Processing and characterisation of Calcium SulfoAluminate (CSA) eco-cements coated with a hybrid organo-inorganic material for photocatalytic applications

On the one hand, Calcium SulfoAluminate (CSA) eco-cements are receiving increasing attention since their manufacture produces up to 40% less CO2 than ordinary Portland cement (OPC). In addition, they show interesting properties such as high early-age strengths, short setting times, impermeability, sulfate and chloride corrosion resistance and low alkalinity. On the other hand, water treatment is a key issue and it will become much more important in the decades ahead. We have developed a photocatalytic material capable to degrade contaminants in water, under both UVA and visible radiations. In both cases, it works more effectively than nano-TiO2 (Evonik P25). The environmental benefits of the use of CSA eco-cements with a photocatalyst are two folds: the photocatalytic treatment of contaminated water, and lower CO2 emissions because of the use of eco-cements rather than OPC. However, before preparing the coating, different parameters need to be under control. This includes the effect of the photocatalyst onto the eco-cement (setting time, phase assemblage, and so on), and the effect of the eco-cement on the photocatalyst. This work deals with the processing and characterisation of coatings onto CSA eco-cement pastes, including rheological behaviour, setting time, adhesion, and so on.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been supported by Junta de Andalucía (Spain) through P11-FQM-7517 and P12-FQM-1656 research grants and FEDER/University of Málaga (FC14-MAT-23). Dr. I. Santacruz thanks a Ramón y Cajal fellowship, RYC-2008-03523

Detection and counting of Cryptosporidium parvum in HCT-8 cells by flowcytometry.

The objective of the present study was to evaluate flowcytometry analysis (FCA) as a tool for rapidly and objectively estimating the percentage of cells infected with Cryptosporidium parvum in an in vitro model. We compared the results to those obtained with immunofluorescence assay (IFA) and evaluated the intra-assay variability of both assays and the inter-assay variability of IFA. Human ileocecal adenocarcinoma cells (HCT-8) were infected with different doses of excysted oocysts. After 24 hours, cells were analysed by FCA and by IFA using a monoclonal antibody that recognises a C. parvum antigenic protein and a lectin that binds with glycoproteins present in the parasitophorous vacuoles. The coefficient of variability in terms of the percentage of infected cells was lower for FCA (i.e., 13-14 %) than for IFA (i.e., 27-38 % when performed by a single operator and 19-22 % when performed by three operators), suggesting that FCA is more accurate, in that it is not subject to operator expertise. FCA also has the advantage of allowing the entire culture to be examined, thus avoiding problems with heterogeneity among microscopic fields. In light of these results, this method could also be used to test new anti-Cryptosporidium drugs

Recent Advances in C-S-H Nucleation Seeding for Improving Cement Performances

Reducing cement CO2 footprint is a societal need. This is being achieved mainly by replacing an increasing amount of Portland clinker by supplementary cementitious materials. However, this comes at a price: lower mechanical strengths at early ages due to slow pozzolanic reaction(s). This is being addressed by using accelerator admixtures. In this context, calcium silicate hydrate nucleation seeding seems to have a promising future, as it can accelerate cement and pozzolanic reactions at early ages, optimising their microstructures, without compromising late strength and durability performances. In fact, these features could even be improved. Moreover, other uses are low temperature concreting, precasting, shotconcrete, etc. Here, we focus on reviewing recent reports on calcium silicate hydrate seeding using commercially available admixtures. Current knowledge on the consequences of nucleation seeding on hydration reactions and on early and late mechanical strengths is discussed. It is noted that other features, in addition to the classic alite hydration acceleration, are covered here including the enhanced ettringite precipitation and the very efficient porosity refinement, which take place in the seeded binders. Finally, because the seeded binders seem to be denser, durability properties could also be enhanced although this remains to be properly established.This research has been partly supported by PID2020-114650RB-I00 research grant, Spanish Government, which is co-funded by ERDF

In-situ synchrotron powder diffraction study: activation of Portland and Belite cements

Portland cement (PC), whose main phase is alite (Ca3SiO5, C3S), is one of the most manufactured products in the world. However, cement industry is one of the major contributors for greenhouse gases (GHG) emissions. In the fabrication of PC, 0.96 tons CO2 per ton PC are emitted into the atmosphere. Belite cements (BC), whose main component is the belite phase (Ca2SiO5, C2S), can decrease the CO2 footprint of cements. The main disadvantage of these BCs is its low mechanical strengths at early ages although they have very good mechanical values at late ages and also very good durability performances. Thus, it is necessary to study how to increase the mechanical properties at early ages, for instance, by activation. To do this, an in-situ synchrotron X-ray powder diffraction study has been performed up to 48 hours of hydration using a PC and two different BCs (one activated during the clinkering stage and one non-activated). These cements have been hydrated without and with three different admixtures, two of them C-S-H seeding based (XS100 and XS130) and the other one being a single alkanolamine (triisopropanolamine, TIPA). Data have been collected at the BL04-MSPD beamline at ALBA synchrotron (Barcelona, Spain). The results were analysed by the Rietveld methodology to determine the phase content evolutions with time and with the activators. Fig. 1 shows, as an example, the hydration evolution of the activated BC without and with the XS130 admixture. In this study, we have obtained two main conclusions. The first observation is that C-S-H seeding accelerates the hydration of the three cements at early ages, mainly by enhancing calcium sulphates and calcium aluminates dissolutions. It has also been observed that admixtures do not significantly accelerate the hydration of crystalline C3S and C2S. The second is a synergy between C-S-H seeding and alkanolamines when compare to single alkanolamine dosage.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Early hydration of belite-ye’elimite-ferrite cements: Role of admixtures

