Force-induced activation of covalent bonds in mechanoresponsive polymeric materials

Mechanochemical transduction enables an extraordinary range of physiological processes such as the sense of touch, hearing, balance, muscle contraction, and the growth and remodelling of tissue and
bone1–6. Although biology is replete with materials systems that actively and functionally respond to mechanical stimuli, the default mechanochemical reaction of bulk polymers to large external stress is the unselective scission of covalent bonds, resulting in damage or failure7. An alternative to this degradation process is the rational molecular design of synthetic materials such that mechanical stress
favourably altersmaterial properties. A few mechanosensitive polymers with this property have been developed8–14; but their active response is mediated through non-covalent processes, which may
limit the extent to which properties can be modified and the longterm stability in structural materials. Previously, we have shown with dissolved polymer strands incorporating mechanically sensitive chemical groups—so-called mechanophores—that the directional nature of mechanical forces can selectively break and re-form covalent bonds15,16. We now demonstrate that such forceinduced covalent-bond activation can also be realized with mechanophore-linked elastomeric and glassy polymers, by using a mechanophore that changes colour as it undergoes a reversible electrocyclic ring-opening reaction under tensile stress and thus allows us to directly and locally visualize the mechanochemical reaction. We find that pronounced changes in colour and fluorescence emerge with the accumulation of plastic deformation, indicating that in these polymeric materials the transduction of mechanical force into the ring-opening reaction is an activated process. We anticipate that force activation of covalent bonds can serve as a general strategy for the development of new mechanophore building blocks that impart polymeric materials with desirable functionalities ranging from damage sensing to fully regenerative self-healing.

Pristine Early Eocene Wood Buried Deeply in Kimberlite from Northern Canada

We report exceptional preservation of fossil wood buried deeply in a kimberlite pipe that intruded northwestern Canada's Slave Province 53.3±0.6 million years ago (Ma), revealed during excavation of diamond source rock. The wood originated from forest surrounding the eruption zone and collapsed into the diatreme before resettling in volcaniclastic kimberlite to depths >300 m, where it was mummified in a sterile environment. Anatomy of the unpermineralized wood permits conclusive identification to the genus Metasequoia (Cupressaceae). The wood yields genuine cellulose and occluded amber, both of which have been characterized spectroscopically and isotopically. From cellulose d O and d H measurements, we infer that Early Eocene paleoclimates in the western Canadian subarctic were 12-17°C warmer and four times wetter than present. Canadian kimberlites offer Lagerstätte-quality preservation of wood from a region with limited alternate sources of paleobotanical information. © 2012 Wolfe et al.

Deriving lessons relating to marine spatial planning from Canada's Eastern Scotian Shelf Integrated Management Initiative

Stakeholder participation is viewed as a key element of ecosystem-based marine spatial planning (MSP). There is much debate over the effectiveness of stakeholder participation in ecosystem-based management (EBM) in general and over the form it should take. Particular challenges relating to participation in the marine environment are highlighted. A study of the Eastern Scotian Shelf Integrated Management initiative, which uses a collaborative planning model to implement EBM, is presented in order to explore these issues further. Criteria derived from a review of collaborative planning literature are employed to evaluate the effectiveness of this model, which is found to be a useful consensus-building tool. Although a strategic-level plan has been adopted, the initiative has encountered difficulties transitioning from plan development to plan implementation. These are attributable in large measure to deficiencies in the design of the collaborative model. Useful lessons relating mainly to stakeholder engagement, the role of the lead agency, and implementation strategies are advanced for those engaging in MSP processes.

Rural Support Networks in the UK and Canada: The Influence of the Patrilineal Culture of Family Farming

Rural support organisations have emerged since agricultural restructuring of the 1980s. The paper draws on research from the UK and Canada to suggest that the support in both countries is derived from a patrilineal culture that still dominates family farming. The paper begins by outlining a conceptual basis for arguing that such a culture can be understood as comprising of male and female relational gender identities capable of explaining farm relationships, farm survival and adjustment strategies and community engagement. These components, it is argued, are facets of the patrilineal farming culture which must be understood if its impacts on all its members are to be appropriately comprehended and supported.

The paper has two key aims, therefore. Firstly it suggests that a more nuanced understanding of farming „culture? which is persistently patrilineal in nature is now required which is capable of addressing the realities of farming individuals?
lives as they perceive them. The conceptualisation of such a culture is informed
by drawing on insights from gender theory, agricultural geography and rural studies. This conceptual discussion provides the context for the paper?s second aim which is to demonstrate how rural support in both the UK and Canada is derived „from? and is influenced by such a patrilineal culture . Findings are
presented identifying five key themes from this conceptualization which influence the support of such organisations. Thus, it is suggested, that the nature of rural support can be better understood and the appropriateness of the support interrogated when such conceptualization is taken on board.

