Multiple quantum filtered nuclear magnetic resonance of 23Na+ in uniformly stretched and compressed hydrogels.

Stretching or compressing hydrogels creates anisotropic environments that lead to motionally averaged alignment of embedded guest quadrupolar nuclear spins such as 23Na+. These distorted hydrogels can elicit a residual quadrupolar coupling that gives an oscillation in the trajectories of single quantum coherences (SQCs) as a function of the evolution time during a spin-echo experiment. We present solutions to equations of motion derived with a Liouvillian superoperator approach, which encompass the coherent quadrupolar interaction in conjunction with relaxation, to give a full analytical description of the evolution trajectories of rank-1 (T^1±1), rank-2 (T^2±1), and rank-3 (T^3±1) SQCs. We performed simultaneous numerical fitting of the experimental 23Na nuclear magnetic resonance (NMR) spectra and rank-2 (T^2±1) and rank-3 (T^3±1) SQC evolution trajectories measured in double and triple quantum filtered experiments, respectively. We estimated values of the quadrupolar coupling constant CQ, rotational correlation time τC, and 3 × 3 Saupe order matrix. We performed simultaneous fitting of the analytical expressions to the experimental data to estimate values of the quadrupolar coupling frequency ωQ/2π, residual quadrupolar coupling ωQ/2π, and corresponding spherical order parameter S0*, which showed a linear dependence on the extent of uniform hydrogel stretching and compression. The analytical expressions were completely concordant with the numerical approach. The insights gained here can be extended to more complicated (biological) systems such as 23Na+ bound to proteins or located inside and outside living cells in high-field NMR experiments and, by extension, to the anisotropic environments found in vivo with 23Na magnetic resonance imaging.

Validation of the Saint Louis University Quality of Life Questionnaire in Older Adults with Alzheimer's Disease.

BACKGROUND/OBJECTIVES: Alzheimer's disease (AD) is the most common cause of dementia and negatively impacts individuals' quality of life (QOL). One essential component of disease management in older adults with AD is the maintenance and improvement of QOL. The QOL-AD is a tool that can be administered to evaluate QOL in AD patients, but it can take too long to administer in a patient visit. The purpose of this study was to investigate the validity of a more brief, 6-item QOL questionnaire, LIFEAD, comparing it to the QOL-AD in older adults with mild to moderate cognitive dysfunction. DESIGN: Prospective validation study. SETTING: Participants were patients presenting to internal medicine and geriatrics outpatient clinics and a nursing home. PARTICIPANTS: 285 adults 65 and older with mild to moderate cognitive impairment. MEASUREMENTS: QOL was assessed using LIFEAD and the QOL-AD. Demographic data were collected and level of depression was determined through a demographic questionnaire and the PHQ-8, respectively. RESULTS: QOL-AD mean item scores ranged from 2.27-3.32 with an average scale total of 36.28 ± 6.48. LIFEAD mean item scores ranged from 2.26-2.51 with an average scale total of 14.28 ± 2.87. A majority (68%) of patients rated all items on LIFEAD as either average or good. The correlation between LIFEAD and the QOL-AD was 0.71 (p<0.001). Both LIFEAD and the QOL-AD showed strong internal consistency with a Cronbach's alpha of 0.82 and 0.87, respectively. CONCLUSION: This study validated LIFEAD and exhibited LIFEAD can assess QOL in older adults with mild to moderate cognitive dysfunction in the clinic or nursing home. LIFEAD is a short, practical questionnaire and is easily administered in approximately 1 minute. Further research on LIFEAD could be done with larger samples, in different clinical populations, and including persons of other ethnic backgrounds.

Choices are inevitable: A qualitative exploration of the lifecosts of systemic lupus erythematosus.

