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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 3 M MgBr2 (at 0.6 V) and up to 4–5 times higher adsorption capacity with 3 M MgCl2 (at 1 V). A tradeoff between high CO2 adsorption capacities and lower coulombic efficiencies was observed at voltages above 0.6 V. The energetic and adsorptive performance of the electrodes in the presence of oxygen below 0.5 V was similar to the performance with a CO2/N2 mixture without oxygen at 1 V. 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. [ABSTRACT FROM AUTHOR]

Communication systems are greatly hampered by many disruptive noises in powerline communication systems (PLC), which come with strong interference, resulting in the malfunction of PLC systems. Hence, there is a need to model noise and its effect on communication systems. This paper presents noise modelling and mitigation techniques for indoor broadband powerline communication systems. To model the PLC noise, frequency domain measurements employing the GSP‐930 spectrum analyser were carried out to determine the noise frequency response in the frequency range of 1–30 MHz. The results obtained were plotted. While the analytical model for the noise model is presented, furthermore, noise mitigation techniques for multiple input multiple output PLC (MIMO‐PLC) systems in the form of spatial modulation PLC systems have been proposed. The SM‐PLC system employs the indices of the individual transmit lines to increase the data rate, as opposed to the traditional MIMO‐PLC systems, where the symbol to be transmitted is transmitted by duplicating the symbol across all lines. The proposed system uses the maximum likelihood (ML) detector at the receiver to obtain estimates of the transmitted symbols. The simulation results of the SM‐PLC system are compared with the already existing MIMO‐PLC system and show a significant improvement of ≈6 dB and 5.2 dB in signal‐to‐noise ratio (SNR) at a bit error rate of 10(−5) for spectral efficiencies of 4 bits per channel use (bpcu) and 6 bpcu, respectively. On comparison of the SM‐PLC system having a combination of additive white Gaussian noise and impulse noise at the receiver, the SM‐PLC system outperformed the traditional MIMO‐PLC by 3.5 and 3.8 dB in SNR for 4 and 6 bpcu, respectively. [ABSTRACT FROM AUTHOR]

The development and construction of highway infrastructure are essential in developing countries, whereas its layout and construction sometimes interact with the coastal environment. One problem to attend to is that the outline and geometry designs impact as little as possible on the hydrodynamic circulation of coastal bodies in order to alter the associated ecosystem as little as possible. The study area is located in the north of Colombia, and is made up of a continental coastal zone (Mallorquín Lagoon) and a marine zone (Caribbean Sea), in which a highway is projected that provides communication between two locations. This study presents the application of a numerical model previously developed and modified by the Berkhoff equation, which is developed in a finite difference scheme and has been validated and applied in different works in coastal and fluvial shallow water areas. The application of the model was carried out in a hydrodynamic circulation research project for a one-way highway through a coastal lagoon, where the knowledge of the magnitude of the incident wave height in the structure of the road body is necessary for the design, protection elements, and road geometry. Two numerical simulation scenarios were carried out, specifying normal conditions and extraordinary wave conditions in the month of November with a simulation time of 15 days, obtaining the velocity field associated with coastal currents, waves, and wave modification phenomena, such as refraction, diffraction, and reflection, which provide the height of the incident wave on the highway and the recirculation patterns in the coastal lagoon to identify alterations in the ecosystem. The results of the wave height in each scenario and the velocity field provide values to be used in the design, type of armor, and dimensions of the protection works required for the proper functioning of the road structure. [ABSTRACT FROM AUTHOR]

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 Na2WO4/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 Na2WO4 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 C2Hx and over‐oxidizing CHy to CO and (ii) molten Na2WO4 phase is mainly responsible for over‐oxidation of CH4 to CO2 and also assists in oxidative dehydrogenation of C2H6 to C2H4. These new insights reveal the nature of catalytic active sites and resolve the OCM reaction mechanism over supported Na2WO4/SiO2 catalysts. [ABSTRACT FROM AUTHOR]

