Heat pretreatment of oilseeds: effect on oil quality

We studied the effect of seed conditioning via a rapid preheating technique to destroy the activity of oil-degrading enzymes. Rape and sunflower seeds were heated via steaming, oven cooking, infrared, and microwave. After the pretreatment the oil was expelled from the seeds by a screw press and its quality was determined via the analysis of oxidative stability, peroxide value, free fatty acid content, phosphorus, and iron. From the results it was concluded that preheating of the seeds leads to the expected decreased activity of lipase, but nevertheless increased levels of phosphorus and free fatty acids were observed. However, increased levels of phenolic antioxidants markedly improved the oxidative stability of rapeseed oil. From the techniques studied for heating of the seeds, microwave and steaming appeared to be the most suitable techniques. Both methods gave markedly improved oxidative stability, whereas steaming seemed to result in less formation of free fatty acids than microwave heating. Infrared heating led to rapidly burnt seeds and off-flavours.     

The effect of storage of whole potatoes of three cultivars on the patatin and protease inhibitor content; a study using capillary electrophoresis and MALDI-TOF mass spectrometry

The content and biological activity of patatin and the protease inhibitors of molecular size 20–22 kDa present in whole potato tubers were investigated as a function of storage time. The amount of buffer-extractable protein decreased gradually during storage of whole potatoes of the cultivars Bintje and Desiree for 47 weeks whereas, for Elkana, it increased after approximately 25 weeks. The patatin proportion of the extractable protein did not decrease significantly during storage, whereas the proportion of PP_20–22 protease inhibitors decreased. All cultivars contained several different patatin isoforms. Bintje and Desiree showed patatin populations with two masses whereas for Elkana, only one molar mass was found. Patatin isoforms of the three cultivars examined showed no significant differences in stability towards degradation as was concluded from capillary electrophoresis analysis. No inactivation of patatin or protease inhibitors by partial degradation of these proteins was observed using matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF MS), whereas enzyme-activity assays suggested that the biological activity, especially in the cultivar Bintje, decreased markedly at the break of dormancy. © 1999 Society of Chemical Industry     

Sedimentation behavior of mixed solid particles

During the material relocation phase of core-disruptive accidents in sodium-cooled fast reactors, the sedimentation behavior of fragmented debris discharged from the reactor core into the lower plenum region leading to a debris-bed formation is crucial in regard to in-vessel retention and safety concerns. The height of the beds formed may influence both the cooling of the bed from the decay heat in the fuel and the neutronic characteristics. To develop an experimental database of bed formation behavior, a series of experiments using simulant materials, namely, Al₂O₃, ZrO₂, and stainless steel, were performed under gravity-driven discharge of solid particles from a nozzle into a quiescent cylindrical water pool. The bed height was measured for particles of different size, density, and sphericity, and an injection nozzle with varying diameter, injection velocity, and injection height. From these experiments, an empirical correlation was established to predict the bed height for both homogeneous and mixed particles for the different properties. This correlation reproduces reasonably well the experimental trend in bed height with critical factors, which were identified in this and previous experiments.     

A study on inspection schemes in optimal design of control charts for deteriorating processes

The non-uniform inspection scheme obtained by the constant integrated hazard procedure overcomes the uniform scheme economically in optimal design of control charts. The comperative study is generalized in this paper to an optimization problem which looks for the optimal sampling points among all possible sampling schemes. The objective function is simplified here by modelling sequential time intervals as a family of functions of the first sampling interval, which also has been induced by the constant integrated hazard approach. The study demonstrates the model implementation through the economic design of $\overline{X}$ and T²-Hotelling control charts, both under the two widely used process failure mechanisms, that is, Weibull and Chen distributions. A comprehensive numerical investigation illustrates the possibility of existence of sampling schemes which outperform the constant integrated hazard approach and emphasizes the necessity of further investigation into the solution procedure.     

A Degron Blocking Strategy Towards Improved CRL4CRBN Recruiting PROTAC Selectivity**

Small molecules inducing protein degradation are important pharmacological tools to interrogate complex biology and are rapidly translating into clinical agents. However, to fully realise the potential of these molecules, selectivity remains a limiting challenge. Herein, we addressed the issue of selectivity in the design of CRL4^CRBN recruiting PROteolysis TArgeting Chimeras (PROTACs). Thalidomide derivatives used to generate CRL4^CRBN recruiting PROTACs have well described intrinsic monovalent degradation profiles by inducing the recruitment of neo-substrates, such as GSPT1, Ikaros and Aiolos. We leveraged structural insights from known CRL4^CRBN neo-substrates to attenuate and indeed remove this monovalent degradation function in well-known CRL4^CRBN molecular glues degraders, namely CC-885 and Pomalidomide. We then applied these design principles on a previously published BRD9 PROTAC (dBRD9-A) and generated an analogue with improved selectivity profile. Finally, we implemented a computational modelling pipeline to show that our degron blocking design does not impact PROTAC-induced ternary complex formation. We believe that the tools and principles presented in this work will be valuable to support the development of targeted protein degradation.     

Molecular Resolution Nanostructure and Dynamics of the Deep Eutectic Solvent—Graphite Interface as a Function of Potential

Interest in deep eutectic solvents (DESs), particularly for electrochemical applications, has boomed in the past decade because they are more versatile than conventional electrolyte solutions and are low cost, renewable, and non-toxic. The molecular scale lateral nanostructures as a function of potential at the solid–liquid interface—critical design parameters for the use of DESs as electrochemical solvents—are yet to be revealed. In this work, in situ amplitude modulated atomic force microscopy complemented by molecular dynamics simulations is used to probe the Stern and near-surface layers of the archetypal and by far most studied DES, 1:2 choline chloride:urea (reline), at the highly orientated pyrolytic graphite surface as a function of potential, to reveal highly ordered lateral nanostructures with unprecedented molecular resolution. This detail allows identification of choline, chloride, and urea in the Stern layer on graphite, and in some cases their orientations. Images obtained after the potential is switched from negative to positive show the dynamics of the Stern layer response, revealing that several minutes are required to reach equilibrium. These results provide valuable insight into the nanostructure and dynamics of DESs at the solid–liquid interface, with implications for the rational design of DESs for interfacial applications.     

Interrogation of an Enzyme Library Reveals the Catalytic Plasticity of Naturally Evolved [4+2] Cyclases

Stereoselective carbon-carbon bond forming reactions are quintessential transformations in organic synthesis. One example is the Diels-Alder reaction, a [4+2] cycloaddition between a conjugated diene and a dienophile to form cyclohexenes. The development of biocatalysts for this reaction is paramount for unlocking sustainable routes to a plethora of important molecules. To obtain a comprehensive understanding of naturally evolved [4+2] cyclases, and to identify hitherto uncharacterised biocatalysts for this reaction, we constructed a library comprising forty-five enzymes with reported or predicted [4+2] cycloaddition activity. Thirty-one library members were successfully produced in recombinant form. In vitro assays employing a synthetic substrate incorporating a diene and a dienophile revealed broad-ranging cycloaddition activity amongst these polypeptides. The hypothetical protein Cyc15 was found to catalyse an intramolecular cycloaddition to generate a novel spirotetronate. The crystal structure of this enzyme, along with docking studies, establishes the basis for stereoselectivity in Cyc15, as compared to other spirotetronate cyclases.