1 |
An Experimental and Theoretical Analysis of Nitric Oxide in the MicrocirculationNamin, Shabnam M 27 June 2012 (has links)
Nitric Oxide (NO) is produced in the vascular endothelium where it then diffuses to the adjacent smooth muscle cells (SMC) activating agents known to regulate vascular tone. The close proximity of the site of NO production to the red blood cells (RBC) and its known fast consumption by hemoglobin, suggests that the blood will scavenge most of the NO produced. Therefore, it is unclear how NO is able to play its role in accomplishing vasodilation. Investigation of NO production and consumption rates will allow insight into this paradox.
DAF-FM is a sensitive NO fluorescence probe widely used for qualitative assessment of cellular NO production. With the aid of a mathematical model of NO/DAF-FM reaction kinetics, experimental studies were conducted to calibrate the fluorescence signal showing that the slope of fluorescent intensity is proportional to [NO]2 and exhibits a saturation dependence on [DAF-FM]. In addition, experimental data exhibited a Km dependence on [NO]. This finding was incorporated into the model elucidating NO2 as the possible activating agent of DAF-FM. A calibration procedure was formed and applied to agonist stimulated cells, providing an estimated NO release rate of 0.418 ± 0.18 pmol/cm2s.
To assess NO consumption by RBCs, measurements of the rate of NO consumption in a gas stream flowing on top of an RBC solution of specified Hematocrit (Hct) was performed. The consumption rate constant (kbl)in porcine RBCs at 25oC and 45% Hct was estimated to be 3500 + 700 s-1. kbl is highly dependent on Hct and can reach up to 9900 + 4000 s-1 for 60% Hct. The nonlinear dependence of kbl on Hct suggests a predominant role for extracellular diffusion in limiting NO uptake.
Further simulations showed a linear relationship between varying NO production rates and NO availability in the SMCs utilizing the estimated NO consumption rate. The corresponding SMC [NO] level for the average NO production rate estimated was approximately 15.1 nM. With the aid of experimental and theoretical methods we were able to examine the NO paradox and exhibit that endothelial derived NO is able to escape scavenging by RBCs to diffuse to the SMCs.
|
2 |
AOM Characterization and Removal Efficiency Using Various SWRO Pretreatment TechniquesNamazi, Mohammed 12 1900 (has links)
This study investigates the operation of dual media filter DMF during ambient and simulated algal bloom conditions, and the role of coagulation and dissolved air flotation (DAF) in mitigating the adverse effects of algal blooms on DMF performance. The study also highlights which AOM concentration as a function of biopolymer is critical to organic fouling in DMF pretreatment for Red Sea water desalination with RO. On the other hand, the present study has carried out another experiment on AOM fouling in comparison with bacterial organic matter (BOM) and humic organic matter (HOM) using two different pore sizes of UF ceramic membranes, 5 and 50 kDa. The main aim of this comparison is to examine fouling behavior and mechanism and removal efficiency. The study revealed that AOM can induce organic fouling in DMF during simulated algal bloom conditions at biopolymer concentrations as low as 0.2 mg C/L. DMF performance was strongly affected by AOM concentration as observed by flow rate decline through time. Liquid chromatography – organic carbon detection (LC-OCD) analysis showed higher removal rates of biopolymers than lower molecular weight fractions (i.e., humic substances, building blocks and low molecular weight neutrals) for all pretreatment scenarios. The study also indicated that while DMF performance was enhanced with coagulation and sedimentation, the most significant improvement in performance was observed for DMF operation preceded by coagulation and DAF. Hydraulic performance of DMF correlated well with biopolymers removal, with removal rates of 72%, 53% and 39%, for coagulation/DAF, coagulation/sedimentation, and no coagulation, respectively. For UF ceramic membranes, results showed that more TEP/organics were removed by the 5 kDa membranes compared to the 50 kDa membrane, which is accounted for lower MWCO. The UF 5 kDa membrane also showed low fouling formation than 50 kDa membrane for all of three types of organic matter tested. Analysis of the fouled membranes by SEM images showed that fouling was dominated by cake layer formation for the 5 kDa membrane while pore blockage followed by cake layer formation is apparent for the 50 kDa membrane.
|
3 |
Optimization of Dissolved Air Flotation for Algal Harvesting at the Logan, Utah Wastewater Treatment PlantElder, Andrew R. 01 December 2011 (has links)
This research evaluated dissolved air flotation (DAF) as a separation method for algae and phosphorus from municipal wastewater at the City of Logan, Utah Wastewater Reclamation Facility. DAF uses the supersaturation of air to raise suspended algae and other particles to the surface, where they can be easily removed. DAF, in conjunction with chemical coagulants and flocculants, can approach 95% algae and phosphorus removal. The algae removed using the DAF process will be used in the production of biofuels and bioplastics.
