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Sample records for arame tubular para

  1. Comparação do desempenho operacional e das características do cordão na soldagem com diferentes arames tubulares Comparison of operational performance and bead characteristics when welding with different tubular wires

    Directory of Open Access Journals (Sweden)

    Cícero Murta Diniz Starling

    2009-03-01

    Full Text Available Este trabalho objetivou o estudo comparativo das características do cordão produzido por arames tubulares nacionais dos tipos rutílico (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M, básico (ASME SFA-5.20: E71T-5/E71T-5M e "metal cored" (ASME SFA-5.18: E70C3M com 1,2 mm, destinados à soldagem de aços estruturais de baixo e médio teor de carbono. Realizaram-se testes de soldagem, na posição plana, sobre chapas grossas (espessura de 12 mm de aço carbono comum de baixo carbono utilizando-se uma fonte operando no modo "tensão constante" e com monitoração dos sinais de corrente e tensão do arco e velocidade de alimentação (fusão do arame. Variaram-se, na soldagem com cada tipo de arame tubular, a composição do gás de proteção (75%Ar-25%CO2 e 100%CO2 e a velocidade de alimentação do arame (7 e 9 m/min. Os demais parâmetros foram mantidos fixos, incluindo-se a polaridade do eletrodo (CC+ e os comprimentos energizado do eletrodo (16 mm e do arco (3,5 mm. Para os diferentes arames tubulares, avaliaram-se comparativamente as principais características do cordão, incluindo a sua geometria (penetração, reforço, largura, área fundida, área depositada e diluição, presença de descontinuidades, microestrutura e dureza. Levantaram-se as condições operacionais associadas a um cordão com características adequadas à soldagem de chapas grossas de aços estruturais.This paper compares the bead characteristics of welds deposited of carbon steel tubular wires. Three tubular wires of 1.2 mm produced in Brazil were used: rutilic (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M, basic (ASME SFA-5.20: E71T-5/E71T-5M and metal cored (ASME SFA-5.18: E70C-3M. Welding trials were performed in downhand position on thick (12 mm low-carbon steel plates using a constant voltage power supply. Welding current and voltage, and wire feed rate were monitored in all trials. For each tubular wire type, the shielding gas composition (75%Ar-25%CO2 and 100%CO2 and wire

  2. Caracterização do cordão na soldagem FCAW com um arame tubular "metal cored" Bead characterization on FCAW welding of a metal cored tubular wire

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    Cícero Murta Diniz Starling

    2011-09-01

    Full Text Available Este trabalho objetivou o estudo do efeito de algumas condições operacionais nas características do cordão produzido por um arame tubular "metal cored" (ASME SFA-5.18: E70C-3M de fabricação nacional com 1,2 mm de diâmetro, destinado à soldagem de aços carbono comuns estruturais de baixo e médio teor de carbono. Realizaram-se testes de soldagem, na posição plana, sobre chapas grossas (espessura de 12 mm de aço de baixo carbono utilizando-se uma fonte operando no modo "tensão constante" e com monitoração dos sinais de corrente e tensão do arco e velocidade de alimentação (fusão do arame. Variaram-se a composição do gás de proteção (75%Ar-25%CO2 e 100%CO2, a polaridade do eletrodo (positiva e negativa e a velocidade de alimentação do arame (7 e 9 m/min. Os demais parâmetros de soldagem foram mantidos fixos, incluindo-se os comprimentos energizado do eletrodo (16 mm e do arco (3,5 mm. Avaliaram-se os efeitos das condições operacionais nas principais características do cordão incluindo a sua geometria (penetração, reforço, largura, área fundida, área depositada e diluição, presença de descontinuidades, microestrutura e dureza. Levantaram-se, para o arame "metal cored", as condições operacionais de maior produtividade (maior taxa de deposição associadas a um cordão com características adequadas à soldagem de chapas grossas de aços estruturais.This work evaluates the relationship between operational conditions and the characteristics of weld beads deposited with a 1.2 mm produced in Brazil metal cored tubular wire (ASME SFA-5.18: E70C-3M. Welding trials were performed in downhand position on 12mm thick low-carbon steel plates using a constant voltage power supply. Welding current and voltage, and wire feed rate were monitored in all trials. While the shielding gas composition (75%Ar-25%CO2 and 100%CO2, wire polarity, and wire feed rate (7 and 9 m/min were changed, other process variables, including

  3. Comparação do desempenho operacional e das caracter��sticas do cordão na soldagem com diferentes arames tubulares em polaridade negativa Comparison of operational performance and bead characteristics when welding with different tubular wires in negative polarity

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    Cícero Murta Diniz Starling

    2011-12-01

    Full Text Available Este trabalho objetivou o estudo comparativo das características do cordão produzido por arames tubulares nacionais dos tipos rutílico (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M, básico (ASME SFA-5.20: E71T-5/E71T-5M e "metal cored" (ASME SFA-5.18: E70C-3M com 1,2 mm, destinados à soldagem de aços estruturais de baixo e médio teor de carbono. Realizaram-se testes de soldagem com o eletrodo na polaridade negativa (CC-, na posição plana, sobre chapas grossas (espessura de 12 mm de aço carbono comum de baixo carbono utilizando-se uma fonte operando no modo "tensão constante" e com monitoração dos sinais de corrente e tensão do arco e velocidade de alimentação (fusão do arame. Variaram-se, na soldagem com cada tipo de arame tubular, a composição do gás de proteção (75%Ar-25%CO2 e 100%CO2 e a velocidade de alimentação do arame (7 e 9 m/min. Os demais parâmetros foram mantidos fixos, incluindo-se, além da polaridade negativa do eletrodo, os comprimentos energizado do eletrodo (16 mm e do arco (3,5 mm. Para os diferentes arames tubulares, avaliaram-se comparativamente as principais características do cordão, incluindo a sua geometria (penetração, reforço, largura, área fundida, área depositada e diluição, presença de descontinuidades, microestrutura e dureza. Levantaram-se as condições operacionais associadas a um cordão com características adequadas à soldagem de chapas grossas de aços estruturais com a polaridade do eletrodo negativa.This paper compares the bead characteristics of welds deposited of carbon steel tubular wires. Three tubular wires of 1.2mm produced in Brazil were used: rutilic (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M, basic (ASME SFA-5.20: E71T-5/E71T-5M and metal cored (ASME SFA-5.18: E70C-3M. Welding trials were performed in downhand position on thick (12 mm low-carbon steel plates using a constant voltage power supply in negative wire polarity (CC-. Welding current and voltage, and wire feed rate

  4. Estudo comparativo da resistência ao desgaste abrasivo do revestimento de três ligas metálicas utilizadas na indústria, aplicadas por soldagem com arames tubulares Comparative study of the wear resistance of three metal cored wire welded coatings used in industry

    Directory of Open Access Journals (Sweden)

    Ricardo Vinícius de Melo Leite

    2009-12-01

    Full Text Available As ligas metálicas aplicadas por soldagem em superfícies, objetivando a proteção contra o desgaste e o conseqüente aumento da vida útil de peças e equipamentos, têm sido utilizadas em larga escala nas indústrias de bens de consumo e nos setores de mineração e sucroalcooleiro. O desgaste abrasivo em peças e equipamentos representa, nestas industriais, um dos principais fatores de depreciação de capital e uma importante fonte de despesas com manutenção. Para a aplicação do revestimento por soldagem, os arames tubulares têm sido uma alternativa cada vez mais viável, devido à sua alta produtividade e qualidade de solda, substituindo, em parte, o uso do eletrodo revestido. O objetivo deste trabalho é fazer um estudo comparativo da resistência ao desgaste abrasivo do revestimento aplicado por soldagem com arames tubulares autoprotegidos de três ligas metálicas utilizadas na indústria, uma do tipo Fe-Cr-C, outra do tipo Fe-Cr-C com adição de nióbio e boro e a terceira, do tipo Fe-Cr-C com adição de nióbio. Os revestimentos anti-desgaste, conhecidos como revestimento duro, foram aplicados em chapas de aço carbono, com os mesmos parâmetros e procedimentos de soldagem. Os corpos de prova foram obtidos por corte e retificação e foram submetidos a ensaios de desgaste abrasivo, em um abrasômero Roda de Borracha, conforme procedimento estabelecido pela norma ASTM G65-91. Os resultados obtidos demonstraram que a liga Fe-Cr-C com adição de Nióbio e Boro apresentou desempenho superior em relação ao desgaste abrasivo.The metal alloys deposited by welding on the components surface, with the objective of protection against wear and the consequent increase in the lifetime of parts and equipments, have been used extensively in the consumer products industry and sectors of Mining and Sugar & alcohol. The abrasive wear on parts and equipments represents one of the main depreciation factors of capital and the major source of

  5. Análise comparativa da geração de fumos entre arames maciços (GMAW e tubulares (FCAW Comparative analysis of fume generation between solid (GMAW and flux cored wires (FCAW

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    Regina Paula Garcia

    2010-06-01

    Full Text Available O processo GMAW (MIG/MAG é muito utilizado no meio industrial. Entretanto, este processo apresenta limitações quanto a ações metalúrgicas sobre a zona fundida e moldabilidde do cordão. O processo FCAW, por outro lado, por apresentar elementos fluxantes, consegue melhores resultados nestes aspectos, mas o fluxo pode ser um agente responsável por elevada emissão de fumos. Este trabalho teve por objetivo apresentar um estudo comparativo da geração de fumos entre o processo GMAW com transferência metálica por curto-circuito e o processo FCAW sob proteção gasosa, ambos com eletrodos de mesma classe de resistência mecânica (483 MPa de limite de ruptura e aplicação. Os experimentos foram realizados utilizando-se um coletor de fumos calibrado de acordo com norma. Os dois consumíveis foram avaliados sob uma proteção de 100% CO2 em dois níveis de corrente. O efeito do comprimento do arco e do uso de outra proteção (Ar+25% CO2 também foi avaliado. Para se possibilitar uma comparação próxima da realidade prática de cada consumível, procurou-se trabalhar com cada combinação arame/gás de proteção em condições apropriadas de distância bico de contato-peça e de regulagem de tensão. Fixou-se ainda o mesmo volume do cordão de solda por metro para cada nível de corrente, mantendo-se constante a relação entre a taxa de deposição e a velocidade de soldagem. Os resultados confirmam uma maior taxa de geração de fumos pelo processo FCAW (já esperado e que a taxa absoluta de fumos cresce com o aumento da corrente de soldagem, porém para processo GMAW analisado de forma relativa (em função da massa fundida isso não ocorre. Verificou-se que o efeito da corrente é mais significativo para o processo FCAW. O aumento do teor de CO2 elevou a taxa de geração de fumos apenas no processo FCAW, enquanto que a variação da tensão de arco não demonstrou qualquer efeito sobre esta.The GMAW (MIG /MAG process is widespread in

  6. Space and the Synchronic A-Ram

    CERN Document Server

    Berka, Alex V

    2010-01-01

    Space is a circuit oriented, spatial programming language designed to exploit the massive parallelism available in a novel formal model of computation called the Synchronic A-Ram, and physically related FPGA and reconfigurable architectures. Space expresses variable grained MIMD parallelism, is modular, strictly typed, and deterministic. Barring operations associated with memory allocation and compilation, modules cannot access global variables, and are referentially transparent. At a high level of abstraction, modules exhibit a small, sequential state transition system, aiding verification. Space deals with communication, scheduling, and resource contention issues in parallel computing, by resolving them explicitly in an incremental manner, module by module, whilst ascending the ladder of abstraction. Whilst the Synchronic A-Ram model was inspired by linguistic considerations, it is also put forward as a formal model for reconfigurable digital circuits. A programming environment has been developed, that inco...

  7. Avaliação do Uso de Curto-Circuito Controlado em Soldagens de Passes de Enchimento por MIG/MAG Duplo Arame

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    Dumitru Caimacan

    2015-03-01

    Full Text Available Neste trabalho foi realizada uma avaliação técnico-econômica do processo de soldagem MIG/MAG Duplo Arame para soldagens de passes de enchimento na posição plana, empregando o modo operacional Curto-Circuito Controlado (CCC no arame-seguidor, como forma de melhorar o controle da poça de fusão e reduzir respingos. A avaliação foi feita através de um estudo comparativo entre a técnica MIG/MAG Duplo Arame convencional (com uso da corrente pulsada em ambos os arames e uma combinação de Pulsado no arame-líder e CCC no arame-seguidor. Foram mantidos constantes os valores das correntes médias para cada arame, o volume de material depositado por unidade de comprimento de solda, o tipo e dimensão do chanfro e o arame, a composição do gás de proteção e a DBCP. Avaliou-se o acabamento superficial e a geometria dos cordões de soldas, a taxa e a eficiência de deposição e as velocidades limites de soldagem resultantes do uso de cada técnica. Os resultados mostram que o uso do modo CCC no arco seguidor aumenta levemente a capacidade de produção do processo, faz gerar menos respingos, melhora o acabamento do cordão, produz ZF e ZAC menores e ainda mantem similar envelope operacional (quanto à faixa de velocidades de soldagens úteis, o que são fatores positivos. Por outro lado, como desvantagem, o uso de CCC levou a cordões mais convexos e com uma penetração menor.

  8. Catastrophic ice lake collapse in Aram Chaos, Mars

    CERN Document Server

    Roda, Manuel; Zegers, Tanja E; Oosthoek, Jelmer H P

    2014-01-01

    Hesperian chaotic terrains have been recognized as the source of outflow channels formed by catastrophic outflows. Four main scenarios have been proposed for the formation of chaotic terrains that involve different amounts of water and single or multiple outflow events. Here, we test these scenarios with morphological and structural analyses of imagery and elevation data for Aram Chaos in conjunction with numerical modeling of the morphological evolution of the catastrophic carving of the outflow valley. The morphological and geological analyses of Aram Chaos suggest large-scale collapse and subsidence (1500 m) of the entire area, which is consistent with a massive expulsion of liquid water from the subsurface in one single event. The combined observations suggest a complex process starting with the outflow of water from two small channels, followed by continuous groundwater sapping and headward erosion and ending with a catastrophic lake rim collapse and carving of the Aram Valley, which is synchronous with ...

  9. Estudo comparativo da resistência ao desgaste abrasivo do revestimento de três ligas metálicas utilizadas na indústria, aplicadas por soldagem com arames tubulares Comparative study of the wear resistance of three metal cored wire welded coatings used in industry

    OpenAIRE

    Ricardo Vinícius de Melo Leite; Paulo Villani Marques

    2009-01-01

    As ligas metálicas aplicadas por soldagem em superfícies, objetivando a proteção contra o desgaste e o conseqüente aumento da vida útil de peças e equipamentos, têm sido utilizadas em larga escala nas indústrias de bens de consumo e nos setores de mineração e sucroalcooleiro. O desgaste abrasivo em peças e equipamentos representa, nestas industriais, um dos principais fatores de depreciação de capital e uma importante fonte de despesas com manutenção. Para a aplicação do revestimento por sold...

  10. A Case for Hydrothermal Gray Hematite in Aram Chaos

    Science.gov (United States)

    Catling, D. C.; Moore, J. M.

    2003-01-01

    The Thermal Emission Spectrometer (TES) on Mars Global Surveyor has detected deposits of coarsegrained, gray crystalline hematite in Sinus Meridiani, Aram Chaos, and Vallis Marineris [1]. Detailed features in the hematite spectral signature of the Sinus Meridiani region show that the spectrum is consistent with emission dominated by crystal c-faces of hematite, implying that the hematite is specular [2]. Gray specular hematite (also known as specularite ) is a particular gray crystalline form that has intergrown, hexagonal plates with a silvery metallic luster. We believe that the key to the origin of specularite is that it requires crystallization at temperatures in excess of about 100 C. In reviewing the occurrence of gray hematite on Earth, we find no exceptions to this warm temperature requirement [3]. Thermal crystallization on Mars could occur (1) as diagenesis at a depth of a few kilometers of sediments originally formed in lowtemperature waters, or (2) as direct precipitation from hydrothermal solution. Aram Chaos has unique chaotic terrain that offers more clues to the formation of the hematite than the relatively featureless flat terrain (as seen from orbit) of Sinus Meridiani. Aram Chaos provides the opportunity to look at a combination of TES data, Mars Orbiter Camera images, and Mars Orbiter Laser Altimeter (MOLA) topography. This combination of data suggests that high concentrations of hematite were formed in planar strata and have since been exposed by erosion of an overlying light-toned, caprock. Lesser concentrations of hematite are found adjacent to these strata at lower elevations, which we interpret as perhaps a lag deposit. The topography and the collapsed nature of the chaotic terrain favor a hydrothermally charged aquifer as the original setting where the hematite formed. An alternative sedimentary origin requires post-depositional burial to a depth of 3-5 km to induce thermally driven recrystallization of fine-grained iron oxides to coarse

  11. Modelo matemático para estructura tubular de edifico antisísmico

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    Mazzeo, Agustin

    1972-02-01

    Full Text Available This mathematical model was worked out when seeking a structural pattern for a building with a main steel structure, apt for the seismic circumstances of the city of Caracas. Of the various possibilities that were considered, it was decided the one which best met the conditions of the project involved the use of the so called external flexible tube, to withstand horizontal thrusts. The analysis of the space properties of the perimetral tube, through the use of a plane image of the structure, constitutes the mathematical model described in this article.El modelo matemático objeto del artículo fue desarrollado al estudiar la solución estructural para un edificio con estructura principal de acero, proyectado para las condiciones sísmicas de la ciudad de Caracas. De las varias alternativas analizadas, se concluyó que la que mejor permitía cumplir con las exigencias del proyecto consistía en utilizar como solución, para resistir los efectos horizontales, el sistema estructural conocido como tubo exterior flexible. El análisis de las características espaciales del tubo perimetral mediante el uso de una imagen plana de la estructura, constituye el modelo matemático que se describe en el artículo.

  12. Eletrodos positivos tubulares para baterias chumbo ácidas produzidas com material ativo nanométrico

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    Patrício R Impinnisi

    2011-01-01

    Full Text Available Conventional stationary lead acid batteries positive tubular plates have a specific capacity of about 120 Ah/kg. This value represents an active material utilization coefficient of 50%. The production of these plates includes some initial processes to generate the active PbO2 from a precursor material. In the present work it will be presented a proper and novel methodology to assemble tubular plates directely with nanometric powder of PbO2 particles. The utilization coefficient of these plates was about 80%, and they were able to endure more than 130 severe duty cycles. This high utilization coefficient is a higly desirable feature for electric vehicles batteries.

  13. Navegation system for tubular upper digestive tract Sistema de navegación tubular para vías digestivas altas

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    Camilo Andrés Rojas Cifuentes

    2013-03-01

    Full Text Available The present endoscopy is an uncomfortable experience because these instruments are great size and magnitude, generating feelings of discomfort to the patient during the operation. It’s designed a device to scale, allowing counteract this effect improving the mechanism of endoscopy, being this a more effective and flexible, compared with capsule endoscopy and endoscopy equipment present because will include a biopsy system for analyzing gastroenterological diseases or gastric cancers, with bluetooth communication for visualization of real-time space tract.La endoscopia actual es una experiencia incómoda ya que su instrumental es de gran tamaño y magnitud, generando sensación de molestia al paciente durante el manejo que realiza el especialista de los dispositivos que se operan en el proceso. Se diseña un dispositivo a escala, que permita contrarrestar tal efecto mejorando el mecanismo de endoscopia; siendo éste un sistema más efectivo y ágil, comparado con la cápsula endoscópica y el equipo actual, por lo cual incluirá un sistema de toma de biopsias para analizar enfermedades gastroenterológicas o cánceres, con comunicación Bluetooth para la visualización del espacio digestivo en tiempo real.

  14. Simulação numérica aplicada para avaliar o efeito da pré-polimerização no comportamento de reatores tubulares Numerical simulation to evaluate the effect from pre-polymerization on the behavior of tubular reactors

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    André L. Nogueira

    2007-09-01

    Full Text Available O presente estudo utiliza um modelo matemático fenomenológico para simular um sistema de polimerização contínuo em dois estágios. Este sistema é composto por um reator contínuo tipo tanque agitado (CSTR, para pré-polimerização do monômero (primeiro estágio, associado em série a um reator tubular para conduzir a reação até elevados valores de conversão (segundo estágio. Um modelo detalhado, considerando variações axiais e radiais, assim como operação não-isotérmica, foi utilizado para simular o comportamento do reator tubular em diferentes situações. Um modelo de caracterização também foi desenvolvido para fornecer estimativas do peso molecular médio e do índice de polidispersão do polímero. Os resultados mostram que reações de polimerização conduzidas em sistemas contínuos de dois estágios fornecem um polímero com propriedades menos heterogêneas do que um polímero obtido em um sistema reacional composto por apenas um reator tubular. Além disso, quanto maior a viscosidade da mistura reacional alimentada ao reator tubular, mais homogêneo é o polímero obtido.The present study uses a phenomenological model to simulate a continuous, two-stage polymerization process. This system is composed by a continuous stirred tank reactor (CSTR for monomer pre-polymerization (first stage, connected to a tubular reactor (second stage to carry out the reaction up to high conversion values. A comprehensive non-isothermal 2-D model (axial and radial variations was used to predict the tubular reactor behavior. A polymer characterization model was also developed to provide estimates of the polymer average molecular weight and polydispersity. According to the results, polymerization reactions carried out in a continuous two-stage system provide a polymer with less heterogeneous properties than the one obtained in a single tubular reactor. Besides, it is possible to produce a more homogeneous polymer increasing the viscosity

  15. Análise comparativa de envoltórios para drenos tubulares em condições de fluxo não-permanente Comparative analysis of envelopes for tubular drains under non-steady state flow conditions

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    Denise M. de Almeida

    2001-04-01

    Full Text Available Com esta pesquisa, objetivou-se avaliar a eficiência de envoltórios em drenos tubulares sob condições de fluxo não-permanente; para tanto, foram utilizados, em tanques de alvenaria, os envoltórios de geotêxteis XT-4, XT-2, bidim OP-30 e bidim OP-20, envelopes de brita no 1, com espessuras de 0,05, 0,10 e 0,15 m, além de um tratamento com ausência de envoltório. As variáveis-resposta utilizadas para se testar os tratamentos consistiram da lâmina drenada num tempo de 30 min, da massa de areia carreada após este tempo de drenagem e do desempenho hidráulico dos drenos, com base no cálculo da resistência de entrada ao fluxo e da relação entre vazão e carga hidráulica a 0,55 m da interface solo-dreno. As lâminas drenadas não diferiram estatisticamente a nível de 5% de probabilidade; no entanto, os geotêxteis bidim OP-20 e XT-4 mostraram-se, nesta ordem, como as melhores opções, face à análise de desempenho e se considerando os aspectos custo e facilidade de instalação. Quanto à análise da variável carreamento de areia, verificou-se a influência da espessura do envoltório ao se analisar os tratamentos com brita, além da opção das mantas, como excelente filtro. Os dados de resistência de entrada demonstraram a importância do uso de envoltórios ao se comparar o tratamento sem envoltório (r ent = 0,0102 d m-1 com o tratamento brita 0,15m (r ent = 0,0032 d m-1 cuja redução foi de 68,7%.The aim of the research was to evaluate the performance of eight types of envelopes installed around tubular drains in a horizontal tank model, with the treatments bidim OP-20, bidim OP-30, XT-2 and XT-4, 0.15, 0.10 and 0.05 m thick gravel and the treatment drain without a wrapper. The response-variables for the treatments used consisted of the depth of water drained in thirty minutes, the mass of sediment transported by the water during this same time interval and the hydraulic performance of the drains based on the entrance

  16. Análise numérica-experimental de treliças tubulares planas para coberturas padronizadas para grandes vãos Numerical and experimental analysis of tubular plane trusses for use in a standardized roof system with long span

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    Fábio Aurélio Samarra

    2012-12-01

    Full Text Available O objetivo desse trabalho foi desenvolver um sistema de cobertura metálica padronizado e modular, utilizando perfis tubulares laminados sem costura. Esse sistema se destina, principalmente, a coberturas de supermercados, shoppings etc., que necessitam de grandes áreas livres. Para se avaliar o comportamento estrutural desse sistema, foi construído, de maneira inédita no Brasil, um protótipo de 900 m², para testar o sistema construtivo idealizado e realizar ensaios com os carregamentos reais, nesse tipo de estrutura. Avaliando-se, então, o comportamento global da estrutura, com base em todos os resultados numéricos e experimentais obtidos, confirmou-se o comportamento previsto, no cálculo computacional, com o protótipo ensaiado.The purpose of this study is the comparison between experimental and numerical data of a roof system made of tubular steel sections. Such roof system is applied mainly for supermarkets, large stores and industries. To evaluate the structural behavior of this system, a 900m² prototype was built, - an unprecedented opportunity in Brazil to accomplish experimental tests with usual loads for this type of structure. Evaluating the behavior of the entire structure, with all the results obtained on experimental tests and numerical analysis, it was concluded that the prototype is in general accordance with the designed model in terms of stresses and displacement.

  17. Pipeline welding with Flux Cored and Metal Cored Wire; Soldagem de dutos com processos Arame Tubular e de Alma Metalica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Ubirajara Pereira da [ITW Soldagem Brasil Miller-Hobart, Sao Paulo, SP (Brazil)

    2003-07-01

    Different welding process like SMAW, Semi-Automatic FCAW Gas-shielded and Self-shielded and Mechanized GMAW-MAG with Solid Wire are suggested to weld Transmission Pipelines. Presently, the largest extensions of Transmission Pipelines under construction, are in China like Lines West-East, Zong-Wu, Shan-Jing Fuxian and some others, totalizing about 8.000 km, and all using Semi-Automatic Self Shielded Flux Cored Arc Welding Process. Also, several papers and magazines that covers Transmission Pipelines Welding, not frequently mention Operational aspects of the process and some other variables like environment and site geography. This presentation intends to cover some of the Operational aspects of the Flux Cored Arc Welding and GMAW-Metal Cored in order to give sufficient information for Construction, Engineering, Projects e Contractors so they can evaluate these Process against the SMAW or even Mechanized Systems, considering the Operation Factor, Efficiency and Deposition Rate. We will not cover operational details of the GMAW Mechanized Systems but only suggest that be evaluated the possibility to replace the GMAW-Solid Wire by the GMAW-Metal Cored Wire. (author)

  18. Modelado de un reactor tubular de lipasas inmovilizadas para la producción de glicerol y ácidos grasos a partir de aceites

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    Oddone, Sebastián

    2010-06-01

    Full Text Available Advances in the design of a bioreactor in the fats and oils industry have permitted the hydrolysis of triglycerides in mild conditions and improved productivity while avoiding the formation of unwanted byproducts. The present work develops a mathematical model that describes the hydrolytic activity of a tubular reactor with immobilized lipases for the production of glycerol and fatty acids from the oil trade. Runge Kutta’s numerical method of high order has been applied, considering that there is no accumulation of the substratum in the surface of the membrane, where the enzyme is. At the same time, different equations based on the kinetic model of Michaelis Mentens and the Ping-Pong bi-bi mechanism were examined. Experimental data in discontinuous systems are the basis for the development of the quantitative mathematical model that was used to simulate the process computationally. The obtained results allow for optimizing both the operative variables and the economic aspects of industrial processes.

    Los avances en el diseño de biorreactores en la industria de grasas y aceites permiten realizar la hidrólisis de triglicéridos en condiciones suaves, mejorando la productividad y evitando la formación de subproductos indeseables. En el presente trabajo se desarrolla un modelo matemático que describe la actividad hidrolítica de un reactor tubular con lipasas inmovilizadas para la producción de ácidos grasos a partir de aceites comerciales. Se aplico el método numérico de Runge Kutta de alto orden, considerando que no hay acumulación de sustrato en la superficie de la membrana, donde se encuentra la enzima. Además se analizaron distintas ecuaciones de velocidad de reacción basadas en la cinética de Michaelis-Menten y en un mecanismo de ping-pong bi-bi. Los datos experimentales en sistemas discontinuos forman la base del desarrollo del modelo matemático, empleado para simular el proceso computacionalmente. Los resultados

  19. Proximal renal tubular acidosis

    Science.gov (United States)

    Renal tubular acidosis - proximal; Type II RTA; RTA - proximal; Renal tubular acidosis type II ... are neutralized by alkaline substances, mainly bicarbonate. Proximal renal tubular acidosis (Type II RTA) occurs when bicarbonate ...

  20. Distal renal tubular acidosis

    Science.gov (United States)

    Renal tubular acidosis - distal; Renal tubular acidosis type I; Type I RTA; RTA - distal; Classical RTA ... blood and excreting it into the urine. Distal renal tubular acidosis (Type I RTA) is caused by ...

  1. Caracterização do cordão na soldagem FCAW com um srame tubular rutílico Bead characterization on FCAW welding of a rutilic tubular wire

    Directory of Open Access Journals (Sweden)

    Cícero Murta Diniz Starling

    2009-12-01

    Full Text Available Este trabalho objetivou o estudo do efeito de algumas condições operacionais nas características do cordão produzido por um arame tubular rutílico (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M de fabricação nacional com 1,2mm de diâmetro, destinado à soldagem de aços carbono comuns estruturais de baixo e médio teor de carbono. Realizaram-se testes de soldagem, na posição plana, sobre chapas grossas (espessura de 12mm de aço carbono comum de baixo carbono utilizando-se uma fonte operando no modo "tensão constante" e com monitoração dos sinais de corrente e tensão do arco e velocidade de alimentação (fusão do arame. Variaram-se a composição do gás de proteção (75%Ar-25%CO2 e 100%CO2, a polaridade do eletrodo (positiva e negativa e a velocidade de alimentação do arame (7 e 9m/min. Os demais parâmetros de soldagem foram mantidos fixos, incluindo-se os comprimentos energizado do eletrodo (16mm e do arco (3,5mm. Avaliaram-se os efeitos das condições operacionais nas principais características do cordão incluindo a sua geometria (penetração, reforço, largura, área fundida, área depositada e diluição, presença de descontinuidades, microestrutura e dureza. Levantaram-se, para o arame rutílico, as condições operacionais de maior produtividade (maior taxa de deposição associadas a um cordão com características adequadas à soldagem de chapas grossas de aços estruturais.This paper studies the effect of operational conditions on bead shape characteristics in FCA welding with a Brazilian made wire with rutilic flux (ASME SFA-5.20: E71T-1/E71T-9/E71T-9M of 1.2mm diameter. Bead-on-plate downhand welding trials were performed on 12mm thick low carbon steel plates with a constant voltage power supply. A digital data logging system was used to measure the welding current and voltage, and wire feed rate. While the shielding gas composition (75%Ar-25%CO2 and 100%CO2, wire polarity and feed rate (7 and 9m/min were varied

  2. Tubular Coupling

    Science.gov (United States)

    Rosenbaum, Bernard J. (Inventor)

    2000-01-01

    A system for coupling a vascular overflow graft or cannula to a heart pump. A pump pipe outlet is provided with an external tapered surface which receives the end of a compressible connula. An annular compression ring with a tapered internal bore surface is arranged about the cannula with the tapered internal surface in a facing relationship to the external tapered surface. The angle of inclination of the tapered surfaces is converging such that the spacing between the tapered surfaces decreases from one end of the external tapered surface to the other end thereby providing a clamping action of the tapered surface on a cannula which increases as a function of the length of cannula segment between the tapered surfaces. The annular compression ring is disposed within a tubular locking nut which threadedly couples to the pump and provides a compression force for urging the annular ring onto the cannula between the tapered surfaces. The nut has a threaded connection to the pump body. The threaded coupling to the pump body provides a compression force for the annular ring. The annular ring has an annular enclosure space in which excess cannula material from the compression between the tapered surfaces to "bunch up" in the space and serve as an enlarged annular ring segment to assist holding the cannula in place. The clamped cannula provides a seamless joint connection to the pump pipe outlet where the clamping force is uniformly applied to the cannula because of self alignment of the tapered surfaces. The nut can be easily disconnected to replace the pump if necessary.

  3. Modeling of an immobilized lipase tubular reactor for the production of glycerol and fatty acids from oils; Modelado de un reactor tubular de lipasas inmovilizadas para la produccion de glicerol y acidos grasos a partir de aceites

    Energy Technology Data Exchange (ETDEWEB)

    Oddone, S.; Grasselli, M.; Cuellas, A.

    2010-07-01

    Advances in the design of a bioreactor in the fats and oils industry have permitted the hydrolysis of triglycerides in mild conditions and improved productivity while avoiding the formation of unwanted byproducts. The present work develops a mathematical model that describes the hydrolytic activity of a tubular reactor with immobilized lipases for the production of glycerol and fatty acids from the oil trade. Runge Kuttas numerical method of high order has been applied, considering that there is no accumulation of the substratum in the surface of the membrane, where the enzyme is. At the same time, different equations based on the kinetic model of Michaelis Mentens and the Ping-Pong bi-bi mechanism were examined. Experimental data in discontinuous systems are the basis for the development of the quantitative mathematical model that was used to simulate the process computationally. The obtained results allow for optimizing both the operative variables and the economic aspects of industrial processes. (Author)

  4. Modelado de un reactor tubular de lipasas inmovilizadas para la producción de glicerol y ácidos grasos a partir de aceites

    OpenAIRE

    Oddone, Sebastián; Grasselli, Mariano; Cuellas, Anahí

    2010-01-01

    Advances in the design of a bioreactor in the fats and oils industry have permitted the hydrolysis of triglycerides in mild conditions and improved productivity while avoiding the formation of unwanted byproducts. The present work develops a mathematical model that describes the hydrolytic activity of a tubular reactor with immobilized lipases for the production of glycerol and fatty acids from the oil trade. Runge Kutta’s numerical method of high order has been applied, considering that ther...

  5. Reliability of Tubular Joints

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    In this paper the preliminary results obtained by tests on tubular joints are presented. The joints are T-joints and the loading is static. It is the intention in continuation of these tests to perform tests on other types of joints (e.g. Y-joints) and also with dynamic loading. The purpose...... of the test is partly to obtain empirical data for the ultimate load-carrying capacity of tubular T-joints and partly to obtain some experience in performing tests with tubular joints. It is well known that tubular joints are usually designed in offshore engineering on the basis of empirical formulas obtained...

  6. Aram Dorsum, Candidate ExoMars Rover Landing Site: a Noachian Inverted Fluvial Channel System in Arabia Terra Mars

    Science.gov (United States)

    Balme, Matthew; Grindrod, Peter; Sefton-Nash, Elliot; Davis, Joel; Gupta, Sanjeev; Fawdon, Peter

    2016-04-01

    Much of Mars' Noachian-aged southern highlands is dissected by systems of fluvial channels and valleys > 3.7 Ga in age. Arabia Terra, lying between the southern highlands and the northern lowlands, is similarly ancient, yet apparently has few valley networks. This regional lack of valley networks only matches Noachian precipitation predictions from climate models if the Noachian climate was dry and cold [1]. In this scenario, highlands dissection was caused by transient flows of meltwater from large, regionally restricted ice-bodies. However, new results [2,3] show that Arabia Terra is not as poorly dissected as previously thought, and in fact there are extensive networks of inverted channel systems. Here, we describe an example of such a system - Aram Dorsum - which has been studied extensively as an ExoMars Rover candidate landing site. Aram Dorsum is an ~100 km long, 1-2 km wide, branching, flat-topped ridge system, in western Arabia Terra. We have mapped the system using CTX images, DEMs and other data. We interpret the ridge system to be fluvial in origin, preserved in positive relief due to infill and differential erosion; this working hypothesis is used as a conceptual framework for the study. Aram Dorsum is a branching, multi-level, contributory network, set in surrounding floodplains-like material. This demonstrates that it was a relatively long-lived, aggradational fluvial system, rather than an erosional outflow or bedrock-carved fluvial channel. Interestingly, the system shows little evidence for unconfined lateral channel migration, so there must have been significant bank stability. Aram Dorsum was therefore probably once a sizable river and, as just one example of many similar systems, is an exemplar for the middle part of a regional sediment transport system that could have extended from the southern highlands to the northern lowlands. Like Aram Dorsum, many of these other recently-recognized fluvial systems have an origin more consistent with

  7. Aram Chaos: a Long Lived Subsurface Aqueous Environment with Strong Water Resources Potential for Human Missions on Mars

    Science.gov (United States)

    Sibille, L.; Mueller, R.; Niles, P. B.; Glotch, T.; Archer, P. D.; Bell, M. S.

    2015-01-01

    Aram Chaos, Mars is a crater 280 kilometers in diameter with elevations circa. minus 2 to minus 3 kilometers below datum that provides a compelling landing site for future human explorers as it features multiple scientific regions of interest (ROI) paired with a rich extensible Resource ROI that features poly-hydrated sulfates [1]. The geologic history of Aram Chaos suggests several past episodes of groundwater recharge and infilling by liquid water, ice, and other materials [1-3]. The creation of the fractured region with no known terrestrial equivalent may have been caused by melting of deep ice reservoirs that triggered the collapse of terrain followed by catastrophic water outflows over the region. Aram Chaos is of particular scientific interest because it is hypothesized that the chaotic terrain may be the source of water that contributed to the creation of nearby valleys such as Ares Vallis flowing toward Chryse Planitia. The liquid water was likely sourced as groundwater and therefore represents water derived from a protected subsurface environment making it a compelling astrobiological site [2]. The past history of water is also represented by high concentrations of hematite, Fe-oxyhydroxides, mono-hydrated and poly-hydrated sulfates [1, 2]. Poly-hydrated sulfates are likely to contain abundant water that evolves at temperatures below 500 degrees Centigrade thus conferring Aram Chaos a potentially high value for early in-situ resource utilization (ISRU) [4]. The geologic history also calls for future prospecting of deep ice deposits and possibly liquid water via deep drilling. The most recent stratigraphic units in the central part of Aram Chaos are not fractured, and are part of a dome-shaped formation that features bright, poorly-consolidated material that contains both hydrated sulfates and ferric oxides according to OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) data [5]. These surface material characteristics are

  8. A supramolecular tubular nanoreactor.

    Science.gov (United States)

    Li, Zhi-Qiang; Zhang, Ying-Ming; Chen, Yong; Liu, Yu

    2014-07-01

    The extremely strong noncovalent complexation between the rigid host of phthalocyanine-bridged β-cyclodextrins and the amphiphilic guest carboxylated porphyrin is employed to construct a hollow tubular structure as a supramolecular nanoreactor. A representative coupling reaction occurs in the hydrophobic interlayers of the tubular walls in pure water at room temperature, leading to an enhancement of ten times higher reaction rate without any adverse effect on catalytic activity and conversion. PMID:24890802

  9. Tubular Secretion in CKD.

    Science.gov (United States)

    Suchy-Dicey, Astrid M; Laha, Thomas; Hoofnagle, Andrew; Newitt, Rick; Sirich, Tammy L; Meyer, Timothy W; Thummel, Ken E; Yanez, N David; Himmelfarb, Jonathan; Weiss, Noel S; Kestenbaum, Bryan R

    2016-07-01

    Renal function generally is assessed by measurement of GFR and urinary albumin excretion. Other intrinsic kidney functions, such as proximal tubular secretion, typically are not quantified. Tubular secretion of solutes is more efficient than glomerular filtration and a major mechanism for renal drug elimination, suggesting important clinical consequences of secretion dysfunction. Measuring tubular secretion as an independent marker of kidney function may provide insight into kidney disease etiology and improve prediction of adverse outcomes. We estimated secretion function by measuring secreted solute (hippurate, cinnamoylglycine, p-cresol sulfate, and indoxyl sulfate) clearance using liquid chromatography-tandem mass spectrometric assays of serum and timed urine samples in a prospective cohort study of 298 patients with kidney disease. We estimated GFR by mean clearance of creatinine and urea from the same samples and evaluated associations of renal secretion with participant characteristics, mortality, and CKD progression to dialysis. Tubular secretion rate modestly correlated with eGFR and associated with some participant characteristics, notably fractional excretion of electrolytes. Low clearance of hippurate or p-cresol sulfate associated with greater risk of death independent of eGFR (hazard ratio, 2.3; 95% confidence interval, 1.1 to 4.7; hazard ratio, 2.5; 95% confidence interval, 1.0 to 6.1, respectively). Hazards models also suggested an association between low cinnamoylglycine clearance and risk of dialysis, but statistical analyses did not exclude the null hypothesis. Therefore, estimates of proximal tubular secretion function correlate with glomerular filtration, but substantial variability in net secretion remains. The observed associations of net secretion with mortality and progression of CKD require confirmation. PMID:26614381

  10. Tubular toxicity of proteinuria.

    Science.gov (United States)

    Baines, Richard J; Brunskill, Nigel J

    2011-03-01

    Proteinuria is a prognostic indicator of progressive kidney disease and poor cardiovascular outcomes. Abnormally filtered bioactive macromolecules interact with proximal tubular epithelial cells (PTECs), which results in the development of proteinuric nephropathy. This condition is characterized by alterations in PTEC growth, apoptosis, gene transcription and inflammatory cytokine production as a consequence of dysregulated signaling pathways that are stimulated by proteinuric tubular fluid. The megalin-cubilin complex mediates the uptake of several proteins, including albumin, into PTECs. Megalin might also possess intrinsic signaling properties and the ability to regulate cell signaling pathways and gene transcription after processing regulated intramembrane proteolysis. Megalin could, therefore, link abnormal PTEC albumin exposure with altered growth factor receptor activation, proinflammatory and profibrotic signaling, and gene transcription. Evidence now suggests that other PTEC pathways for protein reabsorption of (patho)physiological importance might be mediated by the neonatal Fc receptor and CD36. PMID:21151210

  11. Análise inicial do uso de enxerto tubular orgânico L-D-Hydro - (Eato L-D-Hydro para realização de Blalock-Taussig modificado nas cardiopatias congênitas com hipofluxo pulmonar Initial analysis of the use of the L-D-Hydro (Eato L-D-Hydro organic tubular graft for performing the modified Blalock-Taussig procedure in congenital heart diseases with decreased pulmonary blood flow

    Directory of Open Access Journals (Sweden)

    Wilson Luiz da Silveira

    2005-03-01

    Full Text Available OBJETIVO: Analisar os resultados iniciais da utilização do enxerto tubular orgânico, utilizados para anastomoses sistêmico-pulmonares. MÉTODOS: De março/2002 a abril/2003, 10 pacientes foram submetidos à realização de shunt sistêmico pulmonar tipo Blalock-Taussig modificado utilizando um novo tipo de enxerto biológico originado da artéria mesentérica bovina tratada com poliglicol denominado L-D-Hydro. A idade variou de 3 dias a 7 anos e 60% dos pacientes eram do sexo masculino. O diagnóstico das cardiopatias foi determinado pela ecocardiografia, todos apresentando sinais clínicos de hipóxia severa (cianose. As cardiopatias foram: tetralogia de Fallot (40%, atresia tricúspide (50%, defeito do septo atrioventricular (10%. RESULTADOS: Em 10 pacientes, ocorreu um óbito por sepse e em nove houve melhora imediata na saturação de O2 ao oxímetro de pulso e da pressão parcial de oxigênio à gasometria arterial. Nenhum paciente apresentou obstrução do shunt no pós-operatório imediato ou qualquer outra complicação. Todos os pacientes mostraram shunt pérvio ao exame ecocardiográfico no pós-operatório imediato e tardio, realizado no 3º mês de pós-operatório. Nenhum paciente apresentou sangramento no intra e pós-operatório. CONCLUSÃO: O enxerto tubular L-D-HYDRO demonstrou ser promissor para a realização de shunt sistêmico pulmonar, como alternativa para produtos inorgânicos existentes no mercado, entretanto, temos de ter maior número de implantes e acompanhamento tardio para uma avaliação definitiva.OBJECTIVE: To analyze the initial results of the use of an organic tubular graft for systemic-pulmonary anastomoses. METHODS: From March 2002 to April 2003, 10 patients underwent systemic-pulmonary shunt of the modified Blalock-Taussig type, using a new type of biological graft originating from the bovine mesenteric artery treated with polyglycol, the so-called L-D-Hydro. The patients' ages ranged from 3 days to 7

  12. Sistema de Gestión de Remontes y Control de Accesos en la Estación de Esquí Aramón Cerler. Estudio de Implatación de Nuevos Productos

    OpenAIRE

    Mora Fillat, Cruz

    2004-01-01

    La Estación Invernal de Aramón Cerler se encuentra en el Pirineo aragonés, en el corazón del Valle de Benasque y pertenece al grupo Aramón, único holding español de la nieve que agrupa las estaciones de esquí de Cerler, Formigal, Panticosa, Javalambre y Valdelinares y representa el 20% de la superficie esquiable del mercado nacional. El objetivo actual de Aramón Cerler es establecer un Sistema de Información que permita capturar, procesar, almacenar, y distribuir toda la infor...

  13. Classifying Virtually Special Tubular Groups

    OpenAIRE

    Woodhouse, Daniel J.

    2016-01-01

    A group is tubular if it acts on a tree with $\\mathbb{Z}^2$ vertex stabilizers and $\\mathbb{Z}$ edge stabilizers. We prove that a tubular group is virtually special if and only if it acts freely on a locally finite CAT(0) cube complex. Furthermore, we prove that if a tubular group acts freely on a finite dimensional CAT(0) cube complex, then it virtually acts freely on a three dimensional CAT(0) cube complex.

  14. General Construction of Tubular Geometry

    CERN Document Server

    Mukhopadhyay, Partha

    2016-01-01

    We consider the problem of locally describing tubular geometry around a submanifold embedded in a (pseudo)Riemannian manifold in its general form. Given the geometry of ambient space in an arbitrary coordinate system and equations determining the submanifold in the same system, we compute the tubular expansion coefficients in terms of this {\\it a priori data}. This is done by using an indirect method that crucially applies the tubular expansion theorem for vielbein previously derived. With an explicit construction involving the relevant coordinate and non-coordinate frames we verify consistency of the whole method up to quadratic order in vielbein expansion. Furthermore, we perform certain (long and tedious) higher order computation which verifies the first non-trivial spin connection term in the expansion for the first time. Earlier a similar method was used to compute tubular geometry in loop space. We explain this work in the light of our general construction.

  15. Sistema automático para determinação seqüencial de cianeto livre e total empregando eletrodo tubular íon-seletivo de membrana homogênea

    Directory of Open Access Journals (Sweden)

    Marin Maria Angélica Bonadiman

    2000-01-01

    Full Text Available This study presents an automated system for potentiometric determination of free and total cyanide which employs a homogeneous membrane tubular ion-selective electrode. After the electrode is assembled, it is connected to a system composed of 3 three-way solenoid valves, sample line, carrier line, acid stream, and gas diffusion chamber. A Turbo Pascal® computer program, developed specifically for this task, automatically performs all the steps involved in data acquisition and processing. The proposed analytical procedure offers operational simplicity, since detection is performed by a tubular electrode, whose assembly is fast and easy. The system has shown reproducibility (r.s.d. < 0.5%, n=6 and high speed (30 readings/hour; it is efficient for determination of free and total cyanide in waste waters of starch processing plants. The detection limit was 1.2x10-5 and 1.5x10-5 mol L-1, for determination of free and total cyanide, respectively. The linear response range was between 1.2x10-5 and 1.0x10-2 mol L-1 for free cyanide and between 1.5x10-5 and 1.0x10-2 for total cyanide.

  16. Tubular cystourethroneostomy after total prostatectomy.

    Science.gov (United States)

    Melchior, H

    1975-01-01

    After radical prostatectomy cystourethroneostomy is done as a tubular cystourethroplasty. In the last 13 months 14 patients have been operated on in this manner. In 12 patients continence was achieved; 2 patients had a temporary stress incontinence. The stress incontinence could be treated successfully by temporary electrostimulation of the pelvic floor by an anal plug stimulator.

  17. Excitons in tubular molecular aggregates

    NARCIS (Netherlands)

    Didraga, C; Knoester, J

    2004-01-01

    We present a brief overview of recent work on the optical properties of molecular aggregates with a tubular (cylindrical) shape. The exciton states responsible for these properties can be distinguished with regard to a transverse wave number, which directly relates to optical selection rules and pol

  18. Renal tubular acidosis type 4 in pregnancy.

    Science.gov (United States)

    Jakes, Adam Daniel; Baynes, Kevin; Nelson-Piercy, Catherine

    2016-03-17

    We describe the clinical course of renal tubular acidosis (RTA) type 4 in pregnancy, which has not been previously published. Renal tubular acidosis type 4 is a condition associated with increased urinary ammonia secondary to hypoaldosteronism or pseudohypoaldosteronism. Pregnancy may worsen the hyperkalaemia and acidosis of renal tubular acidosis type 4, possibly through an antialdosterone effect. We advise regular monitoring of potassium and pH throughout pregnancy to ensure safe levels are maintained.

  19. Modified tubularized incised plate urethroplasty

    Directory of Open Access Journals (Sweden)

    Shivaji Mane

    2013-01-01

    Full Text Available Aim: To share our experience of doing tubularized incised plate urethroplasty with modifications. Materials and Methods: This is a single surgeon personal series from 2004 to 2009. One hundred patients of distal hypospadias were subjected for Snodgrass urethroplasty with preputioplasty. The age range was 1 to 5 year with mean age of 2.7 years. Selection criteria were good urethral plate, without chordee and torsion needing complete degloving. Main technical modification from original Snodgrass procedure was spongioplasty, preputioplasty, and dorsal slit when inability to retract prepuce during surgery. Results: Average follow-up period is 23 months. Seven (7% patients developed fistula and one patient had complete preputial dehiscence. Phimosis developed in three (3% patients and required circumcision. Dorsal slit was required in seven patients. One patient developed meatal stenosis in postoperative period. All other patients are passing single urinary stream and have cosmesis that is acceptable. Conclusions: Modified tubularized incised plate urethroplasty with preputioplasty effectively gives cosmetically normal looking penis with low complications.

  20. The rebirth of interest in renal tubular function.

    Science.gov (United States)

    Lowenstein, Jerome; Grantham, Jared J

    2016-06-01

    The measurement of glomerular filtration rate by the clearance of inulin or creatinine has evolved over the past 50 years into an estimated value based solely on plasma creatinine concentration. We have examined some of the misconceptions and misunderstandings of the classification of renal disease and its course, which have followed this evolution. Furthermore, renal plasma flow and tubular function, which in the past were estimated by the clearance of the exogenous aryl amine, para-aminohippurate, are no longer measured. Over the past decade, studies in experimental animals with reduced nephron mass and in patients with reduced renal function have identified small gut-derived, protein-bound uremic retention solutes ("uremic toxins") that are poorly filtered but are secreted into the lumen by organic anion transporters (OATs) in the proximal renal tubule. These are not effectively removed by conventional hemodialysis or peritoneal dialysis. Residual renal function, urine produced in patients with advanced renal failure or undergoing dialysis treatment, may represent, at least in part, secretion of fluid and uremic toxins, such as indoxyl sulfate, mediated by proximal tubule OATs and might serve as a useful survival function. In light of this new evidence of the physiological role of proximal tubule OATs, we suggest that measurement of renal tubular function and renal plasma flow may be of considerable value in understanding and managing chronic kidney disease. Data obtained in normal subjects indicate that renal plasma flow and renal tubular function might be measured by the clearance of the endogenous aryl amine, hippurate.

  1. The rebirth of interest in renal tubular function.

    Science.gov (United States)

    Lowenstein, Jerome; Grantham, Jared J

    2016-06-01

    The measurement of glomerular filtration rate by the clearance of inulin or creatinine has evolved over the past 50 years into an estimated value based solely on plasma creatinine concentration. We have examined some of the misconceptions and misunderstandings of the classification of renal disease and its course, which have followed this evolution. Furthermore, renal plasma flow and tubular function, which in the past were estimated by the clearance of the exogenous aryl amine, para-aminohippurate, are no longer measured. Over the past decade, studies in experimental animals with reduced nephron mass and in patients with reduced renal function have identified small gut-derived, protein-bound uremic retention solutes ("uremic toxins") that are poorly filtered but are secreted into the lumen by organic anion transporters (OATs) in the proximal renal tubule. These are not effectively removed by conventional hemodialysis or peritoneal dialysis. Residual renal function, urine produced in patients with advanced renal failure or undergoing dialysis treatment, may represent, at least in part, secretion of fluid and uremic toxins, such as indoxyl sulfate, mediated by proximal tubule OATs and might serve as a useful survival function. In light of this new evidence of the physiological role of proximal tubule OATs, we suggest that measurement of renal tubular function and renal plasma flow may be of considerable value in understanding and managing chronic kidney disease. Data obtained in normal subjects indicate that renal plasma flow and renal tubular function might be measured by the clearance of the endogenous aryl amine, hippurate. PMID:26936872

  2. Tubular stabilizer bars – calculations and construction

    Directory of Open Access Journals (Sweden)

    Adam-Markus WITTEK

    2011-01-01

    Full Text Available The article outlines the calculation methods for tubular stabilizer bars. Modern technological and structural solutions in contemporary cars are reflected also in the construction, selection and manufacturing of tubular stabilizer bars. A proper construction and the selection of parameters influence the strength properties, the weight, durability and reliability as well as the selection of an appropriate production method.

  3. Tubular lining material for pipelines having bends

    Energy Technology Data Exchange (ETDEWEB)

    Moringa, A.; Sakaguchi, Y.; Hyodo, M.; Yagi, I.

    1987-03-24

    A tubular lining material for pipelines having bends or curved portions comprises a tubular textile jacket made of warps and wefts woven in a tubular form overlaid with a coating of a flexible synthetic resin. It is applicable onto the inner surface of a pipeline having bends or curved portions in such manner that the tubular lining material with a binder onto the inner surface thereof is inserted into the pipeline and allowed to advance within the pipeline, with or without the aid of a leading rope-like elongated element, while turning the tubular lining material inside out under fluid pressure. In this manner the tubular lining material is applied onto the inner surface of the pipeline with the binder being interposed between the pipeline and the tubular lining material. The lining material is characterized in that a part of all of the warps are comprised of an elastic yarn around which, over the full length thereof, a synthetic fiber yarn or yarns have been left-and/or right-handedly coiled. This tubular lining material is particularly suitable for lining a pipeline having an inner diameter of 25-200 mm and a plurality of bends, such as gas service pipelines or house pipelines, without occurrence of wrinkles in the lining material in a bend.

  4. Estudio de la distribución de los tiempos de residencia en un reactor tubular para la hidrólisis de lecitina de soja con fosfolipasa A2 inmovilizada

    Directory of Open Access Journals (Sweden)

    Zaritzky, N.

    2001-10-01

    efectuada mediante el uso de enzima fosfolipasa A2 inmovilizada, liberando un ácido graso de la posición C-2 de los fosfolípidos para obtener un producto enriquecido en lisolecitinas. La reacción enzimática sigue una cinética de primer orden cuando las concentraciones de sustrato están dentro del rango: 6,34 10-3 y 19,0 10-3M. El valor de la constante de velocidad es: k= 9,88 10-2 min-1 cuando la enzima está inmovilizada sobre alúmina. Se construyó un reactor que permite la circulación del fluido a través del soporte. El soporte seleccionado fue alúmina en consideración a sus buenas propiedades mecánicas y a su bajo costo. Fue analizado el comportamiento del flujo en el reactor, y cuanto este se aparta del modelo ideal de flujo en pistón, inyectando una solución de 1 % NaCl (trazador en forma de inyección por impulso. La medición de la conductividad de la solución efluente resultó adecuada para la determinación de los tiempos de residencia. El sistema mostró comportamiento lineal. Se analizaron los tiempos de residencia en el reactor utilizando tres diferentes volúmenes de flujo para diferentes arreglos de soporte y material inerte. Se calcularon las fracciones no convertidas en el reactor y se observaron las diferencias a la salida en comparación a las de un reactor de flujo en pistón, precisamente porque se generan canalizaciones y cortocircuitos en la columna. La conversión máxima resultó para las más altas concentraciones de sustrato y para el menor flujo de alimentación. El módulo de dispersión resultó bastante mayor que el límite que introduce una curva gaussiana para el caso en el cual el grado de suposición de alta dispersión fue corregido. El reactor alcanzó un comportamiento similar al de un reactor de mezcla completa y se concluyó que son importantes el grado de retromezcla, la formación de remolinos y zonas de redistribución de material.

  5. Tubular inverse opal scaffolds for biomimetic vessels

    Science.gov (United States)

    Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

    2016-07-01

    There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

  6. Tubular bioreactor and its application; Tubular bioreactor to sono tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Endo, I.; Nagamune, T. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Yuki, K. [Nikka Whisky Distilling Co. Ltd. Tokyo (Japan); Inaba, H. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1994-09-05

    The loop type tubular bioreactor (TBR) was developed where biocatalysts are trapped in the reactor by membrane module. A UF membrane or MF membrane and crossflow filtration were adopted for the membrane module, and the reactor loop was composed of four membrane modules. The reactor was operated at 2-4 m/s in membrane surface velocity and 300-400 kPa in filtration pressure. As the result of the high-density culture of lactic acid bacteria and yeast, a biomass concentration was more than 10 times that in batch culture, suggesting the remarkable enhancement of a production efficiency. As the result of the continuous fermentation of cider, the fast fermentation more than 60 times that in conventional ones was obtained together with the same quality as conventional ones. Such a fast fermentation was probably achieved by yeast suspended in the fermenter of TBR, by yeast hardly affected physico-chemically as compared with immobilized reactors, and by small effect of mass transfer on reaction systems. 4 refs., 6 figs.

  7. Iatrogenic Digital Compromise with Tubular Dressings

    Directory of Open Access Journals (Sweden)

    Corre, Kenneth A

    2009-08-01

    Full Text Available Objective: This case report describes a digit amputation resulting from an improperly applied tubular dressing. The safe application of digital tubular dressings, and the rationale behind it, is detailed to raise emergency physician (EP awareness.Methods: We present a case report of a recent iatrogenic-induced digit ischemia caused by improperly applied tube gauze. We review the literature on the subject and the likely sources of poor outcomes presented. The proper application of tubular gauze dressings is then outlined.Conclusion: EPs and emergency department personnel must be educated on the safe application of tubular gauze dressings to avoid dire outcomes associated with improper applications.[WestJEM. 2009;10:190-192.

  8. Thermal CFD Analysis of Tubular Light Guides

    OpenAIRE

    Ondřej Šikula; Jitka Mohelníková; Josef Plášek

    2013-01-01

    Tubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulen...

  9. 78 FR 37584 - U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United...

    Science.gov (United States)

    2013-06-21

    ... Employment and Training Administration U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United States Steel Corporation, Mckeesport, Pennsylvania; Notice of Amended... workers of U.S. Steel Tubular Products, McKeesport Tubular Operations Division, a subsidiary of...

  10. Thermal CFD Analysis of Tubular Light Guides

    Directory of Open Access Journals (Sweden)

    Ondřej Šikula

    2013-12-01

    Full Text Available Tubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.

  11. Validação das definições de termos identificados no projeto CIPESC para o eixo foco da prática de enfermagem da CIPE®

    Directory of Open Access Journals (Sweden)

    Telma Ribeiro Garcia

    2002-02-01

    Full Text Available Em continuidade à contribuição da Enfermagem brasileira para a elaboração da CIPEâ, que está sendo construída sob a coordenação do CIE, objetivou-se neste trabalho definir os termos identificados no projeto CIPESC e classificados no eixo foco da prática de enfermagem da Classificação de Fenômenos de Enfermagem da CIPE® - versão Beta e validar essas definições junto a um grupo de juízes composto por profissionais com envolvimento anterior na execução do projeto CIPESC, ou com envolvimento docente ou assistencial na área de Enfermagem em Saúde Coletiva. O processo foi realizado em duas fases, considerando-se validadas as definições que alcançaram um índice de Concordância (IC³ 0,80 entre o grupo de juízes. Noventa e nove definições de termos foram validadas: 26 alcançaram IC igual a 1,00; 56 alcançaram IC entre 0,90 e 0,99 e 17 alcançaram IC entre 0,80 e 0,89. A definição de um termo não foi validada.

  12. Tubular membrane bioreactors for biotechnological processes.

    Science.gov (United States)

    Wolff, Christoph; Beutel, Sascha; Scheper, Thomas

    2013-02-01

    This article is an overview of bioreactors using tubular membranes such as hollow fibers or ceramic capillaries for cultivation processes. This diverse group of bioreactor is described here in regard to the membrane materials used, operational modes, and configurations. The typical advantages of this kind of system such as environments with low shear stress together with high cell densities and also disadvantages like poor oxygen supply are summed up. As the usage of tubular membrane bioreactors is not restricted to a certain organism, a brief overview of various applications covering nearly all types of cells from prokaryotic to eukaryotic cells is also given here. PMID:23224587

  13. Tubular solid oxide fuel cell current collector

    Science.gov (United States)

    Bischoff, Brian L.; Sutton, Theodore G.; Armstrong, Timothy R.

    2010-07-20

    An internal current collector for use inside a tubular solid oxide fuel cell (TSOFC) electrode comprises a tubular coil spring disposed concentrically within a TSOFC electrode and in firm uniform tangential electrical contact with the electrode inner surface. The current collector maximizes the contact area between the current collector and the electrode. The current collector is made of a metal that is electrically conductive and able to survive under the operational conditions of the fuel cell, i.e., the cathode in air, and the anode in fuel such as hydrogen, CO, CO.sub.2, H.sub.2O or H.sub.2S.

  14. Drill pipes and casings utilizing multi-conduit tubulars

    Energy Technology Data Exchange (ETDEWEB)

    Curlett, H.B.

    1989-01-24

    A seal adapted for use with a multi-conduit well tubular, or the like, is described which consists of: a plate with fluid passages, each passage corresponding to an opening of a conduit of the multiconduit tubular, and a groove on the plate around each passage; and elastomer means partially embeddable into each groove for sealing each conduit of a tubular to a corresponding conduit of another similar tubular.

  15. Work tool in a tubular element

    International Nuclear Information System (INIS)

    The stand, which is positioned in relation with the tubular element, has clutch disengagement means for a working rod in rotation, with at least two positioning regions on the rod. Application for laser welding a sleeve into PWR steam generator tubes

  16. Tubular Membrane Plant-Growth Unit

    Science.gov (United States)

    Dreschel, Thomas W.

    1992-01-01

    Hydroponic system controls nutrient solution for growing crops in space. Pump draws nutrient solution along inside of tubular membrane in pipe from reservoir, maintaining negative pressure in pipe. Roots of plants in slot extract nutrient through membrane within pipe. Crop plants such as wheat, rice, lettuce, tomatoes, soybeans, and beans grown successfully with system.

  17. Reliability Analysis of Tubular Joints in Offshore Structures

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Sørensen, John Dalsgaard

    1987-01-01

    Reliability analysis of single tubular joints and offshore platforms with tubular joints is" presented. The failure modes considered are yielding, punching, buckling and fatigue failure. Element reliability as well as systems reliability approaches are used and illustrated by several examples....... Finally, optimal design of tubular.joints with reliability constraints is discussed and illustrated by an example....

