991 resultados para Ellsworth, Oliver, 1745-1807.


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Digital image

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Digital image

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Digital image

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cobalt(III) complexes [Co(pnt)(B)(2)](NO3)(2) (1-3) of pyridine-2-thiol (pnt) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d: 2',3'-f]quinoxaline (dpq in 2) and dipyrido[3,2-a:2',3'-c] phenazine (dppz in 3), have been prepared, characterized and their photo-induced anaerobic DNA cleavage activity studied. The crystal structure of 1a as mixed ClO4- and PF6- salt of 1 shows a (CoN5S)-N-III coordination geometry in which the pnt and phen showed N,S- and N,N-donor binding modes, respectively. The complexes exhibit Co(III)/Co(II) redox couple near -0.3 V (vs. SCE) in 20% DMF-Tris-HCl buffer having 0.1 M TBAP. The complexes show binding propensity to calf thymus DNA giving K-b values within 2.2 x 10(4)-7.3 x 10(5) M-1. Thermal melting and viscosity data suggest DNA surface and/or groove binding of the complexes. The complexes show significant anaerobic DNA cleavage activity in red light under argon atmosphere possibly involving sulfide anion radical or thiyl radical species. The DNA cleavage reaction under aerobic medium in red light is found to involve both singlet oxygen and hydroxyl radical pathways. The dppz complex 3 shows non-specific BSA and lysozyme protein cleavage activity in UV-A light of 365 nm via both hydroxyl and singlet oxygen pathways. The dppz complex 3 exhibits photocytotoxicity in HeLa cervical cancer cells giving IC50 values of 767 nM and 19.38 mu M in UV-A light of 365 nm and in the dark, respectively. A significant reduction of the dark toxicity of the dppz base (IC50 = 8.34 mu M in dark) is observed on binding to the cobalt(III) center.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The assembly of influenza A virus at the plasma membrane of infected cells leads to release of enveloped virions that are typically round in tissue culture-adapted strains but filamentous in strains isolated from patients. The viral proteins hemagglutinin (HA), neuraminidase (NA), matrix protein 1 (M1), and M2 ion channel all contribute to virus assembly. When expressed individually or in combination in cells, they can all, under certain conditions, mediate release of membrane-enveloped particles, but their relative roles in virus assembly, release, and morphology remain unclear. To investigate these roles, we produced membrane-enveloped particles by plasmid-derived expression of combinations of HA, NA, and M proteins (M1 and M2) or by infection with influenza A virus. We monitored particle release, particle morphology, and plasma membrane morphology by using biochemical methods, electron microscopy, electron tomography, and cryo-electron tomography. Our data suggest that HA, NA, or HANA (HA plus NA) expression leads to particle release through nonspecific induction of membrane curvature. In contrast, coexpression with the M proteins clusters the glycoproteins into filamentous membrane protrusions, which can be released as particles by formation of a constricted neck at the base. HA and NA are preferentially distributed to differently curved membranes within these particles. Both the budding intermediates and the released particles are morphologically similar to those produced during infection with influenza A virus. Together, our data provide new insights into influenza virus assembly and show that the M segment together with either of the glycoproteins is the minimal requirement to assemble and release membrane-enveloped particles that are truly virus-like.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Copper(I) complexes with {Cu(μ2-S)N}4 and {Cu(μ3-S)N}12 core portions of butterfly-shaped or double wheel architectures have been isolated in the reaction of Cu(I) with the Schiff base ligand C6H4(CHNC6H4S)2, aiso-abtâ, under different conditions. View the MathML source containing the tetranuclear electroneutral complex View the MathML source is formed by the reaction of CuI in acetonitrilic solution and recrystallization from DMF, whereas View the MathML source containing dodecanuclear View the MathML source wheels is accessible starting from CuBF4. Complexes 2 and 4 represent the first examples of cyclic complexes with the same overall stoichiometry but different ring