Light history-dependent respiration explains the hysteresis in the daily ecosystem metabolism of seagrass

Oxygen flux between aquatic ecosystems and the water column is a measure of ecosystem metabolism. However, the oxygen flux varies during the day in a “hysteretic” pattern: there is higher net oxygen production at a given irradiance in the morning than in the afternoon. In this study, we investigated the mechanism responsible for the hysteresis in oxygen flux by measuring the daily pattern of oxygen flux, light, and temperature in a seagrass ecosystem (Zostera muelleri in Swansea Shoals, Australia) at three depths. We hypothesised that the oxygen flux pattern could be due to diel variations in either gross primary production or respiration in response to light history or temperature. Hysteresis in oxygen flux was clearly observed at all three depths. We compared this data to mathematical models, and found that the modification of ecosystem respiration by light history is the best explanation for the hysteresis in oxygen flux. Light history-dependent respiration might be due to diel variations in seagrass respiration or the dependence of bacterial production on dissolved organic carbon exudates. Our results indicate that the daily variation in respiration rate may be as important as the daily changes of photosynthetic characteristics in determining the metabolic status of aquatic ecosystems.

Introducing Design History Lectures 2015

This compilation of slides from eleven lectures spans the core content themes about design history including: what, when, how, where, who, why, heritage and future history. Examples are drawn for these design disciplines: architecture, fashion, industrial design, interactive & visual design, interior design, and landscape architecture.

The Australian litigation landscape - Oral and Maxillofacial Surgery and general dentistry (oral surgery procedures): An analysis of litigation cases

Background: There are persistent concerns about litigation in the dental and medical professions. These concerns arise in a setting where general dentists are more frequently undertaking a wider range of oral surgery procedures, potentially increasing legal risk. Methods: Judicial cases dealing with medical negligence in the fields of general dentistry (oral surgery procedure) and Oral and Maxillofacial Surgery were located using the three main legal databases. Relevant cases were analysed to determine the procedures involved, the patients’ claims of injury, findings of negligence, and damages awarded. A thematic analysis of the cases was undertaken to determine trends. Results: Fifteen cases over a twenty-year period were located across almost all Australian jurisdictions (eight cases involved general dentists; seven cases involved Oral and Maxillofacial Surgeons). Eleven of the fifteen cases involved determinations of whether or not the practitioner had failed in their duty of care; negligence was found in six cases. Eleven of the fifteen cases related to molar extractions (eight specifically to third molar). Conclusions: Dental and medical practitioners wanting to manage legal risk should have regard to circumstances arising in judicial cases. Adequate warning of risks is critical, as is offering referral in appropriate cases. Pre-operative radiographs, good medical records, and processes to ensure appropriate follow-up are also important.

Landscape Architecture History Seminar Notes 2015

These notes cover landscape design from ancient times to the early 20th century and were compiled from seminars delivered by the author for the DEB202 Introducing Design History unit at QUT.

The potential for production of freeze-dried oral vaccines using alginate hydrogel microspheres as protein carriers

Oral administration of dry vaccine formulations is acknowledged to offer major clinical and logistical benefits by eliminating the cold chain required for liquid preparations. A model antigen, bovine serum albumin (BSA) was encapsulated in alginate microspheres using aerosolisation. Hydrated microspheres 25 to 65 μm in size with protein loading of 3.3 % w/w were obtained. Environmental scanning electron microscopy indicated a stabilizing effect of encapsulated protein on alginate hydrogels revealed by an increase in dehydration resistance. Freeze drying of alginate microspheres without use of a cryoprotectant resulted in fragmentation and subsequent rapid loss of the majority of the protein load in simulated intestinal fluid in 2 h, whereas intact microspheres were observed following freeze-drying of BSA-loaded microspheres in the presence of maltodextrin. BSA release from freeze-dried preparations was limited to less than 7 % in simulated gastric fluid over 2 h, while 90 % of the protein load was gradually released in simulated intestinal fluid over 10 h. SDS-PAGE analysis indicated that released BSA largely preserved its molecular weight. These findings demonstrate the potential for manufacturing freeze-dried oral vaccines using alginate microspheres.

Impulsivity-related cognition in alcohol dependence: Is it moderated by DRD2/ANKK1 gene status and executive dysfunction?

Perceived impaired control over alcohol use is a key cognitive construct in alcohol dependence that has been related prospectively to treatment outcome and may mediate the risk for problem drinking conveyed by impulsivity in non-dependent drinkers. The aim of the current study was to investigate whether perceived impaired control may mediate the association between impulsivity-related measures (derived from the Short-form Eysenck Personality Questionnaire-Revised) and alcohol-dependence severity in alcohol-dependent drinkers. Furthermore, the extent to which this hypothesized relationship was moderated by genetic risk (Taq1A polymorphism in the DRD2/ANKK1 gene cluster) and verbal fluency as an indicator of executive cognitive ability (Controlled Oral Word Association Test) was also examined. A sample of 143 alcohol-dependent inpatients provided an extensive clinical history of their alcohol use, gave 10ml of blood for DNA analysis, and completed self-report measures relating to impulsivity, impaired control and severity of dependence. As hypothesized, perceived impaired control (partially) mediated the association between impulsivity-related measures and alcohol-dependence severity. This relationship was not moderated by the DRD2/ANKK1 polymorphism or verbal fluency. These results suggest that, in alcohol dependence, perceived impaired control is a cognitive mediator of impulsivity-related constructs that may be unaffected by DRD2/ANKK1 and neurocognitive processes underlying the retrieval of verbal information

