The care of chronic wounds carries a heavy financial burden on the healthcare industry, with billons being spent annually on their treatment. This, coupled with a decreased quality of life for sufferers, has led to a real urgency in developing inexpensive wound dressings that promote wound healing. Alginate gels for application as wound dressings were formed by varying alginate (0%-6% w/v), calcium carbonate (0%-1% w/v), hydrogen peroxide (0%-3.75% v/v), and hyaluronic acid (0-1.25 mg/L) content. The aging effects on the physical properties of the gels over a 14-day period were also investigated. The results indicated that the concentration of calcium carbonate and hydrogen peroxide, as well as sample age, all had a significant effect on the rupture characteristics and gelation time of the gels. Increased calcium carbonate content caused an increase in rupture force and rupture energy values, whereas increased hydrogen peroxide content and sample age resulted in a decrease in rupture force and rupture energy measurements. Increased calcium carbonate and hydrogen peroxide content produced a decrease in the time required for gel formation. Statistical models were also produced to provide a means of estimating rupture characteristics and gelation times for gels containing other concentrations of these components.
The conductivities of single crystals of copper formate tetrahydrate (CFT) have been determined along the three principal crystallographic axes with proton-injecting electrodes. The ohmic conductivities at 298 K are : 5.5 k 1.6 x lo-' Q-' cm-l (along the b-axis), 8.5 k2.1 x lo-* R-' cm-' (along the a-axis) and 7 & 2 x !X1 cm-' (along the c axis). Since the H-bonded network lies in the ab-plane, the observed anisotropy of conduction suggests protonic conductivity. The Arrhenius plot of u exhibits a change of slope and a transition to a lower conductivity at the paraelectric -+ antiferroelectric phase change (235 K). The energies of activation for conduction within the ab-plane are 0.56 eV above 235 K and 0.65 eV below 235 K. The tetradeuterate has an ohmic conductivity approximately an order of magnitude lower than the tetrahydrate (within the ab-plane). Space-charge-limited currents are observed at high fields.The CFT crystals behave as semipermeable membranes to protons and this supports the view that protons axe mobile within CFT. If conduction is indeed protonic, CFT is a very ready hydrate protonic conductor exhibiting a conduction greater than ice.
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