Temperature programmed surface reaction spectroscopy (TPSR) is a powerful technique to determine the surface chemistry of bulk metal, supported metal, bulk metal oxide, supported metal oxide, zeolite, and molecular sieve catalysts. It can provide both qualitative and quantitative analysis of the surface active sites present on the catalyst surface, the reaction mechanisms, and kinetics occurring on the catalyst surface by using chemical probe molecules such as alcohols, carboxylates, and specific acidic‐basic reacting gases. In this tutorial review, the highly informative CH3OH chemical probe molecule was used to highlight the information that can be obtained from CH3OH‐TPSR experiments. The CH3OH molecule readily interacts with the catalyst surface to form surface CH3O· and HCOO· intermediates that react to produce HCHO/HCOOCH3/(CH3O)2CH2, CH3OCH3, and CO/CO2 products related to the surface redox, acid and basic nature, respectively. Integration of the CH3OH‐TPSR spectra peaks provide the number of surface active sites. The surface kinetic information provided by CH3OH‐TPSR allows to discriminate between different reaction mechanisms (first‐order, second‐order, Langmuir‐Hinshelwood, and Mars‐van Krevelen). We discuss the uncertainty inherent in CH3OH‐TPSR experiments and address source of errors and detection limits. Web of Science indexed over 800 articles citing TPSR since 1990. A bibliometric analysis identified four clusters of reactions and catalysts: the dominant catalysts for partial oxidation and water gas shift were Ni, Ru, and Pt; CeO2, Co, Cu, Rh, Pd, and perovskites were the main catalysts for combustion and hydrogenation; Ag and zeolites were grouped with reduction; and, Al2O3, ZrO2, SiO2, and V2O5 were applied for dehydrogenation. [ABSTRACT FROM AUTHOR]

In this study, we propose a computational intelligence model for the Internet of Things applications by applying the concept of swarm intelligence (SI) into connected devices. Particularly, decentralized management of smart home energy management system (HEMS) is taken into account in which connected appliances, by sharing information with each other, make the individual decisions for optimizing electricity prices of smart HEMS. Specifically, the study includes two main issues: (a) We propose a framework for decentralized management in smart HEMS; and (b) artificial bee colony (ABC) algorithm, a typical algorithm of SI techniques, has been applied for connected appliances in terms of communication and collaboration with each other to optimize the performance of the energy management system. Moreover, regarding the implementation, we develop and simulate a connected environment of smart home systems to evaluate the proposed approach. The simulation indicates the promising results in terms of optimizing the load balancing problem comparing with the conventional approach of the decentralized management system in smart home applications. [ABSTRACT FROM AUTHOR]

The selective catalytic reduction (SCR) of NOx with NH3 to N2 with supported V2O5(‐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 (V2O5) 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 V2O5/TiO2 catalysts. [ABSTRACT FROM AUTHOR]

The commercial high‐temperature water‐gas shift (HT‐WGS) catalyst consists of CuO‐Cr2O3‐Fe2O3, 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, H2O dissociation, and WGS reaction. These new fundamental insights can potentially guide the rational design of improved iron‐based HT‐WGS catalysts. [ABSTRACT FROM AUTHOR]

Biomass pyrolysis by solid acid catalysts is one of many promising technologies for sustainable production of hydrocarbon liquid fuels and value‐added chemicals, but these complex chemical transformations are still poorly understood. A series of well‐defined model SiO2‐supported alumina catalysts were synthesized and molecularly characterized, under dehydrated conditions and during biomass pyrolysis, with the aim of establishing fundamental catalyst structure–activity/selectivity relationships. The nature and corresponding acidity of the supported AlOx nanostructures on SiO2 were determined with 27Al/1H NMR and IR spectroscopy of chemisorbed CO, and DFT calculations. Operando time‐resolved IR–Raman–MS spectroscopy studies revealed the molecular transformations taking place during biomass pyrolysis. The molecular transformations during biomass pyrolysis depended on both the domain size of the AlOx cluster and molecular nature of the biomass feedstock. These new insights allowed the establishment of fundamental structure–activity/selectivity relationships during biomass pyrolysis. Defining the relationship: A series of well‐defined model SiO2‐supported alumina catalysts were synthesized and molecularly characterized with the aim of establishing fundamental catalyst structure–activity/selectivity relationships. The nature and acidity of the supported AlOx nanostructures on SiO2 were determined with 27Al/1H NMR and IR spectroscopy of chemisorbed CO, and DFT calculations. [ABSTRACT FROM AUTHOR]

