11 results on '"Ruifang Chen"'
Search Results
2. On p-regular G-conjugacy class sizes.
- Author
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Xianhe Zhao, Ruifang Chen, and Xu Geng
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SOLVABLE groups , *CONJUGACY classes , *GROUP theory , *MATHEMATICAL inequalities , *INFINITE processes - Abstract
Let N be a normal subgroup of a p-solvable group G. The purpose of this paper is to investigate some properties of N under the condition that the two longest sizes of the non-central p-regular G-conjugacy classes of N are coprime. Some known results are generalized. [ABSTRACT FROM AUTHOR]
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- 2014
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3. Solid-Phase Parallel Synthesis of Phosphite Ligands.
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Bert H. G. Swennenhuis, Ruifang Chen, Piet W. N. M. van Leeuwen, Johannes G. de Vries, and Paul C. J. Kamer
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COORDINATION compounds , *ALCOHOL , *ALCOHOLS (Chemical class) , *ORGANIC compounds - Abstract
Various routes for the synthesis of polymer-bound phosphites and phosphoramidites have been investigated. In the presence of a suitable activator the supported phosphoramidites react cleanly with alcohols to give the corresponding monodentate phosphite ligands in solution. We have applied this novel solid-phase route in the parallel synthesis of several monodentate chiral and achiral phosphite ligands. [ABSTRACT FROM AUTHOR]
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- 2008
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4. Noncovalent Anchoring of Homogeneous Catalysts to Silica Supports with Well-Defined Binding Sites.
- Author
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Ruifang Chen, Bronger, Raymond P. J., Kamer, Paul C. J., van Leeuwen, Piet W. N. M., and Reek, Joost N. H.
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CATALYSTS , *SILICA , *BINDING sites , *LIGANDS (Chemistry) , *CHEMICAL inhibitors , *BIOCHEMISTRY - Abstract
The efficient reversible functionalization of silica with catalytic sites using noncovalent interactions is described. We prepared silica materials with well-defined binding sites that selectively bind guest molecules that are equipped with the complementary binding motif, with the interaction between the two components being based on either hydrogen bonds or metal-ligand interactions. Several phosphine ligands functionalized with glycine-urea groups, required for hydrogen bond formation to the complementary host on the silica, have been prepared. The resulting noncovalently immobilized complexes have been used as a ligand system in the Pd-catalyzed allylic substitution and Rh-catalyzed hydroformylation of 1 -octene. The supramolecular interaction between the transition-metal catalyst and the binding site located at the support is sufficiently strong to enable efficient catalyst recycling. In addition, the nature of the support facilitates the de- and refunctionalization of support, allowing the recycling of both homogeneous catalysts and the functionalized support. A rhodium catalyst based on a functionalized xantphos ligand was used in the hydroformylation of 1-octene in 11 consecutive reactions without showing catalyst deterioration or metal leaching. [ABSTRACT FROM AUTHOR]
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- 2004
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5. Note.
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Ruifang Chen, Tadeusz J. and Tatsumi, Kazuyuki
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LITHIUM , *METAL complexes , *COMPLEX compounds , *BUTADIENE , *COORDINATION compounds - Abstract
A new lithium complex with ( i Pr 2 C 6 H 3 ) 2 -dad ( N , N ′-bis ( i Pr 2 C 6 H 3 )-1,4-diaza-1,3-butadiene) has been synthesized. The crystal structure of {Li 3 [ i Pr 2 C 6 H 3 ) 2 -dad] 2 }{Li(THF) 4 }ċ0.5 Hexane [triclinic, $P\bar 1$ , a = 1.3154(2), b = 1.6720(2) nm, c = 1.8283(3) nm, α = 83.762(4), β = 70.152(2), γ = 68.267(2)°, V = 3.5127(8) nm 3 , D c = 1.05 g cm -3 , Z = 2] is described. [ABSTRACT FROM AUTHOR]
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- 2002
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6. Lipid accumulation product is a powerful tool to predict non-alcoholic fatty liver disease in Chinese adults.
