Empleo de materiales secundarios como materia prima de nuevos tipos de cementos

The present paper is a comparative study of some characteristics of new belite cements obtained from two kind of wastes, which were used as secondary raw materials: fly ash (FA), of low CaO content, from coal combustion, and ash from incineration of municipal solid waste (MSWIA). Cements were synthesised in a range of temperature between 700°C and 900°C from MSWIA and FA, which were previously activated by hydrothermal treatment at 200°C The evolution of cemented phases with the heating temperature was followed by X-ray diffraction (XRD). The results were compared with those obtained from heating the starting FA and MSWIA without the previous hydrothermal treatment. The degree of hydration was quantitatively evaluated by the combined water content, determined from thermogravimetric analyses, during a period of 28 days or 200 days from mixing depending of hydration kinetics of each cement.Este trabajo es un estudio comparativo de algunas de las características de nuevos cementos belíticos, obtenidos a partir de dos tipos de residuos, como materia prima secundaria: cenizas volantes (CV) de bajo contenido en cal, procedentes de la combustión del carbón y cenizas procedentes de la incineración de residuos sólidos urbanos (CIRSU). Los cementos fueron sintetizados en un rango de temperaturas comprendido entre 700°C y 900°C después de un tratamiento hidrotermal de la CV y CIRSU a 200°C La evolución de las fases cementicias, con la temperatura de calentamiento, fue estudiada por difracción de rayos X (DRX). Los resultados fueron comparados con aquellos obtenidos, directamente, por calentamiento de los residuos, sin un tratamiento hidrotermal previo de los mismos. El grado de hidratación fue cuantitativamente evaluado, por medio del análisis termogravimétrico, a partir del agua combinada de los cementos hidratados durante un período de 28 días o 200 días, dependiendo de la cinética de hidratación de cada cemento

Precision of Digital Volume Correlation Approaches for Strain Analysis in Bone Imaged with Micro-Computed Tomography at Different Dimensional Levels

Accurate measurement of local strain in heterogeneous and anisotropic bone tissue is fundamental to understand the pathophysiology of musculoskeletal diseases, to evaluate the effect of interventions from preclinical studies, and to optimize the design and delivery of biomaterials. Digital volume correlation (DVC) can be used to measure the three-dimensional displacement and strain fields from micro-computed tomography (μCT) images of loaded specimens. However, this approach is affected by the quality of the input images, by the morphology and density of the tissue under investigation, by the correlation scheme, and by the operational parameters used in the computation. Therefore, for each application, the precision of the method should be evaluated. In this paper, we present the results collected from datasets analyzed in previous studies as well as new data from a recent experimental campaign for characterizing the relationship between the precision of two different DVC approaches and the spatial resolution of the outputs. Different bone structures scanned with laboratory source μCT or synchrotron light μCT (SRμCT) were processed in zero-strain tests to evaluate the precision of the DVC methods as a function of the subvolume size that ranged from 8 to 2,500 µm. The results confirmed that for every microstructure the precision of DVC improves for larger subvolume size, following power laws. However, for the first time, large differences in the precision of both local and global DVC approaches have been highlighted when SRμCT or in vivo μCT images were used instead of conventional ex vivo μCT. These findings suggest that in situ mechanical testing protocols applied in SRμCT facilities should be optimized to allow DVC analyses of localized strain measurements. Moreover, for in vivo μCT applications, DVC analyses should be performed only with relatively course spatial resolution for achieving a reasonable precision of the method. In conclusion, we have extensively shown that the precision of both tested DVC approaches is affected by different bone structures, different input image resolution, and different subvolume sizes. Before each specific application, DVC users should always apply a similar approach to find the best compromise between precision and spatial resolution of the measurements

Polyelectrolyte Multilayered Capsules as Biomedical Tools

Polyelectrolyte multilayered capsules (PEMUCs) obtained using the Layer-by-Layer (LbL) method have become powerful tools for different biomedical applications, which include drug delivery, theranosis or biosensing. However, the exploitation of PEMUCs in the biomedical field requires a deep understanding of the most fundamental bases underlying their assembly processes, and the control of their properties to fabricate novel materials with optimized ability for specific targeting and therapeutic capacity. This review presents an updated perspective on the multiple avenues opened for the application of PEMUCs to the biomedical field, aiming to highlight some of the most important advantages offered by the LbL method for the fabrication of platforms for their use in the detection and treatment of different diseases

