexes are discussed and compared with the corresponding binary species.
Strömungsenthalpimetrie
Authors: Berge Hans , Lammert Roland
Published: September 2010

Flow‐through enthalpimetric methods are efficient and cheap measuring techniques for laboratory and industry, but they are used only rarely. Possibilities and limits of using are discussed and proposals for construction are given.
Display‐Methoden bei der Mustererkennung
Authors: Henrion René , Henrion André , Henrion Günter
Published: September 2010

In addition to other methods of pattern recognition (for instance cluster analysis) display methods have much importance. They give the possibility of graphical representation of originally multidimensional data sets under different aspects. Some of the most important display methods like principal component analysis, linear discriminant display, nonlinear mapping and others are explained, compared with each other, discussed and illustrated in their relations. Data sets of analytical chemistry results are evaluated by BASIC programs for microcomputers and used for explanation of the possibilities and limits of the above mentioned methods.
Internationale und nationale Methoden der Verifikation regionaler und globaler Vereinbarungen zum Verbot chemischer Waffen
Authors: Lohs Karlheinz , Stock Thomas , Kläß Volker
Published: September 2010

Verification is the key issue in the ongoing Genevea talks on a comprehensive ban of all typs of chemical weapons, including the precursors of the binary warfare agents. To solve the still open questions regional steps as well as global proposals are under discussion. There are national and international control systems, techniques and methods useable. Automatic monitoring from the civil chemical industry and also the safeguards experience of the IAEA in Vienna can be examples to promote the treaty. Finding a general acceptable solution is very urgent, because otherwise a new spiral in the chemical arms race will be irresistible.
Struktur und Reaktivität von alternierenden Maleinsäure‐Anhydrid‐Copolymeren
Authors: Rätzsch Manfred , Steinert Volker
Published: September 2010

Alternating copolymers that contain maleic anhydride (MAn) as a component occur in two different stereochemical configurations which are differentiated by their reactivity. Model compounds, 2, 3‐dialkylsuccinic acids and their anhydrides, were investigated and it was demonstrated that there is a distinct difference between threo and erythro configurations in their chemical and physical behaviour. Both configurations also occur in the alternating copolymers.

The relative reactivity of the anhydride group compared to other carbon acid derivates and the mechanism of reaction to catalized and uncatalized nucleophiles are discussed. The reaction results of model compounds and of alternating MAn‐copolymers to aromatic and aliphatic amins are presented. The cyclization reaction to corresponding imides is described, and their dependence from the amine basicity and from steric effects of amine and its copolymers, produced without and with catalyzer, is outlined.
Zur Wechselwirkung von Stickstoff und Sauerstoff mit Adsorptionszentren in Zeolithen
Authors: Oehme Wolfgang , Meiler Wolfgang , Lochmann Jens Rainer , Siegel Hans
Published: September 2010

By use of adsorption measurements and 15N nmr studies could be shown that the adsorption of nitrogen in zeolites of type A and X is strongly influenced by the cations. The interaction increases in the sequence Na+ < Ca2+ < Mg2+. Whereas the interaction with Na+ and Mg2+ leads to chemical shifts of −2,5 and −9,5 ppm, respectively, the adsorption of nitrogen in a cation free zeolite shows no influence on the chemical shift with reference to free gas. Ab initio and semiempirical calculations support the results of the experiments. By extention of these calculations to oxygen the preference of nitrogen could be proved.
Lipophile Kronenverbindungen — selektive Extraktionsmittel für Metallionen
Authors: Gloe Karsten , Mühl Peter , Beger Jörg
Published: September 2010

Due to their pronounced complexing properties and selective solubilities lipophilic crown compounds can be used as effective extractants for metal ions. Structure modification of those compounds allows the directed influencing of complex‐forming tendency and extractability. In this review various aspects of extraction equilibria and the recent progress in the liquid‐liquid extraction of metal ions with crown compounds have been discussed. It is shown, that functionalized crown compounds give attractive possibilities in the winning, separation and concentration of metals. Especially promising are crown compounds with acid‐dissociable groups, because in this case a additional anion transfer during extraction of metal ions is not necessary. Further investigations in the field of synthesis and extraction of crown compounds can be expected with new fruitful and interesting results.
Lokalisierte versus delokalisierte Molekülorbitalbeschreibung Zusammenhänge — Strategien — Regeln
Authors: Soukup Rudolf Werner , Jameson Reginald F.
Published: September 2010

