1,096 research outputs found
Study of alkaline hydrothermal activation of belite cements by thermal analysis
The effect of alkaline hydrothermal activation of class-C fly ash belite cement was studied using thermal analysis (TG/DTG) by determining the increase in the combined water during a period of hydration of 180 days. The results were compared with those obtained for a belite cement hydrothermally activated in water. The two belite cements were fabricated via the hydrothermal-calcination route of class-C fly ash in 1 M NaOH solution (FABC-2-N) or demineralised water (FABC-2-W). From the results, the effect of the alkaline hydrothermal activation of belite cement (FABC-2-N) was clearly differentiated, mainly at early ages of hydration, for which the increase in the combined water was markedly higher than that of the belite cement that was hydrothermally activated in water. Important direct quantitative correlations were obtained among physicochemical parameters, such as the combined water, the BET surface area, the volume of nano-pores, and macro structural engineering properties such as the compressive mechanical strength
Materiales cementicios utilizados en el almacenamiento español de residuos de media y baja radiactividad
BWR and PWR cemented matrices to confine low and medium simulated liquid radioactive wastes have been submitted to the leaching process in de-ionized water at 20ºC and 40ºC, to obtain the medium leachability index (L) and the effective diffusion coefficient (De) of different ions. Otherwise, it has been studied the associated expansion of the backfilling mortar of the concrete containers of the Spanish repository of these wastes, due to a possible attack of the sulfate ions coming from the cemented matrices.Matrices cementicias confinantes tipo BWR y PWR de residuos simulados de baja y media radiactividad se han sometido a procesos de lixiviación en agua desionizada a 20ºC y 40ºC, obteniéndose los índices medios de lixiviación (L) y el coeficiente de difusión efectiva (De) de algunos iones. Por otra parte, se ha estudiado la expansión asociada a un mortero de relleno constitutivo del depósito de almacenamiento de los residuos, por posible ataque de los iones SO4-2 procedentes de las matrices
Influencia de la conductividad y fuerza iónica de soluciones sintéticas que simulan la fase acuosa del hormigón en el fenómeno de la corrosión de armaduras
Polarization Resistance (Rp) has been the electrochemical technique employed to study quantitatively the influence of Cl- and OH- ions on the corrosion of steel reinforcing, in a synthetic aqueous medium of similar composition to those of the concrete pore solution. Ionic strength, resistivity and their variations in function of CI- and OH- concentration have been chosen as more interesting solution parameters, together with intensity and potential corrosion measurements. The results showed the clear antagonistic role played by CI- and OH- ions on the corrosion process, which decreased as ionic strength increased.Este trabajo presenta el estudio cuantitativo, mediante la técnica de Resistencia de Polarización (Rp), de la influencia de los iones Cl- y OH- en la corrosión de armaduras de acero, en un medio acuoso sintético de similar composición al contenido en los poros del hormigón. Fuerza iónica, conductividad (resistividad) y sus variaciones en función de la concentración de dichos iones, han sido los parámetros de interés escogidos para la evaluación del proceso, además de las medidas de intensidad y potenciales de corrosión. Los resultados muestran claramente el antagonismo de los iones Cl - y OH- , cuyo carácter agresivo o protector disminuye a medida que aumenta la fuerza iónica del medio
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The dipeptidyl peptidase IV inhibitors vildagliptin and K-579 inhibit a phospholipase C: a case of promiscuous scaffolds in proteins.
The long term side effects of any newly introduced drug is a subject of intense research, and often raging controversies. One such example is the dipeptidyl peptidase-IV (DPP4) inhibitor used for treating type 2 diabetes, which is inconclusively implicated in increased susceptibility to acute pancreatitis. Previously, based on a computational analysis of the spatial and electrostatic properties of active site residues, we have demonstrated that phosphoinositide-specific phospholipase C (PI-PLC) from Bacillus cereus is a prolyl peptidase using in vivo experiments. In the current work, we first report the inhibition of the native activity of PI-PLC by two DPP4 inhibitors - vildagliptin (LAF-237) and K-579. While vildagliptin inhibited PI-PLC at micromolar concentrations, K-579 was a potent inhibitor even at nanomolar concentrations. Subsequently, we queried a comprehensive, non-redundant set of 5000 human proteins (50% similarity cutoff) with known structures using serine protease (SPASE) motifs derived from trypsin and DPP4. A pancreatic lipase and a gastric lipase are among the proteins that are identified as proteins having promiscuous SPASE scaffolds that could interact with DPP4 inhibitors. The presence of such scaffolds in human lipases is expected since they share the same catalytic mechanism with PI-PLC. However our methodology also detects other proteins, often with a completely different enzymatic mechanism, that have significantly congruent domains with the SPASE motifs. The reported elevated levels of serum lipase, although contested, could be rationalized by inhibition of lipases reported here. In an effort to further our understanding of the spatial and electrostatic basis of DPP4 inhibitors, we have also done a comprehensive analysis of all 76 known DPP4 structures liganded to inhibitors till date. Also, the methodology presented here can be easily adopted for other drugs, and provide the first line of filtering in the identification of pathways that might be inadvertently affected due to promiscuous scaffolds in proteins
Exploring the randomness of Directed Acyclic Networks
The feed-forward relationship naturally observed in time-dependent processes
and in a diverse number of real systems -such as some food-webs and electronic
and neural wiring- can be described in terms of so-called directed acyclic
graphs (DAGs). An important ingredient of the analysis of such networks is a
proper comparison of their observed architecture against an ensemble of
randomized graphs, thereby quantifying the {\em randomness} of the real systems
with respect to suitable null models. This approximation is particularly
relevant when the finite size and/or large connectivity of real systems make
inadequate a comparison with the predictions obtained from the so-called {\em
configuration model}. In this paper we analyze four methods of DAG
randomization as defined by the desired combination of topological invariants
(directed and undirected degree sequence and component distributions) aimed to
be preserved. A highly ordered DAG, called \textit{snake}-graph and a
Erd\:os-R\'enyi DAG were used to validate the performance of the algorithms.
