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- ItemDNA and RNA extraction and quantitative real-time PCR-based assays for biogas biocenoses in an interlaboratory comparison(Basel : MDPI, 2016) Lebuhn, Michael; Derenkó, Jaqueline; Rademacher, Antje; Helbig, Susanne; Munk, Bernhard; Pechtl, Alexander; Stolze, Yvonne; Prowe, Steffen; Schwarz, Wolfgang H.; Schlüter, Andreas; Liebl, Wolfgang; Klocke, MichaelFive institutional partners participated in an interlaboratory comparison of nucleic acid extraction, RNA preservation and quantitative Real-Time PCR (qPCR) based assays for biogas biocenoses derived from different grass silage digesting laboratory and pilot scale fermenters. A kit format DNA extraction system based on physical and chemical lysis with excellent extraction efficiency yielded highly reproducible results among the partners and clearly outperformed a traditional CTAB/chloroform/isoamylalcohol based method. Analytical purpose, sample texture, consistency and upstream pretreatment steps determine the modifications that should be applied to achieve maximum efficiency in the trade-off between extract purity and nucleic acid recovery rate. RNA extraction was much more variable, and the destination of the extract determines the method to be used. RNA stabilization with quaternary ammonium salts was an as satisfactory approach as flash freezing in liquid N2. Due to co-eluted impurities, spectrophotometry proved to be of limited value for nucleic acid qualification and quantification in extracts obtained with the kit, and picoGreen® based quantification was more trustworthy. Absorbance at 230 nm can be extremely high in the presence of certain chaotropic guanidine salts, but guanidinium isothiocyanate does not affect (q)PCR. Absolute quantification by qPCR requires application of a reliable internal standard for which correct PCR efficiency and Y-intercept values are important and must be reported.
- ItemSwitchable Adhesion Surfaces with Enhanced Performance Against Rough Counterfaces(Basel : MDPI, 2016) Prieto-López, Lizbeth; Williams, JohnIn a recent study, we demonstrated that the pressurization of micro-fluidic features introduced in the subsurface of a soft polymer can be used to actively modify the magnitude of the adhesion to a harder counterface by changing its waviness or long wavelength undulations. In that case, both contacting surfaces had very smooth finishes with root-mean-square roughnesses of less than 20 nm. These values are far from those of many engineering surfaces, which usually have a naturally occurring roughness of between ten and a hundred times this value. In this work, we demonstrate that appropriate surface features, specifically relatively slender “fibrils”, can enhance the ability of a such a soft surface to adhere to a hard, but macroscopically rough, counterface, while still maintaining the possibility of switching the adhesion force from one level to another. Conversely, stiffer more conical surface features can suppress adhesion even against a smooth counterface. Examples of each form of topography can be found in the natural world.
- ItemMercury plumes in the global upper troposphere observed during flights with the CARIBIC observatory from may 2005 until june 2013(Basel : MDPI, 2014) Slemr, Franz; Weigelt, Andreas; Ebinghaus, Ralf; Brenninkmeijer, Carl; Baker, Angela; Schuck, Tanja; Rauthe-Schöch, Armin; Riede, Hella; Leedham, Emma; Hermann, Markus; van Velthoven, Peter; Oram, David; O'Sullivan, Debbie; Dyroff, Christoph; Zahn, Andreas; Ziereis, HelmutTropospheric sections of flights with the CARIBIC (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrumented Container) observatory from May 2005 until June 2013, are investigated for the occurrence of plumes with elevated Hg concentrations. Additional information on CO, CO2, CH4, NOy, O3, hydrocarbons, halocarbons, acetone and acetonitrile enable us to attribute the plumes to biomass burning, urban/industrial sources or a mixture of both. Altogether, 98 pollution plumes with elevated Hg concentrations and CO mixing ratios were encountered, and the Hg/CO emission ratios for 49 of them could be calculated. Most of the plumes were found over East Asia, in the African equatorial region, over South America and over Pakistan and India. The plumes encountered over equatorial Africa and over South America originate predominantly from biomass burning, as evidenced by the low Hg/CO emission ratios and elevated mixing ratios of acetonitrile, CH3Cl and particle concentrations. The backward trajectories point to the regions around the Rift Valley and the Amazon Basin, with its outskirts, as the source areas. The plumes encountered over East Asia and over Pakistan and India are predominantly of urban/industrial origin, sometimes mixed with products of biomass/biofuel burning. Backward trajectories point mostly to source areas in China and northern India. The Hg/CO2 and Hg/CH4 emission ratios for several plumes are also presented and discussed.
