An Efficient Dispersive Agent — KCl for Ultrasonic Preparation of Microfibrillated Cellulose (MFC)

The suitability of saturated salt solutions as a dispersive agent for preparing microfibrillated cellulose (MFC) from bamboo processing residue through ultrasonication was evaluated. The effect of pure water and KCl solution on the rheological behavior and morphologies of prepared MFC were compared. The results show that the viscosity of MFC suspension dispersed in KCl solution decreases by several orders of magnitude compared to the water counterpart. SEM images demonstrate that MFCs with comparable quality can be prepared using either pure water or KCl solution as a dispersive agent. A high concentration of bamboo processing residue (~2 wt.%) dispersed in salt solutions was found to possess comparable viscosity with a low concentration of MFC suspension (~0.5 wt.%) dispersed in water. This indicates that the application of salt solutions as dispersive agents in ultrasonication has great potential to improve the productivity of MFC prepared from plant materials

The Furfurylation of Wood: A Nanomechanical Study of Modified Wood Cells

Furfurylation of wood is of interest worldwide as an environmentally friendly modification process. It is widely assumed that low-molecular weight furfuryl alcohol (FA) can penetrate into wood cells and polymerize in-situ during the process, resulting in substantial improvement in the physical-mechanical properties and durability of wood. In this study, confocal laser scanning microscopy (CLSM) was used to visualize the microscopic distribution of polymerized FA resin in the Masson pine wood cavities, and a Nanoindenter was used to probe the mechanical properties of modified wood cells. The effects of catalysts (maleic anhydride and a mixed organic acid catalyst), FA concentration, curing time, and curing temperature on the nanomechanical properties of wood cell walls were investigated. An improvement in the indentation modulus and hardness of modified wood cells demonstrated indirectly but strongly that FA indeed penetrated wood cells during the modification process. Based on the results of the cell wall nanoindentation test, a combination of 50% furfuryl alcohol, 8 h curing time, and 95 °C curing temperature were proposed as the starting processing parameters for the development of a more practical and effective wood furfurylation process using a mixed organic acid catalyst

Probabilistic Modeling for Cementitious Materials Based on Data of Nanoindentation

By introducing probabilistic modeling approaches, the interface transition zone (ITZ) and the bulk paste (BP) of concrete are investigated on the basis of the nanoindentation results, especially with respect to the relationship between the microstructure and mechanical properties of cementitious materials. The investigation of the probability density function (PDF) of the random field for nanoindentation properties revealed that the same properties of the ITZ and the BP usually yield the same PDF, which was elaborated from different points of view. Specifically, a log-normal distribution was best for nanoindentation hardness, whereas the Weibull distribution and gamma distribution were much more suitable for the nanoindentation modulus of both the ITZ and the BP. According to the comparative study of the correlation structure, both the ITZ and BP obeyed the exponential correlation structure associated with a first-order autoregressive process, and basically exhibited a similar scale of fluctuation. Furthermore, the scales of fluctuation were found to be directly related to the clinker size and the distance between clinkers. Our work provides a new approach to stochastically modeling cementitious materials, where the content of hydration products controls the mean values of nano-properties, the indentation property dominates the PDF, and the nano-topological structure governs the correlation structure

Increased polyphenols and antioxidant activity of rice bean (Vigna umbellata L.) sprouts induced by Methyl Jasmonate: the promotion effect of Methyl Jasmonate on rice bean sprouts

Abstract Rice bean (Vigna umbellata L.) sprouts are richer in metabolites and biological activities after germination. The total polyphenol and total flavonoid contents were analyzed during the sprouting process. The antioxidant activities of the sprouts were tested using 1,1-diphenyl-2- picrylhydrazyl radical (DPPH) screening assay. To determine the reason for increased activity, quantitative analysis of 8 flavonoids, in the germination process of methyl jasmonate (MeJA)-treated and control groups, was performed using high-performance liquid chromatography coupled with diode array detection (HPLC/DAD) and partial least squares discriminant analysis (PLS/DA). The metabolites in MeJA-treated beans shows that addition of 100.0 μmol MeJA significantly increased the total flavonoid and polyphenol contents during the sprouting process. DPPH screening assay and analytical results show that MeJA has a significant influence on the production of secondary metabolites in sprouts between the 4th and 6th days, thereby inducing increased antioxidant activity. Flavonoids rutin, kaempferol-3-O-rutinoside, daidzin, and genistin are further identified as the main contributors to the increased DPPH screening activity

Increased antioxidant activity and polyphenol metabolites in methyl jasmonate treated mung bean (Vigna radiata) sprouts

Abstract Mung bean sprouts are a popular health food both in China and worldwide. We determined the optimal concentration of exogenous methyl jasmonate (MeJA) for the promotion of the sprouting in mung beans (Vigna radiata). The 1,1-diphenyl-2- picrylhydrazyl radical (DPPH) scavenging test showed that MeJA application resulted in significantly improved antioxidant capacity in the sprouts 72 h later. Measurement of total polyphenols in MeJA-treated beans from 0 to 168 h, using Folin–Ciocalteu colorimetry, showed that the polyphenols changing was significantly correlated with antioxidant activity. The main polyphenols isovitexin, kaempferol-3-O-rutinoside, daidzein, genistein, isoquercitrin, p-coumaric acid, and caffeic acid were quantified using high-performance liquid chromatography (HPLC/QqQ MS) and partial least squares discriminant analysis (PLS-DA). MeJA promoted the production of polyphenols, metabolites, and antioxidants in the sprouts; therefore, its use may allow sprouts to be prepared more quickly or increase their nutritional value

Reprogramming immunosuppressive myeloid cells facilitates immunotherapy for colorectal cancer

Abstract Immune checkpoint blockade (ICB) has a limited effect on colorectal cancer, underlining the requirement of co‐targeting the complementary mechanisms. Here, we identified prostaglandin E2 (PGE2) receptor 4 (EP4) as the master regulator of immunosuppressive myeloid cells (IMCs), which are the major driver of resistance to ICB therapy. PGE2‐bound EP4 promotes the differentiation of immunosuppressive M2 macrophages and myeloid‐derived suppressor cells (MDSCs) and reduces the expansion of immunostimulated M1 macrophages. To explore the immunotherapeutic role of EP4 signaling, we developed a novel and selective EP4 antagonist TP‐16. TP‐16 effectively blocked the function of IMCs and enhanced cytotoxic T‐cell‐mediated tumor elimination in vivo. Cell co‐culture experiments revealed that TP‐16 promoted T‐cell proliferation, which was impaired by tumor‐derived CD11b+ myeloid cells. Notably, TP‐16 and anti‐PD‐1 combination therapy significantly impeded tumor progression and prolonged mice survival. We further demonstrated that TP‐16 increased responsiveness to anti‐PD‐1 therapy in an IMC‐related spontaneous colorectal cancer mouse model. In summary, this study demonstrates that inhibition of EP4‐expressing IMCs may offer a potential strategy for enhancing the efficacy of immunotherapy for colorectal cancer