Foliar application of strigolactones improves the desiccation tolerance,grain yield and water use efficiency in dryland wheat through modulation of non-hydraulic root signals and antioxidant defense

Non-hydraulic root signals(nHRS)are affirmed as a unique positive response to soil drying,and play a crucial role in regulating water use efficiency and yield formation in dryland wheat production.Strigolactones(SLs)can enhance plant drought adaptability.However,the question of whether strigolactones enhance grain yield and water use efficiency by regulating nHRS and antioxidant defense systems in dryland wheat remains unanswered.In this study,pot experiments were conducted to investigate the effects of strigolactones on nHRS,antioxidant defense system,and grain yield and water use efficiency in dryland wheat.The results showed that external application of SLs increased drought-induced abscisic acid(ABA)accumulation and activated an earlier trigger of nHRS at 73.4% field capacity(FC),compared to 68.5%FC in the control group(CK).This phenomenon was mechanically associated with the physiological mediation of SLs.The application of SLs significantly enhanced the activities of leaf antioxidant enzymes,reduced ROS production,and mitigated oxidative damage to lipid membrane.Additionally,root biomass,root length density,and root to shoot ratio were increased under strigolactone treatment.Furthermore,exogenous application of SLs significantly increased grain yield by 34.9%under moderate drought stress.Water use efficiency was also increased by 21.5% and 33.3% under moderate and severe drought conditions respectively,compared to the control group(CK).The results suggested that the application of strigolactones triggered earlier drought-sensing mechanism and improved the antioxidant defense ability,thus enhancing grain yield and water use efficiency in dryland wheat production.

Modulation of Root Signals in Relation to Stomatal Sensitivity to Root-sourced Abscisic Acid in Drought-affected Plants

Stomatal sensitivity to root signals induced by soil drying may vary between environments and plant species. This is likely to be a result of the interactions and modulations ámong root signals. As a stress signal, abscisic acid （ABA） plays a central role in root to shoot signaling, pH and hydraulic signals may interact with ABA signals and thus, jointly regulate stomatal responses to changed soil water status, pH itself can be modified by several factors, among which the chemical compositions in the xylem stream and the live cells surrounding the vessels play crucial roles. In addition to the xylem pH, more attention should be paid to the direct modulation of leaf apoplastic pH, because many chemical compositions might strongly modify the leaf apoplastic pH while having no significant effect on the xylem pH. The direct modulation of the ABA signal intensity may be more important for the regulation of stomatal responses to soil drying than the ABA signal per se. The ABA signal is also regulated by the ABA catabolism and the supply of precursors to the roots if a sustained root to shoot communication of soil drying operates at the whole plant level. More importantly, ABA catabolism could play crucial roles in the determination of the fate of the ABA signal and thereby control the stomatal behavior of the root-sourced ABA signal.

Effects of Root Pruning on Non-Hydraulic Root-Sourced Signal, Drought Tolerance and Water Use Efficiency of Winter Wheat

Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals （nHRS）, drought tolerance and water use efficiency of winter wheat （Triticum aestivum）. The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots （1.06 and 0.94 mmol g-1 s-1, respectively）. The soil water content （SWC） at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants （61.1-44.6% field water capacity） than for intact root plants （57.9-46.1% field water capacity）. At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield （F PS II ）, the maximum photochemical efficiency of PS II （F v /F m ）, coefficient of photochemical quenching （qP）, and coefficient of non-photochemical quenching （NPQ）, in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency （WUE） than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.

