4,297 research outputs found
Point contact studies of rare earth-transition metal compounds
No full textMechanical point contact techniques have been used to study the spin-dependent properties of rare earth-transition metal compounds and transition metal thin films and bi-layers. The transport spin polarisation of Cu, Co and Fe has been measured using point contact Andreev reflection (PCAR), and found to be in good agreement with previous results. In addition, bi-layers of Co/Y and Co/Cu have been used to
demonstrate suppression of the spin polarisation of the Co underlayer via a nonmagnetic capping layer. The spin diffusion length of Cu has been estimated to be larger than 600nm. The spin polarisation of molecular beam epitaxy (MBE) deposited
RFe2 (R = Dy,Y,Er) Laves phase intermetallic films was determined, and found to be close to that of Fe. This suggests that the spin transport behaviour in these materials is
dominated by the Fe sub-lattice. Preliminary evidence for spin transfer torque effects in an RFe2 multilayer and tri-layer is also presented and discussed. Point contact measurements of an ErFe2/YFe2 multilayer at 4.2K show a step in the differential
resistance at a positive current value. It is suggested that this is due to the formation of a nano-domain beneath the tip. Measurements of a DyFe2/YFe2/DyFe2 tri-layer show
peaks in differential resistance for negative applied currents. This is tentatively attributed to the generation of spin waves within the YFe2 layer
Book review: The theatrical public sphere, by Christopher B. Balme
No full textBook review of: The theatrical public sphere, by Christopher B. Balme. Cambridge: Cambridge University Press, 2014; ISBN 9781107006836 (£60.00)Publisher PD
Common greenbrier (Smilax rotundifolia L.) as a model for understanding fungal community organization in the phyllosphere
No full textFungi asymptomatically infect all terrestrial vegetation, but the structure and assembly of these fungal communities are poorly understood. Smilax rotundifolia, a common woody vine of the northeastern United States, was used as a model to study endophytic (internal colonizing) and epiphytic (surface colonizing) fungal communities, from the perspectives of niche-based influences, spatial variation, and evolutionary relationships. Wild greenbrier plants were sampled in New Jersey (USA) in late winter at a single site, and again in mid-summer, in a multi-site, multi-tissue, sampling effort. Fungal communities of the plant surface and interior were made up of mostly different species. Correlative relationships were found between some fungal species' abundances, but none were seen between species that were strongly restricted to the surface and those strongly restricted to the interior. The summer, multi-site study, revealed that the strongest factor determining fungal community composition was surface vs. interior habitat, followed by tissue/organ type, and lastly general geographic location. The effect of season was also studied by comparing the single-site winter dataset against the data from the same site sampled in summer. Season had a major influence on some fungal species but not others, similar to influence of tissue type. Also, in a very novel finding, it was found that certain endophytes showed statistically different abundances, depending on the distance from the stem base at which a sample was taken. The optimum height differed for different fungal species. At the scale of a single stand of plants, it was found that epiphytic, but not endophytic, samples showed a significant correlation between spatial proximity and fungal community similarity. Finally, the phylogenetic relationships were studied between congeneric fungal species that were common on the plant. Two-gene phylogenies were constructed using Smilax-derived isolates, along with downloaded sequences of well-defined species in the same genera. These congeneric species were found to be only distantly related (i.e., they were widely separated within the known phylogenies of their genus). The final chapter is a literature review, bringing insight from the present dissertation research to identify important unanswered questions. Evidence for the role of plant secondary metabolites on endophytic fungi is discussed.Ph.D.Includes bibliographical referencesby Christopher B. Zambel
The Christopher Johnston Family
No full textNotes - Mrs. Daisy Gooding tells the story of her parents’ immigration, marriage and early family life in Athabasca. Her father, Mr. Christopher Johnston, was originally a lay minister and a trader and later opened a bakery in Athabasca with her mother Christine. Mrs. Gooding tells of her parents’ experiences: cooking meals for the North West Mountain Police, dealing with the fire and flu epidemics in the early 1900s, and life in general. She talks of her parents personal and business relationships with many homesteaders as well as First Nation citizens. Many anecdotes are shared including the story of Bill Day and his sleigh pulled by moose. Mrs. Gooding’s father became a ferryman and stories of ferrying on the Athabasca River are part of this tribute to her parents (8 pages
University-affiliated retirement development : a resource for universities
No full textThesis (S.M. in Real Estate Development)--Massachusetts Institute of Technology, Dept. of Architecture, Center for Real Estate, 2004 [first author]; and, (S.M. in Real Estate Development)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, Center for Real Estate, 2004 [second author].This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references.by Christopher B. Helsaback & David B. Ritchey.S.M.in Real Estate Developmen
