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Bredin A.,Curtin University Australia | Mullins B.J.,Curtin University Australia | Mullins B.J.,Curtin Health Innovation Research Institute
Separation and Purification Technology | Year: 2012

This study investigated the influence of flow interruptions on the filtration performance of two different multi-layered fibrous filters during liquid aerosol filtration. It was found that both types of filters experienced a significant secondary loading stage, though they had reached a steady state for continuous flow. The filters showed distinctive increases in pressure drop and filter saturation until a second equilibrium state was reached. This second equilibrium state was attributed to a rearrangement of liquid in the filter during the breaks, clogging previously free passages. The ratio of shear and capillary forces was found to determine whether these passages were able to be "cleaned" once airflow was recommenced. Based on these findings, the airflow required to clean fully saturated filters was investigated and a phenomenological model developed to describe this behaviour. Furthermore, it was found that filters could be cleaned and reused, whereby they would return to one of the previous steady states (continuous or discontinuous flow). The experiments conducted in this work represent a more realistic test for oil-mist (or coalescing) filters than typical laboratory testing. Furthermore, it is hoped that they will help to bridge the gap between laboratory and field test results. © 2012 Elsevier B.V. All rights reserved. Source

Ferrari P.,University of Western Australia | Kulkarni H.,University of Western Australia | Dheda S.,University of Western Australia | Betti S.,University of Western Australia | And 5 more authors.
Clinical Journal of the American Society of Nephrology | Year: 2011

Background and objectives: Iron (Fe) overload may complicate parenteral Fe therapy used to enhance the efficacy of erythropoietic-stimulating agents in the treatment of anemia of chronic kidney disease. However, serum Fe markers are influenced by inflammation or malignancy and may not accurately reflect the amount of body Fe. Design, setting, participants, & measurements: We studied the relationship between parenteral Fe therapy, conventional serum Fe markers, and liver iron concentration (LIC) measured using magnetic resonance R2 relaxometry (FerriScan) in 25 Fe-deficient predialysis chronic kidney disease patients before and 2 and 12 weeks after single high-dose intravenous Fe and in 15 chronic hemodialysis patients with elevated serum ferritin (>500 μg/L). Results: In predialysis patients, there was strong dose dependency between the administered Fe dose and changes in LIC at weeks 2 and 12; however, no dose dependency between Fe dose and changes in ferritin or transferrin saturation (TSAT) were observed. In hemodialysis patients, LIC correlated with the cumulative Fe dose and duration of dialysis but not with current ferritin or TSAT. The cumulative Fe dose remained a significant independent predictor of LIC in a multiple regression model. Two dialysis patients who received >6 g parenteral Fe had substantially elevated LIC >130 μmol/g, which is associated with hemochromatosis. Conclusions: In Fe-deficient predialysis patients, intravenous Fe therapy is associated with increases in LIC unrelated to changes in conventional Fe markers. In hemodialysis patients, TSAT and ferritin are poor indicators of body Fe load, and some patients have LICs similar to those found in hemochromatosis. Copyright © 2011 by the American Society of Nephrology. Source

Ahmad N.,National University of Malaysia | Amin M.C.I.M.,National University of Malaysia | Mahali S.M.,University of Malaysia, Terengganu | Ismail I.,National University of Malaysia | Chuang V.T.G.,Curtin Health Innovation Research Institute
Molecular Pharmaceutics | Year: 2014

Stimuli-responsive bacterial cellulose-g-poly-(acrylic acid) hydrogels were investigated for their potential use as an oral delivery system for proteins. These hydrogels were synthesized using electron beam irradiation without any cross-linking agents, thereby eliminating any potential toxic effects associated with cross-linkers. Bovine serum albumin (BSA), a model protein drug, was loaded into the hydrogels, and the release profile in simulated gastrointestinal fluids was investigated. Cumulative release of less than 10% in simulated gastric fluid (SGF) demonstrated the potential of these hydrogels to protect BSA from the acidic environment of the stomach. Subsequent conformational stability analyses of released BSA by SDS-PAGE, circular dichroism, and an esterase activity assay indicated that the structural integrity and bioactivity of BSA was maintained and preserved by the hydrogels. Furthermore, an increase in BSA penetration across intestinal mucosa tissue was observed in an ex vivo penetration experiment. Our fabricated hydrogels exhibited excellent cytocompatibility and showed no sign of toxicity, indicating the safety of these hydrogels for in vivo applications. © 2014 American Chemical Society. Source

