3,020 research outputs found
3D nanowire Pt catalysts with enhanced stability for the oxygen reduction reaction
No full textWe report that self-supporting mesoporous platinum 3D nanowires with a single diamond (SD) morphology and a high specific surface area of 40.4 m2 g-1 demonstrated enhanced stability toward the oxygen reduction reaction (ORR). These were found to be superior to commercially available carbon-supported Pt nanoparticles (Pt/C). After 1000 potential cycles, there was a 21% loss in surface area for SD-Pt, as compared with a 40.3% loss for Pt/C with no reduction in their half-wave potential (measured at J = 3.0 mA cm-2), whereas the Pt/C catalyst showed a 11.9 mV decrease. Our findings revealed that our SD-Pt thin films also exhibited excellent ORR activity, which offers significant potential for their application as high-performance cathode materials in alkaline fuel cells.</p
DNA Damage, Repair, and Cancer Metabolism
No full textAlthough there has been a renewed interest in the field of cancer metabolism in the last decade, the link between metabolism and DNA damage/DNA repair in cancer has yet to be appreciably explored. In this review, we examine the evidence connecting DNA damage and repair mechanisms with cell metabolism through three principal links. (1) Regulation of methyl- and acetyl-group donors through different metabolic pathways can impact DNA folding and remodeling, an essential part of accurate double strand break repair. (2) Glutamine, aspartate, and other nutrients are essential for de novo nucleotide synthesis, which dictates the availability of the nucleotide pool, and thereby influences DNA repair and replication. (3) Reactive oxygen species, which can increase oxidative DNA damage and hence the load of the DNA-repair machinery, are regulated through different metabolic pathways. Interestingly, while metabolism affects DNA repair, DNA damage can also induce metabolic rewiring. Activation of the DNA damage response (DDR) triggers an increase in nucleotide synthesis and anabolic glucose metabolism, while also reducing glutamine anaplerosis. Furthermore, mutations in genes involved in the DDR and DNA repair also lead to metabolic rewiring. Links between cancer metabolism and DNA damage/DNA repair are increasingly apparent, yielding opportunities to investigate the mechanistic basis behind potential metabolic vulnerabilities of a substantial fraction of tumors
New Evidence on Allyn Young's Style and Influence as a Teacher
No full textThis paper publishes the hitherto unpublished correspondence between Allyn Abbott Young's biographer Charles Blitch and 17 of Young's former students or associates. Together with related biographical and archival material, the paper shows the way in which this adds to our knowledge of Young's considerable influence as a teacher upon some of the twentieth century's greatest economists. The correspondents are as follows: James W Angell, Colin Clark, Arthur H Cole, Lauchlin Currie, Melvin G de Chazeau, Eleanor Lansing Dulles, Howard S Ellis, Frank W Fetter, Earl J Hamilton, Seymour S Harris, Richard S Howey, Nicholas Kaldor, Melvin M Knight, Bertil Ohlin, Geoffrey Shepherd, Overton H Taylor, and Gilbert Walker
S-heterocyclic carbene with a disilane backbone
No full textPT: J; CR: AKASAKA T, 1999, ORG LETT, V1, P1509 AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 ALCARAZO M, 2004, J AM CHEM SOC, V126, P13242 ALDER RW, 1999, CHEM COMMUN 0207, P241 ARDUENGO AJ, 1991, J AM CHEM SOC, V113, P361 ARDUENGO AJ, 1995, J AM CHEM SOC, V117, P11027 BAZINET P, 2003, J AM CHEM SOC, V123, P13314 BECKE AD, 1988, PHYS REV A, V38, P30989 BECKE AD, 1993, J CHEM PHYS, V98, P5648 BOURISSOU D, 2000, CHEM REV, V100, P39 DESPAGNETAYOUB E, 2004, J AM CHEM SOC, V126, P10198 DESPAGNETAYOUB E, 2005, ORGANOMETALLICS, V24, P338 ENDERS D, 2001, J ORGANOMET CHEM, V617 FABIAN J, 2000, J ORG CHEM, V65, P8940 FEKETE A, 2002, J ORGANOMET CHEM, V643, P278 FRANCL MM, 1982, J CHEM PHYS, V77, P3654 GRAHAM DC, 2005, J PHYS ORG CHEM, V18, P298 HAHN FE, 2000, ANGEW CHEM INT EDIT, V39, P541 HAHN FE, 2000, ANGEW CHEM, V112, P551 HERRMANN WA, 2002, ANGEW CHEM INT EDIT, V41, P1290 HERRMANN WA, 2002, ANGEW CHEM, V114, P1342 HILLIER AC, 2002, J ORGANOMET CHEM, V653, P69 HIRSCH A, 1993, CHEM BER, V126, P1061 HOZ T, 1993, CHEM SULFUR CONTAINI, P1 ISHITSUKA MO, 2004, TETRAHEDRON LETT, V45, P6321 JAFARPOUR L, 2001, ADV ORGANOMET CHEM, V46, P181 KRAHULIC KE, 2005, J AM CHEM SOC, V127, P4142 KYUSHIN S, 1994, CHEM LETT, P997 KYUSHIN S, 1996, J ORGANOMET CHEM, V521, P413 KYUSHIN S, 2000, CHEM LETT 0505, P494 LEE C, 1988, PHYS REV B, V37, P785 LIU MTH, 2003, J ORG CHEM, V68, P7471 MARTIN D, 2005, ANGEW CHEM INT EDIT, V44, P1700 MARTIN D, 2005, ANGEW CHEM, V117, P1728 MATSUMOTO H, 2000, J ORGANOMET CHEM, V611, P52 MOSS RA, 1980, ACCOUNTS CHEM RES, V13, P58 MOSS RA, 1988, J AM CHEM SOC, V110, P4443 OTTO M, 2004, J AM CHEM SOC, V126, P1016 PERRY MC, 2003, TETRAHEDRON-ASYMMETR, V14, P951 PIETRO WJ, 1982, J AM CHEM SOC, V104, P5039 WAKAHARA T, 2002, J AM CHEM SOC, V124, P9465 WIBERG N, 2002, CHEM-EUR J, V8, P2730 WIN WW, 1994, J ORG CHEM, V59, P5817; NR: 43; TC: 1; J9: ANGEW CHEM INT ED; PG: 4; GA: 989STSource type: Electronic(1
