355 research outputs found
Deoxyfluorination of (Hetero)aryl Aldehydes Using Tetramethylammonium Fluoride and Perfluorobutanesulfonyl Fluoride or Trifluoromethanesulfonic Anhydride
This Communication describes the conversion of (hetero)aryl aldehydes into the corresponding (hetero)aryl difluoromethyl products using anhydrous NMe4F in combination with perfluorobutanesulfonyl fluoride or trifluoromethanesulfonic anhydride.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154980/1/ijch201900066-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154980/2/ijch201900066_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154980/3/ijch201900066.pd
Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae)
Background: Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. Results: 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. Conclusions: The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.Fil: Burke, Sean V.. Northern Illinois University; Estados UnidosFil: Wysocki, William P.. Northern Illinois University; Estados UnidosFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, FĂsicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Craine, Joseph M.. Jonah Ventures; Estados UnidosFil: Pires, J. Chris. University of Missouri; Estados UnidosFil: Edger, Patrick P.. Michigan State University; Estados UnidosFil: Mayfield Jones, Dustin. Donald Danforth Plant Science Center; Estados UnidosFil: Clark, Lynn G.. Iowa State University; Estados UnidosFil: Kelchner, Scot A.. University of Idaho; Estados UnidosFil: Duvall, Melvin R.. Northern Illinois University; Estados Unido
Resolving deep relationships of PACMAD grasses: a phylogenomic approach
Background
Plastome sequences for 18 species of the PACMAD grasses (subfamilies Panicoideae, Aristidoideae, Chloridoideae, Micrairoideae, Arundinoideae, Danthonioideae) were analyzed phylogenomically. Next generation sequencing methods were used to provide complete plastome sequences for 12 species. Sanger sequencing was performed to determine the plastome of one species, Hakonechloa macra, to provide a reference for annotation. These analyses were conducted to resolve deep subfamilial relationships within the clade. Divergence estimates were assessed to determine potential factors that led to the rapid radiation of this lineage and its dominance of warmer open habitats.
Results
New plastomes were completely sequenced and characterized for 13 PACMAD species. An autapomorphic ~1140 bp deletion was found in Hakonechloa macra putatively pseudogenizing rpl14 and eliminating rpl16 from this plastome. Phylogenomic analyses support Panicoideae as the sister group to the ACMAD clade. Complete plastome sequences provide greater support at deep nodes within the PACMAD clade. The initial diversification of PACMAD subfamilies was estimated to occur at 32.4 mya.
Conclusions
Phylogenomic analyses of complete plastomes provides resolution for deep relationships of PACMAD grasses. The divergence estimate of 32.4 mya at the crown node of the PACMAD clade coincides with the Eocene-Oligocene Transition (EOT). The Eocene was a period of global cooling and drying, which led to forest fragmentation and the expansion of open habitats now dominated by these grasses. Understanding how these grasses are related and determining a cause for their rapid radiation allows for future predictions of grassland distribution in the face of a changing global climate.This work was supported in part by the Plant Molecular Biology Center, the Department of Biological Sciences at Northern Illinois University and the National Science Foundation under Grant Numbers DEB-1120750 to LGC, DEB-1120856 to SAK and DEB-1120761 to MRD.This article is made openly accessible in part by an award from the Northern Illinois University Libraries’ Open Access Publishing Fund
Stabilizing Peri-Stent Restenosis Using a Novel Therapeutic Carrier