A pilot DAF unit was used to determine the optimum alum dose for total phosphorus (TP) and algae removal. In addition, a bench-scale jar test unit was used to study the effects of various alum and polymer doses on removal efficiencies at different times of the day. An optimal alum dose was found to be 30 mg/L based on results from both the pilot and bench-scale units. No advantage to adding polymer was found.
Algae removal efficiencies on the pilot DAF ranged from 68-70%, and the effluent algae concentration was reduced to 10 mg/L. Approximately 65% of the total phosphorus was removed, from 1.1 to 0.4 mg/L, which is low enough to meet regulations anticipated to be promulgated by the state of Utah. Using the assumption that the molar weight of algae is 3,550 g/mole, the molar ratio of Al/TSS was found to be 30.1 and the molar ratio of Al/TP was found to be 7.5.
Extracellular polymeric substances (EPS) excreted by algal cells act as a natural flocculant and may allow for chemical usage to be minimized. Autoflocculation and bioflocculation, natural processes caused by EPS production and an increased pH level, were not observed to be a significant factor.
The chemical dosing rates provide the City of Logan with basic operational parameters for a full-scale (15 million gallons per day) DAF plant, providing an effluent phosphorus level below 0.5 mg/L. The alum will cost $1,118 per day, with a daily electrical cost of approximately $149. This full-scale DAF plant would harvest 1,563 kg of algal biomass per day, with a cost per kilogram of algae at $0.81.
|
4 |
Caenorhabditis elegans: um modelo experimental para a análise dos efeitos agudos de extratos de erva-mate (Ilex paraguariensis) e uma ferramenta para a potencialização do Ensino de Ciências na Escola Básica / Caenorhabditis elegans: an experimental model for the analysis of the acute effects of extracts of yerba mate (Ilex paraguariensis) and a tool for empowerment of Science Teaching in Primary SchoolLima, Maria Eduarda de 08 August 2013 (has links)
Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-04-08T19:40:07Z
No. of bitstreams: 1
MARIA EDUARDA DE LIMA.pdf: 1668726 bytes, checksum: 655c909ebc2b571ed7a13299e5990961 (MD5) / Made available in DSpace on 2016-04-08T19:40:07Z (GMT). No. of bitstreams: 1
MARIA EDUARDA DE LIMA.pdf: 1668726 bytes, checksum: 655c909ebc2b571ed7a13299e5990961 (MD5)
Previous issue date: 2013-08-08 / A Ilex paraguariensis (Saint-Hilaire) popularmente denominada erva mate, trata-se de uma espécie arbórea que cresce naturalmente em florestas da América do Sul e é muito utilizada no preparo de uma bebida peculiar conhecida como chimarrão, mate ou teterê, dependendo de onde é consumida. Entre as substâncias conhecidas da erva mate estão os polifenóis, saponinas, xantinas, minerais e vitaminas e há um interesse em elucidar os efeitos desses componentes. Em decorrência disto, o presente estudo avaliou os efeitos da exposição aguda a extratos de diferentes ervas-mate (I. paraguariensis), provenientes da Argentina, Brasil e Uruguai em C. elegans. Objetivando a obtenção de extratos com composição similar aos ingeridos pela população, preparou-se a bebida da forma tradicional e empregou-se uma forma de extração que mimetiza seu consumo. A partir desses extratos (mates) foram realizados testes de sobrevivência, locomoção, reprodução, longevidade, resistência ao estresse e nível de espécies reativas utilizando a cepa Bristol N2 do C. elegans. Também verificamos a ativação do fator de transcrição DAF-16 e a regulação das enzimas SOD-3 e Catalase utilizando as cepas transgênicas que possuem a proteína verde fluorescente (GFP) fundida a estas vias, do III nematoide C. elegans. Foi possível verificar que os extratos não causaram letalidade e foram capazes de aumentar significativamente o tempo de vida deste organismo modelo. Apontamos a hipótese que esse resultado seja mediado pela ativação do fator de transcrição DAF-16, um gene homólogo ao FOXO (seres humanos), responsável por regular vários processos biológicos tais como longevidade, reprodução e resposta ao estresse. Esse fator, quando ativado transloca do citosol para o núcleo, e ativa a expressão de genes alvo que codificam enzimas antioxidantes, como a SOD-3. Embora os extratos que aumentaram significativamente a longevidade tenham também aumentado a translocação de DAF-16 para o