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Haijiang Dai, Weijun Wang, Ruifang Chen, Zhiheng Chen, Yao Lu, and Hong Yuan
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FATTY liver , *AGE distribution , *CONFIDENCE intervals , *TRIGLYCERIDES , *MULTIPLE regression analysis , *STATISTICAL significance , *CROSS-sectional method , *SEVERITY of illness index , *RECEIVER operating characteristic curves , *WAIST circumference , *DIAGNOSIS ,RESEARCH evaluation - Abstract
Background: Non-alcoholic fatty liver disease (NAFLD), recognized as the liver manifestation of metabolic syndrome, is highly prevalent in the general population. Recent studies suggest that lipid accumulation product is significantly associated with metabolic abnormalities. The aim of this study was to assess the accuracy of lipid accumulation product (LAP) as an effective screening tool for diagnosing NAFLD in the general population. Methods: A total of 40,459 subjects aged ≥18 years were enrolled in this cross-sectional study. LAP was calculated as [waist circumference (cm) - 65] x triglyceride concentration (mmol//L) in men and [waist circumference (cm) - 58] x triglyceride concentration (mmol/L) in women. Multiple logistic regression and receiver operating characteristic (ROC) analyses were performed. Results: According to multiple logistic regression analyses, LAP was significantly associated with a higher prevalence and severity of NAFLD in both men and women. When assessed using ROC curve analyses, LAP exhibited high diagnostic accuracy for identifying NAFLD, and the areas under the curves (AUC) in men and women were 0.843 (95% CI 0.837, 0.849) and 0.887 (95% CI 0.882, 0.892), respectively. After further analyzed in different age groups, the diagnostic accuracy of LAP was found to be significantly better in younger age groups (aged 18-34 for men; aged 18-34 and 35-44 years for women) for both sexes. Conclusions: LAP is significantly associated with the presence and severity of NAFLD, and has a high diagnostic accuracy for identifying NAFLD in the general population. The diagnostic accuracy of LAP was especially high among younger age groups. [ABSTRACT FROM AUTHOR]
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- 2017
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7. The prognostic significance of anti-angiogenesis therapy in ovarian cancer: a meta-analysis.
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Jun Li, Shufen Li, Ruifang Chen, Hailin Yu, and Xin Lu
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NEOVASCULARIZATION inhibitors , *OVARIAN cancer treatment , *META-analysis , *PROGRESSION-free survival , *SENSITIVITY analysis , *BEVACIZUMAB , *THERAPEUTICS - Abstract
Objective: The prognostic value of anti-angiogenesis therapy in ovarian cancer patients is currently under debate. In this study, we assessed the effects of anti-angiogenesis therapy on the progression free survival (PFS) and overall survival (OS) of ovarian cancer patients. Materials and methods: PubMed was searched to identify relevant studies that evaluated the therapeutic value of anti-angiogenic agents in ovarian cancer (the final search was current to Dec. 13th 2014). Reviews of each study were conducted, and the data were extracted. The primary outcomes that were analysed were progression free survival (PFS) and overall survival (OS). The pooled hazard ratio (HR) and 95 % confidence intervals (CIs) were calculated using the random and fixed-effects models, and subgroup and sensitivity analyses were subsequently performed. Results: A total of 12 studies were included in the meta-analysis. The overall analysis revealed that the incorporation of anti-angiogenesis therapy was significantly associated with a longer PFS (HR, 0.66; 95 % CI, 0.58-0.75; P < 0.01) and a longer OS (HR, 0.89; 95 % CI, 0.82-0.97; P = 0.01) in the total population, and these findings were confirmed by one-way sensitivity analyses. Further subgroup analyses demonstrated that the administrations of each of the agents were associated with improved PFSs. The prognostic value of anti-angiogenesis therapy for the OS was significant in the trebananib subgroup (HR, 0.81; 95 % CI, 0.67-0.99; P = 0.04). The bevacizumab subgroup exhibited a similar trend that did not reach statistical significance (HR, 0.90; 95 % CI, 0.80-1.01; P = 0.08). Conclusions: The present meta-analysis indicated that anti-angiogenesis therapy in ovarian cancer patients was associated with a better clinical outcome. Further studies are warranted to identify the specific subgroup of patients who are most likely to benefit from anti-angiogenesis therapy. [ABSTRACT FROM AUTHOR]
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- 2015
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8. NRP1 regulates HMGB1 in vascular endothelial cells under high homocysteine condition.
