8,102 research outputs found
New ruthenium catalysts for asymmetric hydrogenation
No full textA review on catalytic asymmetric hydrogenation of C=O double bonds is presented in
the first chapter. Noyori’s pioneering research on ruthenium complexes containing both
phosphine and diamine ligands using
[i superscript]PrOH and
[t superscript]BuOK is described, this system gave
impressive highly chemeo-selectivity for C=O bonds and extremely high enantioselectivity
for a range of acetophenone derivatives. Numerous groups have been inspired by Noyori’s
catalyst of the type RuCl₂(chiraldiphosphine)(chiraldiamine), these systems often give
excellent results for acetophenone. However, these catalysts have limitations, they are found
to be either inactive or unselective for hydrogenation of tetralones, dialkylketones, bulky
ketones, some heterocyclic ketones and imines prove difficult using this system.
In this project, we are searching for a new catalyst for asymmetric hydrogenation of
ketones that solve the difficult challenges faced when using Noyori’s
[Ru(diphosphine)(diamine)Cl₂] catalysts system. Departing from Noyori’s type catalyst in the
second chapter is described our effort to synthesise new diamines derived from amino acids
and the synthesis of [Ru(diamine)(diphosphine)Cl₂] complexes. These catalysts are tested in
asymmetric hydrgenation of ketones. In the next two chapters the finding of a new tridentate
P^N^NH₂ type ligand is reported and the novel ruthenium complex containing the tridentate
ligand has been synthesised and characterised by X-ray crystallography and been found to be
active in the hydrogenation of a range of C=O and C=N double bonds, including the
enantioselective hydrogenation of normally unreactive bulky ketones with up to 93 % ee. The
last chapter explains the transfer hydrogenation activity for this new catalyst, involving a
novel method of transfer hydrogenation reaction under microwave irradiation
Chloride fluxes in lily pollen tubes: a critical reevaluation
No full textMicroelectrodes, made from a Cl?-selective liquid ion exchanger previously used to measure putative Cl- fluxes in Lilium longiflorum pollen tubes, were characterized. The electrodes were poorly selective, possessing only about 10-fold selectivity for Cl? over other anions tested. They had only 2.4-fold selectivity for Cl? over the anionic form of the H+ buffer, MES, indicating that the electrode can indirectly detect H+ gradients. Apparent anion influx was detected along the pollen tube shafts and at the grains while apparent anion efflux was detected near the tip of the tube. During oscillating growth, the peak of the oscillating apparent anion efflux at the tip occurred, on average, 7.9 sec after the peak of the growth oscillations. Consideration of the previously characterized H+ fluxes in lily pollen grains and tubes, as well as the poor anion selectivity of the Cl? electrodes, indicates that the putative Cl? fluxes are in fact changes in the anionic concentration of the buffer resulting from H+ gradients and not changes in Cl? concentration. The claim of a central role for Cl? in lily pollen tube growth is further undermined by the fact that these tubes grow at the same rate if the Cl? content of the growth medium is reduced to trace levels (?31 ?m), and that the grains have only small reserves of Cl?. These results lead to the conclusion that Cl? fluxes are not a significant component of pollen tube growth and Cl? itself is not required for growt
Corporate Governance and Reputation: A Disaster Story
No full textIt is often commented that it may take a company generations to acquire a solid corporate reputation and only seconds to lose it. One of the fastest ways to lose a corporate reputation is enduring a disaster in corporate governance. The scale and contagion of the recent global financial crisis has starkly confirmed this, however episodic crisis and frequent corporate governance failures have punctuated the development of the market system (Clarke 2007). There are many explanations for the recent sustained and intense interest in corporate governance including the growth of international capital markets, the scale of the multinationals, the increasing proportion of individual wealth held in securities with the development of vast investment institutions, and the dawning awareness that if these investments are to be secure there must be effective monitoring and higher standards of corporate governance
