New routes to fluorocarbon-containing phosphines

Routes to sterically demanding organofluorine-containing phosphines are described, and the stereoelectronic properties and chemistry of the resulting new ligands investigated. The synthesis of Cy2P(CF=CF2), 3, has been accomplished. The nucleophilic substitution of Ph2P(CF=CF2) with tBuLi produces the (Z)-isomer, Ph2P(Z-CF=CF(tBu)), 5-(Z), predominantly, which has been shown to be less electron-withdrawing than Ph2P(CF=CF2), and similar in size to 3. The bis-trifluoropropynyl substituted phosphine PhP(tfp)2, 7, has been prepared, and its reaction with tBuLi investigated. This results in the formation of three previously unknown species, the gem¬-difluorocyclopropenyl-containing compound, PhtBuP(dfcp), 8, (Z)-Ph2P(CH=C(t¬Bu)CF3), 9, and PhtBuP(tfp), 10. The nucleophilic substitution occurs preferentially at the phosphorus centre, as shown by the reaction with one equivalent of tBuLi at -60°C, where compounds 9 and 10 are formed. A new route to perfluoroalkyl-containing phosphines has been discovered. The addition of a perfluoroalkyl iodide to Ph2PSiMe3 results in the formation of six new phosphines, and has been shown to be extendable to partially fluorinated systems. The route can also be applied to iPr2PSiMe3, and to the chiral phosphine PhMePSiMe3. Three examples, Ph2PRf (Rf = CF(CF3)2, 15, (sC4F¬9), 18, (cyc-C6F11), 19), have been produced on a preparative scale. The reaction of the bis-trimethylsilyl phenyl phosphine with (CF3)2CFI has been investigated, though it does not result in the production of the bis-perfluoroalkyl-substituted phosphine, instead the previously unknown P-chiral compound, PhP(H)CF(CF3)2, 27 is formed. Mechanistic studies have indicated that Ph2P-PPh2 is the intermediate, and that there is no evidence of a radical mechanism. There is no reaction between Me2(S)P-P(S)Me2 and (CF3)2CFI, though there is when Me2P-P(S)Me2 is used, suggesting that the lone pair of the intermediate diphosphine is necessary for the reaction to proceed. This has resulted in the formation of the new compound, Me2PCF(CF3)2, 28. The chemistry of the perfluoroalkyl-containing phosphines has been investigated; they do not quaternise, but are oxidatively sensitive. The phosphorus(V) selenides of 15, 18, and 19 have been prepared, and based on their 1JPSe coupling constants, the perfluoroalkyl-groups impart a greater electron-withdrawing effect than perfluorovinyl, trifluoropropynyl, or alkoxy fragments. The oxidation of 15 and 18 with XeF2 has also been accomplished, and shown to yield the corresponding F2PPh2Rf compounds. The molybdenum(0) pentacarbonyl complexes of 3, 7, and 15 have been synthesised and perfluoroalkyl-groups have again been shown to be more electron-withdrawing than perfluorovinyl and trifluoropropynyl groups by comparison of v(CO) values. The gold(I) chloride complexes of Ph2PCF3, 15, and 18 and the platinum(II) dichloride complexes of 3 and 15 have been prepared, and the size of these ligands has been estimated from the crystal structures. Compound 18 has been shown to be the largest of these compounds, with a cone angle of 187°.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Estimation of relative abundance of recreationally important finfish in the Virginia portion of the Chesapeake Bay : annual progress report, U.S. Fish and Wildlife Service Sportfish Restoration Project F104R2, July 1992 - June 1993, Revised edition 1994

This document is a revised edition of an original manuscript presented to the U.S. Fish and Wildlife Service and the Virginia Marine Resources Commission in partial fulfillment of contract obligations (Sportfish Restoration Project F104R2)

Carbon induced extreme ultraviolet (EUV) reflectance loss characterized using visible-light ellipsometry

Carbon deposition on extreme ultraviolet (EUV) optics was observed due to photon-induced dissociation of hydrocarbons in a EUV lithography environment. The reflectance loss of the multilayer mirror is determined by the carbon layer thickness and density. To study the influence of various forms of carbon, EUV-induced carbon, hot filament and e-beam evaporated carbon were deposited on EUV multilayer mirrors. Spectroscopic ellipsometry was used to determine the carbon layer thickness and the optical constants ranging from ultraviolet to near infrared. The carbon density (and thus reflectance loss) was determined from the optical constants using both Bruggeman's effective medium approximation and the Clausius–Mosotti equation. Both approaches result in a similar EUV reflectance loss, with an accuracy of about 4%. The application of this process to ultrathin carbon films is further discussed

Effects of Reapeated Doses of Caffeine on Performance and Alertness: New Data and Secondary Analyses

