1,081 research outputs found
Analysis of tensile behavior of recycled aggregate concrete using acoustic emission technique
Recycled concrete aggregate (RCA) was processed from reinforced concrete edge beams sourced from a demolished bridge in Sweden. This material replaced different ratios of coarse aggregate in a benchmark concrete. The tensile behavior of the developed concrete mixes was characterized via monotonic and cyclic uniaxial tensile tests performed on notched cylinders. Such tensile tests allow for the quantification of the fracture energy and softening behavior of the concrete. Moreover, acoustic emission (AE) measurements were conducted in conjunction with the cyclic tests to characterize e.g. micro‐crack initiation and development, as well as crack localization. The tensile behavior of the various materials was found to be similar with minimal variation in the results. However, the softening behavior suggests that the RCA materials are slightly more brittle compared to both the mother and benchmark materials, which could be indicative of differences in the interface transition zones. The corresponding AE measurements also indicated similarities between the micro‐crack initiation and development for these mixes. It can be constituted that if the concrete used to produce RCA is of high quality and from one source, the resulting RAC will have adequate tensile properties with minimal variation, despite the aggregate replacement ratio
Mouse Mesenchymal Progenitor Cells Expressing Adipogenic and Osteogenic Transcription Factors Suppress the Macrophage Inflammatory Response
Mesenchymal progenitor cell characteristics that can identify progenitor populations with specific functions in immunity are actively being investigated. Progenitors from bone marrow and adipose tissue regulate the macrophage (MΦ) inflammatory response by promoting the switch froman inflammatory to an anti-inflammatory phenotype.Conversely,mesenchymal progenitors fromthe mouse aorta (mAo) support and contribute to the MΦ response under inflammatory conditions.We used cell lines with purported opposing immune-regulatory function, a bonemarrow derivedmesenchymal progenitor cell line (D1) and amouse aorta derived mesenchymal progenitor cell line (mAo). Their interaction and regulation of the MΦ cell response to the inflammatory mediator, lipopolysaccharide (LPS), was examined by coculture. As expected, D1 cells suppressed NO, TNF-, and IL-12p70 production but MΦ phagocytic activity remained unchanged. The mAo cells enhanced NO and TNF- production in coculture and enhanced MΦ phagocytic activity. Using flow cytometry and PCR array, we then sought to identify sets of MSC-associated genes and markers that are expressed by these progenitor populations.We have determined that immune-supportive mesenchymal progenitors highly express chondrogenic and tenogenic transcription factors while immunosuppressive mesenchymal progenitors highly express adipogenic and osteogenic transcription factors. These data will be useful for the isolation, purification, and modification of mesenchymal progenitors to be used in the treatment of inflammatory diseases
A Quest for a Custom-Made Mesenchymal Stem Cell in the Treatment of Inflammatory Diseases
Mesenchymal stem cells (MSC) are multipotent cells that can differentiate into adipocytes, osteoblasts and chondrocytes. These cells are widely studied in tissue regeneration and for their therapeutic effects in inflammatory disease. MSC interact with cells of the innate and adaptive immunity to promote or suppress the inflammatory response. MSC from the bone marrow (D1 MSC) decrease inflammatory responses by lowering macrophage (Mᶲ) secretion of soluble factors such as nitric oxide (NO), interleukin-12 (IL-12) and tumor necrosis factor-α (TNFα). Aorta-derived MSC (mAo MSC) support the macrophage inflammatory response by contributing to NO secretion and enhancing secretion of TNFα by Mᶲ. Previous studies have isolated and enriched MSC populations using one or two specific cell surface markers and subsequently tested their functional properties in the regulation of immune cells. In this study we took a different approach. Using two populations of MSC with opposing immune regulatory function, we examined differences in their MSC-associated gene expression using PCR array. We sought to identify sets of MSC-associated genes that correlate with either suppression or support of the Mᶲ inflammatory response. Our results revealed that the mAo MSC express genes that potentiate chondrogenic differentiation, while the D1 MSC express genes that potentiate adipogenic and osteogenic differentiation. Our unique approach identified MSC populations that have greater propensity to develop into osteogenic and adipogenic lineages are immunosuppressive, while those with greater propensity to develop into chondrocytes are immuno-supportive. We have identified lineage potential as a way to select MSC populations for use in cell-based therapies of inflammatory disease
Propuesta de mejora en las áreas de producción y logística para reducir los costos operacionales de un molino en la ciudad de Trujillo
El presente trabajo tiene como objetivo diagnosticar los costos operacionales en las áreas de producción y logística para diseñar una propuesta de mejora e incrementar su rentabilidad. Se inició con un diagnóstico y análisis de la situación actual de dichas áreas, obteniendo como resultado que en ambas se generan pérdidas mensuales de S/6098.95. Asimismo, se identificaron y desarrollaron herramientas de mejora para cada uno de los problemas con mayor valorización por los trabajadores del molino relacionados con la gestión de producción y logística: un Plan de Mantenimiento Preventivo, un Procedimiento Estándar y MRP, un formato Kárdex, la Metodología 5S y ABC. Por último, se realizó una evaluación económica financiera para la factibilidad y rentabilidad de la propuesta y se obtuvo el beneficio por un valor de S/. 2002.49, un VAN de S/14150, TIR de 26% y B/C de 2.85, con un periodo de recuperación de la inversión de 12 meses, por lo que se demostró que la propuesta es viable
Restraining of glycoprotein VI- and integrin α2β1-dependent thrombus formation y platelet PECAM1
The platelet receptors, glycoprotein VI (GPVI) and integrin α2β1 jointly control collagen-dependent thrombus formation via protein tyrosine kinases. It is unresolved to which extent the ITIM (immunoreceptor tyrosine-based inhibitory motif) receptor PECAM1 and its downstream acting protein tyrosine phosphatase PTPN11 interfere in this process. Here, we hypothesized that integrin α2β1 has a co-regulatory role in the PECAM1- and PTPN11-dependent restraint of thrombus formation. We investigated platelet activation under flow on collagens with a different GPVI dependency and using integrin α2β1 blockage. Blood was obtained from healthy subjects and from patients with Noonan syndrome with a gain-of-function mutation of PTPN11 and variable bleeding phenotype. On collagens with decreasing GPVI activity (types I, III, IV), the surface-dependent inhibition of PECAM1 did not alter thrombus parameters using control blood. Blockage of α2β1 generally reduced thrombus parameters, most effectively on collagen IV. Strikingly, simultaneous inhibition of PECAM1 and α2β1 led to a restoration of thrombus formation, indicating that the suppressing signaling effect of PECAM1 is masked by the platelet-adhesive receptor α2β1. Blood from 4 out of 6 Noonan patients showed subnormal thrombus formation on collagen IV. In these patients, effects of α2β1 blockage were counterbalanced by PECAM1 inhibition to a normal phenotype. In summary, we conclude that the suppression of GPVI-dependent thrombus formation by either PECAM1 or a gain-of-function of PTPN11 can be overruled by α2β1 engagement
Análisis de la reparación administrativa en Colombia a la luz de la jurisprudencia de la Corte Interamericana de Derechos Humanos.
