Cometary evolution : clues on physical properties from chondritic interplanetary dust particles

The degree of diversity or similarity detected in comets depends primarily on the lifetimes of the individual cometary nuclei at the time of analysis. It is inherent in our understanding of cometary orbital dynamics and the seminal model of comet origins that cometary evolution is the natural order of events in our Solar System. Thus, predictions of cometary behaviour in terms of bulk physical, mineralogical or chemical parameters should contain an appreciation of temporal variation(s). Previously, Rietmeijer and Mackinnon [1987] developed mineralogical bases for the chemical evolution of cometary nuclei primarily with regard to the predominantly silicate fraction of comet nuclei. We suggested that alteration of solids in cometary nuclei should be expected and that indications of likely reactants and products can be derived from judicious comparison with terrestrial diagenetic environments which include hydrocryogenic and low-temperature aqueous alterations. In a further development of this concept, Rietmeijer [1988] provides indirect evidence for the formation of sulfides and oxides in comet nuclei. Furthermore, Rietmeijer [1988] noted that timescales for hydrocryogenic and low-temperature reactions involving liquid water are probably adequate for relatively mature comets, e.g. P/comet Halley. In this paper, we will address the evolution of comet nuclei physical parameters such as solid particle grain size, porosity and density. In natural environments, chemical evolution (e.g. mineral reactions) is often accompanied by changes in physical properties. These concurrent changes are well-documented in the terrestrial geological literature, especially in studies of sediment diagenesis and we suggest that similar basic principles apply within the upper few meters of active comet nuclei. The database for prediction of comet nuclei physical parameters is, in principle, the same as used for the proposition of chemical evolution. We use detailed mineralogical studies of chondritic interplanetary dust particles (IDPS) as a guide to the likely constitution of mature comets traversing the inner Solar System. While there is, as yet, no direct proof that a specific sub-group or type of chondritic IDP is derived from a specific comet, it is clear that these particles are extraterrestrial in origin and that a certain portion of the interplanetary flux received by the Earth is cometary in origin. Two chondritic porous (CP) IDPS, sample numbers W701OA2 and W7029CI, from the Johnson Space Center Cosmic Dust Collection have been selected for this study of putative cometary physical parameters. This particular type of particle is considered a likely candidate for a cometary origin on the basis of mineralogy, bulk composition and morphology. While many IDPs have been subjected to intensive study over the past decade, we can develop a physical parameter model on only these two CP IDPs because few others have been studied in sufficient detail.

A study of post diagnosis breast cancer concerns for women living in rural and remote Queensland. Part I : Personal concerns

The findings presented in this paper are part of a research project designed to provide a preliminary indication of the support needs of postdiagnosis women with breast cancer in remote and isolated areas in Queensland. This discussion will present data that focuses on the women’s expressed personal concerns. For participants in this research a diagnosis of breast cancer involves a confrontation with their own mortality and the possibility of a reduced life span. This is a definite life crisis, creating shock and needing considerable adjustment. Along with these generic issues the participants also articulated significant issues in relation to their experience as women in a rural setting. These concerns centred around worries about how their partner and families cope during their absences for treatment, the additional burden on the family of having to cope with running the property or farm during the participant’s absence or illness, added financial strain brought about by the cost of travel for treatment, maintenance of properties during absences, and problems created by time off from properties or self-employment. These findings accord with other reports of health and welfare services for rural Australian and the generic literature on psycho-oncology studies of breast cancer.

A study of postdiagnosis breast cancer concerns for women living in rural and remote Queensland. Part II : support issues

This paper presents the recent findings from a study on the postdiagnosis support needs of women with breast cancer living in rural and remote Queensland. The findings presented in this discussion focus on support needs from the perspective of the women experiencing breast cancer as well as health service providers. The tyranny of distance imposes unique hardships, such as separation from family and friends, during a time of great vulnerability for treatment, the need to travel long distances for support and follow-up services, and extra financial burdens, which can combine to cause strains on the marital relationship and family cohesion. Positive indications are, however, that the rural communities operate on strong, informal networks of support. This network of family, friends and community can, and does, play an active role in the provision of emotional and practical support.

