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© 2020 Elsevier Ltd. All rights reserved., Background: Hereditary transthyretin-mediated amyloidosis is a rare, inherited, progressive disease caused by mutations in the transthyretin (TTR) gene. We assessed the safety and efficacy of long-term treatment with patisiran, an RNA interference therapeutic that inhibits TTR production, in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Methods: This multicentre, open-label extension (OLE) trial enrolled patients at 43 hospitals or clinical centres in 19 countries as of Sept 24, 2018. Patients were eligible if they had completed the phase 3 APOLLO or phase 2 OLE parent studies and tolerated the study drug. Eligible patients from APOLLO (patisiran and placebo groups) and the phase 2 OLE (patisiran group) studies enrolled in this global OLE trial and received patisiran 0·3 mg/kg by intravenous infusion every 3 weeks with plans to continue to do so for up to 5 years. Efficacy assessments included measures of polyneuropathy (modified Neuropathy Impairment Score +7 [mNIS+7]), quality of life, autonomic symptoms, nutritional status, disability, ambulation status, motor function, and cardiac stress, with analysis by study groups (APOLLO-placebo, APOLLO-patisiran, phase 2 OLE patisiran) based on allocation in the parent trial. The global OLE is ongoing with no new enrolment, and current findings are based on the interim analysis of the patients who had completed 12-month efficacy assessments as of the data cutoff. Safety analyses included all patients who received one or more dose of patisiran up to the data cutoff. This study is registered with ClinicalTrials.gov, NCT02510261. Findings: Between July 13, 2015, and Aug 21, 2017, of 212 eligible patients, 211 were enrolled: 137 patients from the APOLLO-patisiran group, 49 from the APOLLO-placebo group, and 25 from the phase 2 OLE patisiran group. At the data cutoff on Sept 24, 2018, 126 (92%) of 137 patients from the APOLLO-patisiran group, 38 (78%) of 49 from the APOLLO-placebo group, and 25 (100%) of 25 from the phase 2 OLE patisiran group had completed 12-month assessments. At 12 months, improvements in mNIS+7 with patisiran were sustained from parent study baseline with treatment in the global OLE (APOLLO-patisiran mean change -4·0, 95 % CI -7·7 to -0·3; phase 2 OLE patisiran -4·7, -11·9 to 2·4). Mean mNIS+7 score improved from global OLE enrolment in the APOLLO-placebo group (mean change from global OLE enrolment -1·4, 95% CI -6·2 to 3·5). Overall, 204 (97%) of 211 patients reported adverse events, 82 (39%) reported serious adverse events, and there were 23 (11%) deaths. Serious adverse events were more frequent in the APOLLO-placebo group (28 [57%] of 49) than in the APOLLO-patisiran (48 [35%] of 137) or phase 2 OLE patisiran (six [24%] of 25) groups. The most common treatment-related adverse event was mild or moderate infusion-related reactions. The frequency of deaths in the global OLE was higher in the APOLLO-placebo group (13 [27%] of 49), who had a higher disease burden than the APOLLO-patisiran (ten [7%] of 137) and phase 2 OLE patisiran (0 of 25) groups. Interpretation: In this interim 12-month analysis of the ongoing global OLE study, patisiran appeared to maintain efficacy with an acceptable safety profile in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Continued long-term follow-up will be important for the overall assessment of safety and efficacy with patisiran.

Fatigue is one of the most common symptoms in neurology, especially in MS patients with a prevalence of 65%. It is described as the most disabling symptom by 40% of MS patients. This study aimed to validate the Functional Assessment of Chronic Illness Therapy fatigue version (FACIT-F) and the F-2-MS scale, a new tool to distinguish between fatigue and fatigability.One hundred and fifteen patients with relapsing-remitting MS were enrolled. All patients completed a comprehensive neuropsychological battery, previously validated in MS. Fatigue was evaluated using the Fatigue Severity Scale (FSS), the Modified version of the Fatigue Impact Scale (MFIS), the Functional Assessment of Chronic Illness Therapy measure system (fatigue version) (FCIT-F), and a new tool for the assessment of fatigue and fatigability: the F-2-MS scale. Internal consistency was estimated with Cronbach's Alpha. For intergroup comparisons, Student's t-test and Pearson's chi-squared test were used. Pearson's correlation test was calculated for quantitative variables. Cohen's d was calculated to evaluate the effect size. Binary logistic regression was performed, considering the presence of fatigue as a criterion variable, and the FACIT-F and F-2-MS scores were added as predictor variables. ROC curves were also estimated. We conducted a confirmatory factor analysis for the F-2-MS scale, considering two latent factors.FACIT-F and F-2-MS showed high internal consistency. Both scales were highly correlated with MFIS and FSS, and showed a low correlation with Symbol Digit Modalities Test. There were significant differences between fatigued and non-fatigued patients on FACIT-F and F-2-MS scores with large effect sizes. Both scales showed AUC 0.90 and achieved a correct classification87%. Confirmatory factor analysis showed moderate evidence of two dimensions on the F-2-MS scale.The FACIT-F and F-2-MS scales showed appropriated psychometric properties to be used as fatigue measures in clinical and research settings, allowing a correct distinction between patients with and without fatigue, and contributing to the understanding of the complexities of fatigue in MS.

