Experimental Study on Dispersion of Unconfined Aquifer in a Site of Jilin City

Dispersion parameter is an important parameter for the establishment of groundwater solute transport model.The dispersion test uses sodium chloride as a tracer,which was conducted in a site in Jilin City.The standard curve comparison method was used to solve the dispersion parameters of the aquifer under the natural flow field.The test results show that under the natural flow field,the longitudinal dispersion of unconfined aquifer in Jilin City is 0.400m,and the transverse dispersion is 1.933×10-5~6.557×10-3m;while the longitudinal dispersion coefficient is 0.246m2/d,the transverse dispersion coefficient is 1.191×10-5~4.039×10-3m2/d.The above results can provide an important parameter basis for the establishment of groundwater solute transport model,the accurate prediction of temporal and spatial variation of pollutant concentration in groundwater and the formulation of groundwater pollution prevention and control scheme.

中老年轻度认知障碍人群血脂及胰岛素抵抗相关指标与认知评分的相关性

目的分析中老年轻度认知障碍(MCI)人群血脂及胰岛素抵抗相关指标与认知评分的相关性。方法本研究为横断面研究,连续选取2021年1月1日—7月31日在首都医科大学附属北京天坛医院健康管理中心进行体检且蒙特利尔认知功能量表(MoCA)评分≥18分的262例中老年人群为研究对象,根据认知功能和MoCA评分分为MCI组(143例)和认知正常组(119例)。收集两组基本资料、空腹血糖、甘油三酯(TG)、总胆固醇、载脂蛋白E(ApoE)基因型等临床指标,采用假设检验比较两组基本资料、血脂及胰岛素抵抗相关指标差异,采用Spearman相关性分析评估两组血脂及胰岛素抵抗相关指标与MoCA评分的相关性。结果MCI组年龄及高血压、冠心病、糖尿病患者比例均显著高于认知正常组[(54.83±8.29)比(50.76±6.34)岁、37.76%比31.93%、4.20%比0.84%、16.08%比8.40%](均P<0.05)。MCI组血清TG升高(r=-0.50,95%CI:-0.88~-0.12)、TG葡萄糖乘积指数(TyG)升高(r=-0.75,95%CI:-1.29~-0.20)、TG高密度脂蛋白胆固醇比值(TG/HDL-C)升高(r=-0.52,95%CI:-0.91~-0.13)均与MoCA评分呈负相关(均P<0.05);校正年龄、性别后,TG升高(r=-0.39,95%CI:-0.75~-0.31)、TG/HDL-C升高(r=-0.43,95%CI:-0.80~-0.05)仍与MoCA评分呈负相关(均P<0.05)。认知正常组各指标与MoCA评分的相关性差异均无统计学意义(均P>0.05)。MCI组携带ApoEε4基因型人群TG升高与MoCA评分呈负相关(r=-0.70,95%CI:-1.23~0.16,P=0.017);携带ApoEε2、ApoEε3基因型人群TG与MoCA评分的相关性差异均无统计学意义(均P>0.05)。结论中老年MCI人群血脂及胰岛素抵抗相关指标升高与认知评分呈负相关,这在携带ApoEε4基因型人群中更为明显。

Tea picking point detection and location based on Mask-RCNN

The accurate identification,detection,and segmentation of tea buds and leaves are important factors for realizing intelligent tea picking.A tea picking point location method based on the region-based convolutional neural network(R-CNN)Mask-RCNN is proposed,and a tea bud and leaf and picking point recognition model is established.First,tea buds and leaf pictures are collected in a complex environment,the Resnet50 residual network and a feature pyramid network(FPN)are used to extract bud and leaf features,and preliminary classification and preselection box regression training-performed on the feature maps through a regional proposal network(RPN).Second,the regional feature aggregation method(RoIAlign)is used to eliminate the quantization error,and the feature map of the preselected region of interest(ROI)is converted into a fixed-size feature map.The output module of the model realizes the functions of classification,regression and segmentation.Finally,through the output mask image and the positioning algorithm the positioning of the picking points of tea buds and leaves is determined.One hundred tea tree bud and leaf pictures in a complex environment are selected for testing.The experimental results show that the average detection accuracy rate reaches 93.95%and that the recall rate reaches 92.48%.The tea picking location method presented in this paper is more versatile and robust in complex environments.

