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.

Exploring molecular changes at the surface of polypropylene after accelerated thermomolecular adhesion treatments

A central composite rotatable design (CCRD) method was used to investigate the performance of the accelerated thermomolecular adhesion process (ATmaP), at different operating conditions. ATmaP is a modified flame-treatment process that features the injection of a coupling agent into the flame to impart a tailored molecular surface chemistry on the work piece. In this study, the surface properties of treated polypropylene were evaluated using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). All samples showed a significant increase in the relative concentration of oxygen (up to 12.2%) and nitrogen (up to 2.4%) at the surface in comparison with the untreated sample (0.7% oxygen and no detectable nitrogen) as measured by XPS. ToF-SIMS and principal components analysis (PCA) showed that ATmaP induced multiple reactions at the polypropylene surface such as chain scission, oxidation, nitration, condensation, and molecular loss, as indicated by changes in the relative intensities of the hydrocarbon (C₃H₇⁺ , C₃H₅⁺ , C₄H₇⁺, and C₅H₉⁺), nitrogen and oxygen-containing secondary ions (C₂H₃O⁺, C₃H₈N⁺, C₂H₅NO⁺, C₃H₆NO⁺, and C₃H₇NO⁺). The increase in relative intensity of the nitrogen oxide ions (C₂H₅NO⁺ and C₃H₇NO⁺) correlates with the process of incorporating oxides of nitrogen into the surface as a result of the injection of the ATmaP coupling agent.

Optimization of zeaxanthin and β-carotene extraction from Chlorella saccharophila isolated from New Zealand marine waters

Zeaxanthin is an important natural pigment which has found commercial application in food and nutritional supplements. Its potential widespread use requires an easy and effective extraction methodology for obtaining higher yields. Extraction from Chlorella sp. under optimized conditions demonstrated a marked reduction in extraction time (13.48min) compared with a control experiment (30min). The extraction conditions such as solvent/cell dry weight (CDW) ratio, power, pulse, time and their combinations were optimized using response surface methodology (RSM). Almost all the variables were shown significantly (p-value <0.05) affect the carotenoid yield. Significant interaction (p-value <0.05) was observed with a substantial effect on zeaxanthin yield for solvent/CDW ratio and power, as well as power and time, whereas the β-carotene control exhibited significant interaction between solvent/CDW ratio and pulse, as well as between pulse and time. The R 2-value approached unity in both models, demonstrating their accuracy. Data obtained from these interactions were used to construct 3D response plots. Solvent/CDW ratio of 67.38μlmg-1, power 27.82% (total power 500W), pulse length of 19.7s and time 13.48min were found to be the optimized conditions for zeaxanthin (11.2mgg-1) and β-carotene (4.98mgg-1) extraction.

The inhibitory effect of stevioside on bacillus cereus growth in milk: validation and its response surface optimization

Stevioside, a glycoside present in the leaves of Stevia rebaudiana Bertoni, offers therapeutic benefits such as anti-hyperglycemic, anti-hypertensive, antiinflammatory, anti-tumor, diuretic and immune influencing properties. In this work antimicrobial activity of stevioside against Bacillus cereus, a major source of milk contamination was investigated. The isolate was confirmed by various biochemical and 16S rRNA gene sequencing. The effect of temperature, incubation time and concentration of stevioside was optimized from a central composite response surface design. The standard plate count (SPC) of pasteurized milk was drastically reduced in comparison to toned and fresh milk. The optimal temperature, incubation time and stevioside concentration were observed to be 60.23°C, 21 h, and 275 μg/ mL respectively. The synergism of stevioside with the external factors (temperature and time) against B. cereus was observed. Our studies showed that addition of stevioside in fresh as well as pasteurised milk would control growth of B. cereus in milk.

Enhancement of ion dynamics in organic ionic plastic crystal/PVDF composite electrolytes prepared by co-electrospinning

Electrospun fibers are widely used in composite material design and fabrication due to their high aspect ratio, high surface area and favorable mechanical properties. In this report, novel organic ionic plastic crystal (OIPC) modified poly(vinylidene difluoride) (PVDF) composite fiber membranes were prepared by electrospinning. These composite materials are of interest for application as solid electrolytes in devices including lithium and sodium batteries. The influence of the OIPC, N-ethyl-N-methylpyrrolidinium tetrafluoroborate [C2mpyr][BF4], on the morphology and phase behavior of the composite fibers was investigated by scanning electron microscopy and Fourier transform infrared spectroscopy. Compared with pure electrospun PVDF fibers, which have an electroactive β phase and a small amount of non-polar α phase, the ion-dipole interaction between OIPC and the polymer in the co-electrospun composite system can reduce the non-polar α phase PVDF, resulting in almost entirely electroactive β phase PVDF. Differential scanning calorimetry shows that the ion-dipole interaction between the OIPC and PVDF can also interrupt the crystalline structure of the OIPC. Solid state NMR analysis also reveals different molecular dynamics of the [C2mpyr][BF4] in co-electrospun fibers compared with pure OIPC. Thus, electrospun [C2mpyr][BF4]/PVDF composite fibers that combine both increased ionic conductivity and almost pure β phase PVDF are demonstrated.

