RIOFH - Repository of Institute of General and Physical Chemistry
Not a member yet
1118 research outputs found
Sort by
3.5-scFv-beta-lactamase, a new protein detector of picric acid, the highly nitrated organic explosive
No full textA new protein detector of 2,4,6-trinitrophenol (TNP, picric acid) is concisely reported herein for the first time. In brief, the gene of a specific scFv fragment, namely 3.5, was fused separately with the gene of beta-lactamase and, subsequently, expressed in the periplasmic space of Escherichia coli, affording in such a way the recombinant fusion protein 3.5-scFv-beta-lactamase. This bifunctional immunoreagent tool was further convincingly demonstrated for being capable to directly detect trinitrophenol-tris(hydroxymethyl)aminomethane (TNP-Tris), a less toxic TNP derivative of choice compared to TNP itself, with competitive sensitivity (50 +/- 2 fmol or 175 +/- 6 pg/mL)
Assessment of Metal Intake by Selected Food Supplements Based on Beehive Products
No full textThe aim of this study was to determine the quantity of particular toxic metals (Pb, Cd, As, Hg) and micronutrients (Cr, Fe, Co, Ni, Cu, Zn, Se) in the recommended daily dose of 51 food supplements based on beehive products. Samples taken from the Croatian market were submitted for the identification/quantification of studied metals and micronutrients. It was carried out by means of inductively coupled plasma mass spectrometry (ICP-MS). Eleven samples (21.57%) showed an increased concentration of total arsenic, three samples (5.88%) contained an increased concentration of total iron, and eight samples (15.68%) had an increased concentration of total nickel. Three samples (5.88%) contained an increased concentration of zinc, while one sample (1.96%) contained an increased concentration of selenium. Increased levels of certain toxic metals and micronutrients do not pose a danger to human health because the amount identified was less than what can cause toxic effects in humans. All other analysed metals and micronutrients fell within the defined literature values. Despite certain increases in particular parameters, all samples met the established toxicity criteria. This study evidenced their safety if consumed in the recommended daily dose
Melissopalynology analysis, determination of physicochemical parameters, sugars and phenolics in Maltese honey collected in different seasons
No full textMalta, a country renowned for its honey, has not been extensively mentioned in studies based on honey. In addition to many parameters, the collection period affects honey quality, precisely due to the different floral composition that exists during a certain season. Therefore, the significance of this study refers to the provision of data on honey from Malta collected during the autumn, spring, and summer seasons. Melissopalynological analysis, determination of physicochemical parameters, and the use of analytical chromatographic methods enabled detailed analysis of this honey. Principal component analysis (PCA) provided the differentiation of Maltese honey depending on the harvest season. Lotus pollen, followed by Eucalyptus, predominated in all honey samples. Characteristic compounds for summer honey were pinocembrin, galangin, kaempferol, chrysin, p-hydroxybenzoic acid, vanillic acid and maltotriose, while quercetin 3-O-galactoside, ferulic acid, ellagic acid, protocatechuic acid, luteolin 7-O-glucoside and melibiose were specific for autumn honey. A higher amount of p-coumaric acid, genistein, catechin, as well as the content of many sugars were found in spring samples. To the best of our knowledge, this is the first scientific work dealing with a detailed chemical analysis of Maltese honey
Soil yeasts promoting plant growth: benefits for the development of common wheat and white mustard
No full textA large number of soil microorganisms arc characterized as plant growth promoting, but there seems to be a lack of comprehensive knowledge regarding plant growth promoting soil yeasts. The aim of the experiment was to analyse the properties of three yeast species: Schwanniomyces occidentalis BK0302D, Cyberlindnera saturnus CK2404I and Candida tropicalis 2TD2912B, important for plant growth (ammonium sulphate transformation, phosphorus, potassium and zinc dissolution), and to evaluate the effect of yeast on the growth of common wheat and white mustard seedlings after seeds' inoculation. Common wheat and white mustard seeds were inoculated with the selected yeasts. The final measurements showed that the highest amount of nitrate (10.40 mu g mL(-1) NO3-) was produced by C. saturnus CK24041, while S. occidentalis BK0302D solubilized the largest amount of phosphorus (63.70 mu g mL(-1) P). All three strains are marked as potassium and zinc solubilizers with both acid and alkaline phosphatase activity. This is the first report on S. occidentalis and C. tropicalis ability to solubilize insoluble potassium and zinc, and C. saturnus ability to solubilize insoluble phosphorus, potassium and zinc. Also, C. tropicalis 2TD2912B exhibited high antagonistic activity (66% growth inhibition) toward Botrytis cinerea. In vivo trial was conducted in a low-nutrient substrate, and S. occidentalis BK0302D was found to have the most considerable influence on common wheat biomass production (34% increase). White mustard inoculation with C. saturnus CK24041 resulted in a 4-fold higher biomass production, while S. occidentalis BK0302D induced a 2-fold increase. The presented results confirmed the multi-functional plant growth promoting characteristics of the tested yeasts and their potential for broad application from conventional agriculture on low-nutrient soils to revegetation of disturbed substrates
