High Initial Activity Research Articles

Greener Selective Cycloalkane Oxidations with Hydrogen Peroxide Catalyzed by Copper-5-(4-pyridyl)tetrazolate Metal-Organic Frameworks.

Microwave assisted synthesis of the Cu(I) compound [Cu(µ4-4-ptz)]n [1, 4-ptz = 5-(4-pyridyl)tetrazolate] has been performed by employing a relatively easy method and within a shorter period of time compared to its sister compounds. The syntheses of the Cu(II) compounds [Cu3(µ3-4-ptz)4(µ2-N3)2(DMF)2]n∙(DMF)2n (2) and [Cu(µ2-4-ptz)2(H2O)2]n (3) using a similar method were reported previously by us. MOFs 1-3 revealed high catalytic activity toward oxidation of cyclic alkanes (cyclopentane, -hexane and -octane) with aqueous hydrogen peroxide, under very mild conditions (at room temperature), without any added solvent or additive. The most efficient system (2/H2O2) showed, for the oxidation of cyclohexane, a turnover number (TON) of 396 (TOF of 40 h−1), with an overall product yield (cyclohexanol and cyclohexanone) of 40% relative to the substrate. Moreover, the heterogeneous catalytic systems 1–3 allowed an easy catalyst recovery and reuse, at least for four consecutive cycles, maintaining ca. 90% of the initial high activity and concomitant high selectivity.

Efficient hydrogen production from glycerol by steam reforming with carbon supported ruthenium catalysts

Various carbon materials differing in surface area, nanostructure and grade of graphitization were used to support ruthenium catalysts for the steam reforming of glycerol. Activity measurements performed in a traditional reactor indicated that the reaction is structure sensitive and the initial activity for hydrogen production of the catalysts decreases with decreasing Ru particle size. Among the most active catalysts, stability in reaction was first related with the graphitization degree of the support. Ru-nanotubes was the most stable with the time on stream, whereas Ru-activated carbon underwent an abrupt deactivation due to carbon gasification. Ru-graphite, the other catalyst with highest initial activity, suffered from a slow deactivation, most likely due to coke formation derived from the olefins produced during reaction. The use of a membrane reactor prevents the formation of these undesired compounds, enhancing the hydrogen yield and rendering a very stable catalyst.

7-6-7 Ring-based transition-metal catalysts for the transfer dehydrogenation of isopropanol

A family of 7-6-7 ring-based PCP pincer iridium/rhodium complexes has been applied to the transfer dehydrogenation of isopropanol to give acetone using tert-butylethylene (TBE) as the hydrogen acceptor. For the iridium complexes, high initial activity was achieved with the turnover number (TON) being as high as 6000 after 2 h at 200 °C, even when TBE was present in high concentration (6000 equivalents). The inhibition effect of TBE was found to be somewhat weaker than in the case of alkane dehydrogenation using the same catalysts. Whereas the corresponding rhodium complex was inactive in alkane dehydrogenation, it was unexpectedly found to have a catalytic activity of 2000 TONs (3000/1 TBE/catalyst ratio) after 2 h at 200 °C in the same transfer dehydrogenation. The bonding properties of the reactive complexes were investigated through natural bond orbital (NBO) analysis and compared.

Mechanistic studies of aldol condensations in UiO-66 and UiO-66-NH2 metal organic frameworks