A new approach for the rapid manufacturing of end-of-arm robot tooling (EOAT) based on Venturi vacuum grippers is presented in this paper. It consists in designing and printing a monolithic tool th...

Resumen Objetivo Evaluar el nivel de implementacion de los protocolos asociados a la prevencion de la debilidad muscular adquirida en la unidad de cuidados intensivos (UCI), asi como la presencia del fisioterapeuta en distintas UCI de Espana. Metodo Estudio descriptivo, transversal realizado en 86 UCI de adultos de Espana entre los meses de marzo a junio de 2017. Se excluyeron UCI neuroquirurgicas y de grandes quemados. Se utilizo encuesta multirrespuesta que incluia preguntas sobre los protocolos de: control de glucemia, sedacion, valoracion del dolor, prevencion del delirium, manejo del delirium y movilizacion precoz. La encuesta fue rellenada a traves de un aplicativo protegido por usuario y contrasena. Analisis inferencial con t de Student o U de Mann-Whitney y de correlacion con Pearson o Rho de Spearman. Resultados El 89,5% de las UCI tenian protocolo de control de glucemia, con rango predominante de 110-140 mg/dl. El 74,4% evaluaban el nivel de sedacion, si bien solo tenian protocolos de sedacion el 36% de ellas. Con relacion a la valoracion del dolor se realizaba en el 73,7% de los pacientes comunicativos, mientras que en los no comunicativos solo era del 47,5%. Solo el 37,2% realizaban screening diario para detectar el delirium, y disponian de protocolos de prevencion del delirium el 31,4% de las UCI, del manejo del delirium el 26,7% y de movilizacion precoz el 14% de las UCI. En el 34,9% de los casos se solicita interconsulta al servicio de rehabilitacion. Conclusiones La implementacion de los diferentes protocolos asociados a la prevencion de la debilidad muscular adquirida ha sido elevada en relacion con los protocolos de control de glucemia, valoracion del nivel de sedacion y del dolor de pacientes comunicativos, mientras que baja en los de movilizacion precoz y screening y prevencion del delirio. Asimismo, es poco frecuente la presencia del fisioterapeuta en la UCI.

Background Antibodies to the aquaporin-4 (AQP4) water channel in neuromyelitis optica spectrum disorder (NMOSD) are reported to trigger the complement cascade, which is implicated in astrocyte damage and subsequent neuronal injury. The PREVENT study demonstrated that the terminal complement inhibitor eculizumab reduces adjudicated relapse risk in patients with anti-AQP4 immunoglobulin G-positive (AQP4+) NMOSD. The objective of this analysis was to evaluate the efficacy of eculizumab in reducing relapse risk and its safety in AQP4+ NMOSD across clinically relevant subgroups in PREVENT. Methods In the randomized, double-blind, time-to-event, phase 3 PREVENT trial, 143 adults received eculizumab (maintenance dose, 1200 mg/2 weeks) or placebo (2:1), with stable-dose concomitant immunosuppressive therapy (IST) permitted (except rituximab and mitoxantrone). Post hoc analyses of relapses and adverse events were performed for prespecified and post hoc subgroups based on concomitant IST and prior rituximab use, demographic and disease characteristics, and autoimmune comorbidity. Results The significant reduction in relapse risk observed for eculizumab versus placebo in the overall PREVENT population was consistently maintained across subgroups based on concomitant IST and previous rituximab use, age, sex, region, race, time since clinical onset of NMOSD, historical annualized relapse rate, baseline Expanded Disability Status Scale score, and history of another autoimmune disorder. The serious infection rate was lower with eculizumab than placebo regardless of rituximab use in the previous year, concomitant IST use, or history of another autoimmune disorder. Conclusion Across a wide range of clinically relevant AQP4+ NMOSD patient subgroups in PREVENT, eculizumab therapy was consistently effective versus placebo in reducing relapse risk, with no apparent increase in serious infection rate. Trial registration NCT01892345 (ClinicalTrials.gov).