Transmembrane anion transport: investigating mechanism and selectivity
No full textIn the last decade, the development of synthetic anion transporters has attracted much attention. A variety of small molecules have been established to facilitate the transport of biologically relevant anions such as chloride, bicarbonate and sulfate across lipid bilayers. This interest has been piqued due to their potential as therapeutics for ‘channelopathies’ such as cystic fibrosis and in some cases their anion transport has been linked to anti-cancer activity in cells.This thesis explores a new series of chloride transporters which possessed high binding affinity for oxo-anions such as phosphate and bicarbonate. They were found to transport via an antiport mechanism, with a preference for Cl-/NO3- over Cl-/HCO3-. The series also exhibited some self-association characteristics, which appeared detrimental to their transport activity.The transmembrane transport of fluoride was also investigated using a series of strapped calix[4]pyrroles. The fluoride transport was monitored directly using ion selective electrode and NMR techniques. The length of the strap was found to modulate the fluoride over chloride selectivity, showing fluoride selectivity for the shortest strapped calix[4]pyrroles.Furthermore the fundamental transport mechanism of these calix[4]pyrroles was elucidated as electrogenic by extending the series and employing cationophore coupling techniques. The smallest strapped receptor showed unprecedented Cl- selectivity even in the presence of fatty acid. Additional studies showed the rest of the series’ halide and nitrate selectivity follows an anti-Hofmeister bias
Open access self-archiving: An author study
No full textThis, our second author international, cross-disciplinary study on open access had 1296 respondents. Its focus was on self-archiving. Almost half (49%) of the respondent population have self-archived at least one article during the last three years. Use of institutional repositories for this purpose has doubled and usage has increased by almost 60% for subject-based repositories. Self-archiving activity is greatest amongst those who publish the largest number of papers. There is still a substantial proportion of authors unaware of the possibility of providing open access to their work by self-archiving. Of the authors who have not yet self-archived any articles, 71% remain unaware of the option. With 49% of the author population having self-archived in some way, this means that 36% of the total author population (71% of the remaining 51%), has not yet been appraised of this way of providing open access. Authors have frequently expressed reluctance to self-archive because of the perceived time required and possible technical difficulties in carrying out this activity, yet findings here show that only 20% of authors found some degree of difficulty with the first act of depositing an article in a repository, and that this dropped to 9% for subsequent deposits. Another author worry is about infringing agreed copyright agreements with publishers, yet only 10% of authors currently know of the SHERPA/RoMEO list of publisher permissions policies with respect to self-archiving, where clear guidance as to what a publisher permits is provided. Where it is not known if permission is required, however, authors are not seeking it and are self-archiving without it. Communicating their results to peers remains the primary reason for scholars publishing their work; in other words,
researchers publish to have an impact on their field. The vast majority of authors (81%) would willingly comply with a mandate from their employer or research funder to deposit copies of their articles in an institutional or subject-based repository. A further 13% would comply reluctantly; 5% would not comply with such a mandate
Progress of international hydrogen production network for the thermochemical Cu–Cl cycle
No full textThis paper presents recent advances by an international team which is developing the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. Development of the Cu–Cl cycle has been pursued by several countries within the framework of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Due to its lower temperature requirements in comparison with other thermochemical cycles, the Cu–Cl cycle is particularly well matched with Canada's Generation IV reactor, SCWR (Super-Critical Water Reactor), as well as other heat sources such as solar energy or industrial waste heat. In this paper, recent developments of the Cu–Cl cycle are presented, specifically involving unit operation experiments, corrosion resistant materials and system integration.Atomic Energy of Canada LimitedOntario Research Excellence FundNatural Sciences and Engineering Research Council of CanadaUniversity Network of Excellence in Nuclear Engineering (UNENE)Canada Research Chairs progra
