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Optimal Timing of Business Conversion for Solvency Improvement

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 744-757页

作者： Peng LI Ming zhou School of Finance Nanjing University of Finance and EconomicsNanjing 210023China Center for Applied Statistics and School of Statistics Renmin University of ChinaBeijing 100872China

In this paper,we study the optimal timing to convert the risk of business for an insurance company in order to improve its *** cash flow of company evolves according to a jump-diffusion *** conversion option offers the company an opportunity to transfer the jump risk business *** exchange for this option,the company needs to pay both fixed and proportional transaction *** proportional cost can also be seen as the profit loading of the jump risk *** formulated this problem as an optimal stopping *** solving this stopping problem,we find that the optimal timing of business conversion mainly depends on the profit loading of the jump risk business.A larger profit loading would make the conversion option *** fixed cost,however,only delays the optimal timing of business *** the end,numerical results are provided to illustrate the impacts of transaction costs and environmental parameters to the optimal strategies.

关键词： optimal stopping jump-diffusion process conversion option

Small Cycles Property of Some Cremer Rational Maps and Polynomials

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 123-136页

作者： Rong FU Ji zhou Faculty of Science Yibin UniversityYibin 644000SichuanChina Department of Mathematical Sciences Sichuan Normal UniversityChengdu 610066China

This paper concerns the linearization problem on rational maps of degree d≥2 and polynomials of degree d>2 from the perspective of *** authors introduce a set l_(∞) of irrational numbers and show that if α∈l_(∞),then any rational map is not linearizable and has infinitely many cycles in every neighborhood of the fixed point with multiplier λ=e^(2πiα),Adding more constraints to cubic polynomials,they discuss the above problems by polynomial-like *** the family of polynomials,with the help of Yoccoz's method,they obtain its maximum dimension of the set in which the polynomials are non-linearizable.

关键词： Irrationally indifferent fixed point Linearization problem Small cycles property

Southern Hemisphere Volcanism Triggered Multi-year La Niñas during the Last Millennium

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Advances in Atmospheric Sciences 2024年第4期41卷 587-592页

作者： Shangrong zhou Fei LIU School of Atmospheric Sciences Sun Yat-Sen University Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Educationand Southern Marine Science and Engineering Guangdong LaboratoryZhuhai 519082China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science and TechnologyNanjing 210044China

To explain the recent three-year La Niña event from 2020 to 2022,which has caused catastrophic weather events worldwide,Fasullo et al.(2023)demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Niñ***,we present compelling evidence from paleo-proxies,utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere(SH),to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Niña *** research highlights the importance of focusing on the Southern Ocean,as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.

关键词： volcanic eruptions multi-year La Niñas Australian wildfire southern ocean cooling

The Influence of Significant Public Health Events on Offline Consumption and Its Pathways

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Journal of Systems Science and Systems Engineering 2024年第5期33卷 627-648页

作者： Baile Lu Kewei zhou Shuai Hao La Ta Hongyan Dai Weihua zhou College of Systems Engineering National University of Defense TechnologyChangsha 410073China Business School Central University of Finance and EconomicsBeijing 100081China Department of Marketing and Operations Management College of BusinessSouthern University of Science and TechnologyShenzhen 518055China School of Management Zhejiang UniversityHangzhou 310058China

In the face of a significant public health event,consumers may either increase their panic buying or decrease their willingness to make *** study focuses on the impact of a significant public health event on offline store sales and consumer consumption,utilizing data from chain convenience stores in Hefei and Wuhu during early 2019 and early 2020 in *** a difference-in-differences model,the study investigates the effect of the significant public health event outbreak on weekly store sales,order numbers,and consumer consumption in terms of product quantities,transaction amount,average amount per order,and transaction *** from prior literature that finds hoarding behavior of consumers online,the findings of this paper indicate a significant reduction in stores’offline weekly sales and order numbers,as well as consumers’offline weekly consumption across the four dimensions,as a result of the significant public health event ***,employing a mediation model,the study explores the pathway of population mobility through which the significant public health event adversely affects offline ***,subset analysis is conducted for stores located in different areas and consumers with varying characteristics,revealing that the aforementioned conclusions predominantly apply to stores situated in office areas and residential areas,as well as consumers with either no apparent preference for different product categories or a noticeable preference for food.

