rss_2.0Chemistry FeedSciendo RSS Feed for Chemistry Feed and biological nitrogen fixation in soybean ( L.) as influenced by phosphorus fertilization and arbuscular mycorrhizal inoculation<abstract><title style='display:none'>Abstract</title><p>Arbuscular mycorrhizal fungi (AMF) can be used to promote the productivity of legumes on phosphorus- (P) deficient soils. The present study investigates the inoculation effects of three AMF species (<italic>Funneliformis mosseae</italic>, <italic>Rhizophagus intraradices</italic>, and <italic>Claroideoglomus etunicatum</italic>) and the control (uninoculated) on nitrogen fixation efficiency and growth performance of tropical soybean cultivar (TGx1448-2E) under varying P fertilizer rates (0, 20, and 40 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup>) in a derived savannah of Nigeria. The results showed that shoot and root dry matter, number of nodules, relative ureide abundance (RUA), nitrogen derived from atmosphere (Ndfa), total N fixed, shoot P uptake, grain, and biomass yield significantly increased with AMF inoculation, with better performance observed in plants inoculated with <italic>Rhizophagus intraradices</italic> and <italic>Funneliformis mosseae</italic> compared to <italic>Claroideoglomus etunicatum</italic>. Similarly, the soybean growth variables, P uptake, and nitrogen fixation activities increased with increasing P application rates. Conversely, AMF root colonization significantly reduced with increasing P rate. Interaction of AMF inoculation and P rates significantly influenced soybean growth and nitrogen fixation. <italic>R. intraradices</italic> inoculation with 20 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup> resulted in the highest amount of RUA, Ndfa, N fixed, and grain yield. It could be concluded from this study that <italic>R. intraradices</italic> with moderate P rate could be used to enhance nodulation, nitrogen fixation, and soybean yield in P-deficient soils.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00The analytical assessment of the weaknesses of the agriculture of Szabolcs-Szatmár-Bereg County based on empirical research results<abstract><title style='display:none'>Abstract</title><p>In our empirical research, we examined the agriculture of Szabolcs-Szatmár-Bereg County. We surveyed the situation of agriculture through farmers using certain criteria to rank the situation within the framework of a SWOT analysis. The responses received from farmers in the county were quantified and evaluated on the basis of what these farmers have considered to be true. The interdisciplinary study of agriculture is a timely and important task. It can be enforced on the basis of systemic contexts studying not only food production but also environmental issues, preservation of rural habitats, employment, and regional development.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00Seedling and adult plant resistance to in Ethiopian rice cultivars<abstract><title style='display:none'>Abstract</title><p>Two separate experiments were done for seedling and adult resistance in rice varieties against blast. Each experiment consists of 20 varieties and is evaluated under artificial inoculation with blast. The result of the study confirmed that NERICA varieties have shown low disease infection at the seedling stage whereas the varieties Chewaka and Edget have shown adult plant resistance. Severe yield reduction and highly diseased grain were obtained from Superica-1, which is highly susceptible at adult plant stage. In contrast, the maximum grain yield was obtained from the Chewaka and Edget varieties, these having a high level of adult resistance. Therefore, Chewaka and Edget are promising candidates for utilization in yield and blast resistance in rice improvement.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00PM concentration reduction due to the wet scavenging in the Ciuc Basin, Romania<abstract><title style='display:none'>Abstract</title><p>The PM<sub>10</sub> concentration reduction caused by large-scale precipitation in the Ciuc Basin was studied under no-wind conditions. The PM<sub>10</sub> concentration changing before, during, and after the rainfall was followed up from 2008 to 2019. After the rainfall episode, the PM<sub>10</sub> concentrations were lower in the cold and warm periods with 2.8 μg/m<sup>3,</sup> and 2 μg/m<sup>3</sup> respectively. The highest PM<sub>10</sub> concentration reduction was detected in the cold season, by the moderate and light rain intensity, after 6 hrs of continuous rain (35.61%, 32.46%), and the average PM<sub>10</sub> concentration reduction in the cold and warm periods was 22.3% and 16.1% respectively.