Iron–doped bismuth oxybromides as visible-light-responsive Fenton catalysts for the degradation of atrazine in aqueous phases

Pesticides and its degradation products,being well–known residues in soil,have recently been detected in many water bodies as pollutants of emerging concerns,and thus there is a contemporary demand to develop viable and cost–effective techniques for the removal of related organic pollutants in aqueous phases.Herein,a visible-light-responsive Fenton system was constructed with iron–doped bismuth oxybromides(Fe–BiOBr)as the catalysts.Taking the advantage of sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion and optimized H_(2)O_(2)utilization,the optimal Fe–BiOBr–2 catalyst showed an excellent atrazine removal efficiency of 97.61%in 120 min,which is superior than the traditional homogeneous Fenton and the majority of heterogeneous processes documented in the literature.In this photo–Fenton system,hydroxyl(·OH)and superoxide(·O_(2)^(-))radicals were dominant active species contributed to the oxidative degradation of atrazine.Due to the production of various active radicals,five degradation pathways were proposed based on the identification of intermediates and degradation products.Overall,this work not only demonstrates a fundamental insight into creating highly efficient and atom economic photo-Fenton systems,but also provides a complementary strategy for the treatment of organic pollutants in water.

Simulation of stray grain formation in Ni-base single crystal turbine blades fabricated by HRS and LMC techniques

The simulation models of the thermal and macrostructural evolutions during directional solidification of Ni-base single crystal(SX) turbine blades under high rate solidification(HRS) and liquid metal cooling(LMC) have been constructed using Pro CAST software, coupled with a 3D Cellular Automaton Finite Element(CAFE) model. The models were used to investigate the tendencies of stray grain(SG) formation in the platform region of turbine blades fabricated by HRS and LMC techniques. The results reveal that the LMC technique can prohibit SG formation by smoothing the concaved isotherm and in turn alleviating the undercooling in the platform ends to let the dendrites fill up the undercooled zone before SG nucleation. The simulation results agreed well with the experimental results, indicating that these models could be used to analyze the macrostructural evolution or to optimize process parameters to suppress SG formation. Using these models, the critical withdrawal rate for casting SX turbine blades without SG formation were determined to be around 75 μm·s^(-1) and 100 μm·s^(-1) for HRS and LMC respectively, suggesting that LMC can be used as an efficient technique in fabricating SX turbine blades without any SG defect formation.

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment technologies.Herein,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton processes.Due to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical analyses.This work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

Photocatalytic CO_(2)-to-Ethylene Conversion over Bi_(2)S_(3)/CdS Heterostructures Constructed via Facile Cation Exchange

Solar-driven CO_(2)conversion to multicarbon(C_(2+))products has emerged as a key challenge,yet this calls for a systematic investigation on the overall reaction process and mechanism at an atomic level based on the rational design of highly selective photocatalysts.Herein,we report the synthesis of compact Bi_(2)S_(3)/Cds heterostructures via facile cation exchange,by which a unique pathway of CO_(2)-to-C_(2)H_(4) photoconversion is achieved.Specifically,the BCS-30 shows an optimal C_(2)H_(4) production rate of 3.49μmolh^(-1)g^(-1) based on the regulation of band structures and energy levels of photocatalysts by controlled growth of Bi_(2)S_(3) at CdS surface.Both experimental and theoretical results(DFT calculations)identify Bi atoms as new catalytic sites for the adsorption of CO*and formation of*CO-*CO dimers that further hydrogenate to produce ethylene.Overall,this work demonstrates vast potentials of delicately designed heterostructures for CO_(2) conversion towards C_(2+)products under mild photocatalytic conditions.

MicroRNA-21 in the pathogenesis of acute kidney injury

Acute kidney injury(AKI),associated with significant mor-bidity and mortality,is widely known to involve epithelial apoptosis,excessive inflammation,and fibrosis in re-sponse to ischemia or reperfusion injury,which results in either chronic pathological changes or death.Therefore,it is imperative that investigations are conducted in order to fi nd effective,early diagnoses,and therapeutic targets needed to help prevent and treat AKI.However,the mech-anisms modulating the pathogenesis of AKI still remain largely undetermined.MicroRNAs(miRNAs),small non-coding RNA molecules,play an important role in several fundamental biological and pathological processes by a post transcriptional regulatory function of gene expres-sion.MicroRNA-21(miR-21)is a recently identifi ed,typi-cal miRNA that is functional as a regulator known to be involved in apoptosis as well as inflammatory and fi brotic signaling pathways in AKI.As a result,miR-21 is now considered a novel biomarker when diagnosing and treat-ing AKI.This article reviews the correlative literature and research progress regarding the roles of miR-21 in AKI.

Impacts of temperatures and phosphoric-acid modification to the physicochemical properties of biochar for excellent sulfadiazine adsorption

The textural properties and surface chemistry of phosphoric acid-modified biochars(PABCs)prepared at different pyrolysis temperatures(500-700℃)were studied based on the results obtained from XRD,SEM,BET,FT-IR,Raman,XPS and elements analyses.PABCs prepared at higher temperatures tended to possess a bigger proportion of microporous structure.The adsorption capacity and initial rate of PABCs for sulfadiazine(SDZ)were notably improved to 139.2 mg/g and 9.66 mg/(g min)as calculated from the Langmuir model.The adsorption equilibrium time was only one quarter of that without modification.The H_(3)PO_(4) modification was advantageous to produce phosphate and break functional groups to form disordered carbon structure abundant of micropores.The enhancement in the adsorption of SDZ was due to the confinement effect of hydrophobic cavities from the mircoporous structure and theπ-πelectron-donor-acceptor interaction.Specially,PABCs exhibited stable adsorption capacities at a wide pH range(3.0-9.0)or relatively high concentrations of coexisting ions.

Association between TaqIB polymorphism of cholesteryl ester transfer protein and coronary artery disease in the Chinese population

Objective: To assess whether the TaqIB polymorphism of cholesteryl ester transfer protein (CETP) is associated with coronary artery disease (CAD) in Chinese population, we performed a meta-analysis in this paper. Methods: We searched PubMed, Embase, the Science Citation Index (SCI), the China Biological Medicine database (CBM), the China National Knowledge Infrastructure (CNKI), and the Wanfang database for relevant articles. Data were extracted, and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Results: The lit- erature search yielded 448 studies, in which 10 case-control studies including 1 694 cases and 1 456 controls matched the selection criteria. The combined B1 and B2 allele frequencies were 0.587 and 0.413, respectively. The pooled OR was 1.10 (95% CI, 0.89-1.34) for comparing the B1B1 or B1B2 carriers with B2B2 carriers, and was 1.27 (95% CI, 1.09-1.49) in the B1B1 carriers versus B2B2 or B1B2 carriers. Conclusions: In the present study, the TaqIB poly- morphism of CETP was found to be associated with CAD in the Chinese population.