No description available.

<p>Karakterizacija&nbsp; ekstrakata&nbsp; plodnih&nbsp; tela&nbsp; devet&nbsp;autohtonih&nbsp; vrsta&nbsp; gljiva&nbsp; pripadnika&nbsp; razdela&nbsp;Basidiomycota&nbsp; obuhvatila&nbsp; je&nbsp; preliminarno&nbsp;ispitivanje&nbsp; hemijskog&nbsp; sastava&nbsp; i&nbsp; ispitivanje biolo&scaron;ke&nbsp; aktivnosti.&nbsp; Primenom&nbsp; HPLC‐MS/MS&nbsp; i&nbsp;GC-FID tehnike &nbsp;detektovan&nbsp;je&nbsp;i&nbsp;određen&nbsp;sadržaj&nbsp;fenolnih&nbsp;jedinjenja&nbsp;i&nbsp;metil&nbsp;estara&nbsp;masnih&nbsp;kiselina.&nbsp;<br />Primenom&nbsp; tehnike&nbsp; elektroforeze&nbsp; na&nbsp; mikročipu&nbsp;(&quot;LAB‐ON‐A‐CHIP&quot;&nbsp; kapilarnom&nbsp; elektroforezom)&nbsp;izvr&scaron;ena&nbsp;je&nbsp;karakterizacija&nbsp;proteinskih&nbsp;frakcija&nbsp;u&nbsp;odabranim&nbsp; vrstama&nbsp; gljiva.&nbsp; Antioksidantna&nbsp;aktivnost&nbsp; (sposobnost&nbsp; neutralizacije&nbsp; slobodnih &nbsp;radikala, &nbsp;redukcioni&nbsp;potencijal),&nbsp;sadržaj&nbsp;ukupnih&nbsp;fenola&nbsp; i&nbsp; flavonoida&nbsp; vodenih&nbsp; i&nbsp; etanolnih&nbsp;<br />ekstrakata&nbsp; ispitan&nbsp; je&nbsp; primenom&nbsp;spektrofotometrijskih&nbsp; metoda.&nbsp; Antimikrobna&nbsp;<br />aktivnost&nbsp; metanolnog&nbsp; i&nbsp; heksanskog&nbsp; ekstrakta&nbsp;ispitana&nbsp; je&nbsp; na&nbsp; Gram‐pozitivnim&nbsp; i&nbsp; Gram&ndash;negativnim bakterijskim&nbsp; sojevima.&nbsp; Efekat etanolnih&nbsp;i&nbsp;vodenih &nbsp;ekstrakata &nbsp;odabranih&nbsp;vrsta gljiva&nbsp; na&nbsp; rast&nbsp;ćelijske&nbsp; linije&nbsp; MCF7&nbsp; (humani adenokarcinom&nbsp;dojke pozitivan&nbsp;na&nbsp;estrogenske&nbsp;i progesteronske&nbsp;receptore),&nbsp;ispitan&nbsp;je&nbsp;MTT&nbsp;i&nbsp;SRB testom,&nbsp;dok&nbsp;je&nbsp;efekat&nbsp;frakcija&nbsp;ispitan&nbsp;primenom MTT&nbsp; testa.&nbsp; Sumarno,&nbsp; ukupni&nbsp; biopotencijal ispitivanih&nbsp;vrsta&nbsp;na&nbsp;osnovu&nbsp;sprovedenih&nbsp;analiza hemijske&nbsp; karakterizacije&nbsp; i&nbsp; biolo&scaron;kih&nbsp; testova upućuju&nbsp;opravdanost&nbsp;hipoteze&nbsp;da&nbsp;su&nbsp;odabrane vrste&nbsp;potencijalni &nbsp;izvori&nbsp;nutraceutika.&nbsp;Svakako&nbsp;je potrebno&nbsp;i&nbsp;neophodno&nbsp;nastaviti&nbsp;dalja&nbsp;istraživanja ovih&nbsp;vrsta.</p> / <p>Characterization&nbsp;of&nbsp;extracts&nbsp;of&nbsp;fruiting&nbsp;bodies&nbsp;of&nbsp;<br />nine&nbsp;native&nbsp;species&nbsp;of&nbsp;mushrooms&nbsp;members&nbsp;of&nbsp;<br />section&nbsp; Basidiomycota&nbsp; included&nbsp; preliminary&nbsp;<br />testing&nbsp; of&nbsp; chemical&nbsp; composition&nbsp; and&nbsp; biological&nbsp;<br />activity.&nbsp; Using&nbsp; HPLC‐MS&nbsp; /&nbsp; MS&nbsp; and&nbsp; GC‐FID&nbsp;<br />techniques&nbsp;the&nbsp;content&nbsp;of&nbsp;phenolic&nbsp;compounds&nbsp;<br />and&nbsp;fatty&nbsp;acid&nbsp;methyl&nbsp;esters&nbsp;has&nbsp;been&nbsp;detected&nbsp;<br />and&nbsp;determined.&nbsp;By&nbsp;applying&nbsp;the&nbsp;techniques&nbsp;of&nbsp;<br />electrophoresis&nbsp; on&nbsp; microchip&nbsp; (&quot;LAB‐ON‐A‐CHIP&quot;&nbsp;<br />capillary&nbsp; electrophoresis)&nbsp; characterization&nbsp; of&nbsp;<br />protein&nbsp;fractions&nbsp;in&nbsp;selected&nbsp;types&nbsp;of&nbsp;mushrooms&nbsp;<br />has&nbsp;been&nbsp;performed.