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00Comparative analysis of relevant climate change, landscape and regional development strategies regarding the areas pertaining to Debrecen (Hajdú-Bihar County)<abstract><title style='display:none'>Abstract</title><p>Today, the countries of the world have to face several global challenges with regard to the plans they have developed together. The protection of the natural values of our country and their sustainable use is receiving more and more attention in today’s society. In order to achieve the above, a change of perspective in social strategy built on knowledge and professional training is inevitable. An environmental strategy paradigm shift emphasizing the protection of biodiversity, resources, and landscape cultivation is also necessary. The need for documents providing a basis for the paradigm shift is indubitable; however, more efforts are needed to induce fundamental changes by plans detailed in the documents.</p><p>The aim of this study is to review the current environmental protection initiatives in Hajdú-Bihar County and to assess the degree to which the relevant plans are harmonized and that the objectives outlined in the documents overlap.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00The influence of slope aspect on soil moisture<abstract><title style='display:none'>Abstract</title><p>In this research, we investigated the variability of soil moisture on two slopes of opposite aspect (a northern slope and a southern slope) but with the same soil type. To identify the spatial disposal of the soil type on both slopes, we georeferenced the paper-based soil map of Sfântu Gheorghe, using the QGIS platform. In order to use the correct slope aspect, we used a numerical model of the terrain (relief). The research plot was soil sampled at the depth of 10 cm on two different dates: on 7 November 2019 and on 3 March 2020, using a Buerkle soil sampler.</p><p>Gravimetric method was used to determine the soil moisture values that proved to be the most accurate for our purpose.</p><p>The soil moisture values, obtained in weight percentage, were assigned to the coordinates of the sampling points, and soil moisture maps were generated in QGIS for both slopes and for both sampling dates. These maps gave us the opportunity to evaluate the variability in time of the soil moisture distribution on the sample plots.</p><p>The water holding capacity of the soils is mostly influenced by their organic C content. So, the total organic carbon content of the soil from the sampling plots was measured using the Tyurin method.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00Genetic variation in common bean ( L.) using seed protein markers<abstract><title style='display:none'>Abstract</title><p>The genetic diversity of common bean accessions were assessed using seed storage protein markers. At regional level, accessions from the two major growing regions showed the highest level of gene diversity (H = 0.322, I = 0.485, and H = 0.312, I = 0.473), which can be exploited for the future improvement of the crop. Based on phaseolin, the major storage protein in common bean, the majority of the accessions (86%) were grouped under Mesoamerican gene pool. Seed proteins were also used to differentiate various Phaseolus species, indicating the usefulness of seed storage proteins in species identification in this genus.</p></abstract>ARTICLE2020-12-28T00:00:00.000+00:00Remediation of CO in Boudouard’s Reaction as an Example of Reversible Chemical Reaction<abstract><title style='display:none'>Abstract</title><p>One of the fundamental elements of a scientist's work is the ability to lead observations of the phenomena that surround us and based on them making conclusions. These observations are conducted within the so-called scientific experiments. Lessons learned based on the results obtained in experiments allow researchers to better understand the essence of the phenomena occurring in the world around us. Drawing conclusions is not always easy. In order to achieve this skill, we must possess a well-established knowledge in the field of the phenomenon that interests us. The most striking example of how important skills are observation and drawing proper conclusions is the phenomenon of global climate warming. The main parameter influencing temperatures registered on Earth is the concentration of greenhouse gases in the atmosphere, and especially carbon dioxide created from combustion processes. A significant role in studies of the reduction of CO<sub>2</sub> emissions plays chemists. To be sure that conducted by them experiments are optimally designed, it is necessary to ensure them with proper education already at the secondary school level. The main aim of this article was to conduct the study in order to explain chemical issues that create the greatest cognitive difficulties among students. The second aim of the article was to propose a chemical experiment to students that would allow them to find out more about the phenomena governing in the area of problematic issues. The proposed experiment is based on the concept of solubility equilibrium. Results of preliminary tests that have been carried out after applying this experiment on a small group of students, indicated their better understanding of the studied subject.