Experimental study of high strength concrete-filled circular tubular columns under eccentric loading

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 paper is to establish the advisability of the use of high strength concretes as opposed to that of normal strength concretes by comparing three performance indices: concrete contribution ratio, strength index and ductility index. The results show for the limited cases analyzed that the use of high strength concrete for slender composite columns is interesting since this achieves ductile behavior despite the increase in load-carrying capacity is not greatly enhanced. © 2010 Elsevier Ltd. All rights reserved.The authors wish to express their sincere gratitude to the Spanish Ministry of Education for help provided through project BIA2005_255 and BIA 2009_09411, to the European Community for FEDER funds, and to the Fundacio Caixa Castello-Bancaixa.Portoles, J.; Romero, ML.; Bonet Senach, JL.; Filippou, F. (2011). Experimental study of high strength concrete-filled circular tubular columns under eccentric loading. Journal of Constructional Steel Research. 67(4):623-633. https://doi.org/10.1016/j.jcsr.2010.11.017S62363367

Derivation and external validation of the SIMPLICITY score as a simple immune-based risk score to predict infection in kidney transplant recipients

Existing approaches for infection risk stratification in kidney transplant recipients are suboptimal. Here, we aimed to develop and validate a weighted score integrating non-pathogen-specific immune parameters and clinical variables to predict the occurrence of post-transplant infectious complications. To this end, we retrospectively analyzed a single-center derivation cohort of 410 patients undergoing kidney transplantation in 2008-2013 in Madrid. Peripheral blood lymphocyte subpopulations, serum immunoglobulin and complement levels were measured at one-month post-transplant. The primary and secondary outcomes were overall and bacterial infection through month six. A point score was derived from a logistic regression model and prospectively applied on a validation cohort of 522 patients undergoing kidney transplantation at 16 centers throughout Spain in 2014-2015. The SIMPLICITY score consisted of the following variables measured at month one after transplantation: C3 level, CD4+ T-cell count, CD8+ T-cell count, IgG level, glomerular filtration rate, recipient age, and infection within the first month. The discrimination capacity in the derivation and validation cohorts was good for overall (areas under the receiver operating curve of 0.774 and 0.730) and bacterial infection (0.767 and 0.734, respectively). The cumulative incidence of overall infection significantly increased across risk categories in the derivation (low-risk 13.7%; intermediate-risk, 35.9%; high-risk 77.6%) and validation datasets (10.2%, 28.9% and 50.4%, respectively). Thus, the SIMPLICITY score, based on easily available immune parameters, allows for stratification of kidney transplant recipients at month one according to their expected risk of subsequent infection

Slender double-tube ultra-high strength concrete-filled tubular columns under ambient temperature and fire

This paper presents the results of an experimental campaign where both the room temperature and the fire resistance of six double-tube concrete filled steel tubular slender columns with different combinations of concrete strength are studied. Firstly, the ultimate axial load of the specimens at room temperatura was experimentally obtained and afterwards the fire resistance of such columns subjected to a 20% of their load bearing capacity was measured. Given the reduced number of experimental results found in the literature on slender concrete filled tubular columns with double steel tubular cross-sections, the main objective of this paper is to compare the behaviour of such innovative cross-sections under ambient and high temperatures. The influence of filling the inner ring with concrete on the fire performance of these columns is studied in this paper, as well as the variation of thicknesses of the outer and inner steel tubes. Despite the fact that the tested columns are not covered by the scope of Eurocode 4, the current simple calculation models were applied in this paper in order to assess the validity of the standard to this typology of columns, unsafe results being found.The authors would like to express their sincere gratitude to the Spanish Ministry of Economy and Competitivity through the project BIA2012-33144 and to the European Community for the FEDER funds.Romero, ML.; Espinós Capilla, A.; Portoles Flaj, JM.; Hospitaler Pérez, A.; Ibáñez Usach, C. (2015). Slender double-tube ultra-high strength concrete-filled tubular columns under ambient temperature and fire. Engineering Structures. 99:536-545. https://doi.org/10.1016/j.engstruct.2015.05.026S5365459

Effects of mesoporous SiO2-CaO nanospheres on the murine peritoneal macrophages/Candida albicans interface

