rss_2.0Chemistry FeedSciendo RSS Feed for Chemistry Feed and adaptation mechanisms of to antifungal agents<abstract> <title style='display:none'>Abstract</title> <p>Filamentous fungi are crucial for recycling of organic material in nature. In natural habitats, they cope with many stress factors and therefore their adaptation ability to various conditions is very high. <italic>Trichoderma</italic> sp., fungi used in agriculture as biocontrol agent, are exposed to a variety of toxic molecules including pesticides and fungicides. They have to fight with toxic molecules using stress adaptation mechanisms known as the stress response. Adaptation of fungi to stress, especially to chemical stress, is not well studied in environmental fungal strains. Moreover, the adaptation process presents a risk of resistance mechanism induction to antifungal agents. Such resistant strains could be spread in the environment. This work aims to contribute to the knowledge of the adaptation process spread throughout the fungal kingdom. Transcriptional response of ABC transporters, the main detoxification efflux pumps of subfamily B and G in presence of antifungal agents, is shown. On the other hand, as azoles are the most commonly used antifungal structures in clinical practice and agriculture, changes in important fungal ergosterol biosynthesis genes as a result of their exposure to various azoles structure are highlighted.</p> </abstract>ARTICLE2022-09-15T00:00:00.000+00:00Thermodynamic characterization of acid cryolite systems<abstract> <title style='display:none'>Abstract</title> <p>Measuring of the electromotive force in molten system is used to characterize thermodynamic properties of the system at equilibrium. Values of the electromotive force are very important for the determination of activity and standard electrode potential. Investigation of the electromotive force of Al + TiB<sub>2</sub> and Al-Al cell was the main aim of this work leading to the characterization of acid cryolite systems. The measurements were realized using a molten aluminum electrode and the electromotive force of an electrochemical cell was investigated in electrolytes at various molar ratios (NaF/AlF<sub>3</sub>) at equilibrium. Thermodynamic properties were measured in acid cryolite melts at three different temperatures: 800 °C, 900 °C, and 1000 °C, for all experiments.</p> </abstract>ARTICLE2022-09-15T00:00:00.000+00:00The role of deep eutectic solvents in the production of cellulose nanomaterials from biomass<abstract> <title style='display:none'>Abstract</title> <p>In recent years, the demand for environment-friendly products has been on an increasing trend among researchers and industry for sustainable development. Deep eutectic solvents are green solvents which, due to their properties (biodegradability, recyclability, low cost, availability, easy preparation, low toxicity, chemical and thermal stability), can be used in various fields such as polymer chemistry, which includes nanocellulose isolation and polysaccharides processing. Several studies have illustrated the effectiveness of using deep eutectic solvents instead of the conventional reaction system to produce and disperse nanomaterials. This work summarizes the use of deep eutectic solvents in the isolation of cellulosic nanomaterials from different types of biomass. Deep eutectic solvents demonstrate high effectiveness in swelling lignocellulosic biomass and producing cellulose nanomaterials. Overall, deep eutectics solvents represent an innovative and effective pretreatment process for the fractionation of raw cellulose-containing fibres to promote subsequent isolation of nanomaterials made from cellulose.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00DFT studies of camptothecins cytotoxicity III: camptothecin, irinotecan and SN-38<abstract> <title style='display:none'>Abstract</title> <p>Geometries of camptothecin, irinotecan, SN-38, and of their hypothetical Cu(II) complexes were optimized at the B3LYP/6-311G* level of theory. Their electron structure, evaluated in terms of Mulliken population analysis and Quantum Theory of Atoms-in-Molecule, was subsequently related to <italic>in vitro</italic> cytotoxicity. Electron density transfer from the relevant active sites to Cu decreases in the sequence irinotecan &gt; SN-38 &gt; camptothecin. The absolute values of their metal-ligand interaction energies exhibit the same trend. Discrepancy with the least relative <italic>in vitro</italic> cytotoxicity of irinotecan can be explained by differences in its pharmacokinetics.