Caffeine ingestion and cycling power output in a low or normal muscle glycogen state

Purpose Commencing selected workouts with low muscle glycogen availability augments several markers of training adaptation compared with undertaking the same sessions with normal glycogen content. However, low glycogen availability reduces the capacity to perform high-intensity (>85% of peak aerobic power (V·O2peak)) endurance exercise. We determined whether a low dose of caffeine could partially rescue the reduction in maximal self-selected power output observed when individuals commenced high-intensity interval training with low (LOW) compared with normal (NORM) glycogen availability. Methods Twelve endurance-trained cyclists/triathletes performed four experimental trials using a double-blind Latin square design. Muscle glycogen content was manipulated via exercise–diet interventions so that two experimental trials were commenced with LOW and two with NORM muscle glycogen availability. Sixty minutes before an experimental trial, subjects ingested a capsule containing anhydrous caffeine (CAFF, 3 mg-1·kg-1 body mass) or placebo (PLBO). Instantaneous power output was measured throughout high-intensity interval training (8 × 5-min bouts at maximum self-selected intensity with 1-min recovery). Results There were significant main effects for both preexercise glycogen content and caffeine ingestion on power output. LOW reduced power output by approximately 8% compared with NORM (P < 0.01), whereas caffeine increased power output by 2.8% and 3.5% for NORM and LOW, respectively, (P < 0.01). Conclusion We conclude that caffeine enhanced power output independently of muscle glycogen concentration but could not fully restore power output to levels commensurate with that when subjects commenced exercise with normal glycogen availability. However, the reported increase in power output does provide a likely performance benefit and may provide a means to further enhance the already augmented training response observed when selected sessions are commenced with reduced muscle glycogen availability. It has long been known that endurance training induces a multitude of metabolic and morphological adaptations that improve the resistance of the trained musculature to fatigue and enhance endurance capacity and/or exercise performance (13). Accumulating evidence now suggests that many of these adaptations can be modified by nutrient availability (9–11,21). Growing evidence suggests that training with reduced muscle glycogen using a “train twice every second day” compared with a more traditional “train once daily” approach can enhance the acute training response (29) and markers representative of endurance training adaptation after short-term (3–10 wk) training interventions (8,16,30). Of note is that the superior training adaptation in these previous studies was attained despite a reduction in maximal self-selected power output (16,30). The most obvious factor underlying the reduced intensity during a second training bout is the reduction in muscle glycogen availability. However, there is also the possibility that other metabolic and/or neural factors may be responsible for the power drop-off observed when two exercise bouts are performed in close proximity. Regardless of the precise mechanism(s), there remains the intriguing possibility that the magnitude of training adaptation previously reported in the face of a reduced training intensity (Hulston et al. (16) and Yeo et al.) might be further augmented, and/or other aspects of the training stimulus better preserved, if power output was not compromised. Caffeine ingestion is a possible strategy that might “rescue” the aforementioned reduction in power output that occurs when individuals commence high-intensity interval training (HIT) with low compared with normal glycogen availability. Recent evidence suggests that, at least in endurance-based events, the maximal benefits of caffeine are seen at small to moderate (2–3 mg·kg-1 body mass (BM)) doses (for reviews, see Refs. (3,24)). Accordingly, in this study, we aimed to determine the effect of a low dose of caffeine (3 mg·kg-1 BM) on maximal self-selected power output during HIT commenced with either normal (NORM) or low (LOW) muscle glycogen availability. We hypothesized that even under conditions of low glycogen availability, caffeine would increase maximal self-selected power output and thereby partially rescue the reduction in training intensity observed when individuals commence HIT with low glycogen availability.

Review: "Breast cancer : can you prevent it?" by A. Lawson, J. Lawson. McGraw-Hill Book (1998)

While reviewing this book, I was not of the target audience. For example, there is a first chapter (presented as a case study, and integrated in an unconvincing manner into the remainder of the book) that obviously meant to soften the book for the lay person. In the third chapter, the authors provide their philosophical interpretation on the meaning of breasts for reasons that entirely escape me, and that have no relation to the book as a whole. Finally, there are potted histories of the heroics of ‘tireless’, ‘dedicated’ and ‘earnest’ epidemiologists, some of whom have nothing to do with breast cancer or the book at all. Despite this lack of focus, the authors give an honest and coherent account of the current state of breast cancer research from an epidemiological viewpoint...

Review: "Health service frameworks for small rural and remote communities: issues and options" by J. Humphreys, S. Mathews-Cowey, F. Rolley 1996

This monograph is a welcome investigation of current issues in rural health service delivery in smaller communities. The underlying assumption is that existing health service frameworks for rural and remote communities with populations of less than 230 are simply- not appropriate for their needs. With this in mind, the authors identify the strengths and weaknesses of frameworks presently utilised, and offer viable alternatives. They have made information accessible to those who wish to improve the delivery of rural health care, and have provided a catalyst for further research and dialogue on rural health issues...

