A review of mathematical models of influenza A infections within a host or cell culture: lessons learned and challenges ahead
Most mathematical models used to study the dynamics of influenza A have thus far focused on the between-host population level, with the aim to inform public health decisions regarding issues such as drug and social distancing intervention strategies, antiviral stockpiling or vaccine distribution. Here, we investigate mathematical modeling of influenza infection spread at a different scale; namely that occurring within an individual host or a cell culture. We review the models that have been developed in the last decades and discuss their contributions to our understanding of the dynamics of influenza infections. We review kinetic parameters (e.g., viral clearance rate, lifespan of infected cells) and values obtained through fitting mathematical models, and contrast them with values obtained directly from experiments. We explore the symbiotic role of mathematical models and experimental assays in improving our quantitative understanding of influenza infection dynamics. We also discuss the challenges in developing better, more comprehensive models for the course of influenza infections within a host or cell culture. Finally, we explain the contributions of such modeling efforts to important public health issues, and suggest future modeling studies that can help to address additional questions relevant to public health., Beauchemin, C. A. A., & Handel, A. (2011). A review of mathematical models of influenza A infections within a host or cell culture: Lessons learned and challenges ahead. BMC Public Health, 11 Suppl 1(Suppl 1), S7-S7. doi:10.1186/1471-2458-11-S1-S7
A simplified cervix model in response to induction balloon in pre-labour
Background: Induction of labour is poorly understood even though it is performed in
20% of births in the United States. One method of induction, the balloon dilator
applied with traction to the interior os of the cervix, engages a softening process,
permitting dilation and effacement to proceed until the beginning of active labour.
The purpose of this work is to develop a simple model capable of reproducing the
dilation and effacement effect in the presence of a balloon.
Methods: The cervix, anchored by the uterus and the endopelvic fascia was modelled
in pre-labour. The spring-loaded, double sliding-joint, double pin-joint mechanism
model was developed with a Modelica-compatible system, MapleSoft MapleSim 6.1,
with a stiff Rosenbrock solver and 1E-4 absolute and relative tolerances. Total
simulation time for pre-labour was seven hours and simulations ended at 4.50 cm
dilation diameter and 2.25 cm effacement.
Results: Three spring configurations were tested: one pin joint, one sliding joint and
combined pin-joint-sliding-joint. Feedback, based on dilation speed modulated the
spring values, permitting controlled dilation. Dilation diameter speed was maintained
at 0.692 cm · hr−1 over the majority of the simulation time. In the sliding-joint-only
mode the maximum spring constant value was 23800 N · m−1. In pin-joint-only the
maximum spring constant value was 0.41 N·m· rad−1.With a sliding-joint-pin-joint pair
the maximum spring constants are 2000 N · m−1 and 0.41 N · m · rad−1, respectively.
Conclusions: The model, a simplified one-quarter version of the cervix, is capable of
maintaining near-constant dilation rates, similar to published clinical observations for
pre-labour. Lowest spring constant values are achieved when two springs are used, but
nearly identical tracking of dilation speed can be achieved with only a pin joint spring.
Initial and final values for effacement and dilation also match published clinical
observations. These results provide a framework for development of electro-mechanical
phantoms for induction training, as well as dilator testing and development., Smith, J. A. (2013). A simplified cervix model in response to induction balloon in pre-labour. Theoretical Biology & Medical Modelling, 10(1), 58-58. doi:10.1186/1742-4682-10-58
A survey of diet self-efficacy and food intake in students with high and low perceived stress.
Given the rise in obesity and obesity-related disorders, understanding the relationship between stress, self-efficacy and food choice in young adulthood may have implications for preventing negative health outcomes later in life that stem from poor eating habits. The current study examined whether stress levels and diet self-efficacy may be associated with unhealthy eating habits in young adults.
Male and female undergraduate students (N = 136) completed questionnaires that tap into diet self-efficacy
(DSE), perceived stress (PS), sodium, and fat intake. Sex differences in choice of food were predicted, and low levels of perceived stress and high diet self-efficacy were expected to be associated with lower fat and sodium intake.
Findings indicate an interaction between perceived stress and diet self-efficacy on fat intake and a main effect for diet self-efficacy on sodium intake in this population. As expected, low levels of perceived stress and high diet
self-efficacy were associated with the lowest levels of fat and sodium intake in students. Findings were driven by females.
