NHR

NHR
  • 文章类型: Journal Article
    尽管有超过50万种以植物为食的昆虫,我们的星球仍然是绿色的。事实上,对食草动物的易感性是个例外,因为植物对大多数昆虫物种都有抗性。这种现象被称为非宿主抗性(NHR),植物物种的每个个体都对害虫或病原体的所有变体具有抗性。虽然NHR代表了植物免疫系统最常见和持久的结果,这种植物防御的几个方面仍然难以捉摸,特别是在植物-昆虫相互作用中。在这次审查中,我们阐明了植物-昆虫相互作用中NHR的概念。我们强调,NHR是一种现象,是由于有效的植物防御为大多数昆虫草食动物提供抗毁性而引起的。这强调了NHR是界定地球上植物-昆虫相互作用范围的主要生态特征之一。我们进一步强调了已知参与针对昆虫的NHR的植物免疫系统的性状和分子成分。最后,我们讨论了如何利用NHR作为开发抗虫害作物的工具。鉴于昆虫对全球粮食安全构成重大威胁,植物NHR研究是一个至关重要的焦点,具有确保全球粮食安全的巨大潜力。
    Despite the existence of over half million species of plant-eating insects, our planet remains predominantly green. In fact, susceptibility to herbivory is the exception, as plants are resistant to most insect species. This phenomenon is known as nonhost resistance (NHR), where every individual of a plant species is resistant to all variants of a pest or pathogen. While NHR represents the most common and durable outcome of the plant immune system, several aspects of this type of plant defence remains elusive, particularly in plant-insect interactions. In this review, we clarify the concepts of NHR in plant-insect interaction. We emphasize that NHR is a phenomenon arising as a consequence of effective plant defences providing invulnerability to most insect herbivores. This underscores that NHR is one of the main ecological features delimiting the range of plant-insect interactions on Earth. We further highlight the traits and molecular components of the plant immune system known to participate in NHR against insects. Finally, we discuss how NHR can be leveraged as a tool to develop pest resilient crops. Given the significant threat insects pose to global food security, research in plant NHR represents a crucial focal point with immense potential for ensuring food security worldwide.
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  • 文章类型: Journal Article
    背景:非酒精性脂肪性肝病(NAFLD)是一种全球疾病,估计影响世界人口的三分之一。NAFLD是代谢综合征的肝脏表现。近年来,配方已经使用血液学实验室参数,据报道,它与肝脏的炎症和纤维化有关。在这项研究中,我们旨在通过超声成像评估诊断为NAFLD的患者的中性粒细胞与高密度脂蛋白(HDL)胆固醇(HDL-C)比率(NHR),这是文献中首次.
    方法:本研究是通过招募18至65岁的男性和女性来进行的。在所有病例中,超声检查均用作肝骨病的诊断方法。从患者中采集静脉血样进行血液学和生化测量。
    结果:研究人群包括155名患者,其中脂肪肝患者115例,对照组40例。在1级脂肪肝患者中,NHR被确定为99.6±56.8,2级组114.98±39.2,3级组122.9±51.1,对照组86.17±35.2。在分析中,与对照组相比,2级和3级脂肪肝患者的NHR具有统计学意义(分别为p=0.03和0.01)。然而,1级脂肪肝患者与对照组之间无统计学差异(p=0.53)。
    结论:我们发现NAFLD患者的NHR较高。NHR是一个廉价且易于访问的参数。NAFLD患者中FIB-4的NHR升高可能是肝脏炎症或纤维化的标志物。
    BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a global disease estimated to affect one-third of the world\'s population. NAFLD is the hepatic manifestation of metabolic syndrome. In recent years, formulations have been made using haematological laboratory parameters, and it has been reported to be associated with inflammation and fibrosis in the liver. In this study, we aimed to evaluate the neutrophil to high-density lipoprotein (HDL) cholesterol (HDL-C) ratio (NHR) in patients diagnosed with NAFLD by ultrasonographic imaging for the first time in the literature.
