Maximal structuring of acyclic process models

This article addresses the transformation of a process model with an arbitrary topology into an equivalent structured process model. In particular, this article studies the subclass of process models that have no equivalent well-structured representation but which, nevertheless, can be partially structured into their maximally-structured representation. The transformations are performed under a behavioral equivalence notion that preserves the observed concurrency of tasks in equivalent process models. The article gives a full characterization of the subclass of acyclic process models that have no equivalent well-structured representation, but do have an equivalent maximally-structured one, as well as proposes a complete structuring method. Together with our previous results, this article completes the solution of the process model structuring problem for the class of acyclic process models.

Comparison of self-reported driving behaviours and experiences of immediate-uptake and delayed-uptake licence holders

The objective of this paper was to explore experiences of ‘immediate-uptake’ (intermediate licensure at age 17-18 years, n = 928) and ‘delayed-uptake’ (intermediate licensure at age 19-20 years, n = 158) driver’s licence holders in the Australian state of Queensland. In Queensland, the graduated driver licence program applies to all novices irrespective of age. Drivers who obtained a Provisional 1 (intermediate) (P1) licence completed a survey exploring pre-Licence and Learner experiences, including the Behaviour of Young Novice Drivers Scale (BYNDS). Six months later, 351 drivers from this sample (n = 300 immediate-uptake) completed a survey exploring P1 driving. Delayed-uptake Learners reported significantly more difficulty gaining driving practice, which appeared to be associated with significantly greater engagement in unsupervised driving during the Learner period. Whilst a larger proportion of delayed-uptake novices, particularly males, reported the use of more active punishment avoidance strategies (avoiding Police, talking themselves out of a ticket) in the P1 phase, there was no significant difference in the BYNDS scores in the Learner and P1 phases according to licence-uptake category. Delayed-uptake novices report more difficulty meeting GDL requirements and place themselves at increased risk by driving unsupervised during the Learner licence phase. Additional efforts such as mentoring programs which can support the delayed-uptake Learner in meeting their GDL obligations merit further consideration to allow this novice group to gain the full benefits of the GDL program and to reduce their risk of harm in the short-term.

ECMO : the clinician’s view

Background: Extra corporeal membrane oxygenation (ECMO) is a complex rescue therapy used to provide cardiac and/or respiratory support for critically ill patients who have failed maximal conventional medical management. ECMO is based on a modified cardiopulmonary bypass (CPB) circuit, and can provide cardiopulmonary support for up-to several months. It can be used in a veno venous configuration for isolated respiratory failure, (VV-ECMO), or in a veno arterial configuration (VA-ECMO) where support is necessary for cardiac +/- respiratory failure. The ECMO circuit consists of five main components: large bore cannulae (access cannulae) for drainage of the venous system, and return cannulae to either the venous (in VV-ECMO) or arterial (in VA ECMO) system. An oxygenator, with a vast surface area of hollow filaments, allows addition of oxygen and removal of carbon dioxide; a centrifugal blood pump allows propulsion of blood through the circuit at upto 10 L/minute; a control module and a thermoregulatory unit, which allows for exact temperature control of the extra corporeal blood. Methods: The first successful use of ECMO for ARDS in adults occurred in 1972, and its use has become more commonplace over the last 30 years, supported by the improvement in design and biocompatibility of the equipment, which has reduced the morbidity associated with this modality. Whilst the use of ECMO in neonatal population has been supported by numerous studies, the evidence upon which ECMO was integrated into adult practice was substantially less robust. Results: Recent data, including the CESAR study (Conventional Ventilatory Support versus Extra corporeal membrane oxygenation for Severe Respiratory failure) has added a degree of evidence to the role of ECMO in such a patient population. The CESAR study analysed 180 patients, and confirmed that ECMO was associated with an improved rate of survival. More recently, ECMO has been utilized in numerous situations within the critical care area, including support in high-risk percutaneous interventions in cardiac catheter lab; the operating room, emergency department, as well in specialized inter-hospital retrieval services. The increased understanding of the risk:benefit profile of ECMO, along with a reduction in morbidity associated with its use will doubtless lead to a substantial rise in the utilisation of this modality. As with all extra-corporeal circuits, ECMO opposes the basic premises of the mammalian inflammation and coagulation cascade where blood comes into foreign circulation, both these cascades are activated. Anti-coagulation is readily dealt with through use of agents such as heparin, but the inflammatory excess, whilst less macroscopically obvious, continues un-abated. Platelet consumption and neutrophil activation occur rapidly, and the clinician is faced with balancing the need of anticoagulation for the circuit, against haemostasis in an acutely bleeding patient. Alterations in pharmacokinetics may result in inadequate levels of disease modifying therapeutics, such as antibiotics, hence paradoxically delaying recovery from conditions such as pneumonia. Key elements of nutrition and the innate immune system maysimilarly be affected. Summary: This presentation will discuss the basic features of ECMO to the nonspecialist, and review the clinical conundrum faced by the team treating these most complex cases.

