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Thermal degradation of commercial polystyrene was investigated by XRD and FT-IR methods. The samples were heated 30 minutes at temperatures 140ºC, 200ºC, 250ºC, 300ºC and 350ºC and then brought back to room temperature. XRD investigation denotes structural modification for samples heated above 200ºC. This modification is confirmed by FT-IR measurements. Some vibration bands are affected by thermal degradation at temperatures higher than 200ºC. Both FT-IR and XRD methods reveal modification of microscopic structure of the polystyrene submitted to thermal degradation.

The current study was carried out to monitor the dynamics of phenolic compounds and vitamin C variations in Hippophae rhamnoides L. (sea buckthorn) under the influence of different color filters, as follows: yellow (590 nm), blue (450 nm), and violet (400 nm). The fruits were harvested at maturity from different parts of the canopy (i.e., base, middle, and top), immediately stored at −18 °C, and afterward lyophilized to reduce the loss of compounds for preparing the chemical assays that were carried out. HPLC-DAD-ESI+ was used to determine the phenolic compounds and vitamin C content of the fruits. EPR (electron paramagnetic resonance) measurements were also carried out to confirm the antioxidant character of the berries. This is the first study to examine the effect of different color filters on the accumulation of phenolic compounds and vitamin C content in the fruits of sea buckthorn. Among the three color filters used, the violet filter proved to be the most beneficial for the accumulation of total phenolic compounds (3.326 mg/g) and vitamin C (1.550 mg/g) in the berries. To reach high contents of phenolic compounds and vitamin C, the best setup included using very-high-energy emission LEDs as close as possible to blue and violet (400–450 nm). Therefore, the different light color intensities and temperatures on each level of a canopy play key roles in enhancing the phenolic compound content, antioxidant activity, and vitamin C content of sea buckthorn fruits. This knowledge will help provide insights into the accumulation of secondary metabolites and improve future production strategies in sea buckthorn.

In recent years, essential oils (EOs) have received increased attention from the research community, and the EOs of cinnamon, patchouli, and geranium have become highly recognized for their antibacterial, antifungal, antiviral, and antioxidant effects. Due to these properties, they have become valuable and promising candidates for addressing the worldwide threat of antimicrobial resistance and other diseases. Simultaneously, studies have revealed promising new results regarding the effects of physical fields (magnetic and electric) and LASER (MEL) exposure on seed germination, plant growth, biomass accumulation, and the yield and composition of EOs. In this frame, the present study aims to investigate the influence of MEL treatments on cinnamon, patchouli, and geranium EOs, by specifically examining their composition, antimicrobial properties, and antioxidant activities. Results showed that the magnetic influence has improved the potency of patchouli EO against L. monocytogenes, S. enteritidis, and P. aeruginosa, while the antimicrobial activity of cinnamon EO against L. monocytogenes was enhanced by the electric and laser treatments. All exposures have increased the antifungal effect of geranium EO against C. albicans. The antioxidant activity was not modified by any of the treatments. These findings could potentially pave the way for a deeper understanding of the efficiency, the mechanisms of action, and the utilization of EOs, offering new insights for further exploration and application.

Some physical properties of poly (acrylic acid) gels with embedded gold nanoparticles, (PAA-GNP), as prepared and after neutralization with triethanolamine, (TEA), were investigated by UV-VIS and fluorescence methods. The UV-VIS spectra of the PAA-GNP gels contain the characteristics absorption peaks of both PAA and GNP pure components, with modified intensities and positions. Excitation at 250 nm of pure PAA and pure GNP are followed by characteristic fluorescence transitions. The peaks of pure components appear in the fluorescence spectrum of the PAA-GNP gels with some modifications compared with the pure state. Some modifications of the UV-VIS and florescence spectra were observed after neutralization with TEA. The particularities of these spectra indicate some changes of the conformation of the polymeric matrices after the introduction of GNP and after neutralization.

Poly(acrylic) gels, (PAA), with polymeric concentrations 0.5, 1 and 1.5%, in aqueous state and neutralized with triethanolamine, (TEA), were investigated by UV-VIS and fluorescence methods. Such gels are suitable to obtain biocompatible matrices for some medical drugs. The aqueous gel with 1% PAA concentration shows an important absorption at 214 nm. At 1.5% PAA concentration the absorption increases and the peak shifts slowly to 212 nm. The absorption increases after neutralization and the maximum of absorbance shifts to 200 nm. Excitation of aqueous gels at 250, 270 and 290 nm is followed by two important fluorescence transition centered at 320 and 405 nm. The position of the fluorescence peaks is influenced by the polymeric concentration and by the neutralization. The UV-VIS and fluorescence investigations indicate some conformational changes determined by the neutralization.

Essential oils and aromatic plants have been cherished since ancient times for their versatile applications in food preservation, cosmetics, perfumery, and healing, as well as for spiritual and religious purposes. Their rich history is well-documented, showcasing extensive activities and a wide range of therapeutic benefits. Today, essential oils have captured renewed interest from both the public and the scientific community, heralding them as promising agents for the prevention and treatment of numerous medical conditions, thereby enhancing our overall quality of life and wellbeing. This review delves into the fascinating world of essential oils, covering their historical significance, extraction methods and chemical composition.

Essential oils, derived from aromatic plants, possess a wide array of bioactivities that have drawn significant interest in both traditional medicine and modern scientific research. This review explores the diverse bioactivities and underlying modes of action of essential oils. Essential oils exhibit a broad spectrum of biological activities, including antimicrobial, anti-inflammatory, antioxidant, antispasmodic, and analgesic effects. These bioactivities are attributed to the complex chemical composition of essential oils, primarily consisting of terpenes, phenolics, and aldehydes, which interact synergistically. The mode of action of essential oils is multifaceted, involving various biochemical and molecular mechanisms.

The starch in native forms or chemically modified is found as the main component of biodegradable packaging materials. Regarding this the water can produce a fast degradation, of the order of days, of such materials. Four types of packaging materials, one witness and three with different starch, glycerol and water ratios were subjected to natural degradation after absorption of distilled water. The degradation process was monitored by various NMR relaxometry methods based on the measurement of CPMG (Carr-Purcell-Meiboom-Gill) decays with a T1 filter to exclude the signal from free water. The analysis of NMR signal decays was performed using a Laplace inversion algorithm and the dynamic components were identified from the T2 transverse relaxation times distributions. We found that the best package with 68/17/15 ratios between starch/glycerol/water is extremely degraded after just one day forming a colloid substance. After that in time we observe a quasi-solid precipitation at the bottom of NMR tube. The reduction of dynamics is observed also in the T2–distributions measured for 5 days. The most resistant package (78/19.5/2.5) was that with a large content of starch but which was also reaching the swallow limit in five days and start to be decomposed.

This section is dedicated to a Romanian contemporary poet, belonging to the Echinox literary movement, Viorel Mureșan.