Finally, three real case studies, namely, the \textit{C. elegans} cell lineage
network, a PhD student-advisor network and the Milgram's citation network were
analyzed using each randomization method. Results show how the interpretation
of degree-degree relations in DAGs respect to their randomized ensembles depend
on the topological invariants imposed. In general, real DAGs provide disordered
values, lower than the expected by chance when the directedness of the links is
not preserved in the randomization process. Conversely, if the direction of the
links is conserved throughout the randomization process, disorder indicators
are close to the obtained from the null-model ensemble, although some
deviations are observed.Comment: 13 pages, 5 figures and 5 table
Actividad hidráulica de un cemento belítico obtenido a partir de cenizas volantes tipo C: influencia del aditivo y tipo de curado
The effect of curing method and a water-reducing additive on the hydraulic activity of high lime content (ASTM type C) fly ash belite cement (FABC-2-W) is reported. A class C fly ash was subjected to hydrothermal treatment and subsequent calcination to synthesize FABC. Hydraulic activity was evaluated in the cement paste over 180 days from the physically bound water content as determined by thermogravimetric analysis and the degree of hydration, in turn found with X-ray diffraction (XRD) analysis. Mechanical strength, porosity and pore size distribution were also studied in equivalent mortar samples.En este trabajo se discute la influencia del tipo de curado y de un aditivo reductor de la demanda de agua en la actividad hidráulica de un cemento belítico de cenizas volantes de alto contenido en cal denominado (CBCV-2-A). Este cemento ha sido sintetizado por una ruta húmeda hidrotermal con posterior calcinación, empleando ceniza volante de alto contenido en cal (ASTM tipo C) como materia prima. La actividad hidráulica se ha estudiado en la pasta de cemento, durante un periodo de 180 días, por medio del contenido de agua combinada, determinada por análisis termogravimétrico, y el grado de hidratación por difracción de rayos X (DRX). La resistencia mecánica y la porosidad total y distribución de tamaño de poro se han estudiado en probetas equivalentes de morter
Lifetime suicidal-related behaviour among patients in treatment forsubstance use disorder: a cross-sectional study
Suicidal-related behaviours are an important concern in individuals who present with substance use disorders
(SUDs). The distinction among the specific characteristics of the different patients might help to improve prevention strategies. We describe and compare the sociodemographic characteristics, severity of addiction, and
psychopathology of the participants depending on the severity of their lifetime suicidal behaviour. In addition,
we examine whether the number of suicide attempts can be estimated based on the variables that differentiate
the groups. A sample of 318 men and 86 women who sought treatment for addiction were assessed. The sample
was divided into: no ideation or attempts, suicidal ideation, one suicide attempt, and two or more suicide attempts. The group with two or more suicide attempts exhibited a greater severity in the addiction profile. The
group with one suicide attempt presented a higher psychopathological symptomatology at the time of the
assessment. The severity of the Psychiatric area was related to the group with two or more attempts and to the
number of suicide attempts. The presence of any number of attempts is associated with greater severity of
addiction. Providing specific intervention strategies for SUD patients depending on their suicidal behaviours is
promising for clinical application.The first author was supported by a grant from the European UnionNext Generation EU by Ministerio de Universidades (Gobierno de
España) and Universidad del País Vasco (UPV/EHU).
The second author was supported by a grant (589/2021) from Universidad Pública de Navarra and Fundación Bancaria Caja Navarra.
Open access funding provided by Universidad Pública de Navarr
Towards low-carbon conferencing : acceptance of virtual conferencing solutions and other sustainability measures in the ALIFE community
The latest report from the Intergovernmental Panel on Climate Change (IPCC) estimated that humanity has a time window of about 12 years in order to prevent anthropogenic climate change of catastrophic magnitude. Green house gas emission from air travel, which is currently rising, is possibly one of the factors that can be most readily reduced. Within this context, we advocate for the re-design of academic conferences in order to decrease their environmental footprint. Today, virtual technologies hold the promise to substitute many forms of physical interactions and increasingly make their way into conferences to reduce the number of travelling delegates. Here, we present the results of a survey in which we gathered the opinion on this topic of academics worldwide. Results suggest there is ample room for challenging the (dangerous) business-as-usual inertia of scientific lifestyle
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