Relationship Between Root Chemical Signals and Grain Quality of Rice

This study was designed to elucidate the relationship between root chemical signals and the quality of rice. Various rice genotypes were used. Zeatin （Z） ＋ zeatin riboside （ZR）, abscisic acid （ABA）, 1-aminocylopropane -1-carboxylic acid （ACC）, and organic acids in roots during grain filling and the appearance quality, cooking/eating quality were investigated. The correlations among them were analyzed. The results showed that Z ＋ ZR concentrations in the roots at mid- and lategrain-filling stages were significantly and positively correlated with the gel consistency and alkali spreading value （r = 0.72^＊ - 0.90^＊＊）, whereas negatively correlated with the amylose content （r = -0.68^＊ - -0.78^＊＊）. ABA concentrations in roots at mid- grain-filling stage were significantly and negatively correlated with the gel consistency and alkali spreading value （r = -0.90^＊＊-0.91^＊＊）, and positively correlated with the amylose content （r = 0.87^＊＊）. ACC concentrations in root exudates at mid-grain-filling stage were very significantly correlated with the percentage of chalky grains and chalkiness （r = 0.97^＊＊ - 0.98^＊＊）, and those at late-grain-filling stage Were significantly correlated with chalkiness and chalky size （r = 0.69^＊ - 0.96^＊＊）. The more the malic acid and succinic acid exuded from roots for a cultivar, the greater the breakdown values and the smaller the setback values in the starch profile, and the results were reversed for a cultivar with more tartaric acid and citric acid exuded from roots during the grain-filling period. The cultivar with more lactic acid in exudates had smaller gel consistency and alkali spreading values, but had greater amylose content. When roots were treated with exogenous ZR, ABA, and ACC during grain filling, effects of the chemicals on the rice quality were consistent with the relationships of the endogenous hormones （Z ＋ ZR, ABA, and ACC） with the quality indexes. Using rape cake as organic fertilizer can increase the concentrations of malic acid and succinic acids exuded from roots as well as the breakdown value in starch profile and reduce the setback value. The results suggest that root chemical signals play important roles in the formation of rice quality, and dee quality could be improved through regulating the signals.

A Modified Root-MUSIC Algorithm for Signal DOA Estimation

This paper presents a modified Root-MUSIC algorithm by which the signal DOA estimation performance can be improved when the snapshot number is limited. The operation principlesof this algorithm are described in detail. It is also pointed out theoretically that this is equivalentto have increased the snapshot number and can make the DOA estimation better. Finally, somesimulating results to verify the theoretical analyses are presented.

Role of a Signalling System in Gene Interaction in Inheritance of Root System Characteristics of Arabidopsis thaliana (L.) Heynh.

The central problem of genetics is gene interaction since genes in the course of individual organism development interact with other genes, that’s why their effects may change. Studies for the last 100 years managed to discover that the entire diversity of inter-gene interactions is presented in four major forms: complementarity, epistasis, polymery, and modifying effect of genes. However, gene interaction mechanism which is reflected on the segregation nature of variously crossed hybrids has not been sufficiently studied. Exclusive of molecular genetics, biochemistry and physiology, a genetic analysis of inheritance of characteristics in gene interaction taken by itself cannot reveal nature of this interaction. Lately, molecular-genetic and physiological studies on A. thaliana mutants have enabled to isolate and sequence a wide range of genes controlling certain links of the signalling chain. At the same time, effect of the plant development regulation signalling system on interaction of these genes in inheritance of characteristics of Arabidopsis root system haven’t been studied so far which was a cause for our studies. Gene interaction problem is closely related to the plant development regulation signalling system. Mechanism involved in gene interaction may be explained based on current idea of molecular principles of biological response. Affected by mutations occurring in various genes that control certain links of the signalling chain, signalling path to the cell nucleus and response are blocked partially or in full which leads to distortion in expression of the characteristic on the plant level in general or its organ level. Such phenomenon is observed in realization of many characteristics in animals and plants, including in A. thaliana. In inheritance of such characteristics, as a rule, both allelic, and non-allelic gene interactions are observed. Results of a study of the plant signalling system interconnection and gene interaction in inheritance of characteristics of Arabidopsis root system are presented. It is established that complementary interaction of genes RHD3 and SAR1 is observed in the second crossing generation for plants of rhd3-1 × sar-1 mutant lines. When gpa1-3 × slr-1 mutant-line plants are crossed, recessive epistasis (slr-1 slr-1 > GPA1_) occurs in F2 generation. Polymeric interaction of genes SHY2 and MSG1 is observed in F2 in crossing of shy2-2 × msg1-2 mutant-line plants.

拟南芥根的辐射形态相关基因SHORT-ROOT研究进展

从模式植物拟南芥中克隆得到的SHORT-ROOT基因(SHR)被证明参与根部形态建成途径。目前已知SHR是与根辐射形态直接相关的重要调控因子,同时也参与维持根尖分生组织的活性。SHR既作为转录因子启动下游基因的表达,又作为短程信号调节根的发育。本文综述了SHR相关研究进展,并展望其研究前景。

基于Root-MUSIC和Adaline神经网络的间谐波参数估计

为了提高电力系统间谐波分析的精度和分辨率,提出基于求根多重信号分类法(root-MUSIC)和自适应线性神经网络的间谐波参数估计方法.该算法利用求根多重信号分类法估计信号中谐波和间谐波的个数及频率,将谐波和间谐波的频率作为Adaline神经网络的输入进行学习,用得到的权值确定谐波和间谐波的幅值和相位;将频率作为权值在改进的Adaline神经网络中参与学习,估计谐波和间谐波的频率、幅值和相位.Matlab仿真结果表明,该算法频率分辨率高、检测准确、收敛快;当频率估计准确时,基本Adaline神经网络与改进的Adaline神经网络具有相近的检测精度,且前者的实时性更好.

