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173 results on '"Pan, Yuyang"'

5. Research on the Application and Optimization of Mathematical Models in Financial Market Risk Management

Author

Pan Yuyang

Subjects
Social Sciences
Abstract

This paper applied mathematical models to conduct an in-depth discussion and empirical analysis of financial market risk management. The daily rate of return data on the S&P 500 index, selected through data processing, included data cleaning, return calculation, data standardization, construction of the GARCH (1, 1) model, and a Copula model for predicting and analyzing risks. Empirical results indicate that the GARCH model has good simulation in capturing the market volatility change, while the Copula model holds clear advantages in modeling multivariate risk dependencies. In the modern economy, managing risks in the financial market plays a vital role. Optimization algorithms such as genetic algorithms and Bayesian optimization significantly improve the prediction accuracy and computational efficiency of the model. Compared with traditional historical simulation methods, these models perform better in risk prediction indicators (VaR and ES), proving their practicality and effectiveness in actual risk management. The research results verify that advanced mathematical models and optimization methods have important application value in financial market risk management, providing a scientific decision-making basis for investors and risk managers.

Published
2024
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9. Patterned discharges for material localized treatment in dielectric barrier discharge with modulated gas gap.

Author

Dong, Lifang, Zhang, Lijia, He, Yunan, Wei, Ting, Li, Yaohua, Li, Cheng, and Pan, Yuyang

Subjects
GLOW discharges, CHARGE coupled devices, X-ray photoelectron spectroscopy, ELECTRIC discharges, SCANNING electron microscopes
Abstract

Eight kinds of patterned discharges are obtained by changing the discharge parameters in a dielectric barrier discharge with modulated gas gaps, which are applicable to materials patterned treatment. A square superlattice pattern consisting of two dot sublattices and one ring sublattice is studied and used to treat a PI film. The formation mechanism is studied by intensified charge coupled device. The spatial distribution of the plasma parameters is measured using optical emission spectra. The gas temperatures as well as the electron densities of the three sublattices are significantly different from each other. The physical and chemical properties of the treated film are measured using a surface profiler, x-ray photoelectron spectroscopy, and scanning electron microscope. The transmissivity, wettability, and etching depth of the treated PI film demonstrate square superlattice pattern distribution, which verifies the predictions based on plasma parameter measurements. The dielectric barrier discharge device reported here is also applicable to materials' patterned growth. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Choice of Financing Mode for Serial Entrepreneurs in the Big Data Era

Author

Pan, Yuyang, Shi, Heyuzi, Niu, Guoying, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Abawajy, Jemal, editor, Xu, Zheng, editor, Atiquzzaman, Mohammed, editor, and Zhang, Xiaolu, editor

Published
2021
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15. Concentrated Solar Light Photoelectrochemical Water Splitting for Stable and High‐Yield Hydrogen Production.

Author

Dong, Wan Jae, Ye, Zhengwei, Tang, Songtao, Navid, Ishtiaque Ahmed, Xiao, Yixin, Zhang, Bingxing, Pan, Yuyang, and Mi, Zetian

Subjects
HYDROGEN production, PLATINUM nanoparticles, STANDARD hydrogen electrode, CHARGE carriers, SOLAR energy, GALLIUM nitride, SOLAR cells, DYE-sensitized solar cells
Abstract

Photoelectrochemical water splitting is a promising technique for converting solar energy into low‐cost and eco‐friendly H2 fuel. However, the production rate of H2 is limited by the insufficient number of photogenerated charge carriers in the conventional photoelectrodes under 1 sun (100 mW cm−2) light. Concentrated solar light irradiation can overcome the issue of low yield, but it leads to a new challenge of stability because the accelerated reaction alters the surface chemical composition of photoelectrodes. Here, it is demonstrated that loading Pt nanoparticles (NPs) on single crystalline GaN nanowires (NWs) grown on n+‐p Si photoelectrode operates efficiently and stably under concentrated solar light. Although a large number of Pt NPs detach during the initial reaction due to H2 gas bubbling, some Pt NPs which have an epitaxial relation with GaN NWs remain stably anchored. In addition, the stability of the photoelectrode further improves by redepositing Pt NPs on the reacted Pt/GaN surface, which results in maintaining onset potential >0.5 V versus reversible hydrogen electrode and photocurrent density >60 mA cm−2 for over 1500 h. The heterointerface between Pt cocatalysts and single crystalline GaN nanostructures shows great potential in designing an efficient and stable photoelectrode for high‐yield solar to H2 conversion. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Regulatory effect of Grifola frondosa extract rich in polysaccharides and organic acids on glycolipid metabolism and gut microbiota in rats

Author

Wei-Ling Guo, Zhong Ruting, Pan Yuyang, Xu-Cong Lv, Chao Zhao, Bin Liu, Feng Zeng, and Xuzhi Wan