Presence of Alternaria toxins in maize from Republic of Serbia during 2016-2017
No full textThe aim of this study was to apply modern analytical tools, liquid chromatography-tandem mass spectrometric method (LC-MS/MS), for identification and quantitation of Alternaria metabolites in maize samples. Maize samples were collected from the main maize-producing regions (Backa, Banat, and Srem) of the Republic of Serbia during two harvest seasons (2016 and 2017). The most commonly detected Alternaria toxin in maize samples from both years was tenuazonic acid. On the other hand, determined mean concentrations of quantified tenuazonic acid were significantly higher in maize samples from Banat from both maize growing seasons in comparison to its concentrations in maize samples from Backa and Srem. As a consequence of influence of microclimate conditions in investigated regions, the highest percentages of contaminated maize samples by Alternaria toxins, in both the years 2016 and 2017, were 48% and 47%, respectively from Srem, while the lowest percentages of 29% and 23%, respectively were found in Backa. Novelty impact statement The main novelty of this study is achieved through increased knowledge and creation of one of the few database from this part of Europe regarding the frequencies of occurrence of "emerging" Alternaria toxins in maize, depending on weather conditions and some of the applied agrotechnical measures during a two-year period
The effect of operating parameters of hydrodynamic cavitation - assisted alkaline catalyzed transesterification of sunflower oil with methanol on the degree of triglyceride conversion
No full textThe effect of operating parameters such as reaction mixture inlet pressure p (1) (101.3-1013.2 kPa), methanol to oil molar ratio M (1) (3-12), the concentration of catalyst C ( c ) (0.0-1.0 wt%), temperature T (25-50 degrees C) and the number of passes of the reaction mixture through the venturi type hydrodynamic cavitation reactor n (1-12) on alkali-catalyzed transesterification of sunflower oil with methanol assisted by hydrodynamic cavitation (ACTC) on the value of the degree of triglyceride conversion (DTC) was investigated. ACTC was performed by the venturi-type hydrodynamic cavitation reactor (VCR) of our construction. It was found that the values of DTC increase with the increase in p (1), M (1), C ( c,) and n, and decrease with the increase in T. Cavitation yield (CY) values were calculated. The ACTC was proved to be the simplest, fastest, and most highly energy-efficient current technology for the production of biodiesel
Transesterification of Sunflower Oil in the Presence of the Cosolvent Assisted by Hydrodynamic Cavitation
No full textCombination of chemical treatment by cosolvent with hydrodynamic cavitation is a novel technique of intensification of alkali-catalyzed transesterification of sunflower oil with methanol. The paper investigated the effect of operating parameters such as reaction mixture inlet pressure (p(1)), methanol to oil molar ratio (M-1), the concentration of catalyst (C-c), methanol to tetrahydrofuran (THF) molar ratio (M-2), temperature (T), and a number of passes through the hydrodynamic cavitation reactor (n) of transesterification of sunflower oil in the presence of the cosolvent assisted by hydrodynamic cavitation (ACTC) on the triglyceride conversion (TC). ACTC was performed by a venturi-type cavitation reactor (VCR) of a given design. The effect of the operational parameters on the TC was investigated by the method of independent variation of the value of one operating parameter. The obtained results indicated that (a) at p(1) >= 304.0 kPa TC increased from TC = 0 to TC = 98% following the rise in p(1); (b) maximum TC = 95% was achieved at M-1 = 3; (c) rise in M-1 within range 3 LT = M-1 LT = 9 led to a linear increase from TC = 95 to TC = 100%; (d) maximum TC = 95% was achieved at 1.0%wt LT = C-c >= 1.1%wt; (e) maximum TC = 99% was achieved at M-2 = 1.5; (f) TC linearly decreased from TC = 95 to TC = 88% with T rise from T = 20 to T = 55 degrees C; (g) the rise in n resulted in a linear increase of TC from TC = 94 (n = 1) to TC = 99% (n = 10); and (h) cavitation yield (CY) declines from CY = 0.528 (n = 1) to CY = 0.056 g/J (n = 10)
What is the most relevant method for water absorption determination in ceramic tiles produced by illitic-kaolinitic clays? The mystery behind the gresification diagram
No full textThis study presents the 51 mixtures of ceramic clays characterized by using XRF, XRD, granulometry, and dilatometry analyses. After firing in a 1000-1250 degrees C range, water absorption (WA) according to EN standards by boiling in water, under vacuum, and by 24h soaking is determined. The results indicated that there was a high and statistically significant correlation between the standard methods, but the testing under vacuum gave the highest saturation of the samples fired at 1200 degrees C and 1250 degrees C. It is determined that these illitic-kaolinitic clays can be used to produce floor ceramic tiles belonging to the BIIa group (water absorption between 3% and 6%). The study also aimed to reveal which method of WA determination is suitable to read the sintering interval from the gresification diagrams, which is compared to the beginning of sintering as read from dilatometry curves