Highly localized and extensively delocalized representations of the molecular wavefunction are equivalent. If simple Lewis octet structures are zero order approximations of the localized valence molecular orbitals, the conventional MOs can be easily predicted using group theory. Valence state ionisation potentials in connection with the Sanderson concept of homonuclear binding energies are the basis for estimations of the orbital energies. The significance of such estimations is proven in some examples.
Natriumwasserglaslösungen — Aufbau, Eigenschaften und Probleme
Authors: Hoebbel Dagobert , Ebert Roland
Published: September 2010

The paper gives a review of more modern results of the 29Si n.m.r., chromatographic methods, molybdate and dye adsorption methods regarding the structure and characterization of technically important sodium water glass‐(sodium silicate‐solutions) with molar ratio SiO2/Na2O = 3–3,5. There are described the influence of molar ratio, SiO2 concentration, condensation degree, impurities and thermal treatment on the structure and properties respectively of sodium water glass (NaWG) solutions. The results show that the complicate structure of NaWG solutions and their influenceability by temperature, impurities, molar ratio and SiO2 concentration and furthermore the lack of suitable methods are reasons for the present insufficient characterization of NaWG solutions. It is shown that a more complete characterization especially regarding the thermal history of NaWG solutions is possible by combination of the molybdate method with the dye adsorption method. There is a hint of the existence of a thermal equilibrium state, which is influenced not only by the silicate anion distribution but the association equilibrium exused by concentration and state of distribution of impurities.
Anwendung “künstlicher Intelligenz”in der Chemie;Computersimulationen von Struktur‐Eigenschafts‐Beziehungen
Authors: Adler Bernhard , Dobers Sven , Eitner Bernd , Felgner Lutz , Mertsching Gudrun , Sorkau Eduard
Published: September 2010

The proceedings of chemical structure descriptors for structure‐activity studies is proposed. These descriptors are based on the set of properties distributed in a topological space (molecular graph). It dominates perceptions of empirical descriptors or of autocorrelation descriptors from physical properties of atoms, for instance, of electronegativities, polarisations or volumes of chemical groups. The choice between these different methods is determined by the type of interactions of chemical compound with the receptor. By means of pattern recognition techniques you can make a classification of molecules on the base of the activity features. As well we obtaine fuzzy results with 75–95% probabilities only
Metallclusterverbindungen — Chemie und Bedeutung;Cluster mit isolierten Hauptgruppenelementatomen, große Metallcluster, Clusterfluxionalität
Authors: Walther Bernhard
Published: September 2010

This part of the review on metal cluster compounds deals with clusters containing isolated main group element atoms, with high nuclearity clusters and metal cluster fluxionality. It will be obvious that main group element atoms strongly influences the geometry, stability and reactivity of the clusters. High nuclearity clusters are of interest in there own due to the diversity of the structures adopted, but their intermediate position between molecules and the metallic state makes them a fascinating research object too. These both sites of the metal cluster chemistry as well as the frequently observed ligand and core fluxionality are related to the cluster metal and surface analogy.
Multivariate statistische Bewertung von Ringversuchsdaten
Authors: Henrion Günter , Henrion René , Dietrich Thomas , Heininger Peter
Published: September 2010

As an example for evaluation of results of intercalibration and for valuation of laboratories the determination of Cr, Ni, Cd, Cu, Pb, Zn by 14 laboratories with flame AAS has been taken. The elements have been determined in synthetical solutions similar to river and to waste water. For the calculations BASIC computer programs have been used. Results for the single elements are compared with results for the six elements together. For this purpose displays of principal components, of nonlinear mapping and of linear discriminance analysis are suitable. NLM has some advantages, LDA important draw backs.
Ordungsfaktoren in der organischen Synthese Mustererkennung als Methode der Faktorenanalyse
Authors: Heimbach Paul , Bartik Tamas , Boese Roland , Schenkluhn Hartmut , Szczendzina Georg , Zeppenfeld Eva
Published: September 2010

In linear‐free‐energy relations and free‐energy relations substituents are characterized by so‐called “electronic” parameters, σ1‐parameters of substituents e. g. show direct correlations to Tolman's X1‐parameters or our P‐parameters. But by systematic variations at tetrahedral phosphorus we found a further set of Δ‐parameters, by which representative substituents like ‐OMe/‐SMe and ‐CMe3/‐SiMe3 with nearly identical Xi‐ or P‐parameters may be further characterized. The opposite influence of substituents on chemical behaviour is determined by the +/−sign of Δ‐parameters. By the signs of P‐and Δ‐parameters with triphenylphosphane as standard alternative order factors like DO/ACC, EVEN/ODD and S/AS may be identified. Compensation phenomena by selforganisation alone make LFE‐relations applicable. The importance of pattern recognition and consideration of absolute and relative control make general order control in chemical systems understandable (see next review).
Probleme toxikologischer Risikobeurteilung von Chemikalien
Authors: Pankow Dieter
Published: September 2010