    METHODS: The study was carried out by recruiting men and women between the ages of 18 and 65 years who applied to the check-up outpatient clinic of our hospital. Ultrasonography was used as the diagnostic method for hepatosteatosis in all cases. Venous blood samples were taken from the patients for haematological and biochemical measurements.
    RESULTS: The study population consisted of 155 patients, 115 of whom were fatty liver patients and 40 were controls. NHR was determined as 99.6 ± 56.8 in those with grade 1 fatty liver, 114.98 ± 39.2 in those with grade 2, 122.9 ± 51.1 in those with grade 3, and 86.17 ± 35.2 in the control group. In the analysis, NHR was statistically significantly higher in grade 2 and 3 fatty liver patients compared with the control group (p = 0.03 and 0.01, respectively). However, there was no statistical difference between grade 1 fatty liver patients and the control group (p = 0.53).
    CONCLUSIONS: We found higher NHR in patients with NAFLD. NHR is a cheap and easy to access parameter. An elevated NHR with FIB-4 in patients with NAFLD may be a marker of liver inflammation or fibrosis.
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  • 文章类型: Journal Article
    背景:根据欧洲指南,对于年龄≥75岁的重度主动脉瓣狭窄患者,可选择经导管主动脉瓣置入术(TAVI)治疗.在荷兰,医疗保健提供者和国家医疗保健研究所之间就TAVI的报销进行了辩论,这导致了一份适应症文件,该文件定义了符合报销条件的TAVI患者。本文件自2021年1月1日起生效。
    方法:我们从荷兰心脏注册中心提取了2018年至2021年在荷兰接受生物外科主动脉瓣置换术(SAVR)或TAVI的患者的数据。我们比较了随后年份和年龄组的基线特征和适应症文件中的变量。我们还分析了年度SAVR/TAVI比率。
    结果:在2018-2021年,接受SAVR或TAVI治疗的患者总数保持不变。接受TAVI治疗的患者的基线特征多年来没有差异。从2018年到2019年,SAVR/TAVI比率向TAVI的更高比例转变。从2019年到2020年,TAVI百分比保持不变。自指示文件实施以来(2021年),也未发现SAVR/TAVI比值的变化.
    结论:自2021年实施AVR国家适应症文件以来,在荷兰,SAVR与TAVI相比没有出现重大影响。
    BACKGROUND: Based on European guidelines, transcatheter aortic valve implementation (TAVI) could be the therapy of choice in patients with severe aortic stenosis aged ≥ 75 years. In the Netherlands, there has been a debate between healthcare providers and the National Health Care Institute regarding reimbursement for TAVI, which resulted in an indication document that defines TAVI patients who are eligible for reimbursement. This document has been effective since 1 January 2021.
    METHODS: We extracted data from the Netherlands Heart Registry for patients who underwent biological surgical aortic valve replacement (SAVR) or TAVI in the Netherlands from 2018 through 2021. We compared baseline characteristics and variables from the indication document for the subsequent years and age groups. We also analysed the annual SAVR/TAVI ratio.
    RESULTS: The total number of patients treated with SAVR or TAVI was constant in 2018-2021. Baseline characteristics of patients treated with TAVI did not differ throughout the years. The SAVR/TAVI ratio shifted towards a higher percentage of TAVI from 2018 to 2019. From 2019 to 2020, the TAVI percentage was constant. Since the implementation of the indication document (in 2021), a change in the SAVR/TAVI ratio was not found either.
    CONCLUSIONS: Since the implementation of the national indication document for AVR in 2021, no major effect was seen for the SAVR versus TAVI landscape in the Netherlands.
