Analyzing the determinants of carbon emissions from transportation in European countries: the role of renewable energy and urbanization

Clean Technologies and Environmental Policy - The continuous growth of transport sector and the increase in carbon emissions from transportation attract the attention of policy makers in...     

Mechanisms of Colorectal Cancer Prevention by Aspirin—A Literature Review and Perspective on the Role of COX-Dependent and -Independent Pathways

Aspirin, synthesized and marketed in 1897 by Bayer, is one of the most widely used drugs in the world. It has a well-recognized role in decreasing inflammation, pain and fever, and in the prevention of thrombotic cardiovascular diseases. Its anti-inflammatory and cardio-protective actions have been well studied and occur through inhibition of cyclooxygenases (COX). Interestingly, a vast amount of epidemiological, preclinical and clinical studies have revealed aspirin as a promising chemopreventive agent, particularly against colorectal cancers (CRC); however, the primary mechanism by which it decreases the occurrences of CRC has still not been established. Numerous mechanisms have been proposed for aspirin’s chemopreventive properties among which the inhibition of COX enzymes has been widely discussed. Despite the wide attention COX-inhibition has received as the most probable mechanism of cancer prevention by aspirin, it is clear that aspirin targets many other proteins and pathways, suggesting that these extra-COX targets may also be equally important in preventing CRC. In this review, we discuss the COX-dependent and -independent pathways described in literature for aspirin’s anti-cancer effects and highlight the strengths and limitations of the proposed mechanisms. Additionally, we emphasize the potential role of the metabolites of aspirin and salicylic acid (generated in the gut through microbial biotransformation) in contributing to aspirin’s chemopreventive actions. We suggest that the preferential chemopreventive effect of aspirin against CRC may be related to direct exposure of aspirin/salicylic acid or its metabolites to the colorectal tissues. Future investigations should shed light on the role of aspirin, its metabolites and the role of the gut microbiota in cancer prevention against CRC.     

Particle Swarm Optimization with Parameter Dependency Walls and its sample application to the microstrip-like interconnect line design

In this paper, we first propose and formulate a novel approach in Particle Swarm Optimization (which we call “Particle Swarm Optimization with Parameter Dependency Walls”) for handling the dependencies between the design parameters. After revisiting the definition of Particle Swarm Optimization; we try to visualize the physical meaning of the concepts lying beneath our approach, and demonstrate the existence of analytical solution needed throughout the implementation. In order to illustrate a practical application of our approach, we first revisit the empirical closed-form characteristic impedance expression for the microstrip-like interconnect line with a ground plane aperture. Then, we apply our approach in order to calculate the optimized parameters of microstrip-like interconnect lines in the synthesis problem. The proposed procedure can be useful for the rapid solution of the optimization problems in which there exist dependencies between/among the input variables.