Methods for Engineering Sulfate Reducing Bacteria of the Genus Desulfovibrio

Sulfate reducing bacteria are physiologically important given their nearly ubiquitous presence and have important applications in the areas of bioremediation and bioenergy. This chapter provides details on the steps used for homologous-recombination mediated chromosomal manipulation of Desulfovibrio vulgaris Hildenborough, a well-studied sulfate reducer. More specifically, we focus on the implementation of a 'parts' based approach for suicide vector assembly, important aspects of anaerobic culturing, choices for antibiotic selection, electroporation-based DNA transformation, as well as tools for screening and verifying genetically modified constructs. These methods, which in principle may be extended to other sulfate-reducing bacteria, are applicable for functional genomics investigations, as well as metabolic engineering manipulations

The twilight of the Liberal Social Contract? On the Reception of Rawlsian Political Liberalism

This chapter discusses the Rawlsian project of public reason, or public justification-based 'political' liberalism, and its reception. After a brief philosophical rather than philological reconstruction of the project, the chapter revolves around a distinction between idealist and realist responses to it. Focusing on political liberalism’s critical reception illuminates an overarching question: was Rawls’s revival of a contractualist approach to liberal legitimacy a fruitful move for liberalism and/or the social contract tradition? The last section contains a largely negative answer to that question. Nonetheless the chapter's conclusion shows that the research programme of political liberalism provided and continues to provide illuminating insights into the limitations of liberal contractualism, especially under conditions of persistent and radical diversity. The programme is, however, less receptive to challenges to do with the relative decline of the power of modern states

Constitutivism

A brief explanation and overview of constitutivism

Philosophy of action

The philosophical study of human action begins with Plato and Aristotle. Their influence in late antiquity and the Middle Ages yielded sophisticated theories of action and motivation, notably in the works of Augustine and Aquinas.1 But the ideas that were dominant in 1945 have their roots in the early modern period, when advances in physics and mathematics reshaped philosophy

A computational fluid dynamic and oxygen mass transport study of in-stent restenosis and coronary curvature

As coronary heart disease (CHD) is the greatest cause of death in developed countries (nearly 1 in 6 deaths for the U.S. in 2007), a greater need to understand its etiology has driven the work involving computer-based research. Within the realm of CHD, the greatest number of mortalities is associated with atherosclerosis, a thickening and hardening of the arterial wall, which under the most severe circumstances results in restricted blood flow to the heart and ultimately heart cell death. While systemic risk factors exist which predispose patients to atherosclerosis, such as diabetes mellitus, hyperlipidemia, and smoking, the disease has been shown to be of localized origin, mainly initiating in the inner regions of curved vessels or at bifurcations. Of these regions, coronary arteries are one of the most atheroprone due to their small caliber and large degree of curvature and tortuosity. The most popular method for treatment of occlusive arterial diseases in the 21st century is placement of a metal scaffold, known as a stent, into the stenosed region through elective percutaneous coronary intervention (PCI), thus re-establishing flow and nourishment to the heart tissue. While PCI is effective in prompt relief of ischemic symptoms, the placement of a stent still possesses several drawbacks, including a neointimal hyperplasia (NIH) in the newly stented region or stent thrombosis, leading to target-lesion revascularization for significant in-stent restenosis (ISR). Binary angiographic ISR is commonly defined as a loss greater than 50% of the initial arterial diameter gained from the stenting procedure. Numerical models are an elegant means to study the interaction of biological systems with the implanted device through evaluation of the biomechanical influences. In particular, computational fluid dynamics (CFD) provides fluid domain and mass transport solutions which may not be attainable in the clinical setting. While the introduction of hypoxia as an agent of disease initiation is not a new theory, recent indications of the correlation between ISR and hypoxia have been elucidated through in vivo, and in silico studies. In fact, the inner curvature regions of the stented model within the study by Coppola and Caro (2009) were subject to a lower oxygen flux; these regions correspond to the geometry-modified distribution of WSS. The straightened effect of the geometry due to the presence of the stent has been indicated as a means for CFD to identify the risk zones capable of forming ISR. However, there is a lack of studies which show paired histology to the computational results. The aim of this work is to utilize a methodology that combines data from in vivo experiments, 3D imaging techniques and the construction of a wall-free and fluid-wall model domain for CFD and oxygen mass transport analysis. This is carried out through exploration of the use of translational pathology (i.e. micro-Computed Tomography (micro-CT) and histology on the consecutive model) to study the influence of geometric changes, such as curvature, on hemodynamics and oxygen mass transport within the real (porcine) stented vessel and compare the results with available clinical measurements of the lesion presence versus numerically presented immediate post-implant conditions