&nbsp;The&nbsp;antioxidant&nbsp;activity&nbsp;(the&nbsp;<br />ability&nbsp; of&nbsp; neutralizing&nbsp; free&nbsp; radicals,&nbsp; reducing&nbsp;<br />potential),&nbsp; the&nbsp; contents&nbsp; of&nbsp; total&nbsp; phenols&nbsp; and&nbsp;<br />flavonoids&nbsp; of&nbsp; water&nbsp; and&nbsp; ethanol&nbsp; extracts&nbsp; has&nbsp;<br />been&nbsp; tested&nbsp; using&nbsp; the&nbsp; spectrophotometric&nbsp;<br />method.&nbsp; The&nbsp; antimicrobial&nbsp; activity&nbsp; of&nbsp; methanol&nbsp;<br />and&nbsp; hexane&nbsp; extracts&nbsp; was&nbsp; tested&nbsp; against&nbsp; Gram‐<br />positive&nbsp;and&nbsp;Gram‐negative&nbsp;bacterial&nbsp;strains.&nbsp;The&nbsp;<br />effect&nbsp; of&nbsp; ethanol&nbsp; and&nbsp; aqueous&nbsp; extracts&nbsp; of&nbsp;<br />selected&nbsp;fungi&nbsp;species&nbsp;on&nbsp;the&nbsp;growth&nbsp;of&nbsp;the&nbsp;cell&nbsp;<br />line&nbsp; MCF7&nbsp; (human&nbsp; breast&nbsp; adenocarcinoma&nbsp;<br />positive&nbsp; for&nbsp; estrogen&nbsp; and&nbsp; progesterone&nbsp;<br />receptors),&nbsp; has&nbsp; been&nbsp; examined&nbsp; using&nbsp; MTT&nbsp; and&nbsp;<br />SRB&nbsp;assay,&nbsp;while&nbsp;the&nbsp;effect&nbsp;of&nbsp;the&nbsp;fractions&nbsp;has&nbsp;<br />been&nbsp;tested&nbsp;by&nbsp;using&nbsp;the&nbsp;MTT&nbsp;assay.&nbsp;In&nbsp;summary,&nbsp;<br />the&nbsp;overall&nbsp;biological&nbsp;potential&nbsp;of&nbsp;the&nbsp;examined&nbsp;<br />species&nbsp; based&nbsp; on&nbsp; results&nbsp; for&nbsp; chemical&nbsp; and&nbsp;<br />biological&nbsp; characterization&nbsp; tests&nbsp; (anti‐oxidative,&nbsp;<br />antimicrobial&nbsp;and&nbsp;anti‐proliferative)&nbsp;indicate&nbsp;the&nbsp;<br />justifiability&nbsp; of&nbsp; the&nbsp; hypothesis&nbsp; that&nbsp; examined&nbsp;<br />species&nbsp; of&nbsp; mushrooms&nbsp; are&nbsp; potential&nbsp; sources&nbsp; of&nbsp;<br />nutraceuticals.&nbsp; It&nbsp; is&nbsp; certainly&nbsp; needed&nbsp; and&nbsp;<br />necessary&nbsp;to&nbsp;continue&nbsp;further&nbsp;research&nbsp;of&nbsp;these&nbsp;<br />species.</p>

L'analyse dynamique intègre des outils propres aux systèmes dynamiques (comme l'opérateur de transfert) au cadre de la combinatoire analytique, et permet ainsi l'analyse d'un grand nombre d'algorithmes et objets qu'on peut associer naturellement à un système dynamique. Dans ce manuscrit de thèse, nous présentons, dans la perspective de l'analyse dynamique, l'étude probabiliste de plusieurs problèmes qui semblent à priori bien différents : l'analyse probabiliste de la fonction de récurrence des mots de Sturm, et l'étude probabiliste de l'algorithme du “logarithme continu”. Les mots de Sturm constituent une famille omniprésente en combinatoire des mots. Ce sont, dans un sens précis, les mots les plus simples qui ne sont pas ultimement périodiques. Les mots de Sturm ont déjà été beaucoup étudiés, notamment par Morse et Hedlund (1940) qui en ont exhibé une caractérisation fondamentale comme des codages discrets de droites à pente irrationnelle. Ce résultat relie ainsi les mots de Sturm