Oxygen-Assisted Supercapacitive Swing Adsorption of Carbon Dioxide.

We report on the supercapacitive swing adsorption (SSA) of carbon dioxide at different voltage windows in the presence of oxygen using activated carbon electrodes, and deliquescent, aqueous electrolytes. The presence of O2 in the CO2/N2 gas mixture results in an up to 11 times higher CO2 adsorption capacity with 3M MgBr2 (at 0.6V) and up to 4-5 times higher adsorption capacity with 3M MgCl2 (at 1V). A tradeoff between high CO2 adsorption capacities and lower coulombic efficiencies was observed at voltages above 0.6V. The energetic and adsorptive performance of the electrodes in the presence of oxygen below 0.5V was similar to the performance with a CO2/N2 mixture without oxygen at 1V. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of the electrodes demonstrate that the specific capacitance increases while the diffusion resistance decreases in the presence of oxygen. Oxygen concentrations ranging between 5-20% give similar energetic and adsorptive performance. The electrodes exhibit stable performance for up to 100 cycles of operation.

Assignment of Vibrational Bands of Critical Surface Species Containing Nitrogen in the Selective Catalytic Reduction of NO by NH3.

The selective catalytic reduction (SCR) of NO by NH3 on metal oxides plays a key role in minimizing NOx emissions. Electronic structure calculations at the density functional theory level have been performed to predict the vibrational modes of NH3/NH4+ bound to validated cluster models of vanadium oxide bound to a TiO2 surface. Excellent agreement of the scaled calculated values with the observed bands attributed to surface-bound species is found. The presence of NH3 bound to Lewis acid sites and NH4+ bound to Brønsted acid sites when VOH groups are present is supported by our predictions. NH4+ is expected to dominate the spectra even at low concentrations, with predicted intensities 5 to 30 times greater than those predicted for surface-bound NH3. This is particularly evident in the lowest-energy N-H stretches of surface NH4+ due to partial proton transfer interactions with the vanadium oxide surface model. The current work is consistent with experimental vibrational spectroscopy results and does not support the presence of a significant amount of NH2 on the catalyst surface for the SCR reaction on VOx/TiO2. The combined experimental and computational results support the presence of both NH3- and NH4+-type species bound to the surface.

Methane activation by ZSM-5-supported transition metal centers.

This review focuses on recent fundamental insights about methane dehydroaromatization (MDA) to benzene over ZSM-5-supported transition metal oxide-based catalysts (MOx/ZSM-5, where M = V, Cr, Mo, W, Re, Fe). Benzene is an important organic intermediate, used for the synthesis of chemicals like ethylbenzene, cumene, cyclohexane, nitrobenzene and alkylbenzene. Current production of benzene is primarily from crude oil processing, but due to the abundant availability of natural gas, there is much recent interest in developing direct processes to convert CH4 to liquid chemicals. Among the various gas-to-liquid methods, the thermodynamically-limited Methane DehydroAromatization (MDA) to benzene under non-oxidative conditions appears very promising as it circumvents deep oxidation of CH4 to CO2 and does not require the use of a co-reactant. The findings from the MDA catalysis literature is critically analyzed with emphasis on in situ and operando spectroscopic characterization to understand the molecular level details regarding the catalytic sites before and during the MDA reaction. Specifically, this review discusses the anchoring sites of the supported MOx species on the ZSM-5 support, molecular structures of the initial dispersed surface MOx sites, nature of the active sites during MDA, reaction mechanisms, rate-determining step, kinetics and catalyst activity of the MDA reaction. Finally, suggestions are given regarding future experimental investigations to fill the information gaps currently found in the literature.

Design, assembly and validation of a low-cost, high-fidelity simulator for heart exploration.

INTRODUCTION: Heart exploration is an essential clinical competence that requires continuous training and exposure. Low availability and accessibility to patients with heart disease constitutes a barrier to acquiring this competence. Inadequate cardiac auscultation skills in medical students, residents, and graduate physicians have been documented. OBJECTIVE: To develop and validate a low-cost, high-fidelity simulator for heart exploration. METHODS: A low-cost, high-fidelity heart examination simulator capable of reproducing normal cardiac sounds was designed and developed. Subsequently, the simulator was validated by a group of experts who gave their opinion according to a Likert scale. RESULTS: Ninety-four percent agreed that the simulator motivates the learning of heart exploration, and 92 % considered it to be a realistic model; 91 % considered that the simulator is an attractive tool to reinforce learning and 98 % recommended its further use. CONCLUSIONS: The use of the simulator facilitates the acquisition of skills and stimulates learning in the student, which can be attributed to repeated practice, longer exposure time and cognitive interaction.

