La presente tesis doctoral titulada "Sondas moleculares y complejos de rutenio (II) y osmio (II) para la detección cromo-fluorogénica de especies cargadas y monóxido de carbono" se centra en el desarrollo de sensores químicos moleculares. El trabajo realizado se puede dividir en dos partes: (i) síntesis y caracterización de sondas moleculares multifuncionales para la detección óptica de aniones y cationes metálicos y, (ii) preparación de complejos de rutenio (II) y osmio (II) para la detección cromo-fluorogénica de monóxido de carbono. La primera familia de sondas moleculares, a la cual se hace referencia en el capítulo 2, se basa en el uso de imidazoantraquinonas como subunidad indicadora. Empleando este fragmento molecular se prepararon y caracterizaron cuatro sondas (2a-2d). De todos los aniones que se ensayaron, sólo el fluoruro es capaz de inducir la aparición de una banda de absorción (lo cual se refleja en diferentes cambios de color) y bandas de emisión desplazadas hacia el rojo. Estos cambios se atribuyen a la desprotonación del grupo N-H del anillo de imidazol inducida por el fluoruro. También los cationes Fe3+, Al3+ y Cr3+ son capaces de producir desplazamientos moderados hacia el azul de las bandas de absorción de los cuatro receptores, así como una desactivación marcada de la emisión a causa de su coordinación (con los átomos de oxígeno y nitrógeno del cromóforo imidazoantraquinona). El segundo capítulo también está dedicado al estudio del comportamiento de coordinación frente a aniones y cationes de una segunda familia de sondas (3a-3d) basadas en derivados de imidazoquinolina. Nuevamente el anión fluoruro promueve la desprotonación de estos compuestos, lo cual se refleja en la aparición de bandas de absorción y de emisión desplazadas hacia el rojo. En cuanto a la respuesta óptica en presencia de cationes metálicos es muy poco selectiva, observándose cambios en las bandas UV-visible y una desactivación de las bandas de emisión en presencia de Hg2+, Cu2+, Co2+, Fe3+, Fe2+, Zn2+, Pb2+, Cd2+, Cr3+ y Al3+. A lo largo del capítulo 3 se presenta la síntesis, caracterización y comportamiento cromo-fluorogénico frente al monóxido de carbono de dos conjuntos de complejos de rutenio (II) y osmio (II) que tienen en su esfera de coordinación los fluróforos 2,1,3-benzotiadiazol (BTD) y 5-(3-tienil)-2,1,3-benzotiadiazol (TBTD). En la primera parte de este capítulo se prepararon ocho compuestos con el ligando BTD (1-8). Al burburjearles CO, las disoluciones de cloroformo de dichos complejos mostraron notables cambios de color. Además, su emisión se vio incrementada debido a la coordinación de los complejos con el CO y el desplazamiento del fluoróforo BTD. Por otro lado, la adsorción de los complejos en sílice dio lugar a sólidos que presentaron importantes cambios de color permitiendo la detección de CO en fase gas a simple vista y con alta selectividad y sensitividad. El segundo conjunto de complejos de rutenio (II) y osmio (II) contiene el fluróforo TBTD (3-7). Éstos también son capaces de detectar CO cuando se encuentran disueltos en cloroformo y adsorbidos en sílice a través de cambios de color y fluorescencia. Por otra parte, se prepararon dos nuevos complejos (8 y 9) funcionalizados con una cadena de polietilenglicol. Ambos complejos son solubles en agua y permiten la detección de CO en este disolvente altamente competitivo. Además, los compuestos 8 y 9 no son tóxicos y se emplearon con éxito en la detección de CO en células HeLa. / The present PhD thesis entitled "Molecular probes and ruthenium (II) and osmium (II) complexes for the chromo-fluorogenic sensing of charged species and carbon monoxide" is focused on the development of molecular chemosensors. More in detail, the work carried out is clearly divided into two independent parts: (i) the synthesis and