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Global industry relies on a linear approach for economic growth. One step towards transformation is the implementation of a circular economy and the reclamation of anthropogenic deposits. This study examines two filter dusts, one German and one Argentinian, from the production of calcined clays, representing such deposits. Investigations and comparisons of untreated and calcined filter dust and the industrial base product pave the way for using waste product filter dust as supplementary cementitious material (SCM). In the future, some twenty thousand tons of contemporary waste could potentially be used annually as SCM. The results confirm the suitability of one material as a full-fledged SCM without further treatment and a measured pozzolanic reactivity on par with fly ash. Sample materials were classified into two groups: one was found to be a reactive pozzolanic material; the other was characterized as filler material with minor pozzolanic reactivity. Additionally, important insights into the physical properties of oven dust and heat-treated oven dust were obtained. For both material groups, an inversely proportional relationship with rising calcination temperatures was found for the specific surface area and water demand. The impact of the calcination temperature on both the particle size distribution and the potential to optimize the reactivity performance is presented. [ABSTRACT FROM AUTHOR]

With an output of more than two million tons of alumina per year, Venezuela is an important producer. As observed, this mining extraction activity generates a large number of by-products poorly valorized for many reasons (economic, technical, and due to environmental standards and regulations) Venezuela production generates wastes (more than 15 million of m3) called red muds, which are dumped in old lagoons near the Orinoco river or stored. This sludge has a high alkalinity (pH between 10 and 13) and a chemical composition containing some heavy metals (40 ppm Cr, 107 ppm La, 178 ppm Ce) that means it is considered environmentally problematic waste. However, their mineralogical, textural and structural characteristics make them adsorption materials. So, the aim of the study presented here was to investigate the sorption properties of these residues in the case of treatment of water from acid mine drainage. In fact, with an important reactive surface, their capacities to trap by adsorption trace elements such as cadmium, lead or zinc has been studied. Batch sorption tests revealed significant retention of contaminants such as Pb, Zn and As. These retention processes were interpreted using the Langmuir isotherm model. The promising first results indicate that the red mud named Venezuelan bauxite residue (VBR) reveals its great potential as a sorbent of inorganic pollutants. The sorption process is chemically dependent and efficient for certain pH and IS ranges. In addition, the material showed a strong affinity for the adsorption of arsenate (As5+). This was observed during post adsorption chemical speciation experiments, through the very high affinity of this element for the least mobile fractions, including oxyhydroxides mobile fractions, including Fe oxyhydroxides (amorphous). Nevertheless, these mining by-products could be considered as valuable absorbent materials. Despite this promising results, further studies are required to evaluate their potential in different conditions (dynamic tests, pH, IS, inorganic and organic contaminants, concentration and time effect). [ABSTRACT FROM AUTHOR]

A subpopulation of astrocytes on the brain's surface, known as subpial astrocytes, constitutes the "glia limitans superficialis" (GLS), which is an interface between the brain parenchyma and the cerebrospinal fluid (CSF) in the subpial space. Changes in connexin-43 (Cx43) and aquaporin-4 (AQP4) proteins in subpial astrocytes were examined in the medial prefrontal cortex at postoperative day 1, 3, 7, 14, and 21 after sham operation and sciatic nerve compression (SNC). In addition, we tested the altered uptake of TRITC-conjugated 3 kDa dextran by reactive subpial astrocytes. Cellular immunofluorescence (IF) detection and image analysis were used to examine changes in Cx43 and AQP4 protein levels, as well as TRITC-conjugated 3 kDa dextran, in subpial astrocytes. The intensity of Cx43-IF was significantly increased, but AQP4-IF decreased in subpial astrocytes of sham- and SNC-operated rats during all survival periods compared to naïve controls. Similarly, the uptake of 3 kDa dextran in the GLS was reduced following both sham and SNC operations. The results suggest that both sciatic nerve injury and peripheral tissue injury alone can induce changes in subpial astrocytes related to the spread of their reactivity across the cortical surface mediated by increased amounts of gap junctions. At the same time, water transport and solute uptake were impaired in subpial astrocytes. [ABSTRACT FROM AUTHOR]

This study explored the potential of ultrafine kaolin as a geopolymer raw material, focusing on the reactivity of calcined kaolin products and its influencing factors. Through a series of analytical techniques, including thickening experiments, particle size analysis, SEM, XRD, and FT-IR, the effects of calcination temperature, time, and Si-Al ratio were evaluated. The results indicated that calcination temperature significantly impacts reactivity, with optimal conditions found between 600 °C and 800 °C, yielding metakaolin with thickening times of 12 to 43 min. Temperatures above 900 °C led to the formation of low-reactivity phases like mullite. The Si-Al ratio also influenced thickening time, with durations varying from 97 min at 0.85 to 43 min at 0.9 and increasing to 157 min at 0.95. Calcination time had the smallest effect, with thickening times ranging from 10 to 25 min over 4 to 8 h. Additionally, calcination altered particle size, initially expanding due to thermal expansion and later shrinking due to lattice distortion above 700 °C. By adjusting these parameters, the reactivity of calcined kaolin could be tailored to suit specific needs. This research provides a theoretical foundation for metakaolin's application in construction materials and offers novel insights into geopolymer preparation. [ABSTRACT FROM AUTHOR]

The reactivity effect of metacognitive judgments on first-order task performance has received increased research attention. Previous studies showed that soliciting retrospective confidence ratings (CRs) reactively enhances task performance itself, such as performance in decision making and reasoning tasks, especially for those with high self-confidence. It remains unknown whether CRs can improve students' academic assessment performance in real educational settings. The current study recruited 795 fourth-grade elementary school children to explore if making CRs reactively affects students' academic assessment performance in two main subjects (i.e., Chinese Language and Mathematics). The data were collected across six waves with half-year intervals. From Wave 2, children either provided (CR group) or did not provide CRs (no-CR group) when completing standardized academic assessments. The results showed Bayesian evidence supporting the claim that making CRs does not influence children's academic assessment performance (both the average performance across waves 2–6 and the performance in each wave) in both subjects. Furthermore, children's self-confidence did not moderate the reactive influence of CRs. The results from multilevel regression analyses re-confirmed the above conclusions. Possible explanations for the absence of the reactivity effect of CRs on children's academic assessment performance are discussed. [ABSTRACT FROM AUTHOR]