用于非圆信号二维测向的扩展Root-MUSIC算法

利用双平行线阵的阵列结构,提出了用于非圆信号二维测向的扩展root-MUSIC(ERM)算法。ERM算法估计得到的俯仰角与方位角一一对应,自动配对,无需搜索,其可测向信号数大于子阵阵元数,方位测角精度优于同样基于双平行线阵的二维测向波达方向矩阵法(DOAM),俯仰测角精度在低信噪比下优于DOAM算法,俯仰角兼并时算法仍有效。

构网型直驱风机的小信号建模及动态频率支撑策略

针对传统构网型直驱风机在大扰动下的频率和功率振荡较大的问题,提出一种动态频率支撑策略。首先对构网型直驱风机进行了详细的小信号建模。其次,通过主导特征根轨迹分析有功频率控制以及交流电压控制环节中参数对频率变化特性的影响,进而提出一种灵活改变控制参数的动态频率支撑策略。最后,在Matlab/Simulink仿真平台上搭建仿真模型,验证了小信号建模的正确性和所提策略的有效性,表明所提策略能有效减小动态过程中的频率和功率振荡。

基于Root-MUSIC法的轧辊偏心参数估计（英文）

针对轧辊偏心信号是混杂在各种随机干扰中的复杂高频周期信号,因FFT法对信号分析的局限性,提出了一种Root-MUSIC(Multiple Signal Classification)法和Prony法相结合的轧辊偏心信号估计新方法。利用Root-MUSIC法准确估计出偏心谐波的频率及谐波的个数,同时使用Prony方法估计出偏心信号的各次谐波幅值和相位。仿真结果验证了可行性和有效性,在信噪比较低的情况下仍能准确地同时估计出偏心谐波的频率、幅值及相位,尤其在频率分辨率和抗噪声上比FFT法具有优越性。