Supported isolated vanadium oxide (VO4) species on silica have recently been shown to photocatalytically oxidize methanol selectively to formaldehyde. Insights into support effects and the reactivity of the different supported vanadium oxide species in photocatalytic methanol oxidation are obtained in the present study by varying the support, surface vanadium oxide loading, and synthesis procedure. Isolated and oligomeric surface vanadium oxide species supported on alumina can also photocatalytically oxidize methanol to formaldehyde. Crystalline V2O5 nanoparticles are inactive for photocatalytic conversion of methanol irrespective of the support, but they further convert the formaldehyde produced by the surface vanadium oxide species to surface formate species. The formation of surface formate species is also observed on the bare alumina support. Thermal catalyzed reactions take place at elevated temperatures, leading to product degradation, when attempting to desorb and quantify the photocatalysis products adsorbed on the alumina‐supported samples. This study is a step forward in the directed development of active and selective sites for photocatalysis, and highlights the importance of limitation by desorption in the kinetics of photoreactions. [ABSTRACT FROM AUTHOR]

In this study, evidence is provided that isolated surface vanadia (VO4) species on SiO2 can similarly act as a thermal heterogeneous catalyst and as a heterogeneous photocatalyst. Structurally identical surface VO4 species catalyze the selective oxidation of methanol both by thermal activation and by UV‐light induction. Selectivity to formaldehyde appears to be unity. For the photocatalytic reaction at room temperature, formaldehyde desorption is rate limiting. With larger agglomerates or V2O5 nanoparticles, on the contrary, only the thermal reaction is feasible. This is tentatively attributed to the different positions of electronic states (HOMO/LUMO, valence/conduction band) on the electrochemical energy scale owing to the quantum size effect. Besides providing new fundamental insight into the mode of action of nanosized photocatalysts, our results demonstrate that tuning the photocatalytic reactivity of supported transition‐metal oxides by adjusting the degree of agglomeration is feasible. [ABSTRACT FROM AUTHOR]

The separation, capture, and storage of CO2, the major greenhouse gas, from industrial gas streams has received considerable attention in recent years because of concerns about environmental effects of increasing CO2 concentration in the atmosphere. An emerging area of research utilizes reversible CO2 sorbents to increase conversion and rate of forward reactions for equilibrium-controlled reactions (sorption-enhanced reactions). Little fundamental information, however, is known about the nature of the sorbent surface sites, sorbent surface-CO2 complexes, and the CO2 adsorption/desorption mechanisms. The present study directly spectroscopically monitors Na2O/Al2O3 sorbent-CO2 surface complexes during adsorption/desorption with simultaneous analysis of desorbed CO2 gas, allowing establishment of molecular level structure-sorption relationships between individual surface carbonate complexes and the CO2 working capacity of sorbents at different temperatures. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]

Background Asthma is a common chronic respiratory disease in children and adults. An important genetic component to asthma susceptibility has long been recognized, most recently through the identification of several genes (e.g., ORMDL3, PDE4D, HLA- DQ, and TLE4) via genome-wide association studies. Objective To identify genetic variants associated with asthma affection status using genome-wide association data. Methods We describe results from a genome-wide association study on asthma performed in 3855 subjects using a panel of 455 089 single nucleotide polymorphisms ( SNPs). Result The genome-wide association study resulted in the prioritization of 33 variants for immediate follow-up in a multi-staged replication effort. Of these, a common polymorphism (rs9272346) localizing to within 1 Kb of HLA- DQA1 (chromosome 6p21.3) was associated with asthma in adults ( P-value = 2.2E-08) with consistent evidence in the more heterogeneous group of adults and children ( P-value = 1.0E-04). Moreover, some genes identified in prior asthma GWAS were nominally associated with asthma in our populations. Conclusion Overall, our findings further replicate the HLA- DQ region in the pathogenesis of asthma. HLA- DQA1 is the fourth member of the HLA family found to be associated with asthma, in addition to the previously identified HLA- DRA, HLA- DQB1 and HLA- DQA2. [ABSTRACT FROM AUTHOR]