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Determining Cellulolytic Activity of Microorganisms<abstract><title style='display:none'>Abstract</title><p>Decomposition of cellulose to glucose requires complex cooperation of glycoside hydrolase enzymes. As a result of glycoside β-1,4 bonds hydrolysis, shorter chains of cellulose, oligodextrin, cellobiose and glucose are created. A number of bacteria and fungi demonstrate the capacity to degrade cellulose. Their activity can be assessed with the use of qualitative and quantitative methods. Qualitative methods with the use of e.g. Congo red, are used in screening studies, however, they do not provide information about the quantity of the produced enzyme. Spectrophotometric methods are more accurate and they measure the quantities of reducing sugars with the use of appropriate substrates, e.g. carboxymethylcellulose is used to determine endoglucanases, avicel cellulose to determine exoglucanases and Whatman filter paper to determine total cellulolytic activity. Activity of microorganisms depends not only on their species or type but also, among others, on substratum composition, cultivation conditions and the appropriate selection of parameters of the carried out enzymatic reactions.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Lower-Secondary School Chemistry Textbooks’ Didactic Equipment<abstract><title style='display:none'>Abstract</title><p>Textbooks’ fundamental influence on teaching is caused not only by their subject matter, but also by their didactic elaboration. Textbooks’ individual functions are fulfilled through incorporated structural elements. Their pool is referred to as the didactic equipment of the textbook and represents qualities of the textbook through the options it gives to its users. The presented overview of lower-secondary chemistry textbooks’ didactic equipment included 7 series of currently available textbooks. Results of the analysis serve not only as a possible guide for chemistry teachers’ textbook selection, but they also provide insight into the current state to authors of textbooks and other didactic materials. Chemistry textbooks for lower-secondary schools achieve relatively high didactic equipment (75-92 %). The best equipped are the series of textbooks published after the current state curriculum introduction (by publishing houses Fraus and Nova Skola). Surprisingly, however, the most recently published textbooks by the Taktik publishing house showed the lowest didactic equipment.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Pupils’ Preconceptions About Heat, Temperature and Energy<abstract><title style='display:none'>Abstract</title><p>This article is focused on finding out pupils’ preconceptions about heat, temperature and energy. As a research tool we used a didactic test with individual types of tasks about the concepts. A total of 122 respondents aged 12 to 14 participated in the research. The research sample consisted of two groups of pupils. One group consisted of pupils attending a school assigned for talented pupils, for simplicity they are referred as talented pupils. The second group consisted of pupils who do not attend this type of school, we marked them as “general population”. The number of respondents in the sample of talented pupils was 54. The number of respondents in the sample “general population” was 68 pupils. In the research we compared ideas about concepts heat, temperature and energy of talented pupils and pupils of the “general population”. We also compared talented pupils and pupils of the “general population” in solving of conceptual and algorithmic tasks in didactic test. We found out pupils of the age from 12 to 14 have misconceptions about the concepts. We also identified the misconceptions and the most common are also mentioned in this article.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Study on Toxicity of Biometal(II) Monensinates Against Rat Zajdela Liver Tumour<abstract><title style='display:none'>Abstract</title><p>The ability of Monensic acid A (MonH∙H<sub>2</sub>O) and its neutral metal complexes [M(Mon)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]with ions of Mg<sup>2+</sup>, Ca<sup>2+</sup>, Mn<sup>2+</sup>, Co<sup>2+</sup>, Ni<sup>2+</sup> and Zn<sup>2+</sup> to decrease viability and proliferation of primary cell cultures, originating from a chemically induced transplantable liver tumour of Zajdela in rats, and bone marrow cells from the same tumour-bearers, was evaluated. Experimental data revealed that manganese(II) and nickel(II) complexes of Monensin A are relatively more selective against the tumour as compared to the healthy bone marrow cells.