85 research outputs found

    Durabilidad de construcciones de suelo-cemento reforzadas con acero

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    Composición bromatológica de la carne de conejos suplementados con mataratón y cachaza de palma aceitera

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    RESUMENObjetivo. Evaluar comparativamente el efecto de la suplementación del alimento balanceado comercial (ABC) con follaje de mataratón (Gliricidia sepium) y cachaza de palma aceitera (Elaeis guineensis) en la composición bromatológica de la carne de conejo. Materiales y métodos. Las muestras de carne estudiadas en el presente trabajo, provienen de una investigación previa con un diseño experimental de bloques al azar con tres tratamientos (dietas) y tres repeticiones (bloques) con muestreo de tres réplicas por repetición, donde se utilizaron 27 conejos machos mestizos durante el período postdestete divididos en tres tratamientos: uno control (T0), alimentados sólo con ABC, y dos suplementados con mataratón y cachaza de palma aceitera en proporciones de 30 y 10% (T1), y 10 y 30% (T2), respectivamente, a manera de comparar el efecto de las dietas en el valor nutricional. Resultados. Las muestras de carne provenientes de los diferentes animales en tratamiento, se evaluaron encontrando que la suplementación no afectó significativamente la composición bromatológica (p>0.05) para el contenido de humedad (70.77 a 72.42%), proteínas (19.08 a 20.34%), cenizas (1.53 a 1.68%) y lípidos (6.48 a 7.23%); indicando que indistintamente de la dieta empleada, suplementando el ABC con mataratón/fibra de palma o no, las carnes de conejo obtenidas son nutricionalmente idénticas como alimento. Conclusiones. Con base en los resultados, se sugiere que el follaje de mataratón y la fibra de palma aceitera podrían constituir una alternativa como recursos agronómicos tropicales en la producción de carne de conejo para el consumo human

    Evaluación de la durabilidad de bloques de tierra-cemento-sisal armado, al someterlos a la acción de iones cloruros

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    One of the primary shortcomings of adobe, a dried mudblock stabilized with sisal hemp and cement widely used across all of Latin America, is its dimensional instability when exposed to water or aggressive environments. The present paper evaluates the electrochemical performance of reinforced adobe block after 1,000 days of exposure to a simulated marine environment. The specimens used were adobe blocks internally reinforced with 3/8-inch steel bars. The specimens were watered every two weeks: one group with potable water to simulate a natural urban environment and the other with a 3% sodium chloride solution to simulate a marine environment.Chloride penetration in powder extracted from the specimens was determined using the Mohr method. Electrochemical measurements included Gecor 6 electric potential(Eº) and corrosion intensity (icorr) readings. The final conclusion drawn from an analysis of the results was that in all cases the amount of free chlorides present sufficed to depassivate reinforcing steel and that the system component providing the most effective protection was the rough casting mortar. Consequently, this type of adobe mixes is not recommended for use in marine or industrial environments.La tierra-cemento-sisal es un material cuyo uso se encuentra muy difundido en toda Latinoamérica, entre sus principales limitaciones está la inestabilidad volumétrica ante el agua y ambientes agresivos. Por tal motivo, en este trabajo se evaluó el comportamiento electroquímico de bloques de tierra-cemento-sisal armado expuestos durante 1.000 días a un ambiente marino simulado. Las probetas utilizadas fueron bloques de tierra-cemento-sisal incorporándole internamente barras de acero de 3/8 de pulg. Las probetas se sometieron a un rociado quincenal: las de ambiente natural urbano con agua potable y las de ambiente marino simulado con una solución al 3% de cloruro de sodio. La penetración de cloruros se determinó extrayendo polvillo y siguiendo el método de Mohr. Para los ensayos electroquímicos se usó el corrosímetro Gecor 6, midiendo el potencialeléctrico (E°) y la intensidad de corrosión (icorr). Finalmente, se procedió al análisis y evaluación de los resultados, concluyendo que en todos los casos la cantidad de cloruros libres presentes es suficiente para despasivar el acero de refuerzo, verificando que en el sistema el elemento que más protege es el mortero de enfoscado, por lo tanto, construcciones con este tipo de mezclas de tierra-cemento-sisal no son recomendables en zonas marinas o industriales

