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Influência de aditivos redutores e compensadores de retração em argamassas e pastas com cimento de escória ativada. / Effect of shrinkage compensating and reducing admixtures in alkali activated slag mortars and pastes.Antônio Acacio de Melo Neto 11 December 2007 (has links)
O objetivo desta tese foi o estudo da influência do aditivo redutor de retração (SRA) e o aditivo compensador de retração (SCA) em argamassas e pastas de cimento de escória ativada com silicato de sódio. A metodologia foi centrada na análise da retração por secagem e autógena, com o estudo de outras características que influenciam no fenômeno da retração, como as propriedades mecânicas. Para o avanço no conhecimento do efeito dos aditivos no comportamento do cimento de escória, foi caracterizada a microestrutura com a determinação da análise por termogravimetria, porosimetria e difração de raios X. Neste estudo foram empregados os seguintes teores de aditivo, porcentagem relativa à massa de aglomerante: 0,5%, 1%, 1,5% e 2% do aditivo SRA e 5%, 10% e 15% do aditivo SCA. Para a análise da influência da relação a/agl foram empregadas três teores: 0,40, 0,48 e 0,56. No estudo das amostras de referência, sem a utilização de aditivo, observou-se que o aumento da relação a/agl causa o aumento da retração por secagem e da retração autógena do cimento de escória ativada. A diminuição da resistência mecânica com o aumento da relação a/agl, o que torna o esqueleto sólido mais susceptível à deformações, e o aumento das tensões capilares, em razão do aumento da quantidade de água livre para ser evaporada, são os principais fatores para o aumento da retração por secagem. No caso da retração autógena, seu aumento é atribuído ao aumento da auto-secagem com o aumento do volume de poros com diâmetro na faixa de mesoporos, além da diminuição da resistência mecânica. O aditivo redutor de retração (SRA) conseguiu reduzir a retração por secagem em percentuais de 40% até 74% aos 28 dias, no entanto, este tipo de aditivo não obteve êxito no combate a retração autógena. Com relação à resistência mecânica, o aditivo SRA causou a redução de até 40%, efeito atribuído à diminuição do grau de hidratação e retardo do refinamento da porosidade. O aditivo compensador de retração (SCA) amenizou a retração por secagem e a retração autógena, reduzindo em até 64% e 70%, respectivamente, porém reduziu em até 60% a resistência mecânica do cimento de escória ativada. Com relação à microestrutura, o aditivo SCA diminuiu o grau de hidratação e aumentou a porosidade total, com o aumento da proporção do volume de macroporos. / The aim of this research was the study of the influence of shrinkage reducing admixture (SRA) and shrinkage compensating admixture (SCA) in mortars and pastes of blast furnace slag activated with sodium silicate. The method was centered in the analysis of free drying and autogenous shrinkage, with other characteristics that affect the shrinkage, as the mechanical properties. The microstructure behavior was accomplished with thermogravimetry (TG), mercury intrusion porosimetry (MIP) and X-ray diffraction (XRD). The samples were prepared with 0,5%, 1%, 1,5% and 2% of SRA admixture and 5%, 10% and 15% of SCA admixture, by binder mass. The effect of water/binder ratio was accomplished in three contents: 0,40, 0,48 and 0,56. In the reference mixtures, without admixtures, it was observed that an increase of water/binder ratio incurs in an increase of drying and autogenous shrinkage of alkali activated slag. The explanations for drying shrinkage behavior are the decrease of mechanical strength as consequence of water/binder increase, that turns the porous structure more susceptible to deformations, and the increase of the capillary tensions, attributed to the increase of free water to be evaporated. The increase of autogenous shrinkage with water/binder ratio is attributed to the increase of pore volume with diameter in the mesopores range, besides the decrease of the mechanical strength. The shrinkage reducing admixture (SRA) diminish drying shrinkage of 40% up to 74% at 28 days, however, this type of admixture was not capable to combat the autogenous shrinkage. About mechanical strength, the SRA admixture incurs in a decrease up to 40% of compression strength that it was attributed to the decrease of the hydration degree and retard of pore size refinement. The shrinkage compensating admixture (SCA) softened drying and autogenous shrinkage, reducing in up to 64% and 70%, respectively. However, the SCA admixture decreases in up to 60% mechanical strength of alkali activated slag. About microstructure, SCA admixture reduced the hydration degree and it increased the total porosity, with the increase of macropores volume.
