Etude in vitro de l'activité électrique du tissu nerveux obtenu par culture de biopsies cérébrales humaines adultes

Récemment encore, la neuro-genèse chez le primate adulte était supposée limitée aux régions précises que sont le bulbe olfactif, la zone sous-granulaire de l'hippocampe et la région sous- ventriculaire. Depuis lors, des cellules neurales progénitrices distribuées dans l'ensemble du cortex du primate adulte furent mises en évidence. Cultivées in vitro, ces cellules forment des écosystèmes cellulaires nerveux constitués de progéniteurs neuronaux, d'astrocytes et d'oligo- dendrocytes. Transplantés sur un modèle de primate parkinsonien, certains progéniteurs complètent leur différentiation en neurones matures et développent des propriétés neuro- trophiques et neuro-protectrices. Injectées aux environs d'une lésion cérébrale, ces cellules offrent un bénéfice fonctionnel et comportemental significatif. Le présent projet mesure l'activité électro-physiologique du tissu nerveux obtenu par culture de biopsies corticales humaines adultes, de sorte à déterminer son aptitude à intégrer l'information. Des biopsies corticales humaines adultes furent cultivées in vitro avec succès sur un support Micro-Electrode-Array. Cette technologie permet l'acquisition d'enregistrements électro- physiologiques à l'échelle des circuits, au sein d'un tissu maintenu en culture. En parallèle, une mesure de l'activité à l'échelle cellulaire fut obtenue par l'application du Patch Clamp à des cellules cultivées sur un support de verre. Malgré une culture prolongée et l'induction d'une différentiation neuronale, aucune activité électro-physiologique significative ne put être démontrée. Une analyse phénotypique à un stade intermédiaire de culture montra l'expression prometteuse du marqueur neuronal précoce β-Tubulin-III. Cependant, après l'induction d'une différenciation neuronale, la surprenante co-expression de marqueurs astroglial (GFAP) et neuronal (MAP2) fut constatée. Le silence électro-physiologique issu des enregistrements sur MEA peut être l'oeuvre d'un isolement des cellules électriquement actives, et d'un défaut d'organisation en réseau. Une interposition de tissu glial entre neurones et électrodes peut également absorber le signal. Par ailleurs, les cellules enregistrées par Patch Clamp furent déterminées selon le seul critère morphologique ; leur nature exacte demeure inconnue. Les analyses phénotypiques laissent supposer l'entrée dans une voie de maturation neuronale par l'expression du marqueur β- Tubulin-III. Toutefois le phénotype exprimé au terme du processus de culture reste incertain. Des facteurs de maturation ou environnementaux semblent faire défaut à la complétion d'une différentiation neuronale. La culture de neurones bien différenciés et électriquement actifs appelle de nouvelles études in vivo, ainsi qu'une analyse fine des voies intracellulaires de maturation.

Comparing multiple criteria for species identification in two recently diverged seabirds

Correct species identification is a crucial issue in systematics with key implications for prioritising conservation effort. However, it can be particularly challenging in recently diverged species due to their strong similarity and relatedness. In such cases, species identification requires multiple and integrative approaches. In this study we used multiple criteria, namely plumage colouration, biometric measurements, geometric morphometrics, stable isotopes analysis (SIA) and genetics (mtDNA), to identify the species of 107 bycatch birds from two closely related seabird species, the Balearic (Puffinus mauretanicus) and Yelkouan (P. yelkouan) shearwaters. Biometric measurements, stable isotopes and genetic data produced two stable clusters of bycatch birds matching the two study species, as indicated by reference birds of known origin. Geometric morphometrics was excluded as a species identification criterion since the two clusters were not stable. The combination of plumage colouration, linear biometrics, stable isotope and genetic criteria was crucial to infer the species of 103 of the bycatch specimens. In the present study, particularly SIA emerged as a powerful criterion for species identification, but temporal stability of the isotopic values is critical for this purpose. Indeed, we found some variability in stable isotope values over the years within each species, but species differences explained most of the variance in the isotopic data. Yet this result pinpoints the importance of examining sources of variability in the isotopic data in a case-by-case basis prior to the cross-application of the SIA approach to other species. Our findings illustrate how the integration of several methodological approaches can help to correctly identify individuals from recently diverged species, as each criterion measures different biological phenomena and species divergence is not expressed simultaneously in all biological traits.

Re-visiting the health care luxury good hypothesis: Aggregation, precision, and publication biases?

