The effect of copper ions on interaction of UV radiation with methacrylic matrix – EPR study

The role of metal ions introduced to polymer matrix in the photochemical degradation of material is not fully understood. In this paper, we considered the effect of copper ions on the photochemical changes in Methafilcon A after UV-irradiation. The presence of methacrylic acid in the structure of Methafilcon A increases the loading capacity of these ions. In result, there is observed the production much more radicals after UV-irradiation than in pure matrix, without copper ions. When the time of UV-exposure increases, the EPR signal of trapped Cu(II) ions in the material decreases. This proves the transformation of Cu(II) to a diamagnetic state of stable Cu(I)-intermediates or copper oxides. Simultaneously, in the first 5-min of UV-irradiation there is observed a rapid increase in intensity of the radical signal, which disappears when the exposure time is extended. This mechanism of radical generating is quite different than for Methafilcon A matrix without copper ions.     

Phenol‐Based Antioxidants and the In Vitro Methods Used for Their Assessment

Abstract: In recent years, much interest has been observed in the field of phenol‐based antioxidants. As a result of this, many analytical methods have been developed for the purpose of the quantification of phenolic and polyphenolic antioxidant capacities in biological materials. Many of these methods have been altered for application toward the in vitro assessment of antioxidant activities in animal and human model systems as well as in vivo. Due to the varied applicability and usage, methods for the assessment of phenol antioxidant capacities have become so widespread that they are often misused. It is the intent of this work to review the chemistry behind the antioxidant activity of phenolics as well as summarize the many methods applicable for the measurement of in vitro phenolic antioxidant capacity.     

Enzymatic modification of protein preparation obtained from water-washed mechanically recovered poultry meat

Studies were conducted on a protein preparation obtained from washed mechanically recovered poultry meat (MRPM). The effect of addition of 3 g/kg microbial transglutaminase (MTG) to poultry meat protein was evaluated in terms of texture changes by dynamic mechanical analysis (DMA) and nuclear magnetic resonance (NMR) to determine water content in the preparation and its effect on protein. Samples with the addition of MTG were pre-incubated at 5–6 °C for 1.5, 3, 4.5, 6, 7.5, 9 and 24 h. The largest changes for both texture parameters and rheological properties were observed in the interval of approx. 4–7 h incubation. The protein preparation with the enzyme added had significantly higher values of the moduli of elasticity (G₁) and losses (G₂) in comparison to the control system. Samples with the addition of MTG also showed a higher water-binding capacity. From the NMR studies it was found that the greatest amount of water was bound by protein in the period of approx. 2.5–5 h incubation. After that time an increase was found in the amount of free water in the sample, which suggests that it was displaced from the system by stronger protein–protein bonds.     

Shape optimization in oppositely directed coupled diffusion within composite structures

Some textile dressings contain the microcapsulated therapeutic substance. The diffusion of the activating agent (the exudate) from the wound through the material initiates the chemical reaction within microcapsules and releases the therapeutic agent. The semi-permeable membrane within the dressing reduces the diffusion of therapeutic agent to surrounding, whereas the exudate diffuses normally. The oppositely directed coupled diffusion is analyzed within 2D cross-section of dressing. State variables are both activating agent concentration and therapeutic substance concentration. State equations, boundary and initial conditions are determined. The sensitivity of an arbitrary functional is analyzed by means of direct and adjoint approaches and implemented into the problem of shape optimization. The objective functionals and the optimality conditions are formulated. Numerical example of 2D shape optimization is presented.     

Auto‐thermal combustion of lean gaseous fuels utilizing a recuperative annular double‐layer catalytic converter

The results of the investigations on the auto‐thermal combustion of lean gaseous fuels in a recuperative annular double‐layer catalytic converter were reported in the current contribution. Several modifications were proposed to improve the stationary and transient behaviour of the converters. The miniaturized recuperative converter exhibited reduced resistances to the mass and heat transfer and attractive bifurcation changes of a very low combustible content, that is, the histeresis for T_in and C_in and isola for mf_in and h_g. It was revealed that the utilization of an adiabatic recuperative converter led to an autothermal operation for T_in = 300 K and C_in = 177 ppmv of propane. The inlet fuel mass flow rate range to apply was wider than earlier reported in the literature, that is, 0.63–2.94 × 10^?6 kg s^?1 for C_in = 200 ppmv. Transient experiments showed that recuperative converter was able to transfer short‐time inlet disturbances of parameters due to the energy accumulation and temporal reversed recuperation counteracting to extinction or to destructive overheating of the catalysts. Stability analysis was performed showing location of folds, stable and unstable branches of solutions for the different parameters of the recuperative converter. A two‐dimensional process model was developed.     

Monocarbonyl Analogs of Curcumin Based on the Pseudopelletierine Scaffold: Synthesis and Anti-Inflammatory Activity

Curcumin (CUR) is a natural compound that exhibits anti-inflammatory, anti-bacterial, and other biological properties. However, its application as an effective drug is problematic due to its poor oral bioavailability, solubility in water, and poor absorption from the gastrointestinal tract. The aim of this work is to synthesize monocarbonyl analogs of CUR based on the 9-methyl-9-azabicyclo[3.2.1]nonan-3-one (pseudopelletierine, granatanone) scaffold to improve its bioavailability. Granatane is a homologue of tropane, whose structure is present in numerous naturally occurring alkaloids, e.g., l-cocaine and l-scopolamine. In this study, ten new pseudopelletierine-derived monocarbonyl analogs of CUR were successfully synthesized and characterized by spectral methods and X-ray crystallography. Additionally, in vitro test of the cytotoxicity and anti-inflammatory properties of the synthesized compounds were performed.