  18. Vibration analysis of ultrasonic tubular resonators

    Institute of Scientific and Technical Information of China (English)

    LIANG Zhaofeng; MO Xiping; ZHOU Guangping

    2012-01-01

    The frequency equation of the axisymmetric coupled vibration of a ultrasonic tubular resonator with both ends free is derived by an exact solution method, based on classical Fliigge thin shell theory. The dependence of the dimensionless frequency Ω on the ratio of length to radius 1/a, the ratio of radius to thickness a/h and Poisson's ratio v is investigated, and the axisymmetric coupled vibration of the ultrasonic tubular resonator with both ends shear diaphragm is compared with that with both ends free. The accuracy of two-dimensional and three-dimensional apparent elasticity method is also assessed by the comparison with the exact solution method. Finally, the mode shapes of the ultrasonic tubular resonator are calculated by the exact solution method, and its transform efficient is analyzed. The results show that as for two boundary conditions of both ends free and both ends shear diaphragm, the difference of the effect of the boundary conditions on the dimensionless frequency of the axisymmetric coupled vibration of the ultrasonic tubular resonator becomes smaller as l/a increases, and the larger a/h, the smaller the difference. Moreover, for free-free boundary conditions, the change of a/h has nearly no effect on the dimensionless frequency of the thin tubular resonator usually considered to mean a/h 〉 10. Purthermore, the dimensionless frequency Ω decreases as v in- creases for a given l/a, and the impact of v on Ω is different for different l/a, and the maximum impact will appear when l/a = π. Finally, the study also shows the three-dimensional apparent elasticity method has very high accuracy.

  19. 78 FR 14361 - U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United...

    Science.gov (United States)

    2013-03-05

    ... Employment and Training Administration U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United States Steel Corporation, Mckeesport, PA; Notice of Initiation of...) filed on December 20, 2012 on behalf of workers of U.S. Steel Tubular Products, McKeesport...

  20. Customização da ferramenta Taram para projetos florestais de MDL com Pinus Taeda L. no extremo sul do Paraná.

    OpenAIRE

    Fernandes, Lucila de Almeida Vasques

    2013-01-01

    O objetivo deste estudo foi customizar a ferramenta TARAM, por meio da aplicação da metodologia aprovada do Mecanismo de Desenvolvimento Limpo (MDL) AR-AM0005, para projetos florestais de MDL com Pinus taeda L. na região extremo sul do Paraná. Para tanto, foi simulada a produção volumétrica (m³.ha-1) de diversos regimes de manejo com idades de corte raso de 20 e 30 anos. O valor presente líquido (VPL) por hectare de cada regime de manejo foi calculado, para seleção de dois regimes de manejo: ...

  1. Apparatus for servicing tubular strings in subterranean wells

    Energy Technology Data Exchange (ETDEWEB)

    Kahil, J.E.; Jaynes, M.S.; Harrell, K.R.

    1987-12-29

    This patent describes an apparatus for use in servicing a tubular string formed from a series of interconnected tubular sections used in subterranean oil or gas wells. The apparatus includes a substantially horizontal floor and a structure positionable over the well head for sequentially hoisting and lowering individual tubular sections of the tubular string through the floor relative to the well head. The improvement comprises: an annular defect detecting housing fixedly positioned on the well head below the floor in surrounding relation to the path of the sequentially removed tubular sections; insulating segments rotationally fixed with respect to the housing and mounted in the annular housing for radial movement between an inner detecting position and an outer position for clearing obstructions carried by the tubular sections; means for limiting radially inward movement of the insulating segments to the inner detecting position spaced outwardly from engagement with the tubular sections; means for detecting an approaching obstruction on any tubular section for concurrently shifting the insulating segments to the outer position; detecting means mounted on the insulating segments in surrounding relation to the path travelled by the sequentially removed tubular sections; and the detecting means comprising means for determining the existence of different defects in each tubular section as each tubular section is passed through the annular defect detecting housing.

  2. Tubular Heart Pumping Mechanisms in Ciona Intestinalis

    Science.gov (United States)

    Battista, Nicholas; Miller, Laura

    2015-11-01

    In vertebrate embryogenesis, the first organ to form is the heart, beginning as a primitive heart tube. However, many invertebrates have tubular hearts from infancy through adulthood. Heart tubes have been described as peristaltic and impedance pumps. Impedance pumping assumes a single actuation point of contraction, while traditional peristalsis assumes a traveling wave of actuation. In addition to differences in flow, this inherently implies differences in the conduction system. It is possible to transition from pumping mechanism to the other with a change in the diffusivity of the action potential. In this work we consider the coupling between the fluid dynamics and electrophysiology of both mechanisms, within a basal chordate, the tunicate. Using CFD with a neuro-mechanical model of tubular pumping, we discuss implications of the both mechanisms. Furthermore, we discuss the implications of the pumping mechanism on evolution and development.

  3. Glomerular tubular balance: mediation by luminal hypotonicity.

    Science.gov (United States)

    Häberle, D A; Müller, U; Nagel, W

    1989-01-01

    Late proximal rat tubular segments were microperfused with slightly hypo- or hypertonic artificial late proximal tubular fluid (ATF) at low (11-13 nl/min) or high (30-38 nl/min) perfusion rates. Volume reabsorption, net chloride and solute reabsorption were measured as a function of length. In addition, the transepithelial resistance and voltage (Vte) were measured as a function of the applied osmotic gradient. Hypertonic solutions equilibrated to isotonicity by solute outflow rather than water influx. With hypertonic ATF the lumen positive Vte was decreased compared with free flow or with hypotonic ATF. The resistance was not significantly different between the different groups. In contrast to hypotonic ATF, hypertonic or isotonic ATF was not significantly reabsorbed. In addition, hypotonic ATF maintained its hypotonicity along the perfused segments. Its reabsorption was flow-dependent. Hypotonicity appeared to enhance solute reabsorption. PMID:2725432

  4. Pointlike Inclusion Interactions in Tubular Membranes

    Science.gov (United States)

    Vahid, Afshin; Idema, Timon

    2016-09-01

    Membrane tubes and tubular networks are ubiquitous in living cells. Inclusions like proteins are vital for both the stability and the dynamics of such networks. These inclusions interact via the curvature deformations they impose on the membrane. We analytically study the resulting membrane mediated interactions in strongly curved tubular membranes. We model inclusions as constraints coupled to the curvature tensor of the membrane tube. First, as special test cases, we analyze the interaction between ring- and rod-shaped inclusions. Using Monte Carlo simulations, we further show how pointlike inclusions interact to form linear aggregates. To minimize the curvature energy of the membrane, inclusions self-assemble into either line- or ringlike patterns. Our results show that the global curvature of the membrane strongly affects the interactions between proteins embedded in it, and can lead to the spontaneous formation of biologically relevant structures.

  5. Tubular electric heater with a thermocouple assembly

    International Nuclear Information System (INIS)

    This patent relates to a thermocouple or other instrumentation which is installed within the walls of a tubular sheath surrounding a process device such as an electric heater. The sheath comprises two concentric tubes, one or both of which have a longitudinal, concave crease facing the other tube. The thermocouple is fixedly positioned within the crease and the outer tube is mechanically reduced to form an interference fit onto the inner tube

  6. Inherited renal tubular defects with hypokalemia

    OpenAIRE

    Muthukrishnan J; Modi K; Kumar P; Jha Ratan

    2009-01-01

    Bartter′s and Gitelman′s syndrome are two ends of a spectrum of inherited renal tubular disorders that present with hypokalemic metabolic alkalosis of varying severity. Clinical features and associated calcium and magnesium ion abnormalities are used to diagnose these cases after excluding other commoner causes. We report on two cases, the first being a young boy, born of pregnancy complicated by polyhydramnios, who had classical dysmorphic features, polyuria, hypokalemia and hy...

  7. Energy production with a tubular propeller turbine

    OpenAIRE

    Almeida Samora, Irene; Hasmatuchi, Vlad; Münch-Alligné, C.; Franca, Mário J.; Schleiss, Anton; Helena M. Ramos

    2016-01-01

    Micro-hydropower is a way of improving the energetic efficiency of existent water systems. In the particular case of drinking water systems, several studies have showed that pressure reducing valves can be by-passed with turbines in order to recover the dissipated hydraulic energy to produce electricity. As conventional turbines are not always cost-effective for power under 20 kW, a new energy converter is studied. A five blade tubular propeller (5BTP), assessed through laboratorial tests on ...

  8. Distal renal tubular acidosis in recurrent renal stone formers

    DEFF Research Database (Denmark)

    Osther, P J; Hansen, A B; Røhl, H F

    1989-01-01

    Renal acidification ability was examined in 90 recurrent renal stone formers, using fasting morning urinary pH levels followed by a short ammonium chloride loading test in subjects with pH levels above 6.0. Fifteen patients (16.6%) revealed a distal renal tubular acidification defect: one patient...... (1.1%) had complete distal renal tubular acidosis and 14 (15.5%) incomplete distal renal tubular acidosis. Our results confirm that distal renal tubular acidification defects are associated with a more severe form of stone disease and make distal renal tubular acidosis one of the most frequent...... metabolic disturbances in renal stone formers. Distal renal tubular acidosis (dRTA) was relatively more common in female stone formers and most often found in patients with bilateral stone disease (36%). Since prophylactic treatment in renal stone formers with renal acidification defects is available...

  9. A simple auxetic tubular structure with tuneable mechanical properties

    Science.gov (United States)

    Ren, Xin; Shen, Jianhu; Ghaedizadeh, Arash; Tian, Hongqi; Xie, Yi Min

    2016-06-01

    Auxetic materials and structures are increasingly used in various fields because of their unusual properties. Auxetic tubular structures have been fabricated and studied due to their potential to be adopted as oesophageal stents where only tensile auxetic performance is required. However, studies on compressive mechanical properties of auxetic tubular structures are limited in the current literature. In this paper, we developed a simple tubular structure which exhibits auxetic behaviour in both compression and tension. This was achieved by extending a design concept recently proposed by the authors for generating 3D metallic auxetic metamaterials. Both compressive and tensile mechanical properties of the auxetic tubular structure were investigated. It was found that the methodology for generating 3D auxetic metamaterials could be effectively used to create auxetic tubular structures as well. By properly adjusting certain parameters, the mechanical properties of the designed auxetic tubular structure could be easily tuned.

  10. Hyaluronan in Tubular and Interstitial Nephrocalcinosis

    Science.gov (United States)

    Verkoelen, Carl F.

    2007-04-01

    Hyaluronan (HA) is the major glycosaminoglycan (GAG) component of the renal medullary interstitium. HA is extremely large (up to 104 kDa) and composed of thousands repeating disaccharides of glucuronic acid (GlcUA) and N-acetylglucosamine (GlcNAc). HA is synthesized by hyaluronan synthases (HASs) and degraded by hyaluronidases (Hyals). The production of HA by renomedullary interstitial cells is mediated by local osmolality. When excess water needs to be excreted, increased interstitial HA seems to antagonize water reabsorption, while the opposite occurs during water conservation. Hence, papillary interstitial HA is low and Hyal high during anti-diuresis, whereas during diuresis HA is high and Hyal low. The polyanion HA plays a role in the reabsorption of hypotonic fluid by immobilizing cations (Na+) via the carboxylate (COO-) groups of GlcUA. The binding of Ca2+ to anionic HA is probably also responsible for the fact that the papilla does not become a stone despite the extremely high interstitial phosphate and oxalate. HA is also an excellent crystal binding molecule. The expression of HA at the luminal surface of renal tubular cells leads to tubular nephrocalcinosis (tubular NC). Calcium staining methods (Von Kossa, Yasue) demonstrated that crystallization inhibitors cannot avoid the occasional precipitation of calcium phosphate in the papillary interstitium (interstitial NC). These crystals are probably immediately immobilized by the gel-like HA matrix. After ulcerating through the pelvic wall the calcified matrix becomes a Randall's plaque. The attachment of calcium oxalate crystals from the primary urine to plaque may ultimately lead to the development of clinical stones in the renal calyces (nephrolithiasis).

  11. Discovery during Hydrogen Annealing: Formation of Nanoscale Fluorocarbon Tubular Structures

    Science.gov (United States)

    Hao, Xiuchun; Tanaka, Sinya; Masuda, Atsuhiko; Maenaka, Kazusuke; Higuchi, Kohei

    2013-09-01

    A novel fabrication method for nanoscale tubular structures is presented in this paper. The tubular structures can be obtained by heating single-crystal silicon trenches or pillars formed by the inductively coupled plasma reactive-ion etching (ICP-RIE) Bosch process in hydrogen ambient. The importance of initial vacuum in the reaction chamber for tube formation and the tube formation mechanism were discussed. The components and sidewall size of the tubular structure were also studied to verify that the tube is made of the fluorocarbon (CF) passivation layer deposited by the Bosch process. The CF tubular structure would be a promising structure for BioMEMS.

  12. Tubular solid oxide fuel cell development program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    This paper presents an overview of the Westinghouse Solid Oxide Fuel Cell (SOFC) development activities and current program status. The Westinghouse goal is to develop a cost effective cell that can operate for 50,000 to 100,000 hours. Progress toward this goal will be discussed and test results presented for multiple single cell tests which have now successfully exceeded 56,000 hours of continuous power operation at temperature. Results of development efforts to reduce cost and increase power output of tubular SOFCs are described.

  13. Forming of Polymeric Tubular Micro-components

    DEFF Research Database (Denmark)

    Qin, Yi; Zhao, Jie; Anyasodor, Gerald;

    2015-01-01

    platform for the production of functional polymeric tubular micro-components. The chapter gives background on the current market and process development trends, followed by description of materials, process configuration, tool design and machine development for each processing technology as well......This chapter is intended to provide an overview of three nontraditional shaping technologies for the forming of polymeric micro-tubes, which are hot embossing, blow molding, and cross rolling, as well as realization of a process chain and the integration of a modular machine-based manufacturing...

  14. Distal Renal Tubular Acidosis and Calcium Nephrolithiasis

    Science.gov (United States)

    Moe, Orson W.; Fuster, Daniel G.; Xie, Xiao-Song

    2008-09-01

    Calcium stones are commonly encountered in patients with congenital distal renal tubular acidosis, a disease of renal acidification caused by mutations in either the vacuolar H+-ATPase (B1 or a4 subunit), anion exchanger-1, or carbonic anhydrase II. Based on the existing database, we present two hypotheses. First, heterozygotes with mutations in B1 subunit of H+-ATPase are not normal but may harbor biochemical abnormalities such as renal acidification defects, hypercalciuria, and hypocitraturia which can predispose them to kidney stone formation. Second, we propose at least two mechanisms by which mutant B1 subunit can impair H+-ATPase: defective pump assembly and defective pump activity.

  15. Carbon Tubular Morphologies in Blast Furnace Coke

    OpenAIRE

    Stanislav S. Gornostayev; Jouko J. Härkki

    2008-01-01

    The paper reports on the first occurrence of microscale carbon tubular morphologies (CMTs) in a blast furnace (BF) coke. The CMTs were probably formed as a result of the conversion of solid disordered carbon via liquid phase metal particles involving a gas phase containing a substantial amount of N 2 and O 2 . The presence of CMTs may lie behind the generation of the smallest fraction of fines in BF exhaust dust. If the amount of CMTs present in the BF exhausts gases at any particular metallu...

  16. Carbon Tubular Morphologies in Blast Furnace Coke

    Directory of Open Access Journals (Sweden)

    Stanislav S. Gornostayev

    2008-01-01

    Full Text Available The paper reports on the first occurrence of microscale carbon tubular morphologies (CMTs in a blast furnace (BF coke. The CMTs were probably formed as a result of the conversion of solid disordered carbon via liquid phase metal particles involving a gas phase containing a substantial amount of N2 and O2. The presence of CMTs may lie behind the generation of the smallest fraction of fines in BF exhaust dust. If the amount of CMTs present in the BF exhausts gases at any particular metallurgical site proves to be substantial, it could become a subject of environmental concern.

  17. TUBULAR PHOTOBIOREACTOR FOR MICROALGAE BIODIESEL PRODUCTION

    OpenAIRE

    Nkongolo Mulumba; Ihab H. Farag

    2012-01-01

    Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year). However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR) was designed and achieved a ten times increase in algae concentration. It produced 1g of d...

  18. Strength of Concrete Filled Steel Tubular Columns

    Institute of Scientific and Technical Information of China (English)

    Muhammad Naseem Baig; FAN Jiansheng; NIE Jianguo

    2006-01-01

    Composite columns of steel and concrete have been used and studied world wide, but filled tubular columns need more attention. This paper presents an experimental study on the behavior of short concrete filled steel tubular columns (CFT) axially loaded in compression to failure. A total of 28 specimens (16 were filled with concrete and 12 were kept hollow) with different cross-sections were tested to investigate the load capacity. The length-to-diameter ratios of these columns were between 4 and 9. Parameters for the tests were tube shape and diameter-to-thickness ratio. Some of the concrete filled columns had internal bracing of #3 deformed bars. The test results are compared with the theoretical results and previous studies. The results show that the confinement effect on concrete does play a role in increasing the compressive strengths to almost 60% in some cases. Based on the test results, an equation to estimate the ultimate axial compressive loading capacities is also proposed for square CFT columns.

  19. Inspección Interactiva de Estructuras Anatómicas Tubulares

    OpenAIRE

    Díaz Iriberri, José

    2007-01-01

    El objetivo que se persigue con esta tesis es analizar y evaluar los diferentes sistemas de visualización de datos volumétricos utilizados para realizar inspecciones virtuales de estructuras tubulares, así como proponer algunas soluciones a las limitaciones de estos métodos. En el capítulo 2 se presentan las etapas principales en la visualización de datos de volumen: los sistemas de captación, el modelo de voxels, la segmentación o clasificación de los datos y las técnicas d...

  20. Nitrificación en reactores biopelícula de membrana tubular permeable a gases

    OpenAIRE

    Molina, Judith; Yánez, Antonio; Jácome, Alfredo; Suárez, Joaquín

    2009-01-01

    En este trabajo un reactor biopelícula de membrana tubular micro-porosa de polipropileno aireada ha sido desarrollado para la nitrificación de un agua residual sintética. El reactor ha sido explotado en régimen transitorio y sin presurizar las membranas. El proceso es viable sin presurizar las membranas debido a la auto-aireación de la biopelícula. Sin embrago, sino se renueva la atmósfera interna de las membranas, cuando se ha desarrollado la biopelícula, la nitrificación solo es parcial pro...

  1. Type IV renal tubular acidosis associated with Alport's syndrome.

    OpenAIRE

    Tkácová, R.; Roland, R.; Böör, A.; Kovácová, A.; Lazúrová, I.; Tkác, I.; Hildebrand, T.; Sefara, P.

    1993-01-01

    A case of hereditary nephritis with mild reduction of renal function associated with renal tubular acidosis type IV is described. The patient was admitted with life-threatening hyperkalaemia. To our knowledge, type IV renal tubular acidosis has not been reported previously in association with Alport's syndrome in an adult patient.

  2. Theoretical and experimental investigations of Chinese evacuated tubular solar collectors

    DEFF Research Database (Denmark)

    Qin, Lin; Furbo, Simon

    1999-01-01

    Four different marketed Chinese evacuated tubular solar collectors have been investigated both theoretically and experimentally. The advantages of the investigated solar collectors compared to normal flat plate collectors were elucidated.......Four different marketed Chinese evacuated tubular solar collectors have been investigated both theoretically and experimentally. The advantages of the investigated solar collectors compared to normal flat plate collectors were elucidated....

  3. Complement activation by tubular cells is mediated by properdin binding

    NARCIS (Netherlands)

    Gaarkeuken, E.M.; Siezenga, M.A.; Zuidwijk, K.; Kooten, C. van; Rabelink, T.J.; Daha, M.R.; Berger, S.P.

    2008-01-01

    Activation of filtered complement products on the brush border of the tubular epithelium is thought to be a key factor underlying proteinuria-induced tubulointerstitial injury. However, the mechanism of tubular complement activation is still unclear. Recent studies on mechanisms of complement activa

  4. Modeling constrained sintering of bi-layered tubular structures

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye; Kothanda Ramachandran, Dhavanesan; Ni, De Wei;

    2015-01-01

    Constrained sintering of tubular bi-layered structures is being used in the development of various technologies. Densification mismatch between the layers making the tubular bi-layer can generate stresses, which may create processing defects. An analytical model is presented to describe...... the densification and stress developments during sintering of tubular bi-layered samples. The correspondence between linear elastic and linear viscous theories is used as a basis for derivation of the model. The developed model is first verified by finite element simulation for sintering of tubular bi-layer system....... Furthermore, the model is validated using densification results from sintering of bi-layered tubular ceramic oxygen membrane based on porous MgO and Ce0.9Gd0.1O1.95-d layers. Model input parameters, such as the shrinkage kinetics and viscous parameters are obtained experimentally using optical dilatometry...

  5. Luminal nucleotides are tonic inhibitors of renal tubular transport

    DEFF Research Database (Denmark)

    Leipziger, Jens Georg

    2011-01-01

    PURPOSE OF REVIEW: Extracellular ATP is an essential local signaling molecule in all organ systems. In the kidney, purinergic signaling is involved in an array of functions and this review highlights those of relevance for renal tubular transport. RECENT FINDINGS: Purinergic receptors are expressed...... in all renal tubular segments and their stimulation generally leads to transport inhibition. Recent evidence has identified the tubular lumen as a restricted space for purinergic signaling. The concentrations of ATP in the luminal fluids are sufficiently high to inflict a tonic inhibition of renal...... discovered as an important signaling compartment in which local purinergic signaling determines an inhibitory tone for renal tubular transport. Blocking components of this system leads to tubular hyper-absorption, volume retention and elevated blood pressure....

  6. Multiplicity features of nonadiabatic, autothermal tubular reactors

    Energy Technology Data Exchange (ETDEWEB)

    Lovo, M.; Balakotaiah, V. (Houston Univ., TX (United States). Dept. of Chemical Engineering)

    1992-01-01

    Singularity theory is combined with asymptotic analysis to determine the exact uniqueness-multiplicity boundary and ignition and extinction locus for the non-adiabatic, autothermal tubular reactor model. It is found that the steady-state behavior of the nonadiabatic reactor is described by the two limiting cases of adiabatic and strongly cooled models. The adiabatic case has been examined in a previous study. In this paper, the authors develop limiting models to describe the strongly cooled asymptotes. The authors also classify the different types of bifurcation diagrams of conversion vs. residence time using the results of singularity theory with a distinguished parameter. Analytical criteria are developed for predicting the conditions under which autothermal operation is feasible when heat losses are significant.

  7. TUBULAR PHOTOBIOREACTOR FOR MICROALGAE BIODIESEL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Nkongolo Mulumba

    2012-02-01

    Full Text Available Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year. However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR was designed and achieved a ten times increase in algae concentration. It produced 1g of dry algal biomass per liter of medium within 12 days, with a lipid content of 12% approximately. Healthy algal culture grew well in the TPBR reaching 56x106 cells/mL of culture medium. The 10 fold increase is higher than those reported for open ponds and helical photobioreactor.

  8. Inherited renal tubular defects with hypokalemia

    Directory of Open Access Journals (Sweden)

    Muthukrishnan J

    2009-01-01

    Full Text Available Bartter′s and Gitelman′s syndrome are two ends of a spectrum of inherited renal tubular disorders that present with hypokalemic metabolic alkalosis of varying severity. Clinical features and associated calcium and magnesium ion abnormalities are used to diagnose these cases after excluding other commoner causes. We report on two cases, the first being a young boy, born of pregnancy complicated by polyhydramnios, who had classical dysmorphic features, polyuria, hypokalemia and hypercalciuria and was diagnosed as having Bartter′s syndrome. The second patient is a lady who had recurrent tetany as the only manifestation of Gitelman′s syndrome, which is an unusual presentation. Potassium replacement with supplementation of other deficient ions led to satisfactory clinical and biochemical response.

  9. Tubular initial conditions and ridge formation

    CERN Document Server

    Borysova, M S; Karpenko, Iu A; Shapoval, V M; Sinyukov, Yu M

    2013-01-01

    The 2D azimuth & rapidity structure of the two-particle correlations in relativistic A+A collisions is altered significantly by the presence of sharp inhomogeneities in superdense matter formed in such processes. The causality constraints enforce one to associate the long-range longitudinal correlations observed in a narrow angular interval, the so-called (soft) ridge, with peculiarities of the initial conditions of collision process. This study's objective is to analyze whether multiform initial tubular structures, undergoing the subsequent hydrodynamic evolution and gradual decoupling, can form the soft ridges. Motivated by the flux-tube scenarios, the initial energy density distribution contains the different numbers of high density tube-like boost-invariant inclusions that form a bumpy structure in the transverse plane. The influence of various structures of such initial conditions in the most central A+A events on the collective evolution of matter, resulting spectra, angular particle correlations an...

  10. Size effect of welded thin-walled tubular joints

    OpenAIRE

    Mashiri, Fidelis Rutendo; Zhao, Xiao-Ling; Hirt, Manfred A.; NUSSBAUMER, Alain

    2007-01-01

    This paper clarifies the terminologies used to describe the size effect on fatigue behaviour of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing tubular joints using the hot spot stress method, i.e. thin-walled tubular joints with wall thickness less than 4 mm and thick-walled tubular joints with wall thickness larger than 50 mm or diameter to thickness ratio less than 24. It is the t...

  11. Effect of tamoxifen on spermatogenesis and tubular morphology in rats

    Institute of Scientific and Technical Information of China (English)

    UrbanJ.A.D'Souza

    2004-01-01

    Aim: To observe the effect of tamoxifen citrate on spermatogenesis and tubular morphology in rats.Methods: The effect of tamoxifen citrate i.g. at doses of 400 and 800 mg·kg-1·day-1 in 0.1 mL olive oil for 30 days on seminiferous tubular morphology, seminiferous epithelial diameter (STD), epithelial height (SEH), epididymal sperm count and percent abnormal sperm were evaluated at day 1, 12 and 36 after treatment. Controls were given the vehicle. Results: The higher dose resulted in tubular atrophy on day 31. The STD, SEH and sperm count were decreased and the abnormal spermatozoa increased in a dose-dependent manner with the maximal effect on day 36.Conclusion: Tamoxifen citrate induces tubular shrinkage and atrophy and sperm abnormality at a dose-dependent manner. (Asian J Androl 2004 Sep; 6: 223-226)

  12. Solar Heating Systems with Evacuated Tubular Solar Collector

    DEFF Research Database (Denmark)

    Qin, Lin; Furbo, Simon

    1998-01-01

    Recently different designed evacuated tubular solar collectors were introduced on the market by different Chinese companies. In the present study, investigations on the performance of four different Chinese evacuated tubular collectors and of solar heating systems using these collectors were...... carried out, employing both laboratory test and theoretical calculations. The collectors were tested in a small solar domestic hot water (SDHW) system in a laboratory test facility under realistic conditions. The yearly thermal performance of solar heating systems with these evacuated tubular collectors......, as well as with normal flat-plate collectors was calculated under Danish weather conditions. It is found that, for small SDHW systems with a combi tank design, an increase of 25% -55% net utilized solar energy can be achieved by using these evacuated tubular collectors instead of normal flat...

  13. Device for internal laser welding of tubular elements

    International Nuclear Information System (INIS)

    During the welding, the position of the returning mirror of the laser beam is on the order of a transducer in support on the tubular element to be welded. Application for sleeving PWR steam generator tubes

  14. Elastic Deployable Composite Tubular Roll-Out Boom Project

    Data.gov (United States)

    National Aeronautics and Space Administration — DSS's innovative Elastic Deployable Composite Tubular Roll-Out Boom will provide revolutionary performance when compared to conventional state-of-the-art...

  15. Genetics Home Reference: renal tubular acidosis with deafness

    Science.gov (United States)

    ... Prevention: Hearing Loss in Children Centre for Genetics Education (Australia): Deafness and Hearing Loss Gallaudet University: Laurent Clerc National Deaf Education Center KidsHealth: What's Hearing Loss? MalaCards: renal tubular ...

  16. The Fourier transform of tubular densities

    KAUST Repository

    Prior, C B

    2012-05-18

    We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. © 2012 IOP Publishing Ltd.

  17. Tubular heart valves from decellularized engineered tissue.

    Science.gov (United States)

    Syedain, Zeeshan H; Meier, Lee A; Reimer, Jay M; Tranquillo, Robert T

    2013-12-01

    A novel tissue-engineered heart valve (TEHV) was fabricated from a decellularized tissue tube mounted on a frame with three struts, which upon back-pressure cause the tube to collapse into three coapting "leaflets." The tissue was completely biological, fabricated from ovine fibroblasts dispersed within a fibrin gel, compacted into a circumferentially aligned tube on a mandrel, and matured using a bioreactor system that applied cyclic distension. Following decellularization, the resulting tissue possessed tensile mechanical properties, mechanical anisotropy, and collagen content that were comparable to native pulmonary valve leaflets. When mounted on a custom frame and tested within a pulse duplicator system, the tubular TEHV displayed excellent function under both aortic and pulmonary conditions, with minimal regurgitant fractions and transvalvular pressure gradients at peak systole, as well as well as effective orifice areas exceeding those of current commercially available valve replacements. Short-term fatigue testing of one million cycles with pulmonary pressure gradients was conducted without significant change in mechanical properties and no observable macroscopic tissue deterioration. This study presents an attractive potential alternative to current tissue valve replacements due to its avoidance of chemical fixation and utilization of a tissue conducive to recellularization by host cell infiltration.

  18. Tubular Initial Conditions and Ridge Formation

    Directory of Open Access Journals (Sweden)

    M. S. Borysova

    2013-01-01

    Full Text Available The 2D azimuth and rapidity structure of the two-particle correlations in relativistic A+A collisions is altered significantly by the presence of sharp inhomogeneities in superdense matter formed in such processes. The causality constraints enforce one to associate the long-range longitudinal correlations observed in a narrow angular interval, the so-called (soft ridge, with peculiarities of the initial conditions of collision process. This study's objective is to analyze whether multiform initial tubular structures, undergoing the subsequent hydrodynamic evolution and gradual decoupling, can form the soft ridges. Motivated by the flux-tube scenarios, the initial energy density distribution contains the different numbers of high density tube-like boost-invariant inclusions that form a bumpy structure in the transverse plane. The influence of various structures of such initial conditions in the most central A+A events on the collective evolution of matter, resulting spectra, angular particle correlations and vn-coefficients is studied in the framework of the hydrokinetic model (HKM.

  19. Tubular Steel Arch Stabilized by Textile Membranes

    Directory of Open Access Journals (Sweden)

    Ondrej Svoboda

    2016-10-01

    Full Text Available Tubular steel arch supporting textile membrane roofing is investigated experimentally and numerically. The stabilization effects of the textile membrane on in-plane and out-of-plane behavior of the arch is of primary interest. First a model of a large membrane structure tested in laboratory is described. Prestressed membranes of PVC coated polyester fabric Ferrari® Précontraint 702S were used as a currently standard and excellent material. The test arrangement, loading and resulting load/deflection values are presented. The supporting structure consisted of two steel arch tubes, outer at edge of the membrane and inner supporting interior of the membrane roofing. The stability and strength behavior of the inner tube under both symmetrical and asymmetrical loading was monitored and is shown in some details. Second the SOFiSTiK software was employed to analyze the structural behavior in 3D, using geometrically nonlinear analysis with imperfections (GNIA. The numerical analysis, FE mesh sensitivity, the membrane prestressing and common boundary conditions are validated by test results. Finally a parametrical study concerning stability of mid arch with various geometries in a membrane structure with several supporting arches is presented, with recommendations for a practical design.

  20. A tubular electrode for radiofrequency ablation therapy

    KAUST Repository

    Antunes, Carlos Lemos Lemos Lemos

    2012-07-06

    Purpose – Due to its good mechanical and biocompatibility characteristics, nitinol SEMS is a popular endoprothesis used for relieving stricture problems in hollow organs due to carcinomas. Besides its mechanical application, SEMS can be regarded as well as potential electrode for performing RF ablation therapy on the tumor. The purpose of this work is to perform numerical and experimental analyses in order to characterize the lesion volume induced in biological tissue using this kind of tubular electrode. Design/methodology/approach – Data concerning electrical conductivity and dimension of the damaged tissue after RF ablation procedure were obtained from ex vivo samples. Next, numerical models using 3D finite element method were obtained reassembling the conditions considered at experimentation setup and results were compared. Findings – Numerical and experimental results show that a regular volume of damaged tissue can be obtained considering this type of electrode. Also, results obtained from numerical simulation are close to those obtained by experimentation. Originality/value – SEMSs, commonly used as devices to minimize obstruction problems due to the growth of tumors, may still be considered as an active electrode for RF ablation procedures. A method considering this observation is presented in this paper. Also, numerical simulation can be regarded in this case as a tool for determining the lesion volume.

  1. A distal renal tubular acidosis showing hyperammonemia and hyperlactacidemia

    OpenAIRE

    C. Ripoli; Pinna, A.; Marras, S.; M.L. Fenu; Nurchi, A M

    2012-01-01

    Introduction: distal renal tubular acidosis (dRTA) presents itself with variable clinical manifestations and often with late expressions that impact on prognosis. Case report: A 45-day-old male infant was admitted with stopping growth, difficult feeding and vomiting after meals. Clinical tests and labs revealed a type 1 renal tubular acidosis, even if the first blood tests showed ammonium and lactate increase. We had to exclude metabolic diseases before having a certain diagnosis. Conclusions...

  2. Stresses at weld toes in tubular joints in offshore structures

    OpenAIRE

    Elliott, Kim S.

    1987-01-01

    The accurate prediction of stress concentration factors (SCF) at weld toes is recognised as one of the most important factors in the design, against fatigue failure, of welded tubular joints in offshore structures. The objectives of this work are i) to study the influence of some important tubular joint and weld profile geometric parameters on the elastic SCFs at weld toes, ii) compare these values with strains which could be measured by strain gauges, and iii) to determine plastic-elastic st...

  3. The origin of tubular lava stalactites and other related forms

    OpenAIRE

    Kevin Allred; Carlene Allred

    1998-01-01

    Tubular lava stalactites are often found in lava tubes. Field observations, sample analysis, and comparative studies indicate that these are segregations extruded during cooling from partially crystallized lava al about 1,070 - 1,000 °C. Retrograde boiling (gas pressure) within the lava provides a mechanism to expel the interstitial liquid. In addition to tubular lava stalactites, a variety of other lava features can also result, such as lava helictites, lava coralloids, barnacle-like stretch...

  4. Behaviour of concrete filled steel tubular columns under fire

    Institute of Scientific and Technical Information of China (English)

    查晓雄; 钟善桐

    2002-01-01

    A three dimensional nonlinear FE program is used to calculate the fire resistances of concrete filledsteel tubular columns under fire. The temperature distributions in the circular section fire are decided by solvingthe Fourier Transfer Equation , and the mechanical behaviour and failure of concrete filled steel tubular columnsunder fire are thus investigated, and the effects of several parameters on the fire resistance are analysed. Theresults obtained are in good agreement with the Eurocode.

  5. Tubular atrophy in the pathogenesis of chronic kidney disease progression.

    Science.gov (United States)

    Schelling, Jeffrey R

    2016-05-01

    The longstanding focus in chronic kidney disease (CKD) research has been on the glomerulus, which is sensible because this is where glomerular filtration occurs, and a large proportion of progressive CKD is associated with significant glomerular pathology. However, it has been known for decades that tubular atrophy is also a hallmark of CKD and that it is superior to glomerular pathology as a predictor of glomerular filtration rate decline in CKD. Nevertheless, there are vastly fewer studies that investigate the causes of tubular atrophy, and fewer still that identify potential therapeutic targets. The purpose of this review is to discuss plausible mechanisms of tubular atrophy, including tubular epithelial cell apoptosis, cell senescence, peritubular capillary rarefaction and downstream tubule ischemia, oxidative stress, atubular glomeruli, epithelial-to-mesenchymal transition, interstitial inflammation, lipotoxicity and Na(+)/H(+) exchanger-1 inactivation. Once a a better understanding of tubular atrophy (and interstitial fibrosis) pathophysiology has been obtained, it might then be possible to consider tandem glomerular and tubular therapeutic strategies, in a manner similar to cancer chemotherapy regimens, which employ multiple drugs to simultaneously target different mechanistic pathways.

  6. A cut-off tubular geometry of loop space

    CERN Document Server

    Mukhopadhyay, Partha

    2014-01-01

    Motivated by the computation of loop space quantum mechanics as indicated in [7], here we seek a better understanding of the tubular geometry of loop space ${\\cal L}{\\cal M}$ corresponding to a Riemannian manifold ${\\cal M}$ around the submanifold of vanishing loops. Our approach is to first compute the tubular metric of $({\\cal M}^{2N+1})_{C}$ around the diagonal submanifold, where $({\\cal M}^N)_{C}$ is the Cartesian product of $N$ copies of ${\\cal M}$ with a cyclic ordering. This gives an infinite sequence of tubular metrics such that the one relevant to ${\\cal L}{\\cal M}$ can be obtained by taking the limit $N\\to \\infty$. Such metrics are computed by adopting an indirect method where the general tubular expansion theorem of [12] is crucially used. We discuss how the complete reparametrization isometry of loop space arises in the large-$N$ limit and verify that the corresponding Killing equation is satisfied to all orders in tubular expansion. These tubular metrics can alternatively be interpreted as some n...

  7. Straightening tubular flow for side-by-side visualization.

    Science.gov (United States)

    Angelelli, Paolo; Hauser, Helwig

    2011-12-01

    Flows through tubular structures are common in many fields, including blood flow in medicine and tubular fluid flows in engineering. The analysis of such flows is often done with a strong reference to the main flow direction along the tubular boundary. In this paper we present an approach for straightening the visualization of tubular flow. By aligning the main reference direction of the flow, i.e., the center line of the bounding tubular structure, with one axis of the screen, we are able to natively juxtapose (1.) different visualizations of the same flow, either utilizing different flow visualization techniques, or by varying parameters of a chosen approach such as the choice of seeding locations for integration-based flow visualization, (2.) the different time steps of a time-dependent flow, (3.) different projections around the center line , and (4.) quantitative flow visualizations in immediate spatial relation to the more qualitative classical flow visualization. We describe how to utilize this approach for an informative interactive visual analysis. We demonstrate the potential of our approach by visualizing two datasets from two different fields: an arterial blood flow measurement and a tubular gas flow simulation from the automotive industry. PMID:22034324

  8. Toward high-torque electrostatic tubular motors

    Science.gov (United States)

    Helin, Philippe; Bourbon, Gilles; Minotti, Patrice; Fujita, Hiroyuki

    1999-10-01

    A new generation of electrostatic micro-motors is investigated using cooperation of arrayed direct-drive actuators. Electrostatic scratch-drive actuators (SDA), which combine active frictional contact mechanisms with electrostatic actuation, are particularly analyzed. Active polysilicon sheets of 2*3 mm2 that integrate up to several thousands of electrostatic scratch drive actuators are fabricated by silicon surface micro-machining process. Each elementary actuator provides its contribution according to the driving force superposition principle, with internal forces as high as 105uN are available from this sheet. According to their natural flexibility, active polysilicon sheets can be coated onto large surfaces. A new generation of self-assembled tubular electrostatic micromotors is developed using this concept. A prototype of a cylindrical micromotor, whose external diameter and length are 1 mm and 2 mm, respectively, has been realized through the insertion of a flexible active polysilicon sheet at the rotor/motor- frame interface. After final assembling, the sheet has to be jammed onto the chassis, in order to allow the rotor to be moved with respect to the motor frame. Thus, the sheet must be in close contact with both the rotor and the motor frame, whatever the gap, which separates the two macroscopic parts. The problem related to the micro/macro world interfacing is solved during the design of sheet in allowing an out-of- plane motion of SDA in order to provide a self gap compensation, whatever both the thermal expansion effects and the macroscopic machining tolerances. The expected driving characteristics show the interest of both cooperative arrayed microactuators and direct drive frictional mechanisms.

  9. Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações A brief history review of development on API steels welding for pipeline

    Directory of Open Access Journals (Sweden)

    Jaime Casanova Soeiro Junior

    2013-06-01

    Full Text Available Este trabalho enfoca o desenvolvimento dos aços API para tubulações desde o aço API 5L X42, desenvolvido em 1948, através de laminação a quente seguida de tratamento térmico. Desde então foram feitos diferentes desenvolvimentos visando aumentar a resistência mecânica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adição de elementos de liga, produzindo os aços ARBL e a utilização de rotas de processamento termomecânico durante a laminação. Inicialmente a rota utilizada era a laminação a quente controlada (TMCR, com utilização de elemento microligante como Nb para os aços X60 e o conjunto Nb e V para os aços X65 e X70, associado a uma redução do teor de carbono. Posteriormente foi implantada a rota de fabricação do aço por laminação controlada seguida de resfriamento controlado (TMCP, com redução de carbono e adição de Nb e Ti para os aços X80, e adições de Mo, Nb, Be Ti para os X100. A redução do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes aços são soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores.This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR, together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP manufacturing route was

  10. Proximal tubular dysfunction as an indicator of chronic graft dysfunction

    Directory of Open Access Journals (Sweden)

    N.O.S. Câmara

    2009-03-01

    Full Text Available New strategies are being devised to limit the impact of renal sclerosis on graft function. Individualization of immunosuppression, specifically the interruption of calcineurin-inhibitors has been tried in order to promote better graft survival once chronic graft dysfunction has been established. However, the long-term impact of these approaches is still not totally clear. Nevertheless, patients at higher risk for tubular atrophy and interstitial fibrosis (TA/IF development should be carefully monitored for tubular function as well as glomerular performance. Since tubular-interstitial impairment is an early event in TA/IF pathogenesis and associated with graft function, it seems reasonable that strategies directed at assessing tubular structural integrity and function would yield important functional and prognostic data. The measurement of small proteins in urine such as α-1-microglobulin, N-acetyl-beta-D-glucosaminidase, alpha/pi S-glutathione transferases, β-2 microglobulin, and retinol binding protein is associated with proximal tubular cell dysfunction. Therefore, its straightforward assessment could provide a powerful tool in patient monitoring and ongoing clinical assessment of graft function, ultimately helping to facilitate longer patient and graft survival associated with good graft function.

  11. Fatigue Life of High-Strength Steel Offshore Tubular Joints

    DEFF Research Database (Denmark)

    Petersen, Rasmus Ingomar; Agerskov, Henning; Lopez Martinez, Luis

    1996-01-01

    In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high-strength......In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high...... from Ø 324-610 mm tubes, and the joints were loaded in in-plane bending. Both fatigue tests under constant amplitude loading and tests with a stochastic loading that is realistic in relation to offshore structures, are included in the investigation.A comparison between constant amplitude and variable...... amplitude fatigue test results showed shorter fatigue lives in variable amplitude loading than should be expected from the linear fatigue damage accumulation formula. Furthermore, the fatigue tests on high-strength steel tubular joints showed slightly longer fatigue lives than those obtained in...

  12. Microdiscectomia lombar tubular com o uso de seringas descartáveis de diâmetros progressivos: resultados cirúrgicos Microdiscectomía lumbar tubular con el uso de seringas desechables de diámetros progresivos: resultados quirúrgicos Tubular lumbar microdiscectomy using disposable syringes of progressive diameters: surgical results

    Directory of Open Access Journals (Sweden)

    Diogo Valli Anderle

    2010-06-01

    Full Text Available OBJETIVO: descrever técnica minimamente invasiva para abordagem das hérnias discais com material de baixo custo. MÉTODOS: estudo prospectivo da avaliação dos resultados cirúrgicos de dez pacientes submetidos à microdiscectomia lombar tubular com uso de seringas descartáveis de diâmetros progressivos. RESULTADOS: utilizando os critérios de MacNab modificados, 60% dos pacientes apresentaram resultados considerados excelentes, 30% bons e 10% razoáveis. O tempo médio de cirurgia foi de 70 minutos e o de permanência hospitalar, de 14 horas. CONCLUSÃO: o uso de seringas descartáveis para microdiscectomia tubular foi seguro, de baixo custo e com resultados preliminares semelhantes aos da literatura para o tratamento minimamente invasivo da hérnia discal lombar.OBJETIVO: describir una técnica mínimamente invasiva para el abordaje de las hernias discales con material de bajo costo y de fácil acceso. MÉTODOS: estudio prospectivo de la evaluación de los resultados quirúrgicos de diez pacientes sometidos a una microdiscectomía lumbar utilizando jeringas desechables de diámetros progresivos. RESULTADOS: utilizando los criterios de MacNab cambiados, un 60% de los pacientes tuvieron resultados considerados como excelentes, el 30% buenos y el 10% razonables. El tiempo medio de cirugía fue 70 minutos y de permanencia en el hospital fue de 14 horas. CONCLUSIÓN: los resultados del estudio indican que la técnica es viable, de bajo costo y con resultados similares a los reportados en la literatura para el tratamiento mínimamente invasivo de la hernia discal lumbar.OBJECTIVE: to describe a minimally invasive technique to treat lumbar disc herniation with low-cost material. METHODS: this is a prospective evaluation of ten patients submitted to a tubular lumbar microdiscectomy with disposable syringes for herniated disc. The modified MacNab criteria were used to evaluate the surgical results. RESULTS: according to the modified Mac

  13. The glomerulo-tubular junction: a target in renal diseases.

    Science.gov (United States)

    Lindop, G B M; Gibson, I W; Downie, T T; Vass, D; Cohen, E P

    2002-05-01

    Both global and segmental glomerulopathies may damage specific areas of the renal glomerulus. Diseases associated with glomerular hyperperfusion cause lesions at the vascular pole, while diseases associated with proteinuria often damage the tubular pole. Atubular glomeruli are now known to be plentiful in a variety of common renal diseases. These glomeruli are disconnected from their tubule at the tubular pole and therefore cannot participate in the production of urine. It is widely believed that the disconnection is a result of external compression by periglomerular fibrosis. However, the variable anatomy and cell populations within both the glomerulus and the beginning of the proximal tubule at the glomerulo-tubular junction may also have important roles to play in the response to damage at this sensitive site of the nephron.

  14. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  15. Renal histology and immunopathology in distal renal tubular acidosis.

    Science.gov (United States)

    Feest, T G; Lockwood, C M; Morley, A R; Uff, J S

    1978-11-01

    Renal biospy studies are reported from 10 patients with distal renal tubular acidosis (DRTA). On the biopsies from 6 patients who had associated immunological abnormalities immunofluorescent studies for immunoglobulins, complement, and fibrin were performed. Interstitial cellular infiltration and fibrosis were common findings in patients with and without immunological abnormalities, and were usually associated with nephrocalcinosis and/or recurrent urinary infection. No immune deposits were demonstrated in association with the renal tubules. This study shows that DRTA in immunologically abnormal patients is not caused by tubular deposition of antibody or immune complexes. The possibility of cell mediated immune damage is discussed.

  16. Study of Internal Ballistics of Hepta-Tubular Powders

    Directory of Open Access Journals (Sweden)

    M. C. Gupta

    1959-04-01

    Full Text Available In thin paper a solution of the system of equations in Internal Ballistics of a, conventional gun has been discussed for the hepta-tubular powder. The shot-start pressure is taken diffe- rent from zero and the covolume correction also is taken I. into amount and thus some of the results of Tavernierl who has taken zero shot-start preasure and has neglected the . covolume~omtion, have been generalised. It has been. found out that the maximum pressure in the case of hepta-tubular powders always occurs before the all-burnt position.

  17. Microdiscectomia lombar tubular com o uso de seringas descartáveis de diâmetros progressivos: resultados cirúrgicos Microdiscectomía lumbar tubular con el uso de seringas desechables de diámetros progresivos: resultados quirúrgicos Tubular lumbar microdiscectomy using disposable syringes of progressive diameters: surgical results

    OpenAIRE

    Diogo Valli Anderle; Andrei Fernandes Joaquim; Marcus Vinicius Giglio; Enrico Ghizoni; Luis Adriano Esteves

    2010-01-01

    OBJETIVO: descrever técnica minimamente invasiva para abordagem das hérnias discais com material de baixo custo. MÉTODOS: estudo prospectivo da avaliação dos resultados cirúrgicos de dez pacientes submetidos à microdiscectomia lombar tubular com uso de seringas descartáveis de diâmetros progressivos. RESULTADOS: utilizando os critérios de MacNab modificados, 60% dos pacientes apresentaram resultados considerados excelentes, 30% bons e 10% razoáveis. O tempo médio de cirurgia foi de 70 minutos...

  18. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

    OpenAIRE

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-01-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not...

  19. Subanalytic Bundles and Tubular Neighbourhoods of Zero-Loci

    Indian Academy of Sciences (India)

    Vishwambhar Pati

    2003-08-01

    We introduce the natural and fairly general notion of a subanalytic bundle (with a finite dimensional vector space of sections) on a subanalytic subset of a real analytic manifold , and prove that when is compact, there is a Baire subset of sections in whose zero-loci in have tubular neighbourhoods, homeomorphic to the restriction of the given bundle to these zero-loci.

  20. Theoretical flow investigations of an all glass evacuated tubular collector

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    Heat transfer and flow structures inside all glass evacuated tubular collectors for different operating conditions are investigated by means of computational fluid dynamics. The investigations are based on a collector design with horizontal tubes connected to a vertical 14 manifold channel. Three...

  1. Changes at the glomerulo-tubular junction in renal transplants.

    Science.gov (United States)

    Lee, S J; Howie, A J

    1988-12-01

    We studied by microscopy 377 biopsies, nephrectomies, and necropsy kidneys from 123 human renal transplants. We discovered two common abnormalities of the renal corpuscle, both affecting the glomerulo-tubular junction. Adhesion of the tip of the glomerular tuft to the origin of the tubule, as reported in various non-transplant glomerulopathies, was seen in 197 specimens (52 per cent). This change was common in material showing acute or chronic vascular rejection and glomerulopathy, and was almost universal in transplants that had been in place for over 1 year. Another change at the glomerulo-tubular junction, not previously highlighted, consisted of an infiltrate of lymphocytes or neutrophil polymorphs into the epithelium at the tubular origin. This change was seen in 145 specimens (38 per cent) and was associated with cellular rejection and ascending infection. These changes are of importance because they show two responses of the kidney to injury that involve the glomerulo-tubular junction and thus suggest that this part of the kidney has some specific properties that have been largely neglected up to now.

  2. Renal pathophysiologic role of cortical tubular inclusion bodies.

    Science.gov (United States)

    Radi, Zaher A; Stewart, Zachary S; Grzemski, Felicity A; Bobrowski, Walter F

    2013-01-01

    Renal tubular inclusion bodies are rarely associated with drug administration. The authors describe the finding of renal cortical tubular intranuclear and intracytoplasmic inclusion bodies associated with the oral administration of a norepinephrine/serotonin reuptake inhibitor (NSRI) test article in Sprague-Dawley (SD) rats. Rats were given an NSRI daily for 4 weeks, and kidney histopathologic, ultrastructural pathology, and immunohistochemical examinations were performed. Round eosinophilic intranuclear inclusion bodies were observed histologically in the tubular epithelial cells of the renal cortex in male and female SD rats given the NSRI compound. No evidence of degeneration or necrosis was noted in the inclusion-containing renal cells. By ultrastructural pathology, inclusion bodies consisted of finely granular, amorphous, and uniformly stained nonmembrane-bound material. By immunohistochemistry, inclusion bodies stained positive for d-amino acid oxidase (DAO) protein. In addition, similar inclusion bodies were noted in the cytoplasmic tubular epithelial compartment by ultrastructural and immunohistochemical examination.  This is the first description of these renal inclusion bodies after an NSRI test article administration in SD rats. Such drug-induced renal inclusion bodies are rat-specific, do not represent an expression of nephrotoxicity, represent altered metabolism of d-amino acids, and are not relevant to human safety risk assessment.

  3. Glutamatergic signaling maintains the epithelial phenotype of proximal tubular cells

    NARCIS (Netherlands)

    Bozic, M.; de Rooij, J.; Parisi, E.; Ortega, M.R.; Fernandez, E.; Valdivielso, J.M.

    2011-01-01

    Epithelial-mesenchymal transition (EMT) contributes to the progression of renal tubulointerstitial fibrosis. The N-methyl-d-aspartate receptor (NMDAR), which is present in proximal tubular epithelium, is a glutamate receptor that acts as a calcium channel. Activation of NMDAR induces actin rearrange

  4. Urinary Markers of Tubular Injury in Early Diabetic Nephropathy.

    Science.gov (United States)

    Fiseha, Temesgen; Tamir, Zemenu

    2016-01-01

    Diabetic nephropathy (DN) is a common and serious complication of diabetes associated with adverse outcomes of renal failure, cardiovascular disease, and premature mortality. Early and accurate identification of DN is therefore of critical importance to improve patient outcomes. Albuminuria, a marker of glomerular involvement in early renal damage, cannot always detect early DN. Thus, more sensitive and specific markers in addition to albuminuria are needed to predict the early onset and progression of DN. Tubular injury, as shown by the detection of tubular injury markers in the urine, is a critical component of the early course of DN. These urinary tubular markers may increase in diabetic patients, even before diagnosis of microalbuminuria representing early markers of normoalbuminuric DN. In this review we summarized some new and important urinary markers of tubular injury, such as neutrophil gelatinase associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), N-acetyl-beta-glucosaminidase (NAG), alpha-1 microglobulin (A1M), beta 2-microglobulin (B2-M), and retinol binding protein (RBP) associated with early DN. PMID:27293888

  5. Urinary Markers of Tubular Injury in Early Diabetic Nephropathy

    Science.gov (United States)

    Fiseha, Temesgen; Tamir, Zemenu

    2016-01-01

    Diabetic nephropathy (DN) is a common and serious complication of diabetes associated with adverse outcomes of renal failure, cardiovascular disease, and premature mortality. Early and accurate identification of DN is therefore of critical importance to improve patient outcomes. Albuminuria, a marker of glomerular involvement in early renal damage, cannot always detect early DN. Thus, more sensitive and specific markers in addition to albuminuria are needed to predict the early onset and progression of DN. Tubular injury, as shown by the detection of tubular injury markers in the urine, is a critical component of the early course of DN. These urinary tubular markers may increase in diabetic patients, even before diagnosis of microalbuminuria representing early markers of normoalbuminuric DN. In this review we summarized some new and important urinary markers of tubular injury, such as neutrophil gelatinase associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), N-acetyl-beta-glucosaminidase (NAG), alpha-1 microglobulin (A1M), beta 2-microglobulin (B2-M), and retinol binding protein (RBP) associated with early DN. PMID:27293888

  6. Urinary Markers of Tubular Injury in Early Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Temesgen Fiseha

    2016-01-01

    Full Text Available Diabetic nephropathy (DN is a common and serious complication of diabetes associated with adverse outcomes of renal failure, cardiovascular disease, and premature mortality. Early and accurate identification of DN is therefore of critical importance to improve patient outcomes. Albuminuria, a marker of glomerular involvement in early renal damage, cannot always detect early DN. Thus, more sensitive and specific markers in addition to albuminuria are needed to predict the early onset and progression of DN. Tubular injury, as shown by the detection of tubular injury markers in the urine, is a critical component of the early course of DN. These urinary tubular markers may increase in diabetic patients, even before diagnosis of microalbuminuria representing early markers of normoalbuminuric DN. In this review we summarized some new and important urinary markers of tubular injury, such as neutrophil gelatinase associated lipocalin (NGAL, kidney injury molecule-1 (KIM-1, liver-type fatty acid binding protein (L-FABP, N-acetyl-beta-glucosaminidase (NAG, alpha-1 microglobulin (A1M, beta 2-microglobulin (B2-M, and retinol binding protein (RBP associated with early DN.

  7. Geochemical characterization of tubular alteration features in subseafloor basalt glass

    Science.gov (United States)

    Knowles, Emily; Staudigel, Hubert; Templeton, Alexis

    2013-07-01

    There are numerous indications that subseafloor basalts may currently host a huge quantity of active microbial cells and contain biosignatures of ancient life in the form of physical and chemical basalt glass alteration. Unfortunately, technological challenges prevent us from observing the formation and mineralization of these alteration features in situ, or reproducing tubular basalt alteration processes in the laboratory. Therefore, comprehensive analysis of the physical and chemical traces retained in mineralized tubules is currently the best approach for deciphering a record of glass alteration. We have used a number of high-resolution spectroscopic and microscopic methods to probe the geochemical and mineralogical characteristics of tubular alteration features in basalt glasses obtained from a suite of subseafloor drill cores that covers a range of different collection locations and ages. By combining three different synchrotron-based X-ray measurements - X-ray fluorescence microprobe mapping, XANES spectroscopy, and μ-XRD - with focused ion beam milling and transmission electron microscopy, we have spatially resolved the major and trace element distributions, as well as the oxidation state of Fe, determined the coordination chemistry of Fe, Mn and Ti at the micron-scale, and constrained the secondary minerals within these features. The tubular alteration features are characterized by strong losses of Fe2+, Mn2+, and Ca2+ compared to fresh glass, oxidation of the residual Fe, and the accumulation of Ti and Cu. The predominant phases infilling the alteration regions are Fe3+-bearing silicates dominated by 2:1 clays, with secondary Fe- and Ti-oxides, and a partially oxidized Mn-silicate phase. These geochemical patterns observed within the tubular alteration features are comparable across a diverse suite of samples formed over the past 5-100 Ma, which shows that the microscale mineralization processes are common and consistent throughout the ocean basins and

  8. Luminous effectiveness of tubular light-guides in tropics

    Energy Technology Data Exchange (ETDEWEB)

    Darula, Stanislav; Kittler, Richard; Kocifaj, Miroslav [ICA, Slovak Academy of Sciences, 9, Dubravska Road, 845 03 Bratislava (Slovakia)

    2010-11-15

    Novel tubular light-guides with a transparent hemispherical cupola placed on an unobstructed flat roof collect all sunlight and skylight available at ground level year round. This advantage is heightened in the dry and sunny tropical regions where the sun rises to very high altitudes and often the hours of sunshine last throughout the whole day. Hollow light-guides with very high inner specular reflectances can transport sunbeams downward into the windowless building core very effectively. Due to the tube's diameter and length and multiple reflections, complex illuminance patterns are produced on the underside of the tube, i.e. on top of the glazed ceiling aperture that illuminates the interior space or its working plane. This paper discusses several daylight conditions in tropical interiors illuminated by tubular light-guides. The recently published HOLIGILM calculation program and the user-friendly tool HOLIGILM 4.2 have facilitated the production of this paper. (author)

  9. Screening renal stone formers for distal renal tubular acidosis

    DEFF Research Database (Denmark)

    Osther, P J; Hansen, A B; Røhl, H F

    1989-01-01

    A group of 110 consecutive renal stone formers were screened for distal renal tubular acidosis (RTA) using morning fasting urinary pH (mfUpH) levels followed by a short ammonium chloride loading test in patients with levels above 6.0. In 14 patients (12.7%) a renal acidification defect was noted......; 13 had incomplete and 1 had complete distal RTA. Distal RTA was found particularly in recurrent stone formers (17%), and especially in those with bilateral stone disease, where a distal renal tubular acidification defect was found in 50%. We have been unable to differentiate primary from secondary...... RTA in renal stone formers. Regardless of whether the acidification defect is primary or secondary to stone formation, however, all renal stone formers with distal RTA can expect to benefit from prophylactic alkaline therapy and it is recommended that the screening procedure, which is easy to use...

  10. A Long Term Test of Differently Designed Evacuated Tubular Collectors

    DEFF Research Database (Denmark)

    Fan, Jianhua; Dragsted, Janne; Furbo, Simon

    2008-01-01

    During three years seven differently designed evacuated tubular collectors (ETCs) utilizing solar radiation from all directions have been investigated experimentally. The evacuated tubular solar collectors investigated include one SLL all-glass ETC from Tshinghua Solar Co. Ltd, four heat pipe ETCs...... of the inlet fluid to the collectors have been the same for all collectors. The volume flow rate through each of the collectors is adjusted so that the mean solar collector fluid temperature has been the same for all collectors. Thus a direct performance comparison is possible. The side-by-side tests were...... carried out with different mean solar collector fluid temperatures and in different seasons of the year. The results of the measurements are presented in this paper. The influence of the mean solar collector fluid temperature on the thermal performance of the different collector designs will be discussed...

  11. Acute tubular necrosis in a patient with paroxysmal nocturnal hemoglobinuria

    Directory of Open Access Journals (Sweden)

    Eranga S Wijewickrama

    2013-01-01

    Full Text Available Acute renal failure (ARF is a well-recognized complication of paroxysmal nocturnal hemoglobinuria (PNH. The predominant mechanism is intravascular hemolysis resulting in massive hemoglobinuria ARF. We report a case of acute tubular necrosis (ATN developed in the absence of overwhelming evidence of intravascular hemolysis in a 21-year-old man with anemia, who was eventually diagnosed to have PNH. The patient presented with rapidly deteriorating renal functions in the background of iron deficiency anemia, which was attributed to reflux esophagitis. There was no clinical or laboratory evidence of intravascular hemolysis. Renal biopsy revealed ATN with deposition of hemosiderin in the proximal tubular epithelial cells. Diagnosis of PNH was confirmed with a positive Ham′s test and flow cytometry. Our case emphasizes the need to consider ATN as a possible cause for ARF in patients suspected to have PNH even in the absence of overwhelming evidence of intravascular hemolysis.

  12. Segmental tubular sodium reabsorption in type 1 diabetes

    DEFF Research Database (Denmark)

    Dieperink, H; Eshøj, O; Leyssac, P P;

    1993-01-01

    Segmental tubular sodium reabsorption in Type 1 (insulin-dependent) diabetes was measured in 36 patients in a cross-sectional study including one group (n = 13) without significant albuminuria (UalbV 1), one group (n = 16) with albuminuria in the range from 30 to 300 mg 24 h-1......, and a group (n = 7) with nephropathy (UalbV > 300 mg 24 h-1). Lithium clearance was used to measure end proximal delivery. From end proximal delivery, 51Cr-EDTA clearance (GFR) and sodium clearance, segmental tubular reabsorption was calculated. For all patients, GFR was directly correlated with end proximal...... delivery (r = 0.62, p 1, the direct correlation between GFR and end proximal delivery was also significant (r = 0.77, p

  13. [Primary distal renal tubular acidosis: a case report].