The effect of TIPA and CaCl2 on early hydration, i.e. 24 h, of a B-BYF cement has been studied by in situ synchrotron X-ray powder diffraction, calorimetry, thermal analysis, NMR, and rheological measurements of the pastes and mechanical strength of the corresponding mortars. The addition of 0.05 %bwc (by weight of cement) of TIPA reduced the viscosity of the paste during the first minutes of hydration but, after the end of the induction period, ~7 h, it favored the formation of AFt compared to the reference paste. The latter is likely due to the acceleration of the dissolution of the amorphous aluminates and sulfates by the presence of TIPA. These results correlate with the increase of ~169% of the 1-day mechanical strengths. The addition of 2.0 %bwc of CaCl2 accelerated the dissolution rate of ye’elimite, causing an increase of the amount of precipitated ettringite even before the end of the induction period, which has been shorted to ~6 h. The 1-day mechanical strengths of the mortars with this admixture outperforms that of the reference mortar by 181%. Finally, ferrite and α’ H-belite reactivities were not affected by the addition of any of these admixtures during the first 24 h of hydration of this cement.P18-RT-720 from the Andalusian regional government and PID2019-104378RJ-I00 from the Spanish government are gratefully acknowl-edged. ALBA synchrotron is acknowledged for providing with beamtime at MSPD beamline. Funding for open access charge: Universidad de Málaga / CBUA

Kinematic Effect on the Navicular Bone with the Use of Rearfoot Varus Wedge

: Background: The rearfoot varus wedge (RVW) is a common treatment for foot pain and valgus deformity. There is research on its effects in the calcaneus, but there is little research on the navicular. More research is needed with the use of RVW due to the relationship that exists between the position of the navicular and the risk of suffering an injury. Objectives: this study sought to understand how RVW can influence the kinematics of the navicular bone, measuring their movement with the 6 SpaceFastrak system. Methods: a total of 60 subjects participated in the study. Two sensors were used to measure the movement of the calcaneus and navicular using RVWs as compared in the barefoot position in a static way. Results: there were statistically significant differences, the use of RVWs caused changes in the navicular bone, with subjects reaching the maximum varus movement with the use of RVW 7 mm of 1.35 ± 2.41◦ (p < 0.001), the maximum plantar movement flexion with the use of RVW 10 mm of 3.93 ± 4.44◦ (p < 0.001). Conclusions: when RVWs were placed under the calcaneus bone, the navicular bone response was in varus movement too; thus, the use of rearfoot varus wedge can influence the movement of the navicular bone

Portland and belite cement hydration acceleration by C-S-H seeds with variable w/c ratios

The acceleration of very early age cement hydration by C-S-H seeding is getting attention from scholars and field applications because the enhanced early age features do not compromise later age performances. This acceleration could be beneficial for several low-CO2 cements as a general drawback is usually the low very early age mechanical strengths. However, the mechanistic understanding of this acceleration in commercial cements is not complete. Reported here is a contribution to this understanding from the study of the effects of C-S-H gel seeding in one Portland cement and two belite cements at two widely studied water–cement ratios, 0.50 and 0.40. Two commercially available C-S-H nano-seed-based admixtures, i.e., Master X-Seed 130 and Master X-Seed STE-53, were investigated. A multi-technique approach was adopted by employing calorimetry, thermal analysis, powder diffraction (data analysed by the Rietveld method), mercury intrusion porosimetry, and mechanical strength determination. For instance, the compressive strength at 1 day for the PC (w/c = 0.50) sample increased from 15 MPa for the unseeded mortar to 24 and 22 MPs for the mortars seeded with the XS130 and STE53, respectively. The evolution of the amorphous contents was determined by adding an internal standard before recording the powder patterns. In summary, alite and belite phase hydrations, from the crystalline phase content evolutions, are not significantly accelerated by C-S-H seedings at the studied ages of 1 and 28 d for these cements. Conversely, the hydration rates of tetracalcium alumino-ferrate and tricalcium aluminate were significantly enhanced. It is noted that the degrees of reaction of C4AF for the PC paste (w/c = 0.40) were 10, 30, and 40% at 1, 7, and 28 days. After C-S-H seeding, the values increased to 20, 45, and 60%, respectively...This research has been partly supported by a P18-RT-720 research grant, co-funded by ERDF, from Junta de Andalucía, Spain

