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Exact Tail Asymptotics for a Discrete-time Preemptive Priority Queue

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Acta Mathematicae Applicatae Sinica 2015年第1期31卷 43-58页

作者： Yang SONG Zai-ming LIU hong-shuai dai School of Mathematics and Statistics Central South University School of Statistics Shandong University of Finance and Economics

In this paper, we consider a discrete-time preemptive priority queue with different service com- pletion probabilities for two classes of customers, one with high-priority and the other with low-priority. This model corresponds to the classical preemptive priority queueing system with two classes of independent Poisson customers and a single exponential server. Due to the possibility of customers＇ arriving and departing at the same time in a discrete-time queue, the model considered in this paper is more complicated than the continuous- time model. In this model, we focus on the characterization of the exact tail asymptotics for the joint stationary distribution of the queue length of the two types of customers, for the two boundary distributions and for the two marginal distributions, respectively. By using generating functions and the kernel method, we get the exact tail asymptotic properties along the direction of the low-priority queue, as well as along the direction of the high-priority queue.

关键词： discrete-time queue stationary distribution kernel method exact tail asymptotics

Inhibiting SHP2 reduces glycolysis, promotes microglial M1 polarization, and alleviates secondary inflammation following spinal cord injury in a mouse model

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Neural Regeneration Research 2025年第3期20卷 858-872页

作者： Xintian Ding Chun Chen Heng Zhao Bin dai Lei Ye Tao Song shuai Huang Jia Wang Tao You Department of Orthopedics The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina Department of Orthopedics Provincial Hospital Affiliated to Anhui Medical UniversityHefeiAnhui ProvinceChina

Reducing the secondary inflammatory response, which is partly mediated by microglia, is a key focus in the treatment of spinal cord injury. Src homology 2-containing protein tyrosine phosphatase 2(SHP2), encoded by PTPN11, is widely expressed in the human body and plays a role in inflammation through various mechanisms. Therefore, SHP2 is considered a potential target for the treatment of inflammation-related diseases. However, its role in secondary inflammation after spinal cord injury remains unclear. In this study, SHP2 was found to be abundantly expressed in microglia at the site of spinal cord injury. Inhibition of SHP2 expression using siRNA and SHP2 inhibitors attenuated the microglial inflammatory response in an in vitro lipopolysaccharide-induced model of inflammation. Notably, after treatment with SHP2 inhibitors, mice with spinal cord injury exhibited significantly improved hind limb locomotor function and reduced residual urine volume in the bladder. Subsequent in vitro experiments showed that, in microglia stimulated with lipopolysaccharide, inhibiting SHP2 expression promoted M2 polarization and inhibited M1 polarization. Finally, a co-culture experiment was conducted to assess the effect of microglia treated with SHP2 inhibitors on neuronal cells. The results demonstrated that inflammatory factors produced by microglia promoted neuronal apoptosis, while inhibiting SHP2 expression mitigated these effects. Collectively, our findings suggest that SHP2 enhances secondary inflammation and neuronal damage subsequent to spinal cord injury by modulating microglial phenotype. Therefore, inhibiting SHP2 alleviates the inflammatory response in mice with spinal cord injury and promotes functional recovery postinjury.

关键词： apoptosis glycolysis inflammatory response microglia neurons polarization spinal cord injury Src homology 2-containing protein tyrosine phosphatase 2

Efect of Al Content on the Corrosion Behavior of Extruded Dilute Mg–Al–Ca–Mn Alloy

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Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 77-90页

作者： Bao‑Chang Liu shuai Zhang hong‑Wei Xiong Wen‑Hao dai Yin‑Long Ma College of Construction Engineering Jilin UniversityChangchun 130026China Key Laboratory of Drilling and Exploitation Technology in Complex Conditions of Ministry of Natural Resources Changchun 130026China

The microstructure,extrusion texture and corrosion behavior of extruded dilute Mg–Al–Ca–Mn alloy with diferent Al contents were *** corrosion rate of the alloy was more sensitive to the Fe *** 1.2 wt%Al showed the lowest corrosion rate,which was mainly attributed to the weakening of the cathode efect caused by the increase of the Al and the decrease of the Fe in the precipitated *** grains,stronger basal surface texture and higher corrosion potential deriving from the higher Al content of the matrix also further enhanced the corrosion resistance of the matrix.

