Different correlation of Sphingosine-1-Phosphate receptor 1 with receptor activator of nuclear factor kappa B ligand and regulatory T cells in rat periapical lesions

Introduction Sphingosine-1-phosphate receptor 1 (S1P1) is crucial for regulation of immunity and bone metabolism. This study aimed to investigate the expression of S1P1 in rat periapical lesions and its relationship with receptor activator of nuclear factor kappa B ligand (RANKL) and regulatory T (Treg) cells. Methods Periapical lesions were induced by pulp exposure in the first lower molars of 55 Wistar rats. Thirty rats were killed on days 0, 7, 14, 21, 28, and 35, and their mandibles were harvested for x-ray imaging, micro–computed tomography scanning, histologic observation, immunohistochemistry, enzyme histochemistry, and double immunofluorescence analysis. The remaining 25 rats were killed on days 0, 14, 21, 28, and 35, and mandibles were harvested for flow cytometry. Results The volume and area of the periapical lesions increased from day 0 to day 21 and then remained comparably stable after day 28. S1P1-positive cells were observed in the inflammatory periapical regions; the number of S1P1-positive cells peaked at day 14 and then decreased from day 21 to day 35. The distribution of S1P1-positive cells was positively correlated with the dynamics of RANKL-positive cells but was negatively correlated with that of Treg cells. Conclusions S1P1 expression was differentially correlated with RANKL and Treg cell infiltration in the periapical lesions and is therefore a contributing factor to the pathogenesis of such lesions.

Pattern-based topic modelling and its application for information filtering and information retrieval

This thesis targets on a challenging issue that is to enhance users' experience over massive and overloaded web information. The novel pattern-based topic model proposed in this thesis can generate high-quality multi-topic user interest models technically by incorporating statistical topic modelling and pattern mining. We have successfully applied the pattern-based topic model to both fields of information filtering and information retrieval. The success of the proposed model in finding the most relevant information to users mainly comes from its precisely semantic representations to represent documents and also accurate classification of the topics at both document level and collection level.

A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: A systematic analysis for the Global Burden of Disease Study 2010

BACKGROUND Quantification of the disease burden caused by different risks informs prevention by providing an account of health loss different to that provided by a disease-by-disease analysis. No complete revision of global disease burden caused by risk factors has been done since a comparative risk assessment in 2000, and no previous analysis has assessed changes in burden attributable to risk factors over time. METHODS We estimated deaths and disability-adjusted life years (DALYs; sum of years lived with disability [YLD] and years of life lost [YLL]) attributable to the independent effects of 67 risk factors and clusters of risk factors for 21 regions in 1990 and 2010. We estimated exposure distributions for each year, region, sex, and age group, and relative risks per unit of exposure by systematically reviewing and synthesising published and unpublished data. We used these estimates, together with estimates of cause-specific deaths and DALYs from the Global Burden of Disease Study 2010, to calculate the burden attributable to each risk factor exposure compared with the theoretical-minimum-risk exposure. We incorporated uncertainty in disease burden, relative risks, and exposures into our estimates of attributable burden. FINDINGS In 2010, the three leading risk factors for global disease burden were high blood pressure (7·0% [95% uncertainty interval 6·2-7·7] of global DALYs), tobacco smoking including second-hand smoke (6·3% [5·5-7·0]), and alcohol use (5·5% [5·0-5·9]). In 1990, the leading risks were childhood underweight (7·9% [6·8-9·4]), household air pollution from solid fuels (HAP; 7·0% [5·6-8·3]), and tobacco smoking including second-hand smoke (6·1% [5·4-6·8]). Dietary risk factors and physical inactivity collectively accounted for 10·0% (95% UI 9·2-10·8) of global DALYs in 2010, with the most prominent dietary risks being diets low in fruits and those high in sodium. Several risks that primarily affect childhood communicable diseases, including unimproved water and sanitation and childhood micronutrient deficiencies, fell in rank between 1990 and 2010, with unimproved water and sanitation accounting for 0·9% (0·4-1·6) of global DALYs in 2010. However, in most of sub-Saharan Africa childhood underweight, HAP, and non-exclusive and discontinued breastfeeding were the leading risks in 2010, while HAP was the leading risk in south Asia. The leading risk factor in Eastern Europe, most of Latin America, and southern sub-Saharan Africa in 2010 was alcohol use; in most of Asia, North Africa and Middle East, and central Europe it was high blood pressure. Despite declines, tobacco smoking including second-hand smoke remained the leading risk in high-income north America and western Europe. High body-mass index has increased globally and it is the leading risk in Australasia and southern Latin America, and also ranks high in other high-income regions, North Africa and Middle East, and Oceania. INTERPRETATION Worldwide, the contribution of different risk factors to disease burden has changed substantially, with a shift away from risks for communicable diseases in children towards those for non-communicable diseases in adults. These changes are related to the ageing population, decreased mortality among children younger than 5 years, changes in cause-of-death composition, and changes in risk factor exposures. New evidence has led to changes in the magnitude of key risks including unimproved water and sanitation, vitamin A and zinc deficiencies, and ambient particulate matter pollution. The extent to which the epidemiological shift has occurred and what the leading risks currently are varies greatly across regions. In much of sub-Saharan Africa, the leading risks are still those associated with poverty and those that affect children.

