993 resultados para Motifs
Resumo:
Filmmediet idag är den mest populära formen av masskultur. Med sin världstäckande genomslagskraft och sitt stereotypa porträtterande av verklighet, påverkar filmen världsåskådningen för människor runtom i världen. Ett brinnande ämne i amerikansk film har alltid varit Ryssland, på grund av de politiska motsättningarna och den historiska rivaliteten med USA. Studiens syfte är att undersöka hur Ryssland porträtteras i amerikanska filmer från perioden för presidenterna Dmitrij Medvedevs respektive Barack Obamas första mandatperiod. Frågeställningen för uppsatsen är: hur ser stereotypa föreställningar om Ryssland ut i amerikansk film 2008-2011? Trettiotal filmer med ryska motiv valdes ut för undersökningen och analyserades utifrån de visuella och sociala aspekterna. Resultatet visar på att det förekommer tre skikt av stereotyper om Ryssland: de eviga, som har existerat i hundratals år och spridits av resenärer; stereotyper från epoken för det kalla kriget; och stereotyper om det moderna Ryssland inspirerade av medias nyhetsrapporteringar.
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The aim of this thematic study is to examine how the water motif is used in Marguerite Duras’s literary work. The study shows that water has multiple functions in these texts: it is linked to major themes and creates an enigmatic atmosphere by its association with the unknown, the inexplicable and the unconscious. The strong presence of water in Duras’s texts is striking. References to the water element can be found in several titles throughout her career, from early works such as Un barrage contre le Pacifique (1950) to La mer écrite (1996), published just after her death. Almost all of her fiction take place near water – and the rain or the sound of waves serve as leitmotifs in specific novels. The water motif can play a metonymic as well as a metaphoric role in the texts and it sometimes takes on human or animalistic characteristics (Chapter 4). Several emblematic Durassian characters (e.g. the beggar-woman, Anne-Marie Stretter and Lol V. Stein) have a close relationship to water (Chapter 5). The water motif is linked to many major Durassian themes, and illustrates themes with positive connotations, for example, creation, fecundity, maternity, liberty and desire, as well as themes with negative connotations such as destruction and death (Chapter 6). A close reading of three novels, La vie tranquille (1944), L’après-midi de Monsieur Andesmas (1962) and La maladie de la mort (1982), shows that the realism of the first novel is replaced by intriguing evocations of the sea and the pond in the second text, motifs which resist straightforward interpretation. The enigmatic feeling persists in the last novel, in which the sea illustrates the overall sombre mood of the story (Chapter 7). Finally, the role of the water element in psychoanalytic theory is discussed (Chapter 8), and a parallel is drawn between the Jungian concept of the mother archetype and the water motif in Duras’s texts. The suggestion is made in this last chapter that water is used to illustrate an oriental influence (Taoist or Buddhist) of some of the female characters in Duras’s work.
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Metals are essential for the normal functioning of living organisms. Their uses in biological systems are varied, but are frequently associated with sites of critical protein function, such as zinc finger motifs and electron or oxygen carriers. These functions only require essential metals in minute amounts, hence they are termed trace metals. Other metals are, however, less beneficial, owing to their ability to promote a wide variety of eleterious health effects, including cancer. Metals such as arsenic, for example, an produce a variety of diseases ranging from keratosis of the palms and feet to cancers in multiple target organs. The nature and type of metal-induced pathologies appear to be dependent on the concentration, speciation, and length of exposure. Unfortunately, human contact with metals is an inescapable consequence of human life, with exposures occurring from both occupational and environmental sources. A uniform mechanism of action for all harmful metals is unlikely, if not implausible, given the diverse chemical properties of each metal. In this chapter we will review the mechanisms of carcinogenesis of arsenic, cadmium, chromium, and nickel, the four known carcinogenic metals that are best understood. The key areas of speciation, bioavailability, and mechanisms of action are discussed with particular reference to the role of metals in alteration of gene expression and maintenance of genomic integrity.
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Excess copper is effluxed from mammalian cells by the Menkes or Wilson P-type ATPases (MNK and WND, respectively). MNK and WND have six metal binding sites (MBSs) containing a CXXC motif within their N-terminal cytoplasmic region. Evidence suggests that copper is delivered to the ATPases by Atox1, one of three cytoplasmic copper chaperones. Attempts to monitor a direct Atox1-MNK interaction and to determine kinetic parameters have not been successful. Here we investigated interactions of Atox1 with wild-type and mutated pairs of the MBSs of MNK using two different methods: yeast two-hybrid analysis and real-time surface plasmon resonance (SPR). A copper-dependent interaction of Atox1 with the MBSs of MNK was observed by both approaches. Cys to Ser mutations of conserved CXXC motifs affected the binding of Atox1 underlining the essentiality of Cys residues for the copper-induced interaction. Although the yeast two-hybrid assay failed to show an interaction of Atox1 with MBS5/6, SPR analysis clearly demonstrated a copper-dependent binding with all six MBSs highlighting the power and sensitivity of SPR as compared with other, more indirect methods like the yeast two-hybrid system. Binding constants for copper-dependent chaperone-MBS interactions were determined to be 10–5-10–6 M for all the MBSs representing relatively low affinity binding events. The interaction of Atox1 with pairs of the MBSs was non-cooperative. Therefore, a functional difference of the MBSs in the MNK N terminus cannot be attributed to cooperativity effects or varying affinities of the copper chaperone Atox1 with the MBSs.