Summary Background The extrafine-particle formulation of hydrofluoroalkane-beclometasone (EF HFA-BDP; Qvar®) demonstrates improved total and small airway deposition compared with large-particle chlorofluorocarbon (CFC)-BDP. In some short-term studies, EF HFA-BDP provides greater effects on lung function than CFC-BDP, and hence is recommended to be prescribed at a lower dose, but whether there are differences in asthma outcomes during long-term treatment is unknown. Objective To compare the effectiveness of EF HFA-BDP vs. CFC-BDP over 1 year. Methods This retrospective matched cohort study examined outcomes in a large primary care database for patients aged 5-60 years with asthma receiving their first inhaled corticosteroid (ICS) prescription (initiation population) or first ICS dose increase (step-up population) by a pressurized metered-dose inhaler (pMDI) as EF HFA-BDP or CFC-BDP. Patients were matched on baseline demographic and asthma severity measures in EF HFA-BDP:CFC-BDP ratios of 1 : 3 and 1 : 2 for initiation and step-up populations, respectively. Step-up patients were matched also on ICS dose during a baseline year. Co-primary endpoints were asthma control (composite measure comprising no recorded hospital attendance for asthma, oral corticosteroids, or antibiotics for lower respiratory infection) and exacerbation rate during the outcome year. Results For the initiation population (EF HFA-BDP n=2882; CFC-BDP n=8646), adjusted odds of achieving asthma control with EF HFA-BDP vs. CFC-BDP was 1.15 (95% CI 1.02-1.28). For the step-up population ( n=258 and 516), adjusted odds of asthma control with EF HFA-BDP was 1.72 (95% CI 1.14-2.56). EF HFA-BDP was prescribed at a median dose half that of CFC-BDP. Conclusion and Clinical Relevance During 1 year after initiating or stepping up ICS therapy by pMDI, patients who received EF HFA-BDP were more likely to achieve asthma control than those receiving CFC-BDP. These findings suggest that ICS formulation, particle size, and deposition characteristics play important roles in real-life effectiveness of asthma therapy. This study shows that an EF-particle formulation of beclometasone can be used at half the dose of the large-particle formulation with at least as good clinical outcomes. Cite this as: N. Barnes, D. Price, G. Colice, A. Chisholm, P. Dorinsky, E. V. Hillyer, A. Burden, A. J. Lee, R. J. Martin, N. Roche, J. von Ziegenweidt and E. Israel, Clinical & Experimental Allergy, 2011 (41) 1521-1532. [ABSTRACT FROM AUTHOR]

Double-supported metal oxide catalysts, in which an oxide support material with a high surface area is modified by the presence of a second metal oxide surface species added to control the distribution and activity of a third active oxide component, represent a significant challenge in terms of structural characterization. In this study the various components in a double-supported WO/TiO/SiO catalyst system are effectively visualized by using complementary high-angle annular dark field (HAADF) and bright field (BF) imaging within an aberration-corrected scanning transmission electron microscope (STEM). Furthermore, if combined with chemical analysis by electron energy-loss spectroscopy (EELS) and X-ray energy-dispersive spectroscopy (XEDS) within the same STEM instrument, it is possible to map out the relative spatial distribution of all the metal oxide components within the WO/TiO/SiO catalysts. By comparing the structures of a systematic set of WO/TiO/SiO samples that display high, intermediate and low activity for the methanol dehydration reaction, new insight is provided into the structure-performance relationships that exist in this double supported catalyst system. In combining aberration-corrected scanning transmission electron microscope (STEM) imaging and electron energy-loss spectroscopy (EELS) analysis, it is possible to map out the atomic structure and relative distribution of various metal oxide components in complex double-supported metal oxide catalysts (see figure). [ABSTRACT FROM AUTHOR]