núcleo, curiosamente não aumentaram a expressão das enzimas SOD-3 e Catalase, indicando que podem haver outras vias envolvidas neste efeito. O Caenorhabitis elegans é um nematoide de vida livre do solo que tem sido muito utilizado no âmbito da pesquisa científica atual e além de ser um ótimo e bem descrito modelo, pode ser utilizado para potencializar o Ensino de Ciências na Escola Básica através de uma proposta inovadora. Portanto, além da pesquisa científica, o presente trabalho apresentou uma proposta de trabalho diferenciada para o Ensino de Ciências e saúde nos anos iniciais da Escola Básica, utilizando o C. elegans como modelo alternativo. Este estudo sintetiza uma contribuição importante para futuras pesquisas, tanto porque pela primeira vez mostra os efeitos de extratos de diferentes nacionalidades obtidos na forma como a população habitualmente consome em C. elegans, sendo o ponto de partida para investigações de mecanismos envolvidos nos efeitos supracitados, quanto porque mostrou que métodos alternativos de experimentação científica podem potencializar o aprendizado de Ciências e melhorar a capacidade de entendimento dos alunos, através do despertar da curiosidade e estimulo de uma maior participação efetiva nas aulas, indicando que métodos inovadores devem ser mais explorados. / Ilex paraguariensis (St. Hilaire) popularly called yerba mate, it is a tree species that grows naturally in the forests of South America and is widely used in the preparation of a peculiar drink known as mate, or tererê, depending on where is consumed. Among the known substances of the mate are polyphenols, saponins, xanthines, vitamins and minerals and there is an interest in elucidating the effects of these components. Due to this, the present study evaluated the effects of acute exposure to extracts of different herbs mate (I. paraguariensis), from Argentina, Brazil and Uruguay in C. elegans. In order to obtain extracts with similar composition to ingested by the population, prepared to drink the traditional way and we used a form of extraction that mimics its consumption. From these extracts (mates) tests were performed for survival, locomotion, reproduction, longevity, stress resistance and level of reactive species using the Bristol N2 strain of C. elegans. We also found activation of the transcription factor DAF-16 and the regulation of the enzymes SOD and Catalase-3 using strains that have transgenic green fluorescent protein (GFP) fused to these pathways, the nematode C. elegans. It was possible that the extracts did not cause lethality and were able to significantly increase the II lifespan of this model organism. We point out the possibility that this result is mediated by activation of the transcription factor DAF-16, a gene homologous to the FOXO (humans), responsible for regulating various biological processes such as longevity, reproduction and stress response. This factor, when activated translocates from the cytosol to the nucleus and activates the expression of target genes encode enzymes that antioxidants, such as SOD-3. Although the extracts which have significantly increased the longevity also increased translocation of-16 to DAF core, interestingly not increased expression of SOD and Catalase-3, indicating that other pathways may be involved in this effect. The Caenorhabitis elegans is a free-living nematode soil that has long been used in the context of current scientific research and besides being a great and well-described model can be used to enhance the Teaching of Science in Primary School through an innovative. So in addition to scientific research, this paper proposed a differentiated work for Teaching Science and Health in the early years of the Basic School, using C. elegans as alternative model. This study summarizes an important contribution to future research, both because the first time shows the effects of extracts obtained from different nationalities in the way people usually consume in C. elegans, and the starting point for the investigation of mechanisms involved in the effects described above, as it has shown that alternative methods of scientific experimentation can enhance learning science and to improve understanding of the students, through the awakening of curiosity and stimulate greater effective participation in classes, indicating that innovative methods should be further explored.
