SO2- and H2O-Tolerant Catalytic Reduction of NOx at a Low Temperature via Engineering Polymeric VOx Species by CeO2.

Selective catalytic reduction (SCR) of NOx over V2O5-based oxide catalysts has been widely used, but it is still a challenge to efficiently reduce NOx at low temperatures under SO2 and H2O co-existence. Herein, SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature has been originally demonstrated via engineering polymeric VOx species by CeO2. The polymeric VOx species were tactfully engineered on Ce-V2O5 composite active sites via the surface occupation effect of Ce, and the obtained catalysts exhibited remarkable low-temperature activity and strong SO2 and H2O tolerance at 250 °C. The strong interaction between Ce and V species induced the electron transfer from V to Ce and tuned the SCR reaction via the E-R pathway between the NH4+/NH3 species and gaseous NO. In the presence of SO2 and H2O, the polymeric VOx species had not been hardly influenced, while the formation of sulfate species on Ce sites not only promoted the adsorption of NH4+ species and the reaction between gaseous NO and NH4+ but also facilitated the decomposition of ammonium bisulfate through weakening the strong bond between HSO4- and NH4+. This work provided a new strategy for SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature.

SO2-Induced Alkali Resistance of FeVO4/TiO2 Catalysts for NOx Reduction.

Selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR) is an efficient NOx abatement strategy, but deNOx catalysts suffer from serious deactivation due to the coexistence of multiple poisoning substances such as K, SO2, etc. in the flue gas. It is essential to understand the interaction among various poisons and their effects on NOx abatement. Here, we unexpectedly identified the K migration behavior induced by SO2 over K-poisoned FeVO4/TiO2 catalysts, which led to alkali-poisoning buffering and activity recovery. It has been demonstrated that the K would occupy both redox and acidic sites, which severely reduced the reactivity of FeVO4/TiO2 catalysts. After the sulfuration of the K-poisoned catalyst, SO2 preferred to be combined with the surface K2O, lengthened the K-OFe and K-OV, and thus released the active sites poisoned by K2O, thereby preserving an increase in the activity. As a result, for the K-poisoned catalyst, the conversion of NOx increased from 21 to 97% at 270 °C after the sulfuration process. This work contributes to the understanding of the specific interaction between alkali metals and SO2 on deNOx catalysts and provides a novel strategy for the adaptive use of one poisoning substance to counter another for practical NOx reduction.

Synergistic Catalytic Elimination of NOx and Chlorinated Organics: Cooperation of Acid Sites.

The synergistic catalytic removal of NOx and chlorinated volatile organic compounds under low temperatures is still a big challenge. Generally, degradation of chlorinated organics demands sufficient redox ability, which leads to low N2 selectivity in the selective catalytic reduction of NOx by NH3 (NH3-SCR). Herein, mediating acid sites via introducing the CePO4 component into MnO2/TiO2 NH3-SCR catalysts was found to be an effective approach for promoting chlorobenzene degradation. The observation of in situ diffuse reflectance infrared Fourier transform (in situ DRIFT) and Raman spectra reflected that the Lewis acid sites over CePO4 promoted the nucleophilic substitution process of chlorobenzene over MnO2 by weakening the bond between Cl and benzene ring. Meanwhile, MnO2 provided adequate Brønsted acid sites and redox sites. Under the cooperation of Lewis and Brønsted acid sites, relying on the rational redox ability, chlorobenzene degradation was promoted with synergistically improved NH3-SCR activity and selectivity. This work offers a distinct pathway for promoting the combination of chlorobenzene catalytic oxidation and NH3-SCR, and is expected to provide a novel strategy for synergistic catalytic elimination of NOx and chlorinated volatile organic compounds.

Improved NO x Reduction in the Presence of SO2 by Using Fe2O3-Promoted Halloysite-Supported CeO2-WO3 Catalysts.

