975 resultados para Lamb - confinement
Resumo:
Castrate-resistant prostate cancer (CRPC) is poorly characterized and heterogeneous and while the androgen receptor (AR) is of singular importance, other factors such as c-Myc and the E2F family also play a role in later stage disease. HES6 is a transcription co-factor associated with stem cell characteristics in neural tissue. Here we show that HES6 is up-regulated in aggressive human prostate cancer and drives castration-resistant tumour growth in the absence of ligand binding by enhancing the transcriptional activity of the AR, which is preferentially directed to a regulatory network enriched for transcription factors such as E2F1. In the clinical setting, we have uncovered a HES6-associated signature that predicts poor outcome in prostate cancer, which can be pharmacologically targeted by inhibition of PLK1 with restoration of sensitivity to castration. We have therefore shown for the first time the critical role of HES6 in the development of CRPC and identified its potential in patient-specific therapeutic strategies.
Resumo:
The androgen receptor (AR) regulates prostate cell growth in man, and prostate cancer is the commonest cancer in men in the UK. We present a comprehensive analysis of AR binding sites in human prostate cancer tissues, including castrate-resistant prostate cancer (CRPC). We identified thousands of AR binding sites in CRPC tissue, most of which were not identified in PC cell lines. Many adjacent genes showed AR regulation in xenografts but not in cultured LNCaPs, demonstrating an in-vivo-restricted set of AR-regulated genes. Functional studies support a model of altered signaling in vivo that directs AR binding. We identified a 16 gene signature that outperformed a larger in-vitro-derived signature in clinical data sets, showing the importance of persistent AR signaling in CRPC.
Resumo:
Reinforced concrete (RC) jacketing is a common method to retrofit existing columns with poor structural performance. It can be applied in two different ways: if the continuity of the jacket is ensured, the axial load of the column can be transferred to the jacket, which will be directly loaded; conversely, if no continuity is provided, the jacket induces only confinement action. In both cases the strength and ductility evaluation is rather complex, due to the different physical phenomena included, such as confinement, composite action core-jacket, preload, buckling of longitudinal bars.
Although different theoretical studies have been carried out to calculate the confinement effects, a practical approach to evaluate the flexural capacity and ductility is still missing. The calculation of these quantities is often related to the use of commercial computer programs, taking advantage of numerical methods such as fiber method or finite element method.
This paper presents a simplified approach to calculate the flexural strength and ductility of square RC jacketed sections subjected to axial load and bending moment. In particular the proposed approach is based on the calibration of the stress-block parameters including the confinement effect. Equilibrium equations are determined and buckling of longitudinal bars is modeled with a suitable stress-strain law. Moment-curvature curves are derived with simple calculations. Finally, comparisons are made with numerical analyses carried out with the code OpenSees and with experimental data available in the literature, showing good agreement.
Resumo:
This essay focuses on the lessons of Love’s Labour’s Lost’s pageboy-schoolboy-boy actor, Moth, to examine the production of boyhood in early modern culture. It reads Shakespeare’s boy character alongside John Marston’s schoolboy, Holofernes Pippo, in What You Will to investigate the ways in which school lessons might be deployed to produce aged and gendered identities that complicate traditional understandings of early modern masculinity. Reading the comic staging of lessons in these plays, it will suggest that while the educational system aimed to produce gendered subjects, early modern masculine identities exist as a range of categories on a developmental scale. It will propose that although Moth and Pippo comically expose the limits of many pedagogical methods to produce ‘men’, they demonstrate the ways in which these characters learn to be boys. Finally, it will consider the extent to which this production of early modern age and gender identity in the plays is paralleled by the historical boy actors performing these roles.
Resumo:
BACKGROUND: Understanding the heterogeneous genotypes and phenotypes of prostate cancer is fundamental to improving the way we treat this disease. As yet, there are no validated descriptions of prostate cancer subgroups derived from integrated genomics linked with clinical outcome.
METHODS: In a study of 482 tumour, benign and germline samples from 259 men with primary prostate cancer, we used integrative analysis of copy number alterations (CNA) and array transcriptomics to identify genomic loci that affect expression levels of mRNA in an expression quantitative trait loci (eQTL) approach, to stratify patients into subgroups that we then associated with future clinical behaviour, and compared with either CNA or transcriptomics alone.
