2,972 research outputs found
Lydia S. Wierman letter to Thomas Earl
No full textLetter from Lydia S. Wierman to Thomas Earl of Philadelphia, care of George Forman. Wierman's letter has been truncated somewhat -- here, we have only pages 4 and 5 of what presumably is a longer letter. Weirman speaks eloquently and passionately about the life and work of her brother, abolitionist Benjamin Lundy. Page 4 of the letter opens in the midst of recounting a story by which someone crawls to safety in a wintry woods. The letter continues in a consideration of Lundy's tremendous life's work in abolitionism from Wierman's perspective. Benjamin Lundy (1789-1839) was a prominent Quaker abolitionist best known for his development of abolitionist periodicals. His Genius of Universal Emancipation was first published in 1821 from his home in Mt. Pleasant, Ohio, and enjoyed a wide circulation across the antebellum United States. In the 1820s, the young William Lloyd Garrison came to work for The Genius. Benjamin Lundy traveled widely seeking subscriptions to The Genius, giving talks a
Dinuclear niobium(III), tantalum(III) and tantalum(IV) complexes with thioether and selenoether ligands
No full textMagnesium reduction of MCl5 (M = Nb or Ta) in the presence of R2S (R = Me or nBu) affords the complexes [M2Cl4(R2S)2(μ-Cl)2(μ-R2S)]. The X-ray structures of those complexes where M = Nb or Ta, R = nBu2S, and of a new polymorph of [Ta2Cl4(Me2S)2(μ-Cl)2(μ-Me2S)], show that they have confacial bi-octahedral structures with M=M double bonds. The reactions of [Nb2Cl4(R2S)2(μ-Cl)2(μ-R2S)] with MeSCH2CH2SMe, MeSeCH2CH2SeMe or MeSeCH2CH2CH2SeMe produce the edge-linked dimers [Nb2Cl4(MeSCH2CH2SMe)2(μ-Cl)2] and [Nb2Cl4{MeSe(CH2)nSeMe}2(μ-Cl)2], all with M=M double bonds (M26+). The tantalum diselenoether complex, [Ta2Cl4(MeSeCH2CH2SeMe)2(μ-Cl)2], is similar. Two “dimer of dimers”, [{Nb2Cl4(μ-Cl)2(μ-Me2S)}2(μ-MeSeCH2CH2CH2SeMe)2] and [{Ta2Cl4(μ-Cl)2(μ-Me2S)}2(μ-nBuSeCH2CH2CH2SenBu)2], containing confacial bi-octahedra linked by diselenoether bridges, were obtained as minor by-products and were identified via their X-ray crystal structures. The xylyl-linked diselenoether, o-C6H4(CH2SeMe)2, gave a complex mixture of products, including [Ta2Cl4{o-C6H4(CH2SeMe)2}2(μ-Se)2]. The complexes were characterised by microanalysis, IR and UV–visible spectroscopy. X-ray crystal structures are reported for [Nb2Cl6(nBu2S)3], [Ta2Cl6(nBu2S)3], [Ta2Cl8(Me2S)2], [Ta2Cl6(Me2S)3], [Ta2Cl4{o-C6H4(CH2SeMe)2}2(Se)2], [{Ta2Cl6(Me2S)(nBuSeCH2CH2CH2SenBu)}2] and [Ta2Cl4(Me2S)4(S)2]
Synthesis of dendritic gadolinium complexes with enhanced relaxivities
No full textThis thesis deals with the synthesis of dendritic gadolinium complexes based on DOTA, with a view to obtaining enhanced relaxivities. Li addition to the inherently long electronic relaxation time and high paramagnetic moment of the gadolinium (III) ion, the speed of rotation of its complexes in solution is a decisive parameter in the determination of the relaxivity. This parameter is dependent on the molecular mass of the complex. Initially, the enantioselective synthesis of novel a-substituted analogues of DOTA was attempted but was not successful due to difficulties encountered in attaining the tetraalkylation of cyclen and the purification of the products obtained. Therefore, further studies were carried out based on the known [Gd(gDOTA)]" system. The synthesis of three medium M(_W) dendrons, each with a focal primary amino group was carried out. Their structures may be described as dendrimeric analogues of poly(ethylene glycol). Two of these structures were successfully coupled to the gadolinium (III) chelate, [Gd.gDOTA]. The acid-catalysed epimerisation of the statistical distribution of stereoisomers yielded solely the (RRRR)/(SSSS) isomeric pair. This system had previously been shown to undergo fast water exchange. The coupling and deprotection procedure yielded paramagnetic dendritic complexes with molecular weights of 2013 and 3535.Relaxivity measurements were carried out on these systems and the results showed significantly higher relaxivities of 18 and 21 mM(^-1) s(^-1) respectively, compared with a value of 7.8 mM(^-1) s(^-1) for the parent compound. Examination of NMRD profiles for the larger system showed a decrease in the rotational correlation time to 310 ps at 298 K, as expected. However, this was accompanied by an increase in the inner-sphere water exchange lifetime to 570 ns at 298 K. Therefore, although an improvement in relaxivity was obtained through a coupling to the slower rotation of the system in solution, this enhancement was limited by the accompanying decrease in the rate of water exchange. The best fitting procedure of the NMRD profiling procedure revealed the presence of 8 second-sphere water molecules at an average distance of 4Å. The second sphere contribution was shown to be the dominant contributor to the overall relaxivity. This accounted for >50% of the increased relaxivity
Public worship and practical theology in the work of Benjamin Keach (1640-1704)
No full textThe late seventeenth century was a critical and fruitful period
for the Particular Baptists of England. Severely persecuted following
the Restoration, toleration in 1689 brought its own perils.