au système dynamique d'Euclide. Les mots de Sturm n'avaient jamais été étudiés d'un point de vue probabiliste. Ici nous introduisons deux modèles probabilistes naturels (et bien complémentaires) et y analysons le comportement probabiliste (et asymptotique) de la “fonction de récurrence” ; nous quantifions sa valeur moyenne et décrivons sa distribution sous chacun de ces deux modèles : l'un est naturel du point de vue algorithmique (mais original du point de vue de l'analyse dynamique), et l'autre permet naturellement de quantifier des classes de plus mauvais cas. Nous discutons la relation entre ces deux modèles et leurs méthodes respectives, en exhibant un lien potentiel qui utilise la transformée de Mellin. Nous avons aussi considéré (et c'est un travail en cours qui vise à unifier les approches) les mots associés à deux familles particulières de pentes : les pentes irrationnelles quadratiques, et les pentes rationnelles (qui donnent lieu aux mots de Christoffel). L'algorithme du logarithme continu est introduit par Gosper dans Hakmem (1978) comme une mutation de l'algorithme classique des fractions continues. Il calcule le plus grand commun diviseur de deux nombres naturels en utilisant uniquement des shifts binaires et des soustractions. Le pire des cas a été étudié récemment par Shallit (2016), qui a donné des bornes précises pour le nombre d'étapes et a exhibé une famille d'entrées sur laquelle l'algorithme atteint cette borne. Dans cette thèse, nous étudions le nombre moyen d'étapes, tout comme d'autres paramètres importants de l'algorithme. Grâce à des méthodes d'analyse dynamique, nous exhibons des constantes mathématiques précises. Le système dynamique ressemble à première vue à celui d'Euclide, et a été étudié d'abord par Chan (2005) avec des méthodes ergodiques. Cependant, la présence des puissances de 2 dans les quotients change la nature de l'algorithme et donne une nature dyadique aux principaux paramètres de l'algorithme, qui ne peuvent donc pas être simplement caractérisés dans le monde réel.C'est pourquoi nous introduisons un nouveau système dynamique, avec une nouvelle composante dyadique, et travaillons dans ce système à deux composantes, l'une réelle, et l'autre dyadique. Grâce à ce nouveau système mixte, nous obtenons l'analyse en moyenne de l'algorithme. / Dynamical Analysis incorporates tools from dynamical systems, namely theTransfer Operator, into the framework of Analytic Combinatorics, permitting the analysis of numerous algorithms and objects naturally associated with an underlying dynamical system.This dissertation presents, in the integrated framework of Dynamical Analysis, the probabilistic analysis of seemingly distinct problems in a unified way: the probabilistic study of the recurrence function of Sturmian words, and the probabilistic study of the Continued Logarithm algorithm.Sturmian words are a fundamental family of words in Word Combinatorics. They are in a precise sense the simplest infinite words that are not eventually periodic. Sturmian words have been well studied over the years, notably by Morse and