Characteristics of chemotherapy practice in rural and remote area health facilities in Queensland

Objective The overall objective of this study was to document the nature of the chemotherapy nursing practice of rural and remote area nurses in Queensland. Design A questionnaire survey that elicited descriptive quantitative and qualitative data. Setting Forty-seven rural and remote area health facilities in Queensland involved in the administration of chemotherapy. Subjects Sixty-seven Queensland rural and remote area nurses involved in the administration of cytotoxic drugs. Main outcome measures: Characteristics of chemotherapy practice including context of practice, amount and type of chemotherapy administered, logistical problems, level of support from referral centres, policies and procedures, safety issues. Results The results indicate that the risks to nursing staff and the potential for poor patient outcomes are higher than in specialist chemotherapy facilities. This is largely due to the human and material resource constraints characteristic of rural practice. These include a lack of understanding on the part of metropolitan-based health departments and the specialist cancer centres that refer patients to rural areas of the constraints that may adversely influence patient outcomes. Conclusions It is essential that steps are taken to ensure that rural and remote area cancer patients have equitable access to safe and competent chemotherapy care delivered in their choice of context, and the results of this study provide guidance on ways that this can be achieved.

Why nurses are attracted to rural and remote practice

This is the second paper of a larger study that examined the factors influencing the decisions of rural and remote area nurses, formerly employed by Queensland Health, to leave or to remain in this area of nursing. The study was a cross-sectional survey that gathered data from nurses who had resigned from permanent positions in Queensland Health during the period February 1999 to May 2000. This paper reports only those factors that influenced their decision to remain in rural and remote area practice, which can be categorised into personal, professional and rural influences. The results of this study are congruent with previous national and international research findings into these issues for nurses in rural and remote areas. The paper makes recommendations to attract nurses to the rural and remote work force.

Evidence-based practice and rural nursing : A literature review

This literature review is an exploration of issues related to evidence-based practice and rural nursing. Given the contribution that nursing research can make to improved client care in rural areas, it is important that nurses’ awareness and understanding of evidence-based practice be enhanced, and that strategies for fostering the development of clinically relevant programs of nursing research be identified for rural health services. The review highlights the deficiencies in the current metropolitan-based approaches to evidence-based practice that may disadvantage rural clients and nursing practitioners, because they do not accommodate the inherent differences in rural and metropolitan healthcare cultures. It emphasises the need to seek approaches to research-based practice that arise from the specific needs of the rural setting.

A rural health education, training and research network

The purpose of the Rural Health Education, Training and Research Network is to support the education and training of rural health practitioners and research in rural health through the optimum use of appropriate information and communication technologies to link and inform all individuals and organisation involved in the teaching, planning and delivery of health care in rural and remote Queensland. The health care of people in rural areas has the potential to be enhanced, through providing the rural and remote health professionals in Queensland with the same access to educational and training opportunities as their metropolitan colleagues. This consultative, coordinated approach should be cost-effective through both increasing awareness and utilisation of existing and developing networks, and through more efficient and rational use of both the basic and sophisticated technologies which support them. Technological hardware, expertise and infrastructure are already in place in Queensland to support a Rural Health Education, Training and Research Network, but are not being used to their potential, more often due to a lack of awareness of their existence and utility than to their perceived costs. Development of the network has commenced through seeding funds provided by Queensland Health. Future expansion will ensure access by health professionals to existing networks within Queensland. This paper explores the issues and implications of a network for rural health professionals in Queensland and potentially throughout Australia, with a specific focus on the implications for rural and isolated health professional.

Business value from intelligent fields

The Smart Fields programme has been active in Shell over the last decade and has given large benefits. In order to understand the value and to underpin strategies for the future implementation programme, a study was carried out to quantify the benefits to date. This focused on actually achieved value, through increased production or lower costs. This provided an estimate of the total value achieved to date. Future benefits such as increased reserves or continued production gain were recorded separately. The paper describes the process followed in the benefits quantification. It identifies the key solutions and technologies and describes the mechanism used to understand the relation between solutions and value. Examples have been given of value from various assets around the world, in both existing fields and in green fields. Finally, the study provided the methodology for tracking of value. This helps Shell to estimate and track the benefits of the Smart Fields programme at company scale.

Ambient ionisation mass spectrometry for the characterisation of polymers and polymer additives : A review

The purpose of this review is to showcase the present capabilities of ambient sampling and ionisation technologies for the analysis of polymers and polymer additives by mass spectrometry (MS) while simultaneously highlighting their advantages and limitations in a critical fashion. To qualify as an ambient ionisation technique, the method must be able to probe the surface of solid or liquid samples while operating in an open environment, allowing a variety of sample sizes, shapes, and substrate materials to be analysed. The main sections of this review will be guided by the underlying principle governing the desorption/extraction step of the analysis; liquid extraction, laser ablation, or thermal desorption, and the major component investigated, either the polymer itself or exogenous compounds (additives and contaminants) present within or on the polymer substrate. The review will conclude by summarising some of the challenges these technologies still face and possible directions that would further enhance the utility of ambient ionisation mass spectrometry as a tool for polymer analysis. (C) 2013 Elsevier B. V. All rights reserved.