ŻYCIE UKRYTE W SŁOWIE. "BEKSIŃSCY. PORTRET PODWÓJNY" MAGDALENY GRZEBIAŁKOWSKIEJ W ŚWIETLE POSTSTRUKTURALIZMU
No full textLife Hidden in Words. Magdalena Grzebiałkowska\u27s "Beksińscy. Portret podwójny" and Poststructuralism
The article analyzes Magdalena Grzebiałkowska\u27s biographical "Beksińscy. Portret podwójny" which focuses on the lives of Zdzisław Beksiński and Tomasz Beksiński. The author looks at the construction of the biography and its relationship to poststructuralism, which allows for an appreciation of the literary features of the book. He points to how the specificity of the content, language, a mode of narration in Grzebiałkowska\u27s book make it a full-fledged literary work itself. As such the book departs from a typical biographical scheme. Juxtaposing the book with poststructural ideas leads to the reconsideration of the role of the author in the process of shaping of a biographical narrative
Clarke & Scully’s Drainage Cases, 1889-1903 (2 v)
No full textReports of the Decisions of the Referees Appointed for the Purpose of the Drainage Laws and of the Court of Appeal for Ontario : in Cases Where the Referees\u27 Decisions Have Been Appealed from, as Well as of Some Other Important Decisions of the Courts Relative to the Drainage Laws and Including The Municipal Drainage Act (R.S.O. 1897, chapter 226) and The Ditches and Watercourses Act (R.S.O. 1897, chapter 285), Annotated, with the Names of the Cases Bearing Upon Them, Reported in This Volume with a Table of the Names of the Cases Cited and a Digest of the Principal Matters / by Alfred Henry Clarke and Edmund I. Scully. Windsor, Ont : Echo Printing Co., 1898 ; Toronto : The Carswell Company, Limited, 1903. 2 v
Cited as: C & S (preferred) ; CL & ScD r Cas ; Clarke & Sc Dr Cas v 1 (1889-1898) – Windsor: Echo Printing Co., 1898 v 2 (1898-1903) – Toronto: The Carswell Company, Limited, 1903https://digitalcommons.osgoode.yorku.ca/lawreports/1003/thumbnail.jp
Systems, methods and devices for the capture and hydrogenation of carbon dioxide with thermochemical Cu—Cl and Mg—Cl—Na/K—CO2 cycles
No full textSystems, methods, and devices for producing hydrogen and capturing CO2 from emissions combine both H2 production and CO2 capture processes in forms of thermochemical cycles to produce useful products from captured CO2. The thermochemical cycles are copper-chlorine (Cu—Cl) and magnesium-chlorine-sodium/potassium cycles (Mg—Cl—Na/K—CO2). One system comprises a Cu—Cl cycle, a CO2 capture loop, and a hydrogenation cycle. Another system comprises an Mg—Cl—Na/K—CO2 cycle and a hydrogenation cycle. Devices for hydrogen production, CO2 capture, hydrogenation, and process and equipment integration include a two-stage fluidized/packed bed, hybrid two-stage spray-fluidized/packed bed reactor, a two-stage wet-mode absorber, a hybrid two-stage absorber, and a catalyst packed/fluidized bed reactor
Clarke & Scully’s Drainage Cases, 1889-1903 (2 v)
No full textReports of the Decisions of the Referees Appointed for the Purpose of the Drainage Laws and of the Court of Appeal for Ontario : in Cases Where the Referees\u27 Decisions Have Been Appealed from, as Well as of Some Other Important Decisions of the Courts Relative to the Drainage Laws and Including The Municipal Drainage Act (R.S.O. 1897, chapter 226) and The Ditches and Watercourses Act (R.S.O. 1897, chapter 285), Annotated, with the Names of the Cases Bearing Upon Them, Reported in This Volume with a Table of the Names of the Cases Cited and a Digest of the Principal Matters / by Alfred Henry Clarke and Edmund I. Scully. Windsor, Ont : Echo Printing Co., 1898 ; Toronto : The Carswell Company, Limited, 1903. 2 v
Cited as: C & S (preferred) ; CL & ScD r Cas ; Clarke & Sc Dr Cas v 1 (1889-1898) – Windsor: Echo Printing Co., 1898 v 2 (1898-1903) – Toronto: The Carswell Company, Limited, 1903https://digitalcommons.osgoode.yorku.ca/lawreports/1003/thumbnail.jp
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