Bioinspired PLCL/Elastin Nanofibrous Vascular Tissue Engineering Scaffold Enhances Endothelial Cells and Inhibits Smooth Muscle Cells.

In vascular tissue engineering, a scaffold that can enhance the proliferation of endothelial cells (ECs) while inhibiting the synthetic differentiation of smooth muscle cells (SMCs) is crucial to prevent thrombus and restenosis after graft implantation. However, it is always challenging to incorporate both properties simultaneously in a vascular tissue engineering scaffold. In this study, a novel composite material was developed by combining a synthetic biopolymer of poly(l-lactide-co-caprolactone) (PLCL) and a natural biopolymer of elastin through electrospinning. Cross-linking of the PLCL/elastin composite fibers using EDC/NHS was performed to stabilize the elastin component. The incorporation of elastin into PLCL was found to enhance the hydrophilicity and biocompatibility of the resulting PLCL/elastin composite fibers, as well as the mechanical properties. Additionally, as a natural component of the extracellular matrix, elastin displayed antithrombotic properties reducing platelet adhesion and improving blood compatibility. Results of cell culture experiments with human umbilical vein ECs (HUVECs) and human umbilical artery SMCs (HUASMCs) showed that the composite fiber membrane had high cell viability, promoting the proliferation and adhesion of HUVECs and inducing a contractile phenotype in HUASMCs. These results indicate that the PLCL/elastin composite material has great potential for use in vascular graft applications due to its favorable properties and rapid endothelialization and contractile phenotypes of cells.

Conceptualizing maternal and paternal autonomy support and control among adolescents in Hong Kong.

This study examined how parental autonomy support and control are conceptualized by adolescents in Hong Kong (Grades 7-11) using the Perceived Parental Autonomy Support Scale. Competitive models were evaluated using confirmatory factor analyses. Although the 6-factor model demonstrated the best fit, further analyses indicated that a second-order structure was more appropriate. Provision of choice, acknowledgment of child's feelings, rationale for rules, and demands subsumed under autonomy support. Guilt-inducing criticisms and the use of threats subsumed under control. Performance pressure emerged as a first-order construct on its own. Measurement invariance was evident across adolescent gender and age. All subscales had adequate to strong reliability. Discriminate validity was evident. Findings offer insights into the conceptualization of autonomy support and control in Hong Kong.

Microinjection Molded Biopolymeric Airway Stent with Antibacterial and Anti-Hyperplastic Properties.

Central airway stenosis is a condition that the diameter of the trachea or main bronchus shrinkage is caused by external compression or internal tissue hyperplasia, which can cause difficulty breathing, asphyxia, and even death. Airway stenting is an easy way to restore the patency of the central airway, but airway stents commonly used in clinical practice can lead to complications such as mucus plugging, bacterial infection, and granulation tissue hyperplasia. Moreover, the non-degradable characteristic makes it requires a second operation to remove, which has the potential to cause tissue damage. In this study, a biodegradable airway stent is fabricated by microinjection molding using the bioelastomer of poly (L-lactide-co-ε-caprolactone) as the matrix material. The airway stent has excellent mechanical properties and an appropriate degradation rate. The hydrophilic surface of the airway stent can inhibit mucus plugging. The loading of silver nanoparticles and cisplatin endows the stent with antibacterial and anti-hyperplastic functions. In vitro and in vivo experiments demonstrate that this study provides an antibacterial and anti-hyperplastic biodegradable airway stent with elastic properties to avoid secondary removal operation and reduce complications associated with mucus plugging, bacterial infection, and granulation tissue hyperplasia.

A battery-powered over-voltage triggering method for two-electrode spark gaps in Marx generator.

Triggered gas switches with trigger electrodes, such as three-electrode spark switches and trigatron type spark switches, have been widely used in repetitive operating Marx generators due to their large current flowing capability. However, the ablation of trigger electrodes during repetitive operation is inevitable, which reduces the working life of triggered gas switches. In this paper, we introduced an over-voltage triggering method for two-electrode spark switches by replacing one of the charging inductors of the Marx generator with a pulse generator. The experimental results showed that a high-voltage trigger pulse with an amplitude of 60 kV and a rising speed of 7.65 kV/100 ns was obtained from a single stackable module with a 12 V lithium battery pack as the energy source. Due to the absence of trigger electrodes, the triggering method is beneficial to extend the lifetime of switches and realize a maintenance-free repetitive operating Marx generator.