INTRODUCCIÓN: La exploración cardiaca es una competencia clínica fundamental que requiere exposición o entrenamiento continuo. La baja disponibilidad y accesibilidad de pacientes con patología cardiaca constituye una barrera para adquirir esta competencia. Se han documentado inadecuadas habilidades de auscultación cardiaca en estudiantes de medicina, residentes y médicos graduados. OBJETIVO: Elaborar y validar un simulador de alta fidelidad y bajo costo para exploración cardiaca. MÉTODOS: Se diseñó y elaboró un simulador para exploración cardiaca, realista y de bajo costo capaz de reproducir ruidos cardiacos normales. Posteriormente se realizó la validación del simulador por un grupo de expertos que emitieron su opinión de acuerdo con una escala tipo Likert. RESULTADOS: El 94 % afirmó que el simulador motiva el aprendizaje de la exploración cardiaca y 92 % lo consideró un modelo realista; 91 % consideró que el simulador es una herramienta atractiva para fortalecer el aprendizaje y 98 % recomendó seguir utilizándolo. CONCLUSIONES: El uso del simulador facilita la adquisición de competencias y estimula el aprendizaje en el estudiante, lo cual puede ser atribuido a la práctica deliberada, a un mayor tiempo de exposición y a la interacción cognitiva.

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na2 WO4 /SiO2 Catalysts.

The complex structure of the catalytic active phase, and surface-gas reaction networks have hindered understanding of the oxidative coupling of methane (OCM) reaction mechanism by supported Na2 WO4 /SiO2 catalysts. The present study demonstrates, with the aid of in situ Raman spectroscopy and chemical probe (H2 -TPR, TAP and steady-state kinetics) experiments, that the long speculated crystalline Na2 WO4 active phase is unstable and melts under OCM reaction conditions, partially transforming to thermally stable surface Na-WOx sites. Kinetic analysis via temporal analysis of products (TAP) and steady-state OCM reaction studies demonstrate that (i) surface Na-WOx sites are responsible for selectively activating CH4 to C2 Hx and over-oxidizing CHy to CO and (ii) molten Na2 WO4 phase is mainly responsible for over-oxidation of CH4 to CO2 and also assists in oxidative dehydrogenation of C2 H6 to C2 H4 . These new insights reveal the nature of catalytic active sites and resolve the OCM reaction mechanism over supported Na2 WO4 /SiO2 catalysts.

Elucidation of the Reaction Mechanism for High-Temperature Water Gas Shift over an Industrial-Type Copper-Chromium-Iron Oxide Catalyst.

The water gas shift (WGS) reaction is of paramount importance for the chemical industry, as it constitutes, coupled with methane reforming, the main industrial route to produce hydrogen. Copper-chromium-iron oxide-based catalysts have been widely used for the high-temperature WGS reaction industrially. The WGS reaction mechanism by the CuCrFeO x catalyst has been debated for years, mainly between a "redox" mechanism involving the participation of atomic oxygen from the catalyst and an "associative" mechanism proceeding via a surface formate-like intermediate. In the present work, advanced in situ characterization techniques (infrared spectroscopy, temperature-programmed surface reaction (TPSR), near-ambient pressure XPS (NAP-XPS), and inelastic neutron scattering (INS)) were applied to determine the nature of the catalyst surface and identify surface intermediate species under WGS reaction conditions. The surface of the CuCrFeO x catalyst is found to be dynamic and becomes partially reduced under WGS reaction conditions, forming metallic Cu nanoparticles on Fe3O4. Neither in situ IR not INS spectroscopy detect the presence of surface formate species during WGS. TPSR experiments demonstrate that the evolution of CO2 and H2 from the CO/H2O reactants follows different kinetics than the evolution of CO2 and H2 from HCOOH decomposition (molecule mimicking the associative mechanism). Steady-state isotopic transient kinetic analysis (SSITKA) (CO + H216O → CO + H218O) exhibited significant 16O/18O scrambling, characteristic of a redox mechanism. Computed activation energies for elementary steps for the redox and associative mechanism by density functional theory (DFT) simulations indicate that the redox mechanism is favored over the associative mechanism. The combined spectroscopic, computational, and kinetic evidence in the present study finally resolves the WGS reaction mechanism on the industrial-type high-temperature CuCrFeO x catalyst that is shown to proceed via the redox mechanism.