sizes. The ligand induces two different coordination environments around copper(I) by switching between μ2- and μ3-sulfur bridging modes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Nickel rich NiTi films were sputter deposited on p-doped Si left angle bracket1 0 0right-pointing angle bracket substrates maintained at 300 °C. The films were subsequently solution treated at 700 °C for 30 min followed by ageing at 400 and 500 °C for 5 h. The microstructure of the films was examined by TEM and these studies revealed that the NiTi films were mostly amorphous in the as-deposited condition. The subsequent solution treatment and ageing resulted in crystallization of the films with the film aged at 400 °C exhibiting nanocrystalline grains and three phases viz. B2 (austenite), R and Ni3Ti2 whereas the film aged at 500 °C shows micron sized grains and two phases viz. R and Ni3Ti2. Nanoindentation studies revealed that the nature of the load versus indentation depth response for the films aged at 400 and 500 °C was different. For the same load, the indenter penetrated to a much greater depth for the film aged at 400 °C as compared to the film aged at 500 °C. Also the ratio of the residual indentation depth (hf) to maximum indentation depth (hmax) is lower for the film aged at 400 °C as compared to the film aged at 500 °C. This was attributed to the occurrence of stress induced martensitic transformation of the B2 phase present in the film aged at 400 °C during indentation loading which results in a transformation strain in addition to the normal elastic and plastic strains and its subsequent recovery on unloading. The hardness and elastic modulus measured using the Oliver and Pharr analysis was also found to be lower for the film aged at 400 °C as compared to the film aged at 500 °C which was also primarily attributed to the same effect.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The standard Gibbs energies of formation of RuO2 and OsO2 at high temperature have been determined with high precision, using a novel apparatus that incorporates a buffer electrode between the reference and working electrodes, The buffer electrode absorbs the electrochemical flux of oxygen through the solid electrolyte from the electrode with higher oxygen chemical potential to the electrode with lower oxygen potential, The buffer electrode prevents polarization of the measuring electrode and ensures accurate data, The standard Gibbs energies of formation (Delta(f)G degrees) of RuO2, in the temperature range of 900-1500 K, and OsO2, in the range of 900-1200 K, can be represented by the equations Delta(f)G degrees(RuO2)(J/mol) = -324 720 + 354.21T - 23.490T In T Delta(f)G degrees(OsO2)(J/mol) = -304 740 + 318.80T - 18.444T In T where the temperature T is given in Kelvin and the deviation of the measurement is +/- 80 J/mol, The high-temperature heat ;capacities of RuO2 and OsO2 are measured using differential scanning calorimetry. The information for both the low- and high-temperature heat rapacity of RuO2 is coupled with the Delta(f)G degrees data obtained in this study to evaluate the standard enthalpy of formation of RuO2 at 298.15 K (Delta(f)H degrees(298.15K)). The low-temperature heat capacity of OsO2 has not been measured: therefore, the standard enthalpy and entropy of formation of OsO2 at 298.15 K (Delta(f)H degrees(298.15K) and S degrees(298.15K), respectively) are derived simultaneously through an optimization procedure from the high-temperature heat capacity and the Gibbs energy of formation. Both Delta fH degrees(298.15K) and S degrees(298.15K) are treated as variables in the optimization routine, For RuO2, the standard enthalpy of formation at 298.15 K is Delta fH degrees(298.15K) (RuO2) -313.52 +/- 0.08 kJ/mol, and that for OsO2 is Delta(f)H degrees(298.15K) (OSO2) = -295.96 +/- 0.08 kJ/mol. The standard entropy of OsO2 at 298.15 K that has been obtained from the optimization is given as S degrees(298.15K) (OsO2) = 49.8 +/- 0.2 J (mol K)(-1).