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旋耕部件是微耕机的核心部件,其耕作性能的优劣直接影响微耕机的耕作效率和作业质量。以重庆地区典型的旋耕刀辊和土壤为对象,基于离散元和多体动力学理论,设定前进速度为0.2 m·s-1,转速为110 r·min-1,耕深为150和200 mm,采用非线性粘弹性塑性接触模型,在EDEM和Recurdyn软件平台上实现了刀辊耕作过程的模拟分析;同时,依托已有的土槽试验平台,测试了相同工况下刀轴的等效扭矩。模拟与试验的对比分析结果表明：同一刀轴上不同刀盘的扭矩变化规律相似,但数值并不一致,整个刀轴所受的等效扭矩不能简单地理解为单个刀盘所受扭矩与刀盘数的乘积;耕作深度为150、200 mm时刀轴等效扭矩的变化规律一致,模拟值与试验值的最大相对误差分别为14.01%、11.49%。研究结果可为探讨旋耕刀与土壤的相互作用,优化微耕机作业性能提供参考。 相似文献
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本研究旨在克隆水牛MBD3基因,进行生物信息学分析,并构建MBD3基因的真核表达载体,为研究MBD3基因在水牛胚胎发育及诱导多能干细胞（iPSCs）中的作用奠定基础。试验从卵巢组织中提取总RNA,反转录得到cDNA,并以此为模板,应用RT-PCR克隆得到MBD3基因,测序并应用相关的生物学软件进行分析;将MBD3基因连接至真核表达载体pEGFP-C1,再将携带目的基因的重组质粒转染HEK293T细胞和水牛胎儿成纤维细胞（BFF）,利用RT-PCR及Western blotting方法分析目的基因的表达。结果表明,克隆获得了898 bp的水牛MBD3基因序列,其中编码区全长774 bp,编码257个氨基酸。通过对MBD3基因核苷酸序列的多重比对及进化树分析,MBD3基因在进化中高度保守,特别是MBD结构域,水牛与牛的同源性为100%,与人、猪、猩猩的同源性均为97%。将水牛MBD3基因真核表达载体转染HEK293T细胞和BFF,通过荧光观察、RT-PCR及Western blotting方法鉴定表明,成功构建了水牛MBD3基因的真核表达载体。本研究克隆得到了水牛的MBD3基因,并成功构建了MBD3基因的真核表达载体,为进一步研究MBD3基因在水牛胚胎发育及iPSCs诱导上的作用奠定了基础。 相似文献
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Risk factors and implications associated with renal mineralization in chronic kidney disease in cats
Pak&#x;Kan Tang Rosanne E. Jepson Yu&#x;Mei Chang Rebecca F. Geddes Mark Hopkinson Jonathan Elliott 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2022,36(2):634
BackgroundNephrocalcinosis is a pathological feature of chronic kidney disease (CKD). Its pathophysiological implications for cats with CKD are unexplored.ObjectivesIdentify nephrocalcinosis risk factors and evaluate its influence on CKD progression and all‐cause mortality.AnimalsFifty‐one euthyroid client‐owned cats with International Renal Interest Society (IRIS) stages 2‐3 azotemic CKD.MethodsRetrospective cohort study. Histopathological kidney sections were assessed for nephrocalcinosis (von Kossa stain). Nephrocalcinosis severity was determined by image analysis (ImageJ). Ordinal logistic regressions were performed to identify nephrocalcinosis risk factors. The influence of nephrocalcinosis on CKD progression and mortality risk were assessed using linear mixed model and Cox regression, respectively. Cats were categorized by their owner‐reported time‐averaged phosphate‐restricted diet (PRD) intake, where PRD comprised ≥50%, 10‐50%, or none of food intake.ResultsNephrocalcinosis was rated as mild‐to‐severe in 78.4% and absent‐to‐minimal in 21.6% of cases. Higher baseline plasma total calcium concentration (tCa; odds ratio [OR] = 3.07 per 1 mg/dL; P = .02) and eating a PRD (10%‐50%: OR = 8.35; P = .01; ≥50%: OR = 5.47; P = .01) were independent nephrocalcinosis risk factors. Cats with absent‐to‐minimal nephrocalcinosis had increasing plasma creatinine (0.250 ± 0.074 mg/dL/month; P = .002), urea (5.06 ± 1.82 mg/dL/month; P = .01), and phosphate (0.233 ± 0.115 mg/dL/month; P = .05) concentrations over a 1‐year period, and had shorter median survival times than cats with mild‐to‐severe nephrocalcinosis.Conclusion and Clinical ImportanceHigher plasma tCa at CKD diagnosis and PRD intake are independently associated with nephrocalcinosis. However, nephrocalcinosis is not associated with rapid CKD progression in cats. 相似文献
