Proton conducting membranes are a key component in fuel cell designs. Properties like proton conductivity, water uptake, ion exchange capacity and physiochemical stability dictate the performance and longevity of the complete fuel cell system. Designing a proton conductiting membrane takes several factors, such as monomer choice and their respective functionalization into account. Besides that, economically favourable reactions as well as environmental compability have to be considered. This work demonstrates the development of a fuel cell membrane material starting from broadly available, cost-efficient educts. Few reaction steps, also including cost-efficient reagents, have been employed in order to obtain a doubly sulfonated monomer based on naphthalene-1,5-disulfonic acid (Armstrong´s acid) suitable for polymerizations. Suzuki polycondensation of the given monomer partly yielded processable films for further investigation. A cost-efficient, atom-economic deprotection stategy was developed for sulfonated polyphenylenes, yielding proton conducting membranes. Further modification of the backbone structure, by incorporating an excess of hydrophobic meta,meta,meta-terphenylene units, led towards balanced properties of the material. The impact of polymer constitution, was investigated and discussed via the implementation of para,meta,para-substituted instead of meta,meta,meta-substituted terphenylene. Alternating and statistical copolymers including para,meta,para-substituted terphenylene were developed and investigated. The reported proton conducting membranes pose suitable and promising candidates for fuel cell applications.

Proteins and their intricate network of interactions are fundamental to many molecular processes that govern life. Mass spectrometry-based structural proteomics represents a powerful set of techniques for characterizing protein structures and interactions. The last decade has witnessed a large-scale adoption in the application of these techniques toward solving a variety of biological questions. Addressing these questions has often been coincident with the further development of these techniques. Insight into the structures of individual proteins and their interactions with other proteins in a proteome-wide context has been made possible by recent developments in the relatively new field of chemical crosslinking combined with mass spectrometry. In these experiments crosslinking reagents are used to capture protein-protein interactions by forming covalent linkages between proximal amino acid residues. The crosslinked proteins are then enzymatically digested into peptides, and the covalently-coupled crosslinked peptides are identified by mass spectrometry. These identified crosslinked peptides thus provide evidence of interacting regions within or between proteins. In this dissertation the development of tools and methods that facilitate this powerful technique are described. The primary arc of this work follows the development and application of mass spectrometry-based approaches for the identification of protein crosslinks ranging from those which exist endogenously to those which are introduced synthetically. Firstly, the development of a novel strategy for comprehensive determination of naturally occurring protein crosslinks in the form of disulfide bonds is described. Secondly, the application of crosslinking reagents to create synthetic crosslinks in proteins coupled with molecular dynamics simulations is explored in order to structurally characterize the intrinsically disordered tau protein. Thirdly, improvements to a crosslinking-mass spectrometry method for defining a protein-protein interactome in a complex sample is developed. Altogether, these described approaches represent a toolset to allow researchers to access information about protein structure and interactions. / Graduate

The study was an assessment to determine the health rehabilitation interventions employed by Zimbabwe health actors between 2009 and 2011. It also was to ascertain the extent to which the interventions met criteria for effective rehabilitation, and that includes, health rehabilitation should ease the transition between health humanitarian and health development. Data was collected through interviewing health actors and review of policy documents while a vulnerability analysis approach was applied. The study revealed that, while the implemented health recovery interventions resulted in halting the health crisis, their role in facilitating progress towards health development was marginal. There were clear humanitarian residual issues and evidence of weak areas of the health system. A clear pathway needed to be mapped by actors, particularly policy makers to ensure effective rehabilitation. However, this seemed to lack in some areas. There were numerous overlapping and repetitive policies with little detailed guidelines. / Development Studies / M.A. (Development Studies)

This dissertation was carried out to try to understand the role of social capital in the migration of Zimbabwean migrants to Botswana. It describes elements and types of social capital Zimbabwean undocumented migrants used to come to Botswana. Questionnaires and in-depth interviews were used to obtain data from respondents. Though the influence of macro factors initially pushed migrants to migrate, there was evidence of the existence of social networks. Findings showed the use of social networks by Zimbabwean undocumented migrants. Though kinship networks were dominant in the initial migration stages there was a wane in the destination as migrants reverted to friendship networks for flexibility. Linking existed at both the place of origin and destination. Social control, channelling and negative social capital were discovered among migrants. Migrants developed mechanisms to counter the Botswana’s enforcement policy. / Sociology

