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107. Synthesis of Structure-Controlled Polyborosiloxanes and Investigation on Their Viscoelastic Response to Molecular Mass of Polydimethylsiloxane Triggered by Both Chemical and Physical Interactions

Author

Wang Wen-tao, Tang Miao, Wang Zhi-Gang, and XU Donghua

Subjects
Materials science, Polydimethylsiloxane, Molecular mass, General Chemical Engineering, Analytical chemistry, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Industrial and Manufacturing Engineering, Viscoelasticity, 0104 chemical sciences, Chemical kinetics, chemistry.chemical_compound, chemistry, Rheology, Fourier transform infrared spectroscopy, 0210 nano-technology, Spectroscopy, Elastic modulus
Abstract

A series of polyborosiloxanes (PBSs) was synthesized by mixing hydroxy-terminated polydimethylsiloxanes (PDMS) and boric acid (BA) in toluene at 120 °C. The molecular masses of selected PDMS precursors were in a wide range, covering from below up to far above the critical entanglement molecular mass of PDMS. The reaction kinetics was followed by using Fourier transform infrared (FTIR) spectroscopy. Unreacted BA was removed from raw PBSs after the reactions. The influence of molecular mass of PDMS precursors on the rheological property of PBSs was explored by dynamic oscillatory frequency sweeps. The results showed that the plateau elastic moduli of PBSs were highly dependent on the molecular mass of PDMS precursors. The plateau elastic moduli of PBSs decreased at first and then increased with increasing molecular mass of PDMS precursors. PBS1 and PBS2 prepared from unentangled PDMS precursors showed sufficient fits by using the two-mode Maxwell model, whereas PBS3 to PBS6 prepared from highly entangled PD...

Published
2016

110. Rheological study on the cure kinetics of two-component addition cured silicone rubber

Author

Dou Yanli, Guan Dongbo, Liu Xin-chun, Lou Bo, Yao Weiguo, Xu Donghua, and Cai Zhongyi

Subjects
Addition reaction, Materials science, Order of reaction, Polymers and Plastics, General Chemical Engineering, Diffusion, Organic Chemistry, Thermodynamics, 02 engineering and technology, Activation energy, 010402 general chemistry, 021001 nanoscience & nanotechnology, Silicone rubber, 01 natural sciences, Chemical reaction, 0104 chemical sciences, Reaction rate, chemistry.chemical_compound, Reaction rate constant, chemistry, Composite material, 0210 nano-technology
Abstract

The cure kinetics for two-component silicone rubber formed by addition reaction was studied by the rheological method. The influence of reaction temperature (T) on the cure kinetics was explored in detail. It was observed that the data of gel time (tgel, i.e. the time when the reaction reaches the gel point) or a specific reaction time (tnc) (defined as the reaction time before which time the influence of confinement of network on the diffusion of reaction components can be neglected) versus T obey certain functional relationship, which was well explained by the cure kinetics model of thermoset network. The cure kinetics for the two-component silicone rubber can be well fitted by the Kamal-Sourour(autocatalyst) reaction model rather than Kissinger model. When the reaction time was before or equal to tnc, the reaction order obtained by the Kamal-Sourour reaction model was 2, which was consistent with the reaction order inferred from the two components chemical reaction when the diffusion of reaction components was not influenced by the formed cross-linked polymer network. When the reaction time was larger than tnc, such as to the end of reaction (te), the influence of confinement of network on the diffusion of reaction components cannot be neglected, and the reaction order obtained by the Kamal-Sourour reaction model was larger than 2. It was concluded that the confinement effect of network had a greater influence on the cure kinetics of the silicone rubber. The reaction rate constants (kr) under different temperatures were also determined by Kamal-Sourour reaction model. The activation energy (E) for the two-component silicone rubber was also calculated from the results of lntgel, lntnc, and lnkr versus 1/T, respectively. The three values of E were close, which indicated that above analyses were self-consistent.

Published
2016

111. Aberrant Methylation of miR-34b and IL-12B mRNA Promoters Contributes to the Reduced Severity of Ankylosing Spondylitis.