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Tutkielmassa tarkastellaan yhtä kansainvälisten suhteiden ja diplomatian lähihistorian pulmallisinta haastetta, kysymystä Kosovon asemasta vuosina 1998–2010. Se oli yksi keskeisimmistä 1990-luvun Jugoslavian hajoamissotien solmukohdista ja suhtautuminen siihen jakaa edelleen kansainvälisen yhteisön rivejä maailmanlaajuisesti. Tapaus on erityisen mielenkiintoinen myös nationalismin ja historiapolitiikan kannalta, sillä Kosovo on sekä albaanien että serbien kansallisen identiteetin ydinaluetta. Varhaishistorian myytit ja etnohistorialliset kertomukset ovat olleet tärkeässä asemassa lukuisissa aluetta koetelleissa konflikteissa. Tutkimuksen lähtökohtana on historiapolitiikan lähestymistavan välttämättömyys kansainvälisesti politisoituneen ”Kosovon kysymyksen” ymmärtämisessä. Historiapolitiikan teoreettisen viitekehyksen soveltuvuuden koettelu diplomatian argumentaation ja kansainvälisten suhteiden analysoinnissa on olennainen osa tutkimuksen tehtävänasettelua, sillä varsinkaan Suomessa ei vastaavaa tutkimusta ole ennen tehty. Samalla tutkimuksen tavoitteena on luokitella, analysoida ja vertailla eri valtioiden diplomaattisten historia-argumenttien käyttöä Kosovon kysymyksen yhteydessä sekä tarkastella näiden argumenttien kautta suhtautumista kansallisiin etnohistorian tulkintoihin ja niiden käyttöön 1990-luvun retoriikassa. Tutkielman tärkeimpiä alkuperäislähteitä ovat YK:n turvallisuusneuvoston Kosovoa käsittelevien istuntojen pöytäkirjat vuosilta 1998–2010 sekä huhti- ja heinäkuussa 2009 YK:n kansainväliselle tuomioistuimelle (ICJ) toimitetut, Kosovon itsenäisyysjulistuksen lainmukaisuutta käsittelevät, kirjalliset lausunnot ja kommentit. Tutkimuskirjallisuuden osalta tutkielman tärkeimpiä lähteitä ovat muun muassa Oliver Jens Schmittin, Marc Wellerin ja Pekka Visurin teokset sekä monet albaanien ja serbien kansallisia historiakäsityksiä ilmentävät teokset. Tutkielman metodologisena apuvälineenä on sovellettu suomalaisessa tutkimuksessa aikaisemmin hyvin vähän käytettyä Karl-Georg Faberin mallia historian poliitisen käytön kategorisoimiseksi. Faberin mallia käytetään paitsi historia-argumenttien luokittelun kehikkona, myös ajattelua ohjaavana historianfilosofisena kolmitasoisena mallina. Sitä on täydennytty Chaïm Perelmanin ja Lucie Olbrechts-Tytecan retoriikan tutkimuksen teorialla. Tutkimuksen tärkeimpiä johtopäätöksiä on historiapolitiikan näkökulman ja Faberin mallin hedelmällisyyden toteaminen diplomatian argumentaation analysoinnissa. Samalla tutkimus osoittaa, että historia-argumenteilla oli (ja on edelleen) Kosovon kysymyksessä oma erityinen roolinsa, joka vaihteli ajallisesti ja teemoittain. Toisaalta kansalliset historiakäsitykset, kuten käsitys omasta kansasta uhrina, näkyivät argumenteissa selvästi, toisaalta pyrkimyksenä oli vältellä nationalistiseksi tulkittavia historia-argumentteja. Lisäksi monissa argumenteissa vaaditiin väkivaltaisen historian jättämistä taakse eurooppalaisen tulevaisuuden toivossa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The subject and methodology of biblical scholarship has expanded immense-ly during the last few decades. The traditional text-, literary-, source- and form-critical approaches, labeled historical-critical scholarship , have faced the challenge of social sciences. Various new literary, synchronic readings, sometimes characterized with the vague term postmodernism, have in turn challenged historicalcritical, and social-scientific approaches. Widened limits and diverging methodologies have caused a sense of crisis in biblical criticism. This metatheoretical thesis attempts to bridge the gap between philosophical discussion about the basis of biblical criticism and practical academic biblical scholarship. The study attempts to trace those epistemological changes that have produced the wealth of methods and results within biblical criticism. The account of the cult reform of King Josiah of Judah as reported in 2 Kings 22:1 23:30 serves as the case study because of its importance for critical study of the Hebrew Bible. Various scholarly approaches embracing 2 Kings 22:1 23:30 are experimentally arranged around four methodological positions: text, author, reader, and context. The heuristic model is a tentative application of Oliver Jahraus s model of four paradigms in literary theory. The study argues for six theses: 1) Our knowledge of the world is con-structed, fallible and theory-laden. 2) Methodological plurality is the neces-sary result of changes in epistemology and culture in general. 3) Oliver Jahraus s four methodological positions in regard to literature are also an applicable model within biblical criticism to comprehend the methodological plurality embracing the study of the Hebrew Bible. 4) Underlying the methodological discourse embracing biblical criticism is the epistemological ten-sion between the natural sciences and the humanities. 