Purification and characterization of naringinase from a newly isolated strain of Aspergillus niger 1344 for the transformation of flavonoids

An extracellular naringinase (an enzyme complex consisting of α-L-rhamnosidase and β-D-glucosidase activity, EC 3.2.1.40) that hydrolyses naringin (a trihydroxy flavonoid) for the production of rhamnose and glucose was purified from the culture filtrate of Aspergillus niger 1344. The enzyme was purified 38-fold by ammonium sulphate precipitation, ion exchange and gel filtration chromatography with an overall recovery of 19% with a specific activity of 867 units per mg of protein. The molecular mass of the purified enzyme was estimated to be about 168 kDa by gel filtration chromatography on a Sephadex G-200 column and the molecular mass of the subunits was estimated to be 85 kDa by sodium dodecyl sulphate-Polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme had an optimum pH of 4.0 and temperature of 50 °C, respectively. The naringinase was stable at 37 °C for 72 h, whereas at 40 °C the enzyme showed 50% inactivation after 96 h of incubation. Hg2+, SDS, p-chloromercuribenzoate, Cu2+ and Mn2+ completely inhibited the enzyme activity at a concentration of 2.5–10 mM, whereas, Ca2+, Co2+ and Mg2+ showed very little inactivation even at high concentrations (10–100 mM). The enzyme activity was strongly inhibited by rhamnose, the end product of naringin hydrolysis. The enzyme activity was accelerated by Mg2+ and remained stable for one year after storage at −20 °C. The purified enzyme preparation successfully hydrolysed naringin and rutin, but not hesperidin.

Investigation of overweight and obesity management in a rural primary health care setting

Background : The rural region of interest has one main central medical clinic and several smaller outlying clinics. The services available for weight management include dietetic services, community-based groups and bariatric surgery. At present, no formal area specific referral pathway exists for the treatment of overweight and obesity.
Aims & rationale/Objectives : To investigate general practitioners':
- assessment practices and experiences with overweight and obese clients
- experience of different treatment options for overweight and obesity
- perceived barriers to overweight and obesity management.
Methods : A self-administered survey will be sent to general practitioners within the region of interest. The survey was designed to investigate current methods of assessing overweight and obesity; treatment options; and perceived barriers to successful weight management. Participants will also be offered a brief interview to discuss the following topics; Usefulness of NHMRC's Overweight and Obesity Guidelines; barriers and frustrations of weight management, GP's and dietitian's roles in overweight and obesity treatment.
Principal findings : It is expected the principal findings will include details about methods used to determine overweight and obesity; factors considered when selecting patients for treatment; favoured treatment options of GPs; perceived barriers and frustrations of managing overweight and obese patients.
Discussion : Overweight and obesity are significant health issues in Australia, with recent data indicating more than 60% of Australian adults are affected (NHMRC, 2003). Studies have also suggested that the prevalence of overweight and obesity is higher in rural populations (Coulson, 2005). GPs have been recognised as an important contributor in the treatment of overweight and obesity (Campbell, 2000). There have been guidelines produced to assist GPs, however the extent to which guidelines are utilised or their perceived effectiveness have not yet been investigated.
Implications : It is thought that an investigation into current methods of assessing overweight and obesity; treatment options; and perceived barriers to successful weight management will provide valuable information to inform primary health care service provision and future quality improvement directions.
Presentation type : Poster
Session theme : Primary health care delivery

Electrostatic complex of didodecyldimethylammonium and DNA: Langmuir monolayer, Langmuir–Blodgett film and dye recognition at air/water interface

DNA–didodecyldimethylammonium (DNA–DDDA) electrostatic complex was prepared and characterized through Fourier transformation infrared (FT-IR), 1H NMR and circular dichroism (CD) spectroscopy. When the dye molecule aqueous solutions were used as the subphase, the interaction between three dye molecules, acridine orange (AO), ethidium bromide (EB) and 5,10,15,20-tetrakis(4-N-methylpyridyl)porphine tetra(p-toluenesulfonate) (TMPyP) and the complex at air/solution interface were investigated through the surface pressure–area (π–A) isotherms, Brewster angle microscopy and UV-Vis spectroscopy, respectively. Our investigation indicates that the interaction capabilities of the three dyes to DNA–DDDA complex are different and present an order of TMPyP>AO>EB. For the interaction forms, we believe that TMPyP intercalates into the double helix of DNA, and AO adsorbs onto the surface of the DNA. As for EB, the measured signal is too weak to give a definite interaction form in the present experiment.

