Multi-environment evaluations across ecological regions reveal climate and soil effects on amides contents in Chinese prickly ash peels (Zanthoxylum bungeanum Maxim.).

BACKGROUND: Environmental factors difference is the key factor for the difference in the production, transformation and accumulation of effective components in plants. UPLC-MS/MS and multivariate statistical methods were applied to describe the region difference of amides compounds in Chinese prickly ash peels from different regions and their correlation with climatic factors and soil factors. RESULTS: Amides compounds contents were significantly higher in high altitude areas, with obvious altitude change trend. Two ecotypes were classified based on the amides compounds contents, one was the high altitude-cool type from Qinghai, Gansu, Sichuan and western Shaanxi province, and the other one was low altitude-warm type from eastern Shaanxi, Shanxi, Henan, Hebei and Shandong province. Amides compounds content were negatively correlated with annual mean temperature, max temperature of warmest month, mean temperature of wettest quarter and mean temperature of warmest quarter (P < 0.01). Except for hydroxy-γ-sanshool and ZP-amide A, the residual amides contents were significantly positively correlated with organic carbon, available nitrogen, phosphorus and potassium in soil and negatively correlated with soil bulk density. Low temperature, low precipitation and high organic carbon in soil were conducive to amides accumulation. CONCLUSIONS: This study aided in site specific exploration of high amides contents yielding samples, enriched the environment factors effects on amides compounds, and provided scientific foundation for the improvement of Chinese prickly ash peels quality and the location of high-quality production areas.

Self-assembled wide bandgap nanocoatings enabled outstanding dielectric characteristics in the sandwich-like structure polymer composites.

Polymer dielectrics are insulators or energy storage materials widely used in electrical and electronic devices. Polymer dielectrics are needed with outstanding dielectric characteristics than current technologies. In this study, the self-assembly of boron nitride nanosheets (BNNSs) was applied to form an inorganic-organic nanocoating on various common polymer dielectrics. It is inexpensive and easy to fabricate this thin coating on a large scale. The coating has a wide bandgap and thus can significantly improve the breakdown strength of polymer dielectrics. The charge characteristics and trapping parameters of nano-domains on the surfaces of polymer dielectrics were measured, and the coating had shallow trap levels. This facilitated the dissipation of surface charges and thus greatly increased the flashover voltage. The coating also effectively improved the temperature stability and dielectric constant of the polymer dielectric. This nanocoating shows potential as a method to effectively improve the dielectric characteristics of polymer dielectrics and outperform existing composite polymer dielectrics, which are crucial for large-scale applications in energy storage and power and electronic devices.

Evaluation of climate factors affecting the quality of red huajiao (Zanthoxylum bungeanum maxim.) based on UPLC-MS/MS and MaxEnt model.

Through field investigation, UPLC-MS/MS technology and MaxEnt model were performed to predict the suitable distribution area for red huajiao (Zanthoxylum bungeanum maxim.) in China from 2021 s to 2060 s, and evaluate the effects of climate factors on the quality of red huajiao. The results demonstrated that mean temperature of the coldest quarter and min temperature of the coldest month were the most important environmental variables influencing red huajiao distribution. Suitable habitats for red huajiao were located mainly in dry and hot valley zone in the Qinba Mountains and the semi-humid and semi-arid areas of the Loess Plateau. The amides contents were higher in high suitability areas, while it was decreased in medium and low suitability areas, and temperature, wind speed and precipitation played a key role in their accumulation. This investigation was of great significance for the planting area optimization, quality control, benefit improvement and industrial development of red huajiao.

Evaluating the Impacts of Climate Factors and Flavonoids Content on Chinese Prickly Ash Peel Color Based on HPLC-MS and Structural Equation Model.

Climate affects Chinese prickly ash peel color directly through temperature and illumination and indirectly influences it through its effect on flavonoid compounds. In this study, a comprehensive evaluation strategy based on high performance liquid chromatography-mass spectrometry (HPLC-MS) technology and a structural equation model was applied to evaluate the effects of climate factors and flavonoids on Chinese prickly ash peel color. There were obvious geographical variations of peel color and flavonoid compounds with an obvious east-west distribution trend which were divided into high-altitude type and low-altitude type. Through path analysis, the wind speed, temperature and annual sunshine duration were found to be the key environmental factors affecting the flavonoids content and peel color, and their direct effects were higher than their indirect effect. Based on HPLC-MS technology and a structural equation model, correlation models of climatic factors and flavonoids with peel color were established, and the factors that had greater weight on pericarp color were obtained. Our results provide experimental evidence that climate factors affect the peel color by affecting flavonoid biosynthesis and accumulation, reveal the geographical variation of peel color and flavonoid component contents in Chinese prickly ash peel, establish a quantization color method for rapid evaluation of peel quality, expand on the influence of climatic factors on flavonoids content and peel coloration and promote agricultural practice in areas with similar climatic conditions.