OBJECTIVES: Individuals with systemic lupus erythematosus experience considerable economic challenges. The aim of this research is to qualitatively investigate experiences of the lifecosts (direct and indirect economic costs and beyond) to those with systemic lupus erythematosus in Canada. METHODS: Using a biopsychosocial conceptual framework and integrated knowledge translation approach, qualitative semi-structured interviews were conducted with 3 physicians, 5 representatives from systemic lupus erythematosus advocacy groups, and 29 adult systemic lupus erythematosus patients. Themes emerged deductively and inductively, and the theme code set was used to code all transcripts. RESULTS: Three dominant themes emerged: (1) impacts of systemic lupus erythematosus on quality of life, relationships, and health; (2) costs linked to healthcare; and (3) impacts of living with systemic lupus erythematosus on employment/economic standing. DISCUSSION: Whereas previous work has focused almost exclusively on the direct, individual costs of systemic lupus erythematosus, the biopsychosocial approach taken here emphasizes not only the individual and intermediate factors (such as the workplace and family), but also the system-level factors (i.e. system-level policies) that influence quality of life, healthcare, and employment/economic experiences of those with systemic lupus erythematosus. Results indicate a need to target interventions beyond the individual and their immediate context, and recognize that lifecosts are shaped significantly by systems-level action.

Nuclear singlet relaxation by scalar relaxation of the second kind in the slow-fluctuation regime.

The singlet state of nuclear spin-1/2 pairs is protected against many common relaxation mechanisms. Singlet order, which is defined as the population difference between the nuclear singlet and triplet states, usually decays more slowly than the nuclear magnetization. Nevertheless, some decay mechanisms for nuclear singlet order persist. One such mechanism is called scalar relaxation of the second kind (SR2K) and involves the relaxation of additional nuclei ("third spins") which have scalar couplings to the spin-1/2 pair. This mechanism requires a difference between the couplings of at least one third spin with the two members of the spin-1/2 pair, and depends on the longitudinal relaxation time of the third spin. The SR2K mechanism of nuclear singlet relaxation has previously been examined in the case where the relaxation rate of the additional spins is on the time scale of the nuclear Larmor frequency. In this paper, we consider a different regime, in which the longitudinal relaxation of the third spins is on a similar time scale to the J-coupling between the members of the spin pair. This regime is often encountered when the spin-1/2 pair has scalar couplings to nearby deuterium nuclei. We show that the SR2K mechanism may be suppressed in this regime by applying a radiofrequency field which is resonant either with the members of the spin pair, or with the third spins. These phenomena are analyzed theoretically and by numerical simulations, and demonstrated experimentally on a diester of [13C2, 2H2]-labeled fumarate in solution.

Searching for rigour in the reporting of mixed methods population health research: a methodological review.

The environments in which population health interventions occur shape both their implementation and outcomes. Hence, when evaluating these interventions, we must explore both intervention content and context. Mixed methods (integrating quantitative and qualitative methods) provide this opportunity. However, although criteria exist for establishing rigour in quantitative and qualitative research, there is poor consensus regarding rigour in mixed methods. Using the empirical example of school-based obesity interventions, this methodological review examined how mixed methods have been used and reported, and how rigour has been addressed. Twenty-three peer-reviewed mixed methods studies were identified through a systematic search of five databases and appraised using the guidelines for Good Reporting of a Mixed Methods Study. In general, more detailed description of data collection and analysis, integration, inferences and justifying the use of mixed methods is needed. Additionally, improved reporting of methodological rigour is required. This review calls for increased discussion of practical techniques for establishing rigour in mixed methods research, beyond those for quantitative and qualitative criteria individually. A guide for reporting mixed methods research in population health should be developed to improve the reporting quality of mixed methods studies. Through improved reporting, mixed methods can provide strong evidence to inform policy and practice.

Nonlinear damping and quasi-linear modelling.

The mechanism of energy dissipation in mechanical systems is often nonlinear. Even though there may be other forms of nonlinearity in the dynamics, nonlinear damping is the dominant source of nonlinearity in a number of practical systems. The analysis of such systems is simplified by the fact that they show no jump or bifurcation behaviour, and indeed can often be well represented by an equivalent linear system, whose damping parameters depend on the form and amplitude of the excitation, in a 'quasi-linear' model. The diverse sources of nonlinear damping are first reviewed in this paper, before some example systems are analysed, initially for sinusoidal and then for random excitation. For simplicity, it is assumed that the system is stable and that the nonlinear damping force depends on the nth power of the velocity. For sinusoidal excitation, it is shown that the response is often also almost sinusoidal, and methods for calculating the amplitude are described based on the harmonic balance method, which is closely related to the describing function method used in control engineering. For random excitation, several methods of analysis are shown to be equivalent. In general, iterative methods need to be used to calculate the equivalent linear damper, since its value depends on the system's response, which itself depends on the value of the equivalent linear damper. The power dissipation of the equivalent linear damper, for both sinusoidal and random cases, matches that dissipated by the nonlinear damper, providing both a firm theoretical basis for this modelling approach and clear physical insight. Finally, practical examples of nonlinear damping are discussed: in microspeakers, vibration isolation, energy harvesting and the mechanical response of the cochlea.