This study provides preliminary evidence that diet self-efficacy and perceived stress levels relate to nutrient intake in young adult females, and that increasing diet self-efficacy and reducing perceived stress in young adult females may lead to reductions in fat and sodium intake, leading to healthier eating habits., Nastaskin, R. S., & Fiocco, A. J. (2015). A survey of diet self-efficacy and food intake in students with high and low perceived stress. Nutrition Journal, 14, 42.
A systematic literature review of diabetes self-management education features to improve diabetes education in women of Black African/Caribbean and Hispanic/Latin American ethnicity, Patient Education and Counseling
This systematic literature review aims to identify diabetes self-management education (DSME) features to improve diabetes education for Black African/Caribbean and Hispanic/Latin American women with Type 2 diabetes mellitus.
We conducted a literature search in six health databases for randomized controlled trials and comparative studies. Success rates of intervention features were calculated based on effectiveness in improving glycosolated hemoglobin (HbA1c), anthropometrics, physical activity, or diet outcomes. Calculations of rate differences assessed whether an intervention feature positively or negatively affected an outcome.
From 13 studies included in our analysis, we identified 38 intervention features in relation to their success with an outcome. Five intervention features had positive rate differences across at least three outcomes: hospital-based interventions, group interventions, the use of situational problem-solving, frequent sessions, and incorporating dietitians as interventionists. Six intervention features had high positive rate differences (i.e. ≥50%) on specific outcomes.
Different DSME intervention features may influence broad and specific self-management outcomes for women of African/Caribbean and Hispanic/Latin ethnicity.
With the emphasis on patient-centered care, patients and care providers can consider options based on DSME intervention features for its broad and specific impact on outcomes to potentially make programming more effective., Gucciardi, E., Chan, V., Manuel, L. and Sidani, S. (2013). A systematic literature review of diabetes self-management education features to improve diabetes education in women of Black African/Caribbean and Hispanic/Latin American ethnicity. Patient Education and Counseling, 92(2), pp.235-245.
A systematic review of the effectiveness of advanced practice nurses in long-term care
To report quantitative evidence of the effectiveness of advanced practice nursing roles, clinical nurse specialists and nurse practitioners, in meeting the healthcare needs of older adults living in long-term care residential settings. Although studies have examined the effectiveness of advanced practice nurses in this setting, a systematic review of this evidence has not been conducted. Quantitative systematic review. Twelve electronic databases were searched (1966-2010); leaders in the field were contacted; and personal files, reference lists, pertinent journals, and websites were searched for prospective studies with a comparison group. Studies that met inclusion criteria were reviewed for quality, using a modified version of the Cochrane Effective Practice and Organisation of Care Review Group risk of bias assessment criteria. Four prospective studies conducted in the USA and reported in 15 papers were included. Long-term care settings with advanced practice nurses had lower rates of depression, urinary incontinence, pressure ulcers, restraint use, and aggressive behaviours; more residents who experienced improvements in meeting personal goals; and family members who expressed more satisfaction with medical services. Advanced practice nurses are associated with improvements in several measures of health status and behaviours of older adults in long-term care settings and in family satisfaction. Further exploration is needed to determine the effect of advanced practice nurses on health services use; resident satisfaction with care and quality of life; and the skills, quality of care, and job satisfaction of healthcare staff., Donald, F., Martin‐Misener, R., Carter, N., Donald, E. E., Kaasalainen, S., Wickson‐Griffiths, A.. . DiCenso, A. (2013). A systematic review of the effectiveness of advanced practice nurses in long‐term care. Journal of Advanced Nursing, 69(10), 2148-2161. doi:10.1111/jan.12140
A systematic review of web-based educational interventions
A complement to in-hospital educational interventions is web-based patient education accessed during the home recovery period. While findings demonstrate the effectiveness of web-based patient education interventions on patient outcomes, they fall short of identifying the characteristics that are associated with desired outcomes. The purpose of this systematic review was to determine the characteristics of web-based patient education interventions that are associated with producing changes in self-care behaviours. A systematic review involving 19 studies was conducted to determine the most effective components of a web-based intervention. Findings suggest that the most effective form of web-based patient education is one that is interactive and allows patients to navigate the online system on their own. The findings from this systematic review allow for the design of a web-based educational intervention that will promote increased performance of self-care behaviours during the home recovery period., Fredericks, S., Martorella, G., & Catallo, C. (2015). A systematic review of web-based educational interventions. Clinical Nursing Research, 24(1), 91-113.