© 2020 by the authors., The effect of two precursors (slag and fly ash), different particle size distribution, and three types of aggregate (siliceous sand, limestone, and recycled concrete) on alkali-activated material (AAM) mortar rheology were studied and compared to their effect on an ordinary Portland Cement (OPC) mortar reference. Stress growth and flow curve tests were conducted to determine plastic viscosity and static and dynamic yield stress of the AAM and OPC mortars. In both OPC and AAM mortars, a reduction of the aggregate size induces a rise of the liquid demand to preserve the plastic consistency of the mortar. In general terms, an increase of the particle size of the siliceous aggregates leads to a decrease of the measured rheological parameters. The AAM mortars require higher liquid/solid ratios than OPC mortars to attain plastic consistency. AAM mortars proved to be more sensitive than OPC mortars to changes in aggregate nature. The partial replacement of the siliceous aggregates with up to 20% of recycled concrete aggregates induced no change in mixing liquid uptake, in either AAM or OPC mortars. All the AAM and OPC mortars studied fitted to the Bingham model., This study was funded by AEI-/FEDER/UE under projects BIA2013-47876-C2-1-P and BIA2016-77252-P. Marta Palacios thanks Consejería de Educación e Investigación (Comunidad de Madrid) for funding the 2016-T1/AMB-1434 project in the frame of “Ayudas de Atracción de Talento Investigador” and MCIU/AEI/FEDER, UE for funding the RTI2018-099326-A-I00 project.

Objetivo: Adaptar la ICU Mobility Scale (IMS) al ámbito de las unidades de cuidados intensivos (UCI) de España y evaluar las propiedades métricas de la IMS versión española (IMS-Es). Método: Estudio descriptivo de carácter métrico desarrollado en dos fases. Fase 1: adaptación al español de la IMS mediante equipo de enfermeras y fisioterapeutas (traducción, piloto, retrotraducción y acuerdo). Fase 2: análisis de propiedades métricas (validez convergente, divergente y predictiva, fiabilidad interobservador, sensibilidad y diferencia mínima importante) de la IMS-Es. Se registraron características de los pacientes (Barthel, Charlson, IMC, sexo), nivel de sedación/agitación (RASS), estancias en UCI y hospital, supervivencia, calidad de vida (SF-12), debilidad muscular (MRC-SS) y movilidad (IMS-Es) en los pacientes del estudio multicéntrico nacional MOviPre. Resultados Tras obtener la IMS-Es, se implementó en 645 pacientes de 80 UCI españolas entre abril y junio de 2017. Validez convergente: moderada correlación entre IMS-Es y MRC-SS (r = 0,389; p < 0,001) y comparación significativa entre grupos con y sin debilidad adquirida en la UCI (p < 0,001). Validez divergente: no correlación entre IMS-Es e IMC (r [IC 95%]: −0,112 [−0,232 a 0,011]), peso (r [IC 95%]: −0,098 [−0,219 a 0,026]), Charlson (r [IC 95%]: −0,122 [−0,242 a 0,001]) y Barthel (r [IC 95%]: −0,037 [−0,160 a 0,087]) y sin diferencias entre sexos (p = 0,587) ni categorías de IMC (p = 0,412). Validez predictiva: moderadas y significativas correlaciones con estancia en hospital post-UCI (r [IC 95%]: −0,442 [−0,502 a −0,377]) y componente físico del SF-12 (PCS) (r [IC 95%]: 0,318 [0,063 a 0,534]); pacientes sin movilización activa en UCI mayor riesgo de mortalidad hospitalaria (OR [IC 95%]: 3,769 [1,428 a 9,947]). Fiabilidad interobservador: muy buena concordancia entre enfermeras (CCI [IC 95%]: 0,987 [0,983 a 0,990]) y entre enfermera-fisioterapeuta (CCI [IC 95%]: 0,963 [0,948 a 0,974]). Sensibilidad al cambio: efecto pequeño al alta de UCI (d = 0,273) y moderado a los 3 meses del alta hospitalaria (d = 0,709). Diferencia mínima importante: punto de corte de la diferencia de 2 puntos, sensibilidad del 91,1% y especificidad del 100,0%. Conclusiones: La IMS-Es es útil, válida y fiable para ser implementada por enfermeras de UCI y por fisioterapeutas al valorar la movilidad de los pacientes críticos. Objective: To adapt the ICU Mobility Scale (IMS) to the area of intensive care units (ICU) in Spain and to evaluate the metric properties of the Spanish version of the IMS (IMS-Es). Method: Descriptive metric study developed in two phases. Phase 1, adaptation to Spanish of the IMS by a team of nurses and physiotherapists (translation, pilot, backtranslation and agreement). Phase 2, analysis of metric properties (convergent, divergent and predictive validity, interobserver reliability, sensitivity and minimum important difference) of the IMS-Es. Patient characteristics (Barthel, Charlson, BMI, sex), sedation/agitation level (RASS), ICU and hospital stays, survival, quality of life (SF-12), muscle weakness (MRC-SS) and mobility (IMS-Es) were recorded in the patients of the MOviPre national multicentre study. Results After obtaining the IMS-Es, it was implemented in 645 patients from 80 Spanish ICUs between April and June 2017. Convergent validity: moderate correlation between IMS-Es and MRC-SS (r = .389; P < .001) and significant comparison between groups with and without ICU-acquired weakness (P < .001). Divergent validity: no correlation between IMS-Es and BMI [r (95% CI): −.112 (−.232 to .011)], weight [r (95% CI): −.098 (−.219 to .026)], Charlson [r (95% CI): −.122 (−.242 to .001)] and Barthel [r(95% CI): −.037 (−.160 to .087)] and no differences between sexes (P = .587) or BMI categories (P = .412). Predictive validity: moderate and significant correlations with post-ICU hospital stay [r (95% CI): −.442 (−.502 to −.377)] and physical component of SF-12 (PCS) [r (95% CI): .318 (.063 to .534)]; patients without active mobilisation in ICU increased risk of hospital mortality [OR (95% CI): 3.769 (1.428 to 9.947)]. Interobserver reliability: very good concordance between nurses [CCI (95% CI): .987 (.983 to .990)] and nurse-physiotherapist [CCI (95% CI): .963 (.948 to .974)]. Sensitivity to change: small effect on discharge from ICU (d = .273) and moderate effect at 3 months after hospital discharge (d = .709). Minimal important difference: 2-point difference cut-off point, 91.1% sensitivity and 100.0% specificity. Conclusions: The IMS-Es is useful, valid and reliable for implementation by ICU nurses and physiotherapists in assessing the mobility of critical patients. Sin financiación No data JCR 2020 0.239 SJR (2020) Q3, 31/61 Advanced and Specialized Nursing No data IDR 2020 UEM