- ItemThe role of bioenergy in enhancing energy, food and ecosystem sustainability based on societal perceptions and preferences in Asia(Basel : MDPI, 2016) Acosta, Lilibeth A.; Magcale-Macandog, Damasa B.; Kavi Kumar, K.S.; Cui, Xuefeng; Eugenio, Elena A.; Macandog, Paula Beatrice M.; Salvacion, Arnold R.; Eugenio, Jemimah Mae A.This paper discussed the analysis of the survey on sustainability of bioenergy conducted in the Philippines, India and China. It acquired general perceptions of the people by asking them (a) specific questions about their level of familiarity with bioenergy; (b) relationship of their work to bioenergy; and (c) their opinion on contribution of various feedstock on the economy and impact of bioenergy production on food security. In addition to these questions, we estimated preference weights of various feedstock based on the conjoint choices on bioenergy’s contribution to social stability, social welfare and ecological balance. The estimates revealed significant trade-offs not only among these three dimensions of sustainability but also the relative importance of energy security, food security and ecosystem capacity to other economic, social and environmental objectives. The types of first generation feedstock that are currently used for biofuel production in the respective countries and those that offer alternative household use are perceived as important to the economy and preferred bioenergy feedstock. Based on the results of the study, the preferred role of bioenergy for sustainable development reflects the social and economic concerns in the respective Asian countries, e.g., energy security in China, food security in India, and ecosystem degradation in the Philippines.
- ItemCatalytic Performance of Lanthanum Vanadate Catalysts in Ammoxidation of 2-Methylpyrazine(Basel : MDPI, 2016) Kalevaru, Venkata; Dhachapally, Naresh; Martin, AndreasThe influence of reaction conditions on the catalytic performance of lanthanum vanadate (La0.1V0.9Ox) catalyst in the ammoxidation of 2-methylpyrazine (MP) to 2-cyanopyarazine (CP) has been investigated. This novel catalytic material exhibited remarkably good performance with very high space-time-yields (STY) of CP. The reaction parameters such as the effect of temperature, gas hourly space velocity (GHSV) and all other reaction variables (e.g., NH3, air, and MP feed rates) on the catalytic performance were explored and optimized. For example, an increase in MP feed rate from 2 to >16 mmol/h led to decreased conversion of MP but increased the STY of CP significantly. Optimal performance was achieved when the reaction temperature was 420 °C and the molar ratio of 2-MP, ammonia, air, H2O and N2 in the feed gas was set to 1:7:26:13:22. Under these optimal reaction conditions, the catalyst showed a MP conversion of ~100%, CP selectivity of 86%, and STY of >500 gCP/(kgcat∙h). On the other hand, the formation of pyrazine (Py) as a by-product was found to be high when the NH3:MP ratio was lower at increased contact time. This suggests possible differences in the reaction mechanism pathways with respect to feed composition over La0.1V0.9Ox catalysts.
- ItemBimetallic Catalysts Containing Gold and Palladium for Environmentally Important Reactions(Basel : MDPI, 2016) Alshammari, Ahmad; Kalevaru, Venkata Narayana; Martin, AndreasSupported bimetallic nanoparticles (SBN) are extensively used as efficient redox catalysts. This kind of catalysis particularly using SBN has attracted immense research interest compared to their parent metals due to their unique physico-chemical properties. The primary objective of this contribution is to provide comprehensive overview about SBN and their application as promising catalysts. The present review contains four sections in total. Section 1 starts with a general introduction, recent progress, and brief summary of the application of SBN as promising catalysts for different applications. Section 2 reviews the preparation and characterization methods of SBN for a wide range of catalytic reactions. Section 3 concentrates on our own results related to the application of SBN in heterogeneous catalysis. In this section, the oxidation of cyclohexane to adipic acid (an eco-friendly and novel approach) will be discussed. In addition, the application of bimetallic Pd catalysts for vapor phase toluene acetoxylation in a fixed bed reactor will also be highlighted. Acetoxylation of toluene to benzyl acetate is another green route to synthesize benzyl acetate in one step. Finally, Section 4 describes the summary of the main points and also presents an outlook on the application of SBN as promising catalysts for the production of valuable products.
