183 research outputs found

    Relationships of low back outcomes to internal spinal load: a prospective cohort study of professional drivers

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    Purpose \u2013 To investigate the relationships between low back symptoms and alternative measures of external dose and internal spinal dose in professional drivers exposed to whole body vibration (WBV). Methods \u2013 The occurrence of low back symptoms were investigated in a cohort of 537 drivers over a two-year follow up period. Low back pain (LBP), individual characteristics, and work-related risk factors were investigated with a structured questionnaire. Exposure to WBV was evaluated by means of measures of external dose (daily vibration exposure in terms of either equivalent continuous acceleration over an eight-hour period (A(8)) or vibration dose value according to the EU Directive on mechanical vibration) and measures of internal lumbar load (daily compressive dose Sed and risk factor R according to ISO/CD 2631-5 2014). Results \u2013 In the drivers\u2019 cohort, the cumulative incidence of 12-month low back outcomes was 16.8% for LBP, 9.3% for chronic LBP, and 21.8% for sciatic pain. The measures of internal spinal load were better predictors of the occurrence of low back symptoms than the measures of daily vibration exposure. A two-fold increase in the risk estimates for low back outcomes was found in the upper quartile of the R factor (0.41-0.72 units) compared to the lower one (0.07-0.19 units). Conclusions \u2013 In this prospective cohort study, measures of internal spinal dose performed better than measures of daily vibration exposure (external dose) for the prediction of low back outcomes in professional drivers. The ISO boundary values of the risk factor R for low and high probabilities of adverse health effects on the lumbar spine tend to underestimate the health risk in professional drivers

    Reciclado de hormigón fresco mediante el uso de adición pelletizante

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    El retorno del hormigón fresco a la planta de elaboración es un problema económico y medioambiental. Aproximadamente el 2% de la producción de hormigón regresa a la planta y, en la mayoría de los casos, se elimina en gran medida como material de desecho. La producción de bloques, agregados triturados o la separación de sus componentes son algunas de las alternativas informadas para su reciclado. Recientemente se desarrolló una nueva tecnología basada en una adición en polvo de dos componentes que permite que el hormigón fresco se convierta fácilmente en un agregado artificial que puede reincorporarse a la producción de hormigón. En este trabajo se estudiaron las propiedades de los agregados pelletizados (AP) obtenidos a partir de dos formulaciones de hormigón con diferente tamaño máximo nominal de agregados naturales (AN). Asimismo, se evaluaron mezclas de hormigón que tuvieron diferentes niveles de reemplazo de AN por AP en su dosificación. En las formulaciones con sustitución parcial de AN por AP se observó una reducción de alrededor del 20% en la resistencia a la compresión respecto a la muestra control, incluso para porcentajes de sustitución muy elevados (60%). A pesar de la disminución, los hormigones basados en AP cumplen en todos los casos con los requisitos de resistencia y permiten revalorizar un residuo de la industria y cuidar el medio ambiente.Returned fresh mix concrete to the processing plant is an economic and environmental problem. About 2% of concrete production returns to the plant and, in most cases, is largely disposed of as waste material. The production of blocks, crushed aggregates or the separation of their main components are some of the alternatives reported for recycling. Recently, a new technology based on two-component powder additive has been developed, allowing the fresh returned concrete to be easily converted into an artificial aggregate, which can be incorporated into the production of concrete. In this paper, the properties of pelletized aggregates (AP) obtained from two concrete formulations with different maximum nominal natural aggregate size (AN) were studied. Also, concrete mixtures that had different levels of replacement of AN by AP in the formulation were evaluated. In the formulations with partial replacement of AN by AP, a 20% reduction in the compressive strength was observed compared to the control sample, even for very high percentages of substitution (60%). Despite the decrease, AP-based concretes comply in all cases with the resistance requirements and allow to revalue an industrial waste and take care of the environment.Fil: Schust, C.. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Ramos, M.. Coarco S.A; ArgentinaFil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

