Fabrication and Evaluation of PLLA Multichannel Conduits with Nanofibrous Microstructure for the Differentiation of NSCs In Vitro

Nerve conduits (NCs) with multiple longitudinally aligned channels, being mimicking the natural nerves anatomical structure, have been attracted more and more attentions. However, some specific structural parameters of a conduit that would be beneficial for further improvement of neural tissue regeneration were not comprehensively considered. Using a systematized device and combining low-pressure injection molding and thermal-induced phase separation, we fabricated 33-channel NCs (outer diameter 3.5 mm, channel diameter 200 mu m) with different well-defined microscopic features, including NCs with a nano-fibrous microstructure (NNC), NCs with microspherical pores and nano-fibrous pore walls (MNC), and NCs with a ladder-like microstructure (LNC). The porosities of these NCs were similar to 90% and were independent of the fine microstructures, whereas the pore size distributions were clearly distinct. The adsorption of bovine serum albumin for the NNC was a result of having the highest specific surface area, which was 3.5 times that of the LNC. But the mechanical strength of NNC was lower than that of two groups because of a relative high crystallinity and brittle characteristics. In vitro nerve stem cells (NSCs) incubation revealed that 14 days after seeding the NSCs, 31.32% cells were Map2 positive in the NNC group, as opposed to 15.76% in the LNC group and 23.29% in the MNC group. Addition of NGF into the culture medium, being distinctive specific surface area and a high adsorption of proteon for NNC, 81.11% of neurons derived from the differentiation of the seeded NSCs was obtained. As a result of imitating the physical structure of the basement membrane of the neural matrix, the nanofibrous structure of the NCs has facilitated the differentiation of NSCs into neurons

Supercritical carbon dioxide assisted impregnation and graft of polyamide acid into aramid fiber for formation of polar interface

Contrapose the high inertness of para-aramid fiber (AF) with high strength modulus, surface modification in a green and effective way is one of the main challenges currently faced by fiber reinforced composites engineers. In this study, AF was treated by a two-step process combining hot air treatment (250 °C, 1 h) and graft reaction of polyamide acid (PAA) assisted with supercritical carbon dioxide (scCO2). The ester group displayed on the fiber surface suggested the successful graft reaction between AF and PAA. Additionally, the auxiliary effect of scCO2 increases the surface roughness, resulting in a more uniform grafted layer on the modified fiber surface. Specifically, in the process of graft modification of AF with 5% PAA assisted by scCO2, the thickness of the grafted layer was about 100 nm. Meanwhile, a 50.15% increment of the interfacial shear strength indicated an obvious enhancements of surface adhesion. This study provides a feasible method for interfacial modification of AF, and further widens the application of scCO2 as an auxiliary process in the surface modification of AF

Oxidative Stress and Apoptosis Contributed to Nonylphenol-Induced Cell Damage in Mouse NCTC Clone 1469 Cells

Nonylphenol (NP) is considered an environmental toxicant and endocrine-disrupting compound. The present study aimed to investigate the effects of NP on NCTC Clone 1469, nonparenchymal hepatocytes, and to study the molecular basis of NP-induced liver injury. The results showed that NP decreased cell viability and induced nucleus crenulation and intracellular enzyme leakage in NCTC Clone 1469 cells. Additionally, NP-induced oxidative stress and apoptosis of NCTC Clone 1469 are accompanied by upregulating reactive oxygen species (ROS) production, increase of Bax, decrease of Bcl-2, activation of caspase-3 and caspase-12, and release of cytosolic free Ca2+ in the cells. ROS scavenger, N-acetyl-L-cysteine (NAC), prevented the intracellular enzyme leakage induced by NP. NP induced alteration of estrogen receptor- (ER-) α and ER-β expression, while ER antagonists, ICI 182,780, showed no effect on NP-induced intracellular enzyme leakage. We proposed that NP triggered cell damage via inducing oxidative stress and apoptosis in cells, but not estrogenic effect

Roles of stomata in gramineous crops growth and biomass production

Stomata, microscopic pores surrounded by two guard cells, play essential roles in the most important plant physiological processes: photosynthesis and transpiration. Unlike dicotyledons, grasses, including major gramineous crops, have distinctive dumbbell-shaped guard cells and specialized subsidiary cells, forming a more efficient stomatal complex. Stomata are capable of governing growth, development, and biomass production by means of regulating the transpiration and gas exchange process in a plant; that is, the main functions of stomata are to permit CO2 entry and control H2O movement and supply nutrients for biomass accumulation via photosynthesis. However, little is known about the roles of stomata in gramineous crops growth and biomass production. Stomatal conductance (gs) proves to be a vital aspect for high-yield potential in crops by influencing all the key traits of a crop's life cycle, particularly its biomass accumulation. Furthermore, transpiration enables stomata to stimulate biomass allocation in the phloem tissue, facilitating the translocation of assimilates and signals from the designated source to the sink, further endorsing floral transition and biomass allocation to the reproductive organs including the seed yield characteristic. This review focuses on stomatal function of gramineous crops, like rice, wheat, maize, barley, and so on. While stomata enforce majority of the essential processes in crops, their performance remains highly prone to the effects of unfavorable environmental conditions. Thus, manipulation of stomatal regulation is useful for the promotion of crop growth and biomass production