Hedlund (1940) who demonstrated that they present a notable number theoretical characterization as discrete codings of lines with irrationalslope, relating them naturally to dynamical systems, in particular the Euclidean dynamical system. These words have never been studied from a probabilistic perspective. Here, we quantify the recurrence properties of a ``random'' Sturmian word, which are dictated by the so-called ``recurrence function''; we perform a complete asymptotic probabilistic study of this function, quantifying its mean and describing its distribution under two different probabilistic models, which present different virtues: one is a naturaly choice from an algorithmic point of view (but is innovative from the point of view of dynamical analysis), while the other allows a natural quantification of the worst-case growth of the recurrence function. We discuss the relation between these two distinct models and their respective techniques, explaining also how the two seemingly different techniques employed could be linked through the use of the Mellin transform. In this dissertation we also discuss our ongoing work regarding two special families of Sturmian words: those associated with a quadratic irrational slope, and those with a rational slope (not properly Sturmian). Our work seems to show the possibility of a unified study.The Continued Logarithm Algorithm, introduced by Gosper in Hakmem (1978) as a mutation of classical continued fractions, computes the greatest common divisor of two natural numbers by performing division-like steps involving only binary shifts and substractions. Its worst-case performance was studied recently by Shallit (2016), who showed a precise upper-bound for the number of steps and gave a family of inputs attaining this bound. In this dissertation we employ dynamical analysis to study the average running time of the algorithm, giving precise mathematical constants for the asymptotics, as well as other parameters of interest. The underlying dynamical system is akin to the Euclidean one, and was first studied by Chan (around 2005) from an ergodic, but the presence of powers of 2 in the quotients ingrains into the central parameters a dyadic flavour that cannot be grasped solely by studying this system. We thus introduce a dyadic component and deal with a two-component system. With this new mixed system at hand, we then provide a complete average-case analysis of the algorithm by Dynamical Analysis.

The work deals with the examination of repression and segregation in asphalt mixtures. The theoretical part is monitoring the current situation about the problem of segregation, which mainly refers to the practical adjustments during laying „risking“ asphalt mixtures on the formation of segregated places in the shelter layers of roads. The practical parts of the thesis are summarised measurements on six samples of the most commonly used asphalt mixtures to determine the segregation depending on the selected parameters. The work is describing and valorising a test for determining segregation according to ČSN EN 12697-15.

