We prepared a seties of tridentate amido diphosphine ligands, including symmetrical [N(o-C6H4PR2)2]- ([R-PNP]- ; R = Ph, iPr, Cy) and unsymmetrical [N(o-C6H4PPh2) (o-C6H4PiPr2)]-. Deprotonation of neutral ligands, H[R-PNP] ( R = Ph, iPr, Cy) or H[Ph-PNP-iPr], with n-BuLi in ether solutions at -35oC produced the lithium complexes, [R-PNP]Li(solv)n ( R = Ph, iPr, Cy; solv = THF, OEt2; n = 1,2) or [Ph-PNP-iPr]Li(solv)n (solv = THF, OEt2; n = 1,2), respectively. The reactions of the lithium complexes or neutral ligands with NiCl2(DME) in THF solutions generated nickel(II) chloride complexes, [R-PNP]NiCl ( R = Ph, iPr, Cy) or [Ph-PNP-iPr]NiCl, which was then reacted with a variety of Grignard reagents to afford the corresponding hydrocarbyl complexes. Of particular interest among the compounds isolated are alkyl complexes that contain £]−hydrogen atoms. The metathetical reactions of nickel(II) chloride complexes with LiNHPh, NaOPh, NaSPh, or NaOtBu, respectively, produced the correspounding nickel anilide, nickel phenolate, nickel thiophenolate and nickel tert-butoxide derivatives. Protonolysis studies of nickel(II)-heteroatom complexes revealed the basic reactivity of these £k-donor ligands. The basicity follows the order OtBu > NHPh > OPh > SPh. Treatment of Ni(COD)2 (COD = cycloocta-1,5-diene) with neutral ligands produced the correspounding four-corrdinate nickel hydride complexes, [R-PNP]NiH (R = Ph, iPr, Cy) or [Ph-PNP-iPr]NiH. The olefin insertion reactions of [iPr-PNP]NiH or [Ph-PNP-iPr]NiH with ethylene, 1-hexene, and norbornene, respectively, generated the corresponding ethyl, n-hexyl, and 2-norbornyl complexes. The formation of [iPr-PNP]Ni(n-hexyl) or [Ph-PNP-iPr]Ni(n-hexyl) is indicative of exclusive 1,2-insertion of 1-hexene. In contrast, styrene inserts into the Ni-H bond of [Ph-PNP-iPr]NiH in an exclusively 2,1-manner to afford [Ph-PNP-iPr]NiCH(Me)Ph. The selective 2,1-insertion products [R-PNP]NiCH(Me)CO2Me (R = Ph, iPr, Cy) or [Ph-PNP-iPr]NiCH(Me)CO2Me were also isolated from the reactions of methyl acrylate with the corresponding nickel hydride complexes. The effects of the phosphorus and olefin substituent on the reactivity and regioselectivity of the olefin insertion reactions are discussed. We also prepared nickel acyl complexes and nickel complexes catalyzed C-N bond formation. In addition to solution NMR spectroscopic data for all new compounds. X-ray diffraction revealed solid structures. A series of five-coordinate aluminum complexes supported by o-phenylene - derived amido diphosphine ligands have been prepared and structurally characterized. Alkane elimination reactions of trialkylaluminum with neutral ligands, H[R-PNP] ( R = Ph, iPr) and H[Ph-PNP-iPr] in toluene solution at -35oC respectively produced the corresponding dialkyl complexes [iPr-PNP]AlR'2, [Ph-PNP]AlR'2 and [iPr-PNP-Ph]AlR'2 (R' = Me, Et, iBu) in high isolated yield. The dihydride complexes [iPr-PNP] AlH2, [Ph-PNP]AlH2 and [iPr-PNP-Ph]AlH2 prepared in one-pot reactions of in situ prepared dichloride precursors with LiAlH4 in THF at room temperature. X-ray diffraction studies revealed a distorted trigonal-bipyramidal structure for these molecules in which the two phosphorus donors are mutually trans. The solution structures of these complexes were all characterized by 1H, 13C, and 31P NMR spectroscopy. The NMR data are indicative of solution C2 symmetry for [iPr-PNP]- and [Ph-PNP]- complexes, whereas they are indicative of C1 for [iPr-PNP-Ph]- derivatives. The 1H NMR spectra of [iPr-PNP]AlR'2, [Ph-PNP]AlR'2 and [iPr-PNP-Ph]AlR'2 (R' = Et, iBu) revealed diastereotopy for the £\-hydrogen atoms in these molecules.

Thesis (Ph. D.)--School of Chemistry and Biochemistry, Georgia Institute of Technology, 2004. Directed by Charles L. Liotts. / Includes bibliographical references.

Thesis (doctoral)--University of Lund.

No description available.