Ethics, aesthetics and the transformation of the self : Foucault's practice of philosophy

Drawing in part on research carried out in the Foucault archives in Paris, the thesis both undertakes a critical assessment of Foucault's late work and attempts to reconstruct the ethical attitude which was emerging in that work. It situates Foucault's project in the context of its Nietzschean inspiration and offers a Foucauldian model of ethics as an aesthetic, transformative work carried out upon the self - as a 'spiritual exercise' in which the critical practice of philosophy takes a central role.

The relationship between characteristics of context and research utilization in a pediatric setting

Background
Research utilization investigators have called for more focused examination of the influence of context on research utilization behaviors. Yet, up until recently, lack of instrumentation to identify and quantify aspects of organizational context that are integral to research use has significantly hampered these efforts. The Alberta Context Tool (ACT) was developed to assess the relationships between organizational factors and research utilization by a variety of healthcare professional groups. The purpose of this paper is to present findings from a pilot study using the ACT to elicit pediatric and neonatal healthcare professionals' perceptions of the organizational context in which they work and their use of research to inform practice. Specifically, we report on the relationship between dimensions of context, founded on the Promoting Action on Research Implementation in Health Services (PARIHS) framework, and self-reported research use behavior.

Methods
A cross-sectional survey approach was employed using a version of the ACT, modified specifically for pediatric settings. The survey was administered to nurses working in three pediatric units in Alberta, Canada. Scores for three dimensions of context (culture, leadership and evaluation) were used to categorize respondent data into one of four context groups (high, moderately high, moderately low and low). We then examined the relationships between nurses` self-reported research use and their perceived context.

Results
A 69% response rate was achieved. Statistically significant differences in nurses' perceptions of culture, leadership and evaluation, and self-reported conceptual research use were found across the three units. Differences in instrumental research use across the three groups of nurses by unit were not significant. Higher self-reported instrumental and conceptual research use by all nurses in the sample was associated with more positive perceptions of their context.

Conclusions
Overall, the results of this study lend support to the view that more positive contexts are associated with higher reports of research use in practice. These findings have implications for organizational endeavors to promote evidence-informed practice and maximize the quality of care. Importantly, these findings can be used to guide the development of interventions to target modifiable characteristics of organizational context that are influential in shaping research use behavior.

Characterization of the bake-hardening behavior of transformation induced plasticity and dual-phase steels using advanced analytical techniques

The bake-hardening (BH) behavior of TRansformation Induced Plasticity (TRIP) and Dual-Phase (DP) steels after intercritical annealing (IA) has been studied using transmission electron microscopy, X-ray diffraction and three dimensional atom probe tomography. It was found for the DP steel that carbon can segregate to dislocations in the ferrite plastic deformation zones where there is a high dislocation density around the "asquenched" martensite. The carbon pinning of these dislocations, in turn, increases the yield strength after aging. It was shown that bake-hardening also leads to rearrangement of carbon in the martensite leading to the formation of rod-like low temperature carbides in the DP steel. Segregation of carbon to microtwins in retained austenite of the TRIP steel was also evident. These factors, in combination with the dislocation rearrangement in ferrite through the formation of cells and microbands in the TRIP steel after pre-straining, lead to the different bake-hardening responses of the two steels.

Kinetically controlled homogenization and transformation of crystalline fiber networks in supramolecular materials

Supramolecular materials with three-dimensional fiber networks have applications in many fields. For these applications, a homogeneous fiber network is essential in order to get the desired performance of a material. However, such a fiber network is hard to obtain, particularly when the crystallization of fiber takes place nonisothermally. In this work, a copolymer is used to kinetically control the nucleation and fiber network formation of a small molecular gelling agent, N-lauroyl-L-glutamic acid di-nbutylamide (GP-1) in benzyl benzoate. The retarded nucleation and enhanced mismatch nucleation of the gelator by the additive leads to the conversion of a mixed fiber network into a homogeneous network consisting of spherulites only. The enhanced structural mismatch of the GP-1 during crystallization is quantitatively characterized using the rheological data. This effect also leads to the transformation of an interconnecting (single) fiber network of GP-1 into a multidomain fiber network in another solvent, isostearyl alcohol. The approach developed is significant to the production of supramolecular materials with homogeneous fiber networks and is convenient to switch a single fiber network to a multidomain network without adjusting the thermodynamic driving force.