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Estudo dialélico para caracteres agronômicos em pinhão-manso (Jatropha curcas L.) / Diallel study for agronomic traits in physic nut (Jatropha curcas L.)Santana, Ulisses Andrade 25 February 2013 (has links)
The physic nut (Jatropha curcas L.) is oilseed species belonging to Euphorbiaceae family with a widespread distribution in tropical regions. The quality and high oil content in seeds, perenicity and rusticity makes this species a potential feedstock for biodiesel production. However, the success of this insertion involves research ranging from the exploration of divergent genetic materials to selection and acquisition of productive cultivars. In this context, this study aimed to assess the combining ability of jatropha access for agronomic traits of interest, as well as information about genetic parameters associated with morphological and agronomic characters, and investigate their correlations. The study was carried out in the Experimental Farm of the UFS during the year 2012 in hybrids of jatropha evaluated up to 24 months. The experimental design was in randomized blocks with three replications and plots with six plants. There were evaluated seed yield (PR), plant height (PH), number of secondary branches (NRS), the number of female flowers (NFF), stem diameter (DC), 100-seed weight (P100 ), branching height (AR) and crown diameter (DCO). The general combining ability (GCA) was significant for the variables PR, DC, NRS and AR (Group 1) and P100 and NRS (Group 2), whereas specific combining ability (SCA) was significant for variables NFF and NRS. The sum of squares due to GCA was higher than the sum of squares due to SCA for the majority of traits, indicating that the additive effects of loci are more important than the dominance effect loci. The genitors JCUFS-04 and JCUFS-05 highlight from the others for concentration of favorable alleles. The consistent estimation of the coefficient of genetic variation allows us to infer the existence of significant genetic variability among hybrids. The characters which more contributed to genetic diversity were NFF (20.99%), DC (16.83%), PR (15.06%), and NRS (14.06). High, significance and positive genotypic correlations were recorded among (NRS), (DC), (DCO) and grain yield (PR). / O pinhão-manso (Jatropha curcas L.) é uma espécie oleaginosa da família Euphorbiaceae com ampla distribuição em regiões tropicais. A qualidade de óleo e alto teor nas sementes, perenicidade e rusticidade fazem desta espécie uma matéria-prima potencial para produção de biodiesel. Todavia, o sucesso desta inserção passa por pesquisas que vão desde a prospecção de materiais genéticos divergentes, até a seleção e obtenção de cultivares produtivos. Nesse contexto, esse trabalho teve por objetivo avaliar a capacidade combinatória de acessos de pinhão-manso, para caracteres de interesse agronômico, bem como, obter informações acerca de parâmetros genéticos associados a caracteres morfo-agronômicos, e investigar a correlação entre estes. O trabalho foi realizado na Fazenda experimental da UFS durante o ano de 2012 em híbridos de pinhão-manso avaliados até os 24 meses de idade. O delineamento experimental empregado foi em blocos casualizados com três repetições e parcelas compostas por seis plantas. Os caracteres avaliados foram rendimento de sementes (PR), altura de planta (AP), número de ramos secundários (NRS), número de flores femininas do racemo floral (NFF), diâmetro de caule (DC), massa de 100 sementes (P100), altura de ramificação (AR) e diâmetro de copa (DCO). A capacidade geral de combinação (CGC) foi significativa para as variáveis PR, DC, NRS e AR (Grupo 1) e para P100 e NRS (Grupo 2), enquanto a capacidade específica de combinação (CEC) foi significativa para as variáveis NFF e NRS. A soma de quadrados devido à CGC foi maior que a soma de quadrados devido à CEC para a maioria dos caracteres, indicando que os locos de efeito aditivo têm maior importância que os locos de efeito dominante. Os genitores JCUFS-04 e JCUFS-05 se destacaram dos demais quanto à concentração de alelos favoráveis. As estimativas consistentes dos coeficientes de variação genética permitem inferir sobre a existência de variabilidade genética significativa entre os híbridos obtidos. Os caracteres que mais contribuíram para a diversidade genética encontrada entre a populações foram, NFF (20,99%), DC (16,83%), PR (15,06%) e NRS (14,06). Altas e significativas correlações genotípicas positivas foram registradas entre (NRS), (DC), (DCO) e o rendimento de grãos (PR).
