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Radicals
Kinds of Radicals Terms modified by Radicals Selected AbstractsReduction of ciclosporin and tacrolimus nephrotoxicity by plant polyphenolsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2006Zhi Zhong The immunosuppressants ciclosporin (cyclosporin A, CsA) and tacrolimus can cause severe nephrotoxicity. Since CsA increases free radical formation, this study investigated whether an extract from Camellia sinensis, which contains several polyphenolic free radical scavengers, could prevent nephrotoxicity caused by CsA and tacrolimus. Rats were fed powdered diet containing polyphenolic extract (0-0.1%) starting 3 days before CsA or tacrolimus. Free radicals were trapped with ,-(4-pyridyl-1-oxide)- N - tert -butylnitrone (POBN) and measured using an electron spin resonance spectrometer. Both CsA and tacrolimus decreased glomerular filtration rates (GFR) and caused tubular atrophy, vacuolization and calcification and arteriolar hyalinosis, effects that were blunted by treatment with dietary polyphenols. Moreover, CsA and tacrolimus increased POBN/radical adducts in urine nearly 3.5 fold. Hydroxyl radicals attack dimethyl sulfoxide (DMSO) to produce a methyl radical fragment. Administration of CsA or tacrolimus with 12C-DMSO produced a 6-line spectrum, while CsA or tacrolimus given with 13C-DMSO produced a 12-line ESR spectrum, confirming formation of hydroxyl radicals. 4-Hydroxynonenal (4-HNE), a product of lipid peroxidation, accumulated in proximal and distal tubules after CsA or tacrolimus treatment. ESR changes and 4-HNE formation were largely blocked by polyphenols. Taken together, these results demonstrate that both CsA and tacrolimus stimulate free radical production in the kidney, most likely in tubular cells, and that polyphenols minimize nephrotoxicity by scavenging free radicals. [source] ETHANOL-INDUCED SUPEROXIDE RADICALS IN FETAL CORTICAL NEURONS: CELLULAR ROS NETWORKALCOHOLISM, Issue 2008Amina E Jamali Alcohol exposure to the developing brain compromises both neurons and glial functions. While neurons are considered the primary targets, microglia may play a neurotoxic role in this process. Previous studies demonstrated that neuron death is due to oxidative stress and mitochondrially mediated (Intrinsic). These studies showed a rapid increase (within minutes) in reactive oxygen species (ROS). Due to the diffusive nature of ethanol and multiple sources of free radicals, we sought to determine the primary source of superoxide targeted by ethanol. Confocal studies of neurons suggest that the superoxide radicals may originate from the mitochondria. Using whole neurons in a luminol-based chemiluminescence assay (Diogenes) we detected superoxide radicals in the extracellular mileu. We observed a two-three fold transient increase in the steady state generation of superoxide radicals between 20 minutes to one hour of ethanol exposure (4mg/ml). However, the presence of Rotenone (mitochondrial complex I inhibitor) and DPI (an inhibitor of all flavinoids) blocked the release of these superoxide radicals. Interestingly, cortical microglia treated identically with ethanol, showed a greater than five fold increase in superoxide generation with a maximum at one hour. Moreover, since ethanol is known to induce hydrogen peroxide generation, it was used as a mimetic. Hydrogen peroxide also induced the production of superoxide different time kinetics. Thus, together these data demonstrate that ethanol induces the steady state production of superoxide radicals in the extracellular mileu in a mitochondrial dependent manner. Since NOX2 an NADPH oxidase is expressed in neurons, it is a potential candidate for the secondary sites of superoxide generation. The ROS network between mitochondria and the plasma membrane highlights new therapeutical targets to counter ethanol toxicity. [source] Dual Supermesityl Stabilization: A Room-Temperature-Stable 1,2,4-Triphosphole Radical, Sigmatropic Hydrogen Rearrangements, and Tetraphospholide Anion,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2008Alex S. Ionkin Abstract Cesium 3,5-bis(2,4,6-tri- tert -butylphenyl)-1,2,4-triphospholide (12) and cesium 5-(2,4,6-tri- tert -butylphenyl)tetraphospholide (13) were synthesized and isolated with flat five-membered rings, which are an indication of the aromaticity in these anions. Compound 13 is the first example of a stable tetraphospholide anion, which is structurally characterized. Kinetic stabilization of the 1,2,4-triphospholide system by two supermesityl groups resulted in the detection of the room-temperature-stable radical 17 and the observation of a series of successive sigmatropic hydrogen shifts in the first stable 1H -1,2,4-triphosphole 14 with a P,H bond.