The fast loss of fluidity of sodium silicate-activated slag (SS-AAS) systems have been widely studied in the literature. In this study, the rheology of these cements has been correlated with the evolution of the reaction products formed over time. For this purpose, a combination of experimental characterization techniques, to study the pore solution composition and microstructure of SS-AAS pastes and hermodynamic calculations have been applied. The initial precipitation of ill-defined N-A-S-H and C-N-A-S-H producta leads to a fast increase of the storage modulus after 40 min of reaction. These products are formed from the reaction of the Na+ ions and silicate ions of the activator with the Ca2+ and aluminate species dissolved from the slag. However, when a shear is applied, the structure breaks down and fluidity is recovered, that infers that the attractive forces between the particles are low at the early stages of hydration., The authors thank Prof. Habert (ETHZ) for constructive discussion. Dr. Francesco Caruso (SIK-ISEA) is thanked for helping to develop a protocol for the ICP-OES measurements. Dr. M. Palacios acknowledges Consejería de Educacion ´ e Investigacion ´ (Comunidad de Madrid) for funding the 2016-T1/AMB-1434 project in the frame of “Ayudas de Atraccion ´ de Talento Investigador” and MCIU/AEI/FEDER, UE for funding the RTI2018-099326-A-I00 project. Prof. F. Puertas thanks the Spanish Ministry of Science and Innovation for funding BIA2013-47876- C2-1-P and BIA2016-77252-P projects.

Viscosity modifying agents (VMAs) are essential ingredients for the production of flowable cement-based materials. This paper presents an overview of commonly used VMAs and attempts to shed some light on the underlying physics at the origin of their mechanisms of action. The main molecular parameters of VMA controlling the rheological properties of the cement pore solution are highlighted. As the mechanisms of action of VMAs in cement-based materials are closely related to their affinity with the surface of cement particles, the adsorption of the main VMA types is discussed. The effect of VMAs on flow properties and stability of cement-based materials is presented for VMAs added without any superplasticizer, and then in systems incorporating both VMAs and superplasticizers. Finally, the effect of VMAs in enhancing concrete properties to secure adequate performance of different construction applications, and perspectives for future developments of novel cement-based materials made with VMAs are showcased.

The article “Relating early hydration, specific surface and flow loss of cement pastes”, written by “Sara Mantellato, Marta Palacios, Robert J. Flatt”, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 4 January 2019 without open access.

Pore solution compositions dictate the kinetics of cement hydration. Their characterization can therefore provide essential insight into the rate at which cement phases hydrated. One of the most widely used techniques to characterize pore solution composition is ICP-OES. However, cement literature generally overlooks the fact that high accuracy from this technique can only be obtained if proper accounting for matrix effects is carried out. We first present a new method for such a technique, demonstrating that limits of quantification down to 34 times lower than the ones generally reported can be obtained. This method is applied to the study of the early hydration of admixed cement pastes. In particular, we highlight the formation of nanoparticles that may have different origins. The formation can be expected to have important consequences on the working mechanisms of some chemical admixtures.