Combustion products of bulk aluminum rods burning in high pressure oxygen

Characterization of the combustion products released during the burning of commonly used engineering metallic materials may aid in material selection and risk assessment for the design of oxygen systems. The characterization of combustion products in regards to size distribution and morphology gives useful information for systems addressing fire detection. Aluminum rods (3.2-mm diameter cylinders) were vertically mounted inside a combustion chamber and ignited in pressurized oxygen by resistively heating an aluminum/palladium igniter wire attached to the bottom of the test sample. This paper describes the experimental work conducted to establish the particle size distribution and morphology of the resultant combustion products collected after the burning was completed and subsequently analyzed. In general, the combustion products consisted of a re-solidified oxidized slag and many small hollow spheres of size ranging from about 500 nm to 1000 µm in diameter, surfaced with quenched dendritic and grain-like structures. The combustion products were characterized using optical and scanning electron microscopy.

Situational non-flammable control valves for oxygen service

Past work has clearly demonstrated that numerous commonly used metallic materials will support burning in oxygen, especially at higher pressures. An approach to rectify this significant safety problem has been successfully developed and implemented by applying the concept of Situational Non-Flammability. This approach essentially removes or breaks one leg of the conceptual fire triangle, a tool commonly used to define the three things that are required to support burning; a fuel, an ignition source and an oxidizer. Since an oxidiser is always present in an oxygen system as are ignition sources, the concept of Situational Non-Flammability essentially removes the fuel leg of the fire triangle by only utilising materials that will not burn at the maximum pressure, for example, that the control valve is to be used in. The utilisation of this approach has lead to the development of a range of oxygen components that are practically unable to burn while in service at their design pressure thus providing an unparalleled level of first safety while not compromising on the performance or endurance required in the function of these components. This paper describes the concept of Situational Non-Flammability, how it was used to theoretically evaluate designs of components for oxygen service and the outcomes of the actual development, fabrication and finally utilisation of these components in real oxygen systems in a range of flow control devices.

Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres : 13th Volume

"Seventeen peer-reviewed papers cover the latest research on the ignition and combustion of metals and non-metals, oxygen compatibility of components and systems, analysis of ignition and combustion, failure analysis and safety. It includes aerospace, military, scuba diving, and industrial oxygen applications. Topics cover: • Development of safe oxygen systems • Ignition mechanisms within oxygen systems and how to avoid them • Specific hazards that exist with the oxygen mixture breathed by divers in the scuba industry • Issues related to oxygen system level safety • Issues related to oxygen safety in breathing systems • Detailed investigations and discussions related to the burn curves that have been generated for metals that are burning in a standard test fixture This new publication is a valuable resource for professionals in the air separation industries, oxygen manufacturers, manufacturers of materials intended for oxygen service, and users of oxygen and oxygen-enriched atmospheres, including aerospace, medical, industrial gases, chemical processing, steel and metals refining, as well as to military, commercial or recreational diving."--- publisher website

