1.Fibroblast Growth Factors in Parkinson’s Disease: Multi-target Neuroprotective Mechanisms Involving Neuroinflammation, Cellular Stress, and Ferroptosis
Hui WANG ; Zi-Gui ZHOU ; Teng-Teng HAN ; Chang-Zhi YANG ; Xue-Wen TIAN
Progress in Biochemistry and Biophysics 2026;53(4):855-874
Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the substantia nigra pars compacta and the pathological accumulation ofα‑synuclein. Although extensive progress has been made in elucidating its pathogenesis, current therapeutic approaches remain largely symptomatic, and effective disease-modifying treatments are still unavailable. Increasing evidence indicates that PD is driven by the interaction of multiple pathological processes, including neuroinflammation, iron homeostasis dysregulation and ferroptosis, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, oxidative stress, and impaired protein homeostasis, which together contribute to neuronal vulnerability and degeneration. Fibroblast growth factors (FGFs) comprise a family of 22 ligands that play important roles in neural development, stress responses, metabolic regulation, and the maintenance of nervous system homeostasis. Recent studies have shown that several FGF family members, such as FGF1, FGF2, FGF9, and FGF21, exert neuroprotective effects in cellular and animal models of PD. These effects include the regulation of inflammatory responses, oxidative stress, iron homeostasis, cellular stress adaptation, and neuronal survival. Compared with therapeutic strategies targeting a single pathogenic pathway, FGFs appear to influence multiple disease-related processes, suggesting their potential relevance to the complex pathophysiology of PD. Experimental evidence indicates that altered FGF signaling may contribute to dopaminergic neuron dysfunction through the coordinated regulation of several interconnected mechanisms. FGFs have been reported to modulate neuroinflammation by affecting the activation of microglia and astrocytes, thereby influencing the inflammatory environment in the central nervous system. In addition, FGFs are involved in the regulation of iron homeostasis and ferroptosis, partly through antioxidant signaling pathways associated with NRF2, SLC7A11, and GPX4. Moreover, FGFs can alleviate ER stress and mitochondrial dysfunction by activating intracellular signaling pathways such as PI3K/AKT, AMPK-PGC-1α, as well as SIRT1-dependent programs, which support cellular energy metabolism and redox balance. Recent advances in single-cell and spatial transcriptomic studies further suggest that FGF signaling is not limited to neuron-intrinsic mechanisms but also involves interactions among different glial cell types. Altered FGF ligand-receptor communication between astrocytes and oligodendrocytes has been observed in PD models and is associated with increased susceptibility of dopaminergic neurons to oxidative stress and ferroptosis. These findings indicate that the biological effects of FGFs are influenced by cell type and disease stage and may vary under different pathological conditions. In this review, we summarize recent progress in understanding the roles of FGF family members in PD, with a focus on their involvement in iron homeostasis dysregulation and ferroptosis, neuroinflammation, cellular stress responses, and neuronal protection and regeneration. By integrating current evidence, this review aims to provide a clearer understanding of how FGFs participate in PD pathogenesis and to offer a theoretical basis for future studies exploring their potential value in disease-modifying therapeutic strategies.