characterization of multifunctional molecular probes for the optical detection of anions and metal cations and, (ii) the preparation of ruthenium (II) and osmium (II) complexes for the chromo-fluorogenic sensing of carbon monoxide. The first family of molecular probes, reported in chapter 2, is based on the use of imidazoanthraquinone as signaling subunit. Using this molecular fragment four probes (2a-2d) are prepared and characterized. Of all the anions tested, only fluoride is able to induce the appearance of red-shifted absorption (reflected in marked color changes) and emission bands. These changes are ascribed to a fluoride-induced deprotonation of the N-H moiety of the imidazole ring. Also Fe3+, Al3+ and Cr3+ were able to induce moderate blue-shifts of the absorption bands of the four receptors upon coordination (with the oxygen and nitrogen atoms of the imidazoanthraquinone chromophore) and marked emission quenching. The second chapter is also devoted to study the coordination behavior toward anions and cations of a second family of probes (3a-3d) containing imidazoquinoline derivatives. Again, fluoride anion promoted the deprotonation on the probes that are reflected in the apperacence of red-shifted absorption and emission bands. The optical response in the presence of metal cations is quite unselective and UV-visible shifts and emission quenchings are observed in the presence of Hg2+, Cu2+, Co2+, Fe3+, Fe2+, Zn2+, Pb2+, Cd2+, Cr3+ and Al3+. Chapter 3 presents the synthesis, characterization and chromo-fluorogenic behavior toward of carbon monoxide of two set of ruthenium (II) and osmium (II) complexes bearing 2,1,3-benzothiadiazole (BTD) and 5-(3-thienyl)-2,1,3-benzothiadiazole (TBTD) fluorophores. Eight complexes functionalized with BTD ligand (1-8) are prepared in the first part of this chapter. Chloroform solutions of the complexes underwent remarkable color changes when CO is bubbled. Also, significative emission enhancements are obserbed due to coordination of CO and displacement of BTD fluorophore. Besides, the adsorption of the complexes on silica yielded solids that presented remarkable color changes that allowed a naked eye detection of CO in gas phase. The second set of ruthenium (II) and osmium (II) complexes contains TBTD fluorophore (3-7). Also these complexes are able to detect CO in chloroform solution and in gas phase when adsorbed on silica through color and fluorescence changes. Moreover, two new complexes (8 and 9) containing a poly(ethylene) glycol chain are prepared. Both complexes are water soluble and allowed CO detection in this highly competitive solvent. Besides, 8 and 9 are non-toxic and are successfully used for CO detection in HeLa cells. / La present tesi doctoral titulada "Sondas moleculars i complexos de ruteni (II) i osmi (II) per a la detecció cromo-fluorogènica d'espècies carregades i monòxid de carboni" es centra en el desenvolupament de sensors químics moleculars. El treball realizat es pot dividir en dues parts: (i) síntesi i caracterització de sondes moleculars multifuncionals per a la detecció òptica d'anions i cations metàli·lics i, (ii) preparació de complexos de ruteni (II) i osmi (II) per a la detecció cromo-fluorogènica de monòxid de carboni. La primera família de sondes moleculars, a la qual es fa referència en el capítol 2, es basa en l'ús d'imidazoantraquinones com a subunitat indicadora. Emprant aquest fragment molecular es van preparar i caracteritzar quatre sondes (2a-2d). De tots els anions que es van assajar, només el fluorur és capaç d'induir l'aparició d'una banda d'absorció (la qual cosa es reflecteix en diferents canvis de color) i bandes d'emissió desplaçades cap al roig. Aquestos canvis s'atribuïxen a la desprotonació del grup NH de l'anell d'imidazol induïda pel fluorur. També els cations Fe3+, Al3+ i Cr3+ són capaços de produir desplaçaments moderats cap al blau de les bandes d'adsorció dels quatre receptors, així com una desactivació marcada de l'emissió a causa de la seua coordinació (amb els àtoms d'oxigen i nitrogen del cromòfor imidazoantraquinona). El segon capítol també està dedicat a l'estudi del comportament de coordinació en presència d'anions i cations d'una segona família de sondes (3a-3d) basades en derivats d'imidazoquinolina. Novament l'anió fluorur promou la desprotonació d'aquestos compostos, la qual cosa es reflecteix en l'aparició de bandes d'absorció i d'emissió desplaçades cap al roig. Quant a la resposta òptica en presència de cations metàl·lics és molt poc selectiva, observant-se canvis en les bandes UV-visible i una desactivació de les bandes d'emissió en presència de Hg2+, Cu2+, Co2+, Fe3+, Fe2+, Zn2+, Pb2+, Cd2+, Cr3+ i Al3+. Al capítol 3 es presenta la síntesi, caracterització i comportament cromo-fluorogènic en presència de monòxid de carboni de dos conjunts de complexos de ruteni (II) i osmi (II) que tenen a la seua esfera de coordinació els fluoròfors 2,1,3-benzotiadiazol (BTD) i 5-(3-tienil)-1,2,3-benzotiadiazol (TBTD). A la primera part d'aquest capítol es van preparar huit compostos amb el lligant BTD (1-8). Al bambollejar-les CO, les dissolucions de cloroform d'aquestos complexos van mostrar notables canvis de color. A més, la seua emissió es va veure incrementada a causa de la coordinació dels complexos amb el CO i el desplaçament del fluoròfor BTD. D'altra banda, l'adsorció dels complexos en sílice va donar lloc a sòlids que van presentar importants canvis de color premetent la detecció de CO en fase gas a simple vista i amb alta selectivitat i sensitivitat. El segon conjunt de complexos de ruteni (II) i osmi (II) conté el fluoròfor TBTD (3-7). Aquestos també són capaços de detectar CO quan es troben dissolts en cloroform i adsorbits en sílice a través de canvis de color i fluorescència. D'altra banda, es van preparar dos nous complexos (8 i 9) funcionalitzats amb una cadena de polietilenglicol. Ambdós complexos són solubles en aigua i permeten la detecció de CO en aquest dissolvent altament competitiu. A més, els compostos 8 i 9 no són tòxics i es van emprar amb èxit en la detecció de CO en cèl·lules HeLa. / Marín Hernández, C. (2017). Molecular probes and ruthenium (II) and osmium(II) complexes for the chromofluorogenic sensing of charged species and carbon monoxide [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/95407 / TESIS

Characterization of potassium cation transport systems in the yeast Zygosaccharomyces rouxii Potassium has become absolutely necessary cation for living cells, including yeasts, because it plays several important roles in physiological processes. Intracellular concentration of K+ in yeasts is usually between 200 mM and 300 mM, while the external K+ concentration is ranging from molar to micromolar. To adapt to environments with low K+ content, yeast cells employ various K+ high-affinity uptake systems, e.g. Trk, Hak and K+ -ATPase, that provide cells with the sufficient amount of potassium. The recent release of the complete sequence of the osmotolerant yeast Zygosaccharomyces rouxii genome allowed us to search homologues of the known yeast potassium uptake systems. We have found just one gene encoding a putative potassium transporter homologous to the S. cerevisie TRK1. For the characterisation of transport properties and physiological roles of the product of this gene, named ZrTRK1, three approaches have been used. First, the IT tools serve to analyse sequence characteristics, phylogenetic relationships etc. The second approach involves cloning of the gene and its expression in a S. cerevisiae mutant strain lacking its own two Trk systems, characterisation of transformants' growth phenotypes and...