PhD (Microbiology) / Department of Microbiology / Background: Currently, Human Immunodeficiency Virus/ Acquired Immune Deficiency Syndrome (HIV/AIDS) is one of the deadliest diseases in the world. In Gabon, the prevalence is estimated at 4.1%. Because of the several side effects of highly active antiretroviral therapy on the health of people living with HIV, an emphasis on the utilization of based plant treatments have been noticed highlighted with testimonies of patient health improvement. That led researchers to conduct ethnobotanical surveys aiming at reporting medicinal plants used to treat HIV related opportunistic infections. From the outcomes, 20 plants have been selected based on the frequency of their use but also on the absence of papers in the literature related to HIV research conducted in Gabon. This study aims at evaluating the cytotoxicity, antioxidant, antimicrobial, anti-HIV and immunomodulatory activities of the 20 selected plants and to establish the phytochemical profile of these plants. Methodology: The plants were extracted using absolute methanol and distilled water. Qualitative (phytochemical screening) and quantitative (TPC and TFC) analysis were performed on the 40 extracts obtained. The extracts were assessed for cytotoxicity on Vero and HeLa cells using MTT and dual staining/fluorescence microscopy. The antimicrobial activity of the extracts was evaluated using well diffusion assay and micro-broth dilution assay. DPPH free radical scavenging assay and ferric reducing power were used to determine the antioxidant potential of the extracts. The anti-HIV effect was evaluated on HIV infected blood using reverse transcriptase inhibitory assay and p24 antigen inhibitory assay. The immunomodulatory effects of the extracts were evaluated on HIV infected blood using IL-2, IL-6 and TNF-α ELISA. Coula edulis and T. iboga methanol extracts were selected for fractionation using column chromatography. LC-MS was used to establish the phytochemical profile of the two selected extracts. Results: The results revealed that saponins, alkaloids, terpenoids, phenols, tannins, steroids, flavonoids and cardiac glycosides were detected in almost all the plant extracts. The extracts were found to contain more phenolics than flavonoids especially the methanolic extracts. Both alcoholic and aqueous extracts of C. edulis, M. cecropioides, S. ochocoa, S. kamerounensis, U. guineensis and C. religiosa, the methanolic extract of A. hirtella and R. vomitoria and the aqueous extracts of U. klainei presented IC50 significantly lower (p<0.05) than ascorbic acid (38.87±1.54 μg/ml). Both Coula edulis methanolic and aqueous extracts, methanolic extracts of S. kamerounensis, S. gabonensis, M. monandra, U.guineensis and A. klaineana showed antioxidant activity significantly xii | P a g e (p<0.01) higher than Ascorbic acid whose EC50 was 152.16±1.09 μg/ml. For the fluorescence microscopy the extracts of interest for Vero cells inhibition were A. klaineana, T. iboga, U. klainei and C. edulis while for Hela cells the cytotoxic activity was significant (p<0.05) for the following extracts: U. klainei, U. guineensis, P. soyauxii, A. klaineana, V. conferta, M. monandra, R. vomitoria, R. africanum, C. edulis and S. ochocoa. The extracts of C. edulis, M. cecropioides, S. ochocoa, S. gabonensis, A. hirtella, R. vomitoria, S. kamerunensis, P. soyauxii, U. guineensis and T. iboga displayed the highest antimicrobial activity against all the selected bacteria. For the anti-HIV the extracts of interest were V. conferta (47%), C. lucanusianus (47%), C. religiosa (44%), A. hirtella (42%), S. kamerunensis (41%), M. puberula (41%) as well as both aqueous and methanolic extracts of T. iboga (48% and 45% respectively), U. guineensis (46% and 41% respectively) and A. klaineana (41% and 44% respectively). The results for RT inhibition assay revealed that out of 24 selected plant extracts selected only C. edulis, C. religiosa, C. lucanusianus, R. africanum, P. soyauxii and V. conferta were able to decrease RT by more than 50%. The modulatory effect of the extracts on the secretion of IL-2, IL-6 and TNF-α by HIV infected cells was found to be insignificant (p>0.05). The fractionation of T. iboga and C. edulis methanol extracts eluted 4 fractions each. The LC-MS analysis revealed at negative ionization the presence of phenolic compounds (Ellagic acid, Gallic acid, and quercetin) in C. edulis samples while alkaloids (ibogaine, ibogaline, voacangine) were mainly found in T. iboga samples at positive ionization. The two crude extracts and the fractions showed some levels of antimicrobial, antioxidant, anti-HIV and anti-inflammatory activities. Conclusion: The present study has validated the use of the selected plants in the management of AIDS in Gabon and provided an explanation of the improvement in HIV individual’s life reported. Some of these plants could constitute good candidate for promising anti-HIV molecules. / NRF

