The U.S. is the largest maize producer in the world with a production of 300 million tons in 2012. Approximately 86% of the maize production is focused on the Midwestern states. The rest of the production is focused in the Southern states, where Texas is the largest maize producer. Grain yield in Texas ranges from 18 tons/ha in the irrigated production zones to 3 tons/ha in the dryland production zones. As a result, grain yield has increased slowly because of the poor production in the non-irrigated acres. Methods to improve the grain yield in Texas is to breed for maize varieties adapted to Texas growing conditions, including mapping genes that can be incorporated into germplasm through marker assisted selection. This dissertation includes two separate projects that exploit historical data and maize diversity to increase grain yield in Texas. For the first project, a large dataset collected by Texas AgriLife program was analyzed to elucidate past trends and future hints on how to improve maize yield within Texas. This study confirmed previous reports that the rate of increase for grain yield in Texas is less than the rate observed in the Midwestern US. For the second project, a candidate gene and whole genome association mapping analysis was performed for drought and aflatoxin resistance in maize. In order to do so, maize inbred lines from a diversity panel were testcrossed to isogenic versions of Tx714. The hybrids were evaluated under irrigated and non-irrigated conditions. The irrigated trials were inoculated with Aspergillus flavus and the aflatoxin level was quantified. This study found that the gene ZmLOX4 was associated with days to silk, and the gene ZmLOX5 gene was associated with plant and ear height. In addition, this study identified 13 QTL variants for grain yield, plant height, days to anthesis and days to silk. Furthermore, this study shows that diverse maize inbred lines can make hybrids that out yield commercial hybrids under heat and drought stress. Therefore, there are useful genes present in these diverse lines that can be exploited in maize breeding programs

Androgens are the main regulators of human hair growth stimulating larger, terminal hair development e.g. beard and causing scalp balding, androgenetic alopecia. Hair disorders cause psychological distress but are poorly controlled. Androgens probably act by altering regulatory paracrine factors produced by the mesenchyme-derived dermal papilla. This study aimed to investigate paracrine factors involved in androgen-regulated alopecia, particularly hepatocyte growth factor (HGF) family members, by investigating their in vivo status. Balding and non-balding scalp hair follicles and their component tissues were isolated and analysed by molecular biological methods (reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative PCR and DNA microarray analysis), cell culture and immunohistochemistry. Scalp follicles expressed a range of paracrine messenger genes. The dermal papilla, cultured dermal papilla cells and dermal sheath expressed several HGF family genes, while matrix cells only produced the receptor RON suggesting autocrine roles for HGF and MSP, but a paracrine route only for MSP. Comparing balding and non-balding follicles from the same individuals revealed the expected reduction in several keratin and keratin-related protein genes supporting this approach's validity. There were also significant differences in paracrine factors previously implicated in androgen action by in vitro studies. Several factors believed to increase during androgen stimulation of larger, darker follicles, e.g. IGF-I and SCF, were lowered in balding follicles, while putative inhibitory factors, e.g. TGFß-1, were increased. HGF and MSP and their receptors, c-Met and RON, were significantly reduced. These results increase our understanding of androgen action in human hair follicles; this could lead to better treatments for hair disorders.

Les conduites primaires des centrales nucléaires REP (304L et 316L) sont protégées contre la corrosion par une couche d'oxyde. Ces conduites, qui forment une barrière entre le milieu primaire et l'extérieur, subissent des phénomènes liés à la corrosion sous contrainte (assisté ou non par irradiation) pouvant entrainer des dommages. L'objectif de cette étude est de comprendre les phénomènes régissant les stades initiaux de formation des couches d'oxydes sur ces alliages en tenant compte de l'orientation cristallographique des grains sous-jacents. En utilisant des techniques de caractérisation avancées comme GIXRD, spectroscopie Raman, XPS, MEB et MET (BF, HRTEM, Astar, EELS et HREELS), sur les toutes premières étapes de l'oxydation, une séquence d'oxydation a été proposée pour l'alliage 316L.