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Water Quality and Ichthyofauna Habitat Conditions in Lake Czolnowskie (N-W Poland)<abstract><title style='display:none'>Abstract</title><p>Increasing anthropopressure affects natural ecosystems and may express itself in regional or spot contamination of water and soil environment. The quality of ground and surface waters depends to a large extent on drainage area management, where biogenic substances (i.e. nitrogen, phosphorus and potassium) are transported with surface run-offs to the environment. The article discusses results of studies on the drainage area of Lake Czolnowskie (Zachodniopomorskie Province). Studies covered physical and chemical assessment of soil conditions and water quality; additionally, fish was caught using two independent methods - gillnets and power generator (pursuant to CEN EN 14011 2003 and PN-EN 14011 2006). Results obtained confirm regular run-off of biogenic materials from the surface of farmed drainage area to Lake Czolnowskie. During the period of studies, the reservoir was exposed to i.e. reduction of water oxygen (3.56 mg/dm<sup>3</sup>) and permanently elevated level of general phosphorus (0.15-0.27 mg/dm<sup>3</sup>) and ammonium acid (0.16-0.27 mg/dm<sup>3</sup>), which degraded the quality of life for ichthyofauna inhabiting the lake.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Human Resources and R&D at the Institute for Nanomaterials, Advanced Technologies and Innovation (TUL)<abstract><title style='display:none'>Abstract</title><p>Within the next few years, Europe’s economic paradigm will change fundamentally. Its manufacturing base will continue to shrink, and therefore future growth and social welfare will rely increasingly on knowledge-intensive industries and services, and ever more jobs will require a higher education qualification. Human resources are a core determinant of quality in higher education and research. Universities must therefore work to enhance their human potential, both qualitatively and quantitatively, by attracting, developing and keeping talent in teaching/research careers. Excellence may only emerge from a favourable professional environment based in particular on open, transparent and competitive procedures. Research and development (R&amp;D) has proven to be a crucial factor in shifting the world’s technological frontiers, while at the same time facilitating new technological and scientific innovations. This paper will focus on R&amp;D at the Institute for Nanomaterials, Advanced Technologies and Innovation at the Technical University of Liberec, Czech Republic. After a description of a literary search in the introduction, the specific real situation at this institute is mentioned, i.e. the number of submitted and solved national and international projects, statistics on research and development sources, and of course human resources at the institute. In the conclusion, the reader will be able to get a picture of how to increase the institute competitiveness in international collaboration.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Conditions for Experimental Activities at Elementary and High Schools from Chemistry Teachers’ Point of View<abstract><title style='display:none'>Abstract</title><p>School experiments represent a necessary means of subject-matter presentation in chemistry education and are important for chemical (scientific) thinking. Despite being a focus of several texts, a complex view on the experimental activity in chemistry education in Czechia is missing. The results of a questionnaire survey among 466 lower-secondary, lyceum and grammar school teachers focused on types of conducted experiments, their frequency, the place they are conducted. The most frequently used chemicals and sources of inspiration are presented in the paper. The results show that despite experiments’ significant role in education, its occurrence is rather seldom and teacher’s demonstrations prevail over students’ experiments. The list of the most often used chemicals suggests the experiments are mostly focused on inorganic chemistry. These results open further questions regarding occupational safety at schools as an important factor which could also be the reason for such a low representation of experiments in Czech chemistry education.