367 research outputs found
Varicocoelectomy in adolescents: laparoscopic versus open high ligation technique
Background: Treatment of varicocoele is aimed at eliminating the retrograde reflux of venous blood through the internal spermatic veins. The purpose of this investigation was to compare laparoscopic varicocoelectomy (LV) with open high ligation technique in the adolescent population. Materials and Methods: We retrospectively evaluated 33 adolescents who underwent varicocoelectomy at our paediatric hospital, between May 2004 and September 2008. Patients were divided into two groups depending on the technique: those who had an LV and those submitted to an open varicocoelectomy (OV). We analysed side, age of surgery, follow-up period and the incidence of recurrence/persistence, hydrocoele formation and wound complication. Results: There were 24 patients in the LV group and 9 in the OV group. All varicocoeles were in the left side. Mean age was 12 years in both groups. Mean follow-up time was 32 months for the LV group and 38 months for the OV group (P = 0.49). There was no significant difference in the incidence of hydrocoele in both the groups (25% versus 22%, P = 0.626). There was no recurrence/persistence on the LV group, while in the OV group there were three cases (P = 0.015). Conclusion: LV seems more efficient than open high ligation technique in the treatment of adolescents«SQ» varicocoeles. Larger series are necessary to draw more reliable conclusions
Evaluating certification protocols in the partial database state machine
Partial replication is an alluring technique to ensure the reliability of very large and geographically distributed databases while, at the same time, offering good performance. By correctly exploiting access locality most transactions become confined to a small subset of the database replicas thus reducing processing, storage access and communication overhead associated with replication. The advantages of partial replication have however to be weighted against the added complexity that is required to manage it. In fact, if the chosen replica configuration prevents the local execution of transactions or if the overhead of consistency protocols offsets the savings of locality, potential gains cannot be realized. These issues are heavily dependent on the application used for evaluation and render simplistic benchmarks useless. In this paper, we present a detailed analysis of Partial Database State Machine (PDBSM) replication by comparing alternative partial replication protocols with full replication. This is done using a realistic scenario based on a detailed network simulator and access patterns from an industry standard database benchmark. The results obtained allow us to identify the best configuration for typical on-line transaction processing applications.União Europeia - GORDA Project (FP6-IST/004758)
Group-based replication of on-line transaction processing servers
Several techniques for database replication using group communication have recently been proposed, namely, the Database State Machine, Postgres-R, and the NODO protocol. Although all rely on a totally ordered multicast for consistency, they differ substantially on how multicast is used. This results in different performance trade-offs which are hard to compare as each protocol is presented using a different load scenario and evaluation method. In this paper we evaluate the suitability of such protocols for replication of On-Line Transaction Processing (OLTP) applications in clusters of servers and over wide area networks. This is achieved by implementing them using a common infra-structure and by using a standard workload. The results allows us to select the best protocol regarding performance and scalability in a demanding but realistic usage scenario.Projecto STRONGRE (POSI/CHS/41285/2001)
financiado pela Fundação para a Ciência e a Tecnologia (FCT)
Testing the dependability and performance of group communication based database replication protocols
Database replication based on group communication systems has recently been proposed as an efficient and resilient solution for large-scale data management. However, its evaluation has been conducted either on simplistic simulation models, which fail to assess concrete implementations, or on complete system implementations which are costly to test with realistic large-scale scenarios. This paper presents a tool that combines implementations of replication and communication protocols under study with simulated network, database engine, and traffic generator models. Replication components can therefore be subjected to realistic large scale loads in a variety of scenarios, including fault-injection, while at the same time providing global observation and control. The paper shows first how the model is configured and validated to closely reproduce the behavior of a real system, and then how it is applied, allowing us to derive interesting conclusions both on replication and communication protocols and on their implementationsFundação para a Ciência e a Tecnologia (FCT) - Project STRONGREP (POSI/CHS/41285/2001)
A hybrid modular multilevel converter with reduced full-bridge submodules