Exercise-induced (EI) hypersensitivity disorders are significant problems for both recreational and competitive athletes. These include EI-asthma, EI-bronchoconstriction, EI-rhinitis, EI-anaphylaxis and EI–urticaria. A group of experts from the European Academy of Allergology and Clinical Immunology and the American Academy of Allergy Asthma and Immunology met to discuss the pathogenesis of these disorders and how to diagnose and treat them, and then to develop a consensus report. Key words (exercise with asthma, bronchoconstriction, rhinitis, urticaria or anaphylaxis) were used to search Medline, the Cochrane database and related websites through February 2008 to obtain pertinent information which, along with personal reference databases and institutional experience with these disorders, were used to develop this report. The goal is to provide physicians with guidance in the diagnosis, understanding and management of EI-hypersensitivity disorders to enable their patients to safely return to exercise-related activities. [ABSTRACT FROM AUTHOR]

Background: The number of Sp1–Egr1 binding tandem repeats at the ALOX5 promoter influences gene transcription and may modify the response to anti-leukotriene treatment. The relationship of ALOX5 variants to asthma severity and leukotriene production by eosinophils is unknown. Objective: To characterize ALOX5 mRNA expression and cysteinyl-leukotriene production by eosinophils from individuals bearing ALOX5 promoter deletional variants and their association with the severity of childhood asthma. Methods: Eosinophils from adult asthmatics bearing only variant alleles (with other than five tandem repeats on both chromosomes, non5/non5) or no variant alleles (5/5) were cultured in vitro and ALOX5 expression and leukotriene secretion were measured. A total of 621 children with mild or moderate-severe asthma were genotyped at the ALOX5 core promoter. Results: Asthmatics with non5/non5 genotype expressed less ALOX5 mRNA and produced less LTC4 into culture supernatants than 5/5 individuals (6.4 ± 2.0 and 20.0 ± 5.0 pg/ml, n = 5; P < 0.05). More asthmatic children bearing non5/non5 genotype had moderate-severe asthma than children with the 5/5 genotype (5.3% vs. 1.4%, P = 0.008). Multivariate logistic regression identified ALOX5 promoter genotype as a significant predictor of disease severity (OR = 3.647, 95% CI: 1.146–11.608, P = 0.03). Consistent with these findings, children bearing the non5/non5 genotype had greater bronchomotor response to exercise as measured by the maximum fall after exercise and the area under the exercise curve ( P < 0.05 for both). Conclusion: Our results suggest that children who express the asthma phenotype despite having a genetic variant that impairs their ability to express ALOX5 have more severe disease and thus are more likely to have asthma symptoms. [ABSTRACT FROM AUTHOR]

BackgroundT cells have been implicated in the pathogenesis of atopic asthma. We have previously shown that memory T helper cells (CD4+CD45RO+) are preferentially activated relative to naïve T helper cells (CD4+CD45RA+) after bronchial allergen challenge. However, specific T helper subpopulations that are activated in atopy and/or asthma remain undefined. ObjectiveTo determine the T helper subpopulations and activation phenotypes relevant to acute and stable asthma that may be common with or distinct from atopy. MethodsTwo groups of atopic asthmatics (ten acute and nine stable asthmatics) and two non-asthmatic groups (14 non-asthmatic atopics and eight normal non-atopic controls) were analysed. Ten acute asthmatics were assessed in the emergency room during an acute episode (FEV1 43.6% ± 18.4). Nine stable asthmatics were assessed during a symptom-free period (FEV1 85% ± 6). Using multiple colour flow cytometry we analysed T cell subpopulations and the expression of IL-2-receptor (IL-2R) and MHC-class II antigens (MHC II) on naïve and memory T helper cells in the peripheral blood of asthmatic and non-asthmatic groups. ResultsAtopic asthmatics (acute and stable) had an increased percentage of memory T helper cells expressing IL-2R compared with normal non-atopics (mean SD 16.1 ± 6%, 12.4 ± 2% and 7.7 ± 1.8%, P < 0.05) but not compared with non-asthmatic atopics (10 ± 3.5%). Naïve T helper cells had low expression of IL-2R and MHC II in all four groups. MHC II antigen expression was increased in memory T helper cells of asthmatics (acute and stable) compared with normal non-atopics (13.9 ± 7.5, 10.6 ± 5 and 4.9 ± 2.5, P < 0.05) but not compared with non-asthmatic atopics (7.92 4). A novel finding was that IL-2R and the MHC II molecules were mainly expressed in non-overlapping populations and coexpression was found predominantly on memory T... [ABSTRACT FROM AUTHOR]