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] C-Glycosidations of a 2-Ketohexosyl Bromide with Electrophilic, Radical, and Nucleophilic Anomeric CarbonsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2003Frieder W. Lichtenthaler Abstract The susceptibility of acylated 2-ketohexosyl halides to C-homologation is demonstrated with the easily accessible tri- O -benzoyl-,- D - arabino -hexos-ulosyl bromide 1 as the model compound. C-Glycosidation with an electrophilic anomeric carbon requires prior carbonyl protection, to avoid carbonyl addition by the C-nucleophile, for example, as the cyanohydrin. Silver triflate-promoted reaction with the silylenol ether of acetophenone then efficiently yields the ,-phenacyl product. With thermal (AIBN) or photochemical induction, 1 smoothly generates an anomeric radical , comparatively electrophilic, due to its capto-dative substitution , which exclusively traps hydrogen in the presence of tributyltin and electron-deficient alkenes. With allyltributylstannanes, however, it reacts with high stereoselectivity to afford ,- C -allyl glycosiduloses. The ,-bromoketone functionality in ulosyl bromide 1 is susceptible to Reformatsky conditions: treatment with zinc-copper couple readily generates the 1,2-enolate, a most simple anomeric nucleophile, which effectively adds to aldehydes to give ,- C -hydroxyalkyl glycosiduloses or ,- C -disaccharides (with sugar aldehydes) with a high degree of double stereoselection. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Generation, Spectroscopic Characterization by EPR, and Decay of a Pyranine-Derived RadicalHELVETICA CHIMICA ACTA, Issue 10 2007Carolina Aliaga Abstract The pyraninoxyl radical is readily formed from the MnO2 -promoted oxidation of pyranine. The free radical can be formed in high concentrations (mM), and presents a characteristic EPR spectrum that indicates a high spin-density delocalization. It is relatively stable under nitrogen (half-life ca. 50,min) but readily decays in presence of O2. In spite of its high stability, the radical readily reacts with antioxidants (phenols and ascorbic acid) with a partial recovery of the parent pyranine. High concentrations of the pyraninoxyl radical (ca. 9,,M) are present when pyranine is exposed to a free radical source (10,mM 2,2,-azobis[2-amidinopropane], 37°). The fact that these radicals readily react with antioxidants (ascorbic acid and caffeic acid) supports the proposal that protection by antioxidants of peroxyl radical-promoted pyranine bleaching is mainly due to the occurrence of a repair mechanism. [source] Bile duct proliferation in Jag1/fringe heterozygous mice identifies candidate modifiers of the alagille syndrome hepatic phenotype,HEPATOLOGY, Issue 6 2008Matthew J. Ryan Alagille syndrome (AGS) is a heterogeneous developmental disorder associated with bile duct paucity and various organ anomalies. The syndrome is caused by mutations in JAG1, which encodes a ligand in the Notch signaling pathway, in the majority of cases and mutations in the NOTCH2 receptor gene in less than 1% of patients. Although a wide array of JAG1 mutations have been identified in the AGS population, these mutational variants have not accounted for the wide phenotypic variability observed in patients with this syndrome. The Fringe genes encode glycosyltransferases, which modify Notch and alter ligand-receptor affinity. In this study, we analyzed double heterozygous mouse models to examine the Fringe genes as potential modifiers of the Notch-mediated hepatic phenotype observed in AGS. We generated mice that were haploinsufficient for both Jag1 and one of three paralogous Fringe genes: Lunatic (Lfng), Radical (Rfng), and Manic (Mfng). Adult Jag1+/,Lfng+/, and Jag1+/,Rfng+/, mouse livers exhibited widespread bile duct proliferation beginning at 5 weeks of age and persisting up to 1 year. The Jag1+/,Mfng+/, livers showed a subtle, yet significant increase in bile duct numbers and bile duct to portal tract ratios. These abnormalities were not observed in the newborn period. Despite the portal tract expansion by bile ducts, fibrosis was not increased and epithelial to mesenchymal transition was not shown in the affected portal tracts. Conclusion: Mice heterozygous for mutations in Jag1 and the Fringe genes display striking bile duct proliferation, which is not apparent at birth. These findings suggest that the Fringe genes may regulate postnatal bile duct growth and remodeling, and serve as candidate modifiers of the hepatic phenotype in AGS. (HEPATOLOGY 2008;48:1989,1997.) [source] Disruptive information system innovation: the case of internet computingINFORMATION SYSTEMS JOURNAL, Issue 4 2003Kalle Lyytinen Abstract., Information system (IS) innovation can be defined as a novel organizational application of digital computer and information communication technologies (ICT). This paper discusses how modalities of applying ICT technologies in their form and scope exhibit radical breaks, which are introduced herein as ,disruptive IS innovations'. This notion of disruptive IS innovation is developed by drawing upon and extending Swanson's (1994) theory of IS innovation as well as the concept