Editorial
Grammatical and Terminological Remarks: Molen (Bulg.), Not Molaren (Bulg.)
Резюме. A rigorous definition of the mole as a unit for the amount of substance is given. The use of the adjective molar is explained. In Bulgarian molar is often translated as molaren – to the noun mol an English suffix –ar is added and then the Bulgarian suffix –en is added as well. The correct translation of molar into Bulgarian leads to the term molen. The use of molen instead of molaren is recommended.
Keywords: chemical terms, mole, molar, molen (Bulg.), molaren (Bulg.)
B.V. Toshev
Влезте в системата, за да прочетете пълната статияNews
News in Brief (January – June 2009)
E. Avramova
Влезте в системата, за да прочетете пълната статияEducation: Theory & Practice
Environmental Education as a Citizenship Education
Резюме. The intensifying contradictions between the modern society and the Nature determine the need of environmental education as a part of the citizenship education. Both are moral imperatives and the young people must be specially educated in this direction in order to feel their own responsibility to preserve the Nature for themselves and for the future generations as well. The optimal conditions and tools for such a combination are listed and commented.
Keywords: environmental education, sustainable development, citizenship education
P. Galcheva, K. Vachkov
Влезте в системата, за да прочетете пълната статияCurriculum Matters
The Periodic Table of Chemical Elements and the IUPAC Nomenclature of Inorganic Chemistry, 2005
Резюме. The nomenclature of IUPAC 2005 connected with the periodic table, the symbols and names of chemical elements, the indication of charges and oxidation numbers as well as the IUPAC approved names for elements is commented and some proper examples are given.
Keywords: IUPAC nomenclature, periodic table, symbols and names of chemical elements, oxidation numbers, ionic charges, collective names for like elements
I. Dukov
Влезте в системата, за да прочетете пълната статияProblems
First National Competition in Key Scientific Competences
Резюме. The First National Competition in Key Scientific Competences was held in Lovech, Bulgaria on March, 14th -15th, 2009. The competition is designed for five to nine grade students. All Bulgarian regions were represented by a total of 60 students who are interested in science. The new science competition is different from the existing science olympiads and competitions in respect of format, content, and student age. The best individual contestants may take part in the European Union Science Olympiad. In this paper the concepts, goals, the regulations and the results of the new competition are presented as well as one of the versions of the tasks.
Keywords: science competition, key competences, science tasks
S. Manev, A. Tafrova-Grigorova, S. Tomova, K. Yotovska, M. Gaydarova, K. Tutulkov
Влезте в системата, за да прочетете пълната статияFrom the Research Laboratories
Enzyme Modified Electrochemical Biosensor for the Study of Anticancer Action of Mitomycin C
Резюме. NADPH, cytochrome-c enzyme modified Glassy Carbon Fiber Electrode (GCFE) was fabricated for the study of DNA-Mitomycin C interaction using DPV (Differential Pulse Voltammetric) technique. The study has also been performing using anticancer drug, Mitomycin C (MC) modified, ds(double strand)-DNA modified electrochemical biosensors and at bare GCFE (Glassy Carbon Fiber Electrode), using DPV (Differential Pulse Voltammetric) technique. Mitomycin C was activated electrochemically and also using NADPH, cytochrome-c reductase enzyme. This enzymatic activation of Mitomycin C is parallel to its in-vivo metabolic activation in the cell to bind and cross link DNA. The enzyme modified GCFE was also fabricated for the study of DNA-Mitomycin C interaction. The work was supplemented by HPLC study on the adducts formed in the electrolysed solution, which revealed reductive activation of Mitomycin C to form quinone methide which covalently links itself with ds-DNA to produce adduct at the N-2 position of guanine in the minor groove. Thus, indicating the DNA cross linking and allowing Mitomycin C to work as an anticancer drug. A suitable mechanism model for the ds-DNA-Mitomycin interaction has been proposed.
Keywords: Mitomycin-C; Glassy Carbon Fiber Electrode; Electrochemical Biosensor; Enzyme Electrode; Mitomycin-C-DNA Interactions
S. Tiwari, K.S. Pitre
Влезте в системата, за да прочетете пълната статияNew Information Media
Methods and Tools of the Teaching Chemical Experiment: A University Subject and Its Instructional Design
Резюме. The aim of this paper is to describe the process of instructional design of a University subject titled ‘Methods and Tools of the Teaching Chemical Experiment. The students in Chemistry Education attend such lectures at the Department of Chemistry of the University of Sofia. Suggested instructional design process model includes: determining instructional needs, analyzing the learning task, analyzing the learning context, and analyzing the learners. On the basis of analysis’ findings organizational, delivery and management strategies have been chosen. The training is designed as a kind of e-learning, including computer-aided training (CAT). It is the use of educational materials developed, and presented on CD-ROM with the included text, images and video films; prelab activities; the use of synchronous and asynchronous learning (online chats, and e-mail) to interact with the instructor, and other learners; and to obtain support during the learning process.