A computational approach to the reconstruction of surface geometry from early temple superstructures
Resumo:
Recovering the control or implicit geometry underlying temple architecture requires bringing together fragments of evidence from field measurements, relating these to mathematical and geometric descriptions in canonical texts and proposing "best-fit" constructive models. While scholars in the field have traditionally used manual methods, the innovative application of niche computational techniques can help extend the study of artefact geometry. This paper demonstrates the application of a hybrid computational approach to the problem of recovering the surface geometry of early temple superstructures. The approach combines field measurements of temples, close-range architectural photogrammetry, rule-based generation and parametric modelling. The computing of surface geometry comprises a rule-based global model governing the overall form of the superstructure, several local models for individual motifs using photogrammetry and an intermediate geometry model that combines the two. To explain the technique and the different models, the paper examines an illustrative example of surface geometry reconstruction based on studies undertaken on a tenth century stone superstructure from western India. The example demonstrates that a combination of computational methods yields sophisticated models of the constructive geometry underlying temple form and that these digital artefacts can form the basis for in depth comparative analysis of temples, arising out of similar techniques, spread over geography, culture and time.
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C-type natriuretic peptide (CNP) is a crucial osmoregulatory hormone in elasmobranchs, participating in salt secretion and drinking. In contrast to teleosts and tetrapods in which the NP family is composed of a group of structurally related peptides, we have shown that CNP is the sole NP in sharks. In the present study, CNP cDNAs were cloned from four species of batoids, another group of elasmobranchs. The cloned batoid CNP precursors contained a plausible mature peptide of 22 amino acid residues that is identical to most shark CNP-22s, but five successive amino acids were consistently deleted in the prosegment compared with shark precursors, supporting the diphyletic classification of sharks and rays. In addition, molecular phylogenetic trees of CNP precursors were consistent with a diphyletic interpretation. Except for the deletion, the nucleotide and deduced amino acid sequences of the CNP cDNAs are extremely well-conserved among all elasmobranch species, even between sharks and rays. Surprisingly, high conservation is evident not only for the coding region, but also for the untranslated regions. It is most likely that the high conservation is due to the low nucleotide substitution rate in the elasmobranch genome, and high selection pressure. The 3′-untranslated region of the elasmobranch CNP cDNAs contained three to six repeats of the ATTTA motif that is associated with the regulation of mRNA stability and translation efficiency. Alternative polyadenylation sites were also found; the long 3′-untranslated region contains a core of ATTTA motifs while the short form has only one or no ATTTA motif, indicating that the post-transcriptional modification of mRNA is important for regulation of CNP synthesis. These characteristics in the 3′-untranslated region were conserved among all elasmobranch CNP cDNAs. Since CNP has been implicated as a fast-acting hormone to facilitate salt secretion from the rectal gland, the conserved 3′-untranslated region most likely contributes to rapid regulation of CNP synthesis in elasmobranchs in response to acute changes in internal and external environments.
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In this article, we explore the role of the C-terminus (V5 domain) of PKCvar epsilon plays in the catalytic competence of the kinase using serial truncations followed by immune-complex kinase assays. Surprisingly, removal of the last seven amino acid residues at the C-terminus of PKCvar epsilon resulted in a PKCvar epsilon-Δ731 mutant with greatly reduced intrinsic catalytic activity while truncation of eight amino acid residues at the C-terminus resulted in a catalytically inactive PKCvar epsilon mutant. Computer modeling and molecular dynamics simulations showed that the last seven and/or eight amino acid residues of PKCvar epsilon were involved in interactions with residues in the catalytic core. Further truncation analyses revealed that the hydrophobic phosphorylation motif was dispensable for the physical interaction between PKCvar epsilon and 3-phosphoinositide-dependent kinase-1 (PDK-1) as the PKCvar epsilon mutant lacking both the turn and the hydrophobic motifs could still be co-immunoprecipitated with PDK-1. These results provide fresh insights into the biochemical and structural basis underlying the isozyme-specific regulation of PKC and suggest that the very C-termini of PKCs constitute a promising new target for the development of novel isozyme-specific inhibitors of PKC.
