On perfect graded rings

We prove that a group graded ring with finite support is right perfect if and only if the identity graded component is right perfect.     

Ti-doped LiAlH4 for hydrogen storage: synthesis, catalyst loading and cycling performance

The direct synthesis of LiAlH(4) from commercially available LiH and Al powders in the presence of TiCl(3) and Me(2)O has been achieved for the first time. The effects of TiCl(3) loadings (Ti/Al = 0, 0.01, 0.05, 0.2, 0.5, 1.0 and 2.0%) and various other additives (TiCl(3)/Al(2)O(3), metallic Ti, Nb(2)O(5), and NbCl(5)) on the formation and stability of LiAlH(4) have been systematically investigated. The yield of LiAlH(4) initially increases, and then decreases, with increasing TiCl(3) loadings. LiH + Al → LiAlH(4) yields above 95% were obtained when the molar ratios of Ti/Al were 0.05 and 0.2%. In the presence of a very tiny amount of TiCl(3) (Ti/Al = 0.01%), LiAlH(4) is still generated, but the yield is lower. In the complete absence of TiCl(3), LiAlH(4) does not form. Addition of metallic Ti, Nb(2)O(5), and NbCl(5) to commercial LiH and Al does not result in the formation of LiAlH(4). Preliminary tests show that TiCl(3)-doped LiAlH(4) can be cycled, making it a suitable candidate for hydrogen storage.     

The discovery,synthesis and antimalarial evaluation of natural product-based polyamine alkaloids

Bioassay-guided fractionation of an antimalarial extract derived from the fungus Ramaria subaurantiaca afforded the known polyamine alkaloid, pistillarin. Nine pistillarin analogues were synthesised via EDC-mediated chemistry and these compounds along with the previously reported natural product polyamines, ianthelliformisamines A–C and spermatinamine, were evaluated against Plasmodium falciparum (3D7) parasites and a normal human cell line to determine parasite-specific activity. Spermatinamine (IC₅₀ 0.23 μM) and pistillarin (IC₅₀ 1.9 μM) were the two most potent antimalarials identified during these studies.     

Analysis of cyanobacterial toxins by physicochemical and biochemical methods

Cyanobacteria (blue-green algae) produce a wide range of low molecular weight metabolites that include potent neurotoxins, hepatotoxins, and cytotoxins. The accumulation of such toxins in freshwaters, and in brackish and marine waters presents hazards to human and animal health by a range of exposure routes. A review is presented of developments in the detection and analysis of cyanobacterial toxins, other than bioassays, including application of physicochemical, immunoassays, and enzyme-based methods. Analytical requirements are considered with reference to recently derived guideline levels for the protection of health and to the availability, or otherwise, of purified, quantitative cyanobacterial toxin standards.     

A co-Frobenius Hopf algebra with a separable Galois extension is finite

If is a co-Frobenius Hopf algebra over a field, having a Galois -object which is separable over , its ring of coinvariants, then is finite dimensional.

     

Synthesis of 2-C-Fluoromethyl-Myo-Inositol

Synthesis of 2-C-fluoromethyl-myo-inositol from DL-l-O-benzyl-2-oxiranyl-3, 4, 5, 6-tetra-O-benzyl-myo-inositol is described.     

Multi-elemental bio-imaging of rat tissue from a study investigating the bioavailability of bismuth from shotgun pellets

In recent years, bismuth has been promoted as a "green element" and is used as a substitute for the toxic lead in ammunition and other applications. However, the bioavailability and toxicity of bismuth is still not very well described. Following a hunting accident with bismuth-containing shots, a bioavailability study of bismuth from metal pellets inoculated into rat limb muscles was carried out. Bismuth could be found in urine and blood of the animals. Bio-imaging using laser ablation ICP-MS of thin sections of the tissue around the metal implant was carried out to find out more about the distribution of the metal diffusing into the tissue. Two laser ablation systems with different ablation cell designs were compared regarding their analytical performance. Low concentrations of bismuth showing a non-symmetrical pattern were detected in the tissue surrounding the metal implant. This was partly an artefact from cutting the thin sections but also bio-mobilisation of the metals of the implant could be seen. An accumulation of zinc around the implant was interpreted as a marker of inflammation. Challenges regarding sample preparation for laser ablation and bio-imaging of samples of diverse composition became apparent during the analysis.     

Sum-frequency spectroscopy of a monolayer of zinc arachidate at the solid-solid interface

Infrared-visible sum-frequency spectroscopy has been used to record the vibrational spectrum of a zinc arachidate monolayer at the interface between a sapphire prism and a fused silica lens. Spectra have been recorded for the monolayer deposited on the prism before, during, and after contact, and as a function of increasing pressure. Sum-frequency spectra are reported of the monolayer under sliding contact. The monolayer is found to be resistant to pressure- and shear-induced conformational disorder. However, frequency shifts, drops in peak intensities, and changes in peak intensity ratios have been observed as the monolayer is placed in contact between the prism and the lens. Transfer of monolayer material between the two surfaces is observed and is confirmed by spectra obtained with a monolayer deposited on the surface of the lens rather than the prism. On one face of the sapphire prism, the monolayer reconstructs to a low symmetry layer, probably due to epitaxy. The epitaxial structure disappeared in contact. Existing models for calculating sum-frequency spectra have been extended to include unit cells containing two molecules and torsion about the terminal C-C bond. This model can explain some, but not all, of the experimental observations.     

14‐Vertex Heteroboranes with 14 Skeletal Electron Pairs: An Experimental and Computational Study

Three isomers of [(Cp*Ru)₂C₂B₁₀H₁₂], the first examples of 14‐vertex heteroboranes containing 14‐skeletal electron pairs, have been synthesized by the direct electrophilic insertion of a {Cp*Ru⁺} fragment into the anion [4‐Cp*‐4,1,6‐RuC₂B₁₀H₁₂]^?. All three compounds have the same unique polyhedral structure having an approximate C_s symmetry and featuring a four‐atom trapezoidal face. X‐ray diffraction studies could confidently identify only one of the two cage C atoms in each structure. The other C atom position has been established by a combination of i) best fitting of computed and experimental ¹¹B and ¹H NMR chemical shifts, and ii) consideration of the lowest computed energy for series of isomers studied by DFT calculations. In all three isomers, one cage C atom occupies a degree‐4 vertex on the short parallel edge of the trapezium.