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00Simultaneous detection of purine metabolites by membrane modified electrochemical sensors<abstract> <title style='display:none'>Abstract</title> <p>Purine metabolites are important for metabolic and cellular processes. Deregulation of purinergic signaling leads to pathological accumulation of purine degradation products in extracellular fluids and indicates various diseases. In clinical diagnosis at early stages of related diseases, accurate detection of Uric acid and Xanthine is of high importance. Electrochemical methods are fast, simple, sensitive, more convenient, and cost-effective compared to other analytical methods used in purine metabolites signaling. Electrochemical sensors are able to detect more compounds simultaneously. Modification of a glassy carbon electrode sensor with external protective membranes was used in this study to avoid unwanted signal interferences from analyte matrices. Polyvinyl alcohol, Chitosan, and Nafion membranes were selected for sensor modification to compare the electro-neutral, positive and negative charged setting of the Xanthine and Uric acid detection. All three membrane modified sensors showed adequate stability in the phosphate buffer solution after 5 min of incubation and are thus suitable for simultaneous detection of purine metabolites. The best results in anodic peak current response values were observed using the Nafion membrane modified glassy carbon electrode sensor. The approach reported here can be useful for the detection of purine metabolites from various matrices at early stages of clinical diagnosis.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00How Can Hybrid Materials Enable a Circular Economy?<abstract> <title style='display:none'>Abstract</title> <p>Climate change, critical material shortages and environmental degradation pose an existential threat to the entire world. Immediate action is needed to transform the global economy towards a more circular economy with less intensive use of fossil energy and limited resources and more use of recyclable materials. Recyclable materials and manufacturing techniques will play a critical role in this transformation. Substantial advancements will be needed to achieve a more intelligent materials design to enhance both functionality and enhanced sustainability. The development of hybrid materials combining functionality at macro and nano scales based on organic and inorganic compounds, that are entirely recyclable could be used for tremendous applications. In this mini-review, we provide the reader with recent innovations on hybrid materials for application in water, energy and raw materials sectors. The topic is very modern and after its deep study we propose a creation an international research centre, that would combine the development of hybrid materials with green manufacturing. We have highlighted a framework that would comprise critical themes of the initial research needed. Such a centre would promote sustainable production of materials through intelligent hybridisation and eco-efficient, digital manufacturing and enable a circular economy in the long term. Such activities are strongly supported by current environmental and economical initiatives, like the Green Deal, REPower EU and digital EU initiatives.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00Investigation regarding the potential application of grape pomace extracts on plant growth and development<abstract> <title style='display:none'>Abstract</title> <p>The grape pomace hydroalcoholic extracts obtained by two different extraction methods were tested for biostimulatory potential activity for <italic>Origanum vulgare</italic> L. cultures. The total polyphenols contents of extracts were evaluated by Folin-Ciocalteu method. Characteristics such as: pH, salinity, conductivity and total dissolved solids were determined. FTIR and UV spectra of extracts were also recorded. The effect of grape pomace extracts on growth and development of oregano plant were studied by carrying out <italic>in vitro</italic> propagation of oregano on Murashige and Skoog basal medium supplemented with different concentrations of grape pomace extracts. Biometric measurements, growth rate and biomass accumulation have been narrowly monitored for all samples and compared to the control sample. The results have shown that the morphogenetic response depends both on the proportion in which basal medium was supplemented and on the extraction method used. A stimulation of growth and development at a low concentration of grape pomace extracts has been noted. The best results were observed in the samples with 1 and 5 % of grape pomace extract obtained by classical extraction.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00Crystal violet removal from aqueous solutions using dry bean pods husks powder – optimization and desorption studies<abstract> <title style='display:none'>Abstract</title> <p>In this study the Taguchi method was used to establish the optimal conditions for the adsorption of crystal violet dye on an adsorbent obtained from dry bean pods husk. Six factors, at three level, were considered in establishing the L27 Taguchi orthogonal array. The ANOVA analysis was performed to calculate the each factor percentage contribution on the dye removal efficiency. A desorption study was carried out to evaluate the regeneration possibility of the used adsorbent. The removal efficiency ranged from 5.91 to 94.48 % depending on the controllable factors combination set by Taguchi design. The results showed that the factor with the highest percentage contribution on the dye removal efficiency was the ionic strength (48.85 %). The correlation between the predicted values of the dye removal efficiency with those obtained experimentally indicate a good accuracy of Taguchi approach.