of radical innovation. Disruptive innovations strongly influence the future trajectory of the adoption and use of ICT in organizational contexts and make the trajectory deviate from its expected course. In doing so, these disruptive innovations distinctly define what an IS is and how it is deployed in order to address current and future organizational and managerial prerogatives. Such changes are triggered breakthroughs in the capability of ICT that lead to the revision and expansion of associated cognitive models (frames) of computing. Disruptive IS innovations are those that lead to changes in the application of ICT that are both pervasive and radical. The pervasive nature implies that innovative activity spans all innovation subsets of the quad-core model of IS innovation introduced herein. Innovation types include: IS use and development processes; application architecture and capability; and base technologies. Radical in nature, disruptive is innovations depart in significant ways from existing alternatives and lead to deviation from expected use and diffusion trajectory. This paper demonstrates the importance of a concept of disruptive IS innovation by investigating how changes triggered by internet computing (Lyytinen et al., 1998) meet the conditions of a disruptive IS innovation defined herein. The analysis also affirms both the pervasive and radical nature of internet computing and explains how internet computing has fundamentally transformed the application portfolio, development practices and IS services over time. The analysis demonstrates that, with the concept of disruptive IS innovation, we can fruitfully analyse ,long' waves of ICT evolution , an issue that has largely been overlooked in the IS community. On a theoretical plane, the paper advocates the view that we need to look beyond linear, unidirectional, and atomistic concepts of the diffusion of IS innovations where innovative activity takes places in a linear fashion by oscillating between small technological innovations and small organizational innovations. In contrast, IS innovation can exhibit fundamental discontinuity; we need to theoretically grasp such disruptive moments. The recent influx of innovation, spurred by internet-based technology, offers one such moment. [source] Synthesis, Structure, and Physical Properties of a New Organic Conductor Based on a ,-Extended Donor Containing a Stable 2,2,5,5-tetramethyl-1-pyrrolidinyloxy Radical,ADVANCED MATERIALS, Issue 19 2004H. Fujiwara A stable-organic-radical-functionalized tetrathiapentalene organic conductor has been synthesized and studied using X-ray crystallography of very small single crystals. The crystal structure reveals alternating conducting and insulating layers (see Figure). [source] Radical and cationic polymerizations of 3-ethyl-3-methacryloyloxymethyloxetaneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2001Tsuneyuki Sato Abstract 3-Ethyl-3-methacryloyloxymethyloxetane (EMO) was easily polymerized by dimethyl 2,2,-azobisisobutyrate (MAIB) as the radical initiator through the opening of the vinyl group. The initial polymerization rate (Rp) at 50 °C in benzene was given by Rp = k[MAIB]0.55 [EMO]1.2. The overall activation energy of the polymerization was estimated to be 87 kJ/mol. The number-average molecular weight (M,n) of the resulting poly(EMO)s was in the range of 1,3.3 × 105. The polymerization system was found to involve electron spin resonance (ESR) observable propagating poly(EMO) radicals under practical polymerization conditions. ESR-determined rate constants of propagation (kp) and termination (kt) at 60 °C are 120 and 2.41 × 105 L/mol s, respectively,much lower than those of the usual methacrylate esters such as methyl methacrylate and glycidyl methacrylate. The radical copolymerization of EMO (M1) with styrene (M2) at 60 °C gave the following copolymerization parameters: r1 = 0.53, r2 = 0.43, Q1 = 0.87, and e1 = +0.42. EMO was also observed to be polymerized by BF3OEt2 as the cationic initiator through the opening of the oxetane ring. The M,n of the resulting polymer was in the range of 650,3100. The cationic polymerization of radically formed poly(EMO) provided a crosslinked polymer showing distinguishably different thermal behaviors from those of the radical and cationic poly(EMO)s. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1269,1279, 2001 [source] Teaching & Learning Guide for: Victorian Life WritingLITERATURE COMPASS (ELECTRONIC), Issue 5 2007Valerie Sanders Author's Introduction The Victorian period was one of the great ages for life-writing. Though traditionally renowned for its monumental ,lives and letters', mainly of great men, this was also a time of self-conscious anxiety about the genre. Critics and practitioners alike were unsure who should be writing autobiography, and whether its inherent assertiveness ruled out all but public men as appropriate subjects. It was also a period of experimentation in the different genres of life-writing , whether autobiography, journals, letters, autobiographical novels, and narratives of lives combined with extracts from correspondence and diaries. Victorian life-writing therefore provides rich and complex insights into the relationship between narrative, identity, and the definition of the self. Recent advances in criticism have highlighted the more radical and non-canonical aspects of life-writing. Already a latecomer to the literary-critical tradition (life-writing was for a long time the ,poor relation' of critical theory), auto/biography stresses the hidden and silent as much as the mainstream and vocal. For that reason, study of Victorian life-writing appeals to those with an interest in gender issues, postcolonialism, ethnicity, working-class culture, the history of religion, and family and childhood studies , to name but a few of the fields with which the genre has a natural connection. Author Recommends A good place to start is the two canonical texts for Victorian life-writing: George P. Landow's edited collection, Approaches to Victorian Autobiography (Athens, OH: Ohio University Press, 1979) and Avrom Fleishman's Figures of Autobiography: The Language of Self-Writing in Victorian and Modern England (Berkeley and Los Angeles, CA: University of California Press, 1983). These two re-ignited interest in Victorian life-writing and in effect opened the debate about extending the canon, though both focus on the firmly canonical Ruskin and Newman, among others. By contrast, David Amigoni's recently edited collection of essays, Life-Writing and Victorian Culture (Aldershot: Ashgate 2006) shows how far the canon has exploded and expanded: it begins with a useful overview of the relationship between lives, life-writing, and literary genres, while subsequent chapters by different authors focus on a particular individual or family and their cultural interaction with the tensions of life-writing. As this volume is fairly male-dominated, readers with an interest in women's life-writing might prefer to start with Linda Peterson's chapter, ,Women Writers and Self-Writing' in Women and Literature in Britain 1800,1900, ed. Joanne Shattock (Cambridge: Cambridge University Press, 2001), 209,230. This examines the shift from the eighteenth-century tradition of the chroniques scandaleuses to the professional artist's life, domestic memoir, and spiritual autobiography. Mary Jean Corbett's Representing Femininity: Middle-Class Subjectivity in Victorian and Edwardian Women's Autobiographies (New York, NY: Oxford University Press, 1992) begins with material on Wordsworth and Carlyle, but ,aims to contest the boundaries of genre, gender, and the autobiographical tradition by piecing together a partial history of middle-class women's subjectivities in the nineteenth and early twentieth centuries' (3). Corbett is particularly interested in the life-writing of actresses and suffragettes as well as Martineau and Oliphant, the first two women autobiographers to be welcomed into the canon in the 1980s and 90s. Laura Marcus's Auto/biographical Discourses, Theory, Criticism, Practice (Manchester and New York, NY: Manchester University Press, 1994) revises and updates the theoretical approaches to the study of life-writing, stressing both the genre's hybrid qualities, and its inherent instability: in her view, it ,comes into being as a category to be questioned' (37). Another of her fruitful suggestions is that autobiography functions as a ,site of struggle' (9), an idea that can be applied to aesthetic or ideological issues. Her book is divided between specific textual examples (such as the debate about autobiography in Victorian periodicals), and an overview of developments in critical approaches to life-writing. Her second chapter includes material on Leslie Stephen, who is also the first subject of Trev Lynn Broughton's Men of Letters, Writing Lives: Masculinity and Literary Auto/biography in the Late Victorian Period (London: Routledge, 1999) , her other being Froude's controversial Life of Carlyle. With the advent of gender studies and masculinities, there is now a return to male forms of life-writing, of which Martin A. Danahay's A Community of One: Masculine Autobiography and Autonomy in Nineteenth-Century Britain (Albany, NY: State University of New York Press, 1993) is a good example. Danahay argues that nineteenth-century male autobiographers present themselves as ,autonomous individuals' free of the constraints of social and familial contexts, thus emphasizing the autonomy of the self at the expense of family and community. Online Materials My impression is that Victorian life-writing is currently better served by books than by online resources. There seem to be few general Web sites other than University module outlines and reading lists; for specific authors, on the other hand, there are too many to list here. So the only site I'd recommend is The Victorian Web: http://.victorianweb.org/genre/autobioov.html