The impact of simulated astigmatism on functional measures of visual performance

Uncorrected refractive error, including astigmatism, is a leading cause of reversible visual impairment. While the ability to perform vision-related daily activities is reduced when people are not optimally corrected, only limited research has investigated the impact of uncorrected astigmatism. Given the capacity to perform vision-related daily activities involves integration of a range of visual and cognitive cues, this research examined the impact of simulated astigmatism on visual tasks that also involved cognitive input. The research also examined whether the higher levels of complexity inherent in Chinese characters makes them more susceptible to the effects of astigmatism. The effects of different powers of astigmatism, as well as astigmatism at different axes were investigated in order to determine the minimum level of astigmatism that resulted in a decrement in visual performance.

Enhanced cortisol suppression following administration of low-dose dexamethasone in first-episode psychosis patients

OBJECTIVE Impaired regulation of the hypothalamic-pituitary-adrenal (HPA) axis and hyper-activity of this system have been described in patients with psychosis. Conversely, some psychiatric disorders such as post-traumatic stress disorder (PTSD) are characterised by HPA hypo-activity, which could be related to prior exposure to trauma. This study examined the cortisol response to the administration of low-dose dexamethasone in first-episode psychosis (FEP) patients and its relationship to childhood trauma. METHOD The low-dose (0.25 mg) Dexamethasone Suppression Test (DST) was performed in 21 neuroleptic-naive or minimally treated FEP patients and 20 healthy control participants. Childhood traumatic events were assessed in all participants using the Childhood Trauma Questionnaire (CTQ) and psychiatric symptoms were assessed in patients using standard rating scales. RESULTS FEP patients reported significantly higher rates of childhood trauma compared to controls (p = 0.001) and exhibited lower basal (a.m.) cortisol (p = 0.04) and an increased rate of cortisol hyper-suppression following dexamethasone administration compared to controls (33% (7/21) vs 5% (1/20), respectively; p = 0.04). There were no significant group differences in mean cortisol decline or percent cortisol suppression following the 0.25 mg DST. This study shows for the first time that a subset of patients experiencing their first episode of psychosis display enhanced cortisol suppression. CONCLUSIONS These findings suggest there may be distinct profiles of HPA axis dysfunction in psychosis which should be further explored.

Cortisol and dehydroepiandrosterone-sulphate levels correlate with symptom severity in first-episode psychosis

Dehydroepiandrosterone (DHEA) and its sulphate form (DHEA) are neuroactive steroids with antiglucocorticoid properties. An imbalance in the ratio of cortisol to DHEA(S) has been implicated in the pathophysiology of stress-related psychiatric disorders. This study prospectively investigated circulating cortisol, DHEAS and their ratio in first-episode psychosis (FEP) patients compared to healthy controls, and their relationship to perceived stress, psychotic, negative and mood symptoms. METHODS: Blood cortisol and DHEAS levels were obtained in 39 neuroleptic-naïve or minimally-treated FEP patients and 25 controls. Twenty-three patients and 15 controls received repeat assessments after 12 weeks. Perceived stress was assessed using the Perceived Stress Scale and symptoms were assessed in patients using standard rating scales. RESULTS: At baseline, no differences were observed in cortisol, DHEAS or the cortisol/DHEAS ratio between patients and controls. There were also no group differences in the change in these biological variables during the study period. Within FEP patients, decreases in cortisol and the cortisol/DHEAS ratio over time were directly related to the improvement in depression (r = 0.45; p = 0.031, r = 0.52; p = 0.01), negative (r = 0.51; p = 0.006, r = 0.55; p = 0.008) and psychotic symptoms (cortisol only, r = 0.53; p = 0.01). Perceived stress significantly correlated with DHEAS (r = 0.51; p = 0.019) and the cortisol/DHEAS ratio (r = -0.49; p = 0.024) in controls, but not patients, possibly reflecting an impaired hormonal response to stress in FEP patients. CONCLUSIONS: These findings further support the involvement of the stress system in the pathophysiology of psychotic disorders, with implications for treatment strategies that modulate these neurosteroids.