[cat] Mentre que una creixent literatura que ha examinat la relació entre la renda i la despesa sanitària suggereix que els serveis sanitaris són un be de luxe (elasticitat renda superior a la unitat), aquesta conclusió es contínuament debatuda atesa l'heterogeneïtat dels resultats. Aquest article testa la hipòtesis dels serveis sanitaris com bens de luxe fent server anàlisi de meta- regressió, particularment analitzant l'existència de biaixos de selecció de publicació, precisió així com biaixos d'agregació. Els resultats apunten l'existència d'un biaix de publicació, robust independentment dels controls analitzats. Els biaixos de precisió i agregació semblen tenir un paper en la generació de les estimacions de l'elasticitat renda. Els nostres resultat suggereixen que l'elasticitat renda dels serveis sanitaris un cop corregir pels biaixos esmentat varien entre 0.26 i 0.84, però no podem rebutjar que la elasticitat renda es igual a la unitat en algunes estimacions de l'elasticitat corregides.

Re-visiting the health care luxury good hypothesis: Aggregation, precision, and publication biases?

[cat] Mentre que una creixent literatura que ha examinat la relació entre la renda i la despesa sanitària suggereix que els serveis sanitaris són un be de luxe (elasticitat renda superior a la unitat), aquesta conclusió es contínuament debatuda atesa l'heterogeneïtat dels resultats. Aquest article testa la hipòtesis dels serveis sanitaris com bens de luxe fent server anàlisi de meta- regressió, particularment analitzant l'existència de biaixos de selecció de publicació, precisió així com biaixos d'agregació. Els resultats apunten l'existència d'un biaix de publicació, robust independentment dels controls analitzats. Els biaixos de precisió i agregació semblen tenir un paper en la generació de les estimacions de l'elasticitat renda. Els nostres resultat suggereixen que l'elasticitat renda dels serveis sanitaris un cop corregir pels biaixos esmentat varien entre 0.26 i 0.84, però no podem rebutjar que la elasticitat renda es igual a la unitat en algunes estimacions de l'elasticitat corregides.

Espectrometria de absorção atômica com atomização eletrotérmica em filamento de tungstênio: uma re-visão crítica

In this review it is presented some aspects of electrothermal atomic absorption spectrometry with tungsten coil (ETAW-AAS) since its beginning until the present days as well as the perspectives for this technique. Some aspects concerning its development and theoretical concepts are discussed. The analytical figures of merit such as limit of detection (LD), characteristic mass (m0), relative standard deviation (RSD), accuracy and precision are evaluated, compared and discussed considering published works. It is also evaluated its advantages, applications, limitations and instrumental development. The use of diode laser as radiation source and its perspectives to ETAW are also discussed.

Polyphenol intake and mortality risk: a re-analysis of the PREDIMED trial

Background: Polyphenols may lower the risk of cardiovascular disease (CVD) and other chronic diseases due to their antioxidant and anti-inflammatory properties, as well as their beneficial effects on blood pressure, lipids and insulin resistance. However, no previous epidemiological studies have evaluated the relationship between the intake of total polyphenols intake and polyphenol subclasses with overall mortality. Our aim was to evaluate whether polyphenol intake is associated with all-cause mortality in subjects at high cardiovascular risk. Methods: We used data from the PREDIMED study, a 7,447-participant, parallel-group, randomized, multicenter, controlled five-year feeding trial aimed at assessing the effects of the Mediterranean Diet in primary prevention of cardiovascular disease. Polyphenol intake was calculated by matching food consumption data from repeated food frequency questionnaires (FFQ) with the Phenol-Explorer database on the polyphenol content of each reported food. Hazard ratios (HR) and 95% confidence intervals (CI) between polyphenol intake and mortality were estimated using time-dependent Cox proportional hazard models. Results: Over an average of 4.8 years of follow-up, we observed 327 deaths. After multivariate adjustment, we found a 37% relative reduction in all-cause mortality comparing the highest versus the lowest quintiles of total polyphenol intake (hazard ratio (HR) = 0.63; 95% CI 0.41 to 0.97; P for trend = 0.12). Among the polyphenol subclasses, stilbenes and lignans were significantly associated with reduced all-cause mortality (HR =0.48; 95% CI 0.25 to 0.91; P for trend = 0.04 and HR = 0.60; 95% CI 0.37 to 0.97; P for trend = 0.03, respectively), with no significant associations apparent in the rest (flavonoids or phenolic acids). Conclusions: Among high-risk subjects, those who reported a high polyphenol intake, especially of stilbenes and lignans, showed a reduced risk of overall mortality compared to those with lower intakes. These results may be useful to determine optimal polyphenol intake or specific food sources of polyphenols that may reduce the risk of all-cause mortality.