Chemotaxonomic Identification of Key Taste and Nutritional Components in 'Shushanggan Apricot' Fruits by Widely Targeted Metabolomics.

The chemotypic and the content variation in taste substances and nutrients in 'Shushanggan apricot' fruits were detected by UPLC-MS/MS. A total of 592 compounds were identified, of which sucrose contributed mainly to the sweet taste and malic acid and citric acid were important organic acids affecting sweet-sour taste. γ-linolenic acid, α-linolenic acid and linoleic acid were the dominant free fatty acids, and neochlorogenic acid and chlorogenic acid were the predominant phenolic acids. Fruit taste was positively correlated with sucrose and negatively correlated with malic acid and citric acid. The differential metabolites were significantly enriched in the biosynthesis of amino acids and 2-oxocarboxylic acid metabolism pathways, regulating the sugar and organic acid biosynthesis. Taste and nutrient differences could be revealed by variations in composition and abundance of carbohydrates, organic acids and amino acids. The purpose of this study was to provide a comprehensive chemical characterization of taste and nutrient compounds in 'Shushanggan apricot' fruits.

Regulation mechanisms of flavonoids biosynthesis of Hancheng Dahongpao peels (Zanthoxylum bungeanum Maxim) at different development stages by integrated metabolomics and transcriptomics analysis.

BACKGROUND: Flavonoids have strong free radical scavenging and antioxidant capacity. The high abundance of flavonoids in Chinese prickly ash peels have many benefits to human health. In this study, 'Hancheng Dahongpao', a main cultivar, was taken as materials to investigate the flavonoids biosynthesis mechanism of Zanthoxylum bungeanum Maxim at three key development stages by integration of metabolomics and transcriptomics analysis. RESULTS: A total of 19 differentially accumulated metabolites were identified, the key flavonoids compounds were kaempferol, quercetin and their glycoside derivatives, and two major anthocyanins (peonidin O-hexoside and peonidin 3-O-glucoside). 5 gene networks/modules including 15 important candidate genes were identified, which was highly correlated with flavonoids. Among these genes, ZM-163828 and ZM-184209 were strongly correlated with kaempferol and quercetin, and ZM-125833 and ZM-97481 were controlled the anthocyanins biosynthesis. Moreover, it was shown that MYB-ZM1, MYB-ZM3, MYB-ZM5, MYB-ZM6 and MYB-ZM7 coordinately controlled flavonoids accumulation through regulating the structural genes. CONCLUSIONS: Generally, this study systematically revealed the flavonoids metabolic pathways and candidate genes involved in flavonoids biosynthesis and laid a foundation for the potential targets for the breeding of new valuable Chinese prickly ash cultivars.

Quality Evaluation of Wild Germplasm of Chinese Prickly Ash (Zanthoxylum bungeanum Maxim) from Qinling Mountains at Different Elevations Based on HPLC-Fingerprint.

Wild Chinese prickly ash resources provide a valuable genetic resource for Zanthoxylum bungeanum Maxim improvement and breeding. The Qinling Mountains was an abundant source for wild Chinese prickly ash. In this study, the phenolic and flavonoid compounds of wild germplasm resources from different altitudes and six cultivated varieties were analyzed by high performance liquid chromatography (HPLC). The chromatograms of them were essentially consistent, although their chemical composition contents were greatly different. The thirty samples were divided into three categories through the hierarchical clustering analysis. Catechin, hyperoside and quercitrin were considered to be key compounds for the quality evaluation, and by contrast, the wild samples with an altitude of 2300±50 m (Group IV) had the highest content of key compounds, and presented stronger antioxidant activity and antibacterial ability, indicating that these wild samples could be identified as the excellent breeding resources. This is the first time to evaluate the quality of wild Chinese prickly ash at different altitudes in Qinling Mountains. These excellent wild germplasm resources provided substantial potential accessions for use directly in Chinese prickly ash breeding programs.

