Имобилизиране на фруктозил-трансфераза върху композитни филми от полимлечна киселина, ксантан и хитозан

Author(s): Ilia Iliev,Tonka Vasileva,Veselin Bivolarski,Asya Petrova Viraneva,Ivan Bodurov,Maria Marudova,Temenuzhka Yovcheva / Language(s): Bulgarian Issue: 5/2018

Fructosyltransferases catalyze the synthesis of Levan type polysaccharides in the presence of sucrose in the reaction medium. In the presence of acceptors (maltose, isomaltose, lactose, fructose) and fructose donor sucrose, they synthesize oligosaccharides with a degree of polymerization DP 3 - 5 monosaccharide residues that have prebiotic potential. In the present study, the fructosyltransferase from Leuconostoc mesenteroides Lm17 strain is immobilized on a multilayer polysaccharide structure composed of chitosan and xanthan. The layers were applied onto pre-loaded corn root cans of polylactic acid. The resulting composite films were investigated for the degree of immobilization of the enzyme and the ability to synthesize fructan on the surface of the film. The activity of immobilized enzyme film was found 0.73 U/mg in the resulting films. In carrying out an enzymatic reaction in the presence of over 10 % sucrose, a hydrolysis and transferase reaction was established by which a polysaccharide was synthesized in both the solution and the membrane. Surface morphology of multilayer films is investigated using the Nanosurf Flex AFM. The values of the average roughness were obtained. It is found that it increases with increasing number of layers, regardless of their sequence.

On the Possibility to Analyze Ambient Noise Recoeded by a Mobile Device Through the H / V Spectral Ratio Technique

Author(s): Dragomir Gospodinov,Delko Zlatanski,Boyko Ranguelov,Alexander Kandilarov / Language(s): English Issue: 5/2018

The analysis of the spectral properties of ambient seismic noise has recently turned to be a promising approach in the study of site effects impact on seismic hazard. In the present paper we present some results from our investigation on the possibility to use mobile devices to record analyze seismic noise through the examination of the horizontal to vertical (H/V) spectral ratio. The results were compared to the ones, obtained by the application of professional seismological equipment, a velocimeter of type GBV-316 of the GEOSIG company. Some divergence of the results from the mobile device and those from GBV-316 were identified, revealing that the application of a mobile device in this case is questionable.

The Effect of Hydrocollids Concentration on the Physical Properties of Gluten-Free Cake

Author(s): D. Iserliyska,Gabor Ivan Zsivanovits,Maria Marudova / Language(s): English Issue: 5/2018

In the present study the influence of hydrocolloids addition at different concentration (0.45, 0.9 and 1.5 %) to gluten-free cakes was studies and the quality of cakes was investigated. Based on investigation results it was found that, with the addition of xanthan – guar gum blend at concentrations 1.5 % (50:50 ratio) to the rice flour favorable results were achieved, represented by increased specific volume, lower loss of weight and decreased hardness of the products if compared to the control. The results from the sensory test indicated that all of the sample formulations produced high consumer acceptance rating (x>6). Additionally the use of xanthan – guar gum blend (1.5 %) as well as xanthan gum (0.9 %) showed a trend to retard the staling of rice cakes in the interval between 24 and 96 hour of the storage. The enthalpy values of cakes with hydrocolloids added were lower than the control sample for the whole period of 140 h of storage.

Distribution of Lamb Waves in AlScN Resonator Structures

Author(s): Boris Nedyalkov,Evgenia Valcheva / Language(s): English Issue: 5/2018

In this paper we present the results of a simulated model of resonator device comprised of AlScN/6H-SiC piezo-layers for use in RF electronic circuits. The device uses the piezoelectric effect and Al electrode gratings to generate Lamb waves with great frequencies. The small mechanical impedance, micrometric size and good electromechanical characteristics make it especially suited for the manufacturing of RF band-pass filters. Moreover, because of the mechanics of the Lamb Wave Resonator (LWR) device, it can allow for multiple resonant frequencies to be used with the same configuration. Here we show the basic characteristics of one such system using Al0,91Sc0,09N piezo-active layer and base layer from hexagonal SiC.

Изследователски практикум

Author(s): Ivelina Dimitrova,Gosho Goev,Savina Georgieva,T. Tsanova,L. Ivanova,Borislav Georgiev / Language(s): Bulgarian Issue: 5/2018

The work presents an approach in which an experimental assignment is carried out similarly to a scientific study in the frames of a student lab course. The approach aims to meet the students with the basic stages in experimental studies and to instill in them the excitement of shared “discoveries”. It was first tested in the frames of a General physics lab course with 76 freshman students majoring in Molecular biology. In contrast to classical labs, the proposed approach involved: application of the scientific method, selecting an applicable experimental method, out-of-class teamwork, drawing conclusions from the obtained results and presenting the results in public. The selected assignments can be completed with common materials, simple equipment and smartphone applications. The current work summarizes the observation of the involved faculty and the results from a survey among the students. The stages that the students had most difficulty with were identified as the following: setting up a hypothesis, modeling the physical processes, processing the results and drawing conclusions from them, and cooperating with team members. It was concluded that the proposed educational approach can be inspiring and useful for the development of the students’ critical thinking and creativity. Furthermore, it is widely applicable to students at different levels of competence.