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  • 文章类型: Journal Article
    多发性骨髓瘤(MM)是一种恶性疾病,其特征在于骨髓中B细胞衍生的浆细胞的单克隆增殖。它是成人第二常见的血液恶性肿瘤。这项回顾性研究的目的是评估MM中血液学参数的诊断和预后价值。
    比较了151例新诊断的MM患者和153例健康对照者的NLR/ALB比值(NAR)和NLR/HDL-C比值(NHR)的差异。根据从ROC曲线获得的NAR和NHR截止值,MM患者分为低组和高组。比较两组患者血液学指标和生存时间的差异。采用Cox比例风险回归模型进行独立预后分析。
    MM组的NAR和NHR值均显著高于对照组(P<0.001)。较高的NAR水平与较低的白蛋白(ALB)显着相关,较高的β2微球蛋白(β2-MG),较高的肌酐(Crea),ISS分期较高(均P<0.05)。高NHR组与年龄显著相关,β2-MG与ISS分期(均P<0.05)。在高NAR或NHR组中,OS和DFS明显缩短,预后差(P<0.05)。多因素分析显示,ISS分期和NAR是MM患者OS的独立预后指标,而ALB,PLT和NAR是影响DFS的独立预后因素。
    NAR和NHR价格低廉,随时可用的MM诊断指标,NAR是MM的独立预后因素。
    UNASSIGNED: Multiple myeloma (MM) is a malignant disease characterized by a single clonal proliferation of B cell-derived plasma cells in the bone marrow. It is the second most common haematologic malignancy in adults. The objective of this retrospective study is to evaluate the diagnostic and prognostic value of haematologic parameters in MM.
    UNASSIGNED: The difference of NLR/ALB ratio (NAR) and NLR/HDL-C ratio (NHR) between the 151 newly diagnosed MM patients and 153 healthy controls was compared. According to NAR and NHR cutoff values obtained from the ROC curve, MM patients were divided into low group and high group. The differences in hematological parameters and survival time between the two groups were compared. Independent prognostic analysis was performed using Cox proportional hazard regression model.
    UNASSIGNED: The NAR and NHR values in MM group were significantly higher than those in control group (P < 0.001). Higher NAR levels were significantly associated with lower albumin (ALB), higher β2 microglobulin(β2-MG), higher creatinine (Crea), and highe ISS stage (All P<0.05). High NHR group was significantly correlated with age , β2-MG and ISS stage (All P<0.05). In high NAR or NHR groups, OS and DFS was significantly shortened and the prognosis was poor (P < 0.05). Multivariate analysis showed that PLT, ISS stage and NAR were independent prognostic indicators of OS in MM patients, while ALB, PLT and NAR were independent prognostic factors of DFS.
    UNASSIGNED: NAR and NHR are inexpensive, readily available diagnostic indicators for MM, and NAR is an independent prognostic factor for MM.
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  • 文章类型: Journal Article
    缺血性卒中(IS)在病因和病理生理学方面表现出明显的异质性。最近的几项研究强调了炎症在IS发作和进展中的重要性。白细胞亚型,如中性粒细胞和单核细胞,以各种方式参与炎症反应。另一方面,高密度脂蛋白(HDL)具有显著的抗炎和抗氧化作用。因此,新的炎症血液生物标志物已经出现,例如中性粒细胞与HDL比率(NHR)和单核细胞与HDL比率(MHR)。对两个数据库(MEDLINE和Scopus)进行文献研究,以确定2012年1月1日至2022年11月30日发表的所有相关研究,涉及NHR和MHR作为IS预后的生物标志物。仅包括以英语发表的全文文章。已经追踪了13篇文章,并包括在本评论中。我们的发现强调了NHR和MHR作为新型卒中预后生物标志物的实用性,广泛应用,以及其中的计算,加上他们便宜的成本,使其临床应用前景极为广阔。
    Ischemic stroke (IS) exhibits significant heterogeneity in terms of etiology and pathophysiology. Several recent studies highlight the significance of inflammation in the onset and progression of IS. White blood cell subtypes, such as neutrophils and monocytes, participate in the inflammatory response in various ways. On the other hand, high-density lipoproteins (HDL) exhibit substantial anti-inflammatory and antioxidant actions. Consequently, novel inflammatory blood biomarkers have emerged, such as neutrophil to HDL ratio (NHR) and monocyte to HDL ratio (MHR). Literature research of two databases (MEDLINE and Scopus) was conducted to identify all relevant studies published between 1 January 2012 and 30 November 2022 dealing with NHR and MHR as biomarkers for IS prognosis. Only full-text articles published in the English language were included. Thirteen articles have been traced and are included in the present review. Our findings highlight the utility of NHR and MHR as novel stroke prognostic biomarkers, the widespread application, and the calculation of which, along with their inexpensive cost, make their clinical application extremely promising.