Chemotaxonomic variation in volatile component contents and their correlation between climate factors in Chinese prickly ash peels (Zanthoxylum bungeanum Maxim.).

In this study, we analyzed the characteristics of volatile compounds of Chinese prickly ash peels with different climate conditions and their correlation. The data revealed that the contents of limonene and linalool in peels from southwest and northwest regions were higher, and the aroma was stronger, while the contents of ß-myrcene and (E)-ocimene in them from north, east and central China were higher, and the spicy flavor was heavier. Hierarchical cluster analysis demonstrated that the classification had geographical continuity. Through the correlation analysis and path analysis, it was found that the contents of volatile compounds were closely related to the climatic factors. The influence of wind speed and annual average temperature on volatile substances was greater than that of annual average precipitation and annual sunshine duration. This enriched the effect of climatic factors on the accumulation of volatile substances, and promoted the agriculture practices in area having similar climate conditions.

Surgery combined with 125I brachytherapy for treatment of carcinoma ex pleomorphic adenoma of the parotid gland.

OBJECTIVE: The aim of this study was to investigate the effectiveness and safety of surgery combined with 125I seed brachytherapy for treatment of carcinoma ex pleomorphic adenoma (CXPA) of the parotid gland and to identify the factors associated with prognosis. STUDY DESIGN: We conducted a retrospective analysis of data of patients with CXPA of the parotid gland treated with surgery plus 125I seed brachytherapy at the Peking University School of Stomatology Hospital between December 2003 and July 2018. RESULTS: Fifty-five patients (median age, 51 years) were included in the study. Median follow-up was 50.5 months. The 3-, 5-, and 10-year overall survival rates were 91.1%, 91.1%, and 81.5%, respectively. The 3-, 5-, and 10-year local control rates were all 85.2%. Grades 1-3 adverse effects occurred in 22 patients; no grade 4 reactions occurred. T stage, N stage, tumor invasiveness, perineural invasion, and surgical margins significantly affected local control rates. Lymph node metastasis and perineural invasion were independent predictors of poor local control. Lymph node metastasis was an independent predictor of poor survival. CONCLUSIONS: Surgery plus 125I seed brachytherapy appears to be an effective and safe treatment for CXPA of the parotid gland. T stage, N stage, tumor invasiveness, and perineural invasion are factors influencing prognosis.

Surgery combined with iodine-125 interstitial brachytherapy for treatment of parotid adenoid cystic carcinoma: A single-institution experience.

PURPOSE: The purpose of this study was to analyze the effectiveness and safety of the combination of surgery plus postoperative iodine-125 interstitial brachytherapy for treatment of adenoid cystic carcinoma (ACC) of the parotid. METHODS AND MATERIALS: This study included a retrospective analysis of the data of patients who underwent postoperative iodine-125 interstitial brachytherapy for histology-confirmed ACC of the parotid between January 2002 and November 2018 in Peking University Hospital of Stomatology. Acute and long-term radiation-related toxicities were assessed by the criteria of the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer. Multivariate analysis was used to identify the factors affecting overall survival, disease-free survival (DFS), and distant metastasis-free survival (DMFS). RESULTS: A total of 86 patients (53 women; median age 50 years, SD = 13.1) were included. Median followup was for 45.5 months. About half the patients (44/86, 51.3%) had clinical stage IV disease. Local recurrence occurred in 11 of 86 (12.8%) patients. No patient had nodal metastases in the followup period. The five- and 10-year DFS rates were 74.8% and 66.6%, respectively. The mean DMFS was 60.6 months. On multivariate analysis, preoperative facial palsy, type of surgery, perineural spread (PNS), and distant metastases were independent prognostic factors for DFS; preoperative facial palsy, nodal metastases, and PNS were independent prognostic factors for overall survival; and preoperative facial palsy, type of surgery, PNS, and pathological type were independent prognostic factor for DMFS. CONCLUSIONS: The combination of surgery and iodine-125 interstitial brachytherapy appears to be an effective and safe treatment for primary ACC of the parotid.

Diagnostic value of navigation-guided core needle biopsy in deep regions of the head and neck with focal FDG uptake on 18F-FDG PET/CT.