Keywords: instructional design, e-learning, prelab activities, chemical experiment
T. Monova
Влезте в системата, за да прочетете пълната статияArchives
Chemistry Programme for the High Pedagogical Schools (1896)
B.V. Toshev
Влезте в системата, за да прочетете пълната статияChemistry & History of Chemistry: An Online Supplement
CHEMISTRY & HISTORY OF CHEMISTRY
Online
Влезте в системата, за да прочетете пълната статияChemistry & History of Chemistry: An Online Supplement
Towards Water-Borne Organic Synthesis: An Education in Chemistry Research
Резюме. Though undeniably indispensable, organic synthesis has been unfortunately burdened with its toxicity facet. The use of an organic medium in this synthesis has made its toxic aspect acute and more fearful. Mostly, the public image vis-à-vis to chemistry has been awesome. Fortunately, this image is now being whitened as water is being thought as an organic medium surrogate, and comparative results are quite unexpected and even surprising. In this paper, a glance at some water-borne and on-water organic reactions is delineated, aiming at sweeping off and eradicating the general belief from minds: “organic reactions work only or better in organic media”. Being acquainted with this new synthetic medium-related approach, one may dauntlessly and confidently present his chemistry to the public without any reservation.
Keywords: dispersions, aqueous media, organic reactions, water
S. Moulay
Влезте в системата, за да прочетете пълната статияChemistry & History of Chemistry: An Online Supplement
Simultaneous Determination of Cobalt and Iron Using First-Derivative Spectrophotometric and H-Point Standard Addition Methods in Micellar Media
Резюме. First-derivative spectrophotometric method based on zero-crossing over isodifferential technique and H-point standard addition method (HPSAM) are developed for simultaneous determination of cobalt (II) and iron (III) ions in micellar media. The 4-(2-pyridylazo) resorcinol (PAR) is used as chromogenic reagent for complexes formation of cobalt (II) and iron (III) ions. The measurements were carried out using cetyltrimethylammonium bromide as a surfactant, in buffered solution at pH 6 and temperature of 25 oC. The linearity obtained in the range of 0.10-2.50 µg ml-1 of Co2+ and 0.50-6.00 µg ml-1 of Fe3+ in the presence of each other by using first-derivative spectrophotometric method. The results of applying H-point standard addition method show that Fe(III) and Co(II) ions can be determined simultaneously with concentration ratio of 30:1 and 1:8 of iron to cobalt. The proposed procedures have been applied successfully for the simultaneous determination of cobalt and iron in synthetic binary mixtures and real samples.
Keywords: Derivative spectrophotometry, H-point standard addition method, Cobalt, Iron, 4-(2-Pyridylazo) resorcinol, Cetyltrimethylammonium bromide.
H.R. Pouretedal, P. Sononi, M.H. Keshavarz, A. Semnani
Влезте в системата, за да прочетете пълната статияChemistry & History of Chemistry: An Online Supplement
Using of Baby Powder Talc as a Thin Layer Chromatography Adsorbent: Teaching Chemical Experiment
Резюме. The aim of this paper is to check whether the thin layers prepared by powder containing talk and two different solvents are suitable for thin layer chromatography (TLC) and convenient to prepare slurries. The separability of the components of a commercial ink has been tested successfully.
Keywords: analytical chemistry, separation science, chromatography, TLC.
S. Ergul
Влезте в системата, за да прочетете пълната статияChemistry & History of Chemistry: An Online Supplement
School and Schooling in the Kingdom of Bulgaria: Photoarchives – Part 1
Резюме. At the Research Laboratory on Chemistry Education and History and Philosophy of Chemistry, University of Sofia, a collection of photos and other documents illustrating the school and schooling in the Kingdom of Bulgaria (1878-1946) has been established. These photos have a historical value. Some of these photos together with other two documents are shown here. The publication of such materials will continue in future.
Keywords: Kingdom of Bulgaria, educational system, school life, school-leaving certificate
B.V. Toshev
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