2.Three-dimensional Electrical Impedance Tomography for Monitoring Gastric Hemorrhage
Zi-Han ZHAO ; Bo SUN ; Jing-Shi HUANG ; Zhi-Wei LI ; Yang WU ; Nan LI ; Jia-Feng YAO ; Tong ZHAO
Progress in Biochemistry and Biophysics 2026;53(4):1062-1075
ObjectiveGastric hemorrhage is one of the most common and life-threatening emergencies of the upper digestive tract. Early identification and continuous monitoring are essential for reducing rebleeding rates and mortality, particularly within the critical early hours after onset. Although endoscopy and radiological imaging can accurately localize bleeding sites, these approaches are invasive, resource-intensive, and unsuitable for continuous bedside monitoring. Electrical impedance tomography (EIT), as a noninvasive and radiation-free functional imaging technique, offers real-time visualization of conductivity distribution and has the potential for detecting intragastric bleeding based on the electrical contrast between blood and surrounding gastric tissues. In this study, a three-dimensional gastric EIT (3D-gEIT) framework is proposed to achieve noninvasive, real-time, and dynamic monitoring of gastric hemorrhage, with emphasis on spatial localization and quantitative volume assessment. MethodsA three-dimensional upper-abdominal simulation model incorporating the stomach, gastric wall, gastric contents, and surrounding tissues was established. Three electrode configurations, namely the dual layer ring, the four layer staggered ring, and the opposed dual plane array, were designed and systematically compared to evaluate their influence on depth sensitivity and spatial resolution. Based on the Tikhonov-Noser hybrid regularization scheme, a region-clustering constraint was introduced to develop the TK-Noser-RCC algorithm. This approach aggregates spatially adjacent elements with similar conductivity variations, thereby enhancing structural continuity and suppressing isolated noise artifacts. To validate the proposed framework, an upper-abdominal physical phantom was constructed using agar to simulate background tissue conductivity. Hemispherical high-conductivity inclusions with volumes ranging from 10 ml to 50 ml were attached to the inner gastric wall to mimic localized bleeding under different gastric filling states. Boundary voltages were acquired under a 120 kHz excitation current and reconstructed using the TK-Noser-RCC algorithm. Furthermore, an in vivo animal experiment was performed using a porcine model with adult-scale abdominal dimensions. A total of 100 ml of autologous blood was injected incrementally into the stomach to simulate progressive gastric hemorrhage, and time-difference EIT reconstruction was conducted at each injection stage to assess the dynamic system response under physiological conditions. ResultsSimulation results demonstrated that the opposed dual-plane electrode array achieved superior depth sensitivity distribution and spatial resolution. For a 40 ml hemorrhage model, the average ICC and SSIM improved by 55.9% and 38.8% compared with the dual-layer ring configuration, and by 64.0% and 39.5% compared with the four-layer staggered configuration. The proposed region-clustering constraint significantly enhanced reconstruction stability. Under added Gaussian noise of 40 dB and 30 dB, ICC values remained approximately 0.85, indicating effective artifact suppression and preservation of boundary integrity. In physical phantom experiments, reconstructed hemorrhage volumes increased approximately linearly with the preset hemispherical volumes, and the reconstructed high-conductivity regions closely matched the actual bleeding locations. Both empty-stomach and full-stomach conditions were evaluated, demonstrating that the opposed dual-plane configuration maintained stable imaging performance across varying gastric contents. In the animal experiment, reconstructed low-impedance regions expanded progressively with increasing injected blood volume. The spatial localization of the hemorrhage remained stable throughout the procedure, and no significant artifacts were observed. Quantitative analysis showed that reconstructed volume and average conductivity variation exhibited an approximately linear growth trend with injected blood volume, confirming the sensitivity of the system to dynamic intragastric conductivity changes. ConclusionThe proposed 3D-gEIT framework enables quantitative reconstruction of gastric hemorrhage volume and spatial distribution with improved depth sensitivity, structural continuity, and noise robustness compared with conventional EIT approaches. By integrating optimized electrode configuration and a region-clustering-constrained reconstruction algorithm, the system provides stable dynamic monitoring under both controlled phantom conditions and in vivo physiological environments. This method offers a noninvasive, real-time, and low-cost imaging strategy for early diagnosis, postoperative monitoring, and bedside surveillance of gastric bleeding.
3.Anticonvulsant and neuroprotective effects of jujuboside B on acute epilepsy
Wanruo HAN ; Linyu ZHI ; Hongye Wang BENJAMIN ; Xu LIU
Chinese Journal of Clinical Medicine 2026;33(2):277-284
Objective To investigate the alleviating effect of jujuboside B (JuB) on acute epilepsy in mice and its protective effect on hippocampal neurons. Methods An in vitro epilepsy model was established by stimulating primary hippocampal neurons with cyclothiazide (CTZ). Spontaneous epileptiform discharge was recorded using patch clamp technique. An acute epilepsy model was induced in adult male C57BL/6 mice by intraperitoneal injecting pentylenetetrazol (PTZ) following pretreatment with JuB, and severity of epilepsy was recorded. Mice were euthanized and brain tissues were collected 24 hours after model establishment. The expression levels of mitoptosis related proteins in the hippocampus were detected by Western blotting. Neuronal damage in the hippocampal CA1 and CA3 regions was observed using pathological staining. Results JuB reduced the frequency of CTZ-induced epileptiform discharges (P<0.001). Pretreatment with 30 mg/kg and 50 mg/kg JuB decreased the maximal behavioral seizure score and prolonged the latency to Racine stage Ⅲ seizures in PTZ-induced epileptic mice (P<0.001). Compared with the PTZ group, JuB treatment downregulated Bax protein level (P<0.01) and upregulated Bcl-2 protein level (P<0.05) in acute epileptic mice. Furthermore, JuB protected neuronal viability in the hippocampal CA1 (P<0.05) and CA3 (P<0.01) regions, and ameliorated pathological morphological changes including cellular disarray, unclear boundaries, pyknosis, fragmentation, and dissolution. Conclusions JuB exhibits antiepileptic effects both in vivo and in vitro. It exerts potential antiepileptic effects by inhibiting mitoptosis and attenuating neuronal damage in the hippocampus in an acute epilepsy model.