This article is part of a research project, which aims to analyze whether the Administrative reparation in Colombia is consistent with the Inter-American Court on Human Rights standards of reparation. This article identifies the integral reparation standards in light of the jurisprudence of that court. It states the administrative reparation concept and its extent in Colombia, and it finally presents an analysis of compliance with the standards in the reparation granted to 50 victims of the armed conflict, who were assisted in the Consultorio Jurídico de Desplazamiento Forzado de la Universidad de Cartagena.El presente artículo hace parte del proyecto titulado de la misma manera,4 el cual tiene por objeto analizar si la reparación administrativa en Colombia se encuentra conforme con los estándares de reparación de la Corte Interamericana de Derechos Humanos (CIDH). Específicamente, se identifican los estándares de reparación integral a la luz de la jurisprudencia de la citada Corte, se determina el concepto y alcance de la reparación administrativa en Colombia y finalmente se concreta el cumplimiento de los estándares en la reparación otorgada a 50 víctimas del conflicto armado, que fueron asistidas en el Consultorio Jurídico de Derecho y Desplazamiento de la Universidad de Cartagena
Parallel soiling measurements for 4 mirror samples during outdoor exposure with TraCS
The upgraded version of the Tracking Cleanliness Sensor, the so-called TraCS4, which determines the realtime cleanliness and soiling rate of four mirror samples simultaneously is presented. Using this device, different materials can be intercompared at the site of interest which is the main advantage as the performance of anti-soiling-coatings is usually dependent on local weather conditions. A detailed uncertainty analysis of the TraCS4 device results in a cleanliness measurement uncertainty of about 0.019 cleanliness points. The uncertainty for the intercomparison of different materials is derived to be 0.012 cleanliness points. Exemplary soiling measurements with different anti-soiling and reference coatings at PSA are presented
Energija i pravednost
The airborne transmission of infection relies on the ability of pathogens to
survive aerosol transport as they transit between hosts. Understanding the
parameters that determine the survival of airborne microorganisms is critical
to mitigating the impact of disease outbreaks. Conventional techniques for
investigating bioaerosol longevity in vitro have systemic limitations that prevent the accurate representation of conditions that these particles would
experience in the natural environment. Here, we report a new approach
that enables the robust study of bioaerosol survival as a function of relevant
environmental conditions. The methodology uses droplet-on-demand technology for the generation of bioaerosol droplets (1 to greater than 100 per
trial) with tailored chemical and biological composition. These arrays of droplets are captured in an electrodynamic trap and levitated within a
controlled environmental chamber. Droplets are then deposited on a substrate after a desired levitation period (less than 5 s to greater than 24 h).
The response of bacteria to aerosolization can subsequently be determined
by counting colony forming units, 24 h after deposition. In a first study, droplets formed from a suspension of Escherichia coli MRE162 cells (108 ml21
)
with initial radii of 27.8+0.08 mm were created and levitated for extended
periods of time at 30% relative humidity. The time-dependence of the survival rate was measured over a time period extending to 1 h. We demonstrate
that this approach can enable direct studies at the interface between aerobiology, atmospheric chemistry and aerosol physics to identify the factors that
may affect the survival of airborne pathogens with the aim of developing
infection control strategies for public health and biodefence applications
Evaluation of methods for the concentration and extraction of viruses from sewage in the context of metagenomic sequencing
Viral sewage metagenomics is a novel field of study used for surveillance, epidemiological studies, and evaluation of waste water treatment efficiency. In raw sewage human waste is mixed with household, industrial and drainage water, and virus particles are, therefore, only found in low concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different ways employing a wide range of viral concentration and extraction procedures. However, there is limited knowledge of the efficacy and inherent biases associated with these methods in respect to viral sewage metagenomics, hampering the development of this field. By the use of next generation sequencing this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit, NucliSENS® miniMAG®, or PowerViral® Environmental RNA/DNA Isolation Kit) to determine the viriome in a sewage sample. We found a significant influence of concentration and extraction protocols on the detected viriome. The viral richness was largest in samples extracted with QIAamp Viral RNA Mini Kit or PowerViral® Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method associated biases, within the field of viral sewage metagenomics, making evaluation of the current literature easier and helping with the design of future studies
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