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Achillea clypeolata Sibth. & Sm. essential oil composition and QSRR model for predicting retention indices
No full textThe aim of this study was the prediction model of retention indices of compounds from the aboveground parts of Achillea clypeolata Sibth. & Sm. essential oil, obtained by hydrodistillation and analysed by GC-MS. The quantitative structure-retention relationship analysis was applied in order to anticipate the retention time of the obtained compounds. The selection of the seven molecular descriptors was done by a genetic algorithm. The chosen descriptors were uncorrelated and were used to construct an artificial neural network. A total of 40 experimentally obtained retention indices was used to build this prediction model. The coefficient of determination for the training, testing and validation cycles were: 0.950, 0.825 and 1.000, respectively, indicating that this model could be used for prediction of retention indices for A. clypeolata, essential oil compounds
Antioxidant Capacity and Quality of Human Milk and Infant Formula Determined by Direct Current Polarography
No full textAntioxidants present in infant food contribute to its nutritive value and provide protection from oxidative damage. Here, a direct current polarographic method, based on a decrease of anodic current from the hydroxoperhydroxo-mercury(II) complex (HPMC) formed at a mercury dropping electrode at its potential of dissolution, was used to determine the total antioxidant capacity (TAC) of infant formulas, human milk collected from mothers of full-term and preterm infants, human milk supplemented with fortifier, and cow milk. TAC of milk samples and infant formula correlated with protein content measured by the Bradford method (Pearson correlation coefficient 0.605, p LT 0.001), while TAC of human milk correlated with content of free thiol groups measured by the Ellman method (0.779, p LT 0.001). The results obtained showed that, in contrast to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, HPMC enables specific insight into the quality of infant milk food which reflects the amounts of free thiol groups and protein content. The significant contribution of milk proteins and the most prevalent amino acids, particularly cysteine, arginine, and phenylalanine, to TAC was shown. Thus, the HPMC method might be useful in monitoring the quality of infant formulas and human milk for preterm infants before and after supplementation with fortifier
Computer-Controlled Voltage/Current Source and Response Monitoring System for Electrochemical Investigations
No full textIn this paper, a computer-controlled voltage and current source, together with aresponse monitoring system for electrochemical investigations, is presented. The measuring system consisted of two major parts: the measuring hardware (HW) and the proprietary software. The hardware included the data acquisition USB card NI USB 6211 from National Instruments Company as well as all needed circuits (the analogue front end, the signal conditioning circuits, and power supplies). The software is based on the LabVIEW platform from National Instruments, and it is designed to control the signal generation and measurements, to cancel the noise in the signals, and to calibrate the device. The supported electrochemical methods are potential, potentiostatic and galvanostatic measurements, as well as the cyclic voltammetry and impedance measurments. The system was thoroughly tested, and it was determined that the system characteristics fulfil the requirements for most of the electrochemical and bioelectrochemical measurements, supercapacitor characteristics investigations, and much more. The overall system is modular; the HW and SW can easily be upgraded to support different methods and purposes and, therefore, the performance of the system
Assessment of Efficiency of Rare Earth Elements Recovery from Lignite Coal Combustion Ash via Five-Stage Extraction
No full textRare earth elements (REE) are frequently referred to as ingredients for enhancements in modem industry, as they are extensively applied in many industrial branches due to their accented electro-magnetic and optical properties. REE have end-utilizations as catalysts, magnets, and as dopants for ceramic materials. Rare earth minerals are scarce therefore the unconventional REE-containing resources such as waste materials and industrial byproducts are continuously being investigated. Coal combustion products comprise REE concentrations varying between 200 ppm and 1500 ppm. This quantity can be isolated though the extraction procedure. In this study, the five stages extraction was conducted on the coal combustion ash from the selected landfill site. The extractions of 32 elements (As, Ga, Ce, Be, Ge, Nd, Cr, Zr, Eu, Cu, Nb, Gd, Co, Mo, Dy, Li, Ag, W, Mn, Cd, Au, Ni, In, Hg, Pb, Sn, Ti, V, Sb, Th, Zn, and La) were conveyed. Chemical analyses were conducted via XRF, ICP-OES, ICP-MS, and MS techniques. The complexity of the obtained data was examined by Principal component analysis and Cluster analysis in order to derive interconnections between quantity of elements and landfill characteristics, as well as mutual relationships among the elements of interest, and to assess the accomplishment of REE recovery from the coal ash