Subjects
Male, 02 engineering and technology, Gut flora, Polysaccharide, Biochemistry, 03 medical and health sciences, Polysaccharides, Structural Biology, Animals, Hypoglycemic Agents, Organic Chemicals, Rats, Wistar, Cecum, Molecular Biology, Grifola frondosa, Hypolipidemic Agents, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, Bacteria, biology, Chemistry, Glucokinase, Acetyl-CoA carboxylase, General Medicine, Peroxisome, Lipid Metabolism, 021001 nanoscience & nanotechnology, biology.organism_classification, Sterol, Gastrointestinal Microbiome, Rats, Glucose, Liver, Models, Animal, Glycolipids, 0210 nano-technology, Acids, Grifola
Abstract

The present study investigated the composition of water extract of Grifola frondosa (GFWE) and its regulatory effects on glycolipid metabolism and gut microbiota in rats. Structural characteristics of GFWE were detected by high performance liquid chromatography and ultra-high-performance liquid chromatography with mass spectrometry. The hypoglycemic and hypolipidemic activities of GFWE were obtained by inhibition of weight gain, recovery of serum glucose and lipid, and reverse of liver tissue damage. GFWE has up-regulated the relative mRNA and protein expression levels of adenine monophosphate activated protein kinase-α, peroxisome proliferator-activated receptors-α, and glucokinase, while down-regulated sterol regulatory element-binding transcription factor-1c and acetyl CoA carboxylase. Moreover, GFWE increased the abundances of caecal bacteria Oscillibacter and Barnesiella, which showed a significant negative correlation with serum glucose and lipid parameters. And GFWE enhanced the levels of total bile acids and short-chain fatty acids in the cecum. These results indicated that GFWE could be provided as a potential candidate to regulate glycolipid metabolism and gut microbiota.

Published
2020

37. Coumarin-rich Grifola frondosa ethanol extract alleviate lipid metabolism disorders and modulates intestinal flora compositions of high-fat diet rats

Author

Ying Huang, Pan Yuyang, Chang'e Wang, Yilin Liu, Jia-Xin Xu, Jie Pang, Xiaodong Ge, Heping Zheng, Feng Zeng, and Bin Liu

Subjects
chemistry.chemical_classification, Nutrition and Dietetics, Lipid Metabolism Disorder, biology, Glucokinase, Cholesterol, Grifola frondosa, Nutrition. Foods and food supply, Glutathione peroxidase, Medicine (miscellaneous), Fatty acid, Aspartate transaminase, Superoxide dismutase, chemistry.chemical_compound, Glucose and lipid metabolism, Intestinal flora, chemistry, Biochemistry, Coumarins, biology.protein, TX341-641, Food Science
Abstract

This study investigated Grifola frondosa active substances extracted from low-concentration (55%) ethanol (GF55) and their role in regulating glucose and lipid metabolism disorders (GLMDs). The main components of GF55 were identified as fatty acids and coumarins by UPLC-Q-TOF-MS/MS After the intervention of GF55, the serum and liver lipid level, aspartate transaminase, alanine aminotransferase, free fatty acid, total superoxide dismutase, glutathione peroxidase, liver histopathological and key genes, short-chain fatty acids and intestinal flora changed. Compared with HFD, GF55 treatment up-regulated the expressions of protein kinase B, glucokinase, adenine monophosphate-activated protein kinase-α and cholesterol 7-α hydroxylase, down-regulated the expressions of stearoyl-CoA desaturase 1, acetyl-CoA carboxylase and sterol regulatory element-binding transcription factor-1c at the mRNA and protein levels (P

Published
2021

38. Effect of Grifola frondosa 95% ethanol extract on lipid metabolism and gut microbiota composition in high-fat diet-fed rats

Author

Feng Zeng, Bin Liu, Tian-Tian Li, Rui-Bo Jia, Zi-Rui Huang, Pan Yuyang, Wei-Ling Guo, Jiachao Zhang, and Xu-Cong Lv

Subjects
Male, 0301 basic medicine, Hyperlipidemias, Gut flora, Diet, High-Fat, Flavones, Excretion, Caecum, 03 medical and health sciences, Cecum, chemistry.chemical_compound, medicine, Animals, Humans, Food science, Rats, Wistar, Triglycerides, Grifola frondosa, chemistry.chemical_classification, Bacteria, Triglyceride, biology, Lipid metabolism, General Medicine, Lipid Metabolism, biology.organism_classification, Gastrointestinal Microbiome, Rats, Cholesterol, 030104 developmental biology, medicine.anatomical_structure, Liver, chemistry, lipids (amino acids, peptides, and proteins), Drugs, Chinese Herbal, Grifola, Food Science
Abstract

This study aimed to investigate the effects of 95% ethanol extract of G. frondosa (GF95) on lipid metabolism and gut microbiota composition in high-fat diet (HFD) fed rats. UPLC/Q-TOF MS indicated that GF95 was enriched with flavones, fatty acids and so on. Meanwhile, we found that body weight, serum lipid or liver index (total cholesterol, triglyceride, and low density lipoprotein cholesterol) levels were significantly decreased in GF95-treated HFD-fed rats. Furthermore, GF95 treatment regulated mRNA expression levels involved in lipid metabolism. GF95 consumption significantly enhanced the excretion of bile acids in the cecum. Besides, in this study, a higher abundance of Butyricimonas genus was revealed in the GF95 group, which is highly related to the highest production of short-chain fatty acids in the caecum contents among the experimental groups. Interestingly, results from network analysis showed that Butyricimonas were negatively correlated with serum and liver lipid profiles.

