The synthesis of novel aliphatic bis(acenaphthelene) reactive monomers

Novel aliphatic‐bridged bis(acenaphthalene)s are synthesized and evaluated as potential precursors to high‐temperature reactive monomers. It was found that as the length of the aliphatic bridging unit increased, the thermal stability of bis(acenaphthalene) increased and melting point decreased. The use of an alternative route for the introduction of the reactive vinyl group resulted in a dramatic increase in monomer purity. The increase in monomer purity resulted in the creation of a processing window that enabled samples to be melt cast prior to polymerization, greatly improving their suitability as high‐temperature polymers. Polymerized samples were found to have high thermal stability, indicating they have potential as high temperature materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:5072–5082, 2005     

Theory on Morphological Instability in Driven Systems

Motivated by recent findings from simulation of a driven lattice gas under shifted periodic boundary conditions, we study within the context of a continuum model the interfacial stability of driven diffusive systems. In this model, an external driving field maintains the system away from equilibrium. Well below criticality, steady-state solutions of the associated bulk kinetic equation are obtained. Our results successfully account for the novel features found in simulation. In particular, the solution describing a pair of interfaces tilted with respect to the driving field under periodic boundary conditions shows a tilt-dependent bulk density (and internal energy), and boundary layers near one of the interfaces. Focusing on the interface dynamics, one finds that such an interface exhibits a characteristic Mullins-Sekerka instability. This is argued to be responsible for the onset of the single- to multistrip transformation observed in simulation.     

Pristinol,a Sesquiterpene Alcohol with an Unusual Skeleton from Streptomyces pristinaespiralis

A terpene cyclase from Streptomyces pristinaespiralis was characterized as the synthase for (+)‐(2S,3S,9R)‐pristinol. The structure of this sesquiterpene alcohol, which has a new carbon skeleton, was established by NMR spectroscopy and single‐wavelength anomalous‐dispersion X‐ray crystallography. Extensive isotopic labelling experiments were performed to distinguish between various possible cyclization mechanisms of the terpene cyclase and to decipher the EI‐MS fragmentation mechanism for pristinol.     

Noble Metal‐Iron Oxide Hybrid Nanomaterials: Emerging Applications

This account provides an overview of current research activities that focus on the synthesis and applications of nanomaterials from noble metal (e.g., Au, Ag, Pd) and iron oxide (Fe₃O₄) hybrids. An introduction to the synthetic strategies that have been developed for generating M–Fe₃O₄ nanomaterials with different novel structures is presented. Surface functionalization and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. The utilization of the advantageous properties of both noble metals and iron oxide for a variety of applications, such as theranostics, gene delivery, biosensing, cell sorting, bioseparation, and catalysis, is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. The fundamental requirements underpinning the effective preparation of M–Fe_xO_y hybrid nanomaterials shed light on the future development of heterogeneous catalysts, nanotheranostics, nanomedicines, and other chemical technologies.     

Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

The ⁹⁰YCl₃ radionuclide precursor (solution of ⁹⁰Y³⁺ in diluted HCl) of high purity and high specific activity is already commercially produced and successfully used in nuclear medicine. At the Nuclear Physics Institute ASCR, the ⁹⁰YCl₃ radionuclide precursor is prepared using extraction ⁹⁰Sr/⁹⁰Y generator (technology of centrifuge extractors with di-2-ethylhexylphosphoric acid, D2EHPA).¹ Its radionuclidic, radiochemical, and chemical purity were examined and specified. The procedure developed for labeling of DOTA-Tyr³-octreotide (DOTATOC) with carrier-free ^86/90Y by Rösch ² at the Institute of Nuclear Chemistry of the University Mainz was optimized and modified in our Department of Radiopharmaceuticals at NPI ASCR as standard labeling test (SLT) for analytical purposes. The SLT as a method for ⁹⁰YCl₃ radionuclide precursor quality control determining its labeling efficiency using ITLC SG chromatography is described and proposed thereinafter. The labeling-efficiency of the tested batches of our product reached more than 95%.     

Analyses of oxyanion materials by prompt gamma activation analysis

Prompt gamma activation analysis (PGAA) has been used to analyze metal ion oxyanion materials that have multiple applications, including medicine, materials, catalysts, and electronics. The significance for the need for accurate, highly sensitive analyses for the materials is discussed in the context of quality control of end products containing the parent element in each material. Applications of the analytical data for input to models and theoretical calculations related to the electronic and other properties of the materials are discussed.     

Remediation of Textile Dye Waste Water Using a White-Rot Fungus Bjerkandera adusta Through Solid-state Fermentation (SSF)

A strict screening strategy for microorganism selection was followed employing a number of white-rot fungi for the bioremediation of textile effluent, which was generated from one Ireland-based American textile industry. Finally, one fungus Bjerkandera adusta has been investigated in depth for its ability to simultaneously degrade and enrich the nutritional quality of highly coloured textile effluent-adsorbed barley husks through solid-state fermentation (SSF). Certain important parameters such as media requirements, moisture content, protein/biomass production and enzyme activities were examined in detail. A previously optimised method of dye desorption was employed to measure the extent of dye remediation through effluent decolorisation achieved as a result of fungal activity in SSF. B. adusta was capable of decolourising a considerable concentration of the synthetic dye effluent (up to 53%) with a moisture content of 80-85%. Protein enrichment of the fermented mass was achieved to the extent of 229 g/kg dry weight initial substrate used. Lignin peroxidase and laccase were found to be the two main enzymes produced during SSF of the dye-adsorbed lignocellulosic waste residue.     

Effect of spacer geometry on oxoanion binding by bis- and tetrakis-thiourea hosts

Hosts with thiourea groups bind anions by formation of multiple hydrogen bonds. This contribution discusses how spacers linking two or four thiourea groups affect the host affinity and selectivity. While most of the bis-thioureas bind H₂PO₄⁻ preferentially, the extent of selectivity over chloride, acetate, and H₂AsO₄⁻ is determined by the size of the binding cavity. A tetrakis-thiourea is shown to exhibit a unique H₂AsO₄⁻ selectivity, and the discrimination of chloride is enhanced by specific solvation in dimethyl sulfoxide.     

Defining the electronic and geometric structure of one-electron oxidized copper-bis-phenoxide complexes

The geometric and electronic structure of an oxidized Cu complex ([CuSal](+); Sal = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV-vis-NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal](+) (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal](+), affording exclusively a Cu(III) species in the solid state (4-300 K). Variable-temperature solution studies suggest that [CuSal](+) exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal(*)](+) (S = 1) and the high-valent metal form [Cu(III)Sal](+) (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine-bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSal(red)](+) (Sal(red) = N,N'-bis(3,5-di- tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)-ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu-bis-phenoxide complexes.