1,650 research outputs found
Solvent-free selective epoxidation of cyclooctene using supported gold catalysts
No full textOxidation is one of the major pathways for the synthesis of chemical intermediates. The epoxidation of alkenes by the electrophilic addition of oxygen to a carbon-carbon double bond remains one of the most significant challenges in oxidation. Of key importance is the use of oxygen as the oxidant, but in many cases more reactive, and less green, sources of oxygen are used. We report the solvent-free epoxidation of cyclooctene with air using supported gold catalysts with small amounts of a hydroperoxide. We identify the appropriate reaction conditions to maximize the selectivity of the epoxide. In the absence of a hydroperoxide initiator, using air at atmospheric pressure, no reaction is observed. Choice of the peroxide initiator is crucial and in the absence of a catalyst or a support the reaction of the alkene can be observed with di-t-butyl peroxide and t-butyl hydroperoxide (TBHP) only when high concentrations are used at high temperatures ≥ 80°C, and TBHP was found to be the more selective to epoxide formation. In contrast, cumene hydroperoxide was highly reactive under all conditions evaluated. TBHP was selected for more detailed study. Use of graphite as a support was found to give the best combination of selectivity and conversion. In general the selectivity to the epoxide increased with reaction temperature from 60-80°C and was highest at 80°C. Other carbon supports, e.g. activated carbon, were found to be less effective. TiO2- and SiO2-supported Au catalysts were also selective for the epoxidation reaction and the general order of activity was: graphite > SiO2 > TiO2. The major by-product is the allylic alcohol and the reaction pathways to the epoxides and the allylic alcohol are discussed. Preparation of catalysts using a sol-immobilisation method significantly enhanced catalyst activity with retention of selectivity to the epoxide. © 2009 The Royal Society of Chemistry
Characterization and structure in the development of Tudor comedy
No full textThe role of characterization in dramatic structure is assessed by theoretical criteria.
Characters who perform actions necessary for the completion of the narrative sequence are
said to be "bound" to the narrative; those without such obligations are "free". Characters
who maintain a single, constant meaning during the course of a play are said to be "static";
characters who change or develop into new roles are "dynamic". Horatian decorum
demanded that comic characters be static, and the characters of Plautine and Terentian
tradition were almost always bound to narrative intrigue. However, evaluations of six
Tudor comedies show an increasing use of non-classical characterization within the comic
form.
In the early comedies lohan lohan and Roister Doister all characters are bound and
static, yet the impetus to enlarge the role of characterization is evident. The characters of
lohan lohan are expanded from their French source, and Roister Doister includes
extraneous episodes in which Udall displays his braggart hero. Free characters abound in
Misogonus; as well the play brings dynamic characterization into the scope of comedy with
the conversion of its prodigal son.
Free characters offer new possibilities of non-narrative plotting. In comedies of the
1580s favourite traditional characters appear as diversions outside the action, and thematic
arrangements of characters inform the increasingly complex plots. Lyly stresses the
symbolic potential of characters in Endimion, whereas Greene uses dynamic
characterization to heighten the illusion of independent figures in Friar Bacon and Friar
Bungay. Love's Labour's Lost exposes the limitations of comic artifice by pulling the
characters between convention and individualization.
By the end of the sixteenth century free and dynamic characters had become
common, and characterization had established a sizable claim on the design of English
comedy. These developments set the English form apart from its neoclassical counterparts
Reintroducing Bunky at 125: E.M. Jellinek’s life and contributions to Alcohol Studies
No full textObjective:
Elvin Morton Jellinek (1890–1963) was one of the founders of modern addiction science. This overview is a brief survey of his life and achievements, intended to re-introduce alcohol scholars to his contributions (and possible failings) as well as stimulate interest and historical research in the field.
Method:
The article draws largely from the archival collection of the Rutgers Center of Alcohol Studies (CAS) Library and the Jellinek memorial issue of the CAS Information Services Newsletter. Scholarly works and personal and institutional records by or about E. M. Jellinek were assembled and, when necessary, translated into English.
Results:
Born in 1890 in New York and raised in Hungary, Jellinek studied at several European universities and worked for various institutions and organizations in Budapest (1914–1920), Sierra Leone, Honduras, and at the Worcester State Hospital, in Massachusetts. In 1941 he became an associate professor of applied physiology at Yale University, where he directed the Yale Summer School of Alcohol Studies from 1941 to 1950. After more than a decade of work with the World Health Organization and several Canadian institutions, he taught and conducted research at the Institute for the Study of Human Problems at Stanford University until his death in 1963. Jellinek was a pioneer in research on the nature and causes of alcoholism and was an early proponent of the disease theory of alcoholism.