Engaging First Nation and Inuit communities in asthma management and control: assessing cultural appropriateness of educational resources.

INTRODUCTION: Asthma is a growing concern in First Nations and Inuit communities. As with many health indicators and outcomes, Aboriginal peoples living in remote areas experience greater disparities in respiratory health compared with non-Aboriginal Canadians. Therefore, it is critically important to take into account their unique needs when developing asthma educational materials and resources. The purpose of this study is to assess the cultural relevance of existing asthma education materials for First Nations and Inuit peoples. Five First Nations and Inuit communities from across Canada participated in the project. METHODS: A combination of quantitative evaluations (eg surveys) and qualitative approaches (eg open discussion, live chats) were used to assess printed and web-based asthma education materials. Participants represented First Nations and Inuit communities from across Canada and were selected on the basis of age and role: 6 to 12 years old (children), 12 and over (youth), parents and grandparents, community leaders and teachers, and community advisory group members. RESULTS: In general, the results showed that although participants of all age categories liked the selection of asthma educational materials and resources, they identified pictures and images related to First Nations and Inuit people living and coping with asthma as ways of improving cultural relevance. This reinforces findings that tailoring materials to include Aboriginal languages, ceremonies and traditions would enhance their uptake. Our findings also demonstrate that visually based content in both printed and virtual form were the preferred style of learning of all participants, except young children who preferred to learn through play and interactive activities. CONCLUSIONS: Asthma is a growing concern in First Nations and Inuit communities. Given this concern, it is essential to understand cultural needs and preferences when developing asthma education materials and resources. The findings from this research emphasize the need to adapt existing asthma educational materials to better suit First Nations and Inuit cultures and the importance of directly engaging community members in the process.

Frequency-dependent properties of the tectorial membrane facilitate energy transmission and amplification in the cochlea.

The remarkable sensitivity, frequency selectivity, and dynamic range of the mammalian cochlea relies on longitudinal transmission of minuscule amounts of energy as passive, pressure-driven, basilar membrane (BM) traveling waves. These waves are actively amplified at frequency-specific locations by a mechanism that involves interaction between the BM and another extracellular matrix, the tectorial membrane (TM). From mechanical measurements of isolated segments of the TM, we made the important new (to our knowledge) discovery that the stiffness of the TM is reduced when it is mechanically stimulated at physiologically relevant magnitudes and at frequencies below their frequency place in the cochlea. The reduction in stiffness functionally uncouples the TM from the organ of Corti, thereby minimizing energy losses during passive traveling-wave propagation. Stiffening and decreased viscosity of the TM at high stimulus frequencies can potentially facilitate active amplification, especially in the high-frequency, basal turn, where energy loss due to internal friction within the TM is less than in the apex. This prediction is confirmed by neural recordings from several frequency regions of the cochlea.

Multifunctional design of inertially-actuated velocity feedback controllers.

The vibration of a structure can be controlled using either a passive tuned mass damper or using an active vibration control system. In this paper, the design of a multifunctional system is discussed, which uses an inertial actuator as both a tuned mass damper and as an element in a velocity feedback control loop. The natural frequency of the actuator would normally need to be well below that of the structure under control to give a stable velocity feedback controller, whereas it needs to be close to the natural frequency of a dominant structural resonance to act as an effective tuned mass damper. A compensator is used in the feedback controller here to allow stable feedback operation even when the actuator natural frequency is close to that of a structural mode. A practical example of such a compensator is described for a small inertial actuator, which is then used to actively control the vibrations both on a panel and on a beam. The influence of the actuator as a passive tuned mass damper can be clearly seen before the feedback loop is closed, and broadband damping is then additionally achieved by closing the velocity feedback loop.