Plantar pressure in diabetic peripheral neuropathy patients with active foot ulceration, previous ulceration and no history of ulceration: A meta-analysis of observational studies

Aims Elevated dynamic plantar pressures are a consistent finding in diabetes patients with peripheral neuropathy with implications for plantar foot ulceration. This meta-analysis aimed to compare the plantar pressures of diabetes patients that had peripheral neuropathy and those with neuropathy with active or previous foot ulcers. Methods Published articles were identified from Medline via OVID, CINAHL, SCOPUS, INFORMIT, Cochrane Central EMBASE via OVID and Web of Science via ISI Web of Knowledge bibliographic databases. Observational studies reporting barefoot dynamic plantar pressure in adults with diabetic peripheral neuropathy, where at least one group had a history of plantar foot ulcers were included. Interventional studies, shod plantar pressure studies and studies not published in English were excluded. Overall mean peak plantar pressure (MPP) and pressure time integral (PTI) were primary outcomes. The six secondary outcomes were MPP and PTI at the rear foot, mid foot and fore foot. The protocol of the meta-analysis was published with PROPSERO, (registration number CRD42013004310). Results Eight observational studies were included. Overall MPP and PTI were greater in diabetic peripheral neuropathy patients with foot ulceration compared to those without ulceration (standardised mean difference 0.551, 95% CI 0.290–0.811, p<0.001; and 0.762, 95% CI 0.303–1.221, p = 0.001, respectively). Sub-group analyses demonstrated no significant difference in MPP for those with neuropathy with active ulceration compared to those without ulcers. A significant difference in MPP was found for those with neuropathy with a past history of ulceration compared to those without ulcers; (0.467, 95% CI 0.181– 0.753, p = 0.001). Statistical heterogeneity between studies was moderate. Conclusions Plantar pressures appear to be significantly higher in patients with diabetic peripheral neuropathy with a history of foot ulceration compared to those with diabetic neuropathy without a history of ulceration. More homogenous data is needed to confirm these findings.

Comparison of oropharyngeal and oral cavity squamous cell cancer incidence and trends in New Zealand and Queensland, Australia

Background Increases in the incidence of squamous cell oropharyngeal cancer (OPC) have been reported from some countries, but have not been assessed in Australia or New Zealand. This study examines trends for squamous cell OPC and squamous cell oral cavity cancer (OCC) in two similarly sized populations, New Zealand and Queensland, Australia. Methods Incidence data for 1982–2010 were obtained from the respective population-based cancer registries for squamous cell OPC and OCC, by subsite, sex, and age. Time trends and annual percentage changes (APCs) were assessed by joinpoint regression. Results The incidence rates of squamous cell OPC in males in New Zealand since 2005 and Queensland since 2006 have increased rapidly, with APCs of 11.9% and 10.6% respectively. The trends were greatest at ages 50–69 and followed more gradual increases previously. In females, rates increased by 2.1% per year in New Zealand from 1982, but by only 0.9% (not significant) in Queensland. In contrast, incidence rates for OCC decreased by 1.2% per year in males in Queensland since 1982, but remained stable for females in Queensland and for both sexes in New Zealand. Overall, incidence rates for both OCC and OPC were substantially higher in Queensland than in New Zealand. In males in both areas, OPC incidence is now higher than that of OCC. Conclusions Incidence rates of squamous cell OPC have increased rapidly in men, while rates of OCC have been stable or reducing, showing distinct etiologies. This has both clinical and public health importance, including implications for the extension of human papilloma virus (HPV) vaccination to males.

Australia's disabling income support system: Tracing the history of the disability pension from 1908 to today

This article is based on a historical-comparative policy and discourse analysis of the principles underpinning the Australian disability income support system. It determines that these principles rely on a conception of disability that sustains a system of coercion and paternalism that perpetuates disability and referred to as disablism. The article examines the construction of disability in Australian income support across four major historical epochs spanning the period 1908-2007. Contextualisation of the policy trajectory and discourses of the contemporary disability pension regime for the time period 2008-now is also provided. Two major themes were found to have interacted with the ideology of disablism. This article argues that a non-disabling provision based on social citizenship, rather than responsible or productive citizenship, counters the tendency for authoritarian and paternal approaches. [Abridged]

The in vivo fate of nanoparticles and nanoparticle-loaded microcapsules after oral administration in mice: Evaluation of their potential for colon-specific delivery