Conclusions:
With the help of E. M. Jellinek, the modern era of addiction science was launched with an international outlook that included critical attention to the physical infrastructure and intellectual capital needed to form an interdisciplinary field of basic research, applied science, and clinical practice.Peer reviewe
First Impression: An Interview With Author and Bibliophile Nicholas A. Basbanes
No full textNicholas A. Basbanes did not publish his first book until he was 52 but, in the ten years since, the former literary editor at the Worcester Sunday Telegram has given bibliophiles and librarians five books about books. The first, A Gentle Madness: Bibliophiles, Bibliomanes, and the Eternal Passion for Books (Holt, 1995), was a landmark commentary on book collecting that has sold 100,000 copies. The second, Patience & Fortitude (HarperCollins, 2001), named for the pair of lions that guard the entrance to the New York Public Library, explored the ways librarians and collectors have protected and housed their treasures throughout history, while describing libraries and book culture in general. Next came Among the Gently Mad: Strategies and Perspectives for the Book-Hunter in the 21st Century (Holt, 2002), a spin-off book from the first book. Arriving after that was A Splendor of Letters: The Permanence of Books in an Impermanent World (HarperCollins, 2003), an expanded section intended for Patience & Fortitude that looked at how books are preserved for succeeding generations. Borrowing from Ranganathan's third law of library science, Basbanes' recent book, Every Book Its Reader (HarperCollins, 2005), allowed him to draw on numerous taped interviews conducted for A Gentle Madness that were never used. His next work will be a centennial history of Yale University Press. The Lowell, Massachusetts, native spoke at Indiana University as a guest of its Medieval Studies Institute in October 2005, when William F. Meehan III sat down with the author at the Grant Street Inn in Bloomington
First Impression: An Interview With Author and Bibliophile Nicholas A. Basbanes
No full textNicholas A. Basbanes did not publish his first book until he was 52 but, in the ten years since, the former literary editor at the Worcester Sunday Telegram has given bibliophiles and librarians five books about books. The first, A Gentle Madness: Bibliophiles, Bibliomanes, and the Eternal Passion for Books (Holt, 1995), was a landmark commentary on book collecting that has sold 100,000 copies. The second, Patience & Fortitude (HarperCollins, 2001), named for the pair of lions that guard the entrance to the New York Public Library, explored the ways librarians and collectors have protected and housed their treasures throughout history, while describing libraries and book culture in general. Next came Among the Gently Mad: Strategies and Perspectives for the Book-Hunter in the 21st Century (Holt, 2002), a spin-off book from the first book. Arriving after that was A Splendor of Letters: The Permanence of Books in an Impermanent World (HarperCollins, 2003), an expanded section intended for Patience & Fortitude that looked at how books are preserved for succeeding generations. Borrowing from Ranganathan's third law of library science, Basbanes' recent book, Every Book Its Reader (HarperCollins, 2005), allowed him to draw on numerous taped interviews conducted for A Gentle Madness that were never used. His next work will be a centennial history of Yale University Press. The Lowell, Massachusetts, native spoke at Indiana University as a guest of its Medieval Studies Institute in October 2005, when William F. Meehan III sat down with the author at the Grant Street Inn in Bloomington
Oxidation of benzyl alcohol by using gold nanoparticles supported on ceria foam
No full textThe efficacy of using cerium oxide foams as a support for Au nanoparticles and subsequent use as oxidation catalysts have been investigated. These were synthesized using L-asparagine to produce a cerium coordination polymer foam, which was calcined to give the oxide foam. Au nanoparticles were supported on the CeO2 foams using a sol-immobilization method. The activity of the Au/foamCeO2 for solvent-free benzyl alcohol oxidation was superior to standard Au/CeO2 catalysts, and the activity was found to be dependent on the crystallization time of the precursor foam. A crystallization time of 4 h was found to produce the most active catalyst, which retained activity and a high selectivity to benzaldehyde (ca. 96 %) when re-used and this is related to the structure of the material. The high activity is attributed to the greater lability of surface oxygen in the support compared with commercial CeO2 materials. Tailored foam bed: Cerium oxide with a foam morphology is used as a support for gold nanoparticles. The foams are synthesized using L-asparagine to produce a cerium coordination polymer foam, which is calcined to give the oxide foam. The activity of the Au/foamCeO 2 for solvent-free benzyl alcohol oxidation is superior to standard Au/CeO2 catalysts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
The selective oxidation of 1,2-propanediol by supported gold-based nanoparticulate catalysts
