A finite-strain solid–shell using local Löwdin frames and least-squares strains

A finite-strain solid–shell element is proposed. It is based on least-squares in-plane assumed strains, assumed natural transverse shear and normal strains. The singular value decomposition (SVD) is used to define local (integration-point) orthogonal frames-of-reference solely from the Jacobian matrix. The complete finite-strain formulation is derived and tested. Assumed strains obtained from least-squares fitting are an alternative to the enhanced-assumed-strain (EAS) formulations and, in contrast with these, the result is an element satisfying the Patch test. There are no additional degrees-of-freedom, as it is the case with the enhanced-assumed-strain case, even by means of static condensation. Least-squares fitting produces invariant finite strain elements which are shear-locking free and amenable to be incorporated in large-scale codes. With that goal, we use automatically generated code produced by AceGen and Mathematica. All benchmarks show excellent results, similar to the best available shell and hybrid solid elements with significantly lower computational cost

Perinatal profile of ventricular overload markers in congenital diaphragmatic hernia

Background: In congenital diaphragmatic hernia (CDH), pulmonary hypertension increases right ventricle (RV) afterload, which could impair heart function and contribute to poor outcome for most affected infants. Nevertheless, the real significance of vascular pulmonary alterations in perinatal hemodynamics is largely unknown. It is defined that ventricular pressure overload induces increased myocardium gene expression of B-type natriuretic peptide (BNP) and components of the reninangiotensinogen and endothelin (ET)–1 systems. Our aim was to evaluate perinatal myocardium expression of these genes associated with ventricular pressure overload in a nitrofen-induced CDH rat model. Methods: In the nitrofen-induced CDH rat model, fetuses from dated pregnant Sprague-Dawley rats at 15.5, 17.5, 19.5 and 21.5 days postcoitum as well as newborn pups were assigned to 3 experimental groups: control, nitrofen (exposed to nitrofen, without CDH), and CDH (exposed to nitrofen, with CDH). Myocardial samples collected from the RV and left ventricle (LV) were processed for quantification of messenger RNA (mRNA) of BNP, angiotensinogen, and ET-1. Results: The perinatal expression of BNP, angiotensinogen, and ET-1 mRNA in the RV and LV of the control group revealed daily changes. During gestation, the expression of BNP and angiotensinogen mRNA underwent significant oscillation compared with control in both nitrofen-exposed fetuses, although we cannot identify significant differences between the nitrofen and CDH groups. After birth, we found a significant increasing expression of all studied genes only in the RV of CDH pups. Conclusions: Perinatal myocardial quantification of BNP, angiotensinogen, and ET-1 mRNA levels suggests that both nitrofen-exposed and control pups revealed prenatal variations of expression of the studied genes. Moreover, CDH is associated with significant molecular alterations only in the RV after birth

Cardiovascular rhythmicity in overweight and obese children

Abstract Introduction: Obesity is thought to play a role in the disruption of cardiac rhythmicity in obese children, but this is mostly an unexplored field of investigation. We aimed to evaluate the impact of overweight and obesity on circadian and ultradian cardiovascular rhythmicity of prepubertal children, in comparison with normal weight counterparts. Methods: We performed a cross sectional study of 316 children, followed in the birth cohort Generation XXI (Portugal). Anthropometrics and 24-hour ambulatory blood pressure were measured and profiles were examined with Fourier analysis for circadian and ultradian blood pressure (BP) and heart rate (HR) rhythms. Results: Overweight/obese children presented more frequently a non-dipping BP pattern than normal weight counterparts (31.5% vs. 21.6%, p = 0.047). The prevalence of 24-hour mean arterial pressure (MAP) and 8-hour HR rhythmicity was significantly lower in obese children (79.3% vs. 88.0%, p = 0.038 and 33.3% vs. 45.2%, p = 0.031, respectively). The prevalence of the remaining MAP and HR rhythmicity was similar in both groups. No differences were found in the median values of amplitudes and acrophases of MAP and HR rhythms. Discussion: The alterations found in rhythmicity suggest that circadian and ultradian rhythmicity analysis might be sensitive in detecting early cardiovascular dysregulations, but future studies are needed to reinforce our findings and to better understand their long-term implications

Reshaping digital methodologies to the analog world

Analog and digital design are subjects in the Electronic Engineering curricula. Being apparently similar subjects they are quite contradictory in design flow level as a result of each technological area maturation state. As so, teaching methodologies are also very different, being challenging for both teachers and students. In fact, electronic design in the digital field is centered in the use of microprocessor and FPGA based circuits taking advantage from the relatively high level programing/configuring languages such as C or VHDL. Later on, at the debug stage, all changes will take place at software level only, being relatively easy to implement them. In a very different way, the analog design is traditionally based on the use of elementary components associated with macroblocks in order to built-up the wanted mission circuit. At the debug stage any circuit modification embraces necessarily some degree of hardware changing, with the all associated difficulties. As result, a massive share of electronic engineering students prefers to develop electronic work only at digital arena, generating um undesirable and unbalanced situation. This work relates the analog and digital design flow and proposes the use of analog programmable/configurable (e.g. FPAA, PSoC) circuits as a way to get the analog arena more attractive for electronic student and therefore balance analog and digital arenas at number of students level. This strategy, however, bring some drawbacks once it evolves the use of concepts not often taught in the traditional analog design classes. To surpass then is proposed the development of dedicated pedagogical materials making use of the ICT and including dedicated remote labs.info:eu-repo/semantics/publishedVersio