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The first objective of this experimental study is the assessment of the alkali activation potential of two types of fayalitic slags, an as-received one (FS) and the one obtained after plasma treatment (FSP) of the initial FS, for the production of alkali activated materials (AAMs). Furthermore, the second objective is the elucidation of the co-valorization potential of FS and FSP slags when mixed with ferronickel (FeNi) slag (LS). The alkaline activating solution used was a mixture of sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ). The effect of various operating parameters, such as H 2 O/Na 2 O and SiO 2 /Na 2 O ratios present in the activating solution, curing temperature, curing period and ageing period on the compressive strength, density, water adsorption, porosity and toxicity of the produced AAMs was explored. The structural integrity of selected AAMs was investigated after firing specimens for 6 h at temperature up to 500 °C, immersion in distilled water and acidic solution or subjection to freeze-thaw cycles for a period of 7 or 30 days. The results of this study show that FS- and FSP-based AAMs acquire compressive strength of 44.8 MPa and 27.2 MPa, respectively. When FS and FSP were mixed with LS at 50:50%wt ratios the compressive strength of the produced specimens increased to 64.3 MPa and 45.8 MPa, respectively. Furthermore, selected AAMs produced after co-valorisation of slags retained sufficient compressive strength after firing at 500 °C, 45-68 MPa, and exhibited very low toxicity. These findings prove the alkali activation potential of fayalitic slags as well as their co-valorization with ferronickel slag for the production of AAMs, an approach which is in line with the principles of zero-waste and circular economy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Socio-economic data on nickel and cobalt show their importance throughout the entire metal value chain, from mining to end use, disposal and recycling. Thus, the extraction of both metals from primary and secondary raw materials as well as from wastes is currently considered strategically important for the industry and the society. In this paper heap leaching of Greek low-grade saprolitic laterites, with Ni content 0.97%, was investigated. The main parameters studied involved the strength of the H 2 SO 4 solution used (49 and 147gL -1 ) and the effect of adding sodium sulfite (Na 2 SO 3 ) in the leaching medium. The pregnant leach solution (PLS) was recycled several times during leaching in order to minimize acid consumption. The experimental results showed that within a period of 25days, and under the optimum conditions (147gL -1 H 2 SO 4 and 20gL -1 Na 2 SO 3 ), i) Ni and Co extractions were 72.5% and 47.4%, respectively and ii) Fe and Al co-extractions were 8.7% and 31.3%, respectively. Furthermore, valorization of the leaching residues through alkali activation using NaOH and Na 2 SiO 3 and the addition of metakaolin (MK) for the production of inorganic polymers (IPs) was explored. X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Differential scanning calorimetry (DSC/TG) and Scanning electron microscopy (SEM-EDS) were used to characterize the ore, its leaching residues and the IPs. The IPs produced demonstrated high compressive strength, almost 40MPa and are suitable for a wide range of applications in the construction sector., (Copyright © 2018. Published by Elsevier B.V.)

Objectives: Toll-like Receptor 4 (TLR4) is implicated in modulating inflammatory cytokines though its role in atherosclerosis remains uncertain. We have recently described a non-foam cell macrophage phenotype driven by ingestion of hemoglobin:haptoglobin complexes (HH), via the scavenger receptor CD163, characterized by reduced inflammatory cytokine production. In this study, we examined the role of iron metabolism in modulating TLR4 signaling in these cells., Methods and Results: Areas in human atherosclerotic plaque with non-foam cell, CD163 positive macrophages demonstrated reduced expression of tumor necrosis factor alpha (TNF-α) and interferon-beta (INF-β) compared to foam cells. Human macrophages differentiated in hemoglobin:haptoglobin (HH) complexes expressed the CD163 positive non-foam cell phenotype and demonstrated significantly less TNF-α and INF-β compared to control macrophages when exposed to oxidized LDL (oxLDL) or lipopolysaccharide (LPS). LPS stimulated expression of TNF-α and INF-β could be restored in HH macrophages by pretreatment with hepcidin, an endogenous suppressor of ferroportin1 (FPN), or by genetic suppression of FPN in macrophages derived from myeloid specific FPN knockout mice. LPS stimulated control macrophages demonstrated increase in TLR4 trafficking to lipid rafts; this response was suppressed in HH macrophages but was restored upon pretreatment with hepcidin. Using a pharmacologic hepcidin suppressor, we observed a decrease in cytokine expression and TLR4-lipid raft trafficking in LPS-stimulated in a murine macrophage model., Conclusion: TLR4 dependent macrophage signaling is controlled via hepcidin-ferroportin1 axis by influencing TLR4-lipid raft interactions. Pharmacologic manipulation of iron metabolism may represent a promising approach to limiting TLR4-mediated inflammatory responses., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objectives: Metformin impairs endothelialization of drug eluting stents (DES) due to convergent signaling at the mammalian target of rapamycin (mTOR) pathway. We assessed whether metformin will continue to adversely affect stent endothelialization despite design improvements in newer generation DES., Methods: Rabbit iliac artery stenting with newer generation DES was performed followed by 14 days of either normal chow diet or one with metformin (100 mg/kg/day) added. Scanning electron microscopy was used to assess stent endothelialization after sacrifice., Results: In the metformin-treated group there was significantly less endothelialization compared to the placebo-treated group. Paclitaxel-eluting stents in placebo-treated group had the greatest degree of endothelialization with significantly less in its metformin-treated counterpart and all-limus eluting stent groups., Conclusions: Metformin inhibited stent endothelialization in newer generation DES despite improvements in stent design. By impairing stent endothelialization, metformin may increase the risk for thrombotic complications after newer generation DES placement., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)