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Ma, Yeshuo, Zhen Zhang, Runtai Chen, Rui Shi, Pingyu Zeng, Ruifang Chen, Yiping Leng, and Alex F. Chen
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NRP1 regulates HMGB1 in vascular endothelial cells under high homocysteine condition. Am J Physiol Heart Circ Physiol 316: H1039 –H1046, 2019. First published February 15, 2019; doi: 10.1152/ajpheart.00746.2018.—Endothelial inflammation plays an important role in hyperhomocysteinemia (HHcy)-associated vascular diseases. High mobility group box 1 (HMGB1) is a pro-inflammatory danger molecule produced by endothelial cells. However, whether HMGB1 is involved in vascular endothelial inflammation of HHcy is poorly understood. Neuropilin-1 (NRP1) mediates inflammatory response and activates mitogen-activated protein kinases (MAPKs) pathway that has been reported to be involved in regulation of HMGB1. The aim of this study was to determine the alteration of HMGB1 in HHcy, and the role of NRP1 in regulation of endothelial HMGB1 under high homocysteine (Hcy) condition. In the present study, we first observed that the plasma level of HMGB1 was elevated in HHcy patients and an experimental rat model, and increased HMGB1 was also observed in the thoracic aorta of an HHcy rat model. HMGB1 was induced by Hcy accompanied with upregulated NRP1 in vascular endothelial cells. Overexpression of NRP1 promoted expression and secretion of HMGB1 and endothelial inflammation; knockdown of NRP1 inhibited HMGB1 and endothelial inflammation induced by Hcy, which partially regulated through p38 MAPK pathway. Furthermore, NRP1 inhibitor ATWLPPR reduced plasma HMGB1 level and expression of HMGB1 in the thoracic aorta of HHcy rats. In conclusion, our data suggested that Hcy requires NRP1 to regulate expression and secretion of HMGB1. The present study provides the evidence for inhibition of NRP1 and HMGB1 to be the novel therapeutic targets of vascular endothelial inflammation in HHcy in the future. NEW & NOTEWORTHY This study shows for the first time to our knowledge that the plasma level of high mobility group box 1 (HMGB1) is elevated in hyperhomocysteinemia (HHcy) patients, and homocysteine promotes expression and secretion of HMGB1 partially regulated by neuropilin-1 in endothelial cells, which is involved in endothelial inflammation. Most importantly, these new findings will provide a potential therapeutic strategy for vascular endothelial inflammation in HHcy. [ABSTRACT FROM AUTHOR]
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- 2019
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9. Novel role of PKR in palmitate-induced Sirt1 inactivation and endothelial cell senescence.
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Yapei Li, Zhouyangfan Peng, Chunle Wang, Le Li, Yiping Leng, Ruifang Chen, Hong Yuan, Shenghua Zhou, Zhen Zhang, and Chen, Alex F.
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GALACTOSE , *GLUCOSIDASES , *ENDOTHELIAL cells , *PROTEIN kinases , *CELLULAR aging , *CARDIOVASCULAR diseases - Abstract
Endothelial cell senescence is regarded as a vital characteristic of cardiovascular diseases. Elevated palmitate (PA) is an independent risk factor of cardiovascular diseases, but its role in endothelial cell senescence is currently unknown. During the course of studying the prosenescent role of PA, we discovered a key role of dsRNA-dependent protein kinase [protein kinase R (PKR)] in endothelial senescence. Exposure of human umbilical vein endothelial cells (HUVECs) to PA-induced cell senescence is characterized by increased levels of senescence-associated β-galactose glucosidase activity, excessive production of reactive oxygen species production, impaired cellular proliferation, and G1 phase arrest. This phenomenon is associated with an increase of PKR autophosphorylation and decreased activity of sirtuin 1 (Sirt1), a pivotal antisenescent factor. PKR inactivation by PKR siRNA or its phosphorylation inhibitor 2-aminopurine significantly attenuated PAinduced HUVEC senescence by reversing Sirt1 activity and its downstream signaling. Moreover, to study the regulatory mechanism between PKR and Sirt1, we found that PKR promotes JNK activation to inhibit Sirt1 activity and that this effect could be reversed by the JNK inhibitor SP600125. These findings provide evidence that PKR mediates PA-induced HUVEC senescence by inhibiting Sirt1 signaling. Our study provides novel insights into the actions and mechanisms of PKR in endothelial senescence. [ABSTRACT FROM AUTHOR]
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- 2018
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10. What is the impact of PCSK9 rs505151 and rs11591147 polymorphisms on serum lipids level and cardiovascular risk: a metaanalysis.