Soft matter, here, liquids and polymers, have adaptability to a surrounding geometry. They intrinsically have advantageous characteristics from a mechanical perspective, such as flowing and wetting on surrounding surfaces, giving compliant, conformal and deformable behavior. From the behavior of soft matter for heterogeneous surfaces, compliant structures can be engineered as embedded liquid microstructures or patterned liquid microsystems for emerging compliant microsystems. Recently, skin electronics and soft robotics have been initiated as potential applications that can provide soft interfaces and interactions for a human-machine interface. To meet the design parameters, developing soft material engineering aimed at tuning material properties and smart processing techniques proper to them are to be highly encouraged. As promising candidates, Ga-based liquid alloys and silicone-based elastomers have been widely applied to proof-of-concept compliant structures. In this thesis, the liquid alloy was employed as a soft and stretchable electrical and thermal conductor (resistor), interconnect and filler in an elastomer structure. Printing-based liquid alloy patterning techniques have been developed with a batch-type, parallel processing scheme. As a simple solution, tape transfer masking was combined with a liquid alloy spraying technique, which provides robust processability. Silicone elastomers could be tunable for multi-functional building blocks by liquid or liquid-like soft solid inclusions. The liquid alloy and a polymer additive were introduced to the silicone elastomer by a simple mixing process. Heterogeneous material microstructures in elastomer networks successfully changed mechanical, thermal and surface properties. To realize a compliant microsystem, these ideas have in practice been useful in designing and fabricating soft and stretchable systems. Many different designs of the microsystems have been fabricated with the developed techniques and materials, and successfully evaluated under dynamic conditions. The compliant microsystems work as basic components to build up a whole system with soft materials and a processing technology for our emerging society.

The study was an assessment to determine the health rehabilitation interventions employed by Zimbabwe health actors between 2009 and 2011. It also was to ascertain the extent to which the interventions met criteria for effective rehabilitation, and that includes, health rehabilitation should ease the transition between health humanitarian and health development. Data was collected through interviewing health actors and review of policy documents while a vulnerability analysis approach was applied. The study revealed that, while the implemented health recovery interventions resulted in halting the health crisis, their role in facilitating progress towards health development was marginal. There were clear humanitarian residual issues and evidence of weak areas of the health system. A clear pathway needed to be mapped by actors, particularly policy makers to ensure effective rehabilitation. However, this seemed to lack in some areas. There were numerous overlapping and repetitive policies with little detailed guidelines. / Development Studies / M.A. (Development Studies)

Mit Lösungen von 9,10-Diphenylanthracen und N(C2H5)4ClO4 oder N(C4H9)4ClO4 als Leitsalz im Lösungsmittel Acetonitril wurden Elektrochemilumineszenz (ECL)-Experimente durchgeführt. Dazu wurden die Elektroden mit Folgen von jeweils drei in bestimmten zeitlichen Abständen aufeinander folgenden Potentialsprüngen polarisiert. Es wird gezeigt, dass bei entsprechender Wahl der Potentiale und der Haltezeiten anodische und kathodische ECL-Emissionen gleicher Intensität erzeugt werden können. Sodann wurde ECL in den Derivaten von Poly(p-phenylen-vinylen), MEH-PPV und DB-PPV erzeugt. Diese leitfähigen Polymere wurden als dünne Schichten auf Platin-Elektroden aufgebracht und wie bei ECL aus der Lösungsphase in Acetonitril-Elektrolyten mit Tetralkylammonium-Leitsalzen Potentialsprüngen unterworfen. Bei geeigneter Einstellung der Potentialsprünge und Haltezeiten konnten anodische und kathodische ECL gleicher Intensität erhalten werden. Dies ist das erste Mal, dass symmetrische ECL mit polymerbeschichteten Elektroden erhalten wurde. Die Kinetik der ECL weicht deutlich von der aus der Lösungsphase ab. Der ECL-Prozess verläuft langsamer als in der Lösungsphase, und der Leitelektrolyt hat einen signifikanten Einfluss auf das elektrochemische Verhalten der Polymerschicht. Die Ursachen dafür wurden über Modellrechnungen analysiert, mit denen die Ladungstransportprozesse in der Polymerschicht simuliert wurden. In derartigen Simulationsrechnungen konnten die Geschwindigkeitskonstanten der ECL-Reaktion sowohl im Polymer als auch in der Lösung bestimmt werden. Um die Stabilität der Polymerschichten zu erhöhen, wurde versucht, die Polymerketten mit Synchrotronstrahlung zu vernetzen. Diese Experimente brachten nicht das erwartete Ergebnis. Die Ursachen dafür werden auf der Grundlage von Ex-Situ-Raman-spektroskopischen Untersuchungen diskutiert. / Electrochemiluminescence (ECL) has been generated in solution phase using 9,10-diphenylanthracene (DPA) with TEAClO4 (or TBAClO4) in acetonitrile solvent. Triple potential step was used for the generation of ECL. It was found that anodic and cathodic ECL of equal intensities can be generated by proper choice of potential step magnitude, width and the waiting period (tw) between successive triple potential steps. ECL was then generated in conducting polymers poly(2-ethylhexyloxy-5-methoxy-1,4-phenylenevinylene) (MEH-PPV) and poly(2,3-dibutoxy-1,4-phenylenevinylene) (DB-PPV) by coating them on Pt electrodes and subjecting to potential steps in tetraalkylammonium salt solutions with acetonitrile. Similar to the case of solution phase ECL, symmetrical anodic and cathodic ECL could be observed by the appropriate choice of the potential step parameters. But the kinetics of the ECL was found to be different from that of the solution phase ECL. The time scale of the ECL process was found to be longer than that in the solution phase ECL. The nature of supporting electrolyte had a remarkable impact on the electrochemistry of conducting polymers. The reasons were analyzed by theoretical calculations evoking the concept of charge transport characteristics of conducting polymers. The rate constants of the ECL process were calculated by separate simulation procedure in the solution phase as well as in the polymer phase ECL. To enhance the stability of conducting polymers, synchrotron radiation induced cross-linking was performed. The effects were different from expected which were analyzed and rationalized by ex-situ Raman spectroscopic studies.