Particular Baptists were fortunate in having several strong leaders,
especially the London trio of Hanserd Knollys, William Kiffin, and
Benjamin Keach. Such a small and severely persecuted group as the
Baptists could afford little time for academic pursuits, thus of
necessity most of their theology was practical in nature.
Benjamin Keach (1640-1704) was the most outstanding practical
theologian among the English Particular Baptists of the late
seventeenth century. This dissertation is a study of Keach, in
particular his writings on public worship and practical theology.
Although Keach was a prolific author, he has been almost completely
neglected by scholars.
After a biographical sketch of Keach, this study considers his
writings on public worship and practical theology. In the area of
worship, Keach made two outstanding contributions: First, he was the
most vocal apologist for Baptist views on Baptism of his period.
Secondly, and more importantly, his hymn writing and defense of hymn
singing broke new ground, not just for Baptists, but for English
Protestantism, in general. In addition to his contributions in these
areas, he also dealt with the laying on of hands and the sabbath day
worship controversy.
Keach's contributions to practical theology fall into two main
groups: his writings that concern religious education and those that
deal with polity. In addition to these, Keach's vigorous advocacy of
a high Calvinist soteriology are also considered under the rubric of
practical theology. Keach's most important (although not his most
positive) contribution in this area were his soteriological writings.
Although well within the bounds of orthodoxy, some of the tendencies
in Keach's soteriology were taken up by the following generation of
Baptist leaders and developed into a stultifying hyper-Calvinism that
handicapped Baptist evangelism and missions.
In the conclusion, Keach's contributions to a theory of practical
theology are considered
Like Shapes Moving in Another World: An Identification and Interpretation of Mythical Figures in C. S. Lewis’ Novel The Silver Chair
No full textAs a result of his conversion to Christianity, author C. S. Lewis felt compelled to formulate a unique definition of myth. From his perspective, myth is a means through which God communicates His truth to the non-Christian world. Myth recognizes the yearning for home all people experience yet cannot satisfy, but while it correctly diagnoses humanity’s symptoms, myth fails to treat the underlying disease responsible for them. The influence of non-Christian, specifically Greek, myth can be felt most strongly in The Silver Chair, the sixth installment of Lewis’ series The Chronicles of Narnia. Through the allusions this essay explores, in addition to many others, The Silver Chair presents a mythical world both reminiscent of and distinct from its source material. Lewis’ alterations to the original myths reflect his belief in a world to come. They also shine a new light on all the myths that are referenced within The Silver Chair. In this new light, the faint hints of the gospel glimmer, and these glimmers should inspire mythologists, especially those who believe in Jesus Christ, to reexamine their favorite stories with an aim to identify the Christian themes that move within them
Functional fluorocarbons via free radical additions to hexafluoropropene
No full textThe effect of substituents on the carbon-hydrogen bond reactivity in free radical additions to hexaf1uoropropene has been investegated. Ethers, amines, amides, isocyanates and silanes all give Free radical adducts. The order of reactivity has been compiled. The reactivity of cyclic ethers, amines and amides is discussed in terms of the stereoelectronic effect. The reactivity of tetrahydrofuran and N-methylpyrrolidine towards hexaf1uoropropene under uninitiated conditions has also been demonstrated. The ease of hydrogen abstraction from the substrates was estimated using a method based on the thermal decomposition of ditertiarybutylperoxide. A correlation between the ease of hydrogen abstraction and free radical reactivity is demonstrated, although the reactivity of aldehydes is not simply explained. The adducts of ethers and amines can be dehydrofluorinated to give a variety of alkenes. Further reactions of aldehyde and isocyanate adducts has given good synthetic routes to other functionally substituted fluorocarbons. The amide adducts are also a useful source o-f fluorinated amines which cannot be obtained directly. An amine 1:1 adduct has been fully fluorinated over cobalt trifluoride at 440 C in good yield, although higher adducts give lower yields. Remarkably high yields of perfluorinated alkanes are produced by successive reaction with sulphur tetrafluoride and cobalt trifluoride
Front Matter, Table of Contents, Preface, List of Authors
No full textFront Matter, Table of Contents, Preface, List of Author
Stratospheric geoengineering with black carbon aerosols
