Effectiveness of Helmet-CPAP in mild to moderate coronavirus type 2 hypoxemia: An observational study.

OBJECTIVE: To determine the relative effectiveness of Helmet-CPAP (H_CPAP) with respect to high-flow nasal cannula oxygen therapy (HFNO) in avoiding greater need for intubation or mortality in a medium complexity hospital in Chile during the year 2021. DESIGN: Cohort analytical study, single center. SETTING: Units other than intensive care units. PATIENTS: Records of adults with mild to moderate hypoxemia due to coronavirus type 2. INTERVENTIONS: None. MAIN VARIABLES OF INTEREST: Need for intubation or mortality. RESULTS: 159 patients were included in the study, with a ratio by support of 2:10 (H_CPAP:HFNO). The 46.5% were women, with no significant differences by sex according to support (p = 0.99, Fisher test). The APACHE II score, for HFNO, had a median of 10.5, 3.5 units higher than H_CPAP (p < 0.01, Wilcoxon rank sum). The risk of intubation in HFNO was 42.1% and in H_CPAP 3.8%, with a significant risk reduction of 91% (95% CI: 36.9%-98.7%; p < 0.01). APACHE II does not modify or confound the support and intubation relationship (p > 0.2, binomial regression); however, it does confound the support and mortality relationship (p = 0.82, RR homogeneity test). Despite a 79.1% reduction in mortality risk with H_CPAP, this reduction was not statistically significant (p = 0.11, binomial regression). CONCLUSIONS: The use of Helmet CPAP, when compared to HFNO, was an effective therapeutic ventilatory support strategy to reduce the risk of intubation in patients with mild to moderate hypoxemia caused by coronavirus type 2 in inpatient units other than intensive care. The limitations associated with the difference in size, age and severity between the arms could generate bias.

In Situ, Real-Time Temperature Mapping and Thermal FE Simulations of Large-Format 3D Printed PETG/CF Vertical Wall.

This work focuses on simulating the thermal history of a vertical wall consisting of a thermoplastic composite material, poly(ethylene terephthalate) glycol (PETG) with short carbon fiber reinforcement, manufactured using a Big Area Additive Manufacturing (BAAM) system. The incremental deposition process used in additive manufacturing, which corresponds to the repeated deposition of hot material onto cooler material, contributes to the presence of residual stresses and part warping. The prediction of these mechanisms is dependent on thermal history of the part, and the major motivation of this work was to improve the accuracy of finite element (FE) models used to quantify the thermal history of large-format additively manufactured parts. Thermocouples were placed throughout the part at varying heights to measure temperature as a function of time. The FE model developed found a thermal contact conductance between the printed part and the bed of 10 W/m2K and convection coefficient values that linearly varied from 3 to 15 W/m2K through the wall height when making a temperature comparison with the output from the thermocouples. It is also demonstrated that the FE model with a constant convection coefficient under-predicts model temperature at the beginning of the manufacturing process when compared against the model with a variable convection coefficient. The impact of this difference was seen in the stress values, which were larger for the model with a constant convection coefficient. Finally, a correlation equation was derived which allows the findings to be generalized to other vertical structures manufactured on the BAAM. In summary, this work offers valuable insights on material characterization, real-time thermocouple placement, and FE modeling of large-format additively manufactured parts.

Asociación entre velocidad de marcha y deterioro cognitivo en personas mayores: resultados de la Encuesta Nacional de Salud 2016-2017

Antecedentes: La velocidad de la marcha podría considerarse un marcador temprano de riesgo de deterioro cognitivo en personas mayores. Objetivo: Determinar la asociación entre velocidad de la marcha y sospecha de deterioro cognitivo en población mayor chilena. Métodos: Se incluyeron 1788 personas mayores de la Encuesta Nacional de Salud (ENS) 2016-2017 que tenían información sobre velocidad de marcha y sospecha de deterioro cognitivo. La velocidad de la marcha fue autorreportada y categorizada como marca lenta, normal y rápida. Sospecha de deterioro cognitivo fue evaluado a través del cuestionario Mini Mental abreviado. La asociación entre marcha y deterioro cognitivo fue investigada mediante análisis de regresión logística. Resultados: En comparación a las personas mayores que reportaron una velocidad de marcha rápida, aquellas que reportaron una marcha lenta presentaron 2,67 veces mayor probabilidad de tener deterioro cognitivo (OR: 2,67 [95% IC:1,62; 4,42], p<0,001). Al ajustar los modelos por variables de confusión sociodemográficas, estilos de vida y salud, la asociación disminuyó, pero, permaneció significativa (OR: 1,78 [95% IC:1,15; 3,17], p=0,047). Mientras que las personas mayores que reportaron tener una velocidad de marcha normal no presentaron asociación con deterioro cognitivo. Conclusión: Personas mayores que reportan una velocidad de marcha lenta presentaron una mayor probabilidad de sospecha de deterioro cognitivo. Considerando que el deterioro cognitivo es un síndrome geriátrico con alta prevalencia en población mayor, existe la necesidad de enfatizar en estrategias para un diagnóstico temprano, por lo cual la velocidad de marcha podría ser un instrumento útil.