关键词： Dilute magnesium alloys Corrosion behavior Al content Fe impurity Second phase

Climate and Soil Geochemistry Influence the Soil Organic Carbon Content in Drylands of the Songliao Plain,Northeast China

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1394-1403页

作者： LIU Kai dai Huimin SONG Yunhong LIANG shuai YANG Zhongfang School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Key Laboratory of Black Soil Evolution and Ecological Effect Ministry of Natural Resources/Liaoning ProvinceShenyang 110000China Shenyang Center of China Geological Survey Northeast Geological S&T Innovation Center of China Geological SurveyShenyang 110000China

The understanding of the spatial distribution of soil organic carbon(SOC)and its influencing factors is crucial for comprehending the global carbon ***,the impact of soil geochemical and climatic conditions on SOC remains limited,particularly in dryland farming *** this study,we aimed to enhance the understanding of the factors influencing the distribution of SOC in the drylands of the Songliao Plain,Northeast China.A dataset comprising 35,188 measured soil samples was used to map the SOC distribution in the *** linear regression(MLR)and random forest models(RFM)were employed to assess the importance of driving indicators for *** also carried out partial correlation and path analyses to further investigate the relationship between climate and *** SOC content in dryland soils of the Songliao Plain ranged from 0.05%to 11.63%,with a mean value of 1.47%±0.90%.There was a notable increasing trend in SOC content from the southwest to the northeast *** results of MLR and RFM revealed that temperature was the most critical factor,demonstrating a significant negative correlation with SOC ***,iron oxide was the most important soil geochemical indicator affecting SOC *** research further suggested that climate may exert an indirect influence on SOC concentrations through its effect on geochemical properties of *** insights highlight the importance of considering both the direct and indirect impact of climate in predicting the SOC under future climate change.

关键词： soil organic carbon climate change soil geochemistry Northeast China

Residual levels and health risk assessment of trace metals in Chinese resident diet

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Journal of Environmental Sciences 2024年第2期136卷 451-459页

作者： Yubing dai shuai Sun Rong Cao Haijun Zhang Jiping Chen Ningbo Geng CAS Key Laboratory of Separation Science for Analytical Chemistry Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Shenyang Pharmaceutical University Shenyang 110016China University of Chinese Academy of Sciences Beijing 100049China

Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions,atmospheric transport,and dry and wet deposition of *** present study focus on several trace metals that are rarely studied but have special toxicity,including tin(Sn),antimony(Sb),gold(Au),hafnium(Hf),palladium(Pd),platinum(Pt),ruthenium(Ru),tellurium(Te)and iridium(Ir).We investigated trace metals residues and distribution characteristics,and further evaluated the potential health risks from major daily food intakes in 33 cities in ***,Sb,Ir,Hf,and Au were frequently detected in food samples with the concentrations ranged from ND(not detected)to 24.78μg/kg ww(wet weight).Eggs exhibited the highest residual level of all detected metals(13.70±14.70μg/kg ww in sum),while the lowest concentrations were observed in vegetables(0.53±0.17μg/kg ww in sum).Sn accounting for more than 50%of the total trace metals concentration in both terrestrial and aquatic animal origin *** terrestrial plant origin foods,Sn and Ir were the most abundant *** and Au were the most abundant elements in egg *** addition,Sb and Ir showed a clear trophic dilution effect in terrestrial environments,while in aquatic ecosystems,Sn,Hf,and Au exhibited obvious trophic amplification *** calculated average estimated daily intake(EDI)via food consumption in five regions of China was 0.09μg/(kg·day),implying the health risk of aforementioned elements was acceptable.

关键词： Trace metals Accumulation characteristics Dietary exposure Estimated daily intake(EDI)

One-step and Continuous Fabrication of Coaxial Piezoelectric Fiber for Sensing Application

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Chinese Journal of Polymer Science 2023年第11期41卷 1778-1785,I0009页

作者： shuai-shuai Gui Bing-Xu Da Fei Peng Guo-Qiang Zheng Kun dai Chun-Tai Liu Chang-Yu Shen College of Materials Science and Engineering Key Laboratory of Material Processing and Mold(Ministry of Education)Henan Key Laboratory of Advanced Nylon Materials and ApplicationZhengzhou UniversityZhengzhou 450001China

Although there has been rapid advancement in piezoelectric sensors,challenges still remain in developing wearable piezoelectric sensors by a one-step,continuous and environmentally friendly *** this work,a 1D flexible coaxial piezoelectric fiber was directly fabricated by melt extrusion molding,whose core and sheath layer are respectively slender steel wire(i.e.,electrode)and PVDF(i.e.,piezoelectric layer).Moreover,such 1D flexible coaxial piezoelectric fiber possesses short response time and high sensitivity,which can be used as a selfpowered sensor for bending and vibration *** interestingly,such 1D flexible coaxial piezoelectric fiber(1D-PFs)can be further endowed with 3D helical ***,a wearable and washable motion monitoring system can be constructed via braiding such 3D helical piezoelectric fiber(3D-PF)into commercial *** work paves a new way for developing 1D and 3D piezoelectric fibers through a one-step,continuous and environmentally friendly method,showing potential applications in the field of sensing and wearable electronics.

