Management and prevention of mastitis:A multifactorial approach with a focus on milking,bedding and data-management

Mastitis is a complex, multifactorial disease. Pathogens, cows and farmers （via management） all play a role. It is costly and annoying for the farmer and threatens the image of the entire dairy industry. Prevention and control of mastitis is based on multiple principles that have been known for a long time. To implement them successfully, they should be put forward by a motivated and motivating advisor that transfers the existing knowledge to the farmer. When the changes are data-driven, applied by an encouraged farmer through a farm-specific implementation, prevention and control of mastitis will be successful and result in happy cows, happy farmers, happy advisors, happy consumers, and a happy industry. Nationwide projects focussing on communication and transfer of existing knowledge in prevention and control are very helpful in reaching high numbers of farmers and advisors and harmonizing the message brought by different parties. This paper gives an overview of multifactorial approach of mastitis management and prevention with a focus on milking, bedding and data-analysis.

数据流上的一种适应性调度策略MultiFactor

本文针对数据流系统中的查询处理机制进行了深入的研究,从内存使用量、系统的响应时间和查询的实时性三个方面进行综合考虑,提出了一种基于多因素的动态调度策略MultiFactor.该策略根据单位时间查询内各操作符消耗的元组数动态调整操作符调度次序,按系统截止时间确定各操作符调度时间.本文还给出了MultiFactor策略的相应算法,并通过实验证明了其性能优势.

Detection of solar radio burst intensity based on a mod ified multifactor SVM algorithm

To realize the automatic detection of solar radio burst(SRB)intensity,detection based on a modified multifactor support vector machine(SVM)algorithm is proposed.First,the influence of SRB on global navigation satellite system(GNSS)signals is analyzed.Feature vectors,which can reflect the SRB intensity of stations,are also extracted.SRB intensity is classified according to the solar radio flux,and different class labels correspond to different SRB intensity types.The training samples are composed of feature vectors and their corresponding class labels.Second,training samples are input into SVM classifiers to one-against-one training to obtain the optimal classification models.Finally,the optimal classification model is synthesized into a modified multifactor SVM classifier,which is used to automatically detect the SRB intensity of new data.Experimental results indicate that for historical SRB events,the average accuracy of SRB intensity detection is greater than 90%when the solar incident angle is higher than 20°.Compared with other methods,the proposed method considers many factors with higher accuracy and does not rely on radio telescopes,thereby saving cost.

Multifactor heart failure in the elderly:a proposal for cooperative research

Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalence in the developed countries. In the United States, the prevalence of CHF at age 50 years is 1.0%, whereas it reaches 7.5% at age 80years. In the United Kingdom, the prevalence of CHF is5.0% at age 60-70 years, and 10-20% at age 80 years. The situation is similar in Italy and Portugal. Despite being a developing country in Asia, China has experienced rapid progress in acquiring medical knowledge and advancing techniques in recent years. Due to the markedly declined mortality of acute myocardial infarction (AMI) as well as the aging of Chinese population, about four million Chinese have CHF with a prevalence of 0.9%, most of whom are 60 years of age and older.……

Multifactor dimensionality reduction analysis of syndrome characteristics of chronic persistent asthma

Objective:To analyze the syndrome characteristics in patients with chronic persistent asthma.Methods:365 patients(121 males,244 females,60.829.1 years old)with chronic persistent asthma were enrolled in this cross-sectional study.The information of syndrome,symptoms,signs,tongue coating and pulse were collected from all patients.The syndrome characteristics of chronic persistent asthma were examined through the multifactor dimensionality reduction(MDR)analysis and the results were verified by the Chi-square test.Results:The results of the MDR analysis and the Chi-square test showed the following positive correlation of the interaction among:the deficiency syndrome of the lung and spleen and deep pulse,disinclination to talk due to lack of qi,fatigue,lassitude and thick tongue coating;the deficiency syndrome of the lung and kidney and dizziness and disinclination to talk due to lack of qi,fatigue,lassitude and pallid complexion;the syndrome of phlegm-heat obstructing the lung and rapid pulse,abdominal distension,disinclination to talk due to lack of qi,frequent urination and lassitude;the syndrome of phlegm-dampness obstructing the lung and disinclination to talk due to lack of qi,greasy coating,fatigue and lassitude.(P<.05 for all).Conclusion:The syndrome of chronic persistent asthma is characterized by fatigue and lassitude due to dysfunction of the lung,spleen and kidney.