FINDINGS: We identified five separate patient subgroups with distinct genomic alterations and expression profiles based on 100 discriminating genes in our separate discovery and validation sets of 125 and 103 men. These subgroups were able to consistently predict biochemical relapse (p = 0.0017 and p = 0.016 respectively) and were further validated in a third cohort with long-term follow-up (p = 0.027). We show the relative contributions of gene expression and copy number data on phenotype, and demonstrate the improved power gained from integrative analyses. We confirm alterations in six genes previously associated with prostate cancer (MAP3K7, MELK, RCBTB2, ELAC2, TPD52, ZBTB4), and also identify 94 genes not previously linked to prostate cancer progression that would not have been detected using either transcript or copy number data alone. We confirm a number of previously published molecular changes associated with high risk disease, including MYC amplification, and NKX3-1, RB1 and PTEN deletions, as well as over-expression of PCA3 and AMACR, and loss of MSMB in tumour tissue. A subset of the 100 genes outperforms established clinical predictors of poor prognosis (PSA, Gleason score), as well as previously published gene signatures (p = 0.0001). We further show how our molecular profiles can be used for the early detection of aggressive cases in a clinical setting, and inform treatment decisions.
INTERPRETATION: For the first time in prostate cancer this study demonstrates the importance of integrated genomic analyses incorporating both benign and tumour tissue data in identifying molecular alterations leading to the generation of robust gene sets that are predictive of clinical outcome in independent patient cohorts.
Resumo:
The androgen receptor (AR) is the dominant growth factor in prostate cancer (PCa). Therefore, understanding how ARs regulate the human transcriptome is of paramount importance. The early effects of castration on human PCa have not previously been studied 27 patients medically castrated with degarelix 7 d before radical prostatectomy. We used mass spectrometry, immunohistochemistry, and gene expression array (validated by reverse transcription-polymerase chain reaction) to compare resected tumour with matched, controlled, untreated PCa tissue. All patients had levels of serum androgen, with reduced levels of intraprostatic androgen at prostatectomy. We observed differential expression of known androgen-regulated genes (TMPRSS2, KLK3, CAMKK2, FKBP5). We identified 749 genes downregulated and 908 genes upregulated following castration. AR regulation of α-methylacyl-CoA racemase expression and three other genes (FAM129A, RAB27A, and KIAA0101) was confirmed. Upregulation of oestrogen receptor 1 (ESR1) expression was observed in malignant epithelia and was associated with differential expression of ESR1-regulated genes and correlated with proliferation (Ki-67 expression).
PATIENT SUMMARY: This first-in-man study defines the rapid gene expression changes taking place in prostate cancer (PCa) following castration. Expression levels of the genes that the androgen receptor regulates are predictive of treatment outcome. Upregulation of oestrogen receptor 1 is a mechanism by which PCa cells may survive despite castration.
Resumo:
The current model of mid-latitude late Quaternary terrace sequences, is that they are uplift-driven but climatically controlled terrace staircases, relating to both regional-scale crustal and tectonic factors, and palaeohydrological variations forced by quasi-cyclic climatic conditions in the 100 K world (post Mid Pleistocene Transition). This model appears to hold for the majority of the river valleys draining into the English Channel which exhibit 8–15 terrace levels over approximately 60–100 m of altitudinal elevation. However, one valley, the Axe, has only one major morphological terrace and has long-been regarded as anomalous. This paper uses both conventional and novel stratigraphical methods (digital granulometry and terrestrial laser scanning) to show that this terrace is a stacked sedimentary sequence of 20–30 m thickness with a quasi-continuous (i.e. with hiatuses) pulsed, record of fluvial and periglacial sedimentation over at least the last 300–400 K yrs as determined principally by OSL dating of the upper two thirds of the sequence. Since uplift has been regional, there is no evidence of anomalous neotectonics, and climatic history must be comparable to the adjacent catchments (both of which have staircase sequences) a catchment-specific mechanism is required. The Axe is the only valley in North West Europe incised entirely into the near-horizontally bedded chert (crypto-crystalline quartz) and sand-rich Lower Cretaceous rocks creating a buried valley. Mapping of the valley slopes has identified many large landslide scars associated with past and present springs. It is proposed that these are thaw-slump scars and represent large hill-slope failures caused by Vauclausian water pressures and hydraulic fracturing of the chert during rapid permafrost melting. A simple 1D model of this thermokarstic process is used to explore this mechanism, and it is proposed that the resultant anomalously high input of chert and sand into the valley during terminations caused pulsed aggradation until the last termination. It is also proposed that interglacial and interstadial incision may have been prevented by the over-sized and interlocking nature of the sub-angular chert clasts until the Lateglacial when confinement of the river overcame this immobility threshold. One result of this hydrogeologically mediated valley evolution was to provide a sequence of proximal Palaeolithic archaeology over two MIS cycles. This study demonstrates that uplift tectonics and climate alone do not fully determine Quaternary valley evolution and that lithological and hydrogeological conditions are a fundamental cause of variation in terrestrial Quaternary records and landform evolution.
