No description available.

he thermal behaviour in the solid state of various substituted aminobenzoic acids (3-aminobenzoic acid (3-ABA), 4-aminobenzoic acid (4-ABA), 3-aminosalicylic acid (3-ASA), 4-aminosalicylic acid (4-ASA), and 5-aminosalicylic acid (5-ASA), as well as the "parent" benzoic acid (BA) and salicylic acid (SA) as reference substances, and possible decomposition products: 2-aminophenol (2-AP), 3-aminophenol (3-AP) and 4-aminophenol (4-AP), has been examined. The various sets of isomers studied showed considerable and interesting differences. Most sublimed well before melting, generally with an increasing rate of mass loss beyond their very different melting points. The existence of ranges of isomers allows for the comparison of their behaviour, including such aspects as melting, vaporisation, and the influence of products on the course of decomposition of initially-solid reactants. The differences in behaviour of 4-ASA and 5-ASA were the most remarkable, with 5-ASA being far more stable and apparently not decarboxylating readily, while 4-ASA sublimed at temperatures below the melting point, becoming less stable and decarboxylating in the liquid form. There is also a marked difference in the thermal behaviour of 3-ASA, as compared with 4-ASA and 5-ASA. It decarboxylated at higher temperatures (260°C) than 4-ASA (150°C). The addition of the possible decomposition products to these compounds showed faster decomposition for 4-ASA mixed with 3-AP. The sodium salts of 3-ASA and 4-ASA decarboxylate while that of 5-ASA did not. Binary mixtures of the substances listed above with beta-cyclodextrin (BCD), hydroxypropylbeta-cyclodextrin (HPBCD) and gamma-cyclodextrin (GCD) were prepared (by simple physical mixing or by kneading with a solvent) and were then examined for possible interactions using DSC, TG-FTIR, HSM, XRD and NMR. Generally, kneaded mixtures showed greater changes in thermal behaviour from that of the individual components than the physical mixtures, but changes in the physical mixtures were also significant. Comparison of the effects of the different CDs on the thermal behaviour of individual ASA isomers showed that HPBCD has the greatest interaction with 3-ASA and 5-ASA, followed by GCD, while BCD generally showed the least interactions. For 4-ASA, the effect of GCD is more marked than for 3-ASA and 5-ASA. GCD has the largest molecular cavity.

Plasmid pBSSB1 is a 27 kb linear DNA with proteins attached at the 5? termini. It encodes the H: z66 flagellar antigen in Salmonella enterica serovar Typhi (S. Typhi) isolated from Indonesia. Together with the H: j or H: d flagellar antigen encoded by the host chromosome, pBSSB1 renders expression of the flagellar antigen biphasic in S. Typhi. Following the discovery of pBSSB1, initial bioinformatic analyses were carried out. However, no genetic analysis of replication and stability functions was conducted. Such studies form the basis of the present work. Plasmid pBSSB2, that contains a kanamycin cassette inserted at position 1295 bp of pBSSB1, was used in the present investigation. The first objective of the work was to develop a method of purification for the linear plasmid. Conventional plasmid extraction methods which had been used previously were found to produce a very poor yield of plasmid DNA. It was shown in the present study that a proteinase-K treatment was essential for the removal of the linear plasmid terminal proteins to avoid loss of the plasmid in the phenol-chloroform-isoamylalcohol treatment which removes cellular proteins from the plasmid DNA.The region containing the basic replicon of pBSSB2 was identified by screening for a region that was able to support replication in E. coli of a ColE1-like plasmid in a polA host (in which it would not normally replicate). This identified a 2831 bp fragment encompassing nucleotides 12820 to 15649 of pBSSB2. It was expected that this would encode an initiator of replication such as a Rep protein. However, mutagenesis studies showed that none of the annotated ORFs in this fragment was essential for replication. Candidate ORFs, not identified in the original annotation, have been suggested that remain to be tested as possible candidates for the rep encoding gene. The possibility of an alternative RNA primed initiation of replication has also been hypothesized. An adjacent region was found to exert strong incompatibility against pBSSB2, suggesting that it might encode a repressor of replication. The minimum region conferring incompatibility was 179 bp, encompassing nucleotides 10840 bp to 11018 bp of pBSSB2. A six base pair imperfect repeat, (G/T) (G/A) TGTT was found within this sequence. It is hypothesized that these imperfect repeats may function as iterons that titrate a Rep protein and regulate pBSSB2 replication. A 1023 bp region (nucleotides 7236 to 8258 of pBSSB2) was found to confer stability in E. coli upon an otherwise unstable circular plasmid. Mutational analysis showed that an annotated ORF within this region (ORF09) was required for plasmid stabilisation. When expressed independently from an expression vector ORF09 killed host cells. It is proposed that the stability function acts as a toxin-antitoxin system, although the antitoxin has not yet been identified. A candidate promoter for a putative countertranscript and two potential ORFs as candidates for encoding the antitoxin have been suggested for future work to identify the antitoxin. The preliminary functional characterization of pBSSB2 has contributed to our general understanding of the replication and stability functions of linear plasmids. However, further work will be required to achieve a complete understanding of the molecular basis of these functions in pBSSB2.

