Cette thèse a pour vocation de contribuer au développement de différents immunocapteurs ampérométriques associés aux électrodes sérigraphiées (SPE). Les immunocapteurs sont des dispositifs simples associant un anticorps ou un antigène qui assurent la sélectivité à un transducteur (ici une SPE) ;ce dernier transforme la liaison anticorps/antigène en un signal mesurable (ici ampérométrique).<p>Le travail est divisé en deux volets principaux.<p>Le premier est consacré à la mise en œuvre de différents modèles d’immunocapteurs ampérométriques pour le dosage d’anticorps anti-tetani. La vaccination contre le tétanos est généralisée, toutefois pour maintenir un taux d’anticorps suffisant, il est indispensable d’administrer un rappel tous les 10 ans. Ce schéma vaccinal n’est pas toujours respecté, ce qui a pour conséquence qu’une partie de la population n’est plus protégée. Afin de déterminer le statut immunitaire du patient, il est indispensable de pouvoir déterminer le taux d’anticorps. Les immunocapteurs ampérométriques répondent à cet objectif. Plusieurs stratégies d’immobilisation de l’anatoxine tétanique (antigène) sur une SPE ont été mises en œuvre et comparées. L’une d’elles repose sur l’utilisation de microparticules superparamagnétiques pour la réaction immunologique et d’une SPE rendue magnétique par un support aimanté pour la mesure. D’autres reposent sur l’immobilisation de l’antigène et les réactions immunologiques directement à la surface de la SPE. L’utilisation de plans d’expérience, pour l’optimisation des immunoessais sur SPE est également exploitée dans ce travail. Les immunocapteurs développés ont permis de doser les anticorps anti-tetani dans le sérum de cobaye en dessous des valeurs considérées comme protectrices.<p>Dans le second volet, un immunocapteur basé sur l’utilisation de nanobodies® (NB) a été mis au point. Nous avons qualifié ce type d’immunocapteur original de nanoimmunocapteur. Le récepteur de facteur de croissance épidermique humain (HER2) a été utilisé comme cible. La protéine HER2 est considérée comme un biomarqueur important car sa surexpression provoque un type agressif de cancer du sein. Les NB sont des fragments à domaine unique dérivés d'anticorps à chaînes lourdes de camélidés. La stratégie de dosage immunologique en sandwich développée a tiré profit de la petite taille des NB pour la détection du marqueur électroactif d’oxydoréduction. La stabilité élevée des NB immobilisés a permis une durée de stockage des SPE modifiées supérieure à 3 semaines. De très courtes durées d'incubation étaient suffisantes pour obtenir une réponse satisfaisante. Le nanoimmunoessai a permis de déterminer le taux d’HER2 dopé dans des lysats cellulaires.<p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

L’établissement et le maintien du patron d’expression génique sont d’une importance critique pour l’identité cellulaire. Les protéines du groupe Polycomb (PcG) agissent sur la chromatine afin de maintenir la répression génique de ses gènes cibles à travers les cycles cellulaires de façon épigénétique. Toutefois, durant la mitose, la structure de la chromatine est grandement altérée par la répression de la transcription, la condensation de la chromatine et le relâchement de nombreux facteurs de transcription. Une question se pose alors : comment les protéines PcG peuvent-elles maintenir leur fonction à travers la mitose ? En interphase, les protéines PcG sont liées à leurs cibles sur la chromatine. Durant la mitose, la majorité des protéines PcG se libèrent de la chromatine mais une petite fraction persiste. Selon l’hypothèse du mitotic bookmarking, cette fraction agirait comme un ensemble de marqueurs guidant le recrutement des protéines PcG en fin de mitose pour maintenir le profil d’expression génique de la cellule. Cependant, nous ne savons pas comment ce recrutement à lieu, ni comment une fraction de protéines PcG est retenue à la chromatine. Afin de répondre à ces questions, un crible à ARN interférent a été établi pour identifier des facteurs contrôlant la liaison des protéines PcG à la chromatine à travers le cycle cellulaire. Quoiqu’une confirmation soit nécessaire, les facteurs spécifiques à l’interphase sont enrichis en protéines co-purifiant avec la protéine PcG testée et en hélicases alors que ceux spécifiques à la mitose sont enrichis en candidats liés aux protéines du groupe Trithorax (TrxG). / A critical part of cell identity is the establishment and maintenance of gene expression patterns. Polycomb group proteins (PcG) act on chromatin to maintain gene repression through cell cycles (epigenetically). However, during mitosis, chromatin structure is greatly altered by transcription repression, chromatin condensation, and the release of many transcription factors. A question then arises: how can PcG proteins maintain their function through mitosis? During interphase, PcG proteins are bound to their chromatin targets. During mitosis, most PcG proteins are released from chromatin, but a small fraction remains bound to chromatin. According to the mitotic bookmarking hypothesis, this fraction acts as a set of markers to guide the recruitment of PcG proteins at the end of mitosis to maintain the gene expression profile. However, we do not know how this recruitment takes place, nor do we know how a fraction of PcG proteins is retained on chromatin. To address these questions, an RNAi screen was established to identify factors that control the binding of PcG proteins to chromatin across the cell cycle. Although a confirmation is necessary, factors identified from interphase cells were enriched in proteins co-purifying with the tested PcG protein and in helicases while mitosis specific factors were enriched in Trithorax group (TrxG) protein related candidates.