Jiwa M.,Curtin Health Innovation Research Institute | Jiwa M.,Curtin University Australia | Dhaliwal S.,Curtin University Australia
Quality in Primary Care | Year: 2012

Background We aimed to explore if increasing the amount of relevant information relayed in referral letters between general practitioners (GPs) or family physicians and hospital specialists helps in the scheduling of appointments for patients. We report a before and after study comparing outcomes before and after the introduction of software to assist referral writing. Methods The participants were GPs and hospital specialists based in metropolitan Perth, Western Australia. The amount of relevant information in referral letters from GPs was assessed with reference to a published schedule three months before and four months after deploying interactive computerised Referral Writer software (RW). The longer period after deploying the RW was to allow GPs time to become iamiliar with the RW. The letters were scored by a researcher for the amount of relevant information included and then independently assessed by two specialists in each of six specialties to determine if they were able to decide which patients needed to be seen soonest and what was the most likely outcome of the specialist consultation. The actual diagnosis for each case was recorded later to assess if there was an association between the amount of relevant information relayed and the diagnosis of life limiting or other pathologies. Results Each GP referred 5.6 patients on average, range (1, 14) before the RW and 4.8 patients, range (0, 14) after the RW. The amount of relevant information in the letters improved substantially after the RW, mean difference 37%, 95% Confidence Interval 43-30%, P<0.001. For 91% of letters after the RW, both specialists in each specialty were confident or very confident that they had enough information to decide when the patient should come to their clinic; this had increased from 50% before the RW, P= 0.001. There was no association observed between the amount of relevant information relayed and the final diagnosis. Conclusion Standardising and using electronic communications to refer appears to facilitate rational scheduling of specialist appointments. Comprehensive referral may help to ensure that the right patients are seen by the specialist sooner rather than later. © 2012 Radcliffe Publishing. Source

Jiwa M.,Curtin University Australia | Spilsbury K.,Curtin University Australia | Duke J.,Curtin Health Innovation Research Institute
Annals of Pharmacotherapy | Year: 2010

BACKGROUND: Pharmacists in Australia are routinely asked to advise people with lower bowel symptoms. Clinical, demographic, and working environment parameters may affect whether appropriate referral for advanced care is advised by pharmacists. OBJECTIVE: To characterize how selected clinical, demographic, and working environment variables affect the likelihood of a pharmacist providing a referral for patients with lower bowel symptoms to consult a general practitioner, and to investigate factors associated with agreement with an expert panel and colorectal cancer guidelines. METHODS: Self-administered questionnaires were distributed to a random sample of 300 pharmacists in Western Australia. Vignettes were constructed around 6 clinical variables and pharmacists were asked to describe a referral pathway. Logistic regression was used to identify factors associated with odds of referral and agreement with an expert panel. RESULTS: One hundred sixty-seven completed surveys were returned, giving a response rate of 56%. The odds of referral to a general practitioner were mostly associated with presenting symptoms, although lower odds of referral were observed with increasing volumes of weekly prescriptions. The odds of pharmacists agreeing with the expert panel for an urgent referral were 70% (95% CI 50 to 80) lower for weight loss as the presenting symptom compared to rectal bleeding. The expert panel considered weight loss or rectal bleeding of 4 weeks' duration as meriting an urgent referral, but 63% and 30% of pharmacists, respectively, disagreed. In contrast to cancer guidelines, over 60% of respondents did not consider persistent diarrhea in a 65-year-old patient as a likely symptom of significant bowel pathology. CONCLUSIONS: In general, pharmacists' patterns of referral were influenced by clinical symptoms and not by demographic or working environment variables. They over-referred patients with diarrhea but under-referred those with weight loss and rectal bleeding, according to the expert panel. This is a cause for concern because any unexplained rectal bleeding should be referred for further investigation. Source

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