[Formulae and special characters can only be approximated here. Please see the pdf version of the Abstract for an accurate reproduction.] Several inert platinum complexes were synthesised: [(en)Pt([special character]-dpzm)2Pt(en)]4+, [{Pt(dien)}2[special character]-dpzm]4+, [{Pt(dien)}2[special character]-H2N-(CH2)6-NH2]4+, cis-[(NH3)2Pt([special character]--dpzm)2Pt(NH3)2]4+, trans-[Pt(NH3)2([special character]-dpzm)2]2+. Three active complexes, all with chloro ligands, were also synthesised: trans-[{Pt(NH3)Cl2}2[special character]-dpzm)], trans-[{Pt(NH3)2Cl}2[special character]-dpzm]2+ (di-Pt) and trans-[trans-{Pt(NH3)2Cl}2{trans-[Pt(NH3)2([special character]-dpzm)2]}]4+ (tri-Pt). 1H NMR established that multi-nuclear platinum complexes will preferentially associate in the DNA minor groove with a preference for A/T sequences, and with a binding constant [special character]-105 M-1, regardless of the charge, linking ligand, length or shape. Using [(en)Pt([special character]-dpzm)2Pt(en)]4+ and the oligonucleotide d(GC)5 it was determined that the metal complex binds G/C rich sequences also in the minor groove, but with a much reduced binding constant, 103 M-1. CD studies showed [(en)Pt([special character]-dpzm)2Pt(en)]4+ was able to induce a DNA conformation change from B-type to what appeared to be a partial Z-type. Transcription assays showed that even though the metal complex does not bind DNA covalently, it is still able to inhibit DNA transcription at particular sites. The complexes di-Pt, tri-Pt, [{Pt(dien)}2[special character]-dpzm]4+ and trans-[Pt(NH3)2([special character]-dpzm)2]2+ were tested for anti-cancer activity in the L1210 murine leukaemia cell line, and gave values of 3.8, 2.5, [special character]200 and 64 [special character]M respectively. In the cisplatin resistant line (L1210/DDP), trans-[Pt(NH3)2([special character]-dpzm)2]2+ showed an increase in activity with a drop to 32 [special character]M, while both di-Pt and tri-Pt showed decreases in activity to values of 8.8 and 3.6 [special character]M. In the human ovarian carcinoma 2008 cell line and its cisplatin resistant derivative C13[special character]5, both complexes showed good activity with values of 2.5 and 20.9 [special character]M respectively, but again both showed decreases in activity in the resistant line with values of 17.8 and 37.7 [special character]M respectively. To help explain the difference between activity of these complexes and the complexes BBR3464 and BBR3005, cell uptake and DNA interstrand cross-linking experiments were performed. The cell uptake studies showed that both di-Pt and tri-Pt are taken up by cells at very high levels, when administered at 100 [special character]M, thus indicating that the difference is unlikely to be due to large differences in cell uptake. The DNA interstrand cross-linking studies showed both complexes readily form interstrand adducts (50% interstrand cross-linking at 12 nM and 22 nM respectively, c.f cisplatin 3 [special character]M). These results suggest that the rigid nature of the dpzm linker may be affecting the DNA adducts formed, with more interstrand links being formed than BBR3464. Possibly, it is this that causes the large differences in cytotoxicity. The DNA binding of di-Pt and tri-Pt was examined with the nucleosides adenosine and guanosine and the dinucleotide d(GpG). Both complexes bound at the N7 of guanosine, but 2-fold slower than cisplatin. In addition, di-Pt bound at the N7 and either the N1 or N3 of adenosine, 7-fold slower than guanosine. Di-Pt forms a large variety of cross-links between two d(GpG) molecules, however it could not be established whether the 1,2-intrastrand adduct could be formed. Di-Pt, however, forms a 1,2-GG interstrand adduct with the oligonucleotide d(ATGCAT)2 resulting in a conformation change away from B-type DNA. The sugar pucker of the G3 nucleoside changes from 2[special character]-endo towards 3[special character]-endo, and the position of the nucleotide relative to the sugar changes from anti to syn. The ability of multi-nuclear platinum complexes to form covalent adducts in the DNA minor groove remains unclear. It appears that di-Pt can form up to 33% minor groove adducts with the oligonucleotide d(AT)5, but when added to the oligonucleotide d(GCCAAATTTCCG)2 no definite minor groove adducts are seen and the major adduct appears to be a 1,2-interstrand cross-link between the two A6's or between the G1 and G11. Finally, a study of the encapsulation of platinum complexes within cucurbit[7]uril (Q7) as a means of reducing drug toxicity was made. For complex A and di-Pt, encapsulation of the linker ligand occurred. The effect of Q7 on the rate of hydrolysis of di-Pt was at least a 3-fold reduction as compared to free di-Pt with guanosine. Studies with [{Pt(dien)}2[special character]-dpzm]4+/Q7 and the oligonucleotide d(CGCGAATTCGCG)2 showed that the metal complex could dissociate from the Q7 and associate with the oligonucleotide, where an equilibrium is achieved with 15 % of the metal complex bound to the oligonucleotide and 75 % encapsulated in Q7. Tests in the L1210 and L1210/DDP cancer cell lines showed that di-Pt/Q7 has almost the same activity compared to free di-Pt.