Functional zoning in national parks under multifactor trade-off guidance:A case study of Qinghai Lake National Park in China

Functional zoning is an important mechanism for achieving national park planning and management objective.Better functional zoning is of great significance to the protection of ecosystem legitimacy and integrity,the appropriate utilization of resources,community integration,and feasible management.In the present study,the proposed Qinghai Lake National Park is the research object.Based on the critical goal of ecological protection,the importance of ecosystem service functions and the ecological sensitivities were evaluated.The results showed that the ecosystem service functions and the ecological sensitivity of the whole region are high.Among them,lake,river and wetland as the most strictly protected ecosystems account for the highest proportion.Then this study divided the proposed Qinghai Lake National Park into five functional areas through grid calculations,spatial analysis and multifactor trade-off.The results indicated that the goal of functional zoning for national park is to maximize the overall utility of park protection value and its comprehensive functions based on its spatial units with different functions,management and control requirements.The zoning scheme addresses the lack of sustainable development in Qinghai Lake National Park due to ecological environmental changes and single-resource zoning with resource protection as the primary goal.This study can serve as a reference for spatial functional zoning methods of national land parks,nature reserves and other natural protected areas.

A modified simplex method for multifactor optimization of selectivity in gas chromatography

A computer-assisted advanced simplex method is presented for the simultaneous optimization of multifactor (stationary phase loading, carrier gas dow rate and column temperature) for separation of ten compounds in gas chromatography. A three factors factorial design was used. The method was based on a special polynomial established from fifteen preliminary runs, using resolution as the selection criterion, with connection to a general simplex method. Excellent agreement is found between the predicted data and the experimental results, and most of experiments required in the general simplex method can be omitted.

Incorporating Convexity in Bond Portfolio Immunization Using Multifactor Model:A Semidefinite Programming Approach

Bond portfolio immunization is a classical issue in finance. Since Macaulaygave the concept of duration in 1938, many scholars proposed different kinds of duration immunization models. In the literature of bond portfolio immunization usingmultifactor model, to the best of our knowledge, researchers only use the first-orderimmunization, which is usually called as duration immunization, and no one hasconsidered second-order effects in immunization, which is well known as “convexity” in the case of single-factor model. In this paper, we introduce the second-orderinformation associated with multifactor model into bond portfolio immunization andreformulate the corresponding problems as tractable semidefinite programs. Bothsimulation analysis and empirical study show that the second-order immunization strategies exhibit more accurate approximation to the value change of bonds and thusresult in better immunization performance.

我国城镇污水处理厂污泥产率系数现状及影响因素分析

以我国城镇污水处理厂生态环境统计和监测数据为基础,分析了我国城镇污水处理厂经验污泥产率系数(YQ)和以去除COD导致的污泥增殖来计算的污泥产率系数(YCOD),研究了进水COD、设计处理规模、处理工艺、区域分布等单一因素以及多因素与污泥产率系数的响应关系。结果表明,我国城镇污水处理厂YQ平均值为1.33×10-4 t/m3,YCOD平均值为0.81 kg/kg,YQ、YCOD总体呈正偏态分布;YQ平均值与进水COD、设计处理规模正相关,YCOD平均值与进水COD、设计处理规模负相关;YQ、YCOD平均值对应的COD区间范围为150~250 mg/L,设计处理规模为1×104~1×105 m3/d的污水处理厂YQ、YCOD与平均值最为接近,相对偏差分别为2.8%、-4.3%;A2/O工艺、氧化沟类、普通活性污泥法、A/O工艺的YQ、YCOD与平均值接近,相对偏差范围分别为-1.8%~1.9%、-2.3%~5.8%;华东和华中地区的YQ,华东、西南地区YCOD与平均值基本持平;多因素方差分析显示进水COD为YQ和YCOD的显著影响因素。

