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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Macroalgae in tropical seascapes : regulating factors and functions in the coastal ecosystem

Lilliesköld Sjöö, Gustaf January 2010 (has links)
Although macroalgae usually are inconspicuous on pristine coral reefs, they often thrive on reefs that are subjected to various types of anthropogenic disturbance. This thesis consists of five papers and investigates how biomass and composition of macroalgal communities on coral reefs are affected by regulating factors, such as nutrient availability, herbivory, substrate availability and hydrodynamic forces. In addition, ecological functions and potential impacts of both wild and farmed macroalgal communities are evaluated. Paper I describes a method for using macroalgal tissue nutrient concentrations as bioindicator for nutrient availability, with the possibility to map nutrient loading from larger coastal cities. Papers II and III are manipulative studies comparing top-down and bottom-up regulation of macroalgal communities, where herbivore consumption seems to be the main regulator of biomass whereas nutrient availability mainly influences community composition. Exclosure of large-bodied herbivores had a positive influence on algal biomass in both studies, and during different climatic periods. Paper III also includes the influence of hydrodynamic forces on algal community biomass and structure by comparing a reef crest and a back reef-habitat. Alterations of top-down and bottom-up regulation generally had a stronger effect within the protected back reef-habitat, suggesting that such environments may be more sensitive to anthropogenic influence. Paper IV confirms the general conclusions from papers II and III by studying macroalgal biomass and composition on reef sites with different environmental prerequisites. This study also supports the notion that herbivorous fish can suppress accumulation of macroalgal biomass if substrate availability is low, but not where coral cover is reduced and plenty of substrate is open to macroalgal colonization. The study also found a large temporal variation of macroalgal standing stock and associated nutrients at sites with low top-down regulation. Paper V evaluates potential impacts of seaweed farming on coral reefs and nutrients in the seascape by experimentally studying growth, survival and nutrient binding capacity of Eucheuma denticulatum. This study showed that seaweed farms counteract eutrophication through nutrient extraction and that the risk of farmed algae colonizing local reefs seems to be small as they were rapidly consumed. In conclusion, the studies in this thesis contribute to the understanding of macroalgal regulation and function in tropical seascapes, thereby adding to the knowledge base for coastal management. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript.</p>
22

Effects of running on hormonal growth factors

Blostein, Ashley C. January 1993 (has links)
To determine the influence of running on certain blood-born parameters that are involved in bone metabolism, serum levels of calcium, alkaline phosphatase (ALP, a marker of bone formation), growth hormone (hGH), and parathyroid hormone (PTH), were analyzed in 10 male subjects following a 40 min. run at 70% VO2max. Each trial was preceeded by 1 day of inactivity, a 8-12 hr. fast, and drawing of a baseline blood sample by venipuncture. All other blood samples were taken via an indwelling catheter which was inserted in an antecubital vein immediately following the completion of the exercise bout. When the catheter was in place, an "immediate post" sample was drawn. Subsequent samples were taken at 1, 2, 3, 4, 5, 10, 15, 20, 30, 45, and 60 min. after the immediate post sample. Analysis of serum calcium concentrations demonstrated that levels were significantly elevated by 12% following exercise, going from a fasted level of 9.7 ± .53 mg/dl to post-exercise levels of 11.8 ± .73 mg/dl. Serum calcium remained elevated during the first 4 min. following exercise. By 5 min. post-exercise, calcium levels dropped to levels that were significantly lower than the post-exercise sample. However, serum alkaline phosphatase did not change significantly following exercise, as the values remained within normal range throughout the experimental period. Concentrations tended to decrease over time but were not significantly lower than the preor post-exercise levels by the end of the sampling period. Serum concentrations of hGH were more than doubled following a single bout of exercise, going from 4.0 ± 0.98 ng/ml before exercise to 8.8 ± 1.6 ng/ml immediately post-exercise. Following this initial rise, hGH progressively declined and returned to baseline values by 30 min. post-exercise. The concentrations of PTH did not change significantly following exercise. The postexercise sample tended to be higher than baseline values but were not significantly different. The results presented here indicate that an exercise bout 40 min. at 70% V02max results in an elevation of serum calcium and hGH, but does not alter PTH secretion or ALP activity. The data presented in this study indicate that the temporary rise in calcium following exercise is unrelated to PTH. It is hypothesized that the increase in calcium that we observed is attributable to lactate accumulation that would result from an exercise bout of this nature. The buildup of lactic acid and drop in pH causes a dissolution of the crystaline calcium hydroxyapatite compartment of the skeleton, thus causing an increase in ionized calcium. It is not known whether a single bout of exercise can influence hormonal secretion to a sufficient degree to affect bone density, but the hormonal changes demonstrated here could be involved in long-term effects of training. / School of Physical Education
23