A hybrid modular multilevel converter (MMC) with reduced full-bridge (FB) submodules (SMs) is proposed, where a high voltage rating half-bridge (HB) based MMC is connected in series with a low voltage rating FB-MMC in parallel with a fault breaking circuit on its DC side. Unlike conventional hybrid MMCs with mixed HB and FB SMs, the proposed topology uses the DC capacitor in the fault breaking circuit to block DC faults, while the FB-MMC only commutates the fault current from the FB-MMC to the fault breaking circuit. Thus, the proposed converter only requires around 10%-20% FB SMs, leading to reduced capital cost and losses compared to typical hybrid MMC. The optimal ratio of the FB-MMC and HB-MMC is assessed and comparative studies show superiority of the proposed topology over other alternatives. A case study with 10% FB SMs demonstrates the validity of the proposed hybrid MMC for DC fault blocking and post-fault system restart
Estudo higroscópico da polpa em pó do fruto da pitaya (Hylocereus costaricencis) em diferentes concentrações de maltodextrina
Pitaya is a nutritious fruit with low caloric value and high antioxidant power due to the presence of betalains, nitrogenous and water-soluble pigments similar to anthocyanins and flavonoids, with different chemical structures. This article presents a systematic Pitaya pulp powder dye study regarding its hygroscopic behavior. The experiments were conducted by adding maltodextrin in the proportions of 10, 20, 30, 40, 50 and 100%. The different percentages allowed a progressive incremental number of solids in Pitaya dye and a more thorough pure powder dye analysis. The bleaching process was carried out in all samples and, subsequently, the samples were lyophilized for 48 hours to increase stability through the reduction of water activity. This is done to minimize enzymatic chemical reactions, which occur during material storage, and to augment product lifespan. Therefore, by the construction of adsorption and moisture desorption isotherms at 25 °C in different concentrations of maltodextrin, the hygroscopicity of Pitaya dye was analyzed as well as the applicability of mathematical models in the prediction of product isotherms. The obtained isotherms were sigmoidal, classified as type II and the GAB model was proved more suitable to be used in the prediction of dye sorption isotherms.Neste trabalho estudou-se o corante da polpa de pitaya em pó e seu comportamento higroscópico. A pitaya é um fruto nutritivo com baixo valor calórico e alto poder antioxidante devido à presença de betalaínas, pigmentos nitrogenados e hidrossolúveis semelhantes ao grupo das antocianinas e flavonóides, com estruturas químicas diferentes. Os experimentos foram realizados adicionando maltodextrina no corante de pitaya nas proporções de 10, 20, 30, 40, 50 e 100%, visando aumentar a quantidade de sólidos no corante e analisando-se também o corante em pó puro. Em todas as amostras foi realizado o processo de branqueamento e, em seguida, a liofilização por 48 horas, aumentando, assim, a estabilidade por meio da redução da atividade de água, de modo a minimizar reações químicas enzimáticas que ocorrem durante a armazenagem do material, contribuindo para o acréscimo da vida útil do produto. Portanto, por meio da construção de isotermas de adsorção e dessorção de umidade a 25 °C em diferentes concentrações de maltodextrina analisou-se a higroscopicidade do corante de pitaya, assim como, a aplicabilidade de modelos matemáticos na predição das isotermas do produto. As isotermas obtidas foram sigmoidais, classificadas como do tipo II e o modelo de GAB mostrou-se mais adequado para ser utilizado na predição das isotermas de sorção do corante
A Pitaya (hylocereus costaricencis) pulp powder hygroscopic study in different maltodextrin concentrations
Neste trabalho estudou-se o corante da polpa de pitaya em pó e seu comportamento higroscópico. A pitaya é um fruto nutritivo com baixo valor calórico e alto poder antioxidante devido à presença de betalaínas, pigmentos nitrogenados e hidrossolúveis semelhantes ao grupo das antocianinas e flavonóides, com estruturas químicas diferentes. Os experimentos foram realizados adicionando maltodextrina no corante de pitaya nas proporções de 10, 20, 30, 40, 50 e 100%, visando aumentar a quantidade de sólidos no corante e analisando-se também o corante em pó puro. Em todas as amostras foi realizado o processo de branqueamento e, em seguida, a liofilização por 48 horas, aumentando, assim, a estabilidade por meio da redução da atividade de água, de modo a minimizar reações químicas enzimáticas que ocorrem durante a armazenagem do material, contribuindo para o acréscimo da vida útil do produto. Portanto, por meio da construção de isotermas de adsorção e dessorção de umidade a 25 °C em diferentes concentrações de maltodextrina analisou-se a higroscopicidade do corante de pitaya, assim como, a aplicabilidade de modelos matemáticos na predição das isotermas do produto. As isotermas obtidas foram sigmoidais, classificadas como do tipo II e o modelo de GAB mostrou-se mais adequado para ser utilizado na predição das isotermas de sorção do corante.Pitaya is a nutritious fruit with low caloric value and high antioxidant power due to the presence of betalains, nitrogenous and water-soluble pigments similar to anthocyanins and flavonoids, with different chemical structures.