Late in-stent restenosis remains a significant problem. Bare-metal stents were implanted into peripheral arteries in miniature swine, followed by direct intra-arterial infusion of nitric oxide-loaded echogenic liposomes (ELIPs) and anti-intercellular adhesion molecule-1 conjugated ELIPs loaded with pioglitazone exposed to an endovascular catheter with an ultrasonic core. Ultrasound-facilitated delivery of ELIP formulations into stented peripheral arteries attenuated neointimal growth. Local atheroma-targeted, ultrasound-triggered delivery of nitric oxide and pioglitazone, an anti-inflammatory peroxisome proliferator-activated receptor-Îł agonist, into stented arteries has the potential to stabilize stent-induced neointimal growth and obviate the need for long-term antiplatelet therapy
Discrete Routh Reduction
This paper develops the theory of abelian Routh reduction for discrete
mechanical systems and applies it to the variational integration of mechanical
systems with abelian symmetry. The reduction of variational Runge-Kutta
discretizations is considered, as well as the extent to which symmetry
reduction and discretization commute. These reduced methods allow the direct
simulation of dynamical features such as relative equilibria and relative
periodic orbits that can be obscured or difficult to identify in the unreduced
dynamics. The methods are demonstrated for the dynamics of an Earth orbiting
satellite with a non-spherical correction, as well as the double
spherical pendulum. The problem is interesting because in the unreduced
picture, geometric phases inherent in the model and those due to numerical
discretization can be hard to distinguish, but this issue does not appear in
the reduced algorithm, where one can directly observe interesting dynamical
structures in the reduced phase space (the cotangent bundle of shape space), in
which the geometric phases have been removed. The main feature of the double
spherical pendulum example is that it has a nontrivial magnetic term in its
reduced symplectic form. Our method is still efficient as it can directly
handle the essential non-canonical nature of the symplectic structure. In
contrast, a traditional symplectic method for canonical systems could require
repeated coordinate changes if one is evoking Darboux' theorem to transform the
symplectic structure into canonical form, thereby incurring additional
computational cost. Our method allows one to design reduced symplectic
integrators in a natural way, despite the noncanonical nature of the symplectic
structure.Comment: 24 pages, 7 figures, numerous minor improvements, references added,
fixed typo
Electrocardiographic Deep Learning for Predicting Post-Procedural Mortality
Background. Pre-operative risk assessments used in clinical practice are
limited in their ability to identify risk for post-operative mortality. We
hypothesize that electrocardiograms contain hidden risk markers that can help
prognosticate post-operative mortality. Methods. In a derivation cohort of
45,969 pre-operative patients (age 59+- 19 years, 55 percent women), a deep
learning algorithm was developed to leverage waveform signals from
pre-operative ECGs to discriminate post-operative mortality. Model performance
was assessed in a holdout internal test dataset and in two external hospital
cohorts and compared with the Revised Cardiac Risk Index (RCRI) score. Results.
In the derivation cohort, there were 1,452 deaths. The algorithm discriminates
mortality with an AUC of 0.83 (95% CI 0.79-0.87) surpassing the discrimination
of the RCRI score with an AUC of 0.67 (CI 0.61-0.72) in the held out test
cohort. Patients determined to be high risk by the deep learning model's risk
prediction had an unadjusted odds ratio (OR) of 8.83 (5.57-13.20) for
post-operative mortality as compared to an unadjusted OR of 2.08 (CI 0.77-3.50)
for post-operative mortality for RCRI greater than 2. The deep learning
algorithm performed similarly for patients undergoing cardiac surgery with an
AUC of 0.85 (CI 0.77-0.92), non-cardiac surgery with an AUC of 0.83
(0.79-0.88), and catherization or endoscopy suite procedures with an AUC of
0.76 (0.72-0.81). The algorithm similarly discriminated risk for mortality in
two separate external validation cohorts from independent healthcare systems
with AUCs of 0.79 (0.75-0.83) and 0.75 (0.74-0.76) respectively. Conclusion.