基于刚柔耦合模型的黄鳝剖切机仿真及试验

针对目前黄鳝人工剖切费时、费力且安全性差等难点,该研究以体表黏滑的鲜活黄鳝为研究对象,设计了一款小型黄鳝自动剖切机。首先,测定了黄鳝基本物理参数以及相关力学参数。其次,基于刚柔耦合原理,将黄鳝鱼体与夹持轮、滑道的接触等效为刚度—阻尼模型,运用Abaqus与Adams仿真软件建立其刚柔耦合模型。以鱼体输送时间、输出速度、夹持力、整机振动为试验指标,探究弹簧刚度、滑道倾角、夹持轮转速等单因素对试验指标的影响。结果表明,随着弹簧刚度增大,夹持力先增大后降低,整机振动幅度降低,而输送时间和输出速度影响不大。随着滑道倾角增大,鱼体输出时间减少,而输出速度、夹持力、整机振动增大。随着夹持轮转速的增大,鱼体输送时间、输出速度、夹持力、整机振动均增大。在单因素分析基础上进行多因素分析,获得优化工况为夹持轮转速600 r/min、弹簧刚度1.2×10^(3) N/m、滑道倾角16°。最后,开展黄鳝自动剖切机加工试验,测得的振动参数以及鱼体输出速度与仿真结果接近,且鲜活黄鳝在优化工况下剖切效果良好。研究结果为小型黄鳝剖切机设计提供参考。

开放性眼外伤玻璃体切割手术预后及影响因素

目的探讨开放性眼外伤行玻璃体切割手术(PPV)治疗的预后情况,并对其相关影响因素进行分析。方法回顾性研究2013-01至2022-12在武警四川总队医院、乐山市眼科中心、成都中医药大学附属眼科医院行PPV治疗的开放性眼外伤患者241例(241眼)的临床资料。记录术前临床特征,包括性别、年龄、外伤类型、外伤分区、眼内异物、视力、眼压、相对性传入性瞳孔障碍、受伤至PPV时间(受伤~手术时间)、感染性眼内炎和组织受累情况。根据患者情况制定相应的PPV方案,术后随访6个月,每次随访记录视力、眼压、屈光介质情况,视网膜复位情况,眼球保留和摘除情况。根据末次随访结果评判手术预后情况。采用多因素回归分析术前临床特征与手术预后的相关性。结果241眼中,解剖痊愈113眼(46.9%),功能痊愈93眼(38.6%),总治愈206眼(85.5%),未愈35眼(14.5%),眼球摘除17眼(7.1%)。多因素回归分析显示总治愈率与外伤类型、外伤分区、受伤~手术时间相关,眼球摘除率与外伤类型、术前视力、受伤~手术时间相关。结论PPV治疗开放性眼外伤疗效显著,外伤类型、外伤分区、术前视力和受伤~手术时间是影响手术预后的相关因素。

Association between Gene Polymorphisms and SNP-SNP Interactions of the Matrix Metalloproteinase 2 Signaling Pathway and the Risk of Vascular Senescence

Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.