Characterising in situ activation and degradation of hindered amine light stabilisers using liquid extraction surface analysis-mass spectrometry

Changes in the molecular structure of polymer antioxidants such as hindered amine light stabilisers (HALS) is central to their efficacy in retarding polymer degradation and therefore requires careful monitoring during their in-service lifetime. The HALS, bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (TIN123) and bis-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (TIN292), were formulated in different polymer systems and then exposed to various curing and ageing treatments to simulate in-service use. Samples of these coatings were then analysed directly using liquid extraction surface analysis (LESA) coupled with a triple quadrupole mass spectrometer. Analysis of TIN123 formulated in a cross-linked polyester revealed that the polymer matrix protected TIN123 from undergoing extensive thermal degradation that would normally occur at 292 degrees C, specifically, changes at the 1- and 4-positions of the piperidine groups. The effect of thermal versus photo-oxidative degradation was also compared for TIN292 formulated in polyacrylate films by monitoring the in situ conversion of N-CH3 substituted piperidines to N-H. The analysis confirmed that UV light was required for the conversion of N-CH3 moieties to N-H - a major pathway in the antioxidant protection of polymers - whereas this conversion was not observed with thermal degradation. The use of tandem mass spectrometric techniques, including precursor-ion scanning, is shown to be highly sensitive and specific for detecting molecular-level changes in HALS compounds and, when coupled with LESA, able to monitor these changes in situ with speed and reproducibility. (C) 2013 Elsevier B. V. All rights reserved.

Desorption electrospray ionisation mass spectrometry of stabilised polyesters reveals activation of hindered amine light stabilisers

The use of hindered amine light stabilizers (HALS) to retard thermo- and photo-degradation of polymers has become increasingly common. Proposed mechanisms of polymer stabilisation involve significant changes to the HALS chemical structure; however, reports of the characterisation of these modified chemical species are limited. To better understand the fate of HALS and determine their in situ modifications, desorption electrospray ionisation mass spectrometry (DESI-MS) was employed to characterise ten commercially available HALS present in polyester-based coil coatings. TINUVIN® 770, 292, 144, 123, 152, and NOR371; HOSTAVIN® 3052, 3055, 3050, and 3058 were separately formulated with a pigmented, thermosetting polyester resin, cured on metal at 262 C and analysed directly by DESI-MS. High-level ab initio molecular orbital theory calculations were also undertaken to aid the mechanistic interpretation of the results. For HALS containing N-substituted piperidines (i.e., N-CH3, N-C(O)CH3, and N-OR) a secondary piperidine (N-H) analogue was detected in all cases. The formation of these intermediates can be explained either through hydrogen abstraction based mechanisms or direct N-OR homolysis with the former dominant under normal service temperatures (ca. 25-80 C), and the latter potentially becoming competitive under the high temperatures associated with curing (ca. 230-260 C). © 2013 Elsevier Ltd. All rights reserved.

Direct detection of additives and degradation products from polymers by liquid extraction surface analysis employing chip-based nanospray mass spectrometry

RATIONALE: Polymer-based surface coatings in outdoor applications experience accelerated degradation due to exposure to solar radiation, oxygen and atmospheric pollutants. These deleterious agents cause undesirable changes to the aesthetic and mechanical properties of the polymer, reducing its lifetime. The use of antioxidants such as hindered amine light stabilisers (HALS) retards these degradative processes; however, mechanisms for HALS action and polymer degradation are poorly understood. METHODS: Detection of the HALS TINUVINW123 (bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate) and the polymer degradation products directly from a polyester-based coil coating was achieved by liquid extraction surface analysis (LESA) coupled to a triple quadrupole QTRAPW 5500 mass spectrometer. The detection of TINUVINW123 and melamine was confirmed by the characteristic fragmentation pattern observed in LESA-MS/MS spectra that was identical to that reported for authentic samples. RESULTS: Analysis of an unstabilised coil coating by LESA-MS after exposure to 4 years of outdoor field testing revealed the presence of melamine (1,3,5-triazine-2,4,6-triamine) as a polymer degradation product at elevated levels. Changes to the physical appearance of the coil coating, including powder-like deposits on the coating's surface, were observed to coincide with melamine deposits and are indicative of the phenomenon known as polymer ' blooming'. CONCLUSIONS: For the first time, in situ detection of analytes from a thermoset polymer coating was accomplished without any sample preparation, providing advantages over traditional extraction-analysis approaches and some contemporary ambient MS methods. Detection of HALS and polymer degradation products such as melamine provides insight into the mechanisms by which degradation occurs and suggests LESA-MS is a powerful new tool for polymer analysis. Copyright (C) 2012 John Wiley & Sons, Ltd.