|
5 |
Linguistic Fieldnotes II: Information structure in different variants of written GermanFreywald, Ulrike, Mayr, Katharina, Schalowski, Sören, Wiese, Heike January 2010 (has links)
Dieser Band versammelt Originaldaten aus einer Erhebung, die im Rahmen des SFB-Teilprojekts B6 „Kiezdeutsch“ im Frühjahr 2010 in Berlin und İzmir, Türkei, durchgeführt wurde. Sämtliche hier dokumentierten Daten wurden schriftlich produziert; sie stammen von drei verschiedenen Sprechergruppen: Jugendliche aus einem multiethnischen Berliner Wohngebiet, die untereinander Kiezdeutsch sprechen, Jugendliche aus einem monoethnischen Berliner Wohngebiet, in dem der traditionelle Berliner Dialekt vorherrscht, und türkische Jugendliche in İzmir, die Deutsch als Fremdsprache gesteuert erworben haben.
|
6 |
Avaliação molecular da variabilidade genética do banco ativo de germoplasma de melancia do Nordeste brasileiroLuciene da Silva, Maria 31 January 2010 (has links)
Made available in DSpace on 2014-06-12T18:02:35Z (GMT). No. of bitstreams: 2
arquivo893_1.pdf: 4194750 bytes, checksum: db25c32a6384a62bbed9cd11a9087dcb (MD5)
license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)
Previous issue date: 2010 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Com o objetivo de estudar a variabilidade genética entre os acessos de melancia do Banco
Ativo de Germoplasma de Cucurbitáceas para o Nordeste Brasileiro (Petrolina PE, Brasil),
um levantamento no acervo resultou na localização de 753 acessos (agricultura tradicional,
espécies do centro de origem e variedades comerciais) e 300 linhagens (produtos do
melhoramento) com dados de passaporte. Destes, 291 foram avaliados quanto à variabilidade
genética, com 16 primers DAF e 11 primers ISSR, incluindo dois acessos de melão (Cucumis
melo) como grupo externo. Os dados foram analisados no programa NTSYS para a estimativa
do coeficiente de similaridade de Jaccard e na obtenção dos dendrogramas pelo método
UPGMA. As análises dos dados dos marcadores DAF e ISSR revelaram altos índices de
polimorfismo (65,3% e 76,9%, respectivamente). Os marcadores DAF foram pouco
informativos na separação dos acessos em grupos, não correspondendo com a taxonomia do
gênero Cucumis e Citrullus, porém indicam que há variabilidade expressiva entre os acessos
coletados na agricultura tradicional do Nordeste brasileiro, inclusive, mostrando divergência
entre os grupos de linhagens analisadas. Os marcadores ISSR revelaram boa precisão na
separação das diferentes espécies, sendo determinantes na identificação de polimorfismo e
agrupamento dos acessos e linhagens de melancia. Constatou-se grande porcentagem de
variação dentro dos quatro conjuntos de germoplasma do banco (76,7%), inclusive
identificando que os produtos do melhoramento apresentaram 87,4% de variação dentro dos
três grupos de linhagens. Esses resultados indicam que o banco agrega germoplasma muito
promissor para dar suporte a programas de melhoramento de melancia no Nordeste Brasileiro.
Espacialmente, a maior porcentagem de variação foi encontrada nos acessos coletados dentro
de cada Estado (86,1%) e de municípios (76,2%) ou grupos de municípios próximos (73,1%)
indicando que há necessidade imperiosa de continuar o resgate de germoplasma de melancia
da agricultura tradicional nos Estados e municípios ou grupos de municípios não
contemplados nesta pesquisa
|
7 |
Variabilidade genética em populações de Ricinus communis (Euphorbiaceae) pela metodologia de DAF (DNA Amplification FingerprintingSantana de Oliveira, Nilmara January 2004 (has links)
Made available in DSpace on 2014-06-12T18:06:46Z (GMT). No. of bitstreams: 2
arquivo6319_1.pdf: 813959 bytes, checksum: ac0fdfeef1e3a6adeb19be879b540aad (MD5)
license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)
Previous issue date: 2004 / O Brasil ocupa mundialmente a terceira posição na produção de mamona (Ricinus communis L.). Embora existam muitos estudos moleculares voltados às proteínas expressas nas sementes, não existem até o momento análises com marcadores moleculares avaliando a diversidade genética dessa espécie. O presente trabalho estudou a variabilidade genética de 16 genótipos de populações subespontâneas de mamona adquiridas através de coletas em quatro diferentes localidades de Pernambuco e em duas outras regiões do Brasil, comparando-as a acessos cultivados de quatro outros países. Para isso a metodologia de DAF (DNA amplification Fingerprinting) foi utilizada, permitindo a geração de em média 14 bandas por primer, sendo 10,72 polimórficas, a partir de 11 primers. Para a construção da matriz de dados 143 bandas foram analisadas, perfazendo 2.288 caracteres. A análise filogenética de máxima parsimônia revelou uma diversidade genética significativa, entre genótipos da mesma população, considerando os diferentes pontos de coleta no Brasil, bem como comparativamente com acessos cultivados no exterior. O estudo confirma a variabilidade sugerida pelos melhoristas para as populações subespontâneas de mamona e demonstra a eficiência deste tipo de marcador para estudos de caracterização de germoplasma desta importante cultura vegetal.