薏苡附子败酱散通过抗三结构域蛋白21-Toll样受体4-t-核因子-κB信号通路对类风湿关节炎MH7A细胞的影响

目的观察不同浓度薏苡附子败酱散对肿瘤坏死因子-α(TNF-α)诱导的类风湿关节炎成纤维细胞(MH7A)增殖、凋亡及炎症反应的影响,探究其作用机制。方法2022年2―8月,大鼠用不同浓度薏苡附子败酱散及蒸馏水灌胃制备含药血清;20μg/L的TNF-α处理的MH7A细胞记为TNF-α组,TNF-α+含药血清处理的MH7A细胞记为薏苡附子败酱散低浓度组、薏苡附子败酱散中浓度组、薏苡附子败酱散高浓度组,正常培养的MH7A细胞标记为对照组。细胞计数试剂盒(CCK8)、流式细胞术、酶联免疫吸附测定(ELISA)检测细胞的存活、凋亡及白细胞介素(IL)-1β、干扰素(IFN)-γ;蛋白质印迹法(WB)检测基质金属蛋白酶(MMP)-3、MMP-9、抗三结构域蛋白21(TRIM21)、Toll样受体4(TLR4)、t-核因子(NF)-κB p65、磷酸化(p)-NF-κB p65、p-NF-κB抑制因子(IκB)-α和t-IκB-α蛋白表达。pcDNA 3.1组(转染空载体)、pcDNA+TRIM21组(转染pcDNA 3.1+TRIM21)、薏苡附子败酱散中浓度+si-con组(转染si-con+4.70 g/kg含药血清)、薏苡附子败酱散中浓度+si-TRIM21组(转染si-TRIM21+4.70 g/kg含药血清)。结果与对照组相比,TNF-α组细胞存活率(105.07±1.90比185.67±3.06)、TRIM21(0.56±0.02比0.68±0.04)、MMP-3(0.18±0.00比0.63±0.02)、MMP-9(0.39±0.01比0.82±0.01)、TLR4(0.25±0.02比0.68±0.07)、p-NF-κB p65(0.24±0.01比0.68±0.06)、p-IκB-α(0.22±0.01比0.55±0.04)蛋白表达和IL-1β(31.65±0.66比101.93±0.60)、IFN-γ(8.53±0.16比63.76±1.35)含量均显著升高,凋亡率(6.54±0.06比1.17±0.08)均显著降低;与TNF-α组相比,薏苡附子败酱散低浓度组(185.67±3.06比153.77±3.09;0.68±0.04比0.37±0.02;0.63±0.02比0.47±0.02;0.82±0.01比0.73±0.01;103.2±0.7比92.93±0.85;66.3±1.45比54.47±1.46;0.68±0.07比0.53±0.05;0.68±0.06比0.53±0.06;0.55±0.04比0.47±0.01;1.84±0.07比6.67±0.28)、薏苡附子败酱散中浓度组(185.67±3.06比136.23±1.57;0.68±0.04比0.57±0.02;0.63±0.02比0.37±0.02;0.82±0.01比0.57±0.00;103.2±0.7比86.4±0.75;66.3±1.45比38.1±0.92;0.68±0.07比0.43±0.07;0.68±0.06比0.59±0.01;0.55±0.04比0.40±0.03;1.84±0.07比9.59±0.29)、薏苡附子败酱散高浓度组(185.67±3.06比143.47±1.50;0.68±0.04比0.47±0.02;0.63±0.02比0.41±0.05;0.82±0.01比0.62±0.00;103.2±0.7比89.63±0.42;66.3±1.45比40.17±0.90;0.68±0.07比0.51±0.06;0.68±0.06比0.69±0.07;0.55±0.04比0.41±0.02;1.84±0.07比8.89±0.08)细胞存活率、TRIM21、MMP-3、MMP-9蛋白和IL-1β、IFN-γ含量及TLR4、p-NF-κB p65、p-IκB-α蛋白表达均显著降低,凋亡率均显著升高(P<0.05);与pcDNA组相比,pcDNA+TRIM21组细胞TRIM21蛋白表达(0.24±0.03比0.51±0.04)、细胞凋亡率(1.61±0.11比12.43±0.61)均显著升高,MMP-3(0.64±0.02比0.41±0.04)、MMP-9(0.82±0.03比0.45±0.02)、IL-1β(110.63±0.55比90.93±0.60)、IFN-γ(64.5±0.82比48.1±1.25)及细胞存活率(179.03±0.74比120.07±0.60)均显著降低;敲减TRIM21显著抑制薏苡附子败酱散中浓度对损伤细胞的治疗作用且显著升高TLR4(0.45±0.06比0.61±0.02)、p-NF-κB p65(0.49±0.02比0.56±0.02)、p-IκB-α(0.38±0.01比0.62±0.01)的蛋白表达。结论薏苡附子败酱散增强TNF-α诱导的MH7A细胞的生存能力,其作用机制与上调TRIM21抑制TLR4-NF-κB信号通路活性有关。

L型互质阵的虚拟共轭插值二维DOA估计方法

针对现有互质阵DOA估计方法无法充分利用非连续阵元信息和信号时域信息,而导致的DOA估计精度低、虚拟阵列的阵列孔径小和自由度少的问题,本文提出了一种L型互质阵的虚拟共轭插值二维DOA估计方法。该方法首先以L型互质阵的阵列接收数据为基础,通过求解其互相关函数,来构造虚拟共轭增广阵列的接收数据矩阵;然后通过阵列插值补零和选取协方差矩阵非零列,得到含有部分缺失项的虚拟均匀线阵接收数据矩阵,并依据原子范数的思想,构造无网格凸优化问题,对虚拟均匀线阵协方差矩阵的缺失项进行填充,再使用求根多重信号分类方法得到入射信号与x轴和z轴正方向夹角的估计值;最终基于虚拟信源功率的唯一性,通过构建相关代价函数实现各轴夹角估计值的匹配,进而根据各轴夹角与方位角和俯仰角的关系,得到相匹配的方位角和俯仰角估计值。本文方法提高了DOA估计精度,扩展了阵列孔径,提高了自由度,且通过求根多重信号分类方法,降低了计算复杂度。仿真实验结果表明,本文方法能够实现二维DOA估计与角度匹配,且相比于对比方法,本文方法能够估计更多的信号源,拥有更加优越的DOA估计性能。

基于高阶累计量Root-MUSIC法和Prony法的轧辊偏心谐波参数估计

针对轧辊偏心信号是混杂在各种随机干扰中含有多次谐波的复杂高频周期信号,以及FFT(Fast Fourier Transform)法对轧辊偏心信号分析的局限性,研究了一种基于四阶累积量的Root-MUSIC(Multiple Signal Classification)法和Prony法相结合的轧辊偏心信号估计新方法.利用基于四阶累积量的Root-MUSIC法准确估计出偏心谐波的频率及谐波的个数,同时由Root-MUSIC求得的根直接使用Prony方法估计出偏心信号的各次谐波幅值和相位.仿真结果和实验结果也验证了结合方法的可行性和有效性,在信噪比较低的情况下仍具有较高的频谱分辨率和估计精度,能准确地同时估计出偏心谐波的频率、幅值及相位,尤其在频率分辨率和抗噪声上具有FFT法无法比拟的优越性.