The MAO-B catalyzed metabolic bioactivation of the parkinsonian inducing agent 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to generate the neurotoxic 1-methyl-4-phenylpyridinium species (MPP+) is well documented. The N-cyclopropyl analog (CPTP) of MPTP is a mechanism based inactivator of MAO-B which presumably is processed by a single electron transfer (SET) pathway to generate a bioalkylating species. These results have prompted us to study how the cytochromes P450, the major liver drug metabolizing oxidases, interact with N-cyclopropyl analogs of MPTP. HPLC with diode array detection and LC-electrosprary ionization mass spectrometry (LC-ESI/MS) based methods have been developed for metabolite detection and characterization. From the UV spectral data and pseudomolecular ion species observed by LC-ESI/MS, we have identified N-oxide, C-hydroxylated, and pyridinium metabolites. For the trans-1-(2-phenylcyclopropyl) analog, cinnamaldehyde and p-hydroxycinnamaldehyde also were characterized. Incubation of CPTP and its derivatives with cDNA expressed human hepatic cytochrome P450 has shown that CYP2D6 catalyzes the formation of cinnamaldehyde, the N-descyclopropyl, pyridinium and hydroxylated products. CYP3A4 is responsible for the formation of the N-descyclopropyl and pyridinium species and cinnamaldehyde but it does not mediate any hydroxylation reactions. Since both the a-carbon oxidation and N-descyclopropylation transformations are mediated by a single enzyme (either CYP2D6 or CYP3A4), we propose a common intermediate for both pathways, namely the cyclopropylaminyl radical cation generated by the SET pathway. This intermediate partitions between the a-carbon oxidation pathway leading to the dihydropyridinium and pyridinium species and the ring opening pathway leading to the N-descyclopropyl metabolite and aldehyde species. The phenyl substituent on the cyclopropyl ring stabilizes the ring opened distonic radical cation and favors the ring opening pathway and results in the formation of less of the pyridinium species. The proton and methyl substituents on the cyclopropyl ring favor the a-carbon oxidation pathway and increased amounts of the pyridinium species are formed. / Master of Science

Compartmentalization allows for the spatial organization of cellular components and is crucial for numerous biological functions. One recently uncovered strategy for intracellular compartmentalization is phase separation via the de-mixing of biomacromolecules. Membraneless organelles, also referred to as biomolecular condensates, are compartments formed by phase separation and create distinct environments that are essential to cellular processes ranging from cell signaling to gene expression. Biomolecular condensates offer several advantages – for example, dynamic restructuring of internal constituents and diffusion of cellular components into/out of compartments – that make them suitable for applications in biocatalysis or pharmaceutical production. However, the ability to independently engineer the formation and disassembly of condensates in vivo remains a challenge. Here, concepts from polymer science have been used to understand parameters that govern intracellular phase separation. Many biomolecular condensates exhibit physical properties that are similar to complex coacervates as both are liquid-like phase separated mixtures formed via associative phase separation, frequently with oppositely charged polyelectrolytes. We utilize the physical phenomenon of complex coacervation and principles underlying the formation of liquid-like biological condensates to identify design parameters for engineering synthetic, phase separated organelles in E. coli. In this dissertation, we employed a library of cationic charge variants derived from superfolder green fluorescent protein (sfGFP) to elucidate the effects of overall cationic charge on intracellular phase separation. We first investigated the complex coacervation of engineered proteins with biological polyelectrolytes to determine predictive design rules for protein phase separation and translated these design rules in vivo to engineer bacterial condensates. Characterization of the coacervate-like properties and macromolecular composition revealed that these condensates can undergo dynamic restructuring and exhibit biomolecular specificity. To facilitate the engineering of active supercharged proteins, we also developed short, cationic peptide tags, ranging from 6-27 amino acids in length, that can be appended onto any protein of interest to promote intracellular phase separation. We find that overall charge generally determines protein phase behavior and observe the formation and disassembly of condensates near the physiological phase boundary. Interestingly, we find that small modifications in charge density can tune the interaction strength between associating biomacromolecules and thus tune condensate stability. We demonstrate the use of these protein design parameters and cationic peptide tags to sequester catalytic enzymes and manipulate the intracellular localization of multiple proteins. These studies pave the way to building synthetic, functional organelles.