Background Intensive care unit–acquired muscle weakness (ICUAW) has an incidence of 40–46%. Early mobilisation is known to be a protective factor. Objective The aim of the study was to identify the incidence of ICUAW in Spain and to evaluate variables likely to contribute to the development of ICUAW. Methods A 4-month, prospective observational multicentre cohort study was conducted on patients receiving invasive mechanical ventilation for at least 48 h. Data were collected from ICU day 3 until ICU discharge. The primary outcome was presence of ICUAW (diagnosed using the Medical Research Council [MRC] scale). The secondary outcome was nurse–patient ratio, physiotherapist availability, analgesia, sedation and delirium management, glycaemic control, and daily level of mobility during the ICU stay as per the ICU Mobility Scale. A logistic regression model was constructed based exclusively on days 3–5 of the ICU stay. Results The data of 642 patients were analysed from 80 ICUs, accounting for 35% of all ICUs in Spain. The incidence of ICUAW was 58% (275 of 474 patients; 95% confidence interval [CI] [53–62]). The predictors for ICUAW were older age (odds ratio [OR] = 1.01; 95% CI [1.00–1.03]) and more days with renal replacement therapy (OR = 1.01; 95% CI [1.00–1.02]). The protective factors for ICUAW were male gender (OR = 0.58; 95% CI [0.38–0.89]), higher Barthel Index (showing prehospital functional independence) (OR = 0.97; 95% CI [0.95–0.99]), more days of being awake and cooperative (defined by a feasible MRC assessment) (OR = 0.98; 95% CI [0.97–0.99]), presence of delirium (OR = 0.98; 95% CI [0.97–0.99]), and more days with active mobilisation (ICU Mobility Scale ≥ 4) (OR = 0.98; 95% CI [0.97–0.99]). Conclusions The risk factors for ICUAW were functional dependence before admission, female gender, older age, and more days on renal replacement therapy. The protective factors for ICUAW were feasibility of MRC assessment, the presence of delirium, and being actively mobilised during the first 5 days in the ICU.

Flow loss in superplasticized systems has been mainly explained in qualitative and comparative ways over the past years. This is due to the intrinsic complexity of the underlying mechanism involving a change in the agglomeration degree as a result of cement hydration. The lack of robust and reliable experimental methodologies must have additionally discouraged researchers from attempting to understand the phenomena of flow loss in quantitative terms. Thanks to new analytical methods, it was possible to prove that after the so-called onset point, yield stress increases exponentially with the increase of both heat rate measured by isothermal calorimetry and specific surface. This paper also identifies the existence of a direct proportionality between the increase of heat rate and the increase of specific surface area during the acceleration period, most likely reflecting the nucleation and growth nature at this stage of the cement hydration., Materials and Structures, 52 (1), ISSN:1359-5997, ISSN:0025-5432, ISSN:1871-6873

El presente trabajo fin de grado (TFG) está orientado al estudio de la identidad profesional de los docentes. Específicamente, centramos la mirada en las vivencias y experiencias que tenemos a lo largo de nuestro recorrido como aprendices. Esto influye directa o indirectamente en la persona que somos actualmente y, en consecuencia, en el profesional que somos y en cómo actuamos ante determinadas situaciones tanto dentro de nuestra aula como de nuestro centro escolar. en esta investigación se realiza un estudio de caso de cuatro maestras con el objetivo de analizar cómo influyen las experiencias y vivencias que han tenido en su infancia, sobre todo en el ámbito escolar, en la identidad docente actual que presentan cada una de ellas. El estudio de casos se lleva a cabo con un método de investigación cualitativa, concretamente la narrativa autobiográfica, la cual permite explorar la historia de vida y la trayectoria profesional de las maestras.

The aim of the present research is to ascertain the effect of the nature and concentration of the alkaline activator and temperature on the rheological behaviour of alkali-activated fly ash (AAFA) pastes. Furthermore, the reaction process of fly ash has been investigated from rheological measurements. Results have shown that the increase of the activator concentration and the temperature leads to an increase of yield stress and apparent viscosity, mainly at temperatures above 65 °C when dissolution of fly ash and precipitation of hydration products is raised. In general, similar activation energies were determined for alkali-activated fly ash pastes, regardless of the concentration and silica modulus of the activator, concluding that the underlying reaction mechanism is the same independently on the nature of the activating solution., Prof. F. Puertas thanks MINECO (Spanish Ministry) for funding BIA2013-47876-C2-1-P project. Dr. M. Palacios acknowledges Consejería de Educación e Investigación (Comunidad de Madrid) for funding the 2016-T1/AMB-1434 project in the frame of “Ayudas de Atracción de Talento Investigador”.