Distribution of polyphenolic and sugar compounds in different buckwheat plant parts
No full textThe aim of this study was to provide information on the phenolic and sugar profiles of different parts of the buckwheat plant, which can define that buckwheat is a functional food, with a high nutritional value and very useful for human health. Therefore, the extracts of buckwheat leaf, stem, and flower, as well as buckwheat grain were analysed for the content of polyphenol and antioxidant tests. The identification of a notable number of phenolic compounds and quantification of sugars in different parts of buckwheat indicates that buckwheat is a highly valuable plant. A total of 60 phenolic compounds were identified (18 cinnamic acid derivatives, 14 flavonols, 13 flavan-3-ols (including proanthocyanidins), 10 hydroxybenzoic acid derivatives, and 5 flavones) using ultra-high-performance liquid chromatography (UHPLC), coupled with a hybrid mass spectrometer which combines the Linear Trap Quadrupole (LTQ) and OrbiTrap mass analyzer. The highest number of phenolic compounds was found in the analysed buckwheat flower sample, and then in the leaf, followed by the grain and the stem. In addition, the sugar profile of buckwheat leaf, stem, flower and grain, as well as the buckwheat pollen and the nectar was analysed. Hence, 16 sugars and 5 sugar alcohols were detected by the high-performance anion exchange chromatography (HPAEC) with a pulsed amperometric detector (PAD). Sucrose was found in a significant amount with the highest content in buckwheat leaf. Trisaccharides had similar accumulation in the sample extracts, while disaccharides dominated in buckwheat leaf, followed by nectar and pollen. The sugar alcohols showed the highest content in buckwheat grain, where erythritol was predominant. The obtained results show that buckwheat is very rich in phenolic compounds and sugars. In addition to grain, the other parts of the buckwheat plant can be used as a very good source of different classes of phenolic compounds. This study provides useful information on the distribution of phytochemicals in different parts of the buckwheat plant, which contribute to the maintaining of the status of buckwheat as a functional food
Raspberry seeds extract selectively inhibits the growth of human lung cancer cells in vitro
No full textThis study was focused on in vitro cytotoxicity screening of the raspberry seeds methanol extract towards a number of cancer cell lines of human origin. The tested extract at the preferred concentrations (IC50 LT 30 mu g/mL) inhibited only the growth of the lung cancer A-549 cells (IC50 = 14.07 +/- 0.96 mu g/mL). At the same time, it was practically inactive (IC50 >300 mu g/mL) and non-mutagenic towards normal MRC-5 lung cells. Finally, the extract potently scavenged both OH center dot (IC50 = 20.11 +/- 1.77 mu g/mL) and O2-center dot (IC50 = 47.23 +/- 3.82 mu g/mL), the free radicals of proved relevance for cancer pathophysiology. Though seeds were enriched with phenolic compounds (TPC = 5.21 +/- 0.07 mg GAE/g), anthocyanins were present in traces only (TAC = 0.07 +/- 0.003 mg cyn-3-glu/g), while flavonoids were not detected at all. This is the first report on anti-lung cancer potential of the seeds of any soft fruit
Contribution of bacterial cells as nucleation centers in microbiologically induced CaCO3 precipitation-A mathematical modeling approach
No full textThe microbiologically induced calcite precipitation (MICP) has been extensively studied for geotechnical engineering through simultaneous action of natural phenomena and engineering processes. The focus of bacterial contribution to the MICP has been directed to calcium carbonate productivity, while the additional bacterial role as a crystal nucleation center was not explained especially from a mathematical prediction modeling point of view. Therefore, this study provides explanations and a mathematical modeling approach of bacterial influence on the MICP induced by newly-isolated ureolytic Bacillus strains and Sporosarcina pasteurii DSM 33. Using the obtained results of low-cost, rapid, and simple assays, artificial neural network modeling was applied for cell surface predispositions, pH changes as well as calcium-involved function in biofilm formation during the MICP, for the first time. Based on the obtained contribution of the alkalophilic/alkaloresistant bacteria, calcite precipitation can be significantly directed by the presence, of ureolytic bacterial cells as nucleation centers during CaCO3 precipitation as well as their morphology, surface characteristics, potential to form a biofilm, and/or generate pH changes
