New Indenylidene‐Schiff Base‐Ruthenium Complexes for Cross‐Metathesis and Ring‐Closing Metathesis

We here report on the stability and catalytic activity of new indenylidene‐Schiff base‐ruthenium complexes 3a – f through representative cross‐metathesis (CM) and ring‐closing metathesis (RCM) reactions. Excellent activity of the new complexes was found for the two selected RCM reactions; prominent conversion was obtained compared to the commercial Hoveyda–Grubbs catalyst 2 . Moreover, excellent results were obtained for a standard CM reaction. Higher conversions were achieved with one of the indenylidene catalysts compared with Hoveyda–Grubbs catalyst. Unexpectedly, an isomerization reaction was observed during the CM reaction of allylbenzene. To the best of our knowledge, isomerization reactions in this model CM reaction in closed systems have never been described using first generation catalysts, including the Hoveyda–Grubbs catalyst. The first model CM reactions as well as the RCM reactions have been monitored using ¹H NMR. The course of the CM reaction of 3‐phenylprop‐1‐ene ( 8 ) and cis‐1,4‐diacetoxybut‐2‐ene ( 9 ) was monitored by GC. The isomerization reaction was studied by means of GC‐mass spectrometry and in situ IR spectroscopy. All catalysts were structurally characterized by means of ¹H, ¹³C, and ³¹P NMR spectroscopy.     

Exergy: its potential and limitations in environmental science and technology

New technologies, either renewables-based or not, are confronted with both economic and technical constraints. Their development takes advantage of considering the basic laws of economics and thermodynamics. With respect to the latter, the exergy concept pops up. Although its fundamentals, that is, the Second Law of Thermodynamics, were already established in the 1800s, it is only in the last years that the exergy concept has gained a more widespread interest in process analysis, typically employed to identify inefficiencies. However, exergy analysis today is implemented far beyond technical analysis; it is also employed in environmental, (thermo)economic, and even sustainability analysis of industrial systems. Because natural ecosystems are also subjected to the basic laws of thermodynamics, it is another subject of exergy analysis. After an introduction on the concept itself, this review focuses on the potential and limitations of the exergy conceptin (1) ecosystem analysis, utilized to describe maximum storage and maximum dissipation of energy flows (2); industrial system analysis: from single process analysis to complete process chain analysis (3); (thermo)economic analysis, with extended exergy accounting; and (4) environmental impact assessment throughout the whole life cycle with quantification of the resource intake and emission effects. Apart from technical system analysis, it proves that exergy as a tool in environmental impact analysis may be the most mature field of application, particularly with respect to resource and efficiency accounting, one of the major challenges in the development of sustainable technology. Far less mature is the exergy analysis of natural ecosystems and the coupling with economic analysis, where a lively debate is presently going on about the actual merits of an exergy-based approach.     

Direct-on-barrier copper electroplating on ruthenium from the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide

The "direct-on-barrier" electroplating of copper on ruthenium from a 1 mol dm⁻³ solution of CuCl in the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide, [C₂mim][N(CN)₂], is reported. Continuous layers of copper with a preferential Cu(111) orientation were obtained from this electrolyte. The copper coatings were investigated by top view scanning electron microscopy (SEM), X-ray diffraction (XRD), and focused ion beam transmission electron microscopy (FIB-TEM). The nucleation density was both theoretically and experimentally evaluated by the Scharifker-Hills model and transmission electron microscopy, respectively. The direct plating of copper on resistive substrates for advanced interconnects and package is a promising new application of ionic liquids.     

Synthesis and in vitro evaluation of alpha-GalCer epimers

alpha-GalCer (also known as KRN7000) is an immunomodulatory glycolipid that is known to potently activate invariant natural killer T (NKT) cells upon CD1d-mediated stimulation. Because Th1 and Th2 cytokines, which are released after alpha-GalCer presentation, antagonize each other's effects, alpha-GalCer analogues that induce a biased Th1/Th2 response are highly awaited. In this context, we report the synthesis and in vitro evaluation of alpha-Gal-D-xylo-Cer and two alpha-Gal-L-lyxo-Cer analogues, one with the natural acyl chain, the other with a truncated chain.     

Reduction of Furan Formation by High-Pressure High-Temperature Treatment of Individual Vegetable Purées

The present study addressed the need for furan mitigation measures at the level of food production, where the effects of extrinsic (process-related) and intrinsic (product-related) properties on furan formation in vegetable-based systems were investigated. For the first time in the literature, the effect of high-pressure high-temperature (HPHT) processing on the formation of furan was demonstrated. HPHT processing was proven to be an interesting alternative for furan reduction in vegetable-based systems, when aiming for sterilization intensities. Following HPHT treatment, the furan concentrations of a wide range of individual vegetable purées dropped to levels close to the analytical limits (1–2 ng/g purée). A higher processing cost might limit the use of HPHT processing to high-value added products, which means that for many other conduction-heated food products, conventional heating would remain the standard technology. As a first step towards control of furan formation in the latter products, a mixed model regression was used to identify the major precursors in vegetable-based systems. Significant correlations were observed for vitamin C and sugars, which were attributed to the efficiency of the conversion and high concentrations, respectively. Next to furan, the HPHT- and thermally treated purées were analyzed for 2- and 3-methylfuran, which are likely to undergo the same metabolic fate as furan. For most of the vegetables tested, the total amount of methylfuran found in the thermally treated purées could not be ignored. Similarly to furan, there was a clear reduction in the concentrations found in the HPHT-treated purées.     