4.Statistical analysis of vector monitoring in port areas of Shandong Province from 2017 to 2023
Huan-mei HAN ; Tao ZHANG ; Zhi-ping SU ; Rong-jun YAN ; Wei HUANG ; Wen-wen ZHANG
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):121-127
Objective To provide a scientific basis for vector prevention and control in port areas, vector monitoring has been conducted continuously to characterize the composition, density, and seasonal fluctuations of vectors across 21 port-areas of Shandong province from 2017 to 2023. Methods In accordance with the Regional Vector Monitoring Plan for Frontier Ports, vector surveillance of mosquitoes, flies, cockroaches, rodents, and other disease vectors was performed. Data were analyzed to describe vector community composition and identify seasonal fluctuations. Results A total of 601 rodents belonging to 1 family, 4 genera, and 4 species were captured. Three dominant rodent species inhabit port areas. In addition, 88 104 mosquitoes were captured and classified into 3 subfamilies, 4 genera, and 12 species; 38 959 flies were trapped and classified into 8 families,31 genera, and 51 species, including 9 dominant fly species in port-areas; and 54 672 captured cockroaches were classified into 2 families,4 genera, and 4 species, with Blattella germanica as the dominant species. Conclusions Significant vector community changes(P<0.005)have been identified after the epidemic. To improve the pertinence and efficacy of port health quarantine work, continuous and strong attention should be paid to vector compositions and population densities at Shandong ports.
5.The Dual Role and Clinical Potential of Core Fucosylation in Liver Diseases
Zi-Han LEI ; Hui-Min XU ; De-Zhi ZHAO ; Yong-Hong GUO ; Hao-Qi DU
Progress in Biochemistry and Biophysics 2026;53(8):2161-2178
Core fucosylation, catalyzed exclusively by fucosyltransferase 8 (FUT8), is an evolutionarily conserved post-translational modification that has emerged as a central regulatory hub linking liver homeostasis, chronic disease progression, and malignant transformation. Liver diseases, particularly hepatocellular carcinoma, remain a leading global health burden characterized by late diagnosis, limited therapeutic options, and poor overall survival. While aberrant glycosylation is now recognized as a hallmark of cancer and inflammatory disorders, existing research on FUT8-mediated core fucosylation in liver diseases remains fragmented: the dynamic functional switch of FUT8 from a homeostatic regulator to a pathological driver across the full disease continuum has not been systematically delineated, and the integrated mechanisms by which core fucosylation modulates oncogenic signaling, metabolic reprogramming, and immune evasion remain poorly understood. This review synthesizes recent advances to establish a unified framework for understanding the dual role of core fucosylation in liver physiology and pathology, and evaluates its translational potential for precision medicine. At the molecular level, FUT8’s unique catalytic specificity makes core fucosylation an irreplaceable modification, as evidenced by the perinatal lethality and severe organ dysfunction in Fut8 knockout mice. In hepatocellular carcinoma, genomic amplification of guanosine 5'-diphosphate-fucose biosynthetic enzymes provides metabolic support for aberrant core fucosylation. FUT8 expression is tightly regulated by a multi-layered network: transcriptional activation via Wnt/β‑catenin and wild-type p53, epigenetic upregulation by lncRNAs, post-transcriptional repression by miR-122-5p and miR-34a, and virus-specific induction by hepatitis B virus/hepatitis C virus. Physiologically, core fucosylation maintains liver homeostasis through four core mechanisms: it acts as a molecular switch for epidermal growth factor receptor/hepatocyte growth factor receptor signaling to enable liver regeneration; directs polarized secretion of hepatocyte-derived glycoproteins into bile ducts; modulates cholesterol metabolism via the hepatocyte nuclear factor 1α-proprotein convertase subtilisin/kexin type 9-low density lipoprotein receptor axis; and regulates aging through insulin‑like growth factor 1 receptor signaling. Pathologically, core fucosylation exhibits context-dependent dual functions: in liver fibrosis, FUT8 upregulation in hepatic stellate cells forms a negative feedback loop that limits excessive fibrogenesis; in hepatocellular carcinoma, however, aberrant FUT8 overexpression drives cell-autonomous malignancy by constitutively activating epidermal growth factor/hepatocyte