In this thesis the pH dependency of the coordination modes of lanthanide complexes with macrocyclic ligands based on 1,4,7,10-tetraazacyclododecane skeleton was studied. The cyclen-based ligand structures in this work contained three acetate and one aminoethyl group with a N-alkyl-N-methylphosphonate substituent, DO3AN(R)P, where R is an alkyle substituent on the nitrogen atom of the pendant arm (R = methyl, benzyl). Lanthanide complexes of a previously studied prototype ligand DO3ANP with secondary amino group (R = H) have shown interesting properties in the field of 31 P NMR imaging because of their various coordination properties, which allow in situ pH measurement. These complexes can also be used for monitoring the kinetics of the chemical exchange of the amino group proton in 1 H NMR imaging using the chemical exchange saturation transfer (CEST NMR). In this thesis, two new derivatives DO3ANMeP and DO3ANBnP were prepared in order to better understand the coordination modes changes in this ligand series. Also, their coordination behaviour with selected lanthanide ions was studied (Eu3+ , Gd3+ , Dy3+ , Yb3+ ). Based on a series of NMR and luminescence measurements, it was found out, that in acidic conditions the complexes containing DO3ANP motif bind a water molecule in their coordination...

Les dilatations des voies urinaires de diagnostic anténatal (DVU) peuvent être transitoires, ou correspondre à une anomalie significative de l'écoulement des urines pouvant entrainer une dégradation de la fonction rénale. L'identification de biomarqueurs urinaires pourrait contribuer à différencier précocement les uropathies des dilatations transitoires. La métabolomique permet l'identification de toutes les molécules de bas poids moléculaire présentes dans un échantillon biologique et la mise en évidence d'une signature métabolique associée à un événement physiopathologique. L'objectif principal de cette thèse est l'identification de marqueurs urinaires pronostiques chez les nouveaux nés présentant une DVU de diagnostic anténatal, par spectroscopie RMN et analyse métabolomique.Soixante-dix nouveau-nés ayant une DVU unilatérale et 90 témoins ont été inclus dans cette étude prospective. Tout d'abord, nous comparons la précision de différentes classifications échographiques pour l'évaluation du risque d'intervention chirurgicale.Ensuite, nous montrons l'absence de différence significative entre les profils métaboliques urinaires des nouveau-nés ayant une DVU et ceux des témoins. Dans une troisième partie, nous démontrons l'influence significative de l'âge, du poids et de la taille sur le profil métabolique urinaire des nouveau-nés. Enfin, nous montrons l'évolution du profil métabolique urinaire avec la croissance chez les nourrissons ayant une DVU.Ce travail permet une meilleure compréhension de la physiopathologie des DVU et de la maturation métabolique des nouveau-nés. Il contribue à identifier des biais potentiels dans les études métaboliques en néonatologie / The prenatal finding of unilateral Urinary Tract Dilatation (UTD) can be transient or represent a significant urinary flow impairment that would lead to progressive deterioration of renal function. Identifying urinary biomarkers could help to differentiate uropathy requiring surgical management from transient dilatation at an early stage.Metabolic phenotyping studies provide untargeted quantification of all detectable low molecular-weight molecules by profiling without any a priori the metabolic signatures of biological samples in connection to physiopathological events.The main objective of this study is to identify diagnosis and prognosis urinary markers for uropathy in newborns with prenatally diagnosed unilateral UTD using 1H-NMR spectroscopy combined with multivariate statistical analyses.A total of 70 newborns with unilateral UTD and 90 controls were included in this prospective study. First, the usefulness of different ultrasound grading systems in predicting the need for surgical intervention is evaluated. Then, we report the absence of significant difference between the urinary metabolic profiles of newborns with UTD and controls. In thethird part, the influence of age, weight and height on the urinary metabolic profiles of healthy newborns is highlighted for the first time, and key-metabolites responsible for this evolution are identified. Finally, we demonstrate the influence of age on the urinary metabolic profiles of children with UTD. This work allows a deeper understanding of the metabolic maturation of healthy newborns. It contributes to identify potential confounding factors for metabolomics investigations in neonatology. It represents a step toward a better comprehension of thephysiopathology of UTD

No description available.

