Enhanced catalytic performance of MnxOy-Na2WO4/SiO2 for the oxidative coupling of methane using an ordered mesoporous silica support

The oxidative coupling of methane is a highly promising reaction for its direct conversion. Silica supported MnxOy–Na2WO4 is a suitable catalyst for this reaction. In this study, a variety of different SiO2 materials have been tested as supports. Surprisingly, the application of ordered mesoporous silicas, here exemplarily shown for SBA-15 as support materials, greatly enhances the catalytic performance. The CH4 conversion increased two fold and also the C2 selectivity is strongly increased

Oxygen Exchange on Vanadium Pentoxide

The isotopic exchange of 18O2 on polycrystalline V216O5 was studied by Raman spectroscopy at different temperatures between 300 and 580 °C and in the presence of different mixtures of oxygen with ethane, propane, or n-butane in the gas phase. Supported by DFT calculations, a method was developed to determine which of the three differently coordinated oxygen atoms in the crystal structure of V2O5 (vanadyl oxygen O1, 2-fold-coordinated oxygen O2, and three-coordinated oxygen O3) are involved in the exchange with 18O2 from the gas phase. Thus, it was found that the band at 994 cm–1, which is commonly exclusively assigned to a V═16O1 stretching (Ag) vibration, also contains contributions of an 16O1–V–16O2 stretching vibration (B2g). If only the O1 position is exchanged, the B2g component shifts to 964.2 cm–1, while if both O1 and O2 are exchanged, a shift to 953.4 cm–1 is expected. In contrast, the Ag component shifts only to 955 cm–1, regardless of whether only the O1 position or all three oxygen atoms are exchanged. On this basis, it was found that oxygen exchange at 573 °C in absence of an alkane involves O1 and O3 atoms, whereas in the presence of propane all three oxygen atoms are exchanged. In the latter case, the overall exchange rate appears to be limited by bulk diffusion. At typical reaction temperatures for the oxidative dehydrogenation of propane between 320 and 430 °C, no exchange occurs in pure oxygen. In presence of ethane or propane, only O1 is partly exchanged possibly at the surface and/or in a near-surface region. Under the typical reaction conditions of oxidative dehydrogenation of propane at 400 °C, there is hardly any variation in the spectra, and the small changes observed after long times on stream only affect O1, which, considering the sensitivity of the measurement method, leaves open whether the Mars–van Krevelen mechanism is indeed the predominant reaction mechanism under the conditions of oxidative dehydrogenation of alkanes on V2O5

Signal Transmission in the Auditory System

Contains table of contents for Section 3 and reports on four research projects.National Institutes of Health Grant R01 DC00194National Institutes of Health Grant P01 DC00119National Science Foundation Grant IBN 96-04642W.M. Keck Foundation Career Development ProfessorshipNational Institutes of Health Grant R01 DC00238Thomas and Gerd Perkins Award ProfessorshipAlfred P Sloan Foundation Instrumentation GrantJohn F. and Virginia B. Taplin Award in Health Sciences and TechnologyNational Institutes of Health/National Institute of Deafness and Other Communication DisordersNational Institutes of Health/National Institute of Deafness and Other Communication Disorders Grant PO1 DC0011

Tuning catalysis by surface-deposition of elements on oxidation catalysts via atomic layer deposition

Based on the concept that most reaction steps proceed only at the surface layer of a bulk catalyst, the catalytic impact of the surface-modification with POx, BOx, and MnOx in the selective oxidation of ethane, propane, and n-butane is systematically studied. Three different promoter elements are deposited as a sub-monolayer on the surface of oxidation catalysts with high dispersion by sequential and self-limiting reactions at the solid-gas interface, using atomic layer deposition. Oxygenate and olefin selectivities are tuned by the surface deposition of POx and BOx, leading to improved product yields. The mixed metal oxide MoVTeNbOx is used as a case study to demonstrate the effect of the modification in different reactions with yield improvements of up to 24% in the propane oxidation towards acrylic acid. It is shown that the beneficial performance is related to a change in surface composition, a modification in the electronic properties of the redox active element vanadium, and a decrease in acidity. A comparative study considering several bulk catalysts and deposited elements revealed further promoting effects for different oxidation catalysts. In particular, the deposition of POx on V-containing oxides suppresses COx formation. Precisely adjusted surface modifications leading to enhanced product yields demonstrate the potential of atomic layer deposition as a powerful tool for tuning catalytic properties of bulk catalysts

A bovine lymphosarcoma cell line infected with theileria annulata exhibits an irreversible reconfiguration of host cell gene expression

