scholarly journals Direct introduction of nitrogen and oxygen functionality with spatial control using copper catalysis

2018 ◽  
Vol 9 (46) ◽  
pp. 8748-8752 ◽  
Author(s):  
James B. Shaum ◽  
David J. Fisher ◽  
Miranda M. Sroda ◽  
Luis Limon ◽  
Javier Read de Alaniz

Synthetic chemists have spent considerable effort optimizing the synthesis of nitrogen and oxygen containing compounds through a number of methods; however, direct introduction of N- and O-functionality remains challenging.

Author(s):  
Dawn A. Bonnell ◽  
Yong Liang

Recent progress in the application of scanning tunneling microscopy (STM) and tunneling spectroscopy (STS) to oxide surfaces has allowed issues of image formation mechanism and spatial resolution limitations to be addressed. As the STM analyses of oxide surfaces continues, it is becoming clear that the geometric and electronic structures of these surfaces are intrinsically complex. Since STM requires conductivity, the oxides in question are transition metal oxides that accommodate aliovalent dopants or nonstoichiometry to produce mobile carriers. To date, considerable effort has been directed toward probing the structures and reactivities of ZnO polar and nonpolar surfaces, TiO2 (110) and (001) surfaces and the SrTiO3 (001) surface, with a view towards integrating these results with the vast amount of previous surface analysis (LEED and photoemission) to build a more complete understanding of these surfaces. However, the spatial localization of the STM/STS provides a level of detail that leads to conclusions somewhat different from those made earlier.


2010 ◽  
Author(s):  
Cynthia Fast ◽  
Dennis Garlick ◽  
Aaron P. Blaisdell

2017 ◽  
Vol 5 (2) ◽  
pp. 215-226
Author(s):  
Kurdish Studies

Andrea Fischer-Tahir and Sophie Wagenhofer (edsF), Disciplinary Spaces: Spatial Control, Forced Assimilation and Narratives of Progress since the 19th Century, Bielefeld: Transcript Verlag, 2017, 300 pp., (ISBN: 978-3-8376-3487-7).Ayşegül Aydın and Cem Emrence, Zones of Rebellion: Kurdish Insurgents and the Turkish State, Ithaca and London: Cornell University Press, 2015, 192 pp., (ISBN: 978-0-801-45354-0).Evgenia I. Vasil’eva, Yugo-Vostochniy Kurdistan v XVI-XIX vv. Istochnik po Istorii Kurdskikh Emiratov Ardelan i Baban. [South-Eastern Kurdistan in the XVI-XIXth cc. A Source for the Study of Kurdish Emirates of Ardalān and Bābān], St Petersburg: Nestor-Istoria, 2016. 176 pp., (ISBN 978-5-4469-0775-5).Karin Mlodoch, The Limits of Trauma Discourse: Women Anfal Survivors in Kurdistan-Iraq, Berlin: Klaus Schwarz Verlag, 2014, 541 pp., (ISBN: 978-3-87997-719-2). 


Author(s):  
R.W. Webby ◽  
W.J. Pengelly

Considerable effort is expended measuring pasture parameters that relate to animal perform mance. Traditionally farmers have used visual impact and experience as their method of pasture assessment to make management decisions. The simplest measurement collected by researchers, pasture height, is developed to the point where it can be used as a guide to predict pasture mass and animal performance. This paper presents relationships between height and mass for improved pastures in summer dry North Island hill country. A pasture 5cm tall will give hogget growth of 60 gjday in summer, 90 in autumn, 100 in winter and 200 in spring. Similarly 5cm will be 2250 kg DM/ha in summer, 1900 in autumn, 1520 in winter, 1640 in spring and 2200 in late spring. Keywords: Height, mass, predictor, grazing, quality, animal performance, feed levels, parameters, pasture.


2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>


2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>


2019 ◽  
Author(s):  
Rémi blieck ◽  
Marc Taillefer ◽  
Florian Monnier

The addition of carboxylic acids to allenes was performed for the first time with copper catalysis. The hydrocarboxylation reaction is totally regio- and stereoselective, ligand-free and used catalytic amounts of copper and base.


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