Effect of weight bearing exercise on hormonal growth factors

Sherwood, Jennifer J. January 1994 (has links)
Age-related bone loss is a serious public health problem affecting 15 to 20 million people in the United States (1). In the last decade, several studies have investigated the effects of repeated bouts of exercise on bone density. Although this increase in bone density is mediated via hormones and/or cellular metabolites few studies have linked the increase in bone density with changes in these hormones or metabolites. Therefore, the purpose of this study was to determine the effect of a single bout of weight bearing exercise on the growth factors that alter bone metabolism. Seven healthy female subjects (age 23 ± 5 yrs.) agreed to participate in this study. A V02 max test was administered to each subject to determine their overall fitness level. A treadmill speed corresponding to 70% of their V02 max was then developed and the subjects ran for 40 minm on the treadmill at that speed. Blood samples were drawn pre and 1, 2, 3, 4, 5, 10, 15, 20, 30, 45, and 60 min post-exercise and assayed for serum growth hormone, calcium, parathyroid hormone, and alkaline phosphatase. No significant change was found in parathyroid hormone, calcium, or alkaline phosphatase serum levels. Growth hormone was found to be significantly decreased 30, 45, and 60 min. post-exercise as compared to pre-exercise levels (7.089, 5.399, 4.728, and 11.28 ng/mL, respectively). While this indicates that exercise may cause a depression in growth hormone levels during recovery, the elevated pre-exercise levels of three of the seven subjects masked the exercise stimulated release of growth hormone. Growth hormone stimulates bone absorption via insulin-like growth factors and the GH data suggests that these hormones may have been released well after our last measurement time point. In conchusion, 40 minutes of running exercise at 70% of V02 max does not produce a change in any of the hormones or metabolic factors directly associated with calcium turnover in the bone, suggesting that acute exercise has no immediate effect on bone metabolism. However, the exercise protocol did stimulate GH release which influences bone growth indirectly by its ability to regulate IGF release. Therefore, even though no acute effects were evident, a single bout of exercise may alter the long term control of bone metabolism. / School of Physical Education
24

Regulation of Inverted Formin-1 (INF1) by Microtubule-Affinity Regulating Kinase 2 (MARK2)

Kulacz, Wojciech 30 April 2012 (has links)
The actin and microtubule cytoskeleton plays a critical role in the establishment of cell polarity. Cell processes like mitosis and migration rely on the reorganization of the cytoskeleton to properly function. One driver of cell polarity is the formin, Inverted Formin-1 (INF1). INF1 is able to induce F-actin formation, activate the Serum Response Factor (SRF) pathway, stabilize microtubules, associate with microtubules, and disperse the Golgi body. Regulation of INF1 is unique, since it does not possess conserved formin regulatory domains. However, INF1 does possess many potential phosphorylation sites. In this study, we demonstrate that INF1’s ability to induce F-actin stress fibers and activate SRF is inhibited by Microtubule-Affinity Regulating Kinase 2 (MARK2). Inhibition of INF1’s actin polymerization activity by MARK2 likely occurs near INF1’s C-terminus. However, MARK2 was unable to inhibit INF1’s ability to stabilize microtubules, associate with microtubules, and disperse the Golgi. Furthermore, we show that INF1 overexpression is associated with primary cilium absence and in some cases, the presence of long cilia, suggesting that INF1 plays a role in primary cilium formation.
25

Calmodulin binding to cellular FLICE like inhibitory protein modulates Fas-induced signaling and tumorigenesis in cholangiocarcinoma