关键词： Significant public health event offline consumption population mobility mediating effect

Perturbation of autophagy pathways in murine alveolar macrophage by 2D TMDCs is chalcogen-dependent

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Journal of Environmental Sciences 2024年第1期135卷 97-107页

作者： Xiaofei zhou Weitao Jin Rui Zhang Xuan Mao Jianbo Jia Hongyu zhou College of Science&Technology Hebei Agricultural UniversityHuanghua 061100China Institute of Environmental Research at Greater Bay Area Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006China

Increasing risks of incidental and occupational exposures to two-dimensional transition metal dichalcogenides(2D TMDCs)due to their broad application in various areas raised their public health *** the composition-dependent cytotoxicity of 2D TMDCs has been well-recognized,how the outer chalcogenide atoms and inner transition metal atoms differentially contribute to their perturbation on cell homeostasis at non-lethal doses remains to be *** the present work,we compared the autophagy induction and related mechanisms in response to WS_(2),NbS_(2),WSe_(2)and Nb Se_(2)nanosheets exposures in MH-S murine alveolar *** these 2D TMDCs had comparable physicochemical properties,overall cytotoxicity and capability in triggering autophagy in MH-S cells,but showed outer chalcogen-dependent subcellular localization and activation of autophagy ***,WS_(2)and NbS_(2)nanosheets adhered on the cell surface and internalized in the lysosomes,and triggered m TOR-dependent activation of ***,WSe_(2)and Nb Se_(2)nanosheets had extensive distribution in cytoplasm of MH-S cells and induced autophagy in an m TOR-independent ***,the 2D TMDCs-induced perturbation on autophagy aggravated the cytotoxicity of respirable benzo[a]*** findings provide a deeper insight into the potential health risk of environmental 2D TMDCs from the perspective of homeostasis perturbation.

关键词： Chalcogen group Autophagy pathway Cell function Endosomal escape Inhalation toxicity

黄酒多糖对炎症性肠病及便秘作用机制的研究进展

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食品与发酵工业 2021年第9期47卷 275-283页

作者：史瑛冯欣静周志磊姬中伟徐岳正毛健粮食发酵工艺与技术国家工程实验室(江南大学) 江苏无锡214122 江南大学食品学院江苏无锡214122 国家黄酒工程技术研究中心浙江绍兴312000

独特的酿造体系及低温长时的酿造工艺赋予了黄酒丰富的生物活性物质,多糖作为黄酒中主要的生物活性成分,含量丰富,种类独特,具有平衡肠道菌群、改善肠内环境等功效。由于黄酒多糖组分复杂,难以提取专一成分进行靶向研究,目前针对黄酒多... 详细信息

独特的酿造体系及低温长时的酿造工艺赋予了黄酒丰富的生物活性物质,多糖作为黄酒中主要的生物活性成分,含量丰富,种类独特,具有平衡肠道菌群、改善肠内环境等功效。由于黄酒多糖组分复杂,难以提取专一成分进行靶向研究,目前针对黄酒多糖的功能研究主要集中于调节肠道菌群,对其他肠道疾病的影响及其作用机制尚未明确。该文论述了黄酒多糖的来源、提取工艺、结构分析,并阐述了黄酒多糖等膳食多糖对机体肠道屏障的维护、便秘症状的缓解及炎症性肠病的治疗机理,为黄酒多糖的后续功能研究提供了理论基础与新的思路。

关键词：黄酒多糖肠道菌群肠道屏障便秘炎症性肠病

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黄酒低聚糖的分离纯化与体外菌群增殖评价

食品与发酵工业 2022年第18期48卷 34-41页

作者：冯欣静周志磊姬中伟杨懿徐岳正毛健粮食发酵与食品生物制造国家工程研究中心江苏无锡214122 江南大学食品学院江苏无锡214122 江南大学(绍兴)产业技术研究院浙江绍兴312000 国家黄酒工程技术研究中心浙江绍兴312000

多菌种共酵工艺在低温长时的发酵条件下可赋予黄酒丰富的低聚糖。该研究以半干型黄酒为原料,对黄酒中低聚糖进行分离纯化及结构表征。利用75%乙醇沉淀黄酒中低聚糖,并经Sevage法除蛋白、300 Da与3000 Da膜分离、冷冻干燥等途径获得粗黄... 详细信息

