简介:摘要:采用高场工作模式,通过计算机模拟仿真,反复试验,研制成功一种高性能S波段小型化宽带带线环行器。本文介绍了环行器的设计思路和方法。
简介:摘要 : 针对温室番茄智能化管理需要,研究茎秆、叶片和绿果等 3类相近色目标的多波段图像融合方法,以凸显目标与背景亮度差异,提高目标视觉识别效率。根据其各自在 300~1000 nm范围的反射光谱特征差异,建立了针对其光谱数据分类的 Lasso正则化逻辑回归模型。基于模型的稀疏解特征,确定具有较大权值系数的 450、 600和 900 nm等 3个波段作为最优成像波段,在此基础上构建了温室番茄植株多波段图像在线采集系统。结合最优成像波段下相近色目标图像特征分析,提出了基于 NSGA-II的多波段图像加权融合方法,以增强特定目标与近色背景物体的图像亮度差异。最后通过现场试验对多波段图像融合效果进行评估。结果表明,分别以茎秆、叶片和绿果器官作为识别目标,通过多波段图像融合处理后,目标与背景之间的图像灰度差异绝对差值相应达到单波段图像的 2.02、 8.63和 7.89倍,即被识别目标与其他近色背景的亮度差异显著增强,且背景物的亮度波动得到抑制。本研究结果可以为农业环境近色目标视觉识别相关研究提供参考。
简介:[ 摘要 ] 采用膨胀法,结合金相法,测试了实验钢的临界转变点 Ac1 、 Ac3 及 Ms 点。测定了不同冷却温度下轧辊用钢 的膨胀曲线,得到了该材料的连续冷却转变曲线( CCT )。并根据温度对连续冷却转变过程中相转变的影响进行了探讨。
简介:摘要目的探讨肾小球补体C1q及C3c沉积与糖尿病肾病进展的相关性。方法纳入2011年1月至2019年7月在南京医科大学第一附属医院确诊的2型糖尿病肾病患者112例,其中男性83例(74.1%),年龄(51.22±11.12)岁,随访时间19.0(8.5,31.3)个月。根据肾小球C1q和C3c是否沉积分为四组:C1q无沉积C3c无沉积组(n=38)、C1q无沉积C3c沉积组(n=24)、C1q沉积C3c无沉积组(n=14)和C1q沉积C3c沉积组(n=36),检测24 h尿蛋白等临床指标并收集病理资料。采用Cox回归及Kaplan-Meier生存曲线评估肾C1q和C3c沉积对肾脏预后的影响。结果四组间24 h尿蛋白差异有统计学意义[分别为1.84(0.92,3.89),4.19(2.09,6.50)3.30(1.84,6.70),3.64(2.49,7.22)g/24 h,P<0.01],C1q沉积C3c沉积组24 h尿蛋白定量显著高于C1q无沉积C3c无沉积组(P<0.01)。Kaplan-Meier生存曲线结果提示,四组累积生存率差异有统计学意义(Log-rank χ²=8.785,P<0.05),C1q沉积C3c无沉积组累计生存率最低,预后最差。调整后的多因素Cox分析显示,肾小球C1q和C3c共沉积[风险比(HR)2.260,95%可信区间1.329~3.845,P<0.01]、肾小球C1q+C3c+IgM均沉积(HR=4.142,95%可信区间 1.071~16.021,P<0.05)是肾脏预后的独立危险因素。结论肾小球C1q及C3c沉积与糖尿病肾病患者蛋白尿、较差的肾功能和预后不良相关,且肾小球C1q和C3c共沉积是糖尿病肾病进展的独立危险因素。
简介:AbstractBackground:Aberrant activation of the complement system plays an important role in the pathogenesis and development of immunoglobulin A nephropathy (IgAN). The relationship between serum complement and the clinical-histopathological features and outcomes of IgAN is controversial. This retrospective study aimed to examine the relationship between the complement 3/4 (C3/C4) ratio and the clinicopathologic changes and prognosis of patients with IgAN.Methods:A total of 397 patients with primary IgAN from January 2007 to December 2012 at the Chinese People’s Liberation Army General Hospital were included in this study. The correlation test and Chi-square test or one-way analysis of variance test were performed to evaluate the relationship between the C3/C4 ratio and other clinical-pathological factors. Propensity score matching and a multivariate Cox regression model were used to calculate the risk factors of renal outcome.Results:The median follow-up period was 75 months. During the follow-up period, 62 patients (15.6%) developed into the end-stage renal disease (ESRD). The C3/C4 ratio at baseline was associated with the level of serum creatinine (SCr), 24 h urinary protein excretion (24 h Upre), global glomerular sclerosis, and tubulointerstitial lesion. The level of SCr and 24 h Upre and the degree of chronic kidney injury were statistically different among groups defined by different C3/C4 ratio levels. The survival rates of patients among groups with different C3/C4 ratio levels were different. After propensity score matching, eighty-eight pairs of patients were successfully matched, and the C3/C4 ratio was an influencing factor for the patients’ outcome (hazard ratio 0.587, 95% confidence interval 0.329-0.880). Patients with a C3/C4 ratio <3.6 had a poorer outcome compared with the others (P = 0.002).Conclusions:IgAN patients with decreased C3/C4 ratio displayed significantly more severe clinical symptoms and chronic renal injury than patients with higher ratios. A low C3/C4 ratio could be a risk factor for patients developing to ESRD.
