6.1.2. Aqueous V(III) Chemistry 877 6.1.3. Oxidation State of Vanadium in Tunicates 878 6.1.4. Uptake of Vanadate into Tunicates 879 6.1.5. Vanadium Binding Proteins: Vanabins 879 6.1.6. Model Complexes and Their Chemistry 880 6.1.7. Catechol-Based Model Chemistry 880 6.1.8. Vanadium Sulfate Complexes 881 6.2. Fan Worm Pseudopotamilla occelata 883 7. Vanadium Nitrogenase 883 7.1. Nitrogenases 883 7.2. Biochemistry of Nitrogenase 884 7.3. Clusters in Nitrogenase and Model Systems: Structure and Reactivity 885

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The chemistry and biochemistry of vanadium and the biological activities exerted by vanadium compounds.

Starting with the history of the fundamental science of the relation of structure to composition delineated completely by Goldschmidt, we use the perovskite structure to illustrate the enormous pow...

The perovskite structure—a review of its role in ceramic science and technology

Calcium oxalate (CaOx) crystals are distributed among all taxonomic levels of photosynthetic organisms from small algae to angiosperms and giant gymnosperms. Accumulation of crystals by these organisms can be substantial. Major functions of CaOx crystal formation in plants include high-capacity calcium (Ca) regulation and protection against herbivory. Ultrastructural and developmental analyses have demonstrated that this biomineralization process is not a simple random physical-chemical precipitation of endogenously synthesized oxalic acid and environmentally derived Ca. Instead, crystals are formed in specific shapes and sizes. Genetic regulation of CaOx formation is indicated by constancy of crystal morphology within species, cell specialization, and the remarkable coordination of crystal growth and cell expansion. Using a variety of approaches, researchers have begun to unravel the exquisite control mechanisms exerted by cells specialized for CaOx formation that include the machinery for uptake and accumulation of Ca, oxalic acid biosynthetic pathways, and regulation of crystal growth.

CALCIUM OXALATE IN PLANTS: Formation and Function

I. Introduction A FUNCTIONAL relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century. In the case of bone, as observed with other cells and tissue, the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling. For many years, bone was defined anatomically and examined largely in a descriptive manner by ultrastructural analysis and by biochemical and histochemical methods. These studies provided the basis for our understanding of bone tissue organization and orchestration of the progressive recruitment, proliferation, and differentiation of the various cellular components of bone tissue. Now, complemented by an increased knowledge of molecular mechanisms that are associated with and regulate expression of genes encoding phenotypic compone...

Molecular mechanism mediating proliferation, defferentiation interralationships during progressie development of the osteoblast phenotype

Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.

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Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

The preparation and properties of new complexes containing the biometals Fe(III), Co(II) and Ni(II) coordinated to the anti-inflammatory drug Suprofen are reported. The elemental analyses, together with the magnetic and thermal behavior and electronic, IR and Raman spectra, indicated the following stoichiometries for the latter two complexes: [M(Sup)2(H2O)4]. For the Fe(III) complex, the generation of a dinuclear species may be proposed on the basis of 57Fe Mossbauer measurements.

REPARATION AND CHARACTERIZATION OF NEW SUPROFEN COMPLEXES OF Fe(III), Co(II) AND Ni(II)

Das IR-Spektrum von Te2O4 · HNO3 (sog. „basisches Tellurnitrat”) wurde an Hand der bekannten Kristallstruktur zugeordnet und diskutiert. Einige Aspekte des thermischen Verhaltens der Verbindung wurden an Hand von DTA-, IR- und rontgenographischen Messungen geklart.



I.R. Spectrum and Thermal Behaviour of Te2O4 · HNO3



An assignment of the infrared spectrum of Te2O4 · HNO3 (“basic tellurium nitrate”) based on the known crystal structure is proposed and discussed. Some aspects of the thermal behaviour of the compound were clarified by means of DTA, IR, and X-ray measurements.

IR‐Spektrum und thermisches Verhalten von Te2O4 · HNO3

Enrique J. Barana, Oscar E. Pirob, and Juan Zinczukc a Centro de Quimica Inorganica (CEQUINOR, CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. Correo 962, 1900 La Plata, Argentina b Departamento de Fisica and Instituto IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata, Argentina c Instituto de Quimica Organica de Sintesis (IQUIOS/CONICET, UNR), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina

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A new supramolecular assembly obtained by reaction between thiosaccharin and hexamethylenediamine

The Raman spectra of microcrystalline powders of Ag2C2O4, Tl2C2O4 and HgC2O4 are recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of other previously investigated metallic oxalates. In the case of Tl2C2O4 also IR data were used to complement the spectral analysis.

Raman spectra of some heavy metal oxalates

The title compounds are prepared by solid state reactions of stoichiometric mixtures of Ln2O3, Fe2O3, and TeO2 (Pt crucibles, 1000 °C, 2 h).

Enrique J. Baran

Papers

REPARATION AND CHARACTERIZATION OF NEW SUPROFEN COMPLEXES OF Fe(III), Co(II) AND Ni(II)

IR‐Spektrum und thermisches Verhalten von Te2O4 · HNO3

A new supramolecular assembly obtained by reaction between thiosaccharin and hexamethylenediamine

Raman spectra of some heavy metal oxalates

Crystallographic and Spectroscopic Characterization of LnFeTeO6 (Ln: La, Pr, Nd, Sm) Materials.