No full textI use a general circulation model of Earth's climate to simulate stratospheric geoengineering with black carbon aerosols, varying the altitude of injection, initial particle size, and whether the deposited black carbon modifies ground albedo. 1 Tg of black carbon aerosols injected into the stratosphere each year will cause significant enough surface cooling to negate anthropogenic warming if the aerosols are small (r=0.03 μm) or if the aerosols are injected into the middle stratosphere, although using small aerosols causes large regional cooling effects that would be catastrophic to agriculture. The aerosols cause significant stratospheric heating, resulting in stratospheric ozone destruction and circulation changes, most notably an increase in the Northern Hemisphere polar jet, which forms an Arctic ozone hole and forces a positive mode of the Arctic Oscillation. The hydrologic cycle is perturbed, specifically the summer monsoon system of India, Africa, and East Asia, resulting in monsoon precipitation collapse. Global primary productivity is decreased by 35.5% for the small particle case. Surface cooling causes some sea ice regrowth, but not at statistically significant levels. All of these climate impacts are exacerbated for small particle geoengineering, with high altitude geoengineering with the default particle size (r=0.08 μm) causing a reasonable amount of cooling, and large particle (r=0.15 μm) geoengineering or particle injection into the lower stratosphere causing few of these effects. The modification of ground albedo by the soot particles slightly perturbs the radiative budget but does not cause any distinguishable climate effects. The cheapest means we investigated for placing 1 Tg of black carbon aerosols into the stratosphere by diesel fuel combustion would cost 541 billion annual, or 2.0% and 0.8% of GDP, respectively. The additional carbon dioxide released from combusting diesel to produce these aerosols is about 1% of current emissions, but the additional NOx would be 17% of current sources and could further reduce the total ozone column by up to 10%. Geoengineering with carbon black, if technically feasible, would be much cheaper, costing approximately 1.3 billion annually, with few troublesome emissions factors.Ph.D.Includes bibliographical referencesIncludes vitaby Benjamin S. Kravit
The Synthesis of homochiral ligandsand their application to asymmetric fluorinating reagents
No full textThis thesis is concerned with the synthesis of homochiral ligands and their application to asymmetric fluorinations. Initial work focused on the synthesis of homochiral pyridine based ligands and the determination of their optical purity. 2-Acetylpyridine was reduced using bakers' yeast in the presence of an enzyme inhibitor to give a homochiral pyridyl alcohol. A double asymmetric reduction of 2,6-diacetylpyridine was also achieved using bakers' yeast and the resulting diol was also found to be homochiral. Derivatives of the above pyridyl alcohols were then reacted with 10% F2/N2 in the presence of a suitable counterion to form N-fluoropyridinium salts. These reagents were then used to fluorinate a range of silyl ketene acetals and metal enolates to assess their ability as asymmetric electrophilic fluorinating reagents. Although the reagents achieved fluorination, they were found to be poor asymmetric fluorinating reagents. A new synthetic route into the pyrrolidine based amine (2S)-(diphenyl)methylpyrrolidine was developed and its use in a number of asymmetric transformations was investigated. Both DAST and Ishikawa's reagent have proved successful in achieving the replacement of alcohol hydroxyl groups by fluorine. Development of a nucleophilic asymmetric fluorinating reagent based on DAST and Ishikawa's reagent was attempted using (2S)-(diphenyl)methylpyrrolidine as the precursor amine. The homochiral derivatives of DAST and Ishikawa's reagent which were developed, only achieved limited success as fluorinating reagents and the fluorinated products were found to be racemic.(2S)-(Diphenyl)methylpyrrolidine was also found to act as a chiral solvating reagent with certain carboxylic acids and alcohols, these showing chemical non-equivalence by NMK Two (2S)-(diphenyl)methylpyrrolidine units were also coupled together by a two and three carbon bridge forming two novel diamines. Initial studies on the ability of these amines to act as asymmetric catalysts in dihydroxylation reactions using osmium tetroxide and asymmetric addition reactions of Grignard reagents to aldehydes are also described
More than just victims: the truth about human trafficking
No full textBenjamin S Buckland argues that the language used to debate human trafficking can cloud the issue itself. Exploitation is only one side of the story. Deep-rooted socioeconomic and political reasons explain why some people fall into illegal or forced migration channels, and tackling these fundamentals requires a new language to acknowledge the agency and ambition of trafficked persons. Copyright (c) 2008 The Author. Journal compilation (c) 2008 ippr.
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