The applicability of trauma studies within an examination of postcolonial literature has been a contested topic for scholars in both fields. Additionally, scholarship regarding Amitav Ghosh’s postcolonial science fiction novel The Calcutta Chromosome encourages various readings of the novel but does not currently offer a cohesive examination of all its thematic disciplines and stylistic elements. Through an examination of this postcolonial novel, I will provide a more holistic reading of the novel through an application of trauma studies that explores its representation of the internal postcolonial conflict regarding Western and non-Western historiographies. My analysis will focus on the lexical, character, and narrative levels of the novel through its dominant medical, technological, postcolonial, and political themes for inclusions of Caruth’s aporia related to the manifestation of trauma in literature.

As an atomic layer of sp2-hybridized carbon atoms closely packed in a honeycomb lattice, graphene has been attracting increasing attention since its discovery in 2004 due to its extraordinary physicochemical properties. Graphene oxide (GO), a non-stoichiometric graphene derivative with the carbon plane abundantly decorated with hydroxyl, epoxide and carboxylic groups, can be massively and cost-effectively produced from natural graphite following Hummers method. GO has greater aqueous solubility than pristine graphene due to its oxygen-functionalities. Various solution-based chemical methods can be applied to GO, which has stimulated a new research area called ???wet chemistry of grahene???. Among them, chemical reduction of GO provides a facile route for large-scale synthesis of graphene. With abundant oxygen-functionalities in its structure, GO can potentially act as a suitable precursor for chemical modifications of graphene through methods used in organic chemistry. Special attention should be paid to that the hydroxyl groups in GO belong to tertiary alcohols, and steric hindrance should be considered when performing chemical modifications. Diethylaminosulfur trifluoride (DAST), a fluorinating reagent, is ineffective in fluorinating GO due to the steric hindrance of tertiary hydroxyls. However, DAST is effective in reducing GO. The capability of DAST for GO reduction is close to hydrazine, but the reduction reaction can be performed at lower temperature for DAST. As a two-dimensional (2D) nanomaterial with good aqueous solubility, biocompatibility and excellent intrinsic mechanical properties, GO is particularly useful in preparing 3D hybrid hydrogel scaffolds for tissue engineering applications.

Västerås is a city with an industrial heritage. One of the larger companies in Västerås is ABB AB, which has multiply businesses located at the area Finnslätten. High concentrations of trichloroethene (TCE) were found in the soil and groundwater at Finnslätten 1 during a phase II environmental site assessment. Due to the result of the assessment a supplementary investigation and a site specific risk assessment were made of building 358. The source zone and plume of trichloroethene have not been characterized even after several investigations at the site. The aim of this study was to make a risk assessment of three other buildings inside the area were degreasing with TCE have historical taken place. The collected information resulted in a risk class 2 of the three objects and shows that the buildings might be potential pre-emission sources of trichloroethene. The second aim contains a comparison between traditional and alternative approaches to enlighten the importance of effective characterization methods. Two potential characterization strategies were chosen; TRIAD approach and CMF approach. The result showed the importance of systematic project planning, dynamic work planning strategy and the use of multiple techniques to form the best “hybrid” during characterization of DNAPL. In order to bring the investigation to a successful conclusion it is of great importance to consider the uncertainties or diminish the uncertainties by collecting essential information.