Problems and difficulties in assessment of the toxicological risk of chemicals are reviewed. Evaluation is possible by means of acute and chronic toxicity studies including testing of carcinogenicity, mutagenicity, teratogenicity, behaviour, immune reactivity, and reproduction. The task of the industrial toxicologist is to establish dose‐effect relationships in order to set toxicity thresholds. Threshold limits are based on simple theory: Organism can tolerate some dosages of any chemical without adverse effect and conversely, almost any substance can cause adverse effects if sufficiently high dosages are given. Very toxic chemicals can be defined promptly, but to prove that a less‐obviously toxic substance could never do anything, to anybody, any time, is impossible. To minimize the residual risk safety factors for establishment of threshold limit values were used. Some economic aspects of the risk assessment of chemicals are discussed.
Untersuchungen an dealuminierten Pentasil‐Katalysatoren
Authors: Öhlmann Gerhard , Jerschkewitz Hans‐Oeorg , Lischke Günter , Parlitz Barbara , Richter Manfred , Eckelt Reinhard
Published: September 2010

Investigations of a ZSM‐5 type zeolite (HS 30, manufactured by VEB CK Bitterfeld without using any template) show that by dealumination various ratios of Si/Alframework can be achieved within a rather broad scale without structural changes of the initial substance. In any case the number of strong acid Brønsted centres of the elementary unit corresponds to the number of Al atoms contained therein.

Throughout all investigations the relative catalytic activity of the catalysts has been found to be in a linear relationship to the number of strong acid Brønsted centres (bridged OH groups). With the isomerisation of m‐xylene the initial non‐dealuminated sample already brings about a selectivity of ≈︁80% for the para‐isomere. No influence of dealumination on p‐selectivity could be observed.

With the conversion of methanol reduced catalytic activity of dealuminated samples results in an increase of the selectivity of lower olefins at the expense of aromatics for both reaction temperatures. The values obtained at 580°C are in favour of an additional formation of lower olefins due to the cracking of higher olefins. Dealumination gives also rise to an essential growth of the stability (i.e. possible integral charge by CH3OH) of the catalyst. With growing dealumination of the catalyst the attainable time on stream increases and reaches a maximum falling of thereafter.
Citric Acid — Its Natural and Synthetic Derivatives
Authors: Milewska Maria J.
Published: September 2010

Physico‐chemical and chemical properties of citric acid and methods of synthesis of its derivatives, namely esters, amides, 1,3‐dioxolan‐4‐ones etc. are presented. The important group of natural derivatives of this acid belonging to the siderophore family, i.e. compounds fulfilling in nature the function of biocarriers of ferric ions, is described in detail. The recent advances in the total synthesis of natural siderophores — citric acid derivatives, its homologues and analogues of the “retro” type are summarized.
Dithiocarbonsäuren und Dithiocarbonsäureester sowie Thiocarbonsäureamide aus methylenaktiven Chlormethylverbindungen und Schwefel
Authors: Thiel Wilfried , Mayer Roland , Viola Horst
Published: September 2010

The direct sulphurization of chloromethyl compounds with elemental sulphur leads to dithiocarboxylic acids, dithiocarboxylic esters or thioamides. In the presence of a base, the starting products can be oxidized by low‐temperature sulphurization, a reaction of wide application. The conversion of chloroacetic acid and its derivatives to thiooxalic derivatives, activated C2‐building blocks of growing interest in synthetic chemistry, is of special importance. As a rule, the examples described in the review have not been published. They show a new and easy way for the preparation of heterocycles containing activated dithiocarboxylic functions.
Thiophile Reaktionen an Thiocarbonylverbindungen und deren Redoxverhalten
Authors: Viola Horst , Hartenhauer Helge , Mayer Roland
Published: September 2010