A full mechanistic investigation is proposed for the industrially important cross-aldol condensation reaction of heptanal with benzaldehyde on the UiO-66 and the amino-functionalized UiO-66-NH2 metal–organic frameworks to form jasminaldehyde. Several experimental studies indicate that the activity for the aldol condensation reaction can be increased by proper functionalization of the material, e.g. by introducing an additional basic amino site and thus creating a bifunctional acid–base catalyst for the aldol condensation. The precise molecular level origin for this behavior is to date unclear. Herein state-of-the-art Density-Functional Theory (DFT) calculations have been performed to unravel the mechanism of the cross- and self-aldol condensations of benzaldehyde and propanal. To this end free energy calculations have been performed on both extended cluster and periodic models. It is found that the mechanism on both catalysts is essentially the same, although a slightly stronger adsorption of the reactants and slightly lower barriers were found on the amino functionalized material, pointing toward higher initial activities. New experiments were performed to confirm these observations. It is indeed found that the initial activity toward cross-aldol condensation on the amino functionalized material is higher, although after about 40min of reaction both materials become equally active. Our results furthermore point out that the basic amino groups may promote side reactions such as imine formation, which is induced by water. The study as presented can assist to engineer materials at the molecular level toward the desired products.

Efficient hydrogen production from ethanol steam reforming over La-modified ordered mesoporous Ni-based catalysts

This paper describes the synthesis of a group of meso-xLaNiAl catalysts with ordered mesostructure and La promoters, and their catalytic performance for hydrogen production from ethanol steam reforming. For comparison, the conventional 0LaNiAl catalyst was prepared by impregnation with γ-Al2O3. The characterization results exhibited that meso-xLaNiAl materials possessed excellent textural properties, such as high specific surface areas, large pore volumes and uniform pore sizes. The ordered mesostructure was beneficial to obtain and maintain the 4–6nm Ni nanoparticles, which were smaller than that of the conventional 0LaNiAl catalyst (∼10nm). Consequently, meso-xLaNiAl catalysts exhibited superior initial activity with respect to the reference 0LaNiAl catalyst, especially at higher temperatures (873 and 973K). Particularly, the meso-3LaNiAl catalyst gained the highest amount of easily reduced Ni species and then the highest active surface areas. In addition, the highest initial activity at 873K is exhibited over meso-3LaNiAl catalyst, which is mainly attributed to the highly dispersed nickel nanoparticles and abundant active surface areas. The meso-3LaNiAl catalyst also exhibited excellent long-term stability. Besides the excellent textural properties, the presence of La-modifiers enhanced the basicity of the catalyst, strengthened the metal-support interaction and cleaned the deposited carbon, resulting in the suppression of carbon deposition and the improvement of stability.

SrCo(0.9)Ti(0.1)O(3-δ) As a New Electrocatalyst for the Oxygen Evolution Reaction in Alkaline Electrolyte with Stable Performance.

The development of efficient, inexpensive, and stable electrocatalysts for the oxygen evolution reaction (OER) is critical for many electrochemical energy conversion technologies. The prohibitive price and insufficient stability of the state-of-the-art IrO2 electrocatalyst for the OER inhibits its use in practical devices. Here, SrM0.9Ti0.1O3-δ (M = Co, Fe) perovskites with different B-site transition metal elements were investigated as potentially cheaper OER electrocatalysts. They were prepared through a typical sol-gel route, and their catalytic activities for the OER in alkaline medium were comparatively studied using rotating disk electrodes. Both materials show high initial intrinsic activities in alkaline electrolyte for the OER, comparable to the benchmark perovskite-type electrocatalyst Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), but SrCo0.9Ti0.1O3-δ (SCT) possessed more operational stability than SrFe0.9Ti0.1O3-δ (SFT), even better than BSCF and IrO2 catalysts. Based on the X-ray photoelectron spectra analysis of the oxidation states of the surface Co/Fe in both SFT and SCT before and after the OER tests, an explanation for their different operational stabilities was proposed by adopting a reported activity descriptor correlated to the eg occupancy of the 3d electron of the surface transition metal cations in the perovskite oxides. The above results indicate that SCT is a promising alternative electrocatalyst for the OER and can be used in electrochemical devices for water oxidation.