growth factor receptor, transforming growth factor‑β/Smad, and Wnt/β‑catenin pathways, while simultaneously establishing a multi-layered immune evasion network by stabilizing programmed cell death ligand 1 and cluster of differentiation 47, and impairing natural killer cell homeostasis via interleukin‑2 receptor β glycosylation. Clinically, stage-specific core fucosylation biomarkers enable non-invasive monitoring of liver disease progression: low molecular mass kringle-Fc fusion protein outperforms conventional markers for early fibrosis detection, while alpha-fetoprotein-L3 and novel glycopeptides (α‑2‑macroglobulin N‑linked glycosylation site 1424, lumican core fucosylated peptide) significantly improve early hepatocellular carcinoma diagnosis, especially in alpha-fetoprotein-negative patients. Next-generation detection technologies (chemoenzymatic labeling, site-specific mass spectrometry) overcome the specificity limitations of traditional lectin assays. Therapeutically, four promising strategies are emerging: small-molecule FUT8 inhibitors, afucosylated antibodies with enhanced antibody‑dependent cellular cytotoxicity, Fuc-modified targeted drug delivery systems, and core fucose-specific lectins for NASH treatment. The core challenge for clinical translation lies in FUT8’s inherent “double-edged sword” effect, as systemic inhibition disrupts its essential physiological functions beyond pathological roles. Long-term systemic FUT8 blockade not only impairs post-injury liver regeneration by abrogating epidermal growth factor/hepatocyte growth factor receptor signaling but also disrupts cholesterol homeostasis via the hepatocyte nuclear factor 1α-proprotein convertase subtilisin/kexin type 9-low density lipoprotein receptor axis, leading to dyslipidemia and altered bile secretion. Critically, it compromises immune surveillance by destabilizing interleukin‑2 receptor β on natural killer cells, reducing their cytotoxic activity against malignant and virally infected cells, and impairs IgG Fc-mediated effector functions, increasing susceptibility to infections. This fundamental trade-off between therapeutic efficacy and systemic toxicity necessitates a paradigm shift from non-specific global inhibition to precision modulation of pathological core fucosylation. By addressing these critical challenges, FUT8-mediated core fucosylation has the potential to transform liver disease management from late-stage intervention to early detection and precision therapy, ultimately improving patient outcomes and reducing the global burden of liver diseases.
6.Guidelines for the perioperative diagnosis and treatment of oncogene-driven non-small cell lung cancer (2026)
Weidong WANG ; Yongbin LIN ; Hui TIAN ; Gaofeng LI ; Shun XU ; Yongde LIAO ; Haitao MA ; Junfeng LIU ; Chundong GU ; Xiaolong YAN ; Shumin WANG ; Daqiang SUN ; Jianyang LIU ; Tao XUE ; Shaohua MA ; Zhigang LI ; Shuanghu YUAN ; Gen LIN ; Ling CAI ; Jianping ZHOU ; Wenzhao ZHONG ; Naixin LIANG ; Yi HAN ; Junfeng WANG ; Weidong ZHANG ; Xin WANG ; Lianjuan CHEN ; Lunxu LIU ; Xiuyi ZHI ; Lanjun ZHANG
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(09):1337-1353
Lung cancer constitutes the most prevalent and lethal malignant tumor in China. Approximately 85% of lung cancer diagnoses correspond to the non-small cell histological subtype [non-small cell lung cancer (NSCLC)]. Despite surgery being the mainstay for early-stage disease, postoperative recurrence remains high and adjuvant chemotherapy offers limited benefit. In recent years, targeted therapy has demonstrated substantial advantages in driver mutation-positive NSCLC. To this end, the Lung Cancer Medical Education Committee of the Chinese Medical Education Association developed guidelines based on a systematic review of evidence through November 2025, using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach and a modified Delphi method. Focusing on epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK), and addressing ROS proto-oncogene 1 (ROS1), B-Raf proto-oncogene serine/threonine kinase (BRAF) V600E mutation, and mesenchymal-epithelial transition factor (MET) exon 14 (METex14) skipping, the guideline covers molecular testing, neoadjuvant/adjuvant therapy, perioperative strategies, minimal residual disease monitoring, and postoperative surveillance. It defines testing requirements, specifies stage-directed and subtype-specific treatments, and standardizes minimal residual disease monitoring. These recommendations emphasize precision and feasibility to improve survival and quality of life.