中压直流配电场景下混合型MMC过调制工况对运行稳定性的影响分析

混合型模块化多电平换流器(hybrid MMC)可通过过调制运行实现中压直流(MVDC)配电网的直流故障穿越.现有研究未充分分析过调制工况下混合型MMC的运行稳定性,无法满足中压直流配电网的运行需求.为此,本文通过与正常工况进行对比,分析了过调制工况对混合型MMC运行稳定性的影响.首先,在电气与控制部分统一的dq坐标系下,构建考虑直流调制比的混合型MMC小信号模型,并将其与详细电磁暂态(EMT)仿真结果对比,验证所建立模型的准确性;其次,对比正常及过调制工况下的根轨迹,进而从控制参数可行域的角度分析了过调制工况对系统运行稳定性的影响;然后,基于主导模态特征根的虚部计算系统失稳时的振荡频率,并将其与相同控制参数下电磁暂态仿真结果进行对比,验证上述稳定性分析结果的正确性;最后,基于参与因子法计算各状态变量对于主导模态的参与程度,从而揭示对系统稳定性影响较大的关键状态变量.理论分析及仿真结果表明,混合型MMC的内部模态会随着交流及直流电流控制器参数的增大而逐渐趋于不稳定;相较于正常工况,过调制工况下混合型MMC控制参数可行域扩大,小信号稳定性提高.

金雀根对高尿酸血症大鼠肾脏Toll样受体信号通路的影响

目的:探讨金雀根对高尿酸血症大鼠模型肾脏Toll样受体(TLRs)信号通路的调控作用。方法:将60只SD大鼠预留10只作为对照组,剩余50只采用灌胃氧嗪酸钾(1.5 g/kg)与腺嘌呤(0.1 g/kg)造模,造模成功后随机分为模型组、别嘌醇组、金雀根高剂量组、金雀根中剂量组、金雀根低剂量组,每组10只。金雀根高剂量组、金雀根中剂量组、金雀根低剂量组分别灌胃金雀根水煎液(5.4 g/kg、2.7 g/kg、1.35 g/kg),别嘌醇组灌胃别嘌醇(50 mg/kg),对照组、模型组分别灌胃生理盐水(10 mL/kg),连续灌胃14 d。治疗结束后采集血清用于肾功能检测;采集肾脏组织样本进行苏木精-伊红(HE)法染色观察;采用蛋白质免疫印迹法(WB)检测肾脏Toll样受体4(TLR4)、Toll样受体4(TLR2)、髓样分化因子88(MyD88)、白细胞介素1β(IL-1β)蛋白表达情况。结果:经金雀根治疗后,大鼠肾脏炎症细胞浸润程度较模型组显著改善;模型组大鼠血清尿酸、尿素氮、肌酐含量均较对照组显著升高(P<0.01),治疗后,别嘌醇组、金雀根高剂量组、金雀根中剂量组、金雀根低剂量组较模型组显著下降(P<0.01);模型组大鼠肾脏组织中TLR2、TLR4、MyD88、IL-1β蛋白表达较对照组显著升高(P<0.05),经药物干预后别嘌醇组、金雀根高剂量组、金雀根中剂量组、金雀根低剂量组蛋白表达较模型组显著下调(P<0.05)。结论:金雀根水煎液可通过下调高尿酸血症大鼠肾脏组织TLRs/MyD88/IL-1β通路关键靶点的表达,抑制组织炎症,进而发挥降尿酸作用。

基于自适应滤波时间常数的储能逆变器下垂控制

典型下垂控制下的储能逆变器在受扰时存在频率变化率过大问题,采用低通滤波器的下垂控制则存在振荡问题。为此,提出一种基于自适应滤波时间常数的储能逆变器下垂控制策略。首先推导建立了包含滤波器的下垂控制储能逆变器输出频率小信号模型,然后采用根轨迹法分析了滤波器时间常数对其稳定性的影响,进一步提出一种自适用滤波时间常数下垂控制策略,并给出了参数设计准则。最后,通过MATLAB/Simulink仿真对所提策略进行了验证。结果表明,所提方法可有效减小频率变化率并抑制振荡,从而降低分布式电源脱机的风险。