Ag-based semiconductor photocatalysts in environmental purification

Over the past decades, with the fast development of global industrial development, various organic pollutants discharged in water have become a major source of environmental pollution in waste fields. Photocatalysis, as green and environmentally friendly technology, has attracted much attention in pollutants degradation due to its efficient degradation rate. However, the practical application of traditional semiconductor photocatalysts, e.g. TiO2, ZnO, is limited by their weak visible light adsorption due to their wide band gaps. Nowadays, the study in photocatalysts focuses on new and narrow band gap semiconductors. Among them, Ag-based semiconductors as promising visible light-driven photocatalysts have aroused much interesting due to their strong visible light responsibility. Most of Ag-based semiconductors could exhibit high initial photocatalytic activity. But they easy suffer from poor stability because of photochemical corrosion. Design heterojunction, increasing specific surface area, enriching pore structure, regulating morphology, controlling crystal facets, and producing plasmonic effects were considered as the effective strategies to improve the photocatalytic performance of Ag-based photocatalyts. Moreover, combining the superior properties of carbon materials (e.g. carbon quantum dots, carbon nano-tube, carbon nanofibers, graphene) with Ag-based semiconductor could produce high efficient composite photocatalyts.

Zr-doped CeO2 nanorods as versatile catalyst in the epoxidation of styrene with tert-butyl hydroperoxide as the oxidant

The CeO2 nanorods with various Zr dopant concentrations were studied in terms of their activity in the selective oxidation of styrene to styrene oxide using tert–butyl hydroperoxide as the oxidant. Several techniques were used to characterize the synthesized Zr-doped CeO2 nanorods. The results indicated that Zr ions were doped into the ceria lattice and formed fluorite-like solid solutions, resulting in an increase in oxygen vacancy concentration. It was also found that Zr content has a significant impact on intrinsic natures of the catalyst, namely, the specific surface area, oxygen vacancy concentration and the content of Ce3+ ions, which were found to determine the catalytic efficiency of the catalyst in the epoxidation of styrene. It is interesting that the remarkably increased catalytic performance of the ceria nanorods with 10mol% zirconium is mainly attributed to the more oxygen vacancy and the higher percentage of Ce3+. Furthermore, recycling studies proved the heterogeneous zirconium-doped ceria nanorods did not lose the initial high catalytic activity after five successive recycles.

On the Origin of Enhanced ORR Activity of RuO2 Nanosheet Modified Pt Catalysts: An Impedance Spectroscopy Approach

Numerous approaches have been proposed to increase the ORR activity of Pt, including the use of alloys or core-shell structures, oxide additives, graphitized carbon, and others. Although these catalysts have improved activity and/or durability, the preparation scheme for such state-of-the-art catalysts is often multi-process and difficult to produce in large scale. In terms of simplicity of synthesis, the ideal method may be to have a catalyst with high initial activity and durability by making a composite with a commercial Pt/C by a simple one-step process. We have recently reported such a catalyst by mixing ruthenium oxide nanosheets with practical Pt/C [1-7]. Catalysts composed of RuO2 nanosheet and Pt/C (RuO2ns-Pt/C) can be prepared by simply mixing and drying of the two colloids and exhibits higher initial ORR activity and at the same time shows improved performance after accelerated durability cycling tests. However, the reason(s) for the initial activity improvement is poorly understood. For example, the increase (30%) in electrochemically active surface area can only partially explain the initial activity increase. In this study, we focus on the clarifications of the increase in the initial activity of the RuO2ns-Pt/C catalysts with composites prepared with nanosheets having different lateral size by electrochemical impedance spectroscopy and transmission line model simulations. Nanosheets with smaller size resulted in higher activity, which was correlated to a decrease in pore resistance. The initial mass activity of Pt/C is j k=285 A (g-Pt)-1 at 0.85 V vs RHE in 0.5M H2SO4 at 60°C. Addition of 100 nm RuO2 nanosheet improved the initial mass activity to j k=412 A (g-Pt)-1. The impedance spectra were conducted at open charge potential in N2 saturated 0.5M H2SO4 electrolyte at 60°C and simulated with the transmission line model. From the simulation, resistivity in the porous Pt/C was 625 Ω cm-1 whereas with the addition of 100 nm RuO2 nanosheet, resistivity was only 125 Ω cm-1. Addition of nanosheet improved the conductivity in the catalyst layer. The impedance spectra conducted at 0.85V vs RHE in O2 saturated 0.5M H2SO4 electrolyte at 60°C showed that addition of smaller size nanosheet improved the charge transfer reaction of the ORR. This work was supported in part by the “Polymer Electrolyte Fuel Cell Program” from the New Energy and Industrial Technology Development Organization (NEDO), Japan. [1] W. Sugimoto, T. Saida, Y. Takasu, Electrochem. Commun., 8, 411 (2006). [2] T. Saida, W. Sugimoto, Electrochim. Acta, 55, 857 (2010). [3] T. Saida, N. Ogiwara, Y. Takasu, W. Sugimoto, J. Phys. Chem. C, 114, 13390 (2010). [4] D. Takimoto, C. Chauvin, W. Sugimoto, Electrochem. Commun, 33, 123 (2013). [5] Q. Liu, K. S. Lokesh, C. Chauvin, W. Sugimoto, J. Electrochem. Soc., 161(3), F259 (2014). [6] C. Chauvin, T. Saida W. Sugimoto, J. Electrochem. Soc., 161, F318 (2014). [7] Q. Liu, C. Chauvin, W. Sugimoto, J. Electrochem. Soc., 161(3), F360 (2014).

Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections.

Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25–0.75, and 2.5–7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40–50 nm and width 5–6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug resistant infection.

Au/TS-1 catalyst prepared by deposition–precipitation method for propene epoxidation with H2/O2: Insights into the effects of slurry aging time and Si/Ti molar ratio

Au/TS-1 catalyst prepared by deposition–precipitation method is efficient for propene epoxidation with H2/O2, and its performance is significantly affected by the preparation parameters and the properties of support. In this work, effects of the slurry aging time and Si/Ti ratio of support on the location of Au nanoparticles inside or outside the micropores of TS-1 supports are examined by multi-techniques such as in situ characterization and molecular dynamics simulation, and the as-obtained catalysts are tested for propene epoxidation. It is found that longer slurry aging time facilitates the evolution of Au complex into smaller sized species which is easier to locate inside the micropores. Accordingly, the as-reduced catalyst has more tiny Au nanoparticles that are extremely active inside micropores and shows higher initial PO formation rate (gPOh−1gAu−1). In addition, high Si/Ti ratio of TS-1 also favors the deposition of Au nanoparticles inside micropores, resulting in higher initial activity but lower stable activity.

Phosphomonoesterase Activities, Kinetics and Thermodynamics in a Paddy Soil After Receiving Swine Manure for Six Years

Soil phosphomonoesterase plays a critical role in controlling phosphorus (P) cycling for crop nutrition, especially in P-deficient soils. A 6-year field experiment was conducted to evaluate soil phosphomonoesterase activities, kinetics and thermodynamics during rice growth stages after consistent swine manure application, to understand the impacts of swine manure amendment rates on soil chemical and enzymatic properties, and to investigate the correlations between soil enzymatic and chemical variables. The experiment was set out in a randomized complete block design with three replicates and five treatments including three swine manure rates (26, 39, and 52 kg P ha−1, representing low, middle, and high application rates, respectively) and two controls (no-fertilizer and superphosphate at 26 kg P ha−1). The results indicated that the grain yield and soil chemical properties were significantly improved with the application of P-based swine manure from 0 to 39 kg P ha−1; however, the differences between the 39 (M39) and 52 kg P ha−1 treatments (M52) were not significant. The enzymatic property analysis indicated that acid phosphomonoesterase was the predominant phosphomonoesterase in the tested soil. The M39 and M52 treatments had relatively high initial velocity (V0), maximal velocity (Vmax), and activation grade (lgNa) but low Michaelis constant (Km), temperature coefficient (Q10), activation energy (Ea), and activation enthalpy (ΔH), implying that the M39 and M52 treatments could stimulate the enzyme-catalyzed reactions more easily than all other treatments. The correlation analysis showed that the distribution of soil phosphomonoesterase activities mainly followed the distributions of total C and total N. Based on these results, 39 kg P ha−1 could be recommended as the most appropriate rate of swine manure amendment.