Background: Walking pace could be considered an early risk marker of cognitive impairment in older people. Objective: To determine the association between walking pace and cognitive impairment in older Chilean adults. Methods: 1,788 adults older than 60 years from the 2016-2017 Chilean National Health Survey with data available in the exposure and outcome were included in this cross-sectional study. Walking pace was self-reported and categorised as slow, average and brisk. Cognitive impairment was assessed using the Abbreviated Mini-Mental questionnaire. Logistic regression analyses were performed to investigate the association between walking pace and cognitive impairment, logistic regression analyses - adjusted for sociodemographic, lifestyle and health-related covariates. Results: In the minimally adjusted model and compared to older adults who self-reported a brisk walking pace, those in the slow walking pace category were 2.67 times more likely to have cognitive impairment (OR: 2.67 [95% CI: 1.62, 4.42]). When the analyses were adjusted, the association was attenuated but remained significant (OR: 1.78 [95% CI: 1.15 3.17]). No associations were found between average pace walkers and cognitive impairment. Conclusion: Older adults who self-reported a slow walking pace having a higher likelihood of cognitive impairment than their counterparts who had a brisk walking pace. Considering that cognitive impairment is a geriatric syndrome with a high prevalence in the elderly, there is a need to emphasise strategies for an early diagnosis. Therefore, walking pace may be a useful marker to identify individuals at high risk of cognitive impairment.

Anelasticity in thin-shell nanolattices.

In this work, we investigate the anelastic deformation behavior of periodic three-dimensional (3D) nanolattices with extremely thin shell thicknesses using nanoindentation. The results show that the nanolattice continues to deform with time under a constant load. In the case of 30-nm-thick aluminum oxide nanolattices, the anelastic deformation accounts for up to 18.1% of the elastic deformation for a constant load of 500 µN. The nanolattices also exhibit up to 15.7% recovery after unloading. Finite element analysis (FEA) coupled with diffusion of point defects is conducted, which is in qualitative agreement with the experimental results. The anelastic behavior can be attributed to the diffusion of point defects in the presence of a stress gradient and is reversible when the deformation is removed. The FEA model quantifies the evolution of the stress gradient and defect concentration and demonstrates the important role of a wavy tube profile in the diffusion of point defects. The reported anelastic deformation behavior can shed light on time-dependent response of nanolattice materials with implication for energy dissipation applications.

Multifunctional Electronic Textiles Using Silver Nanowire Composites.

Textiles represent an appealing platform for continuous wearable applications due to the exceptional combination of compliance, water vapor permeability, and comfortableness for long-term wear. We present mechanically and electrically robust integration of nanocomposites with textiles by laser scribing and heat press lamination. The simple and scalable integration technique enables multifunctional E-textiles without compromising the stretchability, wearability, and washability of textiles. The textile-integrated patterns exhibit small line width (135 µm), low sheet resistance (0.2 Ω/sq), low Young's modulus, good washability, and good electromechanical performance up to 50% strain, which is desirable for wearable and user-friendly electronic textiles. To demonstrate the potential utility, we developed an integrated textile patch comprising four dry electrophysiological electrodes, a capacitive strain sensor, and a wireless heater for electrophysiological monitoring, motion tracking, and thermotherapy, respectively. Beyond the applications demonstrated in this paper, the materials and methods presented here pave the way for various other wearable applications in health care, activity tracking, rehabilitation, sports medicine, and human-machine interactions.

Tailoring the Temperature Coefficient of Resistance of Silver Nanowire Nanocomposites and their Application as Stretchable Temperature Sensors.

Body temperature is an important indicator of the health condition. It is of critical importance to develop a smart temperature sensor for wearable applications. Silver nanowire (AgNW) is a promising conductive material for developing flexible and stretchable electrodes. Here, a stretchable and breathable thermoresistive temperature sensor based on AgNW composites is developed, where a AgNW percolation network is encased in a thin polyimide film. The temperature coefficient of resistance of the AgNW network is tailored by modifying nanowire density and thermal annealing temperature. The temperature sensor is patterned with a Kirigami structure, which enables constant resistance under a large tensile strain (up to 100%). Demonstrated applications in monitoring the temperatures at biceps and knees using the stretchable temperature sensor illustrate the promising potential for wearable applications.

Large-Area Nanolattice Film with Enhanced Modulus, Hardness, and Energy Dissipation.