The effect of sample preparation, including degassing conditions and method to stop cement hydration, on the specific surface area (SSABET) of synthetic ettringite (AFt) was studied. Dehydration of AFt occurs even at moderate temperatures under N2 flow (0% RH). However, partial dehydration associated to a loss of up to 12 water molecules does not imply a change in SSABET. A mild degassing 16 h at 40 °C under N2 flow is suggested mainly to preserve the chemical composition and morphology of calcium sulfate carrier. At higher temperatures, ettringite dehydration involves a significant modification of its crystalline structure and increase of the SSABET. Typical protocols to stop cement hydration, solvent exchange and freeze-drying, lead to larger water removal from the AFt and crystallinity reduction, being significantly higher when the latter is applied. However, only freeze-drying leads to a moderate increase of the synthetic AFt SSABET.

A micro-reactor approach, developed previously, is used to study the reactions of slag in alkaline media. Micron-sized gaps are milled in slag grains using a focused ion beam (FIB) and subsequently filled with alkaline solutions, leading to dissolution and hydration of the slag. After the hydration is stopped, a scanning electron microscope (SEM) is used to image the gaps. We present the effect of pH and nature of the alkaline solution on the slag dissolution and the hydrate morphology. The results obtained in this study confirm that the presence of aluminum and calcium in solution has a strong retarding effect on the slag dissolution. A major implication of these results is that in blended cements, the reactivity of slag probably suffers from the ions released by cement into solution. We show that strongly adsorbing superplasticizers inhibit the dissolution of slag, but only at lower alkali concentrations and C–S–H seeds may also inhibit the dissolution of slag under certain experimental conditions. The obtained results are compared and contrasted with results obtained for alite and tricalcium silicate previously reported in the literature.

The particle size distribution (PSD) and specific surface area (SSA) are complementary parameters that give information about the fineness of a powder. They can be combined to get information about the state of agglomeration and morphology of a powder. The state of agglomeration of a powder has an influence on its dispersibility, its packing and, hence, the rheology of a suspension; this is of critical importance in the fluidity of cementitious materials.

In this work, we study the effect of non-adsorbing polymers with molar masses varying over several decades in both dilute and semi-dilute regimes on the yield stress of cement and calcite pastes. In both suspensions, we measure an increase of yield stress, the magnitude of which mainly depends on the polymer concentration regimes. From interparticle force calculations, we show that non-adsorbing polymers are at the origin of interparticle attractive depletion forces. In the absence of superplasticizers, Van der Waals attractive forces are the dominant flocculating mechanism in the system and depletion forces resulting from non-adsorbing polymers are negligible. The repulsive forces that result from superplasticizers' steric contribution increase the average interparticle distance and therefore decrease the magnitude of the attractive van der Waals forces. In this latter system, attractive depletion forces induced by non-adsorbing polymers become important and greatly contribute to the flocculation mechanism.

The specific surface area (SSA) of anhydrous cement has a direct impact on its reactivity and on the properties of fresh and hardened concrete. However, measuring this physical parameter is non-trivial. The choice of the degassing conditions (temperature, pressure and time) is essential for reliable SSA measurements by nitrogen adsorption because of the dehydration of the gypsum it contains. Such dehydration involves a significant increase of the SSABET, whereas Blaine test is poorly sensitive to the hydration state and structural modification of the calcium sulfate carrier. Because of this, SSABET values may be more variable than Blaine fineness. More consistent SSABET results could be obtained by degassing anhydrous cement samples at 40 °C under N2 flow for 16 h, as at these conditions the cement composition is preserved.

Con motivo de los tres ejercicios contables en que se dividía el año natural, fechados en la Candelaria, la Ascensión y Todos los Santos, los templarios daban cuenta de su gestión a sus clientes, entregándoles un resumen en cada ejercicio en el que aparecía la posición deudora o acreedora de la Orden frente a ellos que denominamos extracto de cuenta. En este trabajo se realiza un análisis descriptivo y cualitativo del contenido del extracto de la cuenta de la Candelaria o extracto de la cuenta de cobros y pagos realizados por el tesorero del Temple para Blanca de Castilla, reina madre de Francia, del 2 de febrero de 1243, que nos ofrece un ejemplo de la rendición de cuentas del Temple a uno de sus clientes. Documento en el que existe cierta discusión acerca de la posible existencia de vestigios del uso de la partida doble. Calendar year was divided in three accounting periods, according to the Candelaria, the Ascension and the Feast of All Saints so that, on those dates, the Templars reported accountability of their management to their customers, and supplying them a summary account on the position of debit or credit of the Order opposite them, that we call the extract of the account. This paper presents a descriptive and qualitative analysis of the contents of extract of Candelaria´s account or extract of collection and payment management performed by the treasurer of the Temple to Blanca de Castilla, Queen mother of France, on 2nd of February 1243, which provides an example of accountability of the Temple to one of its customers. About this document there is some discussion of whether there are traces of the use of double-entry accounting.

