scholarly journals Nucleotide Interaction with Chitosan Layer Deposited on Fumed Silica Surface: Practice and Theory towards Establishing the Mechanism at the Molecular Level

2020 ◽  
Author(s):  
Tetyana Budnyak ◽  
Nataliya Vlasova ◽  
Lyudmila P. Golovkova ◽  
Olga Markitan ◽  
Glib V. Baryshnikov ◽  
...  
Keyword(s):  
Fumed Silica ◽  
Electrostatic Interactions ◽  
Silica Surface ◽  
Gene Transfection ◽  
Decisive Role ◽  
Formation Constants ◽  
Surface Complex ◽  
Complex Formation Constants ◽  
Efficient Gene

The growing interest in gene therapy is coupled to the strong need for the development of safe and efficient gene transfection vectors. A composite based on chitosan and fumed silica has been found to be a prospective gene delivery carrier. This study presents an investigation of the nature of the bonds between a series of mono-, di- and triphosphate nucleotides with a chitosan layer deposited on a fumed silica surface. It was observed that the adsorption of most of the studied nucleotides is determined by the formation of one surface complex. Experimentally measured surface complex formation constants (logK) of the nucleotides were found to be in range 2.69–4.02 which is higher than that for the orthophosphate (2.39). Theoretically calculated nucleotide complexation energies for chitosan deposited on the surface range from 11.5 to 23.0 kcal·mol<sup>–1</sup> in agreement with experimental data. The adsorption of nucleotides was interpreted using their calculated speciation in aqueous solution. Based on the structures of all optimized complexes determined from quantum-chemical PM6 calculations, electrostatic interactions between the surface-located NH<sub>3</sub><sup>+</sup> groups and –PO<sub>3</sub>H<sup>–</sup>–/–PO<sub>3</sub><sup>2-</sup> fragments of the nucleotides was identified to play the decisive role in the adsorption mechanism. The saccharide fragment of monophosphates also plays an important role in the binding of the nucleotides to chitosan through the creation of hydrogen bonds; in the case of di- and triphosphates the role of the saccharide fragment decreases significantly.

scholarly journals Nucleotide Interaction with Chitosan Layer Deposited on Fumed Silica Surface: Practice and Theory towards Establishing the Mechanism at the Molecular Level

2020 ◽  
Author(s):  
Tetyana Budnyak ◽  
Nataliya Vlasova ◽  
Lyudmila P. Golovkova ◽  
Olga Markitan ◽  
Glib V. Baryshnikov ◽  
...  
Keyword(s):  
Fumed Silica ◽  
Electrostatic Interactions ◽  
Silica Surface ◽  
Gene Transfection ◽  
Decisive Role ◽  
Formation Constants ◽  
Surface Complex ◽  
Complex Formation Constants ◽  
Efficient Gene

The growing interest in gene therapy is coupled to the strong need for the development of safe and efficient gene transfection vectors. A composite based on chitosan and fumed silica has been found to be a prospective gene delivery carrier. This study presents an investigation of the nature of the bonds between a series of mono-, di- and triphosphate nucleotides with a chitosan layer deposited on a fumed silica surface. It was observed that the adsorption of most of the studied nucleotides is determined by the formation of one surface complex. Experimentally measured surface complex formation constants (logK) of the nucleotides were found to be in range 2.69–4.02 which is higher than that for the orthophosphate (2.39). Theoretically calculated nucleotide complexation energies for chitosan deposited on the surface range from 11.5 to 23.0 kcal·mol<sup>–1</sup> in agreement with experimental data. The adsorption of nucleotides was interpreted using their calculated speciation in aqueous solution. Based on the structures of all optimized complexes determined from quantum-chemical PM6 calculations, electrostatic interactions between the surface-located NH<sub>3</sub><sup>+</sup> groups and –PO<sub>3</sub>H<sup>–</sup>–/–PO<sub>3</sub><sup>2-</sup> fragments of the nucleotides was identified to play the decisive role in the adsorption mechanism. The saccharide fragment of monophosphates also plays an important role in the binding of the nucleotides to chitosan through the creation of hydrogen bonds; in the case of di- and triphosphates the role of the saccharide fragment decreases significantly.

The main directions of educational policy of Finland

2020 ◽  
Vol 11 (2) ◽  
pp. 6-13
Author(s):  
K. E. Stupak ◽  
Keyword(s):  
Higher Education ◽  
Education Policy ◽  
Education System ◽  
Decisive Role ◽  
The State ◽  
Vocational Education And Training ◽  
State Education Policy ◽  
Role Of The State ◽  
State Education

The article deals with analyzing the main streams of the education policy in Finland, which reflect the relationship between a person and society in modern socio–economic conditions. Such policy directs the system of education to change the person and his mind himself. Finland using its education system, has long before been concerned about preparing people for the future by reforming approaches to teaching in schools and higher education institutions. As a result, it has achieved world–wide recognition and top positions in various ratings have resulted. Therefore, today there is a great interest of scientists in certain issues of education functioning in Finland. Thus, G. Androshchuk, V. Butova. I. Zhernokleeva, T. Pushkareva and others study in their works the purpose and decisive role of Finland's education policy in the development of the education system. S. Grinyuk and V. Zagvozdkin pay attention to the practical the steps of reforming the Finnish system of education. T. Drobyshevsk investigates the system of providing educational services in Finland as a sector of knowledge production. L. Volynets, P. Kukharchuk consider the principles of the state education policy of Finland. L. Smolskaya examines the role of the state policy in implementing the "Finnish phenomenon"; P. Basyliuk and Yu. Kulykova, focus attention on the study of the evolution of the system of higher education in Finland; O. Scherbak reveals peculiarities of vocational education and training.

