Polyoxyethylene di-phosphonates as efficient dispersing polymers for aqueous suspensions

Polyoxyethylenes having a di-phosphonate functional group at one of their chain ends strongly adsorb on calcium carbonate particles in aqueous colloidal suspensions. An enhanced colloidal stability of such suspensions results with a concomitant drastic reduction of the viscosity of concentrated aqueous suspensions. The viscosity of a 20 wt % CaCO₃ colloidal suspension in water could be lowered to 2 mPa · s with low concentrations of polymer. The adsorption and viscosity reduction were studied as a function of the chemical nature of the end chain group and the polymer molecular weight. The di-phosphonate group was found the most efficient anionic group when associated with a polyoxyethylene of polymerization degree larger than 20. The main features of this di-block architecture of the polymer are discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2545–2555, 1997     

Potential Applications of Enzymes in Waste Treatment

The implementation of increasingly stringent standards for the discharge of wastes into the environment has necessitated the need for the development of alternative waste treatment processes. A review of research directed toward developing enzymatic treatment systems for solid, liquid and hazardous wastes is presented. A large number of enzymes from a variety of different plants and microorganisms have been reported to play an important role in an array of waste treatment applications. Enzymes can act on specific recalcitrant pollutants to remove them by precipitation or transformation to other products. They also can change the characteristics of a given waste to render it more amenable to treatment or aid in converting waste material to value-added products. Before the full potential of enzymes may be realized, it is recommended that a number of issues be addressed in future research endeavors including the identification and characterization of reaction by-products, the disposal of reaction products and reduction of the cost of enzymatic treatment. © 1997 SCI.     

“Dark” Singlet Oxygenation of Hydrophobic Substrates in Environmentally Friendly Microemulsions

The molybdate‐catalyzed “dark” singlet oxygenation of hydrophobic compounds with hydrogen peroxide proceeds efficiently with low catalyst loadings (10 ^–3 mol %) in chlorine‐free w/o microemulsions. These micro‐heterogeneous systems are composed of sodium dodecyl sulfate (SDS)/n‐butanol/water/organic phase, the latter being either a ”green” solvent such as ethyl acetate or a liquid substrate, such as α‐terpinene or β‐citronellol. Very high reactor yields with improved product/SDS ratio can be obtained for the ”dark” singlet oxygenation of such liquid substrates.     

Modeling of mass transfers between food simulants and treated plasticized PVC

PVC is often used in food packaging and blood bags. This study concerns mass transfers between plasticized PVC, having been subjected to a treatment, and liquid food or food simulants. The treatment reduces the diffusion of the plasticizer and the influence of some factors of this processing are investigated. A mathematical model, able to simulate these mass transfers and to quantify the treatment parameters, is proposed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 49–58, 1999     

Continuous fixed bed biosorption of Cu2+ ions: application of a simple two parameter mathematical model

Biomass from two fungi of the Mucorales order, laboratory cultured and immobilised Rhizopus arrhizus, and industrial waste Mucor miehei, was tested for capacity to adsorb copper from solution in batch and continuous‐flow column systems. Maximum uptake levels were c 400 and 300 mmol g⁻¹ (dry weight) respectively. Immobilisation of Rhizopus arrhizus in polyvinyl formal to cell loadings of 60% (w/w) did not diminish metal uptake levels. In continuous‐flow columns both biosorbents adsorbed copper to levels equal or approaching the batch uptake values. Column breakthrough curves were fitted to a two parameter model and each of the parameters, σ and t₀ , were linearly correlated with column operating parameters. Predicted breakthrough curves agreed closely with experimental values. © 1999 Society of Chemical Industry     

Etifoxine Restores Mitochondrial Oxidative Phosphorylation and Improves Cognitive Recovery Following Traumatic Brain Injury

The opening of the mitochondrial permeability transition pore (mPTP) has emerged as a pivotal event following traumatic brain injury (TBI). Evidence showing the impact of the translocator protein (TSPO) over mPTP activity has prompted several studies exploring the effect of TSPO ligands, including etifoxine, on the outcome of traumatic brain injury (TBI). Mitochondrial respiration was assessed by respirometry in isolated rat brain mitochondria (RBM) by measurements of oxidative phosphorylation capacity (OXPHOS). The addition of calcium to RBM was used to induce mitochondrial injury and resulted in significant OXPHOS reduction that could be reversed by preincubation of RBM with etifoxine. Sensorimotor and cognitive functions were assessed following controlled cortical impact and compared in vehicle and etifoxine-treated animals. There was no difference between the vehicle and etifoxine groups for sensorimotor functions as assessed by rotarod. In contrast, etifoxine resulted in a significant improvement of cognitive functions expressed by faster recovery in Morris water maze testing. The present findings show a significant neuroprotective effect of etifoxine in TBI through restoration of oxidative phosphorylation capacity associated with improved behavioral and cognitive outcomes. Since etifoxine is a registered drug used in common clinical practice, implementation in a phase II study may represent a reasonable step forward.     

Konformation und Rotationsbarrieren substituierter Glyoxylsäureamide

Conformation and Rotation Barriers of Substituted Glyoxylic Acid Amides Semiempirical calculations predict an orthogonal orientation of the carbonyl groups in tertiary glyoxylic acid amides, which is in good agreement with an X-ray structure analysis of 5 . Due to the influence of the α-carbonyl group, the rotation barrier in the substituted glyoxylic acid amides 2a–d, 3a, 3b , and 4–6 (ΔG^#_c = 84–92 kJ mol⁻¹) is about 10 kJ/mol higher than in simple acid amides, as was found by dynamic NMR line shape analysis.     

Phenolic Substances in Beer: Structural Diversity,Reactive Potential and Relevance for Brewing Process and Beer Quality

For the past 100 years, polyphenol research has played a central role in brewing science. The class of phenolic substances comprises simple compounds built of 1 phenolic group as well as monomeric and oligomeric flavonoid compounds. As potential anti‐ or prooxidants, flavor precursors, flavoring agents and as interaction partners with other beer constituents, they influence important beer quality characteristics: flavor, color, colloidal, and flavor stability. The reactive potential of polyphenols is defined by their basic chemical structure, hydroxylation and substitution patterns and degree of polymerization. The quantitative and qualitative profile of phenolic substances in beer is determined by raw material choice. During the malting and brewing process, phenolic compounds undergo changes as they are extracted or enzymatically released, are subjected to heat‐induced chemical reactions or are precipitated with or adsorbed to hot and cold trub, yeast cells and stabilization agents. This review presents the current state of knowledge of the composition of phenolic compounds in beer and brewing raw materials with a special focus on their fate from raw materials throughout the malting and brewing process to the final beer. Due to high‐performance analytical techniques, new insights have been gained on the structure and function of phenolic substance groups, which have hitherto received little attention. This paper presents important information and current studies on the potential of phenolics to interact with other beer constituents and thus influence quality parameters. The structural features which determine the reactive potential of phenolic substances are discussed.