The place of health and the health of place: dengue fever and urban governance in Putrajaya, Malaysia.

This case study investigates the connections among urban planning, governance and dengue fever in an emerging market context in the Global South. Key informant interviews were conducted with leading figures in public health, urban planning and governance in the planned city of Putrajaya, Malaysia. Drawing on theories of urban political ecology and ecosocial epidemiology, the qualitative study found the health of place - expressed as dengue-bearing mosquitoes and dengue fever in human bodies in the urban environment - was influenced by the place of health in a hierarchy of urban priorities.

Comparing school environments with and without legislation for the prevention and management of anaphylaxis.

BACKGROUND: School personnel in contact with students with life-threatening allergies often lack necessary supports, creating a potentially dangerous situation. Sabrina's Law, the first legislation in the world designed to protect such children, requires all Ontario public schools to have a plan to protect children at risk. Although it has captured international attention, the differences a legislative approach makes have not been identified. Our study compared the approaches to anaphylaxis prevention and management in schools with and without legislation. METHODS: Legislated (Ontario) and nonlegislated (Alberta, British Columbia, Newfoundland and Labrador, and Quebec) environments were compared. School board anaphylaxis policies were assessed for consistency with Canadian anaphylaxis guidelines. Parents of at-risk children and school personnel were surveyed to determine their perspectives on school practices. School personnel's EpiPen5 technique was assessed. RESULTS: Consistency of school board policies with anaphylaxis guidelines was significantly better in a legislated environment (P=0.009). Parents in a legislated environment reported more comprehensive anaphylaxis emergency forms (P<0.001), while school personnel in nonlegislated environments reported more comprehensive forms (P=0.004). Despite school personnel in both environments receiving EpiPen5 training (>80%), suboptimal technique was commonly observed. However, school personnel in the legislated environment had better technique (P<0.001). CONCLUSION: Our results suggest that school boards in legislated environments have made greater efforts to support students at risk for anaphylaxis compared to nonlegislated environments. However, significant gaps exist in both environments, especially with respect to EpiPen5 administration, content, and distribution of anaphylaxis emergency forms, and awareness of school procedures by school personnel and parents.

Demographic predictors of peanut, tree nut, fish, shellfish, and sesame allergy in Canada.

Background. Studies suggest that the rising prevalence of food allergy during recent decades may have stabilized. Although genetics undoubtedly contribute to the emergence of food allergy, it is likely that other factors play a crucial role in mediating such short-term changes. Objective. To identify potential demographic predictors of food allergies. Methods. We performed a cross-Canada, random telephone survey. Criteria for food allergy were self-report of convincing symptoms and/or physician diagnosis of allergy. Multivariate logistic regressions were used to assess potential determinants. Results. Of 10,596 households surveyed in 2008/2009, 3666 responded, representing 9667 individuals. Peanut, tree nut, and sesame allergy were more common in children (odds ratio (OR) 2.24 (95% CI, 1.40, 3.59), 1.73 (95% CI, 1.11, 2.68), and 5.63 (95% CI, 1.39, 22.87), resp.) while fish and shellfish allergy were less common in children (OR 0.17 (95% CI, 0.04, 0.72) and 0.29 (95% CI, 0.14, 0.61)). Tree nut and shellfish allergy were less common in males (OR 0.55 (95% CI, 0.36, 0.83) and 0.63 (95% CI, 0.43, 0.91)). Shellfish allergy was more common in urban settings (OR 1.55 (95% CI, 1.04, 2.31)). There was a trend for most food allergies to be more prevalent in the more educated (tree nut OR 1.90 (95% CI, 1.18, 3.04)) and less prevalent in immigrants (shellfish OR 0.49 (95% CI, 0.26, 0.95)), but wide CIs preclude definitive conclusions for most foods. Conclusions. Our results reveal that in addition to age and sex, place of residence, socioeconomic status, and birth place may influence the development of food allergy.

You cannot prevent a disease; you only treat diseases when they occur: knowledge, attitudes and practices to water-health in a rural Kenyan community.