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Effektiv webbdesign i e-handeln : Design som ökar slutförandet av köp i webbutiker / Effective web design in e-commerce : Using design to motivate customers to complete their purchasesBodell, Nicklas January 2020 (has links)
Samhället blir allt mer digitaliserat för var dag som går och med denna utveckling har e-handeln under de senaste decennierna kontinuerligt vuxit sig större. I den växande e-handeln existerar det dock ett problem som leder till stora monetära förluster för aktörer i detaljhandeln. Enligt aktuell statistik överger över två tredjedelar av alla kunder i e-handeln sina fyllda varukorgar utan att avsluta sina köp. Anledningarna bakom detta pekar i vissa fall på känslor som uppstår hos användare på grund av hur webbutiker är uppbyggda och fungerar. Denna studie har med bakomliggande problemområde som anledning därför undersökt hur design skulle kunna tillämpas för att öka slutförandet av köp i webbutiker. För att besvara denna fråga har en kvalitativ undersökning gjorts där intervjuer konstruerade efter tidigare forskning inom området och forskningsfrågan utfördes med personer som frekvent använder webbutiker och som även vid något tillfälle har lagt produkter i sin varukorg för att sedan lämna webbutiken utan att slutföra sitt köp. Resultaten från dessa intervjuer och den efterföljande analysen hittade de två användningsområdena ”Navigationssystem” och ”Kassa och varukorg” och tillhörande designriktlinjer som ska tillämpas i användningsområdena för att öka slutförandet av köp i webbutiker. Slutligen gestaltades även designförslag för att visualisera dessa användningsområden och designriktlinjer. / Society is becoming increasingly more digitized and with this development e-commerce has seen continuous growth these past decades. Within the growing e-commerce there is a however a big problem that has led to and continues to lead to significant monetary losses. According to current statistics over two thirds of customers online abandon their shopping carts without completing their purchases. In some cases, the reasons for this points to different emotions felt by customers which are created by how webshops are built and how they work. Due to this problem this study has researched how one could apply design to increase the completion of purchases in online stores. To answer this question a qualitative study was carried out in which interviews based on the research question and previous relevent research were conducted with people who frequently use online stores and who at some point have abandoned their shopping cart without completing their purchase. The result of these interviews and the subsequent analysis was the finding of the two areas ”Navigation system” and ”Checkout and shopping cart” in which design can be used to increase the completion of purchases and design guidelines that are to be applied when designing these areas with the purpose of reducing shopping cart abandonment. Lastly, design mockups where created to visualize these areas with the design guidelines applied.
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The Relationships Among Health Literacy, Stigma, Self-efficacy, Self-care, and Health Outcomes in Patients with Sickle Cell DiseaseO'Brien, Julia Ann 21 June 2021 (has links)
No description available.
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Design Methods for CryptanalysisJudge, Lyndon Virginia 24 January 2013 (has links)
Security of cryptographic algorithms relies on the computational difficulty of deriving the secret key using public information. Cryptanalysis, including logical and implementation attacks, plays an important role in allowing the security community to estimate their cost, based on the computational resources of an attacker. Practical implementations of cryptanalytic systems require complex designs that integrate multiple functional components with many parameters.
In this thesis, methodologies are proposed to improve the design process of cryptanalytic systems and reduce the cost of design space exploration required for optimization.