Relationship between vocational status and perceived stress and daily hassles in first-episode psychosis: An exploratory study

PURPOSE Vocational recovery is a primary treatment goal of young people with first-episode psychosis (FEP), yet treatment in this domain is often delayed due to concerns that it might be too stressful. This study aimed to examine whether a relationship exists between vocational status and level of perceived stress and daily hassles in FEP. METHODS Forty-seven FEP participants were recruited upon admission to the Early Psychosis Prevention and Intervention Centre (EPPIC), Melbourne. Demographics, psychopathology, perceived stress (Perceived Stress Scale; PSS) and daily hassles (Hassles Scale; HS) were measured. RESULTS Regarding vocational status, 19 participants were unemployed, 13 were employed, 14 were students, and 1 reported 'home duties'. ANOVAs and post hoc tests comparing the first three groups on perceived stress and daily hassles revealed that the mean PSS Total and mean PSS Distress scores of the employed group were significantly lower than those of the unemployed and student groups. Regarding hassles scores, the employed group had a significantly lower mean Hassles Intensity score than the unemployed group. Results were largely unchanged when covariates were included. There were no significant differences between the three groups in levels of anxiety, negative or positive symptoms. The employed group reported lower depression than the student group, but this finding disappeared after controlling for gender. CONCLUSIONS These results provide preliminary evidence supporting the notion that working or studying is not associated with increased perceived stress or daily hassles in FEP. The findings require replication in larger samples and in different phases of psychosis.

Projecting the new world city: The city as spectacle in an urban light festival

As a precursor to the 2014 G20 Leaders’ Summit held in Brisbane, Australia, the Queensland Government sponsored a program of G20 Cultural Celebrations, designed to showcase the Summit’s host city. The cultural program’s signature event was the Colour Me Brisbane festival, a two-week ‘citywide interactive light and projection installations’ festival that was originally slated to run from 24 October to 9 November, but which was extended due to popular demand to conclude with the G20 Summit itself on 16 November. The Colour Me Brisbane festival comprised a series projection displays that promoted visions of the city’s past, present, and future at landmark sites and iconic buildings throughout the city’s central business district and thus transformed key buildings into forms of media architecture. In some instances the media architecture installations were interactive, allowing the public to control aspects of the projections through a computer interface situated in front of the building; however, the majority of the installations were not interactive in this sense. The festival was supported by a website that included information regarding the different visual and interactive displays and links to social media to support public discussion regarding the festival (Queensland Government 2014). Festival-goers were also encouraged to follow a walking-tour map of the projection sites that would take them on a 2.5 kilometre walk from Brisbane’s cultural precinct, through the city centre, concluding at parliament house. In this paper, we investigate the Colour Me Brisbane festival and the broader G20 Cultural Celebrations as a form of strategic placemaking—designed, on the one hand, to promote Brisbane as a safe, open, and accessible city in line with the City Council’s plan to position Brisbane as a ‘New World City’ (Brisbane City Council 2014). On the other hand, it was deployed to counteract growing local concerns and tensions over the disruptive and politicised nature of the G20 Summit by engaging the public with the city prior to the heightened security and mobility restrictions of the Summit weekend. Harnessing perspectives from media architecture (Brynskov et al. 2013), urban imaginaries (Cinar & Bender 2007), and social media analysis, we take a critical approach to analysing the government-sponsored projections, which literally projected the city onto itself, and public responses to them via the official, and heavily promoted, social media hashtags (#colourmebrisbane and #g20cultural). Our critical framework extends the concepts of urban phantasmagoria and urban imaginaries into the emerging field of media architecture to scrutinise its potential for increased political and civic engagement. Walter Benjamin’s concept of phantasmagoria (Cohen 1989; Duarte, Firmino, & Crestani 2014) provides an understanding of urban space as spectacular projection, implicated in commodity and techno-culture. The concept of urban imaginaries (Cinar & Bender 2007; Kelley 2013)—that is, the ways in which citizens’ experiences of urban environments are transformed into symbolic representations through the use of imagination—similarly provides a useful framing device in thinking about the Colour Me Brisbane projections and their relation to the construction of place. Employing these critical frames enables us to examine the ways in which the installations open up the potential for multiple urban imaginaries—in the sense that they encourage civic engagement via a tangible and imaginative experience of urban space—while, at the same time, supporting a particular vision and way of experiencing the city, promoting a commodified, sanctioned form of urban imaginary. This paper aims to dissect the urban imaginaries intrinsic to the Colour Me Brisbane projections and to examine how those imaginaries were strategically deployed as place-making schemes that choreograph reflections about and engagement with the city.