Sammanfattning Syfte och frågeställningar Syftet med den här studien var att undersöka självrapporterad fysisk aktivitet och stillasittande hos personer med olika aktivitetsnivå på arbetet.     Skiljer sig den fysiska aktiviteten i olika domäner (transport, hem och fritid) respektive den totala fysiska aktiviteten utöver arbetet beroende på aktivitetsnivå på arbetet? Skiljer sig tiden stillasittande beroende på aktivitetsnivå på arbetet? Metod För att uppfylla syftet valdes en kvantitativ metod med tvärsnittsdesign. Data samlades in med hjälp av enkäten International Physical Activity Questionnaire (lång version), där frågorna om fysisk aktivitet är uppdelade i fyra domäner; arbete, transport, hem och fritid och berör intensitet, frekvens och duration. Frågorna om stillasittande är uppdelade för vardag och helg. Urvalet bestod av personer som arbetade heltid och flera olika yrken inkluderades i studien. Undersökningsdeltagarna delades in i tre grupper efter aktivitetsnivå på arbetet och jämfördes med avseende på fysisk aktivitet utanför arbetet respektive stillasittande. Fysisk aktivitet i varje domän och total fysisk aktivitet utanför arbetet redovisades i MET-minuter/vecka. Stillasittande angavs i minuter och presenterades för fem vardagar respektive en vecka. Resultat Totalt deltog 196 personer i studien. Fritiden var den största källan till den totala fysiska aktiviteten utanför arbetet i alla grupper (minst 63 % av tiden) och aktiviteten vid både transport och i hemmet var relativt låg. En signifikant skillnad mellan grupperna sågs för fysisk aktivitet i arenan hem, där personer med ett högaktivt arbete rörde på sig mer i hemmet (median: 360 MET-minuter/vecka) jämfört med personer med ett lågaktivt arbete (90 MET-minuter/vecka). I domänerna transport och fritid skiljde sig mängden fysisk aktivitet något mellan grupperna, men inte signifikant. För tid stillasittande sågs en signifikant skillnad mellan grupperna, både under fem vardagar och under en vecka. Personer med ett högaktivt arbete satt mindre (900 minuter respektive 1 380 minuter) än de som hade ett lågaktivt arbete (2 100 minuter respektive 2 640 minuter).    Slutsats Studien visade att den största delen utförd fysisk aktivitet utanför arbetet inte verkar bero på aktivitetsnivån på arbetet. Det var endast för den fysiska aktiviteten i hemmet som det sågs en signifikant skillnad mellan olika aktivitetsnivåer på arbetet. Vid transport och fritid sågs små skillnader i fysisk aktivitet, men dessa var inte signifikanta. För den totala tiden stillasittande däremot verkar graden av fysisk aktivitet på arbetet ha betydelse. Ett lågaktivt arbete gav längre total tid stillasittande jämfört med ett högaktivt arbete. Fysisk aktivitet och stillasittande bör som enskilda beteenden ses över både på arbetsplatsen och i domänerna utanför arbetet. Vidare bör också undersökas vilka andra faktorer som kan påverka dessa två beteenden.