The aim of the presented Diploma Thesis was to develop a new method for the indirect determination of formaldehyde in wood-based products using gas-diffusion microextraction coupled with electrochemical detection on unmodified screen-printed electrodes (MLEM-SPCE). Formaldehyde released from the sample is derivatized using an acetylacetone reagent present in an acceptor solution. The product of derivatization of formaldehyde with acetylacetone is 3,5-diacetyl-1,4-dihydrolutidine (DDL) which forms a selective oxidation voltammetric peak at a potential of 0.4 V. Detection and quantification limits of 0.57 mg kg−1 and 1.89 mg kg−1 , respectively, were obtained, together with intra- and inter-day precision below 10% (as relative standard deviation, RSD). The developed methodology was applied to determine formaldehyde content in seven samples. Similar results were obtained from the European standard method EN 717-3 with a significant reduction of total analysis time. The developed method MLEM-SPCE, which combines the use of a new sample preparation procedure for volatile compounds with the firstly introduced determination of formaldehyde (as the derivative product DDL) on unmodified SPCEs, proves to be a promising alternative for the determination of formaldehyde in wood-based products and other samples.

Background. Maternal obesity and physical inactivity have been identified as correlates of overweight and obesity and physical inactivity in older preadolescents; however, no study has explored this relationship in Hispanic preadolescents. Furthermore, the relation between maternal physical activity (PA) and blood pressure (BP) in Hispanic preadolescents has not been examined. Purpose. This study aimed to assess the associations between Hispanic mothers’ PA and body mass index (BMI) and their preadolescents’ PA, screen time, BP, and BMI. Methods. Data of 118 mother-child (aged 2–10 years) dyads enrolled in a crosssectional study of metabolic syndrome in Hispanic preadolescents at a community health center in Johnson City, TN were used. Parent and child questionnaires were used to ascertain mothers’ BMI and PA and preadolescents’ PA and screen time.

An interactive multiple screen visualisation might become an opportunity for engaging and illustrative presentations of scientific, complex, and abstract research. With multiple (interactive) monitors, storytelling and interfaces could bring engagement, immersion, and attraction to the audience. The challenge of designing for a multiple screen setup is that the amount of information can be overwhelming, causing the perception of it and engagement with it to decrease. This thesis explores approaches that could enhance the perception and engagement of the content for a multiple screen setup. The Research Through Design approach sets the structure for the entire thesis. It consists of methods for exploration, concepting, prototyping, and user testing. By following this research approach, three versions of a prototype were developed and tested which led to the results of this thesis. The overall nature of this research process was exploratory and the design decisions were applied during the activities. The main findings of this thesis regarding the multiple screen setup during the research process included three attention guiding approaches: black and white, blur, and pause, and according to the user test participants, the preferred approach was black and white. The second vital aspect of the research and testing were the five-act story arc and interactive storytelling structures. According to the data from user tests, interactivity helped to increase the engagement and perception of the exhibition piece.

