RIOFH - Repository of Institute of General and Physical Chemistry
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Application of Artificial Neural Networks in Performance Prediction of Cement Mortars with Various Mineral Additives
No full textThe machine learning technique for prediction and optimization of building material performances became an essential feature in the contemporary civil engineering. The Artificial Neural Network (ANN) prognosis of mortar behavior was conducted in this study. The model appraised the design and characteristics of seventeen either building or high -temperature mortars. Seven different cement types were employed. Seventeen mineral additives of primary and secondary origin were embedded in the mortar mixtures. Cluster Analysis and Principal Component Analysis designated groups of similar mortars assigning them a specific purpose based on monitored characteristics. ANN foresaw the quality of designed mortars. The impact of implemented raw materials on the mortar quality was assessed and evaluated. ANN outputs highlighted the high suitability level of anticipation, i.e., 0.999 during the training period, which is regarded appropriate enough to correctly predict the observed outputs in a wide range of processing parameters. Due to the high predictive accuracy, ANN can replace or be used in combination with standard destructive tests thereby saving the construction industry time, resources, and capital. Good performances of altered cement mortars are positive sign for widening of economical mineral additives application in building materials and making progress towards achieved carbon neutrality by reducing its emission
Analysis of antioxidant potential of fruit and vegetable juices available in Serbian markets
No full textAntioxidants in fruit and vegetable juices have become increasingly popular because of their potential health benefits. Nowadays, juice mixes made from berries present frequent consumer choices, due to their nutritive value and high content of bioactive compounds. Commercial fruit and vegetable juices available in Serbian markets (n = 32) were analyzed for the physicochemical properties, chemical composition, and antioxidant activity. Relative antioxidant capacity index was used for the ranking of the juices according to antioxidant capacity, while antioxidant effectiveness of phenolic compounds contained in juice samples was investigated depending on phenolic antioxidant coefficients. Principal component analysis was applied to study the data structure. In addition, a multi-layer perceptron model was used for modeling an artificial neural network model (ANN) for prediction antioxidant activity (DPPH, reducing power, and ABTS) based on total phenolic, total pigments, and vitamin C content. The obtained ANN showed good prediction capabilities (the r(2) values during training cycle for output variables were 0.942). Phenolic, pigments, and vitamin C contents showed a positive correlation with the investigated antioxidant activity. The consumption of commercial berry fruit juices available in Serbian markets may deliver great health benefits through the supply of natural antioxidants
Recovery of Polyphenolic Compounds and Vitamins from the Stinging Nettle Leaves: Thermal and Behavior and Biological Activity of Obtained Extracts
No full textStinging nettle (SN) is an extraordinary plant from the Urticaceae botanical family. It is well-known and widely used in food and folk medicine to treat different disorders and diseases. This article aimed to study the chemical composition of SN leaves extracts, i.e., polyphenolic compounds and vitamins B and C, because many studies ascribed high biological potency to these compounds and their significance in the human diet. Besides the chemical profile, the thermal properties of the extracts were studied. The results confirmed presence of many polyphenolic compounds and vitamins B and C. It also showed that the chemical profile closely correlated with the applied extraction technique. The thermal analysis showed that analyzed samples were thermally stable up to about 160 degrees C. Thermal degradation of samples UAE, MAE, and MAC took place in four steps, and sample SE in three steps. Altogether, results confirmed the presence of health-beneficial compounds in stinging nettle leaves and indicated the possible application of its extract in pharmaceutical and food industries as both a medicinal and food additive
TEMPERATURE PATTERN MEASUREMENTS IN BRIGGSRAUSCHER OSCILLATORY REACTION WITH THE STATE I TO THE STATE II TRANSITION
No full textComposition and Functionality of Coriander Essential Oil
No full textCoriander is a significant plant grown mainly for its seeds due to their high essential oil content. The isolation of oil from its seeds requires the application of different extraction techniques such as hydrodistillation and supercritical fluid extraction. This chapter will be focused on up-to-date published results in this research field. The introduction will deal with coriander itself and its significance and extraction techniques used to isolate essential oil (e.g., hydrodistillation and supercritical fluid extraction). The central part of the chapter will be dedicated to the chemical composition of essential oil, optimization of the extraction process using the Box-Behnken design and response surface methodology, and the biological activity of the obtained oil and compounds found in it. Certain conclusions will be drawn from the analyzed results in the final part of the chapter
