Interface Strengthening of α-Mg/C14–Mg2Ca Eutectic Alloy

This study investigates the effect of the α/C14 interface on the creep strength of α-Mg/C14–Mg2Ca eutectic alloy at 473 K under a stress of 40 MPa. The α/C14 interface is composed of terraces and steps, with terraces parallel to the (1101)α pyramidal plane of the α-Mg lamellae and to the (1120)C14 columnar plane of the C14–Mg2Ca lamellae. The creep curves of the alloy exhibit three stages: a normal transient creep stage, a minimum creep rate stage, and an accelerating stage. The minimum creep rate is proportional to the lamellar spacing, indicating that the α/C14 lamellar interface plays a creep-strengthening role. In the high-resolution transmission electron microscopy image captured of the specimen after the creep test, <a> dislocations can be mainly seen within the soft α-Mg lamellae, and they are randomly distributed at the α/C14 interface. In contrast, dislocations are rarely introduced in the hard C14–Mg2Ca lamellae. It is deduced that the α/C14 interface presents a barrier to dislocation gliding within the α-Mg lamellae and does not help rearrange the dislocations.

Lentinan-Based Oral Nanoparticle Loaded Budesonide With Macrophage-Targeting Ability for Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a global, chronic, and refractory disease. Corticosteroids are first-line drugs for the treatment of UC but also cause adverse side effects. Budesonide (BUD), a corticosteroid with relatively low side effects, has been approved by the Food and Drug Administration for use as enteric capsules (Entocort EC) for the treatment of inflammatory bowel disease (IBD). However, this formulation lacks specific targeting ability to UC lesions. Herein, we describe the development of an advanced macrophage-targeted oral lentinan (LNT)–based nanoparticles (NPs) loaded BUD for treatment of UC. Briefly, LNT was used as a food source and natural carrier to load BUD by a simple solvent evaporation method to form LNT/BUD-NPs. LNT showed good loading capacity with high encapsulation and loading efficiencies to BUD of approximately 92.19 and 9.58%, respectively. Evaluation of the gastric stability of LNT/BUD-NPs indicated that LNT could effectively protect BUD from gastric acid and digestive enzymes. The release behavior and transmission electron microscopy image of LNT/BUD-NPs in the intestinal content of mice confirmed that intestinal flora can promote BUD release from LNT. Moreover, evaluation of cellular uptake showed that LNT/BUD-NPs could specifically target macrophages and enhance their uptake rate via the Dectin-1 receptor. In biodistribution studies, LNT/BUD-NPs were able to efficiently accumulate in the inflamed colon of mice. As expected, LNT/BUD-NPs could significantly alleviate inflammation by inhibiting the TLR4/MyD88/NF-κB signaling pathway. Therefore, LNT/BUD-NPs have the advantages of good gastric stability, release mediated by mouse intestinal content, macrophage-targeting, and anti-UC effects. These advantages indicate LNT-based NPs are a promising oral drug delivery system for UC therapy.

Investigating the dielectric properties of barium titanate nanocomposites using transmission electron microscopy image processing

Barium titanate (BTO) is a ferroelectric perovskite material used in energy storage applications because of its high dielectric constant. A previous study showed that the dielectric constant for BTO nanoparticles drastically increases to over 15,000 at a particle size of 70 nm. This result is highly contested, but its implications to energy storage motivated our investigation into the dielectric constants of BTO nanoparticles that are incorporated into a polymer matrix. We developed a novel method of using image processing techniques on transmission electron microscope images of BTO-polymer nanocomposites. Data on the positions, shapes, sizes, and orientations of BTO nanoparticles were used to build more realistic computational models that simulate the dielectric behavior of the nanocomposites. Here, we investigate the relationship between regions of enhanced electric field and the composite dielectric constant.