The influence of a new comb-shaped polycarboxylate-based superplasticizer (CSSP) on the hydration kinetics and transport properties of aged cement pastes has been investigated by high-resolution quasi-elastic neutron scattering (QENS) and low temperature differential scanning calorimetry (LT-DSC). A new method of analysis of QENS spectra is proposed. By applying the refined method we were able to access to four independent physical parameters including the self-diffusion coefficient of the hydration water confined in the cement paste. Mean squared displacement (MSD) of the hydrogen atom for mobile water molecules displays a dynamic crossover temperature in agreement with DSC data. The experimental results indicate that CSSP polymer added into cement paste moderates the hydration process and decreases the dynamic crossover temperature of the hydration water. 相似文献
This paper concerns with a state of bending for a linear transversely isotropic plate model based on the Mindlin assumption on the displacement. By using appropriate families of line-integral measures, we are able to establish results about the spatial behaviour of transient and steady-state solutions. All the results are obtained under relaxed hypotheses on the positive definiteness of the elasticity tensor. 相似文献
Apixaban, a direct oral anticoagulant drug (DOAC), typically does not require routine therapeutic drug monitoring (TDM), yet recent guidelines propose its use in specific clinical scenarios. While various antifactor Xa (anti-FXa) chromogenic assays serve as useful proxies for measuring plasma exposure to apixaban in emergencies, they lack specificity compared with chromatographic methods. This research project is intended to the development and validation of a standardized protocol of liquid chromatography–tandem mass spectrometry (LC–MS/MS) in conformity with the ICH guidelines M10 for the measurement of apixaban in both plasma and dried plasma spots (DPSs). Samples preparation included protein precipitation after the addition of a deuterated internal standard (IS), and the chromatographic separation was carried out on a Thermo Scientific™ Accucore™ Polar Premium column (50 mm × 2.1 mm, i.d. 2.6 m). The newly developed LC–MS/MS method for apixaban mesurement from both plasma and DPS resulted linear over a wide concentration range (31.25–500 ng/mL), accurate, and reproducible without matrix effects, allowing for specific and rapid quantification. Stability was assessed on quality controls and a real sample, allowing the setting up of a robust TDM protocol that was applied to five anonymized plasma samples obtained from adult patients undergoing apixaban treatment at steady-state. In conclusion our novel LC–MS/MS method is adequate for accurate apixaban quantitation from both plasma and DPS matrixes, and may thus facilitate the guidelines suggested implementation of apixaban TDM, even in peripheral hospitals through shipment of DPS at reference laboratories. 相似文献
Astrocytes greatly participate to inflammatory and neurotoxic reactions occurring in neurodegenerative diseases and are valuable pharmacological targets to support neuroprotection. Here we used human astrocytes generated from reprogrammed fibroblasts as a cellular model to study the effect of the compound Laquinimod and its active metabolite de-Laquinimod on astrocyte functions and the astrocyte–neuron interaction. We show that human iAstrocytes expressed the receptor for the inflammatory mediator IL1 and responded to it via nuclear translocation of NFκB, an event that did not occur if cells were treated with Laquinimod, indicating a direct anti-inflammatory activity of the drug on the human astrocyte. Similarly, while exposure to IL1 downregulated glial glutamate transporters GLAST and GLT1, treatment with Laquinimod supported maintenance of physiological levels of these proteins despite the inflammatory milieu. Laquinimod also induced nuclear translocation of the aryl hydrocarbon receptor (AHR), suggesting that drug action was mediated by activation of the AHR pathway. However, the drug was effective despite AHR inhibition via CH223191, indicating that AHR signaling in the astrocyte is dispensable for drug responses. Finally, in vitro experiments with rat spinal neurons showed that laquinimod did not exert neuroprotection directly on the neuron but dampened astrocyte-induced neurodegeneration. Our findings indicate that fibroblast-derived human astrocytes represent a suitable model to study astrocyte–neuron crosstalk and demonstrate indirect, partial neuroprotective efficacy for laquinimod. 相似文献
Two new families of N,O-nucleoside analogues containing the anthracene moiety introduced through the nitrosocarbonyl ene reaction with allylic alcohols were prepared. The core structure is an isoxazolidine heterocycle that introduces either atom either a phenyl ring or dimethyl moiety at the C3 carbon. Different heterobases were inserted at the position 5 of the heterocyclic ring. One of the synthesized compounds demonstrated a good capacity to induce cell death and an appreciable nuclear fragmentation was evidenced in treated cells. 相似文献
The electrocatalytic conversion of 5-hydroxymethylfurfural (HMF), a biomass platform molecule, to 2,5-bis(hydroxymethyl)furan (BHMF), a polymer precursor, is a fully sustainable route that operates at room temperature and pressure, using water as source of hydrogen, and avoids high H2 pressures. In this work, we investigate the use of 3D electrocatalysts, made by Ag0 electrodeposited on Cu open-cell foams (Ag/Cu), to improve the efficiency in the electrochemical conversion of HMF to BHMF in basic media at different HMF concentrations. For comparison purposes, Ag and Cu bulk foams as well as Ag, Cu and Ag/Cu foil counterparts are investigated. For diluted 0.02 M HMF solutions, BHMF is selectively produced at high HMF conversion and FE over Ag/Cu foams. The large surface area of 3D Ag/Cu foams, compared to their 2D counterparts, does not affect selectivity, but increases the rate of conversion and in turn the productivity. However, it would appear that the increase in the surface area is not enough to increase the efficiency in the conversion of more concentrated HMF electrolytes (0.05–0.50 M). The productivity of Ag/Cu is modified with electrocatalytic cycles. 相似文献
Invited for this month's cover picture is the group of Dr. Francesca Soavi (Laboratory of Electrochemistry of Materials for Energetics, Department of Chemistry “Giacomo Ciamician”, University of Bologna). The cover picture shows a microbial fuel cell connected in parallel with a supercapacitor. Read the full text of the Article at 10.1002/celc.201901876 . 相似文献
The rise of semiconductor‐based pump sources such as InxGa1‐xN‐laser diodes or frequency‐doubled optically pumped semiconductor lasers with emission wavelengths in the blue encourages a revisitation of the rare‐earth ions Pr3+, Sm3+, Tb3+, Dy3+, Ho3+ and Er3+ with respect to their properties as active ions in crystalline solid‐state laser materials with direct emission in the visible spectral range. Nowadays, some of these blue‐pumped visible lasers compete with Nd3+‐lasers in terms of efficiency and direct lasing at various colors from the cyan‐blue to the deep red can be addressed in very simple and compact laser setups. This paper highlights the spectroscopic properties of suitable rare‐earth ions for visible lasing and reviews the latest progress in the field of blue‐pumped visible rare‐earth doped solid‐state lasers.
The rapid development of on-surface synthesis provides a unique approach toward the formation of carbon-based nanostructures with designed properties. Herein, we present the on-surface formation of CN-substituted phenylene vinylene chains on the Au(111) surface, thermally induced by annealing the substrate stepwise at temperatures between 220 °C and 240 °C. The reaction is investigated by scanning tunneling microscopy and density functional theory. Supported by the calculated reaction pathway, we assign the observed chain formation to a Knoevenagel condensation between an aldehyde and a methylene nitrile substituent. 相似文献