Full-field strain analysis of bone-biomaterial systems produced by the implantation of osteoregenerative biomaterials in an ovine model

Osteoregenerative biomaterials for the treatment of bone defects are under much development, with the aim of favoring osteointegration up to complete bone regeneration. A detailed investigation of bone–biomaterial integration is vital to understand and predict the ability of such materials to promote bone formation, preventing further bone damage and supporting load-bearing regions. This study aims to characterize the ex vivo micromechanics and microdamage evolution of bone–biomaterial systems at the tissue level, combining high-resolution synchrotron microcomputed tomography, in situ mechanics and digital volume correlation. Results showed that the main microfailure events were localized close to or within the newly formed bone tissue, in proximity to the bone–biomaterial interface. The apparent nominal compressive load applied to the composite structures resulted in a complex loading scenario, mainly due to the higher heterogeneity but also to the different biomaterial degradation mechanisms. The full-field strain distribution allowed characterization of microdamage initiation and progression. The findings reported in this study provide a deeper insight into bone–biomaterial integration and micromechanics in relation to the osteoregeneration achieved in vivo for a variety of biomaterials. This could ultimately be used to improve bone tissue regeneration strategies

Frequency analysis of vocalisations in relation to the growth in broiler chicken

Poultry is one of the lowest cost sources of animal protein in the world and, more than 40 billion chickens are produced every year globally. For reasons of public concern and due to the large number of animals involved, it is considered by many people to be important to take care of the welfare and health status of the chickens reared under intensive farm conditions. Precision Livestock Farming (PLF) can support the farmer in his day to day routine management through the use of sensors, cameras and microphones, and these have the potential to improve production and to enable monitoring of welfare status. In this context, the 7FP EU-PLF project aims to test the efficiency of the use of those sensors at farm level. In particular, the aim of this study was to record and analyse broiler vocalisations under normal farm conditions and to identify the relation between animal sounds, and growth trends. Recordings were made at regular intervals, for the entire short production life of the birds, in order to evaluate the variation of frequency and bandwidth of the sounds emitted by the animals during the cycle of production. The recordings were made in an automated, non-invasive and non-intrusive way and the sound data was compared with the weight of the birds automatically measured by a 'step on scale' placed on the floor of the broiler house. Sound analysis was performed based on the amplitude and frequency of the sound signal in audio files recorded at farm level. Through analysis of the sounds recorded, a significant correlation (P<0.001) between the frequencies of the vocalisations recorded and the weight of the broilers was found across all production cycles and farms assessed. The ongoing goal will be the development of a tool able to automatically detect the growth of the animals based on the frequency of the vocalisation emitted by the birds at different ages, and as a possible tool for determining deviations from their expected growth trend

Real-time modelling of indoor particulate matter concentration in poultry houses using broiler activity and ventilation rate

Measuring particulate matter concentration in poultry houses remains as a difficult task, primarily because aerosol analysers are expensive, require specialist knowledge to operate and are labour intensive to maintain. However, it is well known that high concentrations of particulate matter causes health and welfare problems with livestock, farm workers and people living in the vicinity of the farm premises. In this work, a data-based mechanistic model is developed to relate broiler activity and ventilation rate with indoor particulate matter concentration. For six complete growing cycles, in a U.K. commercial poultry farm, broiler activity was monitored using a camera-based flock monitoring system (eYeNamic®) and ventilation rate was measured. Indoor particulate matter concentration was continuously monitored by measuring size-segregated mass fraction concentrations with the aerosol analyser DustTrakTM. A discrete-time multi-input single-output time-invariant parameters Transfer Function model was developed to determine the particulate dynamics within each day of the growing cycle in the poultry house using broiler activity and ventilation rate as inputs. This model monitored indoor particulate matter concentration with an average accuracy of RT2=(51±26)%. A dynamic linear regression modelling with time-variant parameters improved average accuracy with RT2=(97.7±1.3)%. It forecasted one sample-ahead the indoor particulate matter concentration level, using a time window of 14 samples, with a mean relative prediction error, MRPE=(4.6±3.2)%. Thus, dynamic modelling with time-variant parameters has the potential to be part of a control system to manage in real-time indoor particulate matter concentration in broiler houses.status: publishe

On studying the interaction between different stent models and rabbit tracheal tissue: numerical, endoscopic and histological comparison