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  • 文章类型: Journal Article
    背景:炎症指标与动脉粥样硬化的关系以及血脂指标与动脉粥样硬化的关系已被广泛研究。但中性粒细胞与高密度脂蛋白胆固醇比值(NHR)与动脉粥样硬化之间的关系直到本研究才被研究.
    方法:对于这项横断面研究,我们连续收集2012年1月至2017年12月河北医科大学第二医院健康体检人群的数据(N=1978).收集的数据包括临床数据,血液学指标,臂踝脉搏波传导速度(Ba-PWV)。动脉粥样硬化定义为Ba-PWV≥1400cm/s。通过单因素回归分析探讨NHR与动脉粥样硬化的关系,多元回归分析,平滑函数分析,并分析了阈值饱和效应。
    结果:在1978年的参与者中,平均年龄是54岁,1189名参与者(60.11%)为男性,1103例(55.76%)有动脉粥样硬化病史。单因素分析显示NHR与动脉粥样硬化呈正相关[比值比(OR)=1.19,95%置信区间(CI):1.11-1.27,P<0.01],在校正混杂因素的多变量分析中,这种正相关仍然显着(OR=1.14,95%CI:1.06-1.24,P<0.01)。广义加性模型结果表明,NHR与动脉粥样硬化之间存在饱和效应的非线性关系,阈值为3.32。值≤3.32时,NHR与动脉粥样硬化呈正相关,但值>3.32时,相关性无统计学意义.
    结论:在健康检查人群中,NHR与动脉粥样硬化之间观察到具有一定饱和效应的非线性关系。
    BACKGROUND: The relationships between inflammatory indexes and atherosclerosis as well as those between blood lipid indexes and atherosclerosis have been widely studied, but the relationship between the neutrophil to high-density lipoprotein cholesterol ratio (NHR) and atherosclerosis had not been investigated until the present study.
    METHODS: For this cross-sectional study, we continuously collected data from a health examination population in the Second Hospital of Hebei Medical University from January 2012 to December 2017 (N = 1978). The collected data included clinical data, hematological indexes, and brachial-ankle pulse wave velocity (Ba-PWV). Atherosclerosis was defined as Ba-PWV ≥ 1400 cm/s. The relationship between the NHR and atherosclerosis was explored via univariate regression analysis, multivariate regression analysis, smoothing function analysis, and analysis of a threshold saturation effect.
    RESULTS: Among 1978 participants, the mean age was 54 years, 1189 participants (60.11%) were male, and 1103 (55.76%) had a history of atherosclerosis. Univariate analysis showed a positive association between the NHR and atherosclerosis [odds ratio (OR) = 1.19, 95% confidence interval (CI): 1.11-1.27, P < 0.01], and this positive association remained significant on multivariate analyses with adjustments for confounding factors (OR = 1.14, 95% CI: 1.06-1.24, P < 0.01). Generalized additive model results revealed a non-linear relationship with a saturation effect between the NHR and atherosclerosis, with a threshold at 3.32. At values ≤ 3.32, the NHR was positively associated with atherosclerosis, but the association was not statistically significant for values > 3.32.
    CONCLUSIONS: A nonlinear relationship with a certain saturation effect was observed between the NHR and atherosclerosis in a health examination population.