Construction spoil (CS), a prevalent type of construction and demolition waste, is characterized by high production volumes and substantial stockpiles. It contaminates water, soil, and air, and it can also trigger natural disasters such as landslides and debris flows. With the advent of alkali activation technology, utilizing CS as a precursor for alkali-activated materials (AAMs) or supplementary cementitious materials (SCMs) presents a novel approach for managing this waste. Currently, the low reactivity of CS remains a significant constraint to its high-value-added resource utilization in the field of construction materials. Researchers have attempted various methods to enhance its reactivity, including grinding, calcination, and the addition of fluxing agents. However, there is no consensus on the optimal calcination temperature and alkali concentration, which significantly limits the large-scale application of CS. This study investigates the effects of the calcination temperature and alkali concentration on the mechanical properties of CS–cement mortar specimens and the ion dissolution performance of CS in alkali solutions. Mortar strength tests and ICP ion dissolution tests are conducted to quantitatively assess the reactivity of CS. The results indicate that, compared to uncalcined CS, the ion dissolution performance of calcined CS is significantly enhanced. The dissolution amounts of active aluminum, silicon, and calcium are increased by up to 420.06%, 195.81%, and 256.00%, respectively. The optimal calcination temperature for CS is determined to be 750 °C, and the most suitable alkali concentration is found to be 6 M. Furthermore, since the Al O bond is weaker and more easily broken than the Si O bond, the dissolution amount and release rate of active aluminum components in calcined CS are substantially higher than those of active silicon components. This finding indicates significant limitations in using CS solely as a precursor, emphasizing that an adequate supply of silicon and calcium sources is essential when preparing CS-dominated AAMs. [ABSTRACT FROM AUTHOR]

Willow is a promising biomass resource for addressing the challenges of securing stable domestic biomass fuels in Japan and utilising abandoned agricultural land. Among the willow species, Salix pet-susu Kimura KKD (known as ezonokinu willow, EW) stands out for its growth, high production, storage stability, production stability, and business stability. Previous studies have investigated fuel characterisation through gasification (co-gasification) of various biomass mixtures to enhance feedstock flexibility for gasifier commercialisation. However, the synergistic effects of co-gasification using fuels containing EW blended with Japanese cedar, a commonly planted forest species in Japan, remain unexplored. Therefore, this study explored CO2 co-gasification with different blend ratios of EW/cedar blended char and evaluated the fuel characteristics for each blend ratio to elucidate the synergistic effects. The prepared char samples were utilised in the CO2 gasification test with TG-DTA as the analyser. The results suggest that in the initial stages of the willow/cedar blended char co-gasification reaction, pore size and specific surface area significantly influence the reaction rate. Subsequent stages of the reaction are influenced by the promoting and inhibiting effects of inorganic components, which impact co-gasification. The synergy factor results for the willow/cedar blended char co-gasification suggest a reaction pathway. [ABSTRACT FROM AUTHOR]

Metal complexes of benzotriazole-type ligands continue to attract the intense interest of many inorganic chemistry groups around the world for a variety of reasons, including their aesthetically beautiful structures, physical properties and applications. 1-methylbenzotriazole (Mebta) is the N-substituted archetype of the parent 1H-benzotriazole. The first attempt to build a "periodic table" of Mebta, which includes its complexes with several metal ions, is described in this work. This, at first glance, trivial ligand has led to interesting results in terms of the chemistry, structures and properties of its metal complexes. This work reviews the to-date published coordination chemistry of Mebta with Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), Cu(II), Zn(II), Pd(II), Au(I) and {UVIO2}2+, with emphasis on their preparations, reactivity, structures and properties. Unpublished results from our group comprising other Co(II), Ni(II), Cu(II) and Zn(II) complexes, as well as Cd(II), Hg(II), Ag(I), In(III) and Sn(IV) ones are briefly reported. Mebta can also provide access to 1D and 3D heterometallic thiocyanato-bridged Co(II)/Hg(II) and Ni(II)/Hg(II) compounds. In almost all cases, Mebta behaves as a monodentate ligand with the nitrogen of position 3 of the azole ring as the donor atom. However, there are two copper complexes in which this molecule adopts a bidentate bridging coordination behavior. Our efforts to complete the "periodic table" of Mebta are continued. [ABSTRACT FROM AUTHOR]

The designed MYRRHA reactor, in its subcritical version, will be equipped with a set of detectors monitoring its condition by measuring the current value of negative reactivity, which is a crucial parameter for its safe operation. In subcritical systems, accurate and precise measurement of negative reactivity is disturbed by the so-called spatial effect, i.e., the response of detectors depends on their placement in the reactor core. This paper focuses on the Monte Carlo simulations of reactivity measurements using the area method for natU, 238U, 241Am, 239Pu, and 232Th detectors. The simulations were performed in six positions with increasing distance from the center of the core and at three axial levels. The obtained results allow for selecting optimum locations for detectors and detector nuclides in terms of the accuracy of reactivity measurement and illustrate the dependence of the reactivity on the distance. Additionally, the possibility of using 103Rh in self-powered neutron detectors was investigated. The influence of spatial effect in calculations using the area method was directly indicated in the MYRRHA reactor core for chosen isotopes and in-core positions. The results closest to true values were obtained for the second fuel assembly for 239Pu, and the third fuel assembly for natU, 238U, 232Th, and 241Am; thus, these nuclides and positions should be preferred when selecting detectors for MYRRHA. [ABSTRACT FROM AUTHOR]

In this research, the properties and cementitious performance of thermally activated cement pastes (referred to as DCPs) are investigated. Hydrated pastes prepared from Portland cement and slag blended cement were subjected to different thermal treatments: 350 °C for 2 h, 550 °C for 2 h, 550 °C for 24 h and 750 °C for 2 h. The properties and the reactivity as SCM of the DCPs were characterised as well as their effect on the mechanical performance and hydration of new blended cements incorporating the DCPs as supplementary cementitious materials (SCMs). It was observed that the temperature and duration of the thermal treatment increased the grindability and BET specific surface area of the DCP, as well as the formation of C2S phases and the reactivity as SCM. In contrast, the mechanical strength results for the blended cements indicated that thermal treatment at 350 °C for 2 h provided better performance. The hydration study results showed that highly reactive DCP interfered with the early hydration of the main clinker phases in Portland cement, leading to early setting and slow strength gain. The effect on blended cement hydration was most marked for binary Portland cement–DCP blends. In contrast, in the case of ternary slag cement–DCP blends the use of reactive DCP as SCM enabled to significantly increase early age strength. [ABSTRACT FROM AUTHOR]

High-performance catalysts for the oxygen reduction and hydrogen evolution reactions (ORR and HER, respectively) are highly sought-after, particularly with the commitment of numerous agencies to the removal of conventional gas vehicles in the next few decades. Surprisingly little focus has been placed on the development of magnetic models to describe these systems. The current work will review the current understanding of surface heterogeneous catalysis across select magnetic surfaces, with attention focused on studies involving extended surfaces, which inherently are more accessible to fundamental analysis than the more applied nanoparticle systems. However, even the most up-to-date magnetic variants of this theory have focused on the tight binding limit of the d-band model. In this limit, the reactivity of the surface is governed by the position of the center of the d-band, and the model does not account for the higher moments of the d-band, such as the width, asymmetry, and modality. A summary of the theory supporting this analysis will be presented, along with a summary of the current literature on this level of analysis. The review will then conclude with a discussion of suggested directions for future investigations. [ABSTRACT FROM AUTHOR]

Xanthates have long been described as poor RAFT/MADIX agents for styrene polymerization. Through the determination of chain transfer constants to xanthates, this work demonstrated beneficial capto-dative substituent effects for the leaving group of a new series of α-amido trifluoromethyl xanthates, with the best effect observed with trifluoroacetyl group. The previously observed Z-group activation with a O-trifluoroethyl group compared to the O-ethyl counterpart was quantitatively established with Cex = 2.7 (3–4 fold increase) using the SEC peak resolution method. This study further confirmed the advantageous incorporation of trifluoromethyl substituents to activate xanthates in radical chain transfer processes and contributed to identify the most reactive xanthate reported to date for RAFT/MADIX polymerization of styrene. [ABSTRACT FROM AUTHOR]

