Thesis (M.S.)--West Virginia University, 2002. / AH26 is a registered trademark. Title from document title page. Document formatted into pages; contains vii, 55 p. : ill. (some col.). Includes a video file in the AVI format. Vita. Includes abstract. Includes bibliographical references (p. 48-53).

Thesis (M.S. )--University of Tennessee Health Science Center, 2007 / Title from title page screen (viewed on June 10, 2008). Research advisor: Edward F. Harris, PhD Document formatted into pages (xii,163 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 109-125).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vii, 38 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 27-30).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains vii, 47 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 35-38).

Dans l’optique d’une seconde Révolution Verte, visant, à la différence de la première, à accroître les rendements des cultures dans un contexte de faible fertilité, les stratégies mises en place par les plantes pour une assimilation optimale des nutriments du sol se trouvent au cœur du problème. Afin de le résoudre et d’identifier les variétés idéales parmi la diversité génétique des plantes cultivées, les systèmes racinaires, leur développement et leur architecture, sont appelés à jouer le premier rôle. La variabilité au sein des racines latérales semble s’avérer une caractéristique cruciale pour l’optimisation de l’exploration du sol et de l’acquisition de ses ressources mobiles et immobiles, mais ce phénomène est encore mal appréhendé.Le travail présenté dans cette thèse se concentre sur les racines latérales du maïs (Zea mays L.) dans un effort pour révéler les processus à l’origine des variations intrinsèques dans le développement racinaire. Il s’appuie en particulier sur le phénotypage des racines latérales à une échelle sans précédent, suivant la croissance journalière de milliers d’entre elles à haute résolution spatiale, pour caractériser précisément les variations spatio-temporelles entre et au sein des individus racinaires. Les profils individuels de vitesse de croissance ont été analysés à l’aide d’un modèle statistique qui a identifié trois principales tendances temporelles dans les vitesses de croissance menant à la définition de trois classes de racines latérales avec une vitesse et durée de croissance distinctes. Des différences de diamètre à l’émergence de ces racines (dont l’origine remonte au stade du primordium) conditionnent probablement la tendance ultérieur de croissance mais ne suffisent pas à déterminer le destin de la racine. Finalement, ces classes racinaires sont distribuées aléatoirement le long de la racine primaire, ce qui suggère qu’aucune stimulation ou inhibition locale n’existe entre racines voisines.Pour expliquer l’origine des variations observées dans la croissance, ce travail a été complété par une caractérisation multi-échelle de groupes de racines latérales présentant une croissance distincte, à un niveau cellulaire, anatomique et moléculaire. Un effort particulier a été dirigé à l’analyse des profils de longueur de cellules dans des apex racinaires pour lequel nous avons introduit un modèle de segmentation pour identifier des zones développementales. Grâce à cette méthode, une forte modulation dans la longueur des zones de division et d’élongation a été mise en évidence, en lien avec les variations de la croissance des racines latérales. Le rôle régulateur de l’auxine sur l'équilibre entre les processus de prolifération et d’élongation cellulaire a été montré avec l’utilisation de lignées mutantes. En fin de compte, les variations de la croissance entre racines latérales sont remontées jusqu’à l’allocation d’assimilats carbonés et la capacité de transport de la racine, ce qui suggère l’existence d’un mécanisme de rétroaction qui pourrait jouer un rôle déterminant dans la mise en place de tendances contrastées dans la croissance des racines latérales. / In the perspective of a second Green Revolution, aiming, unlike the first one, to enhance yields of crops in a low fertility context, the strategies used by plants for an optimal uptake of soil nutrients are at the core of the problem. To solve it and identify ideal breeds among the genetic diversity of crops, plant root systems, their development and their architecture, are called upon to play the leading role. The variability among secondary roots appears as a crucial feature for the optimality of soil exploration and acquisition of mobile and immobile resources, but this phenomenon remains poorly understood. The work presented in this thesis focuses on the lateral roots of maize (Zea mays L.) and attempts to unravel the processes at the origin of intrinsic variations in lateral root development. It relies notably on the phenotyping of individual lateral roots at an unprecedented scale, tracking the daily growth of thousands of them at a high spatial resolution, in order to characterize precisely the spatio-temporal variations existing both between and within root individuals. Individual growth rate profiles were analyzed with a statistical model that identified three main temporal trends in growth rates leading to the definition of three lateral root classes with contrasted growth rates and growth duration. Differences in lateral root diameter at root emergence (originating at the primordium stage) were likely to condition the followed growth trend but did not seem enough to entirely determine lateral root fate. Lastly, these lateral root classes were randomly distributed along the primary root, suggesting that there is no local inhibition or stimulation between neighbouring lateral roots. In order to explain the origin of the observed differences in growth behaviour, we complemented our study with a multi-scale characterization of groups of lateral roots with contrasted growth at a cellular, anatomical and molecular level. A particular focus is set on the analysis of cell length profiles in lateral root apices for which we introduced a segmentation model to identify developmental zones. Using this method, we evidenced strong modulations in the length of the division and elongation zones that could be closely related to variations in lateral root growth. The regulatory role of auxin on the balance between cellular proliferation and elongation processes is demonstrated through the analysis of mutant lines. Ultimately, variations in lateral root growth are traced back to the allocation of carbon assimilates and the transport capacity of the root, suggesting that a feedback control loop mechanism could play a determinant role in the setting out of contrasted lateral root growth trends.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: One of the challenges of non-surgical root canal treatment (NSRCT) is determining the working length of the canal which indicates the exact end point of root canal preparation and obturation. The development of the Electronic Apex Locator (EAL) has helped the clinician to determine the location of the apical foramen, and hence the working length, when performing NSRCT. Objective: The objective of this in vitro study was to determine the accuracy of a new EAL, the E-PEX (Changzhou Eighteeth Medical Technology Co., China), and compare it to a commonly used EAL, the Root ZX II (J. Morita Corp, Kyoto, Japan), for determining the location of the apical foramen. Materials and Methods: Twenty extracted single rooted teeth were used in this study. The crowns were removed and the distance from a coronal reference point to the apical foramen was measured utilizing a k-file and direct visualization under magnification. Teeth were then mounted in alginate and measurements for the apical foramen were made using the Root ZX II and the E-PEX. The difference between the actual canal length and the electronic length was then calculated and compared. Results: The mean true difference was -0.20, and -0.19 for the E-PEX and Root ZX II respectively. The mean absolute difference was 0.28, and 0.26 for the E-PEX and Root ZX II respectively. Paired t-tests done separately for true differences (p = 0.45) and absolute differences (p = 0.21) showed no significant difference among EALs. The percentage of measurements falling within 0.5 mm of the actual canal lengths for each EAL were 95% and 90% for the E-PEX and Root ZX II respectively. McNemar’s test was used to compare between the two test methods for the percentage within 0.5 mm and revealed no significant difference (p = 0.32). Conclusion: The Root ZX II had an average measurement that was slightly closer to the actual length of the canal when compared to the E-PEX, while the E-PEX had a higher percentage of measurement within 0.5 mm of the apical foramen. However, these differences were not statistically significant.

published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / Paediatric Dentistry / Master / Master of Dental Surgery

No description available.

4 pp. / Cotton root rot commonly causes a sudden wilt and death of susceptible plants in summer months but may also cause a slow decline, especially at cooler temperatures. So, positive identification of disease by an experienced person is essential. This publication addresses the symptoms, environmental conditions, disease, prevention and control methods, sampling, identifying susceptible plants and the tolerant and immune plants of cotton root rot.