</p> </abstract>ARTICLE2022-08-23T00:00:00.000+00:00Comparison of Bomaplex Blue CR-L Removal by Adsorption Using Raw and Activated Pumpkin Seed Shells<abstract> <title style='display:none'>Abstract</title> <p>In this study, removal of colour from wastewaters prepared synthetically using Bomaplex Blue CR-L was investigated using raw and activated pumpkin seed shells by adsorption in a batch system. The effects of stirring speed, adsorbent concentration, dye concentration, temperature and pH on colour removal were investigated, and adsorption capacities of raw and activated pumpkin seed shells were determined. In addition, adsorption kinetics, isotherm coefficients, activation energies and thermodynamic parameters were calculated. The optimal adsorption conditions were determined as pH = 2, stirring speed of 200 rpm, adsorbent concentration of 10 g L<sup>−1</sup> and 30 °C. Under the optimal conditions, the maximum removal efficiency of Bomaplex Blue CR-L using raw pumpkin seed shells was 73.01 %. This value rose to 79.71 % after activation processing was applied. Experimental adsorption data show that the adsorption is more suited to the Langmuir adsorption model and works in accordance with the pseudo-first-order kinetics model. As a result of thermodynamic research, <italic>ΔH°</italic> and <italic>ΔS°</italic> were 31.515 kJ mol<sup>−1</sup> and 109.952 kJ mol<sup>−1</sup> K<sup>−1</sup> for the raw adsorbent, respectively. For the activated adsorbent, Δ<italic>H</italic>° and Δ<italic>S</italic>° were 43.118 kJ mol<sup>−1</sup> and 152.237 kJ mol<sup>−1</sup> K<sup>−1</sup>, respectively. The activation energy of adsorption was calculated as 10.918 kJ mol<sup>−1</sup> for the raw adsorbent and 9.882 kJ mol<sup>−1</sup> for the activated adsorbent.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Physicochemical Changes and Abundance of Freshwater Snails in Anambra River (Nigeria) During the Rainy Season<abstract> <title style='display:none'>Abstract</title> <p>Rapid diversification is a way of responding to environmental change for freshwater organisms. This work examined the physicochemical changes and abundance of freshwater snails in Anambra River (Nigeria) during the rainy season. Field studies were conducted fortnightly from June to August 2019 at three stations of the river namely: Otuocha (station I), Otunsugbe (station II), and Ukwubili (station III) about 8.35 kilometers apart from each other. A scoop net of 2 cm mesh size and handpicking was used to sample freshwater snails randomly and water samples were taken to the laboratory for physicochemical analysis. A total of 896 freshwater snails belonging to 6 species (<italic>Afropomus balanoidea</italic>, <italic>Pomacea maculata</italic>, <italic>Lymnea stagnalis</italic>, <italic>Lanistes ovum</italic>, <italic>Pila wernei</italic>, and <italic>Saulea vitrea</italic>) were collected. <italic>Pomacea maculata</italic> was the most dominant species with a relative abundance of 45.87 %, while <italic>Saulea vitrea</italic> was the least dominant species with a relative abundance of 2.34 %. There was a significant negative correlation between dissolved oxygen and <italic>Pomacea maculate</italic> (<italic>r</italic> = –0.877, <italic>p</italic> = 0.002) and a positive correlation between dissolved oxygen and <italic>Stagnalis lymnea</italic> (<italic>r</italic> = 0.840, <italic>p</italic> = 0.005). The diversity of species was highest at Otuocha (1.171) followed by Ukwubili (1.133) and Otunsugbe (0.856) with average mean temperatures of (23.1 ±0.1) °C, (27.30 ±0.00) °C, and (26.80 ±0.03) °C respectively. The distribution of freshwater snails was influenced by the physicochemical variability of Anambra River during the rainy season. Therefore, further studies for a longer time and different seasons to examine the impact of physicochemical changes on the snail distribution are encouraged.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Heavy Metal Atmospheric Deposition Study in Azerbaijan Based on Moss Technique and Neutron Activation Analysis<abstract> <title style='display:none'>Abstract</title> <p>The results of this investigation show that Azerbaijan industries and agricultural sector provide considerable anthropogenic impact on the environment of Caucasus. The use of moss biomonitoring technique and neutron activation analysis (NAA) is a first attempt to study heavy metal atmospheric deposition in Azerbaijan, a country different relief and climate. The study was undertaken in the summer of 2015 of atmospheric deposition of man-made heavy metal pollutants in the area of mining and processing plant in Gadabay and Dashkasan mininig district. At the same time samples were collected from the Goygol State Reserve in the Lesser Caucasus not far from the city of Ganja. A total 85 moss samples (predominantly <italic>Pleurozium schreberi</italic>) collected in both environmentally contrast area. Elemental determination was carried out by epithermal neutron activation analysis (ENAA) at the reactor IBR-2 of Joint Institute for Nuclear Research (FLNP JINR). For the first time 44 elemental concentrations were determined (Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, Ta, W, Au, Th, U). Multivariate statistical analysis of the analytical results obtained will make it possible to identify the main sources of pollution and to assess the role of long-range transport of pollutants.