First, Bluespec, a rule-based HDL, is used to increase the abstraction level of hardware design and support efficient design space exploration. Bluespec is applied to implement a hardware-accelerated logical attack on ECC with optimized modular arithmetic components. The language features of Bluespec support exploration and this is demonstrated by applying Bluespec to investigate the speed area tradeoff resulting from various design parameters and demonstrating performance that is competitive with prior work. This work also proposes a testing environment for use in verifying the implementation attack resistance of secure systems. A modular design approach is used to provide separation between the device being tested and the test script, as well as portability, and openness. This yields an open-source solution that supports implementation attack testing independent of the system platform, implementation details, and type of attack under evaluation. The suitability of the proposed test environment for implementation attack vulnerability analysis is demonstrated by applying the environment to perform an implementation attack on AES.
The design of complex cryptanalytic hardware can greatly benefit from better design methodologies and the results presented in this thesis advocate the importance of this aspect. / Master of Science
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Utilisation du séquençage à haut débit dans l’identification des gènes prédisposant à l’épilepsie et aux syndromes neurocutanésCadieux-Dion, Maxime 04 1900 (has links)
No description available.
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Kampen om Piteå handelshamn 1950 - 1973 : från lokal stadshamn till nationell handelshamnJohansson, Rolf January 2011 (has links)
Survey's purpose is to illustrate why and how the process happened when Piteå relocated its commercial port away from Skuthamn to the new construction on Haraholmen 1950-1973. How decision-makers worked to achieve their goals, how the work changed and what incentives motivated them to act. The results showed that the decision was taken not to retain the existing commercial port in large part due to Skuthamns physics attributes, which made it impossible to ship large deep vessels from there. The reason that the decision about the port took such a long time was due to a local political conflict which was based on interest in the ownership of Haraholmen. The reason for the location of the trading port became Haraholmen had political backgrounds. The study's methodology is qualitative and describes the events chronologically. / Undersökningens syfte är att belysa varför och hur processen gick till när Piteå flyttade sin kommersiella hamn bort från Skuthamn och byggde upp den nya internationella handelshamnen på Haraholmen 1950-1973. Hur beslutsfattarna arbetade för att nå sina mål, hur förändrades deras arbetsmetoder med tiden och vilka incitament som motiverade dem att agera. Resultaten visade att beslutet som fattades att inte behålla den befintliga kommersiella hamnen Skuthamn som Piteås handelshamn till stor del berodde på att Skuthamns fysiska attribut omöjliggjorde transporter dit med stora djupgående fartyg. Anledningen till att beslutet om hamnen tog så lång tid berodde på en lokalpolitisk konflikt som grundade sig i vilken aktör som innehade äganderätten av markområdet på Haraholmen. Anledningen till lokaliseringen av handelshamnen på Haraholmen hade sin bakgrund i statens transportpolitik. Metoden som använts är kvalitativ och beskriver händelserna kronologiskt.
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Traffic aware resource allocation for multi-antenna OFDM systemsVenkatraman, G. (Ganesh) 14 September 2018 (has links)
Abstract
This thesis focuses on two important challenges in wireless downlink transmission: multi-user (MU) precoder design and scheduling of users over time, frequency, and spatial resources at any given instant. Data streams intended for different users are transmitted by a multiple-input multiple-output (MIMO) multi-antenna orthogonal frequency division multiplexing (OFDM) system. The transmit precoders are designed jointly across space-frequency resources to minimize the number of backlogged packets waiting at the coordinating base stations (BSs), thereby implicitly performing user scheduling.
Then the problem of multicast beamformer design is considered wherein a subset of users belonging to a multicasting group are served by a common group-specific data. The design objective is to either minimize the transmit power for a guaranteed quality-of-service, or to maximize the minimum achievable rate among users for a given transmit power. Unlike existing techniques, the proposed design utilizes both the spatial and frequency resources jointly while designing multi-group beamformers.