|
8 |
Modulation of small RNA silencing by cross-generational signaling in C. elegansChoi, Youngeun 04 June 2016 (has links)
Organisms are constantly challenged by the surrounding environment and alter their physiology accordingly. Some environment-induced changes in one generation are inherited in the offspring, and this long-lasting memory of parental experience has gained a lot of attention recently due to its implications in the organism's development and health. One example is transmission of RNAi-induced silencing from parents to progeny in C. elegans. Although this phenomenon has been known for more than a decade, the parental contribution to RNAi inheritance is still unclear. Here, we show that the nuclear hormone receptor DAF-12 mediates a cross-generational signaling that regulates RNAi in zygotes. Pol II ChIP-qPCR revealed that normally, DAF-12 enhances transcriptional repression induced by RNAi. Mutant analysis demonstrated that the role of DAF-12 in RNAi is distinct from its function in developmental timing or heterochronic pathways. Surprisingly, DAF-12 acts in mothers to alter the RNAi efficiency in zygotes, indicating the presence of mother-to-offspring, DAF-12-dependent signals that enhance RNAi in zygotes. Considering the previous studies showing that the function of DAF-12 is determined by environmental cues, we tested and found that the role of DAF-12 in RNAi enhancement in zygotes depends on the environmental cues presented to mothers during their development. These results demonstrate a novel role of DAF-12 as a modulator of RNAi and its contribution to cross-generational signaling. Moreover, the findings imply a potential interaction between environmental conditions and small RNA pathways.
|
9 |
A versatile approach for combined algae removal and biofouling control in seawater reverse osmosis (SWRO) desalination systemsAlshahri, Abdullah 02 1900 (has links)
The goal of this study was to evaluate the feasibility of using advanced coagulation with
Fe(VI) in coagulation-flocculation-sedimentation/ flotation systems for the pretreatment
of SWRO desalination plants during algal bloom events.
Algal organic matter (AOM) material extracted from marine diatom species (Chaetoceros
affinis) was added to Red Sea water to mimic algal bloom conditions. Low dosage of
Fe(VI) (<1 mg Fe/L) was very effective at improving feed water quality containing AOM
(algal bloom conditions). Based on results from both a bench-scale DAF unit and Jar
testing unit, 0.75 mg Fe/L of Fe (VI) proved to be effective at improving the raw water
quality which is comparable to the performance of 1 and 3 mg Fe/L of Fe (III). The
removal efficiency for both testing units with the use of Fe(VI) was up to 100% for algae
, 99.99% for ATP, 99% for biopolymers and 70 % for DOC. The improvement in Fe(VI)
performance is related to the simultaneous action of Fe(VI) as oxidant, disinfectant and
coagulant.
The performance of Fe(VI) coagulant was also evaluated with the use of coagulant aids
(clays). The overall turbidity, DOC, biopolymers and algal cells removal was improved
via using Fe(VI) and clays at very low dose. Generally, it was found that for the same
pretreatment performance achieved, a much lower Fe(VI) dose was required compared to
Fe (III), which make it important to study of cost effectiveness for using Fe(VI) instead
of Fe(III) and estimate cost savings during algal bloom conditions.
A detailed cost comparative study was conducted for Fe(III) vs. Fe(VI) coagulation
process based on the removal efficiency. The use of Fe(VI) reduced the total pretreatment
cost by 77% and sludge disposal cost by > 88% compared to the use of Fe(III) in the
pretreatment process. The use of Fe(VI) reduces the operational and maintenance cost in
SWRO desalination plant by 7% and the production cost by 4%. This study proved that
the use of Fe(VI) during high turgidity and algal bloom conditions helped providing high
raw water quality to the RO process with lower chemicals and operations cost as well as
low chlorine and iron residuals.
|
10 |
Regulation of T cell Immune Responses by Decay Accelerating FactorLalli, Peter Nicholas January 2008 (has links)
No description available.
|
Page generated in 0.0771 seconds