This Web site has a section called ,Autobiography Overview', which begins with an essay, ,Autobiography, Autobiographicality and Self-Representation', by George P. Landow. There are sections on other aspects of Victorian autobiography, including ,Childhood as a Personal Myth', autobiography in Dickens and Elizabeth Barrett Browning, and a list of ,Suggested Readings'. Each section is quite short, but summarizes the core issues succinctly. Sample Syllabus This sample syllabus takes students through the landmarks of Victorian life-writing, and demonstrates the development of a counter-culture away from the mainstream ,classic male life' (if there ever was such a thing) , culminating in the paired diaries of Arthur Munby (civil servant) and Hannah Cullwick (servant). Numerous other examples could have been chosen, but for those new to the genre, this is a fairly classic syllabus. One week only could be spent on the ,classic male texts' if students are more interested in pursuing other areas. Opening Session Open debate about the definition of Victorian ,life-writing' and its many varieties; differences between autobiography, autobiographical fiction, diary, letters, biography, collective biography, and memoir; the class could discuss samples of selected types, such as David Copperfield, Father and Son, Ruskin's Praeterita, and Gaskell's Life of Charlotte Brontë. Alternatively, why not just begin with Stave Two of Dickens's A Christmas Carol (1843), in which the First Spirit takes Scrooge back through his childhood and youth? This is a pretty unique type of life-writing, with Scrooge ,laughing and crying' as his childhood and youth are revealed to him in a series of flashbacks (a Victorian version of ,This is Your Life?'). The dual emotions are important to note at this stage and will prompt subsequent discussions of sentimentality and writing for comic effect later in the course. Week 2 Critical landmarks: discussion of important stages in the evolution of critical approaches to life-writing, including classics such as Georges Gusdorf's ,Conditions and Limits of Autobiography', in Autobiography: Essays Theoretical and Critical, ed. James Olney (Princeton, NJ: Princeton University Press, 1980), 28,47; Philippe Lejeune's ,The Autobiographical Pact', in On Autobiography, ed. Paul John Eakin, trans. Katherine Leary (original essay 1973; Minneapolis: University of Minnesota Press, 1989), 3,30; and Paul De Man's ,Autobiography as De-Facement', Modern Language Notes 94 (1979): 919,30. This will provide a critical framework for the rest of the course. Weeks 3,4 Extracts from the ,male classics' of Victorian life-writing: J. S. Mill's Autobiography (1873), Ruskin's Praeterita (1885,89), and Newman's Apologia pro Vita Sua (1864). What do they think is important and what do they miss out? How open or otherwise are they about their family and personal lives? Are these essentially ,lives of the mind'? How self-aware are they of autobiographical structures? Are there already signs that the ,classic male life' is fissured and unconventional? An option here would be to spend the first week focusing on male childhoods, and the second on career trajectories. Perhaps use Martin Danahay's theory of the ,autonomous individual' (see above) to provide a critical framework here: how is the ,Other' (parents, Harriet Taylor) treated in these texts? Weeks 5,6 Victorian women's autobiography: Harriet Martineau's Autobiography (1877) and Margaret Oliphant's Autobiography (1899): in many ways these are completely unalike, Martineau's being ordered around the idea of steady mental growth and public recognition, while Oliphant's is deeply emotional and disordered. Can we therefore generalize about ,women's autobiography'? What impact did they have on Victorian theories of life-writing? Students might like to reconsider Jane Eyre as an ,autobiography' alongside these and compare scenes of outright rebellion. The way each text handles time and chronology is also fascinating: Martineau's arranged to highlight stages of philosophical development, while Oliphant's switches back and forth in a series of ,flashbacks' to her happier youth as her surviving two sons die ,in the text', interrupting her story. Week 7 Black women's autobiography: how does Wonderful Adventures of Mrs Seacole in Many Lands (1857) differ from the Martineau and Oliphant autobiographies? What new issues and genre influences are introduced by a Caribbean/travelogue perspective? Another key text would be Harriet Jacobs's Incidents in the Life of a Slave-Girl (1861). How representative and how individual are these texts? Do these authors see themselves as representing their race as well as their class and sex? Week 8 Working-class autobiography: Possible texts here could be John Burnett's Useful Toil (Allen Lane, 1974, Penguin reprint); Carolyn Steedman's edition of John Pearman's The Radical Soldier's Tale (Routledge, 1988) and the mini oral biographies in Henry