Thoughts about disordered thinking: measuring and quantifying the laws of order and disorder

Peer ReviewedPostprint (author's final draft

Coupling between downstream variations of channel width and local pool–riffle bed topography

A potential control of downstream channel width variations on the structure and planform of pool–riffle sequence local bed topography is a key to the dynamics of gravel bed rivers. How established pool–riffle sequences respond to time-varying changes in channel width at specific locations, however, is largely unexplored and challenging to address with field-based study. Here, we report results of a flume experiment aimed at building understanding of how statistically steady pool–riffle sequence profiles adjust to spatially prescribed channel width changes. We find that local bed slopes near steady-state conditions inversely correlate with local downstream width gradients when the upstream sediment supply approximates the estimated transport capacity. This result constrains conditions prior to and following the imposed local width changes. Furthermore, this relationship between local channel bed slope and downstream width gradient is consistent with expectations from scaling theory and a broad set of field-based, numerical, and experimental studies (n=88). However, upstream disruptions to coarse sediment supply through actions such as dam removal can result in a transient flipping of the expected inverse correlation between bed slope and width gradient, collectively highlighting that understanding local conditions is critical before typically implemented spatial averaging schemes can be reliably applied.Postprint (published version

Functionalization of PLLA with Polymer Brushes to Trigger the Assembly of Fibronectin into Nanonetworks

[EN] Poly-l-lactic acid (PLLA) has been used as a biodegradable polymer for many years; the key characteristics of this polymer make it a versatile and useful resource for regenerative medicine. However, it is not inherently bioactive. Thus, here, a novel process is presented to functionalize PLLA surfaces with poly(ethyl acrylate) (PEA) brushes to provide biological functionality through PEA's ability to induce spontaneous organization of the extracellular matrix component fibronectin (FN) into physiological-like nanofibrils. This process allows control of surface biofunctionality while maintaining PLLA bulk properties (i.e., degradation profile, mechanical strength). The new approach is based on surface-initiated atomic transfer radical polymerization, which achieves a molecularly thin coating of PEA on top of the underlying PLLA. Beside surface characterization via atomic force microscopy, X-ray photoelectron spectroscopy and water contact angle to measure PEA grafting, the biological activity of this surface modification is investigated. PEA brushes trigger FN organization into nanofibrils, which retain their ability to enhance adhesion and differentiation of C2C12 cells. The results demonstrate the potential of this technology to engineer controlled microenvironments to tune cell fate via biologically active surface modification of an otherwise bioinert biodegradable polymer, gaining wide use in tissue engineering applications.The authors acknowledge the EPSRC (EP/P001114/1) and MRC (MR/S005412/1) funding. The authors also acknowledge the EPSRC funding as part of the Doctoral Training Centre EP/F500424/1. This work was also funded by a grant from the UK Regenerative Medicine Platform. X-ray photoelectron spectroscopy was conducted by the National EPSRC XPS Users' Service (NEXUS), Newcastle.Sprott, MR.; Ferrer, G.; Dalby, MJ.; Salmerón Sánchez, M.; Cantini, M. (2019). Functionalization of PLLA with Polymer Brushes to Trigger the Assembly of Fibronectin into Nanonetworks. Advanced Healthcare Materials (Online). 8(3):1-12. https://doi.org/10.1002/adhm.201801469S11283A. J. Rincon Lasprilla G. A. Rueda Martinez B. H. Lunelli J. E. Jaimes Figueroa A. L. Jardini R. Maciel Filho Chem. Eng. Trans 2011 985Khan, F., Tanaka, M., & Ahmad, S. R. (2015). Fabrication of polymeric biomaterials: a strategy for tissue engineering and medical devices. Journal of Materials Chemistry B, 3(42), 8224-8249. doi:10.1039/c5tb01370dXu, F. J., Yang, X. C., Li, C. Y., & Yang, W. T. (2011). Functionalized Polylactide Film Surfaces via Surface-Initiated ATRP. Macromolecules, 44(7), 2371-2377. doi:10.1021/ma200160hKhan, F., & Tanaka, M. (2017). Designing Smart Biomaterials for Tissue Engineering. 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Anticoagulant Surface of 316 L Stainless Steel Modified by Surface-Initiated Atom Transfer Radical Polymerization. ACS Applied Materials & Interfaces, 3(5), 1675-1680. doi:10.1021/am200215xIgnatova, M., Voccia, S., Gilbert, B., Markova, N., Mercuri, P. S., Galleni, M., … Jérôme, C. (2004). Synthesis of Copolymer Brushes Endowed with Adhesion to Stainless Steel Surfaces and Antibacterial Properties by Controlled Nitroxide-Mediated Radical Polymerization. Langmuir, 20(24), 10718-10726. doi:10.1021/la048347tTaran, E., Donose, B., Higashitani, K., Asandei, A. D., Scutaru, D., & Hurduc, N. (2006). ATRP grafting of styrene from benzyl chloride functionalized polysiloxanes: An AFM and TGA study of the Cu(0)/bpy catalyst. European Polymer Journal, 42(1), 119-125. doi:10.1016/j.eurpolymj.2005.06.030Liu, F., Du, C.-H., Zhu, B.-K., & Xu, Y.-Y. (2007). 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Improving the Management of Late-Life Depression in Primary Care: Barriers and Facilitators