Les systèmes barrières thermiques (BT), utilisés dans les turbines aéronautiques, sont des systèmes multicouches composés d'un substrat en superalliage monocristallin, d'une sous-couche d'alliage alumino-formeur sur laquelle se forme une couche d'alumine, initiée pendant le procédé de fabrication. Le tout est revêtu d'une couche en zircone, la barrière thermique, qui permet de diminuer la température de travail du substrat. Cette couche, perméable à l'oxygène, conduit au développement de l'oxyde tout au long de la vie du système. Les systèmes BT sont soumis à des contraintes thermomécaniques qui créent des endommagements, en particulier aux interfaces, pouvant mener à l'écaillage de la BT. Ces endommagements dépendent de la composition et de la microstructure des différents constituants du système. L'objectif de cette thèse est de corréler les évolutions microstructurales dans la sous-couche et dans l'oxyde à l'adhérence des systèmes BT. Pour ce faire, le vieillissement de systèmes de superalliages AM1 et MCNG revêtus d'une sous-couche NiAlPt, avec et sans barrière thermique, a été suivi sous sollicitations isothermes et cycliques à 1100°C. L'effet d'une étape de pré-oxydation sur la durée de vie à long terme après oxydation isotherme de ces systèmes a été étudié pour différents états de surface initiaux. Ce travail a permis de confirmer l'effet du type de sollicitation et de la présence de la BT sur les mécanismes d'endommagement et de mettre en évidence la meilleure résistance à l'écaillage des systèmes MCNG comparés aux systèmes AM1. Il a également montré que la formation d'alumine de transition au cours des premiers stades d'oxydation ne semblait pas néfaste pour l'adhérence du système. Enfin, la détection et la localisation par SIMS d'impuretés telles que le soufre et le carbone et d'éléments réactifs tels que le hafnium ont révélé le rôle prépondérant joué par ces éléments sur la durée de vie des systèmes BT.

Neutral gas-phase metal-carbide clusters are generated by laser ablation and are detected in the constructed time-of-flight mass-spectrometer by laser ionisation. Photo-ionisation efficiency (PIE) experiments are performed on the metal-carbide clusters to determine their ionisation potentials (IPs). Complimentary density functional theory (DFT) calculations are performed on the energetically favorable structural isomers of the metalcarbide clusters. Comparison between the calculated IPs of the isomers and the experimental IP allows the carrier of the observed ionisation onset for a metal-carbide cluster to be assigned. The niobium-carbide clusters Nb₃Cy (y = 0–4), Nb₄Cy (y = 0–6) and Nb₅Cy (y = 0–6) are examined by PIE experiments and DFT calculations. The IPs of the niobium-carbide clusters are found to be either left reasonably unchanged from the IPs of the bare metal clusters or moderately reduced. The clusters Nb₃C₂, Nb₄C₄, Nb₅C₂ and Nb₅C₃ display the largest IP reductions for their corresponding cluster series. The structures assigned to the IPs of the Nb₃Cy (y = 1–3) clusters are based on the carbon atoms attaching to the niobium faces and/or niobium-niobium edges of the triangular Nb₃ cluster. However, for Nb₃C₄ the ionisation onset is assigned to a low-lying isomer, which contains a molecular C₂ unit, rather than the lowest energy isomer, a niobium atom deficient 2×2×2 face-centred cubic (fcc) nanocrystal structure. The structures assigned to the IPs of the Nb₄Cy (y = 1–4) clusters are based on the carbon atoms attaching in turn to the niobium faces of the tetrahedral Nb₄ cluster, developing a 2×2×2 fcc nanocrystal structure for Nb₄C₄. For Nb₄C₃ two ionisation onsets are observed; one weak onset at low energy and another more intense onset at high energy. It is proposed that the two onsets are due to ionisation from both a metastable ³A₁ state and the ground ¹A₁ state of the lowest energy isomer. The ionisation onsets of Nb₄C₅ and Nb₄C₆ are also proposed to originate from metastable triplet states of the lowest energy isomers, with the transitions from the ground singlet states calculated to be greater than the highest achievable photon energy in the laboratory. The structures of Nb₄C₅ and Nb₄C₆ have one and two carbon atoms in a 2×2×2 fcc nanocrystal substituted with molecular C₂ units, respectively. The structures assigned to the IPs of the Nb₅Cy (y = 1–6) clusters are based on the underlying Nb₅ cluster being in either a “prolate” or “oblate” trigonal bipyramid geometry; the former has six niobium faces available for carbon addition, while the latter has two niobium butterfly motifs and two niobium faces available for carbon addition. Both the structures of Nb₅C₅ and Nb₅C₆ have the underlying Nb₅ cluster in the oblate trigonal bipyramid geometry and contain one and two molecular C₂ units, respectively. The tantalum-carbide clusters Ta₃Cy (y = 0–3), Ta₄Cy (y = 0–4) and Ta₅Cy (y = 0–6) are examined by PIE experiments and DFT calculations. The IPs of the tantalum-carbide clusters in each series show trends that are very similar to the corresponding iso-valent niobium-carbide cluster series, although the IP reductions upon carbon addition are smaller for the former. For the vast majority of tantalum-carbide clusters, the same structural isomer is assigned to the ionisation onset as that assigned for the corresponding niobium-carbide cluster. Bimetallic tantalum-zirconium-carbide clusters are generated using a constructed double ablation cluster source. The Ta₃ZrCy (y = 0–4) clusters are examined by PIE experiments and DFT calculations. The IP trend for the Ta₃ZrCy cluster series is reasonably similar to that of the Ta₄Cy cluster series, although the IP reductions upon carbon addition are greater for the former. The structures assigned to the IPs of the Ta₃ZrCy (y = 1–4) clusters are based on the carbon atoms attaching in turn to the metal faces of the tetrahedral Ta₃Zr cluster. In summary, the work presented in this thesis demonstrates that the structures of metalcarbide clusters can be inferred by the determination of their IPs through PIE experiments in combination with DFT calculations on candidate structural isomers. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347219 / Thesis (Ph.D.) - University of Adelaide, School of Chemistry and Physics, 2008