Author

Meng, Shan, Fan, Shaoguang, Li, Yanmei, Xu, Donghua, Ma, Xiufen, Su, Yuhua, Liu, Yajing, Guan, Chunxiao, and Shu, Qiang

Subjects
ANKYLOSING spondylitis, METHYLGUANINE, METHYLATION, DNA methylation, MESSENGER RNA, C-reactive protein, TUMOR suppressor genes
Abstract

DNA methylation of Interleukin-12B (IL-12B) and miR-34b was proved to affect the expression of IL-12B and miR-34b, which were found to be involved in the pathogenesis of ankylosing spondylitis (AS). However, the molecular mechanisms underlying the role of IL-12B and miR-34b in AS remain to be explored. AS patients were divided into four groups according to their status of DNA methylation of miR-34b and IL-12B by bisulfite sequencing: HYPER-miR-34b + HYPO-IL-12B, HYPER-miR-34b + HYPER-IL-12B, HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups. Functional indicators were examined for patients with different status of DNA methylation in their miR-34b and IL-12B promoters. QPCR was performed to examine the expression of miR-34b and IL-12B mRNA under different conditions. ELISA was used to measure the expression of IL-12B p40 in the peripheral blood. Western blot was used to analyze the expression of IL-12B proteins. Luciferase assay was carried out to explore the suppressive role of miR-34b in IL-12B expression. The level of Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) was gradually increased in HYPER-miR-34b + HYPO-IL-12B,HYPER-miR-34b + HYPER-IL-12B,HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups, whereas the levels of Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Metrology Index (BASMI) were significantly elevated in the HYPO-miR-34b + HYPO-IL-12B group and diminished in the HYPER-miR-34b + HYPO-IL-12B group. The expression of miR-34b in the PBMCs and peripheral blood was remarkably higher in the HYPER-miR-34b + HYPO-IL-12B and HYPER-miR-34b + HYPER-IL-12B groups, whereas the expression of IL-12B was gradually decreased in the HYPER-miR-34b + HYPO-IL-12B, HYPER-miR-34b + HYPER-IL-12B, HYPO-miR-34b + HYPER-IL-12B and HYPO-miR-34b + HYPO-IL-12B groups. Luciferase assays with the transfection of miR-34b precursors suggested that miR-34b strongly suppressed the expression of IL-12B in THP-1 cells. In conclusion, our study demonstrated that hypermethylated miR-34b promoter led to evident upregulation of miR-34b, thus inhibiting the expression of IL-12B and alleviated the severity of ankylosing spondylitis by reducing the levels of factors including ASDAS-CRP, BASFI and BASMI. [ABSTRACT FROM AUTHOR]

Published
2021
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118. The variants at FLNAand FLNBcontribute to the susceptibility of hypertension and stroke with differentially expressed mRNA

Author

Liu, Chunlan, Tang, Wuzhuang, Zhao, Hailong, Yang, Song, Ren, Zhanyun, Li, Jie, Chen, Yanchun, Zhao, Xianghai, Xu, Donghua, Zhao, Yanping, and Shen, Chong

Abstract

Background: Filamin A and filamin B were involved in vascular development and remodeling. Herein, it is important to explore the associations of FLNAand FLNBvariants with hypertension and stroke. Methods: The associations of two single-nucleotide polymorphisms (SNPs) at FLNAand five SNPs at FLNBwith hypertension and stroke were examined in two case-control studies and a cohort study in Chinese Han population. Risks were estimated as odds ratio (OR) and hazard ratio (HR) by Logistic and Cox regression analysis respectively. In addition, filamin B, FLNAand FLNBmRNA expression were measured. Results: In the case-control study of hypertension, FLNArs2070816 (CT + TT vs. CC) and rs2070829 (CG + GG vs. CC) were significantly associated with hypertension in <55 years group (OR = 1.338, P= 0.018; OR = 1.615, P= 0.005) and FLNBrs839240 (AG + GG vs. AA) was significantly associated with hypertension in females (OR = 0.828, P= 0.041) and nonsmokers (OR = 0.829, P= 0.020). In the follow-up study, rs2070829 GG genotype carriers presented a higher risk of hypertension than CC/CG in males (HR = 1.737, P= 0.014) and smokers (HR = 1.949, P= 0.012). In the case-control study of stroke, FLNBrs1131356 variation was significantly associated with ischemic stroke (IS) and intracerebral hemorrhage (ICH), ORsof additive model were 1.342 and 1.451, with Pvalues of 0.001 and 0.007. The FLNA transcript 2, FLNB transcript 3, transcript 4 mRNA, and filamin B expression levels were significantly different between IS cases and hypertension controls and among the genotypes of rs839240 in hypertensive individuals (P< 0.05). Conclusions: Our findings support the genetic contribution of FLNAand FLNBto hypertension, and stroke with differentially mRNA expression.