We present an engineered nanolattice material with enhanced mechanical properties that can be broadly applied as a thin film over large areas. The nanolattice films consist of ordered, three-dimensional architecture with thin-shell tubular elements, resulting in favorable modulus-density scaling (n ~ 1.1), enhanced energy dissipation, and extremely large material recoverability for strains up to 20% under normal compressive loading. At 95.6% porosity, the nanolattice film has demonstrated modulus of 1.19 GPa and specific energy dissipation of 325.5 kJ/kg, surpassing previously reported values at similar densities. The largest length scale in the reported nanolattice is the 500 nm unit-cell lattice constant, allowing the film to behave more like a continuum material and be visually unobservable. Fabricated using three-dimensional colloidal nanolithography and atomic layer deposition, the process can be scaled for large-area patterning. The proposed nanolattice film can find applications as a robust multifunctional insulating film that can be applied in integrated photonic elements, optoelectronic devices, and microcircuit chips.

Análise por meio do método dos elementos finitos de um protetor bucal para atividades esportivas / Finite elements analisis in mouthguard for sports ativities

O uso de protetores bucais na prática de esportes tem ampliado espaço no contexto da prevenção de traumas bucais, bem como apresentado melhoria no desempenho ao longo de sua história. O objetivo deste trabalho foi avaliar o comportamento do complexo bucodentoalveolar por meio do método dos elementos finitos. O estudo partiu de um modelo em formato esterolitográfico oriundo de uma tomografia computadorizada, o qual foi convertido para um modelo 3D pelo programa Rhinoceros® versão 4.0, sem protetor bucal (controle) e com protetor bucal de 4,0 mm de espessura em EVA (copolímero de etileno e acetato de vinila), os quais receberam duas cargas diferentes (500, 1000 N) no programa ANSYS® v.12 em regime quase estático e de caráter elástico linear. Pudemos observar que houve um padrão de comportamento das estruturas envolvidas quanto à dissipação das tensões geradas e ao se comparar o modelo controle com o modelo provido de protetor bucal houve uma absorção das tensões geradas em até 50%, permitindo confirmar a ação do protetor bucal em literatura e tornando o seu uso imperativo durante a prática de esportes, em especial as modalidades de maior contato.

The use of mouthguards in the practice of sports has expanded space in the prevention of oral trauma, and has presented performance improvement over its history. The aim of this study was to evaluate the behavior of complex dento alveolar buccal through the finite element method. The study was based on a template stereolitographic format come from a CT scan, which was converted to a 3D model by the program Rhinoceros® version 4.0, without a mouthguard (control) and mouthguard 4.0 mm thick copolymer of ethylene and vinyl acetate (EVA), which received two different loads (500, 1000 N) in ANSYS® v.12 under quasi-static linear and elastic character. We noticed that there was a pattern of behavior of the structures involved about the dissipation of tensions generated, and when the model was compared with the control model fitted with a mouthguard there was an absortion of the stresses generated in up to 50%, allowing to confirm the action of the mouthguard in literature and making its use mandatory for the practice of sports, especially the arrangements for closer contact.

Análise por meio do método dos elementos finitos de um protetor bucal para atividades esportivas / Analysis through the finite element method of a mouthguard for sports activities

O uso de protetores bucais na prática de esportes tem ampliado espaço no contexto da prevenção de traumas bucais, bem como apresentado melhoria no desempenho ao longo de sua história. O objetivo deste trabalho foi avaliar o comportamento do complexo buco dento alveolar (lábio, dentes, osso alveolar e ligamento periodontal) por meio do método dos elementos finitos. A metodologia utilizada foi a partir de um modelo em formato esterolitográfico oriundo de uma tomografia computadorizada, o qual foi convertido para um modelo 3D pelo programa Rhinoceros® versão 4.0 sem protetor bucal (controle) e com protetor bucal de 4.0mm de espessura em EVA (copolímero de etileno e acetato de vinila), os quais receberam três cargas diferentes (500, 1000 e 1500N) no programa ANSYS® v12 em regime quaseestático, de caráter elástico linear. Pudemos observar que houve um padrão de comportamento das estruturas envolvidas quanto à dissipação das tensões geradas e ao se comparar o modelo controle com o modelo provido de protetor bucal houve uma absorção das tensões geradas em até 50%, permitindo confirmar a ação do protetor bucal em literatura e tornando o seu uso imperativo durante a prática de esportes, em especial as modalidades de maior contato.

The use of mouthguards in the practice of sports has expanded space in the prevention of oral trauma, and presented performance improvement over its history. The aim of this study was to evaluate the behavior of complex buco dental alveolar (lip, teeth, periodontal ligament and alveolar bone) through the finite element method. The methodology used was based on a sterelithographic model come from a CT scan, which was converted to a 3D model by the program Rhinoceros® version 4.0 without a mouthguard (control) and mouthguard 4.0mm-thick EVA (copolymerof ethylene and vinyl acetate), which received three different loads (500, 1000 and 1500N) in ANSYS® v12 under quasi-static, linear elastic character. We noticed that there was a pattern of behavior of the structures involved and the dissipation of the tensions generated and compare the model with the control model was fitted with a mouthguard absorbs stresses generated by 50%, allowing to confirm the action of the mouthguard in literature and making its use mandatory for participation in sports, in particular the modalities for greater contact.