In this work, the evolutionary biophysics approach is applied to the two of the largest protein superfamilies present in human genomes, namely P-loop fold nucleoside triphosphatases (P-loop NTPases) and G-protein coupled receptors (GPCRs). This approach combines comparative analysis of protein structures and sequences with molecular modeling techniques in order to reveal not only the conservation of particular residues among proteins within each superfamily but also their role in the fundamental mechanisms underlying common functions. The study of the hydrolysis activation mechanism in P-loop NTPases started with the molecular dynamics simulations of Mg-NTP complexes (Mg-ATP and Mg-GTP) in the presence of K+, NH4+, and Na+ ions. These simulations showed that in the presence of large cations (K+ and NH4+), the conformation of the phosphate chain of ATP and GTP is extended, with large distances between alpha- and gamma-phosphates. This conformation is similar to the shape of ATP and GTP molecules (or their analogs) in the crystal structures of various P-loop NTPases. To clarify the role of monovalent cations in P-loop NTPases, MD simulations were conducted for two cation-dependent GTPases: tRNA modification GTPase MnmE and translation factor EF-Tu. MD simulations of Mg-GTP/EF-Tu complex bound to the tRNA and ribosome fragment in the presence of K+ ions have shown consistent binding of a potassium ion from the solution between alpha- and gamma-phosphates (AG site), similar to the cation binding in MnmE and other cation-dependent P-loop GTPases. In both proteins, binding of K+ ion in the AG site led to the rotation of gamma-phosphate, making this group more eclipsed with alpha-phosphate. The new rotated position of gamma-phosphate was stabilized by a novel H-bond with the backbone nitrogen of the K-3 residue (relative to the ubiquitously conserved Lys) of the P-loop motif. The activation mechanism observed in MD simulations of MnmE and EF-Tu could be envisioned as basic for P-loop NTPases, as these cation-dependent proteins are among the most ancient members of the P-loop superfamily. This mechanism was used as a basis for extensive comparative analysis of representative proteins from all major classes of P-loop NTPases. Based on the established conservation and presence of the key features in active sites of P-loop NTPases, the chain of events where rotation of gamma-phosphate triggers the nucleophilic attack and gamma-phosphate cleavage has been proposed as the basic universal activation mechanism of NTP hydrolysis in P-loop NTPases. The second part of this work explores the activation of GPCRs as sodium-translocating receptors. Crystal structures of the novel Na-pumping microbial rhodopsin along with the recent avalanche of GPCR structures provided the basis for comparative structure analysis, focused on investigating the similarities in the Na-binding sites of the two superfamilies. Structure superposition of GPCRs and microbial rhodopsins (MRs) based on comparison of their Na-binding sites was used to produce structure-guided sequence alignments of the two superfamilies. The only residue universally conserved between the two superfamilies was Trp in the helix 6/F (Trp6.48 in GPCRs). In both families, the signaling mechanism directly involves this residue, which is likely to be an ancient feature inherited from the common ancestor of MRs and GPCRs – the Na-pumping light-activated rhodopsin. The similarity of GPCRs with light-activated sodium pumps endorses the suggestion that GPCRs may also function as Na+ ion translocators. A model of GPCR activation accompanied by translocation of Na+ was constructed to demonstrate how this mechanism can explain the voltage sensitivity of certain Class A GPCRs. Two modes of activation were modeled – one where Na+ ion is transported into the cytoplasm and the one where Na+ ion is expelled to the intracellular space. The two modes quantitatively describe the behavior of voltage-activated and voltage-suppressed GPCRs, respectively. Finally, further structure scrutiny and rotamer analysis provided a plausible pathway of Na+ transmembrane translocation through the helical bundle of GPCRs.