Pawar, Pritish Subhash. January 2008 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed Sept. 19, 2008). Includes bibliographical references.
26

cFLIP regulates Fas-induced apoptosis and pro-inflammatory gene expression in human vascular smooth muscle cells /

Dishmon, Monja. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 71-91).
27

Ekosystemtjänsternas årstidsvariation och potentiella säsongsutveckling – en del av Swecos vit-, grön- och blåstrukturplan för Gällivare kommun

Ekelund, My January 2015 (has links)
The term Ecosystem Services describes all the direct and indirect contributions ecosystems have on human welfare. Fresh water, clean air, genetic diversity, recreation and inspiration are some examples of ecosystem services we get from nature but often take for granted. The human way of living affects our ecosystem and by transforming natural surfaces to unnatural surfaces important ecosystem and their services might be lost or hard to reconstruct. There is a growing support from the community that the value of ecosystem services should be integrated into decision-making in our society.   Gällivare municipality plans for a big infrastructure investment. By knowing which ecosystem services that are important for people living in the city of Gällivare, the municipality can take the ecosystem services into consideration and optimize and reach multifunctionality in natural surfaces providing important ecosystem services. As a part of Gällivare municipality’s work to integrate ecosystem services in their infrastructure investment, this thesis studies ecosystem services during different seasons in the city of Gällivare. This master thesis examines ecosystem services in four different places in Gällivare. An assessment of important ecosystem services in every place was done based on information during a workshop with Gällivare municipality. Eleven or twelve ecosystem services in every place were considered especially important for the municipality. The prioritized ecosystem services were the cultural and the regulating services. How people in the locality experience the cultural services, recreation, mental &amp; physical health; aesthetic appreciation, inspiration &amp; education; tourism and spiritual experience &amp; "sense of place" and what they think of the services' potential development in the future were further studied with a questionnaire and interviews. The regulating ecosystem service local climate regulation was further studied by calculations of the ability of vegetation and water to affect the local temperature. The ability of ecosystems to clean storm water and regulate water flows was studied by inspecting flood maps for the city of Gällivare and standard levels of pollutions in storm water from different land uses.  Early in the study it was found that, during the winter season, existing ecosystem services are mostly cultural services since the ecosystem is in rest during winter and thereby can't deliver the same diversity of services as in summer. During summer season, results showed that vegetation could affect local climate by stabilizing the temperature. The vegetation also delays water flows, which is important during spring when there is a large amount of melt water and during heavy raining. The amount of pollutions in surface water is also reduced by vegetation.
28