多菌种共酵工艺在低温长时的发酵条件下可赋予黄酒丰富的低聚糖。该研究以半干型黄酒为原料,对黄酒中低聚糖进行分离纯化及结构表征。利用75%乙醇沉淀黄酒中低聚糖,并经Sevage法除蛋白、300 Da与3000 Da膜分离、冷冻干燥等途径获得粗黄酒低聚糖,其提取率达31.80%。粗黄酒低聚糖经琼脂糖凝胶柱DEAE Sepharose Fast Flow与葡聚糖凝胶柱Sephadex G15纯化可获得纯度为84.21%的黄酒低聚糖组分a(Huangjiu oligosaccharide-a,HJO-a)。通过建立小鼠粪便菌群体外发酵模型,探究HJO-a对肠道菌群的益生作用。结果表明,黄酒低聚糖被肠道菌群酵解后可提高发酵液中乙酸、丙酸、丁酸与异丁酸的含量,降低发酵液pH。此外,黄酒低聚糖显著提高了发酵液中肠道双歧杆菌、乳杆菌与拟杆菌的丰度(P<0.05),并显著抑制了发酵液中大肠杆菌的增殖(P<0.05)。上述结果揭示了黄酒低聚糖可发挥潜在的益生元作用。该研究为黄酒低聚糖的提取纯化及功能活性分析提供一定的理论依据。

关键词：黄酒低聚糖膜分离肠道菌群体外增殖

Natural polysaccharide-based smart CXCR4-targeted nano-system for magnified liver fibrosis therapy

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Chinese Chemical Letters 2024年第2期35卷 341-346页

作者： Liqiong Sun Xinping Luo Chenxi zhou Zhanwei zhou Minjie Sun College of Horticulture Nanjing Agricultural UniversityNanjing 210095China NMPA Key Laboratory for Research and Evaluation of Pharmaceutical Preparations and Excipients State Key Laboratory of Natural MedicinesDepartment of PharmaceuticsChina Pharmaceutical UniversityNanjing 210009China

Activated hepatic stellate cells(aHSCs),the main source of extracellular matrix deposition,are key targets in liver ***,no effective drug specific to aHSCs has been clinically applied due to poor drug delivery ***,we designed a CXC chemokine receptor 4(CXCR4)-targeted reactive oxygen species(ROS)-responsive platform AMD-Dex-ROS-responsive-sorafenib(ARS)based on natural polysaccharide and thioctic acid frame,which can deliver anti-fibrosis drug represented by sorafenib specifically to aHSCs on account of CXCR4 over-expression on aHSCs,and smartly disassemble via ROS-responsive thioketal rupture relying on high intracellular ROS in HSCs,realized on-demand drug release and effective liver fibrosis ***,in this platform,the CXCR4 antagonist AMD3100 not only enhanced aHSCs targeting efficiency of sorafenib but also effectively magnified the aHSCs elimination of sorafenib by blocking stroma cell derived factor-1(SDF-1)/CXCR4-induced aHSCs protection,resulting in synergistic anti-fibrosis *** platform provided a new approach for drug delivery system design and liver fibrosis treatment.

关键词： Nanoparticle CXCR4 antagonism ROS-responsive Hepatic stellate cells Liver fibrosis

Intrinsic correlation between the generalized phase equilibrium condition and mechanical behaviors in hydrate-bearing sediments

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2822-2832页

作者： Jiazuo zhou Changfu Wei Rongtao Yan Yuan zhou Yi Dong Hubei Key Laboratory of Marine Geological Resources College of Marine Science and TechnologyChina University of GeosciencesWuhanChina State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanChina Guangxi Key Laboratory of New Energy and Building Energy Saving College of Civil Engineering and ArchitectureGuilin University of TechnologyGuilinChina

The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate *** heating closed systems,the temperature-pressure path of hydrate-bearing sediment deviates from that of pure bulk hydrate,reflecting the porous media effect in phase equilibrium.A generalized phase equilibrium equation was established for hydrate-bearing sediments,which indicates that both capillary and osmotic pressures cause the phase equilibrium curve to shift leftward on the temperature-pressure *** contrast to bulk hydrate,hydrate-bearing sediment always contains a certain amount of unhydrated water,which keeps phase equilibrium with the hydrate within the hydrate stability *** changes in temperature and pressure,a portion of pore hydrate and unhydrated water may transform into each other,affecting the shear strength of hydrate-bearing sediment.A shear strength model is proposed to consider not only hydrate saturation but also the change in temperature and pressure of hydrate-bearing *** model is validated by experimental data with various hydrate saturation,temperature and pressure *** deformation induced by partial dissociation was studied through depressurization tests under constant effective *** reduction in gas pressure within the hydrate stability field indeed caused sediment *** dissociation-induced deformation can be reasonably estimated as the difference in volume between hydrate-bearing and hydrate-free sediments from the compression curves.

关键词： Hydrate-bearing sediment Generalized phase equilibrium Unhydrated water Partial dissociation Mechanical behavior