The McTronX Research group at the Potchefstroom campus of the North-West University, aims to establish a knowledge base on active magnetic bearing (AMB) systems. Up to date, the group has established a firm knowledge base on various topics related to AMB systems. A recent focus was the design and development of a high speed AMB supported rotor system called the rotor delevitation system (RDS) to analyse rotor drops. During the testing phase of the RDS, the machine exhibited vibrations, of which the origins were unknown. The research presented in this dissertation sets out to characterize the vibrations of the RDS, which is the group’s first attempt to fulfil the need for characterizing vibrations in an AMB supported rotor. Emphasis is placed on characterizing the natural response of the RDS rotor, stator and integrated system. The research project is defined in terms of four main objectives: rotor and stator characterization, modelling, system characterization and rotor dynamic diagnostics. A comprehensive literature study introduces the fundamental concepts regarding vibrations of single and multiple degree of freedom systems. These concepts include; natural frequencies, damping, machine vibrations, rotor dynamics and modelling techniques. These modelling techniques are introduced to verify the experimental methodology used to determine the natural frequencies. A critical overview of the literature contextualises the theory with the research investigation. For the RDS rotor and stator characterization, a modal analysis process also known as the “bump test” is implemented in order to validate the bending natural frequencies of the rotor and stator. A simulation model of the RDS is constructed in the finite element (FE) package DyRoBeS®. The model is verified with a numerical and an analytical model and validated with the measured bending natural frequencies of the RDS rotor. For the system characterization, a number of modal analysis processes are implemented, which validates the rigid body natural frequencies of the RDS. These frequencies are also used to validate the FE simulation. The origins of the synchronous vibration harmonics are verified by formulating and evaluating hypotheses according to different modal analysis processes. From the RDS rotor modal analysis it was identified that a bending natural frequency of the rotor is situated at approximately 443.33 Hz. This was verified using the FE simulation model. During the system modal analyses, it was identified that only one rigid body natural frequency, situated at approximately 62 Hz, is excited. This frequency increases with the differential gain control parameter of the system up to approximately 140 Hz. After evaluating two hypotheses regarding the origins of the synchronous vibrations harmonics, it was verified that non-circularity of the rotor at the measuring positions is the cause. Overall the objectives of the study were addressed by characterizing the natural frequencies of the rotor, stator and RDS system. This include the mode forms of the rigid body and bending natural frequencies of the system. The results of the verification and validation methods correlated, which imply these methods are reliable to identify the origins of vibrations in rotor-bearing systems. The differential gain control parameter of the AMBs control the equivalent damping in the RDS. An increase in this parameter should lead to a decrease in amplitude and frequency of the maximum vibration, and vice versa. However, it was noted that an increase in this parameter caused a linear increase in the rigid body natural frequency. The literature indicates that this effect can only be caused by an increase in system stiffness. It is therefore recommended to evaluate the stiffness of the system as a function of the differential gain control parameter. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

The increased interest in the use of light ion therapy is due to the high dose conformity to the target and the dense energy deposition along the tracks resulting in increased relative biological effectiveness compared to conventional radiation therapy. In spite of the good clinical experience, fundamental research on the characteristics of the ion beams is still needed in order to be able to fully explore their use. Therefore, a Monte Carlo track structure code, KITrack, simulating the transport of electrons in liquid water, has been developed and used for calculation of parameters of interest for beam characterization. The influence of the choice of the cross sections for the physical processes on the electron tracks has also been explored. As an alternative to Monte Carlo calculations a semi-analytical approach to calculate the radial dose distribution from ions, has been derived and validated. In advanced radiation therapy, accurate characterization of the beams has to be complemented by comprehensive radiobiological models, which relate the dose deposition into the cells to the outcome of the treatment. The second part of the study has therefore explored the influence of heterogeneity in the dose deposition into the cells as well as the heterogeneity in the cells sensitivity to radiation on the probability of controlling the tumor. Analytical expressions for tumor control probability including heterogeneous dose depositions or variation of radiation sensitivity of cells and tumors have been derived and validated with numerical simulations. The more realistic case of a combination of these effects has also been explored through numerical simulations. The MC code KITrack has evolved into an extremely useful tool for beam characterization. The tumor control probability, given by the analytical derived expression, can help improve radiation therapy. A novel anisotropy index has been proposed. It is a measure of the absence of isotropy and provides deeper understanding of the relationship between beam quality and biological effects. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Micromachined needles have been shown to successfully transport biological molecules into the body with minimal invasiveness and pain, following the insertion of needles into the skin. The aim of this research is to demonstrate that micromachined hollow polymer needle arrays fabricated using UV lithography into micromolds, a potential batch-manufacturable process, can exhibit comparable insertion and injection performance to conventional hypodermic needles for drug delivery into skin. A dual-exposure-and-single-development process flow is proposed for the above-mentioned UV lithography into micromolds approach to construct a pyramidal-tip hollow microneedle array with an integral baseplate and fluidic manifold. The developed process ultimately resulted in the ability to fabricate a 10×10 array of hollow SU-8 microneedles measuring 825 μm in height, 400 μm in width, and possessing a lumen of 120 μm in diameter. The tip diameter of the microneedles ranges from 15 μm to 25 μm. The insertion force of single needles characterized using excised porcine skin as a substrate is 2.4±1.2 N. Nevertheless, the high insertion force of 2.4 N per needle may cause a significant concern when a large number of needles are required to insert into skin for drug delivery. Conventional hypodermic needles have two key structural characteristics: a sharp beveled tip and a large side-terminated lumen. Integration of these two key characteristics of hypodermic needles into microneedle design can potentially enhance microneedle performance. To reduce the insertion force and to incorporate the two key characteristics of hypodermic needles into the design of microneedles, a new needle tip design, namely the hypodermic-needle-like design, is presented. A 6×6 array of hypodermic-needle-like microneedles of 1 mm in height, approximate 350 μm in width, and with a lumen of 150 μm in diameter is demonstrated with successful insertion of the needle array into skin and an 85% lumen openness yield. The insertion force is significantly reduced by an order of magnitude with the new needle tip design and is 0.275±0.113 N per needle, comparable to that of hypodermic needles, i.e., 0.284±0.059 N. The hypodermic-needle-like microneedles exhibit a margin of safety of 180 for successful needle insertion into skin prior to needle fracture. A successful manual fluid injection into skin using single microneedle is demonstrated. The micromachined hypodermic-needle-like polymer needle arrays presented in this dissertation are fabricated using UV lithography into micromolds, a potentially batch-manufacturable process, and exhibit comparable insertion performance to conventional hypodermic needles. Injection capability into skin is also demonstrated with a hypodermic-needle-like microneedle, illustrating the utility of these devices.