Studien tar avstamp i tidigare undersökningar om textmediers olika effekter och söker att svara på hur elevers läsförståelse påverkas av att läsa texter genom olika textmedium. Studien ville specifikt svara på om elevers inställning till textmediet de använder kan påverka deras läsförståelseförmåga. För att svara på detta användes material från tidigare PISA-undersökningar för att konstruera ett läsförståelsetest som undersökningsgruppen fick göra genom att läsa texter via en skärm eller en vanlig papperstext. Till studien fick undersökningsgruppen även svara på om en enkät där de fick beskriva sina upplevelser av läsning genom olika textmedium. Undersökningsgruppen bestod av sammanlagt 56 elever i årskurs 9. Resultaten visade att elevers inställning till textmediet kan ha påverkan på läsförståelseförmågan, och att elever med en preferens för traditionella papperstexter hade i genomsnitt bättre resultat på läsförståelsetestet. Undersökningens enkät visade att en majoritet av eleverna hade en preferens för papperstext, och att digitala texter generellt upplevdes vara mer obekväm att läsa. / This study uses previous studies about the different effects of text mediums as a starting point and seeks to answer how the reading comprehension of students is affected by reding texts through different textmediums. The study specifically sought to answer whether the reading comprehension of students is affected by their attitude towards the text medium being used. To answer this, the study used material from previous PISA-studies to construct a reading comprehension test which the surveyed group worked with by reading texts either through a screen or a traditional print-based text. The surveyed group also answered a survey where they got to describe their experiences of reading through different textmediums. The group was made up of 56 students in 9th grade. The results showed that students’ attitude towards text mediums may have affected reading comprehension, and that students with a preference for print-based texts had slightly higher average score on the reading comprehension test. The survey showed that a majority of students had a preference for print-based text, and that digital texts was generally considered to be less comfortable as a text medium.

There is an increasing trend of mental health problems both globally and in Sweden. Moreover, in recent decades there has been an increase in screen time among adolescents. The present study aimed to examine the associations between screen time (i.e., smartphone, computer, and TV) and mental health problems among adolescents in Västmanland and to investigate if the association was different due to gender. A quantitative method with a cross-sectional design was applied. The study used secondary data from the Survey of Adolescent Life in Västmanland 2020. The sample consisted of 3880 adolescents from 9th grade in compulsory school and 2nd grade in upper secondary school. The results showed that high screen time on smartphone was associated with an increased probability for mental health problems in the total sample. In contrast, screen time on TV and computer showed no significant association with mental health problems. Thus, smartphone use was a significant contributor to mental health problems. Furthermore, for girls, high screen time on the smartphone, computer, and TV was associated with increased probability of mental health problems, whereas no significant associations were found among boys. In brief, this study’s findings suggest developing Swedish guidelines to regulate harmful effects from screen time.

