Bio-based polymeric materials from vegetable oils

Vegetable oils have been utilized in developing various types of bio-based materials in my research work. Bio-based polyhydroxy fatty acids have been subject to ring-opening epoxidized soybean oil with alkaline catalyst DBU to generate polyols with varying OH numbers. Polyurethane films were obtained using these polyols polymerized with isophrone diisocyanates. The polyhydroxy fatty acids were also used as internal emulsifiers in anionic polyurethane dispersion synthesis due to the presence of carboxylic acid groups in their structures. In addition, acrylated epoxidized soybean oil was involved in another project. 2-methyl aziridine was added to acrylic groups via Michael addition mechanism under mild conditions. The resulting aziridine-containing compound could be polymerized with bio-based polyacids rapidly at room temperature. Plus, thermal polymerization of soybean oil has been studied. The heat-bodied soybean oils were subject to ozonolysis followed by reduction in order to produce polyols with primary hydroxyls, which are relatively reactive. The principle of the research is to develop products with considerably high bio-content. The soaring price of petroleum has become a global issue so that industry and academia have been seeking bio-renewable substitutions which can be potentially converted to versatile products that have comparable properties to petroleum-based merchandise

A Two Step Synthesis Route of WC Nanopowders

Here, a novel molten salt route to synthesize ceramic WC nanopowders was presented. Compared to the traditional synthesis procedures, this method is relatively low cost involving two-step synthesis route. In the argon atmosphere at 650 oC, the powders were the mixed WC and W2C phases. These synthesized powders were transferred to a small crucible (30 mL) containing molten salt, which were put into a 500 mL crucible with some carbon powder in it as reducing atmosphere, followed by maintaining the reaction temperature at 1100 °C for 1 h. The phase purity and composition were characterized by the powder X-ray diffractometer (XRD). It was found that W2C was transformed thoroughly into WC, which indicated the successful synthesis of WC powders using this method. The mechanism of the reaction process in molten salt has been discussed finally. The thermogravimetric analysis indicated that the as-prepared samples showed good thermal stability and oxidation resistance in high temperature. The methodology reported in this work was fundamentally important, which may find potential industrial applications

Enhancing Low-Precision Sampling via Stochastic Gradient Hamiltonian Monte Carlo

Low-precision training has emerged as a promising low-cost technique to enhance the training efficiency of deep neural networks without sacrificing much accuracy. Its Bayesian counterpart can further provide uncertainty quantification and improved generalization accuracy. This paper investigates low-precision sampling via Stochastic Gradient Hamiltonian Monte Carlo (SGHMC) with low-precision and full-precision gradient accumulators for both strongly log-concave and non-log-concave distributions. Theoretically, our results show that, to achieve $\epsilon$-error in the 2-Wasserstein distance for non-log-concave distributions, low-precision SGHMC achieves quadratic improvement ($\widetilde{\mathbf{O}}\left({\epsilon^{-2}{\mu^*}^{-2}\log^2\left({\epsilon^{-1}}\right)}\right)$) compared to the state-of-the-art low-precision sampler, Stochastic Gradient Langevin Dynamics (SGLD) ($\widetilde{\mathbf{O}}\left({{\epsilon}^{-4}{\lambda^{*}}^{-1}\log^5\left({\epsilon^{-1}}\right)}\right)$). Moreover, we prove that low-precision SGHMC is more robust to the quantization error compared to low-precision SGLD due to the robustness of the momentum-based update w.r.t. gradient noise. Empirically, we conduct experiments on synthetic data, and {MNIST, CIFAR-10 \& CIFAR-100} datasets, which validate our theoretical findings. Our study highlights the potential of low-precision SGHMC as an efficient and accurate sampling method for large-scale and resource-limited machine learning

A Common Variant in CLDN14 is Associated with Primary Biliary Cirrhosis and Bone Mineral Density.

Primary biliary cirrhosis (PBC), a chronic autoimmune liver disease, has been associated with increased incidence of osteoporosis. Intriguingly, two PBC susceptibility loci identified through genome-wide association studies are also involved in bone mineral density (BMD). These observations led us to investigate the genetic variants shared between PBC and BMD. We evaluated 72 genome-wide significant BMD SNPs for association with PBC using two European GWAS data sets (n = 8392), with replication of significant findings in a Chinese cohort (685 cases, 1152 controls). Our analysis identified a novel variant in the intron of the CLDN14 gene (rs170183, Pfdr = 0.015) after multiple testing correction. The three associated variants were followed-up in the Chinese cohort; one SNP rs170183 demonstrated consistent evidence of association in diverse ethnic populations (Pcombined = 2.43 × 10(-5)). Notably, expression quantitative trait loci (eQTL) data revealed that rs170183 was correlated with a decline in CLDN14 expression in both lymphoblastoid cell lines and T cells (Padj = 0.003 and 0.016, respectively). In conclusion, our study identified a novel PBC susceptibility variant that has been shown to be strongly associated with BMD, highlighting the potential of pleiotropy to improve gene discovery

STUDY ON ANTICANCER EFFECT OF SYNTHETIC BIOGENIC SOURCE OF GERMACRENE A

Objective: Based on obtaining germacrene A, which is the analogue of synthetic β-elemene, by means of synthetic biology，this experiment aims to explore the anti-tumor effect of germacrene A. Results: After administration, the volume of T24 cells was significantly reduced. The shape of the T24 cells gradually changed from wedge-shaped and polygonal to round, and the T24 cells soon fell off, atrophied and disintegrated. After Tet blue staining, a large number of T24 cells after administration were observed to be dead; It was found by means of MTT assay that T24 cells were inhibited to varying degrees by the effects of different concentrations of germacrene A. Conclusion: The above experimental results show that the synthetic biological source of germacrene A has obvious inhibitory effect on bladder cancer T24 cells, and this effect has obvious time and concentration dependence. Keywords：Germacrene A; Synthetic drugs; Antitumor; β-elemen