A theory of sharecropping: the role of price behavior and imperfect competition
This paper proposes a theory of sharecropping on the basis of price behavior in agriculture and imperfectly competitive nature of rural product markets. We consider a contractual setting between one landlord and one tenant with seasonal variation of price, where the tenant receives a low price for his output while the landlord can sell his output at a higher price by incurring a cost of storage. We consider two different classes of contracts: (i) tenancy contracts and (ii) crop-buying contracts. It is shown that sharecropping is the optimal form within tenancy contracts and it also dominates crop-buying contracts provided the price variation is not too large. Then we consider interlinked contracts that have both tenancy and crop-buying elements and show that there are multiple optimal interlinked contracts. Finally, proposing an equilibrium refinement that incorporates imperfect competition in the rural product market, it is shown that the unique contract that is robust to this refinement results in sharecropping., Also available for download here:
AMP-Activated Protein Kinase Regulates the Cell Surface Proteome and Integrin Membrane Traffic
The cell surface proteome controls numerous cellular functions including cell migration and adhesion, intercellular communication and nutrient uptake. Cell surface proteins are controlled by acute changes in protein abundance at the plasma membrane through regulation of endocytosis and recycling (endomembrane traffic). Many cellular signals regulate endomembrane traffic, including metabolic signaling; however, the extent to which the cell surface proteome is controlled by acute regulation of endomembrane traffic under various conditions remains incompletely understood. AMP-activated protein kinase (AMPK) is a key metabolic sensor that is activated upon reduced cellular energy availability. AMPK activation alters the endomembrane traffic of a few specific proteins, as part of an adaptive response to increase energy intake and reduce energy expenditure. How increased AMPK activity during energy stress may globally regulate the cell surface proteome is not well understood. To study how AMPK may regulate the cell surface proteome, we used cell-impermeable biotinylation to selectively purify cell surface proteins under various conditions. Using ESI-MS/MS, we found that acute (90 min) treatment with the AMPK activator A-769662 elicits broad control of the cell surface abundance of diverse proteins. In particular, A-769662 treatment depleted from the cell surface proteins with functions in cell migration and adhesion. To complement our mass spectrometry results, we used other methods to show that A-769662 treatment results in impaired cell migration. Further, A-769662 treatment reduced the cell surface abundance of β1-integrin, a key cell migration protein, and AMPK gene silencing prevented this effect. While the control of the cell surface abundance of various proteins by A-769662 treatment was broad, it was also selective, as this treatment did not change the cell surface abundance of the transferrin receptor. Hence, the cell surface proteome is subject to acute regulation by treatment with A-769662, at least some of which is mediated by the metabolic sensor AMPK., Ross E, Ata R, Thavarajah T, Medvedev S, Bowden P, Marshall JG, et al. (2015) AMP-Activated Protein Kinase Regulates the Cell Surface Proteome and Integrin Membrane Traffic. PLoS ONE 10(5): e0128013.
Absence of Evidence and Evidence of Absence
This paper appears in Faith and Philosophy 24 (2007): 203-228. The published version can be
found online at: http://www.pdcnet.org/collection/faithphil_2007_0024_0002_0203_0228.pdf .
Academic Librarianship: A Crisis or an Opportunity?
“Academic Librarianship: A Crisis or an Opportunity?" was a one day symposium held at the University of Toronto on November 18, 2011. The symposium provided a forum for stakeholders to consider recent troubling events and developments in the academic library community. The hiring of postdoctoral fellows at McMaster University to replace librarians, the strike by professional librarians at University of Western Ontario in 2011 and threats to the academic freedom of librarians at McGill University have all served as bellwethers and have been rich topics for debate of late. The symposium was intended to provide an opportunity to bring more coherence to the discourse and to consider further initiatives, increased activism, and to begin a process for providing greater leadership around issues relating to academic librarians and academic librarianship. The day was organized around a series of panels. A number of key stakeholders spoke to specific themes: 1) the role of national and provincial labour organizations and local faculty associations; 2) trends and challenges in education and curriculum at library schools; 3) the role of library associations and professional accreditation; and 4) librarians on the front lines. The symposium emerged with a clear call to action: that it is time to become more pro-active in a collective manner, and to use the tremendous interest generated by this event as an opportunity to seek solutions to the challenges facing academic librarianship in Canada. There was overwhelming support for the creation of a virtual forum to continue the discourse and to bring in those who are interested and willing to become engaged but who were unable to participate in the symposium., Partnership: the Canadian Journal of Library and Information Practice and Research, vol. 6, no. 2 (2011).
Also available online at: http://journal.lib.uoguelph.ca/index.php/perj/article/view/1678