    Science.gov (United States)

    Abdallah, Jihene Ben; Charfeddine, Bassem; Braham, Imen; Neffati, Souhir; Othmen, Leila Ben; Letaief, Affef; Smach, Mohamed Ali; Bourfifa, Zoheier; Dridi, Hedi; Limem, Khalifa

    2011-01-01

    The primary distal renal tubular acidosis is characterized biochemically by the inability of the kidney to produce appropriately acid urine in the presence of systemic metabolic acidosis or after acid loading (e.g. ammonium chloride). It is secondary to defective excretion of H(+) by the cells of the collecting duct. We report the observation of the child MC, 4-year-old, for whom the association of polyuria-polydipsia syndrome, a failure to thrive, nephrolithiasis, hypercalciuria, and especially a high urine pH in the presence of metabolic acidosis did evoke diagnosis of distal renal tubular acidosis. An urine acidification test with ammonium chloride was performed, the urinary pH was always higher than 5.5, thus confirming the diagnosis. PMID:21464016

  14. Dynamic model of microalgal production in tubular photobioreactors.

    Science.gov (United States)

    Fernández, I; Acién, F G; Fernández, J M; Guzmán, J L; Magán, J J; Berenguel, M

    2012-12-01

    A dynamic model for microalgal culture is presented. The model takes into account the fluid-dynamic and mass transfer, in addition to biological phenomena, it being based on fundamental principles. The model has been calibrated and validated using data from a pilot-scale tubular photobioreactor but it can be extended to other designs. It can be used to determine, from experimental measurements, the values of characteristic parameters. The model also allows a simulation of the system's dynamic behaviour in response to solar radiation, making it a useful tool for design and operation optimization of photobioreactors. Moreover, the model permits the identification of local pH gradients, dissolved oxygen and dissolved carbon dioxide; that can damage microalgae growth. In addition, the developed model can map the different characteristic time scales of phenomena inside microalgae cultures within tubular photobioreactors, meaning it is a valuable tool in the development of advanced control strategies for microalgae cultures. PMID:23073105

  15. Inner-tubular physicochemical processes of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    YANG Quanhong; LI Lixiang; CHENG Huiming; WANG Maozhang; BAI Jinbo

    2003-01-01

    Nanosized inner cavities of carbon nanotubes (CNTs) afford quasi-one-dimensional (1D) confined space, in which materials adsorbed or filled are of reactivity greatly different from the materials adsorbed on a planar surface and quite a number of curious physicochemical processes will possibly occur. In other words, 1D CNT nanochannels may serve as "nanosized test tubes". In this article, on the basis of the unique chemical and physical properties of CNTs, the latest progresses of the research on peculiar inner-tubular physicochemical processes of CNTs are briefly reviewed from several aspects. The extraordinary 1D adsorption, capillary filling and nanoscale-confined reaction are discussed in detail. Moreover, the characteristics of "nanosized test tubes" are summarized and many unfamiliar inner cavity chemical processes are expected. Finally, the future direction and challenges on basic researches and potential applications of inner-tubular chemistry of CNTs are discussed.

  16. A distal renal tubular acidosis showing hyperammonemia and hyperlactacidemia

    Directory of Open Access Journals (Sweden)

    C. Ripoli

    2012-08-01

    Full Text Available Introduction: distal renal tubular acidosis (dRTA presents itself with variable clinical manifestations and often with late expressions that impact on prognosis. Case report: A 45-day-old male infant was admitted with stopping growth, difficult feeding and vomiting after meals. Clinical tests and labs revealed a type 1 renal tubular acidosis, even if the first blood tests showed ammonium and lactate increase. We had to exclude metabolic diseases before having a certain diagnosis. Conclusions: blood and urine investigations and genetic tests are fundamental to formulate dRTA diagnosis and to plan follow-up, according to possible phenotypic expressions of recessive and dominant autosomal forms in patients with dRTA.

  17. Tubular separate first wall for ITER-EDA

    International Nuclear Information System (INIS)

    The tubular solution first wall is the most suitable one to cope with the thermal stresses, the use of double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of a crack through both walls: the soft brazing in between wall stops the growth of a crack from one tube to the other. The eddy currents induced in the tubes are low and the Halo current flowing poloidally in the tubes exert a radial pressure which is supported by the blanket box via ad hoc supporting points provided in between first wall and blanket. The tubes can be made of steel to resist a heat flux of up to 1 MW/m2. For higher heat loads copper or vanadium can be used. The tubular first wall can be replaced independently from the blanket. The thermo-hydraulic electro-magnetic and dynamic analysis confirm the viability of the solution proposed

  18. Tubular separate first wall for ITER-EDA

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, A.; Riccardi, B. [Associazione EURATOM-ENEA sulla Fusione, Frascati (Italy); Salpietro, E.; Malavasi, G. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany). NET Design Team

    1994-11-01

    The tubular solution first wall is the most suitable one to cope with the thermal stresses, the use of double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of a crack through both walls: the soft brazing in between wall stops the growth of a crack from one tube to the other. The eddy currents induced in the tubes are low and the Halo current flowing poloidally in the tubes exert a radial pressure which is supported by the blanket box via ad hoc supporting points provided in between first wall and blanket. The tubes can be made of steel to resist a heat flux of up to 1 MW/m{sup 2}. For higher heat loads copper or vanadium can be used. The tubular first wall can be replaced independently from the blanket. The thermo-hydraulic electro-magnetic and dynamic analysis confirm the viability of the solution proposed.

  19. Intrarenal purinergic signaling in the control of renal tubular transport

    DEFF Research Database (Denmark)

    Prætorius, Helle; Leipziger, Jens Georg

    2010-01-01

    Renal tubular epithelial cells receive hormonal input that regulates volume and electrolyte homeostasis. In addition, numerous intrarenal, local signaling agonists have appeared on the stage of renal physiology. One such system is that of intrarenal purinergic signaling. This system involves all ...... of NaCl at the macula densa. This review describes the relevant aspects of local, intrarenal purinergic signaling and outlines its integrative concepts....

  20. ELECTROLYTIC-PLASMA TREATMENT OF INNER SURFACE OF TUBULAR PRODUCTS

    Directory of Open Access Journals (Sweden)

    Yu. G. Alekseev

    2016-01-01

    Full Text Available While manufacturing a number of important tubular products stringent requirements have been imposed on quality of their inner surfaces. The well-known methods for inner surface treatment of pipes include sandblasting, chemical cleaning with acid reagents (oxalic, formic, sulfamic, orthophosphoric acids and electrochemical polishing. Disadvantages of the chemical method are cleaning-up irregularities, high metal removal, limited number of reagent application, complicated selection of reagent chemical composition and concentration, complicated and environmentally harmful recycling of waste chemicals, high cost of reagents. Low productivity at a high cost, as well as hazardous impact on personnel due to high dispersion of abrasive dust are considered as disadvantages of sandblasting. Electrochemical polishing is characterized by the following disadvantages: low processing productivity because supply of high currents is rather difficult due to electrolyte scattering capacity away from the main electrode action zone, limited length of the cavity to be treated due to heating of flexible current leads at operating current densities, application of expensive aggressive electrolytes and high costs of their recycling. A new method for polishing and cleaning of inner surfaces of tubular products based on electrolyte-plasma treatment has been developed. In comparison with the existing methods the proposed methods ensures quality processing with high intensity while applying non-toxic, environmentally friendly and cheap electrolytes. The paper presents results of investigations on technological specific features of electrolyte-plasma treatment for inner surfaces of tubular products: influence of slotted nozzle width, electrolyte flow and rate on stability of gas-vapor blanket, current density and productivity. Results of the research have made it possible to determine modes that provide stability and high productivity in the process of electrolyte

  1. Electrolytic-Plasma Treatment of Inner Surface of Tubular Products

    OpenAIRE

    Yu. G. Alekseev; A. Yu. Korolyov; V. S. Niss; A. E. Parshuta

    2016-01-01

    While manufacturing a number of important tubular products stringent requirements have been imposed on quality of their inner surfaces. The well-known methods for inner surface treatment of pipes include sandblasting, chemical cleaning with acid reagents (oxalic, formic, sulfamic, orthophosphoric acids) and electrochemical polishing. Disadvantages of the chemical method are cleaning-up irregularities, high metal removal, limited number of reagent application, complicated selection of reagent ...

  2. Stator iron loss of tubular permanent-magnet machines

    OpenAIRE

    Amara, Y; Wang, J B; Howe, D

    2005-01-01

    While methods of determining the iron loss in rotating permanent-magnet (PM) machines have been investigated extensively, the study of iron loss in linear machines is relatively poorly documented. This paper describes a simple analytical method to predict flux density waveforms in discrete regions of the laminated stator of a tubular PM machine, and employs an established iron loss model to determine the iron loss components, on both no load and on load. Analytical predictions are compared wi...

  3. Tissue cell assisted fabrication of tubular catalytic platinum microengines

    Science.gov (United States)

    Wang, Hong; Moo, James Guo Sheng; Pumera, Martin

    2014-09-01

    We report a facile platform for mass production of robust self-propelled tubular microengines. Tissue cells extracted from fruits of banana and apple, Musa acuminata and Malus domestica, are used as the support on which a thin platinum film is deposited by means of physical vapor deposition. Upon sonication of the cells/Pt-coated substrate in water, microscrolls of highly uniform sizes are spontaneously formed. Tubular microengines fabricated with the fruit cell assisted method exhibit a fast motion of ~100 bodylengths per s (~1 mm s-1). An extremely simple and affordable platform for mass production of the micromotors is crucial for the envisioned swarms of thousands and millions of autonomous micromotors performing biomedical and environmental remediation tasks.We report a facile platform for mass production of robust self-propelled tubular microengines. Tissue cells extracted from fruits of banana and apple, Musa acuminata and Malus domestica, are used as the support on which a thin platinum film is deposited by means of physical vapor deposition. Upon sonication of the cells/Pt-coated substrate in water, microscrolls of highly uniform sizes are spontaneously formed. Tubular microengines fabricated with the fruit cell assisted method exhibit a fast motion of ~100 bodylengths per s (~1 mm s-1). An extremely simple and affordable platform for mass production of the micromotors is crucial for the envisioned swarms of thousands and millions of autonomous micromotors performing biomedical and environmental remediation tasks. Electronic supplementary information (ESI) available: Related video. See DOI: 10.1039/c4nr03720k

  4. Tubular biomarkers to assess progression of diabetic nephropathy.

    Science.gov (United States)

    Tramonti, Gianfranco; Kanwar, Yashpal S

    2011-05-01

    Despite aggressive management, many patients with diabetic nephropathy still develop end-stage renal disease. Accompanying tubulointerstitial damage is important in the progression of diabetic nephropathy. Markers of tubular damage, such as NGAL, KIM-1, and LFABP, have been proposed for monitoring the effectiveness of therapy. However, Nielsen et al. report a lack of an independent correlation between these biomarkers and glomerular filtration rate. Therefore, these markers seem to offer no improvement in the management of diabetic nephropathy. PMID:21527942

  5. Fatigue behaviour and detailing of slotted tubular connection

    OpenAIRE

    Pereira Baptista, Claudio Alexandre; Borges, Luis; Yadav, Santosh; NUSSBAUMER, Alain

    2015-01-01

    Tubular elements are used in steel structures not only for bracing of other members but also as cross girders diaphragms. They are a competitive solution both due to the lightweight and structural efficiency. Slotted tube-to-plate connections are the natural and most common choice. However, fatigue design of the abrupt transition and differences in the stiffness corresponding to the welded connection, is a critical part of the design. Although such a fatigue connection is classified in differ...

  6. Load introduction into concrete-filled steel tubular columns

    OpenAIRE

    Mollazadeh, Mohammad Hassan

    2015-01-01

    Concrete-Filled Steel Tubular (CFST) columns are increasingly being used because of their many advantages, including high strength, high ductility, and higher fire resistance than conventional steel or concrete columns of the same size. In order to maximise the advantages of CFST column, composite action of the column should be ensured. In realistic structures, the load is not directly applied to the entire CFST column section and is introduced from the beam-column connection. Simple shear c...

  7. Tubular space truss structure for SKITTER 2 robot

    Science.gov (United States)

    Beecham, Richard; Dejulio, Linda; Delorme, Paul; Eck, Eric; Levy, Avi; Lowery, Joel; Radack, Joe; Sheffield, Randy; Stevens, Scott

    1988-05-01

    The Skitter 2 is a three legged transport vehicle designed to demonstrate the principle of a tripod walker in a multitude of environments. The tubular truss model of Skitter 2 is a proof of principal design. The model will replicate the operational capabilities of Skitter 2 including its ability to self-right itself. The project's focus was on the use of light weight tubular members in the final structural design. A strong design for the body was required as it will undergo the most intense loading. Triangular geometry was used extensively in the body, providing the required structural integrity and eliminating the need for cumbersome shear panels. Both the basic femur and tibia designs also relied on the strong geometry of the triangle. An intense literature search aided in the development of the most suitable weld techniques, joints, linkages, and materials required for a durable design. The hinge design features the use of spherical rod end bearings. In order to obtain a greater range of mobility in the tibia, a four-bar linkage was designed which attaches both to the femur and the tibia. All component designs, specifically the body, femur, and the tibia were optimized using the software package IDEAS 3.8A Supertab. The package provided essential deformation and stress analysis information on each component's design. The final structure incurred only a 0.0544 inch deflection in a maximum (worst case) loading situation. The highest stress experienced by any AL6061-T6 tubular member was 1920 psi. The structural integrity of the final design facilitated the use of Aluminum 6061-T6 tubing. The tubular truss structure of Skitter 2 is an effective and highly durable design. All facets of the design are structurally sound and cost effective.

  8. Lipasuria in acute pancreatitis: result of tubular dysfunction?

    Science.gov (United States)

    Muench, R; Buehler, H; Kehl, O; Ammann, R

    1987-01-01

    Lipase, in contrast to amylase, is completely reabsorbed by the proximal tubules after glomerular filtration. Therefore, no lipase is detectable in the unconcentrated urine according to the current opinion. The handling of lipase (detected with an enzyme-immunoassay) by the kidney was investigated in comparison with creatinine, amylase, and beta-2-microglobulin by clearance studies in acute pancreatitis (n = 10), burn injury (n = 4), glomerular proteinuria (n = 8), and controls without evidence of pancreatic or renal diseases (n = 5). In initial stages of acute pancreatitis a measurable clearance of lipase (mean: 49.6 microliters/min, range: 0.5-234) was found in association with corresponding increased clearances of beta-2-microglobulin (mean: 10.5 ml/min, range: 0.02-58.9) and of amylase (mean: 8.9 ml/min, range: 2.4-22.6) in nine of ten patients. This finding is consistent with a defect of tubular function. However, regression analysis failed to show a significant correlation between lipase and beta-2-microglobulin clearance. Repeated measurements during the course of pancreatitis in seven patients showed reversibility of tubular dysfunction. In patients with burn injury a similar elevation of clearances of beta-2-microglobulin and of amylase was found, but tubular dysfunction in this condition was not associated with lipasuria. In glomerular proteinuria a lipase clearance was found in two of five cases with moderate, and in the other three cases with severe impairment of creatinine clearance. beta-2-microglobulin clearance was normal in the former and only slightly elevated in the latter group. In conclusion lipase is measurable in the urine of most patients with acute pancreatitis as a result of a reversible tubular dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. CHARACTERISTICS OF CORN STALK HEMICELLULOSE PYROLYSIS IN A TUBULAR REACTOR

    OpenAIRE

    Gao-Jin Lv; Shu-Bin Wu; Rui Lou

    2010-01-01

    Pyrolysis characteristics of corn stalk hemicellulose were investigated in a tubular reactor at different temperatures, with focus mainly on the releasing profiles and forming behaviors of pyrolysis products (gas, char, and tar). The products obtained were further identified using various approaches (including GC, SEM, and GC-MS) to understand the influence of temperature on product properties and compositions. It was found that the devolatilization of hemicellulose mainly occurred at low tem...

  10. Plastic deformation of tubular crystals by dislocation glide

    Science.gov (United States)

    Beller, Daniel A.; Nelson, David R.

    2016-09-01

    Tubular crystals, two-dimensional lattices wrapped into cylindrical topologies, arise in many contexts, including botany and biofilaments, and in physical systems such as carbon nanotubes. The geometrical principles of botanical phyllotaxis, describing the spiral packings on cylinders commonly found in nature, have found application in all these systems. Several recent studies have examined defects in tubular crystals associated with crystalline packings that must accommodate a fixed tube radius. Here we study the mechanics of tubular crystals with variable tube radius, with dislocations interposed between regions of different phyllotactic packings. Unbinding and separation of dislocation pairs with equal and opposite Burgers vectors allow the growth of one phyllotactic domain at the expense of another. In particular, glide separation of dislocations offers a low-energy mode for plastic deformations of solid tubes in response to external stresses, reconfiguring the lattice step by step. Through theory and simulation, we examine how the tube's radius and helicity affects, and is in turn altered by, the mechanics of dislocation glide. We also discuss how a sufficiently strong bending rigidity can alter or arrest the deformations of tubes with small radii.

  11. Tubular transport and metabolism of cimetidine in chicken kidneys

    International Nuclear Information System (INIS)

    Renal tubular transport and renal metabolism of [14C]cimetidine (CIM) were investigated by unilateral infusion into the renal portal circulation in chickens (Sperber technique). [14C]CIM was actively transported at a rate 88% that of simultaneously infused p-aminohippuric acid, and its transport was saturable. The following organic cations competitively inhibited the tubular transport of [14C]CIM with decreasing potency: CIM, ranitidine, thiamine, procainamide, guanidine and choline. CIM inhibited the transport of [14C]thiamine, [14C]amiloride and [14C]tetraethylammonium. During CIM infusion, two renal metabolites, CIM sulfoxide and hydroxymethylcimetidine, were found in urine. When CIM sulfoxide was infused, its transport efficiency was 32% and not saturable. CIM sulfoxide did ot inhibit the simultaneous renal tubular transport of p-aminohippuric acid or tetraethylammonium. CIM is transported by the organic cation transport system and the kidney metabolizes CIM. Transport of CIM and other cationic drugs could produce a drug interaction to alter drug excretion

  12. A Tubular Biomaterial Construct Exhibiting a Negative Poisson's Ratio.

    Science.gov (United States)

    Lee, Jin Woo; Soman, Pranav; Park, Jeong Hun; Chen, Shaochen; Cho, Dong-Woo

    2016-01-01

    Developing functional small-diameter vascular grafts is an important objective in tissue engineering research. In this study, we address the problem of compliance mismatch by designing and developing a 3D tubular construct that has a negative Poisson's ratio νxy (NPR). NPR constructs have the unique ability to expand transversely when pulled axially, thereby resulting in a highly-compliant tubular construct. In this work, we used projection stereolithography to 3D-print a planar NPR sheet composed of photosensitive poly(ethylene) glycol diacrylate biomaterial. We used a step-lithography exposure and a stitch process to scale up the projection printing process, and used the cut-missing rib unit design to develop a centimeter-scale NPR sheet, which was rolled up to form a tubular construct. The constructs had Poisson's ratios of -0.6 ≤ νxy ≤ -0.1. The NPR construct also supports higher cellular adhesion than does the construct that has positive νxy. Our NPR design offers a significant advance in the development of highly-compliant vascular grafts. PMID:27232181

  13. Evaluation of stress concentration for planar tubular joints

    Institute of Scientific and Technical Information of China (English)

    M.F.GHANAMEH; D.THEVENET; A.ZEGHLOUL

    2006-01-01

    In offshore tubular structures,a typical tubular joint may be subjected to three different types of basic loadings: axial,in-plane bending and out-of-plane bending,through its brace members. Each type will cause a different stress distribution at the joint intersection of structures. Moreover,the actual load condition of a tubular joint can be any combination of the above three basic load cases,for this reason,a combined loading was investigated in addition to these three basic loadings. This load is composed of an axial loading combined with a continuation of rotational bending loading obtained while rotate center of the brace around a circle. Different types of planar joints such as T,Y,X,K,DT,DY,DX,TY,TK,DTX,DTDY,and DTDK,with braces subjected to combined loading,were numerically analyzed to study the effect of those different cases of loading and different types of joints,on the stress concentration zone and values.

  14. A Tubular Biomaterial Construct Exhibiting a Negative Poisson's Ratio.

    Directory of Open Access Journals (Sweden)

    Jin Woo Lee

    Full Text Available Developing functional small-diameter vascular grafts is an important objective in tissue engineering research. In this study, we address the problem of compliance mismatch by designing and developing a 3D tubular construct that has a negative Poisson's ratio νxy (NPR. NPR constructs have the unique ability to expand transversely when pulled axially, thereby resulting in a highly-compliant tubular construct. In this work, we used projection stereolithography to 3D-print a planar NPR sheet composed of photosensitive poly(ethylene glycol diacrylate biomaterial. We used a step-lithography exposure and a stitch process to scale up the projection printing process, and used the cut-missing rib unit design to develop a centimeter-scale NPR sheet, which was rolled up to form a tubular construct. The constructs had Poisson's ratios of -0.6 ≤ νxy ≤ -0.1. The NPR construct also supports higher cellular adhesion than does the construct that has positive νxy. Our NPR design offers a significant advance in the development of highly-compliant vascular grafts.

  15. Intragraft Tubular Vimentin and CD44 Expression Correlate With Long-Term Renal Allograft Function and Interstitial Fibrosis and Tubular Atrophy

    NARCIS (Netherlands)

    J. Kers; Y.C. Xu-Dubois; E. Rondeau; N. Claessen; M.M. Idu; J.J.T.H. Roelofs; F.J. Bemelman; R.J.M. ten Berge; S. Florquin

    2010-01-01

    Background. Development of interstitial fibrosis and tubular atrophy (IF/TA) is the main histologic feature involved in renal allograft deterioration. The aim of this study was to validate whether de novo tubular expression of CD44 (transmembrane glycoprotein) and vimentin (mesenchymal cell marker),

  16. Ileal bladder substitute: antireflux nipple or afferent tubular segment?

    Science.gov (United States)

    Studer, U E; Spiegel, T; Casanova, G A; Springer, J; Gerber, E; Ackermann, D K; Gurtner, F; Zingg, E J

    1991-01-01

    Spheroidal bladder substitutes made from double-folded ileal segments, similar to Goodwin's cup-patch technique, are devoid of major coordinated wall contractions. This, together with the reservoir's direct anastomosis to the membranous urethra, prevents major intraluminal pressure peaks and assures a residue-free voiding of sterile urine. In order to determine whether, under these conditions, an afferent tubular isoperistaltic ileal segment of 20-cm length protects the upper urinary tract as efficiently as an antireflux nipple, 60 male patients who were subjected to radical cystectomy were prospectively randomised to groups in which a bladder substitute was formed together with either of these 2 antireflux devices. An analysis of the results obtained in 20 patients from each group who could be followed for more than 1 year (median observation time 30 and 36 months) showed no differences between the groups in metabolic disturbances, kidney size, reservoir capacity, diurnal and nocturnal urinary continence, the incidence of urinary tract infection or episodes of acute pyelonephritis. Later than 1 year postoperatively, intravenous urograms of the renoureteral units of 25% of the patients with antireflux nipples showed persistent but generally slight dilatation of the upper urinary tracts. This observation was significantly more frequent than it was in patients with afferent tubular segments. Urodynamic and radiographic studies showed that the competence of the antireflux nipples was secured by the raised surrounding intravesical pressure. This, however, also resulted in a transient functional obstruction, and a gradual rise of the basal pressure in the upper urinary tracts was recorded. In patients with afferent ileal tubular segments, contrast medium could be forced upwards into the renal pelvis when the bladder substitutes were overfilled. However, despite raised intravesical pressures, peristalsis in the isoperistaltic afferent tubular segment gradually returned

  17. The molecular interactions between filtered proteins and proximal tubular cells in proteinuria.

    Science.gov (United States)

    Baines, Richard J; Brunskill, Nigel J

    2008-01-01

    Proteinuria is associated with progressive chronic kidney disease and poor cardiovascular outcomes. Exposure of proximal tubular epithelial cells to excess proteins leads to the development of proteinuric nephropathy with tubular atrophy, interstitial inflammation and scarring. Numerous signalling pathways are activated in proximal tubular epithelial cells under proteinuric conditions resulting in gene transcription, altered growth and the secretion of inflammatory and profibrotic mediators. Megalin, the proximal tubular scavenger receptor for filtered macromolecules, has intrinsic signalling functions and may also link albumin to growth factor receptor signalling via regulated intramembrane proteolysis. It now seems that endocytosis is not always a prerequisite for albumin-evoked alterations in proximal tubular cell phenotype. Recent evidence shows the presence of other potential receptors for proteins, such as the neonatal Fc receptor and CD36, in the proximal tubular epithelium. PMID:18849618

  18. Generation of Urinary Albumin Fragments Does Not Require Proximal Tubular Uptake

    OpenAIRE

    Weyer, K.; Nielsen, R; Christensen, E.I.; Birn, H

    2012-01-01

    Urinary albumin excretion is an important diagnostic and prognostic marker of renal function. Both animal and human urine contain large amounts of albumin fragments, but whether these fragments originate from renal tubular degradation of filtered albumin is unknown. Here, we used mice with kidneys lacking megalin and cubilin, the coreceptors that mediate proximal tubular endocytosis of albumin, to determine whether proximal tubular degradation of albumin forms the detectable urinary albumin f...

  19. Drill pipes and casings utilizing multi-conduit tubular; Flerkanals roerstreng

    Energy Technology Data Exchange (ETDEWEB)

    Curlett, H.B.

    1997-04-23

    The invention relates to a multi-conduit tubular having fluid conduits and electrical conduits, with associated surface fluid and electrical commutators, and downhole sensors for providing surface monitors with instantaneous formation data. Each tubular includes a plurality of uniform linear conduits there through, with a gasket seal plate interposed between joined tubular for assuring a high pressure seal between joined conduits. the seal plate includes an intermediate electrical connector for connecting electrical conduit connectors of one tubular to another. A coupling collar with uniform diameter internal coarse and fine threads joins the tubular ends having similar threads by differential thread action without respective tubular rotation. Each tubular end includes an inter-engaging index recess and index lug, and drive recesses and lugs for maintaining angular registry of the tubular string and for driving one drill tubular with another. A fluid commutator includes a rotating shaft with passages connected to the tubular conduits, and rotating in a manifold having annular grooves in communication with the shaft passages and external fluid sources. An adaptor couples each commutator shaft passage to one or more tubular conduits. Slip rings on a quill shaft and stationary brush means provide electrical continuity from the electrical conduit wires to surface equipment. A cross-over sub includes formation parameter sensors and telemetry equipment in a blocked off portion of a fluid conduit. An annular accumulator connected with the well bore annulus applies a pressure thereto in response to downhole sensors to change the effective density of the drill mud. The multi-conduit tubular is further adapted for use as a well casing to provide downhole access of a plurality of fluids and electrical parameter sensors. 28 figs.

  20. Method and tool for contracting tubular members by electro-hydraulic forming before hydroforming

    Science.gov (United States)

    Golovashchenko, Sergey Fedorovich

    2011-03-15

    A tubular preform is contracted in an electro-hydraulic forming operation. The tubular preform is wrapped with one or more coils of wire and placed in a chamber of an electro-hydraulic forming tool. The electro-hydraulic forming tool is discharged to form a compressed area on a portion of the tube. The tube is then placed in a hydroforming tool that expands the tubular preform to form a part.

  1. Inverse Approach to Evaluate the Tubular Material Parameters Using the Bulging Test

    OpenAIRE

    Yulong Ge; Xiaoxing Li; Lihui Lang

    2015-01-01

    Tubular material parameters are required for both part manufactory process planning and finite element simulations. The bulging test is one of the most credible ways to detect the property parameters for tubular material. The inverse approach provides more effective access to the accurate material evaluation than with direct identifications. In this paper, a newly designed set of bulging test tools is introduced. An inverse procedure is adopted to determine the tubular material properties in ...

  2. High temperature fatigue experiments on welded stainless steel tubular elements

    International Nuclear Information System (INIS)

    A test rig has been designed to perform high temperature fatigue experiments on AISI 304 stainless steel tubular elements of 500 mm length, 60.3 mm outer diameter and 2 mm thickness; they are composed by two butt welded tubular elements with welded end flanges. During the experiments it is possible to control the axial strain range, the strain rate and the hold time; the specimen temperature is obtained by an inner heating device, controlled by a series of measuring thermocouples; until now the imposed temperature is 6500C. A preliminary series of experiments has been carried out, with the aim at getting informations for a proper development of the main experimental program, while in the meantime the adjustment of the specimen manufacturing process and its characterization have been performed. Each specimen is welded on the same TIG welding rig, which accounts both for a uniformly reliable welding process and for a proper alignment of the tubular elements. The specimens are then marked by a high precision grid which allows a measurement of the residual localized plastic strain along some generatrix of the specimen and on its thickness. The basic fatigue data have to be measured through a series of standard tests carried out on small size specimens obtained either from the base material and around the welded, heat affected zone. It is also planned to carry out a detailed study on the crack surfaces and to use acoustical emission techniques to properly assess the initial crack propagation. The first results show a marked reduction of the number of cycles at failure, if compared with existing data about small size specimens; the measurement of residual plastic strains shows clearly non-uniform distribution of the plastic zones

  3. High temperature helical tubular receiver for concentrating solar power system

    Science.gov (United States)

    Hossain, Nazmul

    In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional receivers. The helical tubular solar receiver placed at the focused sunlight region meets the higher outlet temperature and efficiency. A vertical tubular receiver is modeled and analyzed for single phase flow with molten salt as heat transfer fluid and alloy625 as heat transfer material. The result is compared to a journal paper of similar numerical and experimental setup for validating our modeling. New types of helical tubular solar receivers are modeled and analyzed with heat transfer fluid turbulent flow in single phase, and granular particle and air plug flow in multiphase to observe the temperature rise in one cyclic operation. The Discrete Ordinate radiation model is used for numerical analysis with simulation software Ansys Fluent 15.0. The Eulerian granular multiphase model is used for multiphase flow. Applying the same modeling parameters and boundary conditions, the results of vertical and helical receivers are compared. With a helical receiver, higher temperature gain of heat transfer fluid is achieved in one cycle for both single phase and multiphase flow compared to the vertical receiver. Performance is also observed by varying dimension of helical receiver.

  4. Stem cell factor expression after renal ischemia promotes tubular epithelial survival.

    Directory of Open Access Journals (Sweden)

    Geurt Stokman

    Full Text Available BACKGROUND: Renal ischemia leads to apoptosis of tubular epithelial cells and results in decreased renal function. Tissue repair involves re-epithelialization of the tubular basement membrane. Survival of the tubular epithelium following ischemia is therefore important in the successful regeneration of renal tissue. The cytokine stem cell factor (SCF has been shown to protect the tubular epithelium against apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: In a mouse model for renal ischemia/reperfusion injury, we studied how expression of c-KIT on tubular epithelium and its ligand SCF protect cells against apoptosis. Administration of SCF specific antisense oligonucleotides significantly decreased specific staining of SCF following ischemia. Reduced SCF expression resulted in impaired renal function, increased tubular damage and increased tubular epithelial apoptosis, independent of inflammation. In an in vitro hypoxia model, stimulation of tubular epithelial cells with SCF activated survival signaling and decreased apoptosis. CONCLUSIONS/SIGNIFICANCE: Our data indicate an important role for c-KIT and SCF in mediating tubular epithelial cell survival via an autocrine pathway.

  5. Amylase/creatinine clearance ratio and tubular proteinuria in acute pancreatitis.

    Science.gov (United States)

    Lankisch, P G; Wolfrum, D I; Koop, H; Winckler, K

    1979-01-01

    Amylase/creatinine clearance ratio (CAm/CCr), urinary protein concentration and urinary protein pattern were studied in 102 samples from 27 patients with acute pancreatitis and in 46 controls. Raised CAm/CCr, proteinuria and a tubular protein pattern were present in 74, 56 and 96% of the patients, respectively. However, CAm/CCr and proteinuria and CAm/CCr and tubular protein pattern were not correlated. These results do not support the suggestion that an elevated CAm/CCr in acute pancreatitis is due to generalized tubular protein reabsorption failure presenting with tubular proteinuria.

  6. Tubular algebras and affine Kac-Moody algebras

    Institute of Scientific and Technical Information of China (English)

    Zheng-xin CHEN; Ya-nan LIN

    2007-01-01

    The purpose of this paper is to construct quotient algebras L(A)C1/I(A) of complex degenerate composition Lie algebras L(A)C1 by some ideals, where L(A)C1 is defined via Hall algebras of tubular algebras A, and to prove that the quotient algebras L(A)C1/I(A) are isomorphic to the corresponding affine Kac-Moody algebras. Moreover, it is shown that the Lie algebra Lre(A)C1 generated by A-modules with a real root coincides with the degenerate composition Lie algebra L(A)C1 generated by simple A-modules.

  7. Tubular algebras and affine Kac-Moody algebras

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The purpose of this paper is to construct quotient algebras L(A)1C/I(A) of complex degenerate composition Lie algebras L(A)1C by some ideals, where L(A)1C is defined via Hall algebras of tubular algebras A, and to prove that the quotient algebras L(A)1C/I(A) are isomorphic to the corresponding affine Kac-Moody algebras. Moreover, it is shown that the Lie algebra Lre(A)1C generated by A-modules with a real root coincides with the degenerate composition Lie algebra L(A)1C generated by simple A-modules.

  8. Partial oxidation of methane to syngas in tubular oxygenpermeable reactor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A dense Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction,in which the separation of oxygen from air and the partial oxidation of methane are integrated in one process. At 875℃,94% of methane conversion, 98% of CO selectivity, 95% of H2 selectivity, and as high as 8.8 mL/(min @cm2) of oxygen flux were obtained. In POM reaction condition, the membrane tube shows a very good stability.

  9. Type 4 renal tubular acidosis in a kidney transplant recipient.

    Science.gov (United States)

    Kulkarni, Manjunath

    2016-02-01

    We report a case of a 66-year-old diabetic patient who presented with muscle weakness 2 weeks after kidney transplantation. Her immunosuppressive regimen included tacrolimus, mycophenolate mofetil, and steroids. She was found to have hyperkalemia and normal anion gap metabolic acidosis. Tacrolimus levels were in therapeutic range. All other drugs such as beta blockers and trimethoprim - sulfamethoxazole were stopped. She did not respond to routine antikalemic measures. Further evaluation revealed type 4 renal tubular acidosis. Serum potassium levels returned to normal after starting sodium bicarbonate and fludrocortisone therapy. Though hyperkalemia is common in kidney transplant recipients, determining exact cause can guide specific treatment. PMID:27105603

  10. On the volume of tubular neighbourhoods of real algebraic varieties

    OpenAIRE

    Martin Lotz

    2012-01-01

    The problem of determining the volume of a tubular neighbourhood has a long and rich history. Bounds on the volume of neighbourhoods of algebraic sets have turned out to play an important role in the probabilistic analysis of condition numbers in numerical analysis. We present a self-contained derivation of bounds on the probability that a random point, chosen uniformly from a ball, lies within a given distance of a real algebraic variety of any codimension. The bounds are given in terms of t...

  11. A Tubular Ionizer as an Efficient Negative Fluorine Ion Source

    International Nuclear Information System (INIS)

    In order to establish the optimal conditions of F- ion production by the tubular ionizer extensive studies of SF6 ionization using the mass separator were performed. The SF6, SF5, SF4, SF3 and F negative ions were observed, and the F- yields as a function of the source temperature, gas pressure and an amount of alkaline metal vapors (K, Na, Ca, Sr, Ba) were measured. The efficiency of F- production of about 40 obtained for the optimal conditions. The delay time and adsorption enthalpy of fluorine on the tantalum surface has been measured for the first time. (author)

  12. Superradiance at the localization-delocalization crossover in tubular chlorosomes

    CERN Document Server

    Molina, Rafael A; Somoza, Alejandro; Chen, Lipeng; Zhao, Yang

    2016-01-01

    We study the effect of disorder on spectral properties of tubular chlorosomes in green sulfur bacteria Cf. aurantiacus. Employing a Frenkel-exciton Hamiltonian with diagonal and off-diagonal disorder consistent with spectral and structural studies, we analyze excitonic localization and spectral statistics of the chlorosomes. A size-dependent localization-delocalization crossover is found to occur as a function of the excitonic energy. The crossover energy region coincides with the more optically active states with maximized superradiance, and is, consequently, more conducive for energy transfer.

  13. Tubular dielectric elastomer actuator for active fluidic control

    Science.gov (United States)

    McCoul, David; Pei, Qibing

    2015-10-01

    We report a novel low-profile, biomimetic dielectric elastomer tubular actuator capable of actively controlling hydraulic flow. The tubular actuator has been established as a reliable tunable valve, pinching a secondary silicone tube completely shut in the absence of a fluidic pressure bias or voltage, offering a high degree of resistance against fluidic flow, and able to open and completely remove this resistance to flow with an applied low power actuation voltage. The system demonstrates a rise in pressure of ∼3.0 kPa when the dielectric elastomer valve is in the passive, unactuated state, and there is a quadratic fall in this pressure with increasing actuation voltage, until ∼0 kPa is reached at 2.4 kV. The device is reliable for at least 2000 actuation cycles for voltages at or below 2.2 kV. Furthermore, modeling of the actuator and fluidic system yields results consistent with the observed experimental dependence of intrasystem pressure on input flow rate, actuator prestretch, and actuation voltage. To our knowledge, this is the first actuator of its type that can control fluid flow by directly actuating the walls of a tube. Potential applications may include an implantable artificial sphincter, part of a peristaltic pump, or a computerized valve for fluidic or pneumatic control.

  14. Surface and interfacial creases in a bilayer tubular soft tissue

    Science.gov (United States)

    Razavi, Mir Jalil; Pidaparti, Ramana; Wang, Xianqiao

    2016-08-01

    Surface and interfacial creases induced by biological growth are common types of instability in soft biological tissues. This study focuses on the criteria for the onset of surface and interfacial creases as well as their morphological evolution in a growing bilayer soft tube within a confined environment. Critical growth ratios for triggering surface and interfacial creases are investigated both analytically and numerically. Analytical interpretations provide preliminary insights into critical stretches and growth ratios for the onset of instability and formation of both surface and interfacial creases. However, the analytical approach cannot predict the evolution pattern of the model after instability; therefore nonlinear finite element simulations are carried out to replicate the poststability morphological patterns of the structure. Analytical and computational simulation results demonstrate that the initial geometry, growth ratio, and shear modulus ratio of the layers are the most influential factors to control surface and interfacial crease formation in this soft tubular bilayer. The competition between the stretch ratios in the free and interfacial surfaces is one of the key driving factors to determine the location of the first crease initiation. These findings may provide some fundamental understanding in the growth modeling of tubular biological tissues such as esophagi and airways as well as offering useful clues into normal and pathological functions of these tissues.

  15. High temperature fatigue experiments on welded stainless steel tubular elements

    International Nuclear Information System (INIS)

    One of the most important problems concerning the design of advanced type reactors regards the high temperature low-cycle fatigue behaviour of structural elements. Design Guides and Codes report reference data, mainly based on strain range versus failure cycles results, which have been determined by various researchers. The data have been obtained through different test techniques applied to different types of specimens. As a consequence such data are not easily correlated; moreover at present an exhaustive series of results about high temperature low-cycle fatigue behaviour of structures is not available. A test rig has been designed to perform high temperature fatigue experiments on AISI 304 stainless steel tubular elements of 500 mm length, 60.3 mm outer diameter and 2 mm thickness, they are composed of two butt welded tubular elements with welded end flanges. During the experiments it is possible to control the axial strain range, the strain rate and the hold time; the specimen temperature is obtained by an inner heating device, controlled by a series of measuring thermocouples; until now the imposed temperature is 6500C. The first results show a marked reduction of the number of cycles at failure, if compared with existing data about small size specimens; the measurement of residual plastic strains shows clearly non-uniform distribution of the plastic zones. (Auth.)

  16. Understanding shape and morphology of unusual tubular starch nanocrystals.

    Science.gov (United States)

    Gong, Bei; Liu, Wenxia; Tan, Hua; Yu, Dehai; Song, Zhaoping; Lucia, Lucian A

    2016-10-20

    Starch nanocrystals (SNC) are aptly described as the insoluble degradation byproducts of starch granules that purportedly display morphologies that are platelet-like, round, square, and oval-like. In this work, we reported the preparation of SNC with unprecedented tubular structures through sulfuric acid hydrolysis of normal maize starch, subsequent exposure to ammonia and relaxation at 4°C. High-resolution transmission electron microscopy observation clearly proved that the SNCs possess tubular nanostructures with polygonal cross-section. After further reviewing the transformations of SNC by acid hydrolysis, ammonia treatment, and curing time at 4°C, a mechanism for T-SNC formation is suggested. It is conjectured that T-SNC gradually self-assembles by combination of smaller platelet-like/square nanocrystals likely loosely aggregated by starch molecular chains from residual amorphous regions. This work paves the way for the pursuit of new approaches for the preparation of starch-based nanomaterials possessing unique morphologies. PMID:27474612

  17. Toward automated cochlear implant insertion using tubular manipulators

    Science.gov (United States)

    Granna, Josephine; Rau, Thomas S.; Nguyen, Thien-Dang; Lenarz, Thomas; Majdani, Omid; Burgner-Kahrs, Jessica

    2016-03-01

    During manual cochlear implant electrode insertion the surgeon is at risk to damage the intracochlear fine-structure, as the electrode array is inserted through a small opening in the cochlea blindly with little force-feedback. This paper addresses a novel concept for cochlear electrode insertion using tubular manipulators to reduce risks of causing trauma during insertion and to automate the insertion process. We propose a tubular manipulator incorporated into the electrode array composed of an inner wire within a tube, both elastic and helically shaped. It is our vision to use this manipulator to actuate the initially straight electrode array during insertion into the cochlea by actuation of the wire and tube, i.e. translation and slight axial rotation. In this paper, we evaluate the geometry of the human cochlea in 22 patient datasets in order to derive design requirements for the manipulator. We propose an optimization algorithm to automatically determine the tube set parameters (curvature, torsion, diameter, length) for an ideal final position within the cochlea. To prove our concept, we demonstrate that insertion can be realized in a follow-the-leader fashion for 19 out of 22 cochleas. This is possible with only 4 different tube/wire sets.

  18. Numerical investigation of cavitation performance on bulb tubular turbine

    Science.gov (United States)

    Sun, L. G.; Guo, P. C.; Zheng, X. B.; Luo, X. Q.

    2016-05-01

    The cavitation flow phenomena may occur in the bulb tubular turbine at some certain operation conditions, which even decrease the performance of units and causes insatiably noise and vibration when it goes worse. A steady cavitating flow numerical simulations study is carried out on the bulb tubular unit with the same blade pitch angle and different guide vane openings by using the commercial code ANSYS CFX in this paper. The phenomena of cavitation induction areas and development process are obtained and draws cavitation performance curves. The numerical results show that the travelling bubble cavity is the main types of cavitation development over a wide operating range of discharge and this type of cavitation begins to sensitive to the value of cavitation number when the discharge exceeding a certain valve, in this condition, it can lead to a severe free bubble formation with the gradually decrement of cavitation number. The reported cavitation performance curves results indicate that the flow blockage incident would happen because of a mount of free bubble formation in the flow passage when the cavity developed to certain extend, which caused head drop behavior and power broken dramatically and influenced the output power.

  19. Nano-tubular cellulose for bioprocess technology development.

    Directory of Open Access Journals (Sweden)

    Athanasios A Koutinas

    Full Text Available Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC justifies its suitability for use in "cold pasteurization" processes and its promoting activity in bioprocessing (fermentation. The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator. Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc.

  20. Advances in tubular solid oxide fuel cell technology

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, S.C. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1996-12-31

    The design, materials and fabrication processes for the earlier technology Westinghouse tubular geometry cell have been described in detail previously. In that design, the active cell components were deposited in the form of thin layers on a ceramic porous support tube (PST). The tubular design of these cells and the materials used therein have been validated by successful electrical testing for over 65,000 h (>7 years). In these early technology PST cells, the support tube, although sufficiently porous, presented an inherent impedance to air flow toward air electrode. In order to reduce such impedance to air flow, the wall thickness of the PST was first decreased from the original 2 mm (the thick-wall PST) to 1.2 mm (the thin-wall PST). The calcia-stabilized zirconia support tube has now been completely eliminated and replaced by a doped lanthanum manganite tube in state-of-the-art SOFCs. This doped lanthanum manganite tube is extruded and sintered to about 30 to 35 percent porosity, and serves as the air electrode onto which the other cell components are fabricated in thin layer form. These latest technology cells are designated as air electrode supported (AES) cells.

  1. Additive manufacturing of patient-specific tubular continuum manipulators

    Science.gov (United States)

    Amanov, Ernar; Nguyen, Thien-Dang; Burgner-Kahrs, Jessica

    2015-03-01

    Tubular continuum robots, which are composed of multiple concentric, precurved, elastic tubes, provide more dexterity than traditional surgical instruments at the same diameter. The tubes can be precurved such that the resulting manipulator fulfills surgical task requirements. Up to now the only material used for the component tubes of those manipulators is NiTi, a super-elastic shape-memory alloy of nickel and titan. NiTi is a cost-intensive material and fabrication processes are complex, requiring (proprietary) technology, e.g. for shape setting. In this paper, we evaluate component tubes made of 3 different thermoplastic materials (PLA, PCL and nylon) using fused filament fabrication technology (3D printing). This enables quick and cost-effective production of custom, patient-specific continuum manipulators, produced on site on demand. Stress-strain and deformation characteristics are evaluated experimentally for 16 fabricated tubes of each thermoplastic with diameters and shapes equivalent to those of NiTi tubes. Tubes made of PCL and nylon exhibit properties comparable to those made of NiTi. We further demonstrate a tubular continuum manipulator composed of 3 nylon tubes in a transnasal, transsphenoidal skull base surgery scenario in vitro.

  2. Tubular Ectasia of the Rete testis: Echographic Findings in 43 Patients; Ectasia tubular de la rete testis: hallazgos ecograficos en 43 pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Aleixandre, A.; Ruiz, F.; Cugat, A. [Hospital Malva-rosa. Valencia (Spain); Fuster, A. V. [Universidad de Valencia. (Spain)

    2003-07-01

    Tubular ectasia of the retetestes is a benign lesion usually associated with epididymal abnormalities. It should be included in the differential diagnosis of intraparenchymatous cystic lesions. Its characteristic echographic image usually allows for a diagnosis without having to perform any other type of exploration. We present a review of 43 patients with tubular ectasia of the rete tests studied ultrasonically during a 7-year period. Intratesticular echographic findings are described, as well as associated extratesticular pathology. (Author) 24 refs.

  3. Spectrum of mutations in the renin-angiotensin system genes in autosomal recessive renal tubular dysgenesis

    DEFF Research Database (Denmark)

    Gribouval, Olivier; Morinière, Vincent; Pawtowski, Audrey;

    2012-01-01

    Autosomal recessive renal tubular dysgenesis (RTD) is a severe disorder of renal tubular development characterized by early onset and persistent fetal anuria leading to oligohydramnios and the Potter sequence, associated with skull ossification defects. Early death occurs in most cases from anuri...... and histological analyses and the characterization of the genetic defects allow genetic counseling and early prenatal diagnosis....

  4. Optimization of production conditions and material characteristics of tubular stabilizer bars

    Science.gov (United States)

    Muhr, R.

    1983-08-01

    Weight reduction of car tubular stabilizer bars is studied. Optimization of prematerial, forming and tempering procedures, and surface treatment are discussed. Steel qualities and production conditions were examined for feasibility with sample stabilizer bars. It is concluded that tubular stabilizer bars can be manufactured and practically used in cars. Tube diameters must not be too small, otherwise the weight saving is minimal.

  5. Effects of receptor-mediated endocytosis and tubular protein composition on volume retention in experimental glomerulonephritis

    DEFF Research Database (Denmark)

    Kastner, Christian; Pohl, Marcus; Sendeski, Mauricio;

    2009-01-01

    and channels involved in volume regulation were altered in GN, and 2) proximal tubular endocytosis may influence locally as well as downstream expressed tubular transporters and channels. Effects of anti-glomerular basement membrane GN were studied in controls and megalin-deficient mice with blunted proximal...

  6. VALIDATION OF SIMULATION MODELS FOR DIFFERENTLY DESIGNED HEAT-PIPE EVACUATED TUBULAR COLLECTORS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Dragsted, Janne; Furbo, Simon

    2007-01-01

    Differently designed heat-pipe evacuated tubular collectors have been investigated theoretically and experimentally. The theoretical work has included development of two TRNSYS [1] simulation models for heat-pipe evacuated tubular collectors utilizing solar radiation from all directions. One model...... is developed for heat-pipe evacuated tubular collectors with flat fins and one model is developed for heat-pipe evacuated tubular collectors with curved fins. The models are characterized by detailed calculations of the heat transfer processes in the fins, by detailed shadow modeling and by fins with selective...... coating on both sides. The input to the models is thus not a simple collector efficiency expression but the actual collector geometry. In this study, the TRNSYS models are validated with measurements for four differently designed heat-pipe evacuated tubular collectors. The collectors are produced...

  7. Renal Function in Diabetic Disease Models: The Tubular System in the Pathophysiology of the Diabetic Kidney

    Science.gov (United States)

    Vallon, Volker; Thomson, Scott C.

    2013-01-01

    Diabetes mellitus affects the kidney in stages. At the onset of diabetes mellitus, in a subset of diabetic patients the kidneys grow large, and glomerular filtration rate (GFR) becomes supranormal, which are risk factors for developing diabetic nephropathy later in life. This review outlines a pathophysiological concept that focuses on the tubular system to explain these changes. The concept includes the tubular hypothesis of glomerular filtration, which states that early tubular growth and sodium-glucose cotransport enhance proximal tubule reabsorption and make the GFR supranormal through the physiology of tubuloglomerular feedback. The diabetic milieu triggers early tubular cell proliferation, but the induction of TGF-β and cyclin-dependent kinase inhibitors causes a cell cycle arrest and a switch to tubular hypertrophy and a senescence-like phenotype. Although this growth phenotype explains unusual responses like the salt paradox of the early diabetic kidney, the activated molecular pathways may set the stage for tubulointerstitial injury and diabetic nephropathy. PMID:22335797

  8. Dysfunctional tubular endoplasmic reticulum constitutes a pathological feature of Alzheimer's disease.

    Science.gov (United States)

    Sharoar, M G; Shi, Q; Ge, Y; He, W; Hu, X; Perry, G; Zhu, X; Yan, R

    2016-09-01

    Pathological features in Alzheimer's brains include mitochondrial dysfunction and dystrophic neurites (DNs) in areas surrounding amyloid plaques. Using a mouse model that overexpresses reticulon 3 (RTN3) and spontaneously develops age-dependent hippocampal DNs, here we report that DNs contain both RTN3 and REEPs, topologically similar proteins that can shape tubular endoplasmic reticulum (ER). Importantly, ultrastructural examinations of such DNs revealed gradual accumulation of tubular ER in axonal termini, and such abnormal tubular ER inclusion is found in areas surrounding amyloid plaques in biopsy samples from Alzheimer's disease (AD) brains. Functionally, abnormally clustered tubular ER induces enhanced mitochondrial fission in the early stages of DN formation and eventual mitochondrial degeneration at later stages. Furthermore, such DNs are abrogated when RTN3 is ablated in aging and AD mouse models. Hence, abnormally clustered tubular ER can be pathogenic in brain regions: disrupting mitochondrial integrity, inducing DNs formation and impairing cognitive function in AD and aging brains. PMID:26619807

  9. MICAL-L1-related and unrelated mechanisms underlying elongated tubular endosomal network (ETEN) in human dendritic cells

    NARCIS (Netherlands)

    Compeer, E.B.; Boes, Marianne

    2014-01-01

    The endosomal pathway constitutes a highly dynamic intracellular transport system, which is composed of vesicular and tubular compartments. Endosomal tubules enable geometry-based discrimination between membrane and luminal content. Extended tubular endosomes were suggested to deliver a steady strea

  10. Characterization of hydrodynamics and mass transfer in two types of tubular electrochemical reactors

    International Nuclear Information System (INIS)

    Highlights: •The flow field of novel vertical-flow tubular electrochemical reactor with mesh electrodes (VTER) and traditional concentric tubular electrochemical reactor with plate electrodes (CTER) were compared. •The relationship between mass transfer coefficients and tube flow velocity and pressure drop in VTER and CTER were obtained. -- Abstract: Electrochemical treatment is an environmentally friendly method of removing pollutants from industrial wastewater. The tubular electrochemical reactor is one kind of electrochemical reactor. The current density distribution on the electrode surface in a traditional concentric tubular reactor is not homogeneous and the working area of the anodes and cathodes is unequal. Therefore, a novel tubular electrochemical reactor based on plug flow fluid orthogonal with mesh plate electrodes is presented. In this work, fluid flow and hydrodynamics of the vertical-flow tubular electrochemical reactor, such as velocity distribution and turbulent intensity distribution using computational fluid dynamics (CFD) method, are studied by comparing them to the traditional one. The electro-oxidation of phenol simulation wastewater treatment was developed to analyze the mass transfer performance of the two types of electrochemical reactors. In the novel tubular electrochemical reactor, due to the presence of mesh electrodes, the velocity distribution tended to be more homogeneous. In fact, the turbulent intensity clearly increased by 200% around the electrode surface. The kinetics of organic compounds removal in the novel tubular electrochemical reactor was also improved. Under the same flow rate, the improvement of the mass transfer coefficient for the novel tubular electrochemical reactor was more than twice that of the traditional tubular electrochemical reactor

  11. [Diagnostic difficulties in a case of constricted tubular visual field].

    Science.gov (United States)

    Dogaru, Oana-Mihaela; Rusu, Monica; Hâncu, Dacia; Horvath, Kárin

    2013-01-01

    In the paper below we present the clinical case of a 48 year old female with various symptoms associated with functional visual disturbance -constricted tubular visual fields, wich lasts from 6 years; the extensive clinical and paraclinical ophthalmological investigations ruled out the presence of an organic disorder. In the present, we suspect a diagnosis of hysteria, still uncertain, wich represented over time a big challenge in psychology and ophthalmology. The mechanisms and reasons for hysteria are still not clear and it could represent a fascinating research theme. The tunnel, spiral or star-shaped visual fields are specific findings in hysteria for patients who present visual disturbance. The question of whether or not a patient with hysterical visual impairment can or cannot "see" is still unresolved.

  12. Scalable Approach for Extrusion and Perfusion of Tubular, Heterotypic Biomaterials

    Science.gov (United States)

    Jeronimo, Mark David

    Soft material tubes are critical in the vasculature of mammalian tissues, forming networks of blood vessels and airways. Homogeneous and heterogeneous hydrogel tubes were extruded in a one-step process using a three layer microfluidic device. Co-axial cylindrical flow of crosslinking solutions and an alginate matrix is generated by a radial arrangement of microfluidic channels at the device's vertical extrusion outlet. The flow is confined and begins a sol-gel transition immediately as it extrudes at velocities upwards of 4 mm/s. This approach allows for predictive control over the dimensions of the rapidly formed tubular structures for outer diameters from 600 microm to 3 mm. A second microfluidic device hosts tube segments for controlled perfusion and pressurization using a reversible vacuum seal. On-chip tube deflection is observed and modeled as a measure of material compliance and circumferential elasticity. I anticipate applications of these devices for perfusion cell culture of cell-laden hydrogel tubes.

  13. Novel Method Used to Inspect Curved and Tubular Structural Materials

    Science.gov (United States)

    Roth, Don J.; Baaklini, George Y.; Carney, Dorothy V.; Bodis, James R.; Rauser, Richard W.

    1999-01-01

    At the NASA Lewis Research Center, a technique for the ultrasonic characterization of plates has been extended to tubes and to curved structures in general. In this technique, one performs measurements that yield a thickness-independent value of the local through-the-thickness speed of sound in a specimen. From such measurements at numerous locations across the specimen, one can construct a map of velocity as a function of location. The gradients of velocity indicated by such a map indicate local through-the-thickness-averaged microstructural parameters that affect the speed of sound. Such parameters include the pore volume fraction, mass density, fiber volume fraction (in the case of a composite material), and chemical composition. Apparatus was designed to apply the technique to tubular and other curved specimens.

  14. Mechanical reliability of geometrically imperfect tubular oxygen transport membranes

    DEFF Research Database (Denmark)

    Kwok, Kawai; Frandsen, Henrik Lund; Søgaard, Martin;

    2014-01-01

    operation. This paper investigates numerically the failure risk of tubular oxygen transport membranes under industrial operating conditions using finite element modeling and Weibull strength analysis. The effects of component manufacturing defects on fracture probability are elucidated by explicit modeling......Mixed ionic and electronic conductors have potential applications as oxygen transport membranes. Realization of the technology is challenged by mechanical reliability of the components which are subjected to stresses arising from oxygen stoichiometry gradients and external overpressure during...... of external pressure, ovality may lead to dramatic stress increase and flattening of oval cross sections. Oval membranes can fail in the long term even though the instantaneous fracture risk is tolerable. Based on industrial relevant conditions, the requirements to the material creep rate and component...

  15. Tubular colonic duplication - review of 1876-1981 literature

    International Nuclear Information System (INIS)

    Four cases of tubular colonic duplication are reported and 53 more are reviewed from 1876-1981 literature. Eighty percent of these patients had other anomalies, most notably genital and bladder duplications. Females outnumbered the males 37 to 20. Fifty percent of patients of either sex had some form of fistulous communication. In no one was the anomaly incompatible with life. Based on the anatomy of distal ends of duplicated colon, the patients are divided in five groups, for each of which the incidence and nature of concomitant anomalies are tabulated. Because of their anatomic complexity, most patients with colonic duplication require clinical evaluation by multiple subspecialists. We have also suggested the sequence and extent to which they should be evaluated by radiologists. (orig.)

  16. [Diagnostic difficulties in a case of constricted tubular visual field].

    Science.gov (United States)

    Dogaru, Oana-Mihaela; Rusu, Monica; Hâncu, Dacia; Horvath, Kárin

    2013-01-01

    In the paper below we present the clinical case of a 48 year old female with various symptoms associated with functional visual disturbance -constricted tubular visual fields, wich lasts from 6 years; the extensive clinical and paraclinical ophthalmological investigations ruled out the presence of an organic disorder. In the present, we suspect a diagnosis of hysteria, still uncertain, wich represented over time a big challenge in psychology and ophthalmology. The mechanisms and reasons for hysteria are still not clear and it could represent a fascinating research theme. The tunnel, spiral or star-shaped visual fields are specific findings in hysteria for patients who present visual disturbance. The question of whether or not a patient with hysterical visual impairment can or cannot "see" is still unresolved. PMID:24701812

  17. Seismic behavior of concrete filled steel tubular arch structures

    Institute of Scientific and Technical Information of China (English)

    Xiong Feng; Sashi K Kunnath; Liu Haowu

    2005-01-01

    Shaking table tests of a 1:10 scale arch model performed to investigate the seismic behavior and resistance of concrete filled steel tubular (CFT) arch structures are described in this paper. The El-Centro record and Shanghai artificial wave were adopted as the input excitation. The entire test process can be divided into three stages depending on the lateral brace configurations, i.e., fully (five) braced, two braces removed, and all braces removed. A total of 46 tests, starting from the elastic state to failure condition, have been conducted. The natural vibration frequencies, responses of acceleration,displacement and strain were measured. From the test results, it is demonstrated that the CFT arch structures are capable of resisting severe ground motions and that CFT arches offer a credible alternative to reinforced concrete arches, especially in regions of high seismic intensity.

  18. Experimental studies of a matrix-tubular solar air collector

    Energy Technology Data Exchange (ETDEWEB)

    Plesca, M.; Varlan, P. [Moldova Technical Univ., Chisinau (Moldova, Republic of). Dept. of Heat and Gas Supply and Ventilation

    2009-06-15

    The most common types of solar air collectors (SAC) are contact-type and matrix-type collectors, with the latter being more efficient. This paper described the design and testing of a matrix-tubular flat solar air collector in the city of Chisinau, Moldova, where the outdoor climatic radiation, heat, and humidity characteristics are favorable for the efficient use of solar energy for building heating and drying applications. The amount of solar energy absorbed by a solar energy air collector depends on the level of insulation and orientation of the solar collector; the absorbance of the absorber surface; and the transmittance of the cover material. This study examined the heat transfer, efficiency, and pressure drop using copper tubes inserted perpendicular to the plane of the absorber plate. The SAC consists of a glazed insulated case, an absorber, and ducting for cold air delivery and hot air discharge. Copper tubes are inserted perpendicular to the plane of the absorber. The absorber is installed in the body of the SAC in such a way that it divides it into an upper channel and lower channel. The channel bottom is lined with aluminium foil that reflects solar radiation coming through the tubes and decreases heat loss in the solar collector. Copper tubes increase the heat exchange surface, create air turbulence and intensify heat transfer. This increases the efficiency of the solar collector. The pressure drop of the matrix-tubular solar air collector is 40 per cent lower than that of the matrix-plate collectors. 11 refs., 2 tabs., 6 figs.

  19. On milling of thin-wall conical and tubular workpieces

    Science.gov (United States)

    Tsai, Mu-Ping; Tsai, Nan-Chyuan; Yeh, Cheng-Wei

    2016-05-01

    Thin-wall tubular-geometry workpieces have been widely applied in aircraft and medical industries. However, due to the special geometry of this kind of workpieces and induced poor machinability, the desired accuracy of machining tends to be greatly degraded, no matter what type of metal-cutting task such as milling, drilling or turning is undertaken. Though numerous research reports are available that the tool path can be planned on the basis of preset surface profile before actual milling operation is performed, it is still difficult to predict the real-time surface profile errors for peripheral milling of thin-wall tubular workpieces. Instead of relying on tool path planning, this research is focused on how to real-time formulate the appropriate applied cutting torque via feedback of spindle motor current. On the other hand, a few suitable cutting conditions which are able to prevent potential break/crack of thin-wall workpieces and enhance productivity but almost retain the same cutting quality is proposed in this research. To achieve this goal, estimated surface profile error on machined parts due to deflections caused by both tool and workpiece is studied at first. Traditionally, by adjusting cutting parameters such as feed rate or cut depth, the deflection of tool or workpiece can be expected not to exceed the specified limit. Instead, an effective feedback control loop is proposed by this work for applying real-time appropriate applied cutting torque to prevent potential break/crack of the thin-wall conical workpieces. The torque estimation approach by spindle motor current feedback and the corresponding fuzzy logic controller are employed. Compared with constant cutting torque during milling operation in tradition manner, it is observed that the time consumption of milling cycle by aid of the aforesaid fuzzy logic controller is greatly shortened while the resulted cutting accuracy upon finish of workpiece can be almost retained.

