Multivalent Ligands with Tailor-Made Anion Binding Motif as Stabilizers of Protein–Protein Interactions

Modulation of protein–protein interactions (PPIs) is essential for understanding and tuning biologically relevant processes. Although inhibitors for PPIs are widely used, the field still lacks the targeted design of stabilizers. Here, we report unnatural stabilizers based on the combination of multivalency effects and the artificial building block guanidiniocarbonylpyrrol (GCP), an arginine mimetic. Unlike other GCP-based ligands that modulate PPIs in different protein targets, only a tetrameric design shows potent activity as stabilizer of the 14-3-3ζ/C-Raf and 14-3-3ζ/Tau complexes in the low-micromolar range. This evidences the role of multivalency for achieving higher specificity in the modulation of PPIs.     

Assisted electrochemical conversion of nitrogen heterocompounds using active hydrogen passing through a Pd membrane. A non conventional diesel and VGO hydrotreating option

The conversion of pyridine (PY), quinoline (QUI) and meso-tetraphenylporphyrin (TPP) using active hydrogen passing through a Pd membrane under mild conditions (25 °C and ambient pressure) by applying −1.92 mA cm⁻² is reported. Moreover, some results regarding VGO and diesel hydrotreating, under similar conditions, are shown. Relative kinetic conversion constants (k′), calculated for each tested molecules, support the following reactivity order: PY (k′ = 87 × 10⁻⁴ min⁻¹) > QUI (k′ = 5 × 10⁻⁴ min⁻¹) > TPP (k′ = 1 × 10⁻⁴ min⁻¹). Based on the reduction and increasing factors found for aromatic and saturated fractions respectively, it can be established that diesel is easier to transform than VGO. Nevertheless, hydrodenitrogenation seems to be more notable for VGO than for diesel.     

Analysis of free glycerol in biodiesel using an electrochemical assay based on a two-enzyme platinum microelectrode system

An electroenzymatic method based on two coupled enzymatic activities (glycerokinase and glycerol-3-phosphate oxidase) was developed using a platinum microelectrode for the determination of free glycerol in biodiesel samples. The electroenzymatic method proposed showed a good linear correlation coefficient (R = 0.9894), with a linear response in the concentration range of 8.2 × 10⁻⁵ to 5.7 × 10⁻⁴% (w/w) and a limit of detection of 6.0 × 10⁻⁵% (w/w). The results obtained for the free glycerol content of select biodiesel samples were compared with their gas chromatography (GC) analyses. The relative errors for glycerol determination using this enzymatic-amperometric method were in the range of −8.0 to 3.0%. The proposed method was shown to be promising for the analysis of glycerol in biodiesel samples and a simple and inexpensive method in comparison to gas chromatography.     

Transition metals increase hydrothermal stability of yttria-tetragonal zirconia polycrystals (3Y-TZP)

In this paper, the influence of transition metals on phase stability of zirconia in 3?mol% Y₂O₃ doped tetragonal zirconia polycrystals (3Y-TZP) in hydrothermal environments was reported. 3Y-TZP with and without stainless-steel or CoCr metal stains on the sample surface were subjected to different isothermal treatments in water vapor, and their respective monoclinic fractions were quantified by confocal Raman spectroscopy. The outputs of these spectroscopic experiments revealed transition metals conspicuously could stabilize the tetragonal zirconia polymorph in the monolithic zirconia, possibly due to the occurrence of off-stoichiometric chemistry in the presence of metal stains.     

Umkehrosmose und Chlordioxid: Einflüsse auf die Prozessperformance und bedarfsgerechte Dosage

According to the literature, there are both positive and negative effects of chlorine dioxide dosage during reverse osmosis processes with polyamide membranes. The reasons for these divergent results remain unclear. Within the scope of this study, the influence of chlorine dioxide dosage on process performance has been investigated under conditions of practical relevance. Based on this knowledge, recommendations for the reasonable application of chlorine dioxide were developed.     

Coalho Cheese Made with Protease from Thermomucor indicae‐seudaticae N31: Technological Potential of the New Coagulant for the Production of High‐Cooked Cheese

The aim of this study was to explore the use of a new coagulant from Thermomucor indicae‐seudaticae N31 for the manufacture of a high‐cooked starter‐free cheese variety, by evaluating its physicochemical and functional characteristics in comparison to cheeses made with a traditional commercial coagulant. Coalho cheese was successfully produced with the new protease as it exhibited comparable characteristics to the one produced using the commercial enzyme: pH behavior during manufacture; cheese composition; protein and fat recovery; and cheese yield. In addition, during storage, melting was low and not affected by storage time; the increase of TCA 12% soluble nitrogen (% of total nitrogen) was lower than half of that of pH 4.6 soluble nitrogen (% of total nitrogen); concentration of β‐CN significantly decreased, whereas α_s1‐CN concentration was not affected by storage time.     

Effect of Cheese pH and Temperature on Serum Phase Characteristics of Cream Cheese During Storage

Three 13.6‐kg blocks of cultured cream cheese manufactured on different days were obtained from a commercial source within 2 wk of manufacture. Blocks were sectioned into samples that were randomly assigned to 3 treatments. A model system was used to change cheese pH. One group of samples was exposed to volatile ammonia to increase the pH to about 5.3. A 2nd group was exposed to volatile acetic acid to decrease the pH to about 4.5. A 3rd group served as a control (pH about 4.8). Samples from each pH treatment were vacuum‐packaged and randomly assigned to 1 of 2 storage temperatures: 4 °C and 20 °C. Samples were randomly chosen for analysis after 4, 8, 12, 16, 20, 24, and 28 d of storage and centrifuged at 12500 ±g for 75 min at 25 °C to obtain expressible serum (ES). The ES was analyzed for viscosity at 25 °C. Effects of pH treatment, storage time, and storage temperature were evaluated by analysis of variance (ANOVA) according to a split split‐plot design. The amount of ES increased significantly during storage and was affected by storage temperature and cheese pH. Significantly more ES was obtained at higher temperature and higher pH. Viscosity of ES decreased significantly during storage and was affected by storage temperature and cheese pH. Viscosity decreased more rapidly at higher temperature and higher pH. The data suggest that higher temperature and higher pH resulted in accelerated loss of stabilizer function during storage, possibly due to microbiological degradation of the stabilizer.