PURPOSE: The aim of this study was to evaluate the feasibility and diagnostic accuracy of core needle biopsy (CNB) in patients with focal fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) in deep regions of the head and neck, with the guidance of infrared navigation integrated with PET. MATERIALS AND METHODS: Patients with suspected primary or recurrent malignancies of the head and neck on PET/CT, from June 2016 to December 2018, were included. Before CNB, the region of interest was delineated and the ideal needle entry points, target sites, and a number of trajectories were designed on iPlan CMF 3.0. CNB was performed with the guidance of infrared navigation integrated with PET, according to the pre-plan. Sensitivity and diagnostic accuracy were analyzed by comparing the biopsy results with the final diagnosis. RESULTS: Thirty-one consecutive patients were included. Among the 31 lesions, 18 were skull base, six were infratemporal fossa, and seven were maxillary region. The median values for SUVmax, SUVmean, and MTV were 6.09 (range: 1.43-24.67), 3.41 (range: 0.38-20.96), and 25.83 (range: 3.54-361.94) for the 31 lesions, respectively. Combined needle approaches were employed, including temporal (nine), subzygomatic (19), paramaxillary (11), and retromandibular (16) approaches. The depths of the 31 deep-region lesions, measured from the needle entry site on the skin to the target point, ranged from 1.33 cm to 7.82 cm (median 4.25 cm). There were three non-diagnostic lesions resulting from CNB, and these were all skull base. The diagnostic accuracy was 90.3%, while the sensitivity was 88%. According to the binary logistic regression for the final diagnosis, the only significant parameter was SUVmax. CONCLUSION: With the guidance of navigation integrated with PET, CNB is a feasible and accurate diagnostic modality, which is also an alternative to open biopsy in patients with suspected primary or recurrent malignancies in deep regions of the head and neck on PET/CT.

Transcriptome and metabolome analyses reveal the regulation of peel coloration in green, red Chinese prickly ash (Zanthoxylum L.).

Peel colour is an important external economic characteristic of Chinese prickly ash cultivars (Zanthoxylum bungeanum Maxim.). To gain insight into their coloration mechanisms, we performed an integrated analysis of green and red peels using combined metabolomic and transcriptomic analyses. Pelargonin-O-hexoside-O-rhamnoside-O-hexoside, pelargonidin 3,5-diglucoside, peonidin O-hexoside, cyanidin O-syringic acid and peonidin 3-O-glucoside were found to be the key anthocyanins. Transcriptome data indicated that the anthocyanidin synthase genes and UDP-glucose flavonoid 3-O-glucosytransferase genes were significantly increased to promote the redness of the peels. In addition, we discussed the role of R2R3-MYB transcription factors in coloration, of which the c80935 and c226097 genes may be the key regulatory factors for anthocyanin biosynthesis. Generally, this is the first study to identify and reveal the main anthocyanins in Chinese prickly ash peels during different developmental periods. The results of this research lay the foundation for understanding the regulation of coloration in Chinese prickly ash peels.

Subcutaneous Injection of Hyaluronic Acid to Decrease Acute Skin Toxicity After Adjuvant Interstitial Brachytherapy in Parotid Gland Cancer Patients: A Nonrandomized Controlled Trial.

PURPOSE: The aim was to evaluate the safety and efficacy of subcutaneous injection of hyaluronic acid in decreasing acute skin toxicity after adjuvant interstitial brachytherapy in parotid gland cancer patients. MATERIALS AND METHODS: Patients with histologically proven parotid gland cancer who would be treated with adjuvant interstitial brachytherapy were included in this nonrandomized controlled trial. Participants were nonrandomly divided into the experimental group and control group. Participants in the experimental group received an injection of hyaluronic acid subcutaneously immediately after interstitial brachytherapy during the operation. Acute toxicity was evaluated in the first 2 months. RESULTS: Thirty consecutive participants were included from April to September 2018. Twenty participants were in the experimental group, and 10 were in the control group. The median volume of hyaluronic acid was 8 mL (range, 4 to 11 mL). In total, the incidence of acute skin toxicity was 40% (8 of 20 patients) and 100% (10 of 10 patients) in the experimental group and control group, respectively. The difference in the dose delivered to 90% of the target volume of the affected skin was significant between the pre-plan (mean, 36.93 Gy) and the actuarial quality verification (mean, 27.70 Gy) in the experimental group (P = .004). The difference in scoring of acute skin toxicity was significant between the experimental and control groups (P = .001). No clear correlation was found between the dose delivered to 90% of the target volume of the affected skin and the scoring of acute skin toxicity (P = .266). CONCLUSIONS: Subcutaneous injection of hyaluronic acid was safe and efficient in decreasing acute skin toxicity after adjuvant interstitial brachytherapy in parotid gland cancer patients according to the preliminary results.