Today, neurodegenerative disorders like Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) affect millions of people worldwide, and as the average human lifespan increases, similarly grows the number of patients. For many decades, cognitive and motoric decline has been explained by the very apparent deterioration of neurons in various regions of the brain and spinal cord. However, more recent studies show that disease progression is greatly influenced by the vast population of glial cells. Astrocytes are traditionally considered star-shaped cells on which neurons rely heavily for their optimal homeostasis and survival. Increasing amounts of evidence depict how astrocytes lose their supportive functions while simultaneously gaining toxic properties during neurodegeneration. Many of these changes are similar across various neurodegenerative diseases, and in this review, we highlight these commonalities. We discuss how astrocyte dysfunction drives neuronal demise across a wide range of neurodegenerative diseases, but rather than categorizing based on disease, we aim to provide an overview based on currently known mechanisms. As such, this review delivers a different perspective on the disease causes of neurodegeneration in the hope to encourage further cross-disease studies into shared disease mechanisms, which might ultimately disclose potentially common therapeutic entry points across a wide panel of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) and coupled cluster theory (CCSD(T)) calculations are performed to investigate the geometric and electronic structures and chemical bonding of a series of Cu-doped zinc oxide clusters: CunZn3O3 (n = 1–4). The structural evolution of CunZn3O3 (n = 1–4) clusters may reveal the aggregation behavior of Cu atoms on the Zn3O3 cluster. The planar seven-membered ring of the CuZn3O3 cluster plays an important role in the structural evolution; that is, the Cu atom, Cu dimer (Cu2) and Cu trimer (Cu3) anchor on the CuZn3O3 cluster. Additionally, it is found that CunZn3O3 clusters become more stable as the Cu content (n) increases. Bader charge analysis points out that with the doping of Cu atoms, the reducibility of Cu aggregation (Cun−1) on the CuZn3O3 cluster increases. Combined with the d-band centers and the surface electrostatic potential (ESP), the reactivity and the possible reaction sites of CunZn3O3 (n = 1–4) clusters are also illustrated. [ABSTRACT FROM AUTHOR]

Calcined mixed clays are one of the most promising alternative supplementary cementitious materials. However, their standardized use is difficult due to the wide range of compositions of the raw materials. The reactivity potential of different clays can hardly be estimated on the basis of simple characteristics so far. This review aims to identify and compile the factors that determine reactivity. At first, an overview of the methods to evaluate reactivity is presented in order to provide a definition of this term. Subsequently, the reactivity-determining factors are compiled and subdivided into the characteristics of the raw material (chemical and mineralogical composition), the parameters of calcination (furnace type, temperature, grain size, retention time, and cooling), and the characteristics of the calcined material (physical properties and amorphous phase). Interrelations are discussed qualitatively. In the second step, a quantitative literature analysis was conducted to quantify correlations between the different factors and reactivity. However, since the characterization methods in the literature are very different, the data can hardly be analyzed quantitatively. Consequently, this paper points out what information is needed to conduct profound, comparable studies to evaluate the reactivity potential of clays. [ABSTRACT FROM AUTHOR]

Graphene is thought to be a promising material for many applications. However, pristine graphene is not suitable for most electrochemical devices, where defect engineering is crucial for its performance. We demonstrate how the boron doping of graphene can alter its reactivity, electrical conductivity and potential application for sodium and aluminum storage, with an emphasis on novel metal-ion batteries. Using Density Functional Theory calculations, we investigate both the influence of boron concentration and the oxidation of the material on the mentioned properties. It is demonstrated that the presence of boron in graphene increases its reactivity towards atomic hydrogen and oxygen-containing species; in other words, it makes B-doped graphene more prone to oxidation. Additionally, the presence of these surface functional groups significantly alters the type and strength of the interaction of Na and Al with the given materials. Boron-doping and the oxidation of graphene is found to increase the Na storage capacity of graphene by a factor of up to four, and the calculated sodiation potentials indicate the possibility of using these materials as electrode materials in high-voltage Na-ion batteries. [ABSTRACT FROM AUTHOR]

Petroselinic fatty acid (PeFA) is considered a rare fatty acid and one of the most important fatty acids in the Apiaceae family. Its content varies depending on plant species, geographical origin, extraction method, ripeness, etc. Indeed, reported levels of petroselinic fatty acid range from 10.4 to 75.6% (in anise seed oil), 1 to 81.9% (in coriander seed oil), 28.5 to 57.6% (in caraway seed oil), 49.4 to 75.6% (in celery seed oil), 41.3 to 61.8% (in caraway seed oil), 79.9 to 87.2% (in dill seed oil), 43.1 to 81.9% (in fennel seed oil), and 35 to 75.1% (parsley seed oil). In this review, we also show current knowledge about genes encoding biosynthesis, from the desaturation of 16:0-ACP to petroselinic acid stored in triacylglycerol in the seeds. Furthermore, petroselinic acid is not related to the synthesis of ABA. PeFA was successfully isolated from Apiaceae family plant seeds in order to study their reactivity and biological activities. Several investigations showed that this fatty acid has a wide range of biological potentials, including antidiabetic, antibacterial, and antifungal activities. In cosmetics, PeFA alone or in association with other active compounds has interesting applications as an anti-inflammatory agent for the treatment of skin, hair, and nail disorders. [ABSTRACT FROM AUTHOR]

Fatty acids (FA) and their derivatives with long alkyl chain structures are good candidates for wood esterification to confer thermoplastic properties to wood. Nevertheless, they do not react easily with hydroxyl groups of wood. In this study, we investigated the reactivity of wood with various fatty acids of different chain lengths using trifluoroacetic anhydride (TFAA) as the impelling agent in various reaction conditions. Generally, the esterification of fatty acids without solvents resulted in higher Weight Percentage Gain (WPG) and ester content than the reaction in the presence of CH2Cl2. The esterification reaction could be performed effectively at room temperature, though an increased reaction temperature provoked degradation of the esterified wood. WPG of 67% was obtained for the C3 and 253% for the C16 alkyl chain analogs, respectively. Nevertheless, the ester content was fairly uniform, with values between 10.60 and 11.81 mmol ester/gram of wood for all chain lengths. A higher quantity of reagent led to higher ester content, which tended to stabilize after a ratio of 1:4 wood and TFAA/FA. The esterification reaction was performed rapidly, with an ester content between 7.65 and 9.94 mmol ester/gram of wood being achieved only after 15 min of reaction. Fourier transform infrared spectroscopy (FTIR) analysis was performed to confirm the drastic chemical changes of wood before and after esterification. Morphological observation by scanning electron microscope (SEM), softening measurement by thermomechanical analysis (TMA), and contact angle measurements demonstrated the possibility of esterified spruce wood being applied as a new bioplastic. [ABSTRACT FROM AUTHOR]

