Elastic properties of TeO2-B2O3-Ag2O glasses.

A series of glasses [(TeO2) x (B2O3)1−x ]1−y [Ag2O] y with x = 70 and y = 10, 15, 20, 25 and 30 mol% were synthesised by rapid quenching. Longitudinal and shear ultrasonic velocity were measured at room temperature and at 5 MHz frequency. Elastic properties, Poisson's ratio, microhardness, softening temperature and Debye temperature have been calculated from the measured density and ultrasonic velocity at room temperature. The experimental results indicate that the elastic constants depend upon the composition of the glasses and the role of the Ag2O inside the glass network is discussed. Estimated parameters based on Makishima–Mackenzie theory and bond compression model were calculated in order to analyse the experimental elastic moduli. Comparison between the experimental elastic moduli data obtained in the study and the calculated theoretically by the mentioned above models has been discussed

The Semiosis of “Side Effects” in Genetic Interventions

Genetic interventions, which include transgenic engineering, gene editing, and other forms of genome modification aimed at altering the information “in” the genetic code, are rapidly increasing in power and scale. Biosemiotics offers unique tools for understanding the nature, risks, scope, and prospects of such technologies, though few in the community have turned their attention specifically in this direction. Bruni (2003, 2008) is an important exception. In this paper, I examine how we frame the concept of “side effects” that result from genetic interventions and how the concept stands up to current perspectives of the role of organism activity in development. I propose that once the role of living systems in constructing and modifying the informational value of their various developmental resources is taken into account, the concept of a “side effect” will need to be significantly revised. Far from merely a disturbance brought about in a senseless albeit complex system, a biosemiotic view would take “side effects” as at least sometimes the organism’s active re-organization in order to accommodate or make use of novelty. This insight is nascent in the work of developmental plasticity and niche construction theory (West-Eberhard 2003; Odling-Smee et al. 2003), but it is brought into sharper focus by the explicitly interpretive perspective offered by biosemiotics. Understanding the “side effects” of genetic interventions depends in part on being able to articulate when and where unexpected consequences are a result of semiotic activity at various levels within the system. While a semiotic interpretation of “side effects” puts into question the naive attitude that would see all unintended side effects as indications of disturbance in system functionality, it certainly does not imply that such side effects are of no concern for the viability of the organisms in the system. As we shall see, the fact that such interventions do not respect the translation of information that occurs in multi-level biological systems ensures that disruption is still likely. But it does unprivilege the human agent as the sole generator of meaning and information in the products of biotechnology, with important consequences on how we understand our relationship with other species