Effect of defects on fracture strength of graphene sheets

With a hexagonal monolayer network of carbon atoms, graphene has demonstrated exceptional electrical 22 and mechanical properties. In this work, the fracture of graphene sheets with Stone–Wales type defects and vacancies were investigated using molecular dynamics simulations at different temperatures. The initiation of defects via bond rotation was also investigated. The results indicate that the defects and vacancies can cause significant strength loss in graphene. The fracture strength of graphene is also affected by temperature and loading directions. The simulation results were compared with the prediction from the quantized fracture mechanics.

Structural layers of communication on Twitter

Twitter is used for a range of communicative purposes. These extend from personal tweets that address what used to be Twitter’s default question, “What’s happening?”, through one-on-one @reply conversations between close friends and attempts at getting the attention of celebrities and other public actors, to discussions in communities built around specific issues—and back again to broadcast-style statements from well-known individuals and brands to their potentially very large retinue of followers.

The power of hands-on exercises in SCADA cyber security education

For decades Supervisory Control and Data Acquisition (SCADA) and Industrial Control Systems (ICS) have used computers to monitor and control physical processes in many critical industries, including electricity generation, gas pipelines, water distribution, waste treatment, communications and transportation. Increasingly these systems are interconnected with corporate networks via the Internet, making them vulnerable and exposed to the same risks as those experiencing cyber-attacks on a conventional network. Very often SCADA networks services are viewed as a specialty subject, more relevant to engineers than standard IT personnel. Educators from two Australian universities have recognised these cultural issues and highlighted the gap between specialists with SCADA systems engineering skills and the specialists in network security with IT background. This paper describes a learning approach designed to help students to bridge this gap, gain theoretical knowledge of SCADA systems' vulnerabilities to cyber-attacks via experiential learning and acquire practical skills through actively participating in hands-on exercises.

The effect of nitroxides on swarming motility and biofilms, multicellular behaviors in Pseudomonas aeruginosa

The ability of NO to induce biofilm dispersion has been well established. Here we investigated the effect of nitroxides (sterically hindered nitric oxide analogues) on biofilm formation and swarming motility in Pseudomonas aeruginosa. A transposon mutant unable to produce nitric oxide endogenously (nirS) was deficient in swarming motility relative to wild type and the complemented strain. Moreover, expression of the nirS gene was up-regulated by 9.65-fold in wild type swarming cells when compared to planktonic cells. Wild type swarming levels were substantially restored upon exogenous addition of nitroxide containing compounds, consistent with the hypothesis that NO is necessary for swarming motility. Here, we showed that nitroxides not only mimicked the dispersal activity of NO, but also prevented biofilms from forming in flow cell chambers. In addition, a nirS transposon mutant was deficient in biofilm formation relative to wild type and the complemented strain, thus implicating NO in the formation of biofilms. Intriguingly despite its stand alone action in inhibiting biofilm formation and promoting dispersal, a nitroxide partially restored the ability of a nirS mutant to form biofilms.

The effect of hypoxia on the stemness and differentiation capacity of PDLC and DPC

Introduction. Stem cells are regularly cultured under normoxic conditions. However, the physiological oxygen tension in the stem cell niche is known to be as low as 1-2% oxygen, suggesting that hypoxia has a distinct impact on stem cell maintenance. Periodontal ligament cells (PDLCs) and dental pulp cells (DPCs) are attractive candidates in dental tissue regeneration. It is of great interest to know whether hypoxia plays a role in maintaining the stemness and differentiation capacity of PDLCs and DPCs. Methods. PDLCs and DPCs were cultured either in normoxia (20% O2) or hypoxia (2% O2). Cell viability assays were performed and the expressions of pluripotency markers (Oct-4, Sox2, and c-Myc) were detected by qRT-PCR and western blotting. Mineralization, glycosaminoglycan (GAG) deposition, and lipid droplets formation were assessed by Alizarin red S, Safranin O, and Oil red O staining, respectively. Results. Hypoxia did not show negative effects on the proliferation of PDLCs and DPCs. The pluripotency markers and differentiation potentials of PDLCs and DPCs significantly increased in response to hypoxic environment. Conclusions. Our findings suggest that hypoxia plays an important role in maintaining the stemness and differentiation capacity of PDLCs and DPCs.