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  • 文章类型: Journal Article
    本研究旨在探讨单核细胞与高密度脂蛋白胆固醇比值(MHR)的预测价值,中性粒细胞与高密度脂蛋白胆固醇比率(NHR),C反应蛋白与淋巴细胞比率(CLR),和C反应蛋白与白蛋白比值(CAR)治疗2型糖尿病(T2DM)患者的活动性肺结核(APTB)。
    共有991名活动性肺结核(APTB)患者(201名T2DM)在结核病科住院,武汉市金银滩医院,同济医学院,包括华中科技大学。收集血常规检查指标和生化指标,计算MHR,NHR,CLR,和汽车。皮尔逊相关分析,单因素Logistic回归分析,受试者工作特征(ROC)曲线分析评估MHR的预测价值,NHR,CLR,和CAR用于APTB-T2DM患者。
    MHR的水平,NHR,CLR,APTB-T2DM患者的CAR明显高于APTB-非T2DM患者(P<0.05)。此外,MHR,NHR,CLR,在整个研究人群中,CAR与空腹血糖呈正相关。然而,在APTB-T2DM患者中,MHR,NHR,和CAR与空腹血糖无关,仅CLR与空腹血糖呈正相关。预测APTB-T2DM患者MHR的曲线下面积(AUC),NHR,CLR,CAR分别为0.632、0.72、0.715和0.713。Further,单因素Logistic回归分析表明,MHR越高,NHR,CLR,CAR是APTB-T2DM的独立危险因素(P<0.01)。MHR,NHR,CLR,和CAR四分位数用于将APTB患者分为四组进行进一步分析。APTB个体中T2DM的患病率明显高于MHR,NHR,CLR,CAR值升高(P<0.05)。
    MHR,NHR,CLR,和CAR是简单可行的炎症参数,可用于评估APTB中的T2DM。APTB患者诊断为T2DM的可能性越大,MHR越高,NHRCLR,和CAR值。因此,APTB检查中应更多关注该指标。
    UNASSIGNED: This study was to explore the predictive value of monocyte to high-density lipoprotein cholesterol ratio (MHR), neutrophils to high-density lipoprotein cholesterol ratio (NHR), C-reactive protein-to-lymphocyte ratio (CLR), and C-reactive protein-to-albumin ratio (CAR) for type 2 diabetes mellitus (T2DM) in patients with active pulmonary tuberculosis (APTB).
    UNASSIGNED: A total of 991 active pulmonary tuberculosis (APTB) patients (201 with T2DM) were hospitalized in the Department of Tuberculosis, Wuhan Jinyintan Hospital, Tongji Medical College, Huazhong University of Science and Technology were included. The routine blood examination indicators and biochemical parameters were collected to calculate MHR, NHR, CLR, and CAR. The Pearson correlation analysis, Univariate Logistic regression analysis, and receiver operating characteristic (ROC) curve analysis were performed to assess the predictive value of MHR, NHR, CLR, and CAR for APTB-T2DM patients.
    UNASSIGNED: The levels of MHR, NHR, CLR, and CAR in the APTB-T2DM patients were significantly higher than in the APTB-no T2DM patients (P < 0.05). Additionally, the MHR, NHR, CLR, and CAR have a positive correlation with fasting blood glucose in the whole study population. However, in the APTB-T2DM patients, MHR, NHR, and CAR were not correlated with fasting blood glucose, and only CLR was positively correlated with fasting blood glucose. The area under curve (AUC) predicting APTB-T2DM patients of the MHR, NHR, CLR, and CAR was 0.632, 0.72, 0.715, and 0.713, respectively. Further, univariate logistic regression analyses showed that the higher MHR, NHR, CLR, and CAR were independent risk factors for APTB-T2DM (P < 0.01). The MHR, NHR, CLR, and CAR quartiles were used to divide the APTB patients into four groups for further analysis. The prevalence of T2DM was significantly higher in APTB individuals as MHR, NHR, CLR, and CAR values increased (P < 0.05).
    UNASSIGNED: MHR, NHR, CLR, and CAR are simple and practicable inflammatory parameters that could be used for assessing T2DM in APTB. APTB patients have a greater possibility to be diagnosed with T2DM with the higher MHR, NHR CLR, and CAR values. Therefore, more attention should be given to the indicator in the examination of APTB.