This work investigates the interactions of carbonaceous materials (metallurgical coke, natural graphite and HDPE/coke blends) with three EAF slags [FeO: 24% to 32%]. Experiments were conducted using the sessile drop technique (1500??C-1600??C) with off-gases (CO, CO2) measured using an IR analyzer; the wetting behaviour was determined from contact angle measurements. Estimation of slag foaming behaviour was determined from the droplet volume changes calculated using specialized software. At 1550??C, all slags were non-wetting with coke due to increased surface tension due to sulphur. At 1550??C, slag 1 was initially non-wetting on natural graphite due to gas entrapment in the slag droplet; the wetting improved after that. Other slags showed comparatively better wetting. At 1600??C, all slags were non-wetting with coke. Slags showed a shift from non-wetting to wetting behaviour with natural graphite. Slag/coke reactions produced high off-gases levels causing extensive FeO reduction; gas entrapment in the slag was poor (small volume droplets). Slag/natural graphite interactions revealed both slow gas generation rates and FeO reduction, and excellent gas entrapment (higher droplet volumes) with minor changes in slag properties due to low ash levels. The iron oxide reduction rates were determined to be 1.54x10-5 and 4.2x10-6 mol.cm-2/sec (Slag 1, 1550??C) for metallurgical coke and natural graphite respectively. Slag interactions with coke/HDPE blends showed increasing off-gas levels with increasing HDPE levels. Blend#3 produced the highest off-gas levels, extensive FeO reduction and displayed significantly higher slag foaming and better wetting compared to coke. Our line on trends compared well for slag/carbon interactions and resulted in deceased specific energy consumption and carbon usage and increased productivity. These findings have enhanced the possibility of utilizing polymeric wastes in blends with coke in EAF steelmaking for slag/carbon interactions.