Inhibition of pH regulation as a therapeutic strategy in breast cancer

Meehan, James January 2017 (has links)
The abnormal regulation of H+ ions, leading to a reversed pH gradient in cancer cells when compared to normal cells, is considered to be one of the most distinctive features of cancer. However, this characteristic has yet to be fully exploited as a therapeutic target in cancer. This project assessed whether targeting pH regulating proteins, which permit cancer cells to survive in the hostile hypoxic and acidic tumour microenvironment, could produce an effective therapeutic response in breast cancer. The pH regulating proteins carbonic anhydrase IX (CAIX), Na+/H+ exchanger 1 (NHE1) and vacuolar (H+)-ATPase (V-ATPase) were the focus of this thesis. Initial experiments were conducted in 2D tissue culture before progressing into 3D, using models that more faithfully re-create the in vivo tumour microenvironment. Expression analysis conducted with MCF-7, MDA-MB-231 and HBL-100 human breast cancer cell lines cultured in 2D, and in 3D as multicellular tumour spheroids, showed that protein and mRNA levels of CAIX were very responsive to lower O2 concentrations. Both MDA-MB-231 and HBL-100 cells displayed large increases in CAIX expression levels in hypoxia, with the HBL-100 cell line exhibiting the largest change in CAIX mRNA (42-fold increase) and protein (78-fold increase) levels in 0.5% O2 conditions. Hypoxia inducible factor 1-α (HIF-1α) controls the expression of CAIX, but the induction of CAIX in hypoxic MCF-7 cells was lower in comparison to the other cell lines, despite the presence of similar levels of HIF-1α. The differences in CAIX expression observed between the cell lines was consistent with a varying activity of factor inhibiting HIF-1 (FIH-1), an oxygen sensor that controls signalling through HIF-1α, as siRNA targeting FIH-1 led to increased levels of CAIX in hypoxic MCF-7 cells. While NHE1 protein levels did increase in hypoxic conditions in MCF-7 cells in 3D, overall, the expression levels of both NHE1 and V-ATPase were not as responsive to changes in O2 concentrations when compared to CAIX across differing O2 conditions in each of the cell lines. Inhibitors targeting CAIX, NHE1 and V-ATPase were all shown to reduce cancer cell number in 2D culture conditions. Differing O2 conditions changed the sensitivity of these cell lines to CAIX inhibition. Cells cultured in 20% O2 conditions were responsive to CAIX inhibition, while acute hypoxic cells cultured in 0.5% O2 displayed an increased resistance to drug treatment. Chronically hypoxic cells, which had spent over 10 weeks in 0.5% O2 before treatment, exhibited a re-sensitisation to CAIX inhibition. 3D invasion assays demonstrated that CAIX inhibition significantly reduced the invasion of cells from MDA-MB-231 spheroids into collagen type 1 in both 20% O2 and 0.5% O2 conditions, while drugs targeting either NHE1 or V-ATPase had no such inhibitory effects. Preliminary clonogenic assays, used to assess radiation sensitivity and performed with MDA-MB-231 spheroids, indicated that inhibitors targeting CAIX and NHE1 led to a significant decrease in colony formation when combined with irradiation, compared to either drug treatment or irradiation alone. Further invasion assays, carried out with primary tissue derived from human patients, showed that drugs targeting CAIX retained their inhibitory effects when tested on heterogeneous cancer material of varying tumour subtypes. CAIX inhibition also exhibited anti-cancer effects in vivo on mouse MDA-MB-231 xenografts, significantly reducing the proliferation and growth of tumours within mice. Together, this work demonstrates that inhibitors targeting the pH regulation mechanisms of cancer cells have potential in the treatment of breast cancer, highlighted by their capacity to affect cancer cell number, cancer cell invasion, and their ability to combine with irradiation. Of the 3 pH regulatory molecules studied, CAIX appears to be the target with the most therapeutic potential.
29

Análises bioquímicas e hsitológicas na micropropagação de abacaxizeiro 'Gomo de Mel' submetido a reguladores vegetais