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  • 文章类型: Journal Article
    Nuclear receptors (NRs) are responsible for the regulation of diverse developmental and physiological systems in metazoans. NR actions can be the result of genomic and non-genomic mechanisms depending on whether they act inside or outside of the nucleus respectively. While the actions of both mechanisms have been shown to be crucial to NR functions, non-genomic actions are considered less frequently than genomic actions. Furthermore, hypotheses on the origin and evolution of non-genomic NR signaling pathways are rarely discussed in the literature. Here we summarize non-genomic NR signaling mechanisms in the context of NR protein family evolution and animal phyla. We find that NRs across groups and phyla act via calcium flux as well as protein phosphorylation cascades (MAPK/PI3K/PKC). We hypothesize and discuss a possible synapomorphy of NRs in the NR1 and NR3 families, including the thyroid hormone receptor, vitamin D receptor, ecdysone receptor, retinoic acid receptor, steroid receptors, and others. In conclusion, we propose that the advent of non-genomic NR signaling may have been a driving force behind the expansion of NR diversity in Cnidarians, Placozoans, and Bilaterians.
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  • 文章类型: Journal Article
    背景:冠状动脉疾病(CAD),作为最常见的死因,主要是由动脉粥样硬化引起的。由于炎症在动脉粥样硬化过程中的作用,在本研究中,单核细胞与HDL-C比值(MHR)与冠心病严重程度的关系,血小板与HDL-C比值(PHR),中性粒细胞与HDL-C比值(NHR),和IL-25进行了调查。方法:在这项横断面研究中,研究了在哈马丹Farshchian心脏中心接受血管造影的64例诊断为冠状动脉疾病的患者。对于每个病人来说,单核细胞的计数,中性粒细胞,血小板,和HDL-C,从他们的血液和血清样品中测量IL-25。此外,人口统计信息,比如年龄,性别,糖尿病,吸烟,高血压病史,是使用清单收集的。数据使用频率来描述,%,意思是,和标准偏差。统计学分析采用独立t检验,Mann-Whitney,Wilcoxon,和Spearman等级相关检验,和SPSS25.0版SPSSInc)的多元线性回归。P<0.05被认为是显著的。结果:本研究结果显示,IL-25和MHR指数与冠状动脉病变及Gensini评分有显著相关性(P<0.001)。PHR指数与冠状动脉疾病有关。此外,定性变量,比如高血压病史,吸烟史,和性别,与冠状动脉疾病的严重程度有显著关联(P<.05)。结论:在检查的炎症标志物中,IL-25和MHR是评估冠状动脉疾病严重程度的更强标志物。简单和可用的IL-25和MHR测量可能能够,以及常见的危险因素和血脂,预测治疗中心血管闭塞的数量,作为血管造影的替代方法,以及筛查易患心血管疾病的高危患者。
    Background: Coronary artery disease (CAD), as a most common cause of death, is mainly caused by atherosclerosis. Due to the role of inflammation in the process of atherosclerosis, in the present study, the relationship between the severity of coronary artery disease and inflammatory factors of monocyte to HDL-C ratio (MHR), platelet-to-HDL-C ratio (PHR), neutrophil to HDL-C ratio (NHR), and IL-25 was investigated. Methods: In this cross-sectional study, 64 patients with diagnosis of coronary artery disease who were undergoing angiography in Farshchian heart center in Hamadan were studied. For each patient, the count of monocytes, neutrophils, platelet, and HDL-C, and IL-25 were measured from their blood and serum samples. Also, demographic information, such as age, gender, diabetes, smoking, and history of hypertension, was collected using a checklist. Data were described using frequency, percent, mean, and standard deviation. Statistical analysis was performed using independent t test, Mann-Whitney, Wilcoxon, and Spearman rank correlation tests, and multiple linear regression by SPSS version 25.0 SPSS Inc). P <.05 was considered as significant. Results: The results of this study showed that IL-25 and MHR index has a significant correlation with coronary artery disease and Gensini score (P ˂.001). The PHR index was associated with coronary artery disease. Also, qualitative variables, such as history of hypertension, history of smoking, and gender, have a significant association with the severity of coronary artery disease (P <.05). Conclusion: Among the inflammatory markers examined, IL-25 and MHR are stronger markers for assessing the severity of coronary artery disease. Simple and available IL-25 and MHR measurements may be able to, along with common risk factors and lipid profiles, predict the amount of vascular occlusion in treatment centers as an alternative of angiography as well as screening high risk patients prone to cardiovascular disease.
