VIS-NIR SPECTROMETRY, SOIL PHOSPHATE EXTRACTION METHODS AND INTERACTIONS OF SOIL ATTRIBUTES

The objective of this study was to evaluate the relationships between the spectra in the Vis-NIR range and the soil P concentrations obtained from the PM and Prem extraction methods as well as the effects of these relationships on the construction of models predicting P concentration in Oxisols. Soil samples' spectra and their PM and Prem extraction solutions were determined for the Vis-NIR region between 400 and 2500 nm. Mineralogy and/or organic matter content act as primary attributes allowing correlation of these soil phosphorus fractions with the spectra, mainly at wavelengths between 450-550, 900-1100 nm, near 1400 nm and between 2200-2300 nm. However, the regression models generated were not suitable for quantitative phosphate analysis. Solubilization of organic matter and reactions during the PM extraction process hindered correlations between the spectra and these P soil fractions. For Prem,, the presence of Ca in the extractant and preferential adsorption by gibbsite and iron oxides, particularly goethite, obscured correlations with the spectra.

INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.

A model for specific interactions of manganese-phthalocyanine in protic media

Extinction coefficients (e) changes of manganese phthalocyanine (Mn-Pc) were studied in different organic solvents and related to solvent polarity scales; (Kosower's values (Z), Dimroth's values (E T), donor numbers (DN) and linear solvation energy relationships (LSER) or linear free energy relationships (LFER));, theoretical molecular orbital calculations and ligand/solvent coordination processes in order to predict molecular interaction with the medium and identification of predominant intermolecular forces.

A FTIR study of the metal-support interactions and hydrogen spillover on Pd/TiO2 and Ni/TiO2

Nickel and palladium dispersed on titania support were submitted to reductive treatment, under hydrogen, at 200 and 500 ºC. After the reductive thermal treatment the materials were exposed to carbon monoxide (10 Torr) and analyzed in the infrared region. The increasing of the electronic density in the metallic d subshell, produced by the reductive thermal treatment, was monitored by the infrared stretching band shift of carbon monoxide adsorbed and it was interpreted as a consequence of the metal-support interactions. The highest effect was observed for Pd/TiO2 system. From the FTIR spectra was also observed that the hydrogen spillover was stronger on Pd/TiO2 than Ni/TiO2 system.

Self-assembly of supermolecular species directed by hydrogen bonding and aromatic π-π stacking interactions

A new Cu(II) trimers, [Cu3(dcp)2(H2O)8]. 4DMF, with the ligand 3,5-pyrazoledicarboxylic acid monohydrate (H3dcp) has been prepared by solvent method. Its solid-state structure has been characterized by elemental analysis, thermal analysis (TGA and DSC), and single crystal X-ray diffraction. X-ray crystallographic studies reveal that this complex has extended 1-D,2-D and 3-D supramolecular architectures directed by weak interactions (hydrogen bond and aromatic π-π stacking interaction) leading to a sandwich solid-state structure.

