The outcome of mediastinal reconstruction during the past 10 years at the "Instituto Nacional de Cardiología Ignacio Chávez" (INCIC), Mexico City was compared. A total of 7136 patients were submitted to open heart surgery. Eighty-two patients (1.15 percent) developed mediastinitis, and 33 patients (0.46 percent) developed sternal osteomyelitis. Only patients who developed mediastinitis with sternal osteomyelitis were included in the study. Reconstruction was performed either with a major omentum flap (12 patients) or a pectoralis major flap (21 patients). The sepsis-related mortality rate was higher in the pectoralis group (28.6 percent) than in the omentum group (0 percent) (p < 0.05). All of the postoperative deaths of the pectoralis group were caused by septic shock; in the omentum group, there were no such deaths. It is concluded that mediastinal reconstruction using the omentum flap in patients with mediastinitis secondary to open heart surgery is associated with fewer septic complications than using the pectoralis major flap.

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Bicuspid aortic valve (BAV) is the most common human congenital cardiac malformation. Although the etiology is unknown for most patients, formation of the 2 main BAV anatomic types (A and B) has been shown to rely on distinct morphogenetic mechanisms. Animal models of BAV include 2 spontaneous hamster strains and 27 genetically modified mouse strains. To assess the value of these models for extrapolation to humans, we examined the aortic valve anatomy of 4340 hamsters and 1823 mice from 8 and 7 unmodified strains, respectively. In addition, we reviewed the literature describing BAV in nonhuman mammals. The incidences of BAV types A and B were 2.3% and 0.03% in control hamsters and 0% and 0.3% in control mice, respectively. Hamsters from the spontaneous model had BAV type A only, whereas mice from 2 of 27 genetically modified strains had BAV type A, 23 of 27 had BAV type B, and 2 of 27 had both BAV types. In both species, BAV incidence was dependent on genetic background. Unlike mice, hamsters had a wide spectrum of aortic valve morphologies. We showed interspecific differences in the occurrence of BAV between humans, hamsters, and mice that should be considered when studying aortic valve disease using animal models. Our results suggest that genetic modifiers play a significant role in both the morphology and incidence of BAV. We propose that mutations causing anomalies in specific cardiac morphogenetic processes or cell lineages may lead to BAV types A, B, or both, depending on additional genetic, environmental, and epigenetic factors.

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Augmented reality (AR) has evolved hand in hand with advances in technology, and today is considered as an emerging technique in its own right. The aim of our study was to analyze students' perceptions of how useful AR is in the school environment. A non-experimental quantitative design was used in the form of a questionnaire in which 106 primary sixth-grade students from six schools in the Region of Murcia (Spain) participated. During the study, a teaching proposal using AR related to the content of some curricular areas was put forward in the framework of the 3P learning model. The participants' perceptions of this technique were analyzed according to each variable, both overall and by gender, via a questionnaire of our own making, which had previously been validated by AR experts, analyzing its psychometric qualities. The initial results indicate that this technique is, according to the students, useful for teaching the curriculum. The conclusion is that AR can increase students' motivation and enthusiasm while enhancing teaching and learning at the same time.Appl. Sci. 2019, 9, 5426 2 of 16 of AR and boost its development, showing how satisfaction, motivation and other positive variables are manifested in the participants in a noticeable way after its implementation. Conceptualization and TerminologyCaudell and Mizell [4], who coined the concept, define AR as a technology that enhances the user's field of vision with the information necessary to perform a task, thanks to computational processes that can transform and chart simple graphics in real time. Milgram and Kishino [5] add to this definition when they describe AR as any case in which a real environment is enhanced with virtual objects (computer graphics). Likewise, they present the term within a taxonomy (a virtuality continuum), in which all the possible types of viewing appear. Within this continuum, the real and virtual elements coexist in a single mixed reality space where AR is closer to the entirely real environment than to the entirely virtual environment. Another pioneer, Azuma [6], sees AR as a variation of virtual environments which enables the user to see reality through superimposed objects.It is noteworthy that some authors [7,8] have contradicted the idea of presenting AR conceptually as a technology in the strict sense, since it can be based on technology or understood as a resource that can accompany technology or draw from it, which means that it is necessary to interpret it beyond this exclusively classificatory treatment. Hence, one approach to this issue could be that AR is an emerging technique which is mediated by technology and which enables the superimposition of virtual information on a real environment, thus facilitating access to the borders of mixed reality, which can be two-or three-dimensional.