简介:摘要: 火电厂在实际运行的过程中,最容易发生故障的类型就是电气设备故障,基于此,本篇文章主要对电气设备故障以及实际的故障处理方法进行深入的探究和分析。
简介:摘要目的分析1个诺里病家系的致病基因变异,确定其遗传学病因。方法对先证者核心家系4名成员的DNA样本进行全外显子组检测,筛选变异位点,确定致病基因。通过Sanger测序对核心家系及7名其他家系成员进行验证。结果全外显子组检测及Sanger测序结果显示先证者及另外3例男性患者的NDP基因均存在c.361C>T(p.Arg121Trp)半合子错义变异,先证者母亲、外祖母和2个表妹均为c.361C>T杂合变异携带者,正常表型男性家系成员均未检测到该变异,符合X连锁隐性遗传病的特点。结论NDP基因c.361C>T错义变异是该诺里病家系的遗传学病因。
简介:AbstractBackground:Developing effective spinal cord repair strategies for spinal cord injury (SCI) is of great importance. Emerging evidence suggests that microRNAs (miRNAs) are closely linked to SCI recovery. This study aimed to investigate the function of miR-34c in the neuronal recovery in rats with SCI.Methods:A rat model with SCI was established. Differentially expressed miRNAs were identified by a microarray analysis. MiR-34c expression in rats was measured by reverse transcription quantitative polymerase chain reaction. Altered expression of miR-34c or C-X-C motif ligand 14 (CXCL14) was introduced in SCI rats to measure their roles in neuronal recovery. Western blot analysis was performed to determine the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription-3 (STAT3). Neuronal apoptosis in rat spinal cord tissues was detected. The concentrations of SCI recovery-related proteins thyrotropin releasing hormone (TRH), prostacyclin (PGI2), and ganglioside (GM) were evaluated by enzyme-linked immunosorbent assay. Data were analyzed using a t-test with a one-way or two-way analysis of variance.Results:Rats with SCI presented decreased grip strength (112.03 ± 10.64 vs. 17.32 ± 1.49 g, P < 0.01), decreased miR-34c expression (7 days: 3.78 ± 0.44 vs. 0.95 ± 0.10, P < 0.05), and increased CXCL14 expression (7 days: 0.61 ± 0.06 vs. 2.91 ± 0.27, P < 0.01). MiR-34c was found to directly bind to CXCL14. Overexpression of miR-34c increased grip strength (11.23 ± 1.08 vs. 31.26 ± 2.99 g, P < 0.01) and reduced neuronal apoptosis in spinal cord tissues (53.61% ± 6.07% vs. 24.59% ± 3.32%, P < 0.01), and silencing of CXCL14 also increased the grip strength (12.76 ± 1.13 vs. 29.77 ± 2.75 g, P < 0.01) and reduced apoptosis in spinal cord tissues (55.74% ± 6.24% vs. 26.75% ± 2.84%, P < 0.01). In addition, miR-34c upregulation or CXCL14 downregulation increased the concentrations of TRH, PGI2, and GM, and reduced phosphorylation of JAK2 and STAT3 in rats with SCI (all P < 0.01).Conclusion:The study provided evidence that miR-34c could promote neuronal recovery in rats with SCI through inhibiting CXCL14 expression and inactivating the JAK2/STAT3 pathway. This study may offer new insights into SCI treatment.
简介:摘要:随着互联网时代的到来网络技术应用到人们生活的方方面面以及人民消费水平的提升,人们对网络购物的需求愈加强烈,轻松便捷的网络购物已经成为人们日常生活的一部分。网购已成了家喻户晓的新风尚,根据资料显示截至到2019年我国网民规模达到8.29亿,这庞大的人口基数为电子商务打好了环境,同时5g时代的到来将会进一步改善电子商务的环境,给电子商务带来蓬勃的发展机会。自从1995年电子商务之父-贝佐斯创造了网上书城亚马逊,电子商务平台迅速发展,有售卖二手产品的Ebay、有外贸服务的阿里巴巴、甚至有旅游电子商务的携程,各式各样的商业模式B2C、C2C、B2B也因此应运而生。根据中国电子商务研究中心报告,早在2015年中国网络零售模式B2C占比已超过了C2C,B2C模式可以说是比较典型的电子商务模式。唯品会是一家特殊的B2C电子商务平台,它的发展具有特殊性,从最开始的亏损,转变策略到之后的短短数年时间迅速上市,截至2017年唯品会的盈利记录都是遥遥领先,因此分析唯品会对其他电商平台发展具有一定的借鉴意义。本文以唯品会为研究案例,对其商业模式进行分析,最后提出相应的发展建议。