The findings demonstrate how a novel deep learning algorithm, applied to
pre-operative ECGs, can improve discrimination of post-operative mortality
SP701-A-Growing and Harvesting Switchgrass for Ethanol Production in Tennessee
Switchgrass is a warm-season perennial grass native to North America. The plant can reach heights up to 10 feet with an extensive root system. Once established, switchgrass well-managed for biomass should have a productive life of 10-20 years. Within the stand, switchgrass is an extremely strong competitor. However, it is not considered an invasive plant. Switchgrass adapts well to a variety of soil and climatic conditions. It is most productive on moderately well to well-drained soils of medium fertility and a soil pH at 5.0 or above. The high cellulosic content of switchgrass makes it a favorable feedstock for ethanol production. It is anticipated that switchgrass can yield sufficient biomass to produce approximately 500 gallons of ethanol per acre. While the Tennessee Biofuels Initiative includes a demonstration plant to make ethanol from switchgrass, the market for switchgrass as an energy crop remains limited. Producers will likely need to be located within 30 to 50 miles of a cellulosic ethanol plant. Producing switchgrass for energy generally occurs under some form of contractual arrangement with the end-user. To reap potential benefits from using switchgrass for cellulosic ethanol production, the system of production must be profitable for farmers and energy producers, as well as cost effective for consumers
Quaternary Organic Solar Cells Enhanced by Cocrystalline Squaraines with Power Conversion Efficiencies >10%
The incorporation of multiple donors into the bulk-heterojunction layer of organic polymer solar cells (PSCs) has been demonstrated as a practical and elegant strategy to improve photovoltaics performance. However, it is challenging to successfully design and blend multiple donors, while minimizing unfavorable interactions (e.g., morphological traps, recombination centers, etc.). Here, a new Förster resonance energy transfer-based design is shown utilizing the synergistic nature of three light active donors (two small molecules and a high-performance donor–acceptor polymer) with a fullerene acceptor to create highly efficient quaternary PSCs with power conversion efficiencies (PCEs) of up to 10.7%. Within this quaternary architecture, it is revealed that the addition of small molecules in low concentrations broadens the absorption bandwidth, induces cocrystalline molecular conformations, and promotes rapid (picosecond) energy transfer processes. These results provide guidance for the design of multiple-donor systems using simple processing techniques to realize single-junction PSC designs with unprecedented PCEs
Quaternary Organic Solar Cells Enhanced by Cocrystalline Squaraines with Power Conversion Efficiencies >10%
The incorporation of multiple donors into the bulk-heterojunction layer of organic polymer solar cells (PSCs) has been demonstrated as a practical and elegant strategy to improve photovoltaics performance. However, it is challenging to successfully design and blend multiple donors, while minimizing unfavorable interactions (e.g., morphological traps, recombination centers, etc.). Here, a new Förster resonance energy transfer-based design is shown utilizing the synergistic nature of three light active donors (two small molecules and a high-performance donor–acceptor polymer) with a fullerene acceptor to create highly efficient quaternary PSCs with power conversion efficiencies (PCEs) of up to 10.7%. Within this quaternary architecture, it is revealed that the addition of small molecules in low concentrations broadens the absorption bandwidth, induces cocrystalline molecular conformations, and promotes rapid (picosecond) energy transfer processes. These results provide guidance for the design of multiple-donor systems using simple processing techniques to realize single-junction PSC designs with unprecedented PCEs
Neuromatch Academy: Teaching Computational Neuroscience with global accessibility
Neuromatch Academy designed and ran a fully online 3-week Computational
Neuroscience summer school for 1757 students with 191 teaching assistants
working in virtual inverted (or flipped) classrooms and on small group
projects. Fourteen languages, active community management, and low cost allowed
for an unprecedented level of inclusivity and universal accessibility.Comment: 10 pages, 3 figures. Equal contribution by the executive committee
members of Neuromatch Academy: Tara van Viegen, Athena Akrami, Kate Bonnen,
Eric DeWitt, Alexandre Hyafil, Helena Ledmyr, Grace W. Lindsay, Patrick
Mineault, John D. Murray, Xaq Pitkow, Aina Puce, Madineh Sedigh-Sarvestani,
Carsen Stringer. and equal contribution by the board of directors of
Neuromatch Academy: Gunnar Blohm, Konrad Kording, Paul Schrater, Brad Wyble,
Sean Escola, Megan A. K. Peter
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