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19407号 / 工博第4123号 / 新制||工||1636(附属図書館) / 32432 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 吉田 潤一, 教授 松田 建児, 教授 松原 誠二郎 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p>      Chemical reactions in micron-sized droplets under ambient conditions are often orders of magnitude faster than the equivalent bulk reactions due to the large interfacial effects. The investigation of the underlying mechanisms driving the unique surface chemistry of droplets, as well as their applications and implications in synthesis, has garnered considerable interest. This dissertation delves into three key subtopics: (1) Exploring partial solvation as a mechanism for accelerating reactions in microdroplets, (2) Investigating the spontaneous oxidation and reduction of heteroatom double bonds induced by water radical cations and anions generated from water, and (3) Examining the role of oxazolone intermediates in prebiotic peptide synthesis and the emergence of homochirality in living systems.</p> <p>      Chemical reactions can be accelerated in microdroplets but with previously unclear mechanisms. Here we report a systematic study of organic reactions of common types in microvolumes and compare their rates with those in bulk solution. The observed interfacial area effect, molecularity effect and solvent effect provided experimental evidence for partial solvation at gas/liquid interface as one of the major contributors to the observed more than 10⁴-fold acceleration in microdroplets.</p> <p>      Recent spectroscopic results as well as computations demonstrate the existence of a strong electric field at aqueous droplet surfaces, which can result in microdroplet-specific reactions, especially their intrinsic redox properties. Spontaneous oxidation or reduction without external oxidants or reductants has been reported. One explanation for the existence of active species is dissociation of the radical cation/anion pair (H₂O^+∙/ H₂O^-∙), recently argued to occur in pure bulk water, to provide the free radical cation and radical anion. In this work, we reported spontaneous oxidation of heteroatom double bonds (e.g. sulfone to sulfonic acid, ketone to carboxylic acid) in non-aqueous microdroplets containing traces of water (<1%). Meanwhile, the simultaneous oxidation and reduction of several phosphonates was discovered, supporting the radical pair as the source of reactive species in water microdroplets.</p> <p>      One implication of microdroplet chemistry lies in its connection to prebiotic synthesis. Peptide formation from amino acids is thermodynamically unfavorable but a recent study provided evidence that the reaction occurs at the air/solution interfaces of aqueous microdroplets. Here we show that (i) the suggested amino acid complex in microdroplets undergoes dehydration to form oxazolone; (ii) addition of water to the oxazolone forms the dipeptide; and (iii) reaction of oxazolone with other amino acids forms tripeptides. Furthermore, the chirality of the reacting amino acids is preserved in the oxazolone, and strong chiral selectivity is observed when converting the oxazolone to tripeptide. This last fact ensures that optically impure amino acids will undergo chain extension to generate homochiral peptides. Peptide formation in bulk by wet-dry cycling shares a common pathway with the microdroplet reaction, both involving the oxazolone intermediate.</p>

yes / The density functional theory (DFT) based a unique model has been developed to predict the toxicity of ionic liquids using structural-feature based quantum chemical reactivity descriptors. Electrophilic indices (ω), the energy of highest occupied (EHOMO) and lowest unoccupied molecular orbital, (ELUMO) and energy gap (∆ E) were selected as the best toxicity descriptors of ILs via Pearson correlation and multiple linear regression analyses. The principle components analysis (PCA) demonstrated the distribution and inter-relation of descriptors of the model. A multiple linear regression (MLR) analysis on selected descriptors derived the model equation for toxicity prediction of ionic liquids. The model predicted toxicity values and mechanism are very consistent with observed toxicity. Cationic and side chains length effect are pronounced to the toxicity of ILs. The model will provide an economic screening method to predict the toxicity of a wide range of ionic liquids and their toxicity mechanism.

