RESUMO
Volatile organic compounds (VOCs) play a major role in O3 formation in urban environments. However, the complexity in the emissions of VOCs and nitrogen oxides (NOx) in industrial cities has made it challenging to identify the key factors influencing O3 formation. This study used observation-based-model (OBM) to analyze O3 sensitivities to VOCs and NOx during summer in a typical industrial city in China. The OBM model results were coupled with a receptor model to analyze the sources of O3. Higher concentrations of O3 precursors were observed during polluted periods indicating that precursor accumulation contributed to the higher maxima of the net ozone formation rate and HOx concentrations. Analyses of ROx· budgets and relative incremental reactivity (RIR) indicated that O3 production is in a chemical transition regime and was sensitive to both VOCs and NOx. Results from Positive Matrix Factorization (PMF) analysis indicated that gasoline vehicle emissions, industrial processes, and coal combustion were major sources of O3 precursors. The sensitivities of O3 production to these sources depend on if both VOC and NOx sensitivities are considered. If only VOCs sensitivity is considered, in contrast, the contribution of anthropogenic sources to O3 production was significantly underestimated. This study highlights the importance of accounting for both VOCs and NOx sensitivities when O3 chemistry is in a transition regime in O3 production attribution studies.
RESUMO
Nanosized palladium (Pd)-based catalysts are widely used in the direct hydrogen peroxide (H2O2) synthesis from H2 and O2, while its selectivity and yield remain inferior because of the O-O bond cleavage from both the reactant O2 and the produced H2O2, which is assumed to have originated from various O2 adsorption configurations on the Pd nanoparticles. Herein, single Pd atom catalyst with high activity and selectivity is reported. Density functional theory calculations certify that the O-O bond breaking is significantly inhibited on the single Pd atom and the O2 is easier to be activated to form *OOH, which is a key intermediate for H2O2 synthesis; in addition, H2O2 degradation is shut down. Here, we show single Pd atom catalyst displays a remarkable H2O2 yield of 115 mol/gPd/h and H2O2 selectivity higher than 99%; while the concentration of H2O2 reaches 1.07 wt.% in a batch.
RESUMO
Diffuse large B-cell lymphoma (DLBCL) accounts for approximately 30% of the non-Hodgkin's lymphoma patients. The underlying molecular mechanism of its pathogenesis is not well defined and the survival rate of DLBCL patients is very low. Moreover, the annual incidence and mortality of DLBCL is still rising. Accordingly, identification and characterization of new molecular pathways of DLBCL will lead to the development of novel diagnostic markers and molecular therapeutic targets. Long non-coding RNAs (LncRNA) are non-coding RNAs with a length greater than 200 bp in eukaryotic cells, which can regulate the expression of their target genes at the transcriptional and post transcriptional levels. The function of LncRNAs is involved in the initiation, progression, invasion and metastasis of many cancers. Recently, the role of LncRNAs in DLBCL has been identified and intensely studied. This review summarizes the recent discoveries in the expression and function of LncRNAs including HULC,PEG10,LincRNA-p21,HOTAIR,LUNAR1,MALAT1 and SubSigLnc-17 in DLBCL, so as to find potential diagnostic biomarkers and therapeutic targets for DLBCL.