As an extension to coordinated precoding, the problem of beamformer design for cloud radio access network is considered wherein beamformers are designed centrally, quantized and sent along with data to the respective BSs via backhaul. Since the users can be served by multiple BSs, beamformer design becomes a nonconvex combinatorial problem. Unlike existing solutions, beamformer overhead is also included in the backhaul utilization along with the associated data. As the number of antennas increases, backhaul utilization is dominated by the beamformers. Thus, to reduce the overhead, two techniques are proposed: varying the quantization precision, and reducing the number of active antennas used for transmission.
Finally, to reduce the complexity involved in the design of joint space- frequency approach, a two-step procedure is proposed, where a MU-MIMO scheduling algorithm is employed to find a subset of users for each scheduling block. The precoders are then designed only for the chosen users, thus reducing the complexity without compromising much on the throughput. In contrast to the null-space-based existing techniques, a low-complexity scheduling algorithm is proposed based on vector projections. The real-time performance of all the schedulers are evaluated by implementing them on both Xilinx ZYNQ-ZC702 system-on-chip (SoC) and TI TCI6636K2H multi-core SoC. / Tiivistelmä
Tässä väitöskirjassa keskitytään kahteen tärkeään langattoman tiedonsiirron haasteeseen alalinkkilähetyksissä: usean käyttäjän (MU) esikooderisuunnitteluun ja käyttäjien skedulointiin aika-, taajuus- ja tilaresurssien yli. Eri käyttäjille tarkoitettuja datavirtoja lähetetään käyttämällä monitulo-monilähtötekniikkaa (MIMO) yhdistettynä monikantoaaltomodulointiin (OFDM). Lähettimien esikooderit suunnitellaan yhteisesti tila- ja taajuusresurssien yli, jotta keskenään yhteistoiminnallisten tukiasemien jonossa olevien pakettien määrää voitaisiin minimoida samalla kun tehdään epäsuorasti käyttäjien skedulointia.
Tämän jälkeen työssä paneudutaan monilähetysten (multicast) keilanmuodostussuunnitteluun, jossa monilähetysryhmään kuuluvien käyttäjien alijoukolle lähetetään yhteistä ryhmäspesifistä dataa. Suunnittelun päämääränä on joko minimoida kokonaislähetysteho tietyllä palvelunlaatuvaatimuksella tai maksimoida pienin saavutettavissa oleva siirtonopeus käyttäjien joukossa tietyllä lähetysteholla. Toisin kuin olemassa olevat menetelmät, ehdotetussa mallissa käytetään yhteisesti sekä aika- että taajuusresursseja usean ryhmän keilanmuodostusta suunniteltaessa.
Laajennuksena yhteistoiminnalliselle esikoodaukselle, väitöskirjassa käsitellään myös keilanmuodostusta pilvipohjaisessa radioliityntäverkkoarkkitehtuurissa. Keilanmuodostajat suunnitellaan keskitetysti, kvantisoidaan ja lähetetään datan mukana tukiasemille käyttäen runkoverkkoyhteyttä. Koska käyttäjiä voidaan palvella usealta tukiasemalta, keilanmuodostussuunnittelu muuttuu ei-konveksiksi kombinatoriseksi ongelmaksi. Toisin kuin olemassa olevissa ratkaisuissa, ehdotettu malli sisällyttää käyttäjien datan lisäksi keilanmuodostajien resursoinnin tarpeen runkoverkkoon. Tukiaseman antennien määrän lisääntyessä, keilanmuodostajien osuus runkoverkon käyttöasteesta kasvaa suureksi. Jotta keilanmuodostajien aiheuttamaa ylimääräistä tiedonsiirtotarvetta voitaisiin minimoida, esitellään kaksi tekniikkaa: kvantisointitarkkuuden muunteleminen sekä lähetykseen käytettävien aktiivisten antennien määrän vähentäminen.