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BACKGROUND: The androgen receptor (AR) is a major drug target in prostate cancer (PCa). We profiled the AR-regulated kinome to identify clinically relevant and druggable effectors of AR signaling.
METHODS: Using genome-wide approaches, we interrogated all AR regulated kinases. Among these, choline kinase alpha (CHKA) expression was evaluated in benign (n = 195), prostatic intraepithelial neoplasia (PIN) (n = 153) and prostate cancer (PCa) lesions (n = 359). We interrogated how CHKA regulates AR signaling using biochemical assays and investigated androgen regulation of CHKA expression in men with PCa, both untreated (n = 20) and treated with an androgen biosynthesis inhibitor degarelix (n = 27). We studied the effect of CHKA inhibition on the PCa transcriptome using RNA sequencing and tested the effect of CHKA inhibition on cell growth, clonogenic survival and invasion. Tumor xenografts (n = 6 per group) were generated in mice using genetically engineered prostate cancer cells with inducible CHKA knockdown. Data were analyzed with χ(2) tests, Cox regression analysis, and Kaplan-Meier methods. All statistical tests were two-sided.
RESULTS: CHKA expression was shown to be androgen regulated in cell lines, xenografts, and human tissue (log fold change from 6.75 to 6.59, P = .002) and was positively associated with tumor stage. CHKA binds directly to the ligand-binding domain (LBD) of AR, enhancing its stability. As such, CHKA is the first kinase identified as an AR chaperone. Inhibition of CHKA repressed the AR transcriptional program including pathways enriched for regulation of protein folding, decreased AR protein levels, and inhibited the growth of PCa cell lines, human PCa explants, and tumor xenografts.
CONCLUSIONS: CHKA can act as an AR chaperone, providing, to our knowledge, the first evidence for kinases as molecular chaperones, making CHKA both a marker of tumor progression and a potential therapeutic target for PCa.
Resumo:
One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of 90Sr insertion and decay in C-S-H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that 90Sr is stable when it substitutes the Ca2+ ions in C-S-H, and so is its daughter nucleus 90Y after β-decay. Interestingly, 90Zr, daughter of 90Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for 90Sr storage.
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This work investigated the differences in the reactivity of Sarda (primiparous n= 18, multiparous n= 17) and Dorset (multiparous n= 8) breeds of sheep and their singleton lambs to two challenging test situations involving a mother-lamb partial separation test and an isolation test. Non-parametric analysis used single behavioural variables and fear scores to evaluate the effect of parity, sex of lambs, and the association between mother-lamb behaviour. Amongst ewes, Dorset were characterised by a more calm temperament while Sarda (especially primiparous ewes) were more active in their response to challenge (i.e. more attempts to escape). As with their dams, lambs reflected to a certain extent this divergence and overall during isolation lamb fear score was on average significantly higher than dams. Correlations between measures of behavioural reactivity across tests were carried out to search for predictive measures of fear. A very strong correlation emerged linking vocalisation to locomotor activity. Vocalisation could be a good candidate as predictor factor of an active reaction of sheep to a fearful situation.
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Molecular characterization of genome-wide association study (GWAS) loci can uncover key genes and biological mechanisms underpinning complex traits and diseases. Here we present deep, high-throughput characterization of gene regulatory mechanisms underlying prostate cancer risk loci. Our methodology integrates data from 295 prostate cancer chromatin immunoprecipitation and sequencing experiments with genotype and gene expression data from 602 prostate tumor samples. The analysis identifies new gene regulatory mechanisms affected by risk locus SNPs, including widespread disruption of ternary androgen receptor (AR)-FOXA1 and AR-HOXB13 complexes and competitive binding mechanisms. We identify 57 expression quantitative trait loci at 35 risk loci, which we validate through analysis of allele-specific expression. We further validate predicted regulatory SNPs and target genes in prostate cancer cell line models. Finally, our integrated analysis can be accessed through an interactive visualization tool. This analysis elucidates how genome sequence variation affects disease predisposition via gene regulatory mechanisms and identifies relevant genes for downstream biomarker and drug development.