Common structural basis for central nervous system drug design

The main theme of this thesis is that there is a common structural basis for drugs acting on the central nervous system (CNS), and that this concept may be used to design new CNS-active drugs which have greater specificity and hence less side-effects. To develop these ideas, the biological basis of how drugs modify CMS neurotransmission is described, and illustrated using dopaminergic pathways. An account is then given of the use of physicochemical concepts in contemporary drug design. The complete conformational analysis of several antipsychotic drugs is used to illustrate some of these techniques in the development of a model for antipsychotic drug action. After reviewing current structure-activity studies in several classes of CNS drugs (antipsychotics, anti-depressants, stimulants, hal1ucinogens, anticonvulsants and analgesics), a hypothesis for a common structural basis of CNS drug action is proposed- This is based on a topographical comparison of the X-ray structures of eight representative CNS-active drugs, and consists of three parts: 1.there is a common structural basis for the activity of many different CNS-active drug classes; 2. an aromatic ring and a nitrogen atom are the primary binding groups whose topographical arrangement is fundamental to the activity of these drug classes; 3. the nature and placement of secondary binding determines different classes of CNS drug activity. A four-Point model for this common structural basis is then defined using 14- CNS-active drug structures that include the original eight used in proposing the hypothesis. The coordinates of this model are: R1 (0. 3.5, 0), R2 (0, -3.5, O), N (4.8. -0.3, 1.4), and R3 (6.3, 1.3, 0), where R1 and R2 represent the point locations of a hydrophobic interaction of the common aromatic ring with a receptor, and R3 locates the receptor point for a hydrogen bond involving the common nitrogen, N. Extended structures were used to define the receptor points R1, R2 and R3, and the complete conformational space of each of the 14 molecules was considered. It is then shoun that the model may be used to predict whether a given structure is likely to show CNS activity: a search over 1,000 entries in the current Merck Index shows a high probability (82%) of CNS activity in compounds fitting the structural model. Analysis of CNS neurotransmitters and neuropeptides shows that these fit the common model well. Based on the available evidence supporting chemical evolution, protein evolution, and the evolution of neurotransmitter functions, it is surmised that the aromatic ring/nitrogen atom pharmacophore proposed in the common model supports the idea of the evolution of CNS receptors and their neurotransmitters, possibly from an aromatic amine or acety1cho1ine acting as a primaeval communicating molecule. The third point in the hypothesis trilogy is then addressed. The extensive conformation-activity analyses that have resulted in well-defined models for five separate CNS drug classes are used to map out the locations of secondary binding groups relative to the common model for anti-psychotics, antidepressants, analgesics, anticholinergics, and anticonvulsants. With this information, and knowledge derived from receptor-binding data, it is postulated that drugs having specified activity could be designed. In order to generate novel structures having a high probability of CNS-activity, a process of drug design is described in which known CNS structures are superimposed topographically using the common model as a template. Atoms regarded as superfluous may be selectively deleted and the required secondary binding groups added in predicted locations to give novel structures. It is concluded that this process provides the basis for the rational design of new lead compounds which could further be optimized for potent and specific CNS activity.

Altered images : the relations between design representations and design practice

As information systems move out of the office into the wider world and are merged with mobile appliances, buildings and even clothing, the representations traditionally used in any one discipline may not be adequate for understanding these new domains. Design representations are ‘ways of seeing and not seeing’. Despite the central role representations play in design, the information systems design community has little understanding of the relation, ideal or actual, between design practice and design representation. This paper reports on an extensive design case study that aims at increasing understanding of the nature and affordances of representations in the design process and argues for the need for information systems as a discipline to open up discussion of the design representations that may be required to effectively design systems that mix traditional IS with disciplines such as industrial design, architecture and fashion design.