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Impact of Air Pollution on Maize and Wheat Production<abstract> <title style='display:none'>Abstract</title> <p>To determine the effects of air pollution on crop yields, weather, air pollution, and maize and winter wheat yield data from 331 cities in China from 2014 to 2016 were collected and analysed. Furthermore, support vector regression and the crop growth model were applied to extrapolate the air pollution data of Beijing and Hetian and verify the relationship between air pollution and yield. Precisely, heavy air pollution usually occurred in North China, but less than moderate air pollution levels affected crop yields statistically insignificantly. Moreover, both the winter wheat and maize yields increased in moderate air pollution periods but decreased in heavy air pollution periods in 2014, 2015 and 2016. Importantly, a threshold value was necessary for the heavy air pollution periods to trigger a yield decrease. The threshold values of maize in 2015 and 2016 were 7 days and 5 days, respectively, while that of winter wheat was 10 days in both 2015 and 2016. Once the heavy air pollution periods exceeded the threshold value, both the winter wheat and maize yields decreased linearly with the periods. PM2.5 was the main air pollutant in Beijing in 2014, while PM2.5 and PM10 were the main air pollutants in Hetian in both 2015 and 2016. Regardless of whether the main air pollutant was PM2.5 or PM10, the simulated potential winter wheat yields by the crop growth model with moderate air pollution for the whole growth period were all higher than the yields under observed and heavy air pollution conditions.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00An Assessment of Environmental Risk of Bt-Maize on Rove Beetle Communities<abstract> <title style='display:none'>Abstract</title> <p>An environmental risk assessment related to the genetically modified crops still needs to be studied. In the non-target organisms, rove beetles seem to be well-chosen arthropods for this purpose. Rove beetle abundance and species diversity were studied in the first large-scale Bt-maize experiment in the south part of Poland for over two years to determine the impact of Bt-maize in comparison to conventional varieties. A genetically engineered Bt-maize variety (DKC 3421 Yield Gard<sup>®</sup>, event MON 810) and its near-isogenic DKC 3420 were cultivated at two locations. Additionally, two non-Bt varieties sprayed with a lambda-cyhalothrin insecticide were also included for comparative analysis. The results show no significant effects on rove beetle abundance and diversity patterns of the Bt-maize and the nearby isolines. In one locality the mean number of individuals and Simpson dominance was even higher in Bt-maize compared to one reference variety. The Canonical Correspondence Analysis showed rather variety-dependent effects of the rove beetle community. To conclude, considering the abundance and diversity of studied insects, there is no environmental risk arising from Bt-maize cultivation.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Research on the Effects of Rare Earth Combined Contamination on Soil Microbial Diversity and Enzyme Activity<abstract> <title style='display:none'>Abstract</title> <p>Soil microorganisms and soil enzyme activities are important indexes to evaluate soil status. The soil pollution status was evaluated by measuring the physical and chemical properties and heavy metal content of rare earth combined contaminated soil around the Maoniuping old mining area and tailings ponds in different seasons, and measuring the number and diversity of microorganisms and the soil enzyme activities of the arable soil microecology. This research shows that the physical and chemical properties of farmland soil in old mining areas and tailings ponds in different seasons are significantly different, the concentration of rare earth combined contamination in old mines is greater than that in the tailings area, and the changes in the concentration of rare earth combined contamination cause significant changes in soil microecology. Rare earth combined contamination inhibits fungal and bacterial vital activities and promotes the growth of actinomycetes; reduces the sensitivity of sucrase to heavy metal contamination, promotes the activity of phosphatase, and the effect on urease is that of “promotion at low concentration and inhibition at high concentration”; and reduces the community’s ability to use carbon sources and, as a result, the community species are rare and distributed unevenly and the community structure is simple. These results indicate that rare earth combined contamination is potentially harmful to soil microorganisms, which can provide a theoretical basis for the ecological restoration of farmland soil in mining areas.