Texture analysis of pretreatment [18F]FDG PET/CT for the prognostic prediction of locally advanced salivary gland carcinoma treated with interstitial brachytherapy.

BACKGROUND: The aim of this study was to evaluate the prognostic value of positron emission tomography (PET) parameters and the PET texture features of fluorine 18-fluorodeoxyglucose ([18F]FDG) uptake on pretreatment PET/computed tomography (CT) in patients with locally advanced salivary gland carcinoma treated with interstitial brachytherapy. METHODS: Forty-three patients with locally advanced salivary gland carcinoma of the head and neck were treated with 125I interstitial brachytherapy as the sole modality and underwent [18F]FDG PET/CT scanning before treatment. Tumor segmentation and texture analysis were performed using the 3D slicer software. In total, 54 features were extracted and categorized as first-order statistics, morphology and shape, gray-level co-occurrence matrix, and gray-level run length matrix. Up to November 2018, the follow-up time ranged from 6 to 120 months (median 18 months). Cumulative survival was calculated by the Kaplan-Meier method. Factors between groups were compared by the log-rank test. Multivariate Cox regression analysis with a backward conditional method was used to predict progression-free survival (PFS). RESULTS: The 3- and 5-year locoregional control (LC) rates were 55.4% and 37.0%, respectively. The 3- and 5-year PFS rates were 51.2% and 34.1%, respectively. The 3- and 5-year overall survival (OS) rates were 77.0% and 77.0%, respectively. Univariate analysis revealed that minimum intensity, mean intensity, median intensity, root mean square, and long run emphasis (LRE) were significant predictors of PFS, whereas clinicopathological factors, conventional PET parameters, and PET texture features failed to show significance. Multivariate Cox regression analysis showed that minimum intensity and LRE were significant predictors of PFS. CONCLUSIONS: The texture analysis of pretreatment [18F]FDG PET/CT provided more information than conventional PET parameters for predicting patient prognosis of locally advanced salivary gland carcinoma treated with interstitial brachytherapy. The minimum intensity was a risk factor for PFS, and LRE was a favorable factor in prognostic prediction according to the primary results.

Antibacterial mode of fibrauretine and synergistic effect with kanamycin against multi-drug resistant Escherichia coli.

OBJECTIVE: The present study evaluated the antibacterial activity and mode of action of fibrauretine on Escherichia coli (E. coli) and Staphylococcus aureus, and synergistic effect with kanamycin against multi-drug resistant E. coli. RESULTS: The fibrauretine exhibited inhibitory effect on the growth of the tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration of 2.5-5 and 5-10 mg/ml, respectively. Morphological changes of cell microstructure were observed after adding fibrauretine at MIC. The mode of action was further confirmed by measuring release of 260-nm absorbing materials and extracellular potassium ions. Checkerboard dilution test suggested that fibrauretine exhibited synergistic activity when combined with kanamycin (FICI ranging from 0.5625 to 0.625). CONCLUSIONS: Our results indicated that fibrauretine exerted synergistic effect with kanamycin and its antibacterial mode of action mainly attributed to disruption of cell membrane integrity.

Efficacy of combined surgery and 125 I seed brachytherapy for treatment of primary mucoepidermoid carcinoma of the parotid gland.

BACKGROUND: This study aimed to determine the effectiveness and safety of surgery combined with postoperative 125 I seed brachytherapy for treatment of primary mucoepidermoid carcinoma (MEC) of the parotid gland. METHODS: Retrospective analysis of data of patients with MEC (n = 108) treated with surgery plus postoperative 125 I seed brachytherapy between 2004 and 2016. Overall survival (OS), disease-free survival (DFS), local control rate (LCR), distant metastasis, and radiation-associated toxicities were analyzed, and factors affecting outcomes were evaluated. RESULTS: The 5- and 10-year OS were 98.8% and 95.8%, respectively. The DFS and LCR at 5 and 10 years were all 91.4%. Age ≥ 60 years (hazard ratio [HR] = 6.86, 95% confidence interval [CI]: 1.54-30.55) and T4 disease (HR = 7.15, 95% CI: 1.40-36.52) were poor prognostic factors. Acute radiation-associated toxicities were minor. CONCLUSION: Surgery plus 125 I seed brachytherapy appears to be an effective treatment for parotid gland MEC, capable of providing satisfactory outcomes with few complications.