Vibrational spectroscopic study of the mineral penkvilksite Na2TiSi4O11·2H2O – a mineral used for the uptake of radionuclides

We have used vibrational spectroscopy to study the formula and molecular structure of the mineral penkvilksite Na 2TiSi 4O 11·2H 2O. Penkvilksite is a mineral which may be used in the uptake of radioactive elements. Both Raman and infrared spectroscopies identify a band at 3638 cm−1 attributed to an OH-stretching vibration of hydroxyl units. The inference is that OH units are involved in the structure of penkvilksite. The formula may be well written as Na 2TiSi 4O 10(OH)2·H 2O. The mineral is characterised by a very intense Raman band at 1085 cm−1 and a broad infrared band at 1080 cm−1 assigned to SiO-stretching vibrations. Raman bands at 620, 667 and 711 cm−1 are attributed to SiO and TiO chain bonds. Water-stretching vibrations are observed as Raman bands at 3197, 3265, 3425 and 3565 cm−1. Vibrational spectroscopy enables aspects of the molecular structure of the mineral penkvilksite to be ascertained. Penkvilksite is a mineral which can incorporate actinides and lanthanides from radioactive waste.

Nanoporous Graphitic-C3N4@Carbon Metal-Free Electrocatalysts for Highly Efficient Oxygen Reduction

Based on theoretical prediction, a g-C3N4@carbon metal-free oxygen reduction reaction (ORR) electrocatalyst was designed and synthesized by uniform incorporation of g-C3N4 into a mesoporous carbon to enhance the electron transfer efficiency of g-C3N4. The resulting g-C3N4@carbon composite exhibited competitive catalytic activity (11.3 mA cm–2 kinetic-limiting current density at −0.6 V) and superior methanol tolerance compared to a commercial Pt/C catalyst. Furthermore, it demonstrated significantly higher catalytic efficiency (nearly 100% of four-electron ORR process selectivity) than a Pt/C catalyst. The proposed synthesis route is facile and low-cost, providing a feasible method for the development of highly efficient electrocatalysts.

How to achieve maximum charge carrier loading on heteroatom-substituted graphene nanoribbon edges: density functional theory study

The practical number of charge carriers loaded is crucial to the evaluation of the capacity performance of carbon-based electrodes in service, and cannot be easily addressed experimentally. In this paper, we report a density functional theory study of charge carrier adsorption onto zigzag edge-shaped graphene nanoribbons (ZGNRs), both pristine and incorporating edge substitution with boron, nitrogen or oxygen atoms. All edge substitutions are found to be energetically favorable, especially in oxidized environments. The maximal loading of protons onto the substituted ZGNR edges obeys a rule of [8-n-1], where n is the number of valence electrons of the edge-site atom constituting the adsorption site. Hence, a maximum charge loading is achieved with boron substitution. This result correlates in a transparent manner with the electronic structure characteristics of the edge atom. The boron edge atom, characterized by the most empty p band, facilitates more than the other substitutional cases the accommodation of valence electrons transferred from the ribbon, induced by adsorption of protons. This result not only further confirms the possibility of enhancing charge storage performance of carbon-based electrochemical devices through chemical functionalization but also, more importantly, provides the physical rationale for further design strategies.