Influence of chia seeds (Salvia hispanica L.) and extra virgin olive oil addition on nutritional properties of salty crackers
No full textThis research was aimed to establish the optimum formulation of crackers based on buckwheat and rye flour, chia seed and extra virgin olive oil and subsequently examine the nutritional value of final products. The addition of chia seeds significantly affected the content of alpha-linolenic fatty acid, influencing the nutritional value of crackers, which led to the remarkable reduction in the omega-6/omega-3 ratio in both rye (2.5:1) and buckwheat crackers (2.4:1). Most of the amino acids (except serine, alanine, cystine) were not significantly (p LT 0.05) affected by the share of chia seeds, as well as the type of flour used. Due to high dietary fiber and protein content, the investigated cracker may have a claim "source of fiber" and "source of protein". Sensory evaluation of crackers showed that all examined samples of crackers exhibited excellent quality, implying that the presence of chia did not diminish, but rather improved some sensory attributes, such as texture
Development and Evaluation of Superabsorbent Hydrogels Based on Natural Polymers
No full textSuperabsorbent hydrogels (SAHs) are three dimensional networks formed by polymers that can absorb aqueous solution of over 100% of their initial weight. This work aimed to develop and characterize SAHs of Chitosan/Xanthan gum (CG), Chitosan/Alginate (CA) and controlled Chitosan (C), Xanthan gum (G), and Alginate (A) produced using "onion-like" methodology. The swelling performance, the morphological structure, the crystallinity, and the Fourier transformed infrared spectroscopy characteristics of SAH were used for the characterization of polyelectrolytes complex. Swelling analysis showed that chitosan has a strong influence on the maintenance of hydrogels structure after swelling, mainly in the acid environment (pH = 2). The chitosan hydrogel presented around 3000% of acidic fluid absorption after 24 h. The chitosan:xanthan gum (1:1 and 2:1 named as C1G1 and C2G1, respectively) hydrogels were the best combination regarding swelling performance in an acid environment, reaching 1665% and 2024%, respectively, as well at pH 7.0, presenting 1005% (C1G1) and 667% (C2G1). Scanning electron microscopy analysis showed samples with pores, and with different shapes. The X-ray diffraction showed the presence of a characteristic peak at 2 theta = 20 degrees in all developed composition because of the crystalline nature of chitosan. This work shows the possibility of developing eco-friendly biopolymer-based SAHs at a low cost with a good swelling capacity and stability
Prediction model based on artificial neural network for pyrophyllite mechano-chemical activation as an integral step in production of cement binders
No full textThe optimal outputs of pyrophyllite mechano-chemical activation in an ultra-centrifugal mill performing under different technological conditions were determined by analytical modeling and verified via Artificial Neural Network in order to be employed in the production of cement-based binders. Cluster Analysis and Principal Component Analysis were utilized in assessment of the effect of activation process parameters on the activated pyrophyllite quality. Artificial Neural Network which performed with high prediction accuracy, i.e. 0.914 during the training period, was sufficient for precise prediction of activated pyrophyllite quality in a wide range of processing parameters. The probability of utilization of observed activation products was estimated through interrelation of technological parameters (mesh size sieve, activation period, specific energy consumption) and acquired characteristics of pyrophyllite (grain diameter, specific surface area). The optimal products singled out from each activation sequence were used as mineral additives in the mix-designs of four cement binders (cement replacement portion was 30%). Influence of activated pyrophyllite additions on the cement chemistry, mineral phase compositions and microstructures of the cement binders were monitored by instrumental techniques (DTA/TGA, XRD, SEM). Activated pyrophyllite showed characteristics of pozzolana as it slightly accelerated early stages of hydration, decreased cement hydration energy and increased the quantity of cement mineral alite at later hydration stages. Micron-sized crystalline foila characteristic for mechanically activated pyrophyllite formed micro-reinforcement within cement binder microstructure