Characteristic differences in essential oil composition of six Zanthoxylum bungeanum Maxim. (Rutaceae) cultivars and their biological significance.

Great variations have been found in composition and content of the essential oil of Zanthoxylum bungeanum Maxim. (Rutaceae), resulting from various factors such as harvest time, drying and extraction methods (Huang et al., 2006; Shao et al., 2013), solvent and herbal parts used (Zhang, 1996; Cao and Zhang, 2010; Wang et al., 2011). However, in terms of artificial introduction and cultivation, there is little research on the chemical composition of essential oil extracted from Z. bungeanum Maxim. cultivars, which have been introduced from different origins. In this study, the composition and content of essential oil from six cultivars (I-VI) have been investigated. They were introduced and cultivated for 11 years in the same cultivation conditions. Cultivars were as followings: Qin'an (I) cultivar originally introduced from Qin'an City in Gansu Province; Dahongpao A (II) from She County in Hebei Province; Dahongpao B (III) from Fuping County; Dahongpao C (IV) from Tongchuan City; Meifengjiao (V) from Feng County; and, Shizitou (VI) from Hancheng City, in Shaanxi Province, China. This research is expected to provide a theoretical basis for further introduction, cultivation, and commercial development of Z. bungeanum Maxim.

Aminoglycoside susceptibility of Pasteurella multocida isolates from bovine respiratory infections in China and mutations in ribosomal protein S5 associated with high-level induced spectinomycin resistance.

Twenty-three isolates of Pasteurella multocida were tested for susceptibility to six aminoglycoside agents and screened by polymerase chain reaction for the presence of aminoglycoside resistance genes. In addition, mutations in the resistance-determining region of strains showing a high level of induced resistance to spectinomycin strains were examined. Susceptibility testing showed that all of the isolates were resistant to at least two types of aminoglycosides, and that the most effective antimicrobial was spectinomycin. The resistance genes aphA1, strB and aacA4 were present in all 23 isolates. In the three induced spectinomycin-resistant strains, a 9-bp deletion in rpsE that encodes ribosomal protein S5 was detected.

Whole genome sequencing of an ExPEC that caused fatal pneumonia at a pig farm in Changchun, China.

BACKGROUND: In recent years, highly frequent swine respiratory diseases have been caused by extraintestinal pathogenic Escherichia coli (ExPEC) in China. Due to this increase in ExPECs, this bacterial pathogen has become a threat to the development of the Chinese swine industry. To investigate ExPEC pathogenesis, we isolated a strain (named SLPE) from lesioned porcine lungs from Changchun in China, reported the draft genome and performed comparative genomic analyses. RESULTS: Based on the gross post-mortem examination, bacterial isolation, animal regression test and 16S rRNA gene sequence analysis, the pathogenic bacteria was identified as an ExPEC. The SLPE draft genome was 4.9 Mb with a G + C content of 51.7%. The phylogenomic comparison indicated that the SLPE strain belongs to the B1 monophyletic phylogroups and that its closest relative is Avian Pathogenic Escherichia coli (APEC) O78. However, the distribution diagram of the pan-genome virulence genes demonstrated significant differences between SLPE and APEC078. We also identified a capsular polysaccharide synthesis gene cluster (CPS) in the SLPE strain genomes using blastp. CONCLUSIONS: We isolated the ExPEC (SLPE) from swine lungs in China, performed the whole genome sequencing and compared the sequence with other Escherichia coli (E. coli). The comparative genomic analysis revealed several genes including several virulence factors that are ExPEC strain-specific, such as fimbrial adhesins (papG II), ireA, pgtP, hlyF, the pix gene cluster and fecR for their further study. We found a CPS in the SLPE strain genomes for the first time, and this CPS is closely related to the CPS from Klebsiella pneumoniae.

The deactivation mechanism of Pb on the Ce/TiO2 catalyst for the selective catalytic reduction of NOx with NH3: TPD and DRIFT studies.

It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E-R and L-H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L-H mechanism. The contributions of the L-H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.