Angiotensin II and the control of humoral catecholamine release in fish.
No full textThe main goal of this thesis was to determine the relative importance of non-cholinergic secretagogues, primarily angiotensin II (Ang II), in the control of catecholamine release from the chromaffin tissue of fish. In rainbow trout (Oncorhynchus mykiss), immunohistochemical techniques and an in situ posterior cardinal vein (PCV) perfusion preparation provided direct evidence that Ang II can elicit catecholamine release from the chromaffin tissue via specific Ang II binding sites. Whereas the contribution of the renin-angiotensin system (RAS) to blood pressure recovery was largely indirect and relied on an Ang II-mediated secretion of catecholamines, the contribution from the sympathetic nervous system (SNS) was direct and relied on both plasma catecholamines and sympathetic nerves. In the American eel (Anguilla rostrata), injections of Ang II had no effect on humoral catecholamine release in either in situ PCV perfusion preparations or in chronically cannulated fish. The pressor effects of exogenous Ang II could not be attributed to any change in plasma catecholamine levels and the SNS does not appear to be an essential contributor to cardiovascular homeostasis during hypotension in the eel. The contributions of Ang II and humoral catecholamines to cardiovascular control were also investigated in an elasmobranch, the spiny dogfish ( Squalus acanthias). Whereas the contribution of catecholamines was direct, Ang II indirectly contributed to cardiovascular control by dose-dependent stimulation of catecholamine release. Results suggest that the control of catecholamine release from the chromaffin tissue of M. glutinosa can be achieved through hormonal and/or paracrine means and that ACTH, serotonin, and adenosine may all be involved. In summary, Ang II is a potent secretagogue of humoral catecholamine release in O. mykiss and S. acanthias. In both species, Ang II plays a significant role in the control of catecholamine release during acute hypotension, and this interaction represents an important physiological response for the maintenance of cardiovascular homeostasis. On the other hand, although previously suggested, Ang II does not appear to be a secretagogue of humoral catecholamine release in either A. rostrata or M. glutinosa. (Abstract shortened by UMI.
Angiotensin II and the control of humoral catecholamine release in fish.
No full textThe main goal of this thesis was to determine the relative importance of non-cholinergic secretagogues, primarily angiotensin II (Ang II), in the control of catecholamine release from the chromaffin tissue of fish. In rainbow trout (Oncorhynchus mykiss), immunohistochemical techniques and an in situ posterior cardinal vein (PCV) perfusion preparation provided direct evidence that Ang II can elicit catecholamine release from the chromaffin tissue via specific Ang II binding sites. Whereas the contribution of the renin-angiotensin system (RAS) to blood pressure recovery was largely indirect and relied on an Ang II-mediated secretion of catecholamines, the contribution from the sympathetic nervous system (SNS) was direct and relied on both plasma catecholamines and sympathetic nerves. In the American eel (Anguilla rostrata), injections of Ang II had no effect on humoral catecholamine release in either in situ PCV perfusion preparations or in chronically cannulated fish. The pressor effects of exogenous Ang II could not be attributed to any change in plasma catecholamine levels and the SNS does not appear to be an essential contributor to cardiovascular homeostasis during hypotension in the eel. The contributions of Ang II and humoral catecholamines to cardiovascular control were also investigated in an elasmobranch, the spiny dogfish ( Squalus acanthias). Whereas the contribution of catecholamines was direct, Ang II indirectly contributed to cardiovascular control by dose-dependent stimulation of catecholamine release. Results suggest that the control of catecholamine release from the chromaffin tissue of M. glutinosa can be achieved through hormonal and/or paracrine means and that ACTH, serotonin, and adenosine may all be involved. In summary, Ang II is a potent secretagogue of humoral catecholamine release in O. mykiss and S. acanthias. In both species, Ang II plays a significant role in the control of catecholamine release during acute hypotension, and this interaction represents an important physiological response for the maintenance of cardiovascular homeostasis. On the other hand, although previously suggested, Ang II does not appear to be a secretagogue of humoral catecholamine release in either A. rostrata or M. glutinosa. (Abstract shortened by UMI.