An orexinergic projection from perifornical hypothalamus to raphe pallidus increases rat brown adipose tissue thermogenesis
No full textOrexin (hypocretin) neurons, located exclusively in the PeF-LH, which includes the perifornical area (PeF), the lateral hypothalamus (LH), and lateral portions of the medial hypothalamus, have widespread projections and influence many physiological functions, including the autonomic regulation of body temperature and energy metabolism. Narcolepsy is characterized by the loss of orexin neurons and by disrupted sleep, but also by dysregulation of body temperature and by a strong tendency for obesity. Heat production (thermogenesis) in brown adipose tissue (BAT) contributes to the maintenance of body temperature and, through energy consumption, to body weight regulation. We identified a neural substrate for the influence of orexin neurons on BAT thermogenesis in rat. Nanoinjection of orexin-A (12 pmol) into the rostral raphe pallidus (rRPa), the site of BAT sympathetic premotor neurons, produced large, sustained increases in BAT sympathetic outflow and in BAT thermogenesis. Activation of neurons in the PeF-LH also enhanced BAT thermogenesis over a long time course. Combining viral retrograde tracing from BAT, or cholera toxin subunit b tracing from rRPa, with orexin immunohistochemistry revealed synaptic connections to BAT from orexin neurons in PeF-LH and from rRPa neurons with closely apposed, varicose orexin fibers, as well as a direct, orexinergic projection from PeF-LH to rRPa. These results indicate a potent modulation of BAT thermogenesis by orexin released from the terminals of orexin neurons in PeF-LH directly into the rRPa and provide a potential mechanism contributing to the disrupted regulation of body temperature and energy metabolism in the absence of orexin. � 2011 the authors
Book review: Better business: how the B Corp movement is remaking capitalism by Christopher Marquis
No full textIn Better Business: How the B Corp Movement is Remaking Capitalism, Christopher Marquis offers a new study of the history of the B Corp movement as well as its goals, international expansion and its struggles, arguing that it has the potential to redefine capitalism based on principles of accountability, performance, standards and transparency. Marquis’s access to the movement and ability to write organisational history make this book a fantastic read, finds Johannes Lenhard. If you are interested in this book, you can watch a video of the author Christopher Marquis discussing the B Corp movement, social impact and impact investing as part of an LSE student event organised by the Marshall Institute and recorded on 3 March 2021. Better Business: How the B Corp Movement is Remaking Capitalism. Christopher Marquis. Yale University Press. 2020
Book review: Better business: how the B Corp movement is remaking capitalism by Christopher Marquis
No full textIn Better Business: How the B Corp Movement is Remaking Capitalism, Christopher Marquis offers a new study of the history of the B Corp movement as well as its goals, international expansion and its struggles, arguing that it has the potential to redefine capitalism based on principles of accountability, performance, standards and transparency. Marquis’s access to the movement and ability to write organisational history make this book a fantastic read, finds Johannes Lenhard. If you are interested in this book, you can watch a video of the author Christopher Marquis discussing the B Corp movement, social impact and impact investing as part of an LSE student event organised by the Marshall Institute and recorded on 3 March 2021. Better Business: How the B Corp Movement is Remaking Capitalism. Christopher Marquis. Yale University Press. 2020
Supporting Data for “Why So Slow? Mechanistic Insights from Studies of a Poor Catalyst for Polymerization of ε-Caprolactone”
No full textThese files contain data along with associated output from instrumentation supporting all results reported in Stasiw, D. E.; Mandal, M.; Neisen, B. D.; Mitchell, L. A.; Cramer, C. J.; Tolman, W. B. Why so slow? Mechanistic insights from studies of a poor catalyst for polymerization of ε-caprolactone. Inorg. Chem., 2016, 56, 725–728. Polymerization of ε-caprolactone (CL) using an aluminum alkoxide catalyst (1) designed to prevent unproductive trans binding was monitored at 110 °C in toluene-d8 by 1H NMR and the concentration versus time data fit to a first-order rate expression. A comparison of t1/2 for 1 to values for many other aluminum alkyl and alkoxide complexes shows much lower activity of 1 toward polymerization of CL. Density functional theory calculations were used to understand the basis for the slow kinetics. The optimized geometry of the ligand framework of 1 was found indeed to make CL trans binding difficult: no trans-bound intermediate could be identified as a local minimum. Nor were local minima for cis-bound precomplexes found, suggesting a concerted coordination–insertion for polymer initiation and propagation. The sluggish performance of 1 is attributed to a high-framework distortion energy required to deform the “resting” ligand geometry to that providing optimal catalysis in the corresponding transition-state structure geometry, thus suggesting a need to incorporate ligand flexibility in the design of efficient polymerization catalysts..