The use of nanoparticles for intracellular drug delivery could reduce the toxicity and side effects of the drug but, the uptake of these nanocarriers could induce adverse effects on cells and tissues after their incorporation. Macrophages play a central role in host defense and are responsible for in vivo nanoparticle trafficking. Assessment of their defense capacity against pathogenic micro-organisms after nanoparticle uptake, is necessary to prevent infections associated with nanoparticle therapies. In this study, the effects of hollow mesoporous SiO2-CaO nanospheres labeled with fluorescein isothiocyanate (FITC-NanoMBGs) on the function of peritoneal macrophages was assessed by measuring their ability to phagocytize Candida albicans expressing a red fluorescent protein. Two macrophage/fungus ratios (MOI 1 and MOI 5) were used and two experimental strategies were carried out: a) pretreatment of macrophages with FITC-NanoMBGs and subsequent fungal infection; b) competition assays after simultaneous addition of fungus and nanospheres. Macrophage pro-inflammatory phenotype markers(CD80 expression and interleukin 6 secretion) were also evaluated. Significant decreases of CD80+ macrophage percentage and interleukin 6 secretion were observed after 30 min, indicating that the simultaneous incorporation of NanoMBG and fungus favors the macrophage non-inflammatory phenotype. The present study evidences that the uptake of these nanospheres in all the studied conditions does not alter the macrophage function. Moreover, intracellular FITC-NanoMBGs induce a transitory increase of the fungal phagocytosis by macrophages at MOI 1 and after a short time of interaction. In the competition assays, as the intracellular fungus quantity increased, the intracellular FITC-NanoMBG content decreased in a MOI- and time-dependent manner. These results have confirmed that macrophages clearly distinguish between inert material and the live yeast in a dynamic intracellular incorporation. Furthermore, macrophage phagocytosis is a critical determinant to know their functional state and a valuable parameter to study the nanomaterial / macrophages / Candida albicans interface

In vitro evaluation of graphene oxide nanosheets on immune function

Graphene oxide (GO) has attracted the scientific community attention due to its novel properties and wide range of potential applications including hyperthermia cancer therapy. However, little is known about the GO effects on the immune function which involves both innate and adaptive defence mechanisms through the activation of different cell populations and secretion of several cytokines. The effect of different GO nanosheets designed for hyperthermia cancer therapy on macrophage and lymphocyte function should be determined before using GO for this application. Experiments The effects of GO nanosheets with 1 (1-GOs) and 6 arms (6-GOs) of polyethylene glycol on RAW-264.7 macrophages and primary splenocytes (as approximation to the in vivo situation) were evaluated through the proinflammatory cytokine secretion and the modulation of cell proliferation in the presence of specific stimuli for either T-lymphocytes (concanavalin A, anti-CD3 antibody) or B-lymphocytes/macrophages (lipopolysaccharide). Findings 6-GOs significantly increased the secretion of TNF-α by RAW-264.7 macrophages without alteration of IL-6 and IL-1β levels. The treatment of primary splenocytes with 1-GOs and 6-GOs in the presence of concanavalin A, anti-CD3 antibody and lipopolysaccharide, produced significant dose-dependent decreases of cell proliferation and IL-6 levels, revealing weak inflammatory properties of GOs which are favourable for hyperthermia cancer therapy

An immunological approach to the biocompatibility of mesoporous SiO2-CaO nanospheres.

Mesoporous bioactive glass nanospheres (NanoMBGs) have high potential for clinicalapplications. However, the impact of nanoparticles on the immune system needs to be addressed. In this study, the biocompatibility of SiO2-CaO NanoMBGs was evaluated on different mouse immune cells, including spleen cells subsets, bone marrow-derived dendritic cells (BMDCs), or cell lines likevSR.D10 Th2 CD4+ lymphocytes and DC2.4 dendritic cells. Flow cytometry and confocal microscopy show that the nanoparticles were rapidly and efficiently taken up in vitro by T and B lymphocytes or by specialized antigen-presenting cells (APCs) like dendritic cells (DCs). Nanoparticles were not cytotoxic and had no effect on cell viability or proliferation under T-cell (anti-CD3) or B cell (LPS) stimuli. Besides, NanoMBGs did not affect the balance of spleen cell subsets, or the production of intracellular or secreted pro- and anti-inflammatory cytokines (TNF-α, IFN-γ, IL-2, IL-6, IL-10) by activated T, B, and dendritic cells (DC), as determined by flow cytometry and ELISA. T cell activation surface markers (CD25, CD69 and Induced Costimulator, ICOS) were not altered by NanoMBGs. Maturation of BMDCs or DC2.4 cells in vitro was not altered by NanoMBGs, as shown by expression of Major Histocompatibility Complex (MHC) and costimulatory molecules (CD40, CD80, CD86), or IL-6 secretion. The effect of wortmannin and chlorpromazine indicate a role for phosphoinositide 3-kinase (PI3K), actin and clathrin-dependent pathways in NanoMBG internalization. We thus demonstrate that these NanoMBGs are both non-toxic and non-inflammagenic for murine lymphoid cells and myeloid DCs despite their efficient intake by the cells

Effects of nanocrystalline hydroxyapatites on macrophage polarization

Silicon substituted and nanocrystalline hydroxyapatites have attracted the attention of many researchers due to their up-regulation in osteoblast cell metabolism and enhanced bioreactivity, respectively. On the other hand, the biomaterial success or failure depends ultimately on the immune response triggered after its implantation. Macrophages are the main components of the innate immune system with an important role in healing and tissue remodelling due to their remarkable functional plasticity, existing in a whole spectrum of functional populations with varying phenotypic features. The effects of nanocrystalline hydroxyapatite (nano-HA) and nanocrystalline silicon substituted hydroxyapatite (nano-SiHA) on the macrophage populations defined as pro-inflammatory (M1) and reparative (M2) phenotypes have been evaluated in the present study using RAW 264.7 cells and mouse peritoneal macrophages as in vitro models. M1 and M2 macrophage phenotypes were characterized by flow cytometry and confocal microscopy by the expression of CD80 and CD163, known as M1 and M2 markers, respectively. The polarization of primary macrophages towards the M1 or M2 phenotype was induced with the pro-inflammatory stimulus LPS or the anti-inflammatory stimulus IL-10, respectively, evaluating the biomaterial effects under these conditions. Our results show that both nano-HA and nano-SiHA favour the macrophage polarization towards an M2 reparative phenotype, decreasing M1 population and ensuring an appropriate response in the implantation site of these biomaterials designed for bone repair and bone tissue engineering