OBJECTIVE: Almost 1 billion individuals lack access to improved water supplies, with 2.6 billion lacking adequate sanitation. This leads to the propagation of multiple waterborne diseases. The objective of this study was to explore local knowledge, attitudes and practices to understand the mechanisms and pre-conditions for sustainable uptake and use of these facilities. METHODS: Data collection took place in a rural Kenyan community in September 2009. A qualitative approach was taken, with 4 focus groups and 25 in-depth interviews conducted. Participant characteristics varied by age, gender, education, marital status, employment and community standing. RESULTS: Few participants reported current access to improved water and sanitation facilities. Though they expressed desire for latrines and water sources, barriers including lack of funds and social capital, decrease the ability for installation. Participants understood that there was a link between the quality of water and their health, however, perceived benefits of current contaminated sources outweigh the potential health impacts and proliferate their continued use. CONCLUSION(S): While water-health links are understood to varying degrees within the community, contextual (physical environment), compositional (individual) and collective (community) factors interact to influence health. Community challenges, such as lack of unity, lack of education and lack control were identified as the main barriers to initiating change, despite a desire for increased access to safe water and sanitation.

Prescribing of psychotropic medication to the intellectually disabled by community paediatricians - a survey.

BACKGROUND: Children with intellectual disability are often managed by community paediatricians and have a high prevalence of mental disorder. We do not know whether community paediatricians feel adequately trained to treat this group although we know that paediatricians contribute significantly to psychotropic prescribing for children. METHODS: Psychotropic medication prescribing by community paediatricians to the intellectually disabled in the north-west and northern regions, community paediatricians' perceived training needs in this area and the availability of specialized psychiatric services were surveyed. Postal questionnaires were sent to all members of the British Association of Community Child Health in the north and north western regions (n= 155), between summer 2004 and autumn 2005. RESULTS: A total of 70.1% (n= 110) of questionnaires were returned of which 66 were completed. The most common reason for non-completion was that the respondent did not look after the intellectually disabled. A total of 54.5% of respondents did not have access to specialist psychiatry services for children and adolescents with an intellectual disability. Community paediatricians were most likely to prescribe for sleep disorders and attention deficit hyperactivity disorder (ADHD). There was a significant relationship between perceived adequacy of training and paediatrics prescribing for ADHD, but there was no such relationship for sleep disorders. The vast majority of community paediatricians did not feel adequately trained to prescribe for challenging behaviour or depression, although a small minority did prescribe. CONCLUSIONS: Community paediatricians play a substantial role in prescribing psychotropic medications for this group. A substantial minority of community paediatricians do not feel that they have enough training to prescribe for ADHD and sleep disorders, and perceived competency is more likely to inform prescribing for ADHD than for sleep disorders. This may have implications for training. Although these children pose complex difficulties, access to specialist mental health services for children and adolescents with intellectual disability remains patchy, especially in the north-west, and further development of these services is needed.

Levitation-free vibrated droplets: resonant oscillations of liquid marbles.

A spherical conducting droplet in an alternating electric field is known to undergo shape oscillations. When the droplet is supported by a substrate, the shape is no longer a complete sphere, but shape resonances are still observed. To obtain a completely spherical droplet, some kind of levitation is needed, unless the droplet is in microgravity, and this has previously been provided by gas films or magnetic or other external forces. In this work, we report observations of shape oscillations of a hydrophobic-powder-coated droplet of water. A droplet of water rolled on a hydrophobic powder self-coats such that the water becomes encapsulated as a liquid marble. When the powder is a spherical hydrophobic grain with a contact angle greater than 90 degrees , it adheres to the solid-water interface with more than half of its diameter projecting from the liquid, thus ensuring the encapsulated water does not come into contact with any substrate. These liquid marbles are highly mobile and can be regarded as completely nonwetting droplets possessing contact angles of 180 degrees . In this work, we show that they also provide a new mechanism equivalent to levitating droplets and provide droplets with small contact areas and completely mobile contact lines for studies of shape oscillations. Liquid marbles were created using hydrophobic lycopodium and droplets of water containing potassium chloride and were excited into motion using an electrowetting-on-dielectric configuration with applied frequency swept from 1 to 250 Hz. Both an up-and-down motion and an oscillation involving multiple nodes were observed and recorded using a high-speed camera. The resonant oscillation modes of small liquid marbles were fitted to the theory for vibrations of a free spherical volume of fluid. This work demonstrates the principle that oscillation modes of completely nonwetting droplets can be studied using a simple powder coating approach without the need for an active mechanism for levitation.