No full textThe oxidation of 1,2-propanediol to form lactic acid and hydroxyacetone has been investigated using supported metal nanoparticles. A series of supported gold, palladium, platinum and combinations of these metals have been investigated. In the presence of base the major product formed is lactate, often in excellent yields as, under these conditions the terminal hydroxyl group is oxidised. In the absence of base, more vigorous conditions are required to elicit high conversions; surprisingly, a major product from such reactions is a mono-oxidation product hydroxyacetone, along with lactate. © 2012 Springer Science+Business Media New York
Chapter 3 - Excavations at Tac-Cawla, Rabat, Gozo, 2014 (Temple places: Excavating cultural sustainability in prehistoric Malta)
No full textp.s. Vella Nicholas C. co-author appears on the print version but not the online version.In this chapter, we present the results of archaeological excavations at the prehistoric settlement known as Taċ-Ċawla, Rabat, Gozo (site code TCC14), undertaken by the FRAGSUS Project from 27 March to 17 July 2014. This exercise involved sampling intact archaeological deposits for dateable environmental and economic remains, and identifying and interpreting new features found at a significant settlement site. The site had potential to tackle the fundamental research questions posed by the FRAGSUS Project (§1.5) and expand knowledge of early domestic settlement on Malta. [Excerpt from Introduction]peer-reviewe
Competition Policy in Network Industries: An Introduction
No full textThe author discusses issues of the application of antitrust law and regulatory rules to network industries. In assessing the application of antitrust in network industries, we analyze a number of relevant features of network industries and the way in which antitrust law and regulatory rules can affect them. These relevant features include (among others) network effects, market structure, market share and profits inequality, choice of technical standards, relationship between the number of active firms and social benefits, existence of market power, leveraging of market power in complementary markets, and innovation races. The author finds that there are often significant differences on the effects of application of antitrust law in network and non-network industries.
Author(s): Ezra Brown and Nicholas Loehr Source
No full textJSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Why is PSL(2, 7) = GL(3, 2)? Mathematical Association of America Ezra Brown and Nicholas Loehr 1. INTRODUCTION. The groups of invertible matrices over finite fields are among the first groups we meet in a beginning course in modern algebra. Eventually, we find out about simple groups and that the unique simple group of order 168 has two representations as a group of matrices. And this is where we learn that the group of 2x2 unimodular matrices over a seven-element field, with / and -/ identified, is isomorphic to the group of invertible 3x3 matrices over a 2-element field. In short, it is a fact that PSL(2, 7) = GL(3, 2). Many of us are surprised by this fact: why should a group of 2 x 2 matrices with mod-7 integer entries be isomorphic to a group of 3 x 3 binary matrices? There are a number of proofs of this remarkable theorem. Dickson [1, p. 303] gives a proof based on his general theorem giving uniform sets of generators and relations for the family of groups SL(2, q), where q is any prime power. One checks that the relations appearing in Dickson's presentation of PSL(2, 7) are satisfied by certain generators of GL(3, 2), implying that these groups have the same presentations and are therefore isomorphic. Dummit and Foote [2, show that every simple group of order 168 is necessarily isomorphic to the automorphism group Aut(.F) of the Fano plane T. They then show that Aut(^) = GL(3, 2) and that PSL(2, 7) is a simple group of order 168; the isomorphism theorem follows. Rotman gives the result as an exercise [5, Exercise 9.26, p. 281]. A hint is to begin with a simple group G of order 168 and use the seven conjugates of a Sylow 2-subgroup P of G to construct a sevenpoint projective plane; the proof is similar to Dummit and Foote's proof. Jeurissen [4] proves the result by showing that both PSL(2, 7) and GL(3, 2) are subgroups of index 2 of the automorphism group of a Coxeter graph. Elkies The aim of this paper is to give a proof that PSL(2, 7) = GL(3, 2) that is elementary in the sense that it uses neither simplicity, nor projective geometry, nor block designs. We will not prove the fact that any two simple groups of order 168 are isomorphic, nor will we use this fact in our proof. What makes our proof work is that: (a) we can identify GL(3, 2) with the set of invertible F2-linear transformations on the finite field with eight elements; (b) 7 = 23 -1; (c) the nonzero squares mod 7 are precisely the powers of 2 mod 7; (d) squaring mod 2 is additive (the Freshman's Dream); and (e) the mapping k h+ -i/k mod 7 translates to a bit-switch mod 2 -which is linear. We begin by giving functional descriptions for both groups, determining their sizes
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