The impact of heatwaves on mortality and emergency hospital admissions from non-external causes in Brisbane, Australia

Objectives Heatwaves can have significant health consequences resulting in increased mortality and morbidity. However, their impact on people living in tropical/subtropical regions remains largely unknown. This study assessed the impact of heatwaves on mortality and emergency hospital admissions (EHAs) from non-external causes (NEC) in Brisbane, a subtropical city in Australia. Methods We acquired daily data on weather, air pollution and EHAs for patients aged 15 years and over in Brisbane between January 1996 and December 2005, and on mortality between January 1996 and November 2004. A locally derived definition of heatwave (daily maximum ≥37°C for 2 or more consecutive days) was adopted. Case–crossover analyses were used to assess the impact of heatwaves on cause-specific mortality and EHAs. Results During heatwaves, there was a statistically significant increase in NEC mortality (OR 1.46; 95% CI 1.21 to 1.77), cardiovascular mortality (OR 1.89; 95% CI 1.44 to 2.48), diabetes mortality in those aged 75+ (OR 9.96; 95% CI 1.02 to 96.85), NEC EHAs (OR 1.15; 95% CI 1.07 to 1.23) and EHAs from renal diseases (OR 1.41; 95% CI 1.09 to 1.83). The elderly were found to be particularly vulnerable to heatwaves (eg, for NEC EHAs, OR 1.24 for 65–74-year-olds and 1.39 for those aged 75+). Conclusions Significant increases in NEC mortality and EHAs were observed during heatwaves in Brisbane where people are well accustomed to hot summer weather. The most vulnerable were the elderly and people with cardiovascular, renal or diabetic disease.

Incidental treatment effects of CBT on suicidal ideation and hopelessness

Background: Depression and alcohol misuse are among the most prevalent diagnoses in suicide fatalities. The risk posed by these disorders is exacerbated when they co-occur. Limited research has evaluated the effectiveness of common depression and alcohol treatments for the reduction of suicide vulnerability in individuals experiencing comorbidity. Methods: Participants with depressive symptoms and hazardous alcohol use were selected from two randomised controlled trials. They had received either a brief (1 session) intervention, or depression-focused cognitive behaviour therapy (CBT), alcohol-focused CBT, therapist-delivered integrated CBT, computer-delivered integrated CBT or person-centred therapy (PCT) over a 10-week period. Suicidal ideation, hopelessness, depression severity and alcohol consumption were assessed at baseline and 12-month follow-up. Results: Three hundred three participants were assessed at baseline and 12 months. Both suicidal ideation and hopelessness were associated with higher severity of depressive symptoms, but not with alcohol consumption. Suicidal ideation did not improve significantly at follow-up, with no differences between treatment conditions. Improvements in hopelessness differed between treatment conditions; hopelessness improved more in the CBT conditions compared to PCT and in single-focused CBT compared to integrated CBT. Limitations: Low retention rates may have impacted on the reliability of our findings. Combining data from two studies may have resulted in heterogeneity of samples between conditions. Conclusions: CBT appears to be associated with reductions in hopelessness in people with co-occurring depression and alcohol misuse, even when it is not the focus of treatment. Less consistent results were observed for suicidal ideation. Establishing specific procedures or therapeutic content for clinicians to monitor these outcomes may result in better management of individuals with higher vulnerability for suicide.

A multilevel investigation into the effects of the philosophical community of inquiry on 6th grade students' reading comprehension, interest in maths, self-esteem, pro-social behaviours and emotional well-being

This investigation measured the effects of a one year participation in an Australian Philosophical Community of Inquiry program on 280 sixth grade students' reading comprehension, interest in maths, self-esteem, social behaviours, and emotional well-being. A multilevel model for change was used to detect differences in the response variables, between a quasi-experimental group and comparison group. Results showed that, for participants, reading comprehension significantly increased while interest in maths decreased. No differences between the groups were found for pro-social behaviour and emotional well-being. Self esteem, however, declined for participants while nonparticipants' self esteem increased.

Effect of ramipril on walking times and quality of life among patients with peripheral artery disease and intermittent claudication : a randomized controlled trial