金雀根、黄芪及其配伍对糖尿病肾脏疾病大鼠JNK/SAPK信号通路的影响

目的探究金雀根、黄芪及其配伍对糖尿病肾脏疾病(DKD)模型大鼠肾脏保护作用及机制。方法将60只SD大鼠随机分为正常组、模型组、恩格列净组(10 mg/kg)、金雀根组(3.1 g/kg)、黄芪组(3.1 g/kg)、金雀根加黄芪组(6.2 g/kg),除正常组外,各组大鼠行左侧肾摘除手术并腹腔注射链脲佐菌素(STZ,35 mg/kg)建立DKD模型,各组分别给予相应药物灌胃8周。期间定期检测FBG、24 h尿微量蛋白(24 h U-mAlb)。给药8周后处死大鼠,检测Scr、BUN、Cystatin C水平,HE、PAS、Masson染色观察肾组织病理改变,免疫组织化学法检测巨噬细胞标志蛋白CD68、iNOS表达,Western blot法检测肾组织JNK/SAPK通路蛋白JNK、p-JNK和TNF-α、IL-1β、ICAM-1表达,ELISA法检测血清TNF-α、IL-1β、ICAM-1水平。结果与正常组比较,模型组大鼠FBG、24 h U-mAlb、BUN、Scr、Cystatin C水平均升高(P<0.01),肾组织出现病理损伤,肾组织和血清TNF-α、IL-1β、ICAM-1水平升高(P<0.01),肾组织JNK和p-JNK蛋白表达升高(P<0.01);与模型组比较,各给药组大鼠FBG、24 h U-mAlb、BUN、Scr、Cystatin C水平均降低(P<0.05,P<0.01),肾组织病理损伤减轻,肾组织和血清TNF-α、IL-1β、ICAM-1水平降低(P<0.01),肾组织JNK和p-JNK蛋白表达降低(P<0.01);金雀根组与黄芪组比较各指标均无明显变化(P>0.05);与金雀根组或黄芪组比较,金雀根加黄芪组各指标均有不同程度的改善(P<0.05,P<0.01)。结论金雀根、黄芪及其配伍可改善DKD大鼠肾功能,抑制M1型巨噬细胞,减少炎症因子分泌,减轻肾脏病理损伤,其机制可能与抑制JNK/SAPK信号通路激活有关,金雀根与黄芪配伍药效较好。

基于变分模态分解和SG滤波的二次谐波降噪

针对可调谐半导体激光器吸收光谱学,在测量低浓度气体过程中二次谐波存在的噪声问题,提出利用变分模态分解(VMD)和Savitzky-Golay滤波(SG滤波)相结合方法(简记为VMD-SG滤波)对含噪信号进行降噪。分析了VMD平衡参数的最优选取,利用所设框长调节因子P,选取SG滤波的最优框长。通过与其他几种降噪算法相比,VMD-SG滤波降噪算法在信噪比、均方根误差、波形恢复、二次谐波特征点误差方面均表现较优。在信噪比(SNR)为-7.8389 dB下该算法SNR提升量为22.047 dB,均方根误差为0.0154,与标准二次谐波相关系数为0.985。结果表明,基于VMD-SG滤波降噪算法的可调谐二极管吸收光谱复合降噪技术,在弱信号方面可以提高信号质量,有利于提高气体反演精度、系统检测灵敏度。

考虑铁路牵引负荷接入的电力系统小干扰稳定性分析

随着电气化铁路的飞速发展,电气化铁路牵引负荷已成为中国电力系统中最大的单体负荷,但其负荷特性对电力系统小干扰稳定性的影响尚不明晰。为此,首先建立电气化铁路牵引负荷等效数学模型,并基于此构建考虑牵引负荷接入的电力系统小干扰模型;其次利用特征值分析方法,分析牵引负荷机车速度、机车数量以及牵引负荷接入位置和占比对电力系统小干扰稳定性的影响;最后通过特征值根轨迹寻找同步发电机励磁参数的调节范围,并分析牵引负荷接入前、后和不同牵引负荷参数对电力系统励磁参数调节范围的影响。研究结果表明:牵引负荷接入后电力系统小干扰稳定性降低,系统励磁参数调节范围收缩,系统稳定裕度降低。