Objectif. Les avancées technologiques procurent aux jeunes enfants un accès sans précédent aux médias violents. Pourtant, l’étendue et la persistance des risques psychosociaux et scolaires à long terme découlant de l’exposition précoce à des médias violents demeurent méconnues. Cette étude vise donc à examiner les associations prospectives entre l’exposition préscolaire à des contenus télévisuels violents et le bien-être psychosocial des filles et des garçons au début de l’adolescence. Méthode. Les participants (978 filles et 998 garçons) de cette étude longitudinale prospective proviennent de la cohorte de naissances de l'Étude longitudinale du développement des enfants du Québec (ÉLDEQ). Les parents ont rapporté la fréquence d’exposition à des contenus télévisuels violents de leur enfant à l’âge de 3,5 ans et 4,5 ans. Huit ans plus tard, huit indicateurs importants du bien-être psychosocial de l’enfant à 12 ans ont été rapportés par l’enseignant et l’adolescent. Pour mesurer les associations prospectives, les indicateurs de bien-être psychosocial à 12 ans ont d’abord été régressé linéairement sur l’exposition à des contenus télévisuels violents à l’âge de 3,5 et 4,5 ans, et cela, pour chaque enfant, sans distinction du sexe. Puis, des analyses stratifiées par le sexe ont été effectuées. L’ensemble des analyses ont été contrôlées pour des caractéristiques individuelles et familiales confondantes. Résultats. Pour les filles, l’exposition préscolaire à des contenus télévisuels violents est associée à une augmentation de la détresse émotionnelle (β = 0,11; intervalle de confiance [IC] 95 %, 0,13 à 0,49) et à une diminution de l’engagement en classe (β = -0,10; IC 95 %, -1,55 à -0,40), du rendement scolaire (β = -0,16; IC 95 %, -3,48 à -1,72) et de la motivation intrinsèque scolaire (β = -0,07; IC 95 %, -1,09 à -0,07) à l’âge de 12 ans. Pour les garçons, l’exposition préscolaire à des contenus télévisuels violents est associée à une augmentation de la détresse émotionnelle (β = 0,10; IC 95 %, 0,13 à 0,53), de l’inattention (β = 0,08; IC 95 %, 0,06 à 0,45), des comportements découlant du trouble des conduites (β = 0,06; IC 95 %, 0,00 à 0,21) et de retrait social (β = 0,08; IC 95 %, 0,05 à 0,40), ainsi qu’à une diminution de l’engagement en classe (β = -0,07; IC 95 %, -1,57 à -0,12), du rendement scolaire (β = -0,07; IC 95 %, -2,15 à -0,23) et de la motivation intrinsèque scolaire (β = -0,07; IC 95 %, -1,13 à -0,03) à l’âge de 12 ans. Conclusion. Nos résultats révèlent des risques psychosociaux et scolaires distincts et persistants au début de l'adolescence associés à l'exposition préscolaire à des contenus télévisuels violents pour les filles et les garçons. La diminution de l'exposition à des contenus violents à l'écran durant les années préscolaires représente une intervention parentale bénéfique et un objectif d'éducation aux médias. / Objective. The extent to which the long-term risks of early exposure to media violence remains unclear. This study aims to examine whether preschool exposure to violent media predicts a range of associated psycho-social and academic risks for boys and for girls in early adolescence. Methods. Participants (978 girls and 998 boys) are from the Quebec Longitudinal Study of Child Development birth cohort. Self- and teacher-reported measures of child psycho-social and academic adjustment indicators at age 12 years were linearly regressed on parent-reported child exposure to televised violence at age 3.5 and 4.5 years, while adjusting for potential confounders. Results. For girls, violent televiewing during preschool years was associated with increases in emotional distress (β = 0.11; 95% confidence interval [CI], 0.13 to 0.49) and decreases in classroom engagement (β = -0.10; 95% CI, -1.55 to -0.40), academic achievement (β = -0.16; 95% CI, -3.48 to -1.72), and intrinsic academic motivation (β = -0.07; 95% CI, -1.09 to -0.07) at age 12 years. For boys, violent televiewing during preschool years was associated with increases in emotional distress (β = 0.10; 95% CI, 0.13 to 0.53), inattention (β = 0.08; 95% CI, 0.06 to 0.45), and conduct disordered (β = 0.06; 95% CI, 0.00 to 0.21) and socially withdrawn behavior (β = 0.08; 95% CI, 0.05 to 0.40), as well as decreases in classroom engagement (β = -0.07; 95% CI, -1.57 to -0.12), academic achievement (β = -0.07; 95% CI, -2.15 to -0.23) and intrinsic academic motivation (β = -0.07; 95% CI, -1.13 to -0.03) at age 12 years. Conclusion. Our findings in early adolescence reveal distinct, persistent risks associated with preschool exposure to violent televiewing for boys and girls. Diminishing preschool screen violence exposure represents a useful parent intervention and media literacy target.