- ItemModeling the shape of ions in pyrite-type crystals(Basel : MDPI, 2014) Birkholz, MarioThe geometrical shape of ions in crystals and the concept of ionic radii are re-considered. The re-investigation is motivated by the fact that a spherical modelling is justified for p valence shell ions on cubic lattice sites only. For the majority of point groups, however, the ionic radius must be assumed to be an anisotropic quantity. An appropriate modelling of p valence ions then has to be performed by ellipsoids. The approach is tested for pyrite-structured dichalcogenides MX2, with chalcogen ions X = O, S, Se and Te. The latter are found to exhibit the shape of ellipsoids being compressed along the <111> symmetry axes, with two radii r
- ItemFloating zone growth of Bi2Sr2Ca2Cu3Oy superconductor(Basel : MDPI, 2016) Maljuk, Andrey; Lin, C.T.The crystal growth of high-temperature oxide superconductors has been hampered by the complexities of these materials and the lack of knowledge of corresponding phase diagrams. The most common crystal growth technique adopted for these materials is the so-called “Flux” method. This method, however, suffers from several drawbacks: (i) crystals are often crucible and flux contaminated; (ii) crystals are difficult to detach from solidified melt; and (iii) crystals are rather small. In most cases, these drawbacks can be overcome by the crucible-free floating zone method. Moreover, this technique is suitable for crystal growth of incongruently melting compounds, and has been thus successfully used to make large single crystals of Bi2Sr2Ca2Cu3Oy superconductor. In this review, the authors summarize the published and their own growth efforts as well as detailed characterization of as-grown and post-growth annealed samples. The optimal growth conditions that allowed one to obtain the large-size, almost single phase and homogeneous in composition Bi2Sr2Ca2Cu3Oy single crystals are presented. The effect of long lasting post-growth heat treatment on both crystal quality and superconducting properties has also been demonstrated.
- ItemProperties of LiGa0.5In0.5Se2: A Quaternary Chalcogenide Crystal for Nonlinear Optical Applications in the Mid-IR(Basel : MDPI, 2016) Isaenko, Ludmila; Yelisseyev, Alexander; Lobanov, Sergei; Vedenyapin, Vitaliy; Krinitsyn, Pavel; Petrov, ValentinLiGaSe2 (LGSe) and LiInSe2 (LISe) are wide band-gap nonlinear crystals transparent in the mid-IR spectral range. LiGa0.5In0.5Se2 (LGISe) is a new mixed crystal, a solid solution in the system LGSe–LISe, which exhibits the same orthorhombic structure (mm2) as the parent compounds in the same time being more technological with regard to the growth process. In comparison with LGSe and LISe its homogeneity range is broader in the phase diagram. About 10% of the Li ions in LGISe occupy octahedral positions (octapores) with coordination number of 3. The band-gap of LGISe is estimated to be 2.94 eV at room temperature and 3.04 eV at 80 K. The transparency at the 0-level extends from 0.47 to 13 µm. LGISe crystals exhibit luminescence in broad bands centered near 1.7 and 1.25 eV which is excited most effectively by band-to-band transition. From the measured principal refractive indices and the fitted Sellmeier equations second-harmonic generation from 1.75 to 11.8 μm (fundamental wavelength) is predicted. The nonlinear coefficients of LGISe have values between those of LGSe and LISe. 6LGISe crystals are considered promising also for detection of thermal neutrons.
- ItemSynthesis and molecular structures of the lowest melting odd- and even-numbered a,b-unsaturated carboxylic acids—(E)-hept-2-enoic acid and (E)-oct-2-enoic acid(Basel : MDPI, 2016) Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian; Peppel, TimThe molecular structures of the two lowest melting odd- and even-numbered α,β-unsaturated carboxylic acids—(E)-hept-2-enoic acid (C7) and (E)-oct-2-enoic acid (C8)—are herein reported. The title compounds were crystallized by slow evaporation of ethanolic solutions at −30 °C. C7 crystallizes in the triclinic space group P1¯ with two molecules in the unit cell and C8 in the monoclinic space group C2/c with eight molecules in the unit cell. The unit cell parameters for C7 are: a = 5.3049(2) Å, b = 6.6322(3) Å, c = 11.1428(5) Å, α = 103.972(3)°, β = 97.542(3)°, γ = 90.104(3)°, and V = 376.92(3) Å3 (T = 150(2) K). The unit cell parameters for C8 are: a = 19.032(10) Å, b = 9.368(5) Å, c = 11.520(6) Å, β = 123.033(11)°, and V = 1721.80(16) Å3 (T = 200(2) K).