Skeleton-based canonical forms for non-rigid 3D shape retrieval

Computational Visual Media - The retrieval of non-rigid 3D shapes is an important task. A common technique is to simplify this problem to a rigid shape retrieval task by producing a...     

Preparation, structural characterisation and antibacterial properties of Ga-doped sol–gel phosphate-based glass

A sol–gel preparation of Ga-doped phosphate-based glass with potential application in antimicrobial devices has been developed. Samples of composition (CaO)_0.30(Na₂O)_0.20−x (Ga₂O₃) _x (P₂O₅)_0.50 where x = 0 and 0.03 were prepared, and the structure and properties of the gallium-doped sample compared with those of the sample containing no gallium. Analysis of the ³¹P MAS NMR data demonstrated that addition of gallium to the sol–gel reaction increases the connectivity of the phosphate network at the expense of hydroxyl groups. This premise is supported by the results of the elemental analysis, which showed that the gallium-free sample contains significantly more hydrogen and by FTIR spectroscopy, which revealed a higher concentration of –OH groups in that sample. Ga K-edge extended X-ray absorption fine structure and X-ray absorption near-edge structure data revealed that the gallium ions are coordinated by six oxygen atoms. In agreement with the X-ray absorption data, the high-energy XRD results also suggest that the Ga³⁺ ions are octahedrally coordinated with respect to oxygen. Antimicrobial studies demonstrated that the sample containing Ga³⁺ ions had significant activity against Staphylococcus aureus compared to the control.     

The pharmacokinetics of ephedrine after oral dosage in asthmatics receiving acute and chronic treatment

1 Ephedrine plasma levels have been measured in ten asthmatic patients given a singel dose of ephedrine hydrochloride (22 mg) along and in combination with theophylline and a barbiturate. 2 Pharmacokinetic assessment of the data indicated no significant intra-subject changes in kinetic parameters before or after chronic treatment with ephedrine HCl (11 mg three times a day) alone or in combination. 3 Tolerance to these therapeutic doses, if it occurs, is therefore not disposition-related but rather to pharmacodynamic changes.     

Effects of iron-tetrasulfophthalocyanine on the catalytic activities of Pt/C,PtRu/C,and Pd/C catalysts in a multi-anode direct formic acid fuel cell

This paper reports a systematic study of the effects of a promoter, iron-tetrasulfophthalocyanine (FeTSPc), on the catalytic activities of carbon supported Pt, PtRu, and Pd catalysts (Pt/C, PtRu/C, and Pd/C) for formic acid oxidation. A multi-anode direct formic acid fuel cell (DFAFC) was used to compare the effects on each catalyst of adding FeTSPc to the fuel stream. The FeTSPc significantly enhanced the activity of the Pt/C catalyst, but had little effect on the PtRu/C catalyst. The activity of the Pd/C catalyst was inhibited by the FeTSPc. A FeTSPc modified Pt/C was also evaluated in a conventional 5 cm² DFAFC.     

New a.d. convertor with special application to medium precision platinum resistance thermometry

Platinum resistance thermometers mounted on ceramic formers have a potential uncertainty, after calibration, of 0.01°C over a range exceeding ?30 to +250°C. To achieve this requires resistance measurements of higher precision than is conveniently available from commercial digital instruments. A new time-interval type of a.d. convertor has been developed for this purpose and incorporated in a simple digital resistance meter with a full scale reading of 300.000 ? and an uncertainty of 1 m?.     

Stability of wedge and channel flow of highly viscous and elastic liquids

Experiments are reported on the flow of a highly elasticoviscous polymer solution into a slit, in which instability was observed. This instability was manifest as an irregularity in the output along the slit and as an unsteadiness in the extentional flow into the slit. The onset of irregular flow was well-defined, and its intensity increased with flow rate. Similar results were noted for axial flow into a tube. Simplified linearized stability analyses bearing on the observed flow are given briefly in Appendixes 2 and 3. It is concluded that existing theories are inadequate to explain the observed phenomena.     

Structural Characteristics of Antibacterial Bioresorbable Phosphate Glass

Neutron diffraction with isotopic substitution has been used to probe the local environment of silver in a melt‐quench derived bioresorbable phosphate glass. Samples enriched with ¹⁰⁷Ag and ¹⁰⁹Ag were prepared and neutron diffraction data collected. A first‐order difference was taken between the data sets to give detailed information about the silver environment in the glass matrix. The measured Ag‐O correlation has three components in the first coordination shell at 2.28 Å, 2.51 Å, and 2.58 Å with coordination numbers of 2.1, 2.7, and 1.1, respectively, consistent with silver occupying a distorted octahedral environment. These results have been correlated with those from Ag K‐edge X‐ray absorption near‐edge spectroscopy measurements. The results suggest that the addition of silver to the (CaO)_0.3(Na₂O)_0.2(P₂O₅)_0.5 system has a significant effect on the host phosphate network, with shorter and more branched chains replacing the long chains and rings normally associated with the metaphosphate composition.     

Antimicrobial Gallium‐Doped Phosphate‐Based Glasses

Novel quaternary gallium‐doped phosphate‐based glasses (1, 3, and 5 mol % Ga₂O₃) were synthesized using a conventional melt quenching technique. The bactericidal activities of the glasses were tested against both Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive (Staphylococcus aureus, methicillin‐resistant Staphylococcus aureus, and Clostridium difficile) bacteria. Results of the solubility and ion release studies showed that these glass systems are unique for controlled delivery of Ga³⁺. ⁷¹Ga NMR measurements showed that the gallium is mostly octahedrally coordinated by oxygen atoms, whilst FTIR spectroscopy provided evidence for the presence of a small proportion of tetrahedral gallium in the samples with the highest gallium content. FTIR and Raman spectra also afford an insight into the correlation between the structure and the observed dissolution behavior via an understanding of the atomic‐scale network bonding characteristics. The results confirmed that the net bactericidal effect was due to Ga³⁺, and a concentration as low as 1 mol % Ga₂O₃ was sufficient to mount a potent antibacterial effect. The dearth of new antibiotics in development makes Ga³⁺ a potentially promising new therapeutic agent for pathogenic bacteria including MRSA and C. difficile.     

Carbon supported PtBi catalysts for direct formic acid fuel cells

Carbon supported PtBi bimetallic catalysts (PtBi/C) prepared by depositing Bi on a commercial Pt/C catalyst and by codeposition of Pt and Bi have been compared for formic acid oxidation in a multi-anode direct formic acid fuel cell. Both types of catalyst gave much higher cell performances than the Pt/C, with only low amounts of Bi (Pt to Bi mole ratios of 11:1 and 14:1, respectively) required for optimum performance. The high Pt to Bi ratio for the best codeposited catalyst indicates that the Bi was concentrated at the surface, and this is consistent with X-ray diffraction and X-ray photoelectron spectroscopy results. However, cyclic voltammetry revealed a strong electronic effect that is inconsistent with surface decoration. The effects of the Bi have been attributed to selective blocking of sites at which CO is formed.