The live export of cattle is an important industry for Australia. Concerns have arisen about animal welfare and in particular heat stress which may cause production losses and death. Cattle shipped live to the Middle East from a southern Australian winter can face continuous and prolonged periods of high heat and humidity as they cross the equator and arrive into a northern hemisphere summer, leading to heat stress and excessive heat load. Some live animal exporters treat heat stressed cattle with electrolyte supplements, but no scientific data exists as to whether this is beneficial to cattle in these unique environmental conditions. In response to industry’s concerns, the experiments described here monitored the physiological responses of Bos taurus and Bos indicus to conditions similar to those experienced by cattle being shipped from southern Australian to the Middle East. Initial experiments were conducted in climate controlled rooms at Murdoch University where intensive monitoring was possible. In the Bos taurus, increases in core body temperature, reductions in feed intake, and increased water intake were measured. There were also changes in blood gas variables consistent with the observed panting causing a compensated respiratory alkalosis. Following the heating period, there were decreases in blood and urinary pH. Bos indicus showed similar responses to the heat, but the changes were less pronounced at the temperatures tested. A pair feeding experiment was conducted to separate the effects of heat from the reductions in feed intake, and this indicated that the major measured effects were due to the responses to heat. On the basis of the measured responses, an electrolyte supplement was formulated and tested on Bos taurus, in the climate controlled rooms, and then on a commercial live export vessel. Results from these experiments indicated improved buffering capacity and a weight advantage for supplemented cattle, even in the absence of extreme heat stress. A final experiment investigated the effects of amount and quality of roughage in a pelleted feed on core and rumen temperature and feed intakes in Bos taurus subjected to hot environmental conditions in climate controlled rooms at Murdoch University. Both pelleted feeds had approximately the same metabolisable energy and crude protein but differed in content and type of roughage. There were no differences in feed intake, core temperature or rumen temperature between diets. This work has led to a greater understanding of the physiological responses of cattle to prolonged and continuous high heat and humidity, the requirements and effects of supplemental electrolytes in these conditions, and the effect of manipulating export diets. The demonstration of advantages in weight and buffering capacity with the electrolyte supplement highlights future areas of research to investigate electrolyte doses, route and types of supplementation, and dietary manipulation.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1995. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Thesis--University of Copenhagen. / Also published in Acta Physiologica Scandinavica, Supplementum, 324. Summary in Danish. Bibliography: p. 105-110.

Thesis--University of Wisconsin. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 89-93).

As one of the most successful invasive species in the marine environment around the globe, the green crab Carcinus maenas possesses efficient regulatory mechanisms to quickly acclimate to environmental changes. The most important organs in this process are the nine pairs of gills that not only allow for osmoregulation, but have been shown to be involved in ammonia excretion and respiratory gas exchange. To date, however, little is known about the gills’ contribution to acid-base regulation that might become increasingly important in a “future ocean scenario” whereby surface ocean pH is predicted to drop by up to 0.5 units by the year 2100. The present thesis aims to characterize the green crab gills’ role in acid-base regulation and how it is linked to ammonia excretion. After exposure to hypercapnia (0.4 kPa pCO2 for 7 days), osmoregulating green crabs were capable of fully compensating for the resulting extracellular respiratory acidosis, while osmoconforming green crabs only partially buffered the accompanying drop in hemolymph pH after acclimation to 1% CO2 for 48 hours. Perfusion experiments on isolated green crab gills showed that different gills contributed to the excretion of H+ in an individual pattern and indicated that NH4+ is an important component of branchial acid excretion. Experiments on gill mRNA expression and pharmaceutical effects on isolated gills identified distinct epithelial transporters to play significant roles in branchial acid base regulation: Rhesus-like protein, basolateral bicarbonate transporter(s), cytoplasmic V-(H+)-ATPase, Na+/H+-exchanger, basolateral Na+/K+-ATPase, cytoplasmic and membrane bound carbonic anhydrase, and basolateral K+ channels. Regarding the latter, the present work provides the first sequence-based evidence for a potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel (CmHCN) capable of promoting NH4+ transport in the green crabs’ gill epithelium, and further demonstrates its direct involvement in branchial acid-base regulation. This highly conserved protein is a potentially important novel key-player in acid-base regulation in all animals. Interestingly, the observed principles linking acid-base to ammonia regulation in the decapod crustacean gill epithelium resemble many observations previously made in vertebrates. The data of the present thesis therefore provides valuable information for general acid-base regulation, while contributing substantially to our understanding of acid-base regulation in invertebrates. / February 2016