    BALR-6 regulates cell growth and cell survival in B-lymphoblastic leukemia

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    BackgroundA new class of non-coding RNAs, known as long non-coding RNAs (lncRNAs), has been recently described. These lncRNAs are implicated to play pivotal roles in various molecular processes, including development and oncogenesis. Gene expression profiling of human B-ALL samples showed differential lncRNA expression in samples with particular cytogenetic abnormalities. One of the most promising lncRNAs identified, designated B-ALL associated long RNA-6 (BALR-6), had the highest expression in patient samples carrying the MLL rearrangement, and is the focus of this study.ResultsHere, we performed a series of experiments to define the function of BALR-6, including several novel splice forms that we identified. Functionally, siRNA-mediated knockdown of BALR-6 in human B-ALL cell lines caused reduced cell proliferation and increased cell death. Conversely, overexpression of BALR-6 isoforms in both human and mouse cell lines caused increased proliferation and decreased apoptosis. Overexpression of BALR-6 in murine bone marrow transplantation experiments caused a significant increase in early hematopoietic progenitor populations, suggesting that its dysregulation may cause developmental changes. Notably, the knockdown of BALR-6 resulted in global dysregulation of gene expression. The gene set was enriched for leukemia-associated genes, as well as for the transcriptome regulated by Specificity Protein 1 (SP1). We confirmed changes in the expression of SP1, as well as its known interactor and downstream target CREB1. Luciferase reporter assays demonstrated an enhancement of SP1-mediated transcription in the presence of BALR-6. These data provide a putative mechanism for regulation by BALR-6 in B-ALL.ConclusionsOur findings support a role for the novel lncRNA BALR-6 in promoting cell survival in B-ALL. Furthermore, this lncRNA influences gene expression in B-ALL in a manner consistent with a function in transcriptional regulation. Specifically, our findings suggest that BALR-6 expression regulates the transcriptome downstream of SP1, and that this may underlie the function of BALR-6 in B-ALL

    TCR signal strength controls thymic differentiation of discrete proinflammatory gamma delta T cell subsets

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    The mouse thymus produces discrete gd T cell subsets that make either interferon-g (IFN-g) or interleukin 17 (IL-17), but the role of the T cell antigen receptor (TCR) in this developmental process remains controversial. Here we show that Cd3g+/− Cd3d+/− (CD3 double-haploinsufficient (CD3DH)) mice have reduced TCR expression and signaling strength on gd T cells. CD3DH mice had normal numbers and phenotypes of ab thymocyte subsets, but impaired differentiation of fetal Vg6+ (but not Vg4+) IL-17- producing gd T cells and a marked depletion of IFN-g-producing CD122+ NK1.1+ gd T cells throughout ontogeny. Adult CD3DH mice showed reduced peripheral IFN-g+ gd T cells and were resistant to experimental cerebral malaria. Thus, TCR signal strength within specific thymic developmental windows is a major determinant of the generation of proinflammatory gd T cell subsets and their impact on pathophysiology

    Neuroblastoma RAS viral oncogene homolog (N-RAS) deficiency aggravates liver injury and fibrosis.

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    Progressive hepatic damage and fibrosis are major features of chronic liver diseases of different etiology, yet the underlying molecular mechanisms remain to be fully defined. N-RAS, a member of the RAS family of small guanine nucleotide-binding proteins also encompassing the highly homologous H-RAS and K-RAS isoforms, was previously reported to modulate cell death and renal fibrosis; however, its role in liver damage and fibrogenesis remains unknown. Here, we approached this question by using N-RAS deficient (N-RAS-/-) mice and two experimental models of liver injury and fibrosis, namely carbon tetrachloride (CCl4) intoxication and bile duct ligation (BDL). In wild-type (N-RAS+/+) mice both hepatotoxic procedures augmented N-RAS expression in the liver. Compared to N-RAS+/+ counterparts, N-RAS-/- mice subjected to either CCl4 or BDL showed exacerbated liver injury and fibrosis, which was associated with enhanced hepatic stellate cell (HSC) activation and leukocyte infiltration in the damaged liver. At the molecular level, after CCl4 or BDL, N-RAS-/- livers exhibited augmented expression of necroptotic death markers along with JNK1/2 hyperactivation. In line with this, N-RAS ablation in a human hepatocytic cell line resulted in enhanced activation of JNK and necroptosis mediators in response to cell death stimuli. Of note, loss of hepatic N-RAS expression was characteristic of chronic liver disease patients with fibrosis. Collectively, our study unveils a novel role for N-RAS as a negative controller of the progression of liver injury and fibrogenesis, by critically downregulating signaling pathways leading to hepatocyte necroptosis. Furthermore, it suggests that N-RAS may be of potential clinical value as prognostic biomarker of progressive fibrotic liver damage, or as a novel therapeutic target for the treatment of chronic liver disease
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