Lopuksi, jotta yhdistetyn tila-taajuussuunnittelun aiheuttamaa kompleksisuutta saataisiin vähennettyä, ehdotetaan kaksivaiheista menetelmää. MU-MIMO skedulointialgoritmin avulla etsitään ensin alijoukko käyttäjiä jokaiselle skedulointilohkolle. Esikooderit suunnitellaan vain valituille käyttäjille, mikä vähentää kompleksisuutta, heikentämättä suorituskykyä kuitenkaan olennaisesti. Poiketen nolla-avaruuteen perustuvista tekniikoista, esitetään yksinkertainen vektoriprojektioihin perustuva skeduleri. Kaikkien skedulerien reaaliaikasuorituskykyä on arvioitu toteuttamalla ne ohjelmoitavilla Xilinx ZYNQ-ZC702 system-on-chip (SoC) ja TI TCI6636K2H moniydinalustoilla.
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BRUKSANVISNING TILL DRIFT OCH UNDERHÅLL AV EN EMBALLERINGSMASKIN VID SCA / User manual for operation and maintenance of packaging machine at SCAKotikawatte, Yoheena January 2021 (has links)
Materialet i rapporten är 10% av det totala materialet som presenterats till SCA, de viktigaste resultaten redovisas i rapporten. Vid SCA:s sågverk Rundvik i Nordmaling finns en automatiserad emballeringsmaskin. Ingen bra anvisning för bruk/drift och underhåll för maskinen finns, vilket har gjort det svårt för personalen att hantera den. Syftet med detta arbete var att kartlägga maskinens delar, funktioner och därefter framta en bruksanvisning. Detta gjordes genom att först kartlägga placeringen av maskinens axlar samt dess funktioner. Därefter intervjuades personalen på hyvleriet för att reda ut svårigheter och problem med maskinen. En problemlösning som löser de mest förekommande felen har framställts. En underhållsplan har tagits fram för att underlätta underhåll av maskinen. En offert på en programuppdatering har skickats till maskinprogrammerare. En offert gällande en säkerhetsanordning till maskinen har skickats till maskintillverkare. Resultatet är en fullt användbar, enkelt läsbar bruksanvisning. Syftet har inte fullföljts helt då operatör inte hunnit testa instruktionerna. / The material in the report is 10% of the total material presented to SCA, the most important results are reported here. At SCA's sawmill Rundvik in Nordmaling, there is an automated packaging machine. There is no good user manual for use/operation and maintenance of the machine, which has made it difficult for the staff to handle it. The purpose of this work has been to map the machine's parts, functions and then produce a user manual. This was done by first mapping the location of the machine's axles and its functions. The staff at the planer were then interviewed to sort out difficulties and problems with the machine. A problem solution that solves the most common errors has been produced. A maintenance plan has been developed to facilitate maintenance of the machine. A quote for a software update has been sent to the machine programmer. A quote regarding a safety device for the machine has been sent to the machine manufacturer. The result is a fully usable, easy-to-read user manual. The purpose has not been fully fulfilled as the operator has not had time to test the instructions.