Maternal IgG is transferred to the suckling mouse and rat through a major histocompatibility complex (MHC) class I-related Fc receptor (FcRn) on the brush border of the proximal small intestine. We have previously described a site on the epithelial surface of the human fetal intestine with IgG binding characteristics similar to FcRn. We report here the identification by reverse transcriptase polymerase chain reaction amplification and sequencing of the human orthologue of rat and mouse FcRn in tissue obtained from human fetal and adult intestine. FcRn protein was detected in adult human intestine by western blot. Immunohistochemical studies of sections of human intestine show that the FcRn is localized mostly to the epithelial cells, where it is in the apical region. These data suggest that the binding of IgG previously seen in the fetal intestine is due to the presence of FcRn. Potential roles for this MHC class I-like Fc receptor in the human intestine include the transfer of passive immunity, induction of oral tolerance, and immunosurveillance. [ABSTRACT FROM AUTHOR]

The mechanisms that regulate immunoglobulin G (IgG) catabolism are little understood. We have previously found unusually low IgG concentrations in sera of mice homozygous for a targeted disruption of the β2-microglobulin gene. We therefore investigated whether this might result, at least in part, from increased clearance of IgG from the systemic circulation in mice lacking β2-microglobulin. We compared the half-lives of radiolabelled mouse IgGl injected intravenously into β2-microglobulin-/- mice and wild-type or heterozygous siblings. The clearance of 125I-labelled IgG1 was strikingly more rapid in the mice lacking β2-microglobulin. β2-microglobulin-/- mice lack functional molecules of the MHC class I-related Fc receptor, FcRn. Some mutations in mouse IgG1 that increase its clearance have recently been shown to prevent binding to FcRn in the gut. To determine whether the slower degradation of immunoglobulin in mice with β2-microglobulin correlated with the ability of the antibody to bind FcRn, we measured the clearance of chicken IgY, which does not bind this receptor. The 125I-labeiled IgY was catabolized equally rapidly in β2-microglobulin-deficient and wild-type mice. We compared the half-lives of the four subclasses of mouse IgG in β2-microglobulin-/-, +/-, and +/+ mice to determine whether the difference we had noted for IgG1 was peculiar to this subclass. The 125I-labelled IgG of all subclasses, with the possible exception of IgG2b, was degraded more rapidly in the β2-microglobulin-deficient mice than in heterozygous or wild-type siblings. These data suggest that FeRn can protect IgG from degradation, and is therefore important in maintaining IgG levels in the circulation. [ABSTRACT FROM AUTHOR]

This work elucidates the structural evolution of a commercial‐type iron oxide‐based high temperature water–gas shift (HT‐WGS) catalyst during activation and deactivation stages. The findings highlight the importance of Cu–FeOx interfaces. Based on the new insights, future improvement of commercial iron‐based catalysts should focus on stabilization of the active Cu–FeOx interface. Much effort has been devoted to understanding the structure, mechanism, and promotion of the commercial‐type CuO–Cr2O3–Fe2O3 catalyst for the high temperature water–gas shift (HT‐WGS) reaction. However, structural evolution of the catalyst during the activation and deactivation stages was rarely reported. Herein, catalyst characterization, temperature‐programmed studies, and kinetic analysis were conducted on iron oxide‐based HT‐WGS catalysts. Addition of Cu was found to accelerate both the bulk (Fe2O3 → Fe3O4) and surface (active FeOx–Cu interface) transformations during the catalyst activation stage. During catalyst deactivation, Cu accelerated both sintering of the Fe3O4 bulk phase and unfavorable encapsulation of the metallic Cu particles with a substantial FeOx overlayer. The loss of the initial active Cu–FeOx interfacial sites reversed the promotional effect of Cu. [ABSTRACT FROM AUTHOR]

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