High-throughput Molecular Simulations into the Morphology of P3HT:PCBM Blends

The goal of this research is to understand how temperature, solvent quality, solvent amount, and the concentrations of organic photovoltaic (OPV) components determine active layer morphology. This understanding will improve techniques for engineering OPV devices, which can be inexpensively processed from abundant materials but presently suffer from low photoconversion efficiencies. We perform molecular dynamics (MD) simulations using HOOMD-Blue accelerated with graphics processing units (GPUs) to quantify how individual molecules self-assemble into structures that influence power conversion efficiency. We simulate blends of poly(3-hexylthiophene-2,5-diyl) (P3HT) with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), three of the most important molecules in OPVs. By screening hundreds of combinations of concentration, temperature, and solvent properties, we can identify the conditions that optimize their self-organization. We quantify the degree of order in the predicted morphologies with radial distribution functions, structure factors, and simulated diffraction patterns. We find morphologies in agreement with prior experimental and theoretical work, and offer suggestions for future combinatorial studies

Patient and Technique Survival among a Canadian Multicenter Nocturnal Home Hemodialysis Cohort

Background and objectives: As a result of improved clinical and quality-of-life outcomes compared with conventional hemodialysis, interest in nocturnal home hemodialysis (NHD) has steadily increased in the past decade; however, little is known about the flow of patients through NHD programs or about patient-specific predictors of mortality or technique failure associated with this modality. This study addressed this gap in knowledge

Different forms of glycine- and GABAᴀ-receptor mediated inhibitory synaptic transmission in mouse superficial and deep dorsal horn neurons

Background: Neurons in superficial (SDH) and deep (DDH) laminae of the spinal cord dorsal horn receive sensory information from skin, muscle, joints and viscera. In both regions, glycine- (GlyR) and GABAᴀ-receptors (GABAᴀRs) contribute to fast synaptic inhibition. For rat, several types of GABAᴀR coexist in the two regions and each receptor type provides different contributions to inhibitory tone. Recent work in mouse has discovered an additional type of GlyR, (containing alpha 3 subunits) in the SDH. The contribution of differing forms of the GlyR to sensory processing in SDH and DDH is not understood. Methods and Results: Here we compare fast inhibitory synaptic transmission in mouse (P17-37) SDH and DDH using patch-clamp electrophysiology in transverse spinal cord slices (L3-L5 segments, 23°C). GlyR-mediated mIPSCs were detected in 74% (25/34) and 94% (25/27) of SDH and DDH neurons, respectively. In contrast, GABAᴀR-mediated mIPSCs were detected in virtually all neurons in both regions (93%, 14/15 and 100%, 18/18). Several Gly- and GABAᴀR properties also differed in SDH vs. DDH. GlyR-mediated mIPSC amplitude was smaller (37.1 ± 3.9 vs. 64.7 ± 5.0 pA; n = 25 each), decay time was slower (8.5 ± 0.8 vs. 5.5 ± 0.3 ms), and frequency was lower (0.15 ± 0.03 vs. 0.72 ± 0.13 Hz) in SDH vs. DDH neurons. In contrast, GABAᴀR-mediated mIPSCs had similar amplitudes (25.6 ± 2.4, n = 14 vs. 25. ± 2.0 pA, n = 18) and frequencies (0.21 ± 0.08 vs. 0.18 ± 0.04 Hz) in both regions; however, decay times were slower (23.0 ± 3.2 vs. 18.9 ± 1.8 ms) in SDH neurons. Mean single channel conductance underlying mIPSCs was identical for GlyRs (54.3 ± 1.6 pS, n = 11 vs. 55.7 ± 1.8, n = 8) and GABAᴀRs (22.7 ± 1.7 pS, n = 10 vs. 22.4 ± 2.0 pS, n = 11) in both regions. We also tested whether the synthetic endocanabinoid, methandamide (methAEA), had direct effects on Gly- and GABAᴀRs in each spinal cord region. MethAEA (5 μM) reduced GlyR-mediated mIPSC frequency in SDH and DDH, but did not affect other properties. Similar results were observed for GABAᴀR mediated mIPSCs, however, rise time was slowed by methAEA in SDH neurons. Conclusion: Together these data show that Gly- and GABAᴀRs with clearly differing physiological properties and cannabinoid-sensitivity contribute to fast synaptic inhibition in mouse SDH and DDH

Effects of Watershed Changes on Streamflow: Water Resources Symposium, Number Two

Center for Water and the Environmen