The domain layer for mixed-initiative interaction in generative design

The design space exploration formalism has developed data structures and algorithms of sufficient complexity and scope to support conceptual layout, massing, and enclosure configurations. However, design remains a human enterprise. To support the user in designing with the formalism, we have developed an interaction model that addresses the interleaving of user actions with the formal operations of design space exploration. The central feature of our interaction model is the modeling of control based on mixed-initiative. Initiative is sometimes taken by the designer and sometimes by the formalism in working on a shared design task. The model comprises three layers, domain, task, and dialogue. In this paper we describe the formulation of the domain layer of our mixed-initiative interaction model for design space exploration. We present the view of the domain as understood in the formalism in terms of the three abstract concepts of state, move, and structure. In order to support mixed initiative, it is necessary to develop a shared view of the domain. The domain layer addresses this problem by mapping the designer's view onto the symbol substrate. First, we present the designer's view of the domain in terms of problems, solutions, choices, and history. Second, we show how this view is interleaved with the symbol-substrate through four domain layer constructs, problem state, solution state, choice, and exploration history. The domain layer presents a suitable foundation for integrating the role of the designer with a description formalism. It enables the designer to maintain exploration freedom in terms of formulating and reformulating problems, generating solutions, making choices, and navigating the history of exploration.

Defuturing an architecture of destruction: a reconciliation of Van Berkel and Bos to the new design philosophy of Tony Fry

For some time now Tony Fry has promoted the idea of 'The Sustainment', an idea that asserts a paradigm shift in attitudes to consumption. 'The Sustainment' recognises that increasingly human futures are products of self-determination and not chance. Fry’s hypothesis can be understood through his concept of Defuturing, a philosophy that questions the role of design and the responsibility of designers to facilitating the ability to sustain (Fry 1999).
Central to Fry’s philosophy is an awareness that it is in the best interests of designers and their clients, as inhabitants of cultures increasingly driven by technology, to be aware of the relationships between the products and theories of design and the processes and implications of technological change. This is an awareness that is central to the concepts, work, and methodologies of the ‘UN Studio’ of Van Berkel and Bos described and elaborated upon in Move – Imagination, Techniques, and Effects (Van Berkel & Bos 1999). Here, Ben Van Berkel defines the parameters and methodologies employed by UN Studio in an environment of technological and socio-economic change. The Dutch practice could be said to exemplify something of a zeitgeist in current architectural design that sees architects, as Van Berkel and Bos view them, as “fashion designers of the future, dressing events to come and holding up a mirror to the world (Van Berkel & Bos 1999, back cover).” It is a zeitgeist that Fry might see as aligned to the resilient hype of ‘new creativity’, ‘globalisation’ the ‘romance with technology’, and the vacuous-ness of the world of fashion. (Fry The Voice of Sustainment: on Design Intelligence 2005).
A source of breaking down such design propaganda is identified by Fry in the notion of ‘scenarios,’ which “provide a mechanism for politico-practice assemblage in which dialogues and narratives of change can be rehearsed in ways that enable participants to re-educate themselves via critical confrontations” (Fry The Voice of Sustainment: on Design Intelligence 2005). From such a perspective this paper aims to practically illustrate and ground the Defuturing of Fry by establishing a dialogue between his writings and the theories that have generated the architectural designs of Van Berkel and Bos and there UN Studio. This will be a ‘scenario’ that examines therefore an appropriation and transformation of the applied intellectual practice of Van Berkel and Bos. Through this confrontation we shall explore the question of why sustainability appears to be so low in the agenda of many pre-eminent contemporary architects, and how we might refocus therefore practice and theory on the ability to sustain.

Increasing central adiposity: the Nepean longitudinal study of young people aged 7-8 to 12-13y

BACKGROUND: Estimates of the prevalence of overweight and obesity in young people are typically based on body mass index (BMI). However, BMI may not indicate the level of central adiposity. Waist circumference has therefore been recommended to identify young people at risk of morbidity associated with central adiposity.

OBJECTIVE: To investigate (a) change in total and central adiposity between 7–8 and 12–13 y (b) agreement between classifying young people as overweight or obese based on total adiposity and central adiposity, and (c) risk factors associated with the development of total and central adiposity.

DESIGN: Anthropometric measurements were taken on 342 children in 1996/97 and 5 y later. Risk factors examined included birth weight, physical activity, TV viewing, pubertal status, parental adiposity, diet and socio-economic status.

RESULTS: Between 7–8 and 12–13 y indices of central adiposity increased more than total adiposity; waist circumference z-score increased by (means.d.) 0.740.92 and BMI z-score increased by 0.180.67. At 12–13 y there was moderate agreement between the two measures of adiposity (weighted kappa=0.64). However, waist circumference identified a greater number of young people as overweight or obese compared to BMI (41.2 vs 29.3%, P<0.001). Adiposity status at 7–8 y, maternal obesity, and pubertal stage were the strongest predictors of BMI status at 12–13 y. Risk factors associated with increased central adiposity were similar.

CONCLUSIONS: Overweight and obesity, as measured by waist circumference, is a bigger problem than is currently assessed by BMI. Targeting known risk factors for total adiposity may be an appropriate strategy for preventing increased central adiposity.