Neutral gas-phase metal-carbide clusters are generated by laser ablation and are detected in the constructed time-of-flight mass-spectrometer by laser ionisation. Photo-ionisation efficiency (PIE) experiments are performed on the metal-carbide clusters to determine their ionisation potentials (IPs). Complimentary density functional theory (DFT) calculations are performed on the energetically favorable structural isomers of the metalcarbide clusters. Comparison between the calculated IPs of the isomers and the experimental IP allows the carrier of the observed ionisation onset for a metal-carbide cluster to be assigned. The niobium-carbide clusters Nb₃Cy (y = 0–4), Nb₄Cy (y = 0–6) and Nb₅Cy (y = 0–6) are examined by PIE experiments and DFT calculations. The IPs of the niobium-carbide clusters are found to be either left reasonably unchanged from the IPs of the bare metal clusters or moderately reduced. The clusters Nb₃C₂, Nb₄C₄, Nb₅C₂ and Nb₅C₃ display the largest IP reductions for their corresponding cluster series. The structures assigned to the IPs of the Nb₃Cy (y = 1–3) clusters are based on the carbon atoms attaching to the niobium faces and/or niobium-niobium edges of the triangular Nb₃ cluster. However, for Nb₃C₄ the ionisation onset is assigned to a low-lying isomer, which contains a molecular C₂ unit, rather than the lowest energy isomer, a niobium atom deficient 2×2×2 face-centred cubic (fcc) nanocrystal structure. The structures assigned to the IPs of the Nb₄Cy (y = 1–4) clusters are based on the carbon atoms attaching in turn to the niobium faces of the tetrahedral Nb₄ cluster, developing a 2×2×2 fcc nanocrystal structure for Nb₄C₄. For Nb₄C₃ two ionisation onsets are observed; one weak onset at low energy and another more intense onset at high energy. It is proposed that the two onsets are due to ionisation from both a metastable ³A₁ state and the ground ¹A₁ state of the lowest energy isomer. The ionisation onsets of Nb₄C₅ and Nb₄C₆ are also proposed to originate from metastable triplet states of the lowest energy isomers, with the transitions from the ground singlet states calculated to be greater than the highest achievable photon energy in the laboratory. The structures of Nb₄C₅ and Nb₄C₆ have one and two carbon atoms in a 2×2×2 fcc nanocrystal substituted with molecular C₂ units, respectively. The structures assigned to the IPs of the Nb₅Cy (y = 1–6) clusters are based on the underlying Nb₅ cluster being in either a “prolate” or “oblate” trigonal bipyramid geometry; the former has six niobium faces available for carbon addition, while the latter has two niobium butterfly motifs and two niobium faces available for carbon addition. Both the structures of Nb₅C₅ and Nb₅C₆ have the underlying Nb₅ cluster in the oblate trigonal bipyramid geometry and contain one and two molecular C₂ units, respectively. The tantalum-carbide clusters Ta₃Cy (y = 0–3), Ta₄Cy (y = 0–4) and Ta₅Cy (y = 0–6) are examined by PIE experiments and DFT calculations. The IPs of the tantalum-carbide clusters in each series show trends that are very similar to the corresponding iso-valent niobium-carbide cluster series, although the IP reductions upon carbon addition are smaller for the former. For the vast majority of tantalum-carbide clusters, the same structural isomer is assigned to the ionisation onset as that assigned for the corresponding niobium-carbide cluster. Bimetallic tantalum-zirconium-carbide clusters are generated using a constructed double ablation cluster source. The Ta₃ZrCy (y = 0–4) clusters are examined by PIE experiments and DFT calculations. The IP trend for the Ta₃ZrCy cluster series is reasonably similar to that of the Ta₄Cy cluster series, although the IP reductions upon carbon addition are greater for the former. The structures assigned to the IPs of the Ta₃ZrCy (y = 1–4) clusters are based on the carbon atoms attaching in turn to the metal faces of the tetrahedral Ta₃Zr cluster. In summary, the work presented in this thesis demonstrates that the structures of metalcarbide clusters can be inferred by the determination of their IPs through PIE experiments in combination with DFT calculations on candidate structural isomers. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347219 / Thesis (Ph.D.) - University of Adelaide, School of Chemistry and Physics, 2008

Proefschrift Maastricht. / Lit. opg. - Met samenvatting in het Nederlands.

Thesis (Ph.D. in Cell Biology, Stem Cells, and Development) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 102-114). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;