Fráguas, Chrystiane Borges [UNESP] 06 October 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-06Bitstream added on 2014-06-13T19:34:19Z : No. of bitstreams: 1 fraguas_cb_dr_botfca.pdf: 1400606 bytes, checksum: e3a3b343e1fdf633f6e3bb2a35833a4e (MD5) / Este trabalho teve como objetivo avaliar os efeitos da aplicacao exogena de poliaminas e TIBA (antiauxina) na micropropagacao e anatomia foliar de plantulas de abacaxizeiro eIAC Gomo-de-mel f e analisar os teores de poliaminas endogenas, atividade de peroxidase, proteina, IAA-oxidase e a provavel relacao com as diferentes fases da micropropagacao. Inicialmente, retiraram-se as gemas da coroa de frutos sadios e a assepsia foi realizada com hipoclorito de sodio comercial (2 a 2,5% de cloro ativo) a 30% por 20 minutos e lavadas por 3 vezes em agua destilada e autoclavada. Em seguida, inocularam-se as gemas em meio MS solido contendo diferentes combinacoes de BAP (0; 0,5; 1,0 e 1,5 mg L-1) e NAA (0; 0,5 e 1,0 mg L-1). Apos 60 dias, foram selecionados os melhores tratamentos para proliferacao das brotacoes, que foram individualizadas e transferidas para estes meios por mais trinta dias, em meio MS liquido. Plantas oriundas do experimento anterior tiveram as folhas cortadas e apenas segmentos de 1 cm foram inoculados em meio MS liquido contendo os diferentes tratamentos: T1-MS, T2-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA, T3-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM SPD, T4-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM SPM, T5-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM PUT, T6-MS + 10 mM SPD, T7-MS + 10 mM SPM e T8-MS + 10 mM PUT. Na ultima fase, segmentos foram inoculados em meio MS liquido contendo os tratamentos: T1-MS, T2-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA, T3-MS + 0,5 ÊM TIBA, T4-MS + 1,0 ÊM TIBA, T5-MS + 2,0 ÊM TIBA, T6-MS + 4,0 ÊM TIBA, T7-MS + 8,0 ÊM TIBA e T8-MS + 16,0 ÊM TIBA. Apos, as plantas foram aclimatizadas em substrato Plantmax e houve 100% de sobrevivencia, independente do tratamento. Foram realizados cortes histologicos foliares para estudar a influencia das poliaminas e TIBA na anatomia foliar... / The effects of exogenous polyamines and TIBA (antiauxin) application in the micropropagation, leaf anatomy of pineapple plants IAC Gomo-de-mel and the contents of endogenous polyamines, peroxidase activity, protein, IAA-oxidase and probable relationship with the different micropropagation phases were studied. Initially, the axillary bud explants were excised from the crown of healthy fruits and the asepsis was accomplished with sodium hypochloride (2 to 2,5% of active chlorine) 30% for 20 minutes and washed 3 times in distilled and autoclaveted water. After, the axillary buds were inoculated in MS solid medium containing the different BAP (0; 0,5; 1,0 and 1,5 mg L-1) and NAA (0; 0,5 and 1,0 mg L-1) combinations. After 60 days, the best treatments were selected for shoot proliferation that were individualized and transferred to these media for more 30 days, in MS liquid medium. Plants from the previous experiment had the leaves cut and just 1 cm segments were inoculated in MS liquid medium containing the different treatments: T1-MS, T2-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA, T3-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM SPD, T4- MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM SPM, T5-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA + 10 mM PUT, T6-MS + 10 mM SPD, T7-MS + 10 mM SPM and T8-MS + 10 mM PUT. In the last phase, segments were inoculated in MS liquid medium containing the treatments: T1-MS, T2-MS + 1,0 mg L-1 BAP + 0,5 mg L-1 NAA, T3-MS + 0,5 mM TIBA, T4-MS + 1,0 mM TIBA, T5-MS + 2,0 mM TIBA, T6-MS + 4,0 mM TIBA, T7-MS + 8,0 mM TIBA and T8-MS + 16,0 mM TIBA. After, the plants were acclimatizated in Plantmax substrate and there were 100% survival, independent of the treatment. Leaf cuts were made to study polyamines and TIBA influence in the leaf anatomy. The highest shoot number wasobserved with 1,0 mg L-1 BAP + 0,5 mg L-1 NAA, however with hyperhydricity...(Complete abstract click electronic access below)
30

Regulation of Inverted Formin-1 (INF1) by Microtubule-Affinity Regulating Kinase 2 (MARK2)

Kulacz, Wojciech January 2012 (has links)
The actin and microtubule cytoskeleton plays a critical role in the establishment of cell polarity. Cell processes like mitosis and migration rely on the reorganization of the cytoskeleton to properly function. One driver of cell polarity is the formin, Inverted Formin-1 (INF1). INF1 is able to induce F-actin formation, activate the Serum Response Factor (SRF) pathway, stabilize microtubules, associate with microtubules, and disperse the Golgi body. Regulation of INF1 is unique, since it does not possess conserved formin regulatory domains. However, INF1 does possess many potential phosphorylation sites. In this study, we demonstrate that INF1’s ability to induce F-actin stress fibers and activate SRF is inhibited by Microtubule-Affinity Regulating Kinase 2 (MARK2). Inhibition of INF1’s actin polymerization activity by MARK2 likely occurs near INF1’s C-terminus. However, MARK2 was unable to inhibit INF1’s ability to stabilize microtubules, associate with microtubules, and disperse the Golgi. Furthermore, we show that INF1 overexpression is associated with primary cilium absence and in some cases, the presence of long cilia, suggesting that INF1 plays a role in primary cilium formation.

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