Structures of (5′S)-8,5′-Cyclo-2′-deoxyguanosine Mismatched with dA or dT

pubs.acs.org/cr

Why Can't Rodents Vomit? A Comparative Behavioral, Anatomical, and Physiological Study

The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats and mice appear to lack this response. It is unclear whether these rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or lack of key neural circuits. Moreover, it is unknown whether laboratory rodents are representative of Rodentia with regards to this reflex. Here we conducted behavioral testing of members of all three major groups of Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), and squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine (sc), and copper sulfate (ig), failed to produce either retching or vomiting in these species (although other behavioral effects, e.g., locomotion, were noted). These rodents also had anatomical constraints, which could limit the efficiency of vomiting should it be attempted, including reduced muscularity of the diaphragm and stomach geometry that is not well structured for moving contents towards the esophagus compared to species that can vomit (cat, ferret, and musk shrew). Lastly, an in situ brainstem preparation was used to make sensitive measures of mouth, esophagus, and shoulder muscular movements, and phrenic nerve activity-key features of emetic episodes. Laboratory mice and rats failed to display any of the common coordinated actions of these indices after typical emetic stimulation (resiniferatoxin and vagal afferent stimulation) compared to musk shrews. Overall the results suggest that the inability to vomit is a general property of Rodentia and that an absent brainstem neurological component is the most likely cause. The implications of these findings for the utility of rodents as models in the area of emesis research are discussed. © 2013 Horn et al

New technologies as opportunities for flow experience: A framework for the analysis

New technologies present remarkable opportunities for flow experience. We provide an integrated theoretical framework for the study of flow in Human- Technologies Interaction referring to two specific cognitive processes - presence and social presence - whose goals are the control of the activity of the Self (presence) and the understanding of the activity of the Other (social presence). On the individual level, the chance for a technology user to enter a state of flow depends on how much the technology addresses the user\u2019s hierarchy of intentions (presence): I am present in a real or virtual space if I manage to put my intentions into action (enacting them). On this basis, we elaborate on a new model aimed to describe how a "Perfect Interaction" (P.I.M.) takes place. On the collective level, research shows that a peculiar type of flow state could be reached by creative groups. Central to the presented model is the definition of a shared intersubjective space, which we identify with (highest level of) social presence. When this is achieved, participants can experience networked flow, an optimal state that maximizes the creative potential of the group