GPU accelerated algorithms for computing matrix function vector products with applications to exponential integrators and fractional diffusion

The efficient computation of matrix function vector products has become an important area of research in recent times, driven in particular by two important applications: the numerical solution of fractional partial differential equations and the integration of large systems of ordinary differential equations. In this work we consider a problem that combines these two applications, in the form of a numerical solution algorithm for fractional reaction diffusion equations that after spatial discretisation, is advanced in time using the exponential Euler method. We focus on the efficient implementation of the algorithm on Graphics Processing Units (GPU), as we wish to make use of the increased computational power available with this hardware. We compute the matrix function vector products using the contour integration method in [N. Hale, N. Higham, and L. Trefethen. Computing Aα, log(A), and related matrix functions by contour integrals. SIAM J. Numer. Anal., 46(5):2505–2523, 2008]. Multiple levels of preconditioning are applied to reduce the GPU memory footprint and to further accelerate convergence. We also derive an error bound for the convergence of the contour integral method that allows us to pre-determine the appropriate number of quadrature points. Results are presented that demonstrate the effectiveness of the method for large two-dimensional problems, showing a speedup of more than an order of magnitude compared to a CPU-only implementation.

Managing knowledge to promote sustainability in Australian transport infrastructure projects

To deliver tangible sustainability outcomes, the infrastructure sector of the construction industry needs to build capacities for the creation, application and management of ever increasing knowledge. This paper intends to establish the importance and key issues of promoting sustainability through knowledge management (KM). It presents a new conceptual framework for managing sustainability knowledge to raise the awareness and direct future research in the field of transport infrastructure, one of the fast growing sectors in Australia. A holistic KM approach is adopted in this research to consider the potential to “deliver the right information to the right person at the right time” in the context of sustainable development of infrastructure. A questionnaire survey among practitioners across the nation confirmed the necessity and identified priority issues of managing knowledge for sustainability. During infrastructure development, KM can help build much needed industry consensus, develop capacity, communicate decisions, and promote specific measures for the pursuit of sustainability. Six essential elements of the KM approach and their priority issues informed the establishment of a conceptual KM framework. The transport infrastructure sector has come to realise that development must not come at the expense of environmental and social objectives. In practice however, it is facing extensive challenges to deliver what has been promised in the sustainability agenda. This research demonstrates the importance of managing sustainability knowledge, integration of various stakeholders, facilitation of plans and actions and delivery of tangible benefits in real projects, as a positive step towards meeting these challenges.

A comprehensive mechanistic kinetic model for dilute acid hydrolysis of switchgrass cellulose to glucose, 5-HMF and levulinic acid

Switchgrass was treated by 1% (w/w) H₂SO₄in batch tube reactors at temperatures ranging from 140–220°C for up to 60 minutes. In this study, release patterns of glucose, 5-hydroxymethylfurfural (5-HMF), and levulinic acid from switchgrass cellulose were investigated through a mechanistic kinetic model. The predictions were consistent with the measured products of interest when new parameters reflecting the effects of reaction limitations, such as cellulose crystallinity, acid soluble lignin–glucose complex (ASL–glucose) and humins that cannot be quantitatively analyzed, were included. The new mechanistic kinetic model incorporating these parameters simulated the experimental data with R² above 0.97. Results showed that glucose yield was most sensitive to variations in the parameter regarding the cellulose crystallinity at low temperatures (140–180°C), while the impact of crystallinity on the glucose yield became imperceptible at elevated temperatures (200–220 °C). Parameters related to the undesired products (e.g. ASL–glucose and humins) were the most sensitive factors compared with rate constants and other additional parameters in impacting the levulinic acid yield at elevated temperatures (200–220°C), while their impacts were negligible at 140–180°C. These new findings provide a more rational explanation for the kinetic changes in dilute acid pretreatment performance and suggest that the influences of cellulose crystallinity and undesired products including ASL–glucose and humins play key roles in determining the generation of glucose, 5-HMF and levulinic acid from biomass-derived cellulose.