Judgments of learning (JOL) are one of the most commonly used measures of metamemory. There is mixed evidence that eliciting JOLs while participants are studying word pairs influences their subsequent recall, a phenomenon known as reactivity. The majority of studies have found that positive reactivity occurs when word pairs are related. This finding suggests that when the final test is sensitive to the cues used to make a JOL (e.g., pair relatedness), a benefit to recall is observed. Here, in three experiments, JOL reactivity is examined in the presence of a salient, yet non-diagnostic cue—font size. The results show that when study time is limited and font size is made salient, eliciting JOLs impairs future recall. It is argued that JOLs prompt participants to evaluate salient cues in the learning environment to evaluate whether they will affect future recall. This increased processing of salient cues can impair recall if it comes at the expense of processing less salient but more informative cues. These findings suggest that the relevance to the test of the cues processed when JOLs are performed determines the direction of reactivity effects, with both positive and negative reactivity being possible depending on how diagnostic the salient metacognitive cues are for recall. [ABSTRACT FROM AUTHOR]

The durability of concrete requires a dense microstructure which can be achieved by using self-compacting concrete (SCC). Both calcined clay (CC) and rice husk ash (RHA) are promising supplementary cementitious materials (SCMs) that can partially replace cement, but their use in SCC is critical due to their higher water demand (WD) and specific surface area (SSA) compared to cement. The effect of partial substitution of cement at 20 vol-% with binary and ternary blends of CC and RHA on flowability retention and durability of SCC was investigated. The empirical method of SCC design was adopted considering the physical properties of both CC and RHA. The deformability of the SCC was evaluated using the slump flow and J-ring tests. The T500 time and the V-funnel test were used to assess the viscosity of the SCC. The flowability retention was monitored by the plunger method, and flow resistance was determined based on the rheological measurements of SCC. The evolution of the hydrate phases of the binder in SCC was determined by thermogravimetric analysis, while the durability was evaluated by a rapid chloride migration test. Cement partial replacement with 20 vol-% CC has no significant effect on fresh SCC, flowability retention, compressive strength and durability properties. On the other hand, 20 vol-% RHA requires a higher dosage of SP to achieve self-compactability and increase the viscosity of SCC. Its flowability retention is only up to 30 min after mixing and exhibited higher flow resistance. It consumes more calcium hydroxide (CH) and improves the compressive strength and chloride resistance of SCC. The ternary blending with CC and RHA yielded better fresh SCC properties compared to the binary blend with RHA, while an improved chloride penetration resistance could be achieved compared to the binary CC blend. [ABSTRACT FROM AUTHOR]

Functionalization of endohedral metallofullerenes (EMFs) plays an important role in exploring the reactivity of EMFs and stabilizing missing EMFs, thus conferring tunable properties and turning EMFs into applicable materials. In this review, we present exhaustive progress on the functionalization of EMFs since 2019. Classic functionalization reactions include Prato reactions, Bingel–Hirsch reactions, radical addition reactions, carbene addition reactions, and so on are summarized. And new complicated multi-component reactions and other creative reactions are presented as well. We also discuss the structural features of derivatives of EMFs and the corresponding reaction mechanisms to understand the reactivity and regioselectivity of EMFs. In the end, we make conclusions and put forward an outlook on the prospect of the functionalization of EMFs. [ABSTRACT FROM AUTHOR]

The ladder phenyl/vinyl polysilsesquioxane (PhVPOSS) was used to improve the flame-retardancy performances of ethylene-vinyl acetate copolymer (EVA)/aluminum hydroxide (ATH) composites due to the reactivity of its vinyl groups. FTIR, XPS, 1H NMR, and SEM-EDS data demonstrated the PhVPOSS grafting onto EVA molecular chains. The PhVPOSS improved the thermal stability of EVA/ATH composites, as shown by the thermogravimetric analysis (TGA). Furthermore, with the cone calorimeter (CONE) experiments, EVA/ATH/PhVPOSS showed better fire safety than the EVA/ATH composites, with the PHRR, PSPR, and PCOP reduced by 7.89%, 57.4%, and 90.9%, respectively. The mechanism investigations of flame retardancy revealed that the charring behaviors of the EVA/ATH/PhVPOSS composites were improved by the formation of Si-C bonds and Si-O bonds, and a more compact and denser char layer can contribute more to the barrier effect. [ABSTRACT FROM AUTHOR]

Resolvin E1 is a metabolite of eicosapentaenoic acid (EPA) which is one of the omega-3 polyunsaturated fatty acids (omega-3 PUFAs). The antiplatelet properties of omega-3 PUFAs are well known, but the effect of resolvin E1 on platelets via the collagen receptors is extremely poorly reported. We investigated the effect of resolvin E1 on collagen-induced platelet aggregation, activation, and reactivity, and also platelet membrane fluidity. The ultimate and statistically significant results showed that resolvin E1 may inhibit platelet reactivity due to the reduction of collagen-induced platelet aggregation in platelet-rich plasma and isolated platelets, but not in whole blood. Also, resolvin E1 significantly reduced P-selectin exposure on collagen-stimulated platelets. Moreover, we demonstrated that resolvin E1 can maintain platelet membrane structure (without increasing membrane fluidity). The association between platelet reactivity and membrane fluidity, including resolvin E1 and collagen receptors requires further research. However, the goal of this study was to shed light on the molecular mechanisms behind the anti-aggregative effects of resolvin E1 on platelets, which are still not fully clarified. We also indicate an innovative research direction focused on further analysis and then use of omega-3 PUFAs metabolites as antiplatelet compounds for future applications in the treatment and prevention of cardiovascular diseases. [ABSTRACT FROM AUTHOR]

The search for alternative materials to replace ordinary Portland cement has been the object of work that enhances the investigation of the use of pozzolanic materials and the reduction of the carbon footprint with supplementary cementitious materials. However, not all materials are available to meet the large-scale demand for cement replacement. A relevant exception is the calcined clay, a material found worldwide that, when subjected to appropriate heat treatment, presents pozzolanic reactivity and can be used as a supplementary material to cement. This review presents, through a systematic search, methods for measuring the pozzolanic reactivity of calcined clays, namely, direct, indirect, qualitative, quantitative, chemical and physical methods such as electrical conductivity (Lùxan), the force activity index, the modified Chapelle, R3, Frattini test, thermal analysis, X-ray diffraction and X-ray fluorescence spectrometry. The most usual methods to assess the pozzolanic reactivity of calcined clays were exposed and analyzed. It should be pointed out that there is greater use of the Frattini and modified Chapelle methods as well as the analysis of the mechanical strength behavior of the material in cementitious matrices. X-ray diffraction and thermal analysis were exposed as the most used correlation methods but it was also concluded that different tests are needed to generate accurate results. [ABSTRACT FROM AUTHOR]