Importance Approximately one-third of patients with peripheral artery disease experience intermittent claudication, with consequent loss of quality of life. Objective To determine the efficacy of ramipril for improving walking ability, patient-perceived walking performance, and quality of life in patients with claudication. Design, Setting, and Patients Randomized, double-blind, placebo-controlled trial conducted among 212 patients with peripheral artery disease (mean age, 65.5 [SD, 6.2] years), initiated in May 2008 and completed in August 2011 and conducted at 3 hospitals in Australia. Intervention Patients were randomized to receive 10 mg/d of ramipril (n = 106) or matching placebo (n = 106) for 24 weeks. Main Outcome Measures Maximum and pain-free walking times were recorded during a standard treadmill test. The Walking Impairment Questionnaire (WIQ) and Short-Form 36 Health Survey (SF-36) were used to assess walking ability and quality of life, respectively. Results At 6 months, relative to placebo, ramipril was associated with a 75-second (95% CI, 60-89 seconds) increase in mean pain-free walking time (P < .001) and a 255-second (95% CI, 215-295 seconds) increase in maximum walking time (P < .001). Relative to placebo, ramipril improved the WIQ median distance score by 13.8 (Hodges-Lehmann 95% CI, 12.2-15.5), speed score by 13.3 (95% CI, 11.9-15.2), and stair climbing score by 25.2 (95% CI, 25.1-29.4) (P < .001 for all). The overall SF-36 median Physical Component Summary score improved by 8.2 (Hodges-Lehmann 95% CI, 3.6-11.4; P = .02) in the ramipril group relative to placebo. Ramipril did not affect the overall SF-36 median Mental Component Summary score. Conclusions and Relevance Among patients with intermittent claudication, 24-week treatment with ramipril resulted in significant increases in pain-free and maximum treadmill walking times compared with placebo. This was associated with a significant increase in the physical functioning component of the SF-36 score. Trial Registration clinicaltrials.gov Identifier: NCT00681226

Biocompatibility, SiH lenses and the impact of hydration on comfort

Silicone hydrogel (SiH) contact lenses have been available for over a decade. During that time, these highly innovative materials and designs have continually improved and now represent a major percentage of fits within the global contact lens market.1 Their high oxygen transmissibility has drastically reduced the incidence of hypoxia-related conditions such as corneal edema, limbal hyperaemia, and corneal vascularisation.2,3 However, there remain significant challenges in the quest for the ideal contact lens. The silicone material used in SiH contact lenses is inherently more hydrophobic than the non-silicone hydrogel materials. SiH lens manufacturers must find ways to overcome lens surface hydrophobicity since it can create issues in terms of lens wettability and surface deposition. Achieving ideal lens water content presents yet another challenge since increasing water content in a silicone hydrogel lens can reduce oxygen transmissibility. This is because increasing water content results in decreased silicone content in the lens and silicone is a better transmitter of oxygen than water.

The Deleuze Spray, New York 1977 : an Interview with Sanford Kwinter, Professor of Architectural Theory and Criticism at the Harvard Graduate School of Design, on the Architectural Reception of Gilles Deleuze in America

So what do you want to know? I was in Paris between ‘75 and ‘78. But about half way through, Sylvère published the Anti-Oedipus issue of Semiotext(e) and, actually, that was for me one of the deciding events that made me decide to come to the United States, to come study at Columbia University. There appeared to be this little group working at Columbia working around these issues. In 1970, in Paris even, Deleuze was a cult – there was an incredibly small number of people following Deleuze... A transcript of my Interview with Kwinter about the Architectural Reception of Deleuze in America, which took place at Jerry’s,' Soho, New York, 15 January 2003. The transcript appeared as an Appendix at the back of my Masters Thesis undertaken at Yale School of Architecture, printed May 2003.

The influence of teachers on students' decisions about choosing science : comparing student and teacher perceptions

This paper reports results from a study comparing teachers’ and students’ perceptions about the relative degree of influence parents, teachers, friends, older students and careers advisors have on students’ decisions about enrolling in non-compulsory high school science subjects. The comparison was carried out as part of the Choosing Science project - a large-scale Australian study of 15 year-old students’ experiences of school science and intentions regarding further participation. The study found that students considered their science teachers to have had the greatest influence, followed by parents and then friends. In contrast, however, science teachers believed their students to be most influenced in their decisions by friends and peers, followed by older students and siblings and parents, with teachers themselves having relatively little influence. Both groups believed that advice from careers advisors was of little influence. The findings are unique in the science education literature in providing an insight into differences and similarities in the perceptions of students and their teachers. In particular they indicate that teachers play a far greater role in students’ decisions about enrolling in science than they believe. This has important implications for science teachers and teacher educators in terms of appreciating their influence and applying it in ways that encourage participation in science courses.

Church's wall of silence on sexual abuse

A SINGLE document was all it took to illuminate a dark secret in the Church of England. The two-page child protection report, unearthed by police in the archives of the diocese of Manchester, was proof, at last, that a former cathedral choirboy -- alleging years of sexual abuse by one of Britain's most senior clergyman -- was not alone. There was another boy. Also a solo soprano, on the other side of the world, who was singing from the same hymn sheet about The Very Reverend Robert Waddington. "There had been a previous referral about sexual impropriety some time ago from Australia, where RW had been the headmaster at a school. An ex-pupil had made a complaint to the Bishop of (north) Queensland who had relayed it to the Archbishop (of York)," the 2003 report says. Eli Ward's family had prompted the secret report when they told church officials, without Ward's knowledge, of the alleged abuse he suffered in the mid-1980s.