Published
2018

49. Efficient photoelectrochemical conversion of CO2to syngas by photocathode engineering

Author

Chu, Sheng, Ou, Pengfei, Rashid, Roksana Tonny, Pan, Yuyang, Liang, Daolun, Zhang, Huiyan, and Song, Jun

Abstract

The synthesis of renewable chemical fuels from CO2and H2O via photoelectrochemical (PEC) route reprensents a promising room-temperature approach for transforming greenhouse gas into value-added chemicals (e.g., syngas), but to date it has been hampered by the lack of efficient photocathode for CO2reduction. Herein, we report efficient PEC CO2reduction into syngas by photocathode engineering. The photocathode is consisting of a planar p-n Si junction for strong light harvesting, GaN nanowires for efficient electron extraction and transfer, and Au/TiO2for rapid electrocatalytic syngas production. The photocathode yields a record-high solar energy conversion efficiency of 2.3%. Furthermore, desirable syngas compositions with CO/H2ratios such as 1:2 and 1:1 can be produced by simply varying the size of Au nanoparticle. Theoretical calculations reveal that the active sites for CO and H2generation are the facet and undercoordinated sites of Au particles, respectively.

Published
2022
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50. Hypoglycemic and hypolipidemic activities of Grifola frondosa polysaccharides and their relationships with the modulation of intestinal microflora in diabetic mice induced by high-fat diet and streptozotocin

Author

Li Ni, Pan Yuyang, Yan-Yan Zhang, Min Qian, Fei-Fei Shi, Bin Liu, Gong-Liang Liu, Jia-Li Hong, Xu-Cong Lv, Jia-Cong Deng, Pingfan Rao, Zhang Wen, Wei-Ling Guo, Jia-Xin Xu, Weidong Bai, and Peng-Jie Luo

Subjects
Male, medicine.medical_specialty, 02 engineering and technology, Gut flora, Cholesterol 7 alpha-hydroxylase, Diet, High-Fat, Biochemistry, Diabetes Mellitus, Experimental, 03 medical and health sciences, chemistry.chemical_compound, Mice, Structural Biology, Internal medicine, Hyperlipidemia, medicine, Animals, Hypoglycemic Agents, Molecular Biology, Cecum, Grifola frondosa, 030304 developmental biology, Hypolipidemic Agents, 0303 health sciences, Triglyceride, biology, Cholesterol, Body Weight, Lipid metabolism, Fungal Polysaccharides, General Medicine, 021001 nanoscience & nanotechnology, medicine.disease, Streptozotocin, biology.organism_classification, Fatty Acids, Volatile, Lipid Metabolism, Gastrointestinal Microbiome, Endocrinology, Glucose, chemistry, Liver, 0210 nano-technology, medicine.drug, Grifola
Abstract

This study aimed to investigate the hypoglycemic and hypolipidemic activities of polysaccharides from Grifola frondosa (GFP) in diabetic mice induced by high-fat diet (HFD) and streptozotocin (STZ). Results showed that oral administration of GFP markedly reduced the serum levels of fasting blood glucose (FBG), oral glucose tolerance (OGT), cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C), and significantly decreased the hepatic levels of TC, TG and free fatty acids (FFA). Meanwhile, high-dose of GFP supplementation (900 mg/kg day) also showed powerful effects on moderating the composition of intestinal microflora in diabetic mice, especially altering the functionally relevant intestinal microbial phylotypes. Spearman’s correlation network analysis revealed that key microbial phylotypes responding to GFP intervention were strongly correlated with the glucose and lipid metabolic disorders associated parameters. Moreover, GFP treatment regulated mRNA expression levels of the genes responsible for hepatic glucose and lipid metabolism. It is noteworthy that GFP treatment markedly increased mRNA expression of cholesterol 7α-hydroxylase (CYP7A1) and bile salt export pump (BSEP), suggesting an enhancement of bile acids (BAs) synthesis and excretion in liver. These findings demonstrated that GFP could prevent hyperglycemia and hyperlipidemia in diabetic mice by altering gut microbiota and regulating hepatic glycolipid metabolism related genes, and therefore could be used as potential functional food ingredients for the prevention or treatment of hyperglycemia and hyperlipidemia.

Published
2019

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