No / We describe the Δlog P method for the assessment of intramolecular hydrogen bonds (IMHBs), and show that it is not a very general method of distinguishing between molecules in which there is an IMHB and molecules in which there is no IMHB. The ‘double’ Δlog P method of Shalaeva et al. is a much more reliable method for the assessment of IMHB but requires the synthesis of a model compound and the determination of no less than four water-solvent partition coefficients. In addition, it is difficult to apply to compounds that contain more than one hydrogen bond acidic group capable of IMHB. We then describe our NMR method of assessing IMHB, based on 1H NMR chemical shifts in solvents DMSO and CDCl3. We have determined 1H NMR chemical shifts for a number of ortho-substituted anilines and show that the only compound we have studied that forms an IMHB is methyl 2-methylaminobenzoate though there is no IMHB present in methyl 2-aminobenzoate. This apparently anomalous result is supported by both MM and ab initio calculations. The NMR method is much simpler and less time consuming than other methods for the assessment of IMHB. It provides a quantitative assessment of IMHB and can be applied to molecules with more than one hydrogen bond acidic group.

Age and sex are risk factors of Alzheimer's disease (AD). Among the neurotransmitter systems, gamma-aminobutyric acid (GABA) has been implicated in AD pathogenesis but the relevance of sex-specific GABAergic dysfunction during AD progression remains unknown. In the present study, we utilized state-of-the-art high-resolution magic angle spinning nuclear magnetic resonance to systematically monitor the brain region-, age-, and sex-specific modulation of GABA levels in wild-type and Tg2576 mice with amyloid pathology. In addition, we followed the possible role of reactive astrocytes in sex-specific GABA modulation. In female Tg2576 mice, hippocampal GABA levels were significantly elevated, along with higher number of reactive astrocytes and amyloid deposition. The elevated GABA was found to be produced via the monoamine oxidase-B route from putrescine in reactive astrocytes, more substantially in female than male mice, thus suggesting a role of astrocytes in memory impairment and sex-related differences in AD. Our results paint a coherent model of memory impairment in AD and signify that dynamic changes in regional GABA may be at the root of marked sex disparities observed in AD.

Yes / We describe the Δlog P method for the assessment of intramolecular hydrogen bonds (IMHBs), and show that it is not a very general method of distinguishing between molecules in which there is an IMHB and molecules in which there is no IMHB. The ‘double’ Δlog P method of Shalaeva et al. is a much more reliable method for the assessment of IMHB but requires the synthesis of a model compound and the determination of no less than four water-solvent partition coefficients. In addition, it is difficult to apply to compounds that contain more than one hydrogen bond acidic group capable of IMHB. We then describe our NMR method of assessing IMHB, based on 1H NMR chemical shifts in solvents DMSO and CDCl3. We have determined 1H NMR chemical shifts for a number of ortho-substituted anilines and show that the only compound we have studied that forms an IMHB is methyl 2-methylaminobenzoate though there is no IMHB present in methyl 2-aminobenzoate. This apparently anomalous result is supported by both MM and ab initio calculations. The NMR method is much simpler and less time consuming than other methods for the assessment of IMHB. It provides a quantitative assessment of IMHB and can be applied to molecules with more than one hydrogen bond acidic group.

Since the development of the ruthenium containing precatalysts Grubbs 1 (1) and Grubbs 2 (2), there was an increase in the development of new precatalysts. The NMR characterization could not cope with this. The NMR characterization mainly consists of 1H, 31P, COSY and rarely 13C. Due to the high natural abundance of 1H and 31P (99.98% and 100%), these experiments could be carried out quickly and easily. The only change that had to be made was to the spectral width, to accommodate the carbene signal (Ru=CH) between δ 20.02 and δ 17.32 ppm. The lack of 13C characterization is attributed to the low natural abundance of these nuclei that is only 1.10% and the lack of published parameters. Furthermore, the broad spectral width of 300 ppm increases the difficulty because the number of scans has to be increased to increase the sensitivity of the spectra and obtain useful data. In this study the precatalyst 1 was used to learn the NMR technique as well as to acquire the NMR parameters. 2 and two other commercial Grubbs-type precatalysts 3 and 4 underwent NMR characterization so that acquired values could be compared with the literature. Six other non-commercial Grubbs-type precatalysts 5-10 were synthesized and characterized. Due to the instability of the precatalysts and taking into account the duration of these experiments, the characterization was done over three steps. The first step was to do the following experiments: 1H, COSY, HSQC and HMBC, which took four hours. The next step was the DEPT135 experiment of three hours, and finally the 13C experiment of seven hours. The maximum amount of information could be obtained in this way. The combined NMR parameters for this study was obtained and used to characterize the Grubbs-type precatalysts 5-10 partially. Due to the large amount of overlapping peaks in the aromatic and alkane areas the resolution was not sufficient for full characterization. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