Risk factors and survival prediction model establishment for prognosis in patients with radical resection of gallbladder cancer

BACKGROUND Gallbladder cancer(GBC)is the most common malignant tumor of the biliary system,and is often undetected until advanced stages,making curative surgery unfeasible for many patients.Curative surgery remains the only option for long-term survival.Accurate postsurgical prognosis is crucial for effective treatment planning.tumor-node-metastasis staging,which focuses on tumor infiltration,lymph node metastasis,and distant metastasis,limits the accuracy of prognosis.Nomograms offer a more comprehensive and personalized approach by visually analyzing a broader range of prognostic factors,enhancing the precision of treatment planning for patients with GBC.AIM A retrospective study analyzed the clinical and pathological data of 93 patients who underwent radical surgery for GBC at Peking University People's Hospital from January 2015 to December 2020.Kaplan-Meier analysis was used to calculate the 1-,2-and 3-year survival rates.The log-rank test was used to evaluate factors impacting prognosis,with survival curves plotted for significant variables.Single-factor analysis revealed statistically significant differences,and multivariate Cox regression identified independent prognostic factors.A nomogram was developed and validated with receiver operating characteristic curves and calibration curves.Among 93 patients who underwent radical surgery for GBC,30 patients survived,accounting for 32.26%of the sample,with a median survival time of 38 months.The 1-year,2-year,and 3-year survival rates were 83.87%,68.82%,and 53.57%,respectively.Univariate analysis revealed that carbohydrate antigen 19-9 expre-ssion,T stage,lymph node metastasis,histological differentiation,surgical margins,and invasion of the liver,ex-trahepatic bile duct,nerves,and vessels(P≤0.001)significantly impacted patient prognosis after curative surgery.Multivariate Cox regression identified lymph node metastasis(P=0.03),histological differentiation(P<0.05),nerve invasion(P=0.036),and extrahepatic bile duct invasion(P=0.014)as independent risk factors.A nomogram model with a concordance index of 0.838 was developed.Internal validation confirmed the model's consistency in predicting the 1-year,2-year,and 3-year survival rates.CONCLUSION Lymph node metastasis,tumor differentiation,extrahepatic bile duct invasion,and perineural invasion are independent risk factors.A nomogram based on these factors can be used to personalize and improve treatment strategies.

基于SSA-CG-Attention模型的多因素采煤工作面涌水量预测

矿井工作面涌水量预测对确保矿山安全、优化资源配置、提高工作效率等都具有重要作用。为提高预测结果的准确性和稳定性,基于钻孔水位和微震能量数据与涌水量的强关联性,选择其作为多因素特征变量,提出SSA-CG-Attention多因素矿井工作面涌水量预测模型。该模型在门控循环单元(GatedRecurrentUnit,GRU)提取时序特征的基础上,与卷积神经网络(ConvolutionalNeuralNet-work,CNN)融合形成新的网络结构提取数据的有效非线性局部特征,并且加入注意力机制(Atten-tion),在预测过程中将注意力集中在输入元素上,提高模型的准确性。最后通过麻雀搜索算法(Spar-row Search Algorithm,SSA)优化模型参数,避免局部最优解的问题。将提出的模型分别与传统的BP神经网络、LSTM、GRU单因素涌水量预测模型以及MLP、SLP、SVR、LSTM、GRU、SSA-LSTM、SSA-GRU多因素涌水量预测模型的预测结果进行对比分析,结果表明:SSA算法以最少迭代次数快速寻优,避免了局部最优解的缺陷;SSA-CG-Attention多因素涌水量预测模型整体预测指标绝对误差(E_(MA))、均方根误差(E_(RMS))以及平均绝对百分比误差(E_(MAP))分别为5.24 m^(3)/h、7.25 m^(3)/h、6%,指标方差和为8.90。相较于其他预测模型预测精度更高,相较于单因素涌水量预测模型,多因素涌水量预测模型预测结果更加稳定。研究结果为矿井工作面涌水量预测提供了新的思路与方法,对矿井工作面涌水量预测及防控有着借鉴与指导作用,具有一定的理论价值和现实意义。

