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Bile duct regeneration is hypothesized to prevent biliary strictures, a leading cause of morbidity after liver transplantation. Assessing the capacity for biliary regeneration may identify grafts as suitable for transplantation that are currently declined, but this has been unfeasible until now. This study used long-term ex situ normothermic machine perfusion (LT-NMP) to assess biliary regeneration. Human livers that were declined for transplantation were perfused at 36 °C for up to 13.5 days. Bile duct biopsies, bile, and perfusate were collected throughout perfusion, which were examined for features of injury and regeneration. Biliary regeneration was defined as new Ki-67-positive biliary epithelium following severe injury. Ten livers were perfused for a median duration of 7.5 days. Severe bile duct injury occurred in all grafts, and biliary regeneration occurred in 70% of grafts. Traditional biomarkers of biliary viability such as bile glucose improved during perfusion but this was not associated with biliary regeneration (P > .05). In contrast, the maintenance of interleukin-6 and vascular endothelial growth factor-A levels in bile was associated with biliary regeneration (P = .017 for both cytokines). This is the first study to demonstrate biliary regeneration during LT-NMP and identify a cytokine signature in bile as a novel biomarker for biliary regeneration during LT-NMP.
RESUMO
Piezoelectric composite ceramics, as the key components of ultrasonic transducers, have their vibration modes, electromechanical coupling performance, and acoustic impedance closely related to the volume fraction of ceramics. This study employed a novel digital light processing 3D printing technique (DLP) to fabricate 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT)-based 1-3 piezoelectric composite ceramics with different ceramic volume fractions (15.6 %, 23.5 %, 36.2 %, 48.4 %, 59.5 %). It demonstrates the suitability of the DLP process for the fabrication of 1-3 piezoelectric composite ceramics and investigates the influence of ceramic volume fraction on the performance of these ceramics. When the piezoelectric ceramic volume fraction was 59.5 %, the piezoelectric coefficient effective d33 of the 1-3 piezoelectric composite device reached 315 pC/N, demonstrating excellent piezoelectric performance. The acoustic impedance Z was 16.3 MRayl, and the thickness electromechanical coupling coefficient kt was 0.55, indicating high energy conversion efficiency. The air-coupled ultrasonic transducer prepared from the 1-3 piezoelectric composite ceramics with a ceramic volume fraction of 59.5 % exhibited a round-trip insertion loss (IL) of -70.32 dB and a -6 dB bandwidth (BW-6dB) of 7.42 %. This work provides a more convenient and new method for the preparation of lead-free piezoelectric ceramic ultrasonic transducers.
RESUMO
ABSTRACT Introduction: In the current Chinese basketball team, many players have a high level of training. However, in official competitions, athletes tend to have heart rate problems. Therefore, it is importment to monitor and control the heart rate of basketball players to improve their performance. Objective: To explore the heart rate of basketball players in intermittent endurance training. Methods: The researchers selected 28 male basketball players from a university as the research objects. Athletes performed intermittent endurance training, and their heart rate variability, changes in frequency indicators, and changes in cardiac function were measured before and after training. Results: After training,(Total Power, TP), (High Frequency, HF), HFnorm, and (Low Frequency, LF) were significantly higher than before training. The effect sizes were medium for TP (0.7); moderate for HF (0.72); medium for HFnorm (0.59); and moderate for LFnorm (0.57). In the case of LF/HF and LF, the effect size was 0.48, close to the critical value of medium effect. Conclusions: Intermittent endurance training can improve the tension of the cardiovagal nerve of college basketball players and increase heart capacity and load, significantly improving heart function. Level of evidence II; Therapeutic studies - investigation of treatment results.
RESUMO Introdução: Muitos jogadores têm um alto nível de treinamento na atual equipe chinesa de basquetebol. Contudo, os atletas tendem a ter problemas relacionados à frequência cardíaca em competições oficiais. Portanto, é importante monitorar e controlar o batimento cardíaco visando obter a melhora de desempenho nos jogadores. Objetivo: Investigar o batimento cardíaco dos jogadores de basquetebol em treinamentos intermitentes de resistência. Métodos: Os pesquisadores selecionaram 28 jogadores de basquete em uma universidade como objeto de estudo. Esses atletas realizaram treinamento de resistência intermitente onde foram aferidas, antes e após do treino, a variabilidade de suas frequências cardíacas, as mudanças nos indicadores de frequência e as mudanças na função cardíaca. Resultados: Após o treinamento, a Potência Total (TP), a Alta Frequência (HF), a HFnorm e a Baixa Frequência (LF) foram significativamente mais altas que as aferidas previamente ao treino. O nível de alteração foi médio para TP (0,7), moderado para HF (0,72), médio para HFnorm (0,59) e moderado para LFnorm (0,57). No caso de LF/HF e LF, o tamanho da alteração foi de 0,48, próxima ao valor crítico do efeito médio. Conclusões: O treinamento de resistência intermitente pode melhorar a resistência do nervo cardiovagal nos jogadores universitários de basquete, aumentar a capacidade cardíaca e melhorar significativamente a função cardíaca. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.
RESUMEN Introducción: Muchos jugadores tienen un alto nivel de entrenamiento en el actual equipo chino de baloncesto. Sin embargo, los atletas tienden a tener problemas relacionados a la frecuencia cardiaca en competiciones oficiales. Por lo tanto, es importante monitorear y controlar la frecuencia cardíaca con el fin de obtener mejoría de desempeño en los jugadores. Objetivo: Investigar la frecuencia cardíaca en los jugadores de baloncesto en entrenamientos intermitentes de resistencia. Métodos: Los investigadores seleccionaron 28 jugadores de baloncesto en una universidad como objeto de estudio. Estos atletas realizaron entrenamiento de resistencia intermitente donde fueron medidas, antes y después del entrenamiento, la variabilidad de sus frecuencias cardíacas, los cambios en los indicadores de frecuencia y los cambios en la función cardíaca. Resultados: Después del entrenamiento, la Potencia Total (TP), la Alta Frecuencia (HF), la HFnorm y la Baja Frecuencia (LF) fueron significativamente más altas que las mediciones previas al entrenamiento. El nivel de alteración fue medio para TP (0,7), moderado para HF (0,72), medio para HFnorm (0,59) y moderado para LFnorm (0,57). En el caso de LF/HF y LF, el tamaño de la alteración fue de 0,48, cercana al valor crítico del efecto medio. Conclusiones: El entrenamiento de resistencia intermitente puede mejorar la resistencia del nervio cardiovagal en los jugadores universitarios de baloncesto, aumentar la capacidad cardíaca y mejorar significativamente la función cardíaca.. Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.