Програмата Hot Potatoes – интерактивност в обучението

Author(s): Aneta Dailova / Language(s): Bulgarian Issue: 5/2018

The development of electronic tests and exercises is part of the didactic test theory. Tests can be successfully applied across all disciplines to determine the entry level, to verify and control the learning contents, and to report outcomes at the end of the training period.The “Hot Potatoes” program offers the opportunity to use several didactic models: JQuiz – JakeCuiz, JCloze – JackClose, CrossJackros, JMix – JayMix, JMatch – JeMech. The use of the program is fully in line with the contemporary understanding of didactic tests for learning purposes. The logical arrangement of the exercises is in compliance with the curriculum and based on the chronological principle. The electronic exercises of the “Hot Potatoes” program are used for revision exercises, homework assignments, error correction, performance comparison and more.

Използване на поетични текстове в съвременните учебни системи по испански език

Author(s): Veneta Sirakova / Language(s): Bulgarian Issue: 5/2018

After abolishing the grammar-translation method in foreign language teaching, the use of poetry in Spanish language textbooks is considerably restricted. Despite the efforts of modern Spanish academics to rehabilitate it theoretically as a valuable didactic tool in the acquisition of principal language skills, the authors of recent Spanish language textbooks (for speakers of other languages) continue to accord it a secondary function, to apply it as illustrative material or to totally ignore it. The present article sets the aim of demonstrating the main tendencies in using poetic texts in Spanish language teaching on the basis of a comparative analysis of a considerable corpus of textbooks, published and edited after 2000.

Reflections on Approaches to Language and Culture and their Relevance to Publishing and Librarianship during Sultan Abdülhamid II Period: Istanbul University’s Rare Books Library

Author(s): Pervin Bezirci / Language(s): English Issue: 5/2018

As a result of the developments in the fields of technology, communication and transportation, the world is becoming more and more diverse. Consequently, it is natural that in almost every society, the profile of the library user from different cultures is also importaant. Libraries, having indisputable signiuficance in the educational and cultural development of individuals, are those institutions that make all the effort to provide equal opportunities for their members.In this study, the importance of linguistic and cultural diversity from the perspective of library services has been briefly examined. Some reflections on the language policies during the reign of Abdulhamid II on publication and library life are presented. The language structure of the Yıldız Palace Library Collection, which belongs to the period of Abdülhamid II and is still in the Rare Books Library of Istanbul University is briefly evaluated.

В памет на проф. Kамен Михайлов

Author(s): Panayot Karagiozov / Language(s): Bulgarian Issue: 5/2018

Die „Säuberung“ der Universitäten 1938 am Beispiel der Wiener Rechtswissenschaftlichen Fakultät

Author(s): Kamila Staudigl-Ciechowitz / Language(s): German Issue: 2/2018

The following contribution commemorates the racially- and politically-motivated expulsions of academic teachers and students in 1938 at the University of Vienna. Though these expulsions took place in the weeks after the “Anschluss” in March 1938, anti-Semitic occurrences were common at Austrian universities long before 1938. From 1918 on anti-Semitic tendencies at the universities were getting stronger, in spring 1938 Jewish as well as political opponent scholars and students were forced to leave the Austrian universities due to national socialistic ideology. The paper shows the expulsions from a legal point of view, stressing the significance of the laws that where enacted between 1934–1938 by the austrofacist government.

The Role of Computer Animation in Mathematics Teaching

Author(s): Sergey Larin,Valeriy Mayer / Language(s): English Issue: 6/2018

The article is devoted to the role, importance, and use of animated drawings created on computer screens in GeoGebra platform for Mathematics teaching at schools and Universities. The use of this platform introduces a new kind of visibility in Mathematics learning, which entails not only an increased interest to the subject, but also promotes understanding and stronger perception of abstract material. In addition, an opportunity appears to remove computing difficulties, since the calculations are done by the computer. The user becomes a manager of computing and this saves time, but also allows acquiring new competence in useful digital technologies in education. Animated graphics help to realize experiments, to notice new patterns, to suggest solutions of mathematical problems and to illustrate them successfully. All that is of great importance for the formation of the new generation, called upon the development of the Russian digital economy.