Persicaria amphibia, an old traditional remedy and wild edible herb: in vitro evaluation of cytotoxicity and antimicrobial properties [Persicaria amphibia, stari tradicionalni lek i samonikla jestiva biljka: in vitro procena citotoksičnosti i antimikrobnih svojstava]
No full textPersicaria amphibia (subfam. Polygonoideae), an aquatic macrophyte rich in dietary polyphenolics, is used as a traditional remedy and culinary herb. Nevertheless, P. amphibia from the Balkan region has been insufficiently studied and underutilized. Here, the cytotoxicity and antimicrobial properties of the previously chemically characterised ethanol extract of P. amphibia aerial parts were tested. The following methods were carried out: the MTT assay, qRT-PCR, microdilution assay, Chromobacterium violaceum screening assay (monitoring of quorum sensing, QS) and the agar plating method (antifungal activity). The study was conducted to determine the cytotoxic effects of P. amphibia against lung cancer cells (A549) and its combination with cytostatic doxorubicin (Dox). A dose-dependent decrease in cell viability (up to 82% reduction) and additive interactions of the tested agents were noted. Both alone and combined with Dox, P. amphibia reduced the expression of Nrf2 (p LT 0.05). In terms of antimicrobial effects, P. amphibia exhibited an antipathogenic effect since it disrupted QS communication, which was evident through the inhibition of violacein production of C. violaceum CV025. The antifungal screening revealed that P. amphibia induced significant growth inhibition of Aspergillus spp. (28.23%). Based on the obtained results, further examination of the potential use of P. amphibia in modern phytotherapy and diet-derived cancer chemoprevention is encouraged
Derivatives of L-Ascorbic Acid in Emulgel: Development and Comprehensive Evaluation of the Topical Delivery System
No full textThe dual controlled release of emulgels makes them efficient drug delivery systems of increasing interest. The framework of this study was to incorporate selected L-ascorbic acid derivatives into emulgels. From the formulated emulgels, the release profiles of actives were evaluated considering their different polarities and concentrations, and consequently their effectiveness on the skin via a long-term in vivo study that lasted for 30 days was determined. Skin effects were assessed by measuring the electrical capacitance of the stratum corneum (EC), trans-epidermal water loss (TEWL), melanin index (MI) and skin pH. In addition, the sensory and textural properties of emulgel formulations were compared with each other. The changes in the rate of the release of the L-ascorbic acid derivatives were monitored using the Franz diffusion cells. The obtained data were statistically significant, and indicated an increase in the degree of hydration of the skin and skin whitening potential, while no significant changes in TEWL and pH values were detected. The consistency, firmness and stickiness of the emulgels were estimated by volunteers applying the established sensory evaluation protocol. In addition, it was revealed that the difference in hydrophilic/lipophilic properties of L-ascorbic acid derivatives influenced their release profiles without changing their textural characteristics. Therefore, this study highlighted emulgels as L-ascorbic acid suitable carrier systems and one of the promising candidates as novel drug delivery systems
The study of composition-properties relationships for composite hydrogels based on poly(methacrylic acid) and high concentrations of MFI zeolite
No full textHigh concentrations of hydrophobic MFI zeolite (26.0-51.3 wt%) were successfully embedded in poly(meth-acrylic acid) (PMAA) network in simple, one-pot synthesis of PMAA-MFI composite hydrogels. The effects of zeolite concentration regarding pure PMAA xerogel, for all of the investigated properties (primary structural parameters, morphological properties, water swelling ability, thermal degradation mechanism and stability, and mechanical properties) were determined and discussed. The PMAA-MFI composite hydrogels had remarkably higher density than PMAA xerogel (1660/1420 kg m-3), higher crosslinking density (29/1.0 x 10-4), improved mechanics in the dry and swollen state (up to 4.9 times higher storage modulus) and lower swelling degree (42/ 420 g g-1), average molar mass between the network crosslinks (3.6/110 x 104 g mol-1), and distance between the macromolecular chains (64/710 nm). Despite high zeolite concentration, the composites kept porous hydrogel structure with uniformly dispersed zeolite particles. FTIR spectra disclosed the existence of functional groups of PMAA network and MFI zeolite that interacted mutually and led to increased crosslinking density. The effect of zeolite concentration on the thermal degradation mechanism was established. The composition -properties correlations were determined and described by the adequate linear or power law equations revealing the additive nature of the composites and the fractal structure of the networks. These correlations enable the achievement of desired properties by simple adjustment of the initial composition, i.e. zeolite con-centration. Therefore, this work presents the base for further development of tailor-made PMAA-MFI composite hydrogels aimed for specific application