Svensk Kärnbränslehantering AB beslutade 2009 att bygga ett slutförvar av använt kärnbränsle i anslutning till kärnkraftverket i Forsmark. Tekniken för slutförvaret går ut på att omge kapslarna med bentonitlera som skydd mot vatten och bergsrörelser. Studier har dock påpekat att bentonitleran riskerar att kemiskt erodera om jonstyrkan (baskatjonerna) i grundvattnet som omsluter förvaringen blir för låg. Baskatjoner består av natrium, kalium, kalcium och magnesium. Dessa joner är viktiga för bland annat att neutralisera syror i mark och vatten. Förekomsten av dessa har sedan 90-talet minskat men kan påverkas av både ökad nederbördsmängd och ökad temperatur i vissa regioner. Baskatjoner kan lakas ur marken när pH minskar eller komma via deposition från nederbörden. Studien syftar till att utreda vilka faktorer som påverkar dels förekomsten av baskatjoner, dels dess trender i tre olika vattentyper i Forsmark: grunt grundvatten, sjövatten och vattendrag. Dataunderlaget för baskatjonerna kom från Svensk Kärnbränslehantering AB och nederbördsmängd och temperatur från Sveriges Meteorologiska och Hydrologiska Institut. De statistiska testerna som utfördes var främst Wilcoxon rank-sum test, Spearmans rangkorrelation, Mann-Kendalls trend- test och Sen’s slope-metoden. Analyserna har utförts med statistikprogramvaran R och de geografiska med QGIS. Resultatet visade att flera provtagningspunkter låg på en låg altitud och inom samma delavrinningsområde. Det fanns små skillnader i baskatjonskoncentrationen i de tre vattentyperna oberoende av berggrund, jordart eller terräng. Dock återfanns högst koncentration i de flesta fall i grunt grundvatten vilket kunde bero på höga halter natrium från havsvattnet samt kalksten i jordlagren. Korrelationerna var få varav sulfat var den som tydligast visade på ett förhållande med baskatjonerna i alla tre vattentyperna. Inte heller kunde en samvariation med temperatur och nederbörd statistiskt säkerställas. Trenderna visade på minskande koncentration av baskatjoner i grunt grundvatten och i sjövatten. Om dessa trender fortsätter utifrån studiens resultat kan det på sikt finnas en risk för erodering av bentonitleran runt kapslarna till följd av landhöjning och utbyte av det nuvarande bräckta grundvattnet. / The Swedish Nuclear Fuel and Waste Management Company decided in 2009 to build a final repository for spent nuclear fuel in connection with the nuclear power plant in Forsmark. The technology for the final repository involves surrounding the capsules with bentonite clay as protection against water and rock movements. However, studies have pointed out that the bentonite clay is at risk of chemically eroding if the ionic strength of the groundwater surrounding the repository becomes too low. Base cations consist of sodium, potassium, calcium, and magnesium. These ions are important for neutralizing acids in soil and water. The occurrence of these has decreased since the 90s but can be affected by both increased rainfall and increased temperature in certain regions. Base cations can further be leached from the soil when the pH decreases or come via deposition from precipitation. This study aims to investigate which factors affect the presence of base cations and their trends in three different types of water in Forsmark: shallow groundwater, lake water and stream water. The data set for the base cations came from the Swedish Nuclear Fuel and Waste Management Company and rainfall and temperature from the Swedish Meteorological and Hydrological Institute. The statistical tests performed were mainly the Wilcoxon rank-sum test, Spearman's rank correlation, Mann-Kendall's trend test and Sen's slope method. The analyzes have been performed with the statistical software R and the geographic ones with QGIS. The result showed that several sampling points were at a low altitude and within the same sub-catchment. There were small differences in base cation concentration in the three water types regardless of bedrock, soil type or terrain. However, the highest concentration was found in most cases in shallow groundwater, which could be due to high levels of sodium from seawater and limestone in the soil layers. The correlations were few, of which sulfate was the one that most clearly showed a relationship with the base cations in all three water types. Nor could a co-variation with temperature and precipitation be statistically ensured. The trends showed a decreasing concentration of base cations in shallow groundwater and in lake water. If the trends continue based on the results, in the long term there may be a risk of erosion of the bentonite clay that surrounds the capsules because of land uplift and replacement of the current brackish ground water.