Wheat straw, a typical agricultural solid waste, was employed to clarify the effects of torrefaction on the structural features and combustion reactivity of biomass. Two typical torrefaction temperatures (543 K and 573 K), four atmospheres (argon, 6 vol.% O2, dry flue gas and raw flue gas) were selected. The elemental distribution, compositional variation, surface physicochemical structure and combustion reactivity of each sample were identified using elemental analysis, XPS, N2 adsorption, TGA and FOW methods. Oxidative torrefaction tended to optimize the fuel quality of biomass effectively, and the enhancement of torrefaction severity improved the fuel quality of wheat straw. The O2, CO2 and H2O in flue gas could synergistically enhance the desorption of hydrophilic structures during oxidative torrefaction process, especially at high temperatures. Meanwhile, the variations in microstructure of wheat straw promoted the conversion of N-A into edge nitrogen structures (N-5 and N-6), especially N-5, which is a precursor of HCN. Additionally, mild surface oxidation tended to promote the generation of some new oxygen-containing functionalities with high reactivity on the surface of wheat straw particles after undergoing oxidative torrefaction pretreatment. Due to the removal of hemicellulose and cellulose from wheat straw particles and the generation of new functional groups on the particle surfaces, the ignition temperature of each torrefied sample expressed an increasing tendency, while the Ea clearly decreased. According to the results obtained from this research, it could be concluded that torrefaction conducted in a raw flue gas atmosphere at 573 K would improve the fuel quality and reactivity of wheat straw most significantly. [ABSTRACT FROM AUTHOR]

The carbon dioxide gasification performance of low-quality lignite-agroindustrial/forest waste blends was investigated in terms of reactivity, conversion, cold gas efficiency, product gas composition and heating value. The experiments were conducted in a fixed bed unit and a thermal analysis mass spectrometer system. Raw materials, chars, liquids and gases were quantitatively analyzed and their energy content was determined. Synergetic effects and the role of minerals were examined, the latter through chemical and fusibility analyses of the ashes. Ahlada lignite (AL) was of low quality, with a calorific value of 8.9 MJ/kg. The biomass materials, ginning cotton waste (GCW) and pine needles (PN) had calorific values 16.6 MJ/kg and 20.1 MJ/kg, respectively. The slagging/fouling propensity of AL ash was low, whereas that of biomass wastes was medium to high. Thermal treatment of the samples and their blends prior to gasification produced upgraded fuels. A Boudourd reaction occurred above 750 °C. Gasification reactivity followed the order: GCW > PN > AL. AL/PN mixtures presented additivity effects; however, AL/GCW mixtures presented synergy effects. When the lignite was blended with the biochars studied, its conversion increased from 90% to 94.5% and its cold gas efficiency from 31.8% to 35%. Generated gas attained a heating value of about 12 MJ/m3. [ABSTRACT FROM AUTHOR]

Neuroglial cells, and especially astrocytes, constitute the most varied group of central nervous system (CNS) cells, displaying substantial diversity and plasticity during development and in disease states. The morphological changes exhibited by astrocytes during the acute and chronic stages following CNS injury can be characterized more precisely as a dynamic continuum of astrocytic reactivity. Different subpopulations of reactive astrocytes may be ascribed to stages of degenerative progression through their direct pathogenic influence upon neurons, neuroglia, the blood-brain barrier, and infiltrating immune cells. Multiple sclerosis (MS) constitutes an autoimmune demyelinating disease of the CNS. Despite the previously held notion that reactive astrocytes purely form the structured glial scar in MS plaques, their continued multifaceted participation in neuroinflammatory outcomes and oligodendrocyte and neuronal function during chronicity, suggest that they may be an integral cell type that can govern the pathophysiology of MS. From a therapeutic-oriented perspective, astrocytes could serve as key players to limit MS progression, once the integral astrocyte–MS relationship is accurately identified. This review aims toward delineating the current knowledge, which is mainly focused on immunomodulatory therapies of the relapsing–remitting form, while shedding light on uncharted approaches of astrocyte-specific therapies that could constitute novel, innovative applications once the role of specific subgroups in disease pathogenesis is clarified. [ABSTRACT FROM AUTHOR]

The modifications of the electronic properties on carbon-doped boron nitride nanoribbons (BNNRs) as a response to the adsorption of different nitro species were investigated in the framework of the density functional theory within the generalized gradient approximation. Calculations were performed using the SIESTA code. We found that the main response involved tuning the original magnetic behavior to a non-magnetic system when the molecule was chemisorbed on the carbon-doped BNNR. It was also revealed that some species could be dissociated through the adsorption process. Furthermore, the nitro species preferred to interact over nanosurfaces where dopants substituted the B sublattice of the carbon-doped BNNRs. Most importantly, the switch on the magnetic behavior offers the opportunity to apply these systems to fit novel technological applications. [ABSTRACT FROM AUTHOR]

The structural and energetic properties of small silver clusters Ag n with n = 2–100 atoms are reported. For n = 2–100 the embedded atom model for the calculation of the total energy of a given structure in combination with the basin-hopping search strategy for an unbiased structure optimization has been used to identify the energies and structures of the three energetically lowest-lying isomers. These optimized structures for n = 2–11 were subsequently studied further through density-functional-theory calculations. These calculations provide additional information on the electronic properties of the clusters that is lacking in the embedded-atom calculations. Thereby, also quantities related to the catalytic performance of the clusters are studied. The calculated properties in comparison to other available theoretical and experimental data show a good agreement. Previously unidentified magic (i.e., particularly stable) clusters have been found for n > 80 . In order to obtain a more detailed understanding of the structural properties of the clusters, various descriptors are used. Thereby, the silver clusters are compared to other noble metals and show some similarities to both copper and nickel systems, and also growth patterns have been identified. All vibrational frequencies of all the clusters have been calculated for the first time, and here we focus on the highest and lowest frequencies. Structural effects on the calculated frequencies were considered. [ABSTRACT FROM AUTHOR]

The large and growing volume of tire waste and sewage sludge requires disposal, for which thermochemical processes such as gasification can be used. Co-gasification of these two waste products allows the tire char to be used as a charge stabilizer and the sewage sludge to improve reactivity and efficiency. The purpose of this study was to evaluate the effect of the composition of a waste tire char and sewage sludge fuel blend on the gasification process, using steam as the gasification agent. Tests were carried out for tire char, municipal sewage sludge, and blends of the two in ratios of 90:10 and 67:33. An analysis of the materials used was carried out (ultimate and proximate analysis as well as ash composition), and isothermal measurements of steam gasification were taken using the thermal volumetric method for temperatures of 800, 850, and 900 °C at an elevated pressure of 1 MPa. On the basis of the results, the formation curves of the main gasification products (H2, CO, CO2, and CH4) were created, the curves for the degree of carbon conversion were plotted, the reactivity indexes were determined for different degrees of conversion (0.25, 0.5, and 0.75), and the quantity and composition of the resulting gas were analyzed. Using the grain model, the kinetic parameters (activation energy and pre-exponential factor) of the gasification reaction were calculated. The addition of municipal sewage sludge had a positive effect on the reactivity of tire char and increased the efficiency of gasification, because it contained components that act as catalysts in the gasification process. There was a favorable effect from the addition and higher amount of sewage sludge on lowering both the activation energy (49.5 kJ/mol and 89.2 kJ/mol for 90:10 and 67:33 blends, respectively) and the pre-exponential factor. A significant improvement in reactivity, with a high degree of conversion and the best gas composition, was obtained for a 90:10 blend at 900 °C. [ABSTRACT FROM AUTHOR]