The objectives of this study were to elicit Canadian health professionals' views on the barriers to identifying and treating late-life depression in primary care settings and on the solutions felt to be most important and feasible to implement. A consensus development process was used to generate, rank, and discuss solutions. Twenty-three health professionals participated in the consensus process. Results were analysed using quantitative and qualitative methods. Participants generated 12 solutions. One solution, developing mechanisms to increase family physicians' awareness of resources, was highly ranked for importance and feasibility by most participants. Another solution, providing family physicians with direct mental health support, was highly ranked as important but not as feasible by most participants. Deliberations emphasized the importance of case specific, as needed support based on the principles of shared care. The results suggest that practitioners highly value collaborative care but question the feasibility of implementing these principles in current Canadian primary care contexts

Smoke-free air laws and quit attempts: evidence for a moderating role of spontaneous self-affirmation

Background: In addition to their primary goal of protecting nonsmokers from secondhand smoke, smoke-free air laws may also encourage intentions to quit smoking, quit attempts, and cessation among smokers. However, laws may not encourage quitting if smokers feel threatened by them and react defensively. Objective: This study examined whether spontaneous self-affirmation - the extent to which people think about their values or strengths when they feel threatened - may reduce smokers' reactance to smoke-free laws, enhancing the ability of the laws to encourage quitting. Method: We linked state-level information on the comprehensiveness of U.S. smoke-free laws (compiled in January, 2013 by the American Lung Association) with data from a U.S. health survey (Health Information National Trends Survey) collected from September-December, 2013 (N = 345 current smokers; 587 former smokers). Results: Smoke-free laws interacted with self-affirmation to predict quit attempts in the past year and intentions to quit in the next six months: Smokers higher in self-affirmation reported more quit attempts and quit intentions if they lived in states with more comprehensive smoke-free laws. There was some evidence of a "boomerang" effect (i.e., less likelihood of making a quit attempt) among smokers low in self-affirmation if living in states with more comprehensive smoke-free laws, but this effect was significant only among smokers extremely low in self-affirmation. For quit intentions, there was no evidence for a boomerang effect of smoke-free laws even among smokers extremely low in self-affirmation. More comprehensive smoke-free laws were not associated with smoking status (former vs. current smoker) or average amount smoked per day, nor did they interact with self-affirmation to predict these outcomes. Conclusions: The impact of smoke-free policies on quit attempts and quit intentions may be moderated by psychological characteristics such as the tendency to spontaneously self-affirm. Follow-ups should experimentally manipulate self-affirmation and examine effects of smoke-free laws in controlled contexts