Effect of covalent functionalisation on thermal transport across graphene-polymer interfaces

This paper is concerned with the interfacial thermal resistance for polymer composites reinforced by various covalently functionalised graphene. By using molecular dynamics simulations, the obtained results show that the covalent functionalisation in graphene plays a significant role in reducing the graphene-paraffin interfacial thermal resistance. This reduction is dependent on the coverage and type of functional groups. Among the various functional groups, butyl is found to be the most effective in reducing the interfacial thermal resistance, followed by methyl, phenyl and formyl. The other functional groups under consideration such as carboxyl, hydroxyl and amines are found to produce negligible reduction in the interfacial thermal resistance. For multilayer graphene with a layer number up to four, the interfacial thermal resistance is insensitive to the layer number. The effects of the different functional groups and the layer number on the interfacial thermal resistance are also elaborated using the vibrational density of states of the graphene and the paraffin matrix. The present findings provide useful guidelines in the application of functionalised graphene for practical thermal management.

Extending genetic linkage analysis to diffusion tensor images to map single gene effects on brain fiber architecture

We extended genetic linkage analysis - an analysis widely used in quantitative genetics - to 3D images to analyze single gene effects on brain fiber architecture. We collected 4 Tesla diffusion tensor images (DTI) and genotype data from 258 healthy adult twins and their non-twin siblings. After high-dimensional fluid registration, at each voxel we estimated the genetic linkage between the single nucleotide polymorphism (SNP), Val66Met (dbSNP number rs6265), of the BDNF gene (brain-derived neurotrophic factor) with fractional anisotropy (FA) derived from each subject's DTI scan, by fitting structural equation models (SEM) from quantitative genetics. We also examined how image filtering affects the effect sizes for genetic linkage by examining how the overall significance of voxelwise effects varied with respect to full width at half maximum (FWHM) of the Gaussian smoothing applied to the FA images. Raw FA maps with no smoothing yielded the greatest sensitivity to detect gene effects, when corrected for multiple comparisons using the false discovery rate (FDR) procedure. The BDNF polymorphism significantly contributed to the variation in FA in the posterior cingulate gyrus, where it accounted for around 90-95% of the total variance in FA. Our study generated the first maps to visualize the effect of the BDNF gene on brain fiber integrity, suggesting that common genetic variants may strongly determine white matter integrity.

Genetics of anisotropy asymmetry: Registration and sample size effects

Brain asymmetry has been a topic of interest for neuroscientists for many years. The advent of diffusion tensor imaging (DTI) allows researchers to extend the study of asymmetry to a microscopic scale by examining fiber integrity differences across hemispheres rather than the macroscopic differences in shape or structure volumes. Even so, the power to detect these microarchitectural differences depends on the sample size and how the brain images are registered and how many subjects are studied. We fluidly registered 4 Tesla DTI scans from 180 healthy adult twins (45 identical and fraternal pairs) to a geometrically-centered population mean template. We computed voxelwise maps of significant asymmetries (left/right hemisphere differences) for common fiber anisotropy indices (FA, GA). Quantitative genetic models revealed that 47-62% of the variance in asymmetry was due to genetic differences in the population. We studied how these heritability estimates varied with the type of registration target (T1- or T2-weighted) and with sample size. All methods consistently found that genetic factors strongly determined the lateralization of fiber anisotropy, facilitating the quest for specific genes that might influence brain asymmetry and fiber integrity.

Tensor-based analysis of genetic influences on brain integrity using DTI in 100 twins

Information from the full diffusion tensor (DT) was used to compute voxel-wise genetic contributions to brain fiber microstructure. First, we designed a new multivariate intraclass correlation formula in the log-Euclidean framework. We then analyzed used the full multivariate structure of the tensor in a multivariate version of a voxel-wise maximum-likelihood structural equation model (SEM) that computes the variance contributions in the DTs from genetic (A), common environmental (C) and unique environmental (E) factors. Our algorithm was tested on DT images from 25 identical and 25 fraternal twin pairs. After linear and fluid registration to a mean template, we computed the intraclass correlation and Falconer's heritability statistic for several scalar DT-derived measures and for the full multivariate tensors. Covariance matrices were found from the DTs, and inputted into SEM. Analyzing the full DT enhanced the detection of A and C effects. This approach should empower imaging genetics studies that use DTI.