Response surface optimisation of medium components for naringinase production from staphylococcus xylosus MAK 2

Response surface methodology was used to optimize the fermentation medium for enhancing naringinase production by Staphylococcus xylosus. The first step of this process involved the individual adjustment and optimization of various medium components at shake flask level. Sources of carbon (sucrose) and nitrogen (sodium nitrate), as well as an inducer (naringin) and pH levels were all found to be the important factors significantly affecting naringinase production. In the second step, a 22 full factorial central composite design was applied to determine the optimal levels of each of the significant variables. A second-order polynomial was derived by multiple regression analysis on the experimental data. Using this methodology, the optimum values for the critical components were obtained as follows: sucrose, 10.0%; sodium nitrate, 10.0%; pH 5.6; biomass concentration, 1.58%; and naringin, 0.50% (w/v), respectively. Under optimal conditions, the experimental naringinase production was 8.45 U/mL. The determination coefficients (R ²) were 0.9908 and 0.9950 for naringinase activity and biomass production, respectively, indicating an adequate degree of reliability in the model.

The effects of speech production and vocabulary training on different components of spoken language performance

A group of 21 hard-of-hearing and deaf children attending primary school were trained by their teachers on the production of selected consonants and on the meanings of selected words. Speech production, vocabulary knowledge, reading aloud, and speech perception measures were obtained before and after each type of training. The speech production training produced a small but significant improvement in the percentage of consonants correctly produced in words. The vocabulary training improved knowledge of word meanings substantially. Performance on speech perception and reading aloud were significantly improved by both types of training. These results were in accord with the predictions of a mathematical model put forward to describe the relationships between speech perception, speech production, and language measures in children (Paatsch, Blamey, Sarant, Martin, & Bow, 2004). These training data demonstrate that the relationships between the measures are causal. In other words, improvements in speech production and vocabulary performance produced by training will carry over into predictable improvements in speech perception and reading scores. Furthermore, the model will help educators identify the most effective methods of improving receptive and expressive spoken language for individual children who are deaf or hard of hearing.

A unified learning algorithm to extract principal and minor components

Recently, many unified learning algorithms have been developed to solve the task of principal component analysis (PCA) and minor component analysis (MCA). These unified algorithms can be used to extract principal component and if altered simply by the sign, it can also serve as a minor component extractor. This is of practical significance in the implementations of algorithms. Convergence of the existing unified algorithms is guaranteed only under the condition that the learning rates of algorithms approach zero, which is impractical in many practical applications. In this paper, we propose a unified PCA & MCA algorithm with a constant learning rate, and derive the sufficient conditions to guarantee convergence via analyzing the discrete-time dynamics of the proposed algorithm. The achieved theoretical results lay a solid foundation for the applications of our proposed algorithm.

Cellular and molecular components of plant defence against pathogens

This project investigated how plants respond to invading pathogens using microscopic, biochemical and genetic approaches. The development of transgenic plants containing the green fluorescent protein cloned from jellyfish enabled a new approach to studying plant defence genes. In particular, the role and involvement of the plant gene PAL1 was analysed.

A principal components analysis of New Zealand Board compostion : factors that influence an export strategy

Principal Topic Internationalisation strategies are important for company expansion because New Zealand, with its four million people, has such a small market. There may or may not exist ”agency costs” in the use of Outside Directors. Ownership patterns may also influence Internationalisation.

Methodology/Key Propositions This study uses Principal Component Analysis both in a grounded theory approach and in a confirmatory approach.

Results and Implications We find evidence that in New Zealand, contrary to some previous research elsewhere, outside Directors actually have less influence on Internationalisation than Inside Directors. Private ownership also seems to have a greater association with Internationalisation than other ownership types. A highly reliable sample of 1989 New Zealand company directors showed that such factors as gender, age and location and even industry sector were irrelevant. Two factors were important in explaining whether a company goes off-shore. These are the size and magnitude of the company as well as the ownership type and role of the CEO. In essence, this study validates New Zealand’s present strategy of ”picking winners”, that is, selecting firms based upon factor components. This study adds strength to that strategy because it identifies the concrete components that should be taken into account when picking companies for special treatment, e.g. export promotion.

Using omeprazole to link the components of the post-prandial alkaline tide in the spiny dogfish, Squalus acanthias

After a meal, dogfish exhibit a metabolic alkalosis in the bloodstream and a marked excretion of basic equivalents across the gills to the external seawater. We used the H⁺, K⁺-ATPase pump inhibitor omeprazole to determine whether these post-prandial alkaline tide events were linked to secretion of H⁺ (accompanied by Cl^–) in the stomach. Sharks were fitted with indwelling stomach tubes for pretreatment with omeprazole (five doses of 5mg omeprazole per kilogram over 48 h) or comparable volumes of vehicle (saline containing 2% DMSO) and for sampling of gastric chyme. Fish were then fed an involuntary meal by means of the stomach tube consisting of minced flatfish muscle (2% of body mass) suspended in saline (4% of body mass total volume). Omeprazole pretreatment delayed the post-prandial acidification of the gastric chyme, slowed the rise in Cl^– concentration of the chyme and altered the patterns of other ions, indicating inhibition of H⁺ and accompanying Cl^– secretion. Omeprazole also greatly attenuated the rise in arterial pH and bicarbonate concentrations and reduced the net excretion of basic equivalents to the water by 56% over 48h. Arterial blood CO₂ pressure and plasma ions were not substantially altered. These results indicate that elevated gastric H⁺ secretion (as HCl) in the digestive process is the major cause of the systemic metabolic alkalosis and the accompanying rise in base excretion across the gills that constitute the alkaline tide in the dogfish.