Mayhew's London Labour and the London Poor (1861,62) (e.g., the Water-Cress Seller). There is also a new Broadview edition of Factory Lives (2007) edited by James R. Simmons, with an introduction by Janice Carlisle. This contains four substantial autobiographical texts (three male, one female) from the mid-nineteenth century, with supportive materials. Samuel Bamford's Passages in the Life of a Radical (1839,42; 1844) and Early Days (1847,48) are further options. Students should also read Regenia Gagnier's Subjectivities: A History of Self-Representation in Britain 1832,1910 (Oxford University Press, 1991). Week 9 Biography: Victorian Scandal: focus on two scandals emerging from Victorian life-writing: Gaskell's Life of Charlotte Brontë (1857) (the Branwell Brontë/Lady Scott adultery scandal), and Froude's allegations of impotence in his Life of Carlyle (1884). See Trev Broughton's ,Impotence, Biography, and the Froude-Carlyle Controversy: ,Revelations on Ticklish Topics', Journal of the History of Sexuality, 7.4 (Apr. 1997): 502,36 (in addition to her Men of Letters cited above). The biographies of the Benson family written about and by each other, especially E. F. Benson's Our Family Affairs 1867,1896 (London: Cassell, 1920) reveal the domestic unhappiness of the family of Gladstone's Archbishop of Canterbury, Edward White Benson, whose children and wife were all to some extent homosexual or lesbian. Another option would be Edmund Gosse's Father and Son (1907) in which the son's critical stance towards his father is uneasy and complex in its mixture of comedy, pity, shame, and resentment. Week 10 Diaries: Arthur Munby's and Hannah Cullwick's relationship (they were secretly married, but lived as master and servant) and diaries, Munby: Man of Two Worlds: The Life and Diaries of Arthur Munby, ed. Derek Hudson (John Murray, 1972), and The Diaries of Hannah Cullwick: Victorian Maidservant, ed. Liz Stanley (New Brunswick, NJ: Rutgers University Press, 1984): issues of gender and class identity; the idealization of the working woman; the two diaries compared. Half the class could read one diary and half the other and engage in a debate about the social and sexual fantasies adopted by each diarist. It would also be sensible to leave time for an overview debate about the key issues of Victorian life-writing which have emerged from this module, future directions for research, and current critical developments. Focus Questions 1To what extent does Victorian autobiography tell an individual success story? Discuss with reference to two or three contrasting examples. 2,All life writing is time writing' (Jens Brockmeier). Examine the way in which Victorian life-writers handle the interplay of narrative, memory, and time. 3To what extent do you agree with the view that Victorian life-writing was ,a form of communication that appeared intimate and confessional, but which was in fact distant and controlled' (Donna Loftus)? 4,Bamford was an autobiographer who did not write an autobiography' (Martin Hewitt). If autobiography is unshaped and uninterpreted, what alternative purposes does it have in narrating a life to the reader? 5,Victorian life-writing is essentially experimental, unstable, and unpredictable.' How helpful is this comment in helping you to understand the genre? [source] Kinetics of Stable Free Radical Mediated Polymerization inside Submicron ParticlesMACROMOLECULAR THEORY AND SIMULATIONS, Issue 9 2007Hidetaka Tobita Abstract Controlled/living radical polymerization systems in which the active period is extremely small, ,A,,,1, such as the cases of stable free radical mediated polymerization (or nitroxide mediated polymerization) and atom transfer radical polymerization, are considered theoretically. The polymerization rate, Rp, for such systems increases by lowering the trapping agent concentration [X]. When the polymerization is conducted inside small particles, Rp decreases with D below the diameter Dp,SMC at which a single molecule concentration (SMC) is equal to [X]bulk. On the other hand, when the average number of trapping agents in a particle is smaller than about 10, the fluctuation of nX among particles is significant, which leads to a larger Rp than in the cases where all particles contain the same nX. Because of the effects of SMC and fluctuation, Rp may show an acceleration window, Dp,SMC,<,Dp,<,Dp,Fluct where Rp is slightly larger than that in bulk. [source] Estimation of Aqueous-Phase Reaction Rate Constants of Hydroxyl Radical with Phenols, Alkanes and AlcoholsMOLECULAR INFORMATICS, Issue 11-12 2009Ya-nan Wang Abstract A quantitative structure activity relationship (QSAR) model was developed for the aqueous-phase hydroxyl radical reaction rate constants (kOH) employing quantum chemical descriptors and multiple linear regressions (MLR). The QSAR development followed the OECD guidelines, with special attention to validation, applicability domain (AD) and mechanistic interpretation. The established