We used a combination of experimental and modelling techniques to study the effect of NaAlO2 on C3S hydration. pH sensitive inhibition of C3S hydration occurred at an early age of reaction, but was followed by an increased amount of hydrates formed later. Most results suggest that aluminates hinder C3S dissolution. It is hypothesised that this takes place in active dissolution areas, present with a higher density on finer particles. Annealing reduces their number and increases retardation for a given dosage of aluminates. The view that aluminates act by hindering dissolution is supported by molecular dynamics (MD) simulations. They establish that aluminates can adsorb on the hydroxylated C3S mainly through strong ionic interactions between aluminate and calcium ions on the surface of silicate. Upon progress of hydration and at higher pH values, the binding strength of aluminates to the hydroxylated C3S decreases so that its passivating effect, and retardation, are reduced.

Micrometer and submicrometer size features were prepared in poly(methyl methacrylate) based polymer blends by hot-embossing using a customized silicon master. The surface patterns were design to contain particular functionalities for wetting in combination by the additive included in the polymer blend. More precisely copolymers containing MMA units and either a hydrophobic fluorinated monomer or a hydrophilic monomer was incorporated in the polymer mixture prior to embossing. Surface segregation using the appropriated annealing conditions allowed us to vary the interfacial chemical composition. Thus, we demonstrate that the wettability of the surface can be varied as a function of both the low surface energy additive and the annealing carried out whilst maintaining the overall surface topography.

Nowadays the blended cements acquire the merit of high significance due to the thermal, energetic and ecological demands for ordinary Portland cement (PC) production. Metakaolin as a partial substitute of PC represents important pozzolana contributing to production of effective cement composites with high quality. Pozzolanic reaction of metakaolinite with PC in the presence of water is main reason of this statement. Comparison of three types of metakaolin sand (fineness below 60 μm) with different metakaolinite content (31–40 mass%) is presented in this study. The substitution of PC with metakaolin sand of the maximal metakaolinite content (40 mass%) leads to the highest compressive strengths of relevant composites. This is valid for composites with the highest substitution of PC by metakaolin sand in specimens (20 and 40 mass%). The best effectiveness of pozzolanic reaction is given especially by the highest consumption of portlandite which represents composite with the maximal metakaolinite content in metakaolin sand (40 mass%) and the higher substitution level of PC by metakaolin sand in specimens. This fact is connected with the improvement of pore structure parameters resulting in the pore structure refinement as well as permeability decreases. Both 29Si MAS NMR and 27Al MAS NMR spectra of metakaolin sands and respective composites confirm the most intense pozzolanic reaction in the case of metakaolin sand with the highest metakaolinite content (40 mass%). The results are properly supplemented by scanning electron microscopy (SEM) identifying the formed typical phases. The study has shown that metakaolin sand with reduced metakaolinite contents is also applicable as a pozzolanic addition to PC in the on-coming building practice.

In part 1, the effect of different polycarboxylate ether (PCE) admixtures with Portland-based binder (OPC) and calcium aluminate cement (CAC) pastes has been studied; indicating a low CAC–PCEs compatibility. In this part, 2, the effect of PCE admixtures with different molecular structure on the hydration and microstructural development of CAC pastes has been studied. The findings showed that the PCE admixtures used retarded CAC hydration and this effect is independent of the admixture carboxylate/ester ratio. The results obtained have proven that the presence of PCE admixtures in OPC and CAC pastes does not modify the nature of hydrates formed. However, in CAC pastes, the presence of PCE admixture has an important effect on the amount of hydrates generated, it being 45% lower at the same time than in CAC pastes without admixture.

In calcium aluminate cements (CAC), it is recommended to work with low water/cement ratios (for example using superplasticizers admixtures) to avoid the negative effects of metastable hexagonal hydrate conversion to stable cubic ones. The present work studies the compatibility between CAC and three polycarboxylate ether (PCE) admixtures with different structures. The C/E ratio of PCE admixtures was less important to the adsorption values in CAC suspensions than those of Portland-based binder (OPC). The more positive zeta potential in the CAC pastes may be the reason why these admixtures (regardless of their C/E ratio) adsorb onto cement particles with a different conformation than observed in OPC pastes. The presence of PCE admixtures decreases yield stress of CAC pastes at a lower dosage than that needed for OPC pastes. However, after 15 min CAC pastes with PCE admixtures lose their fluidity, an indication of the scant compatibility between these materials.

