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181.
耕种机械化技术是指以机械为手段,完成作物生长所需的苗床准备(耕整地)和实现播种的生产技术.对农业生产耕种技术的推广和规模化起促进和保证作用,农机具是农机化技术的载体,两者密不可分.  相似文献   
182.
Plants have evolved a sophisticated defense system that employs various hormone pathways to defend against attacks by insect pests. Cytokinin (CK) plays an important role in plant growth and stress tolerance, but the role of CKs in plant–insect interaction remains largely unclear. Here, we report that CKs act as a positive regulator in rice resistance against brown planthopper (BPH), a devastating insect pest of rice. We found that BPH feeding promotes CK biosynthesis and signaling in rice. Exogenous application of CKs significantly increased the rice resistance to BPH. Increasing endogenous CKs by knocking out cytokinin oxidase/dehydrogenase (OsCKXs) led to enhanced resistance to BPH. Moreover, the levels of the plant hormone jasmonic acid (JA) and the expression of JA-responsive genes were elevated by CK treatment and in OsCKXs knockout plants. Furthermore, JA-deficient mutant og1 was more susceptible to BPH, and CK-induced BPH resistance was suppressed in og1. These results indicate that CK-mediated BPH resistance is JA-dependent. Our findings provide the direct evidence for the novel role of CK in promoting insect resistance, and demonstrate that CK-induced insect resistance is JA-dependent. These results provide important guidance for effective pest management strategies in the future.  相似文献   
183.
举例介绍了冷却塔的选型和配管设计中应该注意的问题。  相似文献   
184.
针对冷却塔降温效果较差问题,采取了重新码放填料、调整风机转速比、增加风机叶片数量、加宽叶片直径等改进措施。多次的试运行结果表明改进措施是可行的。  相似文献   
185.
Wheat allergies are potentially life-threatening because of the high risk of anaphylaxis. Wheats belong to four genotypes represented in thousands of lines and varieties. Monitoring changes to wheat allergens is critical to prevent inadvertent ntroduction of hyper-allergenic varieties via breeding. However, validated methods for this purpose are unavailable at present. As a proof-of-concept study, we tested the hypothesis that salt-soluble wheat allergens in our mouse model will be identical to those reported for humans. Groups of Balb/cJ mice were rendered allergic to durum wheat salt-soluble protein extract (SSPE). Using blood from allergic mice, a mini hyper-IgE plasma bank was created and used in optimizing an IgE Western blotting (IEWB) to identify IgE binding allergens. The LC-MS/MS was used to sequence the allergenic bands. An ancient Aegilops tauschii wheat was grown in our greenhouse and extracted SSPE. Using the optimized IEWB method followed by sequencing, the cross-reacting allergens in A. tauschii wheat were identified. Database analysis showed all but 2 of the durum wheat allergens and all A. tauschii wheat allergens identified in this model had been reported as human allergens. Thus, this model may be used to identify and monitor potential changes to salt-soluble wheat allergens caused by breeding.  相似文献   
186.
针对拜耳法高铁赤泥无害化处置与资源化利用难题,研究了高铁赤泥中铝的赋存状态及其对铝铁分离的影响。借助XRD、铁化学物相分析、SEM-EDS等检测手段,主要关注高铁赤泥的化学组成、矿物组成以及铝的赋存状态等工艺矿物学特征。赤泥的主要组成矿物为褐铁矿、赤铁矿和铝针铁矿和钛铁矿。查明赤泥中的铁主要以针铁矿、赤铁矿的形式存在;铝主要以类质同象存在于针铁矿中,形成铝针铁矿,部分以三水铝石的形式存在,铁铝共生关系密切。赋存于针铁矿中的铝采用常规物理分选方法无法实现铝铁分离,利用磁化焙烧和悬浮焙烧预还原-电炉熔炼工艺分别尝试对高铁赤泥进行铝铁分离,磁化焙烧能够实现赤铁矿、针铁矿向磁铁矿的定向转化,但不能有效破坏铁矿物中铝的类质同象结构,无法实现铝和铁的分离,导致磁选铁精矿中TFe品位低、Al2O3含量高;悬浮焙烧预还原-电炉熔炼工艺能有效实现高铁赤泥的铁铝分离与综合利用,当原料TFe品位为46.85%、Al2O3含量为13.31%时,可获得TFe 92.86%的炼钢用生铁,同时所得到的矿渣产品可以作为生产铝酸盐水泥熟料的原料。可见,悬浮焙烧预还原-电炉熔炼工艺可以有效破坏矿石内部铝和铁类质同象的晶格结构,实现了铝铁的高效分离,为高铁赤泥的无害化处置与资源化利用提供了新途径。  相似文献   
187.
We previously found that short-term treatment (week 8 to 12 after injury) with high-dose angiotensin receptor blocker (ARB) induced the regression of existing glomerulosclerosis in 5/6 nephrectomy rats. We therefore assessed the effects of long-term intervention with ARB vs. nonspecific antihypertensives in this study. Adult rats underwent 5/6 nephrectomy and renal biopsy 8 weeks later. The rats were then divided into three groups with equivalent renal function and glomerular sclerosis and treated with high-dose losartan (ARB), nonspecific antihypertensive triple-therapy (TRX), or left untreated (Control) until week 30. We found that blood pressure, serum creatinine levels, and glomerulosclerosis were lower at sacrifice in ARB and TRX vs. Control. Only ARB reduced proteinuria and maintained the density of WT-1-positive podocytes. Glomerular tufts showed more double-positive cells for CD44, a marker of activated parietal epithelial cells, and synaptopodin after ARB vs. TRX or Control. ARB treatment reduced aldosterone levels. ARB-treated rats had significantly improved survival when compared with TRX or Control. We conclude that both long-term ARB and triple-therapy ameliorate progression, but do not sustain the regression of glomerulosclerosis. ARB resulted in the superior preservation of podocyte integrity and decreased proteinuria and aldosterone, linked to increased survival in the uremic environment.  相似文献   
188.
Efficient electron transport layers(ETLs)not only play a crucial role in promoting carrier separation and electron extraction in perovskite solar cells(PSCs)but...  相似文献   
189.
Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.  相似文献   
190.
采用曝气生物滤池(BAF)对受污染水源水进行了除氨氮效果研究,结果表明,当原水氨氮质量浓度在0.240~1.407 mg/L范围内时,氨氮平均去除率为83%,进水氨氮的质量浓度人工增加至O.717~12.455 mg/L时,氨氮平均去除率为88%,具有较好的氨氮去除效率和抗冲击负荷能力;同时探讨了进水氨氮容积负荷对氨氮去除效果的影响.  相似文献   
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