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Hydrogen - Some Historical Highlights<abstract><title style='display:none'>Abstract</title><p>The early history of experiments in which an inflammable air was prepared is outlined. Once hydrogen had been discovered by Cavendish in 1766, the world of science and technology was given a colossal impetus. Its scientific and social consequences form the main focus of this essay. Special attention is given to explain why experiments were done, and their aims. The many difficulties which confronted scientists in the interpretation of their results are discussed. Timelines have been used in order to facilitate an understanding of the evolution of ideas. A particular emphasis is given to the story of how, through spectral analysis of the hydrogen atom, our understanding of atomic structure developed. Experiments involving hydrogen constitute important teaching material in schools. Detailed instructions are given for making hydrogen in the laboratory and for demonstrating its lightness and flammability. Suggestions are made of how to use these reactions to teach a wide variety of chemical concepts and facts.</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Basic Multivariate Statistical Methods for Environmental Monitoring Data Mining: Introductory Course for Master Students<abstract><title style='display:none'>Abstract</title><p>The present introductory course of lectures summarizes the principles and algorithms of several widely used multivariate statistical methods: cluster analysis, principal components analysis, principal components regression, N-way principal components analysis, partial least squares regression and self-organizing maps with respect to their possible application in intelligent analysis, classification, modelling and interpretation to environmental monitoring data. The target group of possible users is master program students (environmental chemistry, analytical chemistry, environmental modelling and risk assessment etc.).</p></abstract>ARTICLE2021-01-29T00:00:00.000+00:00Identification of corrosion products on iron artefact from Bratislava castle<abstract> <title style='display:none'>Abstract</title> <p>Corrosion layers of an iron artefact were characterized to study long-term exposition of iron in Slovakia. The iron artefact from Bratislava castle has been coated with a strong layer of corrosion products and masonry residues. Corrosion products were characterized by different methods including energy-dispersive X-ray spectroscopy (EDX), X-Ray diffraction (XRD), and µ-Raman Spectroscopy. Magnetite and goethite on the surface are confirmed typical corrosion products from long-term atmospheric exposure in environment with corrosivity category C-2 (low).</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00Alachlor — ecotoxicity of ozonation by-products<abstract> <title style='display:none'>Abstract</title> <p>This work focuses on the assessment of alachlor toxicity, its impact on aquatic and terrestrial ecosystems, non-target organisms, and humans, as well as with pesticide legislation in the European Union and Slovakia. In the experimental part, the pesticide alachlor was degraded by various ozone-based processes. Toxicity of the original substance and its degradation products was evaluated by ecotoxicity tests on white mustard and bulb onion. Respirometric measurements were performed to assess their effect on the microorganisms of activated sludge process. From the results it is possible to evaluate that the degradation of alachlor by ozonation at alkaline pH resulted in less toxic substances compared to the original pesticide.</p> </abstract>ARTICLE2021-09-10T00:00:00.000+00:00Influence of sea buckthorn juice addition on the growth of microbial food cultures<abstract> <title style='display:none'>Abstract</title> <p>The aim of the article was to investigate the effect of sea buckthorn juice addition on the growth of microbial cultures in growth medium and juice mixtures. Pure sea buckthorn juice was found to inhibit the growth of all 11 monitored microbial cultures. <italic>Lactobacillus plantarum</italic> CCM 7039, <italic>Lactobacillus plantarum</italic> K816, <italic>Lactobacillus brevis</italic> CCM 1815 and, to a lesser extent, the probiotic strain <italic>Lactobacillus rhamnosus GG,</italic> grew in a growth medium containing a 25 % addition of sea buckthorn juice. <italic>Lactobacillus plantarum</italic> K816 and <italic>Lactobacillus brevis</italic> CCM 1815 grew better in this mixture than in pure growth medium. Moreover, we focused on finding a suitable ratio of sea buckthorn and apple juice for <italic>Lactobacillus plantarum</italic> CCM 7039, leading to malolactic fermentation, which results in an increase in the pH value and an improvement in the sensory properties of juices. The intention was to incorporate the highest possible addition of sea buckthorn juice while maintaining the viability of <italic>Lactobacillus plantarum</italic> CCM 7039 for malolactic fermentation to occur. The best results were achieved using 40 % sea buckthorn juice. Practical application of the results points to the possibility of preparing a fermented fruit beverage and a dairy product containing sea buckthorn juice. The results of this work extend the current options of sea buckthorn juice processing increasing thus the consumption of healthy juice.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00en-us-1