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Fractionation and Bioavailability of Phosphorus and Its Relation to Chlorophyll- at the Coastal Area of Semarang City<abstract> <title style='display:none'>Abstract</title> <p>We investigate the distribution of various fractions phosphorus (P) in sediments at the coastal area of Semarang City. Samples were collected from thirteen locations at the Banjir Kanal Barat, port and Banjir Kanal Timur. Sedimentary parameters such as sand, silt, clay, and organic carbon were analysed in order to find out their relation with various P fractions. The sediment types are predominantly sandy and silty with low clay content. Among all fractions (loosely bound/Ads-P), bound calcium/Ca-P), iron bound/Fe-P), and organic fraction/OP), Ca-P fractions constitute the largest portion (71.2 %) followed by iron-bound (17.0 %), organic fraction (10.4 %) and loosely bound (1.4 %). The bioavailable P fractions range from 20.2 % to 42.0 % of the total P (TP) content with average 28.8 %. Relatively high Ads-P content is observed in offshore locations with comparatively high mud percentage as compared with the near-shore locations. The order of abundance of the main forms of P in the Semarang coastal surface sediments is as follows: Ca-P &gt; Fe-P &gt; OP &gt; Ads-P. The concentration of this fraction causes the abundance of chlorophyll-<italic>a</italic> from 9.09 to 21.09 mg/m<sup>3</sup>.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Thiabendazole Fungicide Adsorption Onto Four Agricultural Soils Collected from the Loukkos Area of Northwestern Morocco<abstract> <title style='display:none'>Abstract</title> <p>A serious environmental problem can arise from the presence of pesticides in soils and waters. Hence, in this study we have carried out the adsorption of the Thiabendazole fungicide onto four soils collected from several areas in Morocco as Larache, Laouamra, Ksar kebir and Tlata drissana. Physicochemical properties, elemental analysis, X-ray diffraction (XRD) were investigated to characterise the four selected soils. The experimental equilibrium data were analysed using Langmuir, Freundlich models. The equilibrium data were best described by a Langmuir model for all adsorbents. The maximum estimated adsorption capacity was 0.747 mg∙g<sup>−1</sup>, 0.751 mg∙g<sup>−1</sup>, 0.473 mg∙g<sup>−1</sup> and 1.083 mg∙g<sup>−1</sup>, for Larache, Laouamra, Ksar kebir and Tlata drissana soils, respectively.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00Biological Monitoring Using Lichens as a Source of Information About Contamination of Mountain with Heavy Metals<abstract> <title style='display:none'>Abstract</title> <p>The aim of this study was passive biomonitoring of the mountains of southern Poland. Lichens <italic>Hypogymnia physodes</italic> were used for the study. Concentrations of the heavy metals Ni, Cu, Zn, Cd and Pb were determined in these lichens. The concentrations were measured by atomic absorption spectrometry (AAS). The analysis of the concentrations of the determined heavy metals in the lichen thallus allowed to determine the places with the highest and the lowest contamination with a given heavy metal in the study area. It was shown that the area of Great Czantoria and Big Soszow is the most contaminated with heavy metals among the investigated areas. The study shows that the transport of analytes with the wind from distant emission sources, low-level emission (coal burning), and traffic have the greatest influence on the level of atmospheric aerosol pollution in the study area.</p> </abstract>ARTICLE2022-08-17T00:00:00.000+00:00No : Why Theistic Evolution Fails review of the toxicity of triazole fungicides approved to be used in European Union to the soil and aqueous environment<abstract> <title style='display:none'>Abstract</title> <p>This review provides the summarized current knowledge on the degradation and effects on the non-target organisms from soil and aquatic environment of the triazole fungicides approved to be used in most of the European Union also taking into account stereospecific differences. Synthetized data reveal that triazole fungicides are usually persistent in aqueous environment and soil, and manifest moderately acute and chronic toxicity against the organisms living in these environments. Furthermore, the enantiomers of triazole fungicides proved to have distinct distribution and effects on these environments. These data are important for assuring a sustainable agriculture by production and use of single-stereoisomer and/or encouraging a management of agricultural crops with minimum effects on environment.</p> </abstract>ARTICLE2022-07-28T00:00:00.000+00:00Temperature dependence studies and microscopic protonation constants of L-alanine and β-alanine in acetonitrile – water mixtures<abstract> <title style='display:none'>Abstract</title> <p>L-alanine and β-alanine are important biological molecules and have zwitterion structure. In this study, L- alanine and β-alanine’s microscopic protonation constants and thermodynamic parameters (enthalpy, entropy, and free energy changes) for the proton–ligand systems of L-alanine methyl ester, β-alanine and β-alanine methyl ester have been determined at 5; 20; 35 °C, in ACN-water (25% ACN and 50% ACN (v/v)) mixtures at constant ionic strength of 0.1000 mol L<sup>–1</sup> NaClO<sub>4</sub> by potentiometric method. The results shown that, L-alanine and β-alanine’s microscopic protonation constants generally tend to decrease with temperature rise and their protonation reactions in ACN-water mixtures generally favor enthalpy-driven.</p> </abstract>ARTICLE2022-07-28T00:00:00.000+00:00en-us-1