The failure of generalized gradient approximations (GGAs) and meta-GGAs for the two-center three-electron bonds in He-2(+), (H2O)(2)(+), and (NH3)(2)(+)

The radical cations He-2(+) (H2O)(2)(+), and (NH3)(2)(+) with two-center three-electron A-A bonds are investigated at the configuration interaction (CI), accurate Kohn-Sham (KS), generalized gradient approximation (GGA), and meta-GGA levels. Assessment of seven different GGA and six meta-GGA methods shows that the A(2)(+) systems remain a difficult case for density functional theory (DFT). All methods tested consistently overestimate the stability of A(2)(+): the corresponding D-e errors decrease for more diffuse valence densities in the series He-2(+) > (H2O)(2)(+) > (NH3)(2)(+). Upon comparison to the energy terms of the accurate Kohn-Sham solutions, the approximate exchange functionals are found to be responsible for the errors of GGA-type methods, which characteristically overestimate the exchange in A(2)(+). These so-called exchange functionals implicitly use localized holes. Such localized holes do occur if there is left-right correlation, i.e., the exchange functionals then also describe nondynamical correlation. However, in the hemibonded A(2)(+) systems the typical molecular (left-right, nondynamical) correlation of the two-electron pair bond is absent. The nondynamical correlation built into the exchange functionals is then spurious and yields too low energies.

Ethics in neuroscience graduate training programs:Views and models from Canada

Consideration of the ethical, social, and policy implications of research has become increasingly important to scientists and scholars whose work focuses on brain and mind, but limited empirical data exist on the education in ethics available to them. We examined the current landscape of ethics training in neuroscience programs, beginning with the Canadian context specifically, to elucidate the perceived needs of mentors and trainees and offer recommendations for resource development to meet those needs. We surveyed neuroscientists at all training levels and interviewed directors of neuroscience programs and training grants. A total of 88% of survey respondents reported general interest in ethics, and 96% indicated a desire for more ethics content as it applies to brain research and clinical translation. Expert interviews revealed formal ethics education in over half of programs and in 90% of grants-based programs. Lack of time, resources, and expertise, however, are major barriers to expanding ethics content in neuroscience education. We conclude with an initial set of recommendations to address these barriers which includes the development of flexible, tailored ethics education tools, increased financial support for ethics training, and strategies for fostering collaboration between ethics experts, neuroscience program directors, and funding agencies. © 2010 the Authors. Journal Compilation © 2010 International Mind, Brain, and Education Society and Blackwell Publishing, Inc.

Family caregivers' ideal expectations of Canada's Compassionate Care Benefit

We present the findings of 57 interviews conducted in 2007-2008 with Canadians who have cared for a dying family member to examine their ideal expectations of the Compassionate Care Benefit (CCB) - a social programme providing job security and income support for workers caring for a dying person. Our aims are to (1) appreciate how intended users and other family caregivers view the programme's very nature; (2) identify programme challenges and improvements that emerge from considering family caregivers' ideal expectations; and (3) contribute to a larger evaluative study designed to make policy-relevant recommendations for CCB improvement. Review of transcripts across three respondent groups reveals four categories of ideal expectations: (1) eligibility, (2) informational, (3) timing and (4) financial. Ideal expectations were typically derived from respondents' experiences of care-giving, their knowledge of the programme and, for some, of applying for and/or receiving the CCB. Findings reveal that there are gaps between respondents' ideal expectations and their experienced realities. Such gaps may lead to disappointment being experienced by those who believe they should be eligible for the programme but are not, or should be entitled to receive some form of support that is not presently available. This analysis plays an important role in identifying potential changes for the CCB that may better support family caregivers, in that the ideal expectations serve as a starting point for articulating desirable programme amendments. This analysis also has wider relevance. For jurisdictions looking to create new social programmes to support caregivers based upon labour policy strategies and legislation, this analysis identifies considerations that should be made at the outset of development. For jurisdictions that already have employment-based caregiver support programmes, this analysis demonstrates that programme challenges may not always be met through legislative changes alone but also through measures such as increasing awareness. © 2011 Blackwell Publishing Ltd.

Canada's Compassionate Care Benefit:Is it an adequate public health response to addressing the issue of caregiver burden in end-of-life care?

Background: An increasingly significant public health issue in Canada, and elsewhere throughout the developed world, pertains to the provision of adequate palliative/end-of-life (P/EOL) care. Informal caregivers who take on the responsibility of providing P/EOL care often experience negative physical, mental, emotional, social and economic consequences. In this article, we specifically examine how Canada's Compassionate Care Benefit (CCB) - a contributory benefits social program aimed at informal P/EOL caregivers - operates as a public health response in sustaining informal caregivers providing P/EOL care, and whether or not it adequately addresses known aspects of caregiver burden that are addressed within the population health promotion (PHP) model. Methods. As part of a national evaluation of Canada's Compassionate Care Benefit, 57 telephone interviews were conducted with Canadian informal P/EOL caregivers in 5 different provinces, pertaining to the strengths and weaknesses of the CCB and the general caregiving experience. Interview data was coded with Nvivo software and emerging themes were identified by the research team, with such findings published elsewhere. The purpose of the present analysis was identified after comparing the findings to the literature specific to caregiver burden and public health, after which data was analyzed using the PHP model as a guiding framework. Results: Informal caregivers spoke to several of the determinants of health outlined in the PHP model that are implicated in their burden experience: gender, income and social status, working conditions, health and social services, social support network, and personal health practises and coping strategies. They recognized the need for improving the CCB to better address these determinants. Conclusions: This study, from the perspective of family caregivers, demonstrates that the CCB is not living up to its full potential in sustaining informal P/EOL caregivers. Effort is required to transform the CCB so that it may fulfill the potential it holds for serving as one public health response to caregiver burden that forms part of a healthy public policy that addresses the determinants of this burden. © 2011 Williams et al; licensee BioMed Central Ltd.