Enterocutaneous Fistula Coexisting with Enterovesical Fistula: A Rare Complication of Ovarian Cystectomy.

Enterocutaneous fistula is an abnormal communication between the intestine and the skin, while enterovesical fistula is an abnormal communication between the intestine and the bladder. Both are not usual complications of ovarian cystectomy. We present a patient with enterovesical fistula coexisting with enterocutaneous fistula following ovarian cystectomy. She is a 24- year-old lady with background immunosupression who presented to the National Obstetric Fistula Centre, Abakaliki South-East Nigeria with a history fecaluria, pneumaturia and passage of feculent fluid through the skin following ovarian cystectomy. Fistulogram was in keeping with rectovesical fistula. She was repaired in a single stage and made an uneventful recovery. Enterovesical fistula and enterocutaneus fistula are uncommon but possible complications of ovarian cystectomy.

Strong Metal-Support Interactions between Copper and Iron Oxide during the High-Temperature Water-Gas Shift Reaction.

The commercial high-temperature water-gas shift (HT-WGS) catalyst consists of CuO-Cr2 O3 -Fe2 O3 , where Cu functions as a chemical promoter to increase the catalytic activity, but its promotion mechanism is poorly understood. In this work, a series of iron-based model catalysts were investigated with in situ or pseudo in situ characterization, steady-state WGS reaction, and density function theory (DFT) calculations. For the first time, a strong metal-support interaction (SMSI) between Cu and FeOx was directly observed. During the WGS reaction, a thin FeOx overlayer migrates onto the metallic Cu particles, creating a hybrid surface structure with Cu-FeOx interfaces. The synergistic interaction between Cu and FeOx not only stabilizes the Cu clusters, but also provides new catalytic active sites that facilitate CO adsorption, H2 O dissociation, and WGS reaction. These new fundamental insights can potentially guide the rational design of improved iron-based HT-WGS catalysts.

Mechanism by which Tungsten Oxide Promotes the Activity of Supported V2 O5 /TiO2 Catalysts for NOX Abatement: Structural Effects Revealed by 51 V MAS NMR Spectroscopy.

The selective catalytic reduction (SCR) of NOx with NH3 to N2 with supported V2 O5 (-WO3 )/TiO2 catalysts is an industrial technology used to mitigate toxic emissions. Long-standing uncertainties in the molecular structures of surface vanadia are clarified, whereby progressive addition of vanadia to TiO2 forms oligomeric vanadia structures and reveals a proportional relationship of SCR reaction rate to [surface VOx concentration]2 , implying a 2-site mechanism. Unreactive surface tungsta (WO3 ) also promote the formation of oligomeric vanadia (V2 O5 ) sites, showing that promoter incorporation enhances the SCR reaction by a structural effect generating adjacent surface sites and not from electronic effects as previously proposed. The findings outline a method to assess structural effects of promoter incorporation on catalysts and reveal both the dual-site requirement for the SCR reaction and the important structural promotional effect that tungsten oxide offers for the SCR reaction by V2 O5 /TiO2 catalysts.

Nature of Active Sites and Surface Intermediates during SCR of NO with NH3 by Supported V2O5--WO3/TiO2 Catalysts.

Time-resolved in situ IR was performed during selective catalytic reduction of NO with NH3 on supported V2O5-WO3/TiO2 catalysts to examine the distribution and reactivity of surface ammonia species on Lewis and Brønsted acid sites. While both species were found to participate in the SCR reaction, their relative population depends on the coverage of the surface vanadia and tungsta sites, temperature, and moisture. Although the more abundant surface NH4+,ads intermediates dominate the overall SCR reaction, especially for hydrothermally aged catalysts, the minority surface NH3,ads intermediates exhibit a higher specific SCR activity (TOF). The current study serves to resolve the long-standing controversy about the active sites for SCR of NO with NH3 by supported V2O5-WO3/TiO2 catalysts.

Pharmacodynamic genome-wide association study identifies new responsive loci for glucocorticoid intervention in asthma.