7.Trends in Oncomelania hupensis distribution in Yixing City, Jiangsu Province from 2008 to 2024
Jing LIANG ; Zhi-qiang XUE ; Xue-bing LI ; Di WU ; Han WANG
Acta Parasitologica et Medica Entomologica Sinica 2026;33(3):168-172
Objective To investigate changes in the distribution of Oncomelania hupensis snails in Yixing City, Jiangsu Province, from 2008 to 2024, and to provide insights to guide formulation of O. hupensis snail investigation and surveillance programs. Methods Data from O. hupensis snail surveys in Yixing City from 2008 to 2024 were collected. Trends in snail habitat site numbers, snail-infested areas, proportion of total area with snail habitats, occurrence of frames with living snails, and density of living snails in snail habitats in hilly regions of Yixing City were evaluated from 2008 to 2024 by applying a Joinpoint regression model to collect annual percent change (APC) and average annual percent change (AAPC) data. Results From 2008 to 2024, a total of 193.815 hm2 of snail-infested area was found within Yixing City, of which 191.765 hm2 (accounting for 98.94%) was distributed in hilly regions. A total of 344 snail infestation sites in hilly regions were identified. The average occurrence rate of living snail frames in snail habitats was 8.650% and the average living snail density in snail habitats was 0.246 per 0.1 m2. No Oncomelania snails were positively identified. The number of snail habitat sites in hilly regions of Yixing City showed no significant decreasing trend (AAPC=-2.8%, P=0.527). Similarly, no significant increasing trend in snail-infested area (APC=AAPC=5.7%, P=0.328) was found. The occurrence rate of living snail frames in snail habitats showed no significant increasing trend (APC=AAPC=5.1%, P=0.583). Living snail density in snail habitats also showed no significant increasing trend (APC=AAPC=3.2%, P=0.598). Conclusions From 2008 to 2024, snail infestation has persisted in the hilly areas of Yixing City with an unclear variation trend. The quality of snail investigation and snail surveillance system should be strengthened to permit timely identification of hidden dangers and rapid risk responses, thereby preventing schistosomiasis outbreaks.
8.Effects of Wenfei Jiangzhuo Formula on mitochondrial function of Aβ25-35-induced BV-2 cells based on PGAM5-Drp1 axis
Ding ZHANG ; Zhi-han HU ; Ke-qing ZHOU ; Wei CHEN ; Hong-ling QING ; Jun-jun XIANG ; Yue-qiang HU
Chinese Traditional Patent Medicine 2025;47(8):2558-2565
AIM To investigate the effects of Wenfei Jiangzhuo Formula on mitochondrial function of Aβ25-35-induced BV-2 cells.METHODS In the establishment of cell model of Alzheimer's disease(AD)using Aβ25-35 on the BV-2 cells,the optimal concentration and time point of Aβ25-35 intervention were determined;and the groups for the intervention of LFHP-1c group(inhibitor)or the serum containing Wenfei Jiangzhuo Formula were set up.The detection of the optimal intervention concentration and time point by CCK-8 assay;the observation of cell migration and apoptosis by Transwell assay and Hoechst 33342 staining;the detection of the positive expressions of PGAM5 and Drp1 by immunofluorescence;and the detection of cellular PGAM5,Drp1,OPA1,and Mfn1/2 mRNA and protein expressions by RT-qPCR and Western blot were conducted.RESULTS The best AD cell model was established by 48 h exposure to 5 μmol/L of Aβ25-35,and most active cell viability was achieved with the 48 h use of serum containing 20%Wenfei Jiangzhuo Formula.Compared with the control group,the model group displayed decreased number of cell migration,more bright blue positive apoptotic cells,increased number of PGAM5 and Drp1 positive cells and their mRNA and protein expressions(P<0.05);and decreased mRNA and protein expressions of OPA1 and Mfn1/2(P<0.05).Compared with the model group,the groups intervened with the medicines shared increased number of cell migration,less bright blue positive apoptotic cells,decreased number of PGAM5 and Drp1 positive cells and their mRNA and protein expressions(P<0.05);and elevated OPA1 and Mfn1/2 mRNA and protein expressions(P<0.05).CONCLUSION Wenfei Jiangzhuo Formula exerts cerebroprotective effects to improve cognition by reducing cell damage and improving the balance of mitochondrial homeostasis through PGAM5-Drp1 axis in AD model.