Mucosal-Associated Invariant T Cells Improve Nonalcoholic Fatty Liver Disease Through Regulating Macrophage Polarization

Mucosal-associated invariant T (MAIT) cells, a novel population of innate-like lymphocytes, have been involved in various inflammatory and autoimmune diseases. However, their role in the development of nonalcoholic fatty liver disease (NAFLD) remains unclear. In this study, we investigated the alterations of phenotype and immunological function of MAIT cells in NAFLD. Analysis of PBMCs in 60 patients with NAFLD and 48 healthy controls (HC) revealed that circulating MAIT cell frequency decreased in NAFLD, especially in the patients with higher serum levels of γ-glutamyl transferase or total triglyceride. Functional alterations of circulating MAIT cells were also detected in NAFLD patients, such as the increased production of IL-4 whereas the decreased production of IFN-γ and TNF-α. Furthermore, elevated expression of CXCR6 was observed in circulating MAIT cells of patients. Meanwhile, we found an increased number of MAIT cells in the livers of NAFLD, and the number was even greater in patients with higher NAFLD activity score. Moreover, activated MAIT cells induced monocytes/macrophages differentiation into M2 phenotype in vitro. Additionally, MAIT cells were enriched and displayed Th2 type cytokines profile in livers of wild type mice fed with methionine and choline deficient diet (MCD). Notably, mice deficient of MAIT cells exhibited more severe hepatic steatosis and inflammation upon MCD, accompanied with more CD11c+ proinflammatory macrophages (M1) and less CD206+ anti-inflammatory macrophages (M2) in livers. Our results indicate that MAIT cells protect against inflammation in NAFLD through producing regulatory cytokines and inducing anti-inflammatory macrophage polarization, which may provide novel therapeutic strategies for NAFLD

Bio-based polymeric materials from vegetable oils

Vegetable oils have been utilized in developing various types of bio-based materials in my research work. Bio-based polyhydroxy fatty acids have been subject to ring-opening epoxidized soybean oil with alkaline catalyst DBU to generate polyols with varying OH numbers. Polyurethane films were obtained using these polyols polymerized with isophrone diisocyanates. The polyhydroxy fatty acids were also used as internal emulsifiers in anionic polyurethane dispersion synthesis due to the presence of carboxylic acid groups in their structures. In addition, acrylated epoxidized soybean oil was involved in another project. 2-methyl aziridine was added to acrylic groups via Michael addition mechanism under mild conditions. The resulting aziridine-containing compound could be polymerized with bio-based polyacids rapidly at room temperature. Plus, thermal polymerization of soybean oil has been studied. The heat-bodied soybean oils were subject to ozonolysis followed by reduction in order to produce polyols with primary hydroxyls, which are relatively reactive. The principle of the research is to develop products with considerably high bio-content. The soaring price of petroleum has become a global issue so that industry and academia have been seeking bio-renewable substitutions which can be potentially converted to versatile products that have comparable properties to petroleum-based merchandise.</p

Rapid room-temperature polymerization of bio-based multiaziridine-containing compounds

Successful Michael addition under mild reaction conditions resulted in the grafting of 2-methyl aziridine onto acrylated epoxidized soybean oil, and the aziridine content was titrated as 0.00413 mol g−1. Multiaziridine-containing acrylated epoxidized soybean oil (AESO-AZ) was then subjected to rapid room-temperature polymerization with succinic acid, citric acid, and an isosorbide-based diacid, respectively. The polyacids were added to AESO-AZ at stoichiometric ratios. The resulting polymeric materials were cast into films in order to investigate their thermo-mechanical properties. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and tensile stress–strain tests were performed. The glass transition temperatures (Tg) of the samples suggested that increased functionality of the carboxylic acid groups in the polyacids may have effectively increased Tg, while the rigid rings in isosorbide did not have significant impact on Tg. This work illustrates the feasibility of synthesizing bio-based multiaziridine-containing compounds that can be used as the monomer for rapid polymerization with bio-based polyacids at ambient temperature

Anionic waterborne polyurethane dispersion from a bio-based ionic segment

Anionic waterborne polyurethane dispersions were prepared from ring-opening epoxidized linseed oil with glycol and hydrochloric acid followed by saponification, step-growth polymerization, and ionomerization. When the intermediate bio-based polyhydroxy fatty acid has an OH functionality of 4.8, the fatty acid can crosslink, and its carboxylic groups are able to provide surface charge for the stabilization of the resulting polymer in the water phase. Two novel anionic waterborne polyurethane dispersions, one with and one without additional castor oil, were successfully prepared and compared to a conventional control sample. Films from the polyurethane dispersions were obtained by casting the dispersions into molds and subsequently characterized by differential scanning calorimetry, dynamic mechanical analysis, ethanol absorption and uptake, thermogravimetric analysis, and tensile stress–strain tests. The castor oil containing polymer displayed a decrease in glass transition temperature, tensile strength, and Young's modulus, but an increase in elongation compared to the control sample. The sample without the castor oil behaved like a brittle, glassy material with higher Young's modulus and lower ductility because of its relatively high crosslinking density. This work proves the viability of incorporating vegetable-oil based polyhydroxy fatty acids as ionic segments into anionic waterborne polyurethane dispersions