脂肪细胞因子通路基因多态性与肥胖儿童非酒精性脂肪性肝病的关联

目的:非酒精性脂肪性肝病(non-alcoholic fatty liver disease,NAFLD)存在明显的遗传易感性,脂肪细胞因子通过参与胰岛素抵抗和肝脏脂肪变性等过程,在NAFLD的发生和发展中发挥重要作用,但参与脂肪细胞因子通路的基因与NAFLD之间的关联仍不明确。本研究旨在探索脂肪细胞因子通路的基因多态性位点及其交互作用与肥胖儿童NAFLD的关联。方法:采用病例对照研究,将肥胖儿童分为NAFLD组和对照组。采集受试者外周静脉血2 mL,提取DNA后采用多重PCR和高通量测序对脂肪细胞因子通路的14个单核苷酸多态性(single nucleotide polymorphism,SNP)进行分型检测。采用单因素及多因素Logistic回归分析各SNP与肥胖儿童NAFLD的关联。基于显性模型,联合使用交叉分析和Logistic回归分析相加或相乘交互作用。采用广义多因子降维法(generalized multifactor dimensionality reduction,GMDR)检测14个SNP之间基因-基因交互作用与肥胖儿童NAFLD之间的关联。结果:共纳入1 022例儿童,NAFLD组与对照组各511例。在调整年龄、性别、BMI后,多因素Logistic回归结果显示:PPARG rs1801282在3个遗传模型中与肥胖儿童NAFLD存在关联,分别是杂合子模型(CG vs CC,OR=0.58,95%CI 0.36~0.95,P=0.029)、显性模型(CG+GG vs CC,OR=0.62,95%CI 0.38~1.00,P=0.049)、超显性模型(CC+GG vs CG,OR=1.72,95%CI 1.06~2.80,P=0.028);PRKAG2 rs12703159在4个遗传模型中与肥胖儿童NAFLD存在关联,分别是杂合子模型(CT vs CC,OR=1.51,95%CI 1.10~2.07,P=0.011)、显性模型(CT+TT vs CC,OR=1.50,95%CI 1.10~2.03,P=0.010)、超显性模型(CC+TT vs CT,OR=0.67,95%CI 0.49~0.92,P=0.012)、加性模型(CC vs CT vs TT,OR=1.40,95%CI 1.07~1.83,P=0.015)。但PPARG rs1801282与PRKAG2 rs12703159间的相乘及相加交互作用均与肥胖儿童NAFLD不存在关联。经GMDR分析,调整年龄、性别、BMI后,14个SNP之间的交互作用均无统计学意义(均P>0.05)。结论:PPARG rs1801282、PRKAG2 rs12703159突变型与肥胖儿童NAFLD存在关联,但未发现SNP交互作用与肥胖儿童NAFLD之间的关联。

谷氨酸通路基因多态性交互作用与快感缺失的关联研究

目的·探究谷氨酸通路基因-基因交互作用与快感缺失的关联。方法·纳入2017年1月-2020年8月在上海交通大学医学院附属精神卫生中心门诊及病房招募的279例精神分裂症(schizophrenia,SZ)患者、236例重型抑郁障碍(major depression disorder,MDD)患者,以及在社区招募的236例健康对照(healthy control,HC)为研究对象。收集并比较3组被试的一般人口学资料及临床特征。采用时间性愉快体验量表(Temporal Experience of Pleasure Scale,TEPS)中文版评估3组的愉快体验能力。采用广义多因子降维(generalized multifactor dimensionality reduction,GMDR)法建立谷氨酸通路基因(NOS1AP、GSK3β、DAOA、DISC1及GRIN2A)单核苷酸多态性(single nucleotide polymorphism,SNP)交互作用模型,依据该模型将SZ及MDD患者分为高风险组和低风险组,并对其愉快体验能力的差异进行组间比较,以分析基因-基因交互作用对快感缺失的影响。结果·年龄、受教育年限在3组间的差异具有统计学意义,首发年龄、病程在SZ、MDD组间的差异具有统计学意义(均P=0.000)。3组被试在总体愉快体验、期待性愉快体验及即时性愉快体验间差异均具有统计学意义(均P=0.000);SZ、MDD组患者的总体愉快体验、期待性及即时性愉快体验均低于HC组(均P_(校正)=0.000),且SZ与MDD组在期待性愉快体验上具有边缘性统计学差异(P_(校正)=0.051)。通过GMDR建模发现,由DAOA-rs3916965与DISC1-rs821577组成的2位点交互作用模型对SZ患者总体愉快体验能力具有预测作用(P=0.003),由NOS1AP-rs1858232和GRIN2A-rs1014531组成的2位点交互作用模型对MDD患者期待性愉快体验能力具有预测作用(P=0.037);且SZ高风险组患者的总体愉快体验能力、MDD高风险组患者的期待性愉快体验能力均分别低于其低风险组(t=3.443,P=0.000;t=3.471,P=0.001)。结论·谷氨酸通路基因多态性交互作用可能参与了快感缺失的发生。