9.Multicolor Fluorescent Copper Nanoclusters/Starch Composites and Their Application in Fingermark Development
Chuan-Jun YUAN ; Ming LI ; Yi-Fei SUN ; Jia-Ming LYU ; Zhi-Bo GAO ; Shi-Qiang SUN ; Pei-Liang HAN ; Feng-He LIU
Chinese Journal of Analytical Chemistry 2025;53(1):55-64,中插1-中插3
On the basis of that the fluorescence wavelength of copper nanoclusters(CuNCs)could cover the entire visible region,multicolor fluorescent CuNCs/starch composites were prepared and applied in fingermark development.With L-glutathione as the reducing agent and protective ligand,blue emissive and orange emissive CuNCs solutions were obtained in alkaline solutions at 90℃and 25℃,respectively.With the aggregation-induced emission effect induced by ethanol as a poor solvent,the fluorescence of orange emissive CuNCs with a higher intensity was achieved in an ethanol-water solution.With ascorbic acid as the reducing agent and 3-mercaptopropionic acid as the protective agent,green emissive CuNCs solution was prepared in an acid solution.Particle morphologies,chemical compositions and optical properties of these three CuNCs above were investigated using physical characterization and spectroscopic analysis,indicating that well-dispersed CuNCs had excellent photoluminescent properties.These CuNCs solutions were combined with starch to form composite powders by simply drying.The influences of the type of CuNCs and the ratio of CuNCs to starch on the emission wavelength and fluorescence intensity of the products were studied.The obtained CuNCs/starch composites could emit blue,green and orange fluorescence under 365 nm ultraviolet light,respectively,which were suitable for fingermark development.Minutiae and partial level-3 features of latent fingermarks could be effectively developed.High-quality fluorescence fingermark images would be captured using appropriate optical filters to eliminate background interference of various substrates.
10.Quantification of Atmospheric Total Reactive Nitrogen Oxides by Thermal Decomposition-Broadband Cavity Enhanced Absorption Spectroscopy
Dou SHAO ; Min QIN ; Wu FANG ; Bao-Bin HAN ; Ke TANG ; Jian-Ye XIE ; Xia-Dan ZHAO ; Zhi-Tang LIAO ; En-Bo REN
Chinese Journal of Analytical Chemistry 2025;53(3):387-396
Nitrogen oxides(NOx=NO+NO2)are important precursors of ozone(O3),and NOx and its oxides together constitute reactive nitrogen oxides(NOy)in the atmosphere.A comprehensive understanding of the total NOy level in the atmosphere is of great significance for a deeper understanding of the atmospheric nitrogen cycle and oxidation,as well as for formulating strategies for air pollution prevention and control.In this work,a thermal decomposition-broadband cavity enhanced absorption spectroscopy(TD-BBCEAS)technique for online measurement of total NOy in the atmosphere was developed.With this method,the NOy was efficiently converted into NO2,and the total NOy concentration in the atmosphere was indirectly obtained by measuring NO2.Focusing on the key factors affecting the measurement of total NOy,the influence of NO titration efficiency and other NOy component TD efficiency on measurement accuracy was emphasized.By changing the oxygen(O2)flow rate through the mercury lamp to alter the O3 concentration for titrating NO,the conversion efficiency of NO was evaluated.At O2 flow rate of 6 mL/min,the conversion efficiency of NO was greater than 99%.TD efficiency testing and analysis on NO2,peroxyacetyl nitrate(PAN),nitric acid(HNO3),and nitrous acid(HONO),which account for a large proportion of atmospheric NOy components,was carried out using 680℃as the optimal TD temperature for efficient conversion of NOy.With NO and HONO sample gases as typical verification gases,the conversion efficiency of NOy and the accuracy of NOy measurement by TD-BBCEAS system were verified by switching the on and off modes of mercury lamp and TD device.At integration time of 60 s,the detection limit of the system for NOy was 2.83×1010 molecules/cm3(60 s,2σ).A comparative measurement of actual atmospheric NOy was conducted between the TD-BBCEAS system and the NOy analyzer.The observation results showed a correlation coefficient(R2)of 0.98 and a slope of 0.93,further verifying the feasibility and accuracy of applying the TD-BBCEAS system to measurement of total NOy.


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