5) Biblical scholars should reconsider and analyze in detail concepts such as author and editor to overcome the dichotomy between the Göttingen and Cross schools. 6) To say something about the historicity of 2 Kings 22:1 23:30 one must bring together disparate elements from various disciplines and, finally, admit that though it may be possible to draw some permanent results, our conclusions often remain provisional.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The preparation of five different copper(I) complexes [CuSC(=NPh)(OAr)}L(n)]m (1-5) formed by the insertion of PhNCS into the Cu-OAr bond and the crystal structure analyses of three of them have been carried out. A monomeric species 1 (OAr = 2,6-dimethylphenoxide) is formed in the presence of excess PPh3 (n = 2, m = 1) and crystallizes as triclinic crystals with a = 12.419(4) angstrom, b = 13.298(7) angstrom, c = 15.936(3) angstrom, alpha = 67.09(3)-degrees, beta = 81.63(2)-degrees, gamma = 66.54(3)-degrees, V = 2224(2) angstrom3, and Z = 2. The structure was refined by the least-squares method to final R and R(w) values of 0.038 and 0.044, respectively, for 7186 unique reflections. Copper(I) 2,5-di-tert-butyl-4-methylphenoxide results in the formation of a dimeric species 2 in the presence of P(OMe)3 (n = 1, m = 2), where the coordination around Cu is trigonal. Crystals of 2 were found to be orthorhombic with a = 15.691(2) angstrom, b = 18.216(3) angstrom, c = 39.198(5) angstrom, v = 11204(3) angstrom3, and Z = 8. Least-squares refinement gave final residuals of R = 0.05 and R(w) = 0.057 with 6866 unique reflections. A tetrameric species 3 results when PPh3 is replaced by P(OMe)3 in the coordination sphere of copper(I) 2,6-dimethylphenoxide. It crystallizes in the space group P1BAR with a = 11.681 (1) angstrom, b = 13.373(2) angstrom, c = 20.127(1) angstrom, a = 88.55(l)-degrees, beta = 89.65(l)-degrees, gamma = 69.28(1)-degrees, V = 2940(l) angstrom3, and Z = 2. Least-squares refinement of the structure gave final values of 0.043 and 0.05 for R and R(w) respectively using 12214 unique reflections. In addition, a dimeric species 4 is formed when 1 equiv of PPh3 is added to the copper(I) 4-methylphenoxide, while with an excess of PPh3 a monomeric species 5 is isolated. Some interconversions among these complexes are also reported.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Psychoanalytic interpretation is normally understood as a sequence of two utterances: the analyst gives an interpretation and the patient responds to it. This paper suggests that, in the interpretative sequence, there is also a third utterance where psychoanalytic work takes place. This third interpretative turn involves the analyst’s action after the patient’s response to the interpretation. Using conversation analysis as method in the examination of audio-recorded psychoanalytic sessions, the paper will explicate the psychoanalytic work that gets done in third interpretative turns. Through it, the analyst takes a stance towards the patient’s understandings of the interpretation, which are shown in the patient’s response to the interpretation. The third interpretative turns on one hand ratify and accept the patient’s understandings, but, in addition to that, they also introduce a shift of perspective relative to them. In most cases, the shift of perspective is implicit but sometimes it is made explicit. The shifts of perspective bring to the foreground aspects or implications of the interpretation that were not incorporated in the patient’s response. They recast the description of the patient’s experience by showing new layers or more emotional intensity in it. The results are discussed in the light of Faimberg’s concept of listening to listening and Schlesinger’s concept of follow-up interpretation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Z' = 1 and Z' = 5 structures of quinoxaline are compared. The nature of the intermolecular interactions in the Z' = 5 structure is studied by means of variable-temperature single-crystal X-ray diffraction. The C-H center dot center dot center dot N and pi ... pi it interactions in these structures are of a stabilizing nature. The high Z' structure has the better interactions, whereas the low Z' structure has the better stability. This trade-off is a recurrent theme in molecular crystals and is a manifestation of the distinction between thermodynamically and kinetically favoured crystal forms.