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  • 文章类型: Journal Article
    为了解北京冬季精细气溶胶污染特征,我们进行了大气痕量氨(NH3)的连续测量,2015年2月13日至3月17日,北京某城区PM2.5和PM2.5中的无机离子。在整个过程中,NH3的小时平均浓度为15.4±17.5ppb。NH3浓度与PM2.5中的NH4浓度密切相关,表明NH3对NH4形成的主要前体作用。昼夜曲线表明早高峰时段NH3浓度增加,这可能是由于车辆排放。平均铵转化率(NHR)为0.26,下午最高值为0.32。NHR升高,硝酸盐氧化比(NOR),和NH4+与下午O3水平的显著增加相吻合,表明NH4NO3通过光化学反应在白天大量形成。此外,较高的NHR值发生在较高的相对湿度(RH>60%)和较低的温度(0-10°C)下。NHR在夜间增加,与RH相关性良好,表明非均相反应对气体-颗粒分配的主导作用。硫酸盐氧化率(SOR)和NOR与RH呈正相关,这表明SO2向SO42-和NO2向NO3-的转化对RH的变化敏感。在RH>60%时SO42-浓度的持续增加表明RH对SO42-形成的影响高于对NO3-形成的影响。作为NH4+的唯一前体,NH3通过均相气相反应显着增强了白天NH4NO3的形成,并通过均相和非均相反应促进了硫酸盐的形成。此外,反向轨迹结果推断西南气团对北京大气NH3和NH4气溶胶变化的贡献很大。结果表明,北京冬季需要控制车辆排放,以减少NH3的高水平并减轻PM2.5污染。
    To understand the characteristics of winter fine aerosol pollution in Beijing, we conducted continuous measurements of the atmospheric trace gas ammonia (NH3), PM2.5, and inorganic ions in PM2.5 at an urban site in Beijing from February 13 to March 17, 2015. The hourly average concentration of NH3 throughout the campaign was 15.4 ± 17.5 ppb. NH3 concentrations correlated well with NH4+ in PM2.5, indicating the dominant precursor role of NH3 on NH4+ formation. The diurnal profile indicated an increase in NH3 concentrations during the morning rush hours, which was likely due to vehicle emissions. The mean ammonium conversion ratio (NHR) was 0.26, with the highest value of 0.32 in the afternoon. Elevated NHR, nitrate oxidation ratio (NOR), and NH4+ coincided with the significant increase in O3 levels in the afternoon, indicating the large daytime formation of NH4NO3 via photochemical reactions. Moreover, higher NHR values occurred under higher relative humidity (RH >60%) and lower temperature (0-10 °C). NHR increased during the nighttime and correlated well with RH, indicating the dominant role of heterogeneous reactions on gas-particle partitioning. The sulfate oxidation ratio (SOR) and NOR showed positive correlations with RH, which suggests that the conversions of SO2 to SO42- and NO2 to NO3- were sensitive to changes in RH. The sustained increase in SO42- concentrations at RH >60% suggests that RH had a higher influence on SO42- formation than on NO3- formation. As the sole precursor of NH4+, NH3 significantly enhanced daytime NH4NO3 formation via homogeneous gas-phase reactions and also promoted sulfate formation via both homogeneous and heterogeneous reactions. Moreover, the back trajectory results inferred a high contribution of southwestern air masses to atmospheric NH3 and NH4+ aerosol variations in Beijing. The result suggests the need for controlling the vehicle emissions to reduce the high levels of NH3 and alleviate PM2.5 pollution in winter in Beijing.
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