Theileria annulata, an intracellular parasite of bovine lymphoid cells, induces substantial phenotypic alterations to its host cell including continuous proliferation, cytoskeletal changes and resistance to apoptosis. While parasite induced modulation of host cell signal transduction pathways and NFκB activation are established, there remains considerable speculation on the complexities of the parasite directed control mechanisms that govern these radical changes to the host cell. Our objectives in this study were to provide a comprehensive analysis of the global changes to host cell gene expression with emphasis on those that result from direct intervention by the parasite. By using comparative microarray analysis of an uninfected bovine cell line and its Theileria infected counterpart, in conjunction with use of the specific parasitacidal agent, buparvaquone, we have identified a large number of host cell gene expression changes that result from parasite infection. Our results indicate that the viable parasite can irreversibly modify the transformed phenotype of a bovine cell line. Fifty percent of genes with altered expression failed to show a reversible response to parasite death, a possible contributing factor to initiation of host cell apoptosis. The genes that did show an early predicted response to loss of parasite viability highlighted a sub-group of genes that are likely to be under direct control by parasite infection. Network and pathway analysis demonstrated that this sub-group is significantly enriched for genes involved in regulation of chromatin modification and gene expression. The results provide evidence that the Theileria parasite has the regulatory capacity to generate widespread change to host cell gene expression in a complex and largely irreversible manner

Signal Transmission in the Auditory System

Contains table of contents for Section 3, an introduction, and reports on seven research projects.National Institutes of Health Grant 5 R01 DC00194National Institutes of Health Grant P01 DC00119National Institutes of Health Grant F32 DC00073National Institutes of Health Grant 5 R01 DC00473National Institutes of Health Grant 2 R01 DC00238National Institutes of Health Grant 2 R01 DC00235National Institutes of Health Grant 5 P01 DC00361National Institutes of Health Grant T32 DC00006Whitaker Health Sciences Fun

Transcriptional Analysis of Murine Macrophages Infected with Different Toxoplasma Strains Identifies Novel Regulation of Host Signaling Pathways

Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts.National Institutes of Health (U.S.) (R01-AI080621)New England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (Developmental Grant AIO57159)Pew Charitable Trusts (Biomedical Scholars Program)Robert A. Swanson Career Development awardThe Knights Templar Eye Foundation, Inc.Pre-Doctoral Grant in the Biological Sciences (5-T32-GM007287-33)Cleo and Paul Schimmel Foundatio

Signal Transmission in the Auditory System

Contains table of contents for Section 3, an introduction and reports on six research projects.National Institutes of Health Grant R01-DC-00194-11National Institutes of Health Grant P01-DC00119 Sub-Project 1National Institutes of Health Grant F32-DC00073-2National Institutes of Health Contract P01-DC00119National Institutes of Health Grant R01-DC00238National Institutes of Health Gramt R01-DC00473National Institutes of Health Grant P01-DC00119National Institutes of Health Grant T32-DC00038PNational Institutes of Health Grant P01-DC00361National Institutes of Health Grant 2RO1 DC00235National Institutes of Health Contract NO1-DC2-240

The microwave cavity perturbation technique for contact-free and in situ electrical conductivity measurements in catalysis and materials science

We have developed a noncontact method to probe the electrical conductivity and complex permittivity of single and polycrystalline samples in a flow-through reactor in the temperature range of 20–500 °C and in various gas atmospheres. The method is based on the microwave cavity perturbation technique and allows the simultaneous measurement of microwave conductivity, permittivity and of the catalytic performance of heterogeneous catalysts without any need for contacting the sample with electrodes. The sensitivity of the method towards changes in bulk properties was proven by the investigation of characteristic first-order phase transitions of the ionic conductor rubidium nitrate in the temperature range between 20 and 320 °C, and by studying the temperature dependence of the complex permittivity and conductivity of a niobium(V)-doped vanadium-phosphorous-oxide catalyst for the selective oxidation of n-butane to maleic anhydride. Simultaneously, the catalytic performance was probed by on line GC analysis of evolving product gases making the technique a real in situ method enabling the noninvasive investigation of electronic structure–function relationships

Signal Transmission in the Auditory System

Contains table of contents for Section 3, an introduction and reports on five research projects.National Institutes of Health Grant R01-DC-00194National Institutes of Health Grant P01-DC-00119Charles S. Draper Laboratory Contract DL-H-496015National Institutes of Health Grant R01 DC00238National Institutes of Health Grant R01-DC02258National Institutes of Health Grant T32-DC00038National Institutes of Health Grant RO1 DC00235National Institutes of Health Grant P01-DC00361National Institutes of Health Contract N01-DC-6-210