This article presents a systematic Pitaya pulp powder dye study regarding its hygroscopic behavior. The experiments were conducted by adding maltodextrin in the proportions of 10, 20, 30, 40, 50 and 100%. The different percentages allowed a progressive incremental number of solids in Pitaya dye and a more thorough pure powder dye analysis. The bleaching process was carried out in all samples and, subsequently, the samples were lyophilized for 48 hours to increase stability through the reduction of water activity. This is done to minimize enzymatic chemical reactions, which occur during material storage, and to augment product lifespan. Therefore, by the construction of adsorption and moisture desorption isotherms at 25 °C in different concentrations of maltodextrin, the hygroscopicity of Pitaya dye was analyzed as well as the applicability of mathematical models in the prediction of product isotherms. The obtained isotherms were sigmoidal, classified as type II and the GAB model was proved more suitable to be used in the prediction of dye sorption isotherms.Facultad de Ciencias Agrarias y Forestale
Aspectos anatomohistológicos da sutura na língua com poliglecaprone 25, náilon e categute simples em ratas
The present study analyzed the reaction of 4-0 nylon thread, 4-0 simple categut and 4-0 polyglecaprone 25 in suture of tongue of the rats. Eight wistar female rats were used in each group of the rats. The animal under anesthetic, made incision of 1.0 cm, glossotomy in the medial line tongue. In the groups of wires 4- 0 nylon, 4-0 simple categut and 4-0 polyglecaprone 25 groups the glossoraphia with separate points has been performed. The resurgery followed the chronogram of 3, 6, 12 and 24 days under the same technical surgical to make the glossectomy and to send for to histhological analysis. The surgical procedure was evaluated dehiscense, exudate and edema.The three groups showed similar reaction. In the third DAO (Days-After-Operation) it was found the wire without granulation. In the sixth DAO it was found the rest of ulcer and scab in all groups. In the tenth second showed completed scar in group nylon and incompleted in the groups simple categut and polyglecaprone 25. In the twentieth-fouth DAO the scab was completed in all groups. All wires used showed inflammatory reaction with ulcer, without granulation. The use of simple categut is advisable, because in sixth day-after-operation the thread was absorbed.O presente estudo analisou a reação aos fios de náilon, categute simples e poliglecaprone 25 na sutura da língua das ratas. Foram utilizadas oito ratas wistar fêmeas em cada grupo. Realizou-se, no animal sob anestesia, uma incisão (glossotomia) de 01 cm. na linha mediana da língua No grupo do náilon 4-0, categute simples 4-0 e poliglecaprone 25 4-0, foi feita a glossorrafia com pontos separados. A reoperação seguiu o cronograma de 3, 6, 12 e 24 dias, sob a mesma técnica operatória, para fazer a glossectomia, com encaminhamento para a análise histológica. O procedimento cirúrgico foi avaliado quanto a deiscência, exsudato e edema. Os três grupos apresentaram reações semelhantes. No 3° DPO, encontrou- se o fio sem granuloma; no 6° DPO, constatou-se a existência de resto de úlcera e crosta em todos os grupos; o 12° DPO mostrou cicatriz completa no GN e incompleta nos GSC e PGP; e no 24° DPO, a cicatrização foi completa em todos os grupos. Conclui-se que todos os fios utilizados apresentaram reação inflamatória com ulcerações, sem granulomas. Aconselha-se o uso do categute simples, pois, no 6° DPO, o fio foi absorvido
Uma nova matéria-prima na produção de biodiesel: sementes do pinhão-roxo
Biodiesel is an alternative fuel that is produced through oil plants or animal fat. It is a renewable energy source, with biodegradable characteristics, to emit less pollutant than diesel. Thus, this work aims to show the production of biodiesel from the purple-pinion (Jatropha gossypiifolia L.) seeds. In addition to the synthesis, the physical-chemical characterization of both the raw material and the final product was carried out. The biodiesel synthetic route was performed by the basic catalytic transesterification reaction, using potassium hydroxide (KOH) in the presence of methanol (CH3OH) in the molar ratio of 1: 3 (oil: methanol). As a result, it was observed that the mass conversion of the biodiesel was 22.05 g. The physical-chemical analyzes carried out were acid index of 0.106 mgKOH / g, according to ANP technical resolution. The peroxide index of 1.03 meqO2 / kg, the kinematic viscosity of 20 ° C to 40 ° C, obtained was 6.455 mm2/s and 3.5343 mm2/s, the values are close to the ANP technique resolutions. Stability was 0.26 hours, and the biodiesel burning test was executed for approximately 3 hours. Therefore, there is a high viability of biodiesel production through the purple pinion seeds.O biodiesel é uma alternativa de combustível que é produzido através das plantas oleaginosas ou gordura animal. É fonte de energia renovável, com características biodegradáveis, por emitir menos poluentes que o diesel. Assim, este trabalho tem como objetivo mostrar a produção de biodiesel a partir das sementes pinhão-roxo (Jatropha gossypiifolia L.). Além da síntese, foi realizado a caracterização físico-química, tanto da matéria prima, como o produto final. A rota sintética do biodiesel foi realizada pela reação de transesterificação via catalise básica, utilizando o hidróxido de potássio (KOH) na presença de metanol (CH3OH) na razão molar de 1:3 (óleo: metanol). Como resultado, observou-seque a conversão em massa do biodiesel foi 22,05 g. As análises físico-químicas realizadas foram: índice acidez de 0,106 mgKOH/g, estão de acordo com resolução técnica da ANP. O índice peróxido de 1,03 meqO2/Kg, a viscosidade cinemática de 20°C a 40°C, obtida foi de 6,455 mm2/s e 3,5343 mm2/s, os valores estão próximos das resoluções de técnica da ANP, a estabilidade oxidativa foi 0,26 horas, e o teste de queima do biodiesel durou aproximadamente 3 horas. Portanto, existe uma alta viabilidade de produção do biodiesel através das sementes de pião roxo
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