Democratization in Serbia: An Analysis of Rational Choice and Structuralist Explanations

2015 ◽  
Author(s):  
Dunja Apostolov-Dimitrijevic
Keyword(s):  
Rational Choice ◽  
Path Dependence ◽  
Theoretical Perspective ◽  
Political Leadership ◽  
Decisive Role ◽  
The Other ◽  
Internal Factors ◽  
Transitional Societies ◽  
The Face

This paper explains political democratization in Post-Milosevic Serbia, utilizing two different accounts of the democratization process: one rooted in the rational choice framework and the other in structuralism. While rational choice explains the decisive role of political leadership in overcoming path dependence, the structuralist explanations show the transnational linkages that encourage democratization in the face of domestic setbacks. This particular debate between the two types of explanations represents the larger debate concerning the role of internal factors and external linkages in propelling democratization in transitional societies. The paper concludes by integrating the two sets of explanations offered by each theoretical perspective, in order to develop a coherent understanding of Serbia's democratization.   Full text available at: https://doi.org/10.22215/rera.v9i1.240

Formation of CT complexes and electron transfer from excited molecules of anthracene derivatives to methylviologen in aqueous and micellar media

1987 ◽  
Vol 52 (7) ◽  
pp. 1658-1665
Author(s):  
Viktor Řehák ◽  
Jana Boledovičová
Keyword(s):  
Electron Transfer ◽  
Complex Formation ◽  
Fluorescence Quenching ◽  
Rate Constant ◽  
Formation Constants ◽  
Dynamic Quenching ◽  
Micellar Media ◽  
Complex Formation Constants ◽  
Anthracene Derivatives ◽  
Ct Complexes

Disodium 1,5- and 1,8-anthracenedisulphonate (ADS) and 9-acetylanthracene form coloured CT complexes with methylviologen (MV2+) in aqueous and micellar media. The complex formation constants and molar absorptivities were determined by the Benesi-Hildebrandt method. In the fluorescence quenching, its static component plays the major role. The dynamic quenching component is determined by the rate constant of electron transfer from the S1 state of ADS to MV2+.

scholarly journals The dark-ventral-patch of male red deer, a sexual signal that conveys the degree of involvement in rutting behavior

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Eva de la Peña ◽  
Javier Pérez-González ◽  
José Martín ◽  
Giovanni Vedel ◽  
Juan Carranza
Keyword(s):  
Sexual Behaviors ◽  
Red Deer ◽  
Decisive Role ◽  
Female Mate Choice ◽  
Doñana National Park ◽  
Sexual Signal ◽  
Mating Competition ◽  
Dark Patch ◽  
Rutting Behavior

Abstract Background In polygynous mammals, signalling may play a decisive role in mating behavior, mediating the intensity of male fights and female mate choice. During the rutting season, male red deer may show a visible dark patch in their ventral fur. Recently, this patch has been suggested to act as a flexible sexual signal, due to its relationships with other variables such as age, body size, antler development, volatile compounds, or the competitive environment. The analysis of fur pigmentation at the ventral patch suggests that this might also visually indicate the male intrinsic predisposition to take part in mating competition. Results To assess the possible role of this trait as a communicative signal related to mate competition, we used red deer behavioral observations during the rut in Doñana National Park (Spain) to examine the link between the degree of expression of the dark ventral patch and the rutting activity (assessed from both intra-and-inter-sexual behaviors). Consistent with our predictions, we found in a field study that males with large dark patches showed a higher frequency of rutting behaviors (mainly roaring and flehmen), more interactions with females, and attained larger harem sizes. Conclusions The dark ventral patch was a better predictor of male behavior than antler tines or territory holding, thus standing as a short-term indicator of male willingness to invest in mating competition.

scholarly journals The role of schemas and scripts in pictorial narration

Semiotica ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Ranta
Keyword(s):  
Decisive Role ◽  
Schema Theory ◽  
Virgin Mary ◽  
Levels Of Abstraction ◽  
Event Sequences ◽  
Storage And Retrieval ◽  
Narrative Structures ◽  
Northwestern University ◽  
Generalized Knowledge

Abstract The theoretical debate on the nature of narrative has been mainly concerned with literary narratives, whereas forms of non-literary and especially pictorial narrativity have been somewhat neglected. In this paper, however, I shall discuss narrativity specifically with regard to pictorial objects in order to clarify how pictorial storytelling may be based on the activation of mentally stored action and scene schemas. Approaches from cognitive psychology, such as the work of Schank, Roger C. & Robert P. Abelson. 1977. Scripts, plans, goals and understanding. Hillsdale, NJ: Lawrence Erlbaum; Mandler, Jean Matter. 1984. Stories, scripts, and scenes: Aspects of schema theory. London/Hillsdale, NJ: Lawrence Erlbaum; Schank, Roger C. 1995. Tell me a story: Narrative and intelligence. Evanston, IL: Northwestern University Press, suggest that cognition crucially depends on the storage and retrieval of action scripts or schemata, that is, narrative structures, which may occur at various levels of abstraction. These schemas incorporate generalized knowledge about event sequences, such as the order in which specific events will take place; causal, enabling, or conventionalized relations between these events, and what kind of events occur in certain action sequences. There also are scene schemas that are characterized by spatial rather than temporal relations. Further kinds of schemas seem also to play a decisive role. Drawing upon considerations from schema and script theory, I will focus on some concrete examples of pictorial narration, more specifically depictions of the Annunciation of the Virgin Mary, where narrative schema structures become involved and, indeed, the comprehensibility of the pictures as such presuppose mental script representations.

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