Joint Effects of Heat Stress and PM_(2.5) Exposure on Glucose Metabolism and Hepatic Insulin Signaling

Background:Heatwave events occur more frequently,accompanied by a significant increase in the ambient concentration of fine particulate matter(PM 2.5).Epidemiological and experimental studies have suggested that heat stress or PM 2.5 exposure would impair glucose homeostasis and insulin sensitivity.Objective:To explore the joint effects of heat stress and PM 2.5 exposure on glucose metabolism and hepatic insulin pathway.Methods:C57BL/6 mice were randomly divided into filtered air(FA)group,fine particulate matter(PM)group,filtered air combined with heat stress(FH)group,and PM combined with heat stress(PH)group.Mice were exposed to PM for a total of 6 weeks,and heat stress combined with PM exposure was applied at the 5th and 6th weeks via a whole-body exposure system.Systemic glucose homeostasis,insulin sensitivity,and circulating inflammatory cytokines were examined.HSP72 expression and insulin signaling in the liver were measured.Results:Glucose tolerance and insulin sensitivity were impaired in response to heat stress,accompanied by less-ened hepatic GLUT2 expression and inhibited insulin signaling pathway.No synergistic effects of heat stress and PM 2.5 exposure on glucose homeostasis were observed,while heat-upregulated HSP72 expression was attenuated with accumulated TNF𝛼induced by further PM 2.5 exposure.Conclusion:Heat stress combined with PM 2.5 exposure induced TNF𝛼,which could inhibit heat-elevated hepatic HSP72 expression.Elevated circulating TNF𝛼impaired hepatic insulin signaling and GLUT2 expression.Then,glucose homeostasis was perturbed,and insulin action was impaired.

Symptom clustering in chronic gastritis based on spectral clustering

OBJECTIVE: Apply spectral clustering to analyze the patterns of symptoms in patients with chronic gastritis(CG).METHODS: Based on 919 CG subjects, we applied mutual information feature selection to choose the positively correlated symptoms with each pattern.Then, we used the Shi and Malik spectral clustering algorithm to select the top 20 correlated symptoms.RESULTS: We ascertained the results of six patterns.There were three categories for the pattern of accumulation of damp heat in the spleen-stomach(0.00332). There were six categories for the pattern of dampness obstructing the spleen-stomach(0.02466). There were two categories for the pattern of spleen-stomach Qi deficiency(0.013 89).There were three categories for the pattern of spleen-stomach deficiency cold(0.009 15). There were five categories for the pattern of liver-Qistagnation(0.01910).There were four categories for the pattern of stagnant heat in the liver-stomach(0.00585).CONCLUSION: Most of the spectral clustering results of the symptoms of CG patterns were in accordance with clinical experience and Traditional Chinese Medicine theory. Most categories suggested the nature and/or location of the disease.

Study on the growth of platinum nanowires as cathode catalysts in proton exchange membrane fuel cells

The platinum nanowires have been verified to be a promising catalyst to promote the performance of proton exchange membrane fuel cells.In this paper,accurately controlled growth of nanowires in a carbon matrix is achieved for reducing Pt loading.The effects of formic acid concentration and reaction temperature on the morphology and size of the Pt nanowires,as well as their electrochemical performances in a single cell,are investigated.The results showed that the increase in the formic acid concentration results in a volcano trend with the length of Pt nanowires.With increasing reduction temperature,the diameter of Pt nanowires increases while Pt particles evolve from one-dimensional to zero-dimensional up to 40°C.A mechanism of the Pt nanowires growth is proposed.The optimized Pt nanowires electrode exhibits a power density(based on electrochemical active surface area)79%higher than conventional Pt/C one.The control strategy obtained contributes to the design and control of novel nanostructures in nano-synthesis and catalyst applications.

Cathode Design for Proton Exchange Membrane Fuel Cells in Automotive Applications

An advanced cathode design can improve the power performance and durability of proton exchange membrane fuel cells(PEMFCs),thus reducing the stack cost of fuel cell vehicles(FCVs).Recent studies on highly active Pt alloy catalysts,short-side-chain polyfluorinated sulfonic acid(PFSA)ionomer and 3D-ordered electrodes have imparted PEMFCs with boosted power density.To achieve the compacted stack target of 6 kW/L or above for the wide commercialization of FCVs,developing available cathodes for high-power-density operation is critical for the PEMFC.However,current developments still remain extremely challenging with respect to highly active and stable catalysts in practical operation,controlled distribution of ionomer on the catalyst surface for reducing catalyst poisoning and oxygen penetration losses and 3D(three-dimensional)-ordered catalyst layers with low Knudsen diffusion losses of oxygen molecular.This review paper focuses on impacts of the cathode development on automotive fuel cell systems and concludes design directions to provide the greatest benefit.