Epidemiology of Cytochrome P450-mediated Drug-Drug Interactions

Drug-drug interactions (DDIs) comprise an important cause of adverse drug reactions leading to excess hospitalizations. Drug metabolism is catalyzed by 75% by cytochrome P450 (CYP) enzymes and thus they are often involved in pharmacokinetic DDIs. In general, DDIs are studied in randomized controlled clinical trials in selected study populations. The overall aim of the present studies was to perform observational pharmacoepidemiological surveys on CYP-mediated DDIs in diseases important at the population level. The prevalence of co-administrations of four prodrugs (losartan, codeine, tramadol, and clopidogrel), three sulphonylureas (glibenclamide, glimepiride, and glipizide), or two statins (lovastatin and simvastatin) with well established agents altering CYP activity, as well as of statins with fibrates, was studied in Finland utilizing data from a university hospital medication database (inpatients) and the National Prescription Register of the Social Insurance Institution of Finland, Kela (outpatients). Clinical consequences of potential DDIs were estimated by reviewing laboratory data, and information from hospital care and cause-of-death registers. Concomitant use of study substrates with interacting medication was detected in up to one fifth of patients in both hospital and community settings. Potential CYP3A4 interactions in statin users did not manifest in clear adverse laboratory values but pharmacodynamic DDIs between statins and fibrates predisposed patients to muscular toxicity. Sulphonylurea DDIs with CYP2C9 inhibitors increased the risk of hypoglycaemia. CYP3A4 inhibitor use with clopidogrel was not associated with significant changes in mortality but non-fatal thrombosis and haemorrhage complications were seen less often in this group. Concomitant administration of atorvastatin with clopidogrel moderately attenuated the antithrombotic effect by clopidogrel. The overall mortality was increased in CYP3A4 inducer and clopidogrel co-users. Atorvastatin used concomitantly with prodrug clopidogrel seems to be beneficial in terms of total and LDL cholesterol concentrations, and overall mortality compared with clopidogrel use without interacting medication. In conclusion, CYP-mediated DDIs are a common and often unrecognized consequence of irrational drug prescribing.

Viscometric investigations and molecular interactions of some derivatives of 5-substituted indole dihydropyrimidines in mixed organic solvents

Colloid chemical behavior of indole dihydropyrimidines in non-aqueous solvent mixture benzene-methanol of varying composition has been investigated by viscometric measurements at 303K± 0.1. The viscosity of the system increases with the increase in concentration. The Trend Change Point (TCP) values have been determined by intersection of two straight lines, which are found to be dependent on the composition of solvent mixtures. The study confirms that the nature of synthesized compounds agglomerate formed below and above 50% benzene concentration is quite different. The viscometric data have been analyzed in terms of Einstein, Vand, Moulik and Jones-Dole equations. These well known equations have been successfully applied to explain the results of viscosity measurements and the viscometric parameters show that the behavior of compound changes in the proximity of 50% benzene concentration.

Interactions between Polyunsaturated Fatty Acids and Probiotics

The prevalence of inflammatory based diseases has increased in industrialized countries over the last decades. For allergic diseases, two primary hypotheses have been proposed to explain this phenomenon, namely the hygiene and dietary evolution based hypothesis. Particularly, the reduced early exposure to microbes and an increase in the amount of polyunsaturated fatty acids (especially n-6 PUFA) in the diet have been discussed. Often, these two factors have been studied independently, even though both factors have been shown to possess potential health benefits and their mode of action to share similar mechanisms. The hypothesis of the present study was that demonstrate that PUFA and probiotics are not separate entities as such but do interact with each other. In the present study, we investigated whether maternal diet and atopic status influence the PUFA composition of breast milk and serum fatty acids of infants, and whether the fatty acid absorption and utilization of infant formula fatty acids is affected by supplementation of infant formula with probiotic bacteria (Lactobacillus GG and Bifidobacterium lactis Bb-12). Moreover, we investigated the mechanisms by which different PUFA influence the physicochemical and functional properties of probiotics as well as functionality of epithelial cells in vitro. We demonstrated a carry-over effect of dietary fatty acids from maternal diet via breast milk into infants’ serum lipid fatty acids. Our data confirmed the previously shown allergy –related PUFA level imbalances, though it did not fully support the impaired desaturation and elongation capacity hypothesis. We also showed that PUFA incorporation into phospholipids of infants was influenced by probiotics in infant formula in a strain dependent manner. Especially,Bifidobacterium lactis Bb-12 in infant formula promoted the utilization of n-3 PUFA. Mechanistically, we demonstrated that probiotics (Lactobacillus GG, Lactobacillus casei Shirota and Lactobacillus bulgaricus) did incorporate and interconvert exogenous free PUFA in the growth medium into bacterial fatty acids strain and PUFA dependently. In general, high concentrations of free PUFA inhibited the growth and mucus adhesion of probiotics, whereas low concentrations of specific long chain PUFA were found to promote the growth and mucus adhesion of Lactobacillus casei Shirota. These effects were paralleled with only minor alterations in hydrophobicity and electron donor – electron acceptor properties of lactobacilli. Furthermore, free PUFA were also demonstrated to alter the adhesion capacity of the intestinal epithelial cells; n-6 PUFA tended to inhibit the Caco-2 adhesion of probiotics, whereas n-3 PUFA had either no or minor effects or even promote the bacterial adhesion (especially Lactobacillus casei Shirota) to PUFA treated Caco-2 cells. The results of this study demonstrate the close and bilateral interactions between dietary PUFA and probiotics. Probiotics were shown to influence the absorption and utilization of dietary PUFA, whereas PUFA were shown to alter the functional properties of both probiotics and mucosal epithelia. These findings suggest that a more thorough understanding of interactions between PUFA and intestinal microbiota is a prerequisite, when the beneficial effects of new functional foods containing probiotics are designed and planned for human intervention studies.