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Uso da cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial para determinação do perfil de eicosanoides em plasma após estimulação: comparação entre pacientes com anemia falciforme e indivíduos saudáveis / High performance liquid chromatography coupled with tandem mass spectrometry to investigate eicosanoid profile in peripheral blood after stimulation: comparison between sickle cell anemia patients with healthy individualsMeirelles, Alyne Fávero Galvão 24 March 2016 (has links)
Os eicosanoides, produtos do metabolismo do ácido araquidônico, apresentam papel importante na homeostasia e na patogênese de diversas doenças humanas. A biossíntese desses compostos pode ser estimulada por agentes farmacológicos como ionóforos e inibidores da Ca2+-ATPase, e também por agonistas naturais como o formil-metionil-leucil-fenialanina (fMLP). Considerando os interesses em avaliar e comparar o perfil de mediadores lipídicos, como os leucotrienos (LTs), as prostaglandinas (PGs), os ácidos epoxieicosatrienoicos (EETs), os ácidos dihidroxitetraenoicos (DiHETEs) e os ácidos hidroxieicosatetraenoicos (HETEs), na saúde e na doença, o objetivo deste trabalho foi padronizar um método analítico para determinar do perfil de eicosanoides em plasma humano após estimulação do sangue total, e assim observar diferenças entre indivíduos saudáveis e doentes. Dessa forma, um método por cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial (HPLC-MS/MS) foi validado para quantificação de 22 eicosanoides em plasma de indivíduos saudáveis. A análise por HPLCMS/ MS foi realizada em modo negativo pelo modo de varredura por monitoramento de reações múltiplas (MRM). A linearidade do método apresentou coeficiente de correlação (r) maior que 0,98 para todos os eicosanoides analisados. A precisão e exatidão intra e inter-ensaios tiveram desvio padrão e erro relativo menores que 15%, exceto para o limite inferior de quantificação cujos valores foram menores que 20%. Para estimulação das células do sangue total, quatro estímulos (fMLP, ionomicina, A23187 e tapsigargina) foram utilizados. A análise estatística mostrou que o A23187 e a tapsigargina foram os estímulos mais potentes na indução da produção de eicosanoides. Em seguida, comparamos o perfil de eicosanoides em amostras de plasma de indivíduos saudáveis com pacientes com anemia falciforme (AF), em tratamento com hidroxiureia (HU) ou transfusão sanguínea crônica. Os resultados demonstraram que o método é preciso para determinação de diferenças entre os pacientes e indivíduos saudáveis quanto à produção dos mediadores lipídicos 5-HETE, 12-HETE, LTB4, LTE4, TXB2 e PGE2. Portanto, nosso método analítico é sensível, específico e reprodutível para identificar e quantificar diferenças no perfil de eicosanoides em amostras de sangue estimuladas in vitro, e poderá contribuir para o estabelecimento do perfil de mediadores lipídicos em diferentes doenças inflamatórias e infecciosas. / Eicosanoids, products from arachidonic acid metabolism, play an important role in the homeostasis and in the pathogenesis of various human diseases. Pharmacological agents such as Ca2+ ionophores and Ca2+-ATPase inhibitors, as well as natural agonists such as fMet-leu-Phe (fMLP) can stimulate eicosanoid biosynthesis. Considering the interests in evaluate and compare the profile of lipid mediators, as leukotriens (LTs), prostaglandins (PGs), epoxyeicosatrienoic acids (EETs), dihydroxytetraenoic acids (DiHETEs) and hydroxyeicosatetraenoic acids (HETEs), in healthy and disease, the aim of this work was to standardize a method to determine the eicosanoid profile of human plasma samples after whole blood stimulation, and to assess differences between healthy and sick individuals. For this purpose, a liquid chromatographytandem mass spectrometry (LC-MS/MS) method was validated for the quantification of 22 eicosanoids using human plasma from healthy volunteers. In addition, we optimized a method for the stimulation of eicosanoids in human whole blood. LC-MS/MS analyses were performed by negative electrospray ionization and multiple reaction monitoring. An assumption of linearity resulted in a regression coefficient > 0.98 for all eicosanoids tested. The mean intra-assay and inter-assay accuracy and precision values had relative standard deviations and relative errors of < 15%, except for the lower limit of quantification, where these values were < 20%. For whole blood stimulation, four stimuli (fMLP, ionomycin, A23187, and thapsigargin) were used. Results of the statistical analysis showed that A23187 and thapsigargin were potent stimuli to induce the production of eicosanoids. We next compared the eicosanoid profiles of healthy volunteers to those of patients with sickle cell anemia (SCA) under treatment with hydroxyurea (HU) or after chronic red blood cell (RBC) transfusion. The results indicate that the method was sufficient to find a difference between lipid mediators released in whole blood of SCA patients compared to healthy subjects for 5-HETE, 12-HETE, LTB4, LTE4, TXB2, and PGE2. In conclusion, our analytical method is sensitive, specific and reproducible for indentify and quantify changes in eicosanoid profiles in whole blood stimulated in vitro, which can contribute to establishing the eicosanoid profiles associated with different inflammatory and infectious diseases.
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