  20. Design of a Compact and Versatile Bench Scale Tubular Reactor

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2009-06-01

    Full Text Available A compact and versatile laboratory tubular reactor has been designed and fabricated keeping in view of reducing capital cost and minimising energy consumption for gas/vapor-phase heterogeneous catalytic reactions. The reactor is consisted of two coaxial corning glass tubes with a helical coil of glass tube in between the coaxial tubes serving as vaporiser and pre-heater, the catalyst bed is in the inner tube. A schematic diagram of the reactor with detailed dimensions and working principles are described. The attractive feature of the reactor is that the vaporiser, pre-heater and fixed bed reactor are merged in a single compact unit. Thus, the unit minimises separate vaporiser and pre-heater, also avoids separate furnaces used for them and eliminate auxiliary instrumentation such as temperature controller etc. To demonstrate the system operation and illustrate the key features, catalyst screening data and the efficient collection of complete, and accurate intrinsic kinetic data are provided for oxidation of CO over copper chromite catalyst. CO oxidation is an important reaction for auto-exhaust pollution control. The suitability of the versatile nature of the reactor has been ascertained for catalytic reactions where either volatile or vaporizable feeds can be introduced to the reaction zone, e.g. oxidation of iso-octane, reduction of nitric oxide, dehydrogenation of methanol, ethanol and iso-propanol, hydrogenation of nitrobenzene to aniline, etc. Copyright (c 2009 by BCREC. All Rights reserved.[Received: 10 February 2009, Accepted: 9 May 2009][How to Cite: R. Prasad, G. Rattan. (2009. Design of a Compact and Versatile Bench Scale Tubular Reactor. Bulletin of Chemical Reaction Engineering and Catalysis, 4(1: 5-9.  doi:10.9767/bcrec.4.1.1250.5-9][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.1.1250.5-9

  1. Tubular Scaffold with Shape Recovery Effect for Cell Guide Applications

    Directory of Open Access Journals (Sweden)

    Kazi M. Zakir Hossain

    2015-07-01

    Full Text Available Tubular scaffolds with aligned polylactic acid (PLA fibres were fabricated for cell guide applications by immersing rolled PLA fibre mats into a polyvinyl acetate (PVAc solution to bind the mats. The PVAc solution was also mixed with up to 30 wt % β-tricalcium phosphate (β-TCP content. Cross-sectional images of the scaffold materials obtained via scanning electron microscopy (SEM revealed the aligned fibre morphology along with a significant number of voids in between the bundles of fibres. The addition of β-TCP into the scaffolds played an important role in increasing the void content from 17.1% to 25.3% for the 30 wt % β-TCP loading, which was measured via micro-CT (µCT analysis. Furthermore, µCT analyses revealed the distribution of aggregated β-TCP particles in between the various PLA fibre layers of the scaffold. The compressive modulus properties of the scaffolds increased from 66 MPa to 83 MPa and the compressive strength properties decreased from 67 MPa to 41 MPa for the 30 wt % β-TCP content scaffold. The scaffolds produced were observed to change into a soft and flexible form which demonstrated shape recovery properties after immersion in phosphate buffered saline (PBS media at 37 °C for 24 h. The cytocompatibility studies (using MG-63 human osteosarcoma cell line revealed preferential cell proliferation along the longitudinal direction of the fibres as compared to the control tissue culture plastic. The manufacturing process highlighted above reveals a simple process for inducing controlled cell alignment and varying porosity features within tubular scaffolds for potential tissue engineering applications.

  2. The tubular separate first wall for ITER-EDA

    International Nuclear Information System (INIS)

    The first wall (FW) is one of the most loaded plasma-facing components; the heat flux is such that the thermal stresses are the most important design concern. In addition, the FW must resist the eddy current induced during plasma disruption and the high pressure of the coolant and should maintain its properties under a fast neutron flux (dose up to 3 MW m-2).The tubular solution is the most suitable to cope with the thermal stresses; the use of a double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of cracks through both walls: the soft brazing in between the walls stops the growth of cracks from one tube to the other. The eddy currents induced in the tubes are low and the halo current flowing poloidally in the tubes exerts a radial pressure which is supported by the blanket box via supporting points provided in between the FW and the blanket.The tubes are protected with a coating of beryllium or boron carbide against the radiation heat load during disruption, and with a coating of copper against runaway electrons. Fins attached to the tubes are provided to cope with the change in the toroidal width of the FW along the poloidal direction. The fins are also protected by coatings.The tubes can be made of steel to resist a heat flux of up to 1 MW m-2. For higher heat loads, copper or vanadium can be used. The tubular FW can be replaced independently of the blanket.The thermohydraulic, electromagnetic and dynamic analyses confirm the viability of the solution proposed. (orig.)

  3. The tubular separate first wall for ITER-EDA

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, A. [Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Frascati, Rome (Italy); Riccardi, B. [Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Frascati, Rome (Italy); Salpietro, E. [NET Team, Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Malavasi, G. [NET Team, Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    1995-03-01

    The first wall (FW) is one of the most loaded plasma-facing components; the heat flux is such that the thermal stresses are the most important design concern. In addition, the FW must resist the eddy current induced during plasma disruption and the high pressure of the coolant and should maintain its properties under a fast neutron flux (dose up to 3 MW m{sup -2}).The tubular solution is the most suitable to cope with the thermal stresses; the use of a double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of cracks through both walls: the soft brazing in between the walls stops the growth of cracks from one tube to the other. The eddy currents induced in the tubes are low and the halo current flowing poloidally in the tubes exerts a radial pressure which is supported by the blanket box via supporting points provided in between the FW and the blanket.The tubes are protected with a coating of beryllium or boron carbide against the radiation heat load during disruption, and with a coating of copper against runaway electrons. Fins attached to the tubes are provided to cope with the change in the toroidal width of the FW along the poloidal direction. The fins are also protected by coatings.The tubes can be made of steel to resist a heat flux of up to 1 MW m{sup -2}. For higher heat loads, copper or vanadium can be used. The tubular FW can be replaced independently of the blanket.The thermohydraulic, electromagnetic and dynamic analyses confirm the viability of the solution proposed. (orig.).

  4. Nephrotic syndrome and multiple tubular defects in children: an early sign of focal segmental glomerulosclerosis.

    Science.gov (United States)

    McVicar, M; Exeni, R; Susin, M

    1980-12-01

    The nephrotic syndrome is rarely associated with renal tubular defects, and the combination has been reported only in association with advanced renal insufficiency. We report here five children with nephrotic syndrome and multiple tubular defects which evolved when glomular filtration rate ranged between 56 and 90 ml/minute/1.73 m2. The tubular defects were first noted at 3, 4, 4, 7, and 22 months after the onset of the nephrotic syndrome, and renal glycosuria was the first sign in all five children. Glycosuria was intermittent in three patients, constant in two, and ceased with loss of kidney function. Four patients had hyperaminoaciduria and renal tubular acidosis (two of four tested had distal renal tubular acidosis). Three patients had decreased tubular reabsorption of phosphorus and defective maximum concentrating capacity. All five had focal segmental glomerulosclerosis proven by renal biopsy. Over a follow-up period of seven years, all of the children have developed advanced renal insufficiency, four of the five have required dialysis or transplantation within 21 to 72 months after onset, and one has stabilized renal function at 35 ml/minute/1.73 m2. The one patient receiving a kidney transplant has had recurrence of focal segmental glomerulosclerosis in the transplanted kidney and became nephrotic with three subsequent transplants. Our experience suggests that the nephrotic syndrome associated with tubular defects in children forms a subgroup of focal segmental glomerulosclerosis, with rapid progression to renal insufficiency and the potential for recurrence of the lesion in the transplanted kidney.

  5. Navegation system for tubular upper digestive tract Sistema de navegación tubular para vías digestivas altas

    OpenAIRE

    Camilo Andrés Rojas Cifuentes; Cindy Lizeth Carvajal Gaitán; Lerly Yulieth Amaris Serrato; Andrea Del Mar Casallas Mora

    2013-01-01

    The present endoscopy is an uncomfortable experience because these instruments are great size and magnitude, generating feelings of discomfort to the patient during the operation. It’s designed a device to scale, allowing counteract this effect improving the mechanism of endoscopy, being this a more effective and flexible, compared with capsule endoscopy and endoscopy equipment present because will include a biopsy system for analyzing gastroenterological diseases or gastric cancers, with blu...

  6. Hydrothermal growth of NiSe 2 tubular microcrystals assisted by PVA

    Science.gov (United States)

    Fan, Hai; Zhang, Maofeng; Zhang, Xianwen; Qian, Yitai

    2009-10-01

    NiSe 2 tubular microcrystals assembled of nanoparticles have been prepared via a hydrothermal method in an ethanolamine and water mixed solution assisted by polyvinyl alcohol (PVA). The prepared tubular crystals with hexagonal structure are composed of nanoparticles with average diameter of 30 nm. It was found that the phase of the products could be adjusted by the molar ratio of the reactants (Ni/Se), and the morphology of the products could be greatly influenced by the quantity of surfactant PVA. Based on the experimental results, the possible formation mechanism of NiSe 2 tubular microcrystals is also discussed.

  7. MOMENT - ROTATION BEHAVIOUR OF UNIVERSAL BEAM TO TUBULAR COLUMN CONNECTIONS USING REVERSE CHANNEL

    OpenAIRE

    Li, Xue

    2012-01-01

    Steel tubular structures are becoming more widely used in recent years because of their excellent structural performance as well as appearance. For structures with steel hollow section (SHS) columns and concrete filled tubular (CFT) columns, several types of joint may be used to connect to wide flange beams. The topic of this research is a relatively new type of joint, the ‘reverse channel’ connection, in which the legs of a channel are welded to the tube thus converting the closed tubular co...

  8. Proximal tubular bicarbonate reabsorption and PCO2 in chronic metabolic alkalosis in the rat.

    OpenAIRE

    Maddox, D A; Gennari, F J

    1983-01-01

    Studies were undertaken to define the pattern of proximal tubular bicarbonate reabsorption and its relation to tubular and capillary PCO2 in rats with chronic metabolic alkalosis (CMA). CMA was induced by administering furosemide to rats ingesting a low electrolyte diet supplemented with NaHCO3 and KHCO3. Proximal tubular bicarbonate reabsorption and PCO2 were measured in CMA rats either 4-7 or 11-14 d after furosemide injection, in order to study a wide range of filtered bicarbonate loads. A...

  9. Kidney specific protein-positive cells derived from embryonic stem cells reproduce tubular structures in vitro and differentiate into renal tubular cells.

    Directory of Open Access Journals (Sweden)

    Ryuji Morizane

    Full Text Available Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be induced in vitro because of the complexity of kidney structures and the diversity of kidney-component cells. Here, we describe a method of inducing renal tubular cells from mouse embryonic stem cells via the cell purification of kidney specific protein (KSP-positive cells using an anti-KSP antibody. The global gene expression profiles of KSP-positive cells derived from ES cells exhibited characteristics similar to those of cells in the developing kidney, and KSP-positive cells had the capacity to form tubular structures resembling renal tubular cells when grown in a 3D culture in Matrigel. Moreover, our results indicated that KSP-positive cells acquired the characteristics of each segment of renal tubular cells through tubular formation when stimulated with Wnt4. This method is an important step toward kidney disease research using pluripotent stem cells, and the development of kidney regeneration therapies.

  10. Kidney specific protein-positive cells derived from embryonic stem cells reproduce tubular structures in vitro and differentiate into renal tubular cells.

    Science.gov (United States)

    Morizane, Ryuji; Monkawa, Toshiaki; Fujii, Shizuka; Yamaguchi, Shintaro; Homma, Koichiro; Matsuzaki, Yumi; Okano, Hideyuki; Itoh, Hiroshi

    2014-01-01

    Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be induced in vitro because of the complexity of kidney structures and the diversity of kidney-component cells. Here, we describe a method of inducing renal tubular cells from mouse embryonic stem cells via the cell purification of kidney specific protein (KSP)-positive cells using an anti-KSP antibody. The global gene expression profiles of KSP-positive cells derived from ES cells exhibited characteristics similar to those of cells in the developing kidney, and KSP-positive cells had the capacity to form tubular structures resembling renal tubular cells when grown in a 3D culture in Matrigel. Moreover, our results indicated that KSP-positive cells acquired the characteristics of each segment of renal tubular cells through tubular formation when stimulated with Wnt4. This method is an important step toward kidney disease research using pluripotent stem cells, and the development of kidney regeneration therapies.

  11. Biofiksasi CO2 Oleh Mikroalga Chlamydomonas sp dalam Photobioreaktor Tubular

    Directory of Open Access Journals (Sweden)

    Hadiyanto Hadiyanto

    2014-05-01

    Full Text Available Mikroalga memiliki potensi dalam membiofiksasi CO2 dan dapat dimanfaatkan untuk mengurangi kadar CO2 dalam gas pencemar. Pertumbuhan mikroalga sangat dipengaruhi oleh konsentrasi gas CO2 di dalam gas pencemar. Tujuan penelitian ini adalah untuk mengeetahui kemampuan mikroalga Chlamydomonas sp yang dikultivasi dalam photobioreaktor tubular dalam penyerapan gas CO2 serta untuk mengetahui konsentrasi maksimum gas CO2 dalam umpan untuk memproduksi biomasa mikroalga yang optimal. Percobaan dilakukan dnegan memvariasi laju alir dari 0.03 -0.071 L/menit dan konsentrasi CO2 dalam umpan 10-30%. Hasil penelitian menunjukkan bahwa biomasa mikroalga dapat diproduksi dengan maksimal dengan konsentrasi gas CO2 20% dengan laju alir 0.07 L/min. Semakin tinggi laju alir maka produksi biomasa alga semakin besar. Kecepatan pertumbuhan alga maksimum terjadi pada 0.31 /hari. Pada konsentrasi gas CO2 30%, terjadi substrate inhibition yang disebabkan carbon dalam bentuk ion bicarbonate tidak dapat dikonsumsi lagi di dalam kultur alga. Kata kunci : Mikroalga, chlamydomonas sp, biofiksasi CO2, biogas Abstract Microalgae have a potential for CO2 biofixation and therefore can be used to reduce the CO2 concentration in the gas pollutants. Moreover, microalgae growth is strongly affected by the concentration of CO2 in the exhaust gas pollutants. The objective of this research was to investigate the ability of microalgae Chlamydomonas sp which was cultivated in a tubular photobioreactor for CO2 absorption as well as to determine the maximum concentration of CO2 in the feed gas to obtain optimum microalgae biomass. The experiments were performed by varying the gas flow rate of 0.03 -0.071 L / min and the concentration of CO2 in the feed of 10-30%. The results showed that the maximum biomass of microalgae can be produced with CO2 concentration of 20% vol with a flow rate of 0.07 L / min. The result also showed that increasing the gas flow rate, the greater of the production of

  12. EVALUATION OF EVACUATED TUBULAR SOLAR COLLECTORS FOR LARGE SDHW SYSTEMS AND COMBINED SPACE HEATING SYSTEMS

    DEFF Research Database (Denmark)

    Qin, Lin; Furbo, Simon

    1999-01-01

    In the present study, detailed investigations on evacuated tubular solar collectors for large solarheating systems have been carried out. Four types of evacuated tubular solar collectors were used in theinvestigation. Based on laboratory tests, simulation models for the collectors were determined....... Based on thesemodels, the thermal performance of large solar domestic hot water (DHW) systems and combined domestichot water and space heating systems with the four evacuated tubular collectors was determined. To make acomparison with traditional flat-plate collectors, similar simulations were also...... carried out for systems with atypical flat-plate collector. The results show that the thermal advantage of evacuated tubular collectors variesgreatly from system to system, and increases with the solar fraction. Furthermore, the higher the operationtemperature of the collector in the system is...

  13. Experimental research and numerical simulation on impeller exit flow field of bulb tubular pump

    International Nuclear Information System (INIS)

    Three dimensional Laser Doppler Velocimetry (3D-LDV) technique was used to measure the impeller exit flow field of bulb tubular pump, the average velocity distribution of the exit section was obtained, and the energy performance of bulb tubular pump was obtained by model test. The flow field of tubular pump also simulated by CFD based on Navier-Stokes equations and RNG k-ε model. The calculated performance curve was consistent with the model test results, and the calculated velocities of impeller exit compared with the LDV measurement results, it was shown that the distribution of circumferential velocity and axial velocity were close to each other, but the radial velocity deviation between the LDV results and the CFD ones was obviously, the reasons of deviation were analyzed. The experimental results can provide the references for the impeller and diffuser design of tubular pumps, it also can improve the accuracy of calculation and perfect simulation.

  14. Sequential Injection Determination of D-Glucose by Chemiluminescence Using an Open Tubular Immobilised Enzyme Reactor

    DEFF Research Database (Denmark)

    Liu, Xuezhu; Hansen, Elo Harald

    1996-01-01

    A sequential injection analysis system is described that incorporates a nylon tubular reactor containing immobilised glucose oxidase, allowing determination of D-glucose by means of subsequent luminol chemiluminescence detection of the hydrogen peroxide generated in the enzymatic reaction...

  15. A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

    DEFF Research Database (Denmark)

    Sarban, R.; Jones, R. W.; Mace, B. R.;

    2011-01-01

    This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower (TM), is produced in thin sheets...... the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated 'ground...... vibration'. An adaptive feedforward control approach is used to achieve this. The tubular actuator is shown to provide excellent isolation against harmonic vibratory disturbances with attenuation of the resulting 5 and 10 Hz harmonics being 66 and 23 dB, respectively. AVI against a narrow band vibratory...

  16. Diaphragmatic suture with tubular stomach to prevent early delayed gastric emptying after esophagectomy

    Institute of Scientific and Technical Information of China (English)

    Chao Sun; Weiping Shi; Yusheng Shu; Hongcan Shi; Shichun Lu; Kang Wang

    2015-01-01

    Objective The objective of this study was to evaluate the clinical ef icacy of a diaphragmatic suture with tubular stomach to prevent delayed gastric emptying (DGE) after esophagectomy through the cervico-tho-racoabdominal approach. Methods A total of 980 patients with esophageal cancer undergoing esophagectomy through the cer-vico-thoracoabdominal approach were retrospectively included in this study and divided into two groups. Al patients underwent tubular stomach creation (group A; n = 530) or a diaphragmatic suture and tubular stomach creation (group B; n = 450). The incidence of early DGE was observed. Results The incidence of early DGE in group A was significantly higher than that in group B (P Conclusion This observation study suggests that the use of a diaphragmatic suture with tubular stomach through the cervico-thoracoabdominal approach can decrease the incidence of early DGE after esopha-gectomy.

  17. Microbial acetate oxidation in horizontal rotating tubular bioreactor

    Indian Academy of Sciences (India)

    A Slavica; B Šantek; S Novak; V Marić

    2004-06-01

    The aim of this work was to investigate the possibility of conducting a continuous aerobic bioprocess in a horizontal rotating tubular bioreactor (HRTB). Aerobic oxidation of acetate by the action of a mixed microbial culture was chosen as a model process. The microbial culture was not only grown in a suspension but also in the form of a biofilm on the interior surface of HRTB. Efficiency of the bioprocess was monitored by determination of the acetate concentration and chemical oxygen demand (COD). While acetate inlet concentration and feeding rate influenced efficiency of acetate oxidation, the bioreactor rotation speed did not influence the bioprocess dynamics significantly. Gradients of acetate concentration and pH along HRTB were more pronounced at lower feeding rates. Volumetric load of acetate was proved to be the most significant parameter. High volumetric loads (above 2 g acetate l–1 h–1) gave poor acetate oxidation efficiency (only 17 to 50%). When the volumetric load was in the range of 0.60–1.75 g acetate l–1 h–1, acetate oxidation efficiency was 50–75%. At lower volumetric loads (0.14–0.58 g acetate l–1 h–1), complete acetate consumption was achieved. On the basis of the obtained results, it can be concluded that HRTB is suitable for conducting aerobic continuous bioprocesses.

  18. Metachronous tubulovillous and tubular adenomas of the anal canal.

    Science.gov (United States)

    Nozawa, Hiroaki; Ishihara, Soichiro; Morikawa, Teppei; Tanaka, Junichiro; Yasuda, Koji; Ohtani, Kensuke; Nishikawa, Takeshi; Tanaka, Toshiaki; Kiyomatsu, Tomomichi; Kawai, Kazushige; Hata, Keisuke; Kazama, Shinsuke; Yamaguchi, Hironori; Sunami, Eiji; Kitayama, Joji; Fukayama, Masashi; Watanabe, Toshiaki

    2015-01-01

    Anal canal adenoma is an extremely rare disease that has the potential to transform into a malignant tumor. We herein presented a rare case of metachronous multiple adenomas of the anal canal. A 48-year-old woman underwent total colonoscopy following a positive fecal blood test. A 9-mm villous polyp arising from the posterior wall of the anal canal was removed by snare polypectomy. Histologically, the tumor was tubulovillous adenoma with high-grade dysplasia and the cut end was negative for tumor cells. Six years later, an elevated lesion, macroscopically five millimeters in size, was detected in the left wall of the anal canal in a follow-up colonoscopy. Local excision of the tumor was performed, and the lesion was pathologically confirmed to be tubular adenoma with high-grade dysplasia limited to the mucosa. The patient is currently alive without any evidence of recurrence for six months after surgery. Although she had a past history of cervical cancer, the multiple tumors arising in the anal canal were unlikely to be related to human papilloma virus infection. Our case report underscores the importance of careful observations throughout colonoscopy to detect precancerous lesions, particularly in anatomically narrow segments. PMID:26249723

  19. A review of the ultimate strength of tubular framed structures

    Energy Technology Data Exchange (ETDEWEB)

    Bolt, H.M.; Billington, C.J.; Ward, J.K.

    1996-10-01

    This review of the ultimate strength of tubular framed structures has been prepared for the Health and Safety Executive (HSE) by Billington Osborne-Moss Engineering Limited (BOMEL). A numerical capability to predict the nonlinear response of jacket structures has been developed over the last decade in parallel with experimental investigations. It is now being applied to assure the continued integrity of installations beyond the design event in circumstances of extreme environmental loading or damage. A recent investigation has confirmed that an extreme event static pushover analysis generally suffices to demonstrate a structure`s resistance to the cyclic loading of the full storm. This report draws together the results from published investigations and identifies key factors contributing to system reserve. It is shown that bracing configurations and relative member properties are important influences. From the work presented, it is demonstrated that many jacket analyses embody simplifying assumptions, and features such as loading asymmetry, joint nonlinearity, foundation interactions, global deflection criteria etc, are neglected. Specific examples highlighted in the review illustrate their potential importance and systematic sensitivity evaluations are therefore recommended. (UK)

  20. Remote panoramic radiography of small diameter tubular butt welds

    International Nuclear Information System (INIS)

    The application of low energy isotopes has been considered for the radiographic inspection of tubular butt welds in small diameter thin walled heat exchanger tubing. Four isotopes were selected from an initial list, after consideration of gamma ray energy spectrum, half life, specific activity, availability and cost. The experimental work undertaken to assess image contrast, inherent unsharpness and weld image sensitivity is briefly discussed and the relative insensitivity of conventional British Standard wire type image quality indicators to changes in radiographic definition is demonstrated. A design study undertaken to identify a suitable remote delivery/positioning system for panoramic radiography is also reported. This system is based upon conventional projection equipment with a flexible guide tube and inflatable source positioning device, which can incorporate a suitable image quality indicator. The equipment should prove capable of greatly extending the application of panoramic radiography during heat exchanger manufacture, particularly in situations where geometric restrictions limit the application of ultrasonic techniques, or where clarification of ultrasonic defect indication is required. Thus the system will provide a useful addition to the NDE techniques currently available for the implementation of the stringent quality assurance requirements of the nuclear industry. (author)

  1. Tubularized incised plate urethroplasty results in patients with proximal hypospadias

    Directory of Open Access Journals (Sweden)

    Yasin Aydoğmuş

    2015-12-01

    Full Text Available Objective: To evaluate the results of the patients with primary proximal hypospadias repaired by “tubularized incised plate” urethroplasty (TIPU. Methods: Thirty-three patients who were operated with TIPU technique in our clinic between 2003-2011 for primary hypospadias with proximal penile and penoscrotal meatus were retrospectively evaluated. Evaluation of the success in this study was, “voiding without fistula”. Results: Mean age was 6.82±3.07 (1-13. Fifteen patients (45.4% had penoscrotal and 18 patients (54.6% had proximal penil meatus. Postoperative success was evaluated with direct vision of voiding at the time of un-catheterization, 2 weeks and 6 months after un-catheterization. Success rates were 5/15 and 10/18 after the first repair in the level penoscrotal and proximal penil, respectively. Overall success rate was 45.5% after the first repair. Patients with urethral fistula after first repair were undergone second repair, success rates were increased to 9/15 and 16/18 in the levels of penoscrotal and proximal penil, respectively. Overall success rate after second repair was 75.8%. Conclusion: TIPU may be confidently applied for the patients with proximal hypopadias in experienced clinics, if there is not an uretral cordi or/and abnormality in the development of urethral plate.

  2. The thermal decomposition of methane in a tubular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Atsushi; Steinberg, M.

    1992-01-01

    The reaction rate of methane decomposition using a tubular reactor having a 1 inch inside diameter with an 8 foot long heated zone was investigated in the temperature range of 700 to 900 C with pressures ranging from 28.2 to 56.1 atm. Representing the rate by a conventional model, {minus}dC{sub CH4}/dt= k1 C{sub CH4} {minus}k2 C{sub H2}{sup 2}, the rate constant k1 for methane decomposition was determined. The activation energy, 31.3 kcal/mol, calculated by an Arrhenius Plot was lower than for previously published results for methane decomposition. This result indicates that submicron particles found in the reactor adhere to the inside of the reactor and these submicron high surface area carbon particles tend to catalyze the methane decomposition. The rate constant has been found to be approximately constant at 900 C with pressure range cited above. The rate of methane decomposition increases with methane partial pressure in first-order. The rate of the methane decomposition is favored by higher temperatures and pressures while the thermochemical equilibrium of methane decomposition is favored by lower pressures. 8 refs., 7 figs., 2 tabs.

  3. Ammonia-water absorption in vertical tubular absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Sieres, Jaime; Rodriguez, Cristobal; Vazquez, Manuel [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Campus Lagoas-Marcosende, No 9, 36200 Vigo (Spain)

    2005-03-01

    This paper presents a detailed analysis of the heat and mass transfer processes during the absorption of ammonia into water in a co-current vertical tubular absorber. The absorber configuration is of the shell and tubes type. The absorption process progresses as the vapour and liquid contact inside the tubes. Water is used as the absorber cooling medium. A differential mathematical model has been developed on the basis of mass and energy balances and heat and mass transfer equations, in order to provide further understanding of the absorber behaviour. The model takes into account separately for the churn, slug and bubbly flow patterns experimentally forecasted in this type of absorption processes inside vertical tubes and considers the simultaneous heat and mass transfer processes in both liquid and vapour phases, as well as heat transfer to the cooling medium. The model equations have been solved using the finite-difference method. Results obtained for specific data are depicted to show local values of the most important variables all along the absorber length. Parametric analyses have been performed to show the influence of design parameters and operating conditions on the absorber performance. The effect of the heat and mass transfer coefficients has also been evaluated. (authors)

  4. STUDY THE CREEP OF TUBULAR SHAPED FIBER REINFORCED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Najat J. Saleh

    2013-05-01

    Full Text Available Inpresent work tubular –shaped fiber reinforced composites were manufactured byusing two types of resins ( Epoxy and unsaturated polyester and separatelyreinforced with glass, carbon and kevlar-49 fibers (filament and woven roving,hybrid reinforcement composites of these fibers were also prepared. The fiberswere wet wound on a mandrel using a purposely designed winding machine,developed by modifying an ordinary lathe, in winding angle of 55° for filament. A creep test was made of either the fulltube or specimens taken from it. Creep was found to increase upon reinforcementin accordance to the rule of mixture and mainly decided by the type of singleor hybridized fibers. The creep behavior, showed that the observed strain tendsto appear much faster at higher temperature as compared with that exhibited atroom temperate. The creep rate also found to be depending on fiber type, matrixtype, and the fiber /matrix bonding. The creep energy calculated fromexperimental observations was found to exhibit highest value for hybridizedreinforcement.

  5. Steady State Response Analysis of a Tubular Piezoelectric Print Head.

    Science.gov (United States)

    Chang, Jiaqing; Liu, Yaxin; Huang, Bo

    2016-01-12

    In recent years, inkjet technology has played an important role in industrial materials printing and various sensors fabrication, but the mechanisms of the inkjet print head should be researched more elaborately. The steady state deformation analysis of a tubular piezoelectric print head, which can be classified as a plane strain problem because the radii of the tubes are considerably smaller than the lengths, is discussed in this paper. The geometric structure and the boundary conditions are all axisymmetric, so a one-dimensional mathematical model is constructed. By solving the model, the deformation field and stress field, as well as the electric potential distribution of the piezoelectric tube and glass tube, are obtained. The results show that the deformations are on the nanometer scale, the hoop stress is larger than the radial stress on the whole, and the potential is not linearly distributed along the radial direction. An experiment is designed to validate these computations. A discussion of the effect of the tubes' thicknesses on the system deformation status is provided.

  6. A single vibration mode tubular piezoelectric ultrasonic motor.

    Science.gov (United States)

    He, Siyuan; Chiarot, Paul R; Park, Soonho

    2011-05-01

    A novel tubular ultrasonic motor is presented that uses only a single vibration bending mode of a piezoelectric tube to generate rotation. When the piezoelectric tube bends, the diagonal motion of points on selected areas at the ends of the tube generates forces with tangential components along the same circumferential direction, driving the rotors to rotate. Bi-directional motion is achieved by simply switching the direction of bending. Because only one vibration mode is used, the motor requires only one driving signal and no vibration mode coupling is needed, simplifying the design, fabrication, assembly, and operation of the device. Two prototypes [one with cut-in lead zirconate titanate (PZT) teeth and one with added metal teeth] were built and tested using PZT tubes available to the authors. The tubes have an outside diameter of 6.6 mm, inner diameter of 5.0 mm, and length of 25.4 mm. The working frequencies of the two motors are 27.6 and 23.5 kHz. The motors achieved a maximum no-load speed of 400 rpm and a stall torque of 300 μN·m. PMID:21622060

  7. Etiopathology of chronic tubular, glomerular and renovascular nephropathies: Clinical implications

    Directory of Open Access Journals (Sweden)

    Ortiz Alberto

    2011-01-01

    Full Text Available Abstract Chronic kidney disease (CKD comprises a group of pathologies in which the renal excretory function is chronically compromised. Most, but not all, forms of CKD are progressive and irreversible, pathological syndromes that start silently (i.e. no functional alterations are evident, continue through renal dysfunction and ends up in renal failure. At this point, kidney transplant or dialysis (renal replacement therapy, RRT becomes necessary to prevent death derived from the inability of the kidneys to cleanse the blood and achieve hydroelectrolytic balance. Worldwide, nearly 1.5 million people need RRT, and the incidence of CKD has increased significantly over the last decades. Diabetes and hypertension are among the leading causes of end stage renal disease, although autoimmunity, renal atherosclerosis, certain infections, drugs and toxins, obstruction of the urinary tract, genetic alterations, and other insults may initiate the disease by damaging the glomerular, tubular, vascular or interstitial compartments of the kidneys. In all cases, CKD eventually compromises all these structures and gives rise to a similar phenotype regardless of etiology. This review describes with an integrative approach the pathophysiological process of tubulointerstitial, glomerular and renovascular diseases, and makes emphasis on the key cellular and molecular events involved. It further analyses the key mechanisms leading to a merging phenotype and pathophysiological scenario as etiologically distinct diseases progress. Finally clinical implications and future experimental and therapeutic perspectives are discussed.

  8. The fouling in the tubular heat exchanger of Algiers refinery

    Science.gov (United States)

    Harche, Rima; Mouheb, Abdelkader; Absi, Rafik

    2016-05-01

    Crude oil fouling in refinery preheat exchangers is a chronic operational problem that compromises energy recovery in these systems. Progress is hindered by the lack of quantitative knowledge of the dynamic effects of fouling on heat exchanger transfer and pressure drops. In subject of this work is an experimental determination of the thermal fouling resistance in the tubular heat exchanger of the crude oil preheats trains installed in an Algiers refinery. By measuring the inlet and outlet temperatures and mass flows of the two fluids, the overall heat transfer coefficient has been determined. Determining the overall heat transfer coefficient for the heat exchanger with clean and fouled surfaces, the fouling resistance was calculated. The results obtained from the two cells of exchangers studies, showed that the fouling resistance increased with time presented an exponential evolution in agreement with the model suggested by Kern and Seaton, with the existence of fluctuation caused by the instability of the flow rate and the impact between the particles. The bad cleaning of the heat exchangers involved the absence of the induction period and caused consequently, high values of the fouling resistance in a relatively short period of time.

  9. Design and Analysis of Tubular Permanent Magnet Linear Wave Generator

    Directory of Open Access Journals (Sweden)

    Jikai Si

    2014-01-01

    Full Text Available Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG.

  10. Gradient-based enhancement of tubular structures in medical images.

    Science.gov (United States)

    Moreno, Rodrigo; Smedby, Örjan

    2015-12-01

    Vesselness filters aim at enhancing tubular structures in medical images. The most popular vesselness filters are based on eigenanalyses of the Hessian matrix computed at different scales. However, Hessian-based methods have well-known limitations, most of them related to the use of second order derivatives. In this paper, we propose an alternative strategy in which ring-like patterns are sought in the local orientation distribution of the gradient. The method takes advantage of symmetry properties of ring-like patterns in the spherical harmonics domain. For bright vessels, gradients not pointing towards the center are filtered out from every local neighborhood in a first step. The opposite criterion is used for dark vessels. Afterwards, structuredness, evenness and uniformness measurements are computed from the power spectrum in spherical harmonics of both the original and the half-zeroed orientation distribution of the gradient. Finally, the features are combined into a single vesselness measurement. Alternatively, a structure tensor that is suitable for vesselness can be estimated before the analysis in spherical harmonics. The two proposed methods are called Ring Pattern Detector (RPD) and Filtered Structure Tensor (FST) respectively. Experimental results with computed tomography angiography data show that the proposed filters perform better compared to the state-of-the-art.

  11. The tubular separate first wall for ITER EDA

    International Nuclear Information System (INIS)

    The first wall is one of the most loaded plasma-facing components, the heat flux is such that the thermal stresses are the most important design concern. In addition, the First Wall shall resist the eddy current induced plasma disruption, the high pressure of the coolant without leaking (-6 Torr-lit/sec.) and it should maintain its properties under fast neutron flux (dose up to 3 MW/m2). The tubular solution is the most suitable one to cope with the thermal stresses, the use of double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of a crack through both walls: the soft brazing in between walls stops the growth of a crack from one tube to the other. The eddy currents induced in the tubes are low and the Halo current flowing poloidally in the tubes exert a radial pressure which is supported by the blanket box via ad hoc supporting points provided in between first wall and blanket. Conclusions from the thermo-hydraulic analysis and the electromagnetic analysis will be presented including dynamic analysis. Also results of preliminary technological tests on coatings will be discussed

  12. The tubular separate first wall for ITER EDA

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, A.; Riccardi, B. [Centro Ricerche Energia Frascati, Rome (Italy); Salpietro, E. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    1994-12-31

    The first wall is one of the most loaded plasma-facing components, the heat flux is such that the thermal stresses are the most important design concern. In addition, the First Wall shall resist the eddy current induced plasma disruption, the high pressure of the coolant without leaking (<10{sup {minus}6} Torr-lit/sec.) and it should maintain its properties under fast neutron flux (dose up to 3 MW/m{sup 2}). The tubular solution is the most suitable one to cope with the thermal stresses, the use of double wall reduces the risk of leaks inside the vacuum vessel by avoiding the growth of a crack through both walls: the soft brazing in between walls stops the growth of a crack from one tube to the other. The eddy currents induced in the tubes are low and the Halo current flowing poloidally in the tubes exert a radial pressure which is supported by the blanket box via ad hoc supporting points provided in between first wall and blanket. Conclusions from the thermo-hydraulic analysis and the electromagnetic analysis will be presented including dynamic analysis. Also results of preliminary technological tests on coatings will be discussed.

  13. Mechanism of hydrogen-induced intergranular cracking of tubular steels

    Institute of Scientific and Technical Information of China (English)

    乔利杰; 褚武扬; 于广华; 程以环

    1996-01-01

    Hydrogen could be enriched on grain boundaries by stress induction and other traps.The enriched hydrogen facilitated emission and movement of dislocations and lowered plastic work.Consequently,fracture occurred easily along grain boundary.A normalized threshold value of hydrogen-induced cracking (HIC) along grain boundary is given as (KIH/KIC)2=1-0.162×10-3 βHCc(H)GH/(2γs-γb-0.16×103∑β CiGi),where βH and βi are the enrichment factors of hydrogen and other elements on grain boundaries,respectively;Cc(H) is hydrogen concentration induced by stress;C,is the average concentration of an element in the steel;GH and Gi are factors of fracture work along grain boundary with hydrogen and other elements,and γs and γb are surface free energy and grain boundary energy of Fe.For tubular steel,the calculated KH/KIC is 0.23 while the determined value is 0.26.The theoretical threshold value is well consistent with the experimental one.

  14. Strength of Tubular Joints Made by Electromagnetic Compression at Quasistatic and Cyclic Loading

    OpenAIRE

    Barreiro, P.; Beerwald, C.; Homberg, W.; Kleiner, M.; Löhe, D.; Marré, M.; Schulze, V.

    2006-01-01

    Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for lightweight structures. The components are joined using pulsed magnetic fields which apply radial pressures of up to 200 MPa to tubular workpieces, causing a symmetric reduction of the diameter with typical strain rates of up to 10^4 sec^(-1). This process avoids any surface damage of the workpiece because there is no contact between component and forming tool. The strength o...

  15. Linear tubular switched reluctance motor for heart assistance circulatory: Analytical and finite element modeling

    OpenAIRE

    LLIBRE, Jean-François; Martinez, Nicolas; Nogarède, Bertrand; Leprince, Pascal

    2011-01-01

    A linear tubular switched reluctance motor is presented. This actuator is devoted to be used as a left ventricular assist device (LVAD). In order to avoid thrombosis, this actuator includes pump and valve functions. By using a St. Jude Medical mechanical valve inside the tubular mover, a pulsatile flow is created in the descending aorta. A linear model of a basic pattern of the actuator based on a reluctance network is developed. Then, a two dimensions finite element method analysis is per...

  16. Fiber beam model for fire response simulation of axially loaded concrete filled tubular columns

    OpenAIRE

    Ibáñez Usach, Carmen; Romero, Manuel L.; Hospitaler Pérez, Antonio

    2013-01-01

    This paper presents a fiber beam model for the fire response simulation of concrete filled tubular columns of circular section under concentric axial load. The model consists of two parallel components, one with a circular tubular steel section, and the other with a solid circular concrete section. The components interact with nonlinear longitudinal and transverse links at the end nodes. The element is formulated on a system without rigid body modes and accounts for large displacement geometr...

  17. FULL-FRONTAL COLLISION SIMULATIONS AND ANALYSES OF TUBULAR SPACE FRAME BODYWORK FOR SEDAN CAR

    Institute of Scientific and Technical Information of China (English)

    Huang Xiangdong; Chen Jinhua; Xie Yuecong; Giorgio Rizzoni

    2003-01-01

    Using CAE tools based on nonlinear finite element methods, full-frontal collision dynamic simulation and analysis of a sedan car body with 3D tubular loadbearing frame are tentatively carried out. Time histories of the main collisional parameters are presented, improvements of the frame are partially made according to simulation results. Collisional simulation of the tubular frame alone indicates that, such new type of bodywork for sedan car is of good potentialities to meet the collision safety regulations.

  18. Effect of cisplatin on renal haemodynamics and tubular function in the dog kidney

    DEFF Research Database (Denmark)

    Daugaard, G; Abildgaard, U; Holstein-Rathlou, N H;

    1987-01-01

    Administration of cisplatin (5 mg/kg) to dogs results in polyuric renal failure due initially to a proximal tubular functional impairment. 48-72 h after the cisplatin administration the depressed renal function can be attributed to impairment of proximal as well as distal tubular reabsorptive...... capacities associated with increased renal vascular resistance. The polyuria seems to be due to the impaired reabsorption rate in the distal nephron segments....

  19. Characterization of segregation in a tubular polymerization reactor by a new chemical method

    OpenAIRE

    Meyer, T; Renken, A.

    1990-01-01

    Micromixing in a tubular polymn. reactor is characterized by the mol. wt. of polystyrene obtained in the presence of a chain transfer agent. Monomer and the transfer agent are fed sep. into the reactor. For const. overall inlet concns., the mean mol. wt. produced is strongly dependent on mixing intensity. Expts. were carried out in a pilot plant loop tubular reactor of different configurations and monomer conversions ?80%. The degree of segregation as a function of energy dissipation and the ...

  20. Tubular cell phenotype in HIV-associated nephropathy: role of phospholipid lysophosphatidic acid.

    Science.gov (United States)

    Ayasolla, Kamesh R; Rai, Partab; Rahimipour, Shai; Hussain, Mohammad; Malhotra, Ashwani; Singhal, Pravin C

    2015-08-01

    Collapsing glomerulopathy and microcysts are characteristic histological features of HIV-associated nephropathy (HIVAN). We have previously reported the role of epithelial mesenchymal transition (EMT) in the development of glomerular and tubular cell phenotypes in HIVAN. Since persistent tubular cell activation of NFκB has been reported in HIVAN, we now hypothesize that HIV may be contributing to tubular cell phenotype via lysophosphatidic acid (LPA) mediated downstream signaling. Interestingly, LPA and its receptors have also been implicated in the tubular interstitial cell fibrosis (TIF) and cyst formation in autosomal dominant polycystic kidney disease (PKD). Primary human proximal tubular cells (HRPTCs) were transduced with either empty vector (EV/HRPTCs), HIV (HIV/HRPTCs) or treated with LPA (LPA/HRPTC). Immunoelectrophoresis of HIV/HRPTCs and LPA/HRPTCs displayed enhanced expression of pro-fibrotic markers: a) fibronectin (2.25 fold), b) connective tissue growth factor (CTGF; 4.8 fold), c) α-smooth muscle actin (α-SMA; 12 fold), and d) collagen I (5.7 fold). HIV enhanced tubular cell phosphorylation of ILK-1, FAK, PI3K, Akt, ERKs and P38 MAPK. HIV increased tubular cell transcriptional binding activity of NF-κB; whereas, a LPA biosynthesis inhibitor (AACOCF3), a DAG kinase inhibitor, a LPA receptor blocker (Ki16425), a NF-κB inhibitor (PDTC) and NFκB-siRNA not only displayed downregulation of a NFκB activity but also showed attenuated expression of profibrotic/EMT genes in HIV milieu. These findings suggest that LPA could be contributing to HIV-induced tubular cell phenotype via NFκB activation in HIVAN. PMID:26079546

  1. Fabrication of Coiled Tubular Heat Exchanger%绕管式换热器的制造

    Institute of Scientific and Technical Information of China (English)

    王自涛

    2015-01-01

    本文介绍了绕管换热器的技术特点及应用。从结构设计、技术等方面阐明了绕管换热器的设计制造的问题。%In is paper,the technical characteristics and application of coiled tubular heat exchanger were introduced. And the problem in design and manufacture of coiled tubular heat exchanger were clarified .

  2. Design and performance of tubular flat-plate solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, T.; Ikeda, D.; Kanagawa, H. [NTT Integrated Information & Energy Systems Labs., Tokyo (Japan)] [and others

    1996-12-31

    With the growing interest in conserving the environmental conditions, much attention is being paid to Solid Oxide Fuel Cell (SOFC), which has high energy-conversion efficiency. Many organizations have conducted studies on tubular and flat type SOFCs. Nippon Telegraph and Telephone Corporation (NTT) has studied a combined tubular flat-plate SOFC, and already presented the I-V characteristics of a single cell. Here, we report the construction of a stack of this SOFC cell and successful generation tests results.

  3. A new tubular graphene form of a tetrahedrally connected cellular structure.

    Science.gov (United States)

    Bi, Hui; Chen, I-Wei; Lin, Tianquan; Huang, Fuqiang

    2015-10-21

    3D architectures constructed from a tubular graphene network can withstand repeated >95% compression cycling without damage. Aided by intertubular covalent bonding, this material takes full advantage of the graphene tube's unique attributes, including complete pre- and post-buckling elasticity, outstanding electrical conductivity, and extraordinary physicochemical stability. A highly connected tubular graphene will thus be the ultimate, structurally robust, ultrastrong, ultralight material. PMID:26305918

  4. Human embryonic stem cells differentiate into functional renal proximal tubular-like cells.

    Science.gov (United States)

    Narayanan, Karthikeyan; Schumacher, Karl M; Tasnim, Farah; Kandasamy, Karthikeyan; Schumacher, Annegret; Ni, Ming; Gao, Shujun; Gopalan, Began; Zink, Daniele; Ying, Jackie Y

    2013-04-01

    Renal cells are used in basic research, disease models, tissue engineering, drug screening, and in vitro toxicology. In order to provide a reliable source of human renal cells, we developed a protocol for the differentiation of human embryonic stem cells into renal epithelial cells. The differentiated stem cells expressed markers characteristic of renal proximal tubular cells and their precursors, whereas markers of other renal cell types were not expressed or expressed at low levels. Marker expression patterns of these differentiated stem cells and in vitro cultivated primary human renal proximal tubular cells were comparable. The differentiated stem cells showed morphological and functional characteristics of renal proximal tubular cells, and generated tubular structures in vitro and in vivo. In addition, the differentiated stem cells contributed in organ cultures for the formation of simple epithelia in the kidney cortex. Bioreactor experiments showed that these cells retained their functional characteristics under conditions as applied in bioartificial kidneys. Thus, our results show that human embryonic stem cells can differentiate into renal proximal tubular-like cells. Our approach would provide a source for human renal proximal tubular cells that are not affected by problems associated with immortalized cell lines or primary cells.

  5. Prevalence of renal tubular dysfunction in beta thalassemia minor in shiraz

    Directory of Open Access Journals (Sweden)

    Ali Moradi Nakhodcheri

    2012-02-01

    Full Text Available  Background & objective: β-Thalassemia minor is an asymptomatic hereditary disease. The first study on the relation of renal tubular dysfunction and β-thalassemia minor was performed in 2002 but those studies seem inadequate.The main goal of this study is through evaluation of renal tubular function in 100 patients with thalassemia minor. Materials & Methods: 100 patients with β- thalassemia which confirmed by hemoglobin electrophoresis and CBC as well as RBC indices were studied.14 out of 100 cases exit because of Urinary Tract Infection, diabetes mellitus or hypertension.Complete chemistry profile was performed on serum and urine of all reminder 86 patients (46 female and 40 male. Patients classified into two groups: β-thalassemia minor with anemia and without anemia. Another control group include 50 healthy individuals also considered.Then data analyzed by proper statistical methods. Results: 20 out of 86 reminder cases e.g. 24% showed at least one index of renal tubular dysfunction.58% of patients was been anemic and 42% non anemic. The most prominent tubular dysfunction was seen in a 29 years old lady with glucosuria and without anemia. conclusion: β-Thalassemia minor is common in Iran specially in Fars province. This study revealed significant renal tubular dysfunction in patient with β-thalassemia minor. So it is necessary to check out thalassemic patients for renal function tests periodically. Key words: β-thalassemia, minor,renal tubular dysfunction

  6. Cadmium and cisplatin damage erythropoietin-producing proximal renal tubular cells

    Energy Technology Data Exchange (ETDEWEB)

    Horiguchi, Hyogo; Oguma, Etsuko; Kayama, Fujio [Jichi Medical School, Division of Environmental Medicine, Center for Community Medicine, Tochigi (Japan); Core Research for Evolutional Science and Technology, Japan Science Technology Corporation (CREST-JST), Saitama (Japan)

    2006-10-15

    The concomitant manifestations of proximal renal tubular dysfunction and anemia with erythropoietin (Epo) deficiency observed in chronic cadmium (Cd) intoxication, such as Itai-itai disease, suggest a close local correlation between the Cd-targeted tubular cells and Epo-producing cells in the kidney. Therefore, we investigated the local relationship between hypoxia-induced Epo production and renal tubular injury in rats injected with Cd at 2 mg/kg twice a week for 8 months. Anemia due to insufficient production of Epo was observed in Cd-intoxicated rats. In situ hybridization detected Epo mRNA expression in the proximal renal tubular cells of hypoxic rats without Cd intoxication, and the Cd-intoxicated rats showed atrophy of Epo-expressing renal tubules and replacement of them with fibrotic tissue. A single dose of cisplatin at 8 mg/kg, which can induce clinical manifestations similar to those of Cd including renal tubular damage along with Epo-deficient anemia, resulted in Epo-expressing renal tubule destruction on day 4. These data indicate that Cd and cisplatin would induce anemia through the direct injury of the proximal renal tubular cells that are responsible for Epo production. (orig.)

  7. Ground Vibration Isolation of Multiple Scattering by Using Rows of Tubular Piles as Barriers

    Directory of Open Access Journals (Sweden)

    Miao-miao Sun

    2014-01-01

    Full Text Available A new formal solution for the multiple scattering of plane harmonic waves by a group of arbitrary configuration tubular piles in an elastic total space is derived. Each order of scattering satisfies prescribed boundary conditions at the interface of tubular piles, which is delivered as the sum of incident and scattering waves. The first order performs the scattering wave by each scattered pile and the subsequent orders resulted from the excitation of each pile of first order of scattering from the remaining tubular piles. Advanced scattering orders can be regarded as the same manners. Several series of scattering coefficients are figured out with the aids of addition theorem so that the exact steady-state solution for the scattered displacement and stress is obtained. Particularly, when internal diameter of tubular piles tends to be infinitely small, it degenerates to a solid pile problem. By imposing the normalized displacement amplitudes and transmissibility indices, the influences of specific parameters such as scattering orders, internal and external diameter ratio of piles, pile material rigidity, position and distances between tubular pile and pile rows, and pile numbers are discussed. Certain recommended conclusions have been drawn as the guidelines of practical engineering design for discontinuous barrier of tubular piles.

  8. Perfluorooctanesulfonate Mediates Renal Tubular Cell Apoptosis through PPARgamma Inactivation.

    Directory of Open Access Journals (Sweden)

    Li-Li Wen

    Full Text Available Perfluorinated chemicals (PFCs are ubiquitously distributed in the environments including stainless pan-coating, raincoat, fire extinguisher, and semiconductor products. The PPAR family has been shown to contribute to the toxic effects of PFCs in thymus, immune and excretory systems. Herein, we demonstrated that perfluorooctanesulfonate (PFOS caused cell apoptosis through increasing ratio of Bcl-xS/xL, cytosolic cytochrome C, and caspase 3 activation in renal tubular cells (RTCs. In addition, PFOS increased transcription of inflammatory cytokines (i.e., TNFα, ICAM1, and MCP1 by NFκB activation. Conversely, PFOS reduced the mRNA levels of antioxidative enzymes, such as glutathione peroxidase, catalase, and superoxide dismutase, as a result of reduced PPARγ transactivational activity by using reporter and chromatin immuoprecipitation (ChIP assays. PFOS reduced the protein interaction between PPARγ and PPARγ coactivator-1 alpha (PGC1α by PPARγ deacetylation through Sirt1 upregulation, of which the binding of PPARγ and PGC1α to a peroxisome proliferator response element (PPRE in the promoter regions of these antioxidative enzymes was alleviated in the ChIP assay. Furthermore, Sirt1 also deacetylated p53 and then increased the binding of p53 to Bax, resulting in increased cytosolic cytochrome C. The effect of PPARγ inactivation by PFOS was validated using the PPARγ antagonist GW9662, whereas the adverse effects of PFOS were prevented by PPARγ overexpression and activators, rosiglitozone and L-carnitine, in RTCs. The in vitro finding of protective effect of L-carnitine was substantiated in vivo using Balb/c mice model subjected to PFOS challenge. Altogether, we provide in vivo and in vitro evidence for the protective mechanism of L-carnitine in eliminating PFOS-mediated renal injury, at least partially, through PPARγ activation.

  9. Shear Stress-Induced Alteration of Epithelial Organization in Human Renal Tubular Cells.

    Directory of Open Access Journals (Sweden)

    Damien Maggiorani

    Full Text Available Tubular epithelial cells in the kidney are continuously exposed to urinary fluid shear stress (FSS generated by urine movement and recent in vitro studies suggest that changes of FSS could contribute to kidney injury. However it is unclear whether FSS alters the epithelial characteristics of the renal tubule. Here, we evaluated in vitro and in vivo the influence of FSS on epithelial characteristics of renal proximal tubular cells taking the organization of junctional complexes and the presence of the primary cilium as markers of epithelial phenotype. Human tubular cells (HK-2 were subjected to FSS (0.5 Pa for 48 h. Control cells were maintained under static conditions. Markers of tight junctions (Claudin-2, ZO-1, Par polarity complex (Pard6, adherens junctions (E-Cadherin, β-Catenin and the primary cilium (α-acetylated Tubulin were analysed by quantitative PCR, Western blot or immunocytochemistry. In response to FSS, Claudin-2 disappeared and ZO-1 displayed punctuated and discontinuous staining in the plasma membrane. Expression of Pard6 was also decreased. Moreover, E-Cadherin abundance was decreased, while its major repressors Snail1 and Snail2 were overexpressed, and β-Catenin staining was disrupted along the cell periphery. Finally, FSS subjected-cells exhibited disappeared primary cilium. Results were confirmed in vivo in a uninephrectomy (8 months mouse model where increased FSS induced by adaptive hyperfiltration in remnant kidney was accompanied by both decreased epithelial gene expression including ZO-1, E-cadherin and β-Catenin and disappearance of tubular cilia. In conclusion, these results show that proximal tubular cells lose an important number of their epithelial characteristics after long term exposure to FSS both in vitro and in vivo. Thus, the changes in urinary FSS associated with nephropathies should be considered as potential insults for tubular cells leading to disorganization of the tubular epithelium.

  10. Experimental and numerical investigation of expandable tubular structural integrity for well applications

    Directory of Open Access Journals (Sweden)

    T. Pervez

    2010-07-01

    Full Text Available Purpose: The ever-increasing energy demand has forced researchers to search for new and cheaper solutions for oil and gas production. The recent development of solid expandable tubulars (SETs has resulted in design of slim oil and gas wells. The large plastic deformation experienced by the tubular under down-hole environment may result in premature and unexpected failures. The objective of this research is to investigate the structural integrity of SET for well applications to avoid such failures.Design/methodology/approach: In order to achieve the objectives, simulation work was carried out using finite element method and experimental tests were conducted on full size tubular for validation of numerical results.Findings: The required drawing force for expansion under different expansion ratios, surplus deformation, variations in tubular thickness and length were estimated numerically and experimentally. The differences in values using two approaches vary from 5% to 12%. Tubular wall thickness decreases as the mandrel angle, expansion ratio, and friction coefficient increase.Research limitations/implications: The issue of maximum expansion a tubular can be subjected to needs to be further investigated. Furthermore, the pre and post-expansion material properties need immediate attention of researchers to fulfil the dream of low-cost expandable solution.Practical implications: In recent years, solid expandable tubular technology has already made significant inroads in replacing conventional telescopic oil wells. It allows design and realization of slim wells, accessing difficult and ultra-deep reservoirs, well remediation, zonal isolation, drilling of directional and horizontal wells, etc.Originality/value: SET is an emerging technology for oil and gas industry. The current findings are very valuable for researchers and well engineers to design slim wells and enhance the productivity of older wells.

  11. Genome-wide profiling to analyze the effects of FXR activation on mouse renal proximal tubular cells

    OpenAIRE

    Gui, Ting; Gai, Zhibo

    2015-01-01

    To assess the effect of farnesoid X receptor (FXR), a bile acid nuclear receptor, on renal proximal tubular cells, primary cultured mouse kidney proximal tubular cells were treated with GW4064 (a FXR agonist) or DMSO (as controls) overnight. Analysis of gene expression in the proximal tubular cells by whole genome microarrays indicated that FXR activation induced genes involved in fatty acid degradation and oxidation reduction. Among them, genes involved in glutathione metabolism were mostly ...

  12. Osteomalacia complicating renal tubular acidosis in association with Sjogren's syndrome.

    Science.gov (United States)

    El Ati, Zohra; Fatma, Lilia Ben; Boulahya, Ghada; Rais, Lamia; Krid, Madiha; Smaoui, Wided; Maiz, Hedi Ben; Beji, Soumaya; Zouaghi, Karim; Moussa, Fatma Ben

    2014-09-01

    Renal involvement in Sjogren's syndrome (SS) is not uncommon and may precede other complaints. Tubulointerstitial nephritis is the most common renal disease in SS and may lead to renal tubular acidosis (RTA), which in turn may cause osteomalacia. Nevertheless, osteomalacia rarely occurs as the first manifestation of a renal tubule disorder due to SS. We herewith describe a 43-year-old woman who was admitted to our hospital for weakness, lumbago and inability to walk. X-ray of the long bones showed extensive demineralization of the bones. Laboratory investigations revealed chronic kidney disease with serum creatinine of 2.3 mg/dL and creatinine clearance of 40 mL/min, hypokalemia (3.2 mmol/L), hypophosphatemia (0.4 mmol/L), hypocalcemia (2.14 mmol/L) and hyperchloremic metabolic acidosis (chlorine: 114 mmol/L; alkaline reserve: 14 mmol/L). The serum alkaline phosphatase levels were elevated. The serum levels of 25-hydroxyvitamin D and 1,25-dihydroxy vitamin D were low and borderline low, respectively, and the parathyroid hormone level was 70 pg/L. Urinalysis showed inappropriate alkaline urine (urinary PH: 7), glycosuria with normal blood glucose, phosphaturia and uricosuria. These values indicated the presence of both distal and proximal RTA. Our patient reported dryness of the mouth and eyes and Schirmer's test showed xerophthalmia. An accessory salivary gland biopsy showed changes corresponding to stage IV of Chisholm and Masson score. Kidney biopsy showed diffuse and severe tubulo-interstitial nephritis with dense lymphoplasmocyte infiltrates. Sicca syndrome and renal interstitial infiltrates indicated SS as the underlying cause of the RTA and osteomalacia. The patient received alkalinization, vitamin D (Sterogyl ®), calcium supplements and steroids in an initial dose of 1 mg/kg/day, tapered to 10 mg daily. The prognosis was favorable and the serum creatinine level was 1.7 mg/dL, calcium was 2.2 mmol/L and serum phosphate was 0.9 mmol/L. PMID:25193912

  13. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1.

    Science.gov (United States)

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro; Nadaj-Pakleza, Aleksandra; Vialle, Marc; Fattori, Fabiana; Vissing, John; Ricci, Enzo; Bertini, Enrico

    2015-11-01

    Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients especially among other forms of tubular aggregate myopathy. PMID:26255678

  14. Medullary nephrocalcinosis, distal renal tubular acidosis and polycythaemia in a patient with nephrotic syndrome

    Directory of Open Access Journals (Sweden)

    Karunarathne Suneth

    2012-07-01

    Full Text Available Abstract Background Medullary nephrocalcinosis and distal renal tubular acidosis are closely associated and each can lead to the other. These clinical entities are rare in patients with nephrotic syndrome and polycythaemia is an unusual finding in such patients. We describe the presence of medullary nephrocalcinosis, distal renal tubular acidosis and polycythaemia in a patient with nephrotic syndrome due to minimal change disease. Proposed mechanisms of polycythaemia in patients with nephrotic syndrome and distal renal tubular acidosis include, increased erythropoietin production and secretion of interleukin 8 which in turn stimulate erythropoiesis. Case presentation A 22 year old Sri Lankan Sinhala male with nephrotic syndrome due to minimal change disease was investigated for incidentally detected polycythaemia. Investigations revealed the presence of renal tubular acidosis type I and medullary nephrocalcinosis. Despite extensive investigation, a definite cause for polycythaemia was not found in this patient. Treatment with potassium and bicarbonate supplementation with potassium citrate led to correction of acidosis thereby avoiding the progression of nephrocalcinosis and harmful effects of chronic acidosis. Conclusion The constellation of clinical and biochemical findings in this patient is unique but the pathogenesis of erythrocytosis is not clearly explained. The proposed mechanisms for erythrocytosis in other patients with proteinuria include increased erythropoietin secretion due to renal hypoxia and increased secretion of interleukin 8 from the kidney. This case illustrates that there may exist hitherto unknown connections between tubular and glomerular dysfunction in patients with nephrotic syndrome.

  15. Losartan attenuates renal interstitial fibrosis and tubular cell apoptosis in a rat model of obstructive nephropathy.

    Science.gov (United States)

    He, Ping; Li, Detian; Zhang, Beiru

    2014-08-01

    Ureteral obstruction leads to renal injury and progresses to irreversible renal fibrosis, with tubular cell atrophy and apoptosis. There is conflicting evidence concerning whether losartan (an angiotensin II type I receptor antagonist) mitigates renal interstitial fibrosis and renal tubular epithelial cell apoptosis following unilateral ureteral obstruction (UUO) in animal models. The aim of this study was to investigate the effect and mechanism of losartan on renal tubular cell apoptosis and renal fibrosis in a rat model of UUO. The rats were subjected to UUO by ureteral ligation and were treated with dimethyl sulfoxide (control) or losartan. The controls underwent sham surgery. The renal tissues were collected 3, 5, 7 and 14 days after surgery for measurement of various indicators of renal fibrosis. UUO increased the expression levels of α‑smooth muscle actin and collagen I, and the extent of renal tubular fibrosis and apoptosis in a time‑dependent manner. Losartan treatment partially attenuated these responses. Progression of renal interstitial fibrosis was accompanied by phosphorylation of signal transducer and activator of transcription 3 (STAT3) and altered the expression levels of two apoptosis‑related proteins (Bax and Bcl2). Losartan treatment also partially attenuated these responses. The results indicated that losartan attenuated renal fibrosis and renal tubular cell apoptosis in a rat model of UUO. This effect appeared to be mediated by partial blockage of STAT3 phosphorylation.

  16. CD36 mediates proximal tubular binding and uptake of albumin and is upregulated in proteinuric nephropathies.

    Science.gov (United States)

    Baines, Richard J; Chana, Ravinder S; Hall, Matthew; Febbraio, Maria; Kennedy, David; Brunskill, Nigel J

    2012-10-01

    Dysregulation of renal tubular protein handling in proteinuria contributes to the development of chronic kidney disease. We investigated the role of CD36 as a novel candidate mediator of albumin binding and endocytosis in the kidney proximal tubule using both in vitro and in vivo approaches, and in nephrotic patient renal biopsy samples. In CD36-transfected opossum kidney proximal tubular cells, both binding and uptake of albumin were substantially enhanced. A specific CD36 inhibitor abrogated this effect, but receptor-associated protein, which blocks megalin-mediated endocytosis of albumin, did not. Mouse proximal tubular cells expressed CD36 and this was absent in CD36 null animals, whereas expression of megalin was equal in these animals. Compared with wild-type mice, CD36 null mice demonstrated a significantly increased urinary protein-to-creatinine ratio and albumin-to-creatinine ratio. Proximal tubular cells expressed increased CD36 when exposed to elevated albumin concentrations in culture medium. Expression of CD36 was studied in renal biopsy tissue obtained from adult patients with heavy proteinuria due to minimal change disease, membranous nephropathy, or focal segmental glomerulosclerosis. Proximal tubular CD36 expression was markedly increased in proteinuric individuals. We conclude that CD36 is a novel mediator influencing binding and uptake of albumin in the proximal tubule that is upregulated in proteinuric renal diseases. CD36 may represent a potential therapeutic target in proteinuric nephropathy. PMID:22791331

  17. p-Cresol mediates autophagic cell death in renal proximal tubular cells.

