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OBJECTIVE--Type 2 diabetes is the most common form of diabetes worldwide. Some of its complications, such as retinopathy and neuropathy, are long-term and protracted, with an unclear etiology. Given this problem, genetic model systems, such as in flies where type 2 diabetes can be modeled and studied, offer distinct advantages. RESEARCH DESIGN AND METHODS--We used individual flies in experiments: control and mutant individuals with partial loss-of-function insulin pathway genes. We measured wing size and tested body weight for growth phenotypes, the latter by means of a microbalance. We studied total lipid and carbohydrate content, lipids by a reaction in single fly homogenates with vanillin-phosphoric acid, and carbohydrates with an anthronesulfuric acid reaction. Cholinesterase activity was measured using the Ellman method in head homogenates from pooled fly heads, and electroretinograms with glass capillary microelectrodes to assess performance of central brain activity and retinal function. RESULTS--Flies with partial loss-of-function of insulin pathway genes have significantly reduced body weight, higher total lipid content, and sometimes elevated carbohydrate levels. Brain function is impaired, as is retinal function, but no clear correlation can be drawn from nervous system function and metabolic state. CONCLUSIONS--These studies show that flies can be models of type 2 diabetes. They weigh less but have significant lipid gains (obese); some also have carbohydrate gains and compromised brain and retinal functions. This is significant because flies have an open circulatory system without microvascutature and can be studied without the complications of vascular defects. Diabetes 60:1632-1636, 2011, Insulin stimulates cell growth and regulates lipid and carbohydrate metabolism (1). Defects in insulin signaling lead to diabetes in humans, a chronic degenerative disease characterized by metabolic disturbances diagnosed by [...]

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In Mexico, since the early stages of the civilization, the stone masonry has assumed an important role in construction due to the wide availability of this kind of material. Masonry is a material composed by bricks, carved or even rubble stones jointed without (dry joint) or with mortar (mortar joints); which is principally formed with sand, water and cementitiuos materials. The research presented in this paper deals with the procedure of obtaining the mechanical properties of rocks placed on piers of four vehicular bridges located in the south of the state of Mexico, these mechanical properties are compressive strength, modulus of elasticity, Poisson ratio, Cohesion and Internal friction Angle of the rocks as independent units, also are reported the Density values. All of these properties are necessary to conduct further research regarding the mechanical behavior of the pier as a structure since this piece of research is part of an ongoing project concerning risk assessment of vehicular bridges developed in Mexico. The identified rocks in masonry were volcanic igneous materials such as dacites, basalts, rhyolites, andesites and rusted andesites. The materials with the highest and the lowest mechanical properties are the basalt and the dacite respectively. It is recommended to use the dacite’s properties in order to perform a conservative analysis of the mechanical behavior of any masonry structure, located near the selected sample studied herein.

One of the responsibilities of a Civil Engineer is to make decisions regarding preservation of infrastructure; therefore, there have been established concepts such as risk and risk analysis. Risk analysis, is a methodology applied to determine and evaluate the risk magnitude. From the structural engineering point of view, it is required that any structure become secure, this means that the capacity to withstand external actions (strength) will be higher than these actions (loads). In order to determine the structural safety, it is required to define the failure of the structure that it is not strongly related with the collapse of the structure; the failure criteria needs to be fixed depending on the use of the building and the consequences associated with the interruption of services provided by the facility. The failure then, is calculated by means of a limit state function in where it is established the failure criteria; failure is reached when a specific condition (strength) is surpassed by the actions over the structure. The present work aims to propose a preliminary Finite Element Model (FEM) that represents a pier used as support for vehicular bridges. This FEM is required for the assessment of mechanical behavior of the structure that will be used for the determination of the limit state function needed for risk assessment. Most of the simulations with FEM presented in literature are very used for modeling of masonry walls, but it is not usual to model structures such as bridge piers.

Letters to the editor are presented concerning the articles "Take That Texas" and "What the Backer Sees" from the December 1, 2008 issue and the story "A More Dangerous Game" by Matthew Teague from the November 24, 2008 issue.