Published
2021
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134. Predicting the shift of threatened ungulates’ habitats with climate change in Altun Mountain National Nature Reserve of the Northwestern Qinghai-Tibetan Plateau

Author

Wu, Xiaoyu, primary, Dong, Shikui, additional, Liu, Shiliang, additional, Su, Xukun, additional, Han, Yuhui, additional, Shi, Jianbin, additional, Zhang, Yong, additional, Zhao, Zhenzhen, additional, Sha, Wei, additional, Zhang, Xiang, additional, Gao, Feng, additional, and Xu, Donghua, additional

Published
2017
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140. Serum Uric Acid Increases Risk of Cancer Incidence and Mortality: A Systematic Review and Meta-Analysis

Author

Yan, Shushan, Zhang, Pengjun, Xu, Wei, Liu, Yuqing, Wang, Bin, Jiang, Tao, Hua, Changjiang, Wang, Xuan, Xu, Donghua, and Sun, Beicheng

Subjects
Article Subject
Abstract

SUA is a potent antioxidant and thus may play a protective role against cancer. Many epidemiological studies have investigated this hypothesis but provided inconsistent and inconclusive findings. We aimed to precisely elucidate the association between SUA levels and cancer by pooling all available publications. Totally, 5 independent studies with 456,053 subjects and 12 with 632,472 subjects were identified after a comprehensive literature screening from PubMed, Embase, and Web of Science. The pooled RRs showed that individuals with high SUA levels were at an increased risk of total cancer incidence (RR=1.03, 95% CI 1.01–1.05, P=0.007). Positive association between high SUA levels and total cancer incidence was observed in males but not females (for men: RR=1.05, 95% CI 1.02–1.08, P=0.002; for women, RR=1.01, 95% CI 0.98–1.04, P=0.512). Besides, high SUA levels were associated with an elevated risk of total cancer mortality (RR=1.17, 95% CI 1.04–1.32, P=0.010), particularly in females (RR=1.25, 95% CI 1.07–1.45, P=0.004). The study suggests that high SUA levels increase the risk of total cancer incidence and mortality. The data do not support the hypothesis of a protective role of SUA in cancer.

Published
2015
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141. Increased Risk of Cancer in relation to Gout: A Review of Three Prospective Cohort Studies with 50,358 Subjects

Author

Wang, Weijie, Xu, Donghua, Wang, Bin, Yan, Shushan, Wang, Xiaochen, Yin, Yin, Wang, Xuehao, Sun, Beicheng, and Sun, Xiaoyang

Subjects
musculoskeletal diseases, congenital, hereditary, and neonatal diseases and abnormalities, Article Subject, nutritional and metabolic diseases
Abstract

Gout is a common inflammatory disease characterized by acute arthritis and hyperuricemia. A number of epidemiological studies have suggested the critical role of gout in carcinogenesis. The aim of this study was to estimate the association between gout and cancer risk by meta-analysis of all relevant studies published to date. A comprehensive literature search in PubMed and Embase databases from their inception up to July 1, 2014, was performed to identify eligible studies. The strength for relationship between gout and the risk of different cancers was evaluated by calculating pooled relative risks (RRs) with 95% confidence intervals (95% CIs). All analyses were carried out by STATA 12.0 software. Gout patients were at an increased risk of cancer, particularly urological cancers, digestive system cancers, and lung cancer. No such significant association between gout and the risk of breast or brain cancers was observed. Sensitivity analysis did not materially alter the pooled results. Gout is a risk factor of cancer, particularly that of urological cancers, digestive system cancers, and lung cancer. The pooled data further support the hypothesis of a link between gout and carcinogenesis.

Published
2015
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143. MiRNA‐548c‐5p downregulates inflammatory response in preeclampsia via targeting PTPRO.

Author

Wang, Zengfang, Wang, Pingping, Wang, Zengyan, Qin, Zhihao, Xiu, Xia, Xu, Donghua, Zhang, Xiaozhen, and Wang, Yingliang

Subjects
PREECLAMPSIA, PREGNANCY complications
Abstract

Preeclampsia is a serious complication of pregnancy and leads to maternal hypertension and proteinuria. It remains a major health problem for mothers and babies across the world due to high maternal and fetal morbidity and mortality. Accumulated data have implicated the critical role of microRNA in preeclampsia. However, to date, the role of miR‐548c‐5p in preeclampsia remains vaguely understood. In this study, we first elucidate the role of miR‐548c‐5p and its underlying molecular mechanism in preeclampsia. Compared with healthy controls, miR‐548c‐5p was obviously downregulated in serum exosomes and placental mononuclear cells in patients with preeclampsia. Nonetheless, PTPRO was significantly upregulated and negatively associated with miR‐548c‐5p in placental mononuclear cells in patients with preeclampsia. PTPRO was a target of miR‐548c‐5p. PTPRO was downregulated in the miR‐548c‐5p‐overexpressed macrophages. In addition, miR‐548c‐5p could inhibit the proliferation and activation of LPS‐stimulated macrophages, as evidenced by decreased levels of inflammatory cytokines (IL‐12 and TNF‐α) and less nuclear translocation of pNF‐κB in pTHP1 cells. MiR‐548c‐5p acts as an anti‐inflammatory factor in preeclampsia. The axis of miR‐548c‐5p/PTPRO/NF‐κB may provide novel targets for the diagnosis and treatment of preeclampsia. MiR‐548c‐5p was obviously downregulated in preeclampsia. MiR‐548c‐5p inhibited the proliferation and inflammation of pTHP1 macrophages dependent on the NF‐κB signaling pathway. [ABSTRACT FROM AUTHOR]