The electronic structure and reactivity of 22 isorhodanine (IsRd) derivatives in the Diels–Alder reaction with dimethyl maleate (DMm) were investigated under two different environments (gas phase and continuous solvent CH 3 COOH ), using free Gibbs activation energy, free Gibbs reaction energy, and frontier molecular orbitals to analyze their reactivity. The results revealed both inverse electronic demand (IED) and normal electronic demand (NED) characteristics in the Diels–Alder reaction and also provided insights into the aromaticity of the IsRd ring by employing HOMA values. Additionally, the electronic structure of the IsRd core was analyzed through topological examination of the electron density and electron localization function (ELF). Specifically, the study demonstrated that ELF was able to successfully capture chemical reactivity, highlighting the potential of this method to provide valuable insights into the electronic structure and reactivity of molecules. [ABSTRACT FROM AUTHOR]

Alkali-activated materials (AAMs) result from the dissolution process and polycondensation of precursors in high pH solutions. This material is considered alternative cement with similar properties and lower environmental impact than Portland cement. However, AAMs are subjected to the same standardization applied to cement-based materials since no formal methods exist to characterize this material and/or the precursor reactivity. Therefore, this work aims to develop a method to characterize the reactivity of the main precursors used to produce AAMs. Hence, the precursors were assessed in two steps after chemical, physical, and mineralogical characterization. The first step evaluated the crystallinity change of the material after the acid attack by mixing 1 g of each material in 100 mL of 1% HF solution for 6 h at ambient temperature. The crystallinity change was evaluated by comparing the X-ray diffraction of the materials before and after the acid attack. The second step involved evaluating the formation of geopolymerization products in the pastes of studied precursors through FTIR test. The pastes were produced with Na2SiO3 and NaOH as activators. After 28 days of curing, the pastes were submitted to a FTIR test for structural analysis. This method was tested evaluating the reactivity of traditional precursors for alkali activation (i.e., silica fume (SF), blast furnace slag (BFS), and metakaolin (MK)), in addition sugarcane bagasse ash mechanically treated (SCBAM) and sugarcane bagasse ash mechanically and heat treated (SCBAMH) since SCBA is a promising precursor for alkali activation. Considering the crystallinity change of precursors (step 01), the formation of geopolymerization products (step 02), and the chemical composition of precursors (preliminary characterization), it could be concluded that: (i) surface area is not relevant to materials with small particle size (<23 µm); (ii) amorphous area is only relevant if the material exhibits the optimal chemical composition; and (iii) the chemical composition is a crucial parameter for alkali activation. In addition, the potential precursors for alkali activation should have a significant amorphous halo and a SiO2/Al2O3 ratio of 2 to 5. Also, it could be concluded that SF and SCBAMH do not exhibit adequate reactivity while BFS, MK, and SCBAM can be classified as reactive precursors. [ABSTRACT FROM AUTHOR]

Significant interest in waste-cement recycling has been stimulated because of the high contents of calcium and silicon in waste cement. The reactivity of calcium and silicon in the raw material is one of the important factors for the hydrothermal synthesis of xonotlite. Therefore, the effect of the reactivity of calcium and silicon in the waste cement on the hydrothermal synthesis of xonotlite was studied in this paper. Portland cement that was hydrated for 6 months, with the aim of simulating the waste cement, was used for the first time as the calcium and silicon source in the hydrothermal synthesis of xonotlite. As calcination would raise the reactivity of the hydrated cement, the effect of calcination of the Portland hydrated cement on the hydrothermal synthesis of xonotlite was investigated. The hydrated cement was calcined at 900 °C, and the hydrothermal synthesis was carried out at 220 °C for different times. The phases of the hydrothermal products were analyzed by XRD and TG-DSC, and it was noted that the calcination of hydrated cement affected the formation rate of xonotlite. The content of xonotlite increased from 18% (synthesized with hydrated cement without calcination) to 74% (synthesized from hydrated cement with calcination at 900 °C) during a reaction time of 24 h. Furthermore, the micromorphologies of xonotlite using calcined and hydrated cement were compared and discussed from the perspective of the reactivity of the starting materials. [ABSTRACT FROM AUTHOR]

This review summarizes data on the main types of charge-compensated nido-carborane derivatives. Compared with organic analogs, onium derivatives of nido-carborane have increased stability due to the stabilizing electron-donor action of the boron cage. Charge-compensated derivatives are considered according to the type of heteroatom bonded to a boron atom. [ABSTRACT FROM AUTHOR]

Organometallic approaches are of ongoing interest for the development of novel functional 99mTc radiopharmaceuticals, while the basic organotechnetium chemistry seems frequently to be little explored. Thus, structural and reactivity studies with the long-lived isotope 99Tc are of permanent interest as the foundation for further progress in the related radiopharmaceutical research with this artificial element. Particularly the knowledge about the organometallic chemistry of high-valent technetium compounds is scarcely developed. Here, phenylimido complexes of technetium(V) with different isocyanides are introduced. They have been synthesized by ligand-exchange procedures starting from [Tc(NPh)Cl3(PPh3)2]. Different reactivity patterns and products have been obtained depending on the steric and electronic properties of the individual ligands. This involves the formation of 1:1 and 1:2 exchange products of Tc(V) with the general formulae [Tc(NPh)Cl3(PPh3)(isocyanide)], cis- or trans-[Tc(NPh)Cl3(isocyanide)2], but also the reduction in the metal and the formation of cationic technetium(I) complex of the formula [Tc(isocyanide)6]+ when p-fluorophenyl isocyanide is used. The products have been studied by single-crystal X-ray diffraction and spectroscopic methods, including IR and multinuclear NMR spectroscopy. DFT calculations on the different isocyanides allow the prediction of their reactivity towards electron-rich and electron-deficient metal centers by means of the empirical SADAP parameter, which has been derived from the potential energy surface of the electron density on their potentially coordinating carbon atoms. [ABSTRACT FROM AUTHOR]

Understanding the catalytic performance of different materials is of crucial importance for achieving further technological advancements. This especially relates to the behaviors of different classes of catalysts under operating conditions. Here, we analyzed the effects of local coordination of metal centers (Mn, Fe, Co) in graphene-embedded single-atom catalysts (SACs). We started with well-known M@N4-graphene catalysts and systematically replaced nitrogen atoms with oxygen or sulfur atoms to obtain M@OxNy-graphene and M@SxNy-graphene SACs (x + y = 4). We show that local coordination strongly affects the electronic structure and reactivity towards hydrogen and oxygen species. However, stability is even more affected. Using the concept of Pourbaix plots, we show that the replacement of nitrogen atoms in metal coordinating centers with O or S destabilized the SACs towards dissolution, while the metal centers were easily covered by O and OH, acting as additional ligands at high anodic potentials and high pH values. Thus, not only should local coordination be considered in terms of the activity of SACs, but it is also necessary to consider its effects on the speciation of SAC active centers under different potentials and pH conditions. [ABSTRACT FROM AUTHOR]