model yielded satisfactory performance: the correlation coefficient square (R2) was 0.905, the root mean squared error (RMSE) was 0.139, the leave-many-out cross-validated QLMO2 was 0.806, and the external validated QEXT2 was 0.922 log units. The AD of the model covering compounds of phenols, alkanes and alcohols, was analyzed by Williams plot. The main molecular structural factors governing kOH are the energy of the highest occupied molecular orbital (EHOMO), average net atomic charges on hydrogen atoms (), molecular surface area (MSA) and dipole moment (,). It was concluded that kOH increased with increasing EHOMO and MSA, while decreased with increasing and ,. [source] Determination of Wavelength-Specific UV Protection Factors of Sunscreens in Intact Skin by EPR Measurement of UV-Induced Reactive Melanin RadicalPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Leslie Lund ABSTRACT There remains an unmet need for skin tissue-based assays for the measurement of the UVA protection and efficacy of sunscreens. Here we describe development of a novel electron paramagnetic resonance assay that uses the photogeneration of reactive melanin radical as a measure of UV light penetration to melanocytes in situ in skin. We have used areas of focal melanocytic hyperplasia in the skin of Monodelphis domestica to model the human nevus. We show that we are able to use this assay to determine the monochromatic protection factors (mPF) of research and commercial sunscreens at specific narrow wavebands of UVB, UVA and blue visible light. Both commercial sunscreens, a sun protection factor (SPF) 4 and an SPF 30 product, had mPFs in the UVB range that correlated well with their claimed SPF. However, their mPF in the UVA ranges were only about one-third of claimed SPF. This technique can be used to design and assay sunscreens with optimally balanced UVA and UVB protection. [source] Power: A Pragmatist, Deliberative (and Radical) View*THE JOURNAL OF POLITICAL PHILOSOPHY, Issue 3 2008Amit Ron First page of article [source] Radical and Radical Ion Reactivity in Nucleic Acid Chemistry.ANGEWANDTE CHEMIE, Issue 25 2010Biology Series., Reactive Intermediates in Chemistry John Wiley & Sons, Hoboken 2009. 458,S., geb., 99.90,,.,ISBN 978-0470255582 [source] Innentitelbild: A Silyl Radical formed by Muonium Addition to a Silylene (Angew. Chem.ANGEWANDTE CHEMIE, Issue 16 201016/2010) Bestrahlung des stabilen SilylensN,N,-Bis(2,6-diisopropylphenyl)-1,3-diaza-2-silacyclopent-4-en-2-yliden mit Myonen ergibt ein Radikal, das R. West et,al. anhand seines Myonenspinrotationsspektrums als das monomere Myonium-Addukt identifizierten. Wie in der Zuschrift auf S.,2955,ff. geschildert wird, liegt die Myon-Hyperfeinkonstante bei 931,MHz, was der bei weitem größte je bestimmte Wert für ein freies Radikal ist. [source] A Silyl Radical formed by Muonium Addition to a Silylene,ANGEWANDTE CHEMIE, Issue 16 2010Amitabha Mitra Dr. Rekordradikal: Die Bestrahlung des stabilen Silylens N,N,-Bis(2,6-diisopropylphenyl)-1,3-diaza-2-silacyclopent-4-en-2-yliden mit Myonen führt zu einem Radikal, das anhand seines Myonenspinrotations(,SR)-Spektrums als das monomere Myonium-Addukt identifiziert wurde. Die Myon-Hyperfeinkonstante für dieses Radikal beträgt 931,MHz , der höchste je bestimmte Wert für ein freies Radikal. [source] All-Organic Discotic Radical with a Spin-Carrying Rigid-Core Showing Intracolumnar Interactions and Multifunctional Properties,ANGEWANDTE CHEMIE, Issue 35 2009Sonia Castellanos Das diskotische flüssigkristalline Radikal 1, das im festen Zustand und in Lösung sehr stabil ist, bildet oberhalb der Raumtemperatur eine enantiotrope geordnete hexagonale columnare Mesophase mit magnetischen Wechselwirkungen zwischen den Molekülspins. Radikal 1 ist elektrochemisch amphoter, und seine Absorptionen und Lichtemissionen decken den roten Bereich des sichtbaren Spektrums ab. [source] Reagents for Radical and Radical Ion Chemistry.Handbook of Reagents for Organic Synthesis.ANGEWANDTE CHEMIE, Issue 32 2009Herausgegeben von David Crich. John Wiley & Sons, Hoboken 2008. 722,S., geb., 129.00,,.,ISBN 978-0470065365 [source] Confessions of a Desk-Bound RadicalANTIPODE, Issue 3 2008Don Mitchell First page of article [source] Radical Producing and Consuming Reactions of Hemoglobin: How Can We Limit Toxicity?ARTIFICIAL ORGANS, Issue 2 2009Chris E. Cooper Abstract Hemoglobin has a range of enzymatic activities that can affect its putative pharmacological role as an extracellular oxygen carrier. In the presence of peroxides, deoxyhemoglobin and methemoglobin can produce free radicals and induce lipid peroxidation. Oxyhemoglobin can oxidize the free radical nitric oxide to nitrate, yet deoxyhemoglobin can produce nitric oxide from nitrite. These enzymatic reactions can induce or diminish toxic side reactions when hemoglobin is added in vivo. For example the removal of the free radical vasodilator nitric oxide, or the addition of the lipid-derived vasoconstrictor