    Science.gov (United States)

    Lin, Hsin-Hung; Huang, Chiu-Ching; Lin, Tze-Yi; Lin, Ching-Yuang

    2015-04-01

    Higher serum level of p-cresol (PC) in chronic kidney disease (CKD) patients has been linked with CKD progression. The toxic effect of PC on diverse cells has been reported by prior studies, except for renal tubular cells. Both autophagy and apoptosis contribute to renal tubular cell death, yet evidence of its response to PC is limited and their crosstalk is still unclear. Autophagy is an important cellular process involved in toxin-induced cell death. Renal tubular cell death in tubular injury is thought to be one of the key events causing the progression of CKD. Thus, we treated rat (NRK-52E) and human (HRPTEC) renal proximal tubular cells (RPTC) with PC and found the cell proliferation was significantly decreased. Cell apoptosis was significantly increased and accompanied with the activation of autophagy as evidenced by increases in LC3-II, beclin 1 and Atg 4. We also found an increase of p62 by c-Jun activation. p62 accumulation could mediate the activation of caspase 8-dependent cell apoptosis. Conversely, knockdown of p62 by siRNA of p62 had the opposite effect by arresting LC3-II accumulation and promoting increasing cell viability. We conclude that PC triggered autophagic RPTC death via JNK-mediated p62 accumulation and then activated caspase 8-dependent cell death pathway. PC can be considered as one of the key events causing progression of CKD, which might affect drug disposition in CKD cases. PMID:25668154

  18. A new minimally invasive tubular brain retractor system for surgery of deep intracerebral hematoma

    Directory of Open Access Journals (Sweden)

    Yad R Yadav

    2011-01-01

    Full Text Available Access to deep-seated brain lesions with traditional fixed and rigid brain retractors can be difficult without causing significant trauma to the surrounding brain. Tubular retractors offer an advantage of low retracting pressure. We developed a new inexpensive and simple tubular retractor which requires very small cortisectomy. The new tubular retractor was made up of silicone with inner diameter of 15, 18 and 23 mm and outer diameter of 17, 20 and 25 mm, respectively. This tube (1 mm thick was cut in longitudinal direction. It was folded to make a small-diameter tube so that it could be introduced through a small cortisectomy. Margins of cortisectomy were gently and slowly retracted by Killian nasal speculum. Folded retractor, held by tissue forceps, was introduced inside the opened Killian nasal speculum. Tissue forceps and nasal speculum were removed leaving tubular retractor in place, which comes back to its normal tubular configuration after release. Surgery was performed using rigid Karl Storz 0° telescope (30 cm long and 4 mm in diameter or microscope. Near-total removals of intracerebral hematomas, 37 hypertensive and 3 traumatic, was done using this retractor without any complication.

  19. Inverse Approach to Evaluate the Tubular Material Parameters Using the Bulging Test

    Directory of Open Access Journals (Sweden)

    Yulong Ge

    2015-01-01

    Full Text Available Tubular material parameters are required for both part manufactory process planning and finite element simulations. The bulging test is one of the most credible ways to detect the property parameters for tubular material. The inverse approach provides more effective access to the accurate material evaluation than with direct identifications. In this paper, a newly designed set of bulging test tools is introduced. An inverse procedure is adopted to determine the tubular material properties in Krupkowski-Swift constitutive model of material deformation using a hybrid algorithm that combines the differential evolution and Levenberg-Marquardt algorithms. The constitutive model’s parameters obtained from the conventional and inverse methods are compared, and this comparison shows that the inverse approach is able to offer more information with higher reliability and can simplify the test equipment.

  20. Inspection system for welded tubular joint based on ultrasonic phased array

    Institute of Scientific and Technical Information of China (English)

    Hao Guangping; Deng Zongquan; Shan Baohua; Yu Weizhen; Li Lifang

    2010-01-01

    A manual inspection of large-diameter tubular joints is difficult. As a result a scanner with three degrees of freedom (DOFs) was developed based on the scanning principle of ultrasonic phased array. The weld tracing is realized by a 2D0F motion of scanner. The pose of ultrasonic probe is controlled by the third one. The control strategy is put forward based on a programmable multi-axis controller. Four kinds of scanning modes can be implemented simultaneously employing this ultrasonic inspection system. Experiments on reference blocks of tubular joints reveal that the automatic ultrasonic phased array inspection system has the same inspection accuracy as a manual ultrasonic inspection. This system is superior to the manual ultrasonic system in terms of reliability and repeatability. The artificial defects of weld at tubular joint can be detected accurately with the presented inspection system.

  1. Ioxaglate-induced light and electron microscopic alterations in the renal proximal tubular epithelium of rats.

    Science.gov (United States)

    Battenfeld, R; Khater A el-R; Drommer, W; Guenzel, P; Kaup, F J

    1991-01-01

    Vacuolization of the proximal tubular epithelial cells was produced in rats by the intravenous administration of the radiographic contrast medium ioxaglate at high multiples of the human diagnostic dose. Samples of the renal cortex and outer zone of the medulla were examined by light and electron microscopy. We observed enlargement, confluence, and migration of vacuoles containing pleomorphic dense material and distinct inclusion bodies. With time, vacuolization disappeared, though single vacuoles partly engaged in extruding their contents into the tubular lumen were still visible. We concluded that radiographic contrast medium at high dose levels can produce a reversible disturbance in the transport vesicular system of the proximal tubular epithelial cells without affecting the specific cell organelles. PMID:2022451

  2. Micro-Drilling of Polymer Tubular Ultramicroelectrode Arrays for Electrochemical Sensors

    Directory of Open Access Journals (Sweden)

    Niels B. Larsen

    2013-05-01

    Full Text Available We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene (PEDOT, a conductive polymer. Arrays of Ø 100 µm tubular electrodes each having a height of 0.37 ± 0.06 µm were reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals were in agreement with results from finite element modelling of the system. The tubular PEDOT ultramicroelectrode arrays were modified by prussian blue to enable the detection of hydrogen peroxide. A linear sensor response was demonstrated for hydrogen peroxide concentrations from 0.1 mM to 1 mM.

  3. Micro-drilling of polymer tubular ultramicroelectrode arrays for electrochemical sensors.

    Science.gov (United States)

    Kafka, Jan; Skaarup, Steen; Geschke, Oliver; Larsen, Niels B

    2013-05-14

    We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer. Arrays of Ø 100 µm tubular electrodes each having a height of 0.37 ± 0.06 µm were reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals were in agreement with results from finite element modelling of the system. The tubular PEDOT ultramicroelectrode arrays were modified by prussian blue to enable the detection of hydrogen peroxide. A linear sensor response was demonstrated for hydrogen peroxide concentrations from 0.1 mM to 1 mM.

  4. Population analysis of the cingulum bundle using the tubular surface model for schizophrenia detection

    Science.gov (United States)

    Mohan, Vandana; Sundaramoorthi, Ganesh; Kubicki, Marek; Terry, Douglas; Tannenbaum, Allen

    2010-03-01

    We propose a novel framework for population analysis of DW-MRI data using the Tubular Surface Model. We focus on the Cingulum Bundle (CB) - a major tract for the Limbic System and the main connection of the Cingulate Gyrus, which has been associated with several aspects of Schizophrenia symptomatology. The Tubular Surface Model represents a tubular surface as a center-line with an associated radius function. It provides a natural way to sample statistics along the length of the fiber bundle and reduces the registration of fiber bundle surfaces to that of 4D curves. We apply our framework to a population of 20 subjects (10 normal, 10 schizophrenic) and obtain excellent results with neural network based classification (90% sensitivity, 95% specificity) as well as unsupervised clustering (k-means). Further, we apply statistical analysis to the feature data and characterize the discrimination ability of local regions of the CB, as a step towards localizing CB regions most relevant to Schizophrenia.

  5. Species diversity regarding the presence of proximal tubular progenitor cells of the kidney

    Directory of Open Access Journals (Sweden)

    J. Hansson

    2016-02-01

    Full Text Available The cellular source for tubular regeneration following kidney injury is a matter of dispute, with reports suggesting a stem or progenitor cells as the regeneration source while linage tracing studies in mice seemingly favor the classical theory, where regeneration is performed by randomly surviving cells. We, and others have previously described a scattered cell population localized to the tubules of human kidney, which increases in number following injury. Here we have characterized the species distribution of these proximal tubular progenitor cells (PTPCs in kidney tissue from chimpanzee, pig, rat and mouse using a set of human PTPC markers. We detected PTPCs in chimpanzee and pig kidneys, but not in mouse tissue. Also, subjecting mice to the unilateral urethral obstruction model, caused clear signs of tubular injury, but failed to induce the PTPC phenotype in renal tubules.

  6. Produção e degradação in vitro de estruturas tubulares de celulose bacteriana

    Directory of Open Access Journals (Sweden)

    Vanessa A. Oliveira

    2013-01-01

    Full Text Available A necessidade de novos recursos em cardiologia tem direcionado a Engenharia de Tecidos ao desenvolvimento de vasos sanguíneos artificiais que atendam aos requisitos do organismo. Neste trabalho, estruturas tubulares de celulose bacteriana (CB foram produzidas e sua degradação in vitro foi avaliada. Através de microscopia eletrônica de varredura constatou-se que não houve alterações significativas na microestrutura e morfologia das fibras de CB após ensaios de degradação. Os ensaios de degradação em soluções fisiológicas PBS e salina revelaram uma degradação substancialmente baixa após 20 semanas. A baixa velocidade de degradação dos vasos é de grande importância, visto que o processo para a formação de novos vasos (angiogênese demanda tempo.

  7. Interferon-γ Reduces the Proliferation of Primed Human Renal Tubular Cells

    Directory of Open Access Journals (Sweden)

    Omar García-Sánchez

    2014-01-01

    Full Text Available Background/Aims: Chronic kidney disease (CKD is a progressive deterioration of the kidney function, which may eventually lead to renal failure and the need for dialysis or kidney transplant. Whether initiated in the glomeruli or the tubuli, CKD is characterized by progressive nephron loss, for which the process of tubular deletion is of key importance. Tubular deletion results from tubular epithelial cell death and defective repair, leading to scarring of the renal parenchyma. Several cytokines and signaling pathways, including transforming growth factor-β (TGF-β and the Fas pathway, have been shown to participate in vivo in tubular cell death. However, there is some controversy about their mode of action, since a direct effect on normal tubular cells has not been demonstrated. We hypothesized that epithelial cells would require specific priming to become sensitive to TGF-β or Fas stimulation and that this priming would be brought about by specific mediators found in the pathological scenario. Methods: Herein we studied whether the combined effect of several stimuli known to take part in CKD progression, namely TGF-β, tumor necrosis factor-α, interferon-γ (IFN-γ, and Fas stimulation, on primed resistant human tubular cells caused cell death or reduced proliferation. Results: We demonstrate that these cytokines have no synergistic effect on the proliferation or viability of human kidney (HK2 cells. We also demonstrate that IFN-γ, but not the other stimuli, reduces the proliferation of cycloheximide-primed HK2 cells without affecting their viability. Conclusion: Our results point at a potentially important role of IFN-γ in defective repair, leading to nephron loss during CKD.

  8. Ceria catalyst for inert-substrate-supported tubular solid oxide fuel cells running on methane fuel

    Science.gov (United States)

    Zhao, Kai; Kim, Bok-Hee; Du, Yanhai; Xu, Qing; Ahn, Byung-Guk

    2016-05-01

    A ceria catalyst is applied to an inert-substrate supported tubular single cell for direct operation on methane fuel. The tubular single cell comprises a porous yttria-stabilized zirconia (YSZ) supporter, a Ni-Ce0.8Sm0.2O1.9 anode, a YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte, and a La0.6Sr0.4Co0.2Fe0.8O3-δ cathode. The ceria catalyst is incorporated into the porous YSZ supporter layer by a cerium nitrate impregnation. The effects of ceria on the microstructure and electrochemical performance of the tubular single cell are investigated with respect to the number of impregnations. The optimum number of impregnations is determined to be four based on the maximum power density and polarization property of the tubular single cell in hydrogen and methane fuels. At 700 °C, the tubular single cell shows similar maximum power densities of ∼260 mW cm-2 in hydrogen and methane fuels, respectively. Moreover, the ceria catalyst significantly improves the performance stability of the cell running on methane fuel. At a current density of 350 mA cm-2, the single cell shows a low degradation rate of 2.5 mV h-1 during the 13 h test in methane fuel. These results suggest the feasibility of applying the ceria catalyst to the inert-substrate supported tubular single cell for direct operation on methane fuel.

  9. A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

    Science.gov (United States)

    Sarban, R.; Jones, R. W.; Mace, B. R.; Rustighi, E.

    2011-11-01

    This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower TM, is produced in thin sheets of 80 μm thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental measurements from 3 actuators. The dynamic characteristics of three tubular actuators fabricated from the same batch of manufactured DE material are presented and compared to: (a) provide insight into the ability of the fabrication process to produce actuators with similar characteristics and (b) highlight the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated 'ground vibration'. An adaptive feedforward control approach is used to achieve this. The tubular actuator is shown to provide excellent isolation against harmonic vibratory disturbances with attenuation of the resulting 5 and 10 Hz harmonics being 66 and 23 dB, respectively. AVI against a narrow band vibratory disturbance with frequency content 2-8 Hz, produced an attenuation of 20 dB across the frequency band.

  10. Spray Deposition Behavior and Numerical Simulation of Growth of Tubular Preform in Spray Forming Process

    Institute of Scientific and Technical Information of China (English)

    XIANG Jin-zong; ZHANG Yin; FAN Wen-jun; WANG Ping; HE You-duo

    2012-01-01

    Analysis on the deposition behavior of spray on deposition surface was made and an optimization method for the movement parameters (u, ω) of substrate was obtained. Simultaneously, a mathematical model of growth of tubular preform, specifically aimed at the kind of atomizer that is fixed and with a tilt angle was established. By in- tegrating the optimization method and the mathematical model, the growth process and shape of preform were simu- lated. The results show that the tilt angle of atomizer plays an important role on the dimensions and shapes of tubular preforms and it can provide a guidance for the development of spray forming equipment.

  11. A Thermal Analysis of Characteristic Parameters in the Electrode—Region for Tubular Plasma Generators

    Institute of Scientific and Technical Information of China (English)

    LinLie; WuChengkang

    1995-01-01

    A thermal analysis of characteristic parameters in the electrode-region for tubular plasma generators is developed.Results of calculation on tempeature of electrodes,evaporation rate and erosion rate for different electrode materials are presented as a function of arc current,pressure of arc chamber,width of arc root and velocity of water coolant.Some experimental data on electrode erosion in a tubular plasma generator is given.The effects of operating parameters on erosion rate are discussed in detail.

  12. Decolorization and partial mineralization of a polyazo dye by Bacillus firmus immobilized within tubular polymeric gel

    OpenAIRE

    Ogugbue, Chimezie Jason; Morad, Norhashimah; Sawidis, Thomas; Oranusi, Nathaniel A.

    2011-01-01

    The degradation of C.I. Direct red 80, a polyazo dye, was investigated using Bacillus firmus immobilized by entrapment in tubular polymeric gel. This bacterial strain was able to completely decolorize 50 mg/L of C.I. Direct red 80 under anoxic conditions within 12 h and also degrade the reaction intermediates (aromatic amines) during the subsequent 12 h under aerobic conditions. The tubular gel harboring the immobilized cells consisted of anoxic and aerobic regions integrated in a single unit...

  13. Mesenchymal stem cells modulate albumin-induced renal tubular inflammation and fibrosis.

    Directory of Open Access Journals (Sweden)

    Hao Jia Wu

    Full Text Available Bone marrow-derived mesenchymal stem cells (BM-MSCs have recently shown promise as a therapeutic tool in various types of chronic kidney disease (CKD models. However, the mechanism of action is incompletely understood. As renal prognosis in CKD is largely determined by the degree of renal tubular injury that correlates with residual proteinuria, we hypothesized that BM-MSCs may exert modulatory effects on renal tubular inflammation and epithelial-to-mesenchymal transition (EMT under a protein-overloaded milieu. Using a co-culture model of human proximal tubular epithelial cells (PTECs and BM-MSCs, we showed that concomitant stimulation of BM-MSCs by albumin excess was a prerequisite for them to attenuate albumin-induced IL-6, IL-8, TNF-α, CCL-2, CCL-5 overexpression in PTECs, which was partly mediated via deactivation of tubular NF-κB signaling. In addition, albumin induced tubular EMT, as shown by E-cadherin loss and α-SMA, FN and collagen IV overexpression, was also prevented by BM-MSC co-culture. Albumin-overloaded BM-MSCs per se retained their tri-lineage differentiation capacity and overexpressed hepatocyte growth factor (HGF and TNFα-stimulating gene (TSG-6 via P38 and NF-κB signaling. Albumin-induced tubular CCL-2, CCL-5 and TNF-α overexpression were suppressed by recombinant HGF treatment, while the upregulation of α-SMA, FN and collagen IV was attenuated by recombinant TSG-6. Neutralizing HGF and TSG-6 abolished the anti-inflammatory and anti-EMT effects of BM-MSC co-culture in albumin-induced PTECs, respectively. In vivo, albumin-overloaded mice treated with mouse BM-MSCs had markedly reduced BUN, tubular CCL-2 and CCL-5 expression, α-SMA and collagen IV accumulation independent of changes in proteinuria. These data suggest anti-inflammatory and anti-fibrotic roles of BM-MSCs on renal tubular cells under a protein overloaded condition, probably mediated via the paracrine action of HGF and TSG-6.

  14. Mesenchymal Stem Cells Modulate Albumin-Induced Renal Tubular Inflammation and Fibrosis

    Science.gov (United States)

    Wu, Hao Jia; Yiu, Wai Han; Li, Rui Xi; Wong, Dickson W. L.; Leung, Joseph C. K.; Chan, Loretta Y. Y.; Zhang, Yuelin; Lian, Qizhou; Lin, Miao; Tse, Hung Fat; Lai, Kar Neng; Tang, Sydney C. W.

    2014-01-01

    Bone marrow-derived mesenchymal stem cells (BM-MSCs) have recently shown promise as a therapeutic tool in various types of chronic kidney disease (CKD) models. However, the mechanism of action is incompletely understood. As renal prognosis in CKD is largely determined by the degree of renal tubular injury that correlates with residual proteinuria, we hypothesized that BM-MSCs may exert modulatory effects on renal tubular inflammation and epithelial-to-mesenchymal transition (EMT) under a protein-overloaded milieu. Using a co-culture model of human proximal tubular epithelial cells (PTECs) and BM-MSCs, we showed that concomitant stimulation of BM-MSCs by albumin excess was a prerequisite for them to attenuate albumin-induced IL-6, IL-8, TNF-α, CCL-2, CCL-5 overexpression in PTECs, which was partly mediated via deactivation of tubular NF-κB signaling. In addition, albumin induced tubular EMT, as shown by E-cadherin loss and α-SMA, FN and collagen IV overexpression, was also prevented by BM-MSC co-culture. Albumin-overloaded BM-MSCs per se retained their tri-lineage differentiation capacity and overexpressed hepatocyte growth factor (HGF) and TNFα-stimulating gene (TSG)-6 via P38 and NF-κB signaling. Albumin-induced tubular CCL-2, CCL-5 and TNF-α overexpression were suppressed by recombinant HGF treatment, while the upregulation of α-SMA, FN and collagen IV was attenuated by recombinant TSG-6. Neutralizing HGF and TSG-6 abolished the anti-inflammatory and anti-EMT effects of BM-MSC co-culture in albumin-induced PTECs, respectively. In vivo, albumin-overloaded mice treated with mouse BM-MSCs had markedly reduced BUN, tubular CCL-2 and CCL-5 expression, α-SMA and collagen IV accumulation independent of changes in proteinuria. These data suggest anti-inflammatory and anti-fibrotic roles of BM-MSCs on renal tubular cells under a protein overloaded condition, probably mediated via the paracrine action of HGF and TSG-6. PMID:24646687

  15. Non-linear finite element analysis of tubular X joint with selected geometry

    OpenAIRE

    Ghanem Nia, Nima

    2012-01-01

    Tubular Joints” play a very important and quite vital role in most of the marine structures; we can see maybe hundreds of them in every even simple jacket or steel platforms. It is obvious that having full control about capacity and strength of tubular joints would be very worthy to have good knowledge about total performance of the structure. During recent years the application of the finite element (FE) method has become very popular in the analyses of different types of welded circular tu...

  16. In-Situ TEM-STM Observations of SWCNT Ropes/Tubular Transformations

    Science.gov (United States)

    Sola, F.; Lebron-Colon, M.; Ferreira, P. J.; Fonseca, L. F.; Meador, M. A.; Marin, C.

    2010-01-01

    Single-walled carbon nanotubes (SWCNTs) prepared by the HiPco process were purified using a modified gas phase purification technique. A TEM-STM holder was used to study the morphological changes of SWCNT ropes as a function of applied voltage. Kink formation, buckling behavior, tubular transformation and eventual breakdown of the system were observed. The tubular formation was attributed to a transformation from SWCNT ropes to multi-walled carbon nanotube (MWCNT) structures. It is likely mediated by the patching and tearing mechanism which is promoted primarily by the mobile vacancies generated due to current-induced heating and, to some extent, by electron irradiation.

  17. Self-assembly of versatile tubular-like In2O3 nanostructures

    International Nuclear Information System (INIS)

    Versatile indium oxide tubular nanostructures (well-aligned nanotube arrays, flower-like tubular structures, and square nanotubes) were fabricated by a facile and reliable chemical vapor deposition (CVD) technique, taking advantage of the self-assembly property and substrate-induced epitaxial growth mechanism. The technique has a few advantages, such as low growth temperature, nonexistence of catalyst, template-free synthesis, direct bonding to the semiconductor substrates, etc. This strategy might extend the approach of synthesizing desirable nanostructures of other important low-melting metal oxides for potential applications

  18. Self-assembly of versatile tubular-like In(2)O(3) nanostructures.

    Science.gov (United States)

    Zhong, Miao; Zheng, Maojun; Ma, Li; Li, Yanbo

    2007-11-21

    Versatile indium oxide tubular nanostructures (well-aligned nanotube arrays, flower-like tubular structures, and square nanotubes) were fabricated by a facile and reliable chemical vapor deposition (CVD) technique, taking advantage of the self-assembly property and substrate-induced epitaxial growth mechanism. The technique has a few advantages, such as low growth temperature, nonexistence of catalyst, template-free synthesis, direct bonding to the semiconductor substrates, etc. This strategy might extend the approach of synthesizing desirable nanostructures of other important low-melting metal oxides for potential applications. PMID:21730485

  19. Study on Defect Detecting and Locating Method of Tubular Cylindrical Conductor

    Directory of Open Access Journals (Sweden)

    Yinchuan Wu

    2013-06-01

    Full Text Available This paper is to present a defect detecting and locating method of tubular cylindrical conductor based on alternating current impedance measurement theory. A defect estimation  can be made through the impedance measurement of some distance on the inner and the outer surfaces of the tubular cylindrical conductor. A defect in the thickness direction can be located by the skin effect influence on impedance and the frequency change in exciting current. The results show that: this method can effectively identify and locate a defect, and therefore should be promoted in the defect detecting of metal materials in other shapes.

  20. Micro-drilling of polymer tubular ultramicroelectrode arrays for electrochemical sensors

    DEFF Research Database (Denmark)

    Kafka, Jan Robert; Skaarup, Steen; Geschke, Oliver;

    2013-01-01

    We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer. Arrays of Ø 100 μm tubular electrodes each having a height of 0.37 ± 0.06 μm were...... reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals...

  1. Modelling and experimental verification on concrete-filled steel tubular columns with L or T section

    Institute of Scientific and Technical Information of China (English)

    LU Xilin; LI Xueping; WANG Dan

    2007-01-01

    Concrete-filled steel tubular columns with L or T sections were analyzed in this paper. According to the confin- ing mechanism, the stress-strain constitutive model was put forward, and calculated results were compared with experi- mental records. After that, the hysteretic rules for the in-filled concrete were constructed, aiming at the analysis on the seis- mic behavior of composite members. The simulation analysis was performed by programming it in Fortran. The models in this paper can be applied in the program of time history analysis on tall buildings with concrete-filled steel tubular columns with L or T sections.

  2. The effect of RAAS blockade on markers of renal tubular damage in diabetic nephropathy

    DEFF Research Database (Denmark)

    Nielsen, Stine; Rossing, Kasper; Hess, Georg;

    2012-01-01

    Blockade of the renin-angiotensin-aldosterone system (RAAS) affects both the glomerulus and tubules. We aimed to investigate the effect of irbesartan on the tubular markers: urinary (u) neutrophil gelatinase associated protein (NGAL), Kidney injury molecule 1 (KIM1) and liver-fatty acid-binding p......Blockade of the renin-angiotensin-aldosterone system (RAAS) affects both the glomerulus and tubules. We aimed to investigate the effect of irbesartan on the tubular markers: urinary (u) neutrophil gelatinase associated protein (NGAL), Kidney injury molecule 1 (KIM1) and liver-fatty acid...

  3. Tubular and glomerular injury in diabetes and the impact of ACE inhibition

    DEFF Research Database (Denmark)

    Nielsen, Stine E; Sugaya, Takeshi; Tarnow, Lise;

    2009-01-01

    OBJECTIVE: We studied tubular and glomerular damage in type 1 diabetic patients by measuring urinary-liver fatty acid binding protein (U-LFABP) and albuminuria. Subsequently, we evaluated the effect of ACE inhibition on U-LFABP in patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS: We......, 46, and 40% with increasing doses of lisinopril (NS). CONCLUSIONS: An early and progressive increase in tubulointerstitial damage as reflected by increased U-LFABP levels occurs in type 1 diabetic patients and is associated with albuminuria. Furthermore, ACE inhibition reduces the tubular...

  4. Cellular interactions via conditioned media induce in vivo nephron generation from tubular epithelial cells or mesenchymal stem cells

    International Nuclear Information System (INIS)

    Highlights: •We have attempted in vivo nephron generation using conditioned media. •Vascular and tubular cells do cross-talks on cell proliferation and tubular changes. •Tubular cells suppress these changes in mesenchymal stem cells. •Tubular cells differentiate mesenchymal stem cells into tubular cells. •Nephrons can be created from implanted tubular cells or mesenchymal stem cells. -- Abstract: There are some successful reports of kidney generation by utilizing the natural course of kidney development, namely, the use of an artificially treated metanephros, blastocyst or ureteric bud. Under a novel concept of cellular interactions via conditioned media (CMs), we have attempted in vivo nephron generation from tubular epithelial cells (TECs) or mesenchymal stem cells (MSCs). Here we used 10× CMs of vascular endothelial cells (VECs) and TECs, which is the first to introduce a CM into the field of organ regeneration. We first present stimulative cross-talks induced by these CMs between VECs and TECs on cell proliferation and morphological changes. In MSCs, TEC-CM suppressed these changes, however, induced cytokeratin expression, indicating the differentiation of MSCs into TECs. As a result, glomerular and tubular structures were created following the implantation of TECs or MSCs with both CMs. Our findings suggest that the cellular interactions via CMs might induce in vivo nephron generation from TECs or MSCs. As a promoting factor, CMs could also be applied to the regeneration of other organs and tissues

  5. Cellular interactions via conditioned media induce in vivo nephron generation from tubular epithelial cells or mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Machiguchi, Toshihiko, E-mail: machiguchi.toshihiko.23u@st.kyoto-u.ac.jp; Nakamura, Tatsuo, E-mail: nakamura@frontier.kyoto-u.ac.jp

    2013-06-07

    Highlights: •We have attempted in vivo nephron generation using conditioned media. •Vascular and tubular cells do cross-talks on cell proliferation and tubular changes. •Tubular cells suppress these changes in mesenchymal stem cells. •Tubular cells differentiate mesenchymal stem cells into tubular cells. •Nephrons can be created from implanted tubular cells or mesenchymal stem cells. -- Abstract: There are some successful reports of kidney generation by utilizing the natural course of kidney development, namely, the use of an artificially treated metanephros, blastocyst or ureteric bud. Under a novel concept of cellular interactions via conditioned media (CMs), we have attempted in vivo nephron generation from tubular epithelial cells (TECs) or mesenchymal stem cells (MSCs). Here we used 10× CMs of vascular endothelial cells (VECs) and TECs, which is the first to introduce a CM into the field of organ regeneration. We first present stimulative cross-talks induced by these CMs between VECs and TECs on cell proliferation and morphological changes. In MSCs, TEC-CM suppressed these changes, however, induced cytokeratin expression, indicating the differentiation of MSCs into TECs. As a result, glomerular and tubular structures were created following the implantation of TECs or MSCs with both CMs. Our findings suggest that the cellular interactions via CMs might induce in vivo nephron generation from TECs or MSCs. As a promoting factor, CMs could also be applied to the regeneration of other organs and tissues.

  6. Composite Epstein-Barr Virus-Associated B-Cell Lymphoproliferative Disorder and Tubular Adenoma in a Rectal Polyp.

    Science.gov (United States)

    Lo, Amy A; Gao, Juehua; Rao, M Sambasivia; Yang, Guang-Yu

    2016-02-01

    Composite tumors are formed when there is intermingling between two components of separate tumors seen histologically. Cases demonstrating composite tubular adenoma with other types of tumors in the colon are rare. Composite tubular adenomas with nonlymphoid tumors including carcinoids, microcarcinoids, and small cell undifferentiated carcinoma have been reported in the literature. The occurrence of composite lymphoma and tubular adenoma within the colorectal tract is extremely rare. Only three cases have been reported and include one case of mantle cell lymphoma and two cases of diffuse large B-cell lymphoma arising in composite tubular adenomas. We present the first case of composite Epstein-Barr virus-associated B-cell lymphoproliferative disorder and tubular adenoma in a rectal polyp with a benign endoscopic appearance.

  7. Insulin's acute effects on glomerular filtration rate correlate with insulin sensitivity whereas insulin's acute effects on proximal tubular sodium reabsorption correlate with salt sensitivity in normal subjects

    NARCIS (Netherlands)

    ter Maaten, JC; Bakker, SJL; Serne, EH; ter Wee, PM; Gans, ROB

    1999-01-01

    Background. Insulin induces increasing distal tubular sodium reabsorption. Opposite effects of insulin to offset insulin-induced sodium retention are supposedly increases in glomerular filtration rate (GFR) and decreases in proximal tubular sodium reabsorption. Defects in these opposing effects coul

  8. para palmito

    Directory of Open Access Journals (Sweden)

    Francisco Paulo Chaimsohn

    2007-01-01

    Full Text Available Densidades de siembra, arreglos espaciales y fertilización en pejibaye (Bactris gasipaes cv Diamantes-10 para palmito. La investigación se llevó a cabo en la Estación Experimental Los Diamantes (Guápiles, Costa Rica, el 3 de octubre del 2003, cuyo objetivo fue la evaluación del efecto de diferentes densidades de siembra (3.333, 5.000 y 6.666 plantas/ha, arreglos espaciales, y diversos métodos de fertilización (química, orgánica, sobre el crecimiento de las plantas de pejibaye para producción de palmito. Se consideraron las variables diámetro y altura del tallo primario y el número de hojas y rebrotes como indicadores de producción. El período de evolución abarcó sólo los primeros 25 meses de crecimiento en el campo. El número de hojas, la altura y el diámetro del tallo no mostraron diferencias de respuesta relevantes. Sólo el número de rebrotes disminuyó al aumentar la densidad de la población, cuando se midió a los 15 meses de edad. El efecto de la fertilización se hizo evidente después de la primera cosecha, realizada a los 20 meses, debido al aumento de la competencia entre plantas, ahora más desarrolladas. Fue entonces cuando la fertilización química indujo la producción de un mayor número y vigor de los rebrotes. Sin embargo, las prácticas evaluadas 25 meses después de la siembra, no habían infl uido hasta ese momento en el número de palmitos cosechados, ni tampoco había afectado las características físicas de los sectores foliar y caulinar del palmito.

  9. Para Leer

    Directory of Open Access Journals (Sweden)

    Adela Sanz Cañibano

    2012-01-01

    Full Text Available Jorge L. Tizón, Ramón Ciurana, M del Carmen Fernández (Comps. Libro de casos. Promoción de la salud mental desde la atención primaria. (Adela Sanz Cañibano Grupo de Expertos en Competencia Intercultural. Instrumento para la valoración de la Competencia Intercultural en la Atención en salud mental. Hacia la equidad en salud. (María Goretti Morón Nozaleda Mariano Hernández Monsalve y Pilar Nieto Degregori (Coords.. Psicoterapia y Rehabilitación de pacientes con psicosis. (Francisco Chicharro Lezcano André du Laurens. De las enfermedades melancólicas. Jourdain Guibelet. Del humor melancólico. (Iñaki Markez Julio José? Segarra Valls. Léxico psico(patológico en la obra de Carlos Castilla del Pino. (Eudoxia Gay Pamos Giorgio Nardone y Alessandro Salvini. El diálogo estratégico. (Fernando Mansilla Izquierdo Michel Foucault. Leçons sur la volonté de savoir, suivi de Le savoir d'Edipe. (Mauricio Jalón Camilo Castelo Branco. La novela de un hombre rico. (Alicia Merisi Kenzaburo Oé. Cuadernos de Hiroshima. (Mauricio Jalón Pascal Quignard. Les solidarités mystérieuses. (Beatriz A. Rubín Documentos en la red (Juan Medrano

  10. Generation of tubular beams of negative hydrogen ions by a surface plasma source

    International Nuclear Information System (INIS)

    The results of experiments on obtaining a tubular beam of hydrogen negative ions from a surface plasma source with emission ring slit of 100 mm diameter are described in the study. Conditions of burning of a high current ring discharge generating effectively hydrogen negative ions with current density up to 2.1 A/cm2 are investigated. The possibility of generation of intensive tubular beams of hydrogen negative ions by surface plasma sources is shown, the 2.4 A ion beam is obtained. The results of preliminary experiments on accelerating tubular beam up to 135 keV are described. Azymuthally uniform current density distribution of intensive tubular beams generated by discharges with a close electron drift in a surface plasma source with emission ring slit, absence of high-frequency oscillations in optimal conditions of sources operation as well as the possibility of the most complete use of generated by the discharge negative ions flow show the prospects of development of these sources for fast atom injectors

  11. Fiber-Based Chitosan Tubular Scaffolds for Soft Tissue Engineering: Fabrication and in Vitro Evaluation

    Institute of Scientific and Technical Information of China (English)

    WANG Aijun; AO Qiang; CAO Wenling; ZHAO Chang; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2005-01-01

    Porous, two-ply tubular chitosan conduits for guided tissue regeneration were fabricated by combining the textile technique (inner layer) with the thermally induced phase separation process (outer layer). A hollow chitosan tube was prepared using an industrial warp knitting process with chitosan yarns. Then, an appropriate diameter mandrel was inserted into the pre-fabricated tube. The tube and the mandrel were dipped into the chitosan solution together, taken out, and freeze-dried. After being neutralized in alkaline solution and dried at room temperature, the mandrel was removed to create the chitosan tubular scaffold. Scanning electron micrographs show that the resulting tubes have a biphasic wall structure, with a fibrous inner layer and a semipermeable outer layer. The swelling properties and the mechanical strength before and after in vitro degradation were investigated. The biocompatibility of the scaffolds was also investigated by co-culturing neuroblastoma cells (N2A, mouse) with the scaffolds. The results suggest that these chitosan tubular scaffolds are useful for the regeneration of tissues requiring a tubular scaffold.

  12. Defective proximal tubular function in a patient with I-cell disease.

    NARCIS (Netherlands)

    Bocca, G.; Monnens, L.A.H.

    2003-01-01

    A girl with a proven diagnosis of I-cell disease is presented. Proximal tubular dysfunction was characterized by increased excretion of low molecular proteins, aminoaciduria, hyperphosphaturia, and high/slightly increased urinary calcium. The concentration of 1,25-dihydroxycalciferol in serum was in

  13. Type IV renal tubular acidosis and spironolactone therapy in the elderly.

    OpenAIRE

    O'Connell, J. E.; Colledge, N. R.

    1993-01-01

    Spironolactone therapy is a well-known cause of hyperkalaemia, but in susceptible patient, it may also be associated with metabolic acidosis. We report a case of severe renal tubular acidosis (Type IV) with life-threatening hyperkalaemia caused by spironolactone, and discuss the mechanisms by which this may occur.

  14. Hereditary tubular transport disorders: implications for renal handling of Ca2+ and Mg2+

    DEFF Research Database (Denmark)

    Dimke, Henrik; Hoenderop, Joost G; Bindels, René J;

    2010-01-01

    change tubular transport of Ca2+ and Mg2+. In the distal convolutions, several proteins involved in Mg2+ transport have been identified [TRPM6 (transient receptor potential melastatin 6), proEGF (pro-epidermal growth factor) and FXYD2 (Na+/K+-ATPase gamma-subunit)]. In addition, conditions...

  15. 49 CFR 230.55 - Tubular type water and lubricator glasses and shields.

    Science.gov (United States)

    2010-10-01

    ...) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Water Glasses and Gauge Cocks § 230.55 Tubular type water and lubricator... maintained. (c) Location and maintenance. Water glasses and water glass shields shall be so...

  16. Tubular and Glomerular Injury in Diabetes and the Impact of ACE Inhibition

    OpenAIRE

    Nielsen, Stine E.; Sugaya, Takeshi; Tarnow, Lise; Lajer, Maria; Schjoedt, Katrine J.; Astrup, Anne Sofie; Baba, Tsuneharu; Parving, Hans-Henrik; Rossing, Peter

    2009-01-01

    OBJECTIVE We studied tubular and glomerular damage in type 1 diabetic patients by measuring urinary–liver fatty acid binding protein (U-LFABP) and albuminuria. Subsequently, we evaluated the effect of ACE inhibition on U-LFABP in patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS We studied Caucasians with type 1 diabetes: 58 with normoalbuminuria (urinary albumin

  17. Photonic band gaps in materials with triply periodic surfaces and related tubular structures

    NARCIS (Netherlands)

    Michielsen, K; Kole, JS

    2003-01-01

    We calculate the photonic band gap of triply periodic bicontinuous cubic structures and of tubular structures constructed from the skeletal graphs of triply periodic minimal surfaces. The effect of the symmetry and topology of the periodic dielectric structures on the existence and the characteristi

  18. Geometry optimization of tubular dielectric elastomer actuators with anisotropic metallic electrodes

    DEFF Research Database (Denmark)

    Rechenbach, Björn; Willatzen, Morten; Sarban, R.;

    2014-01-01

    This paper presents an experimentally verified static three-dimensional model for core free tubular dielectric elastomer actuators with anisotropic compliant metal electrodes. Due to the anisotropy of the electrodes, the performance (force versus voltage, force versus stroke, and stroke versus vo...

  19. 78 FR 77420 - Certain Oil Country Tubular Goods From the Republic of Turkey: Preliminary Negative...

    Science.gov (United States)

    2013-12-23

    ... Tubular Goods from India, the Republic of Korea, the Republic of the Philippines, Saudi Arabia, Taiwan.... Department of Commerce, 14th Street and Constitution Avenue NW., Washington, DC 20230; telephone: (202) 482... Duty Investigations, 78 FR 45505 (July 29, 2013). \\2\\ Maverick Tube Corporation, United States...

  20. Porous layer open tubular columns with immobilized trypsin for protein digestion

    OpenAIRE

    Knob, R.

    2013-01-01

    We have developed a monolithic porous layer open tubular (PLOT) column with immobilized trypsin for protein digestion. The PLOT column was prepared in a 10 (mikro)m ID fused silica capillary. Trypsin was immobilized on the monolithic surface and the developed enzyme reactor was used for protein digestion followed by on-line ESI/MS analysis.

  1. Tubular engraftment and myofibroblast differentiation of recipient-derived cells after experimental kidney transplantation

    NARCIS (Netherlands)

    Broekema, Martine; Harmsen, Martin C.; Koerts, Jasper A.; Van Kooten, Theo G.; Navis, Gerjan; Van Luyn, Marja J. A.; Popa, Eliane R.

    2007-01-01

    Background. In human renal allografts, recipient-derived cells engrafted in various kidney substructures, have been detected in the long term after transplantation. Here we investigated tubular engraftment and myofibroblast differentiation of recipient-derived cells at short term after experimental

  2. 78 FR 56865 - Certain Oil Country Tubular Goods From India and Turkey: Postponement of Preliminary...

    Science.gov (United States)

    2013-09-16

    ..., income tax incentives, and the provision of goods and services for less than adequate remuneration. Due... Investigations, 78 FR 45502 (July 29, 2013). Postponement of Due Date for the Preliminary Determination Section... International Trade Administration Certain Oil Country Tubular Goods From India and Turkey: Postponement...

  3. [Lumen morphogenesis and molecular mechanisms in tubular organs during zebrafish embryonic development].

    Science.gov (United States)

    Xiao, Chun; Hu, Huo-Zhen; Mo, Xian-Ming

    2013-04-01

    A network tubular system is an important structure in the body and organ of metazoa. The lumen of tube is fundamental units in the structure, which serve to transport material, divide the organ into different functional compartments and separate the organ from the environment. The defects of lumen formation will lead to abnormalities of the organ morphogenesis and disorder of the function. Zebrafish (Danio rerio)is an important model for development research. Meanwhile easy observation of tubular organ, the relevant mutants, and transgene linages make zebrafish to become an excellent model to study the formation of lumen in the tubular organs, including the blood vessels, neural tube, gut, exocrine pancreas, and pronephric duct, which undergo the typical morphogenesis of lumen that is involved in the organs' development. The process of lumen formation is mainly consisted of induction of extracellular signals, polarization of epithelial cell, directional transportation in the polar cells, the aggregation and transportation of fluid in the lumen, and the reconstruction of cytoskeleton in polar cells and controlled by the precise and complicated molecular networks during embryonic development. This review will summarize our current knowledge on lumen morphogenesis in four kinds of typical tubular organs during zebrafish embryonic development and the related molecular mechanisms as well as to supply helpful reference to the future studies.

  4. Safe design of cooled tubular reactors for exothermic multiple reactions: Multiple-reaction networks

    NARCIS (Netherlands)

    Westerink, E.J.; Westerterp, K.R.

    1988-01-01

    The model of the pseudo-homogeneous, one-dimensional cooled tubular reactor is applied to a multiple-reaction network. It is demonstrated for a network which consists of two parallel and two consecutive reactions. Three criteria are developed to obtain an integral yield which does not deviate more t

  5. Gender Difference of Cadmium-induced Renal Tubular Dysfunction for Inhabitants in Toyama,Japan

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Objective The aim of the present study was to compare the gender differencefor cadmium-induced renal tubular dysfunction between the male and female inhabitants. MethodsUrinary β2-microglobulin was measured in 299 male (94%) and 342 female (92%) inhabitants aged54 - 72 years,and the development of renal tubular dysfunction for 11 years was studied in the 62married couples from them. Results A significantly higher cumulative incidence was found in bothmen and women in cudmium-polluted area,showing 68. 4% in men and 64.8% in women compared to15.3 % in men and 5.9 % in women in the reference areas. Relative risk of renal tubular dysfunctionin females (11.0) was higher than males (4.5). The ratios of urinary β2-nicroglobulin and glucosewere higher in women than those in men in both the cadmium-polluted areas and the reference areas.Conclusion Although almost identical incidences were detected between men and wonen, the changesin excretion of β2-microglobulin and glucose was greater in women than those in men. These findings sug-gest that renal tubular dysfunction might be more progressive in women than that in men.

  6. Classification of capped tubular viral particles in the family of Papovaviridae

    Science.gov (United States)

    Keef, T.; Taormina, A.; Twarock, R.

    2006-04-01

    A vital constituent of a virus is its protein shell, called the viral capsid, that encapsulates and hence provides protection for the viral genome. Viral capsids are usually spherical, and for a significant number of viruses they exhibit overall icosahedral symmetry. The corresponding surface lattices, that encode the locations of the capsid proteins and intersubunit bonds, can be modelled by viral tiling theory. It has been shown in vitro that under a variation of the experimental boundary conditions, such as the pH value and salt concentration, tubular particles may appear instead of, or in addition to, spherical ones. In order to develop models that describe the simultaneous assembly of both spherical and tubular variants, and hence study the possibility of triggering tubular malformations as a means of interference with the replication mechanism, viral tiling theory has to be extended to include tubular lattices with end caps. We focus here on the case of Papovaviridae, which play a distinguished role from the viral structural point of view as they correspond to all pentamer lattices, i.e. lattices formed from clusters of five protein subunits throughout. These results pave the way for a generalization of recently developed assembly models.

  7. Classification of capped tubular viral particles in the family of Papovaviridae

    Energy Technology Data Exchange (ETDEWEB)

    Keef, T [Department of Mathematics, University of York, York YO10 5DD (United Kingdom); Taormina, A [Department of Mathematical Sciences, University of Durham, Durham DH1 3LE (United Kingdom); Twarock, R [Department of Mathematics, University of York, York YO10 5DD (United Kingdom); Carlos [Istituto di Chimica del Riconoscimento Molecolare, CNR, Via Mario Bianco 9, 20131 Milan (Italy); Department of Biology, University of York, York YO10 5DD (United Kingdom)

    2006-04-12

    A vital constituent of a virus is its protein shell, called the viral capsid, that encapsulates and hence provides protection for the viral genome. Viral capsids are usually spherical, and for a significant number of viruses they exhibit overall icosahedral symmetry. The corresponding surface lattices, that encode the locations of the capsid proteins and intersubunit bonds, can be modelled by viral tiling theory. It has been shown in vitro that under a variation of the experimental boundary conditions, such as the pH value and salt concentration, tubular particles may appear instead of, or in addition to, spherical ones. In order to develop models that describe the simultaneous assembly of both spherical and tubular variants, and hence study the possibility of triggering tubular malformations as a means of interference with the replication mechanism, viral tiling theory has to be extended to include tubular lattices with end caps. We focus here on the case of Papovaviridae, which play a distinguished role from the viral structural point of view as they correspond to all pentamer lattices, i.e. lattices formed from clusters of five protein subunits throughout. These results pave the way for a generalization of recently developed assembly models.

  8. The Association of Albuminuria With Tubular Reabsorption of Uric Acid : Results From a General Population Cohort

    NARCIS (Netherlands)

    Scheven, Lieneke; Joosten, Michel M.; de Jong, Paul E.; Bakker, Stephan J. L.; Gansevoort, Ron T.

    2014-01-01

    Background-Elevated albuminuria as well as an increased serum uric acid concentration is associated with poor cardiovascular outcome. We questioned whether these 2 variables (albuminuria and serum uric concentration) may be interrelated via tubular uric acid reabsorption. Methods and Results-Include

  9. The choice between cooled tubular reactor models: analysis of the hot spot

    NARCIS (Netherlands)

    Westerink, E.J.; Koster, N.; Westerterp, K.R.

    1990-01-01

    The applicability of the one-dimensional pseudo-homogeneous model of the cooled tubular reactor is studied. Using the two-dimensional model as the more accurate one we compared both models by studying the influence of the design and operating variables on the conditions in the hot spot of the reacto

  10. Preparation of Ethylene Glycol Monoethyl Ether Acetate Using a Tubular Reactor

    Institute of Scientific and Technical Information of China (English)

    蔡振云; 卢祖国; 李小波

    2003-01-01

    Ethylene glycol monoethyl ether acetate (EGEA), an excellent solvent, is prepared with ethylene oxide (EO) and ethyl acetate (EA) in a tubular reactor under suitable reaction condition. The single circulation yield can reach 81%. This technology is not only safe but also makes it possible to continuously produce EGEA in industry,with low content of high boiling point by-products.

  11. Internal ballistics of recoilless high-low pressure guns using hepta-tubular powders

    Directory of Open Access Journals (Sweden)

    M. C. Gupta

    1960-04-01

    Full Text Available In this paper, the theory of recoilless high-low pressure guns has been discussed by taking the form function and the results have been applied to the case of hepta-tubular powders. The results for high-low pressure guns follow as a particular case.

  12. Effect of adrenomedullin on rat renal tubular epithelial cell apoptosis induced by hypoxiareoxygenation and its mechanism

    Institute of Scientific and Technical Information of China (English)

    苏晓乐

    2013-01-01

    Objective To investigate the effect of adrenomedullin on rat renal tubular epithelial cell line (NRK-52E) apoptosis induced by hypoxia-reoxygenation (HR) injury and its mechanism.Methods NRK-52E cells were cultured and randomly allotted to the following 4 groups:control group,HR group,empty plasmid+HR group,

  13. Elliptical modelling of hysteresis operating characteristics in a dielectric elastomer tubular actuator

    Science.gov (United States)

    Tian, Pengfei; Jones, Richard W.; Yu, Fei

    2016-07-01

    A dielectric elastomer (DE) tubular actuator, based on compliant metal electrode technology, exhibits hysteresis-like characteristics when driven with a low power rated high voltage power supply (HVPS). This behavior occurs mainly because the DE actuator acts as a capacitive load compromising the ‘slew rate’ of the HVPS during the actuator’s operation. The motivation of this contribution is to investigate the use of elliptical modelling approaches for capturing the hysteresis characteristics exhibited by the DE tubular actuator when it is driven by a low cost low power rated HVPS. The DE tubular actuator considered in this work demonstrates asymmetric hysteresis behaviour due to the nonlinear voltage–strain behaviour of the actuator. A linearization filter placed in series with the actuator (during its operation) ensures a symmetric hysteresis characteristic that can then be modelled using an ellipse-based approach. Elliptical models come in many forms with the two most popular being the constrained general conic form and the general parametric form. Elliptical-based hysteresis model fits are carried out on experimental data obtained from the application of periodic input voltages, at a number of different low-frequencies, to the tubular actuator. The range of frequencies used is related to the possible use of the tubular actuator for attenuating low frequency vibration during DE actuator-based load positioning applications. Constrained conic and general parametric forms of elliptical model are used for modelling the hysteresis characteristics of the DE actuator and rate dependent models developed based on both approaches. The sensitivity of both of these rate dependent models to small inaccuracies in model parameters was then investigated. The general parametric form was found to be more robust in this respect.

  14. Genome-wide profiling to analyze the effects of FXR activation on mouse renal proximal tubular cells.

    Science.gov (United States)

    Gui, Ting; Gai, Zhibo

    2015-12-01

    To assess the effect of farnesoid X receptor (FXR), a bile acid nuclear receptor, on renal proximal tubular cells, primary cultured mouse kidney proximal tubular cells were treated with GW4064 (a FXR agonist) or DMSO (as controls) overnight. Analysis of gene expression in the proximal tubular cells by whole genome microarrays indicated that FXR activation induced genes involved in fatty acid degradation and oxidation reduction. Among them, genes involved in glutathione metabolism were mostly induced. Here we describe in details the contents and quality controls for the gene expression and related results associated with the data uploaded to Gene Expression Omnibus (accession number GSE70296). PMID:26697325

  15. Genome-wide profiling to analyze the effects of FXR activation on mouse renal proximal tubular cells

    Directory of Open Access Journals (Sweden)

    Ting Gui

    2015-12-01

    Full Text Available To assess the effect of farnesoid X receptor (FXR, a bile acid nuclear receptor, on renal proximal tubular cells, primary cultured mouse kidney proximal tubular cells were treated with GW4064 (a FXR agonist or DMSO (as controls overnight. Analysis of gene expression in the proximal tubular cells by whole genome microarrays indicated that FXR activation induced genes involved in fatty acid degradation and oxidation reduction. Among them, genes involved in glutathione metabolism were mostly induced. Here we describe in details the contents and quality controls for the gene expression and related results associated with the data uploaded to Gene Expression Omnibus (accession number GSE70296.

  16. Overendocytosis of gold nanoparticles increases autophagy and apoptosis in hypoxic human renal proximal tubular cells

    Directory of Open Access Journals (Sweden)

    Ding F

    2014-09-01

    Full Text Available Fengan Ding,1 Yiping Li,1 Jing Liu,1 Lei Liu,1 Wenmin Yu,1 Zhi Wang,1 Haifeng Ni,2 Bicheng Liu,2 Pingsheng Chen1,2 1School of Medicine, Southeast University, Nanjing, People’s Republic of China; 2Institute of Nephrology, The Affiliated Zhongda Hospital, Southeast University, Nanjing, People’s Republic of China Background: Gold nanoparticles (GNPs can potentially be used in biomedical fields ranging from therapeutics to diagnostics, and their use will result in increased human exposure. Many studies have demonstrated that GNPs can be deposited in the kidneys, particularly in renal tubular epithelial cells. Chronic hypoxic is inevitable in chronic kidney diseases, and it results in renal tubular epithelial cells that are susceptible to different types of injuries. However, the understanding of the interactions between GNPs and hypoxic renal tubular epithelial cells is still rudimentary. In the present study, we characterized the cytotoxic effects of GNPs in hypoxic renal tubular epithelial cells.Results: Both 5 nm and 13 nm GNPs were synthesized and characterized using various biophysical methods, including transmission electron microscopy, dynamic light scattering, and ultraviolet–visible spectrophotometry. We detected the cytotoxicity of 5 and 13 nm GNPs (0, 1, 25, and 50 nM to human renal proximal tubular cells (HK-2 by Cell Counting Kit-8 assay and lactate dehydrogenase release assay, but we just found the toxic effect in the 5 nm GNP-treated cells at 50 nM dose under hypoxic condition. Furthermore, the transmission electron microscopy images revealed that GNPs were either localized in vesicles or free in the lysosomes in 5 nm GNPs-treated HK-2 cells, and the cellular uptake of the GNPs in the hypoxic cells was significantly higher than that in normoxic cells. In normoxic HK-2 cells, 5 nm GNPs (50 nM treatment could cause autophagy and cell survival. However, in hypoxic conditions, the GNP exposure at the same condition led to the

  17. El liberalsocialismo para Bobbio y para nosotros

    OpenAIRE

    Bovero, Michelangelo

    2006-01-01

    Partiendo de las ideas sobre el liberalsocialismo en el pensamiento de Norberto BOBBIO y hallando en el ámbito del constitucionalismo el terreno propicio, no ya para un compromiso, sino para una forma de reconciliación entre la tradición liberal y la socialista, el autor propone una caracterización del liberalsocialismo articulada en dos niveles: en un “liberalsocialismo mínimo” (o liberalsocialismo para la democracia), entendido como un “mínimo indispensable para la democracia”, y en un “lib...

  18. Multi-pass spinning of thin-walled tubular part with longitudinal inner ribs

    Institute of Scientific and Technical Information of China (English)

    JIANG Shu-yong; ZHENG Yu-feng; REN Zheng-yi; LI Chun-feng

    2009-01-01

    Based on the process experiments, micrography analysis was dedicated to advancing the understanding of plastic flow of the metal in backward ball spinning of thin-walled tubular part with longitudinal inner ribs. Micrography analysis reveals that severe plastic deformation leads to grain refinement, grain orientation and grain flow line of the spun part. Based on rigid-plastic finite element method, DEFORME3D finite element code was used to simulate and analyze multi-pass backward ball spinning of thin-walled tubular part with longitudinal inner ribs. Finite element simulation results involve the distributions of the strain, the shape variation of the inner ribs as well as the prediction of the spinning loading.

  19. Concurrent feline immune-complex nephritis. Tubular antigen-positive and renal amyloidosis.

    Science.gov (United States)

    Saegusa, S; Shimizu, F; Nagase, M; Kasegawa, A

    1979-08-01

    We describe tubular antigen-positive immune-complex nephritis in a case of feline renal amyloidosis. Amyloid deposition was observed in mesangial area, and thickening of capillary walls was shown in the majority of the glomeruli. This case was also characterized with typical fluorescent granular depositions of cat IgG and C3 along the glomerular capillary walls as seen in human membranous glomerulonephritis. The fluorescent pattern of tubular antigen was identical with that of IgG and C3. Electron micrograph showed the thickening and irregularity of glomerular basement membranes, fusion of foot processes, and deposits of electron-dense or sometimes translucent materials, mostly in the intramembranous location. The causal sequence of the coincidental deposition of amyloid and immune complexes is discussed. PMID:157110

  20. Small intestinal tubular adenoma in a pediatric patient with Turner syndrome

    Science.gov (United States)

    Tang, Wen-Juan; Huang, Ying; Chen, Lian; Zheng, Shan; Dong, Kui-Ran

    2013-01-01

    Turner syndrome (TS) is a female chromosomal disorder caused by the lack of an X chromosome. The loss of this chromosome may result in the deficiency of tumor-suppressive or DNA repair genes, leading to tumorigenesis. Recombinant human growth hormone (GH) has been popularly used for treatment in TS patients for growth promotion. Although treatment with GH has been correlated with precancerous and cancerous lesions in TS children, its associations with gastric or colonic tumors, especially ileal tubular adenomas, have not been reported frequently. We here report a case of a 16-year-old patient with TS and tubular adenoma of the small intestine. Whether the ileal adenoma was caused by TS itself or GH therapy was discussed. PMID:23599636

  1. Protection of Renal Tubular Cells by Antioxidants: Current Knowledge and New Trends

    Directory of Open Access Journals (Sweden)

    Azar Baradaran

    2015-01-01

    Full Text Available Acute renal damage mainly develops following toxic or ischemic insults and is defined as acute. These damages have largely been attributed to oxidative stress. Recently much attention has been directed toward decreased renal tubular cell regeneration during tubular cell injury. Antioxidants have recently been the focus of researchers and scientists for prevention and treatment of various oxidative stress-related conditions, including renal toxicities. Although free radicals are known to contribute in kidney injury and abundant researches, particularly laboratory trials, have shown the beneficial effects of antioxidants against these complications, long term clinical trials do not uniformly confirm this matter,especially for single antioxidant consumption such as vitamin C. The aim of this paper is to discuss the possible explanation of this matter.

  2. Preparation of electrolyte membranes for micro tubular solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Yttria-stabilized zirconia (YSZ) micro tubular electrolyte membranes for solid oxide fuel cells (SOFCs) were prepared via the combined wet phase inversion and sintering technique. The as-derived YSZ mi- cro tubes consist of a thin dense skin layer and a thick porous layer that can serve as the electrode of fuel cells. The dense and the porous electrolyte layers have the thickness of 3-5 μm and 70-90 μm, respectively, while the inner surface porosity of the porous layer is higher than 28.1%. The two layers are perfectly integrated together to preclude the crack or flake of electrolyte film from the electrode. The presented method possesses distinct advantages such as technological simplicity, low cost and high reliability, and thus provides a new route for the preparation of micro tubular SOFCs.

  3. SIDE-BY-SIDE TESTS OF DIFFERENTLY DESIGNED EVACUATED TUBULAR COLLECTORS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Dragsted, Janne; Furbo, Simon

    2007-01-01

    Six differently designed evacuated tubular collectors, ETCs, utilizing solar radiation from all directions, have been investigated experimentally. The evacuated tubular solar collectors investigated include one SLL all-glass ETC from Tshinghua Solar Co., four heat pipe ETCs from Sunda Technolgoy Co....... and one all-glass ETC with heat pipe from Exoheat AB. The collectors have been investigated side-by-side in an outdoor test facility for a long period. During the measurements, the operating conditions – such as weather conditions, inlet and mean solar collector fluid temperatures have been the same. Thus...... a direct performance comparison is possible. The results of the measurements will be presented in this paper. Among other things, the influence on the thermal performance of the absorber design will be explained. Further, it will be illustrated how the thermal performances of the different collector types...

  4. Copper recovery in a bench-scale carrier facilitated tubular supported liquid membrane system

    Directory of Open Access Journals (Sweden)

    Makaka S.

    2010-01-01

    Full Text Available The extraction of copper ions in a tubular supported liquid membrane using LIX 984NC as a mobile carrier was studied, evaluating the effect of the feed characteristics (flowrate, density, viscosity on the feedside laminar layer of the membrane. A vertical countercurrent, double pipe perspex benchscale reactor consisting of a single hydrophobic PVDF tubular membrane mounted inside was used in all test work. The membrane was impregnated with LIX 984NC and became the support for this organic transport medium. Dilute Copper solution passed through the centre pipe and sulphuric acid as strippant passed through the shell side. Copper was successfully transported from the feedside to the stripside and from the data obtained, a relationship between Schmidt, Reynolds and Sherwood number was achieved of.

  5. Preparation of electrolyte membranes for micro tubular solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    TAN XiaoYao; YIN WeiNing; MENG Bo; MENG XiuXia; YANG NaiTao; MA ZiFeng

    2008-01-01

    Yttria-stabilized zirconia (YSZ) micro tubular electrolyte membranes for solid oxide fuel cells (SOFCs) were prepared via the combined wet phase inversion and sintering technique. The as-derived YSZ mi-cro tubes consist of a thin dense skin layer and a thick porous layer that can serve as the electrode of fuel cells. The dense and the porous electrolyte layers have the thickness of 3-5 μm and 70-90 μm, respectively, while the inner surface porosity of the porous layer is higher than 28.1%. The two layers are perfectly integrated together to preclude the crack or flake of electrolyte film from the electrode. The presented method possesses distinct advantages such as technological simplicity, low cost and high reliability, and thus provides a new route for the preparation of micro tubular SOFCs.

  6. The influence of angiotensin-converting enzyme inhibition on renal tubular function in progressive chronic nephropathy

    DEFF Research Database (Denmark)

    Kamper, A L; Holstein-Rathlou, N H; Leyssac, P P;

    1996-01-01

    on progression of renal failure. The pattern of proteinuria was followed over the first 9 months. At baseline, the glomerular filtration rate (GFR) was 5 to 68 mL/min. Absolute proximal tubular reabsorption rate of fluid (APR), estimated as the difference between GFR and C(Li), was 1 to 54 mL/min. Calculated...... fractional proximal reabsorption (FPR) was moderately subnormal. During the study, GFR decreased and sodium clearance was unchanged; fractional excretion of sodium therefore increased. In the group of patients randomized to treatment with enalapril (n = 34), GFR at 1 month was 83% (P ... with conventional antihypertensive drugs (n = 35), C(Li) was unchanged until severe reduction in GFR, APR and FPR decreased gradually, and potassium clearance was almost unchanged. These differences in tubular function between the two treatment regimens were significant (P

  7. Dynamic Behavior Analysis of the Glomerulo-Tubular Balance Mediated by the Efferent Blood Viscosity

    Science.gov (United States)

    Espinel, Andrea; Rivadeneira, Pablo S.; Costanza, Vicente; Amorena, Carlos

    In this paper, a mathematical model of the dynamics of a single-nephron function relating glomerulo-tubular balance, tubule-glomerular feedback, and peritubular blood viscosity is developed. Based upon experimental data, the model shows that complex behaviors of the nephron can be modulated by changes in the efferent arteriole blood viscosity. The main hypothesis is that the reabsorbed mass flow is modulated by the hematocrit of the efferent arteriole, in addition to the Starling forces. From a mathematical perspective, these behaviors can be explained by a bifurcation diagram analysis where the efferent blood viscosity is taken as the bifurcation parameter. This analytical description allows to predict changes in proximal convoluted tubule reabsorption, following changes in peritubular capillary viscosity generated by periodic changes in the glomerular filtration rate. Thus, the model links the tubule-glomerular feedback with the glomerular tubular balance.

  8. Pathogenic role of glomerulo-tubular junction stenosis in glomerulocystic disease.

    Science.gov (United States)

    Hotta, O; Sato, M; Furuta, T; Taguma, Y

    1999-03-01

    Glomerulocystic disease is an uncommon cystic renal condition characterized by cystic dilatation forming a glomerular cyst. The pathogenesis of this familial disease is unknown. We performed a serial section study using a biopsy specimen of a 16-year old female patient with glomerular cystic disease who had a family history of end stage renal failure. A total of 14 different glomeruli were analyzed, four of which exhibited a cystic appearance. Five glomerulotubular junctions were observed by serial sections, two of which had a stenotic appearance where glomerular cystic changes and periglomerular fibrosis were observed concomitantly. There were no such cystic glomerular changes in the other three glomeruli with non-stenotic glomerulo-tubular junctions. These findings suggest that the glomerular cystic lesion develops as a consequence of glomerulo-tubular junctional stenosis probably caused by periglomerular fibrosis.