Altered images : the relations between design representations and design practice

As information systems move out of the office into the wider world and are merged with mobile appliances, buildings and even clothing, the representations traditionally used in any one discipline may not be adequate for understanding these new domains. Design representations are ‘ways of seeing and not seeing’. Despite the central role representations play in design, the information systems design community has little understanding of the relation, ideal or actual, between design practice and design representation. This paper reports on an extensive design case study that aims at increasing understanding of the nature and affordances of representations in the design process and argues for the need for information systems as a discipline to open up discussion of the design representations that may be required to effectively design systems that mix traditional IS with disciplines such as industrial design, architecture and fashion design.

Library learning space design : a good student fit

We are seeing a renewed interest nationally and internationally in the design and development of new learning environments. There is, at Deakin and more generally in the higher education sector, recognition that the students' experience of a flexible and supportive educational environment is central to excellent teaching and fosters student success. Recent Carrick Institute (now the Australian Learning and Teaching Council) grants have supported the need for a greater understanding of good practice, with workshops being held around the country.

The student experience is integral to planning the re-purposing of Library spaces at Deakin's two larger campuses, Waurn Ponds and Burwood. The physical spaces within the Library will be flexible and provide support for individual learning and study, group learning and discussion, with ubiquitous ICT access and assistance services readily accessible. The improvement to the amenities, including contemporary, wired casual spaces, will encourage students to come on to campus and stay, strengthening opportunities to build a learning community. This learning community can extend through opportunities for social networking to students studying online and off-campus.

Library services and spaces will align with the new pedagogical needs of the university, providing holistic support for students' flexible learning experiences.
"We know that space can have a significant impact on teaching and learning . . . What we know about how people learn has changed our ideas about learning space. There is value from bumping into someone and having a casual conversation. There is value from hands on, active learning as well as from discussion and reflection. There is value in being able to receive immediate support when needed and from being able to integrate multiple activities [and multiple information sources] to complete a project." (Diane Oblinger, Learning Spaces, EDUCAUSE, 2006).

Supervisors are central to work characteristics affecting nurse outcomes

Purpose: To examine the predictive capability of the demand-control-support (DCS) model, augmented by organizational justice variables, on attitudinal- and health-related outcomes for nurses caring for elderly patients.

Design: The study is based on a cross-sectional survey design and involved 168 nurses working with elderly patients in facilities of a medium to large Australian organization.

Method: Participants were asked to complete a questionnaire consisting of scales designed for measuring independent (e.g., demand, control, support, organizational justice) and dependent (e.g., job satisfaction, organizational commitment, wellbeing and psychological distress) variables. Multiple regression analyses were undertaken to identify significant predictors of the outcome variables.

Findings: The DCS model explains the largest amount of variance across both the attitudinal and health outcomes with 27% of job satisfaction and 49% of organizational commitment, and 33% of psychological distress and 35% of wellbeing, respectively. Additional variance was explained by the justice variables for job satisfaction (5%), organizational commitment (4%), and psychological distress (23%).

Conclusions: Using organizational justice variables to augment the DCS model was valuable in better understanding the work conditions experienced by nurses caring for elderly patients. Inclusion of curvilinear effects added clarity to the potentially artifactual nature of certain interaction variables.

Clinical Relevance: The results indicated practical implications for managers of nurses caring for elderly patients in terms of developing and maintaining levels of job control, support, and fairness, as well as monitoring levels of job demands. The results particularly show the importance of nurses' immediate supervisors.

Addressing the contradiction between discourse and practice in health promotion

The main theme of this thesis is the contradiction between discourse and practice in health promotion. Many health promoters continue to exert power-over the community through top-down programming whilst at the same time using an emancipatory discourse. The thesis has addressed this contradiction in three parts. The first part determines how the emancipatroty discourse has evolved and eplores the role of social movements in the development of contemporary health discourses and their influence on the legitimisation of empowerment. Central to this discourse is the empowerment of communities. To understand the role of this concept the thesis provides an interpretation of the different meanings of power and community, and the different levels of analysis of empowerment in the context of health promotion programming. The second part identifies the nature of health programming and the dominance of top-down, and to a much lesser extent, bottom-up approaches. The thesis argues that these two approaches are not, and do not have to be, mutually exclusive. To address this issue the thesis presents a new methodology is situated within a framework developed for the accomodation of empowerment goals within health promotion programmes. The study also identifies the organisational areas of influence on the processs of community empowerment and it is these which are used for the assessment of this concept. Both the framework and the methodology address the contradiction in health promotion by making community empowerment operational within a programme context. The third part of the thesis supports the rationale for the design of the methodology with field work in rural Fijian communities. The findings are presented as a composite case study to highlight the experiences of implementing the methodolgy and the main themes that emerged during the field work. the final chapter of the thesis brings together the central themes of the study and draws from these and 'emergent agenda' as a way forward for health promotion research and practice.