Review of Atherosclerosis and Mathematical Transport Models

The mechanisms and definitive predictive components involved within the clinical initiation and formation of atherosclerosis remain elusive as of yet. Over the years, established fluid and mass transport theories and experimentally agreed upon vasoactive agents have contributed towards a boom of predictive mathematical models concerning atherogenesis. This paper aims to elucidate currently utilized theories available regarding initiation of atherosclerotic proliferation and provide a brief review of available mathematical transport phenomenon models which utilize these theories

Antimicrobial shape memory polymers

An embodiment includes a system comprising a thermoset polyurethane shape memory polymer (SMP) foam that includes at least one antimicrobial agent. The antimicrobial agent may include at least one phenolic acid that is a pendent group chemically bonded to a polyurethane polymer chain of the SMP foam. Other embodiments are described herein.U

Contribution of Mechanical and Fluid Stresses to the Magnitude of In-stent Restenosis at the Level of Individual Stent Struts

Structural and fluid stresses acting on the artery wall are proposed as mechanical mediators of in-stent restenosis (ISR). This study reports an investigation of the correlation between stresses obtained from computational simulations with the magnitude of ISR at the level of individual stent struts observed in an in vivo model of restenosis. Structural and fluid dynamic analyses were undertaken in a model based on volumetric micro-CT data from an in vivo stent deployment in a porcine right coronary artery. Structural and fluid mechanics were compared with histological data from the same stented vessel sample. Interpretation of the combined data at the level of individual stent struts was possible by identifying the location of each 2-D histological section within the 3-D micro-CT volume. Linear correlation between structural and fluid stimuli and neointimal thickness at the level of individual struts is less clear when individual stimuli are considered [compressive force (CF), R 2 = 0.19, wall shear stress (WSS), R 2 = 0.25, oscillatory shear index (OSI), R 2 = 0.28]. Closer correlation is observed if combined structural and fluid stimuli are assumed to stimulate ISR (CF/WSS, R 2 = 0.64). The use of micro-CT to characterise stent geometry after deployment enhances the clinical relevance of computational simulations, allowing direct comparison with histology. The results support the combined role of both structural and fluid mechanics to determine the magnitude of ISR at the level of individual struts. This finding is consistent with other studies which consider these stimuli averaged over a transverse section of the vessel

Simulation of oxygen transfer in stented arteries and correlation with in-stent restenosis

Computational models are used to study the combined effect of biomechanical and biochemical factors on coronary in-stent restenosis, which is a postoperative remodeling and regrowth pathology of the stented arteries. More precisely, we address numerical simulations, on the basis of Navier–Stokes and mass transport equations, to study the role of perturbed wall shear stresses and reduced oxygen concentration in a geometrical model reconstructed from a real porcine artery treated with a stent. Joining in vivo and in silico tools of investigation has multiple benefits in this case. On one hand, the geometry of the arterial wall and of the stent closely correspond to a real implanted configuration. On the other hand, the inspection of histological tissue samples informs us on the location and intensity of in-stent restenosis. As a result, we are able to correlate geometrical factors, such as the axial variation of the artery diameter and its curvature; the numerical quantification of biochemical stimuli, such as wall shear stresses; and the vailability of oxygen to the inner layers of the artery, with the appearance of in-stent restenosis. This study shows that the perturbation of the vessel curvature could induce hemodynamic conditions that stimulate undesired arterial remodeling