Savica 2020 : diplomski rad

Danas u gradovima živi 50% svjetskog stanovništva, a do 2050. godine ta će brojka iznositi oko 70%. Uz kontinuiran rast gradova, i poljoprivredne zone morat će rasti kako bi prehranile oko dvije trećine populacije. Povećat će se udaljenost između mjesta proizvodnje i mjesta kupovine namirnica. Uz problem ekonomičnosti, pojavit će se i problem nedostatka površina pogodnih za uzgoj. Diplomski rad se bavi problematikom uzgoja vlastite hrane u gradovima. To rješenje bi omogućilo dostupnost svježih namirnica na mjestu uzgoja, smanjilo svakodnevne troškove stanovnika te troškove transporta te potaknulo interakcije među stanovnicima

Savica 2020 : diplomski rad

Danas u gradovima živi 50% svjetskog stanovništva, a do 2050. godine ta će brojka iznositi oko 70%. Uz kontinuiran rast gradova, i poljoprivredne zone morat će rasti kako bi prehranile oko dvije trećine populacije. Povećat će se udaljenost između mjesta proizvodnje i mjesta kupovine namirnica. Uz problem ekonomičnosti, pojavit će se i problem nedostatka površina pogodnih za uzgoj. Diplomski rad se bavi problematikom uzgoja vlastite hrane u gradovima. To rješenje bi omogućilo dostupnost svježih namirnica na mjestu uzgoja, smanjilo svakodnevne troškove stanovnika te troškove transporta te potaknulo interakcije među stanovnicima

Computational Study of Electronic Influence of Guanidine Substitution on Diels-Alder Reactions of Heterocyclic Dienes

Quantum-chemical calculations of cycloaddition properties of cyclic heterodienes substituted with guanidine functionality were carried out. Molecular and electronic structures of series of dienes (pyrrole, furan, thiophene, isoindole and 1,3-butadiene) were calculated and reactivity order established on the basis of FMO theory. Transition state calculations of model [4+2] cycloaddition reaction with acetylene indicate that guanidine substitution influences reaction barriers in moderate extent (up to ~4 kcal mol–1). The substitution position plays an important role on the sign and magnitude of the effect and protonation of nitrogen possessing substituents increases reactivity of dienes. This work is licensed under a Creative Commons Attribution 4.0 International License

Anion-Controlled Synthesis of Novel Guanidine-Substituted Oxanorbornanes

The cycloaddition of simple alkyl-substituted guanidine derivatives is an interesting approach toward polycyclic superbases and guanidine-based organocatalysts. Due to the high nucleophilicity of guanidines, an aza-Michael reaction with dienophiles is more common and presents a huge obstacle in achieving the desired synthetic goal. Our preliminary investigations indicated that the proton could act as a suitable protecting group to regulate the directionality of the reaction. To investigate the role of the protonation state and type of anion, the reactivity of furfuryl guanidines with dimethyl acetylenedicarboxylate was explored. Furfuryl guanidines showed a strong reaction dependence on the nucleophilicity of the counterion and the structure of guanidine. While the reaction of DMAD with the guanidinium halides provided products of an aza-Michael addition, Diels–Alder cycloaddition occurred if non-nucleophilic hexafluorophosphate salts were used. Depending on the structure and the reaction conditions, oxanorbornadiene products underwent subsequent intramolecular cyclization. A tendency toward intramolecular cyclization was interpreted in terms of the pKa of different positions of the guanidine functionality in oxanorbornadienes. New polycyclic guanidines had a slightly decreased pKa in acetonitrile and well-defined geometry suitable for the buildup of selective sensors

Kinetics of amyloid fibril formation in the presence of metal ions and low-molecular-weight compounds

Proteins are prone to structural changes due to their marginal stability. There are multiple pathways of structural rearrangements leading to misfolding and aggregation among which amyloids stand out as highly ordered and remarkably stable forms which appear to be a global minimum of protein free energy landscape of all proteins. In vitro studies on different proteins show that destabilizing conditions that favor the state of molten globule are likely to lead to ordered fibril formation. The presence of various organic and inorganic molecules was reported to affect amyloid fibril formation, eighter as stimulators or inhibitors. We investigated the formation of amyloid fibrils of human serum albumin, ovalbumin and papain in the presence of metal ions, as well as low-molecular-weight compounds. Proteins were incubated in destabilizing conditions optimized to prolong the solubility of molten globule state and induce amyloid-like structural changes. The effects of inorganic and organic additives on fibrillation process were monitored using Thioflavin T fluorescence, 8-Anilinonaphthalene-1-sulfonic acid fluorescence, Attenuated total reflection Fourier-transform infrared spectroscopy, electrophoretic and microscopy techniques. Our results show that the kinetics of amyloid formation is dependent on the presence of iron, copper, zinc and aluminum salts, as well as different lipophilic lowmolecular- weight compounds. While some compounds act as complete inhibitors of fibrillation, others increase the rate of fibrillation process and promote the formation of mature fibrils