Asthma is a chronic lung disease that has a high prevalence. The therapeutic intervention of this disease can be made more effective if genetic variability in patients' response to medications is implemented. However, a clear picture of the genetic architecture of asthma intervention response remains elusive. We conducted a genome-wide association study (GWAS) to identify drug response-associated genes for asthma, in which 909 622 SNPs were genotyped for 120 randomized participants who inhaled multiple doses of glucocorticoids. By integrating pharmacodynamic properties of drug reactions, we implemented a mechanistic model to analyze the GWAS data, enhancing the scope of inference about the genetic architecture of asthma intervention. Our pharmacodynamic model observed associations of genome-wide significance between dose-dependent response to inhaled glucocorticoids (measured as %FEV1) and five loci (P=5.315 × 10(-7) to 3.924 × 10(-9)), many of which map to metabolic genes related to lung function and asthma risk. All significant SNPs detected indicate a recessive effect, at which the homozygotes for the mutant alleles drive variability in %FEV1. Significant associations were well replicated in three additional independent GWAS studies. Pooled together over these three trials, two SNPs, chr6 rs6924808 and chr11 rs1353649, display an increased significance level (P=6.661 × 10(-16) and 5.670 × 10(-11)). Our study reveals a general picture of pharmacogenomic control for asthma intervention. The results obtained help to tailor an optimal dose for individual patients to treat asthma based on their genetic makeup.

Morbidity and mortality after major pulmonary resections in patients with locally advanced stage IIIA non-small cell lung carcinoma who underwent induction therapy.

BACKGROUND: The optimal treatment for patients with locally advanced stage IIIA non-small cell lung carcinoma (NSCLC) remains controversial, but induction therapy is increasingly used. The aim of this study was to evaluate mortality, morbidity, hospital stay and frequency of postoperative complications in stage IIIA NSCLC patients that underwent major pulmonary resections after neoadjuvant chemotherapy or chemoradiation. METHODS: We conducted a retrospective analysis of all patients who underwent major pulmonary resections after induction therapy for locally advanced NSCLC from October 2009 to February 2014. Forty-one patients were included in the study. RESULTS: Complete resection was achieved in 40 patients (97.5%). A complete pathologic response was seen in 10 patients (24.4%). Mean hospital stay was 17.7 days (ranged 5-129 days). Early (in-hospital) mortality occurred in 2.4% (one patient after bilobectomy), late (six months) mortality in 4.9% (two patients after right pneumonectomy and bilobectomy), and overall morbidity in 58.5% (24 patients). Postoperative complications included: bronchopleural fistula (BPF) with empyema - three patients, empyema without BPF - five patients, air leak - eight patients, atrial fibrillation - eight patients, pneumonia - eight patients, and lobar atelectasis - four patients. CONCLUSION: Following neoadjuvant therapy for stage IIIA NSCLC, pneumonectomy can be performed with low early and late mortality (0% and 5.8%, respectively), bilobectomy is a high risk operation (16.7% early and 16.7% late mortality); and lobectomy a low risk operation (0% early and late mortality). The need for major pulmonary resections should not be a reason to exclude patients from a potentially curative procedure if it can be performed with acceptable morbidity and mortality rates at an experienced medical centre.

Revealing the Nature of Active Oxygen Species and Reaction Mechanism of Ethylene Epoxidation by Supported Ag/α-Al2O3 Catalysts.

The oxygen species on Ag catalysts and reaction mechanisms for ethylene epoxidation and ethylene combustion continue to be debated in the literature despite decades of investigation. Fundamental details of ethylene oxidation by supported Ag/α-Al2O3 catalysts were revealed with the application of high-angle annular dark-field-scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (HAADF-STEM-EDS), in situ techniques (Raman, UV-vis, X-ray diffraction (XRD), HS-LEIS), chemical probes (C2H4-TPSR and C2H4 + O2-TPSR), and steady-state ethylene oxidation and SSITKA (16O2 → 18O2 switch) studies. The Ag nanoparticles are found to carry a considerable amount of oxygen after the reaction. Density functional theory (DFT) calculations indicate the oxidative reconstructed p(4 × 4)-O-Ag(111) surface is stable relative to metallic Ag(111) under the relevant reaction environment. Multiple configurations of reactive oxygen species are present, and their relevant concentrations depend on treatment conditions. Selective ethylene oxidation to EO proceeds with surface Ag4-O2* species (dioxygen species occupying an oxygen site on a p(4 × 4)-O-Ag(111) surface) only present after strong oxidation of Ag. These experimental findings are strongly supported by the associated DFT calculations. Ethylene epoxidation proceeds via a Langmuir-Hinshelwood mechanism, and ethylene combustion proceeds via combined Langmuir-Hinshelwood (predominant) and Mars-van Krevelen (minor) mechanisms.