The optimal temperature transformation of kaolin sand to metakaolin sand (MKS) resulting in complete conversion of kaolinite to pozzolanic active metakaolinite (MK) is 650°C in the time of 1 hour. To obtain information on mechanism of pozzolanic reaction in studied binary system, the cement pastes with two MKS at substitution level of Ordinary Portland cement (OPC) with MKS by 10, 20 and 40 wt. % corresponding to 3.6 - 16.0 % MK content in pastes, were tested. Pozzolanic reaction of MK with hydrating OPC was clearly confirmed mainly by XRD and thermal analyses. This process accompanied with gradual reduction of Ca(OH)2 content was the most intense in pastes with the highest MK contents (14.4 and 16.0 %). The decrease of micropore and total pore volume until MK content in paste of 7.2 % is measure of pore structure improvement specified as pore structure refinement. Until MK content of 8.0 % in paste, micropores portion with pore radius less than 10 nm rises and pore radius in the range between 10 and 100 nm declines. Resulted compressive strengths of related cement pastes with various MK content were comparable with strengths of pastes without MK. The obtained results confirmed that MKS can be used as promising additive in OPC to form prospective blended cements.

Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of 29Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured., Nature Communications, 7, ISSN:2041-1723

Viscosity-modifying admixtures (VMAs) are essential to control the stability and cohesion of modern concrete. This chapter focuses on polymeric VMAs as they allow a higher variability of structural variations. They enhance the stability of the mix by increasing one or several rheological parameters at the same time. Their mechanism of action depends on the nature of the VMA and the presence of other admixtures in the mix. In general, water retention admixtures delay cement hydration while the influence of other VMAs on cement hydration depends on its chemical composition. In practice, problems of incompatibility between specific combinations of VMAs and superplasticizers must be avoided. These could lead to a quick loss of fluidity without much improvement in the stability of concrete. The understanding of the mechanism of action of the different types of polymers may decrease the risk of having such problems on site.

Chemical admixtures are nowadays very important for concrete design. This chapter presents an overview of the chemical structures of different organic chemical admixtures, ranging from small organic compounds to large polymers having a certain polydispersity, and of both natural and synthetic origin. The choice is guided by the fact that this is where the real added value of molecular structure comes into play in terms of design of new or modified chemical admixtures. Such admixtures offer the greatest possibility to chemists to modify properties and target improved performance by specific exploitation of structure/property relationships. The overview gives a basis for better understanding of the working mechanisms of these admixtures.

For first time, an experimental and computational study has been conducted to define a structural model for the C-A-S-H gel forming in alkali-activated slag (AAS) pastes that would account for the mechanical properties of these materials. The study involved a comparison with the C-S-H gel forming in a Portland cement paste. The structure of the C-A-S-H gels in AAS pastes depends on the nature of the alkali activator. When the activator is a NaOH, the structure of the C-S-H gel falls in between tobermorite 1.4 nm with a mean chain length of five, and tobermorite 1.1 nm with a mean length of 14. When waterglass is the activator the structure of the C-A-S-H gel is indicative of the co-existence of tobermorite 1.4 nm with a chain length of 11 and tobermorite 1.1 nm with a chain length of 14. This very densely packed structure gives rise to excellent mechanical properties.

The textural and mechanical characterization of C-S-H gels formed from the hydration of pure T1-C3S, β-C2S and their blends are studied by Nitrogen sorption and nanoindentation experiments. The surface area and nanoporosity of C-S-H gels formed from the hydration of β-C2S and the 30-70 (T1-C3S and β-C2S mixture) are higher than those from hydration of T1-C3S, and 70-30, with the difference decreasing with hydration age. Such changes are well supported by findings of nanoindentation study, which shows the greater relative volume of C-S-H phases with lower densities in the β-C2S and the 30-70 pastes. With the increase in hydration age, the relative volume of C-S-H phases with higher densities increased at the expenses of those with lower density. Important quantitative correlations were found among these textural characteristics and the mean chain length, determined from 29Si magic-angle-spinning (MAS) NMR, of the C-S-H gels.

The hydration processes of T1-C3S and β-C2S and their mixtures 70-30 and 30-70 (% in weight) have been followed by conduction calorimetric studies. The synergy of the T1-C3S and β-C2S hydration reactions, across their mixtures in proportions of 70-30 and 30-70, has been studied through the quantification of the portlandite carried out by thermogravimetric analysis. The hydration reactions and the quantitative evolution of all the components with the time have been studied during a period of 90 days at the room temperature of the laboratory. The microstructure was studied by scanning electron microscopy, the type of silicate tetrahedron, and mean chain length of the C–S–H gel by 29Si magic angle spinning nuclear magnetic resonance, and the porosity and pore-size distribution by mercury intrusion porosimetry. The main results showed that the hydraulic activity of the β-C2S strongly increased in the presence of T1-C3S, mainly at early stages, avoiding its inactive induction period. As a consequence of the increase of the hydraulic activity of the β-C2S, the pore microstructure is refined and the surface area is diminished.