Published
2019
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145. Exosome‐encapsulated miR‐6089 regulates inflammatory response via targeting TLR4.

Author

Xu, Donghua, Song, Meiyan, Chai, Chunxiang, Wang, Jinghua, Jin, Chengwen, Wang, Xiaodong, Cheng, Min, and Yan, Shushan

Subjects
*EXOSOMES, *MICRORNA, *GENETIC regulation, *INFLAMMATION, *AUTOIMMUNE diseases, *TOLL-like receptors
Abstract

Exosome‐encapsulated microRNAs (miRNAs) have been identified as potential biomarkers in autoimmune diseases. However, little is known about the role of exosome‐delivered miRNAs in rheumatoid arthritis (RA). In this study, we investigated the profile of specific exosomal miRNAs by microarray analysis of serum exosomes from three patients with RA and three healthy controls. Quantitative real‐time PCR (qRT‐PCR) was performed to validate the aberrantly expressed exosomal miRNAs. A total of 20 exosome‐encapsulated miRNAs were identified to be differently expressed in the serum of patients with RA compared with controls. Interestingly, we found that exosome‐encapsulated miR‐6089 was significantly decreased after validation by qRT‐PCR in serum exosomes from 76 patients with RA and 20 controls. Besides, miR‐6089 could inhibit lipopolysaccharide (LPS)‐induced cell proliferation and activation of macrophage‐like THP‐1 cells. TLR4 was a direct target for miR‐6089. MiR‐6089 regulated the generation of IL‐6, IL‐29, and TNF‐α by targetedly controlling TLR4 signaling. In conclusion, exosome‐encapsulated miR‐6089 regulates LPS/TLR4‐mediated inflammatory response, which may serve as a novel, promising biomarker in RA. TLR4 is a direct target for miR‐6089. MiR‐6089 regulates the generation of IL‐6, IL‐29, and TNF‐α by targetedly controlling the TLR4 signaling. [ABSTRACT FROM AUTHOR]

Published
2019
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146. Development of Novel Binary and Multi-Component Bulk Metallic Glasses

Author

Xu, Donghua, Xu, Donghua, Xu, Donghua, and Xu, Donghua

Abstract

Bulk Metallic Glasses (BMGs) have been drawing increasing attention in recent years due to their scientific and engineering significance. A great deal of effort in this area has been devoted to developing BMGs in different alloy systems. BMGs based on certain late transition metals (e.g. Fe, Co, Ni, Cu) have many potential advantages over those based on early transition metals. These include even higher strength and elastic modulii, and lower materials cost, to name a few, which are highly preferable for a broad application of BMGs as engineering materials. Nevertheless, these ordinary-late-transition-metal-based BMGs generally have quite limited glass-forming ability (GFA). In particular, for the Ni-based and Cu-based alloys reported prior to this research, the maximum casting thickness allowed to retain their amorphous structures is only ~2 mm (or lower) and ~5 mm (or lower), respectively. During this research it was first found that certain quinary Ni-based alloys in the Ni-Cu-Ti-Zr-Al system can be cast into 5 mm diameter amorphous rods. This critical casting thickness is the highest for any reported Ni-based BMG’s indicating that these alloys are the easiest metallic glass formers based on Ni discovered to date. Secondly, certain binary alloys in the Cu-Zr and Cu-Hf systems were found to form bulk glasses with casting thickness as high as 2 mm. The discovery of these binary BMGs was very surprising since it had been widely considered that only multi-component (containing at least three elements) alloys could form bulk metallic glasses. These new binary BMGs provide interesting subjects for future theoretical studies such as molecular dynamics simulations since they possess both the simplicity of binary alloys and the good GFA of multi-component BMGs. In fact, these binary BMGs have led to the third but perhaps the most significant progress during this research, i.e., the discovery of a family of Cu-based BMGs in the Cu-Zr-Al-Y system which possess a c

Published
2005

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