基于健康生态学模型的广东省老年共病患者患慢性病数量影响因素研究

背景近年来我国老年共病患者数是持续上升。随着慢性疾病数量的增加,会给老年人带来不同程度的健康损失。目前分析老年共病患者患慢性病数量的多层次因素研究尚少。目的结合慢性病的病因和发病特点,利用健康生态学模型,从不同层面探讨影响老年共病患者患慢性病数量的因素,为我国社区老年共病患者管理和防治提供依据。方法2023年2月,采用多阶段分层整群随机抽样的方法,抽取广东省社区老年(≥60岁)共病患者为调查对象。采用《老年共病患者现况及影响因素调查问卷》进行面对面询问调查,该问卷基于健康生态学模型包含个人特质层、行为特征层、人际关系层、生活和工作条件层、政策环境层。以老年共病患者患慢性病数量为因变量,根据5个层次纳入自变量,进行无序多因素Logistic回归分析。结果共发放问卷1000份,回收有效问卷987份,有效回收率为98.7%。987例老年共病患者中,同时患2种慢性病346例(35.1%),同时患3种慢性病456例(46.2%),同时患>3种慢性病185例(18.7%)。无序多因素Logistic回归分析结果显示,以同时患2种慢性病的老年共病患者为对照,患慢性病的时间<6年和6~10年、本地城镇户口是老年共病患者患3种慢性病的危险因素(P<0.05),OR(95%CI)分别为2.100(1.284~3.435)、1.948(1.201~3.158)、4.103(1.496~11.250);每天均可以保证至少6 h睡眠、自评健康状况比较好、每天服药1~3种类型、经常参加社会活动、初中及以下和高中/中专学历、有城镇职工医疗保险/城乡居民医疗保险是老年共病患者患3种慢性病的保护因素(P<0.05),OR(95%CI)分别为0.528(0.322~0.867)、0.570(0.325~0.998)、0.385(0.261~0.569)、0.348(0.208~0.582)、0.412(0.175~0.972)、0.486(0.298~0.790)、0.392(0.242~0.634);男性、1周运动3次以下是老年共病患者患3种以上慢性病的危险因素(P<0.05),OR(95%CI)分别为2.563(1.634~4.021)、2.990(1.429~6.256);每天均可以保证至少6 h睡眠、自评健康状况比较好和一般、每天服药1~3种类型、年平均收入≤3万元和>3~5万元、有城镇职工医疗保险/城乡居民医疗保险是老年共病患者患3种以上的慢性病的保护因素(P<0.05),OR(95%CI)分别为0.300(0.159~0.565)、0.247(0.125~0.487)、0.448(0.240~0.837)、0.288(0.178~0.467)、0.318(0.155~0.654)、0.489(0.293~0.816)、0.416(0.229~0.755)。结论广东省老年共病患者同时患2~3种慢性病的比例较高(占80%以上)。影响老年共病患者患慢性病数量的因素复杂,包括性别、患慢性病时间、运动情况、睡眠情况、自评健康状况、服药情况、户籍类型、子女或家人督促吃药或锻炼情况、收入情况、受教育程度和医保类型,且不同共病数量的危险因素差异较大。因此,应该从不同层面采取相应的干预措施,减少老年共病患者患慢性病数量,提高其健康水平。