How has the art education that I have received impacted on my practice as an art maker?
No full textThis thesis is a written account of my analysis of the art education that I received during my undergraduate Interdisciplinary Art and Design BA(hon)s degree and University Campus Barnsley. The investigation and written thesis were undertaken as part of a Practice led research degree at Huddersfield University. The aim of the research was twofold. First to develop an understanding of the History of Art Education in the area of South Yorkshire and secondly to return to analyse the art work I made as part of my undergraduate degree. This study then became the focus of the series of practical Paintings and drawings which were the main focal point of the Master degree.
The thesis is an account of my analysis of how my art practice developed in response to the practical type of education that I received. It identifies specific art makers and art movements that have had a direct impact on how my painting process matured and changed. The thesis goes on to identify the specific genre of literature that influenced my practical development and the use of metaphor in paintings and drawings . It then goes on to give a written account of the specific examples of visual metaphors in my practical Masters work and analyses their origins, continued development and what they represent.
The issue of class and social equality is identified and the metaphor clearly dissected and explained. The thesis then outlines the development of the class metaphor into an education metaphor which represents my belief that a university education can aid the act of social mobility. This theory is justified by my experience of having returned to full time higher education as a working class mature woman and having achieved a level of social mobility which was aided by my gaining a first class BA(hon)s degree which enabled me to apply for and complete a Masters Degree
A "KEYHOLE" MODEL OF IVR TO ACCOUNT FOR THE CONTRASTING EIGENSTATE-RESOLVED INFRARED SPECTRA OF 1-BUTYNE AND ETHANOL
No full text A. M. de Souza, D. Kaur, and D. S. Perry. J. Chem. Phys. 88, 4659 (1988). A. Mcllroy, and D. J. Nesbitt, J. Chem. Phys. 92, 2229 (1990).Author Institution: Department of Chemistry, University of AkronRecent molecular eigenstate-resolved infrared spectra 1-butyne1-2 and ethanol have given insight into the nature of the couplings responsible for intramolecular vibrational redistribution (IVR) at low energies. In the alkynyl C-II band of 1-butyne, the pattern of the coupling is independent of molecular rotation and is therefore attributed to anharmoic vibrational interactions. In contrast, strong rotational affects are observed in the methyl stretching region of ethanol indicating a Coriolis and/or centrifugal coupling mechanism. The present data on the methyl region of 1-butyne does not exhibit this kind of dramatic rotational effect. Despite the apparent difference in coupling mechanism, the interaction widths and average matrix elements are of similar size in both moleculcs. A ``keyhole'' model of IVR will be presented in order to account for the similarities and difference between the two molecules. According to the model, the primary coupling between the zero-order C-H stretch and the bath is similar for both molecules. i. e. anharmonic in nature. The difference between the molecules lies in way bath states couple to each other. In 1-butyne, the bath-bath coupling is mainly anharmonic in nature but in ethanol Coriolis and/or anharmonic coupling among the bath states is also active. Therefore in ethanol, and are no longer good quantum numbers and it is possible for IVR to explore the whole of rotational-vibrational phase space
Hundreds of variants clustered in genomic loci and biological pathways affect human height
No full textMost common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits(1), but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait(2,3). The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways
Measurement of J/ψ and ψ(2S) prompt double-differential cross sections in pp collisions at √s =7 TeV.
No full textPublished by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.The double-differential cross sections of promptly produced J/ψ and ψ(2S) mesons are measured in pp collisions at √s =7 TeV, as a function of transverse momentum p_{T} and absolute rapidity |y|. The analysis uses J/ψ and ψ(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90 fb^{-1}, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to p_{T}=120 and 100 GeV for the J/ψ and ψ(2S), respectively, when integrated over the interval |y|<1.2. The ratio of the ψ(2S) to J/ψ cross sections is also reported for |y|<1.2, over the range 10<p_{T}<100 GeV. These are the highest p_{T} values for which the cross sections and ratio have been measured
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