Resumo:
Reinforced concrete (RC) jacketing is a common method for retrofitting existing columns with poor structural performance. It can be applied in two different ways: if the continuity of the jacket is ensured, the axial load of the column can be transferred to the jacket, which will be directly loaded; conversely, if no continuity is provided, the jacket will induce only confinement action. In both cases the strength and ductility evaluation is rather complex, due to the different physical phenomena included, such as confinement, core-jacket composite action, preload and buckling of longitudinal bars.
Although different theoretical studies have been carried out to calculate the confinement effects, a practical approach to evaluate the flexural capacity and ductility is still missing. The calculation of these quantities is often related to the use of commercial software, taking advantage of numerical methods such as fibre method or finite element method.
This paper presents a simplified approach to calculate the flexural strength and ductility of square RC jacketed sections subjected to axial load and bending moment. In particular the proposed approach is based on the calibration of the stress-block parameters including the confinement effect. Equilibrium equations are determined and buckling of longitudinal bars is modelled with a suitable stress-strain law. Moment-curvature curves are derived with simple calculations. Finally, comparisons are made with numerical analyses carried out with the code OpenSees and with experimental data available in the literature, showing good agreement.
Resumo:
Women of letters writes a new history of English women's intellectual worlds using their private letters as evidence of hidden networks of creative exchange. The book argues that many women of this period engaged with a life of the mind and demonstrates the dynamic role letter-writing played in the development of ideas. Until now, it has been assumed that women's intellectual opportunities were curtailed by their confinement in the home. This book illuminates the household as a vibrant site of intellectual thought and expression. Amidst the catalogue of day-to-day news in women's letters are sections dedicated to the discussion of books, plays and ideas. Through these personal epistles, Women of letters offers a fresh interpretation of intellectual life in the late seventeenth and early eighteenth centuries, one that champions the ephemeral and the fleeting in order to rediscover women's lives and minds.
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Num mundo cada vez mais industrializado e consumista, com assimetrias territoriais várias, a defesa dos valores ambientais assume uma progressiva importância, uma vez que a qualidade de vida passa também pela qualidade ambiental. Como os produtos gerados pelo consumo devem ter o confinamento correto em função das suas diversas componentes, a gestão do processo de deposição, recolha e transporte de RSU, fica mais complexa, à medida que a população e a área se diversifica e expande, como acontece em alguns territórios rurais, agravando os custos e os impactos ambientais induzidos, se não for equacionada uma solução simultaneamente eficaz e eficiente. Paralelamente urge a satisfação dos residentes e dos restantes utilizadores enquanto usuários desses territórios. Por este motivo, nos últimos anos, as autarquias têm vindo a estudar essas soluções nas suas áreas de jurisdição, tentando com as ações realizadas, respeitar não só os critérios de proteção ambiental, mas também as necessidades das pessoas. Neste trabalho apresentam-se algumas variáveis identificadas, como resultados de um estudo de caso aplicado a um município rural, Anadia, onde se evidencia a ausência de sensibilização e a carência de meios e processos que podem comprometer as metas ambientais e sociais desejadas. In a world, progressively more industrialized and consumer, with several territorial disparities, the protection of environmental values assumes an increasingly importance, since the quality of life also involves environmental quality. As the products generated by the consumption must have a correct confinement in its various components, the management of the deposition process, collection and transportation of municipal solid waste, is more complex, as the population and the area expand, as happens in some rural territories, increasing the cost and environmental impacts induced, if not equated a solution both effective and efficient. At the same time it is very important to increase the satisfaction of residents, visitors and tourists visiting these areas. For this reason, in the last years, the municipalities have been studying these solutions in their areas of jurisdiction. That is why they try to respect not only the criteria of environmental protection, but also the needs of people and fulfilled actions whose variables we shall try to present as a case study applied to a rural municipality, Anadia, where we show up that the absence of awareness and the lack of means and processes can compromise the desired environmental and social goals