In this paper, we study the asymptotic and transient dynamics of a predator–prey model with square root functional responses and random perturbation. Firstly, the mean square stability matrix is obtained from the stability theory of stochastic systems, and three stability indexes (root-mean-square resilience, root-mean-square reactivity and root-mean-square amplification envelope) of the ecosystem response to stochastic disturbances are calculated. We find that: (1) no matter which population is disturbed, increasing the intensity of disturbance improves the ability of the system leaves steady state and thus decreases the stability. The root-mean-square amplification envelope rises with increasing disturbance intensity, (2) the system is more sensitive to the disturbance of the predator than disturbance to prey, (3) ρ m a x and t m a x are important indicators, which represent the intensity and time of maximum amplification by disturbance. These findings are helpful for managers to take corresponding management measures to reduce the disturbances, especially for predators, thereby avoiding the possible change of the structure and functions of the ecosystem. [ABSTRACT FROM AUTHOR]

Elastic fibers, made of elastin (90%) and fibrillin-rich microfibrils (10%), are the key extracellular components, which endow the arteries with elasticity. The alteration of elastic fibers leads to cardiovascular dysfunctions, as observed in elastin haploinsufficiency in mice (Eln+/-) or humans (supravalvular aortic stenosis or Williams–Beuren syndrome). In Eln+/+ and Eln+/- mice, we evaluated (arteriography, histology, qPCR, Western blots and cell cultures) the beneficial impact of treatment with a synthetic elastic protein (SEP), mimicking several domains of tropoelastin, the precursor of elastin, including hydrophobic elasticity-related domains and binding sites for elastin receptors. In the aorta or cultured aortic smooth muscle cells from these animals, SEP treatment induced a synthesis of elastin and fibrillin-1, a thickening of the aortic elastic lamellae, a decrease in wall stiffness and/or a strong trend toward a reduction in the elastic lamella disruptions in Eln+/- mice. SEP also modified collagen conformation and transcript expressions, enhanced the aorta constrictive response to phenylephrine in several animal groups, and, in female Eln+/- mice, it restored the normal vasodilatory response to acetylcholine. SEP should now be considered as a biomimetic molecule with an interesting potential for future treatments of elastin-deficient patients with altered arterial structure/function. [ABSTRACT FROM AUTHOR]

Copolymers with two distinguished reactive repeating units are of great interest, as such copolymers might open the possibility of obtaining selective and/or consequent copolymers with different chemical structures and properties. In the present work, copolymers based on two active esters (pentafluorophenyl methacrylate and p-nitrophenyl methacrylate) with varied compositions were synthesized by Cu(0)-mediated reversible deactivation radical polymerization. This polymerization technique allows the preparation of copolymers with high to quantitative conversion of both comonomers, with moderate control over dispersity (Đ = 1.3–1.7). Additionally, by in-depth study on the composition of each copolymer by various techniques including elemental analysis, NMR, FT-IR, and XPS, it was possible to confirm the coherence between expected and obtained composition. Thermal analyses by DSC and TGA were implemented to investigate the relation between copolymers' composition and their thermal properties. Finally, an evaluation of the difference in reactivity of the two monomer moieties was confirmed by post-modification of copolymers with a primary amine and a primary alcohol as the model. [ABSTRACT FROM AUTHOR]

Pea-based ingredients are increasingly being used in foods because of their nutritional, functional and environmental benefits. However, their bitter taste is not appreciated by consumers. Saponins have been reported to be bitter in whole pea flour (PF) but not in the purified ingredients obtained from it, such as pea protein isolate (PPI) and pea starch (PS). In addition, the evolution of saponins in cooked foods made from these ingredients and their relationship to bitter flavor has not been investigated. This study, therefore, explored the presence of two bitter saponins, βg and Bb, in whole pea flour (PF) and a composite flour reconstructed from the two main fractions (PS + PPI). In addition, it investigated the impact of baking on the chemical state of these compounds in a sponge cake. Finally, the sensory impact of the baking process on the perceived bitterness of cakes made with these two pea flours was also evaluated. High-Performance Liquid Chromatography–High-Resolution Mass Spectrometry (HPLC-HRMS) was used to identify and quantify pea saponins in the flours and cakes, and a descriptive sensory analysis was obtained by a trained panel to assess sensory differences in bitterness. Our results showed marked differences in saponin concentration and composition among the pea ingredients studied. Concentrations were highest in PPI (1.497 mg·g−1 dry matter), with 98% of saponin Bb. PS had the lowest saponin concentration (0.039 mg·g−1 dry matter, with 83% Bb), while 0.988 mg·g−1 dry matter was quantified in PF, with only 20% Bb and 80% βg. This research also highlighted the thermal degradation of saponin βg to Bb in sponge cakes during baking at 170 °C. However, at a sensory level, these chemical changes were insufficient for the impact on bitterness to be perceived in cakes made with pea flour. Moreover, baking time significantly reduced the bitter flavor in cakes made with the composite flour (PS + PPI). [ABSTRACT FROM AUTHOR]

The hydration of M-S-H prepared using silica fume (SF) and dead-burned MgO cured at 20 °C, 50 °C, and 80 °C was investigated, and the properties and performance of this M-S-H were measured. The formation of M-S-H was characterized using XRD, FTIR, TGA, and 29Si MAS-NMR. Results show that the compressive strength of paste prepared using MgO calcined at 1450 °C for 2 h reached 25 MPa after 28 d. The shrinkage of mortar made with low reactivity MgO was lower than that made with high reactivity MgO. The pH value of MgO/SF paste mixed with dead-burned MgO did not exceed 10.4 at room temperature. The shrinkage of M-S-H prepared using dead-burned MgO was less than that prepared using more active MgO, and its strength did not decrease over time. No (or only a small amount of) Mg(OH)2 was formed, which is why the strength of M-S-H prepared with dead-burned MgO continually increased, without decreasing. The promotion of curing temperature favor process of MgO hydration and is beneficial for degree of silica polymerization. The sample cured in 50 °C water showed the highest relative degree of reaction. [ABSTRACT FROM AUTHOR]

Boron is one of the highest energy density materials. The heat of boron is difficult to carry out due to its poor combustion performance. Magnesium (10 wt.%), acting as combustion adjuvant, is added into boron powder to improve the combustion performance. In this study, two kinds of boron powder were used as raw material, boron powder with an average size of 40 μm is named B1, and B2 has an average powder size of 3 μm. Mg/B composite powder was prepared though a cryomilling method. Two compound mechanisms for Mg/B composite powder were applied. For Mg/B1 composite powder, an Mg-coating structure on the surface of B was generated. For Mg/B2, a structure that small particles were agglomerated with Mg in the interior or on the surface of B was generated. Compared with either B powder or blended Mg/B powder, the reactivity of Mg/B composite powder by cryomilling is enhanced. In addition, the atomic ratio of Mg to B and activity content of Mg on the surface of Mg/B composite powder have great impacts on the improvement of reactivity. [ABSTRACT FROM AUTHOR]

