Specific ion effects on protein interfaces have been observed for many years, but yet comprehensive explanations regarding the mechanism by which ions interact with proteins and more general aqueous interfaces are still under investigation. Realistically, ion specificity on protein stability is due to numerous contributions and interactions between the solution and protein. However, the most important contribution is arguably the hydrophobic effect, specifically the change in free energy when water molecules are liberated from the interfacial region upon protein folding. In the work presented here, the effects of different ions on the critical micelle concentration (CMC) of 1, 2 –Hexanediol were examined to study salt effects on hydrophobicity by the means of fluorescence spectroscopy. Our results show that anions and cations do exhibit the specific effects on hydrophobic interactions. However, the origin of these specific ion effects different for cations and anions. Cation specific effects are caused by their ability to form cavities in solution, while anion specific effects arise from their ability to interact with the interface. These results are of interest to the researchers in the protein folding field, providing significant experimental hydrophobicity data necessary for theoretical biologists that are attempting to predict protein structures. / February 2015

The ability of dealginated seaweed, a waste material derived from the commercial processing of seaweed for alginate production, to remove cadmium, lead, nickel, copper, chromium, silver, aluminium and gold from solution was determined. Metal sorption was found to be rapid (90% removal within 5 minutes), achieving a residual concentration of 0.9 mg L[-1] after 1 h contact time from an initial solution concentration of 10 mg L[-1]. The binding of metal by dealginate was found to be pH dependent, optimal sorption occurring at around pH 6-8 for cadmium, lead, nickel, copper and chromium and pH 3-4 for aluminium and gold respectively, suggesting an ion exchange mechanism. Determination of a molar ratio in the displacement of calcium by cadmium on dealginate supported the presence of an ion-exchange relationship, since the displacement of approximately 1 mol of calcium by 1 mol of cadmium was observed. The sorption data was best fitted in the ion exchange approximation as opposed to the Langmuir model. The binding capacities were found to be 1.2, 0.5, 1.6, 0.8, 1.2, 0.4, 0.9 and 0.4 mmol g-1 for cadmium, lead, nickel, copper, chromium, silver, aluminium and gold respectively. The ion exchange constants were calculated to be 3.3 x 10[-6], 4.1 x 10[-6], 6.2 x 10[-6], 1.8 x 10[-6], 2.3 x 10[-6], 2.4 x 10[-7],8 x 10[-10] for cadmium, lead, nickel, copper, chromium, silver and aluminium. The values of the capacities and ion exchange constants showed affinity of the biosorbent to specific metals. The identification of the binding sites on the surface of dealginated seaweed was investigated by a number of techniques. Potentiometric titration revealed three distinct pKa values, the first having a similar value to carboxyl groups, the second being comparable with that of saturated thiols and amines and the third similar to sulphonate groups. Esterification of the dealginate resulted in the subsequent reduction in metal sorption, indicating that carboxyl groups are largely responsible for sorption except in the case of aluminium and gold, where 40-60% of the metal remained in solution after modification of the surface. Evidence of the FT-IR spectra confirmed the presence of carboxyl groups in untreated dealginate, while the number of carboxyl groups was markedly reduced in the esterified sample. The occurrence of other mechanisms apart from ion exchange was suggested by the FT-IR spectrum for aluminium and gold. ESEM images of the surface of dealginated seaweed showed the algae cell structure still present in large areas. X-ray maps revealed the presence of silver, aluminium and gold associated with sulphur atoms on the dealginate surface. EXAFS results showed that cadmium, lead, copper and silver were bound to the dealginate through oxygen atoms, possibly from carboxylate groups. Evidence of gold reduction from Au (III) to Au(l) and Au(O) was also confirmed by the bond distance calculated for this metal. Methods for the on-line preconcentration of cadmium, chromium, copper and lead and chemical speciation of Cr[3+] and CrO[4][2-] using a microcolumn packed with dealginated seaweed were developed. Effective column capacities were 4.0, 8.7, 9.4 and 8.5 mumol L[-1] for cadmium, chromium, copper and lead, respectively. The application of the method was extended to the determination of zinc, cobalt, mercury, scandium, strontium, vanadium, arsenic, selenium, manganese and antimony. The analytical procedures developed for metal preconcentration and chromium speciation were validated by analyses of two Lake Ontario reference materials, TMDA 51.2 and TMDA 54.2 and a synthetic seawater sample. The findings of this study demonstrated that the sorption of metal by dealginate is mainly due to an ion-exchange mechanism. The binding capacities of the biosorbent for the elements studied were adequate for trace analysis and the use of dealginate was shown to be a cheaper alternative to synthetic resins.

The thesis is concerned with some of the properties of positive and negative ions in liquid Helium, and in particular with the passage of ions, which are generated inside the liquid, through the free liquid surface into vapour. It was found, for negative ions, that this process was inhibited by an energy barrier, in agreement with other workers who have examined this problem, although there is considerable disagreement as to the magnitude of the barrier. It has been observed in the present work that the energy barrier depends upon the field, the position of the liquid surface in an ion cell, and the nature of the ion cell itself. The dependence of the barrier on these three parameters probably explains why diverse values for it have been reported. It was originally intended to use the ions as probes to examine dissipation mechanisms in the mobile superfluid Helium film. It had been reliably reported that ions preferentially travelled in the film. This was observed not to be the case however. The negative ion currents sin the film were found to be extremely small, when they existed at all, and no real positive ion currents in the film could be detected. This has been interpreted as being due to the combination of the large image potential binding the ion to the substrate, and the intrinsic roughness of the substrate. The present work has revealed that what appears at first sight to be a current of positive ions crossing the liquid surface can be attributed to a current of photoelectrons due to photoelectric emission from the surface of the collector. Such photoemission can arise from the uv radiation produced largely by ionic recombination in the region close to the a-emitting source. Screening the collector from the direct view of the a-source greatly reduced the photoelectron current. In order to extend the temperature range available, for the study of ion currents, a vortex refrigerator was designed and constructed. This enabled measurements to be extended down to 0.8K. Since there has been only one publication on the vortex refrigerator, which appeared during the building of the present one, its properties and operation with various design parameters were studied in detail.

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In this line by line commentary l have attempted to discuss all matters textual and linguistic on which a reader might resort to a commentary for aid. There is, naturally, a pronounced emphasis on textual criticism; literary comment is interwoven with my arguments as the play unfolds. I have endeavoured to cite Greek with sufficient generosity to enable the reader to form a different judgement from my own from the material I have furnished. Considerable space has also been devoted to matters mythological and religious, as the nature of the play demands. I conclude with an Endnote on the marginal annotations found in L. Three appendices follow: on the question of scenery, on alliteration in ancient poetry and poetic theory. and on a textual problem in the prologue to Euripides' Phrixus. As no new evidence has emerged either to enhance our knowledge of the paradosis or to indicate the date and general background of the play, I would prefer at this stage to direct the reader to A.S.Owen's introduction to his Clarendon edition of 1939 rather than burden this work further with a formal introduction. I conclude with a general bibliography of works often cited.