  9. Tubular depressed cladding waveguide laser realized in Yb: YAG by direct inscription of femtosecond laser

    International Nuclear Information System (INIS)

    We report on the fabrication of tubular depressed cladding waveguides in single crystalline Yb:YAG by the direct femtosecond laser writing technique. Full control over the confined light spatial distribution is demonstrated by the photoinscription of high index contrast waveguides with tubular configuration. Under optical pumping, highly efficient laser oscillation in depressed cladding waveguide at 1030 nm is demonstrated. The maximum output power obtained is 68 mW with a slope efficiency of 35% for an outcoupling transmission of 50%. A slope efficiency as high as 44% is realized when the coupling output ratio is 91% and a low lasing threshold of 70 mW is achieved with the output coupling mirror of 10%. (paper)

  10. Observer Design for a Class of Exothermal Plug-Flow Tubular Reactors

    Directory of Open Access Journals (Sweden)

    Nadia Barje

    2013-08-01

    Full Text Available A semi-linear reduced-order state estimator is presented to reconstruct approximately the state variable initially unknown of a class of nonlinear tubular reactors models, namely the exothermal plug-flow tubular reactor involving sequential reactions for which the kinetics depends on both the temperature and the reactant concentration. Our conception is based on bounded observations and the analysis of the nonlinear set of partial differential equations. It is shown that the given  observer design admits a global unique solution and ensures asymptotic state estimator with exponentially decay error, when only the temperature is available for measurement at the reactor outlet. Simulation results are also presented showing the effectiveness of the proposed observer design.

  11. Design of Funnel Port Tubular Propellant Grain for Neutral Burning Profile in Rockets

    Directory of Open Access Journals (Sweden)

    Himanshu Shekhar

    2009-09-01

    Full Text Available Radial outward burning tubular propellant grain gives progressive burning profile, but trimming port at one end to conical form gives close to neutral burning profile. Though this configuration is easy to realize, but closeform burnback equation for performance prediction of such propellant geometry is not available. In this paper, close-form burnback equation for conically trimmed tubular propellant grain is developed. One propellant grain is also evaluated and performance matching to prediction by developed formulation is realised. Parametric study for different aspect ratio (L/D, diameter ratio (d/D and slant angle (q is carried out for a typical configuration and variation is explained. The developed formulation is simple, handy, easy and quick.Defence Science Journal, 2009, 59(5, pp.494-498, DOI:http://dx.doi.org/10.14429/dsj.59.1550

  12. PROCESSING AND CHARACTERIZATION OF TUBULAR CERAMIC SUPPORT FOR MICROFILTRATION MEMBRANE PREPARED FROM PYROPHYLLITE CLAY

    Directory of Open Access Journals (Sweden)

    Abedallah Talidi

    2011-09-01

    Full Text Available Tubular macroporous support for ceramic microfiltration membranes were prepared by extrusion followed by sintering of the low cost pyrophyllite clay. Clay powders mixed with some organic additives can be extruded to form a porous tubular support. The average pore size of the membrane is observed to increase from 5 µm to 10.8 µm when sintering temperature increase from 900 °C to 1200 °C. However, with the increase in temperature from 900 °C to 1200 °C, the support porosity is reduced from 47% to 30% and flexural strength is increased from 4 MPa to 17 MPa. The fabricated macro-porous supports are expected to have potential applications in the pre-treatment and also can be used like support for membranes of ultra-filtration.

  13. Performance evaluation of fractional-slot tubular permanent magnet machines with low space harmonics

    Directory of Open Access Journals (Sweden)

    Wang Jiabin

    2015-12-01

    Full Text Available This paper evaluates the perforamnce of fractional-slot per pole winding configurations for tubular permanent magnet (PM machines that can effectively eliminate the most undesirable space harmonics in a simple and cost-effective manner. The benefits of the proposed machine topology winding configurations are illustrated through comparison with 9-slot, 10-pole tubular PM machine developed for a free piston energy converter under the same specification and volumetric constraints. It has been shown that the proposed machine topology results in more than 7 times reduction in the eddy current loss in the mover magnets and supporting tube, and hence avoids potential problem of excessive mover temperature and risk of demagnetization.

  14. Renal hyperconcentration of /sup 99m/Tc-HEDP in experimental acute tubular necrosis

    International Nuclear Information System (INIS)

    The effect of transient renal ischemia on renal concentration and distribution of /sup 99m/Tc-HEDP, /sup 99m/Tc-DMSA, and /sup 99m/Tc-DTPA was compared in rabbits with acute tubular necrosis. Scintigrams were obtained after injection in normal rabbits or ones with unilateral or bilateral ischemia. /sup 99m/Tc-HEDP concentration in ischemic tissue was 8 to 18 times normal 1 to 4 hrs after injection, and the resulting images delineated the morphological changes in the ischemic kidneys more accurately than those obtained with DMSA or DTPA. Calcium concentration in the ischemic kidneys increased sixfold. /sup 99m/Tc-HEDP may be useful in evaluation of renal failure secondary to tubular injury

  15. Differentiation between renal allograft rejection and acute tubular necrosis by renal scan

    Energy Technology Data Exchange (ETDEWEB)

    Delmonico, F.L.; McKusick, K.A.; Cosimi, A.B.; Russell, P.S.

    1977-04-01

    The usefulness of the renal scan in diagnosing technical complications in the transplant patient is well established. However, the ability of the renal scan to differentiate between acute rejection and acute tubular necrosis has remained uncertain. We have evaluated the effectiveness of the /sup 99m/Tc DTPA computer-derived time-activity curve of renal cortical perfusion, as well as data obtained from scintillation camera images, in making such diagnoses. Fifteen patients with a clinical diagnosis of either acute rejection or acute tubular necrosis, or both, were studied retrospectively. Technetium scan diagnoses did not agree with the clinical assessment in nine of the patients. Thus selection of a course of treatment should not be based on data obtained from the scan alone.

  16. Estudo teórico experimental de ligações "T" e "KT", em perfis tubulares de aço Theoretical and experimental study on "T" and "KT" tubular steel joints

    Directory of Open Access Journals (Sweden)

    Francisco Canazart Mendes

    2012-06-01

    Full Text Available Nesse trabalho, é apresentado um estudo de ligações soldadas dos tipos K e KT, com barras afastadas, formadas por perfis tubulares de aço estrutural, sem costura, de seção transversal retangular no banzo e circular para demais membros. Para esse estudo, foram desenvolvidas análise analítica e análise numérica das ligações. Também foram desenvolvidos ensaios experimentais em protótipos em escala real e ensaios de tensões residuais no perfil retangular do banzo. Os ensaios dos protótipos das ligações visaram à obtenção do comportamento, carga última e modo de colapso da ligação. A análise numérica em elementos finitos envolveu a geração, a análise e a calibração, a partir dos resultados obtidos nos ensaios experimentais. O modelo foi constituído de forma que representasse o comportamento e a capacidade de carga das ligações ensaiadas experimentalmente. Os resultados foram apresentados de modo a comparar os dados obtidos experimentalmente com os diversos modelos numéricos gerados, com e sem o cordão de solda e sem as imperfeições geométricas. As análises realizadas apresentam boa correlação com os resultados experimentais.This work presents a study of welded T and KT gap joints, formed by a seamless hollow section with rectangular hollow chord sections and circular hollow sections for the members. The developed study considers theoretical and numerical analyses for the joints, experimental tests in full scale prototypes, and tests for residual stress in the rectangular hollow section. The experimental results were used in order to obtain the overall joint behavior, ultimate load, and collapse mode. The numerical analysis using finite elements methods involved the generation, testing and calibration of the experimental results. The model represents the behavior and load capacity of the tested joints. The numerical models considered or not the welding and geometric imperfections and the results were compared

  17. Protective mechanism of NALP3-siRNA on rat renal tubular epithelial cells from hypoxia/reoxygenation injury

    Institute of Scientific and Technical Information of China (English)

    冯娟

    2013-01-01

    Objective To explore the mechanism of protecting cells from hypoxia/reoxygenation(H/R) injury by constructing specific small interference RNA(siRNA) to inhibit NALP3 expression in rat renal tubular epithelial

  18. Cleistanthus collinus induces type I distal renal tubular acidosis and type II respiratory failure in rats

    OpenAIRE

    Maneksh, Delinda; Sidharthan, Anita; Kettimuthu, Kavithapriya; Kanthakumar, Praghalathan; Lourthuraj, Amala A.; Ramachandran, Anup; Subramani, Sathya

    2010-01-01

    Background and Purpose: A water decoction of the poisonous shrub Cleistanthus collinus is used for suicidal purposes. The mortality rate is 28%. The clinical profile includes distal renal tubular acidosis (DRTA) and respiratory failure. The mechanism of toxicity is unclear. Objectives: To demonstrate features of C. collinus toxicity in a rat model and to identify its mechanism(s) of action. Materials and Methods: Rats were anesthetized and the carotid artery was cannulated. Electrocardiogram ...

  19. Engineering tubular bone using mesenchymal stem cell sheets and coral particles

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Wenxin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Ma, Dongyang [Department of Oral and Maxillofacial Surgery, Lanzhou General Hospital, Lanzhou Command of PLA, BinHe 333 South Road, Lanzhou 730052 (China); Yan, Xingrong; Liu, Liangqi; Cui, Jihong; Xie, Xin; Li, Hongmin [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China); Chen, Fulin, E-mail: chenfl@nwu.edu.cn [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, No.229 North Taibai Road, Xi’an 710069 (China)

    2013-04-19

    Highlights: • We developed a novel engineering strategy to solve the limitations of bone grafts. • We fabricated tubular constructs using cell sheets and coral particles. • The composite constructs showed high radiological density and compressive strength. • These characteristics were similar to those of native bone. -- Abstract: The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects.

  20. Near-Tubular Fiber Bundle Segmentation for Diffusion Weighted Imaging: Segmentation Through Frame Reorientation

    OpenAIRE

    Niethammer, Marc; Zach, Christopher; Melonakos, John; Tannenbaum, Allen

    2008-01-01

    This paper proposes a methodology to segment near-tubular fiber bundles from diffusion weighted magnetic resonance images (DW-MRI). Segmentation is simplified by locally reorienting diffusion information based on large-scale fiber bundle geometry. Segmentation is achieved through simple global statistical modeling of diffusion orientation. Utilizing a modification of a recent segmentation approach by Bresson et al. allows for a convex optimization formulation of the segmentation problem, comb...

  1. Mechanism of tubular uptake on human growth hormone in perfused rat kidneys

    International Nuclear Information System (INIS)

    The mechanism of tubular uptake of labeled human growth hormone ([125I]hGH), a low molecular weight protein (approximate 21,5000 daltons), was studied in isolated perfused rat kidneys. Fractional reabsorption (FR) of [125I]hGH was decreased from 94 to 77% over a period of 80 min as perfusate oncotic pressure was lowered by reducing the albumin concentration from 7.5 to 2.5 g/100ml, whereas greater reductions in fractional sodium (delta 35%) and fluid reabsorption (delta 42%) occurred, indicating that tubular [125I]hGH uptake is likely a specific process not directly dependent upon net fluid and sodium reabsorption. Absolute absorption rates of [125I]hGH filtered loads were inhibited by cytochalasin B, a microfilament disrupter when kidneys were perfused with either albumin concentration. Cytochalasin B inhibited [125I]hGH absorption in both a dose-and time-related manner. The low dose of cytochalasin B (2.5 micrograms/ml) decreased [125I]hGH absorption without significantly altering sodium, fluid or glucose reabsorption. With high doses (5 and 10 micrograms/ml), cytochalasin B affected tubular absorption of [125I]hGH to an extent much greater than sodium, fluid and glucose reabsorption. Inhibition of cytochalasin B on FR[125I]hGH was poorly correlated with the concurrent inhibition of FRNa and FRH2O. Accordingly, tubular reabsorption of [125I]hGH is not directly linked to that of sodium, fluid and glucose. The present studies are consistent with the hypothesis that renal absorption of low molecular-weight proteins is via an endocytotic process involving microfilaments

  2. A Pole Assignment Design Method of Process Control System for Tubular Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    周清泉

    1992-01-01

    This Paper has first studied the simplified model of tubular heat exchanger which is widely used in the industry and other field.On the basis of reference 2,a new pole assignment design method of pro-cess control system with derivative control action is found.For the above system,the method and the for-mation which calculate the feedback matrix K and gain matrix L is given,and the simulation of the system is made.

  3. Pressure-assisted forming of non-concentric tubular cross sections with solid medium

    DEFF Research Database (Denmark)

    Alves, Luis M.; Silva, Carlos M.A.; Nielsen, Chris V.;

    2016-01-01

    hydroforming) or elastomers (tube rubber forming) as pressuring medium, the subject matter of this article is centred in the utilization of low melting point, recyclable, metallic alloys as solid pressurizing medium. The aims and scope of the article are centred on the feasibility of forming straight carbon...... plastic deformation and prevent collapse can be successfully and effectively employed to fabricate non-concentric tubular cross sections for prototypes and small batches of lightweight components....

  4. Mucinous tubular and spindle cell carcinoma of the kidney associated with tuberculosis

    Directory of Open Access Journals (Sweden)

    Saloua Krichen Makni

    2011-01-01

    Full Text Available Mucinous tubular and spindle cell carcinomas (MTSCC are low-grade renal epi-thelial neoplasms with approximately 100 documented cases reported in the literature. We report a case of MTSCC in a 79-year-old patient in association with a renal tuberculosis infection that has never been reported. Further investigations are needed to determine the frequency and true prognosis of these tumors.

  5. Complications of Minimally Invasive, Tubular Access Surgery for Cervical, Thoracic, and Lumbar Surgery

    OpenAIRE

    Ross, Donald A.

    2014-01-01

    The object of the study was to review the author's large series of minimally invasive spine surgeries for complication rates. The author reviewed a personal operative database for minimally access spine surgeries done through nonexpandable tubular retractors for extradural, nonfusion procedures. Consecutive cases (n = 1231) were reviewed for complications. There were no wound infections. Durotomy occurred in 33 cases (2.7% overall or 3.4% of lumbar cases). There were no external or symptomati...

  6. Malignant phyllodes tumor with heterologous liposarcomatous differentiation and tubular adenoma-like epithelial component

    OpenAIRE

    L. Uriev, I. Maslovsky, P. Vainshtein, B. Yoffe, D. Ben-Dor

    2006-01-01

    Phyllodes tumor of the breast is a biphasic fibroepithelial neoplasm. A 30-year-old woman presented with a 1-year history of a palpable, asymptomatic right breast mass without axillary lymphadenopathy and family history of breast carcinoma. Malignant phyllodes tumor was diagnosed. The authors present not previously described histological appearance of this tumor where an epithelial component was identical to that of a tubular adenoma of the breast, with the review of the literature. This is i...

  7. Viability and fate of Cryptosporidium parvum and Giardia lamblia in tubular anaerobic digesters.

    Science.gov (United States)

    Kinyua, Maureen N; Trimmer, John; Izurieta, Ricardo; Cunningham, Jeffrey; Ergas, Sarina J

    2016-06-01

    In many developing countries where pathogenic diseases of animal waste origin, such as giardiasis and cryptosporidiosis, are often prevalent, facilities are limited to treat livestock waste. However, household-scale anaerobic digesters are currently being promoted for bioenergy production from livestock manure. Since the effluent is often used as a fertilizer for food crops, it is critical to understand the effect of environmental conditions within household-scale digesters on the viability of Cryptosporidium parvum oocysts and Giardia lamblia cysts. In this study, key environmental parameters affecting (oo)cyst inactivation were measured in four tubular anaerobic digesters, which are a type of household-scale digester promoted for treatment of swine waste in rural Costa Rica. Interviews and participant observations were used to understand digester operation and maintenance procedures. Ambient temperatures (21-24°C), near-neutral pH, total ammonia nitrogen (TAN) concentrationsparvum were 0.155 ± 0.041 and 0.054 ± 0.006 day(-1), respectively. Temperature and volatile fatty acids were the main factors contributing to Cryptosporidium parvum and Giardia lamblia inactivation. A mathematical model was developed that predicts the concentration of (oo)cysts in the liquid effluent of tubular digesters like those observed in Costa Rica. A mathematical model was developed that predicts the concentration of (oo)cysts in the liquid effluent of tubular digesters like those observed in Costa Rica. Two dimensionless groups can be used to predict the performance of the digesters for inactivating pathogens; both dimensionless groups depend upon the average HRT in the digester. This is the first study to combine mathematical modeling with qualitative analysis, field and laboratory studies to predict the concentrations of (oo)cysts in tubular digester effluents. PMID:26950630

  8. Toxicogenomic multigene biomarker for predicting the future onset of proximal tubular injury in rats

    International Nuclear Information System (INIS)

    Drug-induced renal tubular injury is a major concern in the preclinical safety evaluation of drug candidates. Toxicogenomics is now a generally accepted tool for identifying chemicals with potential safety problems. The specific aim of the present study was to develop a model for use in predicting the future onset of drug-induced proximal tubular injury following repeated dosing with various nephrotoxicants. In total, 41 nephrotoxic and nonnephrotoxic compounds were used for the present analysis. Male Sprague-Dawley rats were dosed orally or intravenously once daily. Animals were exposed to three different doses (low, middle, and high) of each compound, and kidney tissue was collected at 3, 6, 9, and 24 h after single dosing, and on days 4, 8, 15, and 29 after repeated dosing. Gene expression profiles were generated from kidney total RNA using Affymetrix DNA microarrays. Filter-type gene selection and linear classification algorithms were employed to discriminate future onset of proximal tubular injury. We identified genomic biomarkers for use in future onset prediction using the gene expression profiles determined on day 1, when most of the nephrotoxicants had yet to produce detectable histopathological changes. The model was evaluated using a five-fold cross validation, and achieved a sensitivity of 93% and selectivity of 90% with 19 probes. We also found that the prediction accuracy of the optimized model was substantially higher than that produced by any of the single genomic biomarkers or histopathology. The genes included in our model were primarily involved in DNA replication, cell cycle control, apoptosis, and responses to oxidative stress and chemical stimuli. In summary, our toxicogenomic model is particularly useful for predicting the future onset of proximal tubular injury.

  9. Styrene-maleic anhydride copolymerization in a recycle tubular reactor: reactor stability and product quality

    OpenAIRE

    Belkhiria, Sahbi; Meyer, Thierry; Renken, Albert

    1994-01-01

    A tubular recycle reactor was developed to ensure good homogeneity of concn. and temp. in the copolymn. of styrene and maleic anhydride. The compn. of the copolymer obtained is in good agreements with predicted values and the uniformity of compn. was measured for the entire mol.-wt. distribution. The characterization of the reactor (both hydrodynamic and stability) and the quality of the resulting polymer are presented herein. The limits of use of this reactor for the styrene-maleic anhydride...

  10. Flux recovery of ceramic tubular membranes fouled with whey proteins: Some aspects of membrane cleaning

    OpenAIRE

    Popović Svetlana S.; Milanović Spasenija D.; Iličić Mirela D.; Lukić Nataša Lj.; Šijački Ivana M.

    2008-01-01

    Efficiency of membrane processes is greatly affected by the flux reduction due to the deposits formation at the surface and/or in the pores of the membrane. Efficiency of membrane processes is affected by cleaning procedure applied to regenerate flux. In this work, flux recovery of ceramic tubular membranes with 50 and 200 nm pore size was investigated. The membranes were fouled with reconstituted whey solution for 1 hour. After that, the membranes were rinsed with clean water and then cleane...

  11. Simulation and design recommendations of eccentrically loaded slender concrete-filled tubular columns

    OpenAIRE

    PORTOLES FLAJ, JOSÉ MANUEL; Romero, Manuel L.; Filippou, Filip C.; Bonet Senach, José Luís

    2011-01-01

    This paper proposes an efficient numerical model for the simulation of the behavior of slender circular concrete-filled tubular columns subjected to eccentric axial load with single curvature, for the cases of both normal and high strength concrete. The paper focuses on the study of the influence that the variables affecting beam–column behavior (length and relative slenderness) and the variables affecting section behavior (diameter/thickness ratio, mechanical capacity of steel) h...

  12. Influence of ultra-high strength infill in slender concrete-filled steel tubular columns

    OpenAIRE

    PORTOLES FLAJ, JOSÉ MANUEL; Serra Mercé, Enrique; Romero, Manuel L.

    2013-01-01

    This paper describes 24 tests conducted on slender circular tubular columns filled with normal, high, and ultra-high strength concrete for plain, bar reinforced and steel fiber reinforced columns. These were reinforced and subjected to both concentric and eccentric axial load. It is a continuation of a previous research paper (Portoles et al., 2011 [1]), which presented test results on eccentrically loaded plain concrete columns. The test parameters are nominal strength of concrete (30, 90...

  13. Ambient and fire behavior of eccentrically loaded elliptical slender concrete-filled tubular columns

    OpenAIRE

    Espinós Capilla, Ana; Romero, Manuel L.; Portolés Flag, Jose Manuel; Hospitaler Pérez, Antonio

    2014-01-01

    This paper presents the results of an experimental program carried out on slender elliptical hollow section columns filled with concrete. Given the reduced number of experimental results found in the literature on concrete filled tubular columns with elliptical cross-section, the main objective of this paper is to compare the behavior of such innovative cross-sections under ambient and high temperatures. The test parameters covered in this experimental program were the load eccentricity (0, 2...

  14. Mesenchymal Stem Cell-Derived Microvesicles Protect Against Acute Tubular Injury

    OpenAIRE

    Bruno, Stefania; Grange, Cristina; Deregibus, Maria Chiara; Calogero, Raffaele A.; Saviozzi, Silvia; Collino, Federica; Morando, Laura; Busca, Alessandro; Falda, Michele; Bussolati, Benedetta; Tetta, Ciro; Camussi, Giovanni

    2009-01-01

    Administration of mesenchymal stem cells (MSCs) improves the recovery from acute kidney injury (AKI). The mechanism may involve paracrine factors promoting proliferation of surviving intrinsic epithelial cells, but these factors remain unknown. In the current study, we found that microvesicles derived from human bone marrow MSCs stimulated proliferation in vitro and conferred resistance of tubular epithelial cells to apoptosis. The biologic action of microvesicles required their CD44- and β1-...

  15. Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model.

    Directory of Open Access Journals (Sweden)

    Tokiko Ishida

    Full Text Available The pathogenesis of renal impairment in chronic liver diseases (CLDs has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy, autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet-fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the

  16. Hirsutella sinensis antagonizes the effect of aristolochic acid on human proximal tubular epithelial cells

    Institute of Scientific and Technical Information of China (English)

    张媺

    2006-01-01

    Objective To study whether Hirsutella sinensis (HS) can antagonize aristolochic acid (AA) induced fibrogenesis on human proximal tubular epithelial cells (HKC). Methods HKC were incubated with medium alone, medium with HS 10 mg/L, medium with AA-Na 40 mg/L or medium with AA-Na 40 mg/L and HS 10 mg/L, respectively. After 12 h (for mRNA) or 36 h (for protein) , cells were lysed, and the mRNA and pro-

  17. Kinetic Study on Liquid-Phase Hydrodesulfurization of FCC Diesel in Tubular Reactors

    Institute of Scientific and Technical Information of China (English)

    Li Hua; Yang Jinliang; Weng Huixin; Wang Jiming

    2015-01-01

    According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization pro-cess was developed and veriifed. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the desulfurization rate were investigated.

  18. Asymptotic analysis and numerical modeling of mass transport in tubular structures

    CERN Document Server

    Cardone, G; Sirakov, Y

    2009-01-01

    In the paper the flow in a thin tubular structure is considered. The velocity of the flow stands for a coefficient in the diffusion-convection equation set in the thin structure. An asymptotic expansion of solution is constructed. This expansion is used further for justification of an asymptotic domain decomposition strategy essentially reducing the memory and the time of the code. A numerical solution obtained by this strategy is compared to the numerical solution obtained by a direct FEM computation.

  19. Renal tubular dysfunction in pediatric patients with beta-thalassemia major

    Directory of Open Access Journals (Sweden)

    Ali Ahmadzadeh

    2011-01-01

    Full Text Available To evaluate the prevalence of renal tubular dysfunction in children with β-thalassemia (β-T major, we studied the glomerular and tubular function in 140 children with β-T major and compared them to a healthy control group at our center from May 2007 to April 2008. Fresh first morning samples were collected from each patient and analyzed for sodium, potassium, calcium (Ca, protein, uric acid (UA, creatinine (Cr, urine osmolality and urinary N-acetyl-β-D-glucosaminidase (UNAG activity. Blood samples were also collected for complete blood count, blood urea nitrogen (BUN, fasting blood sugar, serum creatinine (SCr, electrolytes, and ferritin before transfusion. Among the study patients, 72 were males, and the mean age was 11.5 (ranging 7-16 years. SCr levels were all within normal limits and all of them had normal glomerular filtration rate (GFR. The mean UNAG was 17.8 IU/L in the study patients (normal 0.15-11.5 IU/L and 3.2 IU/L in the control group (P 0.21 (P = 0.006. Nine (6.4% thalassemic patients with a mean age of 12 years had proteinuria (Upr/UCr > 0.2. Sixty-nine (49.3% out of the 140 patients and 45 (65.2% of the patients having UNAG had uricosuria also (UUA/UCr > 0.26. Ten (7% patients had microscopic hematuria and 10 (7% patients with a mean age of 13.5 years had glucosuria or diabetes mellitus. We conclude that tubular dysfunction is a relative common complication of the β-T major; UNAG and its index are the best to detect renal tubular dysfunction in these patients. Currently, periodic measurement of UCa/UCr and UUA/UCr ratios as well as urinalysis are recommended.

  20. Spinning Deformation Criteria of Thin-walled Tubular Part with Longitudinal Inner Ribs

    Institute of Scientific and Technical Information of China (English)

    JIANG Shuyong; XUE Kemin; LI Chunfeng; REN Zhengyi

    2006-01-01

    As a successive and local plastic delormation process, backward ball spinning was applied for the purpose of producing thin-walled tubular parts with longitudinal inner ribs. According to the local plastic deformation theory, the application of yield criterion to the spinning process and the influence of the radial spinning force component on the formability of inner ribs were analyzed. Based on yield criterion and plastic mechanics, the stable flow rude of metal material and forming criteria of the inner ribs were obtained and conformed to the experimental results so as to contribute greatly to improving the ball spinning process and optimizing the process variables, such as the diameter of ball, the reduction in a pass and the wall thickness of tubular blank, which have a significant influence on the formability of the inner ribs. The knowledge of the influence of the process variables such as the diameter of ball, the reduction in a pass and the wall thickness of tubular blank on the spinning process is essential to preventing the quality defects of the spun parts and obtaining the desired spun parts.

  1. Novel Tubular Biomarkers Predict Renal Progression in Type 2 Diabetes Mellitus: A Prospective Cohort Study

    Science.gov (United States)

    Aramsaowapak, Kasemsan; Tangwonglert, Theerasak; Supasyndh, Ouppatham

    2016-01-01

    Background. Tubulointerstitial injury is both a key feature of diabetic nephropathy and an important predictor of renal dysfunction. Novel tubular biomarkers related to renal injury in diabetic nephropathy could improve risk stratification and prediction. Methods. A total of 303 type 2 diabetic patients were followed up. The baseline urine values of cystatin-C to creatinine ratio (UCCR), angiotensinogen to creatinine ratio (UANG), NGAL to creatinine ratio (UNGAL), and KIM-1 to creatinine ratio (UKIM-1) were measured. The primary outcome was a decline in estimated GFR of ≥25% yearly from baseline. Results. Urine tubular biomarkers of UCCR, UANG, UNGAL, and UKIM-1 were significantly higher according to the degree of albuminuria and all were significantly higher among patients with rapid decline in estimated GFR of ≥25% yearly from baseline. All biomarkers predicted primary outcomes with ROC for UCCR of 0.72; 95% CI 0.64–0.79, for UANG of 0.71; 95% CI 0.63–0.79, for UNGAL of 0.64; 95% CI 0.56–0.72, and for UKIM-1 of 0.71; 95% CI 0.63–0.79. Using multivariate Cox regression analysis, the number of patients with rapid renal progression was higher among those in the upper quartiles of all biomarkers than in those in the lower quartiles. Conclusions. Type 2 diabetic patients with high levels of urine tubular biomarkers had a more rapid decline in renal function. PMID:27672664

  2. Tubular immunostimulating complex based on cucumarioside A2-2 and monogalactosyldiacylglycerol from marine macrophytes

    Directory of Open Access Journals (Sweden)

    Vorobyeva Natalia S

    2011-09-01

    Full Text Available Abstract Background There is an urgent need to develop safe and effective adjuvants for the new generation of subunit vaccines. We developed the tubular immunostimulating complex (TI-complex as a new nanoparticulate antigen delivery system. The morphology and composition of TI-complexes principally differ from the known vesicular immunostimulating complexes (ISCOMs. However, methodology for the preparation of TI-complexes has suffered a number of shortcomings. The aim of the present work was to obtain an antigen carrier consisting of triterpene glycosides from Cucumaria japonica, cholesterol, and monogalactosyldiacylglycerol from marine macrophytes with reproducible properties and high adjuvant activity. Results The cucumarioside A2-2 - cholesterol - MGalDG ratio of 6:2:4 (by weight was found to provide the most effective formation of TI-complexes and the minimum hemolytic activity in vitro. Tubules of TI-complexes have an outer diameter of about 16 nm, an inner diameter of 6 nm, and a length of 500 nm. A significant dilution by the buffer gradually destroyed the tubular nanoparticles. The TI-complex was able to increase the immunogenicity of the protein antigens from Yersinia pseudotuberculosis by three to four times. Conclusions We propose an optimized methodology for the preparation of homogeneous TI-complexes containing only tubular particles, which would achieve reproducible immunization results. We suggest that the elaborated TI-complexes apply as a universal delivery system for different subunit antigens within anti-infectious vaccines and enhance their economic efficacy and safety.

  3. Investigations of turbulent flows in a tubular pump and structural stresses of its impeller

    International Nuclear Information System (INIS)

    Based on Navier-Stokes equations and RNG k-ε turbulence model, numerical simulation was carried out to investigate turbulent flows in tubular pumps and structural stresses of its impeller using commercial software of ANSYS Workbench. Firstly, the calculated velocity and pressure distributions in tubular pumps show that the whole flow pattern is uniform except for that in the region in the front of the pier in the discharge passage. The predicted spiral streamlines in the front of the discharge passage indicate that there exists an unrecovered velocity circulation. The computed reasonable distributions of the static pressure show the minimum happens at inlet edges on the suction surfaces of the blades which probably causes cavitations. One-way fluid-structure interaction method was then employed to make a further static structural analysis of the impeller, and the predicted stresses and deformations of the blades show that the maximal equivalent stress exists in the joint between the blades and the hub on pressure surfaces of the impeller, the maximum of total deformations of the blades increases as the radius increases. The maximal exists near the impeller rim at the inlet and outlet edges. The calculated results will provide references for further design and research of tubular pumps.

  4. Long-term observations on tubular and glomerular function in cadmium-exposed persons

    Energy Technology Data Exchange (ETDEWEB)

    Piscator, M.

    1984-03-01

    Four groups of cadmium-exposed persons, from different workplaces and with different types of exposure, have been followed for periods of 9-20 years. In one group the total observation time is over 30 years, since they were included in Friberg's original study. The studies include determination of inulin or creatinine clearance, protein excretion and specific indicators of renal tubular dysfunction. The results indicate that once tubular dysfunction is established, it is irreversible, even when it is minor. In some persons it was noted that the development of renal dysfunction seemed to be a multistage process. The initial stage is characterized by an increased excretion of low molecular weight proteins like ..beta../sub 2/-microglobulin and ribonuclease. After a period of several years with no or low exposure, there was a relatively sharp increase in excretion of total proteins and albumin and a decrease in glomerular filtration rate. This is interpreted as being the result of further increases in renal concentration of cadmium and in spread of cadmium along the tubules. Metallothionein absorption in the tubules, its catabolism and synthesis must play an important role for the development and progress of the tubular dysfunction. It was not possible to show that a decrease in glomerular filtration rate occurs before low molecular weight proteinuria. 15 references, 2 figures, 2 tables.

  5. Experimental investigations and modeling of direct internal reforming of biogases in tubular solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lanzini, A.; Leone, P.; Pieroni, M.; Santarelli, M. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129, Torino (Italy); Beretta, D.; Ginocchio, S. [Centro Ricerca e Sviluppo, Edison S.p.a, Via La Pira 2, IT-10028 Trofarello, Torino (Italy)

    2011-10-15

    Biogas-fed Solid Oxide Fuel Cell (SOFC) systems can be considered as interesting integrated systems in the framework of distributed power generation. In particular, bio-methane and bio-hydrogen produced from anaerobic digestion of organic wastes represent renewable carbon-neutral fuels for high efficiency electrochemical generators. With such non-conventional mixtures fed to the anode of the SOFC, the interest lies in understanding the multi-physics phenomena there occurring and optimizing the geometric and operation parameters of the SOFC, while avoiding operating and fuel conditions that can lead to or accelerate degradation processes. In this study, an anode-supported (Ni-YSZ) tubular SOFC was considered; the tubular geometry enables a relatively easy separation of the air and fuel reactants and it allows one to evaluate the temperature field of the fuel gas inside the tube, which is strictly related to the electrochemical and heterogeneous chemical reactions occurring within the anode volume. The experiments have been designed to analyze the behavior of the cell under different load and fuel utilization (FU) conditions, providing efficiency maps for both fuels. The experimental results were used to validate a multi-physics model of the tubular cell. The model showed to be in good agreement with the experimental data, and was used to study the sensitive of some selected geometrical parameters modification over the cell performances. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. The use of lithium clearance measurements as an estimate of glomerulo-tubular function.

    Science.gov (United States)

    Whiting, P H

    1999-01-01

    Lithium clearance measurements are based on the observation that lithium undergoes isoosmotic reabsorption in the proximal renal tubule to the same extent as salt and water, but undergoes neither reabsorption nor secretion elsewhere in the nephron. Consequently, lithium clearance values estimate the delivery of isoosmotic fluid to the loop of Henle and hence provide an assessment of proximal tubular reabsorption of isoosmotic fluid. If sodium clearance and urinary flow rate are also measured, then this allows the derivation of a number of parameters relating to both the absolute and relative renal handling of isoosmotic fluid in the proximal and distal regions of the kidney. Consequently, lithium clearance techniques can be used in both experimental and clinical studies to evaluate glomerulo-tubular function and provide information regarding the handling of sodium and water by the proximal and distal nephron in both health and disease. The use of lithium clearance measurements in the assessment of glomerulo-tubular function in patients treated with rIL2 for colorectal cancer is described and its application to both drug-induced toxicity and other disease states discussed.

  7. Power Generation and Peltier Refrigeration by a Tubular π-Type Thermoelectric Module

    Science.gov (United States)

    Sakai, Akihiro; Kanno, Tsutomu; Takahashi, Kouhei; Tamaki, Hiromasa; Yamada, Yuka

    2015-11-01

    A tubular configuration is a practical form of thermoelectric (TE) device to generate electric power from fluid heat sources as well as to control the temperature of fluid media by Peltier effect. Here, we report the realization of a tubular π-type TE module which enables both power generation and Peltier refrigeration. The tubular module was obtained by stacking ring-shaped constituents in the axial direction, followed by simultaneous spark plasma sintering and joining processes. The experimentally-observed maximum power-density and efficiency are 0.9 kW/m2 and 2.2%, respectively, when a small temperature difference (Δ T) of 85 K was maintained using hot and cold water. Peltier refrigeration of the tube outer surface is also demonstrated. The obtained maximum Δ T and the cooling power density are Δ T = 49 K and 32.6 kW/m2, respectively. The present results indicate the high feasibility of this tube as a fluid-mediated practical TE module.

  8. Geometric optimization of a solar cubic-cavity multi-tubular reactor

    Science.gov (United States)

    Valades-Pelayo, P. J.; Arancibia-Bulnes, C. A.; Villafan-Vidales, H.; Romero-Paredes, H.

    2016-05-01

    A multi-tubular solar thermochemical cavity reactor is proposed and the tubular array optimized. The optimized reactor design aims at operating under different temperatures and carrying out different kinds of thermochemical reactions. The radiation entering the receptacle comes from a solar concentrating system and the reactor consists of a cubic receptacle made of woven graphite, housing nine 2.54 cm diameter tungsten tubes. A model is developed and implemented considering high-temperature radiative transfer at steady state. The temperature distribution within the cavity surfaces is determined by employing a hybrid Monte Carlo-Finite Volume approach. Optimal tube distributions are explored by using a custom-made stochastic, multi-parameter, optimization algorithm. In this way, multiple global maxima are determined. Patterns among all possible optimal tube distributions within the cavity are obtained for different scenarios, by maximizing average tube temperature. From this study, practical guidelines are obtained for future application in the design of solar cavity reactors and more specifically, on the layout of multi tubular arrays to optimize radiative heat transfer.

  9. The swan-neck lesion: proximal tubular adaptation to oxidative stress in nephropathic cystinosis.

    Science.gov (United States)

    Galarreta, Carolina I; Forbes, Michael S; Thornhill, Barbara A; Antignac, Corinne; Gubler, Marie-Claire; Nevo, Nathalie; Murphy, Michael P; Chevalier, Robert L

    2015-05-15

    Cystinosis is an inherited disorder resulting from a mutation in the CTNS gene, causing progressive proximal tubular cell flattening, the so-called swan-neck lesion (SNL), and eventual renal failure. To determine the role of oxidative stress in cystinosis, histologic sections of kidneys from C57BL/6 Ctns(-/-) and wild-type mice were examined by immunohistochemistry and morphometry from 1 wk to 20 mo of age. Additional mice were treated from 1 to 6 mo with vehicle or mitoquinone (MitoQ), an antioxidant targeted to mitochondria. The leading edge of the SNL lost mitochondria and superoxide production, and became surrounded by a thickened tubular basement membrane. Progression of the SNL as determined by staining with lectin from Lotus tetragonolobus accelerated after 3 mo, but was delayed by treatment with MitoQ (38 ± 4% vs. 28 ± 1%, P injury molecule-1 (KIM-1) nor cell death was observed. After 9 mo, clusters of proximal tubules exhibited localized oxidative stress (4-hydroxynonenal binding), expressed KIM-1, and underwent apoptosis, leading to the formation of atubular glomeruli and accumulation of interstitial collagen. We conclude that nephron integrity is initially maintained in the Ctns(-/-) mouse by adaptive flattening of cells of the SNL through loss of mitochondria, upregulation of transgelin, and thickened basement membrane. This adaptation ultimately fails in adulthood, with proximal tubular disruption, formation of atubular glomeruli, and renal failure. Antioxidant treatment targeted to mitochondria delays initiation of the SNL, and may provide therapeutic benefit in children with cystinosis. PMID:25694483

  10. Role of Connective Tissue Growth Factor in Extracellular Matrix Degradation in Renal Tubular Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun; ZHU Zhonghua; LIU Jianshe; YANG Xiao; FU Ling; DENG Anguo

    2007-01-01

    In order to investigate the effects of connective tissue growth factor (CTGF) antisense oligodeoxynucleotide (ODN) on plasminogen activator inhibitor-1 (PAI-1) expression in renal tubular cells induced by transforming growth factor β1 (TGF-β1) and to explore the role of CTGF in the degradation of renal extracellular matrix (ECM), a human proximal tubular epithelial cell line (HKC) was cultured in vitro. Cationic lipid-mediated CTGF antisense ODN was transfected into HKC. After HKC were stimulated with TGF-β1 (5 μg/L), the mRNA level of PAI-1 was detected by RT-PCR. Intracellular PAI-1 protein synthesis was assessed by flow cytometry. The secreted PAI-1 in the media was determined by Western blot. The results showed that TGF-β1 could induce tubular CTGF and PAI-1 mRNA expression. The PAI-1 mRNA expression induced by TGF-β1 was significantly inhibited by CTGF antisense ODN. CTGF antisense ODN also inhibited intracellular PAI-1 protein synthesis and lowered the levels of PAI-1 protein secreted into the media. It was concluded that CTGF might play a crucial role in the degradation of excessive ECM during tubulointerstitial fibrosis, and blocking the biological effect of CTGF may be a novel way in preventing renal fibrosis.

  11. Tubular foreign body or stent: safe retrieval or repositioning using the coaxial snare technique

    International Nuclear Information System (INIS)

    To evaluate the utility and advantages of the coaxial snare technique in the retrieval of tubular foreign bodies. Using the coaxial snare technique, we attempted to retrieve tubular foreign bodies present in seven patients. The bodies were either stents which were malpositioned or had migrated from their correct position in the vascular system (n=2), a fragmented venous introducer sheath (n=1), fragmented drainage catheters in the biliary tree (n=2), or fractured external drainage catheters in the urinary tract (n=2). After passing a guidewire and/or a dilator through the lumina of these foreign bodies, we introduced a loop snare over the guidewire or dilator, thus capturing and retrieving them. In all cases, it was possible to retrieve or reposition the various items, using a minimum-sized introducer sheath or a tract. No folding was involved. In no case were surgical procedures required, and no complications were encountered. The coaxial snare technique, an application of the loop snare technique, is a useful and safe method for the retrieval of tubular foreign bodies, and one which involves minimal injury to the patient

  12. A Mathematical Model of Renal Blood Distribution Coupling TGF, MR and Tubular System

    Institute of Scientific and Technical Information of China (English)

    GAO Ci-xiu; YANG Lin; WANG Ke-qiang; XU Shi-xiong; DAI Pei-dong

    2009-01-01

    Objective:To investigate the relationship between renal blood distribution and the physiological activities of the kidney. Methods:A mathematical model is developed based on Hagan-Poiseuille law and mass transport, coupling mechanics of myogenic response (MR), tubuloglomerular feedback (TGF) and the tubular system in the renal medulla. The model parameters, including the permeability coefficients, the vascular lumen radius and the solute concentration at the inlet of the tubes, are derived from the experimental results. Simulations of the blood and water flow in the loop of Henel, the collecting duct and vas rectum, are carried out by the model of the tubular system in the renal medulla, based on conservations of water and solutes for transmural transport. Then the tubular model is coupled with MR and TGF mechanics. Results:The results predict the dynamics of renal autoregulation on its blood pressure and flow,and the distributions are 88.5% in the cortex, 10.3% in the medulla, and 1.2% at papilla,respectively. The fluid flow and solute concentrations along the tubules and vasa recta are obtained. Conclusion:The present model could assess renal functions qualitatively and quantitatively and provide a methodological approach for clinical research.

  13. Fabrication and characterization of an all-diamond tubular flow microelectrode for electroanalysis.

    Science.gov (United States)

    Hutton, Laura A; Vidotti, Marcio; Iacobini, James G; Kelly, Chris; Newton, Mark E; Unwin, Patrick R; Macpherson, Julie V

    2011-07-15

    The development of the first all-diamond hydrodynamic flow device for electroanalytical applications is described. Here alternate layers of intrinsic (insulating), conducting (heavily boron doped), and intrinsic polycrystalline diamond are grown to create a sandwich structure. By laser cutting a hole through the material, it is possible to produce a tubular flow ring electrode of a characteristic length defined by the thickness of the conducting layer (for these studies ∼90 μm). The inside of the tube can be polished to 17 ± 10 nm surface roughness using a diamond impregnanted wire resulting in a coplanar, smooth, all-diamond surface. The steady-state limiting current versus volume flow rate characteristics for the one electron oxidation of FcTMA(+) are in agreement with those expected for laminar flow in a tubular electrode geometry. For dopamine detection, it is shown that the combination of the reduced fouling properties of boron doped diamond, coupled with the flow geometry design where the products of electrolysis are washed away downstream of the electrode, completely eradicates fouling during electrolysis. This paves the way for incorporation of this flow design into online electroanalytical detection systems. Finally, the all diamond tubular flow electrode system described here provides a platform for future developments including the development of ultrathin ring electrodes, multiple apertures for increased current response, and multiple, individually addressable ring electrodes incorporated into the same flow tube.

  14. Cisplatin nephrotoxicity involves mitochondrial injury with impaired tubular mitochondrial enzyme activity.

    Science.gov (United States)

    Zsengellér, Zsuzsanna K; Ellezian, Lena; Brown, Dan; Horváth, Béla; Mukhopadhyay, Partha; Kalyanaraman, Balaraman; Parikh, Samir M; Karumanchi, S Ananth; Stillman, Isaac E; Pacher, Pál

    2012-07-01

    Cisplatin is a widely used antineoplastic agent. However, its major limitation is dose-dependent nephrotoxicity whose precise mechanism is poorly understood. Recent studies have suggested that mitochondrial dysfunction in tubular epithelium contributes to cisplatin-induced nephrotoxicity. Here the authors extend those findings by describing the role of an important electron transport chain enzyme, cytochrome c oxidase (COX). Immunohistochemistry for COX 1 protein demonstrated that, in response to cisplatin, expression was mostly maintained in focally damaged tubular epithelium. In contrast, COX enzyme activity in proximal tubules (by light microscopy) was decreased. Ultrastructural analysis of the cortex and outer stripe of the outer medulla showed decreased mitochondrial mass, disruption of cristae, and extensive mitochondrial swelling in proximal tubular epithelium. Functional electron microscopy showed that COX enzyme activity was decreased in the remaining mitochondria in the proximal tubules but maintained in distal tubules. In summary, cisplatin-induced nephrotoxicity is associated with structural and functional damage to the mitochondria. More broadly, using functional electron microscopy to measure mitochondrial enzyme activity may generate mechanistic insights across a spectrum of renal disorders. PMID:22511597

  15. Thalidomide Ameliorates Inflammation and Vascular Injury but Aggravates Tubular Damage in the Irradiated Mouse Kidney

    Energy Technology Data Exchange (ETDEWEB)

    Scharpfenecker, Marion, E-mail: m.scharpfenecker@nki.nl [Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam (Netherlands); Floot, Ben [Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam (Netherlands); Russell, Nicola S. [Division of Radiotherapy, The Netherlands Cancer Institute, Amsterdam (Netherlands); Coppes, Rob P. [Departments of Radiation Oncology and Cell Biology, University Medical Centre Groningen, University of Groningen, Groningen (Netherlands); Stewart, Fiona A. [Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam (Netherlands)

    2014-07-01

    Purpose: The late side effects of kidney irradiation include vascular damage and fibrosis, which are promoted by an irradiation-induced inflammatory response. We therefore treated kidney-irradiated mice with the anti-inflammatory and angiogenesis-modulating drug thalidomide in an attempt to prevent the development of late normal tissue damage and radiation nephropathy in the mouse kidney. Methods and Materials: Kidneys of C57Bl/6 mice were irradiated with a single dose of 14 Gy. Starting from week 16 after irradiation, the mice were fed with thalidomide-containing chow (100 mg/kg body weight/day). Gene expression and kidney histology were analyzed at 40 weeks and blood samples at 10, 20, 30, and 40 weeks after irradiation. Results: Thalidomide improved the vascular structure and vessel perfusion after irradiation, associated with a normalization of pericyte coverage. The drug also reduced infiltration of inflammatory cells but could not suppress the development of fibrosis. Irradiation-induced changes in hematocrit and blood urea nitrogen levels were not rescued by thalidomide. Moreover, thalidomide worsened tubular damage after irradiation and also negatively affected basal tubular function. Conclusions: Thalidomide improved the inflammatory and vascular side effects of kidney irradiation but could not reverse tubular toxicity, which probably prevented preservation of kidney function.

  16. Process factors influencing spinning deformation of thin-walled tubular part with longitudinal inner ribs

    Institute of Scientific and Technical Information of China (English)

    江树勇; 薛克敏; 宗影影; 喻林

    2004-01-01

    As a successively and locally plastic deformation process, ball backward spinning is applied for the purpose of producing thin-walled tubular parts with longitudinal inner ribs. By simplifying ball backward spinning as forward extrusion mechanics model, slab method is used in order to solve spinning force. Based on plastic mechanics, the influence of the process parameters involved on formability of inner ribs as well as the quality defects of spun parts is analyzed so as to present an approach to acquire the desired parts. The quality of inner ribs is one of the critical tasks in obtaining the desired spun workpieces and the height of inner rib depends greatly on spinning material,ball diameter, feed ratio, and wall thickness of tubular blank. The knowledge of the influence of process variables such as ball diameter, feed ratio, and wall thickness of tubular blank on the spinning process is essential to prevent the quality defects of the spun parts and obtain the desired spun parts.

  17. A Tubular Biomaterial Construct Exhibiting a Negative Poisson’s Ratio

    Science.gov (United States)

    Lee, Jin Woo; Soman, Pranav; Park, Jeong Hun; Chen, Shaochen; Cho, Dong-Woo

    2016-01-01

    Developing functional small-diameter vascular grafts is an important objective in tissue engineering research. In this study, we address the problem of compliance mismatch by designing and developing a 3D tubular construct that has a negative Poisson’s ratio νxy (NPR). NPR constructs have the unique ability to expand transversely when pulled axially, thereby resulting in a highly-compliant tubular construct. In this work, we used projection stereolithography to 3D-print a planar NPR sheet composed of photosensitive poly(ethylene) glycol diacrylate biomaterial. We used a step-lithography exposure and a stitch process to scale up the projection printing process, and used the cut-missing rib unit design to develop a centimeter-scale NPR sheet, which was rolled up to form a tubular construct. The constructs had Poisson’s ratios of -0.6 ≤ νxy ≤ -0.1. The NPR construct also supports higher cellular adhesion than does the construct that has positive νxy. Our NPR design offers a significant advance in the development of highly-compliant vascular grafts. PMID:27232181

  18. Minimally invasive posterior cervical decompression using tubular retractor: The technical note and early clinical outcome

    Directory of Open Access Journals (Sweden)

    Jung-Woo Hur

    2014-01-01

    Full Text Available Background: The aim of this work is to present a novel decompression technique that approaches cervical spine posteriorly, but through minimal invasive method using tubular retractor avoiding detachment of posterior musculature. Methods: Six patients underwent minimally invasive posterior cervical decompression using the tubular retractor system and surgical microscope. Minimally invasive access to the posterior cervical spine was performed with exposure through a paramedian muscle-splitting approach. With the assistance of a specialized tubular retraction system and deep soft tissue expansion mechanism, multilevel posterior cervical decompression could be accomplished. This approach also allows safe docking of the retractor system on the lateral mass, thus avoiding the cervical spinal canal during exposure. A standard operating microscope was used with ×10 magnification and 400 mm focal length. The hospital charts, magnetic resonance imaging studies, and follow-up records of all the patients were reviewed. Outcome was assessed by neurological status and visual analog scale (VAS for neck and arm pain. Results: There was no significant complication related to operation. The follow-up time was 4-12 months (mean, 9 months. Muscle weakness improved in all patients; sensory deficits resolved in four patients and improved in two patients. Analysis of the mean VAS for radicular pain and VAS for neck pain showed significant improvement. Conclusions: The preliminary experiences with good clinical outcome seem to promise that this minimally invasive technique is a valid alternative option for the treatment of cervical spondylotic myelopathy.

  19. Application of pH control to a tubular flow reactor

    Institute of Scientific and Technical Information of China (English)

    Halil Vural; Ayla Altinten; Hale Hapolu; Sebahat Erdoan; Mustafa Alpbaz

    2015-01-01

    Tubular flow reactors are mainly used in chemical industry and waste water discharged units. Control of output variables is very difficult because of the existence of high dead-time in these types of reactors. In the present work, sodium hydroxide and acetic acid solutions were sent to the tubular flow reactor. The aim was to control pH at 7 in the nonlinear region. The pH control of a tubular flow reactor with high time delay and a highly nonlinear behavior in pH neutralization reaction was investigated experimentally in the face of the various load and set point changes. Firstly, efficiency of conventional Proportional-Integral-Derivative (PID) algorithm in the experiments was tested. Then self-tuning PID (STPID) control system was applied by using the ARMAX model. The model parameters were calculated from input–output data by using PRBS signal as disturbance and Bierman algorithm. Lastly, the experimental fuzzy control of pH based on fuzzy model was achieved to compare the success of fuzzy approach with the performance of other control cases studied.

  20. Transverse writing of three-dimensional tubular optical waveguides in glass with slit-shaped femtosecond laser beams

    CERN Document Server

    Liao, Yang; Wang, Peng; Chu, Wei; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-01-01

    We report on fabrication of tubular optical waveguides buried in ZBLAN glass based on transverse femtosecond laser direct writing. Irradiation in ZBLAN with focused femtosecond laser pulses leads to decrease of refractive index in the modified region. Tubular optical waveguides of variable mode areas are fabricated by forming the four sides of the cladding with slit-shaped femtosecond laser pulses, ensuring single mode waveguiding with a mode field dimension compatible with direct coupling to single-mode optical fibers.

  1. Hierarchical tubular structures constructed by carbon-coated SnO(2) nanoplates for highly reversible lithium storage.

    Science.gov (United States)

    Zhang, Lei; Zhang, Genqiang; Wu, Hao Bin; Yu, Le; Lou, Xiong Wen David

    2013-05-14

    Hierarchical tubular structures constructed by ultrathin carbon-coated SnO(2) nanoplates are rationally designed and synthesized. This interesting structure simultaneously integrates the structural and compositional design rationales for high-energy anode materials based on low-dimensional ultrathin nanoplates, a hollow tubular structure, and a carbon nanocoating. When evaluated as an anode material for lithium-ion batteries, the as-synthesized SnO(2)-carbon hybrid structure manifests high specific capacity and excellent cycling stability. PMID:23553828

  2. Transverse writing of three-dimensional tubular optical waveguides in glass with a slit-shaped femtosecond laser beam

    Science.gov (United States)

    Liao, Yang; Qi, Jia; Wang, Peng; Chu, Wei; Wang, Zhaohui; Qiao, Lingling; Cheng, Ya

    2016-01-01

    We report on fabrication of tubular optical waveguides buried in ZBLAN glass based on transverse femtosecond laser direct writing. Irradiation in ZBLAN with focused femtosecond laser pulses leads to decrease of refractive index in the modified region. Tubular optical waveguides of variable mode areas are fabricated by forming the four sides of the cladding with slit-shaped femtosecond laser pulses, ensuring single mode waveguiding with a mode field dimension as small as ~4 μm. PMID:27346285

  3. RIPK3-Mediated Necroptosis and Apoptosis Contributes to Renal Tubular Cell Progressive Loss and Chronic Kidney Disease Progression in Rats.

    Science.gov (United States)

    Zhu, Yongjun; Cui, Hongwang; Xia, Yunfeng; Gan, Hua

    2016-01-01

    Tubulointerstitial fibrosis (TIF) is caused by the progressive loss of renal tubular cells and the consequent replacement of the extracellular matrix. The progressive depletion of renal tubular cells results from apoptosis and necroptosis; however, the relative significance of each of these cell death mechanisms at different stages during the progression of chronic kidney disease (CKD) remains unclear. We sought to explore the mechanisms of renal tubular cell death during the early and intermediate stages of chronic renal damage of subtotal nephrectomied (SNx) rats. The results of tissue histological assays indicated that the numbers of necrotic dying cells and apoptotic cells were significantly higher in kidney tissues derived from a rat model of CKD. In addition, there was a significant increase in necroptosis observed by transmission electron microscopy (TEM) and an increase in the proportion of TUNEL-positive cells in kidney tissues from SNx rats compared with control rats, and necrostatin-1 (Nec-1) could inhibit necroptosis and reduce the proportion of TUNEL-positive cells. More importantly, we observed a significant increase in the incidence of necroptosis compared with apoptosis by TEM in vivo and in vitro and a significant increase in the proportion of TUNEL-positive tubular epithelial cells that did not express caspase-3 compared with those expressing cleaved caspase-3 in vitro. Furthermore, treatment with Nec-1 and zVAD strongly reduced necroptosis- and apoptosis-mediated renal tubular cell death and decreased the levels of blood urea nitrogen and serum creatinine and tubular damage scores of SNx rats. These results suggest that necroptotic cell death plays a more significant role than apoptosis in mediating the loss of renal tubular cells in SNx rats and that effectively blocking both necroptosis and apoptosis improves renal function and tubular damage at early and intermediate stages of CKD.

  4. Incorporation of statistical distribution of particle properties in chemical reactor design and operation: the cooled tubular reactor

    OpenAIRE

    Wijngaarden, R.J.; Westerterp, K.R.

    1992-01-01

    Pellet heat and mass transfer coefficients inside packed beds do not have definite deterministic values, but are stochastic quantities with a certain distribution. Here, a method is presented to incorporate the stochastic distribution of pellet properties in reactor design and operation models. The theory presented is illustrated with a number of examples. It is shown that pellet-scale statistics have an impact on cooled tubular reactor design and operation. Cooled tubular reactor design is d...

  5. Model to predict shrinkage and ejection forces of injection moulded tubular parts of short glass fiber reinforced thermoplastics

    OpenAIRE

    Garcia, M. C. R.; Netto, A. C. S.; Pontes, A. J.

    2011-01-01

    This work presents a model to predict shrinkage and ejection forces for glass fiber reinforced thermoplastics of tubular geometry. This mathematical model was based in Jansen’s Model to predict shrinkage and residual stresses in fiber reinforced injection molded products and Pontes’s Model to predict ejection forces for tubular parts of pure PP. The model used the modified classical laminate theory applied to injection moulding and it uses the fiber orientation state, temperatu...

  6. Preparação e caracterização de membranas cerâmicas tubulares de mulita

    Directory of Open Access Journals (Sweden)

    F. A. Silva

    2013-09-01

    Full Text Available Os produtos cerâmicos são extremamente interessantes no campo das membranas por causa de sua resistência mecânica, inércia química, tempo de vida útil longa e estabilidade térmica. Atualmente as pesquisas estão sendo direcionadas para exploração destes materiais de baixo custo. Este trabalho consiste na preparação de membranas tubulares, obtidas a partir de composição contendo argila, caulim e óxido de alumínio, conformadas pelo processo de extrusão, utilizando diferentes temperaturas na etapa de sinterização para uso em microfiltração. Foi feita caracterização nas massas cerâmicas antes da sinterização, através dos ensaios de análise granulométrica, análise termogravimétrica, análise química e difração de raios X. A análise química mostrou altos teores de SiO2 e de Al2O3 e o ensaio de difração de raios X mostrou a presença de caulinita, quartzo e óxido de alumínio. Foi realizado ensaio de difração de raios X na massa após as sinterizações e os resultados mostraram a presença de mulita, óxido de alumínio e quartzo em todas as sinterizações efetuadas. Com relação ao tamanho e a distribuição destes poros nas membranas, os resultados da micrografia e de porosimetria por intrusão de mercúrio ilustraram a presença de poros em todas as temperaturas de sinterização, com dimensões na faixa de microfiltração. O ensaio de fluxo com escoamento tangencial utilizando água destilada mostrou que a membrana sinterizada a 1300 ºC obteve o maior valor, seguida da de 1250, 1200 e 1150 ºC.