Mixed species biofilms of Listeria monocytogenes and Lactobacillus plantarum show enhanced resistance to benzalkonium chloride and peracetic acid

We investigated the formation of single and mixed species biofilms of Listeria monocytogenes strains EGD-e and LR-991, with Lactobacillus plantarum WCFS1 as secondary species, and their resistance to the disinfectants benzalkonium chloride and peracetic acid. Modulation of growth, biofilm formation, and biofilm composition was achieved by addition of manganese sulfate and/or glucose to the BHI medium. Composition analyses of the mixed species biofilms using plate counts and fluorescence microscopy with dual fluorophores showed that mixed species biofilms were formed in BHI (total count, 8-9 log₁₀ cfu/well) and that they contained 1-2 log₁₀ cfu/well more L. monocytogenes than L. plantarum cells. Addition of manganese sulfate resulted in equal numbers of both species (total count, 8 log₁₀ cfu/well) in the mixed species biofilm, while manganese sulfate in combination with glucose, resulted in 1-2 log₁₀ more L. plantarum than L. monocytogenes cells (total count, 9 log₁₀ cfu/well). Corresponding single species biofilms of L. monocytogenes and L. plantarum contained up to 9 log₁₀ cfu/well. Subsequent disinfection treatments showed mixed species biofilms to be more resistant to treatments with the selected disinfectants. In BHI with additional manganese sulfate, both L. monocytogenes strains and L. plantarum grown in the mixed species biofilm showed less than 2 log₁₀ cfu/well inactivation after exposure for 15 min to 100 μg/ml benzalkonium chloride, while single species biofilms of both L. monocytogenes strains showed 4.5 log₁₀ cfu/well inactivation and single species biofilms of L. plantarum showed 3.3 log₁₀ cfu/well inactivation. Our results indicate that L. monocytogenes and L. plantarum mixed species biofilms can be more resistant to disinfection treatments than single species biofilms.     

MODELING DISSOLVED OXYGEN CONCENTRATION FOR OPTIMIZING AERATION SYSTEMS AND REDUCING OXYGEN CONSUMPTION IN ACTIVATED SLUDGE PROCESSES: A REVIEW

Aeration accounts for 30% to 75% of the total energy consumption in activated sludge processes (ASPs). This percentage can be significantly reduced since most aeration systems are not optimized for unsteady influent flow rates and oxygen requirements. Reconfiguration, replacement, and the application of optimal dissolved oxygen (DO) control strategies for current aeration systems within the facility and model-based optimization of DO in wastewater treatment plants can lead to impressive increased energy efficiency and savings and improved stability of the system. These measures increase the operational lifetime of the aeration equipment and improve effluent and activated sludge quality. This article provides a review of two critical nonlinear time-varying parameters that characterize the DO concentration dynamics in an ASP: the oxygen uptake rate (OUR), related to microorganism activity, and the volumetric oxygen mass transfer function, represented by the oxygen transfer rate (OTR). Second, the physico-chemical, geometric, and dynamic factors and aerator type affecting the oxygen mass transfer coefficient (K _L a) are thoroughly discussed. The article concludes with model-based optimization, explaining the usefulness of accurate DO models in wastewater treatment, and provides examples for plant-wide or water chain cycle–focused optimizations.     

The Saccharomyces cerevisiae alcohol acetyl transferase Atf1p is localized in lipid particles

The yeast alcohol acetyl transferase I, Atf1p, is responsible for the major part of volatile acetate ester production in fermenting Saccharomyces cerevisiae cells. Some of these esters, such as ethyl acetate and isoamyl acetate, are important for the fruity flavours of wine, beer and other fermented beverages. In order to reveal the subcellular localization of Atf1p and further unravel the possible physiological role of this protein, ATF1::GFP fusion constructs were overexpressed in brewer's yeast. The transformant strain showed a significant increase in acetate ester formation, similar to that of an ATF1 overexpression strain, indicating that the Atf1p-GFP fusion protein was active. UV fluorescence microscopy revealed that the fusion protein was localized in small, sphere-like organelles. These organelles could be selectively stained by the fluorescent dye Nile red, indicating that they contained high amounts of neutral lipids and/or sterols, a specific characteristic of yeast lipid particles. Purification of lipid particles from wild type and ATF1 deletion cells confirmed that the Atf1p-GFP fusion protein was located in these organelles. Furthermore, a clear alcohol acetyl transferase activity could be measured in the purified lipid particles of both wild type and transformed cells. The localization of Atf1p in lipid particles may indicate that Atf1p has a specific role in the lipid and/or sterol metabolism that takes place in these particles.     

Dyadic spatial resolution reduction transcoding for H.264/AVC

In this paper, we examine spatial resolution downscaling transcoding for H.264/AVC video coding. A number of advanced coding tools limit the applicability of techniques, which were developed for previous video coding standards. We present a spatial resolution reduction transcoding architecture for H.264/AVC, which extends open-loop transcoding with a low-complexity compensation technique in the reduced-resolution domain. The proposed architecture tackles the problems in H.264/AVC and avoids visual artifacts in the transcoded sequence, while keeping complexity significantly lower than more traditional cascaded decoder–encoder architectures. The refinement step of the proposed architecture can be used to further improve rate-distortion performance, at the cost of additional complexity. In this way, a dynamic-complexity transcoder is rendered possible. We present a thorough investigation of the problems related to motion and residual data mapping, leading to a transcoding solution resulting in fully compliant reduced-size H.264/AVC bitstreams.