关键词： Coaxial piezoelectric fiber Melt extrusion molding Bending and vibration sensing Motion monitoring system

Aberrant methylation of secreted protein acidic and rich in cysteine gene and its significance in gastric cancer

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World Journal of Gastroenterology 2019年第46期25卷 6713-6727页

作者： shuai Shao Nuo-Ming Zhou Dong-Qiu dai Department of Gastrointestinal Surgery the Fourth Affiliated Hospital of China Medical University

BACKGROUND Aberrant methylation in DNA regulatory regions could downregulate tumor suppressor genes without changing the ***,our knowledge of secreted protein acidic and rich in cysteine(SPARC)and its aberrant methylation in gastric cancer(GC)is still *** the present research,we performed fundamental research to clarify the precise function of methylation on SPARC and its significance in *** To investigate promoter methylation and the effects of the SPARC gene in GC cells and tissues and to evaluate its clinical *** Plasmids that overexpressed the SPARC gene were transfected into human GC BGC-823 cells;non-transfected cells were used as a control group(NC group).Quantitative real-time polymerase chain reaction and western blotting(WB)were then used to detect the expression of ***-specific polymerase chain reaction was executed to analyze the gene promoter methylation *** viability was measured by the cell counting kit-8 *** migration and invasion ability of cells were detected by scratch assays and transwell chamber assays,*** cycle events and apoptosis were observed with a flow *** The expression of SPARC mRNA in GC tissues and cells was significantly lower and showed differing degrees of hypermethylation,respectively,than that in normal adjacent tissues and control *** with 5-Aza-2’-deoxycytidine(5-Aza-Cdr)was able to restore the expression of SPARC and reverse promoter *** of the SPARC gene significantly inhibited proliferation,migration,and invasion of GC cells,while also causing cell cycle arrest and apoptosis;the NC group exhibited the opposite *** This study demonstrated that SPARC could function as a tumor suppressor and might be silenced by promoter ***,in GC cells,SPARC inhibited migration,invasion,and proliferation,caused cell cycle arrest at the G0/G1 phase,and promoted apoptos

关键词： Gastric cancer Secreted protein acidic and rich in cysteine Hypermethylation Clinicopathological features Tumor suppressor gene

Stability prediction of underground entry-type excavations based on particle swarm optimization and gradient boosting decision tree

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Underground Space 2023年第2期9卷 234-249页

作者： Jian Zhou shuai Huang Ming Tao Manoj Khandelwal Yong dai Mingsheng Zhao School of Resources and Safety Engineering Central South UniversityChangsha 410083China Institute of Innovation Science and SustainabilityFederation University AustraliaBallaratVIC 3350Australia Poly Xinlian Blasting Engineer Limited Corp GuiyangGuizhou 550002China Re

The stability of underground entry-type excavations will directly affect the working environment and the safety of *** critical span graphs and traditional statistics learning methods can not meet the requirements of high accuracy for stability assessment of entry-type ***,this study proposes a new prediction method based on machine learning to scientifically adjust the critical span ***,the particle swarm optimization(PSO)algorithm is used to optimize the core parameters of the gradient boosting decision tree(GBDT),abbreviated as ***,the classification performance of eight other classifiers including GDBT,k-nearest neighbors(KNN),two kinds of support vector machines(SVM),Gaussian naive Bayes(GNB),logistic regression(LR)and linear discriminant analysis(LDA)are also applied to compare with the proposed *** revealed that compared with the other eight models,the prediction performance of PSO-GBDT is undoubtedly the most reliable,and its classification accuracy is up to ***,this model has great potential to provide a more scientific and accurate choice for the stability prediction of underground *** addition,each classification model is used to predict the stability category of several grid points divided by the critical span graph,and the updated critical span graph of each model is discussed in combination with previous *** results show that the PSO-GBDT model has the advantages of being scientific,accurate and efficient in updating the critical span graph,and its output decision boundary has strict theoretical support,which can help mine operators make favorable economic decisions.

关键词： Stability Entry-type excavations Critical span graph Gradient boosting decision tree Particle swarm optimization

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