  7. Transmission Characteristics in Tubular Acoustic Metamaterials Studied with Fluid Impedance Theory

    Institute of Scientific and Technical Information of China (English)

    FAN Li; ZHANG Shu-Yi; ZHANG Hui

    2011-01-01

    Tubular acoustic metamaterials with negative densities composed of periodical membranes set up along pipes are studied with the fluid impedance theory. In addition to the conventional forbidden bands induced by the Bragg-scattering due to the periodic distributions of different acoustic impedances, the low-frequency forbidden band (LFB) with the low-frequency limit of zero Hertz is studied, in which the LFB is explained with acoustic impedance matching and the Bloch theory. Furthermore, the influences of the structural parameters of the tubular acoustic metamaterials on the transmission characteristics, such as the transmission coefficients, dispersion curves, widths of forbidden and pass bands, fluctuations in pass bands, etc., are evaluated, which can be used in the optimization of the acoustic insulation ability of the metamaterials.%Tubular acoustic metamaterials with negative densities composed of periodical membranes set up along pipes are studied with the fluid impedance theory.In addition to the conventional forbidden bands induced by the Bragg-scattering due to the periodic distributions of different acoustic impedances,the low-frequency forbidden band (LFB) with the low-frequency limit of zero Hertz is studied,in which the LFB is explained with acoustic impedance matching and the Bloch theory.Furthermore,the influences of the structural parameters of the tubular acoustic metamaterials on the transmission characteristics,such as the transmission coefficients,dispersion curves,widths of forbidden and pass bands,fluctuations in pass bands,etc.,are evaluated,which can be used in the optimization of the acoustic insulation ability of the metamaterials.Like electromagnetic metamaterials,acoustic metamaterials have been presented with different structures,which have negative constitutive parameters of acoustic propagation and can realize unique acoustic characteristics and applications.[1-5] Recently,acoustic metamaterials were introduced into acoustic resonance

  8. Myoglobin inhibits proliferation of cultured human proximal tubular (HK-2) cells.

    Science.gov (United States)

    Iwata, M; Zager, R A

    1996-09-01

    Following nephrotoxic injury, renal repair is dependent on tubular regeneration. In the case of myoglobinuric acute renal failure (ARF), persistence of myoglobin within tubular cells, or sublethal injury sustained at the height of exposure to it, might retard this process. To test this hypothesis, a human proximal tubular cell line (HK-2) was cultured for 24 hours in the absence or presence of clinically relevant myoglobin concentrations (0.5, 1, 2, 4 mg/ml). Immediately following myoglobin removal, lethal cell injury (vital dye uptake), lipid peroxidation, and DNA damage (alkaline unwinding assay) were assessed. The extent of cell proliferation was estimated over the next four days by a tetrazolium based (MTT) assay and by determining total intracellular LDH. Myoglobin's effects on protein and DNA synthesis were also assessed (35S-methionine and bromodeoxyuridine incorporation, respectively). Myoglobin induced dose-dependent lipid peroxidation (malondialdehyde generation) and cell death (up to 80% vital dye uptake with the 4 mg/ml challenge). Although 1 mg/ml myoglobin caused no cell death, it induced nearly complete growth arrest. This lasted for approximately three days following myoglobin removal from the media. Neither of two control proteins (albumin; lysozyme) nor a second nephrotoxin (gentamicin; 1 mg/ml) reproduced this effect. The 1 mg/ml myoglobin challenge caused an 80 to 90% depression in protein and DNA synthesis. It also induced significant DNA damage, as assessed by the alkaline unwinding assay (P Iron chelation therapy (deferoxamine) mitigated myoglobin-induced cell killing. However, its addition following myoglobin loading worsened HK-2 outgrowth by exerting a direct anti-proliferative effect. These results indicate that: (1) sublethal myoglobin toxicity can induce transient proximal tubular cell growth arrest, potentially slowing recovery from ARF; (2) this effect correlates with, and could result from, heme-induced DNA damage and a blockade in

  9. Involvement of caspase-12-dependent apoptotic pathway in ionic radiocontrast urografin-induced renal tubular cell injury

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Cheng Tien [Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Weng, Te I. [Department of Forensic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Chen, Li Ping [Department of Dentistry, Chang Gang Memorial Hospital, Chang Gang University, Taoyuan, Taiwan (China); Chiang, Chih Kang [Department of Integrated Diagnostics and Therapeutics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China); Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China); Liu, Shing Hwa, E-mail: shinghwaliu@ntu.edu.tw [Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China)

    2013-01-01

    Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect subjects in the disorder of CM-induced nephropathy. Our previous work has demonstrated that CM shows to activate the endoplasmic reticulum (ER)-related adaptive unfolding protein response (UPR) activators. Glucose-regulated protein 78 (GRP78)/eukaryotic initiation factor 2α (eIF2α)-related pathways play a protective role during the urografin (an ionic CM)-induced renal tubular injury. However, the involvement of ER stress-related apoptotic signals in the urografin-induced renal tubular cell injury remains unclear. Here, we examined by the in vivo and in vitro experiments to explore whether ER stress-regulated pro-apoptotic activators participate in urografin-induced renal injury. Urografin induced renal tubular dilation, tubular cells detachment, and necrosis in the kidneys of rats. The tubular apoptosis, ER stress-related pro-apoptotic transcriptional factors, and kidney injury marker-1 (kim-1) were also conspicuously up-regulated in urografin-treated rats. Furthermore, treatment of normal rat kidney (NRK)-52E tubular cells with urografin augmented the expressions of activating transcription factor-6 (ATF-6), C/EBP homologous protein (CHOP), Bax, caspase-12, JNK, and inositol-requiring enzyme (IRE) 1 signals. Urografin-induced renal tubular cell apoptosis was not reversed by the inhibitors of ATF-6, JNK signals or CHOP siRNA transfection, but it could be partially reversed by the inhibitor of caspase-12. Taken together, the present results and our previous findings suggest that exposure of CM/urografin activates the ER stress-regulated survival- and apoptosis-related signaling pathways in renal tubular cells. Caspase-12-dependent apoptotic pathway may be partially involved in the urografin-induced nephropathy. -- Highlights: ► Ionic contrast medium-urografin induces renal tubular cell apoptosis. ► Urografin induces the ER stress-regulated survival and apoptosis

  10. Involvement of caspase-12-dependent apoptotic pathway in ionic radiocontrast urografin-induced renal tubular cell injury

    International Nuclear Information System (INIS)

    Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect subjects in the disorder of CM-induced nephropathy. Our previous work has demonstrated that CM shows to activate the endoplasmic reticulum (ER)-related adaptive unfolding protein response (UPR) activators. Glucose-regulated protein 78 (GRP78)/eukaryotic initiation factor 2α (eIF2α)-related pathways play a protective role during the urografin (an ionic CM)-induced renal tubular injury. However, the involvement of ER stress-related apoptotic signals in the urografin-induced renal tubular cell injury remains unclear. Here, we examined by the in vivo and in vitro experiments to explore whether ER stress-regulated pro-apoptotic activators participate in urografin-induced renal injury. Urografin induced renal tubular dilation, tubular cells detachment, and necrosis in the kidneys of rats. The tubular apoptosis, ER stress-related pro-apoptotic transcriptional factors, and kidney injury marker-1 (kim-1) were also conspicuously up-regulated in urografin-treated rats. Furthermore, treatment of normal rat kidney (NRK)-52E tubular cells with urografin augmented the expressions of activating transcription factor-6 (ATF-6), C/EBP homologous protein (CHOP), Bax, caspase-12, JNK, and inositol-requiring enzyme (IRE) 1 signals. Urografin-induced renal tubular cell apoptosis was not reversed by the inhibitors of ATF-6, JNK signals or CHOP siRNA transfection, but it could be partially reversed by the inhibitor of caspase-12. Taken together, the present results and our previous findings suggest that exposure of CM/urografin activates the ER stress-regulated survival- and apoptosis-related signaling pathways in renal tubular cells. Caspase-12-dependent apoptotic pathway may be partially involved in the urografin-induced nephropathy. -- Highlights: ► Ionic contrast medium-urografin induces renal tubular cell apoptosis. ► Urografin induces the ER stress-regulated survival and apoptosis

  11. Significance of downregulation of renal organic cation transporter (SLC47A1 in cisplatin-induced proximal tubular injury

    Directory of Open Access Journals (Sweden)

    Mizuno T

    2015-07-01

    Full Text Available Tomohiro Mizuno,1–3 Waichi Sato,2,3 Kazuhiro Ishikawa,4 Yuki Terao,1 Kazuo Takahashi,2 Yukihiro Noda,5 Yukio Yuzawa,2 Tadashi Nagamatsu1 1Department of Analytical Pharmacology, Meijo University Faculty of Pharmacy, Nagoya, 2Department of Nephrology, School of Medicine, Fujita Health University, Toyoake, 3Department of Nephrology, Nagoya University School of Medicine, Nagoya, 4Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya, 5Division of Clinical Sciences and Neuropsychopharmacology, Meijo University Faculty of Pharmacy, Nagoya, Japan Background/aim: To elucidate the mechanism responsible for developing acute kidney injury in patients with diabetes mellitus, we also evaluated the issue of whether advanced glycation endproducts (AGEs influence the expressions of multi antimicrobial extrusion protein (MATE1/SLC47A1 in tubular cells. Materials and methods: To detect changing expression of MATE1/SLC47A1 in dose- and time-dependent manners, human proximal tubular epithelial cells were incubated with AGE-aggregated-human serum albumin. As a function assay for MATE1/SLC47A1, human proximal tubular epithelial cells were incubated with cisplatin or carboplatin. Results: On incubation with AGEs, the expressions of MATE1/SLC47A1 were decreased in tubular cells. In addition, the toxicities of cisplatin were increased in tubular cells that had been pretreated with AGEs. However, the toxicities of carboplatin were smaller than that of cisplatin in proximal tubular epithelial cells. Conclusion: The expression of the MATE1/SLC47A1 is decreased by AGEs, which increases the risk for proximal tubular injury. Keywords: advanced glycation endproducts, cisplatin, SLC47A1, diabetes mellitus, acute kidney injury

  12. TUBULAR GILLS” Extreme gill modification in the Thyasiroidea with the description of Ochetoctena tomasi gen. et sp. nov. (Bivalvia: Thyasiroidea)

    OpenAIRE

    Graham Oliver

    2014-01-01

    Three dimensional tubular structures of the ctenidium of some thyasirid bivalves are described for the first time. The classification of the thyasirid gill is modified accordingly into five types based on the number of demibranchs, reflection of the filaments and shape of the filaments, either rod, laminar or tubular. The tubular structure is seen in its most modified form in a chemosymbiotic abyssal species from the south-east Atlantic, which is described here as Ochetoctena tomasi gen et sp...

  13. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Flow amperometric enzymatic biosensor was constructed. •The biosensor is based on a reactor of a novel material – porous silver solid amalgam. •Tubular amalgam detector was used for determination of decrease of O2 concentration. •Covalent bonds amalgam−thiol−enzyme contributed to the sensor long-term stability. •LOD of glucose was 0.01 mmol L−1 with RSD = 1.3% (n = 11). -- Abstract: A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N′-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02–0.80 mmol L−1 with detection limit of 0.01 mmol L−1. The content of glucose in the sample of honey was determined as 35.5 ± 1.0 mass % (number of the repeated measurements n = 7; standard deviation SD = 1.2%; relative standard deviation RSD = 3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days)

  14. Three-dimensional nanotube electrode arrays for hierarchical tubular structured high-performance pseudocapacitors.

    Science.gov (United States)

    Gao, Yuan; Lin, Yuanjing; Chen, Jiaqi; Lin, Qingfeng; Wu, Yue; Su, Wenjun; Wang, Wenli; Fan, Zhiyong

    2016-07-21

    Ordered three-dimensional (3-D) tubular arrays are highly attractive candidates for high performance pseudocapacitor electrodes. Here, we report 3-D fluorine doped tin oxide (FTO) tubular arrays fabricated by a cost-effective ultrasonic spray pyrolysis (USP) method in anodic aluminum oxide (AAO) channels with high uniformity. The large surface area of such a structure leads to remarkable surface area enhancement up to 51.8 times compared to a planar structure. Combining with electrochemically deposited manganese dioxide (MnO2) nanoflakes on the inner side wall of the FTO nanotubes, the unique hierarchical tubular structured pseudocapacitor electrode demonstrated the highest areal capacitance of 193.8 mF cm(-2) at the scan rate of 5 mV s(-1) and 184 mF cm(-2) at the discharge current density of 0.6 mA cm(-2), which is 18.5 times that of a planar electrode. And it also showed a volumetric capacitance of 112.6 F cm(-3) at the scan rate of 5 mV s(-1) and 108.8 F cm(-3) at the discharge current density of 0.6 mA cm(-2). In addition, the cyclic stability test also indicated that a nanostructured pseudocapacitive electrode has a much larger capacitance retention after 3000 cycles of the charge-discharge process compared with a planar electrode, primarily due to the mechanical stability of the nanostructure. Moreover, pseudocapacitor device fabrication based on such electrodes shows the volumetric capacitance of 17.5 F cm(-3), and the highest specific energy of 1.56 × 10(-3) Wh cm(-3). With the merit of facile fabrication procedures and largely enhanced electrochemical performance, such a 3-D structure has high potency for energy storage systems for a wide range of practical applications. PMID:27337295

  15. Effect of methoxychlor on Ca(2+) movement and viability in MDCK renal tubular cells.

    Science.gov (United States)

    Cheng, He-Hsiung; Lu, Yi-Chau; Lu, Ti; Cheng, Jin-Shiung; Mar, Guang-Yuan; Fang, Yi-Chien; Chai, Kuo-Liang; Jan, Chung-Ren

    2012-10-01

    The effect of the insecticide methoxychlor on the physiology of renal tubular cells is unknown. This study aimed to explore the effect of methoxychlor on cytosolic Ca(2+) concentrations ([Ca(2+) ](i) ) in MDCK renal tubular cells using the Ca(2+) -sensitive fluorescent dye fura-2. Methoxychlor at 5-20 μM increased [Ca(2+) ](i) in a concentration-dependent manner. The signal was reduced by 80% by removing extracellular Ca(2+) . Methoxychlor-induced Ca(2+) entry was not affected by nifedipine and SK&F96365 but was inhibited by econazole and protein kinase C modulators. In Ca(2+) -free medium, treatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) partly inhibited methoxychlor-induced [Ca(2+) ](i) rise. Incubation with methoxychlor also inhibited thapsigargin- or BHQ-induced [Ca(2+) ](i) rise. Inhibition of phospholipase C with U73122 nearly abolished methoxychlor-induced [Ca(2+) ](i) rise. At 5-15 μM, methoxychlor slightly increased cell viability, whereas at 20 μM, it decreased viability. The cytotoxic effect of methoxychlor was not reversed by chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N,N-tetraacetic acid/AM (BAPTA/AM). Annexin V-FITC data suggest that 10 μM methoxychlor inhibited apoptosis, while 20 μM methoxychlor enhanced apoptosis. Methoxychlor (10 and 20 μM) increased the production of reactive oxygen species. Together, in renal tubular cells, methoxychlor induced [Ca(2+) ](i) rise by inducing phospholipase C-dependent Ca(2+) release from multiple stores and Ca(2+) entry via protein kinase C- and econazole-sensitive channels. Methoxychlor slightly enhanced or inhibited cell viability in a concentration-dependent, Ca(2+) -independent manner. Methoxychlor induced cell death that may involve apoptosis via mitochondrial pathways.

  16. Analysis of mass transfer characteristics in a tubular membrane using CFD modeling.

    Science.gov (United States)

    Yang, Jixiang; Vedantam, Sreepriya; Spanjers, Henri; Nopens, Ingmar; van Lier, Jules B

    2012-10-01

    In contrast to the large amount of research into aerobic membrane bioreactors, little work has been reported on anaerobic membrane bioreactors (AMBRs). As to the application of membrane bioreactors, membrane fouling is a key issue. Membrane fouling generally occurs more seriously in AMBRs than in aerobic membrane bioreactors. However, membrane fouling could be managed through the application of suitable shear stress that can be introduced by the application of a two-phase flow. When the two-phase flow is applied in AMBRs, little is known about the mass transfer characteristics, which is of particular importance, in tubular membranes of AMBRs. In our present work, we have employed fluid dynamic modeling to analyze the mass transfer characteristics in the tubular membrane of a side stream AMBR in which, gas-lift two-phase flow was applied. The modeling indicated that the mass transfer capacity at the membrane surface at the noses of gas bubbles was higher than the mass transfer capacity at the tails of the bubbles, which is in contrast to the results when water instead of sludge is applied. At the given mass transfer rate, the filterability of the sludge was found to have a strong influence on the transmembrane pressure at a steady flux. In addition, the model also showed that the shear stress in the internal space of the tubular membrane was mainly around 20 Pa but could be as high as about 40 Pa due to gas bubble movements. Nonetheless, at these shear stresses a stable particle size distribution was found for sludge particles.

  17. Molecular and biochemical alterations in tubular epithelial cells of patients with isolated methylmalonic aciduria.

    Science.gov (United States)

    Ruppert, T; Schumann, A; Gröne, H J; Okun, J G; Kölker, S; Morath, M A; Sauer, S W

    2015-12-15

    Methylmalonic acidurias (MMAurias) are a group of inherited disorders in the catabolism of branched-chain amino acids, odd-chain fatty acids and cholesterol caused by complete or partial deficiency of methylmalonyl-CoA mutase (mut(0) and mut(-) subtype respectively) and by defects in the metabolism of its cofactor 5'-deoxyadenosylcobalamin (cblA, cblB or cblD variant 2 type). A long-term complication found in patients with mut(0) and cblB variant is chronic tubulointerstitial nephritis. The underlying pathomechanism has remained unknown. We established an in vitro model of tubular epithelial cells from patient urine (hTEC; 9 controls, 5 mut(0), 1 cblB). In all human tubular epithelial cell (hTEC) lines we found specific tubular markers (AQP1, UMOD, AQP2). Patient cells showed disturbance of energy metabolism in glycolysis, mitochondrial respiratory chain and Krebs cycle in concert with increased reactive oxygen species (ROS) formation. Electron micrographs indicated increased autophagosome production and endoplasmic reticulum stress, which was supported by positive acridine orange staining and elevated levels of LC3 II, P62 and pIRE1. Screening mTOR signaling revealed a release of inhibition of autophagy. Patient hTEC produced and secreted elevated amounts of the pro-inflammatory cytokine IL8, which was highly correlated with the acridine orange staining. Summarizing, hTEC of MMAuria patients are characterized by disturbed energy metabolism and ROS production that lead to increased autophagy and IL8 secretion. PMID:26420839

  18. Relationship between rickets and incomplete distal renal tubular acidosis in children

    Directory of Open Access Journals (Sweden)

    Oduwole Abiola O

    2010-08-01

    Full Text Available Abstract Background In the Sub Saharan Africa Rickets has now been established to be due primarily to calcium deficiency and sometimes in combination with vitamin D deficiency. The main thrust of management is calcium supplementation with or without vitamin D. An observation was made that some children with nutritional rickets do not respond to this management modality. The recently reported high prevalence of Incomplete Distal Renal Tubular Acidosis (idRTA in adults with osteoporosis as brought to fore the possibility of this being a possible cause of calcium wastage and therefore the poor response in these group of children with rickets. Aim To determine the prevalence of idRTA amongst a cohort of subjects with rickets To show a relationship between rickets and incomplete distal renal acidosis To determine the response of children with rickets and idRTA to addition of Shohl's solution to therapy Methodology Two separate cohorts of children with rickets performed the ammonium chloride loading test to detect those with incomplete renal tubular acidosis. Following identification for idRTA, Shohl's solution was added to therapy of calcium and vitamin D supplementation and their response compared to those without idRTA on calcium and vitamin D supplementation solely. Results 50 children with rickets aged from two to six years of age and composed of 29 females and 21males were investigated. Incomplete renal tubular acidosis was found in 38% of them. Prevalence of idRTA was highest amongst those aged 3-6 years of age. Those with idRTA had worse limb deformities, biochemical and radiological parameters than those who hadn't. Rate of response on those with idRTA treated with Shohl's solution was at par with those without idRTA. Conclusion Incomplete idRTA exist amongst children with rickets and should be looked out for in severe rickets and older children. Treatment of idRTA will lead to optimal response and healing of rickets.

  19. Effect of the tubular-fan drum shapes on the performance of cleaning head module

    International Nuclear Information System (INIS)

    The geometrical effects of a tubular-fan drum on the performance improvement of the cleaning head module of a vacuum cleaner were investigated. In this study, the number of blades and the width of the blade were selected as the design parameters. Static pressure, eccentric vortex, turbulence kinetic energy (TKE) and suction efficiency were analysed and tabulated. Three-dimensional computational fluid dynamics method was used with an SST (Shear Stress Transfer) turbulence model to simulate the flow field at the suction of the cleaning head module using the commercial code ANSYS-CFX. Suction pressure distributions were graphically depicted for different values of the design parameters

  20. FBAR syndapin 1 recognizes and stabilizes highly curved tubular membranes in a concentration dependent manner

    DEFF Research Database (Denmark)

    Ramesh, Pradeep; Baroji, Younes F.; Seyyed Reihani, Seyyed Nader;

    2013-01-01

    brain lipid vesicles and show that it senses membrane curvature at low density whereas it induces and reinforces tube stiffness at higher density. FBAR strongly up-concentrates on the high curvature tubes pulled out of Giant Unilamellar lipid Vesicles (GUVs), this sorting behavior is strongly amplified...... at low protein densities. Interestingly, FBAR from syndapin 1 has a large affinity for tubular membranes with curvatures larger than its own intrinsic concave curvature. Finally, we studied the effect of FBAR on membrane relaxation kinetics with high temporal resolution and found that the protein...

  1. Early segmental changes in ischemic acute tubular necrosis of the rat kidney

    DEFF Research Database (Denmark)

    Faarup, Poul; Nørgaard, Tove; Hegedüs, Viktor;

    2004-01-01

    pentothal-anesthetized Wistar rats (body weight 200-250 g) ischemia of the right kidney was obtained by clamping (clamp diameter 0.15 mm) the ipsilateral renal artery for varying periods of time (10 min to 6 h) followed by removal and instant freezing of the kidney in isopentane at -165 degrees C...... and subsequent freeze-substitution in alcohol. The microscopic slides from the kidneys were silver methenamine-PAS stained. In the segments of the proximal convoluted tubules of the nephrons, presence of nuclear pyknosis, places of denuded basement membranes and presence of exfoliated tubular cells were counted...

  2. Effects of uric acid on mitochondrial oxidative damage and apoptosis in human renal tubular epithelial cells

    Institute of Scientific and Technical Information of China (English)

    张涛

    2014-01-01

    Objective To observe the effects of uric acid(UA)on mitochondrial oxidative damage and apoptosis in renal tubular epithelial cells(HK-2),and investigate the possible mechanism.Methods HK-2 cells were exposed to UA(480μmol/L,720μmol/L)for different time(0 h,24 h,48 h)in vitro.The mitochondrial ROS production was detected by Mito SOX staining.The mitochondrial membrane potential was measured by JC-1 staining.The expressions of prohibitin and AIF were examined by Western blotting and immunofluorescence cytochemistry.

  3. Study on crack propagation in tubular joints under compressive fatigue loadings

    OpenAIRE

    Acevedo, Claire; NUSSBAUMER, Alain

    2009-01-01

    Large scale tubular truss beams, approximately of 9 m long and 2 m high, were tested under constant amplitude fatigue loading. The beams were made out of circular hollow sections of steel S355, welded to form a uni-planar truss with K-joints, in a shape common to bridge construction. The main goal of these tests was to focus on the fatigue behavior of the joints loaded in compression that is with chord in compression, one diagonal in compression and the remaining diagonal in tension. The test...

  4. Hierarchical Porous and High Surface Area Tubular Carbon as Dye Adsorbent and Capacitor Electrode.

    Science.gov (United States)

    Chen, Long; Ji, Tuo; Brisbin, Logan; Zhu, Jiahua

    2015-06-10

    Hierarchically porous tubular carbon (HPTC) with large surface area of 1094 m(2)/g has been successfully synthesized by selectively removing lignin from natural wood. No templates or chemicals are involved during the process. By further KOH activation, surface area of activated HPTC reaches up to 2925 m(2)/g. These materials show unprecedented high adsorption capacity toward organic dyes (methylene blue, 838 mg/g; methyl orange, 264 mg/g) and large electrochemical capacitance of >200 F/g. The sustainable feature of the wood precursor and demonstrated superior adsorption and energy storage properties allow promising applications of the processed materials in energy and environmental related fields. PMID:25980528

  5. Solitary eccrine syringofibroadenoma: a case report showing papillary tubular adenoma-like features

    Directory of Open Access Journals (Sweden)

    Toshiyuki Yamamoto

    2016-10-01

    Full Text Available We herein describe a case showing eccrine syringofibroadenoma occurred on the dorsum of the right foot of a 46-year-old Japanese female. Histopathologic examination revealed anastomosing cords and strands of cuboidal epithelial cells extending from the epidermis to the upper dermis, with a number of well-defined ducts suggesting eccrine ductal origin. In addition, there were papillary tubular adenoma-like ductal structures lined by a few rows of epithelial cells with papillary projections into the lumen surrounded by fibrous stroma in the mid-dermis. It is of note that various histologic features showing different differentiation were seen in a single lesion of eccrine syringofibroadenoma.

  6. Fast Monte Carlo inversion for extracting the optical properties of tubular tissues

    Institute of Scientific and Technical Information of China (English)

    Huijuan Zhao; Xiaoqing Zhou; Julan Liang; Shunqi Zhang

    2008-01-01

    Reconstruction of absorption coefficient μa and scattering coefficient μs is very important for applications of diffuse optical tomography and near infrared spectroscopy. Aiming at the early cancer detection of cervix and stomach, we present a fast inverse Monte-Carlo scheme for extracting μa and μs of a tubular tissue from the measurement on frequency domain. Results show that the computation time for reconstructing one set of μa and μs is less than 1 rain and the relative errors in reconstruction axe less than ±10% for the optical properties of normal cervical tissue and precancerous lesions.

  7. Tubular growth and bead formation in the lyotropic lamellar phase of a lipid.

    Science.gov (United States)

    Bhatia, Tripta; Hatwalne, Yashodhan; Madhusudana, N V

    2015-07-28

    We use fluorescence confocal polarised microscopy (FCPM) to study tubular growth upon hydration of dry DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) in water and water-glycerol mixtures. We have developed a model to relate the FCPM intensity profiles to the multilamellar structures of the tubules. Insertion of an additional patch inside a tubule produces a beaded structure, while a straight configuration is retained if the growth is on the outside. We use a simple model to suggest that reduction in overall curvature energy drives bead formation. PMID:26066670

  8. Proximal renal tubular injury in rats sub-chronically exposed to low fluoride concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Cárdenas-González, Mariana C.; Del Razo, Luz M. [Departmento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), México, D. F., México (Mexico); Barrera-Chimal, Jonatan [Unidad de Fisiología Molecular, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México, D. F., México (Mexico); Jacobo-Estrada, Tania [Departmento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), México, D. F., México (Mexico); López-Bayghen, Esther [Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), México, D. F., México (Mexico); and others

    2013-11-01

    Fluoride is usually found in groundwater at a very wide range of concentration between 0.5 and 25 ppm. At present, few studies have assessed the renal effects of fluoride at environmentally relevant concentrations. Furthermore, most of these studies have used insensitive and nonspecific biomarkers of kidney injury. The aim of this study was to use early and sensitive biomarkers to evaluate kidney injury after fluoride exposure to environmentally relevant concentrations. Recently weaned male Wistar rats were exposed to low (15 ppm) and high (50 ppm) fluoride concentrations in drinking water for a period of 40 days. At the end of the exposure period, kidney injury biomarkers were measured in urine and renal mRNA expression levels were assessed by real time RT-PCR. Our results showed that the urinary kidney injury molecule (Kim-1), clusterin (Clu), osteopontin (OPN) and heat shock protein 72 excretion rate significantly increased in the group exposed to the high fluoride concentration. Accordingly, fluoride exposure increased renal Kim-1, Clu and OPN mRNA expression levels. Moreover, there was a significant dose-dependent increase in urinary β-2-microglobulin and cystatin-C excretion rate. Additionally, a tendency towards a dose dependent increase of tubular damage in the histopathological light microscopy findings confirmed the preferential impact of fluoride on the tubular structure. All of these changes occurred at early stages in which, the renal function was not altered. In conclusion using early and sensitive biomarkers of kidney injury, we were able to found proximal tubular alterations in rats sub-chronically exposed to fluoride. - Highlights: • Exposure to low concentrations of fluoride induced proximal tubular injury • Increase in urinary Kim-1, Clu, OPN and Hsp72 in 50 ppm fluoride-exposed group • Increase in urinary B2M and CysC in 15 and 50 ppm fluoride-exposed groups • Fluoride exposure increased renal Kim, Clu and OPN mRNA expression levels.

  9. Experimental study of high strength concrete-filled circular tubular columns under eccentric loading

    OpenAIRE

    Portoles, J.M.; Romero, Manuel L.; Bonet Senach, José Luís; Filippou, F.C.

    2011-01-01

    The paper describes 37 tests conducted on slender circular tubular columns filled with normal and high strength concrete subjected to eccentric axial load. The test parameters were the nominal strength of concrete (30, 70 and 90 MPa), the diameter to thickness ratio Dt, the eccentricity ratio eD and the column slenderness (LD). The experimental ultimate load of each test was compared with the design loads from Eurocode 4, which limits the strength of concrete up to 50 MPa. The aim of the pape...

  10. Numerical analysis of the fire resistance of circular and elliptical slender concrete filled tubular columns

    OpenAIRE

    Espinós Capilla, Ana

    2012-01-01

    El empleo de pilares tubulares de acero rellenos de honnigón (CFT) ha crecido en las últimas décadas, debido a su excelente comportamiento estructural, que aprovecha el efecto combinado del acero y honnigón trabajando juntos. Esta asociación ofrece una serie de ventajas que hacen de las columnas CFT una solución interesante: su alta capacidad portante o su eficiente tecnología constructiva pueden citarse entre sus beneficios ampliamente conocidos, que se completan con una eleva...

  11. Longitudinal Mechanical Properties of Small-Diameter Polyurethane Vascular Graft Reinforced by Tubular Knitted Fabric

    Institute of Scientific and Technical Information of China (English)

    ZHOU Fei; XU Wei-lin; OUYANG Chen-xi; LIU Xiu-ying; XU Hai-ye; YAO Mu

    2008-01-01

    The vascular graft with 4 nun diameter was prepared by casting one layer of polyurethane (PU) film onto the knitting tubular fabric as the reinforced support. The effects of different PU content and wall thickness on the longitudinal mechanical properties of vascular graft were investigated. The breaking elongation, breaking force, initial modulus and breaking work were studied. The results showed that the longitudinal mechanical properties of vascular graft were enhanced as the content of polyurethane increased, which resulted from the combination of PU excellent elasticity and fabric preferable strength.

  12. ApoSense: a novel technology for functional molecular imaging of cell death in models of acute renal tubular necrosis

    International Nuclear Information System (INIS)

    Acute renal tubular necrosis (ATN), a common cause of acute renal failure, is a dynamic, rapidly evolving clinical condition associated with apoptotic and necrotic tubular cell death. Its early identification is critical, but current detection methods relying upon clinical assessment, such as kidney biopsy and functional assays, are insufficient. We have developed a family of small molecule compounds, ApoSense, that is capable, upon systemic administration, of selectively targeting and accumulating within apoptotic/necrotic cells and is suitable for attachment of different markers for clinical imaging. The purpose of this study was to test the applicability of these molecules as a diagnostic imaging agent for the detection of renal tubular cell injury following renal ischemia. Using both fluorescent and radiolabeled derivatives of one of the ApoSense compounds, didansyl cystine, we evaluated cell death in three experimental, clinically relevant animal models of ATN: renal ischemia/reperfusion, radiocontrast-induced distal tubular necrosis, and cecal ligature and perforation-induced sepsis. ApoSense showed high sensitivity and specificity in targeting injured renal tubular epithelial cells in vivo in all three models used. Uptake of ApoSense in the ischemic kidney was higher than in the non-ischemic one, and the specificity of ApoSense targeting was demonstrated by its localization to regions of apoptotic/necrotic cell death, detected morphologically and by TUNEL staining. (orig.)

  13. Expression of c-met Stimulated by High Glucose in Human Renal Tubular Epithelial Cells and Its Implication

    Institute of Scientific and Technical Information of China (English)

    LI Xing; ZHANG Muxun

    2007-01-01

    The expression of c-met stimulated by high glucose in human renal tubular epithelial cells and the role of HGF/c-met system in diabetic nephropathy were examined. The proximal tubular epithelial cells were cultured in vitro under different conditions. MTT was used for the detection of cellular proliferation and RT-PCR was employed for measurement of c-met mRNA level. Our results showed that under different conditions, there were no significant differences in the proliferation of proximal tubular epithelial cells 12 h and 24 h after the culuture (P>0.05). The proliferation of proximal tubular epithelial cells showed a significant change 96 h after the culture and the cellular proliferation induced by hepatocyte growth factor (HGF) was very active (P<0.05). Moreover, no significant difference in the expression of c-met mRNA was found 12 h after the culture under different conditions (P>0.05), while 24 and 96 h after the culture, a persistent and significantly higher expression of c-met mRNA was found in HGF-induced proliferation. It is concluded that addition of exogenous HGF could inhibit the apoptosis induced by high-level glucose, promote the proliferation of proximal tubular epithelial cells, and induce the expression of c-met. Our study suggests that local up-regulation of HGF/c-met system plays an important role in the repair of renal damage in diabetic nephropathy.

  14. ApoSense: a novel technology for functional molecular imaging of cell death in models of acute renal tubular necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Damianovich, Maya; Ziv, Ilan; Aloya, Tali; Grimberg, Hagit; Levin, Galit; Reshef, Ayelet; Bentolila, Alfonso; Cohen, Avi; Shirvan, Anat [NeuroSurvival Technologies (NST) Ltd., Petah Tikva (Israel); Heyman, Samuel N.; Shina, Ahuva [Mt.Scopus and the Hebrew University Medical School, Department of Medicine, Hadassah Hospital, Jerusalem (Israel); Rosen, Seymour [Beth Israel Deaconess Medical Center and Harvard Medical School, Department of Pathology, Boston, MA (United States); Kidron, Dvora [Meir Hospital, Department of Pathology, Kfar-Saba (Israel)

    2006-03-15

    Acute renal tubular necrosis (ATN), a common cause of acute renal failure, is a dynamic, rapidly evolving clinical condition associated with apoptotic and necrotic tubular cell death. Its early identification is critical, but current detection methods relying upon clinical assessment, such as kidney biopsy and functional assays, are insufficient. We have developed a family of small molecule compounds, ApoSense, that is capable, upon systemic administration, of selectively targeting and accumulating within apoptotic/necrotic cells and is suitable for attachment of different markers for clinical imaging. The purpose of this study was to test the applicability of these molecules as a diagnostic imaging agent for the detection of renal tubular cell injury following renal ischemia. Using both fluorescent and radiolabeled derivatives of one of the ApoSense compounds, didansyl cystine, we evaluated cell death in three experimental, clinically relevant animal models of ATN: renal ischemia/reperfusion, radiocontrast-induced distal tubular necrosis, and cecal ligature and perforation-induced sepsis. ApoSense showed high sensitivity and specificity in targeting injured renal tubular epithelial cells in vivo in all three models used. Uptake of ApoSense in the ischemic kidney was higher than in the non-ischemic one, and the specificity of ApoSense targeting was demonstrated by its localization to regions of apoptotic/necrotic cell death, detected morphologically and by TUNEL staining. (orig.)

  15. Characterization of Chiral Carbonaceous Nanotubes Prepared from Four Coiled Tubular 4,4'-biphenylene-silica Nanoribbons

    Directory of Open Access Journals (Sweden)

    Shuwei Lin

    2014-04-01

    Full Text Available Four dipeptides derived from phenylalanine were synthesized, which can self-assemble into twisted nanoribbon in deionized water. The handedness of the organic self-assemblies was controlled by the chirality of the phenylalanine at the terminals. Coiled 4,4'-biphenylene bridged polybissilsesquioxane tubular nanoribbons were prepared using the organic self-assemblies as the templates. The circular dichroism spectra indicated that the biphenylene rings preferred to twist in one-handedness within the walls of the samples. After carbonization and removal of silica, single-handed coiled carbonaceous tubular nanoribbons were obtained. The Raman spectra indicated that the carbon was amorphous. The diffuse reflectance circular dichroism spectra indicated the tubular carbonaceous nanoribbons exhibited optical activity.

  16. An Interactive Tool for Outdoor Computer Controlled Cultivation of Microalgae in a Tubular Photobioreactor System

    Directory of Open Access Journals (Sweden)

    Raquel Dormido

    2014-03-01

    Full Text Available This paper describes an interactive virtual laboratory for experimenting with an outdoor tubular photobioreactor (henceforth PBR for short. This virtual laboratory it makes possible to: (a accurately reproduce the structure of a real plant (the PBR designed and built by the Department of Chemical Engineering of the University of Almería, Spain; (b simulate a generic tubular PBR by changing the PBR geometry; (c simulate the effects of changing different operating parameters such as the conditions of the culture (pH, biomass concentration, dissolved O2, inyected CO2, etc.; (d simulate the PBR in its environmental context; it is possible to change the geographic location of the system or the solar irradiation profile; (e apply different control strategies to adjust different variables such as the CO2 injection, culture circulation rate or culture temperature in order to maximize the biomass production; (f simulate the harvesting. In this way, users can learn in an intuitive way how productivity is affected by any change in the design. It facilitates the learning of how to manipulate essential variables for microalgae growth to design an optimal PBR. The simulator has been developed with Easy Java Simulations, a freeware open-source tool developed in Java, specifically designed for the creation of interactive dynamic simulations.

  17. Reduction of high-energy shock-wave-induced renal tubular injury by selenium.

    Science.gov (United States)

    Strohmaier, W L; Lahme, S; Weidenbach, P M; Bichler, K H

    1999-10-01

    In shock-wave-induced renal injury cavitation-generated free radicals play an important role. Using an in vitro model with Madin-Darby canine kidney (MDCK) cells, we investigated the influence of selenium, a free radical scavenger, in shock-wave-induced tubular cell injury. Suspensions of MDCK cells (33 x 10(6) cells/ml) were placed in small containers (volume 1.1 ml) for shock wave exposure. Two groups of 12 containers each were examined: (1) control (no medication), (2) selenium (0.4 microg/ml nutrient medium). Six containers in each group were exposed to shock waves (impulse rate 256, frequency 60 Hz, generator voltage 18 kV), while the other six containers in each group served as a control. After shock wave exposure, the concentration of cellular enzymes such as lactate dehydrogenase (LDH), N-acetyl-beta-glucosaminidase (NAG), glutamate oxaloacetate transaminase (GOT) and glutamate lactate dehydrogenase (GLDH) in the nutrient medium was examined. Following shock wave exposure there was a significant rise in LDH, NAG, GOT and GLDH concentrations. Selenium reduced this enzyme leakage significantly. Thus we conclude that selenium protects renal tubular cells against shock-wave-induced injury. Since selenium is an essential part of glutathione peroxidase, this effect seems to be mediated by a reduction in reactive oxygen species. PMID:10550528

  18. Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR

    Directory of Open Access Journals (Sweden)

    Andrea Testino

    2015-06-01

    Full Text Available Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR, has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1−xNixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO42 nanoparticles (NPs can be obtained with a production rate of about 1–10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

  19. Regulation of MUTYH, a DNA Repair Enzyme, in Renal Proximal Tubular Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Jianping Lu

    2015-01-01

    Full Text Available MUTYH is a DNA repair enzyme that initiates a base excision repair (BER by recognizing and removing 8-Oxoguanine (8-oxoG and its paired adenine. We demonstrated that both TGF-β1 and H2O2 treatment led to an increased 8-oxoG in cultured human proximal tubule epithelial (HK-2 cells, while the former induced epithelial-mesenchymal transition and the latter caused cell apoptosis. Without stimulation, HK-2 cells showed MUTYH expression in mitochondria. TGF-β1 triggered a transient upregulation of mitochondrial MUTYH and induced the expression of nuclear isoforms, while H2O2 showed no role on MUTYH expression. Ureteral obstruction (UUO mice exhibited high 8-oxoG reactivity with tubulointerstitial lesions. After obstruction, the MUTYH expression was increased only in tubules at day 3 and decreased with obvious tubular atrophy at day 10. Particularly, MUTYH was primarily located in normal tubular cytoplasm with a dominant mitochondrial form. A few cells with nuclear MUTYH expression were observed in the fibrotic interstitium. We confirmed that increased MUTYH expression was upregulated and positively correlated with the severity of kidney fibrosis. Thus, renal fibrosis caused a cell-type-specific and time-dependent response of oxidative DNA repairs, even within the same tissues. It suggests that intervention of MUTYH might be effective for therapies.

  20. Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells

    International Nuclear Information System (INIS)

    Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27Kip1, collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells

  1. Computational Fluid Dynamics Simulation of Liquid-Phase FCC Diesel Hydrotreating in Tubular Reactor

    Institute of Scientific and Technical Information of China (English)

    Li Hua; Liu Ningqiang; Zeng Zhiyu; Zou Ying; Wang Jiming

    2015-01-01

    The computational lfuid dynamics (CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hy-drotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were added to the model by user-deifned function (UDF), showing the distribution of temperature and content of sulifdes, nitrides, bicyclic aromatics and monocyclic aromatics in different parts of the reaction bed. When the pressure was 6.5 MPa, the amount of mixing hydrogen was 0.84% (m), the space velocity was 2 h-1 and the inlet temperature was 633K, the temperature reached a maximum at a height of 0.15 m, and the range of radial temperature reached its maximum (2.5 K) at a height of 0.15 m. It indicated that the proper ratio of height to diameter of catalyst bed in the tubular reactor was 5-6. The increase of inlet temperature, the mixing hydrogen and the decrease of space velocity led to the decrease in the content of bicyclic aromatics, sulifdes and nitrides, and the increase in monocyclic aromatics content, while the high temperature increased. The results were in good agreement with experimental data, indicating to the high accuracy of the model.

  2. Hysteretic Behavior of Tubular Steel Braces Having Carbon Fiber Reinforced Polymer Reinforcement Around End Net Sections

    Directory of Open Access Journals (Sweden)

    Cem Haydaroğlu

    2015-12-01

    Full Text Available This study presents an experimental investigation into the seismic retrofit of tubular steel braces using carbon fiber reinforced polymer (CFRP members. CFRP retrofitting of net sections for compact tubes are proposed for delaying potential local net section failure. A total of almost full-scale three (TB-1, TB-2, and TB-3 compact steel tubular specimens were designed per AISC specifications, constructed, and cyclically tested to fracture. Retrofitted braces, when compared to the reference specimen, developed fuller hysteretic curves. Increase in cumulative hysteretic energy dissipation and the elongation in fracture life in the specimen retrofitted with CFRP plates and CFRP sheet wraps at net sections are observed during testing. This resulted in a maximum of 82.5% more dissipated energy for compact tube specimens. Also, this retrofit provided a longer experimental fracture life (maximum 59% more. Due to fracture initiation during the last cycles, significant reductions in strength and stiffness have been obtained. No significant change (maximum 10% in the brace stiffness was observed, which could be desirable in seismic retrofit applications. Pushover analysis per FEMA 356 for the bare specimen shows that FEMA does not represent actual brace behavior in the compression side although pushover and experimental results are in good agreement in the tension side.

  3. Ca(2+) signalling in human proximal tubular epithelial cells deficient for cystinosin.

    Science.gov (United States)

    Ivanova, Ekaterina A; Elmonem, Mohamed A; Bongaerts, Inge; Luyten, Tomas; Missiaen, Ludwig; van den Heuvel, Lambertus P; Levtchenko, Elena N; Bultynck, Geert

    2016-10-01

    Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder caused by loss-of-function mutations in the CTNS gene coding for the lysosomal cystine transporter, cystinosin. Recent studies have demonstrated that, apart from cystine accumulation in the lysosomes, cystinosin-deficient cells, especially renal proximal tubular epithelial cells are characterized by abnormal vesicle trafficking and endocytosis, possible lysosomal dysfunction and perturbed intracellular signalling cascades. It is therefore possible that Ca(2+) signalling is disturbed in cystinosis, as it has been demonstrated for other disorders associated with lysosomal dysfunction, such as Gaucher, Niemann-Pick type C and Alzheimer's diseases. In this study we investigated ATP-induced, IP3-induced and lysosomal Ca(2+) release in human proximal tubular epithelial cells derived from control and cystinotic patients. No major dysregulation of intracellular Ca(2+) dynamics was found, although ATP-induced Ca(2+) release appeared slightly sensitized in cystinotic cells compared to control cells. Hence, these subtle changes in Ca(2+) signals elicited by agonists may contribute to the pathogenesis of the disease.

  4. Experimental and modeling study of sulfur dioxide oxidation in packed-bed tubular reactor

    Directory of Open Access Journals (Sweden)

    Hanen NOURI

    2013-08-01

    Full Text Available The conversion of sulfur dioxide into sulfur trioxide is a reaction which interests not only the industry of sulfuric acid production but also the processes of pollution control of certain gas effluents containing SO2. This exothermic reaction needs a very good control of temperature, that's why it is led in the industry in a multistage converter with intermediate heat exchangers. Microreactors represent a good alternative for such reaction due to their intensification of mass and heat transfer and enhancement of temperature control. In this study, this reaction was conducted in a stainless steel tubular (4mm ID packed bed reactor using particles of vanadium pentoxide as catalyst at atmospheric pressure. Experiments were performed with different inlet SO2 concentration in 3-9% range and reaction temperature between 685-833K. We noticed that the conversion decreases with the amount of SO2 and increases with the temperature until an optimum, above this value the conversion drop according to the shape of the equilibrium curve. Controlling rate mechanism is studied by varying temperature. Pseudohomogeneous perfect plug flow is used to describe this small tubular reactor. Numerical simulations with MATLAB were performed to validate the experimental results. Good agreement between the model predictions and the experimental results is achieved. Fluid flow description inside the packed bed reactor was performed by using the free fluid and porous media flow model. This model was solved by the commercial software COMSOL Multiphysics. Velocity profile inside the reactor is theoretically obtained.

  5. Enhanced Flexible Tubular Microelectrode with Conducting Polymer for Multi-Functional Implantable Tissue-Machine Interface

    Science.gov (United States)

    Tian, Hong-Chang; Liu, Jing-Quan; Kang, Xiao-Yang; Tang, Long-Jun; Wang, Ming-Hao; Ji, Bo-Wen; Yang, Bin; Wang, Xiao-Lin; Chen, Xiang; Yang, Chun-Sheng

    2016-05-01

    Implantable biomedical microdevices enable the restoration of body function and improvement of health condition. As the interface between artificial machines and natural tissue, various kinds of microelectrodes with high density and tiny size were developed to undertake precise and complex medical tasks through electrical stimulation and electrophysiological recording. However, if only the electrical interaction existed between electrodes and muscle or nerve tissue without nutrition factor delivery, it would eventually lead to a significant symptom of denervation-induced skeletal muscle atrophy. In this paper, we developed a novel flexible tubular microelectrode integrated with fluidic drug delivery channel for dynamic tissue implant. First, the whole microelectrode was made of biocompatible polymers, which could avoid the drawbacks of the stiff microelectrodes that are easy to be broken and damage tissue. Moreover, the microelectrode sites were circumferentially distributed on the surface of polymer microtube in three dimensions, which would be beneficial to the spatial selectivity. Finally, the in vivo results confirmed that our implantable tubular microelectrodes were suitable for dynamic electrophysiological recording and simultaneous fluidic drug delivery, and the electrode performance was further enhanced by the conducting polymer modification.

  6. Structural Design Considerations for Tubular Power Tower Receivers Operating at 650 Degrees C: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Neises, T. W.; Wagner, M. J.; Gray, A. K.

    2014-04-01

    Research of advanced power cycles has shown supercritical carbon dioxide power cycles may have thermal efficiency benefits relative to steam cycles at temperatures around 500 - 700 degrees C. To realize these benefits for CSP, it is necessary to increase the maximum outlet temperature of current tower designs. Research at NREL is investigating a concept that uses high-pressure supercritical carbon dioxide as the heat transfer fluid to achieve a 650 degrees C receiver outlet temperature. At these operating conditions, creep becomes an important factor in the design of a tubular receiver and contemporary design assumptions for both solar and traditional boiler applications must be revisited and revised. This paper discusses lessons learned for high-pressure, high-temperature tubular receiver design. An analysis of a simplified receiver tube is discussed, and the results show the limiting stress mechanisms in the tube and the impact on the maximum allowable flux as design parameters vary. Results of this preliminary analysis indicate an underlying trade-off between tube thickness and the maximum allowable flux on the tube. Future work will expand the scope of design variables considered and attempt to optimize the design based on cost and performance metrics.

  7. Multilayer chitosan-based open tubular capillary anion exchange column with integrated monolithic capillary suppressor

    International Nuclear Information System (INIS)

    Highlights: ► Uses a multilayer chitosan–glutaraldehyde coating as anion exchanger. ► Uses a methacrylate-acrylic acid polymer monolith as suppressor. ► Demonstrates first integral suppressor open tubular anion chromatography. - Abstract: We describe a multilayered open tubular anion exchange column fabricated by alternately pumping solutions of chitosan and glutaraldehyde. The column is terminated in an integrally bonded monolithic suppressor cast around a mandrel of a tungsten wire, composed of an acrylic acid (AA)–ethylene dimethacrylate (EDMA) monolith that is made with sufficient porogen for the monolith to function as a membrane. For a 4.5 m long 75 μm bore column coated with 24 successive layers of the condensation polymer (estimated to contain ∼72 molecular layers) and coupled to 1 cm length of a suppressor fabricated with 55–60% AA, effective separation of several common anions (F−, Cl−, NO2−, Br−, NO3−, average number of theoretical plates ∼12,000) and adequate suppression of 1 mM KOH used as eluent was observed at a flow rate of 800 nL min−1 to obtain sub-picomol detection limits at an operating pressure of ∼1 bar. The separation is not time efficient but the system can be meritorious in unique niche applications where a small form factor is desired and liquid volume and power consumption are more important than separation speed.

  8. Microalgae cultivation in a tubular bioreactor and utilization of their cells

    Science.gov (United States)

    Koyu, Hon-Nami; Shunji, Kunito

    1998-03-01

    In this study on the possiblities of microalgae technology as an option for CO2 mitigation, many microalgae were isolated from seawater. Some species of the isolates, Chlamydomonas sp. strain YA-SH-1, which accumulates starch in cells under light and ferment ethanol in dark and anaerobic condition, was grown outdoors by using 50-L tubular bioreactors in batch cultivation and harvested. Using these cells, the performance of ethanol production was examined quantitatively in a 0.5-L scale fermentor. Another species, Tetraselmis sp. strain Tt-1, was cultivated in a semi-batch manner by a similar type of tubular bioreactor indoors and examined for its utilization. Tests showed these cells could be used as partial substitute for wood and kenaf pulp for processing into paper. With the idea of making microalgae produce cellulose by genetic engineering in their minds, the authors studied the structure of bacterial cellulose synthase genes and the low temperature-induced, reversible flocculation in a thermophilic blue green alga (Cyanobacterium), Synechocystis vulcanus in order to examine the feasibility of using these genes as gene source and the cynanobacterium as host.

  9. Pathology of the idiopathic renal tubular proteinuria evaluated by the renal scintigram

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, Takeshi; Saotome, Yumiko; Fuse, Tomoko [Tokyo Fussa Hospital (Japan)] [and others

    1998-03-01

    In 10 patients matching to the temporal standards of the idiopathic renal tubular proteinuria disease, renal scintigrams using {sup 99m}Tc-dimercaptosuccinic acid (DMSA) and {sup 99m}Tc-mercaptoacetyl-glycylglycylglycine (MAG3) were performed. All patients were boys with age of 11.9 years and the median concentration of {beta}{sub 2}-macroglobulin in urea was 69,150 {mu}g/l. In the DMSA scintigram, there was no abnormalities of accumulation in the morphology, but %uptake of DMSA in all patients decreased, and that ranges from 2.8 to 10.9% per kidney, equivalent to 1/3 to 1/5 of the normal healthy controls. On the other hand, in the MAG3 scintigram, the vessel and the functional phases seemed to be normal except one case, but the excretion phase was delayed except one case. This disease had the impairment in the active transport on the vessel cavity side of the distal renal tubular cells, and will show in future symptoms other than the low molecular weight proteinuria. It is important to observe carefully the development of symptoms. (K.H.)

  10. Roles of Akt and SGK1 in the Regulation of Renal Tubular Transport

    Directory of Open Access Journals (Sweden)

    Nobuhiko Satoh

    2015-01-01

    Full Text Available A serine/threonine kinase Akt is a key mediator in various signaling pathways including regulation of renal tubular transport. In proximal tubules, Akt mediates insulin signaling via insulin receptor substrate 2 (IRS2 and stimulates sodium-bicarbonate cotransporter (NBCe1, resulting in increased sodium reabsorption. In insulin resistance, the IRS2 in kidney cortex is exceptionally preserved and may mediate the stimulatory effect of insulin on NBCe1 to cause hypertension in diabetes via sodium retention. Likewise, in distal convoluted tubules and cortical collecting ducts, insulin-induced Akt phosphorylation mediates several hormonal signals to enhance sodium-chloride cotransporter (NCC and epithelial sodium channel (ENaC activities, resulting in increased sodium reabsorption. Serum- and glucocorticoid-inducible kinase 1 (SGK1 mediates aldosterone signaling. Insulin can stimulate SGK1 to exert various effects on renal transporters. In renal cortical collecting ducts, SGK1 regulates the expression level of ENaC through inhibition of its degradation. In addition, SGK1 and Akt cooperatively regulate potassium secretion by renal outer medullary potassium channel (ROMK. Moreover, sodium-proton exchanger 3 (NHE3 in proximal tubules is possibly activated by SGK1. This review focuses on recent advances in understanding of the roles of Akt and SGK1 in the regulation of renal tubular transport.

  11. Synthesis and characterization of branched yttrium hydroxide fluoride microcrystals with hierarchical tubular structure

    Institute of Scientific and Technical Information of China (English)

    TIAN Li; JIANG Wentao; SUN Qiliang; LIU Jin

    2012-01-01

    Hexagonal yttrium hydroxide fluoride microcrystals were prepared by a two-step hydrothermal route using yttrium nitrate,sodium hydroxide and sodium fluoride as raw materials to react in propanetriol solvent.The samples were characterized by powder X-ray diffraction (XRD),energy dispersive spectrum (EDS),scanning electron microscopy (SEM),transmission electron microscopy (TEM),Fourier transform infrared spectroscopy (FT-IR),thermogravimetre and differential-thermogravimetric analysis (TG-DTA),which revealed that Y(OH)2.14F0.86 microcrystals were multi-branched and that the branches of Y(OH)2.14F0.86 microcrystals were composed of hierarchical tubes.This novel multi-branched and intriguing hierarchical tubular structure of yttrium hydroxide fluoride maybe has a potential application in photoelectric crystals.The formation of branched Y(OH)2.14F0.86 microcrystals with hierarchical tubular structure were due to the substitution reaction and Oswald ripening.

  12. Complications of Minimally Invasive, Tubular Access Surgery for Cervical, Thoracic, and Lumbar Surgery

    Directory of Open Access Journals (Sweden)

    Donald A. Ross

    2014-01-01

    Full Text Available The object of the study was to review the author’s large series of minimally invasive spine surgeries for complication rates. The author reviewed a personal operative database for minimally access spine surgeries done through nonexpandable tubular retractors for extradural, nonfusion procedures. Consecutive cases (n=1231 were reviewed for complications. There were no wound infections. Durotomy occurred in 33 cases (2.7% overall or 3.4% of lumbar cases. There were no external or symptomatic internal cerebrospinal fluid leaks or pseudomeningoceles requiring additional treatment. The only motor injuries were 3 C5 root palsies, 2 of which resolved. Minimally invasive spine surgery performed through tubular retractors can result in a low wound infection rate when compared to open surgery. Durotomy is no more common than open procedures and does not often result in the need for secondary procedures. New neurologic deficits are uncommon, with most observed at the C5 root. Minimally invasive spine surgery, even without benefits such as less pain or shorter hospital stays, can result in considerably lower complication rates than open surgery.

  13. IGF-1 protects tubular epithelial cells during injury via activation of ERK/MAPK signaling pathway

    Science.gov (United States)

    Wu, Zengbin; Yu, Yang; Niu, Lei; Fei, Aihua; Pan, Shuming

    2016-01-01

    Injury of renal tubular epithelial cells can induce acute renal failure and obstructive nephropathy. Previous studies have shown that administration of insulin-like growth factor-1 (IGF-1) ameliorates the renal injury in a mouse unilateral ureteral obstruction (UUO) model, whereas the underlying mechanisms are not completely understood. Here, we addressed this question. We found that the administration of IGF-1 significantly reduced the severity of the renal fibrosis in UUO. By analyzing purified renal epithelial cells, we found that IGF-1 significantly reduced the apoptotic cell death of renal epithelial cells, seemingly through upregulation of anti-apoptotic protein Bcl-2, at protein but not mRNA level. Bioinformatics analyses and luciferase-reporter assay showed that miR-429 targeted the 3′-UTR of Bcl-2 mRNA to inhibit its protein translation in renal epithelial cells. Moreover, IGF-1 suppressed miR-429 to increase Bcl-2 in renal epithelial cells to improve survival after UUO. Furthermore, inhibition of ERK/MAPK signaling pathway in renal epithelial cells abolished the suppressive effects of IGF-1 on miR-429 activation, and then the enhanced effects on Bcl-2 in UUO. Thus, our data suggest that IGF-1 may protect renal tubular epithelial cells via activation of ERK/MAPK signaling pathway during renal injury. PMID:27301852

  14. Intracellular kinases mediate increased translation and secretion of netrin-1 from renal tubular epithelial cells.

    Directory of Open Access Journals (Sweden)

    Calpurnia Jayakumar

    Full Text Available BACKGROUND: Netrin-1 is a laminin-related secreted protein, is highly induced after tissue injury, and may serve as a marker of injury. However, the regulation of netrin-1 production is not unknown. Current study was carried out in mouse and mouse kidney cell line (TKPTS to determine the signaling pathways that regulate netrin-1 production in response to injury. METHODS AND PRINCIPAL FINDINGS: Ischemia reperfusion injury of the kidney was induced in mice by clamping renal pedicle for 30 minutes. Cellular stress was induced in mouse proximal tubular epithelial cell line by treating with pervanadate, cisplatin, lipopolysaccharide, glucose or hypoxia followed by reoxygenation. Netrin-1 expression was quantified by real time RT-PCR and protein production was quantified using an ELISA kit. Cellular stress induced a large increase in netrin-1 production without increase in transcription of netrin-1 gene. Mitogen activated protein kinase, ERK mediates the drug induced netrin-1 mRNA translation increase without altering mRNA stability. CONCLUSION: Our results suggest that netrin-1 expression is suppressed at the translational level and MAPK activation leads to rapid translation of netrin-1 mRNA in the kidney tubular epithelial cells.

  15. The role of the pericardium in the valveless, tubular heart of the tunicate Ciona savignyi.

    Science.gov (United States)

    Waldrop, Lindsay D; Miller, Laura A

    2015-09-01

    Tunicates, small invertebrates within the phylum Chordata, possess a robust tubular heart which pumps blood through their open circulatory systems without the use of valves. This heart consists of two major components: the tubular myocardium, a flexible layer of myocardial cells that actively contracts to drive fluid down the length of the tube; and the pericardium, a stiff, outer layer of cells that surrounds the myocardium and creates a fluid-filled space between the myocardium and the pericardium. We investigated the role of the pericardium through in vivo manipulations on tunicate hearts and computational simulations of the myocardium and pericardium using the immersed boundary method. Experimental manipulations reveal that damage to the pericardium results in aneurysm-like bulging of the myocardium and major reductions in the net blood flow and percentage closure of the heart's lumen during contraction. In addition, varying the pericardium-to-myocardium (PM) diameter ratio by increasing damage severity was positively correlated with peak dye flow in the heart. Computational simulations mirror the results of varying the PM ratio experimentally. Reducing the stiffness of the myocardium in the simulations reduced mean blood flow only for simulations without a pericardium. These results indicate that the pericardium has the ability to functionally increase the stiffness of the myocardium and limit myocardial aneurysms. The pericardium's function is likely to enhance flow through the highly resistive circulatory system by acting as a support structure in the absence of connective tissue within the myocardium. PMID:26142414

  16. Three-dimensional nanotube electrode arrays for hierarchical tubular structured high-performance pseudocapacitors

    Science.gov (United States)

    Gao, Yuan; Lin, Yuanjing; Chen, Jiaqi; Lin, Qingfeng; Wu, Yue; Su, Wenjun; Wang, Wenli; Fan, Zhiyong

    2016-07-01

    Ordered three-dimensional (3-D) tubular arrays are highly attractive candidates for high performance pseudocapacitor electrodes. Here, we report 3-D fluorine doped tin oxide (FTO) tubular arrays fabricated by a cost-effective ultrasonic spray pyrolysis (USP) method in anodic aluminum oxide (AAO) channels with high uniformity. The large surface area of such a structure leads to remarkable surface area enhancement up to 51.8 times compared to a planar structure. Combining with electrochemically deposited manganese dioxide (MnO2) nanoflakes on the inner side wall of the FTO nanotubes, the unique hierarchical tubular structured pseudocapacitor electrode demonstrated the highest areal capacitance of 193.8 mF cm-2 at the scan rate of 5 mV s-1 and 184 mF cm-2 at the discharge current density of 0.6 mA cm-2, which is 18.5 times that of a planar electrode. And it also showed a volumetric capacitance of 112.6 F cm-3 at the scan rate of 5 mV s-1 and 108.8 F cm-3 at the discharge current density of 0.6 mA cm-2. In addition, the cyclic stability test also indicated that a nanostructured pseudocapacitive electrode has a much larger capacitance retention after 3000 cycles of the charge-discharge process compared with a planar electrode, primarily due to the mechanical stability of the nanostructure. Moreover, pseudocapacitor device fabrication based on such electrodes shows the volumetric capacitance of 17.5 F cm-3, and the highest specific energy of 1.56 × 10-3 Wh cm-3. With the merit of facile fabrication procedures and largely enhanced electrochemical performance, such a 3-D structure has high potency for energy storage systems for a wide range of practical applications.Ordered three-dimensional (3-D) tubular arrays are highly attractive candidates for high performance pseudocapacitor electrodes. Here, we report 3-D fluorine doped tin oxide (FTO) tubular arrays fabricated by a cost-effective ultrasonic spray pyrolysis (USP) method in anodic aluminum oxide (AAO) channels with

  17. Advanced Monobore Concept, Development of CFEX Self-Expanding Tubular Technology

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Spray

    2007-09-30

    The Advanced Monobore Concept--CFEX{copyright} Self-Expanding Tubular Technology Development was a successfully executed fundamental research through field demonstration project. This final report is presented as a progression, according to basic technology development steps. For this project, the research and development steps used were: concept development, engineering analysis, manufacturing, testing, demonstration, and technology transfer. The CFEX{copyright} Technology Development--Advanced Monobore Concept Project successfully completed all of the steps for technology development, covering fundamental research, conceptual development, engineering design, advanced-level prototype construction, mechanical testing, and downhole demonstration. Within an approximately two year period, a partially defined, broad concept was evolved into a substantial new technological area for drilling and production engineering applicable a variety of extractive industries--which was also successfully demonstrated in a test well. The demonstration achievement included an actual mono-diameter placement of two self-expanding tubulars. The fundamental result is that an economical and technically proficient means of casing any size of drilling or production well or borehole is indicated as feasible based on the results of the project. Highlighted major accomplishments during the project's Concept, Engineering, Manufacturing, Demonstration, and Technology Transfer phases, are given.

  18. Computer aided modeling and simulation of hydroforming on tubular engineering products

    Directory of Open Access Journals (Sweden)

    Jeremy (Zheng Li

    2013-01-01

    Full Text Available Hydroforming processes have been widely applied in many different industrial fields including aerospace, automotive, and modern plastics for weight-reduction and strength enhancement. Hydroforming on tubular products is better than the process of welding tubular assemblies from stampings including increased strength, reduction of work applied to the unit weight, decreased processing and tool costs, improved structural stability, less secondary operation, enhanced stiffness, and more uniform in product thickness. Although the hydroforming becomes popular manufacturing methodology, few researches have been done to study the hydroforming mechanism through computational modeling and simulation. This paper focuses on the study of hydroforming process and mechanism based on computer-aided modeling (FEA and prototype testing to determine the material behaviors in hydroforming process. The objective of this research is to verify the effects of major manufacturing parameters on hydroforming processes. The computational analysis and prototype testing indicate that some factors including applied internal pressure path and compressive axial loading play important roles in hydroforming deformation. Both computer-aided modeling and prototyping experiment show close results which verifies the credibility of this research and analytic methodology.

  19. Helical nanostructure of tubular metal-organic complex synthesized by sonochemical process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Tubular metal-organic complex (C2H9N2)2(C2H10N2)0.5[MoO2(OC6H4O)2] has been synthesized. The title complex crystallizes in the tetragonal system, space group P4(2)/n with a = 25.214(8), c = 7.484(4) ?, and Z = 8. The X-ray structural analysis of the complex reveals tube-like framework which is stabilized by hydrogen bond. Chiral anions [Mo(V)O2(OC6H4O)2]3? of the complex have two types of isomers(λ /δ configuration). Helical nanostructure of this metal-organic complex was formed using a sonochemical method. Sonocation may lead to the transformation from the bulk tubular complex to the helical nanostructure. The as-synthesized nanohelices were all double-stranded and left- and right-handed nanohelices were both formed. The helical nanostructure is a new morphology of inorganic-organic hybrid materials on the nanoscale level and the exact formation mechanism of these helices still needs further investigation.

  20. Large axial actuation of pre-stretched tubular dielectric elastomer and use of oil encapsulation to enhance dielectric breakdown strength

    Science.gov (United States)

    Lau, Gih-Keong; Di-Teng Tan, Desmond; La, Thanh-Giang

    2015-04-01

    Rolled dielectric elastomer actuators (DEAs) are subjected to necking and non-uniform deformation upon pre-stress relaxation. Though rolled up from flat DEAs, they performed much poorer than the flat ones. Their electrically induced axial strains were previously reported as not more than 37.3%, while the flat ones produced greater than 100% strain. Often, the rolled DEAs succumb to premature breakdown before they can realize the full actuation potential like the flat ones do. This study shows that oil encapsulation, together with large hoop pre-stretch, helps single-wound rolled DEAs, which are also known as tubular DEAs, suppress premature breakdown. Consequently, the oil-encapsulated tubular DEAs can sustain higher electric fields, and thus produce larger isotonic strain and higher isometric stress change. Under isotonic testing, they sustained very high electric fields of up to 712.7 MV m-1, which is approximately 50% higher than those of the dry tubular DEAs. They produced up to 55.4% axial isotonic strain despite axially stiffening by the passive oil capsules. In addition, due to the use of large hoop pre-stretch, even the dry tubular DEAs without oil encapsulation achieved a very large axial strain of up to 84.2% compared to previous works. Under isometric testing, the oil-encapsulated tubular DEA with enhanced breakdown strength produced an axial stress change of up to nearly 0.6 MPa, which is 114% higher than that produced by the dry ones. In conclusion, the oil encapsulation and large pre-stretch help realize fuller actuation potential of tubular dielectric elastomer, which is subjected to initially non-uniform deformation.

