Оптимізація перевезень сільськогосподарської продукції

UK: В работе сделана попытка оптимизировать процесс перевози собранного урожая с целью минимизации себестоимости перевозок. EN: An attempt to optimize the vehicular process of the collected harvest with the purpose of minimization ofprime price of transportation is done in this

Optical Properties of Plasmonic Nanostructures for Bio-Imaging and Bio-Sensing Applications

Kravets, Vira V. (Ph.D., Physics) Optical properties of plasmonic nanostructures for bio-imaging and bio-sensing applications Dissertation directed by Associate Professor Anatoliy Pinchuk. ABSTRACT This dissertation explores the physics of free electron excitations in gold nanoparticle chains, silver nanoparticle colloids, and thin gold films. Electron excitations in nanostructures (surface plasmons, SP) are responsible for unique optical properties, which are applied in bio-sensing and bio-imaging applications. For gold nanoparticle chains, the effect of SP on resonance light absorption was studied experimentally and theoretically. Mainly, how the spectral position of the absorption peak depends on inter-particle distances. This dependence is used in “molecular rulers”, providing spatial resolution below the Rayleigh limit. The underlying theory is based on particle interaction via scattered dipole fields. Often in literature only the near-field component of the scattered field is considered. Here, I show that middle and far fields should not be neglected for calculation of extinction by particle chains. In silver nanoparticles, SP excitations produce two independent effects: (a) the intrinsic fluorescence of the particles, and (b) the enhancement of a molecule’s fluorescence by a particle’s surface. The mechanism of (a) is deduced by studying how fluorescence depends on particle size. For (b), I show that fluorescence of a dye molecule on the surface of a nanoparticle is enhanced, when compared to that of the free-standing dye. I demonstrate that the dye’s fluorescent quantum yield is dependent on the particle’s size, making labeled silver nanoparticles attractive candidates as bio-imaging agents. Labeled nanoparticles are applied to cell imaging, and their bio-compatibility with two cell lines is evaluated here. Finally, in gold films under attenuated total internal reflection (ATR) conditions, the SP create a propagating wave (SP-polariton, SPP) when coupled with the incident light. Because of the sensitivity of SPPs to the medium adjacent to the gold film surface, they are widely applied in bio-sensing applications. A toolbox for the description of sputter-deposited gold films is presented here: it employs three experimental techniques (ATR, transmittance and atomic force microscopy) in combination with the effective medium theory for double-layered film model. Our findings have allowed for the avoidance of superficial fitting parameters in our model

Pedagogical Design of the Technology of Students’ Multicultural Competence at Higher Education Institutions

Aim. The aim of the research is to justify the theoretical and methodological bases of multicultural education and verify experimentally the efficiency of the pedagogical technology of forming students’ multicultural competence at higher education institutions. Methods. The study reviews the changes in the levels of students’ multicultural competence. The methodological bases of the study are theories of language multicultural education, the unity of language and culture, multi-perspective learning, “cultural differences,” social learning, neo-Freudian theory, self-determination theory, developmental learning theory. Results. The realisation of the ideas of multiculturalism has a positive effect on the harmonious development, cultivates a tolerant attitude to other ethnic groups and peoples, promotes good neighbourly relations, effective conflict resolution, intercultural dialogue and mutual understanding. Acquiring these characteristics, students entirely understand national and universal values, and are able to interact constructively in the modern multicultural world at a sustainable level. Conclusions. The implementation of the developed pedagogical conditions and the author’s pedagogical technology of forming students’ multicultural competence at higher education institutions contributed to a significant increase in the levels of their multicultural competence. This was confirmed by statistical changes in the level of students’ multicultural competence of the experimental group compared to the control group: the number of students with stable (by 34,3%) and situational (by 12,7%) levels significantly increased, the number of students with fragmentary level decreased (by 47%). Thus, the obtained results prove that the developed pedagogical technology is effective for forming students’ multicultural competence

Beta-cell Intrinsic Dynamics Rather than Gap Junction Structure Dictates Subpopulations in the Islet Functional Network

Diabetes is caused by the inability of electrically coupled, functionally heterogeneous -cells within the pancreatic islet to provide adequate insulin secretion. Functional networks have been used to represent synchronized oscillatory [Ca2+] dynamics and to study -cell subpopulations, which play an important role in driving islet function. The mechanism by which highly synchronized -cell subpopulations drive islet function is unclear. We used experimental and computational techniques to investigate the relationship between functional networks, structural (gap-junction) networks, and intrinsic -cell dynamics in slow and fast oscillating islets. Highly synchronized subpopulations in the functional network were differentiated by intrinsic dynamics, including metabolic activity and KATP channel conductance, more than structural coupling. Consistent with this, intrinsic dynamics were more predictive of high synchronization in the islet functional network as compared to high levels of structural coupling. Finally, dysfunction of gap junctions, which can occur in diabetes, caused decreases in the efficiency and clustering of the functional network. These results indicate that intrinsic dynamics rather than structure drive connections in the functional network and highly synchronized subpopulations, but gap junctions are still essential for overall network efficiency. These findings deepen our interpretation of functional networks and the formation of functional sub-populations in dynamic tissues such as the islet

Reduced synchroneity of intra-islet ca²⁺ oscillations in vivo in <i>Robo</i>-deficient β cells

The spatial architecture of the islets of Langerhans is hypothesized to facilitate synchronized insulin secretion among β cells, yet testing this in vivo in the intact pancreas is challenging. Robo βKO mice, in which the genes Robo1 and Robo2 are deleted selectively in β cells, provide a unique model of altered islet spatial architecture without loss of β cell differentiation or islet damage from diabetes. Combining Robo βKO mice with intravital microscopy, we show here that Robo βKO islets have reduced synchronized intra-islet Ca2+ oscillations among β cells in vivo. We provide evidence that this loss is not due to a β cell-intrinsic function of Robo, mis-expression or mis-localization of Cx36 gap junctions, or changes in islet vascularization or innervation, suggesting that the islet architecture itself is required for synchronized Ca2+ oscillations. These results have implications for understanding structure-function relationships in the islets during progression to diabetes as well as engineering islets from stem cells