Dietary α‐Linolenic Acid, Marine ω‐3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta MEDiterránea (PREDIMED) Study

Background: Epidemiological evidence suggests a cardioprotective role of α‐linolenic acid (ALA), a plant‐derived ω‐3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine ω‐3 fatty acids (long‐chain n‐3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to all‐cause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for long‐chain n‐3 polyunsaturated fatty acids (≥500 mg/day). Methods and Results: We longitudinally evaluated 7202 participants in the PREvención con DIeta MEDiterránea (PREDIMED) trial. Multivariable‐adjusted Cox regression models were fitted to estimate hazard ratios. ALA intake correlated to walnut consumption (r=0.94). During a 5.9‐y follow‐up, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios for meeting ALA recommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56–0.92) for all‐cause mortality and 0.95 (95% CI 0.58–1.57) for fatal cardiovascular disease. The hazard ratios for meeting the recommendation for long‐chain n‐3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67–1.05) for all‐cause mortality, 0.61 (95% CI 0.39–0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29–0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22–1.01) for sudden cardiac death. The highest reduction in all‐cause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45–0.87]). Conclusions: In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to all‐cause mortality, whereas protection from cardiac mortality is limited to fish‐derived long‐chain n‐3 polyunsaturated fatty acids. Clinical Trial Registration URL: http://www.Controlled-trials.com/. Unique identifier: ISRCTN35739639

Differential clinical characteristics and prognosis of intraventricular conduction defects in patients with chronic heart failure

Intraventricular conduction defects (IVCDs) can impair prognosis of heart failure (HF), but their specific impact is not well established. This study aimed to analyse the clinical profile and outcomes of HF patients with LBBB, right bundle branch block (RBBB), left anterior fascicular block (LAFB), and no IVCDs. Clinical variables and outcomes after a median follow-up of 21 months were analysed in 1762 patients with chronic HF and LBBB (n = 532), RBBB (n = 134), LAFB (n = 154), and no IVCDs (n = 942). LBBB was associated with more marked LV dilation, depressed LVEF, and mitral valve regurgitation. Patients with RBBB presented overt signs of congestive HF and depressed right ventricular motion. The LAFB group presented intermediate clinical characteristics, and patients with no IVCDs were more often women with less enlarged left ventricles and less depressed LVEF. Death occurred in 332 patients (interannual mortality = 10.8%): cardiovascular in 257, extravascular in 61, and of unknown origin in 14 patients. Cardiac death occurred in 230 (pump failure in 171 and sudden death in 59). An adjusted Cox model showed higher risk of cardiac death and pump failure death in the LBBB and RBBB than in the LAFB and the no IVCD groups. LBBB and RBBB are associated with different clinical profiles and both are independent predictors of increased risk of cardiac death in patients with HF. A more favourable prognosis was observed in patients with LAFB and in those free of IVCDs. Further research in HF patients with RBBB is warranted

Differential effects of graphene oxide nanosheets on Candida albicans phagocytosis by murine peritoneal macrophages

Macrophages, as effector cells involved in the innate and adaptive immunity, play a key role in the response to nanomaterials as graphene oxide (GO) and in their cellular uptake. The interactions at the interface of GO nanosheets, macrophages and microbial pathogens need to be assessed to determine the possible impairment of the immune system induced by biomedical treatments with this nanomate-rial. Here, we have evaluated by flow cytometry and confocal microscopy the ability of murine peritoneal macrophages to phagocytose the fungal pathogen Candida albicans, alive or heat-killed, after treatment with poly(ethylene glycol-amine)-derivatized GO nanosheets (PEG-GO). After GO treatment, differences in fungal phagocytosis were observed between macrophages that had taken up GO nanosheets (GO+ pop-ulation) and those that had not (GO population). GO treatment increased the ingested alive yeasts in GO macrophages, whereas phagocytosis diminished in the GO+ population. Ingestion of heat-killed yeasts was slightly higher in both GO and GO+ populations when comparing with control macrophages. For the first time, we show that GO uptake by macrophages modulates its phagocytic capability, affecting differentially the subsequent ingestion of either alive or heat-killed yeasts. Enhanced ingestion of heat-killed yeast by GO-treated macrophages suggests a beneficial role of this nanomaterial for the clearance of dead microorganisms during infection.Ministerio de Economía y Competitividad(España)Fundação para a Ciência e a Tecnologia(Portugal)Depto. de Química en Ciencias FarmacéuticasFac. de FarmaciaTRUEpu