Stenting technique is employed worldwide for treating atherosclerotic vessel and tracheal stenosis. Both diseases can be treated by means of metallic stents which present advantages but are affected by the main problem of restenosis of the stented area. In this study we have built a rabbit trachea numerical model and we have analyzed it before and after insertion and opening of two types of commercial stent: a Zilver® FlexTM Stent and a WallStentTM. In experimental parallel work, two types of stent were implanted in 30 New Zealand rabbits divided in two groups of 10 animals corresponding to each stent type and a third group made up of 10 animals without stent. The tracheal wall response was assessed by means of computerized tomography by endoscopy, macroscopic findings and histopathological study 90 days after stent deployment. Three idealized trachea models, one model for each group, were created in order to perform the computational study. The animal model was used to validate the numerical findings and to attempt to find qualitative correlations between numerical and experimental results. Experimental findings such as inflammation, granuloma and abnormal tissue growth, assessed from histomorphometric analyses were compared with derived numerical parameters such as wall shear stress (WSS) and maximum principal stress. The direct comparison of these parameters and the biological response supports the hypothesis that WSS and tensile stresses may lead to a greater tracheal epithelium response within the stented region, with the latter seeming to have the dominant role. This study may be helpful for improving stent design and demonstrates the feasibility offered by in-silico investigated tracheal structural and fluid dynamics

Parathyroid hormone-related protein as a renal regulating factor: From Vessels to Glomeruli and Tubular Epithelium

Parathyroid hormone (PTH) and PTH-related protein (PTHrP) produce similar biological effects through the PTH/PTHrP receptor. Less is known about the physiological role of PTHrP, which was first identified as the agent of the humoral hypercalcemia of malignancy. Despite the widespread production of PTHrP in healthy individuals, the concentration of the protein is below the detectable limit of current assays, suggesting that PTHrP normally functions locally in an autocrine or paracrine manner. Thus, some differences in their biological activities have been described and they may be related to the presence of different receptors. In this regard, a second receptor that binds selectively to PTH has also been found. Recent studies have demonstrated the expression of both PTH/PTHrP receptor and protein in the renal glomeruli. Moreover, there are convincing data that support a direct role of PTH and PTHrP in modulating renal blood flow and glomerular filtration rate. This multifunctional protein, PSHrP, also has a proliferative effect on both glomerular mesangial cells and tubular epithelial cells. Increases in the expression of PTHrP have been observed in several experimental models of nephropathies, suggesting that PTHrP upregulation is a common event associated with the mechanism of renal injury and repair

LmjF.22.0810 from Leishmania major Modulates the Th2-Type Immune Response and Is Involved in Leishmaniasis Outcome

A novel serine/threonine protein kinase, LmjF.22.0810, was recently described in Leishmania major. After generating an L. major cell line overexpressing LmjF.22.0810 (named LmJ3OE), the ability of this novel protein to modulate the Th2-type immune response was analyzed. Our results suggest that the protein kinase LmjF.22.0810 might be involved in leishmaniasis outcomes. Indeed, our study outlined the LmJ3OE parasites infectivity in vitro and in vivo. Transgenic parasites displayed lower phagocytosis rates in vitro, and their promastigote forms exhibited lower expression levels of virulence factors compared to their counterparts in control parasites. In addition, LmJ3OE parasites developed significantly smaller footpad swelling in susceptible BALB/c mice. Hematoxylin–eosin staining allowed the observation of a lower inflammatory infiltrate in the footpad from LmJ3OE-infected mice compared to animals inoculated with control parasites. Gene expression of Th2-associated cytokines and effectors revealed a dramatically lower induction in interleukin (IL)-4, IL-10, and arginase 1 (ARG1) mRNA levels at the beginning of the swelling; no expression change was found in Th1-associated cytokines except forIL-12. Accordingly, such results were validated by immunohistochemistry studies, illustrating a weaker expression of ARG1 and a similar induction for inducible NO synthase (iNOS) in footpads from LmJ3OE-infected mice compared to control L. major infected animals. Furthermore, the parasite burden was lower in footpads from LmJ3OE-infected mice. Our analysis indicated that such significant smaller footpad swellings might be due to an impairment of the Th2 immune response that subsequently benefits Th1 prevalence. Altogether, these studies depict LmjF.22.0810 as a potential modulator of host immune responses to Leishmania. Finally, this promising target might be involved in the modulation of infection outcome