Currently, selective catalytic reduction (SCR) of NO x with NH3 in the presence of SO2 by using vanadium-free catalysts is still an important issue for the removal of NO x for stationary sources. Developing high-performance catalysts for NO x reduction in the presence of SO2 is a significant challenge. In this work, a series of Fe2O3-promoted halloysite-supported CeO2-WO3 catalysts were synthesized by a molten salt treatment followed by the impregnation method and demonstrated improved NO x reduction in the presence of SO2. The obtained catalyst exhibits superior catalytic activity, high N2 selectivity over a wide temperature range from 270 to 420 °C, and excellent sulfur-poisoning resistance. It has been demonstrated that the Fe2O3-promoted halloysite-supported CeO2-WO3 catalyst increased the ratio of Ce3+ and the amount of surface oxygen vacancies and enhanced the interaction between active components. Moreover, the SCR reaction mechanism of the obtained catalyst was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy. It can be inferred that the number of Brønsted acid sites is significantly increased, and more active species could be produced by Fe2O3 promotion. Furthermore, in the presence of SO2, the Fe2O3-promoted halloysite-supported CeO2-WO3 catalyst can effectively prevent the irreversible bonding of SO2 with the active components, making the catalyst exhibit desirable sulfur resistance. The work paves the way for the development of high-performance SCR catalysts with improved NO x reduction in the presence of SO2.

Structural and functional brain changes in perimenopausal women who are susceptible to migraine: a study protocol of multi-modal MRI trial.

BACKGROUND: As a common clinical symptom that often bothers midlife females, migraine is closely associated with perimenopause. Previous studies suggest that one of the most prominent triggers is the sudden decline of estrogen during perimenopausal period. Hormone replacement therapy (HRT) is widely used to prevent this suffering in perimenopausal women, but effective diagnostic system is lacked for quantifying the severity of the diseaase. To avoid the abuse and overuse of HRT, we propose to conduct a diagnostic trial using multimodal MRI techniques to quantify the severity of these perimenopausal migraineurs who are susceptible to the decline of estrogen. METHODS: Perimenopausal women suffering from migraine will be recruited from the pain clinic of our hospital. Perimenopausal women not suffering from any kind of headache will be recruited from the local community. Clinical assessment and multi-modal MR imaging examination will be conducted. A follow up will be conducted once half year within 3 years. Pain behavior, neuropsychology scores, fMRI analysis combined with suitable statistical software will be used to reveal the potential association between these above traits and the susceptibility of migraine. DISCUSSION: Multi-modal imaging features of both healthy controls and perimenopausal women who are susceptible to estrogen decline will be acquired. Imaging features will include volumetric characteristics, white matter integrity, functional characteristics, topological properties, and perfusion properties. Clinical information, such as basic information, blood estrogen level, information of migraine, and a bunch of neurological scale will also be used for statistic assessment. This clinical trial would help to build an effective screen system for quantifying the severity of illness of those susceptible women during the perimenopausal period. TRIAL REGISTRATION: This study has already been registered at Clinical Trials. gov (ID: NCT02820974 ). Registration date: September 28th, 2014.

Water-bath assisted convective assembly of aligned silver nanowire films for transparent electrodes.

Manipulating Ag nanowire (AgNW) assembly to tailor the opto-electrical properties and surface morphology could improve the performance of next-generation transparent conductive electrodes. In this paper, we demonstrated a water-bath assisted convective assembly process at the temporary water/alcohol interface for fabricating hierarchical aligned AgNW electrodes. The convection flow plays an important role during the assembly process. The assembled AgNW film fabricated via three times orthogonal dip-coating at a water-bath temperature of 80 °C has a sheet resistance of 11.4 Ω sq(-1) with 89.9% transmittance at 550 nm. Moreover, the root mean square (RMS) of this assembled AgNW film was only 15.6 nm which is much lower than the spin-coated random AgNW film (37.6 nm) with a similar sheet resistance. This facile assembly route provides a new way for manufacturing and tailoring ordered nanowire-based devices.

Strong metal oxide-zeolite interactions during selective catalytic reduction of nitrogen oxides.