El reposicionamiento: análisis conceptual y causal del fenómeno desde su origen hasta el (re)planteamiento actual

El present estudi té com a finalitat estudiar què és el reposicionament i quins són els factors que l’envolten. Pretén establir quines són les principals causes que condueixen a reposicionar una marca, així com també analitzar si el reposicionament és equivalent que quan va sorgir, o si pel contrari ha evolucionat, i com ho ha fet. Amb aquest estudi intentarem esbrinar com es reposicionen les marques en l’actualitat.

Determinação da origem biossintética de ácido acético através da técnica "Site Specific Natural Isotopic Fractionation Studied by Nuclear Magnetic Resonance (SNIF-NMR)"

The main purpose of this work is to describe the use of the technique Site-Specific Natural Isotopic Fractionation of hydrogen (SNIF-NMR), using ²H and ¹H NMR spectroscopy, to investigate the biosynthetic origin of acetic acid in commercial samples of Brazilian vinegar. This method is based on the deuterium to hydrogen ratio at a specific position (methyl group) of acetic acid obtained by fermentation, through different biosynthetic mechanisms, which result in different isotopic ratios. We measured the isotopic ratio of vinegars obtained through C3, C4, and CAM biosynthetic mechanisms, blends of C3 and C4 (agrins) and synthetic acetic acid.

Patriarchal hauntings : re-reading villainy and gender in Daphne du Maurier’s 'Rebecca'

Daphne du Maurier’s popular classic Rebecca (1938) was traditionally marketed as a Gothic romance in which two lovers conquered the evil women that separated them. In more recent years, some feminist critics have provided a very different view of the story as a Gothic narrative about the dangers women suffer under patriarchal control. In this thesis, I propose, through a Gothic Studies and a Gender Studies reading, that the victim/abuser statuses in du Maurier’s novel cannot be equated to femininity and masculinity, respectively. Instead, I argue that villainy in Rebecca comes from being in a powerful position within patriarchy—a position that is occupied by both male and female characters

Minimization of the experimental workload for the prediction of pollutants propagation in rivers. Mathematical modelling and knowledge re-use

The present thesis in focused on the minimization of experimental efforts for the prediction of pollutant propagation in rivers by mathematical modelling and knowledge re-use. Mathematical modelling is based on the well known advection-dispersion equation, while the knowledge re-use approach employs the methods of case based reasoning, graphical analysis and text mining. The thesis contribution to the pollutant transport research field consists of: (1) analytical and numerical models for pollutant transport prediction; (2) two novel techniques which enable the use of variable parameters along rivers in analytical models; (3) models for the estimation of pollutant transport characteristic parameters (velocity, dispersion coefficient and nutrient transformation rates) as functions of water flow, channel characteristics and/or seasonality; (4) the graphical analysis method to be used for the identification of pollution sources along rivers; (5) a case based reasoning tool for the identification of crucial information related to the pollutant transport modelling; (6) and the application of a software tool for the reuse of information during pollutants transport modelling research. These support tools are applicable in the water quality research field and in practice as well, as they can be involved in multiple activities. The models are capable of predicting pollutant propagation along rivers in case of both ordinary pollution and accidents. They can also be applied for other similar rivers in modelling of pollutant transport in rivers with low availability of experimental data concerning concentration. This is because models for parameter estimation developed in the present thesis enable the calculation of transport characteristic parameters as functions of river hydraulic parameters and/or seasonality. The similarity between rivers is assessed using case based reasoning tools, and additional necessary information can be identified by using the software for the information reuse. Such systems represent support for users and open up possibilities for new modelling methods, monitoring facilities and for better river water quality management tools. They are useful also for the estimation of environmental impact of possible technological changes and can be applied in the pre-design stage or/and in the practical use of processes as well.

Analytical procedures for determining Pb and Sr isotopic compositions in water samples by ID-TIMS

Few articles deal with lead and strontium isotopic analysis of water samples. The aim of this study was to define the chemical procedures for Pb and Sr isotopic analyses of groundwater samples from an urban sedimentary aquifer. Thirty lead and fourteen strontium isotopic analyses were performed to test different analytical procedures. Pb and Sr isotopic ratios as well as Sr concentration did not vary using different chemical procedures. However, the Pb concentrations were very dependent on the different procedures. Therefore, the choice of the best analytical procedure was based on the Pb results, which indicated a higher reproducibility from samples that had been filtered and acidified before the evaporation, had their residues totally dissolved, and were purified by ion chromatography using the Biorad® column. Our results showed no changes in Pb ratios with the storage time.

De re vestiaria

Invocatio: Q.F.F.Q.S.

Dissertatio metaphysica Kantianorum de re in se (Ding an sich) doctrinam breviter examinans. Quam cons. ampl. facult. philos. Aboënsis. Publico examini modeste offerunt Fredericus Bergbom

Painovuosi nimekkeestä.