    Reciclado de hormigón fresco mediante el uso de adición pelletizante

    Get PDF
    El retorno del hormigón fresco a la planta de elaboración es un problema económico y medioambiental. Aproximadamente el 2% de la producción de hormigón regresa a la planta y, en la mayoría de los casos, se elimina en gran medida como material de desecho. La producción de bloques, agregados triturados o la separación de sus componentes son algunas de las alternativas informadas para su reciclado. Recientemente se desarrolló una nueva tecnología basada en una adición en polvo de dos componentes que permite que el hormigón fresco se convierta fácilmente en un agregado artificial que puede reincorporarse a la producción de hormigón. En este trabajo se estudiaron las propiedades de los agregados pelletizados (AP) obtenidos a partir de dos formulaciones de hormigón con diferente tamaño máximo nominal de agregados naturales (AN). Asimismo, se evaluaron mezclas de hormigón que tuvieron diferentes niveles de reemplazo de AN por AP en su dosificación. En las formulaciones con sustitución parcial de AN por AP se observó una reducción de alrededor del 20% en la resistencia a la compresión respecto a la muestra control, incluso para porcentajes de sustitución muy elevados (60%). A pesar de la disminución, los hormigones basados en AP cumplen en todos los casos con los requisitos de resistencia y permiten revalorizar un residuo de la industria y cuidar el medio ambiente.Returned fresh mix concrete to the processing plant is an economic and environmental problem. About 2% of concrete production returns to the plant and, in most cases, is largely disposed of as waste material. The production of blocks, crushed aggregates or the separation of their main components are some of the alternatives reported for recycling. Recently, a new technology based on two-component powder additive has been developed, allowing the fresh returned concrete to be easily converted into an artificial aggregate, which can be incorporated into the production of concrete. In this paper, the properties of pelletized aggregates (AP) obtained from two concrete formulations with different maximum nominal natural aggregate size (AN) were studied. Also, concrete mixtures that had different levels of replacement of AN by AP in the formulation were evaluated. In the formulations with partial replacement of AN by AP, a 20% reduction in the compressive strength was observed compared to the control sample, even for very high percentages of substitution (60%). Despite the decrease, AP-based concretes comply in all cases with the resistance requirements and allow to revalue an industrial waste and take care of the environment.Fil: Schust, C.. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Ramos, M.. Coarco S.A; ArgentinaFil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

    Diagnostic of animal brucellosis. Implementation of new technologies

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    Brucellosis is a contagious infectious disease caused by bacteria of the genus Brucella that affects human health by direct contagion with placentas, fetuses or uterine secretions or by consuming contaminated milk and its derivatives. Brucellosis affects animal health, generally causing abortions in most domestic species, and also generating a negative economic impact on the livestock industry due to losses caused by the decrease in meat and milk production and a decrease in the resale value of infected animals. The transmission of the disease in any of the affected species is done during the delivery or abortion of infected animals. Abortion generally occurs at more than half the gestation and the number of brucelas eliminated in this act is the main source of infection. In Argentina, for example, there is a national program for the control and eradication of bovine brucellosis that uses BPA as a diagnostic technique, as a sieve, Wright's tube slow motion and 2 mercaptoethanol (2ME) as confirmatory and complement fixation. as defining are those established for the control and eradication of bovine brucellosis

    Vulnerability of primitive human placental trophoblast to Zika virus

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    Infection of pregnant women by Asian lineage strains of Zika virus (ZIKV) has been linked to brain abnormalities in their infants, yet it is uncertain when during pregnancy the human conceptus is most vulnerable to the virus. We have examined two models to study susceptibility of human placental trophoblast to ZIKV: cytotrophoblast and syncytiotrophoblast derived from placental villi at term and colonies of trophoblast differentiated from embryonic stem cells (ESC). The latter appear to be analogous to the primitive placenta formed during implantation. The cells from term placentas, which resist infection, do not express genes encoding most attachment factors implicated in ZIKV entry but do express many genes associated with antiviral defense. By contrast, the ESC-derived trophoblasts possess a wide range of attachment factors for ZIKV entry and lack components of a robust antiviral response system. These cells, particularly areas of syncytiotrophoblast within the colonies, quickly become infected, produce infectious virus and undergo lysis within 48 h after exposure to low titers (multiplicity of infection > 0.07) of an African lineage strain (MR766 Uganda: ZIKVU) considered to be benign with regards to effects on fetal development. Unexpectedly, lytic effects required significantly higher titers of the presumed more virulent FSS13025 Cambodia (ZIKVC). Our data suggest that the developing fetus might be most vulnerable to ZIKV early in the first trimester before a protective zone of mature villous trophoblast has been established. Additionally, MR766 is highly trophic toward primitive trophoblast, which may put the early conceptus of an infected mother at high risk for destruction

    Identification of novel small molecules that inhibit STAT3-dependent transcription and function

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    Activation of Signal Transducer and Activator of Transcription 3 (STAT3) has been linked to several processes that are critical for oncogenic transformation, cancer progression, cancer cell proliferation, survival, drug resistance and metastasis. Inhibition of STAT3 signaling has shown a striking ability to inhibit cancer cell growth and therefore, STAT3 has become a promising target for anti-cancer drug development. The aim of this study was to identify novel inhibitors of STAT-dependent gene transcription. A cellular reporter-based system for monitoring STAT3 transcriptional activity was developed which was suitable for high-throughput screening (Z’ = 0,8). This system was used to screen a library of 28,000 compounds (the ENAMINE Drug-Like Diversity Set). Following counter-screenings and toxicity studies, we identified four hit compounds that were subjected to detailed biological characterization. Of the four hits, KI16 stood out as the most promising compound, inhibiting STAT3 phosphorylation and transcriptional activity in response to IL6 stimulation. In silico docking studies showed that KI16 had favorable interactions with the STAT3 SH2 domain, however, no inhibitory activity could be observed in the STAT3 fluorescence polarization assay. KI16 inhibited cell viability preferentially in STAT3-dependent cell lines. Taken together, using a targeted, cell-based approach, novel inhibitors of STAT-driven transcriptional activity were discovered which are interesting leads to pursue further for the development of anti-cancer therapeutic agents
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