The Significance of Hydrogen Bonding Interactions in the Cleavage of RNA

RNA is essential for all living organisms. It has important roles in protein synthesis, controlling gene expression as well as catalyzing biological reactions. Chemically RNA is a very stable molecule, although in biological systems many agents catalyze the cleavage of RNA, such as naturally occurring enzymes and ribozymes. Much effort has been put in the last decades in developing highly active artificial ribonucleases since such molecules could have potential in the therapeutic field and provide tools for molecular biology. Several potential catalysts have emerged, but usually detailed cleavage mechanism remains unresolved. This thesis is aimed at clarifying mechanistic details of the cleavage and isomerization of RNA by using simpler nucleoside models of RNA. The topics in the experimental part cover three different studies, one concerning the mechanism of catalysis by large ribozymes, one dealing with the reactivity of modified and unmodified RNA oligonucleotides and one showing an efficient catalysis of the cleavage and isomerization of an RNA phosphodiester bond by a dinuclear metal ion complex. A review of the literature concerning stabilization of the phosphorane intermediate of the hydrolysis and isomerization of RNA phosphodiester bond is first presented. The results obtained in the experimental work followed by mechanistic interpretations are introduced in the second part of the thesis. Especially the significance of hydrogen bonding interactions is discussed.

Astringent Food Compounds and Their Interactions with Taste Properties

Astringency is traditionally thought to be induced by plant tannins in foods. Because of this current research concerning the mechanism of astringency is focused on tannin‐protein interactions and thus on precipitation, which may be perceived by mechanoreceptors. However, astringency is elicited by a wide range of different phenolic compounds, as well as, some non‐phenolic compounds in various foods. Many ellagitannins or smaller compounds that contribute to astringent properties do not interact with salivary proteins and may be directly perceived through some receptors. Generally, the higher degree of polymerization of proanthocyanidins can be associated with more intense astringency. However, the astringent properties of smaller phenolic compounds may not be directly predicted from the structure of a compound, although glycosylation has a significant role. The astringency of organic acids may be directly linked to the perception of sourness, and this increases along with decreasing pH. Astringency can be divided into different sub‐qualities, including even other qualities than traditional mouth‐drying, puckering or roughing sensations. Astringency is often accompanied by bitter or sour or both taste properties. The different sub‐qualities can be influenced by different astringent compounds. In general, the glycolysation of the phenolic compound results in more velvety and smooth mouthdrying astringency. Flavonol glycosides and other flavonoid compounds and ellagitannins contribute to this velvety mouthdrying astringency. Additionally, they often lack the bitter properties. Proanthocyanidins and phenolic acids elicit more puckering and roughing astringency with some additional bitter properties. Quercetin 3‐O‐rutinoside, along with other quercetin glycosides, is among the key astringent compounds in black tea and red currants. In foods, there are always various other additional attributes that are perceived at the same with astringency. Astringent compounds themselves may have other sensory characteristics, such as bitter or sour properties, or they may enhance or suppress other sensory properties. Components contributing to these other properties, such as sugars, may also have similar effects on astringent sensations. Food components