Biological tubes possessing a curvilinear form and a hollow interior exist in most multicellular eukaryotes. In Eumetazoa, the tubes usually comprise an eminently complex network and enable the transport and exchange of fluids and gases between tissues and organs, but also between organisms and their environment. Thus, tubular structures are both morphologically and physiologically integral parts of the animals. Based on a genetic screen for novel factors involved in heart tube differentiation and morphogenesis in Drosophila, the identified mutants were subdivided into several classes: cardiac hyperplasia (kuz and mam, both involved in the Notch-dependent cardiomyocyte specification, Publication 1); impaired cytokinesis (pav and tum, both components of the centralspindlin complex); a single ptc mutant showing a “truncated” heart (Publication 2); and a single loss-of-function mutant displaying reduced lumen diameter in epithelial tubes and perturbed secretion of ECM-components. The latter allele was mapped to the gene locus gartenzwerg (garz) that encodes a large ArfGEF. Due to its novelty, garz was selected as a central part of the thesis (Publication 3). Although garz seems to be expressed ubiquitously, its transcripts are abundant in active secreting cells of tubular structures. Moreover, mutations of garz abolish Golgi-integrity, cause massive retention of secretory cargo in the ER and arrest the apical transport of lipids and ECM molecules. As a consequence, lumen of the salivary glands and trachea fail to expand and show a decreased diameter. The observed phenotypes in tracheal network and salivary glands phenocopy those of COPI/COPII-subunits as well as actin-dependent secretion mutants, suggesting the underlying mechanism might be common. Thus, it is supposed that proper tubulogenesis needs Garz for initiation of the Arf1-COPI machinery. Furthermore, Golgi-based post-translational modifications, targeted sorting of vesicles, outward transport of proteins, or directed membrane delivery all depend on the secretory pathway, and such processes are essential in establishing polarized cells which build the tubular structures. In conclusion, this mechanism seems to be neither restricted to tubulogenesis nor specific to Drosophila. Due to the presence of garz homologues in every eukaryotic genomes, the Arf1/COPI based secretory pathway may play a universal role in metazoan development.

Syftet med denna studie var att undersöka samband mellan stress, sömn och skärmtid på smarttelefon. Urvalet bestod av totalt 81 personer på ett universitet i södra Sverige. Två hypoteser testades. 1: hög grad av faktisk skärmtid är relaterat till en hög subjektiv stressupplevelse och hög grad av sömnbesvär. 2: Låg grad av stress är associerat med låg grad av sömnbesvär. Vid insamlingen av data användes, Perceived stress scale 10 (PSS-10) och Karolinska sleep questionnaire (KSQ). För att mäta skärmtid designades två frågor, en med syfte att mäta individers subjektiva upplevelse av mängden skärmtid och en för att mäta den faktiska mängden som kan utläsas via en funktion på individers smarttelefon. Resultatet för hypotes 1 visade att faktisk skärmtid varken samvarierade med stress eller sömnbesvär. Vidare jämfördes också gruppen hög faktisk skärmtid som översteg 29 h/vecka med stress och sömnbesvär. Resultatet indikerade att en hög faktisk skärmtid och stress inte korrelerade och hög faktisk skärmtid och sömnbesvär inte korrelerade. Resultatet för hypotes 2 visade en negativ signifikant korrelation mellan variablerna stress och sömnbesvär. Det innebar att höga värden på total KSQ, mindre sömnbesvär, korrelerar med låga värden på PSS-10, låg nivå av upplevd stress. Sammanfattningsvis visade studiens resultat att faktisk skärmtid inte samvarierade med varken stress eller sömnbesvär. Dock återfanns en korrelation mellan variablerna stress och sömnbesvär. / The purpose of this study was to investigate the relationship between stress, sleep and screen time on smartphones. The sample consisted of a total of 81 people at a university in southern Sweden. Two hypotheses were tested. 1: High degree of actual screen time is related to a high subjective stress experience and high degree of sleep disturbance. 2: Low levels of stress are associated with low levels of sleep disturbance. In the data collection, Perceived stress scale 10 (PSS-10) and Karolinska sleep questionnaire (KSQ) were used. To measure screen time, two questions were designed, one aimed at measuring individual's subjective experience of the amount of screen time and one to measure the actual amount that can be read through a function on an individual's smartphone. The result for Hypothesis 1 showed that actual screen time did not co-vary with stress or sleep disturbance. Furthermore, the group, high actual screen time exceeding 29 h / week was also compared with the variables stress and sleep disturbance. The result indicated that a high actual screen time and stress did not correlate, and high actual screen time and sleep disturbances did not correlate either. The result for Hypothesis 2 showed a negatively significant correlation between the variables stress and sleep disorders. This meant that high values of total KSQ, less sleep disturbances, correlated with low values of PSS-10, low levels of stress. In summary, the study's results showed that actual screen time did not correlate with neither stress nor sleep disturbance. However, a correlation was found between the variables stress and sleep disturbance.