Precious metal-promoted Ni–Mg–Al–Fe–O catalyst for hydrogen production with fast startup via catalytic partial oxidation of butanol

The layered double hydroxides (LDH)-derived Ni–Mg–Al–Fe–O catalyst with/without precious metals of Rh, Ir, Ru and Pt was prepared by co-precipitation and impregnation, and tested in catalytic partial oxidation (CPOX) of butanol for fast and variable hydrogen production. The results of X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR) indicate that the Ni–Mg–Al–Fe–O catalyst without reduction has an induction period up to 8 h at 700 °C in the CPOX process because of the slow reduction of Ni species in solid solution of Mg(Ni)O during the CPOX process. With promotion of Rh in Ni–Mg–Al–Fe–O, there was high initial activity near 4.1 mol-H2/mol-butanol because the reducibility was improved and the Ni0 species emerged in the beginning and remained stable, suggesting that the Rh-NMAF catalysts can be a promising candidate with high initial activity and stability in CPOX of butanol for hydrogen production, especially for variable hydrogen supply for on-board applications. The Ni–Mg–Al–Fe–O catalyst promoted by Ir, Ru and Pt also showed potential in CPOX of butanol for hydrogen production.

A Polarity Switching Technique for the Efficient Production of Sodium Hypochlorite from Aqueous Sodium Chloride Using Platinum Electrodes

A novel, periodic polarity-switching technique is developed for the electrolytic production of sodium hypochlorite from aqueous sodium chloride. The technique employs a flow-through cell having two identical platinum electrodes. Polarities of these electrodes are periodically swapped. The main purpose of this step is to prevent the growth of platinum oxide film and thereby retain high initial activity of the electrodes throughout the operation. The performance of this mode of operation is evaluated using the cumulative productivity and current efficiency of the cell as indicators. Typical ranges of parameters used are as follows: concentration of Cl– ions, 0.1–0.5 M; switching frequency, 0.01–1 Hz; and current density, 100–700 A m–2. The productivity of the switching mode is 5–6 times higher and its current efficiency is 15%–20% higher than that of the DC mode. The switching frequency has a strong influence on both the cumulative production rate and the average current efficiency and an optimal switching ...

Nickel‐Supported on La2Sn2O7 and La2Zr2O7 Pyrochlores for Methane Steam Reforming: Insight into the Difference between Tin and Zirconium in the B Site of the Compound

AbstractLa2Sn2O7 and La2Zr2O7, two pyrochlore compounds with different B‐site cations, were prepared and used as supports for Ni in methane steam reforming. Compared with Ni/γ‐Al2O3, both Ni/La2Zr2O7 and Ni/La2Sn2O7 show very stable reaction performance. Whereas Ni/La2Zr2O7 also displays reasonably high activity for the reaction, the activity of Ni/La2Sn2O7 is extremely low. It was found that severe coking occurred with Ni/γ‐Al2O3, but no coke formation was observed on the two pyrochlore catalysts. On the reduced and spent Ni/La2Sn2O7 catalyst, the Ni3Sn2 and Ni3Sn alloys were detected; these alloys suppressed coke formation but also decreased the activity of the catalyst. In comparison, a large amount of La2O2CO3 was formed on the used Ni/La2Zr2O7 catalyst; these species reacted with the carbon deposits formed on the Ni particles and continuously restored the Ni sites. Thus, coking was effectively suppressed and the initial high activity of the catalyst was maintained. Thus, Ni/La2Zr2O7 is a superior catalyst having the potential for industrial use.