基于多因素造模法改良脾胃气虚型糖尿病胃轻瘫大鼠模型制备方法研究

目的:采用多因素造模法联合链脲佐菌素(STZ)配合高糖高脂饲料建立脾胃气虚型糖尿病胃轻瘫(DGP)大鼠模型,并对该模型进行评价。方法:20只SPF级Wistar大鼠依据随机数字表随机分为空白组8只和造模组12只,以多因素造模法复制脾胃气虚型大鼠模型,制定脾胃气虚型模型评价量表,将符合条件大鼠纳入实验;采用小剂量多次注射STZ联合高糖高脂饲料复制DGP大鼠模型,于实验6周末取材。观察大鼠随机血糖、体质量、胃排空率、小肠推进率;Elisa法检测血清中血清淀粉样蛋白(SAA)、D-木糖、乳酸脱氢酶(LDH)的含量;光镜下观察脾脏病理结构改变。结果:与空白组比较,造模组大鼠一般情况(精神状态、粪便、饮食量)较差、体质量降低,差异有统计学意义(P<0.05);造模组随机血糖显著升高,差异有统计学意义(P<0.01);与空白组比较,造模组胃排空率、小肠推进率、SAA、D-木糖、LDH含量降低,差异有统计学意义(P<0.05,P<0.01);光镜下显示造模组脾脏被膜增厚,红髓和白髓分界限不清,淋巴细胞减少。脾胃气虚型DGP证型评价:造模组大鼠有神疲倦怠、体质量降低、蜷缩、活动度差、眯眼、毛色暗淡、舌色偏暗等脾胃气虚证表现。结论:多因素造模法建立的大鼠模型符合脾胃气虚型DGP大鼠标准。

基于多因子进化稀疏重构的轴承故障诊断研究

针对强噪声背景下滚动轴承振动信号特征提取困难的问题,基于稀疏表示基本理论,提出一种使用多因子进化算法求解的多正则化稀疏重构降噪模型。首先,将多正则化模型的求解划分为多3个目标子任务,即l0范数约束优化主任务和l1、l1/2范数正则化额外任务,以上任务分别构成3个不同目标的多因子优化稀疏重构算法;其次,根据在进化过程中不同正则化任务的优先级,采用黄金分割搜索策略保证每个族群包含相似适应度的个体,通过两点交叉遗传算子保证样本的稀疏性特征;最后,将阈值迭代算法应用于局部搜索过程加速子任务中的种群收敛。在此理论基础之上,分别通过仿真信号和实际轴承数据验证本文方法可行性,发现在-10 dB的高斯噪声干扰下,重构信号的信噪比依然达到5 dB。试验结果表明,该方法可有效提取强噪声背景下的冲击特征,为进一步的故障诊断提供可靠先验知识。

基于PLC的玉米收获机电气控制系统优化研究

为了提高玉米收获机脱粒质量,设计了基于PLC控制系统,并采用模糊控制的方法对其进行优化。首先,基于单纵轴流玉米脱粒装置,分析滚筒轴转速、脱粒间距和收获机前进速度对于脱粒质量的影响;然后,利用三元二次通用旋转组合实验的设计方法,综合考虑滚筒轴转速,脱粒间距和收获机前进速度,建立破碎率模型。对该模型进行显著性分析,结果表明:脱粒间距对于破碎率的影响不显著,故选用滚筒轴转速和收获机前进速度作为控制量,建立模糊PLC控制系统。系统测试结果表明:系统具有较快的响应速度和较高的可靠性。