In estimating econometric time series models, it is assumed that the parameters remain constant over the period examined. This assumption may not always be valid when using data which span an extended period, as the underlying relationships between the variables in these models are exposed to various exogenous shifts. It is therefore imperative to examine the stability of models as failure to identify any changes could result in wrong predictions or inappropriate policy recommendations. This research proposes a method of estimating the location of break points in linear econometric models with endogenous regressors, estimated using Generalised Method of Moments (GMM). The proposed estimation method is based on Wald, Lagrange Multiplier and Difference type test statistics of parameter variation. In this study, the equation which sets out the relationship between the endogenous regressor and the instruments is referred to as the Jacobian Equation (JE). The thesis is presented along two main categories: Stable JE and Unstable JE. Under the Stable JE, models with a single and multiple breaks in the Structural Equation (SE) are examined. The break fraction estimators obtained are shown to be consistent for the true break fraction in the model. Additionally, using the fixed break approach, their $T$-convergence rates are established. Monte Carlo simulations which support the asymptotic properties are presented. Two main types of Unstable JE models are considered: a model with a single break only in the JE and another with a break in both the JE and SE. The asymptotic properties of the estimators obtained from these models are intractable under the fixed break approach, hence the thesis provides essential steps towards establishing the properties using the shrinking breaks approach. Nonetheless, a series of Monte Carlo simulations conducted provide strong support for the consistency of the break fraction estimators under the Unstable JE. A combined procedure for testing and estimating significant break points is detailed in the thesis. This method yields a consistent estimator of the true number of breaks in the model, as well as their locations. Lastly, an empirical application of the proposed methodology is presented using the New Keynesian Phillips Curve (NKPC) model for U.S. data. A previous study has found this NKPC model is unstable, having two endogenous regressors with Unstable JE. Using the combined testing and estimation approach, similar break points were estimated at 1975:2 and 1981:1. Therefore, using the GMM estimation approach proposed in this study, the presence of a Stable or Unstable JE does not affect estimations of breaks in the SE. A researcher can focus directly on estimating potential break points in the SE without having to pre-estimate the breaks in the JE, as is currently performed using Two Stage Least Squares.

No description available.

Falls are the leading cause of injuries among Canadians who are aged at 65 years and over. The assessment of dynamic stability has been proved as an effective method to identify fall-prone elderly individuals, which is essential to fall prevention. Tai Chi has been recommended as an effective exercise to prevent falls by the American Geriatric Society and British Geriatric Society. It is important to examine dynamic stability among Tai Chi practitioners and to explore the mechanisms of the effects of Tai Chi practice on fall prevention. This study examined the dynamic postural stability which is assessed by center of mass (COM) range of motion, COM - center of pressure (COP) separation, and temporospacial measures of gait during obstacle-walking in two groups: Tai Chi group and healthy controls. Fifteen participants in each group were asked to complete two walking conditions, level walking and 20cm-obstacle walking. Results showed that when compared with Tai Chi group, control group adopted a conservative crossing strategy with a significantly smaller crossing stride, higher heel clearance, and smaller pre horizontal distance to make obstacle crossing as safe as possible. This conservative strategy indicates the inability to cross obstacle casually and it may be associated with the decline in muscle strength and proprioception. It also showed that Tai Chi practitioners displayed a significantly larger COM range of motion in both anteroposterior (AP) and mediolateral (ML) direction (p<0.05) and a significantly larger COM-COP separation in ML direction (p <0.01), as compared with control group. The larger range of motion of COM and distance between COM and COP indicates that Tai Chi practitioners have a better ability to tolerate unsteadiness, which means if perturbation occurs, Tai Chi practitioners have a larger range to shift COM in the boundary of base of support.