Hydrothermal treatment on ZSM-5 extrudates catalyst for methanol to propylene reaction: Finely tuning the acidic property

ZSM-5 powder and extrudates are hydrothermally treated by varying temperature and time. Before and after treatment, the materials are characterized and evaluated in the methanol to propylene (MTP) process. The changes in textural properties are compared and particular attention is paid to the nature, number, and ratio of Brønsted (B) and Lewis (L) acid sites. The extrudates catalyst contains substantially a large number of acid sites, especially the L acid sites and hierarchical porous structure due to the addition of the alumina binder. The number of acid sites and the B/L ratio could be finely adjusted by proper hydrothermal treatment. And the hydrothermal treatment parameter on the extrudates plays an important effect on its MTP catalytic performance and product distribution. After steaming at 500°C for 12h, both the zeolite and extrudates catalyst show a high initial activity, achieving ca. 12 percentage point rise in the propylene selectivity during the MTP reaction. However, with time on stream, the treated extrudates perform the steady propylene selectivity (around 43%) and in particular the longest was 89h of catalytic lifetime, compared to the non-treated extrudates (45h) and treated zeolite (57h). The enhanced catalytic performance could be contributed by the appropriate B/L ratio and number of acid sites, in combination with the mesoporous structure, which are crucial for decreasing the hydrogen transfer reaction and inhibiting the coke deposition.

Resveratrol Demonstrates Antimicrobial Effects Against Propionibacterium acnes In Vitro.

IntroductionResveratrol (3,5,4′-trihydroxystilbene) is an antioxidant that has multiple biologic effects including antimicrobial properties. Acne vulgaris is a disease of the pilosebaceous unit, characterized by an inflammatory host immune response to the bacteria Propionibacterium acnes (P. acnes). This study sought to determine whether resveratrol may be a potential treatment for acne vulgaris.MethodsColony-forming unit (CFU) assays together with transmission electron microscopy using P. acnes treated with resveratrol or benzoyl peroxide were used to assess antibacterial effects. Blood was drawn from healthy human volunteers, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays were used to assess cytotoxicity in monocytes and keratinocytes.ResultsResveratrol demonstrated sustained antibacterial activity against P. acnes, whereas benzoyl peroxide, a commonly used antibacterial treatment for acne, demonstrated a short-term bactericidal response. A combination of resveratrol and benzoyl peroxide showed high initial antibacterial activity and sustained bacterial growth inhibition. Electron microscopy of P. acnes treated with resveratrol revealed altered bacterial morphology, with loss of membrane definition and loss of well-defined extracellular fimbrial structures. Resveratrol was less cytotoxic than benzoyl peroxide.ConclusionThe sustained antibacterial activity and reduced cytotoxicity versus benzoyl peroxide demonstrated by resveratrol in this study highlight its potential as a novel therapeutic option or adjuvant therapy in the treatment of acne vulgaris.Electronic supplementary materialThe online version of this article (doi:10.1007/s13555-014-0063-0) contains supplementary material, which is available to authorized users.

Extension study of participants from the trial of early aggressive therapy in juvenile idiopathic arthritis.

