Electrosynthesis and characterisation of poly(safranine T) electroactive polymer films

The phenazine safranine T has been electropolymerised by potential cycling at carbon film electrodes in nitrate-containing solutions at different pH: 2.0, 5.5, and 7.0, as well as from chloride solution, pH 5.5. The electroactive polymer obtained, poly(safranine T), has been analysed by cyclic voltammetry in different electrolyte solutions and its morphology examined using scanning electron microscopy. The surface coverage was calculated and found to be the highest for the film formed in chloride solution, pH 5.5, with 8.7 nmol cm^− 2. The other films had lower coverages, from 5.3 to 7.8 nmol cm^− 2, and are similar to those obtained for other phenazine dye polymers. Although the fastest polymerisation occurred in solutions at pH 5.5, the best electrochemical properties resulted from electropolymerisation at pH 2.0. Analysis of the cyclic voltammograms showed that in most cases the electrochemical processes at the polymer coated electrodes are limited by surface reactions. Scanning electron microscopy data confirmed the results obtained by cyclic voltammetry and showed that the most compact film was obtained in chloride solution.     

Effects of de-icing chemicals sodium chloride and potassium formate on cadmium solubility in a coarse mineral soil

Excessive use of sodium chloride (NaCl) as de-icing chemical causes environmental problems, such as elevated chloride concentrations in groundwater. On vulnerable sites, this can be avoided by using alternative organic de-icing chemicals, such as potassium formate (KHCOO). The environmental impacts of KCHOO are, however, not well known. This study reports the potential effects of NaCl and KCHOO on mechanisms controlling the mobility of cadmium (Cd) in roadside soils as a result of vehicular traffic. Changes in the solubility of Cd in a coarse mineral soil treated with these two de-icing chemicals were studied in a 50-day incubation experiment under four different moisture and temperature combinations and an initial soil Cd concentration of 3 mg kg(-1). After incubation, the distribution of soil Cd into different fractions was analyzed using a sequential extraction method. Soil pH and soil redox potential were recorded and the occurrence of Cd-Cl complexes in the soil was estimated using published stability constants. During incubation, KCHOO lowered the soil redox potential, but this was not accompanied by a decrease in the sorption capacity of oxides and the release of oxide-bound Cd into soil solution. On the other hand, elevated pH (from 4.3 to 6.7-8.5) in the formate treatments increased the sorption of Cd onto the oxide surfaces (up to 80% of total sorbed Cd). In the NaCl treatments, cation competition and formation of Cd-Cl complexes increased the water-soluble Cd fraction. Consequently, the amount of bioavailable Cd was 3.5 times smaller in the KCHOO than in the NaCl treatments.     

Possibilities for the utilisation of marine by‐products

Fish industry by‐products can account for up to 75% of the catch depending on postharvest or industrial preparation processes. Different terms such as ‘fish waste’, ‘by‐product’ and ‘rest raw materials’ have been used. The review gives an overview of value‐added processes that provide an alternative to low‐profit uses such as silage, fish meal and mince. The preparation of different by‐product fractions such as fish blood, marine lipids, omega‐3 fatty acids, fish protein fractions and bioactive components with nutraceutical potential, i.e. antioxidants and bioactive peptides, is considered. There are several future opportunities for the preparation of high‐value by‐products such as enzymes, minerals and other bioactive substances including hydroxyapatite, phosphorus, taurine and creatine. Both regulatory status and future market potential need to be considered. In addition, there is a need for technologies that maintain good quality by‐products and ‘simple’ processes to produce bulk products for further refining.     

Do claim factors predict health care utilization after transport accidents?

Background

Injured people who are involved in compensation processes have less recovery and less well-being compared to those not involved in claims settlement procedures. This study investigated whether claim factors, such as no-fault versus common law claims, the number of independent medical assessments, and legal disputes, predict health care utilization after transport accidents.

Method

The sample consisted of 68,911 claimants who lodged a compensation claim at the Transport Accident Commission (TAC) in Victoria, Australia, between 2000 and 2005. The main outcome measure was health care utilization, which was defined as the number of visits to health care providers (e.g. general practitioners, physiotherapists, psychologists) during the 5 year period post-accident.

Results

After correction for gender, age, role in accident, injury type, and severity of injury, it was found that independent medical assessments were associated with greater health care utilization (β = .36, p < .001). Involvement in common law claims and legal disputes were both significantly related to health care utilization (respectively β = .05, p < .001 and β = −.02, p < .001), however, the standardized betas were negligible, therefore the effect is not clinically relevant. A model including claim factors predicted the number of health care visits significantly better (ΔR² = .08, p < .001) than a model including only gender, age, role in accident, injury type, and severity of injury.

Conclusion

The positive association between the number of independent medical assessments and health care utilization after transport accidents may imply that numerous medical assessments have a negative effect on claimants’ health. However, further research is needed to determine a causal relationship.     