  1. Vitamin E attenuates crystal formation in rat kidneys: roles of renal tubular cell death and crystallization inhibitors.

    Science.gov (United States)

    Huang, H-S; Chen, J; Chen, C-F; Ma, M-C

    2006-08-01

    We previously reported that oxidative stress and renal tubular damage occur in chronic hyperoxaluric rats. However, the in vivo responses of renal epithelial cells after vitamin E administration and their correlations with calcium oxalate (CaOx) crystal formation have not been evaluated. Male Wistar rats received 0.75% ethylene glycol (EG) for 7, 21, or 42 days to induce CaOx deposition (EG group). Another group of EG-treated rats received 200 mg kg(-1) of vitamin E intraperitoneally (EG+E group) to evaluate its effect on hyperoxaluria. Urinary electrolytes and biochemistry and levels of lipid peroxides and enzymes were examined, together with serum vitamin E levels. Levels of the tubular markers, alpha and mu glutathione S-transferase, proliferating cell nuclear antigen (PCNA), osteopontinin (OPN), and Tamm-Horsfall protein (THP) were also measured, and TUNEL staining was performed to examine the viability of the tubular epithelium. There were no significant differences between the two age-matched controls either untreated or given vitamin E. Compared to untreated controls, tubular cell death was increased at all time points in EG rats with a gradual increase in CaOx crystals, whereas the number of PCNA-positive cells was only significantly increased on day 21. In EG+E rats, tubular cell death was decreased compared to the EG group, and cell proliferation was seen at all time points, while CaOx crystal deposition was decreased, but hyperoxaluria, urinary lipid peroxides, and enzymuria were unaffected. Vitamin E supplement prevented the loss of OPN and THP in renal tissues by EG and the reduction in their levels in the urine. The beneficial effect of vitamin E in reducing CaOx accumulation is due to attenuation of tubular cell death and enhancement of the defensive roles of OPN and THP.

  2. In-situ Measurements of the Effect of Au Doping in Ni Catalysts on the Yield of Tubular Carbon Nanostructures

    DEFF Research Database (Denmark)

    Sharma, Renu; Chee, S.; Rez, P.;

    . Here we show that the yield of tubular carbon structures can be increased by doping a Ni catalyst with Au, and that their morphology and structure can be controlled by varying the reaction temperature. However, the exact role of Au for catalysis is not well understood. Au/Ni thin films (1-2 nm...... with herring-bone, stacked rings and multiwalled structure were observed to form depending upon the reaction temperature and pressure. Atomic resolution videos reveal that the graphene layers (the essential topological form of carbon for tubular growth) form at facets of the crystalline catalyst particles...

  3. Ozônio na esterilização de produtos para assistência à saúde: revisão integrativa da literatura

    Directory of Open Access Journals (Sweden)

    Cristina Silva Sousa

    2011-10-01

    Full Text Available Estudo de revisão integrativa da literatura com o objetivo de buscar evidências que subsidiem a incorporação do ozônio como agente esterilizante de produtos para saúde. A busca foi realizada nas bases MEDLINE, SCOPUS, COCHRANE, COMPENDEX, INSPEC E ENGINEERING RESEARCH DATABASE, utilizando-se os descritores ozone e sterilization. Foram obtidas cinco publicações, entre 1990 e 2008, que testaram o ozônio como esterilizante. Todas utilizaram o mesmo tipo de investigação (experimental laboratorial e alcançaram esterilização pelo ozônio, porém com variados escopos e produtos testados, além de diversos procedimentos metodológicos. Tendo em vista a incessante tecnologia de novos produtos, com ampla variedade de conformações e matéria-prima, os achados denotam o ozônio um método promissor, porém ainda em fase inicial de investigação. Mais estudos experimentais ainda são necessários, de maneira a subsidiar evidências mais amplas sobre suas possibilidades e limitações.

  4. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    Energy Technology Data Exchange (ETDEWEB)

    Josypčuk, Bohdan, E-mail: josypcuk@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Barek, Jiří [Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic); Josypčuk, Oksana [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic)

    2013-05-17

    Graphical abstract: -- Highlights: •Flow amperometric enzymatic biosensor was constructed. •The biosensor is based on a reactor of a novel material – porous silver solid amalgam. •Tubular amalgam detector was used for determination of decrease of O{sub 2} concentration. •Covalent bonds amalgam−thiol−enzyme contributed to the sensor long-term stability. •LOD of glucose was 0.01 mmol L{sup −1} with RSD = 1.3% (n = 11). -- Abstract: A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N′-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02–0.80 mmol L{sup −1} with detection limit of 0.01 mmol L{sup −1}. The content of glucose in the sample of honey was determined as 35.5 ± 1.0 mass % (number of the repeated measurements n = 7; standard deviation SD = 1.2%; relative standard deviation RSD = 3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days)

  5. ESTUDO DA ADESÃO À TERAPIA ANTIRRETROVIRAL PARA HIV/AIDS DE PACIENTES ATENDIDOS NO MUNICÍPIO DE TOLEDO/PR

    Directory of Open Access Journals (Sweden)

    Jaqueline Alice Lorscheider

    2015-12-01

    Full Text Available No início da década de 1980 começaram a ser identificados os primeiros casos da Síndrome da Imunodeficiência Adquirida (AIDS e após mais de duas décadas da descoberta do Vírus da Imunodeficiência Humana (HIV, ainda nos deparamos com desafios para a compreensão dos vários aspectos suscitados por essa epidemia. Devido aos avanços nas pesquisas e possibilidades de tratamento, a AIDS tornou-se uma doença crônica, com aumento relevante da qualidade de vida de pessoas acometidas, o que traz novos desafios para sua compreensão e enfrentamento. Nessa perspectiva, a adesão ao tratamento antirretroviral tem sido priorizada nas políticas públicas de países como o Brasil. O objetivo deste estudo foi verificar o nível de adesão ao tratamento antirretroviral de pacientes atendidos na Farmácia do CTA/Ciscopar, por meio de uma pesquisa de campo, na qual se coletou dados a partir de questionário semiestruturado aplicados entre Junho e Agosto de 2011 e por meio das informações contidas nos prontuários. Conclui-se que embora os resultados tenham sido satisfatórios, a equipe deve sempre estar atenta aos sinais de não adesão ao tratamento, para evitar a falência terapêutica através do surgimento de resistência viral aos medicamentos.

  6. Types of transdifferentiation of renal tubular epithelial cells and its role in kidney diseases%肾小管上皮细胞转分化类型及其在肾脏疾病进展中的作用

    Institute of Scientific and Technical Information of China (English)

    王轩; 袁伟杰

    2012-01-01

    The normal shape and functions of renal tubular epithelial cells are very important for keeping renal function. Under pathological conditions, renal tubular epithelial cells transform to myofibroblast or immunocytes. The trans-differentiation of renal tubular epithelial cells acts in the progresses of many kidney diseases, such as diabetic nephropathy and lupus nephritis. In this review, we summarize the types of transdifferentiation of renal tubular epithelial cells and its roles in kidney diseases.

  7. Viabilidad Económica de la Utilización de Biogás para la Conversión en Energía Eléctrica Economic Viability of using Biogas for Electrical Power Generation

    OpenAIRE

    Ricardo G Cervi; Maura S. T. Esperancini; Osmar de C Bueno

    2011-01-01

    Se ha determinado la viabilidad económica para la conversión del biogás en electricidad, a partir del aprovechamiento de desechos de un criadero de cerdos. El biodigestor analizado es un modelo tubular continuo, con zanja para agua en albañilería y un contenedor cerrado, hermético e impermeable, donde son depositados diariamente los desechos de 2300 cerdos. La inversión inicial para implementación fue estimado en aproximadamente R$ 51.537 y los costos anuales del sistema fueron de R$ 5.700 co...

  8. Dynamic Response of RPC-Filled Steel Tubular Columns with High Load Carrying Capacity Under Axial Impact Loading

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhimin; WU Ping'an; JIA Jianwei

    2008-01-01

    Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted, and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method.Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of columns were obtained.

  9. 78 FR 9368 - Certain Oil Country Tubular Goods From the People's Republic of China: Preliminary Results of...

    Science.gov (United States)

    2013-02-08

    ...The Department of Commerce (``the Department'') is conducting an administrative review of the countervailing duty order on certain oil country tubular goods (``OCTG'') from the People's Republic of China (``PRC''). The period of review (``POR'') is January 1, 2011, through December 31, 2011. We preliminarily determine that Wuxi Seamless Oil Pipe Co., Ltd. (``Wuxi'') and Jiangsu Chengde Steel......

  10. Albumin-bound fatty acids induce mitochondrial oxidant stress and impair antioxidant responses in proximal tubular cells

    NARCIS (Netherlands)

    Ishola, D. A.; Post, J. A.; van Timmeren, M. M.; Bakker, S. J. L.; Goldschmeding, R.; Koomans, H. A.; Braam, B.; Joles, J. A.

    2006-01-01

    Albumin induces oxidative stress and cytokine production in proximal tubular cells (PTECs). Albumin-bound fatty acids (FAs) enhance tubulopathic effects of albumin in vivo. We proposed that FA aggravation of albumin-induced oxidative stress in PTECs might be involved. We hypothesized that mitochondr

  11. Characterization of connective tissue growth factor expression in primary cultures of human tubular epithelial cells: modulation by hypoxia

    NARCIS (Netherlands)

    S. Kroening; E. Neubauer; B. Wullich; J. Aten; M. Goppelt-Struebe

    2010-01-01

    Kroening S, Neubauer E, Wullich B, Aten J, Goppelt-Struebe M. Characterization of connective tissue growth factor expression in primary cultures of human tubular epithelial cells: modulation by hypoxia. Am J Physiol Renal Physiol 298:F796-F806, 2010. First published December 23, 2009; doi:10.1152/aj

  12. Dynamic Culturing of Smooth Muscle Cells in Tubular Poly(Trimethylene Carbonate) Scaffolds for Vascular Tissue Engineering

    NARCIS (Netherlands)

    Song, Yan; Wennink, Jos W.H.; Kamphuis, Marloes M.J.; Sterk, Lotus M.T.; Vermes, Istvan; Poot, André A.; Feijen, Jan; Grijpma, Dirk W.

    2011-01-01

    Porous, tubular, flexible, and elastic poly(trimethylene carbonate) (PTMC) scaffolds (length 8 cm and inner diameter 3 mm) for vascular tissue engineering were prepared by means of a dip-coating and particulate leaching procedure. Using NaCl as porogen, scaffolds with an average pore size of 110 μm

  13. Mitochondrial reactive oxygen species-mediated NLRP3 inflammasome activation contributes to aldosterone-induced renal tubular cells injury.

    Science.gov (United States)

    Ding, Wei; Guo, Honglei; Xu, Chengyan; Wang, Bin; Zhang, Minmin; Ding, Feng

    2016-04-01

    Aldosterone (Aldo) is an independent risk factor for chronic kidney disease (CKD), and although Aldo directly induces renal tubular cell injury, the underlying mechanisms remain unclear. NLRP3 inflammasome and mitochondrial reactive oxygen species (ROS) have recently been implicated in various kinds of CKD. The present study hypothesized that mitochondrial ROS and NLRP3 inflammasome mediated Aldo-induced tubular cell injury. The NLRP3 inflammasome is induced by Aldo in a dose- and time-dependent manner, as evidenced by increased NLRP3, ASC, caspase-1, and downstream cytokines, such as interleukin (IL)-1β and IL-18. The activation of the NLRP3 inflammasome was significantly prevented by the selective mineralocorticoid receptor (MR) antagonist eplerenone (EPL) (P < 0.01). Mice harboring genetic knock-out of NLRP3 (NLRP3(-/-)) showed decreased maturation of renal IL-1β and IL-18, reduced renal tubular apoptosis, and improved renal epithelial cell phenotypic alternation, and attenuated renal function in response to Aldo-infusion. In addition, mitochondrial ROS was also increased in Aldo-stimulated HK-2 cells, as assessed by MitoSOXTM red reagent. Mito-Tempo, the mitochondria-targeted antioxidant, significantly decreased HK-2 cell apoptosis, oxidative stress, and the activation of NLRP3 inflammasome. We conclude that Aldo induces renal tubular cell injury via MR dependent, mitochondrial ROS-mediated NLRP3 inflammasome activation. PMID:27014913

  14. Mitochondrial reactive oxygen species-mediated NLRP3 inflammasome activation contributes to aldosterone-induced renal tubular cells injury

    Science.gov (United States)

    Ding, Wei; Guo, Honglei; Xu, Chengyan; Wang, Bin; Zhang, Minmin; Ding, Feng

    2016-01-01

    Aldosterone (Aldo) is an independent risk factor for chronic kidney disease (CKD), and although Aldo directly induces renal tubular cell injury, the underlying mechanisms remain unclear. NLRP3 inflammasome and mitochondrial reactive oxygen species (ROS) have recently been implicated in various kinds of CKD. The present study hypothesized that mitochondrial ROS and NLRP3 inflammasome mediated Aldo–induced tubular cell injury. The NLRP3 inflammasome is induced by Aldo in a dose- and time-dependent manner, as evidenced by increased NLRP3, ASC, caspase-1, and downstream cytokines, such as interleukin (IL)-1β and IL-18. The activation of the NLRP3 inflammasome was significantly prevented by the selective mineralocorticoid receptor (MR) antagonist eplerenone (EPL) (P < 0.01). Mice harboring genetic knock-out of NLRP3 (NLRP3−/−) showed decreased maturation of renal IL-1β and IL-18, reduced renal tubular apoptosis, and improved renal epithelial cell phenotypic alternation, and attenuated renal function in response to Aldo-infusion. In addition, mitochondrial ROS was also increased in Aldo-stimulated HK-2 cells, as assessed by MitoSOXTM red reagent. Mito-Tempo, the mitochondria-targeted antioxidant, significantly decreased HK-2 cell apoptosis, oxidative stress, and the activation of NLRP3 inflammasome. We conclude that Aldo induces renal tubular cell injury via MR dependent, mitochondrial ROS-mediated NLRP3 inflammasome activation. PMID:27014913

  15. 77 FR 34013 - Certain Oil Country Tubular Goods From the People's Republic of China: Preliminary Results of the...

    Science.gov (United States)

    2012-06-08

    ...\\ Moreover, U.S. Steel contends that financial statements will show that that surrogate financial ratios can... financial ratios.\\26\\ \\24\\ See Letter from U.S. Steel, ``Oil Country Tubular Goods from the People's... whether financial ratios reflect labor expenses that are included in other elements of the...

  16. Statistical tracking of tree-like tubular structures with efficient branching detection in 3D medical image data

    DEFF Research Database (Denmark)

    Wang, X; Heimann, T; Lo, P;

    2012-01-01

    The segmentation of tree-like tubular structures such as coronary arteries and airways is an essential step for many 3D medical imaging applications. Statistical tracking techniques for the extraction of elongated structures have received considerable attention in recent years due to their robust...

  17. Atorvastatin ameliorates contrast medium-induced renal tubular cell apoptosis in diabetic rats via suppression of Rho-kinase pathway.

    Science.gov (United States)

    Su, Jinzi; Zou, Wenbo; Cai, Wenqin; Chen, Xiuping; Wang, Fangbing; Li, Shuizhu; Ma, Wenwen; Cao, Yangming

    2014-01-15

    Contrast medium-induced acute kidney injury (CI-AKI) remains a leading cause of iatrogenic, drug-induced acute renal failure. This study aimed to investigate the protective effects of atorvastatin against renal tubular cell apoptosis in diabetic rats and the related mechanisms. CI-AKI was induced by intravenous administration of iopromide (12ml/kg) in streptozotocin-induced diabetic rats. Atorvastatin (ATO) was administered intragastrically at the dose of 5, 10 and 30mg/kg/d in different groups, respectively, for 5 days before iopromide injection. Renal function parameters, kidney histology, renal tubular cell apoptosis, the expression of apoptosis regulatory proteins, caspase-3 and Rho-associated protein kinase 1 (ROCK-1), and the phosphorylation of myosin phosphatase target subunit -1 (MYPT-1), were determined. Atorvastatin was shown to notably ameliorate contrast medium induced medullary damage, restore renal function, and suppress renal tubular apoptosis. Meanwhile, atorvastatin up-regulated the expression of Bcl-2, down-regulated the expression of Bax, caspase-3 and ROCK-1, restored the ratio of Bcl-2/Bax, and suppressed the phosphorylation of MYPT-1 in a dose-dependent manner. Thus, atorvastatin pretreatment could dose-dependently ameliorate the development of CI-AKI, which was partly attributed to its suppression of renal tubular cell apoptosis by inhibiting the Rho/ROCK pathway.

  18. Ex vivo hyperpolarized MR spectroscopy on isolated renal tubular cells: A novel technique for cell energy phenotyping

    DEFF Research Database (Denmark)

    Juul, Troels; Palm, Fredrik; Nielsen, Per Mose;

    2016-01-01

    ) C MR is suitable for cells isolated from kidney tissue, without prior cell culture. METHODS: Isolation of tubular cells from freshly excised kidney tissue and treatment with either ouabain or antimycin A was investigated with hyperpolarized MR spectroscopy on a 9.4 Tesla preclinical imaging system...

  19. Evaluation of selected martensitic stainless steels for use in downhole tubular expansion - Results of a laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Mack, Robert [Shell International E and P, b.v. Kessler Park 1, Postbus 60, 2280 AB Rijswijk (Netherlands)

    2004-07-01

    A laboratory program was performed to evaluate the potential of selected martensitic stainless steels for downhole cladding applications. The evaluation of the effects of tubular expansion on mechanical properties, defects, and resistance to environmentally assisted cracking demonstrated that some steels were acceptable for the intended application. The results were used to qualify and select the stainless steel for the intended sweet cladding applications. (authors)

  20. Design, Construction and Ocean Testing of Wave Energy Conversion System with Permanent Magnet Tubular Linear Generator

    Institute of Scientific and Technical Information of China (English)

    陈中显; 余海涛; 刘春元; 洪立玮

    2016-01-01

    In this paper, the design, construction and ocean testing of a wave energy conversion system are stud-ied. Based on the motion characteristics of double buoys in ocean waves, a wave energy conversion system with permanent magnet tubular linear generator(PMTLG)is proposed to convert ocean wave energy into electricity. The wave energy conversion system was installed in the Yellow Sea near Lianyungang, China. The ocean test re-sults indicate that it had dynamic and static performance, and obtained an expected amount of electricity. The calcu-lation result indicates the average output power was about 1,000,W, and the conversion efficiency from wave en-ergy into electricity was 1.4%,. In addition, the wireless data communication, mechanics and oceanography were also discussed.

  1. Experimental Investigation of a Vertical Tubular Desalination Unit Using Humidification Dehumidification Process

    Institute of Scientific and Technical Information of China (English)

    熊日华; 王世昌; 王志; 解利昕; 李凭力; 朱爱梅

    2005-01-01

    A vertical tubular desalination unit with shell and tube structure was built to perform humidification and dehumidification simultaneously on the tube and shell side of the column, respectively. The effects of several operating conditions on the productivity and thermal efficiency of the column were investigated. The results show that both the productivity and thermal efficiency of the column enhance with the elevation of the inlet water temperature. The flow rates of water and carrier gas both have optimal operating ranges, which are 10-30 kg·h-1 and 4-7kg·h-1 for the present column, respectively. Meanwhile, the increase of external steam flow rate will promote the productivity of the column but reduce its thermal efficiency.

  2. Two-dimensional and tubular structures of misfit compounds: Structural and electronic properties

    Directory of Open Access Journals (Sweden)

    Tommy Lorenz

    2014-11-01

    Full Text Available Misfit layer compounds are structures that consist of two sublattices differing in at least one of their lattice constants. The two different layers are stacked either an alternating or in a more complex series resulting in mono- or multi-layer misfit compounds. To date, planar and bent misfit structures, such as tubes, scrolls or nanoparticles, have been synthesized and interesting magnetic and physical properties have been observed as a result of their special structures. Based on these observations, we present an overview of such misfit systems and summarize and discuss their electronic structure as well as the interlayer bonding behaviour, which is not completely understood yet. Furthermore, a more detailed insight into the SnS–SnS2 system is given, which was the first tubular misfit compound that has been synthesized and extensively investigated.

  3. Early period of early Permian tubular cyanobacteria reef in the eastern part of south Qinling Mountains

    Institute of Scientific and Technical Information of China (English)

    巩恩普; 范嘉松

    2000-01-01

    A typical reef occurs in the eastern part of south Qinling Mountains in Sanlixia, Xun-yang, Shaanxi Province. The reef, extending in north-south direction, was built up by various kinds of calcareous tubes including Girvanella, tubular cyanobacteria and problem microbials. The bio-clastic bank, built up by algal clasts, foraminiferous, and fusulinids, formed the reef basement, on which dasyclads baffle bioclasts formed the original bafflestone at a small scale on the reef basement, and then a mass of bindstone was made up by all kinds of calcareous tubes and algae. On lateral part the reef is cryptalgal mudstone. The reef that occurred in the geosynclinal area is so familiar with one of the platforms in many respects, such as in reef structure, morphology and building mold. This indicates that building organisms have amazing adaptability and identity for building capacity in the two kinds of geotectonic background mentioned above.

  4. Early period of early Permian tubular cyanobacteria reef in the eastern part of south Qinling Mountains

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A typical reef occurs in the eastern part of south Qinling Mountains in Sanlixia, Xunyang, Shaanxi Province. The reef, extending in north-south direction, was built up by various kinds of calcareous tubes including Girvanella, tubular cyanobacteria and problem microbials. The bioclastic bank, built up by algal clasts, foraminiferous, and fusulinids, formed the reef basement, on which dasyclads baffle bioclasts formed the original bafflestone at a small scale on the reef basement, and then a mass of bindstone was made up by all kinds of calcareous tubes and algae. On lateral part the reef is cryptalgal mudstone. The reef that occurred in the geosynclinal area is so familiar with one of the platforms in many respects, such as in reef structure, morphology and building mold. This indicates that building organisms have amazing adaptability and identity for building capacity in the two kinds of geotectonic background mentioned above.

  5. The application limits of alloyed 13%Cr tubular steels for downhole duties

    Energy Technology Data Exchange (ETDEWEB)

    Cooling, P.J.; Kennani, M.B.; Martin, J.W. [BP Exploration, Sunbury on Thames (United Kingdom); Nice, P.I. [Statoil, Stavanger (Norway)

    1998-12-31

    In the past few years, a new family of materials has entered the downhole tubular market, known as the ``alloyed 13%Cr steels.`` These are a development of the conventional API 5CT grade 13%Cr steels to which alloying elements of Ni, Mo and Cu have been added, hence offering a number of advantages. In the present paper, domains of application for the 95ksi grade alloyed 13%Cr steels with respect to sour service conditions have been defined on pH vs. H{sub 2}S partial pressure plots. Corrosion properties have also been determined for two other aspects; chloride stress corrosion cracking (ClSCC) and high temperature corrosion resistance. The results have reiterated the importance of solution chemistry, pH and H{sub 2}S partial pressure in defining the corrosion properties of steels.

  6. Performance of evacuated tubular solar collectors in a residential heating and cooling system

    Science.gov (United States)

    Duff, W. S.; Loef, G. O. G.

    1981-03-01

    Operation of CSU Solar House I during the heating season of 1978-1979 and during the 1979 cooling season is discussed. The systems comprised an experimental evacuated tubular solar collector, a nonfreezing aqueous collection medium, heat exchange to an insulated conventional vertical cylindrical storage tank and to a built up rectangular insulated storage tank, heating of circulating air by solar heated water and by electric auxiliary in an off peak heat storage unit, space cooling by lithium bromide absorption chiller, and service water heating by solar exchange and electric auxiliary. The system is compared with CSU Solar Houses I, II and III. The experimental collector provides solar heating and cooling with minimum operational problems. Improved performance, particularly for cooling, resulted from the use of a very well insulated heat storage tank. Day time electric auxiliary heating is avoided by use of off peak electric heat storage.

  7. Tubular-Type Hydroturbine Performance for Variable Guide Vane Opening by CFD

    Science.gov (United States)

    Kim, Y. T.; Nam, S. H.; Cho, Y. J.; Hwang, Y. C.; Choi, Y. D.; Nam, C. D.; Lee, Y. H.

    Micro hydraulic power generation which has output of less or equal to 100kW is attracting considerable attention. This is because of its small, simple, renewable, and large amount of energy resources. By using a small hydro power generator of which main concept is based on using differential water pressures in pipe lines, energy which was initially wasted by use of a reducing valve at an end of the pipeline, is collected by a turbine in the hydro power generator. A propeller shaped hydroturbine has been used in order to make use of this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydroturbine, output power, head, and efficiency characteristics due to the guide vane opening angle are examined in detail. Moreover, influences of pressure, tangential and axial velocity distributions on turbine performance are investigated by using a commercial CFD code.

  8. On determinants of glomerular filtration rate after inhibition of proximal tubular reabsorption

    DEFF Research Database (Denmark)

    Leyssac, P P; Karlsen, F M; Holstein-Rathlou, N H;

    1994-01-01

    The carbonic anhydrase inhibitor acetazolamide (ACZ) inhibits the absolute rate of proximal reabsorption (APR), causes a reduction in glomerular filtration rate (GFR), and activates the tubuloglomerular feedback mechanism (TGF) resulting in afferent vasoconstriction. The quantitative importance...... of the afferent vasoconstriction for the reduced GFR was tested by addition of a vasodilator during continuous infusion of ACZ. Dopamine caused an increase in renal blood flow (RBF) to pre-ACZ levels. Glomerular capillary pressure (Pgc) and proximal tubular pressure (Pprox) increased in parallel (by 3.1 and 3.......0 mmHg, respectively) leaving pressure gradient (delta P) unchanged. APR, as estimated from the clearances of 51Cr-EDTA and lithium, remained unchanged. Urine flow almost doubled. GFR was only modestly reversed (pre-ACZ/ACZ/ACZ+dopamine: 100/77/83%). It is concluded that relieving the afferent...

  9. Approach for analyzing the ultimate strength of concrete filled steel tubular arch bridges with stiffening girder

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-cheng; XIE Xu; ZHANG He; CHEN Heng-zhi

    2007-01-01

    A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders isinvestigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.

  10. Novel tubular switched reluctance motor with double excitation windings: Design, modeling, and experiments

    Science.gov (United States)

    Yan, Liang; Li, Wei; Jiao, Zongxia; Chen, I.-Ming

    2015-12-01

    The space utilization of linear switched reluctance machine is relatively low, which unavoidably constrains the improvement of system output performance. The objective of this paper is to propose a novel tubular linear switched reluctance motor with double excitation windings. The employment of double excitation helps to increase the electromagnetic force of the system. Furthermore, the installation of windings on both stator and mover can make the structure more compact and increase the system force density. The design concept and operating principle are presented. Following that, the major structure parameters of the system are determined. Subsequently, electromagnetic force and reluctance are formulated analytically based on equivalent magnetic circuits, and the result is validated with numerical computation. Then, a research prototype is developed, and experiments are conducted on the system output performance. It shows that the proposed design of electric linear machine can achieve higher thrust force compared with conventional linear switched reluctance machines.

  11. Prohibitin is associated with antioxidative protection in hypoxia/reoxygenation-induced renal tubular epithelial cell injury

    Science.gov (United States)

    Zhou, Tian-Biao; Qin, Yuan-Han; Lei, Feng-Ying; Huang, Wei-Fang; Drummen, Gregor P. C.

    2013-11-01

    Prohibitin is an evolutionary conserved and pleiotropic protein that has been implicated in various cellular functions, including proliferation, tumour suppression, apoptosis, transcription, and mitochondrial protein folding. We recently demonstrated that prohibitin downregulation results in increased renal interstitial fibrosis. Here we investigated the role of oxidative stress and prohibitin expression in a hypoxia/reoxygenation injury system in renal tubular epithelial cells with lentivirus-based delivery vectors to knockdown or overexpress prohibitin. Our results show that increased prohibitin expression was negatively correlated with reactive oxygen species, malon dialdehyde, transforming-growth-factor-β1, collagen-IV, fibronectin, and apoptosis (r = -0.895, -0.764, -0.798, -0.826, -0.817, -0.735 each P mechanisms that counteract oxidative stress and extracellular matrix accumulation and therefore has an antioxidative effect.

  12. Evaluation and Model of Performance of A Tubular Solid Oxide Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    JIA Jun-xi; SHEN Sheng-qiang

    2005-01-01

    A simulation model was developed to analyze the steady state and transient operation of a tubular solid oxide fuel cell. The model covers both the electrochemical and the heat transfer models. The electrochemical model deals with the Nernst potential, ohmic polarization, activation polarization, and concentration polarization, while the heat transfer model concerns the heat transfer by conduction, convection and radiation. The numerical results show that the ohmic loss is the dominant one among the three polarizations in a cathode-supported solid oxide fuel cell and in the middle part of a solid oxide fuel cell the temperature is higher than those at both the ends. When the inlet temperature and the flow rates of the fuel and the oxidant are kept constantly, the temperature of the solid structure of the cell will increase due to the increase of power output of the cell from the initial state to the new one.

  13. Analysis of Entropy Generation for the Performance Improvement of a Tubular Solid Oxide Fuel Cell Stack

    Directory of Open Access Journals (Sweden)

    Vittorio Verda

    2009-03-01

    Full Text Available The aim of the paper is to investigate possible improvements in the design and operation of a tubular solid oxide fuel cell. To achieve this purpose, a CFD model of the cell is introduced. The model includes thermo-fluid dynamics, chemical reactions and electrochemistry. The fluid composition and mass flow rates at the inlet sections are obtained through a finite difference model of the whole stack. This model also provides boundary conditions for the radiation heat transfer. All of these conditions account for the position of each cell within the stack. The analysis of the cell performances is conducted on the basis of the entropy generation. The use of this technique makes it possible to identify the phenomena provoking the main irreversibilities, understand their causes and propose changes in the system design and operation.

  14. Late Metabolic Acidosis Caused by Renal Tubular Acidosis in Acute Salicylate Poisoning.

    Science.gov (United States)

    Sakai, Norihiro; Hirose, Yasuo; Sato, Nobuhiro; Kondo, Daisuke; Shimada, Yuko; Hori, Yasushi

    2016-01-01

    A 16-year-old man was transferred to our emergency department seven hours after ingesting 486 aspirin tablets. His blood salicylate level was 83.7 mg/dL. He was treated with fluid resuscitation and sodium bicarbonate infusion, and his condition gradually improved, with a decline in the blood salicylate level. However, eight days after admission, he again reported nausea, a venous blood gas revealed metabolic acidosis with a normal anion gap. The blood salicylate level was undetectable, and a urinalysis showed glycosuria, proteinuria and elevated beta-2 microglobulin and n-acetyl glucosamine levels, with a normal urinary pH despite the acidosis. We diagnosed him with relapse of metabolic acidosis caused by renal tubular acidosis. PMID:27181539

  15. Vibration analysis of the Second Saikai Bridge—a concrete filled tubular (CFT) arch bridge

    Science.gov (United States)

    Yoshimura, Mistuhiro; Wu, Qingxiong; Takahashi, Kazuo; Nakamura, Shozo; Furukawa, Kazuyoshi

    2006-02-01

    Concrete-filled steel tubular (CFT) arch bridges have been rapidly developing in China since 1990. Research has focused on the static behavior, thermal stress and erection technique, however, and there has been very little research of natural vibrations and dynamic responses of these bridges. Japan's first CFT arch bridge in highway bridges, the Second Saikai Bridge, is now under construction in Nagasaki Prefecture. Furthermore, this bridge has a pedestrian bridge that is suspended under the girder, which is rare. Therefore, the natural vibration properties are examined, and the influence of pedestrian bridge structure on the natural vibration of main bridge is discussed first. Response analysis under a moving vehicle and pedestrian is carried out, and the response characteristics and response level are clarified. The natural vibrations and responses are compared to those of CFT arch bridges that have been constructed in China. Results show the fine performance of both main bridge and pedestrian bridge of the Second Saikai Bridge.

  16. Multi-physics analysis of permanent magnet tubular linear motors under severe volumetric and thermal constraints

    Institute of Scientific and Technical Information of China (English)

    李方; 叶佩青; 张辉

    2016-01-01

    Permanent magnet tubular linear motors (TLMs) arranged in multiple rows and multiple columns used for a radiotherapy machine were studied. Due to severe volumetric and thermal constraints, the TLMs were at high risk of overheating. To predict the performance of the TLMs accurately, a multi-physics analysis approach was proposed. Specifically, it considered the coupling effects amongst the electromagnetic and the thermal models of the TLMs, as well as the fluid model of the surrounding air. To reduce computation cost, both the electromagnetic and the thermal models were based on lumped-parameter methods. Only a minimum set of numerical computation (computational fluid dynamics, CFD) was performed to model the complex fluid behavior. With the proposed approach, both steady state and transient state temperature distributions, thermal rating and permissible load can be predicted. The validity of this approach is verified through the experiment.

  17. Tubular Shape Fullerenes Inside Single Wall Boron Nitride Nanotubes: A Theoretical Simulation.

    Science.gov (United States)

    Ma, Fengxian; Yao, Zhen; Yao, Mingguang; Liu, Ran; Cui, Tian; Liu, Bingbing

    2016-06-01

    The orientations of fullerene molecules filled in nanotubes have important influence on the electronic properties of the formed peapods and their transformations such as polymerization under certain conditions. Here we present a investigation on the preferable orientations of tubular C70, C80 and C90 fullerenes confined inside single-walled boron nitride nanotubes (SWBNNTs) by calculating the van der Waals energy between the encapsulated molecule and the hosting nanotube. The minimum entering radius and the energetically favorable radius for encapsulating C70, C80 and C90 have been determined by the reaction energy calculation. We also show that the three studied molecules filled in SWBNNTs exhibit a transition from lying (five-fold axis) orientation to tilted orientation and then to standing orientation (two-fold axis) with increasing the tube radius. The preferable orientations of the encapsulated fullerenes are irrelevant on the tube chirality, but are dependent on the radius. PMID:27427630

  18. Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

    Science.gov (United States)

    Milcarek, Ryan J.; Wang, Kang; Falkenstein-Smith, Ryan L.; Ahn, Jeongmin

    2016-02-01

    Currently the role of fuel cells in future power generation is being examined, tested and discussed. However, implementing systems is more difficult because of sealing challenges, slow start-up and complex thermal management and fuel processing. A novel furnace system with a flame-assisted fuel cell is proposed that combines the thermal management and fuel processing systems by utilizing fuel-rich combustion. In addition, the flame-assisted fuel cell furnace is a micro-combined heat and power system, which can produce electricity for homes or businesses, providing resilience during power disruption while still providing heat. A micro-tubular solid oxide fuel cell achieves a significant performance of 430 mW cm-2 operating in a model fuel-rich exhaust stream.

  19. External Pressure Forming and Buckling Analysis of Tubular Parts with Ribs

    Institute of Scientific and Technical Information of China (English)

    Gang LIU; Xuelian YIN; Shijian YUAN

    2006-01-01

    Buckling and forming processes of tubes with varying slenderness ratio(ratio of length to diameter)under external hydraulic pressure were analyzed with three-dimensional finite element method(FEM)for studying tube external pressure forming(EPF). Buckling pressures for different tube blanks without mandrel were predicted, and an EPF of a carbon steel tube onto a mandrel with six ribs was simulated. Both thickness distribution and buckling pressure from the simulations were found to be in agreement with those from experiments. Buckling pressures are shown to be a function of the slenderness ratio. The tubular part with six ribs produced by EPF has a uniform thickness distribution, whose maximum thinning rate is only 5.9%.

  20. Finite Element Analysis and Codal Recommendations of Concrete Filled Steel Tubular Columns

    Science.gov (United States)

    Jayalekshmi, S.; Sankar Jegadesh, J. S.

    2016-03-01

    This work presents the numerical behaviour and theoretical design of axially loaded Concrete Filled Steel Tubular (CFST) columns. A numerical investigation using commercial software ANSYS is performed. The numerical models are used for the computations and the results are validated with the corresponding experimental program from the literature. It is observed that the numerical model is able to map the load deflection response of the CFST specimens. A good concurrence is also observed between the experimental and the predicted numerical results. The column strength predicted from the finite element analysis and by using the American Institute of Steel Construction and the Chinese CECS specifications are compared with the corresponding experimental results obtained from the literature. The comparative results ensured that D/t ratio plays a prominent role on the compressive behaviour of the CFST specimens. This paper quantifies the difference between the experimental and numerical results, and the ultimate load of the CFST columns estimated by various International code procedures.

  1. Numerical simulation of a novel expanded metal tubular structure for crashworthiness application

    Science.gov (United States)

    Abdelaal, A. H. A.; Tarlochan, F.

    2015-12-01

    Search for new geometries and materials that would serve in crashworthiness applications is a cumulative process. Recent studies investigated the performance of expanded metal tubes and the possible ways to enhance its energy absorption capability. The aim of this work is to investigate the crashworthiness characteristics of new concept is proposed where expanded metal tube is suited into a double-walled tube made of the same material to form one structure. The tube was then numerically tested through a verified model using ABAQUS software. Moreover, the influence of the size of the expanded metal cell was also investigated in the present study. The new concept showed an enhanced energy absorption characteristics related to the change in the mass of the tubular structure. The enhancement was related to both the change in deformation pattern, and the increase in crushed mass.

  2. Using Powder Cored Tubular Wire Technology to Enhance Electron Beam Freeform Fabricated Structures

    Science.gov (United States)

    Gonzales, Devon; Liu, Stephen; Domack, Marcia; Hafley, Robert

    2016-01-01

    Electron Beam Freeform Fabrication (EBF3) is an additive manufacturing technique, developed at NASA Langley Research Center, capable of fabricating large scale aerospace parts. Advantages of using EBF3 as opposed to conventional manufacturing methods include, decreased design-to-product time, decreased wasted material, and the ability to adapt controls to produce geometrically complex parts with properties comparable to wrought products. However, to fully exploit the potential of the EBF3 process development of materials tailored for the process is required. Powder cored tubular wire (PCTW) technology was used to modify Ti-6Al-4V and Al 6061 feedstock to enhance alloy content, refine grain size, and create a metal matrix composite in the as-solidified structures, respectively.

  3. Behavior of concrete and concrete-filled circular steel tubular stub columns at constant high temperatures

    Institute of Scientific and Technical Information of China (English)

    DING Fa-xing; YU Zhi-wu

    2006-01-01

    Based on reanalyzing test results of uniaxial compressive behavior of concrete at constant high temperatures in China,with the compressive cube strength of concrete from 20 to 80 Mpa, unified formulas for uniaxial compressive strength, elastic modulus, strain at peak uniaxial compression and mathematical expression for unaxial compressive stress-strain relations for the concrete at constant high temperatures were studied. Furthermore, the axial stress-axial strain relations between laterally confined concrete under axial compression and multiaxial stress-strain relations for steel at constant high temperatures were studied. Finally,based on continuum mechanics, the mechanics model for concentric cylinders of circular steel tube with concrete core of entire section loaded at constant high temperatures was established. Applying elasto-plastic analysis method, a FORTRAN program was developed, and the concrete-filled circular steel tubular (CFST) stub columns at constant high temperatures were analyzed. The analysis results are in agreement with the experiment ones from references.

  4. Numerical analysis of ultimate strength of concrete filled steel tubular arch bridges

    Institute of Scientific and Technical Information of China (English)

    XIE Xu; CHEN Heng-zhi; Li Hui; SONG Shi-rui

    2005-01-01

    The calculation of ultimate bearing capacity is a significant issue in the design of Concrete Filled Steel Tubular (CFST)arch bridges. Based on the space beam theory, this paper provides a calculation method for determining the ultimate strength of CFST structures. The accuracy of this method and the applicability of the stress-strain relationships were validated by comparing different existing confined concrete uniaxial constitutive relationships and experimental results. Comparison of these results indicated that this method using the confined concrete uniaxial stress-strain relationships can be used to calculate the ultimate strength and CFST behavior with satisfactory accuracy. The calculation results are stable and seldom affected by concrete constitutive relationships. The method is therefore valuable in the practice of engineering design. Finally, the ultimate strength of an arch bridge with span of 330 m was investigated by the proposed method and the nonlinear behavior was discussed.

  5. Tubular localization and expressional dynamics of aquaporins in the kidney of seawater-challenged Atlantic salmon

    DEFF Research Database (Denmark)

    Engelund, Morten Buch; Madsen, Steffen S

    2015-01-01

    in renal function from filtration towards secretion. We localized aquaporins (Aqp) in Atlantic salmon renal tubular segments by immunohistochemistry and monitored their expressional dynamics using RT-PCR and immunoblotting. Three aquaporins: Aqpa1aa, Aqp1ab and Aqp8b and two aquaglyceroporins Aqp3a and Aqp....... Aqp10b was expressed apically and along the lateral membrane. Aqp8b was mainly basolateral and Aqp1ab was located in sub-apical intracellular compartments. mRNAs of aqp8b and aqp10b were higher in FW smolts compared to FW parr, whereas the opposite was true for aqp1aa. Aqp mRNA levels changed...... in response to both SW and sham transfer. Protein levels, however, were stable for most paralogs. In conclusion, aquaporins are abundant in salmon proximal renal tubules and may participate in water secretion and thus urine modification as suggested for other vertebrates. Further studies should seek to couple...

  6. Dynamic load testing on the bearing capacity of prestressed tubular concrete piles in soft ground

    Science.gov (United States)

    Yu, Chuang; Liu, Songyu

    2008-11-01

    Dynamic load testing (DLT) is a high strain test method for assessing pile performance. The shaft capacity of a driven PTC (prestressed tubular concrete) pile in marine soft ground will vary with time after installation. The DLT method has been successfully transferred to the testing of prestressed pipe piles in marine soft clay of Lianyungang area in China. DLT is investigated to determine the ultimate bearing capacity of single pile at different period after pile installation. The ultimate bearing capacity of single pile was founded to increase more than 70% during the inventing 3 months, which demonstrate the time effect of rigid pile bearing capacity in marine soft ground. Furthermore, the skin friction and axial force along the pile shaft are presented as well, which present the load transfer mechanism of pipe pile in soft clay. It shows the economy and efficiency of DLT method compared to static load testing method.

  7. Serviceability of 13Cr tubulars in oil and gas production environments

    Energy Technology Data Exchange (ETDEWEB)

    Cayard, M.S.; Kane, R.D. [InterCorr/CL1 International, Inc., Houston, TX (United States)

    1998-12-31

    This paper reviewed the current literature concerning the serviceability of conventional and modified 13Cr tubulars in oil and gas production environments. The serviceability in sour environments was divided into the variables which affect is corrosion performance, namely system pH, chlorides, temperature and H{sub 2}S/CO{sub 2}. At low temperatures, SSC is of primary concern. At elevated temperatures (> 100 C), SSC is generally not a problem. In this regime, mass loss corrosion and localized attack dictate the serviceability. Mass loss corrosion increases with a decrease in pH and in general increase with increases in temperature, H{sub 2}S and CO{sub 2} partial pressures. Susceptibility to localized corrosion was found to be highest at intermediate temperatures in the vicinity of 150 C.

  8. Mechanical properties of human autologous tubular connective tissues (human biotubes) obtained from patients undergoing peritoneal dialysis.

    Science.gov (United States)

    Nakayama, Yasuhide; Kaneko, Yoshiyuki; Takewa, Yoshiaki; Okumura, Noriko

    2016-10-01

    Completely autologous in vivo tissue-engineered connective tissue tubes (Biotubes) have promise as arterial vascular grafts in animal implantation studies. In this clinical study of patients undergoing peritoneal dialysis (PD) (n = 11; age: 39-83 years), we evaluated human Biotubes' (h-Biotubes) mechanical properties to determine whether Biotubes with feasibility as vascular grafts could be formed in human bodies. We extracted PD catheters, embedded for 4-47 months, and obtained tubular connective tissues as h-Biotubes (internal diameter: 5 mm) from around the catheter' silicone tubular parts. h-Biotubes were composed mainly of collagen with smooth luminal surfaces. The average wall thickness was 278 ± 178 μm. No relationship was founded between the tubes' mechanical properties and patients' ages or PD catheter embedding periods statistically. However, the elastic modulus (2459 ± 970 kPa) and tensile strength (623 ± 314 g) of h-Biotubes were more than twice as great as those from animal Biotubes, formed from the same PD catheters by embedding in the beagle subcutaneous pouches for 1 month, or beagle arteries. The burst strength (6338 ± 1106 mmHg) of h-Biotubes was almost the same as that of the beagle thoracic or abdominal aorta. h-Biotubes could be formed in humans over a 4-month embedding period, and they satisfied the mechanical requirements for application as vascular grafts. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1431-1437, 2016.

  9. Renal proximal tubular cell fibronectin accumulation in response to glucose is polyol pathway dependent

    Science.gov (United States)

    Morrisey; Steadman; Williams; Phillips

    1999-06-01

    Thickening and reduplication of the tubular basement membrane has been reported as an early event in diabetic nephropathy. In the current study we have examined the polar requirements of proximal tubular cells for the D-glucose stimulated accumulation of fibronectin. We also examined the mechanism by which glucose led to accumulation of fibronectin, with particular emphasis on the polyol pathway. Incubation of confluent monolayers of LLC-PK1 cells grown on tissue culture inserts with 25 mM D-glucose on either their apical or basolateral aspect, led to fibronectin accumulation in the basolateral compartment. This reached statistical significance 24 h following apical addition of glucose (2.7 fold increase compared to 5 mM D-glucose, p = 0.007, n = 6), and 12 h after the basolateral addition of glucose (2.54 fold increase compared to 5 mM D-glucose, p = 0.02, n = 6). The increase in fibronectin concentration in response to glucose was inhibited by the aldose reductase inhibitor sorbinil. At a dose of 100&mgr;M sorbinil there was 59% inhibition of fibronectin accumulation in response to glucose, 48 h after the addition of the inhibitor (4.76 +/- 1.4 vs 11.53 +/- 1.41, mean +/- SD, p = 0.01, n = 3). Exposure of cells to glucose at either their apical or basolateral aspect lead to accumulation of intracellular glucose and polyol pathway activation, as assessed by sorbitol accumulation. Accumulation of intracellular glucose and hence subsequent polyol pathway activation occurred independently of transport of glucose by either apical sodium linked glucose transporter (SLGT) or basolateral GLUT 1. The data demonstrate that fibronectin generation in response to glucose was non-polar in terms application of glucose, but polar in terms of fibronectin accumulation. Furthermore modulation of fibronectin was mediated by polyol pathway activation, and more specifically related to the metabolism of sorbitol to fructose. PMID:10354307

  10. Chronic administration of AM251 improves albuminuria and renal tubular structure in obese rats.

    Science.gov (United States)

    Jenkin, Kayte A; O'Keefe, Lannie; Simcocks, Anna C; Grinfeld, Esther; Mathai, Michael L; McAinch, Andrew J; Hryciw, Deanne H

    2015-05-01

    Modulation of the endocannabinoid system as an anti-obesity therapeutic is well established; however, the direct effects of cannabinoid receptor 1 (CB1) antagonism on renal function and structure in a model of diet-induced obesity (DIO) are unknown. The aim of this study was to characterise the renal effects of the CB1 antagonist AM251 in a model of DIO. Male Sprague-Dawley rats were fed a low- or high-fat diet (HFD: 40% digestible energy from lipids) for 10 weeks to elicit DIO (n=9). In a different cohort, rats were fed a HFD for 15 weeks. After 9 weeks consuming a HFD, rats were injected daily for 6 weeks with 3 mg/kg AM251 (n=9) or saline via i.p. injection (n=9). After 10 weeks consuming a HFD, CB1 and megalin protein expression were significantly increased in the kidneys of obese rats. Antagonism of CB1 with AM251 significantly reduced weight gain, systolic blood pressure, plasma leptin, and reduced albuminuria and plasma creatinine levels in obese rats. Importantly, there was a significant reduction in tubular cross-section diameter in the obese rats treated with AM251. An improvement in albuminuria was likely due to the reduction in tubular size, reduced leptinaemia and maintenance of megalin expression levels. In obese rats, AM251 did not alter diastolic blood pressure, sodium excretion, creatinine clearance or expression of the fibrotic proteins VEGFA, TGFB1 and collagen IV in the kidney. This study demonstrates that treatment with CB1 antagonist AM251 improves renal outcomes in obese rats. PMID:25804605

  11. The small GTPase Cdc42 is necessary for primary ciliogenesis in renal tubular epithelial cells.

    Science.gov (United States)

    Zuo, Xiaofeng; Fogelgren, Ben; Lipschutz, Joshua H

    2011-06-24

    Primary cilia are found on many epithelial cell types, including renal tubular epithelial cells, where they participate in flow sensing. Disruption of cilia function has been linked to the pathogenesis of polycystic kidney disease. We demonstrated previously that the exocyst, a highly conserved eight-protein membrane trafficking complex, localizes to primary cilia of renal tubular epithelial cells, is required for ciliogenesis, biochemically and genetically interacts with polycystin-2 (the protein product of the polycystic kidney disease 2 gene), and, when disrupted, results in MAPK pathway activation both in vitro and in vivo. The small GTPase Cdc42 is a candidate for regulation of the exocyst at the primary cilium. Here, we demonstrate that Cdc42 biochemically interacts with Sec10, a crucial component of the exocyst complex, and that Cdc42 colocalizes with Sec10 at the primary cilium. Expression of dominant negative Cdc42 and shRNA-mediated knockdown of both Cdc42 and Tuba, a Cdc42 guanine nucleotide exchange factor, inhibit ciliogenesis in Madin-Darby canine kidney cells. Furthermore, exocyst Sec8 and polycystin-2 no longer localize to primary cilia or the ciliary region following Cdc42 and Tuba knockdown. We also show that Sec10 directly interacts with Par6, a member of the Par complex that itself directly interacts with Cdc42. Finally, we show that Cdc42 knockdown results in activation of the MAPK pathway, something observed in cells with dysfunctional primary cilia. These data support a model in which Cdc42 localizes the exocyst to the primary cilium, whereupon the exocyst then targets and docks vesicles carrying proteins necessary for ciliogenesis.

  12. The Small GTPase Cdc42 Is Necessary for Primary Ciliogenesis in Renal Tubular Epithelial Cells*

    Science.gov (United States)

    Zuo, Xiaofeng; Fogelgren, Ben; Lipschutz, Joshua H.

    2011-01-01

    Primary cilia are found on many epithelial cell types, including renal tubular epithelial cells, where they participate in flow sensing. Disruption of cilia function has been linked to the pathogenesis of polycystic kidney disease. We demonstrated previously that the exocyst, a highly conserved eight-protein membrane trafficking complex, localizes to primary cilia of renal tubular epithelial cells, is required for ciliogenesis, biochemically and genetically interacts with polycystin-2 (the protein product of the polycystic kidney disease 2 gene), and, when disrupted, results in MAPK pathway activation both in vitro and in vivo. The small GTPase Cdc42 is a candidate for regulation of the exocyst at the primary cilium. Here, we demonstrate that Cdc42 biochemically interacts with Sec10, a crucial component of the exocyst complex, and that Cdc42 colocalizes with Sec10 at the primary cilium. Expression of dominant negative Cdc42 and shRNA-mediated knockdown of both Cdc42 and Tuba, a Cdc42 guanine nucleotide exchange factor, inhibit ciliogenesis in Madin-Darby canine kidney cells. Furthermore, exocyst Sec8 and polycystin-2 no longer localize to primary cilia or the ciliary region following Cdc42 and Tuba knockdown. We also show that Sec10 directly interacts with Par6, a member of the Par complex that itself directly interacts with Cdc42. Finally, we show that Cdc42 knockdown results in activation of the MAPK pathway, something observed in cells with dysfunctional primary cilia. These data support a model in which Cdc42 localizes the exocyst to the primary cilium, whereupon the exocyst then targets and docks vesicles carrying proteins necessary for ciliogenesis. PMID:21543338

  13. Proximal glomerulo-tubular balance in patients with type 1 (insulin-dependent) diabetes mellitus.

    Science.gov (United States)

    Brøchner-Mortensen, J; Støckel, M; Sørensen, P J; Nielsen, A H; Ditzel, J

    1984-08-01

    To evaluate the glomerulo-tubular balance of sodium and water in the proximal tubules of diabetic patients with elevated glomerular filtration rate, the renal plasma clearance of lithium and the glomerular filtration rate (51Cr-EDTA plasma clearance) were determined simultaneously in 11 ambulatory Type 1 (insulin-dependent) diabetic patients (aged 25-35 years) with no evidence of diabetic nephropathy and in 10 age-matched healthy subjects. The renal plasma clearance of lithium, which is a measure of flow from the proximal tubule into the thin descending limb of the loop of Henle, did not differ between diabetic and control subjects (28.9 +/- 4.0 versus 28.3 +/- 5.1 ml/min per 1.73 m2 surface area, mean +/- SD), whereas the glomerular filtration rate in the diabetic patients was significantly higher than in the control subjects (136 +/- 10.2 versus 108 +/- 13.6 ml/min per 1.73 m2, p less than 0.001). The same held true for the fractional reabsorption rate in the proximal tubules (78.7 +/- 3.2 versus 73.6 +/- 4.9%, p less than 0.02). The results indicate that the elevation of the glomerular filtration rate in diabetic patients is associated with a parallel increase in the proximal reabsorption rate. This type of glomerulo-tubular balance implies that the flow of water and flux of sodium to the segments distal to the proximal tubule are kept constant during variations in the glomerular filtration rate.

  14. Adsorption and desorption of Cd(II) onto titanate nanotubes and efficient regeneration of tubular structures

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting; Liu, Wen; Xu, Nan [Shenzhen Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055 (China); Ni, Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

    2013-04-15

    Highlights: ► Satisfactory reuse of TNTs due to easy regeneration of tubular structures. ► TNTs regeneration using only 2% of NaOH needed for virgin TNTs preparation. ► Excellent regeneration attributed to steady TNTs skeleton and complex form of TNTs-OCd{sup +}OH{sup −} onto adsorbed TNTs. -- Abstract: Efficient regeneration of desorbed titanate nanotubes (TNTs) was investigated with cycled Cd(II) adsorption and desorption processes. After desorption of Cd (II) from TNTs using 0.1 M HNO{sub 3}, regeneration could be simply achieved with only 0.2 M NaOH at ambient temperature, i.e. 2% of the NaOH needed for virgin TNTs preparation at 130 °C. The regenerated TNTs displayed similar adsorption capacity of Cd(II) even after six recycles, while significant reduction could be detected for desorbed TNTs without regeneration. The virgin TNTs, absorbed TNTs, desorbed TNTs and regenerated TNTs were systematically characterized. As results, the ion-exchange mechanism with Na{sup +} in TNTs was convinced with obvious change of -TiO(ONa){sub 2} by FTIR spectroscopy. The easy recovery of the damaged tubular structures proved by TEM and XRD was ascribed to asymmetric distribution of H{sup +} and Na{sup +} on the surface side and interlayer region of TNTs. More importantly, the cost-effective regeneration was found possibly related to complex form of TNTs-OCd{sup +}OH{sup −} onto the adsorbed TNTs, which was identified with help of X-ray photoelectron spectroscopy, and further indicated due to high relevance to an unexpected mole ratio of 1:1 between exchanged Na{sup +} and absorbed Cd(II)

  15. Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A new finding of tubular array of 10–20 μm in length and 1–2 μm in thickness of gel polymer electrolyte (GPE) having 2.2 × 10−3 S cm−1 conductivity is reported. • Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. • GPE based supercapacitor demonstrates high capacitance of 186 F g−1. • Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. • Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. -- Abstract: A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO4 as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10−3 S cm−1 and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g−1 using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge–discharge study of supercapacitor indicated that the device has good stability, high energy density and power density

  16. Mucinous Tubular and Spindle Cell Carcinoma of Kidney and Problems in Diagnosis

    Directory of Open Access Journals (Sweden)

    Banu SARSIK

    2011-05-01

    Full Text Available Objective: Mucinous tubular and spindle cell carcinomas (MTSCC's are recently described rare type of renal cell carcinoma (RCC. MTSCC's are characterized by small, elongated tubules lined by cuboidal cells and/or cords of spindled cells separated by pale mucinous stroma. They have morphological similarities to papillary RCC (papRCC. We evaluated the importance of the immunohistochemical features in the differential diagnosis of MTSCC and papRCC.Material and Method: We re-evaluated 9 cases of MTSCC diagnosed between 2004 and 2010 and compared 10 cases of papRCC. All tumors were stained with alpha-methylacyl-CoA racemase (AMACR, cytokeratin 7 (CK7, CK19, renal cell carcinoma marker (RCC Ma, CD10 and kidney specific cadherin (KspCad.Results: A total of 6/9 cases were considered classical. Two of 9 MTSCC's were classified as “mucin-poor”. Foamy macrophages were identified in 4 cases. The immunoreactivity in MTSCC was AMACR 100%, CK7 100%, CK19 100%, RCC Ma 50%, CD10 11%, and KspCad 38% while the values for papRCC were AMACR 100%, CK7 90%, CK19 100%, RCC Ma 100%, CD10 80%, and KspCad 0%.Conclusion: MTSCCs may include little mucin and show a marked predominance of either of its principal morphological components. They may mimic other forms of RCC. Pathologists should be aware of the histological spectrum of MTSCCs to ensure an accurate diagnosis. Careful attention to the presence of a spindle cell population may be helpful in the differential diagnosis in tumors with predominant compact tubular growth. Immunohistochemical stains for papRCC are also expressed in MTSCC, but strong CD10 expression may not favor MTSCC.

  17. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  18. Single stage dorsal inlay buccal mucosal graft with tubularized incised urethral plate technique for hypospadias reoperations

    Institute of Scientific and Technical Information of China (English)

    Wei-Jing Ye; Ping Ping; Yi-Dong Liu; Zheng Li; Yi-Ran Huang

    2008-01-01

    Aim: To report the experience with single stage dorsal inlay buccal mucosal grafts using the Snodgrass technique for complex redo cases. Methods: From May 2004 to December 2005, a total of 53 patients aged from 3 to 34 years old(average 11.62 ± 7.18 years) with failed previous hypospadias surgery were included in the present study. Indica- tions included urethral strictures and repair breakdown. The unhealthy urethra was unroofed from the meatus in the ventral midline, a buccal mucosal graft was inlayed between the incised urethral plate and fixed to the corporacavemosa. The neourethra was tubularized, and covered with subcutaneous (dartos) tissue and penile skin. Glanuloplasty was also performed in all cases. Outcome analysis included clinical follow-up, and endoscopy in 2 selected cases. Results: The buccal mucosal graft was 3.0-7.5 cm in length and 0.7-2.0 cm in width. All patients required glanuloplasty, with buccal mucosal grafts extended to the tip of the glans. After a follow-up of 14-30 months (mean 22.6 months), the total complication rate was 15.1%, with five cases of fistula and three cases of stricture. Conclusion: Inlaying dorsal buccal mucosal grafts applying the Snodgrass technique is a reliable method for creating a substitute urethral plate for tubularization. The recurrent rate of urethral stricture and fistula is at an acceptable level for redo cases. This approach represents an effective, simple and safe option for reoperations. (Asain J Androl 2008 Jul; 10: 682- 686)

  19. Testing of and model development for double-walled thermal tubular

    Energy Technology Data Exchange (ETDEWEB)

    Satchwell, R.M.; Johnson, L.A. Jr.

    1992-08-01

    Insulated tubular products have become essential for use in steam injection projects. In a steam injection project, steam is created at the surface by either steam boilers or generators. During this process, steam travels from a boiler through surface lines to the wellhead, down the wellbore to the sandface, and into the reservoir. For some projects to be an economic success, cost must be reduced and oil recoveries must be increased by reducing heat losses in the wellbore. With reduced heats losses, steam generation costs are lowered and higher quality steam can be injected into the formation. To address this need, work under this project consisted of the design and construction of a thermal flow loop, testing a double-walled tubular product that was manufactured by Inter-Mountain Pipe Company, and the development and verification of a thermal hydraulic numerical simulator for steam injection. Four different experimental configurations of the double-walled pipe were tested. These configurations included: (1) bare pipe case, (2) bare pipe case with an applied annular vacuum, (3) insulated annular pipe case, and (4) insulated annular pipe case with an applied annular vacuum. Both the pipe body and coupling were tested with each configuration. The results of the experimental tests showed that the Inter-Mountain Pipe Company double-walled pipe body achieved a 98 percent reduction in heat loss when insulation was applied to the annular portion of the pipe. The application of insulation to the annular portion of the coupling reduced the heat losses by only 6 percent. In tests that specified the use of a vacuum in the annular portion of the pipe, leaks were detected and the vacuum could not be held.

  20. Transcriptomic changes in human renal proximal tubular cells revealed under hypoxic conditions by RNA sequencing.

    Science.gov (United States)

    Yu, Wenmin; Li, Yiping; Wang, Zhi; Liu, Lei; Liu, Jing; Ding, Fengan; Zhang, Xiaoyi; Cheng, Zhengyuan; Chen, Pingsheng; Dou, Jun

    2016-09-01

    Chronic hypoxia often occurs among patients with chronic kidney disease (CKD). Renal proximal tubular cells may be the primary target of a hypoxic insult. However, the underlying transcriptional mechanisms remain undefined. In this study, we revealed the global changes in gene expression in HK‑2 human renal proximal tubular cells under hypoxic and normoxic conditions. We analyzed the transcriptome of HK‑2 cells exposed to hypoxia for 24 h using RNA sequencing. A total of 279 differentially expressed genes was examined, as these genes could potentially explain the differences in HK‑2 cells between hypoxic and normoxic conditions. Moreover, 17 genes were validated by qPCR, and the results were highly concordant with the RNA seqencing results. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to better understand the functions of these differentially expressed genes. The upregulated genes appeared to be significantly enriched in the pathyway of extracellular matrix (ECM)-receptor interaction, and in paticular, the pathway of renal cell carcinoma was upregulated under hypoxic conditions. The downregulated genes were enriched in the signaling pathway related to antigen processing and presentation; however, the pathway of glutathione metabolism was downregulated. Our analysis revealed numerous novel transcripts and alternative splicing events. Simultaneously, we also identified a large number of single nucleotide polymorphisms, which will be a rich resource for future marker development. On the whole, our data indicate that transcriptome analysis provides valuable information for a more in depth understanding of the molecular mechanisms in CKD and renal cell carcinoma. PMID:27432315