Microstructure of SrTiO3 Boundary-Layer Capacitor Material

SiTiO₃ capacitor material with indiffused Bi₂O₃ was studied using SEM, ESCA combined with Ar⁺ ion-etching, and TEM equipped with EDX. The apparent thickness of a second-phase layer observed with SEM was found to be influenced by in-depth effects. ESCA and TEM results show that only a 10- to 100-nm thick layer of second phase is present between the SrTiO₃ grains. In addition, it was found with TEM that the outer part of each grain contained Bi (at most 2 at.%), representing a diffusion layer. These results have implications for the boundary-layer model proposed to explain the dielectric properties .     

URBAN PROBLEM DISCOURSES: UNDERSTANDING THE DISTINCTIVENESS OF CITIES

Despite the insistence in interpretive policy analysis that the discursive construction of problems must be understood in terms of their historical and spatial context, it remains an open question how cities provide such a context. We argue that cities as a distinct form of sociation enable certain (discursive) actions, while restricting others. Taking both the interest of interpretive policy analysis in the social construction of political reality and holistic concepts of approaching the distinctiveness of cities as starting points, we scrutinize how the cities of Frankfurt/Main, Dortmund, Birmingham, and Glasgow provide distinct contexts for the construction of local policy problems. Based on an inquiry into urban discourses we ask, first, how problematizations involve locally specific attributions of problem causes and responsibilities for problem solving and, second, how this is related to a locally distinct understanding of the city's past, present, and future.     

Achievements and trends of solid oxide fuel cells in clean energy field: a perspective review

The main concerns in the world today, especially in the energy field, are subjected to clean, efficient, and durable sources of energy. These three aspects are the main goals that scientist are paying attention to. However, the various types of energy resources include fossil and sustainable ones, but still some challenges are chasing these kinds from energy conversion, storage, and efficiency. Hence, the most reliable and considered energy resource nowadays is the utilized one which is as highly efficient, clean, and everlasting as possible. So, in this review, an attempt is made to highlight one of the promising types as a clean and efficient energy resource. Solid oxide fuel cell (SOFC) is the most efficient type of the fuel cell types involved with hydrogen and hydrocarbon-based fuels, especially when it works with combined heat and power (CHP). The importance of this type is due to its nature of work as conversion tool from chemical to electrical for generation of power without noise, pollution, and can be safely handled.     

Characterisation of the Lactobacillus community in traditional Karst ewe's cheese

Ewe's cheese, produced in the Slovenian Karst region, was analysed for its lactobacilli population. Biochemical fingerprinting with PhenePlate™ LB grouped lactobacilli in 16 distinct PhP types. One representative from each PhP type was further analysed. Members of Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus curvatus, and Lactobacillus brevis species were determined phenotypically. The genus-specific DNA band was amplified with all PhP representatives, whereas species-specific polymerase chain reaction efficiently determined only L. paracasei and L. brevis. Lactobacilli were highly to moderate sensitive to six antibiotics, and resistant to vancomycin. From halo formation in the agar spot method, indicators exerted a promising level of sensitivity for antimicrobials, produced by test microorganisms. Lactobacilli from Karst ewe's cheese offer a remarkable reservoir of 'natural' microbes.     

DIFFUSION IN NON-IONIC AND IONIC POLYMER SOLUTIONS: EFFECTS OF SHEAR RATE AND POLYMER CONCENTRATION

Diffusion coefficients for ferricyanide ions in aqueous polymer solutions have been calculated from laminar flow mass transfer data obtained in a concentric annulus apparatus by the electrochemical voltammetric method. The electrolyte solutions containing one to five percent polyvinyl alcohol or polyacrylic acid were pumped through the annulus. Flow was longitudinal, and the shear rate ranged from 7 to 800 s-1 The diffusion coefficient for ferricyanide in the polymer solutions depended on polymer concentration in a different way for the non-ionic (polyvinyl alcohol) solutions compared to the polyelectrolyte (polyacrylic acid) solutions. Over the range of concentrations studied, the diffusion coefficient as a function of polymer concentration for polyacrylic acid solutions reached a minimum, increased to a maximum, and then decreased slightly.The polyvinyl alcohol data showed minimum and maximum but no decrease, and the minimum occurred at a higher polymer concentration. For each type of solution, the diffusion coefficient decreased from five to twenty percent as the shear rate was increased from 100 to 800 s-1.The diffusion data can be related to polymer molecule uncoiling and stretching in the flowing solution and to solvation of the molecules present.     

RAPID DETECTION OF OUTBREAK ESCHERICHIA COLI O157 AND SALMONELLA ON ALFALFA SPROUTS BY IMMUNOMAGNETIC CAPTURE AND TIME‐RESOLVED FLUORESCENCE1

Commercially available alfalfa seeds were inoculated with low levels (～ 4 CFU/g) of pathogenic bacteria and sprouted at 25C. At 48 h, the spent irrigation water and sprouts were separately transferred to brain heart infusion (BHI) broth and enriched for 4 h at 37C and 160 rpm. Specific immunomagnetic beads (IMB) were then applied to capture the E. coli O157 or Salmonella in the enriched media. Separation and concentration of captured pathogens were achieved using magnetic particle concentrators (MPC). IMB captured E. coli O157:H7 and Salmonella spp. then formed sandwiched complexes with europium (Eu) labeled anti‐E. coli O157 antibodies and samarium (Sm) labeled anti‐Salmonella antibodies, respectively. After washing the complexes, the lanthanide labels were extracted out from the complexes by specific chelators to form strongly fluorescent Eu‐ and Sm‐chelates. The specific time‐resolved fluorescence (TRF) associated with Eu or Sm was measured to estimate the extent of capture of the E. coli O157 and Salmonella, respectively. The results indicated that the approach could detect E. coli O157 and many Salmonella spp. from spent irrigation water or sprouts grown from contaminated seeds. Nontargeted bacteria, e.g., native microflora present on the untreated seeds and inoculated Aeromonas and Citrobacter, exhibited no crossreactivity and counts were not significantly different from background fluorescence of the IMB alone. Since pathogen detection was achieved within 6 h, the assay could detect contamination levels as low as 4 CFU/g of seeds and it showed no cross‐reactivity with nonpathogenic microflora present on the sprouts, the developed methodology could be used as a rapid, sensitive and specific screening process for E. coli O157 and Salmonella spp. in sprouts and their irrigation water.     

Stem cells in intervertebral disc regeneration–more talk than action?

Pain and lifestyle changes are common consequences of intervertebral disc degeneration (IVDD) and affect a large part of the aging population. The stemness of cells is exploited in the field of regenerative medicine as key to treat degenerative diseases. Transplanted cells however often face delivery and survival challenges, especially in tissues with a naturally harsh microniche environment such as the intervertebral disc. Recent interest in the secretome of stem cells, especially cargo protected from microniche-related decay as frequently present in degenerating tissues, provides new means of rejuvenating ailing cells and tissues. Exosomes, a type of extracellular vesicles with purposeful cargo gained particular interest in conveying stem cell related attributes of rejuvenation, which will be discussed here in the context of IVDD.