Quantifying Electrophoretic Deposition of Nanocrystal Superlattices Using Quartz Crystal Microbalance

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Controlled electrochemical growth of ultra-long gold nanoribbons

Citation: Basnet, G., Panta, K. R., Thapa, P. S., & Flanders, B. N. (2017). Controlled electrochemical growth of ultra-long gold nanoribbons. Applied Physics Letters, 110(7), 5. doi:10.1063/1.4976027This paper describes the electrochemical growth of branchless gold nanoribbons with similar to 40 nm x similar to 300 nm cross sections and >100 mu m lengths (giving length-to-thickness aspect ratios of > 10(3)). These structures are useful for opto-electronic studies and as nanoscale electrodes. The 0.75-1.0V voltage amplitude range is optimal for branchless ribbon growth. Reduced amplitudes induce no growth, possibly due to reversible redox chemistry of gold at reduced amplitudes, whereas elevated amplitudes, or excess electrical noise, induce significant side-branching. The inter-relatedness of voltage-amplitude, noise, and side-branching in electrochemical nanoribbon growth is demonstrated. Published by AIP Publishing

Laser-Induced Electron Emission from Au Nanowires: A Probe for Orthogonal Polarizations

Photoelectron field emission, induced by femtosecond laser pulses focused on metallic nanotips, provides spatially coherent and temporally short electron pulses. The properties of the photoelectron yield give insight into both the material properties of the nanostructure and the exciting laser focus. Ultralong nanoribbons, grown as a single crystal attached to a metallic taper, are sources of electron field emission that have not yet been characterized. In this report, photoemission from gold nanoribbon samples is studied and compared to emission from tungsten and gold tips. We observe that the emission from sharp tips generally depends on one transverse component of the exciting laser field, while the emission of a blunted nanoribbon is found to be sensitive to both components. We propose that this property makes photoemission from nanoribbons a candidate for position-sensitive detection of the longitudinal field component in a tightly focused beam

Blueprints for Green Communities: Climate change visioning and participatory landscape planning for resilient low-carbon communities

Emerging 3D visualization tools and future visioning methods offer new ways to make climate change impacts and potential responses explicit, and accelerate holistic solutions. Previous research at UBC’s Collaborative for Advanced Landscape Planning (CALP) and elsewhere confirms that 4D visioning processes using landscape visualizations of recognizable places under alternative future conditions can improve community engagement and awareness on complex environmental and planning issues (Tress and Tress, 2002; Sheppard and Meitner, 2005; Schroth, 2007). This paper examines a visioning process (Sheppard, 2008) that applies visualization and other landscape planning methods to explore high and low-carbon futures of the affluent, sub-urban hillside community of North Vancouver with climate change, and its surrounding scenic North Shore sub region of Metro Vancouver, BC, Canada

Algebraic analysis of a model of two-dimensional gravity

An algebraic analysis of the Hamiltonian formulation of the model two-dimensional gravity is performed. The crucial fact is an exact coincidence of the Poisson brackets algebra of the secondary constraints of this Hamiltonian formulation with the SO(2,1)-algebra. The eigenvectors of the canonical Hamiltonian $H_{c}$ are obtained and explicitly written in closed form.Comment: 21 pages, to appear in General Relativity and Gravitatio

Impact of Baseline Magnetic Resonance Imaging on Neurologic, Functional, and Safety Outcomes in Patients With Acute Traumatic Spinal Cord Injury

Study Design: Systematic review. Objective: To perform a systematic review to evaluate the utility of magnetic resonance imaging (MRI) in patients with acute spinal cord injury (SCI). Methods: An electronic search of Medline, EMBASE, the Cochrane Collaboration Library, and Google Scholar was conducted for literature published through May 12, 2015, to answer key questions associated with the use of MRI in patients with acute SCI. Results: The literature search yielded 796 potentially relevant citations, 8 of which were included in this review. One study used MRI in a protocol to decide on early surgical decompression. The MRI-protocol group showed improved outcomes; however, the quality of evidence was deemed very low due to selection bias. Seven studies reported MRI predictors of neurologic or functional outcomes. There was moderate-quality evidence that longer intramedullary hemorrhage (2 studies) and low-quality evidence that smaller spinal canal diameter at the location of maximal spinal cord compression and the presence of cord swelling are associated with poor neurologic recovery. There was moderate-quality evidence that clinical outcomes are not predicted by SCI lesion length and the presence of cord edema. Conclusions: Certain MRI characteristics appear to be predictive of outcomes in acute SCI, including length of intramedullary hemorrhage (moderate-quality evidence), canal diameter at maximal spinal cord compression (low-quality evidence), and spinal cord swelling (low-quality evidence). Other imaging features were either inconsistently (presence of hemorrhage, maximal canal compromise, and edema length) or not associated with outcomes. The paucity of literature highlights the need for well-designed prospective studies. © 2017, © The Author(s) 2017

Forces at Individual Pseudopod-Filament Adhesive Contacts

On-chip cellular force sensors are fabricated from cantilever poly(3,4-ethylene dioxythiophene) filaments that visibly deflect under forces exerted at individual pseudopod-filament adhesive contacts. The shape of the deflected filaments and their ∼3 nN/μm spring constants are predicted by cantilever rod theory. Pulling forces exerted by Dictyostelium discoideumcells at these contacts are observed to reach ∼20 nN without breaking the contact