In response to the stricter EU VII emission standards and the "150 â„ƒ challenge", selective catalytic reduction by ammonia (NH3-SCR) catalysts for motor vehicles are required to achieve high NO conversion below 200 °C. Compounding metal oxides with zeolites is an important strategy to design the low-temperature SCR catalysts. Here, we original prepared Cu-SSZ-13 @ MnGdOx (Cu-Z @ MGO), which achieved over 90% NO conversion and 95% N2 selectivity at 150 â„ƒ. It has been demonstrated that a uniform mesoporous loaded layer of MGO grows on Cu-Z, and a recrystallization zone appears at the MGO-Cu-Z interface. We discover that the excellent low-temperature SCR activity derives from the strong metal oxide-zeolite interaction (SMZI) effects. The SMZI effects cause the anchor and high dispersion of MGO on the surface of Cu-Z. Driven by the SMZI effects, the Mn3+/Mn4+ redox cycle ensures the low and medium temperature-SCR activity and the Cu2+/Cu+ redox cycle guarantees the medium and high temperature-SCR activity. The introduction of MGO improves the reaction activity of -NH2 species adsorbed at Mn sites at 150 â„ƒ, achieving a cycle of reduction and oxidation reactions at low temperatures. This strategy of inducing SMZI effects of metal oxides and zeolites paves a way for development of high-performance catalysts.

Incidence and radiological pattern of eosinophilic granuloma: a retrospective study in a Chinese tertiary hospital.

BACKGROUND: The incidence and radiological patterns of eosinophilic granuloma (EG) in China is not clear. We described the incidence, presentation, and imaging characteristics of Chinese EG patients in a tertiary hospital. METHODS: A retrospective chart review was performed from January 2004 to October 2017 at a single tertiary general hospital. Seventy-six patients were pathologically identified as EG. Besides, 60 patients with preoperative imaging diagnosis of "EG" were analyzed to reveal the radiological patterns and their diagnostic power. RESULTS: Fifty-three male and 23 female EG patients with a mean age of 18.1 ± 16.7 years (range 1-58 years) were retrospectively included. Significant differences were observed in gender (male to female = 2.3:1) and age (the highest incidence at the age of 0~5 years) for EG. EG predominantly involved the skeletal system: flat bones (31.43%) > irregular bones (24.76%) > long bones (22.86%) > other organs (20.95%). No obvious relationships between season, biochemical markers, and EG incidence were observed. The common presenting symptoms were pain followed with local mass, and most patients underwent surgical resection. Among 60 imagingly diagnosed "EG" patients from April 2009 to October 2017, only 22 were with histological confirmation. The correct diagnosis rates were 37.1% (13 out of 35), 16.7% (5 out of 30), and 22.2% (8 out of 36) for plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI), respectively. CONCLUSIONS: Chinese EG has a varied presentation, age distribution, and gender difference. EG diagnosis is still based on biopsy or histopathology instead of imaging techniques.

[Effects of paclitaxel and 5-fluorouracil on growth inhibition and apoptosis of hepatoma cells: a comparative study].

OBJECTIVE: To investigate the effect of paclitaxel and 5-flurouracil (5-Fu) on growth inhibition and apoptosis of human hepatoma BEL-7402 cells. METHODS: Growth inhibition of BEL-7402 cells treated with paclitaxel and 5-Fu, respectively, was measured by ATP-tumor chemosensitivity assay (ATP-TCA), and the cell cycle kinetics and apoptosis were analyzed by flow cytometry and microscopic examination. RESULTS: BEL-7402 cells were highly sensitive to paclitaxel with growth inhibition observed in both dose- and time-dependent manners (IC(50)=5.58 x 10(-7) mol/L). Paclitaxel induced significantly higher rate of cell apoptosis than the control group (P<0.05) but significantly lower rate than that induced by 5-Fu (P<0.01). Necrosis was observed predominantly in paclitaxel-treated cells whereas 5-Fu caused mainly cell apoptosis (P<0.05). Levels of apoptosis increased in proportion to the decrement of paclitaxel concentration but directly proportional to increment of 5-Fu concentration. CONCLUSIONS: Paclitaxel and 5-Fu are effective in inducing growth inhibition and apoptosis of BEL-7402 cells. While 5-Fu causes mainly apoptosis in hepatoma cells, the anticancer mechanism of paclitaxel is predominantly through induction of necrosis.