The oxyhaemoglobin dissociation curve is generally left-shifted in COVID-19 patients at admission to hospital, and this is associated with lower mortality

Lung damage caused by SARS-Cov-2 virus results in marked arterial hypoxia, accompanied in many cases by hypocapnia. The literature is inconclusive as to whether these conditions induce alteration of the affinity of haemoglobin for oxygen. We studied the oxyhaemoglobin dissociation curves (ODCs) of 517 patients hospitalized with coronavirus disease 2019 (COVID-19) for whom arterial blood gas analysis (BGA) was performed upon hospitalization (i.e., before treatment). With respect to a conventional normal p50 (pO2 at 50% saturation of haemoglobin) of 27 mmHg, 76% had a lower standardized p50 (p50s) and 85% a lower in vivo p50 (p50i). In a 33-patient subgroup with follow-up BGAs after 3, 6, 9, 12, 15 and 18 days' treatment, p50s and p50i exhibited statistically significant differences between baseline values and values recorded at all these time points. The 30-day Kaplan–Meier survival curves of COVID-19 patients stratified by p50i level show a higher probability of survival among patients who at admission had p50 values below 27 mmHg (p = 0.012). Whether the observed alteration of the affinity of haemoglobin for oxygen in COVID-19 patients is a direct or indirect effect of the virus on haemoglobin is unknownS

Postprandial glycemic response in a non-diabetic adult population: the effect of nutrients is different between men and women

Background: There is a growing interest in the pathopysiological consequences of postprandial hyperglycemia. It is well known that in diabetic patients 2 h plasma glucose is a better risk predictor for coronary heart disease than fasting plasma glucose. Data on the glycemic response in healthy people are scarce. Objective: To evaluate the effect of macronutrients (carbohydrates, fats, and proteins) and fiber on postprandial glycemic response in an observational study of a non-diabetic adult population. Design: Cross-sectional study. 150 non-diabetic adults performed continuous glucose monitoring for 6 days. During this period they recorded food and beverage intake. The participants were instructed not to make changes in their usual diet and physical exercise. Variables analyzed included clinical parameters (age, sex, body weight, height, body mass index, blood pressure, and waist measurement), meal composition (calories, carbohydrates, fats, proteins, and fiber) and glycemic postprandial responses separated by sexes. The study period was defined from the start of dinner to 6 h later. Results: A total of 148 (51% women) subjects completed all study procedures. Dinner intake was higher in males than in females (824 vs 531 kcal). Macronutrient distribution was similar in both sexes. No significant differences were found in fiber intake between men and women (5.5 g vs 4.5 g). In both sexes, the higher intake of carbohydrates corresponded to a significantly higher glycemic response (p = 0.0001 in women, p = 0.022 in men). Moreover, in women, as fat intake was higher, a flattening of the postprandial glycemic curve was observed (p = 0.003). With respect to fiber, a significantly lower glycemic response was observed in the group of women whose fiber intake at dinner was higher (p = 0.034). Conclusions: Continuous glucose monitoring provides important information about glucose levels after meals. In this study, the postprandial glycemic response in women was different from that of men, and carbohydrates were the main determinant of elevated postprandial glucose levels.This research project was supported by grants from Spain’s Carlos III Institute of Health (Instituto de Salud Carlos III/ISCIII) (PI11/02219, PI16/01395) and the European Regional Development Fund (FEDER). This work was also supported by a grant from Medtronic IbéricaS

Multi-bubble scheme and structural analysis of a hypersonic stratospheric flight vehicle

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract:] The STRATOFLY MR3 vehicle is the main objective of the STRATOFLY project, which aims to develop a hypersonic air breathing concept capable of covering antipodal routes in less than three hours. The aircraft architecture features a waverider configuration, internally supported by multi-bubble integral cryogenic tanks hosting LH2 propellant, being one of the major challenges the integration of lightweight structures with the high-speed propulsion system. The objective of this research is to completely define an efficient structural scheme of the multi-bubble structures. To do so, a multidisciplinary analysis of the full-scale aircraft model is carried out to assess the viability of the vehicle prototype. Once the flaws of the initial structural layout are identified, a set of stiffener elements were developed to generate a scheme which can withstand the loads that hypersonic flight entails. In the multi-bubble structures, a topology optimization strategy was applied to obtain a set of tension rods connecting the top and bottom parts of the bubbles to support the pressure loads. The proposed configuration was sized and analyzed for multiple points of the aircraft mission, obtaining stress levels below the failure criteria adopted for each material. In addition, the results show low displacements that guarantee an adequate aerodynamic behavior and engine performance, while mantaining global natural frequencies in the range of commercial airplanes.Ministerio de Ciencia e Innovación; PID2019-108307RB-I00Xunta de Galicia; ED431C 2017/7

An Open-Source Framework for Aircraft Damage Simulation in Engine Failure Events

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] The aerospace industry demands designs capable of withstanding the simultaneous collapse of several structural elements. Examples of this failure scenario are propeller blade or uncontained engine rotor failures, where the structural integrity of the aircraft may be compromised by flying debris. To assess aircraft survivability, reliable simulation of accidental damage scenarios using physics-based models is required. Due to the complexity of characterizing these events, practitioners and researchers have traditionally assumed conservative damage envelopes, restraining potential design improvements. This research presents an object-oriented framework to automatically generate any number of damaged aircraft meshes in a realistic manner, taking into account the randomness of the event. Due to the flexibility in the software design, both random and deterministic input parameters are allowed, such as debris origin, impact orientation, number of impacts, debris size, debris velocity, spread angles and ballistic penetration equations. The tool is applied to a commercial narrow-body aircraft in which real failure scenarios are simulated.The research leading to these results has been conducted under Grant PID2019-108307RB-I00 funded by MCIN/AEI/10.13039/501100011033 . The authors also acknowledge funding received from the Galician Government through research grant ED431C 2017/72. The first author also acknowledges the sponsorship of the Galician Government through the grant “axudas de apoio á etapa predoutoral cofinanciadas parcialmente polo programa operativo FSE Galicia 2014-2020” under identification number ED481A-2018/193. Funding for open access charge: Universidade da Coruña/CISUGXunta de Galicia; ED431C 2017/72Xunta de Galicia; ED481A-2018/19

At-admission HbA1c levels in hospitalized COVID-19 participants with and without known diabetes

Background: To examine glycaemic status, and the impact of at-admission HbA1c levels on outcome, in a large group of participants hospitalized for COVID-19. Methods: We inclued 515 participants with confirmed COVID-19 infection, with or without known diabetes, who met the following additional criteria: 1) age > 18 years, 2) HbA1c was determined at admission; 3) fasting plasma glucose was determined in the week of admission, and 4) discharge or death was reached before the end of the study. We examined attributes of participants at admission and 3–6 months post-discharge. To assess the associations of pre-admission attributes with in-hospital mortality, logistic regression analyses were performed. Results: Mean age was 70 years, 98.8% were of white race, 49% were female, 31% had known diabetes (KD), an additional 7% met the HbA1c criterion for diabetes, and 13.6% died. In participants with KD, FPG and HbA1c levels were not associated with mortality in adjusted analyses; however, in participants without KD, whereas FPG showed direct association with mortality, HbA1c showed slight inverse association. Conclusions: There was a very high prevalence of people without KD with HbA1c levels above normal at-admission. This alteration does not seem to have been related to blood glucose levelsS