In our previous study, three novel polysaccharides, named MC-1, MC-2, and MC-3, were separated from the roots of maca (Lepidium meyenii), which is a food source from the Andes region. The structural information and immunomodulatory activity of MC-1 were then investigated. The structure and activity of MC-2 are still unknown. In this study, structural characterization revealed that MC-2 has an average molecular weight of 9.83 kDa and is composed of arabinose (20.9%), mannose (4.5%), glucose (71.9%), and galactose (2.7%). The main linkage types of MC-2 were proven to be (1→5)-α-l-Ara, (1→3)-α-l-Man, (1→)-α-d-Glc, (1→4)-α-d-Glc, (1→6)-α-d-Glc, and (1→6)-β-d-Gal by methylation and NMR analyses. Congo red assay showed that MC-2 possesses a triple-helix conformation. Immunostimulating assays indicated that MC-2 could induce M1 polarization of original macrophages and convert M2 macrophages into M1 phenotype. Although MC-2 could not shift M1 macrophages into M2, it could still inhibit inflammatory reactions induced by lipopolysaccharide. Furthermore, Toll-like receptor 2, tTll-like receptor 4, complement receptor 3, and mannose receptor were confirmed as the membrane receptors for MC-2 on macrophages. These results indicate that MC-2 could potentially be used toward hypoimmunity and tumor therapies.

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A novel peptide was extracted from wheat germ globulin and purified using ion-exchange chromatography, gel filtration chromatography, and semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC). The sequence of the peptide was found to be Glu-Cys-Phe-Ser-Thr-Ala (ECFSTA). Its immunomodulatory effects were evaluated, and the results showed that ECFSTA could enhance phagocytosis of RAW 264.7 cells and significantly increase their secretion of nitric oxide (NO), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and reactive oxygen species (ROS). ECFSTA activated macrophages mainly through the pattern recognition receptors (PRRs) of toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4), and the production of ROS simultaneously stimulated macrophages to produce TNF-α. Thus, ECFSTA could be used as an immunomodulator and might be a promising component of functional foods.

Neutrase-hydrolysates hydrolyzed from mulberry leaf proteins were separated by ion exchange chromatography, gel filtration chromatography, and semipreparative reverse-phase HPLC. Purified fractions were analyzed for their radical scavenging activity, hemolysis inhibition ability, and cellular antioxidant activity (CAA). Three new antioxidant peptides, P1 (SVL, 317 Da), P2 (EAVQ, 445 Da), and P3 (RDY, 452 Da), were obtained from the most active HPLC fraction (R1) and identified using UPLC-QTOF-MS. These three peptides were then synthesized, and their antioxidant activities were analyzed. P1 and P2 had no ability to inhibit hemolysis of erythrocytes but did show antioxidant activity on HepG2 cells. P3 showed the highest hemolysis inhibition ability (92%) and CAA value (2204 μM QE/100 g peptide). The Tyr residues at the C-terminal region play an important role in the antioxidant activity in P3. Thus, the natural peptide R1 and synthesized P3 could be used as antioxidants and might be promising components of functional foods.

A family of ambient-dried polybenzoxazine aerogels is prepared with a facile and scalable process as a high-performance polymeric aerogel with strong and robust thermomechanical properties at elevated temperatures. Those materials are inherently flame-retardant and superhydrophobic over the entire bulk density range (0.24–0.46 g cm–3). In addition, they are mechanically strong with strengths (e.g., 1 MPa at 0.24 g cm–3 at room temperature) higher than those of other high-performance aerogels of similar density, including polyimide and polyamide (Kevlar-like) aerogels as well as polymer-cross-linked X-silica and X-vanadia aerogels, at a significantly lower cost. Furthermore, unlike most other glassy polymeric materials, the maximum strength of the synthesized aerogels occurs at service temperatures slightly higher than room temperature (about 50 °C), which eliminates the possibility of any drop in strength with respect to the room temperature strength up to 150 °C at all densities. At higher temperatures (up to 250 °C), the overall performance of those aerogels is also stable and robust without any significant drop in Young’s modulus or strength levels, which makes them suitable for various industrial applications including high-performance structural and thermal protection applications as an alternative to the significantly more expensive polyimides.

Resin uptake plays a critical role in the stiffness-to-weight ratio of wind turbine blades in which sandwich composites are used extensively. This work examines the flexural properties of nominally half-inch thick sandwich composites made with polyvinyl chloride (PVC) foam cores (H60 and H80; PSC and GPC) at several resin uptakes. We found that the specific flexural strength and modulus for the H80 GPC sandwich composites increase from 82.04 to 90.70 kN Á m/kg and 6.03 to 7.13 MN Á m/kg, respectively, with 11.0% resin uptake reduction, which stands out among the four core sandwich composites. Considering reaching a high stiffness-to-weight ratio while preventing resin starvation, 32% to 38% and 40% to 45% resin uptakes are adequate ranges for the H80 PSC and GPC sandwich composites, respectively. The H60 GPC sandwich composites have lower debonding toughness than H60 PSC due to stress concentration in the smooth side skin-core interphase region. The ailure mode of the sandwich composites depends on the core stiffness and surface texture. The H60 GPC sandwich composites exhibit core shearing and bottom skincore debonding failure, while the H80 GPC and PSC sandwich composites show top skin cracking and core crushing failure. The findings indicate that an appropriate range of resin uptake exists for each type of core sandwich composite, and that within the range, a low-resin uptake leads to lighter blades and thus lower cyclic gravitational loads, beneficial for long blades.

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