The influence of culture on home-based family caregiving at end-of-life: A case study of Dutch reformed family care givers in Ontario, Canada

Families are facing increased pressure to provide care to their terminally-ill or dying kin in the home. It is known that balancing care with other personal and social roles can adversely affect family caregivers' (FCGs) health, yet access to supportive services which can mitigate burden is often inadequate. Cultural factors are known to shape the experience of caregiving; however, most research to date tends to neglect the experiences of FCGs from different cultural groups. This understanding is necessary to ensure that supportive services are both meaningful and culturally-appropriate. Using qualitative methods, we undertook longitudinal research with a sample of Dutch Reformed FCGs (n = 5) to understand their experiences of caregiving and bereavement. The results of the study are suggestive of a cultural specificity with respect to caregiving that impacts both responsibilities and reactions to care. Three themes were salient to this group as a cultural entity: cultural attitudes towards care, religious beliefs and coping, and c. ulturally-informed care-seeking behaviours. These three themes were seen to be a function of their religious and ethnic identities and were reinforced by ties to the communities in which they resided. Cultural identity provided a framework through which to understand and make sense of the experience, while group membership provided access to networks of informal support. This research contributes to the geographical literature on care/caregiving by providing insight into the social, cultural and religious context of informal family caregiving with a population who live in close geographic proximity. On a practical level, this case study indicates the importance of considering how these factors may operate in other settings in order to implement timely and appropriate interventions to better support FCGs who are caring for their terminally-ill loved-ones at home.

Effect of a clinical pathway to reduce hospitalizations in nursing home residents with pneumonia:A randomized controlled trial

Context: Nursing home residents with pneumonia are frequently hospitalized. Such transfers may be associated with multiple hazards of hospitalization as well as economic costs. Objective: To assess whether using a clinical pathway for on-site treatment of pneumonia and other lower respiratory tract infections in nursing homes could reduce hospital admissions, related complications, and costs. Design, Setting, and Participants: A cluster randomized controlled trial of 680 residents aged 65 years or older in 22 nursing homes in Hamilton, Ontario, Canada. Nursing homes began enrollment between January 2, 2001, and April 18, 2002, with the last resident follow-up occurring July 4, 2005. Residents were eligible if they met a standardized definition of lower respiratory tract infection. Interventions: Treatment in nursing homes according to a clinical pathway, which included use of oral antimicrobials, portable chest radiographs, oxygen saturation monitoring, rehydration, and close monitoring by a research nurse, or usual care. Main Outcome Measures: Hospital admissions, length of hospital stay, mortality, health-related quality of life, functional status, and cost. Results: Thirty-four (10%) of 327 residents in the clinical pathway group were hospitalized compared with 76 (22%) of 353 residents in the usual care group. Adjusting for clustering of residents in nursing homes, the weighted mean reduction in hospitalizations was 12% (95% confidence interval [CI], 5%-18%; P=.001). The mean number of hospital days per resident was 0.79 in the clinical pathway group vs 1.74 in the usual care group, with a weighted mean difference of 0.95 days per resident (95% CI, 0.34-1.55 days; P=.004). The mortality rate was 8% (24 deaths) in the clinical pathway group vs 9% (32 deaths) in the usual care group, with a weighted mean difference of 2.9% (95% CI, -2.0% to 7.9%; P=.23). There were no significant differences between the groups in health-related quality of life or functional status. The clinical pathway resulted in an overall cost savings of US $1016 per resident (95% CI, $207-$1824) treated. Conclusion: Treating residents of nursing homes with pneumonia and other lower respiratory tract infections with a clinical pathway can result in comparable clinical outcomes, while reducing hospitalizations and health care costs. ©2006 American Medical Association. All rights reserved.

Educating families about end-of-life care in advanced dementia:Acceptability of a Canadian family booklet to nurses from Canada, France, and Japan

Background: The families of people with late-stage dementia need to be informed about the course of the dementia and the comfort/ palliative care option. A booklet was written for that purpose and can be provided to family members by physicians and nurses. Methods: The acceptability of the booklet for nurses was tested in Canada (French and English version), France (French Canadian version) and Japan (translated and adapted version). Results: Overall, 188 nurses completed a survey questionnaire. The booklet was accepted best in Canada and less so in France and Japan. Despite regional variation, the majority of the nurses perceived the booklet as useful for families. The French and Japanese nurses also reported a greater need for palliative care education in advanced dementia. Conclusion: The booklet may help nurses educate families about end-of-life issues in dementia palliative care, but local adaptation of the booklet content and physician engagement are necessary.