The HIV-1 transactivator of transcription (Tat) is a protein essential for both viral gene expression and virus replication. Tat is an RNA-binding protein that, in cooperation with host cell factors cyclin T1 and cyclin-dependent kinase 9, regulates transcription at the level of elongation. Tat also interacts with numerous other intracellular and extracellular proteins, and is implicated in a number of pathogenic processes. The Tat protein is encoded by two exons and is 101 residues in length. The first exon encodes a 72-residue molecule that activates transcription with the same proficiency as the full-length protein. The physico-chemical properties of Tat make it a particularly challenging target for structural studies: Tat contains seven cysteine residues, six of which are essential for transactivation, and is highly susceptible to oxidative cross-linking and aggregation. In addition, a basic segment (residues 48-57) gives the protein a high net positive charge of +12 at pH 7, endowing it with a high affinity for anionic polymers and surfaces. In order to study the structure of Tat, both alone and in complex with partner molecules, we have developed a system for the bacterial expression and purification of polyhistidine-tagged and isotopically enriched (in 15N and 15N /13C) recombinant HIV-1 Tat1-72 (BH10 isolate) that yields large amounts of protein. These preparations have facilitated the assignment of 95% of the non-proline backbone resonances using heteronuclear 3-dimensional nuclear magnetic resonance (NMR) spectroscopy. Analysis by mass spectrometry and NMR demonstrate that the cysteine-rich Tat protein is unambiguously reduced and monomeric in aqueous solution at pH 4. NMR chemical shifts and coupling constants suggest that it exists in a disordered conformation. Line broadening and multiple peaks in the cysteine-rich and core regions suggest that transient folding occurs in two of the five sequence domains. NMR relaxation parameters were measured and analysed by spectral density and model-free approaches both confirming the lack of structure throughout the length of the molecule. The absence of a fixed conformation and the observation of fast dynamics are consistent with the ability of the Tat protein to interact with a wide variety of proteins and nucleic acid lending further support to the concept that Tat exists as an intrinsically disordered protein.

Hemogen (Hemgn) is reported as a tissue specific transcriptional regulator in testis as well as hematopoietic tissues. It is known that Hemgn positively regulates erythroid differentiation; however,the underlying molecular mechanism is not well understood. In the current study, using proteomic approach in combination with other molecular biology tools,we have attempted to decipher the role of Hemgn in differentiating Murine erythroblast leukemia (MEL) cells as a model system. Our study reveals that Hemgn predominantly interacts with transcriptional regulators, chromatin modifiers and histones. Furthermore, using Chromatin Immunoprecipitation and knockdown approach, we have demonstrated that Hemgn is recruited to the b-globin locus, which is known to be activated during erythroid differentiation. Based on the results,we speculate that Hemgn acts as a tissue specific histone chaperone that regulates transcription during erythroid differentiation.