An Unexpected Case of Opisthorchis felineus Infection Revealed during Liver Transplantation

A man with hepatitis B infection was admitted to Pisa University Hospital for hepatological evaluation, which revealed multiple cystic lesions and suggested a cirrhotic evolution. Treatment with Entecavir 0.5 mg/day was started, resulting in rapid viral load suppression and alanine aminotransferase normalization. After 10 years, imaging documented a single nodule of hepatocellular carcinoma (HCC), and a robot-assisted nodule resection was performed. One year later, HCC recurrence prompted orthotopic liver transplantation, during which the patient died because of the sudden rupture of the donor's organ and rapid multiorgan deterioration before retransplantation. During post-mortem liver examination, adult worms were evidenced within large biliary ducts, suggesting infection with Opisthorchis or Clonorchis spp. flukes. Sequencing of the ITS2 locus, following PCR amplification of DNA extracted from liver tissue, revealed 100% identity with the reference sequence of O. felineus. Infection of the patient with O. felineus was confirmed by the presence of specific IgG detected by ELISA in the patient's sera. Two major alkaline phosphatase serum levels peaks observed during the first two years of antiviral therapy support the hypothesis that O. felineus infection worsened liver function. This case report highlights the importance of a very careful screening of parasitic infections in solid organ transplantation candidates

Pair distribution function as a tool to characterize C-S-H gels

Portland cement (PC) is the most manufactured product in the world. However, cement industry is one of the major contributors for greenhouse gas emissions. For every ton of grey PC clinker, around 0.87 CO2 tons are released into the atmosphere. For this reason, alternative cements having similar performances to ordinary PC are needed. A recent work [1] has identified the use of supplementary cementitious materials (SCMs) as the most favourable approach for lowering CO2 emissions in the cement industry. The hydration reactions of tricalcium silicate, Ca3SiO5 (main phase of PC) consist of its dissolution, the precipitation of the nanocrystalline C-S-H gel, jointly with the formation of portlandite, Ca(OH)2 according to equation (1). C-S-H gel was described to be composed by defective nanocrystalline clinotobermorite, amorphous Ca(OH)2 and gel pore water [2]. The calcium hydroxide formed in reaction (1) can be employed to yield additional secondary C-(A)-S-H through the pozzolanic reaction with SCMs. Ca3SiO5 + 5.2H2O→1.2Ca(OH)2 +1/9[Ca11Si9O28(OH)2.8.5H2O] // 0.58[Ca(OH)2] // 2.37H2O (1) Crystalline C-S-H gel –nanocrystalline // amorphous . The analysis of nanocrystalline/amorphous phases in cement matrices which contain high amounts of crystalline phases is very challenging. Pair distribution function (PDF) in combination with synchrotron radiation is key to characterize cement pastes. This work focuses on the characterization of amorphous and nanocrystalline phases which are present in cement related pastes by total scattering PDF. We have studied a series of tricalcium silicate pastes blended with silica fume hydrated at four months and dicalcium silicate pastes hydrated at longer ages [3]. PDF data were collected at ALBA Synchrotron, beamline MSPD, see Figure 1.This research was funded by Ministry of Science (Spain), grant number PID2019-104378RJ-I0

Study of circulating antigens and antibodies in goat and sheep fascioliasis by electroimmunodiffusion test and micro-Elisa

Des antigènes circulants de F. hepática sont détectés par immunoélectro- diffusion et micro-Elisa respectivement chez 96,4 % et 88,4 % de 138 caprins et chez 91,8 % et 72,6 % de 73 ovins infectés naturellement alors que les anticorps ne sont retrouvés qu’en IED chez 8 % des caprins et 9,5 % des ovins. 60 animaux témoins non infectés ne comportent ni antigène ni anti corps. De plus dans l’infection expérimentale du lapin des antigènes circu lants sont détectés à 48 h, 5 jours et 20 jours, suggérant une relation avec le cycle du parasite et confirmant leur précocité d’apparition. La recherche d’antigène circulant apparaît comme une excellente méthode de diagnostic des animaux infectés.Circulating antigens were detected by electroimmunodiffusion test and micro-Elisa respectively in 96,4 % and 88,4 % sera of 138 goats and in 91,8 % and 72,6 % sera of 73 sheep with F. hepática natural infection. Whereas using the same methods antibody detection was positive respectively in 8 % and 9,5 % sera of the goats and negative in sheep. 60 controls without F. hepática infection had neither antigens nor antibodies in their sera. In rabbit experimental infection circulating antigens were detected after 48 hours, 5 and 20 days proving their early presence and suggesting a rela tionship between the parasite cycle. Circulating antigen detection appears to be a sensitive method of fascioliasis diagnosis in goats and sheep