Since the development of the ruthenium containing precatalysts Grubbs 1 (1) and Grubbs 2 (2), there was an increase in the development of new precatalysts. The NMR characterization could not cope with this. The NMR characterization mainly consists of 1H, 31P, COSY and rarely 13C. Due to the high natural abundance of 1H and 31P (99.98% and 100%), these experiments could be carried out quickly and easily. The only change that had to be made was to the spectral width, to accommodate the carbene signal (Ru=CH) between δ 20.02 and δ 17.32 ppm. The lack of 13C characterization is attributed to the low natural abundance of these nuclei that is only 1.10% and the lack of published parameters. Furthermore, the broad spectral width of 300 ppm increases the difficulty because the number of scans has to be increased to increase the sensitivity of the spectra and obtain useful data. In this study the precatalyst 1 was used to learn the NMR technique as well as to acquire the NMR parameters. 2 and two other commercial Grubbs-type precatalysts 3 and 4 underwent NMR characterization so that acquired values could be compared with the literature. Six other non-commercial Grubbs-type precatalysts 5-10 were synthesized and characterized. Due to the instability of the precatalysts and taking into account the duration of these experiments, the characterization was done over three steps. The first step was to do the following experiments: 1H, COSY, HSQC and HMBC, which took four hours. The next step was the DEPT135 experiment of three hours, and finally the 13C experiment of seven hours. The maximum amount of information could be obtained in this way. The combined NMR parameters for this study was obtained and used to characterize the Grubbs-type precatalysts 5-10 partially. Due to the large amount of overlapping peaks in the aromatic and alkane areas the resolution was not sufficient for full characterization. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

Ce travail consiste en l'étude par RMN multinoyaux de matériaux paramagnétiques d'électrodes positives pour batteries au Li. La RMN du solide permet une caractérisation de l'environnement local du noyau sondé grâce à l'exploitation des interactions hyperfines dues à la présence d'une certaine densité d'électrons célibataires (déplacement de contact de Fermi) ou de conduction (déplacement de Knight) sur ce noyau (densité transférée selon des mécanismes plus ou moins complexes). Les matériaux étudiés sont des phosphates de métaux de transition tels que Li3M2(PO4)3 (M = Fe, V), la famille des tavorites LiMPO4X (M = Fe, Mn; X = OH, F) ou encore les phases homéotypiques MPO4.H2O (M = Fe, Mn, V). Pour tous ces matériaux, caractérisés par RMN du 7Li, 31P et 1H, l'environnement local de ces noyaux a été étudié afin d'envisager les mécanismes de transfert de spin possibles. Des calculs ab initio ont été effectués pour reproduir les déplacements de RMN, puis établir des cartes de densité de spin afin d'étayer ou compléter la compréhension de ces mécanismes.

The work presented in this Doctoral dissertation concerns the ability of heavy timber structures to passively reduce the fluctuations of the indoor temperature and of the indoor relative humidity, through the dynamic process of heat and moisture storage in wood. We make the hypothesis that the potential offered by the hygrothermal inertia of heavy timber structures is significant, and that it could provide a passive way of regulating the indoor climate. This ultimately could results in a decrease of the energy demand from the Heating, Ventilating and Air Conditioning systems. In this Thesis, the author tries to characterise and quantify the significance of the hygrothermal inertia providing by the heavy timber constructions. The experimental studies contain an in-situ measurement campaign carried out at the Vetenskapsstaden building located in Stockholm and erected in 2001. The results from the test campaign show that a heavy timber construction may contribute to buffer the indoor temperature. A direct quantification of the moisture stored in the wood structure is measured regarding the year-to-year indoor humidity fluctuations. It was however hardly possible to directly quantify the moisture storage potential offered by the structure regarding the day-to-day indoor relative humidity fluctuations because of the low sensitivity of the measuring technique used. In regard to the limitations noticed during the in-situ measurements, laboratory measurements were launched to develop new methods to determine the day-to-day hygric performances of wood exposed indoor. A new method based on the Magnetic Resonance Imaging technology was developed and is intended to provide information about the Moisture Buffer Value measured according to a NORDTEST protocol, and about the moisture distribution in wood with high spatial resolution. The Moisture Buffer Value of untreated Scots pine measured with this method is in accordance with the gravimetric method provided by the NORDTEST protocol. The Moisture Buffer Value of coated Scots pine was also investigated and it is normally assumed that any coatings will decrease the Moisture Buffering Capacity of the structure. The results show however that for specific coating such as waterborne alkali silicate coating, the Moisture Buffering Capacity of the structure may on the contrary be improved. At last, numerical simulations were carried out. They were based upon the extension of a modular simulation environment IDA ICE 3.0, with the implementation of a specific model for heat and moisture transport in a wood. The results obtained pinpoint the highly synergetic effects between the indoor moisture loads, the ventilation rate, the outdoor climate and the moisture interactions with the structure. The outcomes also show that the Moisture Buffering Capacity of a heavy timber structure is appreciable. The structure is able to even out substantially the day-to-day indoor relative humidity fluctuations for a certain range of ventilation rate. / QC 20100825