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Urtica dioica L. is one of the most widely utilized medicinal plants commonly applied in the form of tea, juice, and dietary supplements. This study aimed to assess the effect of the U. dioica ethanol–water extract (UdE) and polyphenolic fraction isolated from the extract (UdF) on normal human colon epithelial cells and to evaluate their protective activity against induced oxidative stress. The cytotoxic potential against human colorectal adenocarcinoma (HT29) and the anti-inflammatory effects were also investigated. UPLC-MS-DAD analysis revealed that both extracts were abundant in caffeic acid derivatives, specifically chlorogenic and caffeoylmalic acids, and therefore, they showed significant protective and ROS scavenging effects in normal human colon epithelial cells. Moreover, they had no negative impact on cell viability and morphology in normal cells and the extracts, particularly UdF, moderately suppressed adenocarcinoma cells. Furthermore, UdF significantly decreased IL-1β levels in HT29 cells. Our research indicates that U. dioica may provide significant health advantages because of its antioxidant and anti-inflammatory effects.

Ocimum basilicum is a valuable plant widely consumed worldwide and considered a rich source of polyphenols. This study examined the impact of the polyphenolic fraction isolated from basil (ObF) on human normal colon epithelial cells and human colorectal adenocarcinoma cells, evaluating its anti-inflammatory and protective activity against oxidative stress. The phytochemical characterization of the fraction was performed using ultra-performance liquid chromatography (UPLC) with a photodiode detector (DAD) and mass spectrometry (MS). UPLC-DAD-MS revealed that ObF predominantly contains caffeic acid derivatives, with rosmarinic acid and chicoric acid being the most abundant. The fraction demonstrated high antioxidant potential, as shown by DPPH assays, along with significant reducing power (FRAP). Furthermore, it prevented the depletion of antioxidant enzymes, including superoxide dismutase and catalase, and decreased malonylodialdehyde (MDA) in induced oxidative stress condition. Additionally, it exhibited a significant protective effect against H2O2-induced cytotoxicity in human normal colon epithelial cells. Although it had no impact on the viability of adenocarcinoma cells, it significantly reduced IL-1β levels in the neoplastic microenvironment. Our study demonstrated that basil polyphenols provide significant health benefits due to their antioxidant and protective activities.

Isoflavones, belonging to polyphenolic compounds, show structural similarity to natural estrogens, and in this context, they have been extensively studied. Some of them are also applied as cosmetic additives; however, little is known regarding their effects on skin cells. In this investigation, common isoflavones, including genistein, daidzein, glycitein, formononetin, and biochanin A, as well as coumestrol, were evaluated for antioxidant activity and their impact on human skin fibroblasts and keratinocytes. Antioxidant effects were assessed using DPPH, ABTS, and FRAP tests, and the ability to scavenge reactive oxygen species (ROS) was tested in cells with H2O2-provoked oxidative stress. The impact on the activity of antioxidant enzymes (SOD, CAT, GSH) and lipid peroxidation (MDA) was also explored. As shown by Alamar Blue and neutral red uptake assays, the compounds were not toxic within the tested concentration range, and formononetin and coumestrol even demonstrated a stimulatory effect on cells. Coumestrol and biochanin A demonstrated significant antioxidative potential, leading to a significant decrease in ROS in the cells stimulated by H2O2. Furthermore, they influenced enzyme activity, preventing depletion during induced oxidative stress, and also reduced MDA levels, demonstrating protection against lipid peroxidation. In turn, genistein, daidzein, and glycitein exhibited low antioxidant capacity.

This paper presents a voltage control system for multiphase squirrel-cage induction generators operating at a high variability of speed and variable load. Field-oriented vector control was used with a change in the sequence of the stator phase currents what changes the number of poles of the magnetic field produced by nine-phase stator winding. At low speeds, the current sequence is changed so that the number of poles increases allowing for the desired voltage to be obtained with greater efficiency. The task of the automatic control system was to control the DC voltage to a desired value at the output of the multiphase PWM converter. This is an alternative control method to the scalar control of voltage and frequency presented in a previous work. The control method and parameters of the automatic control system result from the mathematical model of the multiphase induction machine. The results of the laboratory tests were compared with the effects of the operation of the same nine-phase scalar controlled generator.

Background and Objectives: Allergic contact dermatitis (ACD) is a serious health and socio-economic problem. Accurate and reliable assessment of exposure to ACD factors in the work environment would increase quality of life and work of employees. The aim of this study was to assess the level of exposure of workers of a multidisciplinary hospital to the factors causing ACD. Material and Methods: The proprietary OSDES-16 questionnaire was used. The effectiveness of the OSDES-16 was confirmed statistically. The study included 230 employees of the medical center in Polanica Zdrój, divided into groups. Results: The differences in the overall assessment of exposure between the individual groups in the OSDES-16 scale were statistically insignificant (p > 0.05). There was no significant correlation between the current workplace and the level of exposure to ACD (p > 0.05). The level of exposure to ACD in the group of employees with work experience in the current position for more than 10 years was significantly higher than those working less than 6 years (p < 0.05). Conclusions: Nurses, midwives and paramedics are the occupational group most exposed to the development of contact allergy related to exposure to factors present in the work environment. The seniority of more than 10 years in the current position was linked with a higher level of occupational exposure.

The subject of this publication is a method of controlling the DC voltage of a PWM rectifier supplied by a multiphase cage induction generator with the number of stator phases greater than three operating in a wide range of driving speeds. Voltage regulation is performed by changing the frequency and amplitude of the stator voltages with simultaneous switching of the phase sequence of these voltages. The step change of the voltage sequence is made in the designated ranges of the generator speed, which enables the stabilization of the output voltage in a wide range from the minimum speed of about 25% of the rated speed. Such sequence switching changes the number of pole pairs produced by the winding for each supply sequence. The difference compared to multi-speed induction machines is that, in the presented solution, there is only one winding, not a few, which enables good use of the machine’s magnetic core in the same dimensions as for the three-phase machine of a similar power. Steady-state characteristics and dynamic operation were obtained using laboratory measurements of a standalone nine-phase induction generator. The automatic control system maintained the output voltage at the set level, regardless of the generator load and driving power.

This paper presents some considerations regarding the application of the stator zero-sequence current component (ZSC) in the fault detection of cage induction machines, including the effects of magnetic core saturation. Faults such as rotor cage asymmetry and static, dynamic, and mixed eccentricity were considered. The research started by developing a harmonic motor model, which allowed us to obtain a voltage equation for the zero-sequence current component. The equation allowed us to extract formulas of typical frequencies for particular fault types. Next, in order to verify the effectiveness of ZSC in induction motor fault diagnosis, finite element calculations and laboratory tests were carried out for the previously mentioned faults for delta and wye connections with neutral wire stator winding configurations.