Area of residence is associated with Australian women’s uptake of long-acting contraception

Objective: Several new types of contraception became available in Australia over the last twelve years (the implant in 2001, progestogen intra-uterine device (IUD) in 2003, and vaginal contraceptive ring in 2007). Most methods of contraception require access to health services. Permanent sterilisation and the insertion of an implant or IUD involve a surgical procedure. Access to health professionals providing these specialised services may be more difficult in rural areas. This paper examines uptake of permanent or long-acting reversible contraception (LARCs) among Australian women in rural areas compared to women in urban areas. Method: Participants in the Australian Longitudinal Study on Women's Health born in 1973-78 reported on their contraceptive use at three surveys: 2003, 2006 and 2009. Contraceptive methods included permanent sterilisation (tubal ligation, vasectomy), non-daily or LARC methods (implant, IUD, injection, vaginal ring), and other methods including daily, barrier or "natural" methods (oral contraceptive pills, condoms, withdrawal, safe period). Sociodemographic, reproductive history and health service use factors associated with using permanent, LARC or other methods were examined using a multivariable logistic regression analysis. Results: Of 9,081 women aged 25-30 in 2003, 3% used permanent methods and 4% used LARCs. Six years later in 2009, of 8,200 women (aged 31-36), 11% used permanent methods and 9% used LARCs. The fully adjusted parsimonious regression model showed that the likelihood of a woman using LARCs and permanent methods increased with number of children. Women whose youngest child was school-age were more likely to use LARCs (OR=1.83, 95%CI 1.43-2.33) or permanent methods (OR=4.39, 95%CI 3.54-5.46) compared to women with pre-school children. Compared to women living in major cities, women in inner regional areas were more likely to use LARCs (OR=1.26, 95%CI 1.03-1.55) or permanent methods (OR=1.43, 95%CI 1.17-1.76). Women living in outer regional and remote areas were more likely than women living in cities to use LARCs (OR=1.65, 95%CI 1.31-2.08) or permanent methods (OR=1.69, 95%CI 1.43-2.14). Women with poorer access to GPs were more likely to use permanent methods (OR=1.27, 95%CI 1.07-1.52). Conclusions: Location of residence and access to health services are important factors in women's choices about long-acting contraception in addition to the number and age of their children. There is a low level of uptake of non-daily, long-acting methods of contraception among Australian women in their mid-thirties.

The interplay between chondrocyte redifferentiation pellet size and oxygen concentration

Chondrocytes dedifferentiate during ex vivo expansion on 2-dimensional surfaces. Aggregation of the expanded cells into 3-dimensional pellets, in the presence of induction factors, facilitates their redifferentiation and restoration of the chondrogenic phenotype. Typically 1×105–5×105 chondrocytes are aggregated, resulting in “macro” pellets having diameters ranging from 1–2 mm. These macropellets are commonly used to study redifferentiation, and recently macropellets of autologous chondrocytes have been implanted directly into articular cartilage defects to facilitate their repair. However, diffusion of metabolites over the 1–2 mm pellet length-scales is inefficient, resulting in radial tissue heterogeneity. Herein we demonstrate that the aggregation of 2×105 human chondrocytes into micropellets of 166 cells each, rather than into larger single macropellets, enhances chondrogenic redifferentiation. In this study, we describe the development of a cost effective fabrication strategy to manufacture a microwell surface for the large-scale production of micropellets. The thousands of micropellets were manufactured using the microwell platform, which is an array of 360×360 µm microwells cast into polydimethylsiloxane (PDMS), that has been surface modified with an electrostatic multilayer of hyaluronic acid and chitosan to enhance micropellet formation. Such surface modification was essential to prevent chondrocyte spreading on the PDMS. Sulfated glycosaminoglycan (sGAG) production and collagen II gene expression in chondrocyte micropellets increased significantly relative to macropellet controls, and redifferentiation was enhanced in both macro and micropellets with the provision of a hypoxic atmosphere (2% O2). Once micropellet formation had been optimized, we demonstrated that micropellets could be assembled into larger cartilage tissues. Our results indicate that micropellet amalgamation efficiency is inversely related to the time cultured as discreet microtissues. In summary, we describe a micropellet production platform that represents an efficient tool for studying chondrocyte redifferentiation and demonstrate that the micropellets could be assembled into larger tissues, potentially useful in cartilage defect repair.