Plasma-assisted manipulation of vanadia nanoclusters for efficient selective catalytic reduction of NOx.

Supported nanoclusters (SNCs) with distinct geometric and electronic structures have garnered significant attention in the field of heterogeneous catalysis. However, their directed synthesis remains a challenge due to limited efficient approaches. This study presents a plasma-assisted treatment strategy to achieve supported metal oxide nanoclusters from a rapid transformation of monomeric dispersed metal oxides. As a case study, oligomeric vanadia-dominated surface sites were derived from the classic supported V2O5-WO3/TiO2 (VWT) catalyst and showed nearly an order of magnitude increase in turnover frequency (TOF) value via an H2-plasma treatment for selective catalytic reduction of NO with NH3. Such oligomeric surface VOx sites were not only successfully observed and firstly distinguished from WOx and TiO2 by advanced electron microscopy, but also facilitated the generation of surface amide and nitrates intermediates that enable barrier-less steps in the SCR reaction as observed by modulation excitation spectroscopy technologies and predicted DFT calculations.

Rhythmic profiles of cell cycle and circadian clock gene transcripts in mice: a possible association between two periodic systems.

The circadian system shapes the rhythms of most biological functions. The regulation of the cell cycle by a circadian clock was suggested to operate via stages S, G2 and G2/M. This study investigated a possible time link at stages G1 and G1/S as well. The daily expression profiles of cell cycle markers (Ccnd1, Ccne1 and Pcna) and circadian clock genes (Per2 and Clock) were monitored in liver and esophagus (low and high proliferation index, respectively) of BALB/c mice. Locomotor activity displayed a 24 h rhythm, establishing the circadian organization of the suprachiasmatic nucleus. In the liver, the mRNA level of Per2 and Clock fitted the circadian rhythm with a 7.5 h shift. This temporal pattern suggests that the liver harbors a functional circadian clock. The rhythm of the analyzed cell cycle genes, however, was of low significance fitness and showed an opposite peak time between Pcna and Clock. These results indicate a weak regulatory role of the circadian clock. In the esophagus, the rhythms of Clock and Per2 mRNA had a similar peak time and non-circadian periods. These results suggest either that the esophagus does not harbor a functional circadian apparatus or that the phenotypes stem from differences in phase and amplitude of the rhythms of its various cell types. The similarity in the rhythm parameters of Clock, Ccne1 and Pcna transcripts questions the control of the circadian clock on the cell cycle along the G1 and G1/S stages. Yet the G1/S transition may play a role in modulating the local clock of proliferating tissues.

Pharmacogenetic association between ALOX5 promoter genotype and the response to anti-asthma treatment.

Clinically similar asthma patients may develop airway obstruction by different mechanisms. Asthma treatments that specifically interfere with the 5-lipoxygenase (ALOX5) pathway provide a method to identify those patients in whom the products of the ALOX5 pathway (that is, the leukotrienes) contribute to the expression of the asthma phenotype. Failure of an asthma patient to respond to treatment with ALOX5-pathway modifiers indicates that leukotrienes are not critical to the expression of the asthmatic phenotype in that patient. We previously defined a family of DNA sequence variants in the core promoter of the gene ALOX5 (on chromosome 10q11.2) associated with diminished promoter-reporter activity in tissue culture. Because expression of ALOX5 is in part transcriptionally regulated, we reasoned that patients with these sequence variants may have diminished gene transcription, and therefore decreased ALOX5 product production and a diminished clinical response to treatment with a drug targeting this pathway. Such an effect indicates an interaction between gene promoter sequence variants and drug-treatment responses, that is, a pharmacogenetic effect of a promoter sequence on treatment responses.

Endobronchial closure of recurrent bronchopleural and tracheopleural fistulae by two amplatzer devices.