To follow children with juvenile idiopathic arthritis (JIA) who had completed at least 6 months of the TRial of Early Aggressive Therapy (TREAT) clinical study for an additional 2 years, describing safety of early aggressive treatment, disease activity, function, and duration of clinical inactive disease (CID) during followup. Children were treated as per provider's discretion. Physician, patient/parent, and laboratory measures of disease status as well as safety information were collected at clinic visits every 3 months for up to 2 years. Forty-eight children were followed for a mean of 28 months (range 12-42) beyond the end of the TREAT study. Half of patients were in CID for > 50% of their followup time. Overall, 88% of patients achieved CID at > 1 study visit and 54% achieved clinical remission while taking medication. Six patients were in CID for the duration of the study, and, of those, 2 achieved a full year of clinical remission while not taking medication. Active disease was mild: mean physician's global assessment 2.4, active joint count 3.5, parent global evaluation 2.4, Childhood Health Assessment Questionnaire 0.32, erythrocyte sedimentation rate 19 mm/h, and morning stiffness 23 min. There were no serious adverse events or adverse events reported at grade 3 or higher of Common Terminology Criteria for Adverse Events. Early aggressive therapy in this cohort of patients with polyarticular JIA who had high initial disease activity was associated with prolonged periods of CID in the majority of patients during followup. Those not in CID had low levels of disease activity.

Comparisons of Barley Malt Amylolytic Enzyme Thermostabilities to Wort Osmolyte Concentrations, Malt Extract, ASBC Measures of Malt Quality, and Initial Enzyme Activities

The hypothesis that wort osmolyte concentration (OC) would correlate much better than malt extract (ME) with barley amylolytic enzyme thermostabilities of malts produced over several days of germination was tested. Seeds of four two-row and four six-row North American barley cultivars were malted in a micromalter and sampled every 24 hr throughout 6 days of germination. α- and β-amylases and limit dextrinase were assayed before and after mashing at 70°C for 30 min to determine thermostabilities. Wort OC, ME, and ASBC measures of malt quality were determined for each day of germination. For all cultivars combined, over all days of germination, wort β-amylase thermostabilities correlated negatively and highly significantly with both wort OC and ME, although more strongly with OC (r = −0.62, P < 0.0001; r = −0.46, P < 0.001, respectively). Correlations of limit dextrinase thermostabilities with wort OC were also much stronger than with ME (r = −0.87, P < 0.0001; r = −0.68, P < 0.0001, respectively). α-Amylase thermostability was either unaffected by or increased after mashing at 70°C. These data suggest that β-amylase and limit dextrinase thermostabilities become more limiting to starch degradation as reflected by OC than as reflected by ME as germination proceeds. β-Amylase intron III allelic variation had no effect on OC or ME in these North American barley cultivars. For all cultivars combined over 6 days of germination, the correlations for β-amylase and limit dextrinase thermostabilities versus the initial activities of α- and β-amylase and limit dextrinase were significant and negative ([β-amylase thermostabilities versus initial activities of α-amylases: r = −0.63, P < 0.0001, β-amylases: r = −0.68, P < 0.0001, and limit dextrinases: r = −0.54, P < 0.0001] and [dextrinase thermostabilities versus initial activities of α-amylase: r = −0.63, P < 0.0001, β-amylase: r = −0.68, P < 0.0001, and limit dextrinase: r = −0.54, P < 0.0001]). These data suggest that selection for high initial activity of any of these amylolytic enzymes would also select for high thermostability of β-amylase and limit dextrinase.

A comparison of N-containing carbon nanostructures (CNx) and N-coordinated iron–carbon catalysts (FeNC) for the oxygen reduction reaction in acidic media

In light of the debate about the role of the transition metal in non-precious metal catalysts (NPMCs), two different NPMCs, CNx and FeNC, were compared for activity toward oxygen reduction in acidic media and characterized using various techniques, including X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES), extended X-ray absorption fine structure (EXAFS), superconducting quantum interference device (SQUID) magnetometry, inductive-couple plasma optical emission spectrometry (ICP-OES), and temperature-programmed oxidation (TPO). The effect of acid-washing as well as long-term exposure to fuel cell and half-cell environment on both catalysts was also studied. Although FeNC exhibited a much higher initial activity than CNx, it was seen to degrade rapidly in both half-cell and fuel cell environments, while CNx retained much of its initial activity. The results discussed are sought to clarify some of the ambiguity in the role of the transition metal in these two catalysts and help establish that they are indeed two different materials with different active sites that catalyze ORR.