Corresponding author for experimental data is William B. Tolman ([email protected]).
Corresponding author for computational data is Christopher J. Cramer ([email protected]).Funding for this project was provided by the Center for Sustainable Polymers at the University of Minnesota, a National Science Foundation (NSF)-supported Center for Chemical Innovation (Grant CHE-1413862). The X-ray diffraction experiments were performed using a crystal diffractometer acquired through NSF-MRI Award CHE-1229400. The authors acknowledge the MSI at the University of Minnesota for providing resources that contributed to the research results.Tolman, William, B; Cramer, Christopher, J; Stasiw, Daniel E; Mandal, Mukunda; Neisen, Benjamin D; Mitchell, Lauren A. (2017). Supporting Data for “Why So Slow? Mechanistic Insights from Studies of a Poor Catalyst for Polymerization of ε-Caprolactone”. Retrieved from the University Digital Conservancy, https://doi.org/10.13020/D6F60H
α2 adrenergic receptor-mediated inhibition of thermogenesis
No full text�2 adrenergic receptor (�2-AR) agonists have been used as antihypertensive agents, in the management of drug withdrawal, and as sedative analgesics. Since �2-AR agonists also influence the regulation of body temperature, we explored their potential as antipyretic agents. This study delineates the central neural substrate for the inhibition of rat brown adipose tissue (BAT) and shivering thermogenesis by �2-AR agonists. Nanoinjection of the �2-AR agonist clonidine (1.2 nmol) into the rostral raphe pallidus area (rRPa) inhibited BAT sympathetic nerve activity (SNA) and BAT thermogenesis. Subsequent nanoinjection of the �2-AR antagonist idazoxan (6 nmol) into the rRPa reversed the clonidine-evoked inhibition of BAT SNA and BAT thermogenesis. Systemic administration of the �2-AR agonists dexmedetomidine (25 �g/kg, i.v.) and clonidine (100 �g/kg, i.v.) inhibited shivering EMGs, BAT SNA, and BAT thermogenesis, effects that were reversed by nanoinjection of idazoxan (6 nmol) into the rRPa. Dexmedetomidine (100 �g/kg, i.p.) prevented and reversed lipopolysaccharide-evoked (10 �g/kg, i.p.) thermogenesis in free-behaving rats. Cholera toxin subunit b retrograde tracing from rRPa and pseudorabies virus transynaptic retrograde tracing from BAT combined with immunohistochemistry for catecholaminergic biosynthetic enzymes revealed the ventrolateral medulla as the source of catecholaminergic input to the rRPa and demonstrated that these catecholaminergic neurons are synaptically connected to BAT. Photostimulation of ventrolateral medulla neurons expressing the PRSx8- ChR2-mCherry lentiviral vector inhibited BAT SNA via activation of 2-ARs in the rRPa. These results indicate a potent inhibition of BAT and shivering thermogenesis by �2-AR activation in the rRPa, and suggest a therapeutic potential of �2-AR agonists for reducing potentially lethal elevations in body temperature during excessive fever. � 2013 the authors
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