A mixture of hydraulic lime and pozzolanic material can be used as a binder in making concrete and mortar for energy-efficient construction purposes. Generally, lime possesses lower strength and higher setting time. By introducing pozzolans in the lime mortar, their cementitious properties could be increased and could compete with the cement mortars. The use of pozzolan-lime binder in mortar reduces the utilisation of cement, and hence reduces the environmental problem originating from cement production. This study mainly deals with the mechanical and microstructural properties of lime and lime composite mortars made up of hydraulic lime, silica fume and rice husk ash. Three composite mortars were made with the following combination such as hydraulic lime-silica fume (LSF), hydraulic lime-rice husk ash (LRA) and hydraulic lime-silica fume-rice husk ash (LSR). Further, their properties were compared with the pure lime mortar. Preliminary investigations were made on the lime reactivity and pozzolanic reactivity tests. It was understood that silica fumes have a (15%) better reactivity than rice husk ash. The introduction of pozzolans in the lime mortar promotes fresh, hardened and microstructural properties. The 28 days' compressive strength of lime composite mortars achieved more than 16 Mpa, while the lime mortar attained 4 Mpa. The combined effect of pozzolanic reaction, hydration and carbonation in the lime composite mortars achieved four times the strength of lime mortar at 28 days. A high peak of calcium carbonate was detected in lime mortar as a result of carbonation. The well-developed microstructure of calcium silicate hydrate and calcium hydroxide exhibits the formation of hydration products in the lime composite mortars as observed from a scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Similar graphs of Fourier transform infrared spectroscopy (FT-IR) showed the presence of equivalent functional elements in all lime composite mortars. [ABSTRACT FROM AUTHOR]

A thermodynamic model was proposed to calculate the activity of components in low-reactive CaO-BaO-Al2O3-SiO2-CaF2-Li2O mold flux, which was chosen to improve the castability of high Al steel, based on the ion and molecular coexistence theory. The model was indirectly validated, and the effects of the mass ratio of Al2O3/SiO2, contents of CaF2 and Li2O on the reactivity of components were discussed. The results reveal that the reactivity of mold flux attenuated with the increase in the mass ratio of Al2O3/SiO2. The decrease in reactivity was insignificant as the mass ratio was over 3.5. The steel–slag reaction experiment confirmed that the reactivity of mold flux is weakened when the content of SiO2 below 8 wt%. The reactivity of mold flux increased nearly linearly with the increase in CaF2 content, indicating that the proportion of CaF2 should be kept to a minimum in the flux. In addition, the compositional regions involving around 6 wt% Li2O should be avoided to develop low-reactive mold flux. [ABSTRACT FROM AUTHOR]

Vinylpyrazoles, also known as pyrazolyl olefins, are interesting motifs in organic chemistry but have been overlooked. This review describes the properties and synthetic routes of vinylpyrazoles and highlights their versatility as building blocks for the construction of more complex organic molecules. Concerning the reactivity of vinylpyrazoles, the topics surveyed herein include their use in cycloaddition reactions, free-radical polymerizations, halogenation and hydrohalogenation reactions, and more recently in transition-metal-catalyzed reactions, among other transformations. The current state of the art about vinylpyrazoles is presented with an eye to future developments regarding the chemistry of these interesting compounds. Styrylpyrazoles were not considered in this review, as they were the subject of a previous review article published in 2020. [ABSTRACT FROM AUTHOR]

The [3+2] cycloaddition (32CA) reaction of an azomethine ylide (AY), derived from isatin and L-proline, with phenyl vinyl sulphone has been studied within Molecular Electron Density Theory (MEDT) at the ωB97X-D/6-311G(d,p) level. ELF topological analysis of AY classifies it as a pseudo(mono)radical species with two monosynaptic basins at the C1 carbon, integrating a total of 0.76 e. While vinyl sulphone has a strong electrophilic character, AY is a supernucleophile, suggesting a high polar character and low activation energy for the reaction. The nucleophilic Parr functions indicate that the pseudoradical C1 carbon is the most nucleophilic center. The 32CA reaction presents an activation Gibbs free energy of 13.1 kcal·mol−1 and is exergonic by −26.8 kcal·mol−1. This reaction presents high endo stereoselectivity and high meta regioselectivity. Analysis of the global electron density transfer (GEDT) at the most favorable meta/endo TS, 0.31 e, accounts for the high polar character of this 32CA reaction, classified by forward electron density flux (FEDF). A Bonding Evolution Theory (BET) study along the most favorable meta/endo reaction path characterizes this 32CA reaction, taking place through a non-concerted two-stage one-step mechanism, as a pseudo(mono)radical-type 32CA reaction, in agreement with the ELF analysis of the AY. [ABSTRACT FROM AUTHOR]

This review article discusses the effects of inorganic content and mechanisms on raw biomass and char during gasification. The impacts of the inherent inorganics and externally added inorganic compounds are summarized based on a literature search from the most recent 40 years. The TGA and larger-scale studies involving K-, Ca-, and Si-related mechanisms are critically reviewed with the aim of understanding the reaction mechanisms and kinetics. Differences between the reaction pathways of inorganic matter, and subsequent effects on the reactivity during gasification, are discussed. The present results illustrate the complexity of ash transformation phenomena, which have a strong impact on the design of gasifiers as well as further operation and process control. The impregnation and mixing of catalytic compounds into raw biomass are emphasized as a potential solution to avoid reactivity-related operational challenges during steam and CO2 gasification. This review clearly identifies a gap in experimental knowledge at the micro and macro levels in the advanced modelling of inorganics transformation with respect to gasification reactivity. [ABSTRACT FROM AUTHOR]

The search for new ways to obtain analogues of the well-known Methylene Blue dye is an important synthetic task. Herein, we proposed and developed an approach to the synthesis of 3-N′-arylaminophenothiazines and asymmetrical 3,7-di(N′-arylamino)phenothiazines. This approach included the optimization of synthetic strategy by quantification analysis of the positive charge distribution in the cation of 3-N′-arylaminophenothiazine derivative. The obtained experimental data are confirmed by DFT studies. Two synthetic routes for asymmetrical phenothiazine diarylamino derivatives were suggested and verified. The developed convenient and versatile synthetic approach makes it easy to obtain aromatic Methylene Blue isostructural analogues with various substituents. As a result, a series of novel 3-N′-arylaminophenothiazines and asymmetrical 3,7-di(N′-arylamino)phenothiazines containing ester, tert-butoxycarbonyl, sulfonic acid, hydroxyl and amine groups were obtained in high yields. [ABSTRACT FROM AUTHOR]

Numerous benzothiazole derivatives are used in organic synthesis, in various industrial and consumer products, and in drugs, with a wide spectrum of biological activity. As the properties of the benzothiazole moiety are strongly affected by the nature and position of substitutions, in this review, covering the literature from 2016, we focus on C-2-substituted benzothiazoles, including the methods of their synthesis, structural modification, reaction mechanisms, and possible pharmacological activity. The synthetic approaches to these heterocycles include both traditional multistep reactions and one-pot atom economy processes using green chemistry principles and easily available reagents. Special attention is paid to the methods of the thiazole ring closure and chemical modification by the introduction of pharmacophore groups. [ABSTRACT FROM AUTHOR]