La contamination en composés aromatiques polycycliques (CAP) a été suivie entre 2014 et 2015 au cours de six campagnes d’échantillonnage sur 8 sites différents entre Auboué et Richemont. Cette section du cours d’eau correspond à la partie aval de la vallée de l’Orne profondément affectée par plus d’un siècle d’activités minières et sidérurgiques qui ont cessé entre 1968 et 2009. L’Orne a donc été le réceptacle de rejets industriels et urbains et a été profondément perturbée dans son hydrodynamisme avec la construction de plusieurs barrages. Dans ce contexte, l’occurrence des 16 hydrocarbures aromatiques polycycliques réglementaires (HAP), de 11 CAP oxygénés (O-CAP) et de 5 CAP azotés (N-CAP) et leur distribution dans les fractions dissoute et particulaire des eaux de l’Orne ont été étudiées en mettant en place des protocoles d’échantillonnage et d’analyse adaptés. Le premier objectif de ce travail a été de comparer les méthodes d’échantillonnage des matières en suspension par filtration et par centrifugation à flux continu sur le terrain. Des différences significatives ont pu être identifiées entre les deux techniques, la filtration amenant à des concentrations en CAP plus élevées du fait d’une plus grande abondance des CAP de bas poids moléculaire. Nous avons pu mettre en évidence le rôle de la fraction fine (< 5µm) et/ou colloïdale plus ou moins retenue par les filtres et qui, de part sa réactivité, piège des CAP. La comparaison des deux méthodes dans différentes situations hydrologiques nous montre que cette rétention n’est pas systématique mais plutôt corrélée à des situations de fort hydrodynamisme. Les deux méthodes d’échantillonnage des matières en suspension ne sont donc pas comparables mais complémentaires. Le suivi saisonnier et multi-sites des eaux de l’Orne montre que la concentration en CAP varie entre 1.6 et 223.7 ng L-1 dans la fraction dissoute et entre 1.5 et 105.5 µg g-1 dans la fraction particulaire avec des variations spatiales de ±35% et ±45% respectivement. Les variations de concentration des CAP dans la fraction dissoute sont importantes d’un site à l’autre lorsque le débit est faible (de 0.5 à 34 m3.s-1). Les concentrations en CAP sont faibles autour de 20 ng.L-1 et spatialement homogènes en périodes de haut débit (> 50 m3.s-1) du fait de la dilution. Les concentrations en CAP dans les matières en suspension varient entre 2.8 to 36.3 µg g-1, et montrent des concentrations stables quelles que soient les situations hydrologiques lorsqu’elles sont collectées par la centrifugeuse de terrain. La fraction dissoute est enrichie en HAP de bas poids moléculaire dans les périodes d’étiage et est marquée par l’occurrence des HAP à 5 et 6 cycles aromatiques au cours des épisodes de crue. Les CAP polaires sont au moins aussi abondants que les HAP dans la fraction dissoute et évoluent de la même façon que les HAP. La part des CAP polaires dans la fraction particulaire est significativement plus basse (de 10 à 20% de l’ensemble des CAP) / The spatio-temporal variations of the concentration and distribution of dissolved and particulate polycyclic aromatic compounds (PACs), namely 16 polycyclic aromatic hydrocarbons (PAHs), 11 oxygenated PACs (O-PACs) and 5 nitrogen PACs (N-PACs), were studied in the Orne, a river impacted for more than one century by iron mining and steel-making industry. The first objective of this work was to compare the influence of two different methods of separation of suspended particulate matter (SPM), filtration (FT) and field continuous flow centrifuge (CFC). Results showed that in half of the sampling campaigns, PAC concentrations were 2 to 8 times higher for PAHs and 2 to 10 times higher for O-PAC when SPM were collected by filtration. These differences that were not observed systematically over the six sampling campaigns could be explained by the retention of colloidal matter on glass-fiber filters that appeared as a very reactive phase particularly enriched in low molecular PACs. The two methods were then considered as complementary methods to study SPM. The second objective of this work was to perform a long term monitoring of PAC concentrations and distributions in dissolved and particulate fractions. The results from the six sampling campaigns between May 2014 and September 2015 in eight