Anti-cancer drug loaded-nanoparticles (NPs) or encapsulation of NPs in colon-targeted delivery systems shows potential for increasing the local drug concentration in the colon leading to improved treatment of colorectal cancer. To investigate the potential of the NP-based strategies for colon-specific delivery, two formulations, free Eudragit® NPs and enteric-coated NP-loaded chitosan–hypromellose microcapsules (MCs) were fluorescently-labelled and their tissue distribution in mice after oral administration was monitored by multispectral small animal imaging. The free NPs showed a shorter transit time throughout the mouse digestive tract than the MCs, with extensive excretion of NPs in faeces at 5 h. Conversely, the MCs showed complete NP release in the lower region of the mouse small intestine at 8 h post-administration. Overall, the encapsulation of NPs in MCs resulted in a higher colonic NP intensity from 8 h to 24 h post-administration compared to the free NPs, due to a NP ‘guarding’ effect of MCs during their transit along mouse gastrointestinal tract which decreased NP excretion in faeces. These imaging data revealed that this widely-utilised colon-targeting MC formulation lacked site-precision for releasing its NP load in the colon, but the increased residence time of the NPs in the lower gastrointestinal tract suggests that it is still useful for localised release of chemotherapeutics, compared to NP administration alone. In addition, both formulations resided in the stomach of mice at considerable concentrations over 24 h. Thus, adhesion of NP- or MC-based oral delivery systems to gastric mucosa may be problematic for colon-specific delivery of the cargo to the colon and should be carefully investigated for a full evaluation of particulate delivery systems.

Prevalence and risk factors for oral HPV infection in young Australians

The prevalence of human papillomavirus (HPV)–associated head and neck cancers is increasing, but the prevalence of oral HPV infection in the wider community remains unknown. We sought to determine the prevalence of, and identify risk factors for, oral HPV infection in a sample of young, healthy Australians. For this study, we recruited 307 Australian university students (18–35 years). Participants reported anonymously about basic characteristics, sexual behaviour, and alcohol, tobacco and illicit drugs use. We collected oral rinse samples from all participants for HPV testing and typing. Seven of 307 (2.3%) students tested positive for oral HPV infection (3 HPV-18, one each of HPV-16, -67, -69, -90), and six of them were males (p = 0.008). Compared to HPV negative students, those with oral HPV infection were more likely to have received oral sex from more partners in their lifetime (p = 0.0004) and in the last year (p = 0.008). We found no statistically significant associations with alcohol consumption, smoking or numbers of partners for passionate kissing or sexual intercourse. In conclusion, oral HPV infection was associated with male gender and receiving oral sex in our sample of young Australians.

Studies of water and electrolyte movement from oral rehydration solutions (rice- and glucose-based) across a normal and secreting gut using a dual isotope tracer technique in a rat perfusion model

Aims: To establish a model to measure bidirectional flow of water from a glucose oral rehydration solution (G-ORS) and a newly developed rice-based oral rehydration solution (R-ORS) using a dual isotope tracer technique in a rat perfusion model. To measure net water, sodium and potassium absorption from the ORS. Methods: In viva steady-state perfusion studies were carried out in normal and secreting (induced by cholera toxin) rat small intestine (n = 11 in each group). To determine bidirectional flow of water from the ORS the animals were initially labelled with tritium, and deuterium was added to the perfusion solution. Sequential perfusate and blood samples were collected after attainment of steady-state conditions and analysed for water and electrolyte content. Results: There was a significant increase in net water absorption from the R-ORS compared to the G-ORS in both the normal (P < 0.02) and secreting intestine (P < 0.05). Water efflux was significantly reduced in the R-ORS group compared to the G-ORS group in both the normal (P < 0.01) and the secreting intestine (P < 0.01). There was an increase in sodium absorption in the R-ORS group compared to the G-ORS. The G-ORS produced a significantly greater blood glucose level at 75 min compared to the R-ORS (P < 0.03) in the secreting intestine. Conclusions: This study demonstrates the improved water absorption from a rice-based ORS in both the normal and secreting intestine. Evidence that the absorption of water may be influenced by the osmolality of the ORS was also demonstrated.

A controlled trial comparing the efficacy of rice-based and hypotonic glucose oral rehydration solutions in infants and young children with gastroenteritis

A prospective randomized trial was conducted to compare the efficacy of a rice-based oral rehydration solution (ORS) with glucose ORS in infants and children under 5 years of age with acute diarrhoea and mild to moderate dehydration (<10%). One hundred children presenting to a large metropolitan teaching hospital were eligible for entry to the study and were randomized to receive rice ORS or glucose ORS. Outcome measures were stool output (SO), duration of illness (DD) and recovery time to introduction of other fluids (RTF) and diet (RTD). Significant differences were found for all outcome measures in favour of the rice ORS group. Mean SO was lower (160 vs 213 mt; P<0.02), mean DD was reduced (17.3 vs 24.3 h; P = 0.03) and median RTF was decreased (12.7 vs 18.1 h; P< 0.001) in the rice ORS group compared with the glucose ORS group. The median rime to introduction of diet and mean length of hospital stay showed similar significant reductions. Our study has shown rice ORS to be an acceptable alternative to glucose ORS in young children and have shown that it is significantly more effective in reducing the course of diarrhoeal illness and the time taken to return to normal drinking and eating habits.