18,688 research outputs found

    Literature review on pickling inhibitors and cadmium electroplating processes

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    Because introduction of hydrogen during bright-cadmium electroplating of high strength steels causes hydrogen-stress cracking, a program was undertaken to evaluate various processes and materials. Report describes effectiveness of inhibitors for reducing hydrogen absorption by steels

    A review of the literature on pickling inhibitors and cadmium electroplating processes to minimize hydrogen absorption by ultrahigh-strength steels

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    Literature review on pickling inhibitors and cadmium electroplating processes to minimize hydrogen absorption by ultrahigh strength steel

    Review of literature on hydrogen embrittlement

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    Hydrogen embrittlement in high strength iron-base and nickel-base alloys and titaniu

    A study of hydrogen embrittlement of various alloys Annual summary report, 24 Jun. 1965 - 23 Jun. 1966

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    Hydrogen embrittlement of alloy cathodically charged and notched tensile metal

    A theoretical investigation of the effect of proliferation & adhesion on monoclonal conversion in the colonic crypt

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    The surface epithelium lining the intestinal tract renews itself rapidly by a coordinated programme of cell proliferation, migration and differentiation events that is initiated in the crypts of Lieberkühn. It is generally believed that colorectal cancer arises due to mutations that disrupt the normal cellular dynamics of the crypts. Using a spatially structured cell-based model of a colonic crypt, we investigate the likelihood that the progeny of a mutated cell will dominate, or be sloughed out of, a crypt. Our approach is to perform multiple simulations, varying the spatial location of the initial mutation, and the proliferative and adhesive properties of the mutant cells, to obtain statistical distributions for the probability of their domination. Our simulations lead us to make a number of predictions. The process of monoclonal conversion always occurs, and does not require that the cell which initially gave rise to the population remains in the crypt. Mutations occurring more than one to two cells from the base of the crypt are unlikely to become the dominant clone. The probability of a mutant clone persisting in the crypt is sensitive to dysregulation of adhesion. By comparing simulation results with those from a simple one-dimensional stochastic model of population dynamics at the base of the crypt, we infer that this sensitivity is due to direct competition between wild-type and mutant cells at the base of the crypt. We also predict that increases in the extent of the spatial domain in which the mutant cells proliferate can give rise to counter-intuitive, non-linear changes to the probability of their fixation, due to effects that cannot be captured in simpler models

    Thermo-acoustic wave propagation and reflection near the liquid-gas critical point

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    We study the thermo-acoustic wave propagation and reflection near the liquid-gas critical point. Specifically, we perform a numerical investigation of the acoustic responses in a near-critical fluid to thermal perturbations based on the same setup of a recent ultrasensitive interferometry measurement in CO2 [Y. Miura et al. Phys. Rev. E 74, 010101(R) (2006)]. The numerical results agree well with the experimental data. New features regarding the reflection pattern of thermo-acoustic waves near the critical point under pulse perturbations are revealed by the proper inclusion of the critically diverging bulk viscosity.Comment: 14 pages, 4 figures, Accepted by PRE (Rapid Communication

    Implementing vertex dynamics models of cell populations in biology within a consistent computational framework

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    The dynamic behaviour of epithelial cell sheets plays a central role during development, growth, disease and wound healing. These processes occur as a result of cell adhesion, migration, division, differentiation and death, and involve multiple processes acting at the cellular and molecular level. Computational models offer a useful means by which to investigate and test hypotheses about these processes, and have played a key role in the study of cell–cell interactions. However, the necessarily complex nature of such models means that it is difficult to make accurate comparison between different models, since it is often impossible to distinguish between differences in behaviour that are due to the underlying model assumptions, and those due to differences in the in silico implementation of the model. In this work, an approach is described for the implementation of vertex dynamics models, a discrete approach that represents each cell by a polygon (or polyhedron) whose vertices may move in response to forces. The implementation is undertaken in a consistent manner within a single open source computational framework, Chaste, which comprises fully tested, industrial-grade software that has been developed using an agile approach. This framework allows one to easily change assumptions regarding force generation and cell rearrangement processes within these models. The versatility and generality of this framework is illustrated using a number of biological examples. In each case we provide full details of all technical aspects of our model implementations, and in some cases provide extensions to make the models more generally applicable

    A theoretical investigation of the effect of proliferation and\ud adhesion on monoclonal conversion in the colonic crypt

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    Colorectal cancers are initiated by the accumulation of mutations in the colonic epithelium. Using a spatially structured cell-based model of a colonic crypt, we investigate the likelihood that the progeny of a mutated cell will dominate, or be sloughed out of, a crypt. Our approach is to perform multiple simulations, varying the spatial location of the initial mutation, and its proliferative and adhesive properties, to obtain statistical distributions for the probability of domination. Our simulations lead us to make a number of predictions. The process of monoclonal conversion always occurs, and does not require that the cell which initially gave rise to the population remains in the crypt. Mutations occurring more than one to two cells from the base of the crypt are unlikely to become the dominant clone. The probability of a mutant clone persisting in the crypt is sensitive to dysregulation of adhesion, and comparison with a one-dimensional model suggests that this is caused by competition directly at the base of the crypt.\ud We also predict that increases in the extent of the spatial domain in which the mutant cells proliferate cause counter-intuitive non-linear changes to the probability of its fixation, due to effects that cannot be captured in simpler models

    Sense of Agency and Its Disruption

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    Sense of agency—the feeling of being the author of one’s actions—may be a critical component of one’s sense of self and of one’s interaction with the world. Insights from clinical and experimental neuropsychology, as well as cognitive and computational neuroscience, have provided complementary evidence that the sense of agency arises from the integration of an array of internal and external cues. These frameworks can help to explain how disruptions in one or more of these cues may result in altered experiences of agency. This chapter reviews these explanatory frameworks and shows how important and useful they have become in making sense of an array of clinical observations, from the disorders of control and agency that result from circumscribed brain damage to the widespread attenuation of agency that may characterize psychosis in which no clear brain lesion has been identified
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