different sites showed that the PAC concentrations ranged between 1.6 to 223.7 ng L-1 in the dissolved fraction (?PACTD), and between 1,55 to 105,5 µg g-1 in the total particulate fraction, with maximum spatial variation of ±35% and ±45% respectively. The dissolved PACs spatial variations were strongly influenced by the hydrological conditions and less spatial variation was observed during high flow events as the result of dilution and homogenization of pollutants. During low flow events, particulate PACSPM-CFC concentrations were more stable and equivalent in values and distribution to the corresponding PACSPM-FT samples. Overall it was in a range between 2.8 to 36.3 µg g-1. The dominance of dissolved low molecular weight PAHTD in the low flow events decreased during high flow events due to the appearance of penta- and hexa-cyclic PAHs. The dissolved polar PACs were as high as the PAHs contribution and also subjected to seasonal changes, the O-PACs ranged between 5.6 to 90.3 ng L-1 and N-PAHs from 1.0 to 42.5 ng L-1. The particulate polar PACs concentrations and contribution were significantly lower, the highest concentrations of 8,76 µg g-1 and 29,41 µg g-1 was observed during high flow event for O-PACs and during low flow event for N-PAH respectively

The nuclear lamina protein, lamin A is produced by proteolytic cleavage of a 74 kDa precursor protein, prelamin A. The conversion of this precursor to mature lamin A is mediated by a specific endoprotease, prelamin A endoprotease. Subnuclear fractionation indicates that the prelamin A endoprotease is localized at the nuclear membrane. The enzyme appears to be an integral membrane protein, as it can only be removed from the nuclear envelope with detergent. It is effectively solubilized by the detergent n-octyl-beta-D-glucopyranoside and can be partially-purified (approximately 1200-fold) by size exclusion and cation exchange (Mono S) chromatography. Prelamin A endoprotease from HeLa cells was eluted from Mono S with 0.3 M sodium chloride as a single peak of activity. SDS-PAGE analysis of this prelamin A endoprotease preparation shows that it contains one major polypeptide at 65 kDa and smaller amounts of a second 68 kDa polypeptide. Inhibition of the enzyme activity in this preparation by specific serine protease inhibitors is consistent with the enzyme being a serine protease.

Certaines caractéristiques des ressources numériques sont de nature à soutenir les apprentissages de tous les élèves en classe. L’étude de Cyr, Charland et Riopel (2016) permet notamment d’observer un effet significatif sur l’apprentissage du concept de fraction lorsque les élèves réalisent les parcours de l’application Slice Fractions. Toutefois, l’intégration de cette ressource à l’enseignement régulier en classe n’accroit pas cet effet. Notre recherche-action vise à soutenir l’intégration de ressources numériques à des pratiques pédagogiques efficaces par le biais d’un dispositif de développement professionnel jumelant un cercle pédagogique et un soutien en classe. Elle a été réalisée auprès de trois enseignantes de trois classes d’une école primaire afin de mieux comprendre comment intégrer efficacement les pratiques pédagogiques et les ressources numériques en classe pour mieux soutenir les apprentissages de tous les élèves. Nous avons observé les pratiques pédagogiques et le processus d’apprentissage des élèves en classe. Nous avons aussi étudié l’apport d’un dispositif de développement professionnel pour soutenir le développement des pratiques dans une perspective d’intégration de ressources numériques. L’analyse qualitative est basée sur la documentation sur vidéo des pratiques pédagogiques des enseignantes, de la démarche de leurs élèves et des cercles pédagogiques. Nos résultats suggèrent que les pratiques pédagogiques mises en œuvre dans ce contexte permettent de mieux soutenir le développement du raisonnement, du métalangage et de l’autorégulation chez tous les élèves. L’ajout d’un dispositif numérique permet également aux enseignantes de segmenter les problèmes à résoudre et de recueillir les réponses de tous les élèves. Ce processus soutient et influe sur leur évaluation du niveau de compréhension des élèves. Les échanges en cercle pédagogique et le soutien en classe contribuent également au développement de la capacité des enseignantes à discerner des éléments importants dans le processus et guident leur planification des activités subséquentes. / Some attributes of digital resources are likely to support the learning of all students. In the study by Cyr, Charland and Riopel (2016), a significant effect on the learning of