The review describes thiophilic reactions of thiocarbonyl compounds with C‐ and S‐nucleophiles. They occur more frequently than has been supposed up to now, especially between vicinal thiocarbonyl systems and S‐nucleophiles. A general relation between thiophilic reactions and the redox behaviour of the system and a possibility to estimate approximately the thiophilic properties are discussed. Some conclusions for the synthesis and the behaviour of thiocarbonyl compounds are drawn.
Quantenchemische Beiträge zur Chemie der Kohlensäurederivate
Authors: Schädler Hans‐Dieter
Published: September 2010

Quantum chemical calculations are aible to clarify complex and concurrent mechanisms of the reaction of σ3‐carbonic acid derivatives. MNDO and ab initio calculations have been carried out on alternative transformation mechanisms. It has been shown that under certain circumstances the well believed elimination‐addition transformation is converted in an addition‐elimination manner. Now the kinetic stereoelectronic effect can explain the decomposition direction of the tetraedrical intermediat. Otherwise intermolecular proton transfer is the first step of elimination‐addition process instead of the sometimes formulated intramolecular [1, 3]‐Hydrogen rearrangement.
Mehrdimensionale Varianz‐ und Diskriminanzanalyse sowie Klassifizierungsmethoden zur Auswertung gaschromatographischer Ergebnisse
Authors: Henrion René , Henrion Günter , Michael Günter , Petereit Detlef
Published: September 2010

Multivariate data sets are a result of numerous methods of analytical chemistry, for instance like high performance chromatography. In addition to procedures of nonsupervised learning (e.g. cluster analysis) multidimensional analysis of variance, discriminant analysis and classification methods have extraordinary importance for data evaluation. Essential ideas of these methods are described and their application to two data examples by using the BASIC programs VARDIS and CLASS is illustrated. The first example deals with a discrimination of fuel filling stations being provided by the same source. In another example the recognition rate of 10 european brandies is studied. Both data sets were obtained by gas chromatography.
Cobaloxime als Katalysatoren
Authors: Madeja Kurt
Published: September 2010

Cobaloximes are discussed as catalysts generating highly reactive species like radicals in short catalytic cycles. This general reactivity pattern is demonstrated mainly by means of the reactions of these complexes with hydrogen. It is shown that adduct equilibria with the solvent affect the catalytic activity of these complexes, that their disadvantageous self hydrogenation can be suppressed at least partially and that organocobalt compounds are valuable intermediates for organic syntheses.
Fraktale in der physikalischen Chemie
Authors: Spindler Herbert , Vojta Günter
Published: September 2010

The fractal concept, created by Mandelbrot, has important consequences for the development of physical chemistry. Starting from the idea of the non‐integer Hausdorff dimension fractal mathematics is a powerful tool for the description of irregular structures and processes in physics and chemistry. The fractal dimension D is strictly only defined in the ranges of self‐similarity and normally does not fall below the embedding dimension by more than one. But smaller values of D are possible, too, if subsets of the fractal object are treated (subfractal dimension). Furthermore, a fractal model for porous solids is presented, and it is shown that the value of surface area for fractal objects is a function of measuring approach. The dynamics of atoms and molecules in solids and at surfaces can be described using the fracton dimension Ds < D. Diffusion in a fractal system generally proceeds more slowly than in a normal one. It is stated that percolation is governed by fractal geometry. The formation of many aggregates can be described in terms of fractal geometry. The fractal reaction dimension Dr may help to understand problems in reaction kinetics. For the discussion of dissipative structures and chaotic reactions, too, the fractal concept gains importance.
Quantitative Untersuchungen zur Adsorption von o‐Methylrot an modifizierten Polykieselsäureoberflächen
Authors: Erler Ulrich , Heublein Günther
Published: September 2010

Quantitative description of methyl‐red adsorption from benzene solution on surfaces of modified and unmodified silicas is possible with aid of adsorption isothermes of the Langmuir and the Freundlich‐type. Those investigations lead to conclusions about the degree of reaction between silica surfaces and modification reagents like silanes or active polymers.
Neuere Methoden zur quantitativen Auswertung von UV‐VIS‐Remissionsspektren
Authors: Gade Reinhold , Faßler Dieter
Published: September 2010

Based on a survey about the applications of diffuse reflectance spectroscopy various methods for quantitative evaluation of these spectra are presented. At first the correction of diffuse reflectance spectra of luminescent samples and the determination of pigment concentrations from reflectance data of powder mixtures are considered in detail. Furthermore a recently suggested method is described enabling the bulk‐absorption coefficients of substrate materials and the molar absorption coefficients of adsorbed molecules respectively to be calculated from diffuse reflectance spectra of powdered adsorbent‐adsorbates.