A laboratory test program was conducted to investigate the effects of temperature, solution strength, and applied stress over increasing conditioning durations on cation exchange processes in sodium bentonite (Na-B) geosynthetic clay liners (GCLs). The test program was intended to determine if the variables of temperature, solution strength, and applied stress had beneficial or detrimental effects on the engineering behavior of Na-B GCLs in municipal solid waste (MSW) landfills and laboratory testing applications. Needlepunched-reinforced, double non-woven Na-B GCL specimens were conditioned in fluids of increasing ionic strength (DI water, 2 mM CaCl2, 50 mM CaCl2, and 200 mM CaCl2 representing control, pore water, mild MSW leachate, and harsh MSW leachate, respectively), temperatures of 5 degrees C, 20 degrees C, 40 degrees C, and 60 degrees C, and overburden stresses (30 kPa and 500 kPa representing stresses experienced by cover and bottom liner systems, respectively) which are all representative of geoenvironmental conditions observed in MSW landfill barrier systems. Cation exchange in the bentonite component of all conditioned Na-B GCL specimens was quantified by measuring the bound cation (BC) complexes and cation exchange capacities (CEC) of the specimens using inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and by conducting index tests to determine the dimensional characteristics, swell index, and gravimetric moisture content of the specimens. For zero stress conditions, periodic measurements of electrical conductivity, total dissolved solids, sodium and calcium cation concentration, and temperature of the conditioning fluids were recorded to supplement bound cation complex data. For applied stress conditions, electrical conductivity, total dissolved solids, and temperature of the conditioning fluid were recorded. For zero stress conditions, 152 mm x 152 mm Na-B GCL specimens were conditioned in all conditioning fluids and temperatures over increasing time durations ranging from 4 hours to 32 days. For applied stress conditions, 60-mm-diameter Na-B GCL specimens were conditioned in 50 mM CaCl2 conditioning fluid at all temperatures for 4 to 16 days under the applied overburden stresses of 30 kPa and 500 kPa. Temperature, solution strength, and applied stress were all observed to affect cation exchange in the bentonite component of Na-B GCLs. Cation exchange processes were observed to increase with increasing temperature, increasing solution strength, and decreasing applied overburden stress. The majority of cation exchange processes were observed to occur within 8 to 10 days for specimens conditioned under zero stress. Cation exchange processes were observed to have a higher sensitivity to changes in solution strength (up to 625% increase in the change of Na+ BC from DI water to 200 mM CaCl2) compared to changes in temperature (up to 52% increase in the change of Na+ BC from 5 degrees C to 60 degrees C) in zero stress conditions. Changes in the bound cations of the Na-B GCL specimens over time were not reflected in the periodic electrical conductivity measurements taken of the high strength conditioning fluids. The results of this study can be used for quality assurance evaluations of in-service GCLs using thresholds developed for index properties. From the numerical thresholds determined in this study, hydrated Na-B GCL specimens sampled from the field conditioned under zero stress that exhibit swell indices greater than or equal to approximately 70% of the swell index reported by the manufacturer and gravimetric moisture contents of greater than or equal to approximately 200% will likely exhibit adequate hydraulic barrier performance. Hydrated Na-B GCL specimens sampled from the field conditioned under zero stress that exhibit swell indices of less than or equal to approximately 20% of the swell index reported by the manufacturer and gravimetric moisture contents of less than or equal to approximately 100% will likely exhibit inadequate hydraulic barrier performance. The Na-B GCL component of cover liner systems may be susceptible to high rates of cation exchange due to experiencing low overburden stress and elevated temperatures compared to typical earth temperatures. The Na-B GCL component of bottom liner systems may exhibit low rates of cation exchange due to experiencing high overburden stress and cooler temperatures.