The McTronX Research group at the Potchefstroom campus of the North-West University, aims to establish a knowledge base on active magnetic bearing (AMB) systems. Up to date, the group has established a firm knowledge base on various topics related to AMB systems. A recent focus was the design and development of a high speed AMB supported rotor system called the rotor delevitation system (RDS) to analyse rotor drops. During the testing phase of the RDS, the machine exhibited vibrations, of which the origins were unknown. The research presented in this dissertation sets out to characterize the vibrations of the RDS, which is the group’s first attempt to fulfil the need for characterizing vibrations in an AMB supported rotor. Emphasis is placed on characterizing the natural response of the RDS rotor, stator and integrated system. The research project is defined in terms of four main objectives: rotor and stator characterization, modelling, system characterization and rotor dynamic diagnostics. A comprehensive literature study introduces the fundamental concepts regarding vibrations of single and multiple degree of freedom systems. These concepts include; natural frequencies, damping, machine vibrations, rotor dynamics and modelling techniques. These modelling techniques are introduced to verify the experimental methodology used to determine the natural frequencies. A critical overview of the literature contextualises the theory with the research investigation. For the RDS rotor and stator characterization, a modal analysis process also known as the “bump test” is implemented in order to validate the bending natural frequencies of the rotor and stator. A simulation model of the RDS is constructed in the finite element (FE) package DyRoBeS®. The model is verified with a numerical and an analytical model and validated with the measured bending natural frequencies of the RDS rotor. For the system characterization, a number of modal analysis processes are implemented, which validates the rigid body natural frequencies of the RDS. These frequencies are also used to validate the FE simulation. The origins of the synchronous vibration harmonics are verified by formulating and evaluating hypotheses according to different modal analysis processes. From the RDS rotor modal analysis it was identified that a bending natural frequency of the rotor is situated at approximately 443.33 Hz. This was verified using the FE simulation model. During the system modal analyses, it was identified that only one rigid body natural frequency, situated at approximately 62 Hz, is excited. This frequency increases with the differential gain control parameter of the system up to approximately 140 Hz. After evaluating two hypotheses regarding the origins of the synchronous vibrations harmonics, it was verified that non-circularity of the rotor at the measuring positions is the cause. Overall the objectives of the study were addressed by characterizing the natural frequencies of the rotor, stator and RDS system. This include the mode forms of the rigid body and bending natural frequencies of the system. The results of the verification and validation methods correlated, which imply these methods are reliable to identify the origins of vibrations in rotor-bearing systems. The differential gain control parameter of the AMBs control the equivalent damping in the RDS. An increase in this parameter should lead to a decrease in amplitude and frequency of the maximum vibration, and vice versa. However, it was noted that an increase in this parameter caused a linear increase in the rigid body natural frequency. The literature indicates that this effect can only be caused by an increase in system stiffness. It is therefore recommended to evaluate the stiffness of the system as a function of the differential gain control parameter. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

Temporal and wavelet characteristics of initial breakdown pulses are meticulously studied especially during the earliest moment of lightning events. Any possible features during the earliest moment that may exist which lead to either negative cloud-to-ground (CG), positive cloud-to-ground, cloud or isolated breakdown flashes in Sweden are investigated. Moreover, the occurrence of narrow bipolar pulses (NBPs) as part of a CG event that has been recorded from tropical thunderstorms are also included in the investigation. Electric field signatures selected from a collection of waveforms recorded using fast electric field broadband antenna system installed in Uppsala, Sweden and Skudai, South Malaysia are then carefully analyzed in order to observe any similarities or/and differences of their features. Temporal analysis reveals that there are significant distinctions within the first 1 ms among different types of lightning flashes. It is found that a negative CG flash tends to radiate pulses more frequently than other flashes and a cloud flash tends to radiate shorter pulses than other flashes but less frequently when compared to negative CG and isolated breakdown flashes. Perhaps, the ionization process during the earliest moment of negative CG flashes is more rapid than other discharges. Using a wavelet transformation, it can be suggested that the first electric field pulse of both negative CG and cloud flashes experiences a more rapid and extensive ionization process compared to positive CG and isolated breakdown flashes. Further temporal analysis on NBPs found to occur as part of CG flashes show the disparity of the normalized electric field amplitude between the NBPs prior to and after the first return stroke. This indicates that the NBPs intensities were influenced by the return stroke events and they occurred in the same thundercloud. The similarity between the temporal characteristics of NBPs as part of CG flashes and isolated NBPs suggests that their breakdown mechanisms might be similar.