F2-isoprostane, will both alter blood flow and blood pressure. In order to determine the dominant effects it is necessary to design molecules with differing radical reactivities. Molecules have been designed with these modifications and this article will review their role in determining mechanism as well as their possible functionality as blood substitutes. [source] Radical versus partial nephrectomyCANCER, Issue 7 2009Effect on overall, noncancer mortality Abstract BACKGROUND: Relative to radical nephrectomy (RN), partial nephrectomy (PN) performed for renal cell carcinoma (RCC) may protect from non-cancer-related deaths. The authors tested this hypothesis in a cohort of PN and RN patients. METHODS: The Surveillance, Epidemiology, and End Results-9 database allowed identification of 2198 PN (22.4%) and 7611 RN (77.6%) patients treated for T1aN0M0 RCC between 1988 and 2004. Analyses matched for age, year of surgery, tumor size, and Fuhrman grade addressed the effect of nephrectomy type (RN vs PN) on overall mortality (Cox regression models) and on non-cancer-related mortality (competing-risks regression models). RESULTS: Relative to PN, RN was associated with 1.23-fold (P = .001) increased overall mortality rate, which translated into a 4.9% and 3.1% absolute increase in mortality at 5 and 10 years after surgery, respectively. Similarly, non-cancer-related death rate was significantly higher after RN in competing-risks regression models (P < .001), which translated into a 4.6% and 4.5% absolute increase in non-cancer-related mortality at 5 and 10 years after surgery, respectively. CONCLUSIONS: Relative to PN, RN predisposes to an increase in overall mortality and non-cancer-related death rate in patients with T1a RCC. In consequence, PN should be attempted whenever technically feasible. Selective referrals should be considered if PN expertise is unavailable Cancer 2009. © 2009 American Cancer Society. [source] Adenosyl Radical: Reagent and Catalyst in Enzyme ReactionsCHEMBIOCHEM, Issue 5 2010E. Neil G. Marsh Prof. Abstract Adenosine is undoubtedly an ancient biological molecule that is a component of many enzyme cofactors: ATP, FADH, NAD(P)H, and coenzyme A, to name but a few, and, of course, of RNA. Here we present an overview of the role of adenosine in its most reactive form: as an organic radical formed either by homolytic cleavage of adenosylcobalamin (coenzyme B12, AdoCbl) or by single-electron reduction of S -adenosylmethionine (AdoMet) complexed to an iron,sulfur cluster. Although many of the enzymes we discuss are newly discovered, adenosine's role as a radical cofactor most likely arose very early in evolution, before the advent of photosynthesis and the production of molecular oxygen, which rapidly inactivates many radical enzymes. AdoCbl-dependent enzymes appear to be confined to a rather narrow repertoire of rearrangement reactions involving 1,2-hydrogen atom migrations; nevertheless, mechanistic insights gained from studying these enzymes have proved extremely valuable in understanding how enzymes generate and control highly reactive free radical intermediates. In contrast, there has been a recent explosion in the number of radical-AdoMet enzymes discovered that catalyze a remarkably wide range of chemically challenging reactions; here there is much still to learn about their mechanisms. Although all the radical-AdoMet enzymes so far characterized come from anaerobically growing microbes and are very oxygen sensitive, there is tantalizing evidence that some of these enzymes might be active in aerobic organisms including humans. [source] ChemInform Abstract: Novel Radical Cyclization Method Accompanied by Elimination of Hydrazyl Radical.CHEMINFORM, Issue 34 2010Shoju Kobayashi Abstract A novel radical cyclization is studied, which is accompanied by elimination of the hydrazyl radical. [source] ChemInform Abstract: B-Alkylcatecholborane-Mediated Tandem Radical Conjugated Addition,Aldol Cyclization.CHEMINFORM, Issue 2 2010Alice Beauseigneur Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Versatile Radical-Based Approach to O-Alkylated Hydroxylamines and Oximes.CHEMINFORM, Issue 20 2009Beatrice Quiclet-Sire Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Decarboxylative Reduction of Free Aliphatic Carboxylic Acids by Photogenerated Cation Radical.CHEMINFORM, Issue 15 2008Yasuharu Yoshimi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Quinine Synthesis Studies: A Radical,Ionic Annulation via Mn-Mediated Addition to Chiral N-Acylhydrazones.CHEMINFORM, Issue 12 2008Chandra Sekhar Korapala Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Stability of the Hydrogen Trioxy Radical via Infrared Action Spectroscopy.CHEMINFORM, Issue 34 2007Craig Murray Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Radical,Molecule Reactions for Aromatic Growth: A Case Study for Cyclopentadienyl and Acenaphthylene.CHEMINFORM, Issue 3 2007Dong Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||