Synthesis and properties of oxetane monomers and oligomers with electro‐active pendent groups

BACKGROUND: Monomers and polymers carrying pendent electro‐active fragments are widely studied due to their application in various optoelectronic devices. Monomers containing triphenylamino, triphenyldiamino and carbazol‐9‐yl fragments with vinyl, epoxy or acryl functional groups are mostly used. The synthesized materials are used for preparation of hole transport layers as well as host materials for electrophosphorescent light‐emitting diodes. Much fewer presentations are reported on the preparation of monomers containing other electro‐active or functional groups. RESULTS: Here we describe oxetane monomers and their oligomers containing various electro‐active pendent groups. The weight‐average molecular weights of the oligomers are in the range 1420–3250 g mol^?1 with a molecular weight distribution of 1.7–4.1. The electron photoemission spectra of amorphous layers of the compounds established ionization potentials of 5.55–5.85 eV. Room temperature hole drift mobility in the layers of some oligomers exceeds 10^?7 cm² V^?1 s^?1 at high electric fields. CONCLUSION: The synthesized oligomers exhibit promising thermal and film‐forming properties. Amorphous layers of some of the materials demonstrate suitable ionization potentials and sufficient hole transport properties for their application in optoelectronic devices. Copyright © 2008 Society of Chemical Industry     

Structural and Optical Properties of Highly Nd-Doped Yttrium Aluminum Garnet Ceramics from Alkoxide and Glycolate Precursors

Yttrium aluminum garnet (YAG) nanopowders doped with high neodymium (Nd) content (3 at.%) were synthesized by the sol–gel processing of (i) alkoxide precursors and (ii) metal chelates formed by complexing the cations with polyethylene glycol. A stoichiometric YAG composition was obtained following both procedures; however, the agglomeration of particles was significantly higher in glycolate synthesis, which shielded residual organics from oxidation (elemental analyses). Distribution of Nd³⁺ ions in the YAG matrix, as shown by the absorption of pump energy and photoluminescence spectra of Nd:YAG ceramics, was more homogeneous in alkoxide-derived powders. The segregation of Nd centers in the glycolate-derived sample was supported by the precipitation of a crystalline Nd₂O₃ phase (X-ray diffraction) during sintering. High-resolution absorption spectra (⁴I_9/2(1)→⁴F_9/2(1)) of the powders showed that a higher absorption cross-section of glycolate-derived powders is due to Nd³⁺–Nd³⁺ ion pairing, which leads to the quenching of photoluminescence. Owing to the better dispersion of optically active centers, the photoluminescence signal was found to be substantially enhanced in alkoxide-derived Nd:YAG ceramics.     

Development of redox‐mediated oxysilane sol–gel biosensors on carbon‐film electrode substrates

Three types of carbon‐film electrodes, made from electrical resistors with 1.5‐, 15‐, and 140‐Ω nominal resistances, were used to develop redox‐mediated sol–gel biosensors, and the results were compared with those from previously investigated 2‐Ω carbon‐film electrodes. Two different redox mediators, copper hexacyanoferrate and poly(neutral red), were deposited onto the carbon‐film electrodes, with the latter showing good electrochemical properties for electroanalytical applications, which were best on electrodes made from 15‐Ω carbon‐film resistors. It was not possible to deposit mediator film on the carbon‐film resistor electrodes of 140‐Ω nominal resistance. Glucose oxidase was immobilized on poly(neutral red) modified electrodes with sol–gel encapsulation from a mixture of 3‐glycidoxypropyltrimethoxysilane and methyltrimethoxysilane precursors at a volume ratio of 2 : 1. The best sensor electrochemical properties and response to glucose in model solution were found with electrodes constructed from 15‐Ω resistors, although the stability under the same conditions was better in the biosensors constructed with 2‐Ω nominal resistance electrodes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

On Pseudo-Elastic Models for Stress Softening in Elastomeric Balloons

The phenomenon of stress softening observed in the cyclic inflation of spherical balloons or membranes is quantitatively and qualitatively examined. A new measure of the stress softening extent is proposed which correctly captures the main feature of this phenomenon. This measure of the stress softening is related to the relevant response functions in the constitutive models proposed in the literature to describe this effect. Using these relationships, the predictive capability of the theoretical models is examined. It is shown that only those theoretical models which admit a non-monotone character of the stress softening can properly describe this phenomenon.     

Phosphorus and nitrogen cycles in the vegetation of differently managed buffer zones

Vegetated buffer zones (BZs) between a cultivated field and a watercourse reduce erosion and load of particle-bound phosphorus (P), but decay of abundant vegetation increases the potential of BZs to act as a source of readily algal-available P. To quantify temporal variations in P and nitrogen (N) contents of the grassy vegetation of BZs on a clay soil (Vertic Cambisol) in south-western Finland, plant samples were collected six times between May 2005 and April 2006 from natural BZs, BZs grazed by cattle and BZs harvested by cutting and removal of the yield. The total dry weight biomass peaked in early August at 2,130–2,360 and 5,500–6,270 kg ha⁻¹ for the grazed and the other BZs, respectively. In August, 3,840–4,830 kg ha⁻¹ were removed from the harvested BZs while the entire biomass of the non-harvested BZs remained in the field. In October, total P and N contents varied from 2.4–10.2 to 19–72 kg ha⁻¹, respectively, the lowest amounts being for the young harvested BZ and the highest for the non-harvested BZs. A considerable decrease of P and N contents occurred in the biomass up to 6.1 and almost 30 kg ha⁻¹, respectively, after the first frosts. Harvesting of BZs is recommended to decrease the amount of P and N in the BZs and reduce the risk of P and N leaching outside the growing season.