15 research outputs found

    Nitric oxide and nitrous oxide emissions from a full-scale activated sludge anaerobic/anoxic/oxic process

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    Both nitric oxide (NO) and nitrous oxide (NO) have strong negative effects on the environment. Although NO emissions in wastewater water treatment plants (WWTPs) have been widely studied, the concurrence of NO and NO emissions has not been well characterized, and their emission status from WWTPs in China is still not clear. In this study, online NO and NO analyzers were used to investigate spatial and temporal variations of NO and NO emissions in a full-scale activated sludge anaerobic/anoxic/oxic (A/O) process over one year. The amoA gene of ammonia oxidation bacteria and the nosZ gene of denitrifiers were analyzed to identify possible NO and NO production pathways. The emission factors of NO and NO in the studied A/O process were 0.01±0.006% (0.002-0.021%) and 1.29±1.07% (0.095-3.44%) of the nitrogen load, respectively. Both NO and NO were mainly emitted from the oxic zone, with emitting levels increasing greatly from the initial oxic zone to the zone end. The NO emission pattern closely resembled that of NO emissions, but the emission amounts were 2-3 magnitudes higher than that of NO. Nitrite accumulation directly triggered NO and NO production. This study provides novel insights into emission characteristics and the production pathways of both NO and NO from a full-scale A/O process, which is of great significance toward development of effective mitigation strategies for NO and NO emissions from WWTPs

    A 2 ÎĽm Dual-Wavelength Laser at Cryogenic Temperature with Balanced Simultaneous Emission

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    A Tm,Ho:YAP laser at cryogenic temperature is demonstrated for the first time with simultaneous emission at 2000 nm and 2119 nm. The feasibility of switching wavelength and achieving balanced output powers at two widely separated wavelengths has been confirmed by investigating the temperature dependence of the laser spectra. The optimal temperature for balanced output evidently diminishes as the pump power density increases, thereby manifesting a rate of change quantified at 1.19 K/W. At the optimal temperature of 43.1 K, the optical-to-optical conversion efficiency of the Tm,Ho:YAP simultaneous dual-wavelength laser (SDWL) with a pump power of 11.8 W is 12.7%, corresponding to a slope efficiency of 15.8%

    Influencing Factors of Shear Wave Radiation of a Dipole Source in a Fluid-Filled Borehole

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    In shear wave far detection logging, dipole-source radiation is the main factor influencing the amplitude of the reflected shear waves. In this paper, a method is derived with the far-field asymptotic solution to calculate the dipole-source radiation of shear waves in a fluid-filled borehole. Then the dipole-source radiation of the shear waves is simulated under both low and high frequencies. In addition, the influences of formation elastic parameters on the dipole-source radiation of the shear waves are analyzed and the variations of the radiation characteristics of the shear wave with source main frequency and borehole radius are compared. Results show that the density and compressional wave velocity of the formation have little effect on the dipole-source radiation of the shear waves. However, the shear wave velocity not only affects the shear wave amplitude radiated to the formation by the dipole source (radiation performance), but also affects the energy distribution of the shear wave at different locations in space (radiation direction). The dipole source has better radiation performance and radiation coverage at low frequency and the optimal excitation frequency in different formations is very close, which is good for the application of this technology under different circumstances. At low frequency, the borehole has little influence on the dipole-source radiation, no matter how large the borehole radius is. However, at high frequency, the borehole modulation of the dipole-source radiation cannot be ignored, especially at large borehole radius

    Data_Sheet_1_The alleviative effect of Calendula officinalis L. extract against Parkinson’s disease-like pathology in zebrafish via the involvement of autophagy activation.docx

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    IntroductionParkinson’s disease (PD) is the second most prevalent neurodegenerative disorder. However, effective preventative or therapeutic agents for PD remain largely limited. Marigold Calendula officinalis L. (CoL) has been reported to possess a wide range of biological activities, but its neuroprotective activity including anti-neurodegenerative diseases is unclear. Here, we aim to investigate whether the extract of CoL (ECoL) has therapeutic activity on PD.MethodsWe identified the chemical composition of flavonoid, an important active ingredient in ECoL, by a targeted HPLC-Q-TOF-MS analysis. Subsequently, we evaluated the anti-PD effect of ECoL by using zebrafish PD model induced by 1-methyl-4-phenyl-1-1,2,3,6-tetrahydropyridine (MPTP). After ECoL+MPTP co-treatments, the changes of dopaminergic neurons, neural vasculature, nervous system, and locomotor activity were examined, respectively. The expressions of genes related to neurodevelopment and autophagy were detected by RT-qPCR. Further, the interaction between autophagy regulators and ECoL flavonoids was predicted using molecular docking method.ResultsAs a result, 5 kinds of flavonoid were identified in ECoL, consisting of 121 flavones and flavonols, 32 flavanones, 22 isoflavonoids, 11 chalcones and dihydrochalcones, and 17 anthocyanins. ECoL significantly ameliorated the loss of dopaminergic neurons and neural vasculature, restored the injury of nervous system, and remarkably reversed the abnormal expressions of neurodevelopment-related genes. Besides, ECoL notably inhibited the locomotor impairment in MPTP-induced PD-like zebrafish. The underlying anti-PD effect of ECoL may be implicated in activating autophagy, as ECoL significantly upregulated the expressions of genes related to autophagy, which contributes to the degradation of α-synuclein aggregation and dysfunctional mitochondria. Molecular docking simulation showed the stable interaction between autophagy regulators (Pink, Ulk2, Atg7, and Lc3b) and 10 main compounds of flavonoid in ECoL, further affirming the involvement of autophagy activation by ECoL in anti-PD action.ConclusionOur results suggested that ECoL has the anti-PD effect, and ECoL might be a promising therapeutic candidate for PD treatment.</p

    A spongy nickel-organic CO2 reduction photocatalyst for nearly 100% selective CO production.

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    Solar-driven photocatalytic conversion of CO2 into fuels has attracted a lot of interest; however, developing active catalysts that can selectively convert CO2 to fuels with desirable reaction products remains a grand challenge. For instance, complete suppression of the competing H2 evolution during photocatalytic CO2-to-CO conversion has not been achieved before. We design and synthesize a spongy nickel-organic heterogeneous photocatalyst via a photochemical route. The catalyst has a crystalline network architecture with a high concentration of defects. It is highly active in converting CO2 to CO, with a production rate of ~1.6 Ă— 104 ÎĽmol hour-1 g-1. No measurable H2 is generated during the reaction, leading to nearly 100% selective CO production over H2 evolution. When the spongy Ni-organic catalyst is enriched with Rh or Ag nanocrystals, the controlled photocatalytic CO2 reduction reactions generate formic acid and acetic acid. Achieving such a spongy nickel-organic photocatalyst is a critical step toward practical production of high-value multicarbon fuels using solar energy
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