In biosensors, printing involves the transfer of materials, proteins or cells to a substrate. It offers many capabilities thatcan be utilized in many applications, including rapid deposition and patterning of proteins or other biomolecules.However, issues such as stability when using biomaterials are very common. Using proteins, enzymes, as biomaterialink require immobilizations and modifications due to changing in the structural conformation of the enzymes, whichleads to changes in the properties of the enzyme such as enzymatic activity, during the printing procedures andrequirements such as solvent solutions. In this project, an innovative approach for the fabrication of proteinmicroparticles based on cross-linking interchange reaction is presented to increase the stability in different solvents.The idea is to decrease the contact area between the enzymes and the surrounding environment and also preventconformation changes by using protein microparticles as an immobilization technique for the enzymes. The theory isbased on using a cross-linking reagent trigging the formation of intermolecular bonds between adjacent proteinmolecules leading to assembly of protein molecules within a CaCO3 template into a microparticle structure. TheCaCO3 template is removed by changing the solution pH to 5.0, leaving behind pure highly homogenous proteinmicroparticles with a size of 2.4 ± 0.2 μm, according to SEM images, regardless of the incubation solvents. Theenzyme model used is Horse Radish Peroxidase (HRP) with Bovine Serum Albumin (BSA) and Glutaraldehyde (GL)as a cross-linking reagent. Furthermore, a comparison between the enzymatic activity of the free HRP and the BSAHRPprotein microparticles in buffer and different solvents are obtained using Michaelis-Menten Kinetics bymeasuring the absorption of the blue product produced by the enzyme-substrate interaction using a multichannelspectrophotometer with a wavelength of 355 nm. 3,3’,5,5’-tetramethylbenzidine (TMB) was used as substrate. As aresult, the free HRP show an enzymatic activity variation up to ± 50 % after the incubation in the different solventswhile the protein microparticles show much less variation which indicate a stability improvement. Moreover, printingthe microparticles require high microparticle concentration due to contact area decreasing. However, usingmicroparticles as a bioink material prevent leakage/diffusion problem that occurs when using free protein instead.

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