We present a case of right pneumonectomy after induction chemotherapy complicated by a large bronchopleural fistula and empyema two weeks after surgery. The patient was treated surgically by transsternal transpericardial bronchopleural fistula closure and open window thoracoplasty. Thereafter, two new fistulae developed, one in the right main bronchial stump and one in the accessory tracheal bronchus. The two Amplatzer devices that were originally designed for transcatheter closure of cardiac defects were successfully used for closure of the bronchopleural fistulae.

How strain affects the reactivity of surface metal oxide catalysts.

Highly dispersed molybdenum oxide supported on mesoporous silica SBA-15 has been prepared by anion exchange resulting in a series of catalysts with changing Mo densities (0.2-2.5 Mo atoms nm(-2) ). X-ray absorption, UV/Vis, Raman, and IR spectroscopy indicate that doubly anchored tetrahedral dioxo MoO4 units are the major surface species at all loadings. Higher reducibility at loadings close to the monolayer measured by temperature-programmed reduction and a steep increase in the catalytic activity observed in metathesis of propene and oxidative dehydrogenation of propane at 8 % of Mo loading are attributed to frustration of Mo oxide surface species and lateral interactions. Based on DFT calculations, NEXAFS spectra at the O-K-edge at high Mo loadings are explained by distorted MoO4 complexes. Limited availability of anchor silanol groups at high loadings forces the MoO4 groups to form more strained configurations. The occurrence of strain is linked to the increase in reactivity.

Influence of 2'-Modifications (O-Methylation, Fluorination, and Stereochemical Inversion) on the Base Pairing Energies of Protonated Cytidine Nucleoside Analogue Base Pairs: Implications for the Stabilities of i-Motif Structures.

Naturally occurring and chemically engineered modifications are among the most powerful strategies explored for fine-tuning the conformational characteristics and intrinsic stability of nucleic acids topologies. Modifications at the 2'-position of the ribose or 2'-deoxyribose moieties differentiate nucleic acid structures and have a significant impact on their electronic properties and base-pairing interactions. 2'-O-Methylation, a common post-transcriptional modification of tRNA, is directly involved in modulating specific anticodon-codon base-pairing interactions. 2'-Fluorinated and arabino nucleosides possess novel and beneficial medicinal properties and find use as therapeutics for treating viral diseases and cancer. However, the potential to deploy 2'-modified cytidine chemistries for tuning i-motif stability is largely unknown. To address this knowledge gap, the effects of 2'-modifications including O-methylation, fluorination, and stereochemical inversion on the base-pairing interactions of protonated cytidine nucleoside analogue base pairs, the core stabilizing interactions of i-motif structures, are examined using complementary threshold collision-induced dissociation techniques and computational methods. The 2'-modified cytidine nucleoside analogues investigated here include 2'-O-methylcytidine, 2'-fluoro-2'-deoxycytidine, arabinofuranosylcytosine, 2'-fluoro-arabinofuranosylcytosine, and 2',2'-difluoro-2'-deoxycytidine. All five 2'-modifications examined here are found to enhance the base-pairing interactions relative to the canonical DNA and RNA cytidine nucleosides with the greatest enhancements arising from 2'-O-methylation and 2',2'-difluorination, suggesting that these modifications should well be tolerated in the narrow grooves of i-motif conformations.

Design of Cr-Free Promoted Copper-Iron Oxide-Based High-Temperature Water-Gas Shift Catalysts.

The effect of Ce addition to the Cr-free Al-promoted Cu-Fe oxide-based catalysts is investigated. Catalyst characterization (X-ray diffraction (XRD), in situ Raman spectroscopy, high-sensitivity low-energy ion scattering (HS-LEIS), Brunauer-Emmett-Teller (BET) analysis), CO-temperature-programmed reduction chemical probing, and steady-state WGS activity reveal that (i) in the absence of Al, Ce addition via coprecipitation has a detrimental effect on the catalytic activity related to the poor thermostability and formation of less active Ce-Cu-O NPs, (ii) the addition of Ce via coprecipitation also does not improve the performance of the CuAlFe catalyst because of the formation of a thick CeOx overlayer on the active Cu-FeOx interface, and (iii) impregnation of Ce onto the CuAlFe catalyst exhibits significant improvement in catalytic performance due to the formation of a highly active CeOx-FeOx-Cu interfacial area. In summary, Al does not surface-segregate and serves as a structural promoter, while Ce and Cu surface-segregate and act as functional promoters in Ce/CuAlFe mixed oxide catalysts.