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DNA甲基化在基因表达调控过程中发挥重要作用,甲基结合蛋白(Methy1-Binding Domain Protein, MBD)是能特异识别甲基化位点的反式作用因子.开展植物MBD基因的功能研究对于探讨植物生长发育的表观遗传学调控机制具有重要意义.该研究构建了小麦甲基结合蛋白基因MBD3的原核表达载体pGEX-4T-MBD3,转化大肠杆菌BL21(DE3)工程菌株,在37℃,lmMIPTG浓度条件下,成功诱导表达了的GST-MBD3融合蛋白,大小为49.6kDa,这为进一步开展MBD3的蛋白纯化和功能分析奠定了基础. 相似文献
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旋耕部件是微耕机的核心部件,其耕作性能的优劣直接影响微耕机的耕作效率和作业质量。以重庆地区典型的旋耕刀辊和土壤为对象,基于离散元和多体动力学理论,设定前进速度为0.2 m·s-1,转速为110 r·min-1,耕深为150和200 mm,采用非线性粘弹性塑性接触模型,在EDEM和Recurdyn软件平台上实现了刀辊耕作过程的模拟分析;同时,依托已有的土槽试验平台,测试了相同工况下刀轴的等效扭矩。模拟与试验的对比分析结果表明：同一刀轴上不同刀盘的扭矩变化规律相似,但数值并不一致,整个刀轴所受的等效扭矩不能简单地理解为单个刀盘所受扭矩与刀盘数的乘积;耕作深度为150、200 mm时刀轴等效扭矩的变化规律一致,模拟值与试验值的最大相对误差分别为14.01%、11.49%。研究结果可为探讨旋耕刀与土壤的相互作用,优化微耕机作业性能提供参考。 相似文献
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小麦TaMBD3基因的克隆和表达 总被引：1，自引：0，他引：1
DNA甲基化(m5C)在基因表达调控过程中发挥重要作用,而甲基结合域蛋白(MBD)是能特异识别甲基化位点的反式作用因子.为了探讨小麦中MBD基因的结构与功能,以拟南芥MBD基因的EST为基础,通过电子克隆结合RT-PCR方法分离克隆了包含ORF的小麦甲基结合域蛋白基因TaMBD3.序列分析显示,TaMBD3具有典型的甲基结合域,其中包含了能与甲基化DNA相结合的保守氨基酸残基.组织表达特性分析表明,TaMBD3在幼穗和茎中的表达量高于其它组织器官.采用电子定位的方法,将TaMBD3基因初步定位在6AS1-0.35-0.65和C-6BL3-0.36两个区域. 相似文献
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SU Xiao-ping XIAO Ning LUO Xi-er LEI Wei CUI Kui-qing SHI De-shun LIU Qing-you 《中国畜牧兽医》2016,43(8):1951-1959
In this study,through cloning buffalo MBD3 gene and analyzing the biological information of MBD3 gene sequence,and constructing the expression vector of buffalo MBD3,to provide a basis for the function research of buffalo MBD3 gene on embryo development and iPCSs.The total RNA was extracted from buffalo fresh ovary,and MBD3 gene was amplified and sequenced,the sequence was systemically analysed with bioinformatics techniques.And the MBD3 CDS was cloned into the pEGFP-C1 vector.Then the recombinant plasmid pEGFP-C1-MBD3 was transferred into the HEK293T cells and buffalo fetal fibroblasts (BFF),the expression was analyzed by RT-PCR,Western blotting and fluorescence microscope.The results showed that 898 bp of MBD3 gene fragment including whole 774 bp CDS was cloned and sequenced,and encoded 257 amino acids.The multiple sequence alignment and analysis of phylogeny tree showed that MBD3 gene was highly conserved in the process of evolution.Especially the MBD domain,the MBD domain of buffalo MBD3 gene shared 100% of similar nucleotide sequence with Bos taurus,and shared 97% of similar nucleotide sequence with Homo sapiens,Sus scrofa and Pan troglodytes.The recombinant plasmids pEGFP-C1-MBD3 were transferred into HEK293T cells and BFF,fluorescence observation,RT-PCR and Western blotting were used to analyze the expression of buffalo MBD3.The results suggested that the expression vector of buffalo MBD3 gene was successfully constructed.The study laid the foundation for the function research of MBD3 on embryo development and inducing of iPCSs. 相似文献
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