Orientador: Denise Vaz de Macedo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-24T05:55:20Z (GMT). No. of bitstreams: 1 Lourenco_ThiagoFernando_D.pdf: 1624409 bytes, checksum: 54e7eba5a4bdbf1b59b89b21e0879d81 (MD5) Previous issue date: 2013 / Resumo: O desempenho em corridas de 10 km (v10km) se correlaciona com velocidades pico de corrida durante um teste de VO2max (Vpico) e ao limiar ventilatório (vLV). No entanto, a relação entre a velocidade de corrida correspondente ao ponto de compensação respiratória (vPCR) e v10km ainda não está bem estabelecida. Fisiologicamente, a vPCR indica a capacidade de tamponamento sanguíneo, o que indica que exercício realizados acima da vPCR podem induzir acidose, trazendo alterações metabólicas prejudiciais ao desempenho. Porém, nenhum estudo investigou o comportamento do estado ácido-base sanguíneo em corredores submetidos à exercício em carga constante referente à vPCR. A forma com que os corredores distribuem suas velocidades ao longo da corrida também é importante para o desempenho. Em corridas de 10 km, grande parte dos estudos mostra que a estratégia adotada em eventos de longa duração se caracteriza por uma estratégia em forma de U. No entanto, nenhum trabalho comparou a estratégia de corrida com valores de vPCR. Um dos objetivos do presente estudo foi investigar o potencial da vPCR como preditor de desempenho e estratégia de corrida em 10 km e associar a estratégia de corrida adotada durante esse evento aos parâmetros ventilatórios encontrados no teste de esforço máximo (vLV, vPCR e Vpico). Paralelamente, buscamos observar a tolerância dos atletas e o comportamento de parâmetros relacionados ao estado ácido-base sanguíneo em quatro intensidades de exercício constante em esteira ergométrica. Participaram do estudo doze corredores recreacionais (R) e dezenove de elite (E) especializados em corridas de 10 km. Os corredores realizaram um teste de 10 km contra relógio em pista de 400 m para a determinação da v10km, um teste de esforço máximo para a determinação da vLV, vPCR e Vpico e um protocolo de carga constante. Todos participantes do grupo R realizaram aleatoriamente quatro corridas de, no máximo, 10 km nas intensidades vLV, vPCR, a 25% da diferença entre vPCR e Vpico (vV1) e Vpico. Os corredores do grupo E realizaram apenas uma corrida referente à vV1. No protocolo de carga constante, amostras de sangue capilar foram coletadas para análise do pH (bpH), lactato (bLac) e potássio (bK+) e HCO3- (bHCO3-) sanguíneos. Todos os protocolos foram realizadas com, pelo menos, 72 horas de recuperação. O ritmo de corrida dos atletas nos 10 km na pista correlaciona-se fortemente com vPCR (R2=0,92) e todos são capazes de completar 10 km na esteira ergométrica nessa velocidade. Todos os corredores recreacionais completaram 10 km nas intensidades vLV e vPCR, sem alterações no bpH. Na intensidade vV1, três corredores recreacionais e nove de elite foram capazes de completar 10 km sem alterações no bpH. Quedas significativa no bpH foram observadas nos corredores que não completaram 10 km em vV1 e Vpico. Em conclusão, nossos dados sugerem a manutenção do bpH como fator chave para a sustentação do exercício de 10 km em carga constante. Além disso, reforçam a vPCR como uma intensidade de exercício "segura¿ para o estratégias de corrida em 10 km / Abstract: The 10 km performance (s10km) correlates with running speeds related to VO2max (sVO2max) and ventilatory threshold (sVT). However, the relationship between running speed corresponding to the respiratory compensation point (sRCP) and v10km is not well established. Physiologically, sRCP indicates the buffering capacity of blood, which indicates that the exercise performed above sRCP can induce acidosis and decrease in motor output. However, no study has investigated the behavior of the blood acid-base status in runners undergoing constant load exercise related to sRCP. The way that runners distribute their running speeds throughout the race is also important for performance. In 10 km races, most studies show that the strategy adopted in is characterized by a U-shaped strategy. However, no study compared the running strategy to sRCP values. One objective of this study was to investigate the potential of sRCP as a predictor of 10 km performance, linking race strategy adopted during the 10 Km race to ventilatory parameters found in maximal exercise test (sVT, sRCP and sVO2max). In parallel, we would like to observe the tolerance of athletes and the behavior of blood acid-base status in four fixed exercise intensities. Twelve recreational runners (R) and nineteen elite runners (E) specialized in races of 10 km participated in this study. The runners performed a 10 km time trial on the track 400 m to determine the s10km, a maximal incremental exercise test to determine the sVT, sRCP and sVO2max and constant load protocol. All participants in the R group performed randomly four races at most 10 km in intensities related to sVT, sRCP, 25 % of the difference between sRCP and sVO2max (S1) and sVO2max. The E group underwent only a race related to S1. In the constant load protocol, capillary blood samples were collected for analysis of blood pH (bpH), lactate (bLac), potassium (bK+) and HCO3- (HCO3-). All protocols were performed at least with 72 hours recovery. The athletes race pace in 10 km on the track were strongly correlated with sRCP (R2=0.92) and all runners are able to complete 10 km on the treadmill at this intensity. All recreational runners completed 10 km in the intensities related to sVT and sRCP with no changes in bpH. At S1 intensity, three recreational and nine elite runners were able to complete 10 km with no changes in bpH. The bpH decreased significantly in in runners who have not completed 10 km in S1 and sVO2max. In conclusion, our data suggest the maintenance of bpH as a key factor for sustaining 10 km and indicate the sRCP as a ¿safe" exercise intensity for 10 km race strategies / Doutorado / Biodinamica do Movimento e Esporte / Doutor em Educação Física