Determinants of uptake of whole-body skin self-examination in older men

Early detection through whole-body Skin Self-Examination (wbSSE) may decrease mortality from melanoma. Using the Health Action Process Approach (HAPA) or Health Belief Model (HBM) we aimed to assess determinants of uptake of wbSSE in 410 men 50 years of older who participated in the control group of a randomized trial. Overall, the HAPA was a significantly better predictor of wbSSE compared to the HBM (p < .001). The construct of self-efficacy in the HBM was a significant predictor of future wbSSE (p = .001), while neither perceived threat (p = .584) nor outcome expectations (p = .220) were. In contrast, self-efficacy, perceived threat, and outcome expectations predicted intention to perform SSE, which predicted behavior (p = .015). The HAPA construct volitional self-efficacy was also associated with wbSSE (p = .046). The use of the HAPA model for future SSE interventions for this population is warranted.

Cerebral cortex activation mapping upon electrical muscle stimulation by 32-channel time-domain functional near-infrared spectroscopy

The application of different EMS current thresholds on muscle activates not only the muscle but also peripheral sensory axons that send proprioceptive and pain signals to the cerebral cortex. A 32-channel time-domain fNIRS instrument was employed to map regional cortical activities under varied EMS current intensities applied on the right wrist extensor muscle. Eight healthy volunteers underwent four EMS at different current thresholds based on their individual maximal tolerated intensity (MTI), i.e., 10 % < 50 % < 100 % < over 100 % MTI. Time courses of the absolute oxygenated and deoxygenated hemoglobin concentrations primarily over the bilateral sensorimotor cortical (SMC) regions were extrapolated, and cortical activation maps were determined by general linear model using the NIRS-SPM software. The stimulation-induced wrist extension paradigm significantly increased activation of the contralateral SMC region according to the EMS intensities, while the ipsilateral SMC region showed no significant changes. This could be due in part to a nociceptive response to the higher EMS current intensities and result also from increased sensorimotor integration in these cortical regions.

Effects of hyperbaric oxygen and inducible nitric oxide synthase inhibitor treatment on femoral head osteonecrosis in a rat model

Introduction: Apoptosis is the final destiny of many cells in the body, though this process has been observed in some pathological processes. One of these pathological processes is femoral head non-traumatic osteonecrosis. Among many pro/anti-apoptotic factors, nitric oxide has recently been an area of further interest. Osteocyte apoptosis and its relation to pro-apoptotic action invite further research, and the inducible form of nitric oxide synthase (iNOS)—which produces a high concentration of nitric oxide—has been flagged. The aim of this study was to investigate the effect of hyperbaric oxygen (HBO) and inducible NOS suppressor (Aminoguanidine) in prevention of femoral head osteonecrosis in an experimental model of osteonecrosis in spontaneous hypertensive rats (SHRs). Methods: After animal ethic approval 34 SHR rats were divided into four groups. Ten rats were allocated to the control group without any treatment, and eight rats were allocated to three treatment groups namely: HBO, Aminoguanidine (AMG), and the combination of HBO and AMG treatments (HBO+AMG). The HBO group received 250 kPa of oxygen via hyperbaric chamber for 30 days started at their 5th week of life; the AMG group received 1mg/ml of AMG in drinking water from the fifth week till the 17th week of life; and the last group received a combination of these treatments. Rats were sacrificed at the end of the 17th week of life and both femurs were analysed for evidence of osteonecrosis using Micro CT scan and H&E staining. Also, osteocyte apoptosis and the presence of two different forms of NOS (inducible (iNOS) and endothelial (eNOS)) were analysed by immunostaining and apoptosis staining (Hoechst and TUNEL). Results: Bone morphology of metaphyseal and epiphyseal area of all rats were investigated and analysed. Micro CT findings revealed significantly higher mean fractional trabecular bone volume (FBV) of metaphyseal area in untreated SHRs compared with all other treatments (HBO, P<0.05, HBO+AMG, P<0.005, and AMG P<0.001). Bone surface to volume ratio also significantly increased with HBO+AMG and AMG treatments when compared with the control group (18.7 Vs 20.8, P<0.05, and 18.7 Vs 21.1, P<0.05). Epiphyseal mean FBV did not change significantly among groups. In the metaphyseal area, trabecular thickness and numbers significantly decreased with AMG treatment, while trabecular separation significantly increased with both AMG and HBO+AMG treatment. Histological ratio of no ossification and osteonecrosis was 37.5%, 43.7%, 18.7% and 6.2% of control, HBO, HBO+AMG and AMG groups respectively with only significant difference observed between HBO and AMG treatment (P<0.01). High concentration of iNOS was observed in the region of osteonecrosis while there was no evidence of eNOS activity around that region. In comparison with the control group, the ratio of osteocyte apoptosis significantly reduced in AMG treatment (P<0.005). We also observed significantly fewer apoptotic osteocytes in AMG group comparing with HBO treatment (P<0.05). Conclusion: None of our treatments prevents osteonecrosis at the histological or micro CT scan level. High concentration of iNOS in the region of osteonecrosis and significant reduction of osteocyte apoptosis with AMG treatment were supportive of iNOS modulating osteocyte apoptosis in SHRs.