Rationale The effects of caffeine on mood and performance are well established. Some authors suggest that caffeine merely reverses effects of caffeine withdrawal rather than having direct behavioural effects. It has also been suggested that withdrawal may be removed by a first dose of caffeine and further doses have little subsequent effect. These issues were examined here. Objectives The present study aimed to determine whether caffeine withdrawal influenced mood and performance by comparing regular consumers who had been withdrawn from caffeine overnight with non-consumers. Following this repeated caffeine doses were administered to test the claim that repeated dosing has no extra effect on mood or performance. Secondary analyses of a data collected by Christopher et al. (2003) were also carried out to examine some alternative explanations of their results which showed effects of caffeine after a day of normal caffeine consumption. Methods One hundred and twenty volunteers participated in the study. Regular caffeine consumption was assessed by questionnaire and this showed that thirty six of the sample did not regularly consume caffeinated beve rages. Volunteers were instructed to abstain from caffeine overnight and then completed a baseline session measuring mood and a range of cognitive functions at 08.00 the next day. Following this volunteers were given 0, or 1mg/kg caffeine in a milkshake, glucose solution or water (at 09:00), followed by a second 0 or 1mg/kg caffeine dose (at 09:40) and the test battery repeated at 10:00. Results The baseline data showed no effect of overnight caffeine withdrawal on mood or performance. In contrast, caffeine challenge improved vigilance performance and prevented decreases in alertness induced by completion of the task battery. The magnitude of these effects increased as a function of the number of doses of caffeine given. Secondary analyses of data from Christopher et al. (2003) also confirmed that effects of caffeine did not depend on length of withdrawal. Conclusions The present findings show no effect of overnight caffeine withdrawal on mood and performance. Caffeine challenge did have the predicted effect on alertness and vigilance, with the size of the effects increasing with caffeine dose. These findings suggest that the effects of caffeine are not due to reversal of effects of withdrawal, a view confirmed by secondary analyses of data collected after a day of normal caffe ine consumption

The re-birth of the "beat": A hyperlocal online newsgathering model

This is an Author's Accepted Manuscript of an article published in Journalism Practice, 6(5-6), 754 - 765, 2012, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/17512786.2012.667279.Scholars have long lamented the death of the 'beat' in news journalism. Today's journalists generate more copy than they used to, a deluge of PR releases often keeping them in the office, and away from their communities. Consolidation in industry has dislodged some journalists from their local sources. Yet hyperlocal online activity is thriving if journalists have the time and inclination to engage with it. This paper proposes an exploratory, normative schema intended to help local journalists systematically map and monitor their own hyperlocal online communities and contacts, with the aim of re-establishing local news beats online as networks. This model is, in part, technologically-independent. It encompasses proactive and reactive news-gathering and forward planning approaches. A schema is proposed, developed upon suggested news-gathering frameworks from the literature. These experiences were distilled into an iterative, replicable schema for local journalism. This model was then used to map out two real-world 'beats' for local news-gathering. Journalists working within these local beats were invited to trial the models created. It is hoped that this research will empower journalists by improving their information auditing, and could help re-define journalists' relationship with their online audiences

Intravital FRAP imaging using an E-cadherin-GFP mouse reveals disease- and drug-dependent dynamic regulation of cell-cell junctions in live tissue

E-cadherin-mediated cell-cell junctions play a prominent role in maintaining the epithelial architecture. The disruption or deregulation of these adhesions in cancer can lead to the collapse of tumor epithelia that precedes invasion and subsequent metastasis. Here we generated an E-cadherin-GFP mouse that enables intravital photobleaching and quantification of E-cadherin mobility in live tissue without affecting normal biology. We demonstrate the broad applications of this mouse by examining E-cadherin regulation in multiple tissues, including mammary, brain, liver, and kidney tissue, while specifically monitoring E-cadherin mobility during disease progression in the pancreas. We assess E-cadherin stability in native pancreatic tissue upon genetic manipulation involving Kras and p53 or in response to anti-invasive drug treatment and gain insights into the dynamic remodeling of E-cadherin during in situ cancer progression. FRAP in the E-cadherin-GFP mouse, therefore, promises to be a valuable tool to fundamentally expand our understanding of E-cadherin-mediated events in native microenvironments

The RESOLVE Trial for people with chronic low back pain: Statistical analysis plan

Background: Statistical analysis plans describe the planned data management and analysis for clinical trials. This supports transparent reporting and interpretation of clinical trial results. This paper reports the statistical analysis plan for the RESOLVE clinical trial. The RESOLVE trial assigned participants with chronic low back pain to graded sensory-motor precision training or sham-control. Results: We report the planned data management and analysis for the primary and secondary outcomes. The primary outcome is pain intensity at 18-weeks post randomization. We will use mixed-effects models to analyze the primary and secondary outcomes by intention-to-treat. We will report adverse effects in full. We also describe analyses if there is non-adherence to the interventions, data management procedures, and our planned reporting of results. Conclusion: This statistical analysis plan will minimize the potential for bias in the analysis and reporting of results from the RESOLVE trial. Trial registration: ACTRN12615000610538 (https://www.anzctr.org.au/Trial/Registration/ TrialReview.aspx?id=368619). © 2020 Associac¸ao˜ Brasileira de Pesquisa e Pos-Graduac ´ ¸ao˜ em Fisioterapia. Published by Elsevier Editora Ltda. All rights reserved

‘Caution! The Bread is Poisoned’: The Hong Kong Mass Poisoning of January 1857

This article examines the Hong Kong mass poisoning of 15 January 1857, in which bread from a Chinese bakery that supplied the colonial community was adulterated with arsenic. Even though there is a wealth of printed and manuscript documentation available many vital aspects of the poisoning remain unclear. What kind of incident was it: an act of terrorism and attempted mass murder, a war crime, a criminal conspiracy, an act of commercial sabotage, an accident or even an imagined or imaginary event? Throughout, our focus remains firmly fixed on the central act of the poisoning itself and on what it reveals about the precarious nature of early colonial Hong Kong. Interpretations have swarmed over the available ‘facts'. Equally ironic is what happened to the afterlife of how the event was understood. This article seeks to rescue the Hong Kong poisoning from being a freakish and isolated footnote of only local interest. Accepting this historical verdict would be a mistake as it is of significance not only at a local level, but geopolitically in Britain and across the empire