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Esta tese relata estudos de síntese, caracterização da estrutura e das propriedades de fotoluminescência e aplicações de nanotubos e nanobastonetes de óxidos de lantanídeos em pontas para microscopia de força atómica, catálise heterogénea e compósitos de base polimérica. Há um interesse crescente em compreender como o confinamento quântico decorrente da redução do tamanho de partícula pode influenciar a eficiência da luminescência, a dinâmica dos estados excitados, a transferência de energia e os efeitos de termalização de nanoluminóforos. Em nanocristais dopados com lantanídeos (Ln3+), e apesar da localização dos estados 4f, ocorrem efeitos de confinamento quântico via interacção com os modos vibracionais da rede. Em particular, a termalização anómala, descrita para uma variedade de nanocristais dopados com Ln3+, tem sido atribuída à ausência de modos vibracionais de menor frequência. Este nanoconfinamento pode ter impacto na dinâmica da luminescência, bem como na transferência de energia mediada por modos vibracionais e processos de upconversion. Nesta tese, relata-se o estudo deste efeito em nanotubos de Gd2O3:Eu3+. A influência de parâmetros como a concentração de európio e as condições de calcinação também foi investigada. Algumas aplicações destes óxidos de lantanídeos também foram exploradas, nomeadamente a modificação de pontas usadas em microscopia de força atómica com nanobastonetes de Gd2O3:Eu3+, lograda através de dielectroforese, técnica que não degrada a emissão de luz (rendimento quântico 0.47). As pontas modificadas são estáveis sob condições de trabalho, podendo ser aplicadas, por exemplo, em microscopia óptica de varrimento de campo próximo (SNOM). A oxidação em fase líquida do etilbenzendo foi investigada usando como catalisador nanotubos de CeO2, em presença dos oxidantes hidroperóxido de t-butilo e H2O2, e do solvente acetonitrilo, e temperaturas entre 55 e 105 ºC. Nanobastonetes de Gd2O3:Eu3+ recobertos com sílica foram preparados pelo método sol-gel. Esta cobertura resultou num aumento, quer do rendimento quântico de emissão, de 0.51 para 0.86 (excitação a 255 nm), quer dos tempos de vida,de 1.43 para 1.80 ms (excitação a 394.4 nm). A superfície dos nanotubos cobertos com sílica foi modificada com o agente de acoplamento metacrilato de 3-(trimetoxissilil)propilo que permitiu a preparação de compósitos através da subsequente polimerização in-situ do estireno por técnicas de miniemulsão e solução. ABSTRACT: This thesis reports on the synthesis, characterisation of the structure and photoluminescence properties, and applications of nanotubes and nanorods of lanthanides oxides in atomic force microscopy tips, heterogeneous catalysis and polymer-base composites. There is a growing interest in understanding how size-dependent quantum confinement affects the photoluminescence efficiency, excited-state dynamics, energy-transfer and thermalisation phenomena in nanophosphors. For lanthanide (Ln3+)-doped nanocrystals, and despite the localisation of the 4f states, confinement effects are induced mostly via electron-phonon interactions. In particular, the anomalous thermalisation reported for a handful of Ln3+-doped nanocrystals has been rationalised by the absence of lowfrequency phonon modes. This nanoconfinement may further impact on the Ln3+ luminescence dynamics, such as phonon-assisted energy transfer or upconversion processes. Here, this effect is investigated in Gd2O3:Eu3+ nanotubes. The influence of parameters such as europium concentration and calcination procedure is also studied. Some applications of these lanthanides oxides have been explored, for instance the modification of atomic force microscopy tips with photoluminescent Gd2O3:Eu3+ nanorods, using dielectrophoresis, a technique which preserves the red emission of the nanorods (quantum yield 0.47). The modified tips are stable under working conditions and may find applications in scanning near-field optical microscopy. The liquid-phase oxidation of ethylbenzene over CeO2 nanotubes has been investigated, using tert-butyl-hydroperoxide and H2O2 as the oxidising agents, and acetonitrile as the solvent, in the range 55-105 ºC. Gd2O3:Eu3+ nanorods have been coated with silica via a sol-gel approach. The silica coating increases both, the Eu3+ absolute emission quantum yields from 0.51 to 0.86 (255 nm excitation), and decay times from 1.43 to 1.80 ms (394.4 nm excitation). The silica coating was modified with 3- (trimethoxysilyl) propyl methacrylate and, subsequently, composites have been prepared by in-situ radical polymerisation of styrene via miniemulsion and solution routes.