Investigation of the changes in physical properties of PES/PVC fabrics after aging

The aim of this work was to investigate the physical and mechanical performance of architectural polyester (PES)–poly(vinyl chloride) (PVC) membranes exposed to different artificial aging conditions. Two commercially available architectural membranes were chosen as research objects. The durability of the PES/PVC fabrics was evaluated by the loss in mechanical performance, scanning electron microscopy, and X-ray diffraction analysis in order to understand the effect of the degradation agents on the surface of the membranes. The mechanical performance of the PES/PVC membranes was unchanged. Scanning electron microscopy images of the tested materials showed initial cracks after aging. The X-ray fluorescence analysis showed that at the time of aging, the amount of Cl and Si decreased slightly, while Ti decreased by half, and Ca by volume increased twice. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47523.     

E-beam lithography of computer generated holograms using a fully vectorial 3D beam propagation method

A fully vectorial 3D beam propagation method (BPM) has been applied to obtain a required pattern of computer generated hologram (CGH) with a variable profile of four phase levels. The computer reconstruction of the CGH image having one and two focal spots was performed by application of the fully vectorial 3D BPM method. After transferring the CGH by EBL technique an adequate phase profile was obtained. Inter-level parameter method was developed to obtain the estimated an electron beam dose required for the even topographical patterning. Using this method, an EBL exposure dose determined to achieve the required relief amplitude of 1.29 μm was 43 μC/cm². The manufactured holograms showed that the overall proposed production process, from the 3D BPM computer simulation to e-beam lithography, can be used to obtain good quality product with reasonable time and computational resources.     

Detection and analysis of triterpenic compounds in apple extracts

A new technique for the rapid detection and analysis of triterpenic compounds in apple extracts using HPLC was developed and validated. The main advantage of this technique is the short duration of the analysis – this makes this technique superior to others currently applied for the routine HPLC analysis of triterpenic compounds. The developed, optimized, and validated technique was used for the evaluation of triterpenic compounds in samples of different cultivars of apples, their peels, and flesh. In total, four triterpenic compounds were isolated and identified. Ursolic acid was the dominant compound in all the tested apple samples. The highest amounts of triterpenic compounds were detected in the peels of the ‘Lodel’ apple cultivar, and thus apples of this cultivar may be potentially useful for the isolation of individual compounds and the production of functional food and dietary supplements.     

Achillea millefolium L. s.l. herb extract: Antioxidant activity and effect on the rat heart mitochondrial functions

An extract of Achillea millefolium herb (YE) was investigated for antioxidant activity using chemical and biological assays. Qualitative and quantitative analysis of some major phenolics was carried out by HPLC. An on-line HPLC-DPPH assay showed that YE possesses significant antiradical activity which is due to the presence of active components amongst phenolic compounds. Furthermore, direct effects of YE and a mixture of its identified phenolic compounds (MPC) on isolated rat heart mitochondrial function were investigated. We found that YE in concentration-dependent manner induce a decrease in State 3 respiration rate without any changes in the integrity of inner mitochondrial membrane. Thus, pyruvate oxidation was affected only by the highest used YE concentrations; meanwhile succinate oxidation was reduced even at lower YE concentrations. MPC had no effect on mitochondrial State 3 respiration rate. Fluorimetric measurements demonstrated that YE at concentrations that had no effect on the State 3 respiration rate significantly decreased H₂O₂ production in mitochondria.     

Simulation of Adhesive–Dissipative Behavior of a Microparticle Under the Oblique Impact

The adhesive–dissipative behavior of a microparticle under the oblique impact is investigated numerically and the new discrete element method (DEM)-compatible interaction model is elaborated. The modeling approach is based on the Derjaguin–Muller–Toporov model of normal interaction for the adhesive elastic contact. Adhesion hysteresis is specified by the loss of the kinetic energy governed by the fixed amount of the adhesion work, required to separate two adhesive contacting surfaces. This effect is captured in the new interaction model by adding an additional dissipative force component to normal contact during unloading and detachment. The essential feature of this approach, differing from that of the viscous damping model, is that, according to the proposed method, the amount of the dissipated energy is not influenced by the actual initial velocity during the entire contact. The influence of adhesion on slip friction is reflected by considering the adhesive normal force components in the Coulomb's law of friction. The contribution of the adhesion-related dissipation is illustrated by a comparison of the behavior of the attractive–dissipative and attractive–non-dissipative models. The oblique impact of a microparticle on the plane surface at the intermediate impact angle is also investigated numerically. The link between adhesion and friction is supported by the numerical results.     

Measurements and analysis of the electromagnetic fields of mobile communication antennas

The owner of a mobile telephone is exposed to radiation from both the mobile telephone and base stations. They are often installed on the roofs of residential buildings. The article deals with electromagnetic fields generated by mobile communication antennas in the residential area. Measurements of electrical strength, magnetic strength and the electromagnetic field energy flux density were performed and compared to the established hygiene norms. Tests were conducted in the near and far zones of the antenna, in residential premises located directly in front of antenna, within the main radiation lobe of the antenna.     

Chemocommunication in Phyllonorycter ulmifoliella (HBN.) (Lepidoptera: Gracillariidae): Periodicity, Sex Pheromone, and Inhibitors

(Z)-10-Tetradecenyl acetate (Z10-14:OAc) from abdominal tip extracts of virgin females of the tentiform leafminer moth Phyllonorycter ulmifoliella (Lepidoptera: Gracillariidae) was identified by gas chromatography and mass spectrometry. The biological activity of the component was confirmed by field tests with synthetic compounds. As a sex pheromone component this ester is novel both in the family Gracillariidae and in the superfamily Gracillarioidea. Field trapping of P. ulmifoliella with synthetic Z10-14: OAc at dosages of 1 and 0.2 mg/dispenser led to catches of approximately 9000 and 3000 male moths, respectively. The attractivity of the Z10-14:OAc was strongly inhibited by a 10% admixture of either (Z)-9-tetradecenyl acetate (Z9-14:OAc), (E)-9-tetradecenyl acetate (E9-14:OAc), or (E)-11-tetradecenyl acetate (E11-14:OAc). Addition of 10% (E)-10-tetradecenyl acetate (E10-14:OAc) to the sex pheromone reduced attractivity, but significantly less than the inhibitors previously mentioned. The pheromone releasing (or “calling”) behavior of virgin P. ulmifoliella females was recorded under laboratory conditions. Calling activity started about half an hour before lightson and the maximum number of calling females was registered half an hour after the start of photophase. A high level of pheromone releasing activity lasted for about 2 hr and ceased about 5 hr after the start of photophase. Chemocommunication activity in the light period of day is assumed to be an adaptation which allows this phyllonoryctid to avoid inhibitors emitted as pheromones by many other species. A scheme of probable interactions by means of semiochemicals between P. ulmifoliella and other lepidopterans is presented and the appearance of Z10-14: OAc as a sex pheromone component in Lepidoptera during evolution of the order is discussed.     

A Comparative Study of Phenolic Content in Apple Fruits

The ethanol extracts of apple fruits harvested from the cultivars Aldas, Auksis, Ligol, and Lodel grown in Lithuania were analyzed by the high-performance liquid chromatography method. Chlorogenic acid was found to be a predominant component in the apple fruits of all the cultivars, except the cultivar Ligol. (–)-Epicatechin was the major compound in the ethanol extracts of apple fruits obtained from all the cultivars, while the amount of (+)–catechin was lower. The following quercetin glycosides were identified and quantified: hyperoside, isoquercitrin, avicularin, rutin, and quercitrin. Hyperoside was the major quercetin glycoside in apple fruits.