Settling basins can be shortened by using a stack of horizontal parallel plates which develop boundary layers in which sedimentation can occur. The purpose of this study is to examine the design parameters for such a system and to apply this approach to a fish rearing channel in which settling length is strictly limited. Flow between parallel rough and smooth plates has been modelled together with sediment concentration profile. Accurate description of boundary layer flow requires the solution of Navier-Stokes equations, and due to the complexity of the equations to be solved for turbulent flow some assumptions are made to relate the Reynolds stresses to turbulent kinetic energy and turbulent energy dissipation rate. The simplified equations are solved using a numerical method which uses the approach given by the TEACH code. The flow parameters obtained from the turbulent flow model are used to obtain the sediment concentration profile within the settling plates. Numerical solution of the sedimentation process is obtained by adopting the general transport equation. The lower plate is assumed to retain sediments reaching the bottom. The design of a sedimentation tank for a fish rearing unit with high velocity of flow has been investigated. The effectiveness of the sedimentation tank depends on the uniformity of flow attained at the inlet, and experiments were conducted to obtain the most suitable geometric system to achieve uniform flow distribution without affecting other performances of the fish rearing unit. The main difficulties to overcome were the heavy circulation present in the sedimentation tank and the clogging of the distributing system by suspended particles. Several distributing systems were investigated, the best is discussed in detail. It was concluded that a stack of horizontal parallel plates can be used in fish rearing systems where space is limited for settling sediments. Flow distribution along the vertical at the entrance to the plates determines the efficiency of the sediment settling process and a suitable geometrical configuration can be constructed to distribute the high velocity flow uniformly across the vertical. Numerical modelling of sediment removal ratio for flow between smooth and rough parallel plates has been calculated. The results show that almost the same pattern of sediment deposition occurs for both the smooth-smooth and rough-smooth plate arrangements. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

In this thesis catastrophe theory is applied to the voltage stability problem in power systems. A general model for predicting voltage stability from the system conditions is presented and then applied to both a simple 2-bus explanatory power system and to a larger more realistic power system. The model is based on the swallowtail catastrophe which with its three control variables is able to determine the voltage stability of the system. The model is derived directly from the systems equations. The voltage stability of the system at each specified system bus is determined by comparing the values of the swallowtail catastrophe control variables with those of the unique region of voltage stability. The control variables are calculated from the system operating conditions. If the control variables specify a point inside the stability region, the system is voltage stable; otherwise it is voltage unstable. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The RNA-binding protein HuR is involved in numerous aspects of the RNA life-cycle. It is known for its ability to stabilize AU-Rich Element (ARE)-containing transcripts in the cytoplasm. The transcript of cIAP1, an important protein involved both in the regulation of apoptosis and NF-κB signaling, contains four such AREs, raising the question of whether HuR can modulate the stability of cIAP1 mRNA. First, using C2C12 cells, we observed a positive correlation between cIAP1 mRNA levels and HuR cytoplasmic localization. We then show that knockdown of HuR in U2OS cells results in a decrease in steady-state cIAP1 mRNA levels through destabilization of the cIAP1 mRNA. Furthermore, we are able to show in vitro that HuR binds directly to the second of the four AREs in the 3’ UTR. The direct link between the binding of HuR to the second ARE and its effect on cIAP1 mRNA stability remains to be shown.

Thesis: "The stability of banks in the crisis" presents an analysis of the impact of the financial crisis on the banking sector and individual banks and a demonstration of the behavior of banks in crisis situation. The thesis is divided into four chapters. The first chapter deals with the definition of instability and explain the functioning of the financial crisis. The second chapter discusses the issue of deposit insurance and the possibility of compensation payments during the bank's collapse. The third chapter shows the influence and role of central banks as the creator of the banking environment and as the main supervisory authority. The fourth chapter focuses on the stability of banks from different perspectives, that the bank's activity was not significantly affected during and after the financial crisis.