Управление на софтуерно дефинираните мрежи с Floodlight Controller

Author(s): Rumen Todorov / Language(s): Bulgarian Issue: 6/2018

The basic idea for software-defined networks (SDN) is the separation of systems that control the network from systems the data plane. This defines a layer of program control and control of the whole network (control layer). The SDN controller manages the entire network, receives instructions and instructions from the application layer and relays them to the network components. The controller retrieves network infrastructure information – a infrastructure layer – and returns it back to the application layer. In this article we will present the basic architecture and features of the Floodlight controller. We test different topologies of the Mininet network simulator, interaction between virtual machines, adding and intercepting OpenFlow flows from the Wireshark network analyzer.

Семинар-практикумът в неформалното обучение – възможност и развитие на умения и творчество през призмата на физиката

Author(s): Assen Pashov,S. Yordanova-Dyulgerova,Bonka Karaivanova-Dolchinkova,R. Draganova-Hristova / Language(s): Bulgarian Issue: 6/2018

The report presents a seminar-practicum, including theory, observation and experimental activity, applicable to teaching Physics and astronomy in Grade 7. Through separate work centers, under the leadership of lecturers and students from Sofia University “St. Kliment Ohridski” experimental tasks, such as making a spectroscope, eye model, color world, vibration and sound, have been accomplished. This ceminar-practicum as a non-formal teaching and learning gives opportunities for students to develop their creative potential, and enrich the theory and practice in Physics and Astronomy.

Професионалната учебна общност

Author(s): Stanimira Todorova Savova / Language(s): Bulgarian Issue: 6/2018

This article aims to present our work in the established educational community created in the school, the goals we have set ourselves, the activities carried out, the results obtained and the conclusions drawn. When comparing the results obtained, the test method and the questionnaire were used.

Определяне на земното ускорение: експериментална задача

Author(s): Mariana Anastassova / Language(s): Bulgarian Issue: 6/2018

Easy way for experimental determination of the Earth acceleration g is described.

Роботика за начинаещи ентусиасти

Author(s): Daniela Uzunova,Boris Velkovski,Ilko Simeonov,Vladislav Shabanski,Dimitar Kolev / Language(s): Bulgarian Issue: 6/2018

A Club of robotics was established in the High School of Mathematics in Pleven. This initiative gives good results. The activities of the students in the Club are described in brief in the present article.

Дисциплината „произход на живота и теории за еволюцията“ в професионалната подготовка на учителя по биология

Author(s): Isa Hadjiali / Language(s): Bulgarian Issue: 6/2018

The main goal of this report is to conduct a substantial analysis of some fundamental normative documents in the Secondary and university systems of education. A vector model of the professional competency of the biology teacher has been modeled on the grounds of this theoretical analysis. The concept of the discipline “The origin of life and theories of evolution” in the context of the standards of the biology teacher training at the University of Sofia is well described here. A piece of the curriculum in the form of topics and their descriptions is presented, as well.

Design and Docking Studies of His-Leu Analoguesa Potentioal Ace Inhibitor

Author(s): Atanas Chapkanov,Tatyana Dzimbova,Rumen Georgiev / Language(s): English Issue: 6/2018

Bioactive peptides are protein fragments that have a positive impact on body functions and may ultimately influence health. Angiotensin-converting enzyme plays an important role in the control of arterial blood pressure. The main action of Angiotensin II is to maintain blood pressure and fluid balance in the body. It is obtained from the precursor under catalytic action of angiotensin-converting enzyme (ACE). In order to control (inhibit) the action of the ACE different inhibitors were proposed and some of them are already in use in the clinic. In the present investigation we design and docking studies of fife new potential ACE inhibitors. Three of the proposed analogues have a potential to be ACE inhibitors, as they bind to the enzyme stronger than His-Leu. The studied peptides may form as a basis for the design of new compounds and will be synthesized and biologically tested.

Културна комуникация и национална консолидация

Author(s): Myumyun Tahirov / Language(s): Bulgarian Issue: 6/2018

The thesis of this article is that cultural communication is a decisive factor in the formation and consolidation of a nation. Society and communication occur simultaneously; both phenomena can not exist without each other.Each cultural communication system implies the emergence of new nations as it makes it possible to identify the individual with the group/community based on common past, territory, symbols, language and political and legal institutions. The lack of such a system and the existence of the so-called “ethnic syndrome” hinders the cultural development of entire societies, as individuals and communities do not receive the information they need for themselves and for their activity. This prevents communication, and, consequently, national consolidation.Finally, an own definition of the concept of “nation” is proposed.

Интерактивни методи в преподаването на граматичен материал в обучението по английски език

Author(s): Desislava Todorova / Language(s): Bulgarian Issue: 6/2018

The purpose of the article is to show how interactive methods can be applied in English language teaching/teaching foreign languages. Short information about interactive methods is given in the beginning. An answer to the question why it is necessary to use such methods is suggested. Communicative Language Teaching approach is commented briefly. An example is given of how interactive methods (group work/pair work) can be applied in teaching narrative tenses and conditional type 3 in English. The aim and the objectives of the lesson are commented and the conclusion from the observations made is shared.