the concept of fraction was observed when students worked through all levels of the application Slice Fractions. However, the implementation of this resource in regular classroom instruction did not increase this effect. Our action research aims to support the integration of digital resources with effective teaching practices through a professional development intervention combining video clubs and in-class assistance. It was conducted with three teachers in three classes of an elementary school to better understand how to conduct an effective integration of teaching practices and digital resources in the classroom to better facilitate the learning of all students. We observed the teaching practices and the learning process of students in class. We also studied the contribution of a professional development intervention to support the development of teaching practices within a context where digital resources are implemented in the classroom. Qualitative measures are based on the analysis of video documentation of the teachers’ practices, their students’ learning process and the video clubs. Our results suggest that the teaching practices implemented in this setting better support the development of reasoning, metalanguage, and self-regulation among all students. The use of an additional digital resource also allows teachers to break down the problems to be solved and collect responses from all students. It supports this process and influences their evaluation of the students’ level of understanding. The video club discussions and the in-class assistance also contribute to the development of teachers’ ability to discern important elements in the students’ learning process and guide their planning of subsequent activities. Our results inform the discussion on the nature of teaching practices that are likely to promote the implementation of digital resources and foster learning for all students, as well as on the impact of video clubs and in-class assistance and the conditions that strengthen their effectiveness in this type of context.

No description available.

Soil organic matter (OM) is a complex mixture of compounds, mainly derived from plants and microbes at various states of decay. It is part of the global carbon cycle and is important for maintaining soil quality. OM protection is mainly attributed to its association with minerals. However, clay minerals preferentially sorb specific OM structures, and clay sorption sites become saturated as OM concentrations increase. Therefore, it is important to examine how OM structures influence their association with soil minerals, and to characterize other protection mechanisms. Several techniques, which provide complementary information, were combined to investigate OM composition: Biomarker (lignin phenol, cutin-OH acid, and lipid) analysis, using gas chromatography/mass spectrometry; solid-state 13C nuclear magnetic resonance (NMR) spectroscopy; and an emerging method, solution-state 1H NMR spectroscopy. OM composition of sand-, silt-, clay-size, and light fractions of Canadian soils were compared. It was found that microbial-derived and aliphatic structures accumulated in clay-size fractions, and lignin phenols in silt-size fractions may be protected from further oxidation. Therefore, OM protection through association with minerals may be structure-specific. OM in soils amended with maize leaves, stems, and roots from a biodegradation study were also examined. Over time, lignin phenol composition, and oxidation; and aliphatic structure contribution changed less in soils amended with leaves compared to soils amended with stems and roots. Compared to soils amended with leaves and stems, amendment with roots may have promoted the more efficient formation of microbial-derived OM. Therefore, plant chemistry influenced soil OM turnover. Synthetic OM-clay complexes and soil mineral fractions were used to investigate lignin protection from chemical oxidation. Coating with dodecanoic acid protected lignin from chemical oxidation, and overlying vegetation determined the relative resistance of lignin phenols in clay-size fractions from chemical oxidation. Therefore, additional protection from chemical oxidation may be attributed to OM composition and interactions between OM structures sorbed to clay minerals. Overall, these studies suggest that while association with minerals is important, OM turnover is also influenced by vegetation, and protection through association with clay minerals was modified by OM structure composition. As well, OM-OM interaction is a potential mechanism that protects soil OM from degradation.