- Author
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Chengfeng Qiu, Pingyu Zeng, Xiaohui Li, Zhen Zhang, Bingjie Pan, Peng, Zhou Y. F., Yapei Li, Yeshuo Ma, Yiping Leng, and Ruifang Chen
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GENETIC polymorphisms , *CARDIOVASCULAR diseases , *BLOOD lipids , *ODDS ratio , *ALLELES - Abstract
Background: PCSK9 rs505151 and rs11591147 polymorphisms are identified as gain- and loss-of-function mutations, respectively. The effects of these polymorphisms on serum lipid levels and cardiovascular risk remain to be elucidated. Methods: In this meta-analysis, we explored the association of PCSK9 rs505151 and rs11591147 polymorphisms with serum lipid levels and cardiovascular risk by calculating the standardized mean difference (SMD) and odds ratios (OR) with 95% confidence intervals (CI). Results: Pooled results analyzed under a dominant genetic model indicated that the PCSK9 rs505151 G allele was related to higher levels of triglycerides (SMD: 0.14, 95% CI: 0.02 to 0.26, P = 0.021, I2 = 0) and low-density lipoproteins cholesterol (LDL-C) (SMD: 0.17, 95% CI: 0.00 to 0.35, P = 0.046, I2 = 75.9%) and increased cardiovascular risk (OR: 1.50, 95% CI: 1.19 to 1.89, P = 0.0006, I2 = 48%). The rs11591147 T allele was significantly associated with lower levels of total cholesterol (TC) and LDL-C (TC, SMD: -0.45, 95% CI: -0.57 to -0.32, P = 0.000, I2 = 0; LDL-C, SMD: -0.44, 95% CI: -0.55 to -0.33, P = 0.000, I2 = 0) and decreased cardiovascular risk (OR: 0.77, 95% CI: 0.60 to 0.98, P = 0.031, I2 = 59.9) in Caucasians. Conclusions: This study indicates that the variant G allele of PCSK9 rs505151 confers increased triglyceride (TG) and LDL-C levels, as well as increased cardiovascular risk. Conversely, the variant T allele of rs11591147 protects carriers from cardiovascular disease susceptibility and lower TC and LDL-C levels in Caucasians. These findings provide useful information for researchers interested in the fields of PCSK9 genetics and cardiovascular risk prediction not only for designing future studies, but also for clinical and public health applications. [ABSTRACT FROM AUTHOR]
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- 2017
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11. Association between homocysteine and non-alcoholic fatty liver disease in Chinese adults: a cross-sectional study.
- Author
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Haijiang Dai, Weijun Wang, Xiaohong Tang, Ruifang Chen, Zhiheng Chen, Yao Lu, and Hong Yuan
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LIVER diseases , *FATTY liver , *CROSS-sectional method , *BODY mass index , *LOGISTIC regression analysis - Abstract
Background: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, and its prevalence is likely to rise even further. To help understand the pathogenesis and early prevention of progressive NAFLD, this large-scale study was designed to explore the potential association between homocysteine and the prevalence of NAFLD. Methods: A total of 7203 subjects aged 18 years or older were enrolled in this cross-sectional study. The association of homocysteine with the prevalence of NAFLD, in the total sample and stratified by subgroups, was examined using multiple logistic regression analyses. Results: Subjects in the higher quartiles of homocysteine had a higher prevalence of NAFLD. After multivariate adjustment, the odds ratio (OR) for NAFLD in the highest compared with the lowest quartile of homocysteine was 2.08 (95% confidence interval [CI] 1.61, 2.67). Moreover, in the subgroup analyses, we found an effect modification by gender, body mass index (BMI) and smoking status on the association between homocysteine and the prevalence of NAFLD (P for interaction: 0.001, 0.002 and <0.001, respectively). A stronger association was observed in female, obese and non-smoking adults than in male, normal weight and smoking subjects. Conclusion: Homocysteine was significantly associated with the prevalence of NAFLD, particularly in female, obese or non-smoking adults. [ABSTRACT FROM AUTHOR]
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- 2016
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