eliciting sweetness or fattiness or some polymeric polysaccharides can be used to mask astringent subqualities. Astringency can generally be referred to as a negative contributor to the liking of various foods. On the other hand, perceptions of astringent properties can vary among individuals. Many genetic factors that influence perceptions of taste properties, such as variations in perceiving a bitter taste or variations in saliva, may also effect the perception of astringency. Individuals who are more sensitive to different sensations may notice the differences between astringent properties more clearly. This may not have effects on the overall perception of astringency. However, in many cases, the liking of astringent foods may need to be learned by repetitive exposure. Astringency is often among the key sensory properties forming the unique overall flavour of certain foods, and therefore it also influences whether or not a food is liked. In many cases, astringency may be an important sub‐property suppressed by other more abundant sensory properties, but it may still have a significant contribution to the overall flavour and thus consumer preferences. The results of the practical work of this thesis show that the astringent phenolic compounds are mostly located in the skin fractions of black currants, crowberries and bilberries (publications I–III). The skin fractions themselves are rather tasteless. However, the astringent phenolic compounds can be efficiently removed from these skin fractions by consecutive ethanol extractions. Berries contain a wide range of different flavonol glycosides, hydroxycinnamic acid derivatives and anthocyanins and some of them strongly contribute to the different astringent and bitterness properties. Sweetness and sourness are located in the juice fractions along with the majority of sugars and fruit acids. The sweet and sour properties of the juice may be used to mask the astringent and bitterness properties of the extracts. Enzymatic treatments increase the astringent properties and fermented flavour of the black currant juice and decrease sweetness and freshness due to the effects on chemical compositions (IV). Sourness and sweetness are positive contributors to the liking of crowberry and bilberry fractions, whereas bitterness is more negative (V). Some astringent properties in berries are clearly negative factors, whereas some may be more positive. The liking of berries is strongly influenced by various consumer background factors, such as motives and health concerns. The liking of berries and berry fractions may also be affected by genetic factors, such as variations in the gene hTAS2R38, which codes bitter taste receptors (V).

INTERACTIONS OF BIOCHAR AND ORGANIC COMPOUND FOR SEEDLINGS PRODUCTION OF Magonia pubescens A. St.-Hil.

ABSTRACTThe objective of this study was to test the hypothesis that biochar, applied with cattle manure, promotes better development of seedlings of Magonia pubescens St. Hil. The experiment was conducted at the State University of Mato Grosso, Nova Xavantina, Brazil, in 2011. We used a completely randomized design, with twelve treatments and three replications. The substrates formed by the higher levels of cattle manure plus biochar (30%) provided better results of height, diameter and aerial biomass. However, the Dickson Quality Index has not confirmed the quality of seedlings in these treatments. We also observed that the doses of biochar (20 and 30%) when added separately to the Latosol, are not efficient for the growth improvement of the seedlings. Based on the present results, we validate the hypothesis that substrates formed with a mixture of cattle manure and biochar are effective to improve the production of seedlings of M. pubescens.

Interactions between genes and alcohol on aggressive behavior and anger related traits : the oxytocin receptor gene as a candidate