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In an attempt to improve automated gene prediction in the untranslated region of a gene, we completed an in-depth analysis of the minimum free energy for 8,689 sub-genetic DNA sequences. We expanded Zhang's classification model and classified each sub-genetic sequence into one of 27 possible motifs. We calculated the minimum free energy for each motif to explore statistical features that correlate to biologically relevant sub-genetic sequences. If biologically relevant sub-genetic sequences fall into distinct free energy quanta it may be possible to characterize a motif based on its minimum free energy. Proper characterization of motifs can lead to greater understanding in automated genefinding, gene variability and the role DNA structure plays in gene network regulation.
Our analysis determined: (1) the average free energy value for exons, introns and other biologically relevant sub-genetic sequences, (2) that these subsequences do not exist in distinct energy quanta, (3) that introns exist however in a tightly coupled average minimum free energy quantum compared to all other biologically relevant sub-genetic sequence types, (4) that single exon genes demonstrate a higher stability than exons which span the entire coding sequence as part of a multi-exon gene and (5) that all motif types contain a free energy global minimum at approximately nucleotide position 1,000 before reaching a plateau. These results should be relevant to the biochemist and bioinformatician seeking to understand the relationship between sub-genetic sequences and the information behind them.
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There are no adequate vaccines against some of the new or reemerged infectious scourges such as HIV and TB. They may require strong and enduring cell-mediated immunity to be elicited. This is quite a task, as the only known basis of protection by current commercial vaccines is antibody. As DNA or RNA vaccines may induce both cell-mediated and humoral immunity, great interest has been shown in them. However, doubt remains whether their efficacy will suffice for their clinical realization. We look at the various tactics to increase the potency of nucleic acid vaccines and divided them broadly under those affecting delivery and those affecting immune induction. For delivery, we have considered ways of improving uptake and the use of bacterial, replicon or viral vectors. For immune induction, we considered aspects of immunostimulatory CpG motifs, coinjection of cytokines or costimulators and alterations of the antigen, its cellular localization and its anatomical localization including the use of ligand-targeting to lymphoid tissue. We also thought that mucosal application of DNA deserved a separate section. In this review, we have taken the liberty to discuss these enhancement methods, whenever possible, in the context of the underlying mechanisms that might argue for or against these strategies.
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Monomeric tellurides 4-RC6H4(SB)Te [SB = 2-(4,4'-N02C6H4CH=NC6H3-Me); R = H, 1a; Me,1b; OMe, 1c], which incidentally represent the first example of a telluride with 1,4-Te···N intramolecular interaction, have been prepared and characterized by solution and solid-state 125Te NMR, 13C NMR and X-ray crystallography. Interplay of weak C-H···O and C-H-··π{ interactions in the crystal lattice of 1b and1c are responsible for the formation of supramolecular motifs. These tellurides undergo expected oxidative addition reactions with halogens and interhalogens and also interact coordinatively with mercury(II) halides to give 1:2 complexes, HgX2[4-RC6H4(SB)Te]2 (X = CI, R = H, 2a; Me, 2b; OMe, 2c and X = Br, R = H, 3a; Me, 3b; and OMe, 3c) with no sign of Te-C bond cleavage, as has been reported for some 1,5-Te·· ·N(O) intramolecularly bonded tellurides. The complexes 2a and 3c are the first structurally characterized monomeric 1:2 adducts of mercury(II) halides with Te ligands. The 1,4-Te···N intramolecular interactions in the solid-state are retained in the complexes highlighting simultaneously the Lewis acid and base character of the Te(lI) atom. Packing of molecules in the crystal lattice of 2a
and 3c reveals that non-covalent C-H· . ·Cl/Br interactions involving metal-bound halogen atoms possess significant directionality and in
combination with coordinative covalent interactions may be of potential use in creating inorganic supramolecular synthons.
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This review article focuses primarily on the work carried in our laboratories over the last few years using luminescent and colorimetric sensors, where the anion recognition occurs through hydrogen bonding in organic or aqueous solvents. This review begins with the story of the discovery of fluorescent photoinduced electron transfer (PET) sensors for anions using charged neutral urea or thiourea receptors where both fluorescent and NMR spectroscopic methods monitored anion recognition. This work led to the development of dual luminescent and colorimetric anion sensors based on the use of the ICT based naphthalimide chromophore, where ions such as fluoride gave rise to changes in both the fluorescence and the absorption spectra of the sensors, but at different concentrations. Here, the former changes were due to hydrogen bonding interactions, whereas the latter was due to the deprotonation of acidic protons, giving rise to the formation of the bifluoride anion (HF2−). Modification of the 4-amino-l,8-naphthalimide moiety has facilitated the formation of colorimetric anion sensors that work both in organic or aqueous solutions. Such charge neutral receptor motifs have also been incorporated into organic scaffolds with norbomyl and calixarene backbones, which have enabled us to produce anion directed self-assembled structures.