Multi-envelope HIV-1 vaccine devoid of SIV components controls disease in macaques challenged with heterologous pathogenic SHIV

A central obstacle to the design of a global HIV-1 vaccine is virus diversity. Pathogen diversity is not unique to HIV-1, and has been successfully conquered in other fields by the creation of vaccine cocktails. Here we describe the testing of an HIV-1 envelope cocktail vaccine. Six macaques received the vaccine, delivered by successive immunizations with recombinant DNA, recombinant vaccinia virus and recombinant envelope proteins. Following vaccination, animals developed a diversity of anti-envelope antibody binding and neutralizing activities toward proteins and viruses that were not represented by sequence in the vaccine. T-cells were also elicited, as measured by gamma-interferon production assays with envelope-derived peptide pools. Vaccinated and control animals were then challenged with the heterologous pathogenic SHIV, 89.6P. Vaccinated monkeys experienced significantly lower virus titers and better maintenance of CD4+ T-cells than unvaccinated controls. The B- and T-cell immune responses were far superior post-challenge in the vaccinated group. Four of six vaccinated animals and only one of six control animals survived a 44-week observation period post-challenge. The present report is the first to describe pathogenic SHIV disease control mediated by a heterologous HIV-1 vaccine, devoid of 89.6 or SIV derivatives.

Hydrodynamic flow focusing to study the isolated effects of the flow components

Biological fluids such as blood, proteins and DNA solutiosn moving within fluidic channels can potentially be exposed to high level of shear, extension or mixed stress, either in vitro such as industrial processing of blood products or in vivo such as ocurrs in some pathological conditions. This exposure to a high level of strain can trigger some reactions. In most of the cases the nature of the flow is mixed with shear and extensional components. The ability ot isolate the effects of each component is critical in order to understand the mechanisms behind the reactions and potentially prevent them. Applying hydrodynamic flow focusing, we present in this investigation the characterization of microchannels that allow study of the regions of high shear or high extension strain rate. Micro channels were fabricated in polydimethyl siloxane (PDMS)  using standard soft-lithography techniques with a photolithographically patterned mold. Characterization of the regions with high shear and high extension strain rate is presented. Computational Fluid Dynamics (CFD) simulations in three dimensions have been carried out to gain more detailed local flow information, and the results have been validated experimentally. A comparison between the numerical models and experiment and is presented. The advantages of microfluidic flow focusing in the study  of the effects of shear and extension strain rates for biological fluids are outlined.

On the components of the dielectric constants of ionic liquids : ionic polarization?

According to dielectric spectroscopy measurements, ionic liquids (ILs) have rather modest dielectric constants that reflect contributions from distortion and electronic polarization caused by the molecular polarizability as well as the orientation polarization caused by the permanent dipole moment of the ions. To understand the relative importance of these various contributions, the electronic polarizabilities of 27 routinely used ionic liquid ions of different symmetry and size were calculated using ab initio-based methods such as HF and MP2. Using the Clausius–Mossotti equation, these polarizabilities were then used to obtain the electronic polarization contribution (ε_op) to the dielectric constants of six ionic liquids, [C₂mim][BF₄], [C₂mpyr][N(CN)₂], [C₂mim][CF₃SO₃], [EtNH₃][NO₃], [C₂mim][NTf₂] and [C₂mim][EtSO₄]. Theoretical ε_op values were compared to experimental refractive indices of these ionic liquids as well as to those of traditional molecular solvents such as water, tetrahydrofuran (THF), dimethylsulfoxide (DMSO) and formamide. The dipole moments of the ions were also calculated, and from these it is shown that the molecular reorientation component of the dielectric constants of the ionic liquids consisting of ions with small or negligible dipole moments is quite small. Thus it is concluded that a contribution from a form of “ionic polarization” must be present.

Composite cell components for elevated temperature all-solid-state Li-ion batteries

Application of Li-ion batteries with liquid electrolytes at elevated temperatures (above 60°C) is limited due to the decomposition of the electrolyte. Stable solid state electrolytes can solve this problem, but the conductivity of these electrolytes are relatively low, the interfacial contacts with the electrodes are poor, and the charge transfer kinetics in the electrodes are limited. Solutions for these problems by using composite electrodes and electrolytes have been investigated and the results are described. A new concept for making all-solid-state Li-ion batteries that can be applied in the temperature range between room temperature and about 150°C will be presented.

Carriers and components

Parametric modelling is a powerful means of geometric control. Within the field of architecture, there are wide ranging possibilities in form generation, self analysing structural systems and performative building facades. This thesis has investigated the potential of parametric modelling as a design tool, specifically in the exploration of architectural surfaces.