Electrowetting of nonwetting liquids and liquid marbles.

Transport of a water droplet on a solid surface can be achieved by differentially modifying the contact angles at either side of the droplet using capacitive charging of the solid-liquid interface (i.e., electrowetting-on-dielectric) to create a driving force. Improved droplet mobility can be achieved by modifying the surface topography to enhance the effects of a hydrophobic surface chemistry and so achieve an almost complete roll-up into a superhydrophobic droplet where the contact angle is greater than 150 degrees . When electrowetting is attempted on such a surface, an electrocapillary pressure arises which causes water penetration into the surface features and an irreversible conversion to a state in which the droplet loses its mobility. Irreversibility occurs because the surface tension of the liquid does not allow the liquid to retract from these fixed surface features on removal of the actuating voltage. In this work, we show that this irreversibility can be overcome by attaching the solid surface features to the liquid surface to create a liquid marble. The solid topographic surface features then become a conformable "skin" on the water droplet both enabling it to become highly mobile and providing a reversible liquid marble-on-solid system for electrowetting. In our system, hydrophobic silica particles and hydrophobic grains of lycopodium are used as the skin. In the region corresponding to the solid-marble contact area, the liquid marble can be viewed as a liquid droplet resting on the attached solid grains (or particles) in a manner similar to a superhydrophobic droplet resting upon posts fixed on a solid substrate. When a marble is placed on a flat solid surface and electrowetting performed it spreads but with the water remaining effectively suspended on the grains as it would if the system were a droplet of water on a surface consisting of solid posts. When the electrowetting voltage is removed, the surface tension of the water droplet causes it to ball up from the surface but carrying with it the conformable skin. A theoretical basis for this electrowetting of a liquid marble is developed using a surface free energy approach.

An exploratory spatial analysis of pneumonia and influenza hospitalizations in Ontario by age and gender.

Pneumonia and influenza represent a significant public health burden in Canada and abroad. Knowledge of how this burden varies geographically provides clues to understanding the determinants of these illnesses, and insight into the effective management of health-care resources. We conducted a retrospective, population-based, ecological-level study to assess age- and gender-specific spatial patterns of pneumonia and influenza hospitalizations in the province of Ontario, Canada from 1992 to 2001. Results revealed marked variability in hospitalization rates by age, as well as clear and statistically significant patterns of high rates in northern rural counties and low rates in southern urban counties. A moderate yet significant level of positive spatial autocorrelation (Moran's I=0.21, P<0.05) was found in the global data, with significant, age-specific clusters of high values or 'hot spots' identified in several northern counties. Findings illustrate the need for geographically focused prevention strategies, and resource and service allocation policies informed by regional and population-specific demands.

The political ecology of health: perceptions of environment, economy, health and well-being among 'Namgis First Nation.

Informed by Mayer's (Progr. Hum. Geogr 20 (1996) 441) political ecology of disease framework, this paper investigates First Nation's perceptions of the links between environment, economy and health and well-being. A case study of 'Namgis First Nation (Alert Bay, British Columbia, Canada) is used to explore the risks and benefits of salmon aquaculture for British Columbia's First Nations. Analysis of interview data (n = 23) indicates strong links between reduced access to environmental resources, marginal participation in the economy, and declining community health and well being. Results suggest that aquaculture development has further decreased the community's access to environmental resources, thereby restricting those economic, social, and cultural activities that determine good health and well-being for this community.

The "click" mechanism in dipteran flight: if it exists, then what effect does it have?

This paper is concerned with the flight mechanism of diptera. For many years it was thought that the flight mechanism incorporated a "click". In recent years, however, doubt has been cast as to whether this exists, or whether it is an artifact of experimental procedure. The aim of this paper is to contribute to this debate by presenting an investigation into the advantages or disadvantages of such a mechanism by conducting a dynamic analysis of a simplified model of such a mechanism. It is shown that, provided the mechanism is driven well below its resonance frequency and it is well-damped, i.e., it does a lot of work, then the flight mechanism with a "click" has distinct advantages over a system that does not have a "click" but is driven at its resonant frequency.