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The application of computational techniques to the analysis of heritage artifacts enables scholars to bring together diverse fragments of surviving evidence, construe "best-fit" strategies and unearth implicit or hidden relationships. This paper reports a hybrid approach for recovering the surface geometry of temples. The approach combines physical measurements, architectural photogrammetry and generative rules to create a parametric model of the surface. The computing of surface geometry is broken into three parts, a global model governing the overall form of the superstructure, local models governing the geometry of individual motifs and finally the global and local models are combined into a single geometry. In this paper, the technique for recovering surface geometry is applied to a tenth century stone superstructure: the temple of Ranakdevi at Wadhwan in Western India. The global model of the superstructure and the local model of one individual motif are presented.
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PRK2/PKNγ is a Rho effector and a member of the protein kinase C superfamily of serine/threonine kinases. Here, we explore the structure–function relationship between various motifs in the C-terminal half of PRK2 and its kinase activity and regulation. We report that two threonine residues at conserved phosphoacceptor position in the activation loop and the turn motif are essential for the catalytic activity of PRK2, but the phosphomimetic Asp-978 at hydrophobic motif is dispensable for kinase catalytic competence. Moreover, the PRK2-Δ958 mutant with the turn motif truncated still interacts with 3-phosphoinositide-dependent kinase-1 (PDK-1). Thus, both the intact hydrophobic motif and the turn motif in PRK2 are dispensable for the binding of PDK-1. We also found that while the last seven amino acid residues at the C-terminus of PRK2 are not required for the activation of the kinase by RhoA in vitro, however, the extreme C-terminal segment is critical for the full activation of PRK2 by RhoA in cells in a GTP-dependent manner. Our data suggest that the extreme C-terminus of PRK2 may represent a potential drug target for effector-specific pharmacological intervention of Rho-medicated biological processes.
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Human telomerase reverse transcriptase (hTERT) underlies cancer cell immortalization, and the expression of hTERT is regulated strictly at the gene transcription. Here, we report that transcription factor Ets2 is required for hTERT gene expression and breast cancer cell proliferation. Silencing Ets2 induces a decrease of hTERT gene expression and increase in human breast cancer cell death. Reconstitution with recombinant hTERT rescues the apoptosis induced by Ets2 depression. In vitro and in vivo analyses show that Ets2 binds to the EtsA and EtsB DNA motifs on the hTERT gene promoter. Mutation of either Ets2 binding site reduces the hTERT promoter transcriptional activity. Moreover, Ets2 forms a complex with c-Myc as demonstrated by co-immunoprecipitation and glutathione S-transferase pulldown assays. Immunological depletion of Ets2, or mutation of the EtsA DNA motif, disables c-Myc binding to the E-box, whereas removal of c-Myc or mutation of the E-box also compromises Ets2 binding to EtsA. Thus, hTERT gene expression is maintained by a mechanism involving Ets2 interactions with the c-Myc transcription factor and the hTERT gene promoter, a protein-DNA complex critical for hTERT gene expression and breast cancer cell proliferation.
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This thesis is submitted within the discipline of Women's Studies. It attempts to assess the life of women in a tribal society at the brink of dissolution. Wales at the eve of and during the first century of the Norman occupation is representative of such a society and historians admit that what little we know of its social conditions can be gleaned from the pages of the narrative prose collection The Mabinogion. Consequently this study uses an interdisciplinary approach. Eight stories from The Mabinogion collection have been studied: The Four Branches, comprising Pwyll Prince of Dyfed, Branwen Daughter of Llyr, Manawydan Son of Llyr and Math Son of Mathonwwy; the story of Culhwch and Olwen and the Three Romances, comprising The Lady of the Fountain, Peredur Son of Efrawg and Gereint Son of Erbin. The Four Branches are a fourfold narrative held together by the figure of Sovereignty (formerly the Celtic goddess of the land), her chosen consort and her son. The protagonists are now represented as superhuman men and women and encoded in their lifestories are the rules for gender-related 'right' behaviour of princes and their spouses. The Three Romances still show the same constellation, but the figures of Sovereignty and her consort have been replaced by the Knight and his Lady with considerable loss of behavioural certainty for both genders. The romances are also indicative of growing economic insecurity. Culhwch and Olwen has been included for contrast and for its richness in folkloric motifs. Apart from studying the gender-roles in leading families at the time, the thesis advances the theory that The Four Branches may have been the work of a Welsh noblewoman - a theory based on the inherent knowledge of Welsh pre-Christian dynastic traditions, legal and political practices and the realities of women's lives at the time. The study also shows that the status of women and their legal rights in pre-Norman Wales were much more restricted and cannot generally be compared with that of women in England or Ireland.