Alkoholberusning är en av de starkaste riskfaktorerna för aggressivt beteende. Alla individer blir dock inte aggressiva under alkoholberusning. I sin doktorsavhandling undersökte Johansson ifall individens genetiska uppsättning kan förklara skillnader i vem som reagerar på alkohol med ökat aggressivt beteende och ilska och vem som inte gör det. Resultaten visade att individer som är bärare av en viss variant av genen som kodar för oxytocinets receptorer är i högre grad benägna att uppvisa aggressivt beteende än andra när de är alkoholberusade. Sambandet mellan alkohol och ilska påverkades även av individens genetiska uppsättning av två oxytocinreceptorgenvarianter, vilket antyder att dessa genvarianter även påverkar benägenheten att känna ilska under alkoholberusning. Oxytocinet, som fungerar både som ett hormon och en neurotransmittor, har i tidigare studier visats ha breda effekter på sociala förmågor hos människan, såsom förmåga till igenkännande av andras känslouttryck. Resultaten är de första att hos människan experimentellt påvisa att vissa individer beter sig mer aggressivt än andra när de är berusade, beroende på individens genetiska uppsättning. ”Det är viktigt att komma ihåg att genens effekt i det här fallet inte är av en sådan natur att den direkt och ofrånkomligen orsakar aggressivt beteende. Med andra ord är det orimligt i detta fall att tänka att en individ skulle tillmätas ansvarsfrihet i exempelvis ett våldsbrottmål om hon bär på en viss variant av denna gen”, påpekar Johansson. Oxytocinreceptorgenens effekter analyserades i två olika urval. I ett experimentellt upplägg indelades 116 män slumpässigt i två grupper: en grupp som tilldelades alkoholhaltiga drycker, och en kontrollgrupp som tilldelades alkoholfria drycker. Aggressivt beteende mättes med ett laboratorietest där försökspersonerna fick bestraffa en fiktiv motspelare genom att spela upp motbjudande ljud för denne. Resultaten replikerades i ett populationsbaserat urval av män och kvinnor (n = 3755) vilka besvarat frågor om deras aggressiva beteenden, ilska, och alkoholanvändning.

Effects of methylation and hydroxylation of sphingomyelins on their biophysical properties and interactions with cholesterol

Sfingomyeliner är viktiga sphingolipidmolekyler som finns i cellmembranets exoplastiska monolager. Sfingomyeliner är sällsynta i växter och mikroorganismer. Den enigmatiska sfingomelinmolekylen som Thudicum isolerade från hjärnvävnad i slutet på 1800-talet fick sitt namn på basen av det grekiska ordet”sfinx”. Sfingomyeliner återfinns speciallt rikligt i myelinskidorna i nervvävnad, var de sfingomyelinrika membranen bildar ett isolerande lager runt nervcellernas axoner. De polära sfingomyelinerna är viktiga beståndsdelar av ägg, mjölk och kött, och betraktas som viktiga näringsämnen speciellt för spädbarn. Det finns ett flertal sjukdomar uppstår på grund av defekter i sfingomyelinmetabolismen., t.ex. Niemann-Picks sjukdom, som är en obotlig ärftlig metabolisk sjukdom. Nyligen har det rapporterats att sfingomyelin tillsammans med kolesterol och specifika proteiner bildar funtionella domäner, s.k. membranflottar, i cellers membran. Membranflottar anses delta i många viktiga biologiska processer som t.ex. signalöverföring, lipid- och proteinsortering, apoptos, celladhesion, cellmigration och synapsers signalöverföring. Därför är det ytterst viktigt att förstå samverkan mellan sfingomyelin och kolesterol och hur denna samverkan påverkar bildandet membranflottar. I avhandlingen presenteras data från våra studier av sfingomyelin samverkan med kolesterol. För avhandlingen syntetiserade vi unika sfingomyelin molekyler genom att införa metyl- och hydroxylgrupper i olika positioner i sphingomyelinmolekylerna, med målet att lära oss mera om sphingomyelinets membranegenskaper och samverkan med kolesterol. Alla sfingomyelin molekyler som användes i avhandlingsarbetet är biologiskt relevanta. I studierna fann vi att hydroxyl- och amidgrupperna i sfingomyelin är viktiga i vätebindningar mellan sfingomyelinmolekyler samt mellan sfingomyelin och kolesterol. Vi upptäckte ytterligare att substition av metylgrupper i acylkedjan eller i interfasregionen hos sfingomyelinmolekyler signifikant destabiliserade sphingomyelin bilagret och försvagade/upphävde molekylernas samverkan med kolesterol. Hur sfingomyelinbilagrens stabilitet och sfingomyelinen-koleterol samverkan påverkades av hydroxylgrupper var beroende av hydrohygruppens position. Förekomst av en extra hydroxylgrupp i sfingomyelionmolekylens sfingoidbasen ökade stabilitetnen hos sfingomyelinbilagren samt stabiliserade sfingomyelinets samverkan med kolesterol.