Learner strategy instruction and student uptake of strategies in a Japanese as a foreign language context

The Japanese language is recognised as being more difficult than European languages, needing three times more tuition time to reach comparable levels of proficiency. Encouraging Japanese as a Foreign Language (JFL) students to become aware of, and effectively use, learner strategies is one way to assist them become more controlled, effective learners leading to enhanced language learning. This thesis investigates the development and implementation of a JFL curriculum implemented in a university course for students learning JFL. The curriculum was developed specifically to assist beginner university students with the development of learner strategies appropriate for a JFL reading context. The theoretical underpinning of the study was informed by Educational Criticism (Eisner, 1998), which aims to describe, interpret and evaluate the processes of interaction between the teacher, the learner and the curriculum and the students' learning processes in a tertiary JFL classroom. The study investigated the effect on student learning processes of a JFL reading program that incorporated explicit learner strategy instruction and identified factors that enhanced or impeded the development of learner strategy knowledge. The participants in the study were 29 students enrolled in the course, 10 of whom volunteered to undertake additional tasks, and the two teachers who implemented the curriculum. Data collection involved a number of different strategies to observe the students' participation in the classroom and learning experiences. Learning processes were investigated through TOL protocols, classroom observations, course evaluations, interviews, and learner strategy use measurement instruments (SILL, SILK and SORS) to document student uptake of learner strategies. The design of the study and its applied focus recognised my expertise as a JFL teacher, curriculum writer and researcher, an approach that aligns with the purpose of a Professional Doctorate. Four general thematics, or principles, were identified in this study: „h Explicit learner strategy instruction provides the context for students to develop awareness of learner strategies and take control of their learning; „h Collaborative learning and interaction with teachers offers students the opportunity for shared knowledge construction; „h Reflection offers teachers and students the opportunity to reflect on their own learning style and strategy knowledge, and raises awareness of other available strategies; and „h Diverse cultural and linguistic backgrounds have an impact on curriculum implementation and student uptake of learner strategies. The study¡¦s methodological contribution is that it is one of the first in Australia to use Educational Criticism (Eisner, 1998) as a research methodology. The findings contribute to theoretical knowledge in the fields of Applied Linguistics, Second Language Teaching and Learning, Second Language Acquisition and JFL Teaching and Learning by offering new knowledge on the importance of learner strategies in the beginner JFL classroom, the potential of explicit strategy instruction, the value of reflection for both teachers and students, and the important role of the teacher in the process of curriculum implementation. The general principles identified and the findings of this in-depth study of a JFL classroom can be drawn upon to inform other teaching practice situations, and invite practitioners from not just Japanese, but from other language areas and other disciplines, to examine and improve their own practices, and suggest further research questions to pursue this line of enquiry.